JP2005233050A - Hydraulic pump control device, and control method for hydraulic pump control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly change a flow control state and a pressure control state from each other in short time in simple constitution, facilitate adjustment, and achieve favorable control characteristics. <P>SOLUTION: This hydraulic pump control device 1 comprises a control operation part 10 to output a rotation number command signal IR to a rotation number control means 40, that is provided with a first operation element 11, a second operation element 12, and a limiting circuit 20. The first operation element 11 is provided with a parallel circuit of an integrating and amplifying part 16 for deviation between delivery pressure command values Pc and delivery pressure detecting values P, and a feedback amplifying part 19 of differentiating elements of order zero or over of the delivery pressure detecting values P coupled in parallel. The limiting circuit 20 takes inputs of a first signal outputted from the first operation element 11 and a second signal outputted from the second operation element 12 to limit the first signal by the second signal in outputting the rotation number command signal IR. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic pump control device that controls a discharge flow rate of a hydraulic pump, a discharge pressure of the hydraulic pump, a speed of a load connected to the hydraulic pump, a generation force of the load connected to the hydraulic pump, And a control method of the hydraulic pump control device.

  The hydraulic pump is widely used as a power source for various industrial machines including a press device and an injection molding machine because of its small size and high output. In this case, the hydraulic energy generated by the hydraulic pump is converted into kinetic energy and motive energy through cylinders, motors, etc. (hereinafter collectively referred to as actuators) incorporated in industrial machinery, and thus industrial Various machine operations are performed. That is, the pressure of the liquid generated by the hydraulic pump is converted into the generated force and generated torque of the actuator, and the flow rate (flow velocity) of the liquid generated by the hydraulic pump is converted into the straight speed and rotational speed of the actuator. Therefore, the operation of the industrial machine can be controlled by controlling the pressure of the liquid generated by the hydraulic pump and the flow rate (flow velocity) of the liquid.

  When controlling industrial machines such as press machines and injection molding machines, controlling the moving speed of workpieces and molds with actuators and controlling the force applied to workpieces and molds These correspond to the state of speed or flow control (hereinafter collectively referred to as flow control) and the state of force or pressure control (hereinafter collectively referred to as pressure control). For example, in a state where the mold is driven at a certain speed, when the mold stops against a stationary member or the like, it is necessary to quickly switch from flow control to pressure control. Thus, when operating an industrial machine with a hydraulic pump, it is necessary to continuously and smoothly switch the flow rate control state and the pressure control state in the control of the hydraulic pump.

  Therefore, many proposals and practical applications have been made for the flow rate and pressure control methods of hydraulic pumps. Many of these conventional hydraulic pump control devices change the discharge capacity of a variable displacement hydraulic pump operated at a constant rotational speed by an electric motor (that is, the theoretical discharge volume per one rotation of the pump). A method of controlling the flow rate and pressure of the liquid discharged from the liquid is taken. According to this method, since the switching between the flow rate control and the pressure control is switched by one means (element) called the theoretical discharge volume per rotation of the hydraulic pump, the control state is switched between the flow rate control state and the pressure control state. There is an advantage that can be performed smoothly. However, the structure of the variable displacement hydraulic pump itself is complicated, the control system constituting the discharge capacity changing means is complicated, the flow rate control characteristics in the low pressure region are inferior, and the hydraulic pump During this operation, the motor must continue to rotate regardless of whether or not the discharge capacity is present. Therefore, in order to solve these problems, the discharge flow rate and the discharge pressure of the hydraulic pump are controlled by controlling the rotation speed using a fixed displacement type hydraulic pump.

  However, in the control of the discharge pressure and the discharge flow rate by controlling the rotation speed of the fixed displacement hydraulic pump, the control amount is discontinuous when the control state is switched between the pressure control state and the flow rate control state. And is often known to exhibit unstable behavior. For this reason, various techniques for realizing smooth switching between the pressure control and the flow rate control have been proposed in the rotational speed control of the hydraulic pump. Examples of the techniques described in Patent Documents 1 to 4 have been proposed. was there.

  For example, as shown in FIG. 6, the control device described in Patent Document 1 includes a deviation ΔP between the pressure command value Pc and the pressure detection value P of the discharge pressure of the hydraulic pump 106 detected by the pressure detection means 107, and the flow rate. Deviation ΔQ between the command value Qc and the flow rate detection value Q detected by the rotation speed detection means 108 for detecting the rotation speed of the servo motor 105 is input to the pressure control compensation element 101 and the flow rate control compensation element 102, respectively. Of the outputs from the control compensation element 101 and the flow rate control compensation element 102, the smaller one is selected by the minimum value selection circuit 103 and output to the servo amplifier 104. The pressure control compensation element 101 and the flow rate control compensation element 102 are each composed of a parallel circuit of a proportional amplifier, an integral amplifier, and a differential amplifier. In the control device 100 shown in FIG. 6, when the pressure control and the flow rate control are switched, the output of the pressure control compensation element 101 and the output of the flow rate control compensation element 102 coincide with each other. In addition to realizing the smooth switching, the gains of the pressure control compensation element 101 and the flow rate control compensation element 102 can be set independently, so that good control characteristics can be obtained.

  In addition, in the control device described in Patent Document 2, instead of using the minimum value selection circuit, the output from the flow control compensation element (speed FB calculator) and the pressure control compensation element (pressure FB calculator) are used. Using a selection circuit that switches the output arbitrarily, at the time of switching between speed control and pressure control, find the variable of the integral term of the deviation of the PID compensator based on the output of one compensation element before switching, and switch this By adopting a method of setting as an initial value of the integral term of the PID compensator of the other compensation element section later, the output is prevented from becoming discontinuous when switching between pressure control and speed control.

  In the control device described in Patent Document 3, as shown in FIG. 7, a deviation ΔP between the pressure command value Pc and the detected pressure value P is input to the pressure control compensation element 111, and A value obtained by adding the output and the detection value of the rotation speed detection means 115 via the non-proportional function unit 118 and the flow rate command value Qc are compared by the minimum value selection circuit 112, and the smaller one of these values. Is selected and output as the rotational speed command signal IR, and the rotational speed command signal IR is compared with the rotational speed detection signal I from the rotational speed detection means 115 to compare the amplifier (and the rotational speed control compensation circuit included therein) 114. It is set as the structure applied to. In this control device 110, the non-proportional function of the non-proportional function unit 118 has a dead zone in the portion where the input is close to zero, and the gain in the other portions is a function close to 1, so the discharge pressure of the hydraulic pump 117 (Pressure detection value) When the pressure P reaches the vicinity of the pressure command value Pc and the control of the hydraulic pump 117 switches to the pressure control state, the continuity of the output value of the minimum value selection circuit 112 is maintained. Switching of the control state can be realized.

  On the other hand, in the control device described in Patent Document 4, as shown in FIG. 8, when the difference ΔP between the pressure detection value P and the pressure command value Pc by the pressure detection means 125 is equal to or higher than a predetermined limit level. Is provided with limiter means 122 so that the pressure control compensation element 121 generates an output signal of a constant level, and the sum or product of the output of the limiter means 122 and the flow rate command value Qc is preferentially outputted to the rotation speed control means 124. Thus, the selection circuit 123 is configured. According to this control device 120, since the output of the pressure control compensation element 121 is always included in the rotational speed command signal IR to the rotational speed control means 124, the rotational speed command signal IR is not effective when switching between flow control and pressure control. Not continuous.

  As described above, in the conventional hydraulic pump control device, the configuration of the selection circuit and the compensation element is devised in order to smoothly switch between the flow rate control and the pressure control and to obtain good flow rate / pressure characteristics. In these conventional flow rate / pressure control devices based on the rotational speed control of the hydraulic pump, pressure control is realized by proportional / integral / differential compensation (PID compensation) based on the deviation between the pressure command value and the pump discharge pressure. ing.

  Here, a specific example of operation control in a region where pressure control is actually performed will be described. In the following, pressure control and flow rate control will be described. However, in actual driving by a hydraulic pump, the discharge pressure of the hydraulic pump is converted into the generated force of the actuator, and the discharge flow rate is converted into the speed of the actuator. This can be achieved by replacing the control of the discharge pressure with the control of the generated force of the actuator and the control of the discharge flow rate with the control of the speed of the actuator.

一方、圧力指令値と検出された実際の圧力検出値との偏差のＰＩＤ補償により圧力制御を行う場合には、ＰＩＤ補償器の出力ｎ_Ｃは、圧力指令値Ｐｃ，比例ゲインＫ_Ｐ，積分ゲインＫ_Ｉ，微分ゲインＫ_Ｄとすると、

となる。ここで、ＰＩＤ補償器の出力ｎ_Ｃは圧力制御時のポンプ回転数ｎと略一致するから、ｎ_Ｃ＝ｎとおいて、〔数２〕を〔数１〕に代入してラプラス変換を行い、圧力制御系の伝達関数Ｆ（ｓ）をラプラス演算子ｓを用いて表すと、

となる。 In the region where pressure control is actually performed, the discharge of the hydraulic pump is restricted and the working fluid is compressed to increase the pressure. A typical example of this is a case where the cylinder that is the load reaches the end of the stroke, the discharge of the hydraulic pump is blocked, and the load becomes only the volume inside the cylinder or the pipe. At this time, the pump discharge pressure P, the discharge volume D per pump rotation, the pump rotation speed n, the pump leakage coefficient K _L , the pipe and load volume V _T after the pump discharge section, and the equivalent volume elastic coefficient κ , [Equation 1] holds from the flow rate continuity equation.

On the other hand, when pressure control is performed by PID compensation of the deviation between the pressure command value and the detected actual pressure value, the output n _C of the PID compensator is the pressure command value Pc, proportional gain K _P , integral gain. K _I, when the derivative gain _{K D,}

It becomes. Here, since the output n _C of the PID compensator substantially coincides with the pump rotational speed n at the time of pressure control, with n _C = n, [Formula 2] is substituted into [Formula 1] to perform Laplace transform, When the transfer function F (s) of the pressure control system is expressed using the Laplace operator s,

It becomes.

  However, as is clear from [Equation 3], this pressure control system has a zero in the transfer function F (s) due to the PID compensation gain (that is, a s polynomial in the numerator of the transfer function F (s). ). Therefore, when the proportional, integral, and differential gains are adjusted, the coefficients of the denominator polynomial and numerator polynomial of the transfer function F (s) change, but the response of the pressure control system depends on both the pole and zero of the transfer function. As a result, the response of the pressure control system changes in a complicated manner when each gain is adjusted. For this reason, there is a problem that it is difficult to adjust the gain of PID compensation.

  Essentially, only the numerator polynomial of the transfer function needs to be adjusted in order to adjust the response of the pressure control system. From this point of view, the conventional PID compensation pressure control system has a large number of terms in the numerator polynomial in the transfer function F (s). For this reason, the forward control input is excessive with respect to the input necessary for adjusting the characteristics of the pressure control system. As described above, in the conventional pressure control system, since excessive input is given, it is necessary to set each control gain low in order to perform stable operation, and it becomes difficult to obtain good control characteristics after all. It was. Note that this problem does not occur if the compensation element is only proportional compensation, but there is another problem that a steady-state deviation remains when integral compensation is not used.

  On the other hand, these conventional hydraulic pump control devices need to incorporate the rotational speed of the hydraulic pump into a control element and to implement a complicated selection control mechanism. For this reason, the configuration of the hydraulic pump control device is complicated and expensive, and in addition to setting the control parameters based on the rotational speed of the hydraulic pump and setting the switching width due to pressure deviation, the characteristics of the pressure control system In addition, since it interferes with the characteristics at the time of switching between the pressure control and the flow rate control, there is a problem that the configuration of the hydraulic pump control device becomes complicated and the adjustment becomes more difficult.

  In the conventional hydraulic pump control device, when the pressure command value increases stepwise, the pressure control state may be switched to the flow rate control state. That is, in the pressure control state, the discharge pressure of the hydraulic pump is generated by restricting the discharge flow rate of the hydraulic pump by the actuator connected as a load, and the actual discharge flow rate of the hydraulic pump is the flow rate The discharge flow rate is always smaller than the command value. Therefore, when the pressure command value increases stepwise, the output of the pressure control compensation element may increase rapidly and exceed the output of the flow control compensation element. As a result, when the pressure control state is switched to the flow rate control state, the servo motor that has been rotating at a low rotational speed will suddenly change to a rotational speed that discharges a large amount of flow, but the rotational speed of the hydraulic pump If the connected load remains blocked even if the pressure rises suddenly, the discharge pressure rises sharply, and in some cases, a high surge pressure is generated, and an impact force is also generated in the actuator connected as the load. There was a problem of doing.

  Furthermore, when the load pressure or load generation force increases sharply and the detected pressure value is equal to or higher than the pressure command value, the output of the pressure control compensation element decreases rapidly and returns to the pressure control state again. . Then, since the rotation speed of the hydraulic pump rapidly decreases, the pressure of the load decreases, and again enters the flow rate control state, the hydraulic pump rotation speed is rapidly increased, and the load pressure rapidly increases. There was a case where a so-called chattering phenomenon occurred. In particular, when the gain of pressure control is high, it has been a problem that such an unstable operation is likely to occur.

  Further, in a control device that switches the control state using a deviation between the pressure command value and the detected pressure value, as in the control device shown in Patent Document 4, for example, the control state is switched depending on the width of the deviation. As the pressure deviation rapidly increases, the output of the pressure control compensation element increases rapidly and the flow control state is entered. Therefore, with this type of conventional control device, an unstable behavior associated with switching between the pressure control state and the flow rate control state is exhibited for any step change in the pressure command value, regardless of whether the pressure command value is increased or decreased. There was a problem that could indicate.

In order to suppress the occurrence of a pressure surge when the pressure command value increases stepwise, it is effective to limit the rate of change of the rotation speed of the hydraulic pump. However, if the rate of change of the number of revolutions of the hydraulic pump is constant, the change in pressure is faster when the load volume is small, and the change in pressure is slower when the load volume is large. In order to suppress the occurrence of a pressure surge when the pressure is small, it is necessary to set the rate of change of the rotational speed to be kept constant at a small value. However, if the rate of change in the rotational speed is set to a small value, an extremely long time is required to increase the pressure when a load having a large volume is connected to the hydraulic pump. For this reason, it is difficult to set an appropriate rate of change of the rotational speed, and conventionally, the rate of change of the rotational speed of the hydraulic pump has not been limited.
Japanese Patent No. 3171473 Japanese Patent No. 3253387 Japanese Patent Laid-Open No. 10-13186 International Application Patent WO01 / 006126A1

  The present invention has been made paying attention to the problems of these conventional hydraulic pump control devices, and can switch the control state between the flow rate control state and the pressure control state smoothly and in a short time. However, it is an object of the present invention to provide a hydraulic pump control device and a control method for the hydraulic pump control device that can be easily adjusted, can be easily adjusted, and can obtain good control characteristics.

  In order to solve the above problems, the invention described in claim 1 of the present application includes a hydraulic pump, a rotational speed control means for controlling the rotational speed of the hydraulic pump to coincide with a rotational speed command signal, and a hydraulic pump. The discharge pressure of the hydraulic pump and the discharge flow rate of the hydraulic pump, or the discharge pressure and the hydraulic pressure of the hydraulic pump, comprising a pressure detection means for detecting the discharge pressure of the hydraulic pump and a control calculation unit for outputting the rotation speed command signal A hydraulic pump control device for controlling the speed of a load connected to a pump, wherein a control calculation unit is inputted to a rotation speed control means from a discharge pressure detection value by a pressure detection means and a changeable pressure command value A first calculation element that outputs a signal corresponding to the rotation speed command signal, and a rotation speed control means based on the discharge rate per rotation of the hydraulic pump from the load speed command value or the discharge flow rate command value of the hydraulic pump Speed command signal input to A second computing element that outputs a corresponding signal; and a limiting circuit that limits the output of the first computing element with the output of the second computing element and outputs a rotational speed command signal. Is configured to include a parallel circuit of an integral amplifying unit for deviation between the discharge pressure detection value and the discharge pressure command value and a feedback amplification unit in which a differential element of zeroth order or higher of the discharge pressure detection value itself is coupled in parallel. It is characterized by that.

  According to a second aspect of the present invention, there is provided a hydraulic pump, rotational speed control means for controlling the rotational speed of the hydraulic pump so as to coincide with the rotational speed command signal, and a load connected to the hydraulic pump. Connected to the generating force of the load connected to the hydraulic pump and the discharge flow rate of the hydraulic pump, or the hydraulic pump, including force detecting means for detecting the generated force and a control calculation unit for outputting the rotational speed command signal A hydraulic pump control device for controlling the generated load generation force and the load speed connected to the hydraulic pump, wherein the control calculation unit is configured to detect the load generation force detected by the force detection means and the changeable force. A first calculation element that outputs a signal corresponding to a rotation speed command signal input to the rotation speed control means from the command value, and one rotation of the hydraulic pump from the load speed command value or the discharge flow rate command value of the hydraulic pump Input to the rotational speed control means based on the discharge volume per unit A second calculation element that outputs a signal corresponding to the rotation speed command signal, and a limit circuit that outputs the rotation speed command signal by limiting the output of the first calculation element with the output of the second calculation element. The first calculation element is a feedback in which an integral amplifying unit for deviation between a load generation force detection value and a load force command value and a zero-order or higher differential element of the load generation force detection value itself are coupled in parallel. It is characterized by comprising a parallel circuit with an amplifying unit.

  As described above, in the first and second aspects of the invention, in the limiting circuit, the second calculation element corresponds to the rotation speed command signal output based on the discharge amount per rotation of the hydraulic pump. The signal (second signal) is configured to limit the signal (first signal) corresponding to the rotation speed command signal output from the first calculation element. Thus, when the discharge pressure of the hydraulic pump is significantly lower than the discharge pressure command value (that is, when the load pressure does not reach the discharge pressure command value and flow control is to be performed), the discharge pressure command value The output of the first calculation element is increased by the function of the integral amplifying unit for the deviation of the detected discharge pressure value. Even in this case, the second signal is output from the limiting circuit, and the control state of the hydraulic pump control device is The flow control state is entered.

  On the other hand, when the deviation between the discharge pressure command value and the discharge pressure detection value is small, the first signal is small, so the first signal is output from the limiting circuit as it is, and the pressure control state is entered. Further, at the time of switching between the pressure control state and the flow rate control state, the output of the first signal decreases, and when the output coincides with the output of the second signal, the output from the limiting circuit changes from the second signal to the second signal. Since the signal is switched to one signal, the continuity of the output of the limiting circuit is maintained. Thus, smooth switching between the flow rate control state and the pressure control state can be realized.

  In the first and second aspects of the invention, the first calculation element is an integral amplification of a deviation between the discharge pressure command value or the load force command value and the discharge pressure detection value or the load generation force detection value. Adjustment of various characteristics in the pressure control of the hydraulic pump is facilitated by the configuration including the parallel circuit of the feedback amplifier unit in which the differential unit of the zeroth order or higher of the force detection value is coupled in parallel . Hereinafter, this point will be described in detail.

となる。ここで、〔数４〕の右辺の第１項が積分増幅部の出力に相当し、第２項がフィードバック増幅部の出力に相当する。〔数４〕をラプラス変換して、ｎ_C＝ｎとおいて〔数１〕に代入した圧力制御系は、

で表される零点を有しない２次の伝達関数となる。この〔数５〕から、この圧力制御系において、圧力の応答速度と定常特性を改善するためには積分増幅部のゲインＫ_Ｉを調整し、安定性を改善するためにはフィードバック増幅部の零次ゲインＫ_Ｐを調整すればよいことがわかる。また、この圧力制御系は偏差の積分補償を含むため、〔数５〕の分子と分母の０次の項は一致しており、定常偏差を除去する特性は維持されている。 First, consider a case where the first computing element in the feedback amplifier unit the zero-order differential element (the gain and K _P) was constituted of only the for simplicity. The output (first signal) of the first arithmetic element configured to include a parallel circuit of the integral amplifier and the feedback amplifier is:

It becomes. Here, the first term on the right side of [Equation 4] corresponds to the output of the integral amplifier, and the second term corresponds to the output of the feedback amplifier. The pressure control system obtained by performing Laplace transform of [Equation 4] and substituting it into [Equation 1] with n _C = n is

A second-order transfer function having no zero point represented by From this [equation 5], in the pressure control system, in order to improve the response speed and steady-state characteristics of the pressure by adjusting the gain K _I of integrating amplifier unit, in order to improve the stability of the feedback amplifier unit zero It can be seen that the next gain K _P may be adjusted. Further, since this pressure control system includes integral compensation of deviation, the numerator of [Equation 5] and the zero-order term of the denominator coincide with each other, and the characteristic of removing the steady deviation is maintained.

となり、〔数５〕は、分母第１項にゲインＫ_Ｄが付加された、

で表される伝達関数となる。上記のようにフィードバック増幅部に１次の微分要素を付加することで分母第１項をゲインＫ_Ｄにより調整できるため、この圧力制御系の時定数の調整も容易に実現することができる。 Further, if adding a first-order differential element in the feedback amplifier of the first computing element (the gain and K _D), [Equation 4],

Next, [Expression 5], the gain K _D of is added to the denominator first term,

The transfer function is expressed as Since the denominator first term by adding the first-order derivative component in the feedback amplifier part as described above can be adjusted by a gain K _D, it can also be easily realized adjustment of the time constant of the pressure control system.

  In the above example, the rotational speed of the hydraulic pump and the rotational speed command signal are derived as the same, but the rotational speed and rotational speed command signal of the hydraulic pump that are actually controlled by the rotational speed control means. There may be some delay between the two. Also in this case, in order to compensate for the higher order coefficient of the denominator polynomial corresponding to the delay from the rotational speed command signal to the hydraulic pump rotational speed, a differential element of the corresponding order is added to the feedback amplifier. That's fine. In this way, the feedback amplifying unit in which the differential element of the zeroth or higher order of pressure is connected in parallel to the integral amplifying unit of the pressure deviation is connected in parallel, so that only the coefficient of the denominator polynomial in the transfer function can be arbitrarily set. The pressure control system can be easily adjusted.

  That is, in the hydraulic pump control device according to claim 1 and claim 2, the feedback amplification unit is configured by connecting differential elements of zeroth order or higher of the hydraulic pump discharge pressure in parallel. The portion is not subjected to excessive forward input by the discharge pressure command signal, and the gain of the entire pressure control system can be increased as compared with the conventional hydraulic pump control device. Therefore, not only the adjustment of the pressure control system is facilitated, but also a hydraulic pump control device capable of obtaining a better pressure control characteristic.

  In the second aspect of the invention, since the generated force of the load connected to the hydraulic pump is directly detected and used for controlling the hydraulic pump, the discharge pressure of the hydraulic pump is used in the above description. It is possible to replace this control with the control of the generated force of the actuator.

  According to a third aspect of the present invention, in the hydraulic pump control device according to the first or second aspect of the present invention, the limiting circuit uses the output of the second arithmetic element as the discharge pressure detection value or force detection of the pressure detection means. The correction is performed based on the generated force detection value of the means.

  By adopting such a configuration, not only can the discharge flow rate reduction due to the leakage characteristics of the hydraulic pump be compensated in the flow rate control state, but also, for example, the discharge flow rate can be gradually reduced depending on the discharge pressure. It is possible to arbitrarily create a pressure / flow rate characteristic in which the discharge flow rate increases.

  Further, the hydraulic pump control device according to claim 4 is the hydraulic pump control device according to any one of claims 1, 2, or 3, and detects a change in a pressure command value or a load force command value. A change rate setting means for setting a change rate of the rotational speed command signal, and a delay time set in advance after the change of the pressure command value or the force command value is detected by the switch detection means. And a delay means for changing the rotational speed command signal at the change rate set by the change rate setting means.

  By adopting such a configuration, even when the pressure command value increases stepwise, the rotation speed command signal can be changed at a preset change rate during the delay time, so that the rotation of the hydraulic pump The rapid increase of the number can be suppressed.

  Further, even when the pressure command value is reduced stepwise, the first calculation element is provided only when the output of the integral amplification unit included in the first calculation element is decreased and the pressure detection value does not change suddenly. The output of the feedback amplifier does not change greatly, and the control state of the hydraulic pump control device remains in the pressure control state. Therefore, since it is structurally stable with respect to the step change of the pressure command value, there are few factors of destabilization.

  The hydraulic pump control device according to claim 5 is the hydraulic pump control device according to claim 4, wherein an adaptive identifier for estimating at least a volume of a load connected to the hydraulic pump, and the adaptive identifier Delay time changing means for changing the delay time of the delay means based on the output. Here, the adaptive identifier is assumed to estimate at least the volume of the load connected to the hydraulic pump. However, the function of the adaptive identifier is not limited to this, and is input to, for example, the hydraulic pump control device. You may comprise so that an equivalent bulk modulus, a ratio of a load volume and a bulk modulus, etc. can be estimated using an element (for example, load speed etc.).

  By adopting such a configuration, the delay time can be changed based on the output of the adaptive identifier, so an appropriate delay time can be set according to the volume of the load connected to the hydraulic pump. Switching from the pressure control state to the flow rate control state can be performed in a short time.

  The invention according to claim 6 is the control method of the hydraulic pump control device according to claim 4, wherein in the delay means, the discharge pressure detection value of the pressure detection means or the generated force detection value of the force detection means. The change rate of the rotation speed command signal is calculated based on the change rate of the rotation speed and the rotation speed command signal, and the change rate of the rotation speed command signal is limited by the calculated change rate during a preset delay time. It is characterized by doing.

  When the pressure command value or force command value increases rapidly and the hydraulic pump control device shifts from the pressure control state to the flow rate control state, the discharge pressure of the hydraulic pump or the generated force of the load connected to the hydraulic pump The rate of change varies depending on the volume of the load connected to the hydraulic pump, but at the same time also depends on the rotational speed of the hydraulic pump at that time. Therefore, by calculating the rate of change of the rotational speed of the hydraulic pump during the delay time based on the rate of change of the generated pressure of the discharge pressure or load and the rotational speed command signal as described above, at an appropriate rotational speed. The hydraulic pump can be operated.

  According to a seventh aspect of the present invention, in the control method for the hydraulic pump control device according to the sixth aspect, the rate of change of the discharge pressure detection value of the pressure detection means or the load generation force detection value of the force detection means Based on the above, at least the volume of the load connected to the hydraulic pump is estimated, the estimated value is calculated, and a preset delay time is changed based on the estimated value.

  The rate of change of the discharge pressure of the hydraulic pump varies depending on the volume of the load connected to the hydraulic pump and the rotational speed of the hydraulic pump. Therefore, based on the rate of change of the discharge pressure and the number of rotations of the hydraulic pump, it is possible to calculate the estimated value by calculating back the volume of the load connected to the hydraulic pump, and based on this estimated value of the load. In addition, by determining the delay time, an appropriate delay time can be set even when the load volume is large.

According to the invention described in each claim, the following excellent effects can be obtained.
According to the first and second aspects of the present invention, the control calculation unit converts the detected value of the discharge pressure by the pressure detecting means and the changeable pressure command value into the rotation speed command signal input to the rotation speed control means. The first calculation element that outputs a corresponding signal and the rotation input to the rotation speed control means based on the discharge amount per rotation of the hydraulic pump from the load speed command value or the discharge flow rate command value of the hydraulic pump A second computing element that outputs a signal corresponding to the number command signal, and a limiting circuit that limits the output of the first computing element with the output of the second computing element and outputs a rotation speed command signal Therefore, by maintaining the continuity of the output from the control calculation unit, smooth switching between the flow rate / speed control state and the pressure / force control state can be realized, and the hydraulic pump is in a stable state. Hydraulic pump with excellent characteristics to operate with It is possible to provide a control device.

  According to the first and second aspects of the present invention, the first calculation element includes an integral amplification unit for the deviation between the discharge pressure / force command value and the discharge pressure / force detection value, and the discharge pressure / force. Hydraulic pump control with easy pressure adjustment and good pressure / force control characteristics by having a parallel circuit composed of a feedback amplification unit in which differential elements of zero or higher order of the detected value are coupled in parallel An apparatus can be provided.

  Further, according to the first and second aspects of the present invention, since it is not necessary to feed back the rotation speed of the hydraulic pump to the control calculation unit, the configuration of the hydraulic pump control device becomes simple, inexpensive and reliable. A highly reliable hydraulic pump control device can be provided.

  According to the third aspect of the invention, since the output of the second calculation element is corrected by the discharge pressure detection value of the pressure detection means or the generated force detection value of the force detection means, an accurate pressure / force can be obtained. It is possible to provide a hydraulic pump control device that can perform control and flow / speed control, and can create arbitrary pressure / force characteristics and flow / speed characteristics.

  According to the fourth aspect of the present invention, the switching detection means for detecting a change in the pressure command value or the force command value of the load, the change rate setting means for setting the change rate of the rotational speed command signal, and the switching detection means. A delay means for changing the rotation speed command signal at a change rate set by the change rate setting means for a preset delay time after a change in pressure command value or force command value is detected by Thus, even when the pressure / force command value changes stepwise, it is possible to suppress a sudden change in the rotational speed of the hydraulic pump, and to prevent a pressure surge or shocking force from being generated in the load. Therefore, it is possible to provide a highly reliable hydraulic pump control device that is structurally stable against sudden changes in the command signal. For this reason, it is possible to prevent damage, vibration, noise, etc. of the hydraulic pump and industrial equipment driven by the hydraulic pump, as well as products of production machines such as injection molding machines and press machines driven by the hydraulic pump. Can improve the yield and the life of the equipment.

  According to the fifth aspect of the present invention, an adaptive identifier that estimates at least the volume of the load connected to the hydraulic pump, and a delay time change that changes the delay time of the delay means based on the output of the adaptive identifier. Therefore, an appropriate delay time can be set according to the volume of the load connected to the hydraulic pump. Therefore, even when a plurality of loads having different volumes are driven by a single hydraulic pump, adjustment of the hydraulic pump control device is facilitated.

  With the hydraulic pump control device described in each of the above claims, the adjustment time at the start-up of the hydraulic pump and the industrial device driven by the hydraulic pump can be shortened. Even if it occurs, it can be easily adjusted at the installation site. Moreover, since the stop time of the industrial apparatus which a hydraulic pump drives can be shortened, productivity of an industrial apparatus improves.

  According to the invention described in claim 6, the rotation of the hydraulic pump is based on the rate of change of the discharge pressure of the hydraulic pump or the generation force of the load connected to the hydraulic pump and the rotational speed of the hydraulic pump. Since the rate of change of the number is calculated, it is possible to provide a control method for the hydraulic pump control device that operates the hydraulic pump at an appropriate rotational speed. Therefore, even when a large volume load is connected, switching from the pressure control state to the flow rate control state can be performed in a short time, the operation cycle of the production machine driven by the hydraulic pump can be shortened, and the productivity is improved. be able to.

  According to the invention described in claim 7, the estimated value of the volume of the load connected to the hydraulic pump is calculated based on the detected value of the discharge pressure or the generated force of the load, and based on the estimated value. Since the delay time is determined, an appropriate delay time can be secured even when the volume of the load is large, and the pressure surge caused by suddenly switching from the pressure control state to the flow control state due to the delay time being too short. Therefore, it is possible to provide a control method for a hydraulic pump control device that operates the hydraulic pump in a stable state.

Embodiments of the present invention will be described below in detail with reference to the drawings.
(First Example)
FIG. 1 is a block diagram of a hydraulic pump control apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a block diagram showing in detail the configuration of a limiting circuit 20 shown in FIG. A hydraulic pump control device 1 shown in FIG. 1 includes a fixed-capacity hydraulic pump 50, pressure detection means 51 that detects the discharge pressure of the hydraulic pump 50, and a rotational speed control that controls the rotational speed of the hydraulic pump 50. Means 40 and a control operation unit 10 that sends a rotational speed command signal IR to the rotational speed control means 40 are provided. The control calculation unit 10 receives the pressure command value Pc and the pressure detection value P by the pressure detection means 51, and outputs a signal (first signal) corresponding to the rotation speed command signal IR. , A load speed command value or a discharge flow rate command value Qc of the hydraulic pump (hereinafter referred to as a flow rate command value Qc in the description of the present embodiment) is input, and a signal (second signal) corresponding to the rotational speed command signal IR ) And a limiting circuit 20 that inputs the first signal and the second signal and outputs the rotational speed command signal IR. Further, the first calculation element 11 includes an integral amplifying unit (digital integrator) 16 for the deviation between the pressure command value Pc and the pressure detection value P, and a zero-order or higher differentiation element (differentiator) 18 of the pressure detection value P. Are configured in a parallel circuit with a feedback amplification unit 19 coupled in parallel. The rotation speed control means 40 includes a servo amplifier 41, a servo motor (AC servo motor) 45, and an encoder (absolute value encoder) 46.

  The rotation shaft of the hydraulic pump 50 is connected to the drive shaft of a servo motor 45 provided in the rotation speed control means 40, and the servo motor 45 is driven by the output current of the servo amplifier 41. The servo motor 45 is attached with an encoder 46 for detecting the rotation angle of the drive shaft. The output signal from the encoder 46 is fed back to the servo amplifier 41, and the rotational speed of the servo motor 45 is detected by the rotational speed detection means 44 provided in the servo amplifier 41. The servo amplifier 41 is based on the output of the comparison control amplification unit 42 and the comparison control amplification unit 42 that amplifies and transforms the deviation signal between the detection signal from the rotation number detection means 44 and the rotation number command signal IR. A rotation speed control circuit 47 composed of a power amplification unit 43 that controls torque (current) and drives the servo motor 45 is provided, whereby the rotation speed of the servo motor 45 (that is, rotation of the hydraulic pump 50) is provided. The number) is controlled so as to be approximately equal to the rotational speed by the rotational speed command signal IR from the control calculation unit 10.

  The discharge line of the hydraulic pump 50 is provided with pressure detection means 51 comprising a semiconductor pressure sensor, and the discharge pressure of the hydraulic pump 50 detected by the pressure detection means 51 is controlled and calculated as a pressure detection signal P. This is fed back to the unit 10. The pressure detection signal P is taken into the control arithmetic unit 10 via the 12-bit analog / digital (A / D) converter 15, and the first arithmetic element 11 and the second arithmetic element are inside the control arithmetic unit 10. 12 and input to the limiting circuit 20, respectively. On the other hand, the pressure command value Pc input to the control calculation unit 10 is input to the first calculation element 11, the second calculation element 12, and the limit circuit 20 via the 12-bit A / D converter 14, and the control calculation value is calculated. The flow rate command value Qc input to the unit 10 is input to the second arithmetic element 12 via the 12-bit A / D converter 13.

The first computing element 11 compares the pressure command value Pc is input and the pressure detection signal P calculates the deviation ΔP of pressure, multiplied by the integral gain K _I, which is pre-programmed to the integral of the deviation ΔP The first differential of the pressure detection signal P is subtracted from the output of the digital integrator 16 that outputs the value obtained by subtracting the output of the proportional device 17 that outputs a value obtained by multiplying the pressure detection signal P by a pre-programmed proportional gain K _P. outputs preprogrammed what the output of the differentiator 18 for outputting a value obtained by multiplying the derivative gain K _D obtained by adding the first signal to. Thus, in this embodiment, the output of the digital integrator 16, the pressure control system by adding the output from the differentiator 18 is a value obtained by multiplying the derivative gain K _D in primary differential pressure detection value P The response time is improved by reducing the time constant, and at the same time, the damping coefficient is set to a large value by subtracting the output from the proportional device 17 that is a value obtained by multiplying the pressure detection value P by the proportional gain K _P. Has improved. On the other hand, if it is desired to increase the time constant, on the other hand, the output of the differentiator 18 may be subtracted from the output of the digital integrator 16, and if the damping coefficient of the pressure control system is too large, the digital The output from the proportional unit 17 may be added to the output from the integrator 16. Further, the output of the limiting circuit 20 is fed back to the first arithmetic element 11, and the output of the first arithmetic element 11 is changed so as to always coincide with the output of the limiting circuit 20.

Second calculation element 12, the flow rate command value Qc, preprogrammed the multiplied value gain K ₁ (correction value) is added to the pressure detection value P, and which further multiplied by a gain K ₂ to this value the 2 as a signal. Here, the gain K ₁ which is pre-programmed, the pressure detection signal P, is smaller than a value obtained by subtracting a pre-programmed value Pw from the pressure command value Pc, that is, when a P <(Pc-Pw) is Constant when the pressure detection signal P is equal to or greater than the value obtained by subtracting the pre-programmed value Pw from the pressure command value Pc, that is, P> (Pc−Pw). This is a nonlinear gain. The gain K ₁ by non-linear gain, it is possible to set the pressure-flow rate characteristic of the hydraulic pump 50 as desired. The gain K ₂ is a gain for converting the input value into a value corresponding to the rotation speed command signal IR input to the servo amplifier 41 with reference to the discharge amount per rotation of the hydraulic pump 50.

Here, the pressures of the hydraulic pump control device 1 according to the embodiment of the present invention shown in FIG. 1, the conventional hydraulic pump control device 100 shown in FIG. 6, and the conventional hydraulic pump control device 110 shown in FIG. -Flow characteristics are shown in Fig. 3. 3, the pressure-flow rate characteristic when the above-described nonlinear gain K ₁ is used in the hydraulic pump control device 1 is shown by a solid line, and the pressure-flow rate characteristic of the conventional hydraulic pump control device 100 shown in FIG. 6 is shown. Is indicated by a one-dot chain line, and a pressure-flow rate characteristic of the conventional hydraulic pump control device 110 shown in FIG. 7 is indicated by a broken line. In the hydraulic pump control device 1, when the discharge pressure (pressure detection value) P of the hydraulic pump 50 is P <(Pc−Pw), the flow rate control state is set, and the output of the second computing element 12 is the first. Since the signal No. 2 is effective, when the discharge pressure P changes, the rotational speed command signal IR increases by an amount corresponding to the pump leakage coefficient. Therefore, regardless of the discharge pressure P, the discharge flow rate Q is a constant flow rate that matches the flow rate command value Qc. When the discharge pressure P is (Pc−Wp)>P> (Pc−Pw), the flow rate control state is maintained, but the rotation speed command signal IR maintains a constant value regardless of the discharge pressure P. As the discharge pressure P increases, the discharge flow rate Q of the hydraulic pump 50 has a characteristic of decreasing by an amount corresponding to the leakage flow rate. When the discharge pressure P further increases and the discharge pressure P becomes slightly lower than the pressure command value Pc, the first signal falls below the second signal and the flow control state is switched to the pressure control state. When switched to the pressure control state, the discharge flow rate Q of the hydraulic pump 50 decreases rapidly. Since the hydraulic pump control device 1 can set a high gain, it is possible to reduce the difference (Wp in FIG. 3) between the pressure command value Pc and the discharge pressure P that switches to the pressure control state, which is extremely steep. Therefore, it is possible to obtain a low discharge flow rate Q reduction characteristic.

  On the other hand, in the case of the conventional control device 100 and the conventional control device 110, the rotational speeds of the hydraulic pumps 106 and 117 are only kept constant with respect to a constant rotational speed command value IR. Even if the discharge pressure P increases, the discharge flow rate Q gradually decreases by an amount corresponding to the leakage flow rate of the hydraulic pumps 106 and 117. Further, neither the control device 100 nor the control device 110 can obtain a steep reduction characteristic of the discharge flow rate Q as compared with the hydraulic pump control device 1 according to the present invention when the pressure control state is entered. .

The hydraulic pump control device 1 uses a nonlinear gain K ₁ (correction value) as a characteristic in the flow rate control state. However, as described above, the correction value characteristic can be arbitrarily set according to the intended application. For example, it can be set to have a characteristic of Q = Qc−kP, that is, a characteristic that the discharge flow rate Q decreases with a certain inclination as the discharge pressure P increases. Here, k is a gain indicating an arbitrary inclination. When it is desired to simulate the characteristics of the conventional hydraulic pump control device, not only the characteristics of the first calculation element 11 that governs the characteristics of the pressure control system but also the nonlinear gain as described above is used. Thus, it can be realized to some extent by adjusting the characteristics of the second arithmetic element 12.

ただし〔数８〕では簡単のため、第１の演算要素１１のフィードバック増幅部１９に零次の微分要素１８のみを用いた場合を示している。 The characteristics of the first computing element 11 and the second computing element 12 are as follows. The output (first signal) of the first computing element 11 is n _p , and the output (second signal) of the second computing element 12 is n _q , the sampling period is T, and the value at the i-th sampling time is represented by [i], and the first signal n _p [i] and the second signal n _q [i] are It can be easily realized by performing a digital operation as expressed by [Equation 8] and [Equation 9].

However, [Equation 8] shows a case where only the zero-order differential element 18 is used for the feedback amplification unit 19 of the first calculation element 11 for simplicity.

  Next, FIG. 2 shows a block diagram showing the configuration of the limiting circuit 20 in detail. As shown in the figure, the limiting circuit 20 includes a two-stage selection circuit including a first selection circuit 21 and a second selection circuit 22, a pressure detection value P, a rate of change of the pressure detection value P, and a limitation circuit 20. An adaptive identifier 24 for estimating the volume of the load connected to the hydraulic pump 50 from the output (rotation speed command signal IR), a change rate limiter (change rate) for setting the change rate of the first signal and the second signal Setting means) 23, a switching detector (switching detecting means) 26 for detecting a change in the pressure command value Pc, and a first signal during a delay time after switching of the pressure command value Pc detected by the switching detector 26. The delay time of the time limit delay recovery timer 25 is changed based on the output of the variable time delay return timer (delay means) 25 and the adaptive identifier 24 that changes the second signal and the second signal at the rate of change set by the change rate limiter 23. Changing delay time Stage 28 is configured by a change rate adjusting means 29 for changing the change rate of the change rate limiter 23 based on the output of the adaptive identifier 24. The result of the limiting process performed by the limiting circuit 20 is output as a rotational speed command signal IR via a 12-bit digital / analog (D / A) converter 27.

In the first selection circuit 21, the first signal n _p [i] and the second signal n _q [i] are compared, and when the second signal n _q [i] is small (that is, n _p [i] ]> N _q [i]), the second signal n _q [i] is selected. The output of the first selection circuit 21 is fed back to the first arithmetic element 11 and the first signal is changed so as to coincide with the second signal.
That is, when the output of the first selection circuit 21 is n ₁ [i], the following processing is performed.

As described above, until the difference between the pressure command value Pc and the actual discharge pressure P becomes a slight value, approximately n _p [i] <n _q [i]. The signal n _q [i] is output preferentially. In [Equation 11], it appears that the first signal is limited regardless of the selection, but when the first signal n _p [i] is selected by the first selection circuit 21, n _{Since 1} [i] and _np [i] have the same value, the first signal _np [i] is substantially only when the second signal _nq [i] is selected. That is, the second signal n _q [i] is limited to coincide with it. Since the first signal n _p [i] is used for the calculation at the next sampling time of the first signal n _p [i], it is adjusted so that the integrated amount of the deviation is not excessively equivalent. It will be. For this reason, when the deviation is large (that is, in the case of flow rate control), it is possible to prevent a so-called windup phenomenon in which the integral amount becomes excessive and overshoot becomes large or unstable. Therefore, the hydraulic pump control device 1 according to the present invention is greatly different from the conventional hydraulic pump control device shown in Patent Document 2 in that the hydraulic pump control device 1 is not PID controlled and is integrated and amplified. For example, it is not necessary to obtain the value of the integral term of the unit 16, whereby the pressure control of the hydraulic pump 50 can be easily performed, and the operability of the hydraulic pump control device 1 is improved.

  The second selection circuit 22 is configured to operate only when the pressure command value Pc is changed abruptly, for example, when it is increased stepwise. The pressure command value Pc is input to a switching detector 26 having a Schmitt trigger gate 26a having an appropriate hysteresis and a differentiation circuit 26b, and the switching of the pressure command value Pc is detected as a pulse signal, and its output is delayed by delay means. It is held by a certain variable type time-delay return timer 25. For this reason, when the pressure command value Pc is changed at a low speed, switching is not detected and the output of the first selection circuit 21 is output as it is, but when the pressure command value Pc is switched stepwise. The second selection circuit 22 operates to limit the change rate.

ここで、ｋ_１は推定の収束速度を決定する｜ｋ_１｜＜１なる任意のパラメータであり、遅延時間には、推定の収束速度を見込んで一定の下限が与えられている。また、実際の負荷が、容積だけでなくシリンダが運動するような場合には圧力が上昇しないためにｖ＾〔ｉ〕が過大な値になってしまうが、この場合にも適切な遅延時間で打ち切られるように上限が設けられている。負荷の容積の推定値ｖ＾〔ｉ〕は、流量制御状態に切り換わるごとに最小の容積に相当する予めプログラムされた初期値に初期化される。 The holding time (delay time) by the time delay return timer 25 is determined based on the output of the adaptive identifier 24. Here, the adaptive identifier 24 calculates [Expression 12] from the pressure P [i], the pressure change rate ΔP = P [i] −P [i−1], and the output n _C [i] of the limiting circuit. A value obtained by using the estimated value v ^ [i] of the volume of the load connected to the hydraulic pump 50 is output.

Here, k ₁ is an arbitrary parameter of | k ₁ | <1 that determines the convergence speed of the estimation, and the delay time is given a certain lower limit in consideration of the convergence speed of the estimation. In addition, when the actual load is not only the volume but also the cylinder moves, the pressure does not increase and v ^ [i] becomes an excessive value. In this case as well, an appropriate delay time is used. There is an upper limit to be censored. The estimated volume v ^ [i] of the load is initialized to a preprogrammed initial value corresponding to the minimum volume every time the flow control state is switched.

On the other hand, the output of the adaptive identifier 24 is also input to the change rate limiter 23 via the change rate adjusting means 29, and changes that adjust the change rate of the output of the limiting circuit 20 when the pressure command value Pc is switched. It is also used to adjust the variable gain K _R of the rate limiter 23. Variable gain K _R is not changed when the estimated value v ^ [i] of the volume is small, the rate of change is increased when the estimated value of the volume v ^ [i] is large. The variable gain K _R, for the same reason as the delay time of the time limit delay return timer 25, a fixed upper limit is set close to 1. In the present embodiment, the volume of the load is estimated from the rate of change of the pressure detection value P and the output of the limiting circuit 20 (the rotational speed command signal IR), and the variable gain K of the rate of change limiter 23 is based on the output. _R is adjusted, but when the rate of change of the detected pressure value P is small or when the output of the limiting circuit 20 is large, a large gain is obtained. There when large may determine the value of the variable gain K _R of the change rate limiter 23 using another calculation formula such that a small gain.

なる演算式で計算される。 Meanwhile, the change rate limiter 23, a value obtained by multiplying the variable gain K _R to the difference between the outputs of one sample before the limiting circuit 20 of the first selection circuit 21, added to the output of one sample before the limiting circuit 20 It is supposed to be. The output of a specific limiting circuit 20, the variable gain value of K _R of the rate of change limiter _23, when the delay time is T _D,

It is calculated by the following equation.

If the above variable gain K _R is a value close to 1, the output of the limiter 20 is substantially coincident with the output of the first selection circuit 21. Further, when the value of the variable gain K _R is a small value close to 0, the output of the limiting circuit 20 is a value very close to the output of the previous sample. Since the time during which the change rate limiter 23 operates is a certain period (delay time) after the pressure command value Pc changes suddenly, the output of the first selection circuit 21 normally has a second value corresponding to the flow rate command value Qc. It becomes approximately equal to the output of the calculation element 12. As described above, the flow rate control state is substantially changed even during the delay time, so that even if the delay time elapses and the flow rate control state is entered, there is no sudden change in the flow rate. By such an operation of the rate of change limiter 23, a stable switching with little substantial operation delay can be realized even in a step-like switching from the pressure control state to the flow rate control state. On the other hand, when the flow rate does not flow to the load, the pressure detection value P rises and the adaptive identifier 24 outputs a small value, so the rate of change becomes small and the occurrence of surge pressure is suppressed, and the pump discharge pressure P Can quickly return to the pressure control state when the pressure command value Pc is reached.

  As described above, the hydraulic pump control device 1 according to the embodiment of the present invention is configured to obtain good control characteristics by simple control calculation and selection. The calculation formula is an example, and the calculation method such as the adaptive identifier 24 and the change rate limiter 23 may be any calculation method as long as appropriate estimation and change rate limitation are possible. For example, the adaptive identifier 24 of [Equation 12] is configured to estimate only the load volume, but other element variables (for example, load speed) incorporated in the hydraulic pump control device 1. If it is configured to be able to estimate an equivalent bulk modulus or a ratio between the volume of the load and the bulk modulus, etc., the more accurate control can be realized.

  Further, in the hydraulic pump control device 1 according to the embodiment of the present invention, good pressure control and flow rate control can be realized using the fixed displacement type hydraulic pump 50, so that a high-class control device or a complicated structure can be realized. Without using a variable displacement pump, a hydraulic pump and a hydraulic pump control device excellent in energy saving can be provided at low cost.

(Second embodiment)
Next, FIG. 4 shows an embodiment in which the hydraulic pump control device 1 is attached to a plastic raw material injection molding machine 78. An injection molding machine 78 shown in FIG. 4 heats and melts a plastic raw material, injects it into a mold at a high temperature and solidifies it by cooling to produce a plastic product. A metering motor 60 which is a fixed capacity type axial piston motor. An injection cylinder 61, a mold clamping cylinder 71, and a mold 67 including a moving mold 67a and a fixed mold 67b. The injection molding machine 78 includes a hydraulic pump control device 1 according to the present invention that includes a hydraulic pump 50 that drives the injection molding machine 78, a pressure command value Pc, a flow rate command value Qc, and an electromagnetic valve. An injection molding machine controller 76 for sending the operation signal is attached. In FIG. 4, the configurations of the injection molding machine 78 and the hydraulic pump control device 1 are simplified. One cycle of the injection molding process by the injection molding machine 78 will be described in detail below.

[Mold closing process]
First, the injection molding machine controller 76 opens the flow path connected to the rear end portion 71b of the clamping cylinder 71 by driving the solenoid 73b on the left side of the solenoid valve 73, and the flow rate command value Qc with a large flow rate and the high pressure flow rate. Pressure command value Pc is given. As a result, the mold clamping cylinder 71 is advanced, and the movable die plate 69 guided by the diver 70 and the movable mold 67a attached to the movable die plate 69 are moved to the fixed mold 67b side. Close. At this time, since no load is actually applied, the control state of the hydraulic pump control device 1 becomes the flow control state, and a large flow rate is discharged from the hydraulic pump 50, so that the moving mold 67a moves at high speed. To do.

  When the injection molding machine controller 76 detects that the movable mold 67a has reached a predetermined position (a position before the closing), pressure is applied in order to avoid biting of foreign matter into the mold 67 and damage to the mold 67. Both the command value Pc and the flow rate command value Qc are set to small values. For this reason, the moving mold 67a is decelerated just before it is closed, and when a foreign object is caught in the mold 67, the hydraulic pump control device 1 shifts to a low pressure control state. Stop before contacting the fixed mold 67b. Here, the injection molding machine controller 76 detects the contact of the mold 67 with a proximity switch (not shown), and detects an abnormal state when the movable mold 67a does not contact the fixed mold 67b after a predetermined time has elapsed.

  Even when the moving mold 67a comes into contact with the fixed mold 67b without foreign matter getting caught in the mold 67, the pressure control state is shifted to a low pressure, but when the injection molding machine controller 76 detects the contact of the mold 67, A large pressure command value Pc and a flow rate command value Qc are given in order to apply a prescribed pressure to the mold 67. At this time, since the pressure command value Pc increases stepwise, the limiting circuit 20 detects this, and the change rate limiter 23 (see FIG. 2) acts. Since the volume of the clamping cylinder 71 is extremely large (large output), the rotational speed change rate of the hydraulic pump 50 is compared by the adaptive identifier 24 (see FIG. 2) and the change rate adjusting means 29 (see FIG. 2). The pressure of the clamping cylinder 71 rises quickly. When the pressure of the mold clamping cylinder 71 approaches a predetermined applied pressure, the control state of the hydraulic pump 50 switches to the pressure control state, and the rotational speed of the hydraulic pump 50 is an appropriate value for maintaining the necessary pressure (comparison). Low rotation speed). Then, in a state where a high pressure is applied to the mold clamping cylinder 71, the solenoid 73 b of the electromagnetic valve 73 is demagnetized, and the mold clamping process is completed while maintaining the pressure of the mold 67.

  Since the clamping cylinder 71 has an extremely large output, there is a risk that if a surge with a large pressure occurs when the mold 67 is pressurized, the mold 67 may be damaged or a large vibration or noise may occur. However, in the hydraulic pump control device 1, since a rapid change in the rotational speed of the hydraulic pump 50 is suppressed by the function of the change rate limiter 23, a large pressure surge does not occur. In addition, if the rate of change of the rotational speed is fixed to a small value in order to suppress the occurrence of pressure surge, it takes a long time to increase the pressure, which impairs productivity. In 1, an appropriate change rate is set by the functions of the adaptive identifier 24 and the change rate adjusting means 29, so that a rapid pressure increase can be obtained.

[Injection process]
When the mold clamping process is completed, the process proceeds to the injection process. At the tip of the injection screw 62, a melt-kneaded raw material resin (plastic resin) previously measured in a predetermined amount by a measuring step described below is stored, and this resin is rapidly molded by moving the injection cylinder 61 forward. 67 is injected. In the injection process, one solenoid 74 a of the electromagnetic valve 74 is excited, and the liquid discharged from the hydraulic pump 50 is guided to the rear end portion of the injection cylinder 61. At the start of injection, the hydraulic pump control device 1 gives a flow command value Qc corresponding to a high injection speed and a pressure command value Pc corresponding to an appropriate limit pressure. In this case, since the resistance to the injection is only the resistance that the resin passes through the thin nozzle of the mold 67, the load is small. Accordingly, the hydraulic pump control device 1 enters the flow rate control state, and the hydraulic pump 50 discharges a constant flow rate, so that the injection cylinder 61 starts moving forward at a substantially constant speed. As resin fills the mold 67, the resistance to injection increases and the driving force (pressing force) required for the injection cylinder 61 also increases, but reaches the vicinity of the limit pressure given by the pressure command value Pc. Until then, the speed of the injection cylinder 61 is maintained.

  When the filling of the resin proceeds and the resin reaches a narrow portion in the mold 67 and the resistance to injection increases, the load pressure increases depending on the flow state of the resin and approaches the limit pressure. In such a case, if an excessive pressure is generated or the speed of the injection cylinder 61 is rapidly changed, the resin in the mold 67 is not uniformly filled. Therefore, as shown in FIG. 3, the hydraulic pump control device 1 gradually decreases the discharge flow rate Q of the hydraulic pump as the pressure rises by making the rotational speed of the hydraulic pump 50 constant when approaching the limit pressure. Generation of excessive pressure is prevented, and when the pressure further increases, the pressure shifts to a pressure control state to prevent the pressure from becoming excessive. At this time, since the injection cylinder 61 continues to advance while reducing its speed, the filling of the resin into the mold 67 proceeds. Then, although the load pressure of the injection cylinder 61 changes depending on the flow state of the resin in the mold 67, the change state of the load pressure varies depending on the shape and size of the mold 67. When the load pressure decreases, the speed of the injection cylinder 61 returns to the original speed, and when the load pressure increases, the pressure control state is controlled to control the limit pressure. As described above, in the first half of the injection process, there may be a state in which the pressure control state and the flow rate control state are shifted to each other. However, in the hydraulic pump control device 1, the flow rate control state and the pressure are changed. Since stable switching between the control state and the both is realized, the resin is uniformly filled.

  When the injection cylinder 61 reaches a specified position, the injection molding machine controller 76 increases the pressure command value Pc to the pressure at the completion of injection. As a result, the control state of the hydraulic pump control device 1 becomes the flow rate control state, and the resin is completely filled in the mold 67. When the resin 67 is filled with the resin 67, the pressure of the injection cylinder 61 increases, and at this time, the pressure control state is switched. For this reason, when the pressure control state is reached when the specified position is reached (that is, when the pressure command value Pc is increased to the pressure at the completion of injection), the pressure command value Pc of the pressure control is changed. A step-like increase occurs. If a pressure surge occurs at this time, the flow of the resin becomes unstable, and a good molded product cannot be obtained. However, in the hydraulic pump control device 1, it is more appropriate for the functions of the adaptive identifier 24 and the change rate adjusting means 29. Since the rate of change is set, it is possible to smoothly shift to the flow rate control state while preventing the occurrence of a pressure surge. Further, when the resin is filled in the mold 67, the area on the moving mold 67a side (that is, the area on the clamping cylinder 71 side) is larger than the area of the nozzle portion 65 on the injection screw 62 side. If the pressure of the mold is not properly limited, the output of the clamping cylinder 71 is insufficient and a gap is formed between the molds 67 to cause burrs in the molded product. Therefore, the occurrence of this burr can be avoided.

  When the back pressure of the injection cylinder 61 exceeds a predetermined value and it is detected that the injection screw 62 has reached the position at the completion of injection and the completion of injection of the resin is detected, the injection molding machine controller 76 controls the electromagnetic valve 74. Demagnetize and set both the pressure command value Pc and the flow rate command value Qc to zero. And the plastic product (molded article) is shape | molded by cooling the metal mold | die 67 and cooling and solidifying the resin inside. During the cooling time for cooling the mold 67, the raw material resin injected in the next cycle is measured.

[Weighing process]
In the measuring step, the plastic material (raw material resin) introduced from the hopper 72 is fed into the heating cylinder 63 heated by the band heater 64 by the rotation of the measuring motor 60 and melted at the tip of the injection screw 62. As the resin is filled, the injection screw 62 moves backward, and the volume of the melted raw material resin is measured by the amount of the backward movement. At this time, the hydraulic pressure pump control apparatus 1 has a flow rate command value Qc for rotating the metering motor 60 at an appropriate number of revolutions from the injection molding machine controller 76 and a load pressure for rotating the metering motor 60. An appropriate pressure command value Pc and an excitation signal Px for exciting the solenoid valve 75 are provided. For this reason, the hydraulic pump 50 discharges a constant flow rate regardless of the load pressure, and the metering motor 60 rotates at the above-described constant rotational speed. When the volume of the raw material resin reaches a specified value, the injection molding machine controller 76 demagnetizes the electromagnetic valve 75 and sets both the flow command value Qc and the pressure command value Pc to zero, thereby stopping the metering motor 60.

[Mold opening process]
After the weighing process is completed, the mold 67 is opened and the cooled molded product is taken out. In this mold opening process, the solenoid coil 73a on the right side of the electromagnetic valve 73 is excited to open the flow path connected to the rod side 71a (mold 67 side) of the mold clamping cylinder 71. In the first stage of the mold opening process, it is necessary to open at a low speed with a large pressure so as not to damage the surface of the molded product when the resin is peeled off from the mold 67. Therefore, the pressure command value Pc of a high pressure is small. A flow rate command value Qc is given. Therefore, a high load is applied while the resin is stuck to the mold 67, and in some cases, a pressure control state is established. When the resin is peeled off from the mold 67, the load is reduced and the flow shifts to the flow control state. The mold 67 is opened at a high speed by giving a large flow command value Qc after a predetermined time has elapsed (that is, after the resin has been peeled off from the mold 67), and the small flow command value Qc is again set before the stop position. Stop after giving and decelerating. As described above, in the mold opening process, multistage speed control is performed in which the mold clamping cylinder 71 is changed from the low-speed movement state to the high-speed movement state, and then is again moved to the low-speed movement state, but a sufficiently high pressure command value Pc is given. Therefore, while the mold clamping cylinder 71 is moving, the discharge flow rate Q of the hydraulic pump 50 follows the flow rate command value Qc.

  When the mold opening process is finished, the molded product is pushed out from the mold 67 by an ejector cylinder (not shown) and taken out. By taking out the molded product, the operation of one cycle is completed, and then the next molded product manufacturing cycle is started using the raw material resin that has already been weighed in the above weighing process, and the procedure from the above clamping process Is executed.

  As described above, in the injection molding machine 78, switching between the pressure control state and the flow rate control state is performed very frequently, and the load to be driven varies variously from large to small. By using the hydraulic pump control device 1, good control characteristics can be obtained even when the control state is switched, and switching from the pressure control state to the flow rate control state can be performed in a short time. It can be driven appropriately.

(Third embodiment)
Next, FIG. 5 shows an embodiment in which the hydraulic pump control device 1 is attached to a molding device 79 for forming a resin film on a semiconductor wafer. A molding apparatus 79 shown in FIG. 5 includes a movable surface plate 82 that moves up and down between a lower surface plate 80 and an upper surface plate 81, and an upper mold 86 a and a movable surface plate 82 attached to the lower surface of the upper surface plate 81. The lower mold 86b attached to the upper surface of the metal mold 86 constitutes the mold 86. The movable surface plate 82 is moved up and down by the lift cylinder 85, and the lower mold 86 b is moved up and down by the main cylinder 84. The generated force of the lift cylinder 85 and the main cylinder 84, which are loads of the hydraulic pump 50, is detected by the output of the strain gauge 90 installed on the diver 83 of the molding device 79, and this detected value is sent to the hydraulic pump control device 1. Feedback has been provided. In the actual molding apparatus, the lift cylinders 85 are installed on both sides of the main cylinder 84. However, for convenience of illustration, only one lift cylinder 85 is shown in FIG. Only one of the pipes is shown. The one-cycle molding process by the molding device 79 will be described in detail below.

[High-speed mold feeding process]
A semiconductor wafer W is placed in a cavity 87 between the upper mold 86a and the lower mold 86b by a transfer device (not shown), and a cylindrical resin pellet Pt is placed on the semiconductor wafer W. When the transfer device is retracted from between the molds 86, the molding device controller 98 causes the hydraulic pump control device 1 to prevent the speed command value Sc for driving the lift cylinder 85 and the foreign matter from being caught in the molds 86. A force command value Wc corresponding to the limit force signal is given, and at the same time, the solenoid 91a on the right side of the solenoid valve 91 is excited. At this time, the large-capacity main cylinder 84 is filled with the working fluid in the tank 97 via the prefill valve 95.

  When the lift cylinder 85 rises, the movable surface plate 82 and the lower mold 86b attached to the upper surface thereof rise and approach the upper mold 86a. When it is detected by the output of the displacement sensor 89 that the upper mold 86a and the lower mold 86b approach each other and approach a predetermined position, the molding apparatus controller 98 sends a speed command value Sc to the hydraulic pump control apparatus 1. When the lower mold 86b reaches a predetermined position, the solenoid 91a of the solenoid valve 91 is demagnetized, the lift cylinder 85 is stopped, and at the same time, the speed command value Sc is set to zero and the hydraulic pump 50 Stop. At this time, if a foreign object is caught between the upper mold 86a and the lower mold 86b, the output of the strain gauge 90 reaches the force command value Wc before the lower mold 86b reaches a predetermined position. The force control state is entered. Then, the lift of the lift cylinder 85 is stopped by the biting of the foreign matter, and the molding apparatus controller 98 detects an abnormality when the lower mold 86b does not reach a predetermined position within a specified time.

  When no foreign matter is caught, when the lower mold 86b reaches a predetermined position, the upper mold 86a and the resin pellet Pt are not yet in contact with each other. Here, the upper and lower molds 86 are heated by a built-in heater (not shown), and the resin pellets Pt are preheated by the ambient temperature between the adjacent molds 86. After the resin pellet Pt is sufficiently preheated by waiting for a certain time in this state, the molding apparatus controller 98 outputs a low speed command value Sc and a force command value Wc corresponding to the limit force of the foreign object biting. At the same time as the hydraulic pump 50 is driven, the solenoid 92b on the left side of the solenoid valve 92 and the solenoid of the solenoid valve 93 are excited. As a result, the main cylinder 84 starts to rise at a low speed, and the working fluid in the lift cylinder 85 is supplied and discharged from the tank 97 via the electromagnetic valve 93. At this time, when a foreign object is caught between the upper mold 86a and the lower mold 86b, the output of the strain gauge 90 is the force command value before the lower mold 86b reaches a predetermined position as described above. The force control state is reached when Wc is reached. Then, ascending of the foreign matter stops the main cylinder 84 from rising, and the molding apparatus controller 98 detects an abnormality when the position of the lower mold 86b does not reach a predetermined position within a specified time.

[Clamping process]
When no foreign matter is bitten and the upper mold 86a and the lower mold 86b come close to each other and the resin pellet Pt reaches a position just before contacting the upper mold 86a, the molding apparatus controller 98 receives the speed command value. Sc is increased in speed, and the force command value Wc is switched to a force command value corresponding to mold clamping. As a result, the main cylinder 84 starts to rise at high speed, and the resin pellets Pt come into contact with the upper mold 86a and are crushed to spread on the semiconductor wafer W. When the resin pellet Pt comes into contact with the upper mold 86a, a compression reaction force acts, and the generated force is detected by the strain gauge 90 of the diver 83. Since the detected generated force is fed back to the hydraulic pump control device 1, the speed of the main cylinder 84 is corrected by the force detection value and kept at the set speed. When the resin pellets Pt sufficiently advance on the semiconductor wafer W, the outer diameter of the resin pellets Pt increases, so that the progress rate of the resin pellets Pt increases and at the same time the compression reaction force increases. The molding apparatus controller 98 has a speed at which the outer diameter of the resin pellet Pt increases (resin progress speed) based on the distance between the upper mold 86a and the lower mold 86b in order to keep the flow state of the resin pellet Pt good. The speed command value Sc is gradually decreased so as to be substantially constant. At this time as well, the rotational speed of the hydraulic pump 50 is corrected by the force detection value, so that the rising speed of the main cylinder 84 is the speed command value Sc. Follow the set speed by.

  When the resin pellet Pt is sufficiently extended on the semiconductor wafer W and the resin is filled in the cavity 87 between the upper mold 86a and the lower mold 86b, the upper mold 86a and the lower mold 86b come into contact with each other. Thus, the generated force detected from the diver 83 increases rapidly. Accordingly, the control state by the hydraulic pump control device 1 shifts to the force control state, and the generated force of the main cylinder 84 is controlled to the set force. At this time, if the transition from the speed control state to the force control state is not smoothly performed, the die 86 is damaged or a large vibration / noise is generated due to a large generated force by the large-capacity main cylinder 84. There is danger. However, according to the control by the hydraulic pump control device 1, since a smooth transition from the speed control state to the force control normal state can be realized, such a problem does not occur.

[Pressure release process]
When the generated force of the main cylinder 84 reaches a specified value, the hydraulic pump control device 1 informs the molding device controller 98 that the generated force of the main cylinder 84 has reached the specified force via a signal path (not shown). It is transmitted as a force control completion signal. The molding device controller 98 detects the completion of the mold clamping process by receiving a force control completion signal for connection for a preset time, and demagnetizes the solenoids of the solenoid valve 92 and the solenoid valve 93 to maintain the generated force. To do. Further, the hydraulic pump control device 1 is given zero as the speed command value Sc, and the hydraulic pump 50 stops. The resin pellets Pt extended on the semiconductor wafer W are heated and cured by a heater built in the mold 86 to form a resin layer that covers the semiconductor wafer W.

  In this state, it waits for a preset holding time (cure time) to elapse. The length of this cure time varies depending on the type of resin used. After the cure time elapses, the molding device controller 98 excites the solenoid 92a on the right side of the solenoid valve 92, so that the compressed fluid in the main cylinder 84 is discharged through the restrictor 96 so that the mold 86 can be discharged. However, since the mold 86 is supported by the left and right lift cylinders 85, it hardly moves.

[Mold opening process]
After the depressurization step, the molding device controller 98 gives the hydraulic pressure control value 1 corresponding to the speed for lowering the upper mold 86a and the force command value Wc corresponding to the maximum mold opening force to the hydraulic pump control device 1. The hydraulic pump 50 is driven, and at the same time, the solenoid 91b on the left side of the solenoid valve 91 and the solenoid of the solenoid valve 94 are excited. Thereby, when the lift cylinder 85 descends, the movable surface plate 82 and the lower mold 86b start to descend, the lower mold 86b is separated from the upper mold 86a, and the resin is peeled off from the upper mold 86a. The working fluid in the main cylinder 84 is discharged to the tank 97 through the prefill valve 95 that is forcibly opened by the electromagnetic valve 94. At this time, if an excessive mold opening force is applied, the semiconductor wafer W coated with the resin is damaged, but the generated force of the lift cylinder 85 is within a range in which the semiconductor wafer W is not damaged by the hydraulic pump controller 1. Limited. When the resin is peeled off from the upper mold 86a, no external force is applied to the mold 86, and the lower mold 86b thereafter descends at a speed given by the speed command value Sc. When the displacement sensor 89 detects that the mold 86 has sufficiently opened and the lower mold 86b has approached a predetermined position, the molding device controller 98 reduces the speed command value Sc, so that the lower mold 86b is in the predetermined position. When the position is reached, the solenoid valve 91 is demagnetized and the lift cylinder 85 is stopped. At the same time, zero is output to the hydraulic pump control device 1 as the speed command value Sc and the hydraulic pump 50 is stopped.

  When the mold 86 is stopped, a transfer device (not shown) takes out the coated semiconductor wafer W on the mold 86. Thus, one molding process is completed.

  As described above, in the molding apparatus 79, it is necessary to accurately control the pressure applied to the mold 86 and the resin extension speed when the resin is compression-molded on the semiconductor wafer W. Although it is necessary to shift quickly and smoothly to the control state, these requirements can be easily realized by the control by the hydraulic pump control device 1.

  In each of the above-described embodiments, control of the hydraulic pump is shown by way of example of control by a combination of the discharge pressure command and discharge flow rate command of the hydraulic pump device, or control by a combination of the speed command and force command of the load device. However, the control of the hydraulic pump may be realized by a combination of a load speed command and a pressure command of the hydraulic pump device, or another combination of a flow rate command and a load force command of the hydraulic pump device.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims and the technical idea described in the specification and drawings. Deformation is possible. It should be noted that any shape, structure, and material not directly described in the specification and drawings are within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited.

It is a block diagram which shows the structure of the hydraulic pump control apparatus 1 concerning this invention. 3 is a block diagram showing a configuration of a limiting circuit 20. FIG. It is a figure which shows the pump discharge pressure-flow rate characteristic of the hydraulic pump control apparatus 1, the conventional hydraulic pump control apparatus 100, and the conventional hydraulic pump control apparatus 110 concerning this invention. It is a figure which shows schematic structure of the injection molding machine 78 which attached the hydraulic pump control apparatus 1 concerning this invention. It is a figure which shows schematic structure of the molding apparatus 79 which attached the hydraulic pump control apparatus 1 concerning this invention. It is a block diagram which shows the structure of the conventional hydraulic pump control apparatus 100. It is a block diagram which shows the structure of the conventional hydraulic pump control apparatus 110. It is a block diagram which shows the structure of the conventional hydraulic pump control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic pump control apparatus 10 Control calculating part 11 1st calculating element 12 2nd calculating element 13 A / D converter 14 A / D converter 15 A / D converter 16 Integration amplification part (digital integrator)
17 Proportional device 18 Differentiator 19 Feedback amplification unit 20 Limit circuit 21 First selection circuit 22 Second selection circuit 23 Change rate limiter (change rate setting means)
24 Adaptive identifier 25 Time delay return timer (delay means)
26 Switching detector (switching detection means)
27 D / A converter 28 Delay time changing means 29 Change rate adjusting means 40 Rotation speed control means 41 Servo amplifier 42 Comparison control amplification section 43 Power amplification section 44 Rotation speed detection means 45 Servo motor (AC servo motor)
46 Encoder (Absolute encoder)
47 Rotational speed control circuit 50 Hydraulic pump 51 Pressure detection means 60 Metering motor 61 Injection cylinder 62 Injection screw 63 Heating cylinder 64 Band heater 65 Nozzle part 67 Mold 69 Moving die plate 70 Diver 71 Clamping cylinder 72 Hopper 73 Solenoid valve 74 Electromagnetic valve 75 Electromagnetic valve 76 Injection molding machine controller 78 Injection molding machine 79 Molding device 80 Lower surface plate 81 Upper surface plate 82 Movable surface plate 83 Diver 84 Main cylinder 85 Lift cylinder 86 Mold 87 Cavity 89 Displacement sensor 90 Gauge 91 Electromagnetic valve 92 Solenoid valve 93 Solenoid valve 94 Solenoid valve 95 Prefill valve 97 Tank 98 Molding device controller I Rotational speed detection signal IR Rotational speed command signal P Pump discharge pressure Pc Pressure command value Q Pump discharge flow rate Qc Flow rate command value Sc Speed command value c force command value

Claims (7)

A hydraulic pump; rotational speed control means for controlling the rotational speed of the hydraulic pump to match the rotational speed command signal; pressure detection means for detecting a discharge pressure of the hydraulic pump; and the rotational speed command signal A hydraulic pressure pump discharge pressure and a hydraulic pump discharge flow rate, or a hydraulic pump discharge pressure and a speed of a load connected to the hydraulic pump. A hydraulic pump control device comprising:
The control calculation unit includes a first calculation element that outputs a signal corresponding to a rotation speed command signal input to the rotation speed control unit from a detected value of the discharge pressure by the pressure detection unit and a changeable pressure command value. A signal corresponding to the rotation speed command signal input to the rotation speed control means is output from the load speed command value or the discharge flow rate command value of the hydraulic pump with reference to the discharge amount per rotation of the hydraulic pump. A second calculation element, and a limiting circuit that limits the output of the first calculation element with the output of the second calculation element and outputs a rotation speed command signal;
The first calculation element is a parallel combination of an integral amplifying unit for deviation between the discharge pressure detection value and the discharge pressure command value and a feedback amplifying unit in which differential elements of zero or higher order of the discharge pressure detection value itself are coupled in parallel. A hydraulic pump control device comprising a circuit. A hydraulic pump, a rotational speed control means for controlling the rotational speed of the hydraulic pump to coincide with the rotational speed command signal, a force detection means for detecting a generated force of a load connected to the hydraulic pump, A load generating force connected to the hydraulic pump and a discharge flow rate of the hydraulic pump, or a load generating force connected to the hydraulic pump, comprising a control calculation unit that outputs the rotation speed command signal A hydraulic pump control device for controlling the speed of a load connected to the hydraulic pump,
The control calculation unit outputs a signal corresponding to a rotation speed command signal input to the rotation speed control means from a detected value of load generation force by the force detection means and a changeable force command value. A signal corresponding to a rotational speed command signal input to the rotational speed control means with reference to the discharge amount per rotation of the hydraulic pump from the element and the load speed command value or the discharge flow rate command value of the hydraulic pump A second computing element that outputs, and a limiting circuit that limits the output of the first computing element with the output of the second computing element and outputs the rotational speed command signal;
The first calculation element is a feedback in which an integral amplifying unit for deviation between a load generation force detection value and a load force command value and a zero or higher order differential element of the load generation force detection value itself are coupled in parallel. A hydraulic pump control device comprising a parallel circuit with an amplifying unit. In the hydraulic pump control device according to claim 1 or 2,
The restriction circuit corrects the output of the second calculation element by a discharge pressure detection value of the pressure detection means or a generated force detection value of the force detection means. In the hydraulic-pump control apparatus of any one of Claim 1 or 2 or 3,
A change detecting means for detecting a change in the pressure command value or the force command value of the load, a change rate setting means for setting a change rate of the rotation speed command signal, and a pressure command value or A delay means for changing the rotational speed command signal at a change rate set by the change rate setting means for a preset delay time after a change in the force command value is detected. Hydraulic pump control device. In the hydraulic pump control device according to claim 4,
An adaptive identifier that estimates at least the volume of a load connected to the hydraulic pump, and a delay time changing means that changes the delay time of the delay means based on the output of the adaptive identifier. Hydraulic pump control device. It is a control method of the hydraulic pump control device according to claim 4,
In the delay means, the change rate of the rotation speed command signal is calculated based on the change rate of the discharge pressure detection value of the pressure detection means or the load generation force detection value of the load of the force detection means and the rotation speed command signal. Then, during the preset delay time, the control method of the hydraulic pump control device, wherein the change rate of the rotational speed command signal is limited by the calculated change rate. In the control method of the hydraulic pump control device according to claim 6,
Based on the discharge pressure detection value of the pressure detection means or the change rate of the generated force detection value of the load of the force detection means, at least the volume of the load connected to the hydraulic pump is estimated to calculate the estimated value. A control method for a hydraulic pump control device, wherein a preset delay time is changed based on the estimated value.

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