JPH11110048A - Position control servo device and servo control method for position control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive motor speed when the disturbance is canceled by outputting a limit velocity as a speed command if this command produced by a position control means exceeds the limit speed that is shown in a prescribed acceleration/deceleration pattern. SOLUTION: A speed limit output means 12 is added to a servo control part 200 to limit the level of a speed command V' that is outputted from a position controller 2. Then the means 12 executes a system program stored in a system program memory via a CPU based on a limit speed VL sent from a positioning control part 100. If the speed command V' of the controller 2 does not exceed the speed VL that is shown in a prescribed acceleration/ deceleration pattern, the command V' is outputted. Meanwhile, the speed shown in the acceleration/deceleration pattern is outputted as a speed command if the command V' of the controller 2 exceeds the speed VL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position control servo device for controlling a position of a machine by a servomotor and a servo control method for a position control system.

[0002]

2. Description of the Related Art FIG. 7 shows a hardware configuration of a conventional position control servo device. The position control servo device includes a positioning control unit 100 and a servo control unit 200.
, A servo motor 50 and a position detector 51 for detecting the current position of the servo motor 50.

A positioning control unit 100 includes a CPU 101
, A system program memory 102, a user program memory 103, and a two-port memory 104. The servo control unit 200 includes a CPU 201
, System program memory 202, output port 2
03, the input port 204, and the PWM power converter 205
It is composed of

[0006] The positioning control unit 100 is a two-port memory 1
The position command P ^* is output to the servo control unit 200 via the control unit 04. The position command P ^* is a command for gradually changing the command position to the final positioning target position. The position command P ^* is generated by the CPU 101 executing the system program stored in the system program memory 102 based on the user program stored in the user program memory 103, and is written in the two-port memory 104.

Next, a conventional position control servo device will be described with reference to the block shown in FIG. The position control servo device calculates a position deviation by subtracting a position feedback signal (current motor position signal) P output from the position detector 51 from a position command P ^* given by the positioning control unit 100. And a position controller 2 that outputs a speed command V ^* by multiplying the position deviation calculated by the position deviation calculator 1 by the position gain Kp, and a position feedback signal P output by the position detector 51 from the speed command V ^*. Speed feedback signal (current motor speed signal) V obtained by differentiating by differentiator 52
And a speed controller 4 that outputs a torque command τ ^* by multiplying the speed deviation calculated by the speed deviation calculator 3 by a speed gain Kv.
, A torque limiting means 5 for limiting the torque command τ ^* output by the speed controller 4 to be within a predetermined value, and a PWM power converter 205.

The position deviation calculator 1, the position controller 2, the speed deviation calculator 3, the speed controller 4, and the torque limiting means 5 are constituted by software, and the system program memory 20
2 to the CPU 201
Are implemented, but these may be configured by hardware.

Next, the operation will be described. The position command P ^* is a command in which the command position changes gradually at fixed time intervals based on the designated speed, and the position control servo device controls the torque command based on the position command P ^* such that the position deviation always becomes zero. τ ^* is output, the servomotor 50 is driven via the PWM power conversion unit 205, and the position of the servomotor 50 is controlled (positioned) following the position command P ^* . At this time, the torque limiter 5 limits the magnitude of the torque command τ ^* within the torque limit value τL which is the output allowable torque of the servomotor 50.

The deceleration start position is determined by the set deceleration constant and the set speed at the start of deceleration, and the speed switching at the start of deceleration is performed at a command point of a command position that changes at regular time intervals.

When a stop command is input, the vehicle decelerates from the command speed at the time the stop command is input based on a preset deceleration time constant and stops.

[0010]

In the case of the conventional position control servo device, the command speed is calculated based on the position deviation, so that the speed of the servo motor is delayed with respect to the specified speed due to disturbance such as load fluctuation. If the disturbance is canceled in a state where the difference between the current position of the servomotor and the command position is large, the speed command may become excessive and exceed the motor allowable rotation speed. In such a state, there have been problems such as an alarm being generated, an overshoot to the target position, and a shock applied to the servomotor and the load.

Further, when the motor speed is delayed with respect to the designated speed due to a disturbance such as a load change and the difference between the current position and the command position of the servomotor is increased, the operation is immediately stopped when the operation is switched to the deceleration operation. However, there is a problem that the deceleration completion position becomes inaccurate and the final positioning position becomes inaccurate.

Further, when the vehicle is stopped by inputting a stop command, the command position and the current position are different from each other, so that there is a problem that normal operation cannot be performed at the next operation.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to prevent the motor speed from becoming excessive when a disturbance is released, and to reduce the motor speed to a specified speed due to a disturbance such as a load change. Even when the difference between the current position of the servomotor and the command position is large, it is possible to avoid abnormal start of deceleration operation or incorrect positioning. It is an object of the present invention to provide a position control servo device and a position control system servo control method capable of preventing occurrence of abnormal operation during operation.

[0014]

In order to achieve the above-mentioned object, a position control servo device according to the present invention comprises a position detecting means for detecting a position control object or a current position of a servomotor, and a current speed of the servomotor. Speed detecting means for detecting a position command indicating a final positioning target position and a speed command corresponding to a difference between the current position detected by the position detecting means and a position command indicating the final positioning target position. Speed limit output means for outputting the speed command if the speed command does not exceed the speed limit indicated by the predetermined acceleration / deceleration pattern, and outputting the speed indicated by the acceleration / deceleration pattern as the speed command otherwise. A speed for generating a torque command according to a difference between a speed command output by the speed limit output means and a current speed detected by the speed detection means. And control means, said speed control means based on a torque command is outputted in which and a driving means for driving the servo motor.

[0015] The position control servo device according to the next invention is as follows.
The speed limit at the time of acceleration is determined by the following equation. VL = {(T−T0) / Ta} · Vt + V ₀ ^* where VL: speed limit (rev / min) T: current time (seconds) T ₀ : acceleration processing start time (seconds) Ta: rated from stopped state Time required to accelerate the servo motor to the rotation speed (second) Vt: Rated rotation speed of the servo motor (rev / min) V ₀ ^* : Command speed before acceleration (rev / min)

The position control servo device according to the next invention is
The deceleration start position in the acceleration / deceleration pattern is subtracted from the final positioning target position by the deceleration distance and the low speed region distance required to decelerate from the current speed of the servo motor detected by the speed detecting means to the low speed region speed with a predetermined deceleration constant. And ask for it.

The position control servo device according to the next invention is
The deceleration distance is determined by the following equation. Sd = {Np (V ² −Vc ² ) Td} / (2.60 · V
t) where Sd: deceleration distance (p required for deceleration from V to Vc)
ls) Np: Number of one rotation pulse of servo motor (pls / re
v) V: current rotational speed of the servo motor (rev / min) Td: time required to decelerate the servo motor from the rated rotational speed to stop (seconds) Vt: rated rotational speed of the servo motor (rev / min) Vc: low-speed region speed (rev / min)

The position control servo device according to the next invention is as follows.
The speed limit at the time of deceleration is determined by the following equation. V <L within the range of P <Pe ^* -Sl = {[{{2 ^* 60.Vt (Pe ^* -P-Sl)}} /
(Np · Td)] + Vc P ≧ Pe ^* −Sl VL = Vc where VL: Limited speed (rev / min) Vt: Rated rotation speed of servo motor (rev / min) Pe ^* : Final positioning target position (Pls) P: current servo motor position (pls) Sl: low-speed area distance (pls) Np: number of rotation pulses of servo motor (pls / re)
v) Td: Time required to decelerate the servomotor from the rated speed to stop (seconds) Vc: Low-speed region speed (rev / min)

The position control servo device according to the next invention is as follows.
Command position changing means for changing a command position for the servo motor to an actual position of the servo motor by the command position changing means after a stop command is input during execution of position control and the servo motor is stopped. .

[0020] The position control servo device according to the next invention comprises:
As a position command, a position command indicating a final positioning target position and a position command switching means for selecting one of a position command for gradually changing the command position to the final positioning target position are provided. is there.

In order to achieve the above object, a servo control method for a position control system according to the present invention provides a servo control method according to a difference between a position command indicating a final positioning target position and a current position detected by position detecting means. A speed command is generated.If the speed command does not exceed the speed limit indicated by the predetermined acceleration / deceleration pattern, the speed command is output.If the speed command is exceeded, the speed indicated by the acceleration / deceleration pattern is output as a speed command. Then, a torque command corresponding to the difference between the speed command and the current speed is generated to drive the servomotor.

In the servo control method of the position control system according to the next invention, the speed limit during acceleration is determined by the following equation. VL = {(T−T ₀ ) / Ta} · Vt + V ₀ ^* where VL: speed limit (rev / min) T: current time (second) T ₀ : acceleration processing start time (second) Ta: from stop state Time required to accelerate the servo motor to the rated speed (second) Vt: Rated speed of the servo motor (rev / min) V ₀ ^* : Command speed before acceleration (rev / min)

In the servo control method of the position control system according to the next invention, the deceleration distance and the low-speed area distance required to decelerate the deceleration start position in the acceleration / deceleration pattern from the current motor speed to a low-speed area speed with a predetermined deceleration constant. Is subtracted from the final positioning target position.

In a servo control method for a position control system according to the next invention, the deceleration distance is determined by the following equation.

Sd = {Np (V ² −Vc ² ) Td} /
(2 · 60 · Vt) where Sd: deceleration distance required to decelerate from V to Vc (p
ls) Np: Number of one rotation pulse of servo motor (pls / re
v) V: current rotational speed of the servo motor (rev / min) Td: time required to decelerate the servo motor from the rated rotational speed to stop (seconds) Vt: rated rotational speed of the servo motor (rev / min) Vc: low-speed region speed (rev / min)

In the servo control method of the position control system according to the next invention, the speed limit at the time of deceleration is determined by the following equation. Within the range of P <Pe ^* -Sl VL = {[{{2 ^* 60.Vt (Pe ^* -P-Sl)}} /
(Np · Td)] + Vc P ≧ Pe ^* −Sl VL = Vc where VL: Limited speed (rev / min) Vt: Rated rotation speed of servo motor (rev / min) Pe ^* : Final positioning target position (Pls) P: current servo motor position (pls) Sl: low-speed area distance (pls) Np: number of rotation pulses of servo motor (pls / re)
v) Td: Time required to decelerate the servomotor from the rated speed to stop (seconds) Vc: Low-speed region speed (rev / min)

A servo control method for a position control system according to the next invention is to change a command position for the servo motor to an actual position of the servo motor after a stop command is input during execution of the position control and the servo motor stops. It is.

In the servo control method of the position control system according to the next invention, the position command is either a position command indicating a final positioning target position or a position command for gradually changing the command position to the final positioning target position. Either one can be selected.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a position control servo device and a position control system servo control method according to the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, components that are the same as or equivalent to those of the above-described conventional example are denoted by the same reference numerals as those of the above-described conventional example, and description thereof is omitted.

The positioning control unit 100 includes a CPU 101,
A parameter memory 105 is provided in addition to the system program memory 102, the user program memory 103, and the two-port memory 104. Parameter memory 105
Is a parameter table A as shown in FIG.
And a parameter table B as shown in FIG.

The parameter table A is a parameter table for storing a predetermined number of servo motor-specific parameters specified by the servo motor type name, and includes an area for storing the rated rotation speed of the servo motor,
An area for storing the number of rotation pulses is allocated.

The parameter table B is a parameter table in which various parameters required for positioning are stored, and stores a time required for accelerating the servo motor from a stopped state to a rated speed during a normal operation. An area that stores the time required for the servo motor to decelerate from the rotating state at the rated speed to the stop state during normal operation, and the servo motor rotates at the rated speed when a stop command is input. An area that stores the time required to decelerate from a stopped state to a stopped state, an area that stores a low-speed area distance that is a distance at which low-speed operation is performed just before the stop state, and a low-speed area that is a speed in low-speed operation The area to store the speed is assigned.

The parameters stored in the parameter tables A and B are used for calculating a deceleration start position, a speed limit, and the like.

The positioning control unit 100 controls the position command Pe ^* indicating the final positioning target position or the previous position command P ^*.
And the speed limit VL to the servo control unit 200 via the two-port memory 104, and the servo control unit 200 stores the current motor position P and the current motor speed V in the two-port memory 10
4 to the positioning control unit 100.

Next, the positioning control device according to the present invention will be described with reference to the block diagram shown in FIG.

The positioning control section 100 includes a position command switching means 11. The position command switching means 11 selectively switches between the switching position a and the switching position b, and outputs a position command to be output to the servo control unit 200 to the position command Pe ^* indicating the final positioning target position (hereinafter, the final positioning target position). To P
e ^* ), and the previous position command P ^* that gradually changes the command position to the final positioning target position ^.
Is switched.

The switching of the position command switching means 11 is performed by the CPU 101 based on the user program stored in the user program memory 103.
02 is executed by executing a system program stored in the system.

The servo control unit 200 further includes a speed limit output unit 12 for limiting the magnitude of the speed command V ^* output from the position controller 2. The speed limit output means 12 is embodied by the CPU 201 executing the system program stored in the system program memory 202 based on the speed limit VL sent from the positioning control unit 100, and the position controller 2 outputs. If the speed command V ^* does not exceed the speed limit VL indicated by the predetermined acceleration / deceleration pattern, the speed command V ^* is output. If the speed command V ^* exceeds the speed limit, the speed indicated by the acceleration / deceleration pattern is output as the speed command. is there.

In this position control servo device, when the position command switching means 11 of the positioning control unit 100 is switched to the switching position b, the position command Pe ^* indicating the final positioning target position is output to the servo control unit 200. The servo control unit 200 determines the position gain Kp, the speed gain Kv, the torque limit value τL and the positioning control unit 1
Position command Pe ^* and speed limit V sent from 00
The position control (positioning) is performed by driving the servomotor 50 based on L.

Further, in this position control servo device, the position deviation obtained as the difference between the position command Pe ^* and the position feedback signal P becomes excessive before the positioning is completed. The speed command V ^* is output, but the speed command V ^* is limited by the speed limit output unit 12 so as not to exceed the speed limit value indicated by the predetermined acceleration / deceleration pattern.

Then, based on a speed deviation obtained as a difference between the output of the speed limit output means 12 and the speed feedback signal V, the vehicle is accelerated with a torque not exceeding a preset torque limit value τL, and the speed is increased from the current speed to a predetermined speed. Decelerate with a torque that does not exceed the preset torque limit value τL.

(Acceleration Control) Next, control during acceleration of the servo motor 50 will be described. Speed limit during acceleration (speed indicated by acceleration / deceleration pattern) VL
Is the time elapsed from the start of acceleration (T−T ₀ ), the time Ta required for the rotation speed of the servo motor 50 to reach the rated rotation speed from the stopped state, the rated rotation speed Vt of the servo motor, And command speed V ₀ before acceleration
Based on ^* , it is calculated by the following equation (1).

VL = {(T−T ₀ ) / Ta} · Vt + V ₀ ^* (1) where VL: speed limit (rev / min) T: current time (second) T ₀ : start of acceleration processing Time (seconds) Ta: Time required for accelerating the servo motor from the stop state to the rated speed (seconds) Vt: Rated speed of the servo motor (rev / min) V ₀ ^* : Command speed before acceleration (rev / The time Ta required for accelerating the servo motor from the stop state to the rated rotation speed and the rated rotation speed Vt of the servo motor can be obtained from the parameter tables A and B.

The reason why the equation (1) is satisfied is as follows. By multiplying the rated speed Vt of the servo motor the ratio of (acceleration time Ta until the rated speed of the servomotor) (current and time T acceleration process starting time T ₀ of the difference) between the acceleration process start time T ₀ From the current time T to the current time T. The speed limit VL at the current time T is obtained by adding the command speed V ₀ before acceleration to the speed increase.

V ₀ = 0 at the start of servo motor positioning
Therefore, the arithmetic expression of Expression (1) is satisfied when the speed limit VL is equal to or less than the commanded speed V ₁ ^* after acceleration, that is, under the condition of VL ≦ V ₁ ^* . In a normal acceleration / deceleration pattern,
First, when the constant acceleration is performed and the command speed V ₁ ^* after the preset acceleration is reached, the positioning control unit 100 sets the speed limit VL to the command speed V ₁ ^* , and sets the constant speed operation state by the command speed V ₁ ^*. It shifts to.

(Deceleration Stop Control) Next, a series of processes for stopping at the final positioning target position will be described with reference to FIG. FIG. 5 shows a flow of processing performed by the positioning control unit 100 when calculating the deceleration start position in the positioning to the final positioning target position and calculating the speed limit VL during deceleration in real time.

In this processing flow, first, the servo control unit 2
The current motor speed V and the current motor position P sent from 00 to the positioning control unit 100 via the two-port memory 104 are recognized (steps S10 and S2).
0).

Next, a comparison is made between the current position P of the servomotor and the deceleration start position Pd (step S30). If the current position of the servo motor does not exceed the deceleration start position Pd calculated in the previously executed step S50 (No in step S30), the deceleration distance Sd and the deceleration start position Pd are calculated (step S40, step S5).
0).

The deceleration distance Sd is calculated by the following equation (2). That is, Sd = {Np (V ² −Vc ² ) Td} / (2 · 60 · Vt) (2) where Sd: deceleration distance (pl required for deceleration from V to Vc)
s) Np: Number of rotation pulses per servo motor (pls / re)
v) V: current rotational speed of the servo motor (rev / min) Td: time required to decelerate the servo motor from the rated rotational speed to stop (seconds) Vt: rated rotational speed of the servo motor (rev / min) Vc: low-speed region speed (rev / min), time Td required to decelerate the servomotor from the rated rotation speed to the stop, the rated rotation speed Vt of the servomotor, low-speed region speed Vc, The number Np of rotation pulses can be obtained from the parameter tables A and B.

Time Td required for the servo motor to decelerate from a state where it is rotating at the rated rotation speed Vt to a stop.
Is Td / 60 when the unit is adjusted to the minute.

The reason why the equation (2) holds is as follows. Since the motor decelerates at a constant deceleration, the time required to decelerate from the current rotational speed V of the servo motor to the low speed region speed Vc [(Td / 60) · {(V−Vc) / Vt}]
Is multiplied by the change in speed (V-Vc), divided by 2, and the time [(Td / 60) ｛(V-Vc) / V
[td]] and a value obtained by multiplying the multiplied value by the low-speed region speed Vc to add a deceleration distance {(Td / 60) · (V ² −Vc ² ) / 2 · Vt} required to decelerate from V to Vc. (Unit: rev) is obtained. By multiplying this deceleration distance by the number of pulses Np in one rotation of the motor, the deceleration distance S
d (unit: pls) is obtained.

The deceleration start position Pd is calculated by the following equation (3). That is, Pd = Pe ^* -Sd-Sl (3) where Pd: deceleration start position (pls) Pe ^* : final positioning target position (pls) Sd: deceleration distance (pls) Sl: low speed area distance (pls) ), And the low-speed area distance S1 can be obtained from the parameter table B. The deceleration start position Pd is a deceleration distance Sd from the final positioning target position Pe ^{* according} to the equation (2).
And the low-speed area distance S1 of the parameter setting is calculated.

The current position P of the servomotor is the deceleration start position Pd calculated in the previous step S50.
Is exceeded (Yes at step S30), a speed limit (speed limit value) VL for deceleration is calculated (step S60).

The speed limit VL is calculated by the following equation (4).
It is calculated by (5). That is, VL = {[{2 · 60 · Vt (Pe ^* −P−Sl)} / (Np · Td)] + Vc in the range of P <Pe ^* −Sl (4) P ≧ Pe ^* −Sl VL = Vc (5) where VL: speed limit (rev / min) Vt: rated speed of the servo motor (rev / min) Pe ^* : final positioning target position (pls) P: current Servo motor position (pls) Sl: low-speed area distance (pls) Np: number of rotation pulses of servo motor (pls / re)
v) Td: Time required to decelerate the servomotor from the rated rotation speed to the stop (seconds) Vc: Low-speed region speed (rev / min), which decelerates the servomotor from the rated rotation speed Vt to the stop. , The rated rotation speed Vt of the servo motor, the low-speed region distance S1, and the number Np of single rotation pulses of the servo motor can be obtained from the parameter tables A and B.

At the current motor position P, the remaining reduction
The speed distance is the final positioning target position Pe ^*From the current motor
The position and the low speed region distance Sl are reduced (Pe^*-PS
l), the equation V = √ [(2 ·
60 · Vt · Sd) / (Np · Td)] + Vc
And Sd to (Pe^*-P-Sl) and V to VL
Equation (4) is obtained by the replacement.

The speed limit VL is such that the current motor position P is the maximum.
Final positioning target position Pe^*From the low-speed area distance Sl
Until the pulling position is reached, that is, (P <Pe^*−
Within the range of S1), it is calculated by equation (4).
After that, that is, (P ≧ Pe ^*-Sl),
The speed becomes the low speed region speed Vc as shown in the equation (5).

Next, after the motor speed has reached the low speed region speed, the current motor position P is compared with the final positioning target position Pe ^* (step S70). The limit value VL is set to 0 (step S80), and the servomotor is stopped.

(Control at Stop Command Input Time) Next, a process when a stop command is input before the servo motor is positioned to the final positioning target position Pe ^* will be described with reference to FIG. FIG. 6 shows a processing flow of the positioning control unit 100 when the stop command is input before the positioning to the final positioning target position is processed in real time.

In this processing flow, first, it is determined whether or not a stop command has been input (step S100).
The current motor speed V and the current motor position P sent from the servo controller 200 to the positioning controller 100 via the two-port memory 104 are recognized (step S11).
0, step S120).

Next, the post-stop input speed limit Ve is calculated by the following equation (6). That, Ve = √ [{2 · 60 · Vt (St- (P-Ps))} / (Np · Ts)] St = (Np · Vs 2 · Ts) / (2 · 60 · Vt) ··· (6) where, Ve: speed limit after stop input (rev / min) St: required deceleration distance at stop (pls) Ve: speed limit after stop input (rev / min) Nd: number of one rotation pulse of servo motor (pls) / Re
v) Vs: Motor speed at the time of stop input (rev / min) Ts: Time required to decelerate the servo motor from the rated rotation speed to stop at the time of stop input (seconds) Vt: Rated rotation speed of the servo motor (rev) / Min) P: current motor position (pls) Ps: motor position at the time of stop input, and motor speed Vs at the time of stop input is step S110
Is the motor speed V at the time of the stop input detected in
The motor position Ps at the time of the stop input is the motor position P at the time of the stop input detected in step S120.
The time Ts required to decelerate the servomotor from the rated speed to the stop, and the rated speed Vt of the servomotor
Can be obtained from the parameter tables A and B.

Next, it is determined whether or not the servomotor is stopped (step S140). If the servomotor is operating, the process proceeds to an end step. If the servomotor is stopped, the command position of the servomotor is changed to the current position of the servomotor in preparation for the next operation (this stop command operation mode is released and ready for the next operation). (Step S1)
50).

After confirming that the speed finally becomes 0 in the equation (6) and the servomotor is stopped,
As described above, the command position is changed so that the command position of the servo motor becomes the actual position of the servo motor in preparation for the next operation. By changing the command position, the remaining position deviation becomes zero. The position changing means for changing the command position is realized by the CPU 101 of the positioning control unit 100 executing a system program based on the current servo motor position P.

In the above description, the case where the positioning is performed by the position command Pe ^* has been described. However, by switching the position command switching means 11 (switching position a side), the control by the normal position command P ^* , that is, the conventional Needless to say, position control in which command positions are sequentially given can be performed as in the technology.

[0064]

As will be understood from the above description, according to the position control servo device of the present invention, the difference between the position command indicating the final positioning target position by the position control means and the current position detected by the position detection means. If the speed command output by the position control means by the speed limit output means does not exceed the speed limit indicated by the predetermined acceleration / deceleration pattern, the speed command is output,
If it exceeds, the speed indicated by the acceleration / deceleration pattern is output as a speed command, and the speed control means outputs a torque command corresponding to the difference between the speed command output by the speed limit output means and the current speed detected by the speed detection means. Generates and drives the servomotor based on the torque command output from the speed control means by the drive means, so that the motor speed is delayed with respect to the specified speed due to disturbances such as load fluctuations, and the difference between the current position of the servomotor and the commanded position. Even if the disturbance is canceled while the speed is large, the speed is controlled so as not to exceed the speed specified by the acceleration / deceleration pattern, and it is possible to prevent an alarm from being generated due to an excessive speed, damage to the device, and the like. At the same time, an effect that the servo motor can be smoothly stopped at the positioning target position can be obtained.

According to the position control servo device of the next invention, the speed limit VL at the time of acceleration is expressed by VL = ｛(T−
T ₀ ) / Ta｝ · Vt + V ₀ ^* Determined by an arithmetic expression, the effect is obtained that the speed limit VL during acceleration is appropriately set without excess or deficiency.

According to the position control servo device of the next invention, the deceleration start position in the acceleration / deceleration pattern is decelerated from the current speed of the servomotor detected by the speed detecting means to the low speed region speed with a predetermined deceleration constant. Since the required deceleration distance and low-speed area distance are obtained by subtracting from the final positioning target position, the motor speed is delayed with respect to the specified speed due to disturbance such as load fluctuation, and the difference between the current position of the servo motor and the command position is large. Even in the state, the effect of preventing abnormal start of deceleration operation and inaccuracy of the deceleration completion position is obtained, and a low-speed region is secured, so that the shock applied to the servo motor and load when the final positioning target position stops can be reduced. Also, the effect that accurate positioning can be obtained is obtained.

According to the position control servo device of the next invention, the deceleration distance Sd is set as follows: Sd = ｛Np (V ² −Vc ² )
Td 決定 / (2 · 60 · Vt) is determined by an arithmetic expression, so that the deceleration distance Sd is appropriately set without excess / shortage.
Even when the difference between the current position of the servo motor and the command position is large, the effect of preventing the abnormal start of the deceleration operation and the inaccuracy of the deceleration end position can be obtained. Shock applied to the servomotor and load when the positioning target position is stopped can be reduced, and an effect that accurate positioning can be performed can be obtained.

According to the position control servo device of the next invention, the speed limit VL at the time of deceleration is set to P <Pe ^* -S
l, VL = [｛2.60 · Vt (Pe ^*
−P−Sl)｝ / (Np · Td)] + Vc. In the range of P ≧ Pe ^* −Sl, the speed is determined by the formula of VL = Vc. Therefore, the effect of being appropriately set is obtained.

According to the position control servo device of the next invention, after the stop command is input during the execution of the position control and the servomotor is stopped, the command position for the servomotor is changed to the actual position of the servomotor by the command position changing means. Therefore, an effect that an abnormal operation can be prevented from occurring during the next operation can be obtained.

According to the position control servo device of the next invention, the position command switching means gradually changes the position command as the position command indicating the final positioning target position and the command position to the final positioning target position. Since either one of the position commands can be selected, the operation can be performed by a normal position command that gradually changes the command position to the final positioning target position, and the effect that the application range of the device can be expanded is obtained. Can be

According to the servo control method of the position control system according to the next invention, a speed command corresponding to the difference between the position command indicating the final positioning target position and the current position detected by the position detecting means is generated, and the speed command is generated. If the speed command does not exceed the speed limit indicated by the predetermined acceleration / deceleration pattern, the speed command is output.If the speed command speed exceeds the speed limit, the speed command is output as the speed command. Since the servo motor is driven by generating a torque command according to the difference, in a state where the difference between the current position and the command position of the servo motor is large due to the motor speed being delayed with respect to the specified speed due to disturbance such as load fluctuation. Even if the disturbance is released, the speed is controlled so as not to exceed the speed specified by the acceleration / deceleration pattern, Etc. with the possible prevention of the generation and damage to equipment, the effect can be stopped smoothly servomotor target position is obtained.

According to the servo control method of the position control system according to the next invention, the speed limit VL at the time of acceleration is set to VL =
{(T−T ₀ ) / Ta} · Vt + V ₀ ^{* Since it is} determined by an arithmetic expression, the effect is obtained that the speed limit VL during acceleration is appropriately set without excess or deficiency.

According to the servo control method of the position control system according to the next invention, the deceleration start position in the acceleration / deceleration pattern is determined by the deceleration distance required to decelerate from the current speed of the servomotor to the low speed region speed with a predetermined deceleration constant. Since the low-speed area distance is obtained by subtracting the final positioning target position from the final positioning target position, even in a state where the motor speed is delayed with respect to the specified speed due to disturbance such as load fluctuation, and the difference between the current position of the servo motor and the command position is large, The effect of preventing abnormal start of the deceleration operation and inaccuracy of the deceleration end position is obtained.
In addition, a low-speed region is secured, the shock applied to the servomotor and the load when the final positioning target position is stopped can be reduced, and the effects of accurate positioning can be obtained.

According to the position control system servo control method according to the next aspect of the present invention, the deceleration distance Sd is calculated as follows: Sd = ｛Np (V
² -Vc ² ) Td｝ / (2 · 60 · Vt), so that the deceleration distance Sd is appropriately set without excess or shortage, and the difference between the current position of the servo motor and the command position increases. In this state, it is possible to prevent the abnormal start of the deceleration operation and the inaccuracy of the deceleration completion position.Also, a low-speed region is secured, and the shock applied to the servomotor and load when the final positioning target position stops is reduced. It is possible to reduce the number and obtain an effect that accurate positioning can be performed.

According to the servo control method of the position control system according to the next invention, the speed limit VL at the time of deceleration is set to P <P
Within the range of e ^* −S1, VL = √ [｛[2 · 60 · Vt]
(Pe ^* −P−Sl)｝ / (Np · Td)] + Vc, the equation VL = V is within the range of P ≧ Pe ^* −Sl.
Since the speed is determined by the operation formula based on Vc, the effect that the speed limit VL at the time of deceleration is appropriately set without excess or deficiency is obtained.

According to the servo control method of the position control system according to the next invention, the command position for the servo motor is changed to the actual position of the servo motor after the stop command is input during the execution of the position control and the servo motor stops. This has the effect of preventing the occurrence of abnormal operation during the next operation.

According to the servo control method of the position control system according to the next invention, as the position command, a position command indicating the final positioning target position and a position command for gradually changing the command position to the final positioning target position are provided. Since either one can be selected, an operation can be performed by a normal position command that gradually changes the command position to the final positioning target position, and the effect that the application range of the device can be expanded is obtained.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram showing one embodiment of a position control servo device according to the present invention.

FIG. 2 is a block diagram showing one embodiment of a position control servo device according to the present invention.

FIG. 3 is an explanatory diagram showing a parameter table in which parameters unique to a servomotor used in the position control servo device according to the present invention are stored.

FIG. 4 is an explanatory diagram showing a parameter table in which parameters relating to positioning processing used in the position control servo device according to the present invention are stored.

FIG. 5 is a flowchart showing processing at the time of deceleration to a final positioning target position in the servo control method of the position control system according to the present invention.

FIG. 6 is a flowchart showing processing when a stop command is input in the position control system servo control method according to the present invention.

FIG. 7 is a hardware configuration diagram of a conventional position control servo device.

FIG. 8 is a block diagram showing a schematic configuration of a conventional position control servo device.

[Explanation of symbols]

Reference Signs List 1 position deviation calculator, 2 position controller, 3 speed deviation calculator, 4 speed controller, 5 torque limiting means, 11 position command switching means, 12 speed limit output means, 50, servo motor, 51 position detector, 100 Positioning control unit, 200 servo control unit, 205 PWM power conversion unit.

Claims (14)

[Claims] 1. A position detecting means for detecting a current position of a position control object or a servomotor, a speed detecting means for detecting a current speed of a servomotor, a position command indicating a final positioning target position, and the position detecting means. A position control means for generating a speed command corresponding to a difference from the detected current position; and a speed command if the speed command output by the position control means does not exceed a speed limit indicated by a predetermined acceleration / deceleration pattern. Speed limit output means for outputting the speed indicated by the acceleration / deceleration pattern as a speed command if the speed is exceeded, a speed command output by the speed limit output means and a current speed detected by the speed detection means. Speed control means for generating a torque command according to the difference between the servomotor and the servomotor based on the torque command output by the speed control means. Position control servo apparatus characterized by comprising driving means for driving, the. 2. The position control servo device according to claim 1, wherein the speed limit during acceleration is determined by the following equation. VL = {(T−T ₀ ) / Ta} · Vt + V ₀ ^* where VL: speed limit (rev / min) T: current time (second) T ₀ : acceleration processing start time (second) Ta: from stop state Time required to accelerate the servo motor to the rated speed (seconds) Vt: Rated speed of the servo motor (rev / min) V ₀ ^* : Command speed before acceleration (rev / min) 3. The deceleration start position in the acceleration / deceleration pattern is a deceleration distance and a low-speed area distance required to decelerate from the current speed of the servomotor detected by the speed detection means to a low-speed area speed with a predetermined deceleration constant. 3. The position control servo device according to claim 1, wherein the position control servo device is obtained by subtracting from a positioning target position. 4. The position control servo device according to claim 3, wherein the deceleration distance is determined by the following equation. Sd = {Np (V ² −Vc ² ) Td} / (2.60 · V
t) where Sd: deceleration distance (p required for deceleration from V to Vc)
ls) Np: Number of one rotation pulse of servo motor (pls / re
v) V: Current rotational speed of the servo motor (rev / min) Td: Time required to decelerate the servo motor from the rated rotational speed to stop (seconds) Vt: Rated rotational speed of the servo motor (rev / min) Vc: low-speed region speed (rev / min) 5. The position control servo device according to claim 1, wherein the speed limit at the time of deceleration is determined by the following equation. Within the range of P <Pe ^* -Sl VL = {[{{2 ^* 60.Vt (Pe ^* -P-Sl)}} /
(Np · Td)] + Vc P ≧ Pe ^* −Sl VL = Vc where VL: Limited speed (rev / min) Vt: Rated rotation speed of servo motor (rev / min) Pe ^* : Final positioning target position (Pls) P: current servo motor position (pls) Sl: low-speed area distance (pls) Np: number of rotation pulses of servo motor (pls / re)
v) Td: Time required to decelerate the servomotor from the rated speed to stop (seconds) Vc: Low-speed region speed (rev / min) 6. A command position changing means, wherein after a stop command is input during execution of position control and the servomotor is stopped,
The position control servo device according to any one of claims 1 to 5, wherein the command position changing means changes a command position for the servo motor to an actual position of the servo motor. 7. A position command switching means for selecting one of a position command indicating a final positioning target position and a position command for gradually changing the command position to the final positioning target position as the position command. The position control servo device according to any one of claims 1 to 6, wherein: 8. A speed command is generated according to a difference between a position command indicating a final positioning target position and a current position detected by the position detecting means, and the speed command determines a speed limit indicated by a predetermined acceleration / deceleration pattern. If the speed command is not exceeded, the speed command is output.If the speed command is exceeded, the speed indicated by the acceleration / deceleration pattern is output as a speed command, and a torque command corresponding to the difference between the speed command and the current speed is generated. And a servo control method for a position control system. 9. The servo control method for a position control system according to claim 8, wherein the speed limit during acceleration is determined by the following equation. VL = {(T−T0) / Ta} · Vt + V ₀ ^* where VL: speed limit (rev / min) T: current time (second) T ₀ : acceleration processing start time (second) Ta: rated from stopped state Time required to accelerate the servo motor to the rotation speed (second) Vt: Rated rotation speed of the servo motor (rev / min) V ₀ ^* : Command speed before acceleration (rev / min) 10. A deceleration start position in an acceleration / deceleration pattern is obtained by subtracting a deceleration distance and a low speed region distance required to decelerate from a current motor speed to a low speed region speed with a predetermined deceleration constant from a final positioning target position. The servo control method for a position control system according to claim 8, wherein: 11. The method according to claim 10, wherein the deceleration distance is determined by the following equation. Sd = {Np (V ² −Vc ² ) Td} / (2.60 · V
t) where Sd: deceleration distance (p required for deceleration from V to Vc)
ls) Np: Number of one rotation pulse of servo motor (pls / re
v) V: Current rotational speed of the servo motor (rev / min) Td: Time required to decelerate the servo motor from the rated rotational speed to stop (seconds) Vt: Rated rotational speed of the servo motor (rev / min) Vc: low-speed region speed (rev / min) 12. The servo control method for a position control system according to claim 8, wherein the speed limit at the time of deceleration is determined by the following equation. Within the range of P <Pe ^* -Sl VL = {[{{2 ^* 60.Vt (Pe ^* -P-Sl)}} /
(Np · Td)] + Vc P ≧ Pe ^* −Sl VL = Vc where VL: Limited speed (rev / min) Vt: Rated rotation speed of servo motor (rev / min) Pe ^* : Final positioning target position (Pls) P: current servo motor position (pls) Sl: low-speed area distance (pls) Np: number of one rotation pulse of servo motor (pls / re)
v) Td: Time required to decelerate the servomotor from the rated rotation speed to stop (seconds) Vc: Low-speed region speed (rev / min) 13. The servomotor according to claim 8, wherein a command position for said servomotor is changed to an actual position of said servomotor after a stop command is input during execution of position control and the servomotor is stopped. The servo control method of the position control system according to any one of the above. 14. As the position command, any one of a position command indicating a final positioning target position and a position command for gradually changing the command position to the final positioning target position can be selected. The servo control method for a position control system according to claim 8.