JPS5990107A - Accelerating and decelerating circuit - Google Patents

Abstract

PURPOSE:To reduce the route error by accelerating the feed speed up to an indicated level with drive of the mobile part of a machine tool or a robot hand, etc. and then performing the acceleration/deceleration control to decelerate the feed speed compared with the indicated speed in a fixed time and regardless of the speed change. CONSTITUTION:Shift registers 4a-4n are connected in series to each other, and the contents are shifted successively to the following registers by a shift pulse gamma. A rough interpolation device 301 delivers the shift amount component DELTAXn to the register 4a for each sampling. When the contents of registers 4a- 4n are referred to as A-N, the addition result XT of an adder 6 is obtained as shown in an equation I from results of multiplications of multipliers 5a-5n. The result XT is divided by a divider 7 to obtain a division result XD as shown by an equation II. The result XD is fed to a distributor 303 which functions as a fine interpolation device. Then an accelerated/decelerated distribution pulse XCP is delivered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration/deceleration circuit that accelerates the feed speed to a command speed and then decelerates it from the command speed, and is particularly suitable for driving moving parts of work machines, robot nodes, etc. The present invention relates to an acceleration/deceleration circuit that provides acceleration/deceleration characteristics.

In a control device that controls axial movement of machine tools, robots, etc., acceleration and deceleration are generally performed at the start and deceleration of axial movement in order to avoid applying shock or imaging to the machine system. There are two methods of acceleration/deceleration as described below. In the following, the case of linear interpolation for two axes, X and Y, will be described, but the same applies to cases of more axes, circular interpolation, etc. Further, the feed rate given the sampling period T1, the amount of movement on the FXX axis is X, the amount of movement on the Y axis is Y1, and the amount of movement in the tangential direction is 5 (-V electric) = Y-).

In the first acceleration/deceleration method, a coarse interpolator calculates ΔS=F・T every sampling period T to obtain a minute movement component ΔS in the tangential direction, and from ΔS, use the following equation to calculate
This method calculates the axial movement amount components ΔX and ΔY, and performs complementary interpolation and acceleration/deceleration by adding a delay to each axis independently for ΔX and ΔY of ΔY−ΔS・□v'¥'+y'' .Figure 1 is the first
It is a block diagram of a control device applying the acceleration/deceleration method of
The coarse interpolator 101 calculates complementary interpolation data ΔX and ΔY for each bone using the feed speed F and the travel amounts X and Y of the X and Y axes (IL
Input to 2X, 102Y. Pulse distributors 102X and 102Y as coarse interpolators receive complementary data ΔX,
A pulse distribution calculation is performed based on ΔY, and a number of distribution pulses XP corresponding to ΔX and ΔY are generated during one sampling time.
YP is generated and input to acceleration/deceleration circuits 103X and 103Y, respectively. Each acceleration/deceleration circuit 10! IX.

103Y has the configuration shown in FIG. 3, assuming that the speed is accelerated or decelerated in an exponential function manner at both rise and fall times as shown in FIG. 2. In addition, in FIG. 3, 3a is the distribution power /l/ output from the pulse distributor 102X (102Y).
SXP (YP) c': Acceleration/deceleration circuit 103X (10
3B is a register that accumulates the pulses output from the synthesis circuit 3a. 3c is an accumulator. 6d is a combination circuit that combines the contents E of register 3b and the contents of accumulator 3C at a constant speed Fc. This is an adder that adds up each pulse P every time it occurs and sets the addition result in the accumulator 3C.

Now, the speed of the distribution pulse xP is F, and the speed of the output pulse XCP is F. Then, the following formula holds true.

po-□・k! , (4J n However, the number of bits of the accumulator 3c is n. Now, in the above equation, equation (6) is the increment per unit time of the register 3b, and equation (4) is the increment per unit time from the accumulator 3c. This is the number of carry pulses (output pulses °xcp) to be output.This (3).

From equation (4), the output pulse F. If we find, Fo=F
(1-exp(-kt)) (5) However, k=
It becomes a constant and the output pulse speed F. accelerates exponentially when starting, and decelerates exponentially when stopping.

Returning to FIG. 1, the output pulses XCP and YCP are exponentially accelerated and decelerated by the acceleration/deceleration circuits 103X and 103Y.
are input to servo circuits 104X and 104Y, which drive servo motors 105X and 105Y, respectively. Fourth
The figure is an explanatory diagram showing the state of complementary interpolation by the coarse interpolator 101.

On the other hand, the second acceleration/deceleration method is a method of accelerating/decelerating by applying acceleration/deceleration to the feed rate itself input to the intersealer.

Figure 5 is a block diagram for realizing the second acceleration/deceleration method;
The figure is an explanatory diagram illustrating the moving state. In FIG. 51, the acceleration/deceleration circuit 201 has almost the same configuration as that in FIG. 6, and exponentially accelerates and decelerates the output pulse Fj when the feed rate F rises and falls. However, deceleration is automatically performed when pulses of feed rate F no longer arrive.

Then, the timing to start deceleration (timing to stop pulse input of feed rate F) is when the deceleration distance (known) according to feed rate F becomes equal to the remaining movement amount.

The interpolator 202 performs pulse distribution calculation based on the movement amount data X, Y every time the output pulse Fj is generated from the acceleration/deceleration circuit 201, generates distribution pulses XP, YP, and outputs the pulses to the servo motor via the servo circuits 104X, 104Y. 105
X, drives 105'l'. As a result, as shown in FIG. 6, the output speed (the amount of movement in one sampling time) of the interpolator 202 gradually increases and decreases when starting and stopping.

As described above, the first and second acceleration/deceleration methods described above have been conventionally performed. In the first method, acceleration/deceleration control can be performed completely independently of interpolation; simply starting interpolation will cause acceleration, and ending interpolation will cause deceleration. This has the advantage of simplifying the configuration of the acceleration/deceleration circuit itself. However, in the first method, it is difficult to provide the same delay for each axis, and since each axis has independent delays, in the case of circular interpolation, it is inevitable to introduce errors in the path after acceleration and deceleration, as shown in Figure 7. It has its drawbacks. The radius error ΔR in Figure 7 is the radius R1.
If the time constant is τ and the command speed is F, then approximately.

On the other hand, although the second acceleration/deceleration method has the advantage of not causing any path errors due to acceleration/deceleration control, in particular, in order to accurately terminate deceleration at the end point of a given movement, Considering that there may be changes in the feed speed such as an override being applied to the given feed speed F, the necessary deceleration distance according to the momentary feed speed and the remaining distance to the end point of movement are always known. It has the drawback that it requires complicated calculations and the interpolator and acceleration/deceleration circuit are extremely complicated.

From the above, it is an object of the present invention to provide a novel acceleration/deceleration circuit that can reduce path errors, realize acceleration/deceleration control with a simple circuit configuration, and obtain arbitrary acceleration/deceleration characteristics. .

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 8 is a block diagram of an embodiment of the present invention (only the X axis is shown in detail). In the figure, 301 is a coarse interpolator, which calculates 1 by calculating the formula (1) and fa.
Complementary interpolation data (travel component) Δ of each axis for each sampling
Generates Xn and ΔYn and inputs them to the acceleration/deceleration circuit.

4a, 4b, . . . , 4n are shift registers, each of which stores a movement amount component ΔXn, and sequentially shifts the movement amount component to a subsequent shift register by a shift pulse τ;
5a...5n are multipliers, and the multipliers 5a to 5n
is to multiply the stored contents of the shift registers 4a to 4n by respective set coefficients by □ to kn.

6 is an adder which adds the multiplication results of each multiplier 5a to 5n, and 7 is a divider which divides the addition result of adder B into the coefficient set in each multiplier 5a to 5n from 0 to 5n. The one that divides by the sum of kn, 303 is an X-axis pulse distributor,
It outputs the number of distribution pulses corresponding to the division result of the divider 7.

Next, the operation of the embodiment shown in FIG. 8 will be explained with reference to the operation diagram shown in FIG. 9.

The shift registers 4a to 4n are connected in series, and the contents are sequentially shifted to the next stage shift register by a shift pulse τ, and the coarse interpolator 301 outputs the latest movement amount component ΔXn every sampling. , are input to the shift register 4a. Therefore, each shift register 4a~
When the content of 4n is A-n, each of the multipliers 5a to 5n at the time of sampling when the movement amount component ΔXrh is output from the coarse interpolator 301 becomes A- and ~N-kn.

From this K, the addition result XT of adder B becomes as shown in the following equation.

XT = A −k, +B− to 2+・= 1N −kn
-(7) This addition result XT is divided by the divider 7 as shown in the following equation to obtain the division result XD.

XD = XT/kT (81 This division result XD is input to the pulse distributor 306 which functions as a fine interpolator, and the distribution pulse XC which is acceleration/deceleration controlled is
P is output.

When the shift pulse τ arrives, the contents of the shift register at each stage are shifted to the shift register at the subsequent stage.

The operations of the adder 6 and divider 7 are executed for each sampling.

The acceleration time and deceleration time of this cutting edge deceleration circuit are determined by the number of soft registers and the period of the shift pulse τ, and the period of the shift pulse τ is equal to or less than the period of the sampling pulse.

Although the aforementioned multipliers 5a to 5n1, adder 6, and divider 7 constitute an arithmetic circuit, it can also be constituted by a single arithmetic means, for example, a microprocessor.

Also, if there is a problem in calculation time regarding sequential shifting of shift registers, it is necessary to determine which buffer should be configured with buffer registers to take out A-N and which buffer should store ΔXn. The shift operation can be eliminated by providing a pointer that indicates . Also, although not shown in FIG. 8, in consideration of the fact that a remainder is generated when dividing by the divider 7, an accumulator and an adder are separately provided, and the remainders at each sampling period are added and accumulated in the 7-accumulator. However, if the method of adding 1 to the output value of the divider and sending it out when the contents of the accumulator exceeds kT, highly accurate acceleration/deceleration can be performed.

Next, a specific example of the present invention will be described with reference to FIG. still,
Acceleration time constant is 40m5eC, sampling period T is am
sec. Therefore, there are 5 shift registers (=40
/8). Also, the input ΔXn to the acceleration/deceleration circuit is 10
The initial values of the shift registers 41 to 45 are set to zero.

First, if the coefficients of each multiplier 51 to 55 are all 1, then at the first sampling time 2, the calculation result XT of equation (7) is p, = 1 o, BN = 0. Therefore, the output of the divider 8 becomes 2.

At the second sampling time, the calculation result of equation (7)
Since A, B=lO1C-N=0, T becomes 20, so the output of the divider 8 becomes 4.

Thereafter, the divider output similarly increases to 6.8.10, and after the time constant of 40m5ec has elapsed, the input ΔX to the acceleration/deceleration circuit
n (-i 0 ) and the acceleration/deceleration circuit output match, and from then on Δ
A constant value of 10 is output from the acceleration/deceleration circuit until Xn no longer arrives. Then, when the arrival of ΔXn ends, the calculation result ~st of equation (7) becomes 40 since A=0 and B~N-10, and the output of the divider 8 ( becomes 8. Thereafter, similarly The output of the divider decreases to 6.4°2.0 and becomes zero after a time constant of 40 m5ec has elapsed.

Therefore, an acceleration/deceleration output XD as shown in FIG. 9 (Bl) is obtained, and straight helix acceleration or deceleration is possible within the time constant regardless of the magnitude of the speed change.

On the other hand, in the above example, each coefficient was set to the same value, but different acceleration/deceleration characteristics can be obtained by changing the value of each coefficient. For example, in the example above, the coefficient k. y k4 is 0.5, k□r
If k3 is 1.0Xk2 is 2.0, then Figure 9 (C1
Acceleration/deceleration output can be obtained as shown below.

These can be set arbitrarily depending on the characteristics of the servo circuit and servo motor, and can be easily achieved only by setting coefficients.

As explained above, according to the present invention, there is provided a storage section that stores n samplings of movement amount components in each axis direction, a storage section that multiplies these movement amount components by a predetermined coefficient, and divides this multiplication result by the sum of the coefficients. Since the acceleration/deceleration time can be accelerated or decelerated in a constant time regardless of the magnitude of the speed change, there is no difference in the delay of each axis, and there is no error in the interpolated path. In addition to the effect that there is no acceleration or deceleration, arbitrary acceleration/deceleration characteristics can be obtained, so the optimum characteristics can be set according to the characteristics of the servo system, and high-speed positioning and high-speed cutting are also possible. Further, the setting of the acceleration/deceleration characteristics can be achieved extremely easily by simply changing the multiplication coefficient, and the configuration is also simple without becoming complicated.

Although the present invention has been described with reference to one embodiment, the present invention is not limited to this embodiment, and various modifications can be made within the scope of the gist of the present invention, and these are not excluded from the scope of the present invention. do not have.

[Brief explanation of the drawing]

Fig. 1 is a block diagram applying the conventional first acceleration/deceleration method, Fig. 2 is an explanatory diagram of exponential function type acceleration/deceleration in Fig. 1,
Fig. 6 is a block diagram of the exponential acceleration/deceleration circuit used in Fig. 1, Fig. 4 is an explanatory diagram of the first acceleration/deceleration method, and Fig. 5 is a block diagram of the conventional second acceleration/deceleration method. , Fig. 6 is an explanatory diagram of the conventional second acceleration/deceleration method, and Fig. 7 is an explanatory diagram of the conventional first acceleration/deceleration method.
FIG. 8 is a block diagram of an embodiment of the present invention, and FIG. 9 is an explanatory diagram of the present invention. In the figure, 501... coarse interpolator, 303... pulse distributor, 4a to 4n... shift register, 5a to 5n...
・Multiplier IE, 6... Adder, 7... Divider Patent applicant Fanasoku Co., Ltd.

Claims (4)

[Claims] (1) In an acceleration/deceleration circuit that accelerates or decelerates the feed speed to a command speed, there is a means for calculating the amount of movement in each axis direction at every sampling period α), and a means for calculating the amount of movement in each axis direction by n.
After multiplying each of the movement amount components for n samplings stored in the storage unit by a coefficient set correspondingly to each of the storage unit that stores the number of samplings and adding the respective multiplication results, the addition result is calculated. An acceleration/deceleration circuit comprising: an arithmetic circuit that divides the sum of the coefficients by the sum of the coefficients. (2) The acceleration/deceleration circuit according to claim (1), wherein the storage section is composed of n shift registers each storing a movement amount component. (3) The acceleration/deceleration circuit according to claim 22, wherein the arithmetic unit is provided corresponding to the shift register and includes n multipliers that multiply the coefficients. (4) The acceleration/deceleration according to claim (3), wherein the calculation unit further includes a multiplier that multiplies the movement amount component inputted to the shift register at the frontmost stage by the coefficient. circuit.