JPH01237806A - Acceleration/deceleration controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an acceleration/deceleration control device that performs control to accelerate or decelerate at a constant acceleration when driving a machine tool or a robot arm, etc. On the other hand, this invention relates to an acceleration/deceleration control device that can accelerate or decelerate at a constant acceleration.

[Prior Art] Conventionally, when driving a machine, acceleration/deceleration control is performed to prevent shock or vibration from being applied to the mechanical system when starting or stopping the machine. In this type of acceleration/deceleration control, a linear acceleration/deceleration control method that performs acceleration or deceleration at a constant acceleration that does not exceed the maximum allowable acceleration determined by the drive system capacity and machine characteristics is desired in order to shorten the drive time. There is.

FIG. 7 is a block diagram of a conventional acceleration/deceleration control device disclosed in Japanese Patent Application Laid-Open No. 59-62909. In the figure (la) (
1b)...(1n) is n buffer registers, (2
) is an adder, (3) is an accumulator that temporarily stores the addition result, (4) is a transfer register for the addition result, (5)
is a divider that divides the addition result by l/n. Each buffer register (la) to (in) is connected in series, and for each sampling, the movement amount in this sampling period is the command speed V,
The signal is then input to the first stage buffer register (1a).

At the same time, the contents of each buffer register are transferred to the next stage buffer register, and the contents V(i-n) of the last stage buffer register (in) are sent to the input of the adder (2).

Transfer register (4) at sampling time 1-1
If the content of is 5(1-1), at sampling time i, the output S1 of the adder (2) is S −8+V −
V(1-n) i (1-1) 1 However, S. -Q, V--0, and this result is stored in the accumulator (3),
A divider (5) divides the result by 17n and outputs the result. Note that the above V--O is a simplified representation that in v (i), the values corresponding to i from O to n are 0.

From the above, the output speed F,1 is Fi--φ81 becomes.

On the other hand, the addition result S1 of the accumulator (3) is sent to the transfer register (4) and is sent to the adder (2) at the next sampling time.
) is the input.

With the above configuration, the command speed (
10a) Output speeds (lla) and (llb) with linear acceleration/deceleration characteristics for inputs of (fob), respectively
is given.

[Problems to be Solved by the Invention] Since the conventional acceleration/deceleration control device is configured as described above, if the sampling period is ΔT, the acceleration/deceleration time constant is constant as T-n·ΔT, and If the commanded speed is V, the acceleration a becomes a - V / T, which changes in proportion to the commanded speed. Therefore, it is necessary to select the time constant T so as to satisfy the maximum allowable acceleration at the maximum command speed.In this case, if the command speed becomes small, the drive system will be driven in an area below the maximum allowable acceleration, and the drive system's capacity will be maximized. I can't make it work.

In addition, in order to perform fine acceleration/deceleration control, it is necessary to select a sufficiently small ratio sampling period ΔT to the time constant T, which requires a large number of buffer registers n (-T/ΔT), which complicates the configuration. Become.

Furthermore, when moving at a command speed V with a short moving pressure ML, the moving time t-L/■ becomes smaller than the time constant T, as shown in FIG. There is a problem that the maximum speed can only be increased up to V-t/T, and therefore the positioning time becomes long.

This invention was made in order to solve the above-mentioned problems, and has an acceleration/deceleration characteristic of -constant acceleration in response to changes in command speed, and a short travel time for short-distance travel commands. The object of the present invention is to obtain an acceleration/deceleration control device that generates the shortest output speed, has a quick response, and realizes fine speed control.

[Means for Solving the Problems] The acceleration/deceleration control device according to the present invention calculates the following distance by integrating the difference between the command speed and the output speed at regular sampling intervals, and calculates the deceleration distance from the output speed and the acceleration command value. seek,
The output speed is calculated and output using the following distance, deceleration distance, and acceleration command value.

[Operation: In this invention, the output speed is calculated by comparing the following distance and the deceleration distance, determining acceleration or deceleration, and accelerating or decelerating the output speed at a constant acceleration until it matches the command speed. , generates a speed output that accurately moves the moving distance, which is the integral value of the commanded speed. It also generates an optimal triangular wave speed output that accelerates and decelerates at a constant rate even when the travel distance is short.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the invention, FIG. 2 is a flowchart showing the control operation of an embodiment of the acceleration/deceleration control device of the invention, and FIG. 3 is a numerical diagram showing the acceleration/deceleration control device of the invention. It is a block diagram when applied to a control device (hereinafter referred to as an NC device).

In Fig. 1, (20) is the first calculation section, the following distance calculation section, which integrates the difference between the commanded speed and the output speed, and calculates the distance between the commanded position and the current output position, that is, the following distance. It is something to do. (21) is a deceleration distance calculation unit which is a second calculation unit, and calculates the distance traveled while decelerating from the current output speed to zero at a given acceleration, that is, the deceleration distance.

(22) is an output speed calculation section which is the third calculation section, and this output speed calculation section (22) has a first comparator (23) that compares the command speed and the output speed, and a first comparator (23) that compares the following distance and deceleration distance. It consists of a second comparator (24) for comparison and a speed calculation section (25) for calculating the output speed based on the results of these comparisons.

In Figure 3, (35) is the main control CPU
(CPU: central processing unit) is an arithmetic processing unit that analyzes input information such as NC tape input and manual data input, and performs arithmetic control. (3B) is a tape reader, (37) is C
The RT display board is a setting display board for communicating between the operator and the NC device. (38) is the main memory. (40) is a servo control that performs servo control processing of the machine, (41) is a servo CPU, (42) is an interrupt circuit, (43) is a 2-port memory composed of RAM, and (44) is composed of ROM. control memories, (45a), (45b) and (4
5c) is the interface, (46) is the servo output control, (47) is the feedback control, <
48) is a drive unit, (49) is a servo motor, (
50) is a detector.

Note that Ll is a control line, L2 is an address line, and L3 is a data line.

In the configuration shown in FIG. 3, the procedure for executing the acceleration/deceleration control shown in FIG. 2 is stored in the control memory (44) as a control program.
is stored in.

The interrupt circuit (42) generates an interrupt to the servo CPU (41) at every fixed sampling period ΔT.

The command speed is created by the main control CPU (35) and sent to the servo CPU through the 2-port memory (43).
(41).

The servo CPU (41) reads the command speed in the two-port memory (43) based on the control program in the control memory (44), executes acceleration/deceleration control processing, and calculates the output speed.

Furthermore, the feedback signal of the feedback control (47) is input through the interface (45c), compared with the output speed, the difference is calculated, and the servo output control (47) is inputted through the interface (45c).
It also executes servo control processing such as output to 6).

Note that the servo output control (46) converts the input from the interface (45c) into digital/analog and outputs it to the drive unit (48). The output is amplified by the drive unit (48) and the servo motor (
49). Feedback control (4
7) counts feedback pulses from the detector (50) and outputs them to the interface (45c).

Next, the operation of acceleration/deceleration control will be explained according to the flowchart shown in FIG.

The series of control operations shown in FIG. 2 are performed based on an interrupt generated from the interrupt circuit (42), that is, at every fixed sampling period ΔT.

First, when an interrupt occurs, the servo CPU (41)
reads the command speed v1 from the 2-port memory (43) (step Sl).

Next, the following distance calculating section (20) integrates the difference between the commanded speed and the output speed to obtain the distance between the commanded position and the current output position, that is, the following distance. This is calculated using the following formula (1). That is, the following distance at sampling time i,
Using command speed v1 and previous output speed F(1-1), L1″″” (1-1) i (1-1)
"' (1)+V -F However, L.-0, Fo-0 is calculated (step S2).

Next, the deceleration distance calculating section (21) calculates the distance traveled while decelerating from the current output speed to zero at the given acceleration. This is calculated using the following formula (2). That is, the deceleration distance corresponding to the previous output speed F(1-1) is calculated as 2·ΔF (step S3). Here, ΔF is an acceleration command value (hereinafter simply referred to as acceleration), which is the amount of speed change between sampling periods. Note that this acceleration ΔF is a constant determined by the machine to be controlled, and is stored in the control memory (44).

The operation of the output speed calculation section (22) is shown by the dotted line section (30) in the flowchart of FIG.

That is, first, the first comparator (23) compares the command speed V1 and the previous output speed F(i-1) (step S4), and then the second comparator (24) compares the following distance L1 and deceleration. Comparing the distances (step S5 or S6), (a)
There are four cases shown in (b), (c), and (d). In response to these results, the speed calculation unit (25) performs the operation indicated by the dashed-dotted line (31).

First, in (a), the command speed V1 is the output speed F(1-1)
Because it is larger, we are in a situation where we are accelerating, but the follow-up pressure is 1l.
Since itL is smaller than the deceleration distance #D1, the output speed is kept at the previous value (step S7) and waits until the following distance L exceeds the deceleration distance D1.

In (b), the command speed ■1 is greater than the output speed F(1-1), and the following distance RI is greater than the deceleration distance D1. At this time, compare the added value of the previous output speed F(i-1) and acceleration ΔF with the commanded speed V1 (step S8), and if the added value exceeds the commanded speed V, set the commanded speed v1 as the output speed Fi. If the output speed does not exceed step S9), the added value is set as the output speed F1.
(Step 510).

Case (C) occurs when a movement command is given for a short distance at a high command speed, and in this case, even though the command speed V is smaller than the output speed F, i (
1-1) First, since the following distance L1 is larger than the deceleration distance D1, the output speed is accelerated. This is the same process as step 10 described above, and the sum of F(1-1) and ΔF is output as the output speed F1. Note that when the follow-up pressure ML becomes smaller than the deceleration distance D1 due to this acceleration, the deceleration is switched.
This deceleration process is the process (d) described later.

(d) shows a situation in which deceleration is performed when the command speed v1 is smaller than the output speed F(i-1) and the follow-up pressure ML is smaller than the deceleration distance D1. In this case, in order to decelerate and stop at the commanded position at a constant acceleration, at each sampling time, use the following distance and output speed at that time to find the acceleration at the next time, calculate the output speed, and output do. This is calculated as follows. In other words, when decelerating from the previous output speed F(i-1) with a constant acceleration until the output speed becomes zero, the acceleration ΔV is required to make the moving distance during this time equal to the current following distance. is given by using equation (2).

Therefore, in order to decelerate at a constant acceleration so that the output speed becomes zero at the point where the following distance becomes zero, that is, the point where the commanded position and the output position match, the next output speed F is given by . Therefore, the output speed F1 is calculated and output using equation (4) (step 512).

However, in order to absorb the approximation error in equation (3), Ll is ΔF
It should be determined in advance before the process of step S12 whether the output speed F
1-Li is output (step 513).

Note that during the above operation, step S4. S5゜36, S8
and 311, it is judged as "rYES" even in the case of -, and the process moves to the next step.

Due to the above-described operation, the operating characteristics of the acceleration/deceleration control device of the present invention are as shown in FIG. ), (Hb), the acceleration during acceleration and deceleration is constant. Further, even if the value of the command speed changes arbitrarily over time, the output speed quickly follows the designated acceleration without exceeding the value.

Also, as shown in Figure 5, even when a speed command (10) for moving at high speed over a short distance is input, the output speed will output an optimal waveform that accelerates and decelerates at the specified acceleration value as shown in (1). do.

In the above embodiment, the function of the output speed calculation section is to accelerate or decelerate the output speed with a constant acceleration, or to change the output speed as shown in FIG. A simple smoothing filter (
60) may be provided.

[Effects of the Invention] As explained above, the present invention calculates the following distance and deceleration distance from the command speed, acceleration, and output speed, uses these to judge acceleration/deceleration, and performs acceleration/deceleration at a constant acceleration. This configuration has the effect of providing an acceleration/deceleration control device 11 that maximizes the efficiency of the drive system and generates a fine and smooth speed waveform that enables high-speed, high-precision position control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the invention, FIG. 2 is a flowchart showing the control operation of an embodiment of the acceleration/deceleration control device of the invention, and FIG.
FIGS. 4 and 5 are waveform diagrams showing the operating characteristics of this invention. FIG. FIG. 7 is a configuration diagram of a conventional acceleration/deceleration control device, and FIGS. 8 and 9 are waveform diagrams showing operating characteristics of the conventional acceleration/deceleration control device. In the figure, (20) is a following distance calculation section (first calculation section), (21) is a deceleration distance calculation section (second calculation section), (
22) is an output speed calculation section (third calculation section). In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In an acceleration/deceleration control device that accelerates or decelerates the output speed to match the command speed at a fixed sampling period and outputs the calculation result, the difference between the command speed and the output speed is integrated and the following distance is calculated. a first calculation section that calculates the deceleration distance from the output speed and the acceleration command value;
An acceleration/deceleration control device comprising: a calculation unit; and a third calculation unit that calculates an output speed using the following distance, deceleration distance, and acceleration command value.