JPH02238503A - Digital servo controller - Google Patents

Abstract

PURPOSE:To prevent the wrong rewriting of the contents of a shared memory by controlling the writing tasks to a host computer to an area for a control constant and an area for a control variable of the shared memory. CONSTITUTION:A host processor 1 sets the resets flip-flops 5-1 and 5-2. A shared memory 6 is divided into areas A1 - A3 which are assigned to an area to write the commands given from a host computer, a control constant area for the feedback gain, the acceleration of a shift state, the lowest speed, etc., and a control variable area for the control deviation, the differential value, the integral value, etc., respectively. Then the writing jobs are inhibited to the area A2 from the processor 1 as long as the flip-flop 5-1 is reset. In the same way, writing job is inhibited to the area A3 from the processor 1 when the flip-flop 5-2 is reset. Thus the wrong change is never given to the control constant and the control variable.

Description

[Detailed Description of the Invention] [Summary] Regarding a digital servo control device for positioning control or speed control of mechanical parts of robots and NC machine tools, the content of the shared memory may be incorrectly read due to host computer hugging, etc. For the purpose of preventing rewriting, a shared memory is placed between the host computer and the control computer, and the first flag is used to prevent the host computer from writing to the area where control constants and control variables are placed in the shared area. and a second flag.

[Field of Application in Industry-12] The present invention relates to a digital servo control device for positioning control or speed control of a mechanical part of a robot, NC machine tool, etc.

These servo control devices are controlled by digital servo control using software using a computer in order to reduce the size of the device, improve reliability, and facilitate adjustment. In that case, servo control needs to be performed in real time, so a control computer that performs simple but high-speed calculations and a control computer that performs complex processing that does not require high speed, such as console display and file management, are required. The processing is shared with the host computer.

[Conventional technology]

When processing is divided between two computers, data must be exchanged between the host computer and the control computer.

The host computer sends commands such as constant settings and movement commands to the control computer, and the control computer sends responses such as movement completion and errors to the host computer. Conventionally, a buffer for commands and a buffer for responses were provided, but in order to avoid the need to repeatedly exchange command responses when there are many constants to be set or when the host computer monitors the internal status of the control computer, A shared memory method is used in which the computer's memory is visible to the host computer.

[Problem to be solved by the invention]

In the case of shared memory, the status of the control computer can be easily monitored or set from the host computer, but on the other hand, if the host computer is hacked and the contents of the shared memory are accidentally rewritten, the control system may behave in unpredictable ways. In the worst case, it may run out of control and damage the mechanism.

The present invention was created in view of this point, and it is an object of the present invention to provide a digital servo control device that prevents the contents of a shared memory from being erroneously rewritten due to hugging of a host computer, etc. .

[Means to solve the problem] There are three types of shared memory areas: AI Always writable A2 Writable only when the first flag is set A3 Writable only when the second flag is set Area A1 is an area for writing commands from the host computer, area 2 is an area for control constants such as feedhug gain, acceleration during movement, minimum speed, etc., area 3
into the control variable domain such as control deviation, differential quantity, integral quantity, etc.

[Effect]

When starting up after turning on the power or adjusting the servo system, set the first flag so that the control constants can be easily set or changed, and when the mechanism is operating, lower the first flag and accidentally set the control constants. Avoid rewriting the . Also, the second flag is generally lowered to prevent the host computer from changing the control variables without permission.
Only in special cases, such as when debugging a control computer, the second flag is set so that control variables can be set or changed.

〔Example〕

FIG. 2 is a block diagram of one embodiment of the present invention.

In the figure, 1 is a host processor, 2 is a host memory, 3 is a console, 4 is a disk device, 5-1 and 5-2 are Flinop flops, 6 is a shared memory, 7 is a control processor, and 8 is a 9 is a D/A converter, 10 is a power amplifier, 1l is an encoder, 12 is a motor, 13 is a mechanism section, and AI to A3 are divided areas of the shared memory.

Host processor 1 can set/reset flip-flop 5-1, and similarly can set/reset flip-flop 5-2. The shared memory 6 is divided into areas AI and A2A3, and if the flip-flop 5-1 is reset, the host processor 1 cannot write to the area A2. When the flip-flop 5-2 is reset, the area A3 cannot be written to by the processor 1.

The control processor 7 counts pulse signals from the rotary encoder 11, which is a position sensor of the mechanism section 13, reads this as position information y, calculates it according to the flowchart shown in FIG. 7, and converts the manipulated variable U into D/ Output to A converter 9.

The output voltage of the D/A converter 9 is sent to the motor 12 via the power amplifier 10 to rotate the motor 12 and move the mechanism section 13.

FIG. 3 is a block diagram of the control system. In the same figure, 1
4 is a function generator, 15 is a PID compensator, 16 is a controlled object (m. structure), r is a target position, r is a command position, e is a position deviation, U is an operation amount, and y is a current position. It shows.

As shown in FIG. 3, when a target position r, is given to the function generator 14, a command position r is generated, and feed hack control is performed so that the deviation e from the current position W'/ is small. The function generator 14 generates a command speed r and a command speed V, as shown in FIG.

FIG. 4 is a diagram showing the relationship between the shared memory and the bus in the present invention. In the same figure, 17 and 18 are OR circuits, 19
and 20 are AND circuits, 21 to 23 are OR circuits, 24
25 is an inverting circuit, 25 is an OR circuit, 26 is a decoder, 27 is a lotus contention avoidance circuit, and 28 is a decoder.

The decoder 26 decodes the address on the host CPtJ bus and generates a chip select signal. Is the decoder 28 controlled? It decodes the address on the 111 CPU bus and generates the chip select 1 signal. When a shared memory access request from the host processor 1 and a shared memory access request from the control processor 7 conflict, the bus conflict avoidance circuit 27 grants bus usage rights to one of the request sources. It is something.

The host processor 1 can always read/write the area A1 of the shared memory 6. host processor 1
can always read/write the area A2 of the shared memory 6 when the flip-flop 5-1 is set, but when the flip-flop 5-1 is reset, the area A2 can be read/written. Although data in A2 can be read, data cannot be written in area A2.

Similarly, host processor 1 performs flip-flop? When flip-flop 5-2 is set, area A3 of shared memory 6 can be read/written, but when flip-flop 5-2 is reset, area A3 can be read/written.
Although it is possible to read the data in area A3, it is not possible to write data in area A3. The control pro sensor 7 is
Areas AI, A2, and A3 of the shared memory can always be read/written.

FIG. 5 is a diagram showing an example of a shared memory map.

Command names, command parameters, etc. are stored in area A1 of the shared memory.

The area Δ2 of the shared memory stores the proportional gain Kp, the integral gain K, the differential gain Ka, and the maximum number of manipulated variables U■. , the manipulated variable U is the maximum value U0. Tolerance value NSaL+ for the number of times i exceeded
Value R near for indicating the vicinity area of the target position rf
, Maximum speed ■. X. Control constants such as the minimum speed value ■■, A, and set acceleration A are stored.

Area A3 of the shared memory stores the current position y, position deviation e,
Differential value of deviation d, integral value of deviation W, positional deviation ebfr one sampling before, manipulated variable U, manipulated variable is maximum value U ma
Control variables such as the number of times x has been exceeded i, target position r, command position Jr, command speed V, and command acceleration a are stored.

FIG. 7 is a diagram showing an example of control flowchart 1. When the control computer receives a command, it interprets the command. Then, processing from ■ to 0 is performed in synchronization with the sampling clock. It should be noted that ■ to ■ are the processes of the PID compensator, and ■ to [phase] are the processes of the function generator.

■ Input y from the counter.

■ Calculate the manipulated variable U by PID calculation, and calculate the deviation e by
Write to bfr.

■ Check and record whether the absolute value of the manipulated variable U is less than or equal to tJmax. If yes, proceed to ■; if NO, proceed to ■.

■ Set i to O.

■ When U is positive, set it as +U,,X, and when U is negative, set it as -U II a K. Add 1 to i.

=9? Check whether i is less than or equal to Ns■. If Yes, proceed to ■; if No, display an error.

■ Output U to the D/A converter.

■ Update the command position r and command speed V.

(2) Check whether the absolute value of rr -r is less than or equal to r nQar. If Yes, proceed to @; if No, proceed to [
Proceed to phase].

[Phase] Check whether the absolute value of (1) is greater than or equal to V max. If YES, proceed to ■; if NO, return to ■.

■ Set a to 0 and ■ to ±Vmax. Return to ■.

@ When V is positive, set it to -A, and when ■ is negative, set it to +8.

■ The absolute value of V is v. , 7 or less.

If YES, proceed to 0; if NO, return to ■.

Let O a be Q, v be O, and r be r. Wait for next command.

FIG. 8 is a diagram showing an outline of processing by the host processor. After turning on the power, the host processor writes control constants into area A2 of the shared memory.

■ Reset FF1.

■ Repeat the process of reading control variables such as the current position from area A3 of the shared memory and displaying them on the console.

On the other hand, when a command is input from the console keyboard, an interrupt occurs. ■ Check whether the command is a servo adjustment command. If Yes, proceed to ■; if No, proceed to ■.

■ Set F'FI.

■ Process the adjustment command and rewrite the control constants in area A2 of the shared memory.

■Reset the FFI and return with an interrupt.

■ Determine whether a command is a debug command. Y
If es, proceed to ■; if NO, proceed to @.

■ Set FF2.

[Phase] Process debug commands. At this time, if necessary, the control variables in area A3 of the shared memory are rewritten.

@Reset FF2 and return with an interrupt.

■If it is a general command that is neither an adjustment command nor a debunk command, it will process the command and return with an interrupt. General commands include sending a movement command to a control processor, commands for managing files, and the like.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, control constants and control variables can be easily changed when adjusting or dehacking a control system, and control constants and control variables can be easily changed during operation of the control system. This improves reliability.

6 is a diagram showing an example of the command position r and command speed V generated by the function generator, FIG. 7 is a diagram showing an example of a control flowchart, and FIG. 8 is a diagram showing the processing of the host processor. It is a figure showing a flow.

DESCRIPTION OF SYMBOLS 1... Host processor, 2... Memory for host, 3... Console, 4... Disk unit, 5-1
and 52...flimp flop, 6...shared memory, 7...control processor, 8...counter, 9...
...D/A converter, 10...power amplifier, 1
DESCRIPTION OF SYMBOLS 1... Encoder, 12... Motor, 13... Mechanism part, A1 to A3... Divided area of shared memory.

Patent applicant: Fujitsu Limited Representative Patent Attorney: Shiro Kyotani

[Brief explanation of drawings]

Claims (1)

[Scope of Claims] A digital servo control device having a shared memory that can be read and written by both a host computer and a control computer, which has a first flag and a second flag that can be set and reset by the host computer, and has a shared memory that can be set and reset by the host computer. Part of memory area A2
When the first flag is reset, writing from the host computer is prohibited, and writing to another part of the shared memory area A3 is prohibited when the second flag is reset, and the control computer The control constants for the servo control performed by the controller are stored in area A2, and the control variables are stored in area A3.The first flag is set when starting up after turning on the power and when adjusting the servo system, and when debugging the control computer. A digital servo control device characterized by setting a second flag and resetting the first flag and the second flag at other times.