JP5211702B2 - Position control device - Google Patents

Description

The present invention relates to a position control device applied to NC machine tools and industrial machines, and more particularly to a position control device that drives a motor in synchronization with an activation signal input from the outside.

  A conventional position control device that drives a motor in synchronization with a start signal input from the outside has a sampling pulse generation circuit that generates a pulse having a constant period T inside, and the output pulse period T of the sampling pulse generation circuit. Each time an external signal from an external device is sampled, and when a predetermined external signal is turned on, the external signal is read at the first sampling immediately thereafter, and a driving device such as a predetermined positioning motor is installed at the second sampling. The positioning has been performed by starting up (see, for example, Patent Document 1).

  In addition, another position control device performs a position command calculation based on a motion command in synchronization with a timer interrupt at every fixed scan time and takes in a start command signal of a new motion command as an interrupt. The motion control processing is started and the timer is reset to shift the motion control execution timing. Thereafter, the motion control is executed in synchronization with the timer interrupt for each scan time (see, for example, Patent Document 2).

JP-A-5-333913 ([0002], FIG. 7) JP-A-11-224126 ([0005] to [0007], FIGS. 1 and 2)

In the conventional position control apparatus as described above, an external signal from an external device is sampled every period T. After the predetermined external signal is turned on, the external signal is read at the first sampling after that, the position command is generated, and the driving device such as the positioning motor is started. A delay time is generated from the time when the first sampling time is reached to the first sampling time immediately thereafter. The delay time becomes the above-mentioned period T at the maximum, and varies within the range. Since this delay time causes a delay in generating the position command, there is a problem that there is a variation in the time from when the external signal is input until the drive device is started.

  In another position control device, when the start command signal is input, the timer is reset and the motion control execution timing is shifted. Therefore, if this start command signal is being input when the motion control process is being executed, The motion control process is re-executed as a start command acceptance state immediately after the completion of the motion control process, or the motion control process being executed is canceled and the motion control process is newly executed as a start command acceptance state. There is a problem that it is necessary to control the execution of the motion control process.

The present invention has been made to solve such a problem, and it does not require execution control of a complicated motion control process, and the time from the input of an external start signal to the start of a driving device is reduced. A position control device capable of improving responsiveness by reducing variations is provided.

Position control apparatus according to the present invention, the a start signal detecting means for detecting the activation signal, the detection time of the start time storage means you stored as the start time of the activation signal, the position of the motor in a predetermined cycle Command generating means for generating a position command used for control, and motor control means for inputting the position command output from the command generating means and controlling the motor so that the motor position follows the position command. The command generation means delays the delay from the start time and the execution start time to the execution start time of the next processing cycle for generating the position command for each predetermined period after detecting the start signal. calculated as the time, based on the slow-being time, the activation signal to generate a position command to approximate to the ideal position command starting from the detected time points, process the generated position command next cycle It is configured to output to the motor control means as a position command definitive.

According to the position control device of the present invention, after detecting the activation signal, the delay until the execution start time of the processing cycle for generating the position command is calculated as the delay time from the activation time and the execution start time, and the delay time is calculated. The position command is generated so as to approximate the ideal position command starting from the time when the activation signal is detected, so that it is not necessary to shift the execution timing of the command generation means, and an ideal signal without delay with respect to the activation signal Directives can be generated. As a result, the execution control of the processing of the command generation means can be simplified, and variations in timing from when the activation signal is input until the motor starts operating can be eliminated.

Embodiment 1 FIG.
FIG. 1 shows the configuration of a position control apparatus according to Embodiment 1 of the present invention. 3 is a motor, 2 is a motor control means for servo-controlling the motor 3, 13 is a start signal detection means for detecting a start signal input from the outside, 12 is a clock signal input, and a detection signal from the start signal detection means 13 Is a start time storage means for storing the input time as a start time, and 11 is a command generation means for receiving a start time from the start time storage means 12 and outputting a position command to the motor control means 2 at a constant cycle Ts. .
FIG. 2 shows an internal configuration of the activation time storage unit 12. The activation time storage means 12 includes a counter 14 that counts clock signals and a latch circuit 15 that stores the value of the counter 14 at the timing of activation signal reception.

Next, the operation of the position control device according to this embodiment will be described. An activation signal is input to the activation signal detection means 13 from the outside. The activation signal detection unit 13 detects the input activation signal and outputs the detection signal to the activation time storage unit 12. In the start time storage means 12, a clock signal input from the outside is taken into the counter 14 and counted, and a counter value corresponding to the time is output to the latch circuit 15. The latch circuit 15 receives the count value of the counter 14, stores the counter value when the detection signal is input from the activation signal detection unit 13 as the activation time, and outputs the activation time to the command generation unit 11. The command generation means 11 performs an operation for generating a position command at a constant cycle Ts as shown in the timing chart of the control processing execution timing of the command generation means 11 and the motor control means 2 shown in FIG. Output to the motor control means 2. The command generation means 11 calculates a delay time from the start time output from the latch circuit 15 in the start time storage means 12 to the execution start time of the next processing cycle, and detects the start signal based on the delay time. A position command is generated so as to approximate an ideal position command starting from the time. The motor control unit 2 operates in synchronization with the command generation unit 11, and drives and controls the motor 3 based on the position command input from the command generation unit 11.

Here, in order to detect the time at which the activation signal is input with higher accuracy than that detected at the interval of the processing cycle Ts of the command generation unit 11, a clock signal having a cycle shorter than the processing cycle Ts of the command generation unit 11. Is input to the counter 14.

Next, generation of a position command based on the activation time will be described.
FIG. 4 shows a timing chart of the position control apparatus according to the present embodiment, where the upper stage shows the start signal, the middle stage shows the execution timing of the position command generation process of the command generation means 11, and the lower stage shows the position command to the motor control means 2. The position command Rs in FIG. 4 is an ideal position command starting from the time Ta when the activation signal is input, and is a position command having no delay time with respect to the activation time Ta, and is set in advance in the position command generation means. ing. R is a position command according to the present embodiment, and a black circle (●) on the position command R indicates a position command that the motor control unit receives from the command generation unit at that time.

The command generation means 11 outputs the initial position of the motor 3 as a position command until a start time Ta that is output from the latch circuit 15 in the start time storage means 12 and indicates that a start signal has been input. . As a result, the motor is stopped at the initial position until the start signal is input. Next, when the activation time Ta is input from the latch circuit 15, the position command generated during the processing cycle in which the activation time Ta is input is still an ideal position starting from the time when the activation signal is detected based on the delay time. A position command that approximates the command is not generated, and the initial position of the motor 3 is output as a position command at the execution start time T1 of the next processing cycle. In the position command generated during the processing cycle starting from T1 after the activation time Ta, a position command that coincides with the ideal position command without delay with respect to the activation time starting from the activation time Ta is generated, and further processing is performed. It outputs as a new position command to the motor 3 at the execution start time T2 of the cycle.

The position command starting from the activation time Ta is an ideal position command Rs that is not delayed with respect to the activation time Ta, and is set in advance in the position command generation means. For example, in the case of a position command with a constant acceleration, it is a function of the square of time. The value Rs (T) at time T is

Rs (T) = f (t) (1)

And Here, f (t) is an arbitrary function representing a command pattern of a position command starting from t = 0, and t is an elapsed time from the time Ta when the activation signal is input, that is, t = T−Ta. At this time, the value of Rs (T) at time Tn (n is a natural number) is

Rs (Tn) = f (Tn−Ta) = f (Tn−T1 + Td) (2)

It can be calculated with Here, Td is a delay time calculated by Td = T1-Ta. In the present embodiment, the command generation means 11 calculates the delay time Td using the activation time Ta stored in the activation time storage means 12 by the above formula, and based on this, the delay of the activation time Ta is delayed. No position command Rs (Tn) is calculated as described above.

Further, the command generation means 11 calculates a position command R that matches the position command Rs without delay with respect to the activation time Ta in each processing cycle. That is, since the position command calculated in the processing in the processing cycle starting from time Tn in the command generation unit 11 is passed to the motor control unit 2 at time T _{n + 1} , if this is R (T _{n + 1} ), R (T _{n + 1} ) _{n + 1} )

R (T _{n + 1} ) = Rs (T _{n + 1} ) = f (T _{n + 1} −T1 + Td) (3)

And this is output to the motor control means 2 at time _{Tn + 1} .

  As described above, the command generation unit 11 generates the position command R that matches the ideal position command Rs with no delay with respect to the activation time Ta after the time T2, and outputs the position command R to the motor control unit 2. Here, at time T1, the position command R (T1) received by the motor control means 2 does not coincide with the ideal position command Rs (T1) that is not delayed with respect to the activation time Ta. This is because R (T1) is generated in the processing cycle immediately before the start signal is input, and its value becomes the initial position of the motor. However, the position command R generated by the command generation means and the ideal position command Rs without delay do not coincide with each other only once immediately after the start signal is input, and immediately after the start signal is input. Therefore, since the difference between R (T1) and Rs (T1) is small, the influence can be ignored.

In the present embodiment, since the position command as described above is generated using the activation time Ta stored in the activation time storage means 12, the position starting from the time Ta when the activation signal is input as shown in FIG. It is possible to generate a command corresponding to the command, that is, the ideal position command starting from the time Ta. Thus, by generating a position command that starts from the time Ta and coincides with an ideal position command that is not delayed with respect to the activation signal, the timing from when the activation signal is input to when the motor starts operating is determined. Variations can be eliminated. Furthermore, in this embodiment, since it is not necessary to shift the execution timing of the command generation means, the execution control of the process in the command generation means can be simplified, and as a result, the processing speed can be increased and the responsiveness of the motor control is improved. To do.

Embodiment 2. FIG.
In the first embodiment, the case where the activation signal detection unit 13 and the activation time storage unit 12 are configured by hardware has been described. However, these functions can also be realized by software processing using a CPU. FIG. 5 shows the configuration of the position control apparatus according to this embodiment. In FIG. 5, 101 is a CPU with a built-in clock, 102 is an input interface for inputting a start signal, 103 is a memory for storing programs and data, and 104 is a communication interface for outputting a position command from the CPU 101 to the motor control means 2. It is. Here, FIG. 9 shows a case where a CPU with a built-in clock is used, but a clock signal may be input from the outside to the CPU 101 without a built-in clock.

  FIG. 6 shows a flowchart of processing executed by the CPU 101. Steps S2 to S4 show the processing of the activation signal detection means 13 and the activation time storage means 12 in the first embodiment, and steps S6 to S8 correspond to the processing of the command generation means 11 in the first embodiment. Here, the time corresponding to the period of the clock signal in the first embodiment is Ts ′, and the period Ts ′ is shorter than the processing period Ts for command generation. First, in step S1, it is determined whether or not Ts 'time has elapsed. If Ts' time has elapsed, the process proceeds to step S2. As a result, the processes in steps S2 to S4 are repeated at the cycle Ts'. On the other hand, if Ts' time has not elapsed in step S1, the process proceeds to step S5 to determine whether Ts time has elapsed. If the time Ts has elapsed, the process proceeds to step S6. If not, the process returns to step S1. Thereby, the process of step S6-S8 is repeated with the period Ts.

  In step S2, it is checked whether an activation signal is input. When the activation signal is not input, the process returns to step S1, and when it is input, the process proceeds to step S3. In step S3, it is determined whether or not the activation time is already stored. If the activation time is not stored, the activation signal is inputted for the first time this time, and the current time is stored in memory 103 as the activation time in step S4. If the activation time is stored in step S3, the generation of the position command has already been started, so nothing is done and the process returns to step S1.

  In step S6, it is checked whether the activation time is stored. If the activation time is not stored, the activation signal has not yet been input, and the initial position of the motor 3 is output as a position command to the motor control means 2 in step S8. If the start time is stored, the process proceeds to step S7, where a calculation for generating a position command is performed, and the generated position command is output to the motor control means 2.

FIG. 7 is a timing chart of the position control device according to the second embodiment. The first stage from the top is the start signal, the second stage from the top is the start signal detection execution timing, and the third stage from the top is the position command generation. The execution timing, the fourth level from the top, indicates a position command to the motor control means 2. Rs indicates a position command starting from the time Ta when the activation signal is input, that is, an ideal position command starting from the time when the activation signal is detected, and R indicates a position command according to the present embodiment.

The CPU 101 detects the activation signal at a cycle Ts ′ shorter than the processing cycle Ts of the command generation unit 11 as a function corresponding to a part of the functions of the activation signal detection unit 13 and the activation time storage unit 12 in the first embodiment. When the activation signal is input, the time is stored in the memory 103 corresponding to the activation time storage unit 12. Further, as a function corresponding to the command generation unit 11 in the first embodiment, the CPU 101 calculates a delay time from the start time stored in the memory 103 to the execution start time of the next position command generation processing cycle, and the start time In the position command after the position command immediately after the position command, the position command R is generated at regular intervals Ts so as to approximate to the ideal position command Rs starting from the time when the activation signal is detected based on the delay time.

In the present embodiment, the CPU 101 detects the activation signal at a cycle shorter than the command generation processing cycle and stores the activation time Ta in the memory 103, and the next position command is generated from the activation time in the same manner as in the first embodiment. The delay time until the execution start time of the processing cycle is calculated, and a position command that starts from the time Ta and matches the ideal position command with no delay with respect to the start signal is generated. It is possible to eliminate variations in timing until the operation starts. Furthermore, since it is not necessary to shift the execution timing of command generation, the execution control of processing in command generation can be simplified. As a result, the processing speed can be increased, and the responsiveness of motor control is improved.

Embodiment 3 FIG.
FIG. 8 shows the configuration of the position control apparatus according to this embodiment. 1 is a command generation means for generating a position command in response to an activation signal from the outside, and 21 is a correction of the position command generated by the position command generation means 1 based on the activation time stored in the activation time storage means 12. It is the correction | amendment means to output.

  The command generation means 1 in the present embodiment receives a signal indicating whether or not a start signal has been input from the start signal detection means 13 and starts generating a position command based on this signal. Therefore, unlike the command generation unit 11 in the first embodiment and the position command generation in the CPU 101 in the second embodiment, the position command is generated without using the startup time stored in the startup time storage unit 12 or the memory 103. Is configured to do.

FIG. 9 shows an internal configuration example of the correction means 21. Reference numeral 24 denotes a delay time calculation means for obtaining a delay time Td from the start time at which the start signal is input to the execution start time of the next processing cycle in the command generation means 1, and 25 differentiates the position command obtained by the command generation means 1. A differentiator 23 for multiplying the output of the differentiator 25 and the output of the delay time calculating means 24, and 22 an adder for adding the output of the command generating means 1 and the output of the multiplier 23. .

In the position control apparatus configured as described above, the activation signal detection unit 13 and the activation time storage unit 12 detect the activation signal and store the activation time in the same manner as in the first embodiment. FIG. 10 shows a timing chart of the position control device of the present embodiment. In FIG. 10, the upper stage shows the start signal, the middle stage shows the execution timing of the command generation means 1, and the lower stage shows the position command. The position command Rs is a position command starting from the time Ta at which the activation signal is input, and is an ideal position command without delay with respect to the activation signal, and is set in the command generation means 1 in advance. The position command Ro is a position command that is calculated and generated by the command generation unit 1 at a constant cycle Ts, and is a position starting from T1 that is the execution timing of the command generation unit 1 immediately after the start signal is input. The command is a position command delayed by Td with respect to Rs. Further, R is a correction position command output by the correction means 21.

Since the position command Ro generated by the command generation means 1 is delayed by Td with respect to the position command Rs without delay, the relationship between Ro and Rs at time T is expressed as in Expression (4). be able to.

このＲｏ（Ｔ＋Ｔｄ）に対してテイラー展開を行うと式（５）の多項式で表現できる。

When Taylor expansion is performed on this Ro (T + Td), it can be expressed by the polynomial of equation (5).

そして、式（５）の３項目以降の項は影響が小さいため、これらを無視すると式（６）のように近似することができる。

Since terms after the third item in equation (5) have little influence, if these are ignored, they can be approximated as in equation (6).

In FIG. 9 showing the configuration of the correction means 21, the position command from the command generation means is Ro (T), the output of the differentiator 25 is dRo (T) / dT, and the output of the delay time calculation means is Td. When the adder 22 adds the output of the device 23 to the position command Ro (T) from the command generating means, the output coincides with the rightmost side of the equation (6). That is, the correction means 21 is configured to perform the calculation of the expression (6), and generates and outputs a corrected position command that approximates the ideal position command Rs that starts from the start time Ta and has no delay with respect to the start time. To do.

  R in FIG. 10 indicates the output of the correction means 21, and a position command that substantially matches the ideal position command Rs without delay with respect to the activation time Ta is obtained. As described above, the correction unit 21 corrects the delay of the position command generated by the command generation unit 1 based on the delay time Td, and the position command at the time Ta after the position command immediately after the position command immediately after the start time. The correction position command that starts with the start signal and matches the ideal position command without delay is generated and output to the motor control means 2. The motor control means 2 inputs this as a position command and drives and controls the motor 3.

According to the present embodiment, since the delay of the position command due to the delay time Td is corrected by the correcting unit 21 until the generation of the position command is started by the command generating unit 1 after the start signal is input, the start time Ta Position command, i.e., a corrected position command that matches the ideal position command without delay with respect to the start signal, and the timing from when the start signal is input to when the motor starts operating can be generated. Variations can be eliminated. Furthermore, in this embodiment, since it is not necessary to shift the execution timing of the command generation unit, the execution control of the process in the command generation unit is not complicated, and as a result, the process can be speeded up and the responsiveness of the motor control is improved. improves.

The position control device according to the present invention is suitable for use as a position control device that performs position control in synchronization with an activation signal input from the outside.

1 is a configuration diagram of a position control device according to Embodiment 1. FIG. 4 is a configuration diagram of a start time storage unit of the position control device according to Embodiment 1. FIG. 4 is a timing chart of control processing of a command generation unit and a motor control unit of the position control device according to the first embodiment. 3 is a timing chart of the position control device according to the first embodiment. FIG. 4 is a configuration diagram of a position control device according to a second embodiment. 10 is a flowchart showing processing in a CPU of the position control device according to the second embodiment. 6 is a timing chart of the position control device according to the second embodiment. FIG. 6 is a configuration diagram of a position control device according to a third embodiment. FIG. 6 is a configuration diagram of correction means of a position control device according to Embodiment 3. 10 is a timing chart of the position control device according to the third embodiment.

Explanation of symbols

1, 11 Command generation means, 2 motor control means, 3 motor, 12 start time storage means, 13 start signal detection means, 14 counter, 15 latch circuit, 21 correction means, 22 adder, 23 multiplier, 24 delay time calculation Means, 25 differentiator, 101 CPU.

Claims (4)

In the position control device that controls the position of the motor in synchronization with the start signal from the outside,
An activation signal detecting means for detecting the activation signal;
And Starting time storage means you store the detection time of the activation signal as a start time,
Command generating means for generating a position command used for position control of the motor at regular intervals;
Motor control means for inputting the position command output from the command generation means and controlling the motor so that the motor position follows the position command;
It said command generating means, after detecting the activation signal, for each said predetermined period, the position delayed until the execution start time of the next processing cycle for generating the command, the start time and start time from the delay time Based on the delay time, a position command is generated so as to approximate an ideal position command starting from the time when the activation signal is detected, and the generated position command is used as a position command in the next processing cycle to control the motor. A position control device that outputs to the means . In the position control device that controls the position of the motor in synchronization with the start signal from the outside,
An activation signal detecting means for detecting the activation signal;
And Starting time storage means you store the detection time of the activation signal as a start time,
Command generation means for checking the presence or absence of the activation signal at regular intervals and generating a position command used for position control of the motor;
After detecting the activation signal, the delay until the execution start time of the next processing cycle for generating the position command is calculated as a delay time from the activation time and the execution start time for each fixed cycle , and the position command The position command input from the generating means is corrected to generate a position command corrected to approximate the ideal position command starting from the time when the activation signal is detected, and the corrected position command is processed in the next process. Correction means for outputting as a position command in a cycle ;
A position control apparatus comprising: a motor control unit that inputs a corrected position command output from the correction unit and controls the motor so as to follow the position command in which the motor position is corrected. The correction means includes a delay time calculation means for obtaining a delay time from the start time to the execution start time of the next processing cycle for generating a position command used for motor position control in the command generation means;
A differentiator for differentiating the position command generated by the command generation means;
A multiplier for multiplying the output of the differentiator by the output of the delay time calculating means;
An adder for adding the output of the multiplier to the position command input from the position command generation means,
The position control apparatus according to claim 2, wherein a result obtained by the addition by the adder is output to the motor control unit. 4. The start time storage means determines input of a detection signal from the start signal detection means in a cycle shorter than a processing cycle for generating a position command by the position command means . Item 1. The position control device according to item 1 .

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