JP5889104B2 - Command generator for positioning control - Google Patents

Description

  The present invention relates to a positioning control command generation device that generates a command value that serves as a target reference signal during positioning control when positioning control of a mechanical load using a motor such as a servomotor.

  Typical examples of positioning control include servo motors with encoders, servo amplifiers that control servo motors using encoder information, and motion controllers that give servo amplifiers command values for positioning control. An example of using a command value generator is given. The encoder has integer value resolution (for example, outputs 100000 pulses per motor rotation), and the motion controller gives the servo amplifier a command value that takes an integer value every predetermined period according to the desired amount of movement. The servo amplifier performs a process of calculating a current to be supplied to the servo motor by performing feedback control or the like so that the position of the encoder follows the command value, and supplying the current to the servo motor.

  During the positioning control, the motion controller uses a command value (speed that is a differential signal of position command value and acceleration that is a differential signal of velocity) in a desired shape and with no deviation of one pulse with respect to a desired movement amount. A value needs to be generated. In addition, in order not to excite mechanical vibration during positioning control, it is required to set not only simple triangles and trapezoids but also acceleration time, deceleration time, and jerk speed as the shape of the command value. .

  As techniques for generating such command values for positioning control, for example, Patent Documents 1 to 3 shown below are disclosed. In Patent Document 1, a deceleration start position is input in advance, and an equation for calculating a command value for each mode such as an acceleration increase mode, a constant acceleration mode, an acceleration decrease mode, a constant speed mode, and the like is prepared in advance. A technique for making a calculation formula corresponding to the deceleration mode when the deceleration start position is reached is disclosed. Patent Document 2 discloses that S-shaped acceleration / deceleration is realized using a moving average filter. In Patent Document 3, the movement distance necessary for deceleration is calculated by using a movement distance (speed ^ 2 / acceleration / 2) for deceleration and stopping at a constant acceleration and a correction coefficient calculated based on jerk time information. It is disclosed to calculate the position command for the deceleration stop by calculating the product, determining the timing for starting the deceleration stop based on the calculated movement amount necessary for the deceleration.

JP-A-2-121005 JP 2008-171230 A International Publication No. 2010/125958

  However, according to the above-described conventional technique, for example, the technique of Patent Document 1 has a problem that it takes time to input a deceleration start position in advance. Furthermore, if the deceleration start position is set inappropriately, there is a problem that the shape of the command value during the deceleration operation does not follow the desired shape.

  Furthermore, in the technique of Patent Document 2, moving average processing is performed. However, in moving average processing, it is necessary to prepare a buffer memory in proportion to the moving average time. There was a problem that had to be prepared.

  Patent Document 3 discloses that the moving distance necessary for decelerating and stopping at a constant acceleration is speed 2 / acceleration / 2. Considering that the command value is generated using the CPU mounted on the motion controller, the command value is usually generated every certain control cycle (for example, every 1 ms). For example, the control cycle is 1 ms, and the deceleration is performed. When the starting speed is 100 pulses / ms, the acceleration during deceleration is 10 pulses / ms ^ 2, and the vehicle decelerates at a constant acceleration, the movement amount necessary for deceleration is calculated by applying speed ^ 2 / acceleration / 2. 500 pulses. However, when calculating the speed during actual deceleration operation, the value 10 corresponding to the acceleration during deceleration is subtracted from 100, 90, 80, ..., 20, 10 and the speed of 100 pulses / ms every 1 ms. As a result, the speed at the time of deceleration is calculated, and further, when all of these are summed to calculate the amount of movement required for deceleration, 100 + 90 + 80 +... + 20 + 10 = 550 pulses. This means that an error has occurred in the above calculation formula. When decelerating and stopping at a constant acceleration, the speed decreases linearly. At this time, the deceleration time becomes speed / acceleration, and the travel required for deceleration is speed x deceleration time / 2 = speed ^ 2 / acceleration / 2. Utilizing relationships. Although this calculation formula is an accurate calculation formula for continuous time, an error occurs when it is applied when calculating a command value for each predetermined period (every discrete time). Even when the correction coefficient is applied, the calculation is performed on the assumption of continuous time, so that an error occurs. When an error occurs, the start of deceleration cannot be started at an appropriate timing, which causes a problem that the shape of the command value is disturbed.

  The present invention has been made in view of the above, and it can be applied to complicated command values such as S-shaped commands that have different jerk times at the start of acceleration, at the end of acceleration, at the start of deceleration, and at the end of deceleration. Another object of the present invention is to provide a positioning control command generation device that can automatically and accurately calculate the amount of movement required for deceleration and stop and that can be mounted even with a small computer load such as a memory.

  In order to solve the above-described problem and achieve the object, the present invention includes a position command calculation unit that calculates a position command value based on elapsed time, speed, acceleration time, and jerk time, and during acceleration operation, Position calculated by the position command calculation unit using the elapsed time as the elapsed time for each predetermined period from the start of the position command, the speed as the target speed, and the jerk time as the jerk time during the acceleration operation Position command value that is calculated by the position command calculation unit that outputs a command value at the time of acceleration, and the elapsed time and the acceleration time are set as the deceleration time, and the jerk time is set as the jerk time during deceleration. By comparing the remaining distance, which is the difference between the target movement amount and the position command value, with the movement amount necessary for the deceleration stop. Start deceleration stop operation If the deceleration start timing determination unit and the deceleration start timing determination unit determine whether to start the deceleration stop operation, the position command value of the deceleration stop operation is calculated using the calculation result of the position command calculation unit. And a deceleration stop control unit for calculating and outputting.

  According to the present invention, there is an effect of obtaining a positioning control command generation device that accurately generates a command value so as to have a specified shape.

FIG. 1 is a graph showing the change over time of the command value obtained by the first embodiment. FIG. 2 is a block diagram for explaining an example of the configuration of the positioning control command generating device, the servo amplifier, the servo motor, and the mechanical load according to the embodiment. FIG. 3 is a flowchart for explaining in detail the flow of processing in which the positioning control command generation device according to the first embodiment generates a command value. FIG. 4 is a flowchart for explaining in detail the flow of the deceleration stop process in the first embodiment. FIG. 5 is a graph showing the change over time of the command value obtained by the second embodiment. FIG. 6 is a flowchart for explaining in detail the flow of processing in which the positioning control command generation device according to the second embodiment generates a command value. FIG. 7 is a flowchart for explaining in detail the procedure for calculating the position command value at the time of speed change in the second embodiment. FIG. 8 is a diagram showing a speed waveform and a speed change request at the time of speed change in the second embodiment. FIG. 9 is a block diagram of a configuration of the positioning control command generation device according to the first embodiment. FIG. 10 is a block diagram of a configuration of the positioning control command generation device according to the second embodiment.

  Embodiments of a positioning control command generating apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
As an example of the positioning control command value, a case will be described in which a command value having a trapezoidal acceleration shape and an S-shaped velocity is generated as shown in FIG. The command values shown in FIG. 1 are the amount of movement, acceleration time, deceleration time, target speed, jerk time 1 which is the time from acceleration to peak acceleration during acceleration, and peak acceleration during acceleration. Jerk time 2 which is time to reach 0 from acceleration, jerk time 3 which is time until acceleration reaches peak acceleration from 0 at deceleration, acceleration reaches 0 from peak acceleration at deceleration Is generated based on the information of jerk time 4 that is the time until.

  FIG. 2 is a block diagram for explaining an example of the configuration of the positioning control command generating device 1, the servo amplifier 3, the servo motor 5, and the mechanical load 8 according to the present embodiment. A positioning control command generation device 1 such as a motion controller outputs a position command value 2 for positioning control to the servo amplifier 3. Typically, the positioning control command generator 1 is realized by mounting a procedure or algorithm for generating the position command value 2 on a CPU, FPGA, or the like. FIG. 9 is a block diagram showing a configuration of the positioning control command generating device 1. The positioning control command generation device 1 includes a position command calculation unit 11, an acceleration position command calculation unit 12, a stop movement amount calculation unit 13, a deceleration start timing determination unit 14, and a deceleration stop control unit 15. The function of each part will be described below.

  The servo amplifier 3 controls the servo motor 5, and the encoder 6 attached to the servo motor 5 outputs the position 7 of the servo motor 5 to the servo amplifier 3. For example, the encoder 6 generates 100,000 pulses per rotation of the servo motor 5 and outputs a pulse corresponding to the rotational position of the servo motor 5. The servo amplifier 3 supplies the servo motor 5 with a current 4 for generating torque for performing a positioning operation so that the position 7 of the servo motor 5 follows the position command value 2. In the servo amplifier 3, feedback control or the like is performed so that the position 7 of the servo motor 5 follows the position command value 2. The servo motor 5 controlled in this way drives the mechanical load 8.

  FIG. 3 is a flowchart for explaining in detail the flow of processing for the positioning control command generator 1 shown in FIGS. 2 and 9 to generate the position command value 2. In step S1, target movement amount D, target (top) speed v, acceleration time constant Ta, deceleration time constant Td, jerk time ratio 1 (rd1), jerk time ratio 2 (rd2), jerk speed time The ratio 3 (rd3) and the jerk time ratio 4 (rd4) are respectively input to the positioning control command generator 1.

  Here, the acceleration time constant Ta is a parameter representing the time required for the servo motor 5 to accelerate from the speed 0 to the motor rated speed, and is a parameter for calculating the acceleration time. The deceleration time constant Td is a parameter representing the time required when the servo motor 5 decelerates from the motor rated speed to the speed 0, and is a parameter for calculating the deceleration time. Jerk speed time ratio 1 is a parameter representing the ratio of the time from acceleration 0 to peak acceleration 1 in the acceleration time, and jerk time ratio 2 is the time in acceleration time from peak acceleration 1 to acceleration 0. A parameter representing a ratio, jerk time ratio 3 is a parameter representing a ratio of time taken for acceleration to reach peak acceleration 2 in deceleration time, and jerk time ratio 4 is a time for reaching acceleration 0 from peak acceleration 2 This parameter represents the ratio of the deceleration time. Accordingly, the jerk speed time ratios 1, 2, 3, and 4 are all designated with a value of 0 to 100%. Further, the target speed v is given as an amount (for example, 10,000 pulses / control cycle) in which the position increases per control cycle (predetermined cycle). Further, in the following description, it is assumed that the speed represents the amount by which the position per control cycle increases, and the acceleration represents the amount by which the speed increases per control cycle.

  In step S2, variables used for subsequent processing are initialized. That is, i = 1, R = D, and X [0] = 0. Here, i represents an elapsed time after the output of the position command value 2 is started, and i increases by +1 for each control period. X [i] represents a position command value at time i, and i = 0, that is, a position before the output of the position command value 2 is started. As will be described in detail later, R represents a remaining distance that is not sufficient for the target movement amount D in the current control time. R = D corresponds to the position command being 0 before the command is started.

In step S3, acceleration time ta, jerk time 1 (d1), jerk from target speed v, acceleration time constant Ta, jerk time ratio 1 (rd1), and jerk time ratio 2 (rd2). Speed time 2 (d2) is calculated. In particular,
ta = (v × Ta) / Vr
d1 = ( t a × rd1) / 100
d2 = ( t a × rd2) / 100
Calculate according to Here, Vr represents the rated speed of the motor, and is a value uniquely determined if the motor to be used is determined. The acceleration time ta and jerk time 1 (d1) and 2 (d2) are both calculated as integers (values corresponding to how many times the control period corresponds). In addition, division (division) when calculating the above is performed by rounding off, and in the following description, when division occurs, calculation is performed by rounding off.

In step S4, it is determined whether the elapsed time i is equal to or shorter than the acceleration time ta. If the elapsed time i is less than or equal to the acceleration time ta (step S4: Yes), in step S5, depending on the time i (i = 1, 2, 3,...) That has elapsed since the command was started. Then, the position command calculation unit 11 calculates a position command value candidate Y by Y = f (i, v, ta, d1, d2). However, the calculation formula f (i, v, ta, d1, d2) of the position command value during the acceleration operation is defined as the following formula (1). After step S5, the process proceeds to step S7.

  Further, if i> ta in step S4 (step S4: No), that is, if the elapsed time i has passed the acceleration time ta, a constant speed operation is performed. Using the value X [i−1], the position command value candidate value Y is calculated as Y = X [i−1] + v. After step S6, the process proceeds to step S7.

In step S7, the stop movement amount calculation unit 13 calculates a predicted speed Vp that is a speed when the position command value candidate Y becomes a position command value at time i by Vp = Y−X [i−1]. . Further, the deceleration time td required to decelerate and stop from the deceleration is calculated from the deceleration time constant Td and the predicted speed Vp as follows.
td = (Td × Vp) / Vr
When the deceleration time td is calculated, d3 which is jerk time 3 and d4 which is jerk time 4 are calculated as follows.
d3 = (td × rd3) / 100
d4 = (td × rd4) / 100
Here, the deceleration time td and jerk speed times 3 (d3) and 4 (d4) are all calculated as integer data.

In step S8, v = Vp, ta = td, d1 = d4, d2 = d3 with respect to the predicted speed Vp, deceleration time td, jerk time 3 d3, and jerk time 4 d4 calculated in step S7. Further, by substituting i = td into the above equation (1), the position command calculation unit 11 calculates the movement amount Dd necessary for deceleration stop. That is,
Dd = f (td, Vp, td, d4, d3)
Is calculated. Thereby, the amount of movement required for deceleration stop can be calculated accurately. The stop movement amount calculation unit 13 passes this to the deceleration start timing determination unit 14 as a movement amount Dd necessary for deceleration stop.

  In step S9, the deceleration start timing determination unit 14 compares the movement distance Dd required for deceleration calculated in step S8 with the remaining distance R. As a result of the comparison, if the remaining distance R is larger than the movement amount Dd required for deceleration stop (step S9: Yes), the process proceeds to step S10. In step S <b> 10, the acceleration position command calculation unit 12 sets the position command value X [i] = Y at time i and outputs it to the servo amplifier 3. In step S11, the remaining distance R is updated by R = D−X [i]. Also, i is incremented, i.e., i = i + 1. Further, the predicted speed Vp, deceleration time td, jerk time 3 d3, jerk time 4 d4, and travel amount Dd required for deceleration stop calculated in step S7 are Vmp = Vp, tmd, respectively. = Td, dm3 = d3, dm4 = d4, and Dmd = Dd. Thereafter, step S4 and subsequent steps are executed again in the next control cycle.

  In step S9, if the deceleration start timing determination unit 14 determines that the remaining distance R is smaller than the movement amount Dd required for deceleration (step S9: No), the process proceeds to the deceleration stop process in step S12 and the process is completed. . FIG. 4 is a flowchart for explaining the details of calculating the position command value at the time of deceleration stop, that is, deceleration stop of step S12. The deceleration stop process of step S12, that is, the flowchart of FIG.

  In step S101 of FIG. 4, the corrected remaining distance H at the time of deceleration stop is calculated from the difference between the remaining distance R and the movement amount Dmd necessary for deceleration stop. That is, H = R−Dmd. Note that Dmd used here is the Dmd stored when it is first determined in step S9 that the remaining distance R is smaller than the movement amount Dd required for deceleration, that is, Dd in the previous control cycle, so H is negative. Don't be.

  In step S102, variables used for later processing are initialized. That is, j = 1 and Vold = Vmp. Here, j represents the time since the start of the deceleration operation, and Vold is a variable representing the speed in the previous control cycle.

In step S103, v = Vmp, ta = tmd, d2 = dm3, d1 = dm4 in the equation (1), and the position command calculation unit 11 performs Y1 = f (tmd−j + 1, Vmp, tmd, dm4, dm3).
Y2 = f (tmd−j, Vmp, tmd, dm4, dm3)
Is calculated. Further, in step S104, the deceleration speed Vd = Y1-Y2 is calculated.

In step S105, the speed Vd during deceleration calculated in step S104 is
It is determined whether or not Vd ≦ H <Vold is satisfied.

  If not satisfied (step S105: No), the process proceeds to step S106, the variable j is incremented (j = j + 1), and the process proceeds to step S108. If the condition is satisfied (step S105: Yes), the process proceeds to step S107, and the speed Vd at deceleration is set to H. This is a process for performing the remaining distance correction. Thereafter, the process proceeds to step S108.

In step S108, the current position command value X [i] is calculated by adding Vd to the previous position command value X [i-1] in the previous control cycle. That is,
X [i] = X [i-1] + Vd
And The deceleration stop control unit 15 outputs this to the servo amplifier 3.

In step S109, Vold is updated and the variable i is incremented. That is, the following is executed.
Vold = Vd, i = i + 1

  In step S110, it is confirmed whether j, which is a variable representing the elapsed time since the start of the deceleration operation, is equal to the deceleration time tmd. If they are not equal (step S110: No), step S103 and subsequent steps are executed again in the next control cycle. If j = tmd (step S110: Yes), the process ends. When the processing is finished, the movement amount is a desired (target) movement amount D, and the target speed v, acceleration time constant Ta, deceleration time constant Td, jerk time ratio specified in step S1 of FIG. An S-shaped position command as shown in FIG. 1 specified by 1 (rd1), jerk time ratio 2 (rd2), jerk time ratio 3 (rd3), and jerk time ratio 4 (rd4) The value is calculated. That is, the position command value in the deceleration stop process can be accurately calculated according to the designated shape.

  Next, the effect obtained when the command value is generated according to the present embodiment will be described. In the present embodiment, the central processing is equation (1) for calculating a position command value during acceleration.

  In the formula (1), the calculation formula corresponding to 1 ≦ i ≦ d1 is a formula for calculating the position at the jerk time 1 during the acceleration operation of the command value in FIG. A calculation formula corresponding to d1 <i ≦ ta−d2 is a formula for calculating the position of the command value in FIG. 1 at a constant acceleration time during the acceleration operation. Further, the calculation formula corresponding to ta−d2 <i ≦ ta corresponds to the formula for calculating the position at the jerk time 2 during the acceleration operation of the command value in FIG. By accurately calculating the position command value during acceleration operation and deceleration operation and the amount of movement necessary for deceleration by the equation (1), the command value having the shape as shown in FIG. 1 can be generated with high accuracy. it can.

  In the flowchart of FIG. 3, based on various information input in step S1, in step S3, acceleration time ta, jerk time 1 (d1), jerk time 2 (d2) during acceleration operation are calculated, Using these values, during the acceleration operation, the position command value candidate value Y at the elapsed time i (current control cycle) is calculated according to the equation (1) according to the elapsed time i (step S5). Further, if the elapsed time i passes the acceleration time ta, the operation becomes constant speed. Therefore, in step S6, v corresponding to the target speed is added to the position command value X [i-1] of the previous time (previous control cycle). Thus, a position command value for maintaining a constant speed is generated (step S6).

  In step S5 and step S6, while calculating the position command value candidate Y, if the candidate Y becomes the position command value in the current control cycle in the same control cycle, the movement necessary for decelerating and stopping Whether or not the amount is secured is checked in steps S8 and S9. Specifically, the predicted speed Vp when the position command value candidate Y becomes the position command value is calculated from the difference between Y and the previous position command value X [i−1], and the deceleration time td is calculated from this speed. The jerk time 3 (d3) and 4 (d4) are calculated (step S7), and the movement amount Dd required for deceleration is calculated using these information and the equation (1).

  Here, the reason why the movement amount necessary for deceleration can be calculated using the equation (1) is that the value calculated by substituting the acceleration time into the elapsed time in the equation (1) is the position command value in the acceleration time. Of course, this is because it can be regarded as a movement amount necessary for acceleration. Similarly, the value calculated by substituting the deceleration time for the elapsed time, the speed for starting deceleration to the target speed, the deceleration time for the acceleration time, and the jerk time for deceleration to the jerk time for acceleration is This can be regarded as the movement amount Dd required for deceleration.

  If the remaining distance R is larger than the movement amount Dd necessary for deceleration, it is determined that the movement amount necessary for deceleration can be secured even if the position command value candidate Y is used as the position command value of the current control cycle, Let Y be the position command value of the current control cycle (step S10). If the remaining distance R is smaller than the movement amount Dd required for deceleration, the position command value is calculated by performing deceleration stop processing instead of using the candidate Y as the position command value in the current control cycle. Is performed (step S12). If the timing to start the deceleration stop process is too early, the target movement amount will not be sufficient at the end of the deceleration stop process, and the correction amount to be corrected during the deceleration stop operation will be too large. If it is too much, the target movement amount is exceeded, but the deceleration stop process can be started at an appropriate timing by performing the deceleration stop process as in the present embodiment.

  The command values shown in FIG. 1 have the same pattern in which the shape of acceleration during deceleration is trapezoidal, even though there is a difference in acceleration time, deceleration time, and jerk time during acceleration and deceleration operations. Therefore, the position command value is generated using the equation (1) also at each time j = 1, 2,..., Tmd during the deceleration stop process shown in FIG.

  At this time, the parameter corresponding to the target speed v is Vmp, which is the speed at which deceleration starts, the deceleration time tmd is the parameter corresponding to the acceleration time, and the additional speed time 4 is the parameter corresponding to the additional speed time 1. (Dm4) is substituted for jerk time 3 (dm3) for the parameter corresponding to jerk time 2. Further, since the equation (1) calculates a command value for increasing the speed as the elapsed time i increases, in order to calculate a command value for performing the deceleration stop operation, tmd− obtained by subtracting the deceleration stop processing from the deceleration time. By applying j as the elapsed time, a command value whose speed decreases as j increases can be calculated.

At this time, the speed, which is the difference between the position command values during the deceleration stop process, is the difference between the position command value Y1 at the elapsed time tmd-j + 1 and the position command value Y2 at the elapsed time tmd-j, that is,
Y1 = f (tmd−j + 1, Vmp, tmd, dm4, dm3)
Y2 = f (tmd−j, Vmp, tmd, dm4, dm3)
Vd = Y1-Y2
(Steps S103 and S104). By adding this value Vd to the position command value X [i-1] in the previous control cycle, the position command value X [i] in the current control cycle is calculated (step S108).

In addition, when the speed calculated at each time j = 1, 2,..., Tmd during the deceleration operation is totaled to calculate the movement amount necessary for deceleration stop,
{F (tmd, Vmp, tmd, dm4, dm3) -f (tmd-1, Vmp, tmd, dm4, dm3)} +
{F (tmd-1, Vmp, tmd, dm4, dm3) -f (tmd-2, Vmp, tmd, dm4, dm3)} +
{F (tmd-2, Vmp, tmd, dm4, dm3) -f (tmd-3, Vmp, tmd, dm4, dm3)} +
...
{F (2, Vmp, tmd, dm4, dm3) −f (1, Vmp, tmd, dm4, dm3)} +
{F (1, Vmp, tmd, dm4, dm3) -f (0, Vmp, tmd, dm4, dm3)}
= F (tmd, Vmp, tmd, dm4, dm3)-f (0, Vmp, tmd, dm4, dm3)
= F (tmd, Vmp, tmd, dm4, dm3)
This coincides with the movement amount Dd required for deceleration calculated in step S8.

  This is because the stored predicted speed, deceleration time, jerk time 3 and jerk time 4 are determined as R> Dd in step S9 when the process proceeds to the deceleration stop operation (step S12). Is not the predicted speed Vp, deceleration time td, jerk speed time 3 (d3), 4 (d4) in the control cycle, but the predicted speed, deceleration time, jerk time 3, 4 of the previous control cycle These are the values stored as Vmp, tmd, dm3, and dm4 in step S11, respectively. Substituting these into equation (1) is equivalent to substituting into the above equation. Therefore, the amount of movement required for deceleration is calculated by equation (1), the amount of movement required for deceleration is compared with the remaining distance, the timing for starting the deceleration start operation is determined based on the comparison result, and further, By calculating the position command value using the same equation (1), it is possible to calculate the command value of the designated shape with high accuracy. This also has the effect that even if the processing required for command value generation is calculated not by floating point arithmetic but by integer arithmetic (fixed decimal point arithmetic), the amount of movement required for deceleration stop can be calculated without any deviation of one pulse. is there.

Basically, the deceleration stop process is controlled by calculating the speed with Vd = Y1−Y2 as described above and adding this to the position command value X [i−1] of the previous control cycle. A cycle position command value X [i] is calculated. The sum of the value of the position command value immediately before starting deceleration and the movement amount Dmd necessary for deceleration generally does not always match the desired movement amount D. Is calculated as the corrected remaining distance H (step S101), and the corrected remaining distance H is added to the position command value in some way during the deceleration stop process, and the position command value after the completion of the deceleration stop process is the desired movement. Correction corresponding to the amount D is performed. The specific method of correcting the corrected remaining distance described in the present embodiment is realized by inserting a speed corresponding to the corrected remaining distance as a speed during the deceleration stop process. Since the position command value at which the speed is gradually reduced is generated during the deceleration stop process, the corrected remaining distance H is Vd at time j ≦ Vd at time j with respect to a certain time j (= Vold)
In a control cycle in which is established (step S105: Yes), a process of setting the speed Vd to the corrected remaining distance H is performed (step S107). Even if the correction remaining distance H is reflected in the command value in this way for the Vd = Y1-Y2 series in which the speed gradually decreases in each control period of the deceleration time, the property of the speed gradually decreasing is not lost. There is an effect that the position command value at the time of deceleration stop can be generated with almost no change in the shape of the value.

When time i immediately before starting the deceleration stop process is set to i = k, the movement amount when the remaining correction distance is corrected and the deceleration stop process is completed is the position command value X [k] at time k and the deceleration stop. Is the sum of the travel distance Dmd and the corrected remaining distance H required for
X [k] + Dmd + H = X [k] + Dmd + (R−Dmd)
= X [k] + R
= X [k] + (D-X [k])
= D
Thus, the command value for positioning control can be generated without causing a shift in the desired movement amount after the deceleration stop is completed. Here, it is used that H = R−Dmd (step S101) and R = D−X [k] (step S11).

The method of correcting the corrected remaining distance H is not limited to this. For example, the corrected remaining distance H is divided into the number of deceleration times tmd so that the corrected remaining distance H is added up. The divided value may be added to the deceleration speed for each control time of the deceleration processing operation. A specific example of the division method is to calculate in proportion to the absolute value of the acceleration when the command value for the deceleration processing operation is calculated according to equation (1). Specifically, when v (j) is the speed when the elapsed time j has elapsed since the start of the deceleration stop process,
{| V (j−1) −v (j) | × H} / Vmp
Is added to the speed Vd at time j, and the position command value of the previous control cycle is added to calculate the position command value in the deceleration stop process.

  Note that if the amount of movement necessary for deceleration stop cannot be accurately calculated before the deceleration stop process is started, the corrected remaining distance H is also not accurately calculated. Even if the correction is performed based on the inaccurate correction remaining distance, there is a disadvantage that it does not coincide with the desired movement amount D at the end of the deceleration stop process. However, according to the present embodiment, the deceleration is performed according to the equation (1). When the position command value at the time of the stop operation is calculated, the amount of movement necessary for deceleration can be accurately calculated without any deviation of one pulse before starting deceleration, so that the above inconvenience does not occur. As a result, the command value can be generated with high accuracy so that the designated shape is obtained.

  In this embodiment, when determining the acceleration time and deceleration time, an acceleration time constant and a deceleration time constant are provided, and the acceleration time and deceleration time are determined from the speed, acceleration, and deceleration time constant. Alternatively, the acceleration at the time of deceleration may be designated and calculated from the relationship of acceleration time (or deceleration time) = speed / acceleration. In the present embodiment, the command value of the type in which the acceleration linearly increases or decreases in the jerk time has been described as an example, but the acceleration increases using a trigonometric function using the jerk time, Alternatively, it may be applied to a command value such as a decreasing type of universal cam curve. When applied to the universal cam curve, the expression (1) for calculating the position command value at the time of acceleration is merely an expression corresponding to the universal cam curve, and other processes may be exactly the same. In the present embodiment, the configuration using the rotary servo motor and the rotary encoder has been described for the positioning control. However, a linear scale may be used as the linear servo motor and the encoder. A stepping motor may be used instead of the servo motor.

Embodiment 2. FIG.
In the first embodiment, a positioning control command generating device that gives a target speed and generates a position command value for positioning control that sequentially performs acceleration operation, constant speed operation, and deceleration operation according to the target speed has been described. . In the same way, after receiving a speed change request signal during acceleration or constant speed, after receiving the speed change request signal, the speed during acceleration (or deceleration) operation to the changed speed is also in the specified shape, and the speed The command value can be generated by changing the target speed from the target speed to the change speed. This embodiment will explain the contents. FIG. 10 shows the configuration of positioning control command generating apparatus 1 in the present embodiment. In FIG. 10, a speed change position command calculation unit 16 is added to the configuration of FIG.

  FIG. 5 is a graph showing the speed and acceleration of the command value obtained by the present embodiment and the speed change request signal. The difference from the graph shown in FIG. 1 is that the vehicle accelerates at the target speed v immediately after the start of starting, and when the speed change request signal is received during the operation, the target speed is changed to the changed speed v2 and positioned at the desired movement amount D. This is a point for generating a command value for control. Here, when accelerating (or decelerating) from the target speed v to the change speed v2, acceleration is performed during the speed change acceleration time, and further, an additional speed time 5 until the acceleration reaches the peak acceleration during the speed change. In addition, the command value is generated so that the jerk time 6 from the peak acceleration until the acceleration becomes zero is required.

  FIG. 6 is a flowchart for explaining in detail the flow of processing in which the positioning control command generation device 1 according to the present embodiment generates a command value. Steps denoted by the same reference numerals as those in FIG. 3 are the same as those in FIG. 3 differs from FIG. 3 in step S20 for determining whether or not a speed change request has been received after the process of step S3, and in the case where a speed change request has been received (step S20: Yes), a position command for speed change. Step S21 for calculating the value candidate Y, and step S21 and subsequent steps are executed after executing step S21. If it is determined in step S20 that there is no speed change request (step S20: No), step S4 and subsequent steps are executed as in FIG.

  FIG. 7 is a flowchart for explaining the detailed contents of step S21 for calculating the position command value candidate Y at the time of speed change. In step S201, it is determined whether it is immediately after the speed change request. Immediately after the speed change request indicates that the control cycle is immediately after the speed change request signal is received (when the speed change request signal in FIG. 5 rises). If it is immediately after the speed change request (step S201: Yes), the process proceeds to step S202. If not (step S201: No), the process proceeds to step S206.

  In step S202, change speed v2, speed change acceleration time constant Tc, and speed change jerk time ratios 5 and 6 are obtained. Here, these values may be received immediately after the speed change request, or may be received in advance at the start of the command.

  In step S203, the position X0 and the speed v0 (current speed) immediately before receiving the speed change request are acquired as X0 = X [i-1] and v0 = X [i-1] -X [i-2]. To do.

  In step S204, the difference DV = v2-v0 between the current speed and the change speed is calculated, and the speed change request reception time i0 is stored.

In step S205, the speed change acceleration time tc and the speed change jerk time 5 and 6 d5 and d6 are calculated from the differential speed DV, the speed change acceleration / deceleration time constant Tc and the speed change jerk time ratio 5 and 6. calculate. In particular,
tc = (DV × Tc / Vr)
d5 = (rd5 × tc) / 100
d6 = (rd6 × tc) / 100
Calculate as

  In step S206, it is determined whether i-i0 is shorter than the speed change acceleration time tc. Here, i−i0 is a difference obtained by subtracting the speed change request reception time from the current time, and thus represents an elapsed time since the speed change request was received. In step S206, if i-i0 is smaller than the speed change acceleration time (tc) (step S206: Yes), the process proceeds to step S207. If i-i0 is larger (step S206: No), the process proceeds to step S208.

In step S207, the position command value candidate value Y is calculated by the speed change position command calculation unit 16 according to the following equation (2) using the position X0, the velocity v0 calculated in step S203, and the equation (1). To do. Note that the calculation of equation (1) is executed by the position command calculator 11 as described above.
Y = X0 + v0 * (i−i0) + f (i−i0, DV, tc, d5, d6) (2)

In step S208, the position command value candidate value Y is added to the position X [i-1] in the previous control cycle by the change speed v2, that is,
Y = X [i-1] + v2
Calculate according to When the process of step S207 or S208 is completed, step S21 in FIG. 6 is completed, and thereafter, step S7 and subsequent steps are executed. In step S7 and subsequent steps, the same processing as in the first embodiment is performed, and thus the description thereof is omitted.

  Next, effects obtained in this embodiment will be described. The point of calculating a position command value for positioning control is the same as in the first embodiment. The difference from the first embodiment is that the position command value candidate Y is calculated in accordance with the presence / absence of a speed change request signal. The position X0 and the speed v0 in the control cycle immediately before receiving the speed change request signal are calculated (step S203), and the difference speed DV between the change speed and the speed when the speed change request signal is received is calculated (step S204). The speed change acceleration time tc and the speed change additional speed times 5 and 6 d5 and d6, which are information necessary for the acceleration operation at the time of speed change, are calculated from the speed DV (step S205). If the difference between the current time i and the speed change request reception time i0 is equal to or less than the speed change acceleration time tc, the position command value for the acceleration operation at the time of speed change is calculated by equation (2) (step S207). If it is equal to or greater than tc, the position command value candidate Y is calculated by adding the change speed v2 to the position command value X [i-1] of the previous control cycle, assuming that the change speed has been reached.

  The meaning of the formula (2) will be described with reference to FIG. 8 showing a speed waveform and a speed change request at the time of speed change. In FIG. 8, the black circles represent the speed at each time (the connection of the black circles is represented as the speed). The expression (2) is composed of three terms, and X0 in the first term is from the start of the command to the time immediately before receiving the speed change request signal (from time 1 to time i0− in FIG. 8). 1) represents the amount of movement. The second term v0 * (i-i0) is the speed at time i0-1 (equal to the target speed v in FIG. 8) immediately before the speed change request signal is received, and the time when the speed change request is received. The amount of movement after i0 is also indicated. The third term f (i-i0, DV, tc, d5, d6) is the speed DV from the stop state immediately after receiving the speed change request signal (DV = v2-v in FIG. 8). Corresponds to a position command value at time i-i0 when moving according to a pattern with acceleration time tc and jerk time d5 and d6, respectively.

  Note that the third term is equal to the movement amount represented by the area of the portion surrounded by the broken line of speed = v, the time interval [i0, i], and the thick speed curve in FIG. A position command value candidate Y obtained by summing all of the first, second, and third terms is a portion surrounded by a speed curve, a time axis, and a broken line of time i shown in FIG. Represents the amount of movement represented by the area. Therefore, there is an effect that it is possible to easily calculate the command value for changing the speed by using the equation (1). Further, since the process after step S7 such as the determination of the timing for starting the deceleration stop process and the deceleration stop process is performed in the same manner as in the first embodiment, the amount of movement required for the deceleration stop can be reduced by one pulse. It is possible to calculate accurately, thereby calculating command values with high accuracy and small calculation load for the shape specified by acceleration time constant, deceleration time constant, jerk time 1, 2, 3, 4 There is an effect that it becomes possible to do. Therefore, even if the speed changing process is performed, the command value can be accurately calculated according to the designated shape.

  In FIGS. 6 and 8, the change speed v2 is described as an example in which the change speed v2 is larger than the target speed v, but may be smaller than the target speed. Further, the speed change process is performed while the command value maintains a constant speed. However, the speed change process may be performed during the acceleration operation, which can be realized by performing the calculation according to the flowchart of FIG. it can.

  Furthermore, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the above embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. In the case where a certain effect can be obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention. Furthermore, the constituent elements over different embodiments may be appropriately combined.

  As described above, the positioning control command generation device according to the present invention is useful when generating a command value that serves as a target reference signal during positioning control when positioning control of a mechanical load using a motor such as a servo motor. In particular, it is suitable for a positioning control command generation device that generates a command value with high accuracy so as to have a specified shape.

DESCRIPTION OF SYMBOLS 1 Position control command generator 2 Position command value 3 Servo amplifier 4 Current 5 Servo motor 6 Encoder 7 Position 8 Mechanical load 11 Position command calculation part 12 Acceleration position command calculation part 13 Stop movement amount calculation part 14 Deceleration start timing judgment part 15 Deceleration stop control unit 16 Speed change position command calculation unit

Claims (8)

A position command calculator for calculating a position command value based on the elapsed time, speed, acceleration time, and jerk time;
At the time of acceleration operation, the position command calculation unit is configured such that the elapsed time is the elapsed time for each predetermined period from the start of the position command, the speed is the target speed, and the jerk speed time is the jerk time during the acceleration operation. An acceleration position command calculation unit that outputs a position command value calculated by
Stop movement that outputs the position command value calculated by the position command calculation unit as a movement amount necessary for deceleration stop, using the elapsed time and the acceleration time as the deceleration time, and the jerk time as the jerk time during deceleration. A quantity calculator;
A deceleration start timing determination unit that determines whether to start a deceleration stop operation by comparing a remaining distance that is a difference between a target movement amount and the position command value and a movement amount necessary for the deceleration stop; ,
When the deceleration start timing determination unit determines to start the deceleration stop operation, the corrected remaining distance is calculated based on the difference between the remaining distance and the amount of movement necessary for deceleration calculated in the control cycle immediately before starting the deceleration stop. After that, using the calculation result of the position command calculation unit, the position command value of the deceleration stop operation is calculated and output , and further, at the timing when the corrected remaining distance falls below the speed at the time of deceleration, A deceleration stop control unit that calculates a value obtained by adding a position command value before the previous control cycle to the corrected remaining distance as a current position command value ;
A positioning control command generating device comprising: A position command calculator for calculating a position command value based on the elapsed time, speed, acceleration time, and jerk time;
At the time of acceleration operation, the position command calculation unit is configured such that the elapsed time is the elapsed time for each predetermined period from the start of the position command, the speed is the target speed, and the jerk speed time is the jerk time during the acceleration operation. An acceleration position command calculation unit that outputs a position command value calculated by
Stop movement that outputs the position command value calculated by the position command calculation unit as a movement amount necessary for deceleration stop, using the elapsed time and the acceleration time as the deceleration time, and the jerk time as the jerk time during deceleration. A quantity calculator;
A deceleration start timing determination unit that determines whether to start a deceleration stop operation by comparing a remaining distance that is a difference between a target movement amount and the position command value and a movement amount necessary for the deceleration stop; ,
When the deceleration start timing determination unit determines to start the deceleration stop operation, the corrected remaining distance is calculated based on the difference between the remaining distance and the amount of movement necessary for deceleration calculated in the control cycle immediately before starting the deceleration stop. After that, using the calculation result of the position command calculation unit, the position command value of the deceleration stop operation is calculated and output, and the corrected remaining distance is summed to the corrected remaining distance. Deceleration that calculates the current position command value by dividing it into the number of deceleration times in cycle units and adding the divided value, the speed of each control cycle during deceleration operation, and the position command value before the previous control cycle A stop control unit;
With
A positioning control command generation device characterized by the above. The deceleration stop control unit divides the correction remaining distance so as to be a value proportional to the absolute value of the acceleration in the deceleration operation to obtain the divided value.
The positioning control command generating device according to claim 2. The deceleration stop control unit calculates the position command by setting the elapsed time as a time obtained by subtracting the predetermined time from the deceleration time, the acceleration time as the deceleration time, and the jerk time as the jerk time during deceleration. parts by using the difference between the position command value calculated, positioning control command generating device according to any one of claims 1 to 3, characterized in that calculates and outputs the position command value of the deceleration stop operation . A position value immediately before reception of the speed change request, a value obtained by multiplying a current speed value immediately before the reception by a difference time between the current time and the reception time, and the time as the difference time and the speed The difference between the change speed and the current speed, the acceleration time as the speed change acceleration time, the jerk time as the speed change jerk time, the total value of the position command values calculated by the position command calculation unit, A speed change position command calculation unit for calculating a position command value after the reception;
The positioning control command generation device according to any one of claims 1 to 4 , further comprising: The stop movement amount calculation unit is configured to determine the position as the current predicted speed obtained from the difference between the current position command value calculated by the position command calculation unit during acceleration operation and the position command value before the predetermined period. The position control command generation device according to any one of claims 1 to 5, wherein the position command value calculated by the command calculation unit is output as a movement amount necessary for deceleration stop. The deceleration stop control unit
The elapsed time is the time obtained by adding the predetermined period to the time obtained by subtracting the elapsed time in units of the predetermined period from the start of deceleration from the deceleration time, the acceleration time is the deceleration time, and the jerk speed time is The time obtained by subtracting the elapsed time in the unit of the predetermined period from the start of deceleration from the deceleration time from the first position command value calculated by the position command calculation unit as the jerk time during deceleration The deceleration time obtained by subtracting the second position command value calculated by the position command calculation unit using the acceleration time as the deceleration time and the jerk time as the jerk time during deceleration. The position control command generation device according to any one of claims 1 to 6, wherein a value obtained by adding a position command value before a cycle is calculated as a current position command value. The position command calculator calculates the elapsed time as i, the speed as v, the acceleration time as t _a , the jerk time from the acceleration 0 to the peak acceleration as d ₁ , and the peak acceleration as 0. calculates the following f when placing the jerk time to reach d _2, and the value indicated by _{(i, v, t a,} d 1, d 2) as the position command value

Positioning control command generating device according to any one of claims 1 7, characterized in.

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