CN111433703A - Rotation control device, moving body, and transfer robot - Google Patents

Abstract

The invention provides a rotation control device, a moving body and a transfer robot, which can restrain the deformation of the posture and the movement even if the control of a rotating body is disturbed. The rotation control device includes: a 1 st controller that controls a rotational speed of the 1 st rotating body to a 1 st target rotational speed; and a 2 nd controller that controls a rotation speed of the 2 nd rotating body to a 2 nd rotation speed of the target, the rotation control device selectively executing: a 1 st control mode in which the 1 st controller acquires a 1 st measurement value of a rotation state of the 1 st rotating body and a 2 nd measurement value of a rotation state of the 2 nd rotating body, calculates correction control for bringing a relative relationship between the 1 st measurement value and the 2 nd measurement value close to a target relative relationship, and applies the correction control to the 1 st rotating body; and a 2 nd control mode in which the 2 nd controller acquires a 1 st measurement value of the rotation state of the 1 st rotating body and a 2 nd measurement value of the rotation state of the 2 nd rotating body, and applies the correction control to the 2 nd rotating body.

Description

Rotation control device, moving body and handling robot

technical field

The present invention relates to a rotation control device, a moving body, and a transfer robot for controlling the rotation state of a rotating body.

Background technique

Conventionally, for example, a moving body such as a transfer robot, a multi-joint robot, etc. are provided with a plurality of rotating bodies such as wheels and joints, and control is performed by driving each rotating body with each motor and individually controlling the rotational state of each rotating body. Postures and actions of moving bodies and robots.

For example, Patent Document 1 discloses a technique of performing phase difference synchronization (PLL) control on a reference signal indicating a rotational reference of a motor and a rotational angle detected by the motor.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2002-78374

SUMMARY OF THE INVENTION

The problem to be solved by the invention

However, even when the respective rotational states of the plurality of rotating bodies are synchronized with the reference signal, if disturbances occur in the control of the rotating bodies due to signal delay, noise, etc., the mutual synchronization of the rotating bodies may still occur. Disorder, the posture and movement of the moving body will still be deformed.

Therefore, an object of the present invention is to provide a rotation control device, a moving body, and a transfer robot that can suppress deformation of posture and motion even when disturbance occurs in the control of the rotating body.

methods for solving problems

A rotation control device according to one aspect of the present invention includes: a first controller that controls the rotation speed of the first rotating body to a target first rotation speed; and a second controller that controls the rotation speed of the second rotating body The rotation control device selectively executes the first control mode, in which the first controller acquires the first measured value of the rotation state of the first rotation body and the rotation state of the second rotation body to achieve the target second rotation speed. the second measured value of the The second controller acquires the first measured value of the rotation state of the first rotating body and the second measured value of the rotating state of the second rotating body, and applies the correction control to the second rotating body.

A moving body according to one aspect of the present invention includes: a base; a first wheel that moves the base; a second wheel that moves the base; a first driver that rotationally drives the first wheel; and rotationally drives the second wheel the second driver; a first controller that controls the rotation speed of the first rotating body, which is one of the first wheel and the first driver, to a target first rotation speed; and a second controller that controls The moving body selectively executes the first control mode, in which the rotational speed of the second rotating body is controlled to a target second rotational speed as one of the second wheel and the second actuator, and the first controller obtains the The first measured value of the rotating state of the first rotating body and the second measured value of the rotating state of the second rotating body are calculated to make the relative relationship between the first measured value and the second measured value close to the target relative relationship. control and apply the correction control to the first rotating body; in a second control mode, the second controller obtains a first measured value of the rotation state of the first rotating body and a first measurement value of the rotating state of the second rotating body 2 measured values, and apply the above-mentioned correction control to the above-mentioned second rotating body.

A transfer robot according to one aspect of the present invention includes: a base having a mounting table on which a conveyed object is placed; a first wheel for moving the base; a second wheel for moving the base; and a first wheel for rotationally driving the first wheel a driver; a second driver for rotationally driving the second wheel; a first controller for controlling the rotation speed of the first rotating body, which is one of the first wheel and the first driver, to a target first rotation speed and a second controller that controls the rotational speed of the second rotating body as one of the second wheel and the second driver to a target second rotational speed, and the transfer robot selectively executes: the first control mode, the first controller obtains the first measured value of the rotation state of the first rotating body and the second measured value of the rotating state of the second rotating body, and calculates the difference between the first measured value and the second measured value. In the second control mode, the second controller obtains the first measured value of the rotation state in the first rotating body and the The second measured value of the rotation state in the second rotating body is applied to the second rotating body, and the correction control is applied to the second rotating body.

effect of invention

According to the present invention, even when the control of the rotating body is disturbed, since one of the first rotating body and the second rotating body rotates following the other, the mounting of the first rotating body and the second rotating body can be suppressed. Deformation in the posture and motion of the moving body of the rotating body and the robot.

Description of drawings

FIG. 1 is a perspective view showing an embodiment of a transfer robot according to the present invention.

2 is a block diagram including a control system of the transfer robot according to the embodiment of the present invention.

FIG. 3 is a diagram showing an operation sequence of an external computer and two motor units.

FIG. 4 is a diagram showing an example of a format of a control command.

FIG. 5 is a diagram showing an example of the rotational speed of the wheel motor in the second motor unit.

FIG. 6 is a diagram showing an example of a format of a measurement command.

FIG. 7 is a diagram showing an example of the format of the status report of the second motor unit.

FIG. 8 is a diagram showing follow-up control executed by the first main control unit.

FIG. 9 is a diagram showing an example of the rotational speed of the wheel motor in the first motor unit.

FIG. 10 is a diagram showing following control in a turning operation.

FIG. 11 is a diagram showing a first other example of the following control.

FIG. 12 is a diagram showing a second other example of the follow-up control.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<Transportation robot>

FIG. 1 is a perspective view showing an embodiment of a transfer robot according to the present invention.

The transfer robot 1 of the present embodiment also corresponds to one embodiment of the moving body of the present invention. This transfer robot 1 is used for, for example, transfer of materials in a factory, or the like.

The transfer robot 1 includes a vehicle body (base) 2 and two wheels 4A and 4B that are supported and rotated by the vehicle body 2 . The vehicle body 2 is a substantially horizontal frame provided on the lower part of the transfer robot 1 . The wheels 4A and 4B have the same shape and size, and are arranged concentrically.

The vehicle body 2 is mounted with two wheel motors 6A, 6B that drive the wheels 4A, 4B, respectively. In addition, the vehicle body 2 is mounted with a battery case 8 that accommodates a battery that is a power source for driving the wheel motors 6A and 6B. Furthermore, printed circuit boards 10A, 10B, 12A, and 12B for driving the wheel motors 6A and 6B are mounted on the vehicle body 2 . Here, the printed boards 10A and 10B include a drive circuit including an inverter and a motor driver, and the printed boards 12A and 12B include a main control circuit including a microcomputer board.

1 shows the case where the printed circuit boards 10A, 10B, 12A, and 12B are mounted on the shelves, but the printed circuit boards 10A, 10B, 12A, and 12B themselves may be used as shelves.

In addition, a plurality of pillars 14 are attached to the vehicle body 2 , and the pillars 14 support the stage 16 .

<Control system>

FIG. 2 is a block diagram including a control system of the transfer robot 1 according to the embodiment of the present invention. The transfer robot 1 can communicate with an external computer (external control device) 40 that remotely operates the transfer robot 1 through wireless communication. The method of wireless communication includes, but is not limited to, Wi-Fi (registered trademark).

The transfer robot 1 has two motor units, that is, a first motor unit 42A and a second motor unit 42B. The two motor units 42A, 42B correspond to the two wheels 4A, 4B shown in FIG. 1 in a one-to-one correspondence, and the two motor units 42A, 42B include wheel motors 6A, 6B that drive the corresponding wheels 4A, 4B, respectively. In the following description, when distinguishing each element corresponding to each of the first motor unit 42A and the second motor unit 42B, the expressions "first" and "second" are used in some cases.

Electric power is supplied to the motor units 42A and 42B by the power supply 43 . The power source 43 is a battery housed in the battery case 8 (see FIG. 1 ).

In the present embodiment, the two motor units 42A and 42B have the same configuration as each other as hardware, and include wheel motors 6A and 6B, wireless communication circuits 44A and 44B, main control units 46A and 46B, memories 48A and 48B, and motors, respectively. Drive control units 50A, 50B, drive circuits 52A, 52B, and speed sensors 54A, 54B.

The wireless communication circuit 44A, the main control unit 46A, the memory 48A, the motor drive control unit 50A, and the drive circuit 52A of the first motor unit 42A are each mounted on two printed boards as hardware, and mounted on the four printed boards 10A shown in FIG. 1 . , 10B, 12A, 12B of the two printed circuit boards 10A, 12A located on the side of the first wheel 4A. Specifically, the wireless communication circuit 44A, the main control unit 46A, the memory 48A, and the motor drive control unit 50A are mounted on the lower printed circuit board 12A, and the drive circuit 52A is mounted on the upper printed circuit board 10A.

The wireless communication circuit 44B, the main control unit 46B, the memory 48B, the motor drive control unit 50B, and the drive circuit 52B of the second motor unit 42B are similarly mounted as hardware on two printed boards, respectively, and mounted on the four printed circuit boards shown in FIG. 1 . Among the substrates 10A, 10B, 12A, and 12B, the two printed circuit boards 10B and 12B are located on the side of the second wheel 4B. Specifically, the wireless communication circuit 44B, the main control unit 46B, the memory 48B, and the motor drive control unit 50B are mounted on the lower printed circuit board 12B, and the drive circuit 52B is mounted on the upper printed circuit board 10B.

Both of the two wireless communication circuits 44A and 44B have a function of wirelessly communicating with the external computer 40 . In the present embodiment, the first wireless communication circuit 44A is usually used for wireless communication with the external computer 40, and the second wireless communication circuit 44B is used when a communication failure occurs due to, for example, a failure of the first wireless communication circuit 44A. backup. In addition, the second wireless communication circuit 44B can also be used as an auxiliary of the first wireless communication circuit 44A. For example, the first wireless communication circuit 44A may be used for reception from the external computer 40 , and the second wireless communication circuit 44B may be used for transmission to the external computer 40 .

In the present embodiment, each of the main control units 46A and 46B is, for example, a processor, and each reads and executes a program stored in a recording medium (not shown), whereby the combination of the two main control units 46A and 46B is the main control unit 46A and 46B. One embodiment of the inventive rotation control device operates. Therefore, in the present embodiment, the program (program code) itself read from the recording medium realizes the functions of the main control units 46A and 46B. In addition, the recording medium on which the program is recorded can constitute an embodiment of the present invention.

The first main control unit 46A performs wireless communication with the external computer 40 using the wireless communication circuit 44A. In addition, the first main control unit 46A controls the drive of the wheel motor 6A by controlling the motor drive control unit 50A. And the 1st main control part 46A and the 2nd main control part 46B are wired so that communication is possible.

The second main control unit 46B also controls the drive of the wheel motor 6B by controlling the motor drive control unit 50B. In addition, when communication failure occurs in the first main control unit 46A, the second main control unit 46B performs wireless communication with the external computer 40 using the wireless communication circuit 44B instead of the first main control unit 46A.

The memories 48A and 48B respectively store data necessary for the respective processing of the main control units 46A and 46B. The main control units 46A and 46B respectively read required data from the memories 48A and 48B. The memories 48A and 48B in this embodiment are volatile memories (eg, SRAM), but may be nonvolatile memories (eg, flash memory). In addition, each of the memories 48A and 48B may include both a volatile memory and a nonvolatile memory.

The motor drive control units 50A, 50B control the drive (eg, rotational speed) of the wheel motors 6A, 6B in accordance with commands from the main control units 46A, 46B. Each of the motor drive control units 50A and 50B can perform, for example, PID (Proportional-Integral-Differential) control and vector control, and is, for example, a microprocessor, an ASIC (Application Specific Integrated Circuit), or a DSP (Digital Signal). Processor; digital signal processor).

The drive circuits 52A and 52B drive the wheel motors 6A and 6B under the control of the motor drive control units 50A and 50B, respectively.

The speed sensors 54A and 54B output electric signals indicating the rotational speeds of the wheel motors 6A and 6B, respectively. Each of the speed sensors 54A and 54B is, for example, a Hall sensor mounted inside the wheel motor 6A or 6B, and converts a magnetic field into an electric signal. The motor drive control units 50A and 50B calculate the rotational speeds of the wheel motors 6A and 6B based on the output signals of the speed sensors 54A and 54B, respectively. That is, the motor drive control units 50A and 50B measure the rotational speeds of the corresponding wheel motors 6A and 6B, respectively. The measured values of the rotational speeds of the wheel motors 6A and 6B are notified to the main control units 46A and 46B, and the main control units 46A and 46B use the values of the rotational speeds of the wheel motors 6A and 6B for the wheel motors 6A and 46B. The command for controlling the drive of 6B is given to the motor drive control units 50A and 50B.

In addition, the motor drive control units 50A and 50B can calculate the torques of the wheel motors 6A and 6B using a known calculation method based on the current values of the drive circuits 52A and 52B, respectively. That is, the drive circuits 52A and 52B can measure the torques of the wheel motors 6A and 6B. The measured torque values of the wheel motors 6A and 6B are notified to the main control units 46A and 46B, and the main control units 46A and 46B can use the torque values of the wheel motors 6A and 6B for the wheel motor 6A. A command for controlling the drive of 6B is given to the motor drive control units 50A and 50B.

<Operation example of motor control>

An example in which the motor units 42A and 42B control the control operations of the wheel motors 6A and 6B based on a control command from the external computer 40 will be described.

FIG. 3 is a diagram showing an operation sequence of the external computer 40 and the two motor units 42A and 42B. In addition, the operations of the motor units 42A and 42B are represented by dividing into communication threads 61A and 61B and control threads 62A and 62B.

In order to make the transfer robot 1 draw a predetermined trajectory, the external computer 40 calculates the target speed of each of the two wheel motors 6A and 6B included in the transfer robot 1, and transmits a control command indicating the target speed to the transfer robot 1 through wireless communication. . In the transfer robot 1, a control command is usually received by the first motor unit 42A.

FIG. 4 is a diagram showing an example of a format of a control command.

As shown in FIG. 4 , an example of the format of the control command includes a field indicating a command type, a field indicating a target achievement time (Duration; duration), a field indicating a first device ID (device ID of the first motor unit 42A), a field indicating A field representing the target speed of the first wheel motor 6A, a field representing the second device ID (device ID of the second motor unit 42B), and a field representing the target speed of the second wheel motor 6B.

The field indicating the command type contains a bit string indicating that the command sent is a control command to set the target speed. The field indicating the target achievement time includes a bit string indicating the time until the wheel motors 6A and 6B reach the target speed after receiving the control command. The field representing the device ID contains a bit string representing the ID of the motor unit having the wheel motor to be controlled by the control command. That is, each of the two fields representing the device ID includes a bit string representing the device ID of the first motor unit 42A or a bit string representing the device ID of the second motor unit 42B. The field representing the target speed following the field representing the device ID of the first motor unit 42A includes a bit string representing the target speed of the first wheel motor 6A. The field representing the target speed following the field representing the device ID of the second motor unit 42B includes a bit string representing the target speed of the second wheel motor 6B.

In this control command, for example, it is assumed that the target achievement time is designated as 100 ms, the target speed of the first wheel motor 6A is designated as 100 rpm, and the target speed of the second wheel motor 6B is designated as 200 rpm. In this case, the control command means that the first motor unit 42A should control the rotation speed of the wheel motor 6A to 100 rpm, and the second motor unit 42B should control the rotation speed of the wheel motor 6B within 100 ms after receiving the control command. The speed is controlled to 200rpm.

Returning to FIG. 3 , when the wireless communication circuit 44A receives a control command in the first motor unit 42A, the main control unit 46A compares the target speeds of the two wheel motors 6A and 6B, and determines that the operation of the transfer robot 1 is a straight-forward operation. Still turning. That is, when the two target velocities are equal, it is determined to be a straight running motion, and when the two target speeds are different, it is determined to be a turning motion.

In addition, a control command instructing the target speed of the second wheel motor 6B is transmitted from the first motor unit 42A to the second motor unit 42B through wired communication. The format of the control command is obtained by deleting the device ID and target speed for the first motor unit 42A from the format shown in FIG. 4 .

<Acceleration Control>

The motor units 42A and 42B to which the target speed is instructed by the control command respectively create a control plan for reaching the target speed within the target achievement time. That is, the main control units 46A and 46B specify the instantaneous target speeds of the wheel motors 6A and 6B at each instant until the target achievement time. The instants referred to here are the instants at intervals of a fixed control cycle. In addition, the instantaneous target speed is determined by interpolation, for example, based on the current rotational speed of each motor, the target speed of the motor specified in the control command, and the target achievement time specified in the control command.

Specifically, when both of the two wheel motors 6A and 6B are stopped (when the rotation speed is 0 rpm) at the time of receiving the control command of the above-mentioned hypothetical example, the first main control unit 46A causes, for example, the first wheel motor 6A to stop. The instantaneous target speed at each moment of every 1ms is determined in such a way that the rotational speed of 1rpm increases every 1ms. Moreover, the 2nd main control part 46B determines the instantaneous target speed at each moment of every 1 ms so that the rotational speed of the 2nd wheel motor 6B may increase by 2 rpm every 1 ms, for example. Thus, after 100 ms has elapsed, the rotational speed of the first wheel motor 6A reaches 100 rpm, and the rotational speed of the second wheel motor 6B reaches 200 rpm. In this example, the main control units 46A and 46B determine the instantaneous target speed by, for example, linear interpolation, but other interpolation algorithms may be used.

As described above, the main control units 46A and 46B that determine the instantaneous target speeds of the wheel motors 6A and 6B store the instantaneous target speeds of the wheel motors 6A and 6B in the memories 48A and 48B.

After that, the main control units 46A and 46B control the motor drive control units 50A and 50B according to the control plan to perform acceleration control on the rotational speeds of the wheel motors 6A and 6B. That is, the main control units 46A, 46B read the instantaneous target speeds of the wheel motors 6A, 6B from the memories 48A, 48B at each instant, and repeatedly control the motor drive control units 50A, 50B at a fixed control cycle so that the wheel motors 6A, 6B The rotational speed of 6B becomes the instantaneous target speed. In the above example, the control period of each motor is 1 ms, but the control period is not limited to 1 ms, and may be 5 ms, for example.

<Constant speed control>

When the wheel motors 6A and 6B reach the target speed by the above-described acceleration control, the main control unit 46B executes constant speed control for maintaining the rotational speed of the wheel motor 6B of the second motor unit 42B at the target speed.

FIG. 5 is a diagram showing an example of the rotational speed of the wheel motor 6B in the second motor unit 42B. The horizontal axis of FIG. 5 represents the elapsed time, and the vertical axis represents the rotational speed of the wheel motor 6B.

The second wheel motor 6B achieves the target speed during the target achievement time (Duration; duration) by the acceleration control. Thereafter, the constant speed control is performed to maintain the rotational speed of the second wheel motor 6B at the target speed.

However, for example, when disturbances such as noise occur, the control in the motor unit 42B may be disturbed, and the rotational speed of the wheel motor 6B may deviate from the target speed. In addition, in the present embodiment, since the second motor unit 42B receives the control command from the first motor unit 42A through wired communication, disturbance of control due to communication delay of the control command can be suppressed by utilizing the robustness of wired communication. When the motor unit 42B receives a control command from the external computer 40 in parallel with the first motor unit 42A through wireless communication, a communication delay or the like may also cause the above-mentioned disturbance.

<Follow Control>

In the present embodiment, as shown in FIG. 3 , the first motor unit 42A executes following so that the transfer robot 1 can draw a predetermined trajectory even when such a disturbance occurs in the second motor unit 42B. control.

When the following control is started, the first main control unit 46A transmits a measurement command requesting motor information to the second main control unit 46B through wired communication.

FIG. 6 is a diagram showing an example of a format of a measurement command.

As shown in FIG. 6 , an example of the format of the measurement command includes a field indicating a command type, a field indicating a state measurement start time, a field indicating a reporting duration, and a field indicating a reporting period (measurement period). The field indicating the command type contains a bit string indicating that the transmitted command is a measurement command.

In the second motor unit 42B, the main control unit 46B that has received the measurement command stores the measurement command in the memory 48B. In addition, the main control unit 46B executes the state measurement at the timing of the start of the state measurement designated by the measurement command. Specifically, the main control unit 46B causes the motor drive control unit 50B to measure the rotational speed and torque of the second wheel motor 6B, and acquires the measured values of the rotational speed and torque from the motor drive control unit 50B. After the measurement is completed, the main control unit 46B transmits a status report indicating the measurement result to the first motor unit 42A as motor information of the second motor unit 42B through wired communication.

FIG. 7 is a diagram showing an example of the format of the status report of the second motor unit 42B.

As shown in FIG. 7 , an example of the format of the status report has a field indicating a report type, a field indicating a speed, and a field indicating a torque. The field of the report type includes a bit string indicating that the report is a status report of the second motor unit 42B. The speed field contains a bit string representing the measured value of the speed. The field of torque contains a bit string representing the measured value of torque.

When receiving the status report from the second motor unit 42B, the main control unit 46A of the first motor unit 42A executes the following for the rotation state of the first wheel motor 6A to follow the rotation state of the second wheel motor 6B indicated by the status report. control (described later).

After that, the main control unit 46B of the second motor unit 42B executes the state measurement at the report cycle (measurement cycle) designated by the measurement command, and transmits the state report of the second motor unit 42B to the first motor unit 42A through wired communication. Such measurement and reporting are repeated until the reporting duration specified by the measurement command elapses. When the report duration period elapses, the second motor unit 42B ends the state measurement and the transmission of the state report. In addition, there is a case where an indefinite period of time is designated as the reporting duration, and in this case, measurement and reporting are repeated until a measurement stop command is received.

FIG. 8 is a diagram showing the follow-up control executed by the first main control unit 46A.

In the example shown in FIG. 8 , the follow-up control is executed using the speed measurement value included in the status report transmitted from the second motor unit 42B and the speed measurement value among the torque measurement values. In addition, when it is determined in the above-described speed determination that it is a straight-forward motion, the following control shown in FIG. 8 is executed.

In the follow-up control, the first main control unit 46A causes the motor drive control unit 50B to measure the speed of the first wheel motor 6A, and obtains the measured value θ of the rotational speed of the second wheel motor 6B from the second motor unit 42B. ₂ is divided by the measured value θ ₁ of the rotational speed obtained by the measurement. As a result, the difference in rotational speed between the two wheel motors 6A and 6B is calculated.

The first main control unit 46A calculates the proportional operation 71 and the integral operation 72 in the PI control based on the rotational speed difference. This PI control is correction control for correcting the rotational speed of the first wheel motor 6A so that the rotational speed difference is brought close to zero. The first main control unit 46A calculates the corrected target speed by adding the component of the correction control to the target speed given to the first wheel motor 6A by the control command. Then, the first main control unit 46A controls the motor drive control unit 50A so that the first wheel motor 6A becomes the corrected target speed.

FIG. 9 is a diagram showing an example of the rotational speed of the wheel motor 6A in the first motor unit 42A. The horizontal axis of FIG. 9 represents the elapsed time, and the vertical axis represents the rotational speed of the wheel motor. In addition, in FIG. 9, the example of the rotational speed of the electric motor 6A for 1st wheels is shown by the solid line, and the example of the rotational speed of the electric motor 6B for 2nd wheels is shown by the broken line.

The rotational speed of the first wheel motor 6A reaches the target speed during the target achievement time (Duration; duration) by the same acceleration control as the second wheel motor 6B. After that, by performing the following control shown in FIG. 8 , the rotational speed of the first wheel motor 6A follows the rotational speed of the second wheel motor 6B. That is, the rotational speed of the first wheel motor 6A is the same as that of the second wheel motor 6A, regardless of whether the rotation speed of the second wheel motor 6B is maintained at the target speed or when the above-mentioned disturbance occurs. The rotational speed of the electric motor 6B is the same rotational speed. As a result, even when interference occurs in the second motor unit 42B, the transfer robot 1 maintains the straight travel operation.

However, disturbance due to noise or the like may also occur in the first motor unit 42A. Therefore, in the present embodiment, a threshold value is set for the target speed, and the first main control unit 46A compares the threshold value with the rotational speed to detect the occurrence of disturbance. That is, when the measured value of the rotational speed in the first wheel motor 6A deviates from the target speed and exceeds the threshold value, it is considered that a disturbance has occurred in the first motor unit 42A. However, when the measured value of the rotational speed of the second wheel motor 6B exceeds the threshold value first, the rotational speed of the first wheel motor 6A exceeds the threshold value due to the follow-up control, so it is not considered that the first motor A disturbance has occurred in cell 42A.

As shown in FIG. 3 , in phase 1 from the end of the acceleration control to the detection of the occurrence of disturbance in the first motor unit 42A, the constant speed control is executed in the second motor unit 42B, and the following is executed in the first motor unit 42A control. Then, in Phase 2 after the occurrence of disturbance in the first motor unit 42A is detected, the constant velocity control is executed in the first motor unit 42A, and the follow-up control is executed in the second motor unit 42B. That is, the operation is alternately controlled in the first motor unit 42A and the second motor unit 42B. During the alternation of such control operations, a control command requesting to stop reporting motor information is transmitted from the first motor unit 42A to the second motor unit 42B, and a control command requesting to start the follow-up control is also transmitted. After these control commands are sent, the first motor unit 42A performs constant speed control and periodically reports motor information to the second motor unit 42B. Then, the second motor unit 42B that has received the control command executes follow-up control in which the rotational speed of the second wheel motor 6B follows the rotational speed of the first wheel motor 6A.

In the constant velocity control process of the phase 2, when the rotational speed of the first wheel motor 6A returns to within the threshold range, it is considered that the disturbance in the first motor unit 42A ends. Then, in phase 3 after the end of the disturbance, the first motor unit 42A and the second motor unit 42B alternately control operations again, the second motor unit 42B performs constant velocity control, and the first motor unit 42A performs Follow control.

In this way, as shown in FIG. 9 , the first motor unit 42A and the second motor unit 42B are alternately controlled to operate according to the occurrence and termination of the detection disturbance, and when a disturbance occurs in either of the motor units 42A and 42B ( That is, in any stage), the rotational speeds of the second wheel motor 6B and the first wheel motor 6A follow each other, and the straight running operation is maintained.

<Following control during turning action>

Next, the following control in the turning operation will be described. The above-mentioned alternation of the control operations is also performed during the turning operation, but for convenience of description, the following description will be given by taking the case of performing the following control in the first motor unit 42A as an example.

FIG. 10 is a diagram showing following control in a turning operation.

During the turning operation, the rotational speed of the first wheel motor 6A and the rotational speed of the second wheel motor 6B are maintained at a ratio corresponding to a predetermined turning radius. That is, when it is determined that the turning operation is performed in the above-mentioned speed determination, the ratio γ of the target speed is obtained, and the rotational speed of the first wheel motor 6A is controlled so as to maintain the ratio γ in the follow-up control.

Specifically, the first main control unit 46A causes the motor drive control unit 50B to measure the speed of the first wheel motor 6A. In addition, the first main control unit 46A multiplies the measured value θ ₂ of the rotational speed of the second wheel motor 6B obtained from the second motor unit 42B by a ratio γ of the target speed, and divides the multiplication result by the first wheel motor The measured value θ ₁ of the speed of the electric motor 6A.

As a result, the rotational speed of the first wheel motor 6A and the measured rotational speed of the first wheel motor 6A are obtained in which the ratio of the rotational speeds of the two wheel motors 6A and 6B is maintained at the target speed ratio γ. poor.

The first main control unit 46A calculates the proportional operation 71 and the integral operation 72 in the PI control based on the difference. This PI control is correction control for correcting the rotational speed of the first wheel motor 6A so that the difference is close to zero and the ratio of the rotational speeds of the two wheel motors 6A and 6B is close to the ratio γ. The first main control unit 46A calculates the corrected target speed by adding the component of the correction control to the target speed given to the first wheel motor 6A by the control command. Then, the first main control unit 46A controls the motor drive control unit 50A so that the first wheel motor 6A becomes the corrected target speed.

As a result of such follow-up control, the ratio of the rotational speeds of the two wheel motors 6A and 6B is maintained at the ratio γ of the target speed, and the transfer robot 1 maintains a predetermined turning operation even when interference occurs.

<Another example of following control>

Next, another follow-up control that can be executed instead of the above-described follow-up control will be described. However, the following control during the straight-running motion will be described, and the description of the following control during the turning motion will be omitted. In addition, the case where the follow-up control is performed in the first motor unit 42A will be described as an example.

FIG. 11 is a diagram showing another first example of the following control.

PID control is used in the follow-up control shown in FIG. 11 instead of the PI control used in the follow-up control shown in FIG. 8 . That is, the first main control unit 46A calculates the proportional operation 71 and the integral operation in the PID control based on the rotational speed difference between the two wheel motors 6A and 6B calculated in the same manner as the following control shown in FIG. 8 . 72 and differential action 73. Similar to the PI control, this PID control is also correction control for correcting the rotational speed of the first wheel motor 6A so that the rotational speed difference is close to zero. A quick correction is also achieved in this case. In addition, both PI control and PID control achieve high-precision control with simple logic. Therefore, high-speed and high-precision control can be realized by using PI control and PID control.

The first main control unit 46A adds the component of the correction control to the target speed given to the first wheel motor 6A by the control command, and controls the motor drive control so that the first wheel motor 6A becomes the corrected target speed Section 50A.

FIG. 12 is a diagram showing another second example of the follow-up control.

As shown in FIG. 12 , in the second example of the following control, the measured value θ ₂ of the rotational speed of the second wheel motor 6B obtained from the second motor unit 42B is used instead of the target speed given by the control command. That is, the first main control unit 46A calculates the corrected target speed by adding the components of the correction control based on the PI control to the rotational speed indicated by the measured value θ ₂ . Then, the first main control unit 46A controls the motor drive control unit 50A so that the first wheel motor 6A becomes the corrected target speed.

According to such follow-up control, for example, even when a continuous control deviation or the like occurs between the first motor unit 42A and the second motor unit 42B, the rotational speed of the first wheel motor 6A follows the second wheel motor. Rotation speed of 6B.

In addition, although the conveyance system provided with one conveyance robot was exemplified in the above description, the present invention may be applied to, for example, a conveyance system in which one pallet or the like is conveyed by a plurality of conveyance robots.

In addition, in the above description, as the rotating body whose rotational speed is controlled by the rotation control device, the wheel and the motor for moving the moving body are exemplified. The rotational speed of a series of conveying rollers, etc., of the sheets together.

In addition, although the above description shows an example in which the relative relationship of the rotational speed is maintained in the follow-up control, in the present invention, the relative relationship of the torque may be maintained instead of the rotational speed, or the relative relationship of the rotational angle may be maintained. .

Description of reference numerals

1...mobile body (automatic device), 2...vehicle body (support body), 6A, 6B...wheel motor, 40...external computer (external control device), 42A...first motor unit, 42B...second motor unit , 44A...wireless communication circuit, 46A, 46B...main control unit, 50A, 50B...motor drive control unit, 52A, 52B...drive circuit.

Claims (9)

1. a rotation control device, is characterized in that, has: a first controller that controls the rotational speed of the first rotating body to a target first rotational speed; and a second controller that controls the rotational speed of the second rotating body to a target second rotational speed, The rotation control device selectively executes a first control mode in which the first controller acquires a first measurement value of the rotation state of the first rotating body and a second measurement of the rotation state of the second rotating body value, the correction control for making the relative relationship between the first measurement value and the second measurement value approach the target relative relationship is calculated, and the correction control is applied to the first rotating body; in the second control mode, the the second controller acquires the first measured value of the rotation state of the first rotating body and the second measured value of the rotating state of the second rotating body, and applies the correction control to the second rotating body . 2. The rotation control device according to claim 1, wherein When the rotational speed of the first rotating body deviates from the first rotational speed by more than a predetermined degree, the second control mode is selected, The first control mode is selected when the rotational speed of the first rotating body approaches within a predetermined level with respect to the first rotational speed. 3. The rotation control device according to claim 1 or 2, characterized in that, At least one of the first controller and the second controller determines the relative relationship of the target based on the first rotational speed and the second rotational speed given from the outside. 4. The rotation control device according to any one of claims 1 to 3, characterized in that, In the first control mode, the first controller uses, as the target rotational speed of the first rotating body, a rotational speed obtained from a second measured value of a rotational state in the second rotating body, Instead of the 1st rotational speed, In the second control mode, the second controller uses, as the target rotational speed of the second rotating body, a rotational speed obtained from a first measured value of a rotational state in the first rotating body, instead of the second rotational speed. 5. The rotation control device according to any one of claims 1 to 4, characterized in that, The first controller and the second controller use at least one of PI control and PID control as the correction control. 6. The rotation control device according to any one of claims 1 to 5, characterized in that, At least one of the first controller and the second controller acquires the first rotational speed and the second rotational speed from the outside via wireless communication, The rotation speed used by the other party among the first rotation speed and the second rotation speed is given to the other party with respect to the one through wired communication. 7. The rotation control device according to claim 6, wherein Both the first controller and the second controller have a function of wirelessly communicating with the outside, The tasks of acquiring the first rotational speed and the second rotational speed from the outside are switched between the first controller and the second controller according to a communication state. 8. A moving body, characterized in that it has: pedestal; a first wheel for moving the base; a second wheel for moving said base; a first driver for rotationally driving the first wheel; a second drive for rotationally driving the second wheel; a first controller that controls the rotational speed of the first rotating body, which is one of the first wheel and the first actuator, to a target first rotational speed; and a second controller that controls the rotational speed of the second rotating body, which is one of the second wheel and the second actuator, to a target second rotational speed, The movable body selectively executes a first control mode in which the first controller acquires a first measured value of the rotational state of the first rotating body and a second measured value of the rotational state of the second rotating body , calculates the correction control for making the relative relationship between the first measurement value and the second measurement value approach the target relative relationship, and applies the correction control to the first rotating body; in the second control mode, the The second controller acquires the first measured value of the rotation state of the first rotating body and the second measured value of the rotating state of the second rotating body, and applies the correction control to the second rotating body. 9. A handling robot, characterized in that, has: A base having a mounting table on which the objects to be carried are placed; a first wheel for moving the base; a second wheel for moving said base; a first driver for rotationally driving the first wheel; a second drive for rotationally driving the second wheel; a first controller that controls the rotational speed of the first rotating body, which is one of the first wheel and the first actuator, to a target first rotational speed; and a second controller that controls the rotational speed of the second rotating body, which is one of the second wheel and the second actuator, to a target second rotational speed, The transfer robot selectively executes a first control mode in which the first controller acquires a first measured value of the rotational state of the first rotating body and a second measured value of the rotational state of the second rotating body , calculates the correction control for making the relative relationship between the first measurement value and the second measurement value approach the target relative relationship, and applies the correction control to the first rotating body; in the second control mode, the The second controller acquires the first measurement value of the rotation state in the first rotary body and the second measurement value of the rotation state in the second rotary body, and applies the correction control to the second rotation body.

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