JPH0538689A - Dispersive control system of multi-joint robot - Google Patents

Abstract

PURPOSE:To provide possibility of performing fine and/or complicated works by connecting together external bus controllers of a main controller through an external bus, and connecting a common memory with this external bus. CONSTITUTION:A dispersive control system concerned comprises a main controller 2 including external bus controllers 8, 14, a plurality of local controllers 3 mounted at robot joints a-e, and an external bus 15 to connect the external bus controllers 8, 14 with each other. As plurality of driver units 12-1, 12-2 for driving actuator, etc., are connected with these local controllers 3, and with them are also connected sensor units 13-1, 13-2 which process signals from each external field sensor mounted at the periphery of the robot joint, and a common memory 4 is connected with the external bus 15. Thereby a multi- joint robot is dispersively controlled robot joint by robot joint to enable performing fine works and/or complicated works. Thus control with ample flexibility is achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system most suitable for controlling inspection / work robots used in various plants, and in particular, by controlling a multi-joint robot in a distributed manner for each robot joint. The present invention relates to a distributed control system for an articulated robot that achieves reliability, redundancy, maintainability, and reduction in size and weight of mounted equipment.

[0002]

2. Description of the Related Art In a nuclear power plant and other various plants where it is dangerous for personnel to enter, it is common practice to have a robot remotely inspect and work. In particular, for relatively simple work and nighttime monitoring, there is a tendency for the robot to inspect and work autonomously without the assistance of personnel.

In such an inspection / work robot, since the work place and work contents are complicated and not uniform, the teaching / working robots usually used for industrial assembling robots
Playback control technology cannot be adopted. In order for the inspection / work robot to perform delicate work or complicated work, a multi-joint robot having a plurality of joints is required. Therefore, many research institutions are currently conducting research and development on articulated robots.

Here, a method of collectively controlling a multi-joint robot having a plurality of joints driven by an actuator by one multi-task using one large computer provided on the ground side has been considered. In the case of the control method, the posture of the robot can be calculated at high speed, but communication control, driver unit control, etc. become considerably complicated, and a huge amount of software is required.

In particular, when working in a plant where the working environment is complicated, the robot can be operated while constantly monitoring the surrounding state using an external sensor such as a proximity sensor, a contact sensor, or a force sensor so as not to collide with surrounding structures. This tendency becomes stronger because it is necessary to perform drive control.

Therefore, in order to drive and control an articulated robot with one computer, control speed, reliability, maintenance, etc. become problems. In addition, it becomes difficult to respond to changes in robot joint specifications and control modes.

Even in a system having a plurality of computers on the ground side, the same problem as described above occurs.

On the other hand, it has been considered that a computer, a driver unit, a sensor unit and the like are provided for each joint of the articulated robot to control the articulated robot in a distributed manner. In this case, since the control functions can be distributed, the system becomes very simple, which is preferable in terms of control speed, reliability, and maintenance measures.

[0009]

However, when distributed control of a multi-joint robot is carried out for each robot joint in this way, how to communicate between computers, how to divide functions, computers and drivers for each robot joint. The current situation was how to mount the unit etc.

In view of the above, the present invention makes it possible to decentralize control of the articulated robot for each robot joint so that delicate work or complicated work can be performed, and thus the articulated robot has high speed and flexibility. The purpose of the present invention is to provide a distributed control system.

[0011]

In order to achieve the above object, a distributed control system for an articulated robot according to the present invention controls a robot having a plurality of joints driven by actuators by distributing it to each robot joint. In a distributed control system for a robot, a main controller having an external bus controller and a plurality of local controllers attached to each robot joint, an external bus connecting each external bus controller to each other, and each of these local controllers are provided. A plurality of driver units that are connected to drive the actuators, a sensor unit that is connected to each of the local controllers and processes a signal from an external sensor attached around the robot joint, and the external bus Shared memory It includes those were.

[0012]

According to the present invention configured as described above, for example, the attitude control calculation is performed by the main controller, the calculated robot joint angles are written in the shared memory, and the result written in the shared memory by each local controller. The posture of the robot is controlled by obtaining the target posture angle of the robot and controlling the driver unit. Also, by detecting the signal of the external sensor installed in each robot joint with each local controller, writing the detection result to the above shared memory, and reading the result written in this shared memory with the main controller, the whole robot can be read. Understand the posture and the state of the outside world. Further, depending on the usage state, only the external sensor process is executed by the main controller, the attitude control calculation is performed by one of the local controllers, and the driver unit connected to another local controller by one of the local controllers, The control method can be easily changed by controlling the sensor unit.

[0013]

An embodiment of the present invention will now be described with reference to the drawings.

FIG. 1 is a block diagram showing a main part of an embodiment of a distributed control system for a robot according to the present invention.
FIG. 2 is a block diagram showing a detailed configuration of one local controller in FIG. 1.

In FIG. 1, reference numeral 1 is a robot body of an articulated robot to be controlled.
Is driven by an actuator, for example, a total of five robot joints, that is, a grip portion a, a first joint b, and a second joint.
The joint c, the third joint d, and the fourth joint e are provided.

On the other hand, the control system for controlling the robot main body 1 of the multi-joint robot includes a main controller 2 and a total of five local controllers 3 provided in each of the robot joints a to e (here, in FIG. Part a
Local controller 3 and fourth joint e installed in
(Only the local controller 3 installed in the robot is illustrated and the local controllers 3 installed in the other robot joints b to d are omitted) and the shared memory 4.

The main controller 2 is mainly composed of an MPU (multi-process unit) 5, a main memory 6, a man-machine interface 7 and an external bus controller 8, which are interconnected via an internal bus 9. The communication control between them is performed.

Further, each local controller 3 has an MP
U10, main memory 11, two driver units 12-1, 12-2 for driving the manipulator, two sensor units 13-1, 13-2 and external bus controller 14
It is mainly composed of and. Driver unit 12-1,
12-2 and two sensor units 13-1 and 13-2 are provided because robot joints a to e having two degrees of freedom are used. Increases or decreases according to the number of degrees of freedom.

The main controller 2 and the local controllers 3, 3 ... Are connected to each other via the external bus 15 by the external bus controllers 8 and 14, 14 ... Also, with each local controller 3,
Driver units 12-1, 12-2 and sensor unit 1
An internal bus 16 connects between 3-1 and 13-2.

The driver units 12-1 and 12-2 respectively include a motor 17 and an encoder 1 as shown in FIG.
8, a brake 19 (may not be attached depending on use conditions), and a limit switch 20 are connected.
The driver units 12-1 and 12-2 each include a motor control circuit 21 and an EFT bridge circuit 22.

The sensor units 13-1 and 13-2 are shown in FIG.
, The contact sensor 23 and the proximity sensor 2 respectively.
4 and the external sensor of the force sensor 25 are connected. The external sensors 23 to 25 are attached around the robot joints a to e, respectively.
3-1 and 13-2 process signals from the external sensors 23 to 25.

FIGS. 3 and 4 show an example of a local controller 3 which is optimal for mounting on a robot joint having two degrees of freedom.

The local controller 3 includes an external bus control board 26 (one) and a control board 27 (1) in which the MPU 10 and the main memory 11 are combined.
, And driver boards 28, 29 (2 sheets) consisting of the motor control circuit 21 and the FET bridge circuit 22.
And sensor boards 30 and 31 for processing signals from external sensors mounted on the outer skin of the robot.
It consists of 6 boards (2). The external bus control board 26 and the control board 27 are connected with a connector 32, and the other boards are connected with an internal bus cable 34 via a connector 33. The external bus control of the two local controllers 3 and 3 is performed. An external bus cable 35 is connected between the boards 26, 26 via a connector 35.

As described above, by constructing the local controller 3 as a unit by function, the driver boards 28, 29 and the sensor boards 30, 31 can be added and changed very easily. In addition, by using semiconductor technology, the driver boards 30 and 31 are incorporated into the motor, thereby facilitating the attachment of the local controller 3 to the robot joint.

Next, the operation of the above embodiment will be described.

When a request is input to the main controller 2 via the man-machine interface 7, the main controller 2 performs work planning, attitude calculation, and general control for each local controller 3, 3.

Here, the local controllers 3, 3 ...
To the external bus controllers 8 and 14, 14 ...
This is performed by writing command data to the shared memory 4 provided in the external bus 15 via the. The address of the shared memory 4 is set to an address uniquely determined by any of the controllers 2 and 3, 3.

Each of these external bus controllers 8 and 1
4, 14 ... Are composed of bus aviators and bus drivers. This bus arbiter determines which of the MPUs 5 and 10, 10 ... Gives priority to the bus use request, and normally manages the external bus 15.

The shared memory 4 has the robot joints a to e.
The memory address is designated for each of the local controllers 3, 3 ... Corresponding to, and command data and state data are written at the designated locations.

Each local controller 3 reads the command data at the location corresponding to its own address written in the shared memory 4 and controls the driver units 12-1, 12-2 and the sensor units 13-1, 13-2. I do. Also,
Each local controller 3 has a driver unit 12-
Control state of 1, 12-2, sensor units 13-1, 13-2
Write the detection data from the shared memory 4 to its own address via the external bus controller 14.

The respective driver units 12-1, 12-2 and sensor unit 13-of the robot joints a, b ...
Addresses uniquely determined by any of the controllers 2 and 3, 3 ... Are set in 1 and 13-2 as in the shared memory 4. With this address, the driver units 12-1 and 12-2 can be controlled by the MPU 8 of the local controller 3 of the robot joint and controlled by the MPU 8.8 of the main controller 2 and the other local controllers 3, 3. ..

Local controller 3 in the robot joint
When controlling the driver units 12-1 and 12-2, command data and status data are transmitted and received via the internal bus 16 without using the external bus 15.

The external bus controller 14 switches the control between the local controller 3 in the robot joint and the MPU 11 of the main controller 2 and the MPUs 8, 8 ... Of the other local controllers 3, 3. In the external bus controller 14, the other controllers 2 and 3, 3 ...
When the command is output to, the control of the local controller 3 in the robot joint is temporarily stopped during that period. The same applies to the control of the sensor units 13-1 and 13-2.

By writing a control mode change command in the shared memory 4, the control mode can be switched. Further, since this control system has a configuration in which any driver unit 12-1, 12-2 and sensor unit 13-1, 13-2 can be accessed from any of the controllers 2 and 3, 3 ... Can be used

Therefore, the control load can be organically balanced by distributing the functions depending on the use and the working state. For example, the main controller 2 may control the attitude of the robot body 1 and the local controllers 3, 3 ... At the same time may perform force control.
It can be easily realized by setting the logic of giving priority to the command of the main controller 2 when the external force is not applied to the robot joint portion and giving priority to the local controllers 3, 3 ... When the external force is applied.

Further, even when the MPU 10 of a certain robot joint is in an abnormal state, the other local controller 3 controls its driver units 12-1, 12-2 and sensor units 13-1, 13-2. You can also choose to do so.

[0037]

Since the present invention has the above-mentioned structure,
Data transfer between the main controller and each local controller is performed by using the external bus and shared memory, so the speed is significantly higher than that of commonly used serial transfer and high reliability is obtained. be able to.

Further, it is possible to switch to an arbitrary control method depending on the application. In particular, since the control posture and the force control can be combined in delicate work and complicated work, it is possible to easily avoid collision with surrounding obstacles and avoid breakage of the work target. Also,
Since the functions can be distributed between the main controller and each local controller, software creation and maintenance is very easy.

Further, the local controller can be constructed by unitizing it by function, and by such a configuration, the mounting can be facilitated and the expandability can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of an embodiment of a distributed control system for an articulated robot according to the present invention.

FIG. 2 is a block diagram showing details of local control in FIG.

FIG. 3 is a front view showing an example of a local controller attached to a robot joint having two degrees of freedom.

FIG. 4 is a perspective view of the local controller shown in FIG.

[Explanation of symbols]

 1 Robot main body 2 Main controller 3 Local controller 4 Shared memory 8,14 External bus controller 9,16 External bus 12-1, 12-2 Driver unit 13-1, 13-2 Sensor unit 15 External bus

Claims (1)

[Claims] 1. A decentralized control system for a multi-joint robot, wherein a multi-joint robot having a plurality of robot joints driven by actuators is distributed and controlled for each robot joint. A plurality of local controllers attached to the robot joints, an external bus connecting the external bus controllers to each other, a plurality of driver units connected to the local controllers to drive the actuators, and the local buses. Distributing a multi-joint robot, comprising: a sensor unit that is connected to a controller and that processes a signal from an external sensor attached around the robot joint; and a shared memory that is connected to the external bus. Control system.