Structure of robot control system

• US 6,091,219 A
• Filed: 10/08/1998
• Issued: 07/18/2000
• Est. Priority Date: 10/08/1997
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Yatsuya, Noritaka, Maruo, Satoshi, Inagaki, Takamitsu, Kawamura, Yoshio, Kojima, Masatoshi, Ogawa, Akira
• Primary Examiner(s): Sircus, Brian
• Application Number:
  US09/168,348
• Time in Patent Office: 649 Days
• Field of Search: 318/625, 318/562, 318/568, 318/567, 318/569, 318/563
• US Class Current: 318/562
• CPC Class Codes: G05B 19/31 for continuous-path control
• CPC Class Codes: G05B 2219/33236 Add check data to message to check faulty communication
• CPC Class Codes: G05B 2219/37149 Multiplexer to send encoder and rotor pole position to same output lines
• CPC Class Codes: G05B 2219/42284 Stop and brake motor
• CPC Class Codes: G05B 2219/42291 Regenerate faulty feedback by last measurement after detection excess error

Abstract

A robot control system is provided which controls a plurality of servomotors for moving a hand and articulated arms of a robot. The robot control system includes a plurality of position detectors, a motor control driver, and a serial communication path. The position detectors detect rotational positions of the servomotors and output the rotational positions in the form of serial data, respectively. The serial communication path is disposed between the motor control driver and the position detectors to transmit request signals provided by the motor control driver to the position detectors to request the position detectors to output the rotational positions.

Claims

1. A robot control apparatus comprising:

a plurality of servomotors which move preselected components of a robot, respectively;

a plurality of position detectors which detect rotational positions of said servomotors and output the rotational positions in the form of serial data, respectively;

a motor control driver which controls said servomotors based on the rotational positions detected by said position detectors and required positions, wherein said motor control driver detects an error in transmission between each of said position detectors and said motor control driver by checking a format of the serial data outputted from each of said position detectors, an error check code contained in the serial data, and a time required for the transmission between each of said position detectors and said motor control driver; and

a serial communication path disposed between said motor control driver and said position detectors to transmit request signals provided by said motor control driver to said position detectors to request said position detectors to output the rotational positions, said position detectors being connected to said serial communication path in parallel to each other, respectively; and

a storage circuit which stores therein the rotational positions detected by said position detectors in a cycle and a position estimating circuit which estimates the rotational positions of said servomotors based on the rotational positions derived in previous cycles when transmission between said position detectors and said motor control driver is in error in this cycle, and wherein said motor control driver controls said servomotors based on the estimated rotational positions.

2. A robot control apparatus as set forth in claim 1, wherein the motor control driver stops the servomotors when an error in transmission between the position detectors and the motor control driver continues to occur a preselected number of times.

3. A robot control apparatus comprising:

a plurality of servomotors which move preselected components of a robot, respectively, each servomotor including a motor casing having formed thereon a spigot and an annular sealing member installed in the spigot, the robot having a motor mount which has formed therein a socket into which the spigot of the motor casing is fitted through the annular sealing member with a portion of the motor mount around the socket connecting directly with a portion of the motor casing around the spigot for grounding the motor casing through the robot;

a plurality of position detectors which detect rotational positions of said servomotors and output the rotational positions in the form of serial data, respectively;

a motor control driver which controls said servomotors based on the rotational positions detected by said position detectors and required positions; and

a serial communication path, connecting said motor control driver and said position detectors, to transmit request signals provided by said motor control driver to said position detectors to request said position detectors to output the rotational positions, said position detectors being connected to said serial communication path in parallel to each other, respectively.