Robot control system, lower-level control apparatus, and control method for robot

A lower-level control apparatus forming a robot control system with a robot and an upper-level control apparatus, the lower-level control apparatus configured to execute:

• (a) processing of transmitting a control command to a servo control unit of the robot and receiving robot status information representing a status of the robot from the servo control unit with respect to a preset control period;
• (b) processing of transmitting the robot status information to the upper-level control apparatus in synchronization with the control period;
• and
• (c) processing of receiving command information from the upper-level control apparatus and creating a next control command from the command information, wherein
• in the processing (c),
• when failed to receive the command information from the upper-level control apparatus until a time-out time before a time to transmit the next control command to the servo control unit, creating the next control command using a previous control command without using the command information and transmitting the command to the servo control unit.

A control method for a robot in a robot control system including the robot having a servo control unit, a lower-level control apparatus, and an upper-level control apparatus, comprising:

• (a) transmitting a control command to the servo control unit and receiving robot status information representing a status of the robot from the servo control unit with respect to a preset control period by the lower-level control apparatus;
• and
• (b) transmitting command information for creation of the control command to the lower-level control apparatus by the upper-level control apparatus, wherein
• at (a), the lower-level control apparatus transmits the robot status information to the upper-level control apparatus in synchronization with the control period, and
• at (b), the upper-level control apparatus transmits the command information to the lower-level control apparatus within a predetermined transmission time shorter than the control period from a time when receiving the robot status information from the lower-level control apparatus.