A Force Controlled Finishing Robot System with a Task-Directed Robot Language

Abstract

We have developed a force controlled robot system for finishing tasks such as grinding, chamfering, and polishing tasks in machining plants. Casted workpieces for finishing differ in size, shape, or both. Thus, a position controlled robot system cannot handle these workpieces. Force controlled robot systems can handle them because they can follow the edges or the surfaces of the workpieces using the force control function. Until now, however, the force controlled robot systems have been difficult to use for the following two reasons. One is that many force control. parameters-for example, a force control direction, a force detecting direction, a desired force pattern, and force control gains-have to be assigned in order to make the system work. The other is that you should be very careful to teach the robot to conduct a finishing task which needs contact between the robot and the workpiece. To cope with these issues, we have developed a task-directed robot language and also a controller with force controlled guide function. The robot language enables the force control parameters to be assigned with only three key parameters-a task name, a tool code, and a tool center point-, and one motion command. The force controlled guide function allows you to guide the robot easily in work environments without fear of collision. The experiment of chamfering the edges of a part in an injection molding machine is also reported.