Hybrid Control of a Manipulator and its Application

In complex asks such as sewing or assembly, where a robot has a mechanical interaction with its environments, we cannot expect to get a good result only by using the conventional positioning control of the robot. This is because that even the smallest positioning error may cause a large reaction force between the robot and its object, then it will stop the motion required for the task or, the worst case, it will damage the object as well as the robot itself. From this point of view, various kinds of control methods which enable a robot to move compliantly to avoid producing an excessive force when there is an interaction between the robot and objects In this paper we will propose a hybrid control method which can control both position and force of the manipulator in the given task-oriented coordinates. We can expect to have a good task quality by using this method compared with the conventional positioning control. The experiments of some actual tasks using an articulated manipulator with 2 d.o.f. will be also shown to demonstrate the feasibility and applicability of the proposed method.