Patent ID: 8280552
Filing Date: 2012-10-02
Classification: B25J,G05B

Abstract:
1. A power assist system comprising an operation part operated by an operator; an operation force detection device that detects operation force applied on the operation part; a robot arm that supports the operation part; a drive mechanism that drives the robot arm; an external force measurement device that measures force applied when the robot arm is brought into contact with an environment, or an external force estimation device that estimates force applied when the supporting part is brought into contact with the environment; and a speed detection device that detects movement speed of the operation part, or a speed estimation device that estimates the movement speed of the operation part, wherein a control device is provided that obtains a corrected external force based on the external force obtained by the external force measurement device or the external force estimation device and a component along the external force of the operation force detected by the operation force detection device, controls the drive mechanism so as to maintain the state that the operation force and the corrected external force act on the operation part and the component along the external force of the operation force and the corrected external force acting on the robot arm are always balanced with each other, compares the component along the external force of the operation force detected by the operation force detection device with the external force obtained by the external force measurement device or the external force estimation device, regards the speed of the operation part calculated from the external force as speed of the operation part along the external force calculated from the component along the external force of the operation force so as to obtain the corrected external force when the component along the external force of the operation force is opposite to the external force and the external force is larger than the component along the external force of the operation force, and adopts the external force without any operation as the corrected external force when the component along the external force of the operation force has the same direction as the external force or the external force is smaller than the component along the external force of the operation force.