关键词: 机械臂, 碰撞检测, 改进外力观测器, 动态阈值, 安全机制

Abstract: Aiming at the safety in the process of human-me cooperation,an external force observer based on improved generalized momentum was proposed to detect external forces.The simplified flexible manipulator model under external force was established,and the force analysis was carried out to identify the equivalent joint force of robot when the collision occurred.A second-order feedforward external force observer was designed to detect external forces,and the dynamic threshold was set according to the observed value of the observer.When the observed value exceeded the limited range of dynamic threshold,the control system confirmed that the collision had occured.To ensure that the operator and robot safety,the touch-stop mode would be switched immediately to achieve the safety of the reaction at different speeds.The validity and feasibility of the external force observer and the dynamic threshold with Universal Robot 5(UR5)lightweight manipulator experimental platform was verified.

Key words: manipulator, impact detection, improved external force observer, dynamic threshold, safety mechanism