Modeling and optimization of head-collision of a flexible joint robot

In order to ensure the safety of human, robots are designed with flexible features, such as tunable stiffness robot joint and link. However, the collision between the robot with flexible joints and human is not clearly. In this paper, we focus on the collision, in which the characteristics of inertia and flexibility of the robot are comprehensively considered, between flexible joints robot and human. First, we propose an equivalent collision model between flexible joint robot and human head. And the calculation methods of the effective mass and effective stiffness of the flexible robot are given. Second, the calculation method of the maximum collision force between the flexible joint robot and human head is obtained through a large number of simulation data. The validity of the formula for calculating the maximum collision force is proved by simulations of various configurations and collision directions. Finally, the calculation formula of the maximum collision force is used to determine the minimum collision direction under a certain manipulator configuration and optimize the minimum collision configuration when the manipulator end position and the collision direction are given. The minimum collision direction or the minimum collision configuration can be used in the planning of the robot to reduce injury to human.