A manipulator's safety control strategy based on fast continuous collision detection

Abstract

In this paper we propose a strictly conservative and novel hybrid safety control strategy consisting of the pre-contact safety strategy and the post-contact safety strategy in order to provide safety guarantees and enable continuous motions. An optimal motion trajectory planning that limits jerk, acceleration and velocity of robot motion and can obtain a time optimal motion is introduced as post-contact safety strategy. The optimal motion trajectory planning can reduce the impact forces during occurring collision and keep high efficiency of manipulator and continuous motions. Then we describe a fast continuous collision detection as pre-contact safety strategy to avoid collision. The advantages of this method are that it can solve the tunneling problem and check the whole trajectory. Finally, the proposed hybrid safety control strategy has been implemented on a 7 degrees-of-freedom(DOF) humanoid manipulator, and the experimental results demonstrate the validity of the novel hybrid safety control strategy.