Safe and Fluent Industrial Human Robot Collaboration Via Combination of PFL, SSM and Escape Trajectories

In industrial collaborative robotics, safety, fluency as well as productivity are among the most important requirements to implement effective applications. In this work, a generalized formulation that combines the Power and Force Limiting and the Speed and Separation Monitoring criteria is firstly developed; then, a novel method that combines it with the possibility of executing an escape trajectory with the aim to enhance the levels of fluency and performance while guaranteeing human safety is presented. In particular, starting from a reference trajectory assigned to the manipulator to execute a specific task, a suitable joint acceleration is searched by formulating the problem as a Quadratic Programming problem under linearized kinematic and safety constraints. The method is then tested and experimentally validated. Results show, through fluency metrics, the effectiveness of the developed method with respect to the Power and Force Limiting criterion, the Speed and Separation Monitoring criterion as well as their combination.