Operating Unknown Constrained Mechanisms Based on Motion Prediction and Impedance Control

In order to meet the needs for assistive robot manipulators in operating various constrained mechanisms,a control method based on motion prediction and impedance control is proposed.A rolling manipulation strategy of exploration-prediction -adjustment is employed,through impedance control to provide compliant interaction between the assistive manipulator and unknown constrained mechanisms.Firstly,the motion capability of the constrained mechanism is explored to build its motion model according to the passed motion trajectory of the manipulator.Then,motion direction of the mechanism is predicted based on the motion model.Finally,the trajectory of manipulator is adjusted in alignment with the predicted direction, while the magnitude of the velocity is dynamically adjusted according to the interaction force.Based on this continuous rolling adjustment,safety and efficiency of a manipulator for operating unknown constrained mechanisms are enhanced.Experiments of autonomous door opening utilizing a 6DoF assistive manipulator with a six-dimensional force/torque sensor demonstrate the validity of the proposed method.