Compliant human-robot object transfer based on modular 3-axis force sensor for collaborative manufacturing

The primary motivation of this paper is to present a compliant and cost-effective solution for object transfer between human and robot. The application prospect of this study is robot-human collaboration in manufacturing. To achieve above goals, a novel modular 3-axis force sensor is proposed for the grasping system to achieve interactive force sensing. Compliant object transfer control strategy, which is composed of incremental force control mode and gravity balance control mode, is proposed for object transfer between human and robot. A prototype of underactuated grasping system which is mounted on the proposed modular 3-axis force sensor is fabricated to investigate the effectiveness of the proposed interactive control strategy. Experimental results reveal that the incremental force control mode is suitable for the lighter objects with a higher interactive sensitivity. For transferring heavier objects, the gravity balance control mode is more suitable. In gravity balance control mode, the human hand could achieve a quasi-static equilibrium with the object, and achieve a compliant transfer operation. Due to the above characteristic, the proposed control strategy has the potentials to enhance the object transfer compliance and safety in the human-robot object transfer process.