High-speed reverse control of a soft manipulator using an electrorheological clutch

Recently, humans and robots have started working together in the field of medical treatment and welfare. In such a work environment, it is required that robots operate in a safe manner that avoids collisions or inadvertent contact with their human colleagues. A three degree-of-freedom (3-DOF) soft manipulator with an electrorheological (ER) clutch and a pneumatic cushion sensor has been developed as a robot arm that meets this demand. The buffer method employed in this manipulator reduces the force of a collision by making its joint flexible when a collision occurs. In this study, the power of such an impact is further reduced by developing a method for high-speed reverse control in the event of a collision. However, this method imposes a load on the electric motor when the arm is working under inertia. This problem is solved by dispersing the energy of the arm by using the friction of an ER clutch that is electrically controlled. In this study, several simulations and experiments are conducted on a 1-link arm without collision. We investigate the effects of energy dissipation and confirm high-speed reverse control in a 1-link arm.