Variable Admittance Control of Robot Manipulators Based on Human Intention

This paper presents a variable admittance control method to achieve intuitive human-robot interactions that consider human intentions. Human intention is classified into two categories-direct and indirect. With respect to direct intention, the concept of standard force is introduced to adjust the interacting force. The proposed variable admittance control method improves intuitiveness when velocity is used as an estimate of direct intention. In the estimation of indirect intention, a force guidance method is suggested to make a robot follow and guide a human. The proposed control methodology is adapted to a six-DOF manipulator based on a one-dimensional analysis. The experiments are conducted with a manipulator (Universal Robots, UR10) and a force/torque sensor (Robotus, RFT60-HA) to evaluate the performance. The experiments validate that variable admittance control enhances the execution time, accuracy, and comfort of the operator.