Interaction force measurement of robotic manipulator based on 12DOF force sensor

In robotic force feedback application, the acceleration and deceleration of end manipulator will add additional inertial forces/torques to six-axis wrist force/torque sensors. It is desirable to measure the interaction force of manipulator to its environment for controlling purpose. A 12 DOF (degree of freedom) force/torque sensor, which integrates a six-axis accelerometer in the six-axis wrist force/torque sensor, is designed to solve the problem in this paper. The sensor can measure all the three linear accelerations a_x, a_y, a_z and three angular accelerations a_x, a_y, a_z simultaneously in 3D space besides offering information of the forces F_x, F_y, F_z and the moments M_x, M_y, M_z. We also give a kinetic model of six-axis wrist force/torque sensor while the end manipulator is in dynamic state. And the extraction method for interaction force from six-axis wrist force/torque sensor is presented. Some experiments are carried out to test the sensor and verify the data fusion method. The results show that the sensor could output decoupled interaction force, and identify the state of grasped object.