Kinematic analysis and control of a 7-DOF redundant telerobot manipulator

The authors deal with the kinematic analysis and control of a kinematically redundant manipulator, which is the slave arm of a telerobot system recently built at Goddard Space Flight Center (GSFC) to serve as a testbed for investigating research issues in telerobotics. A forward kinematic transformation is developed in its most simplified form, suitable for real-time control applications, and the manipulator Jacobian is derived using the vector cross-product method. Using the developed forward kinematic transformation and quarternion representation of orientation matrices, computer simulation is performed to evaluate the efficiency of the Jacobian in converting joint velocities into Cartesian velocities and to investigate the accuracy of Jacobian pseudoinverse for various sampling times. The equivalence between Cartesian velocities and quarternion is also verified using computer simulation. Three control schemes are proposed and discussed for controlling the motion of the slave-arm end effector