Adaptation of the inverse kinematics of the DLR light weight
robot for its use as haptic device

Abstract: Haptic devices play an important role in haptic applications. Light Weight
Robot III is the latest version of DLR light weight robot. It has seven
Degree of Freedom (DoF) with only 14 kg self weight. Seven torque sensors
mounted on its joints and one 6 DoF force-torque sensor on the end-effector
enable it to precisely sense the external forces. Existing inverse
kinematics library is design for a general model of Light Weight Robot III,
which is slightly dierent from the one used as haptic device. This thesis
is intended to adapt and optimize this inverse kinematics library for the
haptic applications of Light Weight Robot III. It describes the adaptation
of the inverse kinematics library to the hardware, which conquered the
problems caused by the different configuration of the robot used as haptic
device. It realized the null space movement of the robot, which enables the
position changing of the intermediate joints due to applied force on it. At
last it gives a solution for detecting and avoiding the singular
configurations of the robot, which is especial important due to
unpredictable trajectory of the end-eector. The simulation and experiment
results of improved kinematics library are also shown in this thesis.