Evaluation of Three Different Null Space Joint Velocities For a Redundant 5-Bar Linkage Manipulator
In redundant manipulators, there are infinite numbers of joint space velocities that lead to a specific task space velocity. Thus, the main problem is calculating a local maximum for null space joint velocity regarding to physical constraints of a robotic manipulator. The manipulability measure, the distance from mechanical joint limits and the distance from the obstacles are three different cost functions which are evaluated in this paper to find a local maximum for null space joint velocity. It is represented that by using these functions, the redundancy may be exploited to overcome singularities. Furthermore, redundancy can be used to keep the joints of the 5-bar linkage in an acceptable range and can be used to avoid collisions with constant obstacles. Computer simulation results given for a 5-bar linkage manipulator, demonstrate the efficacy of the proposed null space joint velocities. Also it is extracted that accurate trajectory tracking can be achieved by using the well-known controllers.
Keywords- 5-bar linkage; Redundancy; Null Space Joint Velocity; Robotics Manipulator;Denavit-Hartenberg parameters