The Study of Kinematics and Trajectory Planning of 9 DOF Serial Redundant Robotic Manipulator

Chee, Weng Khang (2022) The Study of Kinematics and Trajectory Planning of 9 DOF Serial Redundant Robotic Manipulator. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

Text CHEE WENG KHANG_Thesis.pdf Restricted to Registered users only Download (6MB)

Abstract

space is greater than the dimension of the end effector space. The aim of this project is to propose a solution that can exploit the redundancy of the 9-DOF serial redundant manipulator with a suitable method of solving the kinematic problem and trajectory planning algorithm for the robot. The project was carried out in 4 stages, the first stage was to design the configuration and model of a 9-DOF serial manipulator. Second, the forward kinematics and inverse kinematics algorithm were formulated. Third, the trajectory planning algorithm that included the trajectory of the end effector and the redundant axes were determined and lastly, the formulated kinematics and trajectory planning algorithm were tested in a robotic simulation software. To exploit the redundancy of the 9 DOF robotics manipulator, the robot kinematics model was separated into 2 parts, the 3-DOF part (axis-1 to axis 3) and the 6-DOF part (axis-4 to axis-9) with the axis numbers were assigned from the base frame to the end-effector frame. The forward kinematics of both parts were formulated by homogeneous transformation matrix with D-H parameters. Subsequently, the inverse kinematic problem of the robot was solved by Jacobian-based iterative method where the pseudo-inverse method was applied when approximating the inverse of a Jacobian matrix. To generate the trajectories of motion, point-to-point trajectory planning in Cartesian space was used to form the motion paths for both parts (3-DOF part and 6-DOF part). To test the feasibility of the formulated kinematics solutions for this redundant robot, three experiments were conducted. The first experiment was to command the redundant joints and the end-effector to move following two different predetermined straight line trajectories and the second experiment was conducted where the end-effector was commanded to move in trajectories around a 3D object for 3D inspection while its redundant joints were moving in another trajectory to avoid collision with the object simultaneously. The third experiment, the redundant robot performing its task in a restricted environment while its redundant joints is avoiding obstacle which cannot be achieved by a nonredundant robot (i.e. 6-DOF robot). The results of the experiments showed that the end effector and the redundant joints were able to move along their desired trajectories with negligible position error and the redundant robot can perform its task while avoiding obstacles simultaneously. In conclusion, the formulated kinematics solution of this project was able to control the motions of a 9-DOF redundant serial manipulator moving in two different trajectories simultaneously.