Six-degree-of-freedom industrial robot kinematics analysis and end-effector design optimization

Abstract

In this thesis, using the ABB IRB 120 6R robot as an example, the forward and inverse kinematics of the robot are analyzed, and an end-effector suitable for gripping square and cylindrical workpieces for bin-picking operations is designed and optimized by conducting force analysis. Forward kinematics were solved in MATLAB by utilizing DH-parameters and are verified with MATLAB Simulink Simscape Multibody, and inverse kinematics were solved with the use of a MATLAB script. A four-bar linkage mechanical gripper with a self-locking wormgear drive actuated by a stepper motor, suitable for the ABB IRB 120, was designed for bin-picking 136-gram brass valves, and a 3D CAD model of the gripper was created. Finite Element Analysis was conducted to minimize the weight of the designed parts by using Topology Optimization, resulting in a 10.72% reduction in the end-effector’s weight. The optimized parts were refined for manufacturability, and repeated FE analyses provided a safety factor of approximately 10 at the intended operating position. While the control systems of a robot were not addressed, this thesis serves as a guide for the realistic, manufacturable mechanical design of cost-effective mechanical end-effectors for bin-picking of objects with various uneven surfaces, and for the numerical kinematic analysis of 6-DOF robots.