Dynamic Analysis of a 7 DOF Robot Using Fuzzy Logic for Inverse Kinematics Problem

Abstract

In this paper, a dynamic analysis for a redundant, serial robot, with seven degrees of freedom is presented. The dynamic model of the robot is based on importing a tri-dimensional CAD model of the robot into MATLAB®, Simulink®-Simscape™-SimMechanics™. One can import complete CAD assemblies, including all masses, inertias, joints, constraints, and tri-dimensional geometries, into the model. The first step for executing a dynamic analysis is to resolve the Inverse Kinematics (IK) problem for the redundant robot. Because this type of robot has seven degrees of freedom the IK resolution implies an infinite number of solutions. So, to be able to resolve the IK for this kind of robot a Fuzzy Logic (FL) technique is used for redundancy resolution. The entire IK resolution is based on a fact that one degree of freedom is determined using FL. Solving the inverse kinematics problem is a mandatory step in the dynamic analysis of the robot, this is required to drive the robot on certain user-imposed trajectories. The dynamic model of the robot is necessary to determine and analyse joint torques so one can reconstruct the fuzzy model with new rules. Reconstructing the fuzzy model would lead to joint torques minimization and efficiency in robot operation. Also, the dynamic model of the redundant robot is necessary for the simulation of motion, analysis of the robot’s structure and design of optimal control algorithms. This will be presented in some further research.