DYNAMIC MODELLING AND SIMULATION OF MECHANISMS CONSISTING OF COMBINED CLOSED AND OPEN KINEMATIC CHAINS WITH COMPLIANCE

This dissertation attempts to construct a simple and systematic method to analyse spatial multi-loop mechanisms including real life effects such as joint clearances, lubrication of the joints, joint and link compliances, etc. The method is presented in which the Newton-Euler formulation is used to develop the dynamic equation of each link. Kinematic constraints are not imposed explicitly. Instead, a compliant joint model is used to relate the dynamic reactions between neighboring links and cover real life effects. Compliant joint models for different kinds of joints are derived. The method can handle multiple loop robotic devices where some of the loops are open and others are closed chain mechanisms. The method also results in direct computation of joint reactions during dynamic simulation.; An approach to select an accurate, simple and stable numerical integration scheme to solve these dynamic equations is presented. Methods to determine the integration step size, initial conditions and numerical stability are discussed.; As applications of the method developed herein, the dynamic simulation of a slider-crank mechanism, the Ohio State University Hexapod and Adaptive Suspention Vehicle and a platform type robotic manipulator were carried out. The simulation of the legged machine includes the effects of leg mass and compliance, joint compliance and friction as well as the effects of leg contact with the ground. The trajectory planning, gait patterns of the legged machine and motion control algorithm were discussed. The feet impact effects were investigated. The gyroscopic effects of a flywheel power plant of the legged machine were also explained. The simulation results for the Ohio State University Hexapod walking machine are in close agreement with the existing measured experimental data.