Multibody Dynamics and Control of Flexible Biped Robots with Wheeled Feet

This thesis provides three solutions for the objective of controllable distance of the Center of Mass traveled: constant spring stiffness, variable spring stiffness and variable wheel speed. The model in this thesis is flexible biped robot with wheeled, which combines the benefits of legged robot and wheeled robot. At the meanwhile, the wheel provides another way to control/increase the distance of center of mass (C.O.M) traversed in the direction of moving. The thesis deduced the formula of position, speed and acceleration of C.O.M in analytical way based on the inverted pendulum model. By experiment in MATLAB/Simscape, the thesis explanate the necessary of introduction of flexible element. In each solution, four cases of different spring installment are compared: no spring, spring on calf, spring on thigh and two same spring on thigh and calf. The results indicate the feasibility, pros and cons of three solutions and the best position of spring based on the torque and power of angular actuator in each solution. In the end, different input profile (Human running input) is authorized to verify the conclusion.