This work presents an assessment of different control techniques based on Limit Cycle Walking. The study is performed on a two-dimensional kneed bipedal simulator developed with Open Dynamics Engine, which includes realistic configuration of weight allocation, link length, inertia distribution and impacts. The controllers are model-based driven from an analytic 2D kneed biped. Several controllers from the Computed Torque (CT) family together with a Passivity Based controller (PBC) are compared based on their energy efficiency and robustness. The previous controllers are used in their original form, with minor adjustment to handle hybrid systems such as the kneed biped case. PBC proved not suitable for real implementation however a combined strategy between PBC and a soft PD control has shown promising results. PD Computed Torque control also offered high tolerance to disturbances with reasonable energy consumption. Furthermore, the performance of all the controllers showed high dependency on the parameters of the robot.

The aim of this study is to increase the versatility of Limit Cycle Walking (LCW) robots by proposing several ideas to control their velocity. The velocity control methods presented are to be used with Computed-Torque Control (CTC). This controller utilizes a passive reference model walking down a gentle slope which provides the reference trajectory to follow. The controllers were tested on a rigid body simulator. The results show that the methods based on scaling the amplitude (step length) of the reference trajectory and changing the reference slope angle, provide an energy efficient and stable way to control the walking speed. Both of these methods also provide continuous trajectories to standing pose and running gait.