Kinematics Analysis and Tracking Control of Novel Single Actuated Lizard Type Robot

The purpose of this paper is to propose a new type of a kinetic chained walking robot capable of walking with only a single actuator, and is to design its trajectory tracking control system. Legged robots are able to move across irregular terrains, however, have an issue on energy efficiency compared with other morphology. A bio-inspired approach often provides effective solutions, for example, a lizard is able to mainly walk by utilizing only twisting its waist. To mimic this characteristic by robotics, a robot consisting of four-bar linkage mechanism is proposed. This idea improves simplification of its locomotion analysis. In this paper, two important kinematics characteristics are analyzed in order to propose locomotion ability and effectiveness of the robot. In particular, a turning angle and a stride distance are analysed. After that, a trajectory tracking control system is designed based on the PID control low. Ideas for the control system design in this paper are both to decide an bias of an input angle function as a input of the system and to set a control period on half period of the input angle function. Finally, effectiveness of the designed control system is verified via numerical simulations. A straight line and a circle trajectory are adopted for the verification. As the results, it is shown that the designed trajectory tracking control system is capable of tracking two different trajectory. In addition, it is also shown that the designed trajectory tracking control system satisfies the kinematics analysis results from the side of view of the kinematic of the robot.