Stable walking of an underactuated bipedal robot with unbalanced masses using one actuator

Abstract

The objective of the research is a stable gait generation on the level ground and some sloping ground of the 3-link biped robot with unbalanced masses using one actuator. We know the biped robot need actuator for stable walking on level ground. A biped robot with a torso model at least two actuators to achieve a stable walk. In the research we have investigated the only one motor which is very much challenging to achieve stable walking gait without the robot falls down, also there is used unbalanced masses where is very much difficult to achieve balanced walking. In this research, the numerical simulations show the robot with unbalanced masses can walk efficiently on level ground by only using one actuator. The robot can generate 2-period and 4-period gait without fall down. First, we introduced the 5-DOF (Degree of freedom) unbalanced masses model where used one actuator that walks the level ground. Second, describes the control system of Proportional-derivative (PD) controller between stance leg and torso, while the swing leg does not use any actuator and it does remain free. Third, we perform numerical simulations and show that the robot can generate a stable walk on level ground and some sloping ground by using one actuator. Furthermore, we conduct some parametric study to investigate the more natural human-like motion of the robot and achieved different results.