System centroid position based tipover stability enhancement method for a tracked search and rescue robot

Tipover may cause fatal damages to the mobile robot system during obstacle crossing or stair climbing, and the system centroid position (SCP) is very important for the tipover stability. By monitoring the SCP, it is possible to estimate the risk of tipover and take appropriate actions to prevent the incident from happening. This paper proposes a new tipover avoidance method for enhancing the tipover stability of a tracked mobile manipulator by online adjusting the SCP. The tipover stability criteria for the robot are discussed based on the orientation data from a three-axial gyroscope and the SCP calculation. The velocity kinematic model of the manipulator for SCP adjustment is also presented in this paper. In addition, a redundancy resolution method is employed in order to improve the performance of the robot. The proposed method is applied to a search and rescue robot consists of a four degree of freedom manipulator and a tracked mobile base, and the effectiveness of this method is demonstrated by experimental results.