Balance and Posture Control of Legged Robots: A Survey

Legged robots excel in navigating challenging natural environments, such as steep obstructions or wide gaps in the ground. In addition to rough terrain, they may confront unexpected impact forces during their leaping gaits. While facing external disturbances, legged robots should maintain and (if necessary) restore their stability while completing their gaits. To this end, external disturbances and body orientation errors should be identified, and appropriate actions have to be taken to restore the balance of the robot and to provide advantageous landing circumstances. This paper briefly surveys the developments for balance and posture control of legged robots. The primary focus of these studies is on balancing legged robots under external disturbances or performing dynamic gaits. This paper also includes a brief focus on the literature that present research on balance and posture control strategies using the angular momentum approach.