Fall Avoidance and Recovery for Bipedal Robots using Walking Sticks

For humanoid robots to replace humans in dangerous environments, they require a robust fall prevention system that can detect falls, prevent major damage and recover back up to continue on with the task. This paper introduces a system that is capable of fall detection, mitigation and recovery in a robot equipped with walking sticks. Walking sticks allow the humanoid robot to extend its support polygon in a fall. Using IMU data and kinematics, the orientation of the robot is used to detect if external disturbances would cause a fall. The required position of the walking stick tips are calculated to minimise the angle fallen before the system is deployed. A recovery sequence is generated to recover the robot to a stable state prior to the disturbance. Hardware experiments on the Robotis OP2 found the system was capable of reducing the impact shock for forward falls while standing and walking.