Acceleration compensation for biped robots to reject external disturbances

The disturbance rejection problem associated with practical biped robots is studied. When the biped robot receives an external disturbance, robot joints suffer abrupt velocity changes. This causes angular velocity of the supporting angle (the angle between the supporting foot and ground) to deviate from 0°, which makes the robot unstable. To reject external disturbances, a strategy called acceleration compensation is proposed. This strategy uses joint accelerations to impose negative acceleration on the angular velocity of the supporting angle, i.e the acceleration is in the opposite direction to the angular velocity. The angular velocity acquired at the moment of a disturbance can thus be reduced to zero in a minimum amount of time, so the deviation of the supporting angle is minimized. Computer simulation and experimental results are presented that verify the usefulness of the method