Apparatus and method for balancing and damping control in whole body coordination framework for biped humanoid robot
Apparatus and a method for balancing and damping control in whole body coordination framework for a biped humanoid robot. The method comprises the steps of: (a) damping the structural vibration of the main body of the robot caused when the robot walks; (b) compensating for the trajectories of the zero moment position (ZMP) and the center of mass (COM) of the robot which changes in accordance with the damping of the structural vibration; and (c) compensating for the body orientation of the robot which changes in accordance with the damping of the structural vibration and the trajectory of the COM.
1. A method for balancing and damping control in a whole body coordination framework for a biped humanoid robot including a main body and a plurality of limbs, the method comprising the steps of:
(a) damping, by a damping controller, structural vibration of the main body of the robot caused when the robot walks;
(b) compensating for trajectories of a zero moment position (ZMP) and the center of mass (COM) of the robot which change in accordance with the damping of the structural vibration;
(c) compensating for a body orientation of the robot which changes in accordance with the damping of the structural vibration and the trajectory of the COM;
(d) designing a desired trajectory of an angular velocity of the main body of the robot as expressed by the following equation:
ω ref =ω d +T (φ){ k p (φ d −φ)+ k I ∫(φ d −φ) dt}
where φ represents a body orientation angle, φ d represents a desired body orientation angle, k p and k I are coefficients of PI control, T(φ) represents a transformation matrix, ω ref represents a reference angular velocity, and ω d represents a desired angular velocity of the main body of the robot; and
outputting the desired trajectory of the angular velocity of the main body of the robot to the robot to stabilize the body orientation of the robot through feedback control.
2. The method according to claim 1 , wherein in step (b), the robot is excited in a frequency band of interest by Δx and Δy to obtain a transfer function expressed by the following equation, and the transfer function is used to compensate for the ZMP:
ZMP Δx =a x x Δcr −b x {umlaut over (x)} Δcr , ZMP Δy =a y y Δcr −b y ÿ Δcr
where a i and b i are parameters of the transfer function.
3. An apparatus for balancing and damping control in a whole body coordination framework for a biped humanoid robot including a main body and a plurality of limbs, the apparatus comprising:
a ZMP controller;
a COM controller;
a PID controller;
a damping controller that damps a structural vibration of the main body of the robot caused when the robot is walking; and
a body orientation compensator that compensates for a body orientation of the robot which changes in accordance with the damping of the structural vibration;
wherein the body orientation compensator designs a desired trajectory of an angular velocity of the main body of the robot as expressed by the following equation:
ω ref =ω d +T (φ){ k p (φ d −φ)+ k I ∫(φ d −φ) dt}
where φ represents a body orientation angle, φ d represents a desired body orientation angle, k p and k I are coefficients of PI control, T(φ) represents a transformation matrix, ω ref represents a reference angular velocity, and ω d represents a desired angular velocity of the main body of the robot.
4. The apparatus according to claim 3 , further comprising:
a ZMP compensator that compensates for trajectories of ZMP and COM in accordance with movement of the robot,
wherein the body orientation compensator compensates for the body orientation of the robot on the basis of the damping of the structural vibration and the compensated trajectories of COM and ZMP.