We have been trying to induce a quadruped robot to walk with medium walking speed on irregular terrain based on biological concepts. We propose the necessary conditions for stable dynamic walking on irregular terrain in general, and we design the mechanical system and the neural system by comparing biological concepts with those necessary conditions described in physical terms. A PD controller at the joints can construct the virtual spring-damper system as the visco-elasticity model of a muscle. The neural system model consists of a central pattern generator (CPG) and reflexes. A CPG receives sensory input and changes the period of its own active phase. The desired angle and P-gain of each joint in the virtual spring-damper system is switched based on the phase signal of the CPG. CPGs, the motion of the virtual spring-damper system of each leg and the rolling motion of the body are mutually entrained through the rolling motion feedback to CPGs, and can generate adaptive walking. We report on our experimen...

Adaptive Dynamic Walking of a Quadruped Robot on Irregular Terrain Based on Biological Concepts

The focus of this paper is the problem of foot rotation in biped robots during the single-support phase. Foot rotation is an indication of postural instability, which should be carefully treated in...

Postural Stability of Biped Robots and the Foot-Rotation Indicator (FRI) Point

Pstural Stability of Biped Robots and the Foot-Rotation Indicator (FRI) Point

In this paper, we report on our research for learning biped locomotion from human demonstration. Our ultimate goal is to establish a design principle of a controller in order to achieve natural human-like locomotion. We suggest dynamical movement primitives as a CPG of a biped robot, an approach we have previously proposed for learning and encoding complex human movements. Demonstrated trajectories are learned through the movement primitives by locally weighted regression, and the frequency of the learned trajectories is adjusted automatically by a novel frequency adaptation algorithm based on phase resetting and entrainment of oscillators. Numerical simulations demonstrate the effectiveness of the proposed locomotion controller.

/pdf/learning-from-demonstration-and-adaptation-of-biped-5fcq80lenu.pdf

Learning from demonstration and adaptation of biped locomotion with dynamical movement primitives

http://www.cs.cmu.edu/~cga/walking/nakanishi-ras04.pdf

Learning from demonstration and adaptation of biped locomotion

The authors introduce a control method for dynamic biped walking under unknown external forces and moments. By using this method, they perform walking experiments of real-time control with the biped walking robot WL-12RIII which has a newly developed real-time controller. The result shows that the WL-12RIII realized a 0.64(s/step) dynamic stepping motion under an unknown external force which was rectangular and acting backward on its waist. The maximum force strength was 100(N) and the time width was 0.3(s). And the validity of this control method and the real-time controller was experimentally supported. >

A control method for dynamic biped walking under unknown external force

In this paper, the authors intruduce a control method for dynamic biped walking stabilized with trunk and waist motion. The main algorithm of this method is basad m canputing optimal time trajectories of the trunk and waist by arbitrarily giving trajectories of the foot and the ZMp(Zer0Mcment Point)tll, and an external force pattern before the mbt begins walking. To detennine the optimal tim trajectories of the trunkandwaist, theauthorsuseda performance index including the relative position of the trunk and the waist multiplied by weight coefficients. In 1987 , a bi@ walking robot -1 ZR (Was& Leg - 12 Refined) realized various gaits under rectangular external force in dynamic canplete walking stabilized with trunk and waist motion on a flat floor. 'Ihe maxb force strength duringtheseexperiments was lO[kgfl. The time spent walking was 2.6[s/stepl and the maxi." step length was 0.3tmI.

Dynamic Biped Walking Stabilized With Optimal Trunk And Waist Motion

In 1984, the authors succeeded in attaining dynamic walking on a flat floor using a biped walking robot, WL-10RD. The walking lasted 1.3[sec] with a 0.4[m] step. Moreover, in 1985, the authors accomplished the ascending and descending of stairs and slight inclines using the same robot.

H. Karaki

Papers

A control method for dynamic biped walking under unknown external force

Dynamic Biped Walking Stabilized With Optimal Trunk And Waist Motion

Realization of Dynamic Biped Walking Stabilized with Trunk Motion Under Known External Force