Motion Decoupling and Composition via Reduced Order Model optimization for Dynamic Humanoid Walking with CLFQP based Active Force Control In this paper, 3D humanoid walking is decoupled into periodic and transitional motion, each of which is decoupled into planar walking in the sagittal and lateral plane. Reduced order models (ROMs), i.e. actuated Springloaded Inverted Pendulum (aSLIP) models and HybridLinear Inverted Pendulum (HLIP) models, are utilized for motion generation on the desired center of mass (COM) dynamics for each type of planar motion. The periodic motion is planned via point foot (underactuated) ROMs for dynamic motion with minimum ankle actuation, while the transitional motion is planned via footactuated ROMs for fast and smooth transition. Composition of the planar COM dynamics yields the desired COM dynamics in 3D, which is embedded on the humanoid via control Lyapunov function based Quadratic programs (CLFQPs). Additionally, the ground reaction force profiles of the aSLIP walking are used as desired references for ground contact forces in the CLFQPs for smooth domain transitions. The proposed framework is realized on a lowerlimb exoskeleton in simulation wherein different walking motions are achieved.

MultiContact Stabilization of a Humanoid Robot for Realizing Dynamic Contact Transitions on Noncoplanar Surfaces This paper focuses on a stabilization control for multicontact motion which enables a humanoid robot to locomote by realizing dynamic contact transitions on nonflat environment. In the stabilization process of the multicontact motion, the desired ZeroMoment Point (ZMP) is modified by the position of the Divergent Component of Motion (DCM) error with respect to the 3D Center of Mass (CoM) motion generated from the force distribution ratio. The contact wrench of each endeffector is determined by quadratic optimization considering the centroidal dynamics and contact friction constraints so as to satisfy the modified ZMP. Each endeffector is controlled by optimized force reference through a projection of null space by force distribution ratio. We propose a multicontact stabilization framework which can be designed not only to generate 3D CoM motion but also the CoM position estimation and the optimal force distribution around the reference ZMP in a unified manner from a balance controller, by using the force distribution ratio. The effectiveness of proposed method is validated by a quadruped locomotion leaning against a vertical wall using the joint position controlled humanoid HRP5P in a dynamic simulator.