This paper presents an approach to control gaits of humanoid bipedal robots in operational space without reference trajectories. This control strategy is based on the planning of the sequential events during the walking process. The aim of this study is to propose a new control strategy which is more reactive, permits a precise coordination of both legs during the double stance phase and the generation of dynamic 3D walking of an anthropomorphic biped with flexible feet. Based on homogeneous transformation matrices, the control strategy integrates three aspects in one unified representation: structural parameters of the robot, measurements given by sensors, planning of the sequential events during the different stages of the walk.

This paper presents a new approach to control gaits of humanoid bipedal robots in the operational space. This strategy based on the homogeneous transformation matrices integrates, in a unified representation, the structural aspects of the robot, the reference trajectories based on motion capture, the measures given by the robot sensors, the locomotion constraints and the high-level control using desired trajectories modified at each sample time. This approach is applied on a biped with flexible feet walking with an average speed equal to 1.2 m/s.

In this paper, we present the 3D dynamic simulation of walking gait of biped Robian II virtual manikin. The biped has 16 degrees of freedom (DOFs). Initially, a biomimetic approach is used to model a humanoid biped having 25-DOFs based on common European male (75 kg, 1.78 m). Using human being motion recording, foot/ground contact model and inverse kinematics, a 3D dynamic simulation of this humanoid is carried out. Scale factorization is used in order to reach Robian II weight and height. A 3D dynamic simulation of the Robian size humanoid gives the effort wrench exerted by the torso on the lower limbs. An analysis of the six components of this wrench shows the existence of two coupling relations. A study of four DOFs mechanisms based on the general state equation formalism leads us to an interesting result. Indeed, four DOFs are necessary and sufficient to emulate the dynamic effects. A RPPP mechanism is presented in order to replace Robian's upper part. Results of 3D simulation of the 16-DOFs resulting biped are presented. The ZMP control algorithm is used to ensure dynamic stability of the biped during walking gait.