This paper employs nonlinear disturbance observer (NDO) for robust trajectory-free Nonlinear Model Predictive Control (NMPC) of biped robots. The NDO is used to reject the additive disturbances caused by parameter uncertainties, unmodeled dynamics, joints friction, and external slow-varying forces acting on the biped robots. In contrary to the slow-varying disturbances, handling sudden pushing ...

this paper employs nonlinear disturbance observer (ndo) for robust trajectory-free nonlinear model predictive control (nmpc) of biped robots. the ndo is used to reject the additive disturbances caused by parameter uncertainties, unmodeled dynamics, joints friction, and external slow-varying forces acting on the biped robots. in contrary to the slow-varying disturbances, handling sudden pushing ...

In this increasingly aging society, the needs for robots to assist human activities in daily environments such as offices, homes, and hospitals are growing rapidly. In such environments originally designed for human beings, biped robots, which have almost the same mechanisms as a human, present many advantages than wheeled robots like obstacle avoidance capabilities for its possibility of disco...

Legged robots have been studied and developed for a long time. The primary advantage of legged motion is that they can traverse terrains inaccessible to wheeled robots. Biped robots are probably the most complicated of legged robots. Despite their complexity there has been a substantial amount of work done in the field including different techniques that have been developed to model, design and...

stability and performance are two main issues in motion of bipeds. to ensure stability of motion, a biped needs to follow specific pattern to comply with a stability criterion such as zero moment point. however, there are infinity many patterns of motion which ensure stability, so one might think of achieving better performance by choosing proper parameters of motion. step length and step perio...

this paper proposes a gait planning approach to reduce the required friction for a biped robot walking on various surfaces. to this end, a humanoid robot with 18 dof is considered to develop a dynamics model for studying various 3d manoeuvres. then, feasible trajectories are developed to alleviate the fluctuations on the upper body to resemble human-like walking. in order to generate feasible w...

Abstract: This paper presents a robust control method via the intelligent adaptive backstepping design technique for stable walking of nine-link biped robots with unknown model uncertainties and external disturbances. In our control structure, the self recurrent wavelet neural network (SRWNN) which has the information storage ability is used to observe the uncertainties of the biped robots. The...

Biped robots have specific dynamical constraints and stability problems which reduce significantly their motion range. In these conditions, motion planning used for mobile robots cannot be applied to biped robots. In this paper, the path planning problem is seen as finding a sequence of footholds in a 3D environment, keeping robot stability, motion continuity and working within the structural c...

Biped robots are expected to walk on many di erent and previous unknown terrains, and thus they may walk on a slippery surface with low friction with no information on the surface a priori. Any fall-down due to unexpected slipping could costly damage the robot and thus should be avoided. This paper proposes a re ex control method for biped robots to quickly recover their posture from a slip soo...

Different approaches have been briefly overviewed which have been used in stability of biped robots. Current implementations either mimic human behavior or use heuristic control. This paper suggests the use of modelfree crisp control in operational space configuration for better control and understanding of kino-dynamic systems and biped robots.