A new method for adaptive-fuzzy control achieves stabilization of a quadrotor helicopter in the presence of sinusoidal wind disturbance. Techniques traditionally used in adaptive control for robust parameter updates may not be sufficient for fuzzy schemes. In particular, e-modification may result in the fuzzy-membership centers drifting to large values when persistent oscillations are present in the input. These large values can cause control signal chatter, which can be undesirable or even cause instability if they excite unmodeled dynamics. A new method for robust updates is proposed that prevents this drift in the fuzzy membership centers. In the new method, a set of alternate membership function centers guides the adaptation process in order to prevent drift. A Lyapunov-stability proof ensures the uniform ultimate boundedness of all signals. A simulation of a quadrotor helicopter demonstrates the high performance and robust stability of the new method

This work presents a unifying framework to study energy-efficient optimal gaits for a bipedal model without elastic elements. The model includes a torso, flat feet, and telescoping legs, equipped with rotational hip and ankle joints. Two general types of gaits are studied: with and without a flight phase. The support surface can be level ground, sloped, or staircase. The algorithm achieves the optimum within the admissible space by using a minimal set of realistic physical constraints, and avoiding a priori assumptions on kinetic and kinematic parameters such as extended or instantaneous double-support, collisional or collisionless foot-ground contact, step length, step period, etc. The gait optimization for this simple model predicts many features of human locomotion including the optimality of pendular walking and impulsive running at slow and fast progression speeds, ankle push-off prior to touch-down, swing leg retraction, landing on a near vertical leg in gaits with flight phase, and burst hip torques at both ends of the swing phase.

Robots are becoming increasingly relevant to neurosurgeons, extending a neurosurgeon's physical capabilities, improving navigation within the surgical

The nonlinear and open-loop unstable dynamics of a quadrotor helicopter makes a control system design non-trivial. However, even more difficulty lies in adapting to an uncertain dynamic model and unknown payloads while remaining robust to significant