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A robust H\infty sliding mode descriptor observer for simultaneous state and disturbance estimation of uncertain system is developed. Inspired by a singular system theory, a descriptor observer design is presented to estimate some class of output disturbances. A sliding mode scheme is used for the observer to reconstruct the input fault based on the transformed coordinate system. Simulation study illustrates the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

ABSTRACTThis paper presents a vibration reducing technique concerning motion-induced vibration of a flexible manipulator. The proposed method uses a wheel-like rigid body as a torque generator. When this torque wheel drives along a specified path, the reduction of vibration occurs as the torque cancels the motion-induced force. In this study, the manipulator moves along its prescribed rigid-body motions. Even if the manipulator has nonlinear coupling terms, these can be changed to linear time varying terms. To reduce the order of motion induced force, an instantaneous modal coordinate is introduced to the linear time varying system. A wheel driving torque at specific time t* can be calculated in the modal space. The torque profile is synthesized with discrete torque values. This technique was tested both numerically and experimentally. In the experimental part, the control system to reduce the vibration was designed by combining the prescribed joint motions and the feedforward compensation of the torque wheel.

The substnicturing technique is used to analyze the motion of a flexible vehicle structure with nonlinear force elements. The number of effective degrees of freedom of the combined system model is greatly reduced by synthesizing the individually modeled substructures, using constraints of geometric compatibility at the interfaces. When combining the substructures, recursive-type nonlinear integral equations (NIE) are introduced instead of the conventional nonlinear differential equations (NDE). It is shown that the NIE formulation is computationally more efficient than the NDE formulation in simulating steady-state and transient responses of a flexible vehicle with nonlinear dampers. The NIE formulation is further applied to the nonlinear damping optimization problem, and it is found that this method is efficient for optimization.