Shape Memory Alloys (SMA's) are generally considered to be a slow and imprecise means of actuation. With the SMA actuator designed at McGill University we wish to show the contrary. In this paper, several SMA actuators are used to actively damp an external impulse disturbance on a mass to be isolated from vibrations. The vibration isolation testbed consists of a `strong' actuator to low-pass th...

Stability analysis of linear periodically time-varying systems via integral quadratic constraints is extended to the problem of control design. A full-state feedback controller that satis5es exponential stability and L2-gain disturbance attenuation from an external disturbance to a controlled output is designed for linear systems with periodically time-dependent system matrices. The main result...

Teleoperation systems are subject to different types of disturbances. Such disturbances, when unaccounted for, may cause poor performance and even instability of the teleoperation system. This paper presents a novel nonlinear bilateral control scheme using the concept of disturbance observer based control for nonlinear teleoperation systems. Lumping the effects of dynamic uncertainties and exte...

The attitude tracking control problem of a rigid spacecraft with external disturbances is addressed using the concept of extended disturbance and the inverse optimal control method. The proposed attitude tracking control law is inverse optimal with respect to a meaningful cost functional and the associated Lyapunov function satisfies a HamiltonJacobi-Isaacs partial differential equation. Hence,...

This paper addresses the disturbance attenuation problem in nonlinear moving horizon control. Conceptually a minimax formulation with a general dissipation constraint is suggested and theoretical results on closed-loop dissipation, L2 disturbance attenuation and stability are discussed. The implementation issue is attacked with respect to tracking a reference trajectory in the presence of exter...