A robust hybrid control strategy for a broad class of hybrid nonlinear processes with actuator constraints and uncertain dynamics is proposed. These ®ariable-structure processes comprise a finite family of constrained uncertain continuous nonlinear dynamical subsystems, together with discrete e®ents that trigger the transition between the continuous subsystems. The proposed control strategy is ...

Series elastic actuators have a spring intentionally placed at the actuator output. Measuring the spring strain gives an accurate measurement for closed-loop actuator force control. The low spring stiffness allows for high control gain while maintaining actuator stability. This gives series elastic actuators many desirable properties including high bandwidth at moderate force amplitudes, low ou...

Abstract: The paper presents a new control strategy for active vehicle suspensions using electrohydraulic actuators based on Takagi-Sugeno (T-S) fuzzy modelling technique. As the electrohydraulic actuator dynamics is highly nonlinear, the T-S fuzzy modelling technique using the idea of “sector nonlinearity” is applied to exactly represent the nonlinear dynamics of electrohydraulic actuator in a...

A new dynamic model is presented for piezoelectric tube actuators commonly used in high-precision instruments. The model captures coupling between motions in all three axes such as bending motion due to a supposedly pure extension of the actuator. Both hysteresis and creep phenomena are included in the overall actuator model permitting modeling nonlinear sensitivity in the voltage to displaceme...

The structured singular value ( ) synthesis technique is used to design controllers for the Active Mass Damper (AMD) Benchmark problem. In addition to stated performance objectives, robustness of the controllers to high frequency unmodeled dynamics (the neglected high frequency modes of the evaluation model), modeling error in the actuator dynamics and variations in the rst structural natural f...

In this study, a new servo control system is presented for the overhead crane based on discrete-time state feedback approach. It provides both robust tracking and load swing suppression. Inspired from independent joint and computed torque control in robot manipulator field, a new model is derived in which the crane actuators are considered as the main plant. The crane nonlinearities are then tr...

An analytical solution for a sandwich circular FGM plate coupled with piezoelectric layers under one-dimension heat conduction is presented in this paper. A nonlinear static problem is solved first to determine the initial stress state and pre-vibration deformations. By adding an incremental dynamic state to the pre-vibration state, the differential equations are derived. The role of thermal en...

Today, robots and unmanned aerial vehicles are being used extensively in modern societies. Due to a wide range of applications, it has attracted much attention among scientists over the past decades. This paper deals with the problem of the stability of a four-rotor flying robot called quadrotor, which is an under-actuated system, in the presence of operator or sensor failures. The dynamica...

1 With guided-wave approaches becoming prevalent for structural health monitoring, the need has arisen for more effective models employing these methods using piezoelectric transducers. This paper describes an analytical formulation to couple transducer dynamics with axisymmetric guided-wave excitation models for isotropic plates. The finite-dimensional piezo-actuator dynamics are modeled using...