In this paper an H∞ controller is designed for a hydraulically actuated active suspension system of a half-modeled vehicle in a cascade feedback structure. Using the proposed structure the nonlinear behavior of actuator is reduced significantly. In the controller synthesis, a proportional controller is used in the inner loop, and a robust H∞ controller forms the outer loop. Two H∞ controllers a...

This paper deals with the challenging aspect concerning the state estimation in hydraulic actuators characterized by not negligible nonlinearities. Particularly,. One of the most common hard nonlinearities in hydraulic actuator is the deadzone. More specifically, dead-zone occurs in hydraulic control valves when its spool occludes the orifice with an overlap, so that for a range of spool positi...

This paper presents a novel approach to the design of road adaptive active suspensions via a combination of linear parameter-varying control and nonlinear backstepping techniques. Two levels of adaptation are considered: the lower level control design shapes the nonlinear characteristics of the vehicle suspension as a function road conditions, while the higher level design involves adaptive swi...

Massive actuator arrays found their applications in robotics, pharmaceutics, aerospace, etc. Compared with electrically and/or pneumatically powered actuator array, hydraulic actuator has the comprehensive advantages of higher force density (i.e. force / actuation area), better controllability, and simpler remote control accessibility. This paper presents approaches to construct and control a m...

A position-based impedance controller is proposed and demonstrated on an existing hydraulic press with a two-way vertically mounted hydraulic cylinder driven by a servo-solenoid valve. A proportional-integral-derivative (PID) controller and a Fuzzy Logic Controller (FLC) are primarily developed to meet the accurate positioning requirements of the impedance control formulation. The impedance fil...

The rst part of this thesis includes a brief comparison between electricmotors and hydraulic actuators for high performance robotics applications. Hydraulic actuators with fast valves are shown to be superior because of their large torque to mass ratios and their extended bandwidth. One such hydraulic actuator is characterized and its highly nonlinear dynamics are modeled and identi ed. A simul...

In this paper, the investigational results for a robust adaptive vibration control of a translating tensioned beam with a varying traveling speed are presented. The dynamics of the moving beam are modeled as an Euler-Bernoulli beam, in which the tension applied to the beam is given as a nonlinear spatiotemporally varying function. The moving beam span is divided into two parts, i.e., a controll...

This article presents the design of a robust force controller for a hydraulic actuator interacting with an uncertain environment via quantitative feedback theory (QFT). After the derivation of a realistic nonlinear differential equation model, a linearized plant transfer function is developed. The effects of nonlinearities are accounted for by describing the linearized model parameters as struc...

Neural network black-box modeling is usually performed using nonlinear inputoutput models. The goal of this paper is to show that there are advantages in using nonlinear state-space models, which constitute a larger class of nonlinear dynamical models, and their corresponding state-space neural predictors. We recall the fundamentals of both input-output and state-space black-box modeling, and s...

Neural network black-box modeling is usually performed using nonlinear input-output models. The goal of this paper is to show that there are advantages in using nonlinear state-space models, which constitute a larger class of nonlinear dynamical models, and their corresponding state-space neural predictors. We recall the fundamentals of both input-output and state-space black-box modeling, and ...