Quasi-Adaptive Sliding Mode Motion Control of Hydraulic Servo-Mechanism With Modeling Uncertainty: A Barrier Function-Based Method

Zhenle Dong,Jianwei Ma

doi:10.1109/access.2020.3014146

Zhenle Dong, Jianwei Ma

Open Access

https://doi.org/10.1109/access.2020.3014146

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Abstract

This research focuses on motion control of hydraulic servo-mechanism and presents a novel quasi-adaptive sliding mode control algorithm with barrier function-based control gain. The mathematical model of the system is established in integral series format to contribute to the controller design. The utilized sliding mode control gain is designed to be adapted with the change of design error related to tracking error. It can first increase until the design error reaches to a small domain at a designed time by utilizing constant gain. And then the control gain will automatically switch to barrier function form to hold design error within a predefined domain un-depending on the modeling uncertainties theoretically. Correspondingly, the tracking error will converge to a small domain. The system stability is proved via Lyapunov analysis. By comparing to three classic controllers with motion tracking experiments, the achievable higher tracking accuracy of the proposed new control law are validated sufficiently.

Highlights

Hydraulic servo-mechanism has superiorly feature of high power/weight ratio and can support large force/torque comparing to electric motor counterpart, and can hardly be replaced in modern defense and industrial, such as airborne actuating system [1], weapon follow-up system [2], load simulator [3], shield equipment [4], and so on
Xian et al proposed RISE control [15] and subsequently this ingenious method has been applied in hydraulic servo-mechanism [16] and mechanical systems [9] to enhance the control performance for the significant advantage of guaranteeing the asymptotic stability even the unstructured uncertainties exist
In this research, combined with the property of barrier function, we try to develop a new quasi-adaptive sliding mode control (SMC) for hydraulic servo-mechanism aiming at realizing that the design error can reach to a predefined region, where the control gain can be adjusted online without any details of the upper bound of the lumped unstructured uncertainties

Summary

INTRODUCTION

Hydraulic servo-mechanism has superiorly feature of high power/weight ratio and can support large force/torque comparing to electric motor counterpart, and can hardly be replaced in modern defense and industrial, such as airborne actuating system [1], weapon follow-up system [2], load simulator [3], shield equipment [4], and so on. Hydraulic actuators have its inherent nonlinearities (for example, the flow dynamic of valve port) and various modeling uncertainties (for example, the hard-modeled nonlinear friction, matched or unmatched disturbance, hysteresis [5], and so on), which brings great difficulty to the development of high performance motion tracking controller To tackle these issues, many advanced control methods have been tried. In this research, combined with the property of barrier function, we try to develop a new quasi-adaptive SMC for hydraulic servo-mechanism aiming at realizing that the design error can reach to a predefined region, where the control gain can be adjusted online without any details of the upper bound of the lumped unstructured uncertainties.

PROBLEM FORMULATION AND DYNAMIC MODELS

COMPARATIVE RESULTS

CONCLUSION