Adaptive Repetitive Control of A Linear Oscillating Motor under Periodic Hydraulic Step Load.

Xinglu Li,Yuan Cao,Yang Li,Zongxia Jiao

doi:10.3390/s20041140

Xinglu Li, Yuan Cao + Show 2 more

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https://doi.org/10.3390/s20041140

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Abstract

A linear oscillating motor has a direct and efficient linear motion output and is widely used in linear actuation systems. The motor is often applied to compact hybrid electrohydraulic actuators to drive a linear pump. However, the periodic switch of the rectification valve in the pump brings the hydraulic step load to the linear motor, which causes periodic oscillation waveform distortions. The distortion results in the reduction of pumping capacity. The conventional feedback proportional-integral-derivative control is applied to the pump, however, this solution cannot handle the step load as well as resolving nonlinear properties and uncertainties. In this paper, we introduce a nonlinear model to identify periodic hydraulic load. Then, the loads are broken up into a set of simple terms by Fourier series approximation. The uncertain terms and other modeling uncertainties are estimated and compensated by the practical adaptive controller. A robust control term is also developed to handle uncertain nonlinearities. The controller overcame drawbacks of conventional repetitive controllers, such as heavy memory requirements and noise sensitivity. The controller can achieve a prescribed final tracking accuracy under periodic hydraulic load via Lyapunov analysis. Finally, experimental results on the linear oscillating motor-pump are provided for validation of the effectiveness of the scheme.

Highlights

Compact hybrid electrohydraulic actuators have been widely reported in literature in recent years [1]
Liang et al [4] developed a tubular linear oscillating motor to use in the electro-hydrostatic system
Based on adaptive robust control (ARC), we developed adaptive robust repetitive control schemes that solve the problematic heavy memory requirements and noise sensitivity [21,22]

Summary

Introduction

Compact hybrid electrohydraulic actuators have been widely reported in literature in recent years [1]. The actuator consists of a pump driven by piezoelectric stacks. The inherent low amplitude of the piezoelectric stack hinders improvement of the flow rate [2,3]. The linear oscillating motor can achieve the oscillation motion of a relatively large amplitude and is considered as the driver of electro-hydrostatic systems. Liang et al [4] developed a tubular linear oscillating motor to use in the electro-hydrostatic system. Wang et al [5] optimized the linear oscillating motor, which achieved a high thrust and eliminated the eddy current effect. Based on the linear oscillating motor, Li et al [6] developed the linear drive collaborative rectification structure pump (LDP). Jiao et al [7] invented the linear drive electro-hydrostatic actuator and experiments were conducted. The output cylinder produces the highest no-load output velocity of 62.2 mm/s and a maximum work pressure of 2.2 MPa [8]

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