scholarly journals Delay compensation based controller for rotary electrohydraulic servo system

2021 ◽  
Author(s):  
Zakarya Omar ◽  
Xingsong Wang ◽  
Khalid Hussain ◽  
Mingxing Yang
Keyword(s):  
High Frequency ◽  
Dead Time ◽  
Sliding Mode ◽  
Servo System ◽  
Smith Predictor ◽  
Delay Compensation ◽  
Mechanical Parts ◽  
System Output ◽  
Electrohydraulic Servo System ◽  
The Stability

AbstractThe typical power-assisted hip exoskeleton utilizes rotary electrohydraulic actuator to carry out strength augmentation required by many tasks such as running, lifting loads and climbing up. Nevertheless, it is difficult to precisely control it due to the inherent nonlinearity and the large dead time occurring in the output. The presence of large dead time fires undesired fluctuation in the system output. Furthermore, the risk of damaging the mechanical parts of the actuator increases as these high-frequency underdamped oscillations surpass the natural frequency of the system. In addition, system closed-loop performance is degraded and the stability of the system is unenviably affected. In this work, a Sliding Mode Controller enhanced by a Smith predictor (SMC-SP) scheme that counts for the output delay and the inherent parameter nonlinearities is presented. SMC is utilized for its robustness against the uncertainty and nonlinearity of the servo system parameters whereas the Smith predictor alleviates the dead time of the system’s states. Experimental results show smoother response of the proposed scheme regardless of the amount of the existing dead time. The response trajectories of the proposed SMC-SP versus other control methods were compared for a different predefined dead time.

Discrete-Time H-Infinity Synthesis of Frequency-Shaped Sliding Mode Control for Suppression of Vibration With Multiple Peak Frequencies

2016 ◽  
Author(s):  
Minghui Zheng ◽  
Masayoshi Tomizuka
Keyword(s):  
High Frequency ◽  
Sliding Mode ◽  
Disk Drive ◽  
Sliding Surface ◽  
Surface Dynamics ◽  
H Infinity ◽  
High Frequencies ◽  
Multiple Peak ◽  
Significant Performance ◽  
The Stability

Vibration with multiple large peaks at high frequencies may cause significant performance degradation and have become a major concern in modern high precision control systems. To deal with such high-frequency peaks, it is proposed to design a frequency-shaped sliding mode controller based on H∞ synthesis. It obtains an ‘optimal’ filter to shape the sliding surface, and thus provides frequency-dependent control allocation. The proposed frequency-shaping method assures the stability in the presence of multiple-peak vibration sources, and minimizes the weighted H∞ norm of the sliding surface dynamics. The evaluation is performed on a simulated hard disk drive with actual vibration sources from experiments, and the effectiveness of large vibration peak suppression is demonstrated.

scholarly journals Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yan Ren ◽  
Zhenghua Liu ◽  
Le Chang ◽  
Nuan Wen
Keyword(s):  
Robust Control ◽  
High Frequency ◽  
Disturbance Observer ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Tracking Error ◽  
Servo System ◽  
Adaptive Sliding Mode ◽  
Main System

A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mode robust control method based on the improved disturbance observer. The sliding mode technique helps this disturbance observer to deal with the uncompensated disturbance in high frequency by making use of the rapid switching control value, which is based on the subtle error of disturbance estimation. Besides, the high-frequency chattering is alleviated effectively in this proposal. The effectiveness of the proposal is confirmed by experiments on optoelectric tracking platform.

Simulation for Pole Placement in Textile Machinery Electrohydraulic Servo System

2012 ◽  
Vol 569 ◽  
pp. 482-486 ◽  
Author(s):  
Jun Yan Xu
Keyword(s):  
Output Feedback ◽  
Control Method ◽  
Servo System ◽  
State Parameter ◽  
Pole Placement ◽  
System State ◽  
Accuracy Requirement ◽  
Electrohydraulic Servo System ◽  
The Stability ◽  
Stability And Accuracy

The observer for reflecting the system state parameter has been designed according to the stability and accuracy requirement of electrohydraulic servo system. With pole placement done by the observer, it greatly improves the system performance compared with the widely used output feedback adjustment control method.

Dynamic Sliding Mode Control Scheme for Electro-Hydraulic Velocity Servo System

2013 ◽  
Vol 798-799 ◽  
pp. 598-602
Author(s):  
Qi Zhang ◽  
Jing Dong Zhang ◽  
Rui Tang
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Servo System ◽  
Mode Control ◽  
Control Quality ◽  
Model Control ◽  
Dynamic Sliding Mode Control ◽  
The Stability ◽  
Dynamic Sliding Mode

Pointing on uncertainties in the velocity servo system, caused by servo system cant model accurately, may cause the deterioration of the control quality of the electro-hydraulic servo system, and even lead to its instability. Sliding model control (SMC) strategy has been application in electro-hydraulic velocity servo control. Given that the quality and stability of servo system will be affected by the chartering phenomenon in the SMC, this paper proposes an approach to overcome the chattering: dynamic sliding mode control (DSMC). In this paper the mathematical model is established and the dynamic sliding mode controller is designed. Simulation and experiment indicated that: the proposed control strategy has good performance on velocity tracking and chattering reducing .The stability and control quality of the servo system are improved.

Global Robust Terminal Sliding Mode Control for PMLSM Servo System

2013 ◽  
Vol 273 ◽  
pp. 280-285 ◽  
Author(s):  
Hong Pei Han ◽  
Wu Wang ◽  
Zheng Min Bai
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
External Load ◽  
Sliding Mode ◽  
Servo System ◽  
Lyapunov Theory ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
The Stability

Permanent Magnet Linear Synchronous Motor (P MLSM was hard to control with traditional control strategy for parameters variation and external load disturbance, a global robust terminal sliding mode control (GRTSMC) was designed for PMLSM servo system, the sliding mode surface function was designed, the robust sliding mode control law was deduced and the stability was proved by Lyapunov theory. With the mathematical models of PMLSM, the simulation was taken with traditional PID control, SMC control and GRTSMC control proposed in this paper, the robust performance be found with GRTSMC control when motor parameters and external load changed, the efficiency and advantages of this robust control strategy was successfully demonstrated.

scholarly journals Dynamic output feedback sliding mode control for uncertain linear systems

2021 ◽  
pp. 014233122110507
Author(s):  
Jiehua Feng ◽  
Dongya Zhao ◽  
Xing-Gang Yan ◽  
Sarah K Spurgeon
Keyword(s):  
Sliding Mode Control ◽  
Linear Systems ◽  
Output Feedback ◽  
Sliding Mode ◽  
Sliding Surface ◽  
Mode Control ◽  
Sliding Motion ◽  
System Output ◽  
The Stability ◽  
Uncertain Linear Systems

In this paper, a class of uncertain linear systems with unmatched disturbances is considered, where the nominal system representation is allowed to be non-minimum phase. A sliding surface is designed which is dependent on the system output, observed state, and estimated uncertain parameters. A linear coordinate transformation is introduced so that the stability analysis of the reduced-order sliding mode dynamics can be conveniently performed. A robust output feedback sliding mode control (OFSMC) is then designed to drive the considered system state to reach the sliding surface in finite time and maintain a sliding motion thereafter. A simulation example for a high incidence research model (HIRM) aircraft is used to demonstrate the effectiveness of the proposed method.

scholarly journals Sliding Mode Force Control of an Electrohydraulic Servo System with RBF Neural Network Compensation

Mechanika ◽  
2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Xinliang LU ◽  
Fengpo DU ◽  
Qian JIA ◽  
Bin Ren ◽  
Xingsong WANG
Keyword(s):  
Neural Network ◽  
Force Control ◽  
Sliding Mode ◽  
Rbf Neural Network ◽  
Servo System ◽  
Electrohydraulic Servo System
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