Synchronization and Tracking Control for Dual‐motor Driving Servo Systems with Friction Compensation

This paper proposes a continuous nonsingular terminal sliding mode (NTSM) control approach for nonlinear systems subject to mismatched terms in order to achieve finite time exact tracking and disturbance rejection. The controller is constructed using a composite method that utilizes a power integrator and combines the output regulation theory, disturbance observation technique, feedback domination and sliding mode control technique. The performance analysis demonstrates that the proposed continuous NTSM controller can drive the system output to the desired reference signal in a finite time in the presence of mismatched time-varying disturbances and nonsmoothed nonlinearities in each channel. The finite time Lyapunov theory is utilized to ensure finite-time convergence of the closed-loop system. The simulation results validate the effectiveness of the proposed continuous NTSM controller.

Section: Introductionmentioning

confidence: 99%

Continuous nonsingular terminal sliding mode control for nonlinear systems subject to mismatched terms

Zhang

Yang

2020

“…It is often effective to use multiple motors/valves to drive a single actuator in mechanical equipment, yielding a higher payload or higher efficiency. If these motors/ valves are the same and work synchronously, it is usually called synchronous control [23], otherwise called harmonic control. Although higher work capacity can be provided by synchronous/harmonic control, there are also drawbacks, for example, decreased precision of motion, large internal forces, and deformation of the mechanical structure.…”

Section: Synchronous Control and Harmonic Controlmentioning

confidence: 99%

Harmonic control of a dual‐valve hydraulic servo system with dynamically allocated flows

Xue

Chen

et al. 2022

Modern industries face increasing demands to improve the precision and workability of equipment, leading to stringent requirements for hydraulic servo systems in terms of flow, accuracy, and output power. High‐flow servo valves and multi‐valve synchronous control methods have seen more applications in the industry to meet these demands. However, high‐flow servo valves are expensive and have unsatisfactory performance, and synchronous control methods require servo valves to have the same hydraulic characteristics, resulting in higher cost and lower accuracy of high‐flow hydraulic servo systems. Also, very little has been conducted on controlling single actuators using multiple valves. In this study, we design a novel dual‐valve hydraulic servo system structure with a high‐flow proportional directional valve that is connected in parallel with a low‐flow servo valve and further develop the mathematical model of this dual‐valve system. Next, a harmonic control scheme was proposed, which included a flow allocation layer and trajectory tracking layer. Thereby, we achieved optimal control of two valves, and robust performance was guaranteed. Finally, we investigate the relationships between the flows of two valves, the deadband of the proportional directional valve, and trajectory tracking errors. Experimental results show that the proposed control scheme can effectively adjust the output flow of each valve dynamically according to the tracking trajectory and the hydraulic characteristics of the two valves, and the tracking performance of the servo system is significantly improved. This method is promised to enable the realization of an economical, high‐flow, high‐precision hydraulic servo system that can be generally used in various fields, such as marine engineering and construction.

“…When machining on a high‐precision positioning platform, the presence of friction causes the system, with a large tracking error, to vibrate. The classical friction model is defined in 8,20,21 and includes static, Coulomb, viscous, breakaway, and Stribeck effect friction. It is a discontinuous friction model with two exponential functions of relative speed.…”

Section: Preliminariesmentioning

confidence: 99%

Virtual feed drive system of machine tools development and applications in diagnosis and servo‐tuning

Lee

2020

This paper proposes a servo-tuning system for five-axis machine tools using a virtual feed drive system. The feed drive systems were first modeled to include the influence of friction and backlash. The particle swarm optimization (PSO) algorithm was adopted to identify and estimate the optimal system parameters. Therefore, the virtual system can be used to comprehend the influence of servo parameters on machining performance. The proposed approach was verified using the QC20-W wireless ballbar to measure the results of the circular test. The experimental results indicate that our proposed approach can improve the rounding error by 21% and mismatch between the feed axes by 16%. In addition, based on parameter variations, such as variations in bandwidth, resonance frequency, and contour error, we propose methods to diagnose online contouring errors.