High Performance Adaptive Control of Mechanical Servo System With LuGre Friction Model: Identification and Compensation

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Xingjian Wang ◽  
Shaoping Wang
Keyword(s):  
Adaptive Control ◽  
Parameter Identification ◽  
Control Algorithm ◽  
Servo System ◽  
Friction Model ◽  
Friction Compensation ◽  
Lugre Friction Model ◽  
Identification Technique ◽  
Lugre Friction ◽  
Adaptive Control Algorithm

LuGre dynamic friction model has been widely used in servo system for friction compensation, but it increases the difficulty of controller design because its parameters are difficult to be identified and its internal state is immeasurable. This paper presents a parameter identification technique based on novel evolutionary algorithm (NEA) for LuGre friction model. In order to settle the practical digital implementation problem of LuGre model, this paper also proposes a modified dual-observer with discontinuous mapping and smooth transfer function. On the basis of the parameter identification results and the modified dual-observer, this paper designs an adaptive control algorithm with dynamic friction compensation for hydraulic servo system. The comparative experiments indicate that the proposed parameter identification technique and the adaptive control algorithm with modified dual-observer are effective with high tracking performance.

scholarly journals Study on the Low Velocity Stability of a Prostate Seed Implantation Robot’s Rotatory Joint

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 284 ◽  
Author(s):  
Bing Li ◽  
Yongde Zhang ◽  
Lipeng Yuan ◽  
Xiaolin Xi
Keyword(s):  
Prostate Cancer ◽  
Parameter Identification ◽  
Control Method ◽  
Friction Model ◽  
Friction Torque ◽  
Low Velocity ◽  
Seed Implantation ◽  
Compensation Control ◽  
Lugre Friction Model ◽  
Lugre Friction

Prostate cancer has one of the highest incidences of male malignant tumors worldwide. Its treatment involves the robotic implantation of radioactive seeds in the perineum, a safe and effective procedure for early, low-risk prostate cancer. In order to ensure precise positioning, the seed implantation needle is set at low terminal velocity. In this paper, the motion output position instability caused by the friction torque of the robot’s motor and rotating joint during low velocity motion was analyzed and studied. This paper also presents a compensation control method based on the LuGre friction model, which offers piecewise parameter identification with GA-PSO. First, based on an analysis of its structure and working principle, the friction torque model of the robotic system and the torque model of the driving motor are established, and the influence of friction torque on motion stability analyzed. Then, based on experimental data of the relationship between velocity and friction torque for no-friction compensation, the velocity point of the minimum torque of the rotating joint and the critical Stribeck velocity point were used for segmental parameter identification; cubic spline interpolation was used for segmental fitting. Furthermore, on the basis of the LuGre model identification method, parameter identification of the genetic algorithm-particle swarm optimization, and compensation control of the LuGre friction model, a control method is analysed and set forth. Malab2017a/Simulink simulation software was used to simulate and analyze the control method, and verify its feasibility. Finally, the cantilever prostate seed implantation robot system was tested to verify the effectiveness of the segmented identification method and the compensation control strategy. The results reveal that motion output position stability at low velocity meets the requirements of the cantilever prostate seed implantation robot, thus providing a vital reference for further research.

scholarly journals Research on Adaptive Friction Compensation of Digital Hydraulic Cylinder Based on LuGre Friction Model

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shouling Jiang ◽  
Kun Zhang ◽  
Hui Wang ◽  
Donghu Zhong ◽  
Jinpeng Su ◽  
...  
Keyword(s):  
Control Method ◽  
Dead Zone ◽  
Hydraulic Cylinder ◽  
Friction Model ◽  
Friction Compensation ◽  
State Variables ◽  
Lugre Friction Model ◽  
Overall Performance ◽  
Lugre Friction ◽  
Adaptive Ability

This paper aims to eliminate nonlinear friction from the performance of the digital hydraulic cylinder to enable it to have good adaptive ability. First, a mathematical model of a digital hydraulic cylinder based on the LuGre friction model was established, and then a dual-observer structure was designed to estimate the unobservable state variables in the friction model. The Lyapunov method is used to prove the global asymptotic stability of the closed-loop system using the adaptive friction compensation method. Finally, Simulink is used to simulate the system performance. The simulation results indicate that the addition of adaptive friction compensation control can effectively reduce system static error, suppress system limit loop oscillation, “position decapitation,” “speed dead zone,” and low-speed creep phenomena, and improve the overall performance of the digital hydraulic cylinder. The control method has practical application value for improving the performance index of the digital hydraulic cylinder.

Identification of Wear Coefficient in Archard Model Based on LuGre Friction Model

2011 ◽  
Vol 343-344 ◽  
pp. 28-32
Author(s):  
Xu Zeng ◽  
Shu Guang Zuo ◽  
Xu Dong Wu
Keyword(s):  
Parameter Identification ◽  
Dynamic Model ◽  
Friction Model ◽  
Road Surface ◽  
Computational Method ◽  
Wear Coefficient ◽  
Experiment Data ◽  
Lugre Friction Model ◽  
Tire Wear ◽  
Lugre Friction

Considering the mechanism interaction between the tire tread and road surface, a dynamic model is established based on LuGre friction model in this paper. The parameter identification of wear coefficient in Archard model is proceeded by simulation in accordance with the experiment data in the correlative references based on the computational method of abrasion loss in Archard model. The results show that this model can fit the experiment data well, provide a theoretic instruction to fulfill the tire wear prediction and lay the foundation of further research in this field.

Lyapunov Based Adaptive Control Method for Hydraulic Servo Drive

2016 ◽  
Author(s):  
Hamid Roozbahani ◽  
Konstantin Frumkin ◽  
Heikki Handroos
Keyword(s):  
Adaptive Control ◽  
Control Algorithm ◽  
Environmental Changes ◽  
Control Method ◽  
Servo System ◽  
Adaptive Controller ◽  
Servo Drive ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
Adaptive Control Algorithm

Adaptive control systems are one of the most significant research directions of modern control theory. It is well known that every mechanical appliance’s behavior noticeably depends on environmental changes, functioning-mode parameter changes and changes in technical characteristics of internal functional devices. An adaptive controller involved in control process allows reducing an influence of such changes. In spite of this such type of control methods is applied seldom due to specifics of a controller designing. The work presented in this paper shows the design process of the adaptive controller built by Lyapunov’s function method for a hydraulic servo system. The modeling of the hydraulic servo system were conducting with MATLAB® software including Simulink® and Symbolic Math Toolbox™. In this study, the Jacobi matrix linearization of the object’s mathematical model and derivation of the suitable reference models based on Newton’s characteristic polynomial were applied. In addition, an intelligent adaptive control algorithm and system model including its nonlinearities was developed to solve Lyapunov’s equation. Developed algorithm works properly and considered plant is met requirement of functioning with. The results shows that the developed adaptive control algorithm increases system performance in use devices significantly and might be used for correction of system’s behavior and dynamics.

Adaptive Trajectory Control and Dynamic Friction Compensation for a Flexible-Link Robot

2010 ◽  
Vol 26 (2) ◽  
pp. 205-217 ◽  
Author(s):  
Vahid Erfanian ◽  
Mansour Kabganian
Keyword(s):  
Internal State ◽  
Friction Model ◽  
Distributed Parameter ◽  
Friction Compensation ◽  
Flexible Link ◽  
Lugre Friction Model ◽  
Control Schemes ◽  
Vibration Attenuation ◽  
Different Types ◽  
Lugre Friction

AbstractFriction compensation techniques are studied for control of a flexible-link robot based on the LuGre friction model. To overcome the problem of uncertain parameters in the friction model, adaptive control schemes are used for two different types of parametric uncertainties. A novel dual-observer technique is proposed to estimate the internal state inside the friction model. A distributed-parameter dynamic model is used for the flexible arm to design the controllers. The Lyapunov stability theorem is used to guarantee the global asymptotic stability of the controllers. The performance of position tracking and link vibration attenuation is verified through experimental results. The results also confirm the effectiveness of the proposed friction compensation schemes.

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