Faster Positioning of One Degree-of-Freedom Mechanical Systems With Friction and Actuator Saturation

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Chunhong Zheng ◽  
Yuxin Su ◽  
Paolo Mercorelli
Keyword(s):  
Actuator Saturation ◽  
Direct Method ◽  
Mechanical Systems ◽  
Nonlinear Function ◽  
Degree Of Freedom ◽  
Friction Compensation ◽  
Control Law ◽  
Pd Control ◽  
Improved Performance ◽  
Bounded Input

This paper concerns with faster positioning of one degree-of-freedom (1DOF) mechanical systems with friction and actuator saturation. A very simple but quite effective saturated relay proportional-derivative (PD) control is proposed. The proposed control is conceived within the framework of nonlinear PD methodology. It is accomplished by adding a relay position error for friction compensation to the saturated PD control law. For faster transient with bounded input, a saturated nonlinear function is introduced. Lyapunov's direct method is employed to prove global asymptotic positioning. The appealing advantages of the proposed control are that it is fairly easy to construct without involvement of any modeling parameter and has the ability to avoid the actuator saturation. Numerical example and experiments demonstrate the effectiveness and improved performance of the proposed approach.

Exponential Stabilization of a Transversely Vibrating Beam by Boundary Control Via Lyapunov’s Direct Method

1999 ◽  
Vol 123 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Mehrdad P. Fard ◽  
Svein I. Sagatun
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Boundary Control ◽  
Direct Method ◽  
Nonlinear Partial Differential Equation ◽  
Nonlinear Function ◽  
Control Law ◽  
Boundary Stabilization ◽  
Free Transverse Vibration ◽  
Nonlinear Control Law

This paper discusses the boundary stabilization of a beam in free transverse vibration. The dynamics of the beam is presented by a nonlinear partial differential equation (PDE). Based on this model a nonlinear control law is constructed to stabilize the system. The control law is a nonlinear function of the slopes and velocity at the boundary of the beam. The novelty of this article is that it has been possible to exponentially stabilize a free transversely vibrating beam via boundary control without restoring to truncation of the model. This result is achieved while the coupling between longitudinal and transversal displacements has been taken into account.

A Repetitive Learning Method Based on Sliding Mode for Robot Control With Actuator Saturation

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Huihui Tian ◽  
Yuxin Su
Keyword(s):  
Control Method ◽  
Actuator Saturation ◽  
Sliding Mode ◽  
Direct Method ◽  
Actuator Failure ◽  
Asymptotic Tracking ◽  
Repetitive Learning ◽  
Precision Tracking ◽  
Improved Performance ◽  
Three Degree Of Freedom

This paper proposes a sliding mode based repetitive learning control method for high-precision tracking of robot manipulators with actuator saturation. Advantages of the proposed control include the absence of model parameter in the control law formulation and the ability to remove the possibility of actuator failure due to excessive torque input levels. Lyapunov's direct method is employed to prove semiglobal asymptotic tracking. Simulation results on a three degree-of-freedom (3DOF) robot illustrate the effectiveness and improved performance of the proposed scheme.

Single Robust Proportional-Derivative Control for Friction Compensation in Fast and Precise Motion Systems With Actuator Constraint

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Chunhong Zheng ◽  
Yuxin Su ◽  
Paolo Mercorelli
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Direct Method ◽  
Friction Compensation ◽  
Free Solution ◽  
Saturated Control ◽  
Model Free ◽  
Improved Performance ◽  
Experimental Validations ◽  
Control Methodology

Abstract This paper revisits the problem of global asymptotic positioning of uncertain motion systems subject to actuator constraint and friction. A simple model-free saturated control is proposed by incorporating a relay term driven by position error into proportional-derivative (PD) methodology. Lyapunov's direct method is employed to prove global asymptotic positioning stability. The appealing advantages of the proposed approach are that it is conceived within the framework of saturated PD (SPD) control methodology with intuitive structure and absence of modeling parameter and embeds the whole control action within a single saturation function. Benefitted from these advantages, the proposed approach omits the complicated discrimination of the terms that shall be bounded in several saturation functions of the commonly used design and permits easy implementation with an improved performance. An additive feature is that the proposed control has the ability to ensure that the actuator constraint is not breached and assures global asymptotic positioning stability in the presence of unknown friction. Numerical simulations and experimental validations demonstrate the effectiveness and improved performance of the proposed approach. The proposed approach provides a model-free solution for fast transient and high-precision steady-state positioning of uncertain motion systems subject to unknown friction and actuator constraint.

Enhanced Composite Nonlinear Control Technique using Adaptive Control for Nonlinear Delayed Systems

2020 ◽  
Vol 13 (3) ◽  
pp. 396-404
Author(s):  
Sonal Singh ◽  
Shubhi Purwar
Keyword(s):  
Adaptive Control ◽  
Actuator Saturation ◽  
Input Saturation ◽  
Chemical Reactor ◽  
Control Technique ◽  
Control Law ◽  
Nonlinear Feedback ◽  
Composite Nonlinear Feedback ◽  
Delayed Systems ◽  
Analysis Of Stability

Background and Introduction: The proposed control law is designed to provide fast reference tracking with minimal overshoot and to minimize the effect of unknown nonlinearities and external disturbances. Methods: In this work, an enhanced composite nonlinear feedback technique using adaptive control is developed for a nonlinear delayed system subjected to input saturation and exogenous disturbances. It ensures that the plant response is not affected by adverse effect of actuator saturation, unknown time delay and unknown nonlinearities/ disturbances. The analysis of stability is done by Lyapunov-Krasovskii functional that guarantees asymptotical stability. Results: The proposed control law is validated by its implementation on exothermic chemical reactor. MATLAB figures are provided to compare the results. Conclusion: The simulation results of the proposed controller are compared with the conventional composite nonlinear feedback control which illustrates the efficiency of the proposed controller.

A Design Method of LS-SVM Based Stable Adaptive Controller for a Class of Nonlinear Systems

2011 ◽  
Vol 48-49 ◽  
pp. 17-20
Author(s):  
Chun Li Xie ◽  
Tao Zhang ◽  
Dan Dan Zhao ◽  
Cheng Shao
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Nonlinear Function ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Control Law ◽  
Continuous Systems ◽  
Control Schemes ◽  
Closed Systems ◽  
Simulation Results

A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

A Method for Identifying Parameters of Mechanical Joints

1990 ◽  
Vol 57 (2) ◽  
pp. 337-342 ◽  
Author(s):  
J. Wang ◽  
P. Sas
Keyword(s):  
Physical Parameter ◽  
Mechanical Systems ◽  
Degree Of Freedom ◽  
Modal Testing ◽  
Physical Parameters ◽  
Mechanical Joints ◽  
Joint Parameters

A method for identifying the physical parameters of joints in mechanical systems is presented. In the method, a multi-d.o.f. (degree-of-freedom) system is transformed into several single d.o.f. systems using selected eigenvectors. With the result from modal testing, each single d.o.f. system is used to solve for a pair of unknown physical parameters. For complicated cases where the exact eigenvector cannot be obtained, it will be proven that a particular physical parameter has a stationary value in the neighborhood of an eigenvector. Therefore, a good approximation for a joint physical parameter can be obtained by using an approximate eigenvector and the exact value for the joint parameters can be reached by carrying out this process in an iterative way.

4-Degree-of-freedom anti-windup scheme for plants with actuator saturation

2016 ◽  
Vol 47 ◽  
pp. 111-120 ◽  
Author(s):  
Zhong-Shen Li ◽  
Xiao-Qin Mo ◽  
Shang-Jia Guo ◽  
Wei-Yao Lan ◽  
Chun-Qing Huang
Keyword(s):  
Actuator Saturation ◽  
Degree Of Freedom

Active control of flexible one-link manipulators using wavelet networks

Robotica ◽  
2013 ◽  
Vol 31 (8) ◽  
pp. 1275-1283 ◽  
Author(s):  
V. I. Gervini ◽  
E. M. Hemerly ◽  
S. C. P. Gomes
Keyword(s):  
Dead Zone ◽  
Flexible Manipulator ◽  
Friction Compensation ◽  
Control Law ◽  
Wavelet Network ◽  
Stick Slip ◽  
Control Laws ◽  
Operational Conditions ◽  
Structure Control ◽  
Wavelet Networks

SUMMARYThe design of control laws for flexible manipulators is known to be a challenging problem, when using a conventional actuator, i.e., a motor with gear. This is due to the friction of the nonlinear actuator, which causes torque dead zone and stick-slip behavior, thereby hampering the good performance of the control system. The torque needed to attenuate the vibrations, although calculated by the control law, is consumed by the friction inside the actuator, rendering it ineffective to the flexible structure control. Nonlinear friction varies with different operational conditions of the actuator and a friction compensation mechanism based on these models cannot always keep a good performance. This study proposes a new control strategy using wavelet network to friction compensation. Experimental results obtained with a flexible manipulator attest to the good performance of the proposed control law.

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