scholarly journals Robust Nonlinear Control Scheme for Electro-Hydraulic Force Tracking Control with Time-Varying Output Constraint

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2074
Author(s):  
Wanshun Zang ◽  
Qiang Zhang ◽  
Jinpeng Su ◽  
Long Feng
Keyword(s):  
Nonlinear Control ◽  
Time Varying ◽  
Parameter Uncertainties ◽  
Structural Vibrations ◽  
Robust Controller ◽  
External Disturbances ◽  
Robust Nonlinear Control ◽  
Hydraulic Force ◽  
Control Scheme ◽  
Output Constraint

This paper presents a robust nonlinear control scheme with time-varying output constraint for the electro-hydraulic force control system (EHFCS). Two typical double-rod symmetrical hydraulic cylinders are employed to simulate force environments in the EHFCS. Therefore, in order to improve the performance of the EHFCS, firstly, the model of the EHFCS is established with taking external disturbances, parameter uncertainties as well as structural vibrations into consideration. Secondly, in order to estimate external disturbances, parameter uncertainties and structural vibrations in the EHFCS and compensate them in the following robust controller design, two disturbance observers (DOs) are designed according to the nonlinear system model. Thirdly, with two estimation values from two DOs, a time-varying constraint-based robust controller (TVCRC) is presented in detail. Moreover, the stability of the proposed controller is analyzed by defining a proper Lyapunov functions. Finally, in order to validate the performance of the proposed controller, a series of simulation studies are conducted using the MATLAB/Simulink software. These simulation results give a fine proof of the efficiency of the proposed controller. What’s more, an experimental setup of the EHFCS is established to further validate the performance. Comparative experimental results show that the proposed controller exhibits better performance than the TVCRC without two DOs and a conventional proportional integral (PI) controller.

A Robust Nonlinear Control Scheme for a Sag Compensator Active Multilevel Rectifier Without Sag Detection Algorithm

2012 ◽  
Vol 27 (8) ◽  
pp. 3576-3583 ◽  
Author(s):  
Jesus Lira ◽  
Nancy Visairo ◽  
Ciro Nunez ◽  
Adrian Ramirez ◽  
Hebertt Sira-Ramirez
Keyword(s):  
Nonlinear Control ◽  
Detection Algorithm ◽  
Robust Nonlinear Control ◽  
Control Scheme

Operator-Based Robust Nonlinear Control Design of a Robot Arm with Micro-Hand

2016 ◽  
Vol 28 (4) ◽  
pp. 568-578 ◽  
Author(s):  
Zhengxiang Ma ◽  
◽  
Aihui Wang ◽  
Tiejun Chen ◽  
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Nonlinear Control ◽  
Angular Position ◽  
Control Design ◽  
Robot Arm ◽  
Robust Nonlinear Control ◽  
Precise Position ◽  
Control Scheme ◽  
Loop Feedback

[abstFig src='/00280004/14.jpg' width='300' text='Robot arm with micro-hand system' ] This work focuses on a robust nonlinear control design of a robot arm with micro-hand (RAMH) by using operator-based robust right coprime factorization (RRCF) approach. In the proposed control system, we can control the endpoint position of robot arm and obtain the desired force of micro-hand to perform a task, and a miniature pneumatic curling soft (MPCS) actuator which can generate bidirectional curling motions in different positive and negative pressures is used to develop the fingers of micro-hand. In detail, to control successively the precise position of robot arm and the desired force of three fingers according to the external environment or task involved, this paper proposes a double-loop feedback control architecture using operator-based RRCF approach. First, the inner-loop feedback control scheme is designed to control the angular position of the robot arm, the operator controllers and the tracking controller are designed, and the robust stability and tracking conditions are derived. Second, the complex stable inner-loop and micro-hand with three fingers are viewed as two right factorizations separately, a robust control scheme using operator-based RRCF approach is presented to control the fingers forces, and the robust tracking conditions are also discussed. Finally, the effectiveness of the proposed control system is verified by experimental and simulation results.

Emulating time varying nonlinear uncertainties and disturbances in linear time invariant systems

SIMULATION ◽  
2012 ◽  
Vol 88 (12) ◽  
pp. 1499-1507 ◽  
Author(s):  
Y Horen ◽  
A Kuperman ◽  
Z Vainer ◽  
S Tapuchi ◽  
M Averbukh
Keyword(s):  
Linear Time ◽  
Time Varying ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Nominal System ◽  
Linear Time Invariant ◽  
Nonlinear Uncertainties ◽  
System Output ◽  
Actual Field ◽  
Linear Time Invariant Systems

An approach allowing the creation of parameter uncertainties and external disturbances without any hardware parts supplementary to the nominal system is proposed in this manuscript. The emulating signal, reflecting the plant variations, essential for testing of controllers, is created in software and added to the plant input, forcing the nominal system output to resemble the output of a system with actual uncertainties and disturbances, thus allowing us to test the controller’s robustness prior to an actual field test. In addition, the full state vector of the emulated system may be reconstructed and fed back to the controller, if necessary. The proposed methods allow simultaneous emulation of any combination of time-varying parameter variations and external disturbances. The method can be related to a class of enhanced hardware-in-the-loop simulations, since the nominal hardware is present in the setup in addition to the controller under test. The proposed techniques can be used to test the performance of advanced control algorithms before their mass production. Extended simulation results are reported to confirm the feasibility of the proposed approaches.

Asymptotic stabilization of a class of uncertain nonlinear time-delay fractional-order systems via a robust delay-independent controller

2017 ◽  
Vol 24 (19) ◽  
pp. 4541-4550 ◽  
Author(s):  
T. Binazadeh ◽  
M. Yousefi
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Sliding Mode ◽  
Robust Stabilization ◽  
Delay Systems ◽  
Time Varying ◽  
State Variables ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Sliding Manifold

This paper studies the robust stabilization for a class of nonlinear time-delay fractional order (FO) systems in the presence of some practical aspects. The considered aspects in the FO system include: nonlinear Lipschitz functions; time-varying norm-bounded uncertain terms; and time-delays in the state variables. A major challenge in the control of time-delay systems is that the value of delay is usually not perfectly known or it may be even time-varying. In this paper, a novel asymptotic stabilizing control law is proposed which is delay independent and also has a robust manner in the presence of uncertain terms in the model which may be due to model uncertainties (parameter uncertainties or model simplification) and/or external disturbances. The proposed controller is a FO sliding mode controller that is designed such that the closed-loop system is asymptotically delay-independent stable. For this purpose, a FO sliding manifold is introduced and the occurrence of the reaching phase in a finite time is proved. Finally, in order to validate the theoretical results, an example is given and simulation results confirm the appropriate performance of the proposed controller.

scholarly journals Investigation into the Dynamics and Control of an Underwater Vehicle-Manipulator System

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Mohan Santhakumar
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Dynamic Coupling ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Model Reference Control ◽  
Control Scheme ◽  
Underwater Manipulator ◽  
Dynamics And Control ◽  
And Control

This study addresses the detailed modeling and simulation of the dynamic coupling between an underwater vehicle and manipulator system. The dynamic coupling effects due to damping, restoring, and inertial effects of an underwater manipulator mounted on an autonomous underwater vehicle (AUV) are analyzed by considering the actuator and sensor characteristics. A model reference control (MRC) scheme is proposed for the underwater vehicle-manipulator system (UVMS). The effectiveness of the proposed control scheme is demonstrated using numerical simulations along with comparative study between conventional proportional-integral-derivative (PID) control. The robustness of the proposed control scheme is also illustrated in the presence of external disturbances and parameter uncertainties.

scholarly journals Robust attitude tracking control scheme for a multi-body spacecraft using a radial basis function network and terminal sliding mode

2014 ◽  
Vol 24 (5) ◽  
Author(s):  
CHANGQING YUAN ◽  
YANHUA ZHONG ◽  
JINGRUI ZHANG ◽  
HONGBUO LI ◽  
GUOJUN YANG ◽  
...  
Keyword(s):  
Basis Function ◽  
Sliding Mode ◽  
Radial Basis Function Network ◽  
Robust Controller ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Multi Body ◽  
Function Network

We present a novel robust control scheme that deals with multi-body spacecraft attitude tracking problems. The control scheme consists of a radial basis function network (RBFN) and a robust controller. By using the finite time convergence property of the terminal sliding mode (TSM), we derive a new online learning algorithm for updating all the parameters of the RBFN that ensures the RBFN has fast approximation for the parameter uncertainties and external disturbances. We design a robust controller to compensate RBFN approximation errors and realise the anticipative stability and performance properties. We can also achieve closed-loop system stability using Lyapunov stability theory.No detailed knowledge of the non-linear dynamics of the spacecraft is required at any point in the entire design process, and the proposed robust scheme is simple and effective and can be applied to more complex systems. Simulation results demonstrate the good tracking characteristics of the proposed control scheme in the presence of inertial uncertainties and external disturbances.

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