scholarly journals Finite-time Tracking Control with Velocity Constraints for the Stochastic Rehabilitative Training Walker System Considering Different Rehabilitee Masses

2021 ◽  
Author(s):  
Ping Sun ◽  
Shuoyu Wang ◽  
Rui Shan
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Control Method ◽  
Stochastic Dynamic ◽  
Predictive Algorithm ◽  
Tracking Controller ◽  
Nonlinear Tracking ◽  
Simulation And Experiment ◽  
Velocity Constraints ◽  
Velocity Constraint

Abstract This study discusses a finite-time tracking controller for a rehabilitative training walker that imposes velocity constraints. The walker was described using a stochastic model through which the rehabilitee mass can randomly change, and a velocity constraint method was proposed to control the velocity input to every omniwheel based on a model predictive algorithm. This approach is novel in that the velocity constraint information obtained from the kinematics model was used to design the tracking controller based on the stochastic dynamic model, thus successfully constraining the actual velocity of walker as per the stochastic system. The nonlinear tracking controller was built for the stochastic rehabilitative walker to make the system’s finite time stable. Also, simulation and experiment were performed, and results confirmed that the proposed tracking control method with velocity constraints is very effective, so it may enable various rehabilitees to train safely.

Robust finite-time trajectory tracking control for a space manipulator with parametric uncertainties and external disturbances

2021 ◽  
pp. 095441002110147
Author(s):  
Qijia Yao
Keyword(s):  
Trajectory Tracking ◽  
Finite Time ◽  
Tracking Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Parametric Uncertainties ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Space Manipulator ◽  
Tracking Controller

Space manipulator is considered as one of the most promising technologies for future space activities owing to its important role in various on-orbit serving missions. In this study, a robust finite-time tracking control method is proposed for the rapid and accurate trajectory tracking control of an attitude-controlled free-flying space manipulator in the presence of parametric uncertainties and external disturbances. First, a baseline finite-time tracking controller is designed to track the desired position of the space manipulator based on the homogeneous method. Then, a finite-time disturbance observer is designed to accurately estimate the lumped uncertainties. Finally, a robust finite-time tracking controller is developed by integrating the baseline finite-time tracking controller with the finite-time disturbance observer. Rigorous theoretical analysis for the global finite-time stability of the whole closed-loop system is provided. The proposed robust finite-time tracking controller has a relatively simple structure and can guarantee the position and velocity tracking errors converge to zero in finite time even subject to lumped uncertainties. To the best of the authors’ knowledge, there are really limited existing controllers can achieve such excellent performance under the same conditions. Numerical simulations illustrate the effectiveness and superiority of the proposed control method.

A Novel Tracking Controller for Autonomous Underwater Vehicles with Thruster Fault Accommodation

2015 ◽  
Vol 69 (3) ◽  
pp. 593-612 ◽  
Author(s):  
Bing Sun ◽  
Daqi Zhu ◽  
Simon X. Yang
Keyword(s):  
Tracking Control ◽  
Autonomous Underwater Vehicle ◽  
Control Method ◽  
Control Strategies ◽  
Autonomous Underwater Vehicles ◽  
Solution Space ◽  
Robust Tracking Control ◽  
Fault Accommodation ◽  
Tracking Controller ◽  
Pseudo Inverse

In this paper, for the over-actuated Autonomous Underwater Vehicle (AUV) system, a novel tracking controller with thruster fault accommodation is proposed. Firstly, a cascaded control method is proposed for AUV robust tracking control. Then, we deal with the tracking control problem when one or more thrusters are completely or partly malfunctioning. Different control strategies are used to reallocate the thruster forces. For the cases that thrusters are partly malfunctioning, a weighted pseudo-inverse is firstly used to generate the normalised thruster forces. When the normalised thruster forces are out of maximum limits, the Quantum-behaviour Particle Swarm Optimisation (QPSO) is used for the restricted usage of the faulty thruster and to find the solution of the control reallocation problem within the limits. Compared with the weighted pseudo-inverse method, the QPSO algorithm does not need truncation or scaling to ensure the feasibility of the solution due to its particle search in the feasible solution space. The proposed controller is implemented in order to evaluate its performance in different faulty situations and its efficiency is demonstrated through simulation results.

Tracking control in x-y plane of an offshore container crane

2016 ◽  
Vol 23 (3) ◽  
pp. 469-483 ◽  
Author(s):  
Dongho Kim ◽  
Youngjin Park
Keyword(s):  
Tracking Control ◽  
Control Method ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Target Position ◽  
Container Ship ◽  
Scaled Model ◽  
Tracking Controller ◽  
Loading And Unloading ◽  
Linearized Model

A tracking controller is proposed for a crane attached to a mobile harbor (MH) equipped with a dual-stage trolley system, to dynamically position a container from the MH to the container ship or vice versa. Wave-induced motions of the MH and container ship occur during loading and unloading operations owing to external disturbances such as waves. However, a challenging task is to move a payload with unwanted swing motions accurately to the loading and unloading positions on a moving target vessel. To solve this problem, a dynamic MH crane model is derived in three-dimensional space, with roll, pitch, and heave motions caused by sea-wave disturbances. The MH crane model is then linearized to design a tracking controller and the parameters of the linearized model are obtained by carrying out the system identification process. A preview tracking control method that includes feedback and feed-forward control with the predicted target position in the x-y plane in the near future is utilized. Through numerical simulations and experiments with a scaled model, the tracking performance of the proposed dynamic positioning control system is considered when sinusoidal roll and pitch motions of the MH are generated to mimic the wavy sea environment.

Interaction Forces Identification Modeling and Tracking Control for Rehabilitative Training Walker

2019 ◽  
Vol 23 (2) ◽  
pp. 183-195
Author(s):  
Ping Sun ◽  
Wenjiao Zhang ◽  
Shuoyu Wang ◽  
Hongbin Chang ◽  
◽  
...  
Keyword(s):  
Tracking Control ◽  
Control Method ◽  
Tracking Error ◽  
Model Identification ◽  
Fuzzy Model ◽  
Adaptive Backstepping ◽  
Interaction Forces ◽  
Design Procedures ◽  
Tracking Motion ◽  
Simulation And Experiment

In this study, we propose a model and an adaptive backstepping tracking control method for omnidirectional rehabilitative training walker. The aim of the study is to design a stable tracking controller that can guarantee accurate tracking motion of the omnidirectional walker considering the interaction forces of the user and walker. A novel fuzzy model identification method was proposed to describe the interaction forces by using the reduced values of tracking performance. Further, an adaptive backstepping controller was developed to compensate the interaction forces on the basis of the identified model and adapt the change of user’s mass. The asymptotic stability of the trajectory tracking error and the velocity tracking error were guaranteed. As an application, simulation and experiment results were provided to illustrate the effectiveness of the proposed design procedures.

Aeroengine Multivariable Nonlinear Tracking Control Based on Uncertainty and Disturbance Estimator

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Lingfei Xiao
Keyword(s):  
Tracking Control ◽  
Control Method ◽  
Reference Model ◽  
Robust Tracking Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Control Approach ◽  
Nonlinear Tracking ◽  
Uncertainty And Disturbance Estimator ◽  
Disturbance Estimator

The multivariable robust tracking control problem for aeroengine is considered in this paper. On the basis of the aeroengine nonlinear affine uncertain dynamic model, and according to uncertainty and disturbance estimator (UDE) control approach, a novel aeroengine multivariable robust nonlinear tracking control method is presented in order to provide favorable tracking and disturbance rejection performance. After getting a generalization form of UDE-based aeroengine multivariable controller, a simplification form of control law is obtained when a specified form of low-pass filter is applied. Reference model of the aeroengine system should have satisfying dynamic, thus an optional reference model is provided. Simulation on a twin-shaft aeroengine with two inputs, verifies the effectiveness of the proposed method.

scholarly journals Flatness-Based Aggressive Formation Tracking Control of Quadrotors with Finite-Time Estimated Feedforwards

2021 ◽  
Vol 11 (2) ◽  
pp. 792
Author(s):  
Zhicheng Hou ◽  
Gong Zhang ◽  
Wenlin Yang ◽  
Weijun Wang ◽  
Changsoo Han
Keyword(s):  
Motion Control ◽  
Finite Time ◽  
Attitude Control ◽  
Tracking Control ◽  
Controller Design ◽  
High Order ◽  
Experimental Results ◽  
Formation Tracking ◽  
Tracking Controller ◽  
Formation Pattern

In this paper we address a decentralized neighbor-based formation tracking control of multiple quadrotors with leader–follower structure. Different from most of the existing work, the formation tracking controller is given in one loop without distinguishing the motion control and attitude control by means of the theory of flatness. In order to achieve an aggressive formation tracking, the high-order states of the neighbors motion are estimated by using a proposed extended finite-time observer for each quadrotor. Then the estimated motion states are used as feedforwards in the formation controller design. Simulation and experimental results show that the proposed formation controller improves the formation performance, i.e., the formation pattern of the quadrotors is better maintained than that using the formation controller without high-order feedforwards, when tracking an aggressive reference formation trajectory.

scholarly journals Disturbance Compensation Based Finite-Time Tracking Control of Rigid Manipulator

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Mohamed Elamin Sahabi ◽  
Guipu Li ◽  
Xiangyu Wang ◽  
Shihua Li
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Disturbance Observer ◽  
Control Method ◽  
Disturbance Compensation ◽  
Adding A Power Integrator ◽  
Time Simulation ◽  
Control Scheme ◽  
Mismatched Disturbances ◽  
Power Integrator

The finite-time tracking control problem of rigid manipulator system with mismatched disturbances is investigated via a composite control method. The proposed composite controller is based on finite-time disturbance observer and adding a power integrator technique. First, a finite-time disturbance observer is designed which guarantees that the disturbances can be estimated in a finite time. Then, a composite controller is developed based on adding a power integrator approach and the estimates of the disturbances. Under the proposed composite controller, the manipulator position can track the desired position in a finite time. Simulation results show the effectiveness of the proposed control scheme.

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