scholarly journals Coordination of Multiple Robotic Vehicles in Obstacle-Cluttered Environments

Robotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 75
Author(s):  
Charalampos P. Bechlioulis ◽  
Panagiotis Vlantis ◽  
Kostas J. Kyriakopoulos
Keyword(s):  
Information Exchange ◽  
Control Method ◽  
Field Of View ◽  
Line Of Sight ◽  
Control Law ◽  
Performance Control ◽  
Cluttered Environments ◽  
Prescribed Performance Control ◽  
Control Scheme ◽  
Connectivity Maintenance

In this work, we consider the motion control problem for a platoon of unicycle robots operating within an obstacle-cluttered workspace. Each robot is equipped with a proximity sensor that allows it to perceive nearby obstacles as well as a camera to obtain its relative position with respect to its preceding robot. Additionally, no robot other than the leader of the team is able to localize itself within the workspace and no centralized communication network exists, i.e., explicit information exchange between the agents is unavailable. To tackle this problem, we adopt a leader–follower architecture and propose a novel, decentralized control law for each robot-follower, based on the Prescribed Performance Control method, which guarantees collision-free tracking and visual connectivity maintenance by ensuring that each follower maintains its predecessor within its camera field of view while keeping static obstacles out of the line of sight for all time. Finally, we verify the efficacy of the proposed control scheme through extensive simulations.

scholarly journals Fuzzy-approximation-based prescribed performance control of air-breathing hypersonic vehicles with input constraints

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987735
Author(s):  
Xingge Li ◽  
Gang Li ◽  
Yan Zhao ◽  
Xuchao Kang
Keyword(s):  
Control Method ◽  
Hypersonic Vehicle ◽  
Hypersonic Vehicles ◽  
Input Constraints ◽  
Air Breathing ◽  
Performance Control ◽  
Prescribed Performance ◽  
Fuzzy Approximation ◽  
Prescribed Performance Control ◽  
Control Scheme

In this article, aiming at the longitudinal dynamics model of air-breathing hypersonic vehicles, a fuzzy-approximation-based prescribed performance control scheme with input constraints is proposed. First, this article presents a novel prescribed performance function, which does not depend on the sign of initial tracking error. And combining prescribed performance control method with backstepping control, the control scheme can ensure that system can converge at a prescribed rate of convergence, overshoot, and steady-state error. In order to solve the problem that backstepping control method needs to be differentiated multiple times, fuzzy approximators are used to estimate the unknown functions, and norm estimation approach is used to simplify the computation of fuzzy approximator. Aiming at the problem of input saturation of actuator in subsystem of air-breathing hypersonic vehicle, the new auxiliary system is designed to ensure the stability and robustness of air-breathing hypersonic vehicle system under input constraints. Finally, the effectiveness of the proposed control strategy is verified by simulation analysis.

scholarly journals Design of decentralized adaptive control approach for large-scale nonlinear systems subjected to input delays under prescribed performance

2021 ◽  
Author(s):  
Yu-Qun Han
Keyword(s):  
Adaptive Control ◽  
Nonlinear Systems ◽  
Large Scale ◽  
Control Method ◽  
Performance Control ◽  
Prescribed Performance ◽  
Control Approach ◽  
Prescribed Performance Control ◽  
Control Scheme ◽  
Input Delays

Abstract For the first time, the issue of input delays and prescribed performance control is investigated in the same framework for large-scale nonlinear systems in this study, and a original adaptive decentralized control method is proposed take advantage of multi-dimensional Taylor network (MTN) method. Firstly, the problem of input delays is solved by introducing new variables, and a new form of coordinate transformation is introduced before controller design, which simplified the control system. Secondly, the problem of prescribed performance control is coped with by integrating the idea of prescribed performance into the Lyapunov functions of first step of backstepping of each subsystem. Thirdly, MTNs are employed to evaluate the combination of unknown functions, and then a decentralized MTN-based adaptive control scheme is developed by way of backstepping technology. The theoretical analysis indicates that the proposed control scheme can implement the expected tracking goals under the condition of meeting the prescribed performance control. Finally, one numerical example is given to show the validity and rationality of the proposed control method.

scholarly journals Disturbance compensation-based output feedback adaptive control for shape memory alloy actuator system

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142199399
Author(s):  
Xiaoguang Li ◽  
Bi Zhang ◽  
Daohui Zhang ◽  
Xingang Zhao ◽  
Jianda Han
Keyword(s):  
Adaptive Control ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Control Method ◽  
Control Law ◽  
Reference Trajectory ◽  
Disturbance Compensation ◽  
Comparison Results ◽  
Control Scheme ◽  
Actuator System

Shape memory alloy (SMA) has been utilized as the material of smart actuators due to the miniaturization and lightweight. However, the nonlinearity and hysteresis of SMA material seriously affect the precise control. In this article, a novel disturbance compensation-based adaptive control scheme is developed to improve the control performance of SMA actuator system. Firstly, the nominal model is constructed based on the physical process. Next, an estimator is developed to online update not only the unmeasured system states but also the total disturbance. Then, the novel adaptive controller, which is composed of the nominal control law and the compensation control law, is designed. Finally, the proposed scheme is evaluated in the SMA experimental setup. The comparison results have demonstrated that the proposed control method can track reference trajectory accurately, reject load variations and stochastic disturbances timely, and exhibit satisfactory robust stability. The proposed control scheme is system independent and has some potential in other types of SMA-actuated systems.

scholarly journals Robust Adaptive Neural Control of Morphing Aircraft with Prescribed Performance

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Zhonghua Wu ◽  
Jingchao Lu ◽  
Jingping Shi ◽  
Yang Liu ◽  
Qing Zhou
Keyword(s):  
Neural Control ◽  
Switching Function ◽  
Parameter Uncertainties ◽  
Adaptive Neural Control ◽  
Remarkable Feature ◽  
Performance Control ◽  
Prescribed Performance ◽  
Prescribed Performance Control ◽  
Control Scheme ◽  
Smooth Switching

This study proposes a low-computational composite adaptive neural control scheme for the longitudinal dynamics of a swept-back wing aircraft subject to parameter uncertainties. To efficiently release the constraint often existing in conventional neural designs, whose closed-loop stability analysis always necessitates that neural networks (NNs) be confined in the active regions, a smooth switching function is presented to conquer this issue. By integrating minimal learning parameter (MLP) technique, prescribed performance control, and a kind of smooth switching strategy into back-stepping design, a new composite switching adaptive neural prescribed performance control scheme is proposed and a new type of adaptive laws is constructed for the altitude subsystem. Compared with previous neural control scheme for flight vehicle, the remarkable feature is that the proposed controller not only achieves the prescribed performance including transient and steady property but also addresses the constraint on NN. Two comparative simulations are presented to verify the effectiveness of the proposed controller.

scholarly journals Prescribed Performance Control with Sliding-Mode Dynamic Surface for a Glue Pump Motor Based on Extended State Observers

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 282
Author(s):  
Peiyu Wang ◽  
Liangkuan Zhu ◽  
Chunrui Zhang ◽  
Chengcheng Wang ◽  
Kangming Xiao
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Dynamic Surface Control ◽  
Extended State ◽  
Dynamic Surface ◽  
Performance Control ◽  
Prescribed Performance ◽  
Compound Control ◽  
Prescribed Performance Control ◽  
State Observers

The actuator of a particleboard glue-dosing system, the glue pump motor, is affected by external disturbances and unknown uncertainty. In order to achieve accurate glue-flow tracking, in this paper, a glue pump motor compound control method was designed. First, the prescribed performance control method is used to improve the transient behaviors, and the error of the glue flow tracking is guaranteed to converge to a preset range, as a result of the design of an appropriate performance function. Second, two extended state observers were designed to estimate the state vector and the disturbance, in order to improve the robustness of the controlled system. To further strengthen the steady-state performance of the system, the sliding-mode dynamic surface control method was introduced to compensate for uncertainties and disturbances. Finally, a Lyapunov stability analysis was conducted, in order to prove that all of the signals are bounded in a closed-loop system, and the effectiveness and feasibility of the proposed method were verified through numerical simulation.

A novel guaranteed tracking performance control for reentry vehicle with actuator constraints and uncertainties

2019 ◽  
Vol 41 (13) ◽  
pp. 3787-3798 ◽  
Author(s):  
Zhenxin Feng ◽  
Jianguo Guo ◽  
Jun Zhou
Keyword(s):  
Actuator Saturation ◽  
Tracking Performance ◽  
Control Law ◽  
Performance Control ◽  
Reentry Vehicle ◽  
Performance Technique ◽  
Control Scheme ◽  
Enormous Amount ◽  
Actuator Constraints ◽  
Compensation Design

A novel guaranteed tracking performance control scheme is presented for the reentry vehicle encountered in actuator saturation and enormous amount of uncertainties via time-varying barrier Lyapunov function (TVBLF) method. The required stable and transient tracking performance of the reentry attitudes are simultaneously enhanced by the proposed logarithm-type TVBLF and the control design complexity is reduced compared with the prescribed performance technique. Moreover, in order to eliminate the control performance degradation caused by the actuator constraints, an auxiliary error compensation design is inserted into the control law. In addition, the uncertainty rejection capability of the control system is achieved by exploiting the MIMO nonlinear extended disturbance observer. Finally, the uniform ultimately boundedness of the closed-loop system is established and numerical simulations are verified to demonstrate the effectiveness of the proposed control law for the reentry vehicle subject to attitude constraints, actuator saturations and uncertainties.

Sliding-Mode Position Control of PMSLM Based on Grey Forecasting Model

2014 ◽  
Vol 687-691 ◽  
pp. 85-88
Author(s):  
Hua Sun ◽  
Yue Hong Dai ◽  
Chuan Sheng Tang
Keyword(s):  
Control Problem ◽  
Position Control ◽  
Control Method ◽  
Sliding Mode ◽  
Friction Model ◽  
Forecasting Model ◽  
Control Law ◽  
Compensation Control ◽  
Grey Forecasting ◽  
Control Scheme

This paper presented a new method of sliding mode control for position control problem in view of the uncertainty of friction model of permanent magnet synchronous linear motor (PMSLM). This is an estimation compensation control scheme for non-homogeneous sequence data.The stability of the proposed control law was verified according to Lyapunov stable theory.Comparison with traditional control was given through Matlab simulations, which proved the feasibility and efficiency of the proposed control method for PMSLM drive system.

scholarly journals Fuzzy Adaptive Prescribed Performance Control for a Class of Uncertain Nonlinear Systems with Unknown Dead-Zone Inputs

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Xiang ◽  
Ning Li ◽  
Yeguo Sun
Keyword(s):  
Control Method ◽  
Dead Zone ◽  
Constrained System ◽  
Performance Control ◽  
Prescribed Performance ◽  
Performance Technique ◽  
Prescribed Performance Control ◽  
Feedback Control Method ◽  
Unknown Control ◽  
Fuzzy Adaptive

This paper proposes a fuzzy adaptive prescribed performance control scheme for a class of uncertain chaotic systems with unknown control gains and unknown dead-zone inputs. Firstly, an error transformation is introduced to transform the original constrained system into an equivalent unconstrained one. Then, based on the error transformation technique and the predefined performance technique, a fuzzy adaptive feedback control method is developed. It is shown that all the signals of the resulting closed-loop system are bounded. Finally, an illustrative example is given to demonstrate the effectiveness and usefulness of the proposed technique.

scholarly journals Variable Gain Prescribed Performance Control for Dynamic Positioning of Ships with Positioning Error Constraints

2022 ◽  
Vol 10 (1) ◽  
pp. 74
Author(s):  
Chenglong Gong ◽  
Yixin Su ◽  
Danhong Zhang
Keyword(s):  
Closed Loop ◽  
Input Saturation ◽  
Control Law ◽  
Positioning Error ◽  
Performance Bounds ◽  
External Disturbances ◽  
Performance Control ◽  
Prescribed Performance ◽  
Variable Gain ◽  
Prescribed Performance Control

In this paper, a variable gain prescribed performance control law is proposed for dynamic positioning (DP) of ships with positioning error constraints, input saturation and unknown external disturbances. The error performance index functions are designed to preset the prescribed performance bounds and the error mapping functions are constructed to incorporate the prescribed performance bounds into the DP control design. The variable gain technique is used to limit the output amplitude of the control law to avoid input saturation of the system by dynamically adjusting the control gain of the DP control law according to the positioning errors, and the error mapping function replaces the positioning error as a recursive sliding-mode surface to realize the prescribed performance control of the system and guarantee the stability of the closed-loop system with variable control gains. It has been proved that the proposed DP control law can make the uniformly ultimately boundedness of all signals in the DP closed-loop control system. The numerical simulation results illustrate that the proposed control law can make the ship’s position and heading maintain at the desired value with positioning error constraints, enhance the non-fragility of the DP control law to the perturbation of system’s parameters and improve the system’s rejection ability to external disturbances.

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