Yaw-rate-tracking-based Automated Vehicle Path Following: An MRAC Methodology with A Closed-Loop Reference Model

Author(s):  
Xingyu Zhou ◽  
Zejiang Wang ◽  
Heran Shen ◽  
Junmin Wang

Abstract Concerning automated vehicles, various path-following controllers have been designed by the model reference adaptive control (MRAC) approach. Through appropriate Lyapunov redesigns, asymptotical stability and signal boundedness are ensured for the path-tracking control loops. However, transient behaviors of the closed-loop responses are seldom considered in the context of MRAC synthesis. To bridge the foregoing gap, a closed-loop reference model-based MRAC, which yields an improved transient performance compared with a traditional MRAC, is exploited to synthesize a vehicular path following control law. Besides, an infinitely differentiable projection operator is complemented to the control parameters' adaptation schemes for estimation speed-up and robustness enhancement. Hardware-in-the loop experiments are used to evaluate the proposed method and to demonstrate its improvement over some conventional MRAC designs.

Algorithms ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 201
Author(s):  
Hossein Alimohammadi ◽  
Baris Baykant Alagoz ◽  
Aleksei Tepljakov ◽  
Kristina Vassiljeva ◽  
Eduard Petlenkov

Real control systems require robust control performance to deal with unpredictable and altering operating conditions of real-world systems. Improvement of disturbance rejection control performance should be considered as one of the essential control objectives in practical control system design tasks. This study presents a multi-loop Model Reference Adaptive Control (MRAC) scheme that leverages a nonlinear autoregressive neural network with external inputs (NARX) model in as the reference model. Authors observed that the performance of multi-loop MRAC-fractional-order proportional integral derivative (FOPID) control with MIT rule largely depends on the capability of the reference model to represent leading closed-loop dynamics of the experimental ML system. As such, the NARX model is used to represent disturbance-free dynamical behavior of PID control loop. It is remarkable that the obtained reference model is independent of the tuning of other control loops in the control system. The multi-loop MRAC-FOPID control structure detects impacts of disturbance incidents on control performance of the closed-loop FOPID control system and adapts the response of the FOPID control system to reduce the negative effects of the additive input disturbance. This multi-loop control structure deploys two specialized control loops: an inner loop, which is the closed-loop FOPID control system for stability and set-point control, and an outer loop, which involves a NARX reference model and an MIT rule to increase the adaptation ability of the system. Thus, the two-loop MRAC structure allows improvement of disturbance rejection performance without deteriorating precise set-point control and stability characteristics of the FOPID control loop. This is an important benefit of this control structure. To demonstrate disturbance rejection performance improvements of the proposed multi-loop MRAC-FOPID control with NARX model, an experimental study is conducted for disturbance rejection control of magnetic levitation test setup in the laboratory. Simulation and experimental results indicate an improvement of disturbance rejection performance.


2013 ◽  
Vol 437 ◽  
pp. 623-628 ◽  
Author(s):  
Hsin Guan ◽  
Li Zeng Zhang ◽  
Xin Jia

Parameters of the optimal preview acceleration driver model for vehicle directional control are determined by drivers delay/lag time and parameters of the reference model of the controlled vehicle. A moving vehicle is a time-varying and nonlinear system, so it is difficult to obtain accurate parameters of the reference model. If large modeling errors of the reference model occur, the classic driver model cannot ensure the driver/vehicle closed-loop system have a satisfactory performance. In this paper, an improved optimal preview acceleration model with a correction factor was proposed, which is based on sensitivity analysis and MRAC (the model reference adaptive control). Simulation results show that the improved driver model has more satisfactory adaptability and robustness comparing with the classic driver model.


2016 ◽  
Vol 39 (7) ◽  
pp. 987-999 ◽  
Author(s):  
Zewei Zheng ◽  
Keyu Yan ◽  
Shuaixian Yu ◽  
Bing Zhu ◽  
Ming Zhu

This paper proposes two different path following control schemes for a stratospheric airship with actuator saturation. Each of the control schemes consists of a guidance loop and an attitude control loop. In both schemes, guidance laws are designed according to the line-of-sight guidance-based path following principle. In the first control scheme, a robust H∞ controller without constraints is designed based on the planar model of a stratospheric airship to stabilize path-following errors. The input constraints are then addressed by using a regional [Formula: see text]-based model recovery anti-windup compensator, which prevents the unconstrained controller from misbehaving in the constrained closed loop with anti-windup augmentation and ensures the systematic stability. In the second control scheme, model predictive control is applied to guarantee the path-following of the closed-loop system and explicitly address the magnitude and rate of rudders of the stratospheric airship. Theoretical results are illustrated by numerical simulations where both closed-loop systems are capable of following their desired paths and the constraints on control inputs are satisfied.


2014 ◽  
Vol 1006-1007 ◽  
pp. 599-603
Author(s):  
Xing Ji ◽  
Lei Zhang ◽  
Jian Cao ◽  
Shan Ma

A novel path-following control method of under-actuated AUV is proposed in this paper. Under the Serret-Frenet coordinate system, dynamics equations of path-following error were established based on virtual target AUV. And then combined with dynamics equations of AUV, controller was designed based on Lyapunov stability theory and backstepping technique. Simulation results showed that path-following error could converge to zero rapidly by using the proposed non-linear feedback control law, to make the AUV navigate along the referenced path.


2021 ◽  
Author(s):  
Mingzhen Lin ◽  
Zhiqiang Zhang ◽  
Yandong Pang ◽  
Hongsheng Lin ◽  
Qing Ji

Abstract The path following control under disturbance was studied for an underactuated unmanned surface vehicle (USV) subject to the rudder angle and velocity constraints. For this reason, a variable look-ahead integral line-of-sight (LOS) guidance law was designed on the basis of the disturbance estimation and compensation, and a cascade path following control system was created following the heading control law based on the model prediction. Firstly, the guidance law was designed using the USV three-degree-of-freedom (DOF) motion model and the LOS method, while the tracking error state was introduced to design the real-time estimation of disturbance observer and compensate for the influence of ocean current. Moreover, the stability of the system was analyzed. Secondly, sufficient attention was paid to the rudder angle and velocity constraints and the influence of system delay and other factors in the process of path following when the heading control law was designed with the USV motion response model and the model predictive control (MPC). The moving horizon optimization strategy was adopted to achieve better dynamic performance, effectively overcome the influence of model and environmental uncertainties, and further prove the stability of the control law. Thirdly, a simulation experiment was carried out to verify the effectiveness and advancement of the proposed algorithm. Fourthly, the “Sturgeon 03” USV was used in the lake test of the proposed control algorithm to prove its feasibility in the engineering practices.


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