scholarly journals A Study on Longitudinal Control Law in order to Improvement of T-50 Fine Tracking Performance

2005 ◽  
Vol 33 (8) ◽  
pp. 50-55 ◽  
Keyword(s):  
Tracking Performance ◽  
Control Law ◽  
Longitudinal Control

Take-off characteristics and longitudinal controllability of FanWing

2016 ◽  
Vol 88 (6) ◽  
pp. 783-790 ◽  
Author(s):  
Lin Meng ◽  
Yongqiang Ye
Keyword(s):  
Deflection Angle ◽  
Rotation Speed ◽  
Cross Flow ◽  
Control Law ◽  
Great Success ◽  
Variable Cross ◽  
Longitudinal Control ◽  
Content Type ◽  
Cross Flow Fan ◽  
Practical Implications

Purpose This paper aims to study the short take-off characteristics and longitudinal controllability of FanWing. As a new structural plane, it has achieved great success at the air shows, but the existing literature is mostly on feasibility and prototype study while little on short take-off performance analysis and controllability. Thus, the paper will do some research on those two aspects. Design/methodology/approach This paper focuses on a certain type of a 3.5 kg FanWing and builds the longitudinal model based on its structure characteristics and operation principle. Its take-off process is simulated and the longitudinal control law is designed. Findings The short take-off performance and the large load characteristic are verified. To attain a better short take-off performance, several factors that influence the take-off distance are researched, and the optimal no-load take-off distance 5 m is obtained when the elevator deflection angle is −30°, the center of gravity is 0.42 m and the cross-flow fan rotation speed is 2500 r/min. The longitudinal controllability is verified through simulation. And without variable cross-flow fan rotation speed control, the longitudinal control of FanWing is the same to that of the conventional aircraft. Practical implications The presented efforts provide markers for designing the fan wing aircraft that would have better performances. And the control of FanWing is similar to that of a conventional airplane. Originality/value It is proved that FanWing can offer a better take-off performance through reasonable configuration. The paper also offers a useful reference on the control of FanWing.

H ∞ Based Adaptive Fuzzy Control of a Tower Crane System

2012 ◽  
Author(s):  
Mansour Karkoub ◽  
Tzu Sung Wu ◽  
Chien Ting Chen
Keyword(s):  
Fuzzy Control ◽  
Time Delays ◽  
Adaptive Fuzzy Control ◽  
Tracking Performance ◽  
Control Technique ◽  
Control Law ◽  
External Disturbances ◽  
Adaptive Fuzzy ◽  
Tower Crane ◽  
Highly Nonlinear

Tower cranes are very complex mechanical systems and have been the subject of research investigations for several decades. Research on tower cranes has focused on the development of dynamical models (linear and nonlinear) as well as control techniques to reduce the swaying of the payload. Inherently, the dynamical model of the tower crane is highly nonlinear and classified as under-actuated. The crane system has potentially six degrees of freedom but only three actuators. Also, the actuators are far from the payload which makes the system non-colocated. The dynamic model describing the motion of the payload from point to point is affected by uncertainties, time delays and external disturbances which may lead to inaccurate positioning, reduce safety and efficacy of the overall system. It is proposed here to use an H∞ based adaptive fuzzy control technique to control the swaying motion of a tower crane. This technique will overcome modeling inaccuracies, such as drag and friction losses, effect of time delayed disturbances, as well as parameter uncertainties. The proposed control law for payload positioning is based on indirect adaptive fuzzy control. A fuzzy model is used to approximate the dynamics of the tower crane; then, an indirect adaptive fuzzy scheme is developed for overriding the nonlinearities and time delays. The advantage of employing an adaptive fuzzy system is the use of linear analytical results instead of estimating nonlinear system functions with an online update law. The adaptive fuzzy scheme fuses a Variable Structure (VS) scheme to resolve the system uncertainties, and the external disturbances such that H∞ tracking performance is achieved. A control law is derived based on a Lyapunov criterion and the Riccati-inequality to compensate for the effect of the external disturbances on tracking error so that all states of the system are uniformly ultimately bounded (UUB). Therefore, the effect can be reduced to any prescribed level to achieve H∞ tracking performance. Simulations are presented here to illustrate the performance of the proposed control design.

scholarly journals Robust ℋ∞-Fuzzy Logic Control for Enhanced Tracking Performance of a Wheeled Mobile Robot in the Presence of Uncertain Nonlinear Perturbations

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3673 ◽  
Author(s):  
Nur Ahmad
Keyword(s):  
Fuzzy Logic ◽  
Mobile Robot ◽  
Wheeled Mobile Robot ◽  
Tracking Performance ◽  
Model Parameters ◽  
Control Law ◽  
System Modelling ◽  
Nonlinear Perturbations ◽  
Model Errors ◽  
Dc Motors

Motion control involving DC motors requires a closed-loop system with a suitable compensator if tracking performance with high precision is desired. In the case where structural model errors of the motors are more dominating than the effects from noise disturbances, accurate system modelling will be a considerable aid in synthesizing the compensator. The focus of this paper is on enhancing the tracking performance of a wheeled mobile robot (WMR), which is driven by two DC motors that are subject to model parametric uncertainties and uncertain deadzones. For the system at hand, the uncertain nonlinear perturbations are greatly induced by the time-varying power supply, followed by behaviour of motion and speed. In this work, the system is firstly modelled, where correlations between the model parameters and different input datasets as well as voltage supply are obtained via polynomial regressions. A robust H ∞ -fuzzy logic approach is then proposed to treat the issues due to the aforementioned perturbations. Via the proposed strategy, the H ∞ controller and the fuzzy logic (FL) compensator work in tandem to ensure the control law is robust against the model uncertainties. The proposed technique was validated via several real-time experiments, which showed that the speed and path tracking performance can be considerably enhanced when compared with the results via the H ∞ controller alone, and the H ∞ with the FL compensator, but without the presence of the robust control law.

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.

A System Level Study of the Longitudinal Control of a Platoon of Vehicles

1992 ◽  
Vol 114 (2) ◽  
pp. 286-292 ◽  
Author(s):  
Shahab Sheikholeslam ◽  
Charles A. Desoer
Keyword(s):  
Vehicle Dynamics ◽  
System Level ◽  
Control Law ◽  
System Study ◽  
Recent Past ◽  
Longitudinal Control ◽  
Control Laws ◽  
Preceding Vehicle ◽  
The Masses ◽  
Lead Vehicle

This paper presents a preliminary system study of a longitudinal control law for a platoon of nonidentical vehicles using a simplified nonlinear model for the vehicle dynamics. This study advances the art of automatic longitudinal control for a platoon of vehicles in the sense that it considers longer platoons composed of nonidentical vehicles; furthermore, the longitudinal control laws presented in this study take advantage of communication possibilities not available in the recent past. We assume that for i = 1, 2, . . . vehicle i knows at all times vl and al (the velocity and acceleration of the lead vehicle) in addition to the distance between vehicle i and the preceding vehicle, i − 1. A control law is developed and is tested on a simulation of a platoon of 16 vehicles where the lead vehicle increases its velocity at a rate of 3 m.s−2; it is shown that the distance between successive vehicles does not change by more than 0.12 m in spite of variations in the masses of the vehicles (from the nominal), of communication delay and of noise in measurements.

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