Shou-Tao Peng

On robust bounded control of the combined wheel slip with integral compensation for an autonomous 4WS4WD vehicle

This paper presents a robust bounded controller that prevents an autonomous 4WS4WD vehicle from wheel skidding in presence of uncertainties of both tire/road condition and aerodynamic drag. For eliminating the steady-state error of path tracking, this control scheme incorporates integral compensation into a robust low-and high-gain technique, which in our earlier work has been introduced to achieve the anti-skidding. In comparison, this new proposed scheme ensures the path-tracking error can vanish asymptotically without incurring high-frequency chattering in the control signals. Simulation shows that, under the uncertainty effects, the proposed controller effectively limits the combined wheel slip and achieves the asymptotic path tracking. Moreover, the control inputs of wheel torque and wheel steering are coordinated well in response to this new control scheme.

Attitude Control of a Single Tilt Tri-Rotor UAV System: Dynamic Modeling and Each Channel's Nonlinear Controllers Design

This paper has implemented nonlinear control strategy for the single tilt tri-rotor aerial robot. Based on Newton-Euler’s laws, the linear and nonlinear mathematical models of tri-rotor UAVs are obtained. A numerical analysis using Newton-Raphson method is chosen for finding hovering equilibrium point. Back-stepping nonlinear controller design is based on constructing Lyapunov candidate function for closed-loop system. By imitating the linguistic logic of human thought, fuzzy logic controllers (FLCs) are designed based on control rules and membership functions, which are much less rigid than the calculations computers generally perform. Effectiveness of the controllers design scheme is shown through nonlinear simulation model on each channel.

On a Robust Bounded Control Design of the Combined Wheel Slip for an Autonomous 4WS4WD Ground Vehicle

This study presents a robust bounded control that prevents wheel skidding for an autonomous 4WS4WD vehicle under uncertain tire/road condition and aerodynamic drag. Constraint on combined wheel slip is incorporated as a priori in design to prevent the skidding. A robust low-and-high gain technique is used to suppress the path-tracking error and to enhance the utilization of the limited wheel slip. Simulation shows that, under the uncertain tire/road condition and aerodynamic drag, the proposed control scheme can effectively limit the combined wheel slip and achieve the goal of path tracking. Moreover, the control inputs of wheel torque and wheel steering are coordinated well during the path tracking.

On a modification approach to a class of Lyapunov-based robust controllers subject to input constraint

This paper presents an approach to the modification of a class of Lyapunov-based robust controllers when the input constraint needs to be taken into account. The approach shows advantages in enhancing the input utilization and in retaining the stability and the robustness of the original control. The modification comprises two stages. The first stage is to reshape the original control for satisfying the constraint and preserving the original control direction. The second stage is to apply a structure for enhancing the input utilization and retaining the stability and robustness developed in the first stage. In addition, an estimate of the stabilization region is employed to select the design parameters for the local, semiglobal, and global stabilization.

Estimation of the practical stability region of a class of robust controllers with input constraint

Abstract In this paper, new practical stability results are obtained from a class of proposed constrained robust controllers. Unlike the previous relevant work, the stability investigation is now extended to the actual control modification region. For the class of uncertain systems with an unstable nominal part, our results give a closer estimation of regions of attraction and of ultimate boundedness. The closed loop stability is shown to be maintained in a region where the modified control and its original are distinct.

Design Hybrid Evolutionary PSO Aiding Miniature Aerial Vehicle Controllers

Based on some sort of simplified fuzzy reasoning methods and PID parameters, many fuzzy-PID controller schemes are applied to control the complicated systems, recently. Mathematical optimization calculations are making in encouraging EP with PSO yielding a higher-quality solution. In this paper, a novel HEPSO algorithm as an improved variant of stochastic optimization strategy PSO, which assigns optimization to fuzzy-PID control gains, is established. The benefit integration design of the HEPSO algorithm structure is generating and updating the new parameters for the fuzzy-PID control schemes in the short setting and operation time. The proposed controllers have demonstrated performance to MAV models.

On the Practical Stability of Incorporating Integral Compensation Into the Low-and-High Gain Control for a Class of Systems With Norm-Type Input Saturation

This paper studies the practical stability of incorporating integral compensation into the original low-and-high gain feedback law. The motivation for the incorporation is for achieving output regulation in the presence of constant disturbances without the use of a very large high-gain parameter required in the original approach. Due to numerical accuracy, the employment of very large high-gain parameters to eliminate steady-state error has the potential for inducing undesirable chattering effect on the control signal. A set of linear matrix inequalities is formulated in this study to obtain the related design parameters, by which the incorporation can achieve both the practical stabilization and asymptotic output regulation in the presence of input saturation and constant disturbances. Furthermore, the saturation of the control input can be shown to vanish in finite time during the process of regulation. Numerical examples are given to demonstrate the effectiveness of the proposed approach.

A robust bounded control for an autonomous vehicle subject to combined wheel slip constraint

Abstract This paper presents a robust bounded control that prevents wheel skidding for an autonomous 4WS4WD vehicle under uncertain tire/road conditions with aerodynamic drag. Constraints on combined wheel slip are incorporated, a priori, in design to prevent skidding. A robust low‐and‐high gain technique is used to suppress the tracking error, and to enhance the utilization of the limited wheel slip. Simulation shows that, under uncertain tire/road conditions, with aerodynamic drag, the proposed control scheme can effectively limit the combined wheel slip, and it achieves the goal of path tracking. Moreover, the control inputs of wheel torque and wheel steering are coordinated well during vehicle cornering.

On one approach to constraining wheel slip for the autonomous control of a 4WS/4WD vehicle

This work presents an approach to constraining wheel slip for the automatic path tracking control of a four-wheeled steering and four-wheeled drive (4WS/4WD) vehicle. The approach deals with and limits the quasi-steady state of the longitudinal and lateral wheel slips. A new control structure of wheel torque and wheel steering is proposed to transform the constrained tracking problem to that of state regulation with norm-bounded control. For the transformed problem, a low-and-high gain technique and an integral compensator are introduced to construct the constrained controller so that the utilization of the constrained wheel slip can be enhanced and the steady state error of tracking can be eliminated. Simulation shows that the proposed scheme can render the 4WS/4WD vehicle tracking along the desired path within a prescribed threshold of wheel slip, and can provide satisfactory coordination between wheel torque and wheel steering.

An approach of constraining wheel slip for automatic path tracking control of 4WS/4WD vehicles

Abstract Constraining wheel slip can be applied to avoid vehicle skidding, especially on a slippery road. This paper presents an approach of constraining wheel slip for automatic path tracking control of 4WS/4WD vehicles. The approach integrates and limits the quasi-steady state of both the longitudinal and lateral wheel slips. A new control structure of wheel torque and wheel steering is proposed to transform the original constraint-tracking problem to that of state regulation with input constraint. For the transformed problem, a low-and-high gain technique and an integral compensator are introduced to construct the constrained controller, so that the utilization of the constrained wheel slip can be enhanced and the steady state error of tracking can be eliminated. Simulation shows that, on the snow road condition, the proposed scheme can render the 4WS/4WD vehicle tracking along the desired path within a prescribed threshold of wheel slip, and can provide satisfactory coordination between wheel torque and wheel steering