Speed Control of DC Motor using Composite Nonlinear Feedback Control

This paper presents the design of the composite nonlinear feedback (CNF) control law for DC motor speed control. First, a linear feedback control law is designed such that the closed-loop system under this linear control law has small damping ratio. Then, a nonlinear feedback part is designed based on this linear feedback law. The nonlinear function of the nonlinear feedback part is tuned by formulating the parameter tuning problem into a minimization problem. The minimization problem is solved by Hooke-Jeeves algorithm. The well designed CNF control law results in a satisfied transient performance with small overshoot, and fast rising time and settling time

Structural Design of Composite Nonlinear Feedback Control for Nonminimum Phase Linear Systems with Input Saturation

The general design procedure of composite nonlinear feedback (CNF) control does not consider the structure information of the system. As a result, the tuning of the nonlinear feedback gain is very difficult, especially for nonminimum phase systems. In this paper, a novel design method is proposed to construct a CNF control law by using the structure information of the system in a special coordinate basis (SCB) form. First, the system is transformed into the SCB form, in which the system is divided into three parts, i.e., stable zero dynamics part, unstable zero dynamics part, and integration part. For a nonminimuni phase linear system, a virtual linear feedback gain is designed to stabilize the unstable zero dynamics. With this virtual gain, the system can be transformed to an integration system which is connected to a stable system. Then, the CNF control law is tuned only for the integration part of the system. Since the target system is an integration system, the proposed method simplifies the tuning of the nonlinear function in the CNF design

Improving transient performances of vehicle yaw rate response using composite nonlinear feedback

This paper studies and applied the composite nonlinear feedback (CNF) control technique for improving the transient performances of vehicle yaw rate response. In the active front steering control design and analysis, the linear bicycle model is used for controller design while the 7DOF nonlinear vehicle model is used as vehicle plant for simulation and controller evaluations. The vehicle handling test of the J-turn and single lane change maneuvers are implemented in computer simulations in order to evaluate the designed yaw rate tracking controller. The simulation results show that the CNF technique could improve the transient performances of yaw rate response and enhance the vehicle maneuverability

Instability analysis of non-linear unmanned model helicopter control

针对无人机的飞行安全这一典型的系统工程问题,从目前国际惯用的非线性控制和辨识建模的角度出发,通过建立波动信息能量函数模型并结合模糊评价理论,量化分析了dfT变换对无人机系统建模和控制的不稳定性影响;通过对无人机非线性运动模型的分析,说明了该模型中各参数的不稳定关系和不稳定特征,提出了符合SHIlnIkOV定理的三阶非线性模型;通过构造综合影响函数和进行参数配置,确定了无人机非线性运动模型的若干鞍焦点和异宿轨道,从而找到了该系统的若干混沌运动轨道.最后通过仿真证明了直升机非线性运动模型的混沌运动特征和运用dfT辨识模型进行控制的条件下出现无人机不稳定性现象,说明了无人机非线性运动模型混沌运动的存在性及dfT变换中的高阶能量损失和参数配置方式的共同作用模式可构成无人机系统不稳定性的条件.For a typical system engineering problem of unmanned airplane vehicle flight safety,the paper quantitatively analysised the instability effects between the DFT transform and modeling control of the UAV system through the establishment of fluctuation energy function and the combinations of fuzzy evaluation theory from the current international practices perspective of nonlinear controlling and modeling identification,gave out the instability relationship between the parameters and their instability characteristic of the nonlinear motion model of helicopter through the analysis of the modeling process,raised the three-order nonlinear model in line with Shilnikov theorem,showed the possibility of the existence of chaotic orbits.By constructing the comprehensive effect function and parameter configuration,a number of saddle-focus and heteroclinic orbits were discovered.Finally,the chaotic motion characteristics of the non-linear model were proven by stimulation,and the conditions and causes of the existence of the instability were listed by DFT identification model.Additionally,the existence of chaos in a UAV nonlinear motion model was proven.The common mode action of high-level energy loss in DFT transformation and the configuration of parameters constitute the conditions under which a UAV system is not stable.国家985工程二期信息平台建设(0X0007);国家自然科学基金资助项目(61070151);福建省自然科学基金资助项目(2010J01353

A Review of Active Yaw Control System for Vehicle Handling and Stability Enhancement

Yaw stability control systemplays a significant role in vehicle lateral dynamics in order to improve the vehicle handling and stability performances. However, not many researches have been focused on the transient performances improvement of vehicle yaw rate and sideslip tracking control. This paper reviews the vital elements for control system design of an active yaw stability control system; the vehicle dynamic models, control objectives, active chassis control, and control strategies with the focus on identifying suitable criteria for improved transient performances. Each element is discussed and compared in terms of their underlying theory, strengths, weaknesses, and applicability. Based on this, we conclude that the sliding mode control with nonlinear sliding surface based on composite nonlinear feedback is a potential control strategy for improving the transient performances of yaw rate and sideslip tracking control

Control of MacPherson active suspension system using sliding mode control with composite nonlinear feedback technique

The MacPherson active suspension system is able to support the weight of vehicle and vibration isolation from road profile, and is also able to maintain the traction between tyre and road surface. It also provides both additional stability and maneuverability by performing active roll and pitch control during cornering and braking, and the most significant are ride comfort and road handling performance. However, a drawback of MacPherson model is the self-steer phenomenon in the active suspension system. The problem might be solved by controlling the actuator force and control arm of the system. The MacPherson model has a similar layout to a real vehicle active suspension system. The mathematical model of the system produces a nonlinear mathematical model with uncertainties. Therefore, the proposed control strategy must be able to cater the uncertainties in mathematical model and simultaneously provide a fast response to the system. The control strategy combines Composite Nonlinear Feedback (CNF) algorithm and Proportional Integral Sliding Mode Control (PISMC) algorithm to achieve quick response and to reduce uncertainties. Optimisation of parameters in the CNF was performed using Evolutionary Strategy (ES) algorithm for fast transient performance. Thus, the controller is called Proportional Integral Sliding Mode Control – Evolutionary Strategy – Composite Nonlinear Feedback (PISMC-ES-CNF). To validate the proposed controller, the conventional Sliding Mode Control (SMC) and CNF were utilised to control the system under various road profiles. The ISO 2631-1, 1997 was used as a reference of ride comfort level for the acceleration of sprung mass. Results show that the proposed controller, PISMC-ES-CNF achieved the best control performance under various road profiles. The results obtained also prove that the PISMC-ES-CNF managed to improve ride comfort quality and road handling quality and has also delivered better control performance in terms of transient response of acceleration of sprung mass, reducing overshoot and chattering problem compared to conventional SMC and CNF

Composite nonlinear control with state and measurement feedback for general multivariable systems with input saturation

10.1016/j.sysconle.2004.09.010Systems and Control Letters545455-469SCLE

Composite Nonlinear Control with State and Measurement Feedback for General Multivariable Systems with Input Saturation

Proceedings of the IEEE Conference on Decision and Control54469-4474PCDC