Vehicle Active Steering Control Research Based on Two-DOF Robust Internal Model Control

Because of vehicle＇s external disturbances and model uncertainties,robust control algorithms have obtained popularity in vehicle stability control.The robust control usually gives up performance in order to guarantee the robustness of the control algorithm,therefore an improved robust internal model control（IMC） algorithm blending model tracking and internal model control is put forward for active steering system in order to reach high performance of yaw rate tracking with certain robustness.The proposed algorithm inherits the good model tracking ability of the IMC control and guarantees robustness to model uncertainties.In order to separate the design process of model tracking from the robustness design process,the improved 2 degree of freedom（DOF） robust internal model controller structure is given from the standard Youla parameterization.Simulations of double lane change maneuver and those of crosswind disturbances are conducted for evaluating the robust control algorithm,on the basis of a nonlinear vehicle simulation model with a magic tyre model.Results show that the established 2-DOF robust IMC method has better model tracking ability and a guaranteed level of robustness and robust performance,which can enhance the vehicle stability and handling,regardless of variations of the vehicle model parameters and the external crosswind interferences.Contradiction between performance and robustness of active steering control algorithm is solved and higher control performance with certain robustness to model uncertainties is obtained.

Generalized Internal Model Robust Control for Active Front Steering Intervention

Because of the tire nonlinearity and vehicle＇s parameters＇uncertainties,robust control methods based on the worst cases,such as H_∞,μsynthesis,have been widely used in active front steering control,however,in order to guarantee the stability of active front steering system（AFS）controller,the robust control is at the cost of performance so that the robust controller is a little conservative and has low performance for AFS control.In this paper,a generalized internal model robust control（GIMC）that can overcome the contradiction between performance and stability is used in the AFS control.In GIMC,the Youla parameterization is used in an improved way.And GIMC controller includes two sections：a high performance controller designed for the nominal vehicle model and a robust controller compensating the vehicle parameters＇uncertainties and some external disturbances.Simulations of double lane change（DLC）maneuver and that of braking on split-μroad are conducted to compare the performance and stability of the GIMC control,the nominal performance PID controller and the H_∞controller.Simulation results show that the high nominal performance PID controller will be unstable under some extreme situations because of large vehicle＇s parameters variations,H_∞controller is conservative so that the performance is a little low,and only the GIMC controller overcomes the contradiction between performance and robustness,which can both ensure the stability of the AFS controller and guarantee the high performance of the AFS controller.Therefore,the GIMC method proposed for AFS can overcome some disadvantages of control methods used by current AFS system,that is,can solve the instability of PID or LQP control methods and the low performance of the standard H_∞controller.

Design of active disturbance rejection internal model control strategy for SISO system with time delay process

A novel control scheme of active disturbance rejection internal model control(ADRIMC) is proposed to improve the anti-interference ability and robustness for the dead-time process. The active anti-interference concept is introduced into the internal model control(IMC) by analyzing the relationship between IMC and disturbance observer control(DOB). Further, a design process of disturbance filter is presented to realize the active anti-interference ability for ADRIMC scheme. The disturbance filter is used to estimate an equivalent disturbance consisting of both external disturbances and internal disturbances caused by model mismatches.Simulation results demonstrate that the proposed method possesses a good disturbance rejection performance, though losing some partial dynamic performance. In other words, the proposed method shows a tradeoff between the dynamic performance and the system robust.

A New Approach to Robust and Fault Tolerant Control

In this paper, we shall summarize a new approach to robust and fault tolerant control proposed recently by the author. This approach is based on a variation of all controller parametrization. This robust and fault-tolerant control design consists of two parts: a nominal performance controller and a robustness controller, and works in such a way that when a component (sensor,actuator, etc.) failure is detected, the controller structure is reconfigured by adding a robustness loop to compensate the fault. We shall illustrate how this strategy works under various situations.

Intelligent Dynamic Inversion Controller Design for Ball and Beam System

The Ball and beam system(BBS)is an attractive laboratory experimental tool because of its inherent nonlinear and open-loop unstable properties.Designing an effective ball and beam system controller is a real challenge for researchers and engineers.In this paper,the control design technique is investigated by using Intelligent Dynamic Inversion(IDI)method for this nonlinear and unstable system.The proposed control law is an enhanced version of conventional Dynamic Inversion control incorporating an intelligent control element in it.The Moore-PenroseGeneralized Inverse(MPGI)is used to invert the prescribed constraint dynamics to realize the baseline control law.A sliding mode-based intelligent control element is further augmented with the baseline control to enhance the robustness against uncertainties,nonlinearities,and external disturbances.The semi-global asymptotic stability of IDI control is guaranteed in the sense of Lyapunov.Numerical simulations and laboratory experiments are carried out on this ball and beam physical system to analyze the effectiveness of the controller.In addition to that,comparative analysis of RGDI control with classical Linear Quadratic Regulator and Fractional Order Controller are also presented on the experimental test bench.

A modified structure internal model robust control method for the integration of active front steering and direct yaw moment control

Taking into account the nonlinearity of vehicle dynamics and the variations of vehicle parameters,the integrated control strategy for active front steering(AFS)and direct yaw control(DYC)that can maintain the performance and robustness is a key issue to be researched.Currently,the H∞method is widely applied to the integrated control of chassis dynamics,but it always sacrifices the performance in order to enhance the stability.The modified structure internal model robust control(MSIMC)obtained by modifying internal model control(IMC)structure is proposed for the integrated control of AFS and DYC to surmount the conflict between performance and robustness.Double lane change(DLC)simulation is developed to compare the performance and the stability of the MSIMC strategy,the PID controller based on the reference vehicle model and the H∞controller.Simulation results show that the PID controller may oscillate and go into instability in severe driving conditions because of large variations of tire parameters,the H∞controller sacrifices the performance in order to enhance the stability,and only the MSIMC controller can both ensure the robustness and the high performance of the integrated control of AFS and DYC.

Two fuzzy internal model control methods for nonlinear uncertain systems

Purpose-The purpose of this paper is to use the internal model control to deal with nonlinear stable systems affected by parametric uncertainties.Design/methodology/approach-The dynamics of a considered system are approximated by a Takagi-Sugeno fuzzy model.The parameters of the fuzzy rules premises are determined manually.However,the parameters of the fuzzy rules conclusions are updated using the descent gradient method under inequality constraints in order to ensure the stability of each local model.In fact,without making these constraints the training algorithm can procure one or several unstable local models even if the desired accuracy in the training step is achieved.The considered robust control approach is the internal model.It is synthesized based on the Takagi-Sugeno fuzzy model.Two control strategies are considered.The first one is based on the parallel distribution compensation principle.It consists in associating an internal model control for each local model.However,for the second strategy,the control law is computed based on the global Takagi-Sugeno fuzzy model.Findings-According to the simulation results,the stability of all local models is obtained and the proposed fuzzy internal model control approaches ensure robustness against parametric uncertainties.Originality/value-This paper introduces a method for the identification of fuzzy model parameters ensuring the stability of all local models.Using the resulting fuzzy model,two fuzzy internal model control designs are presented.

基于高阶内模的变参考轨迹鲁棒迭代学习控制

针对一类带有非重复不确定参数的线性离散系统跟踪批次变化的参考轨迹问题,提出一种双环控制结构的鲁棒间接型迭代学习控制(ILC)算法。通过在内环部分设计比例-积分(PI)型反馈控制器保证闭环系统沿时间轴方向的稳定性,实现前几批次对参考轨迹的快速跟踪。在外环部分,通过高阶内模(HOIM)描述参考轨迹变化规律,并设计一个基于内模原理的高阶比例(P)型ILC控制器提升系统在批次方向上对变参考轨迹的跟踪性能,实现对变化的参考轨迹精确跟踪。针对不确定性参数带来的扰动问题,设计一类性能指标函数,将系统模型在间接型ILC控制器作用下转换为等价的重复过程模型;基于重复过程模型稳定性理论,将保证系统具有沿批次鲁棒稳定的性能指标条件转换为线性矩阵不等式(LMI)。最后通过一类永磁电机的控制仿真验证了所提算法的有效性。

永磁同步电机电流环的二自由度内模控制

目前工业上在对永磁同步电机(permanent magnetic synchronous motor,PMSM)进行控制时,常认为电流环的调节过程远快于转速环的调节过程,进而忽略电流环中反电动势扰动项的变化。但对于采用PI控制且机械时间常数与电磁时间常数相差不大或更小的电机而言,若直接对电流环中的反电动势扰动项进行忽略,将会导致电机的动态响应性能恶化。为解决上述问题,本文首先建立了永磁同步电机调速系统的数学模型,并根据此数学模型推导了PI控制条件下电机动态性能变差的原因,以及反电动势扰动项能否进行忽略的条件,针对无法忽略的情况本文在传统内模控制的基础之上设计了一种二自由度内模控制器,该控制器具有2个可独立调节的参数,可分别调节电流环的跟踪特性与鲁棒特性和抗干扰特性。最后,利用Matlab/Simulink对所设计的二自由度内模控制器与传统的PI控制器进行对比仿真实验。结果表明,相比于PI控制器,所设计的二自由度内模控制器使电流环具有更好的跟踪性和鲁棒性,解决了特殊情况下电机动态响应性能变差的问题。

海底钻机机架的同步升降控制方案设计

为了满足新型海底连续管钻机对可变高度机架的功能需求,开展了机架升降控制方案设计。首先根据海底钻井工艺和深海服役环境,设计了一套基于超长行程柱塞缸和电液比例节流调速的双层机架升降方案及作业流程,具有结构紧凑、稳定性好、油缸及高压管线安装方便、开发成本低的优点。为了减轻大跨距偏载和水下洋流扰动等因素对同步运动控制过程的影响,采用四缸主从同步闭环控制结构,并根据系统理论模型设计了一种内模鲁棒性控制算法,通过调节滤波器时间常数来改善控制器动态特性,仿真结果表明该系统具有良好的抗干扰能力,为深海环境下的准确和稳定控制提供了依据。

基于IMC-NI方法的柔性机械臂鲁棒控制器设计

研究了一类带有不确定性柔性机械臂的控制设计问题,提出了一种新的基于内模控制的负虚(IMC-NI)方法。通过将IMC控制器参数求解问题转化为负虚控制综合问题,从而推导出一组负虚条件相关的矩阵不等式条件。同时提供了控制器设计过程中稳定多项式参数选择方法,以优化控制器性能。最后通过柔性臂仿真实验,表明IMC-NI方法比传统H_(∞)回路控制具有更好的鲁棒性和动态响应特性。

内模控制研究的新发展

概述了内模控制(IMC)的研究现状和新发展,详细论述了内模控制特别是非线性系统内模控制研究中的主要方面及其研究成果.首先介绍了内模控制中的各种建模方法,指出它们各自的优缺点,并根据内模控制的发展趋势着重分析了内模控制器的设计及其改进结构,内模控制与其他控制方法的结合方式等几个关键性问题.最后指出了内模控制研究中存在的一些混淆,并探讨了这一研究领域的发展方向.

电压型逆变电源输出电压IMC-PID控制技术研究

提出了一种带PD输出电压瞬时值反馈内环的内模控制(internal model control,IMC)-PID电压型逆变电源控制方案:PD瞬时值反馈内环提高系统的动态性能,IMC-PID外环保证系统的稳态性能。给出了详细的基于极点配置的内环PD控制器和外环IMC-PID控制器设计步骤和方法。该方案只需检测输出电压,控制器结构简单,分析设计容易。仿真和实验结果表明该控制系统不仅具有优良的动、稳态性能,而且有很强的鲁棒性。相对电压、电流双环控制方案而言,该文提出的方案控制器结构和分析更加简单,成本更低,鲁棒性更强。

基于采样控制理论的光电跟踪伺服系统内模控制

针对外部扰动对光电跟踪伺服系统精度的影响,对稳定回路提出了一种两自由度内模控制,将控制器的设计转化为标准的H∞优化问题,使得系统对模型误差及参数摄动具有较强的鲁棒性。采用jump变换、提升操作等采样控制系统的理论与方法来优化设计相应的鲁棒控制器,综合考虑了系统的多采样率行为及采样点间的动态特性。仿真结果表明,相比于传统的鲁棒控制器设计方法,所设计的多采样率控制器的鲁棒性能指标为1.4135,能够更真实地反映光电跟踪伺服系统的多采样率特性对系统鲁棒性能的影响,且具有较高的指令跟踪精度及较强的扰动抑制性能。本文的研究为高精度光电跟踪伺服控制系统的设计提供了新方法。

基于内模控制策略的自整定PID控制器

针对实际控制对象的模型不易建立、大滞后等特点 ,提出基于内模控制策略的继电型自整定方法 .对内模控制器的原理和继电型自整定方法详细分析后 ,结合两者的优点设计出PID控制器 ,并给出了参数整定方法 .仿真研究结果表明 :该方法不但有良好的鲁棒性 ,而且调节快速、参数整定方法简单、不依赖于对象模型的参数 。

内模控制在电流调节器中的应用

在永磁同步电机(PMSM)的矢量控制中,电机的调速范围很宽时,电阻、电抗等参数对d、q轴电流的控制产生较大的误差,从而影响控制精度和动态响应速度。基于磁场定向的控制原理,提出了永磁同步电机电流调节器的内模控制(IMC)设计。用矩阵奇异值分析了IMC电流调节器的鲁棒性,并将其应用于永磁同步电机转子磁场定向的矢量控制中。对电流调节器的传递函数进行了仿真并用数字信号处理器(DSP)实现电机矢量控制的运行实验,实验表明,用IMC电流调节器实现的电机调速,能够获得良好的跟踪性能和较高的稳态精度。

广义预测控制的鲁棒化改进

利用内模控制结构分析了广义预测控制在未建模动态鲁棒性方面的缺陷，提出采用失配滤波器以增强系统的鲁棒性。针对广义预测控制的特点，提出了次优失配滤波器的简单设计方法。

基于内模控制的永磁直线同步电动机速度控制

基于内模控制原理,在建立永磁直线同步电动机(PMLSM)非参数模型基础上,设计了PMLSM内模控制器。通过理论分析和仿真确定了决定内模控制器性能的参数取值范围,并进行了实验验证。结果表明,PMLSM内模控制系统跟踪调节性能好、鲁棒性强,能消除不可测干扰的影响。

基于内模控制的工业控制系统仿真器鲁棒PID控制器设计

内模控制是一种基于被控对象数学模型的新型控制器设计方法,所设计的控制器具有鲁棒性强、参数整定方便等优点,已经在一些工业场合中得到了应用。为了提高学生对于内模控制方法的理解水平,该文首先简要介绍了内模控制的基本原理和内模PID控制器设计方法,介绍了工业系统仿真器实验平台的构成,并推导了其数学模型的表达式,然后利用内模控制原理为其设计了鲁棒PID控制器,通过仿真软件进行了实验验证,结果证明了内模控制方法的有效性。

时滞系统的滤波器时间常数自调整内模控制

对于工业控制过程中的大时滞和时变系统,利用Smith内模控制原理设计方法,建立了滤波器时间常数λ的自整定方法,并建立了滤波器时间常数λ的模糊整定规则;通过在线调整滤波器时间常数λ来改善其闭环特性。仿真结果表明,对于在控制过程中过程对象与过程模型失配时,通过内模控制器的滤波器时间常数λ自整定;既改善了系统的控制品质又能提高控制系统的鲁棒性。且易于工程实现。