兼顾平顺性与车高调节的重型车空气悬架控制

空气悬架由于质量轻、刚度以及高度可调等优点在重型车中得到了广泛的应用.空气悬架可以实现重型车的两项重要功能:平顺性保证以及车身高度调节,但是空气悬架的平顺性以及车身高度调节均通过空气弹簧气压腔的气压改变来实现,因此二者是彼此制约和冲突的.然而,目前对空气悬架车高调节的研究追求控制的精确性与稳定性而忽略了平顺性,而对平顺性的研究又几乎不考虑车高变化造成的影响.基于上述动机,本文提出了兼顾平顺性的空气悬架重型车车高调节鲁棒控制方法,实现了平顺性保障下的车高调节曲线精确跟踪控制,提升了重型车空气悬架系统的整体性能.实车参数仿真验证了所提出方法在平顺性与车高调节两项指标中的优越性.     

Optimal pitch map generation for scanning pitch design in selective sampling

The reverse engineering process represents one of the best known methodologies for creating three-dimensional (3D) virtual models starting from physical ones. Even if in the last few years its usage has significantly increased, the remarkable involvement of the operator has until now represented a significant constraint for its growth. Having regard to the fact that this process, and in particular its first step (that is the acquisition phase), strongly depends on the operator’s ability and expertise, this paper aims at proposing a strategy for automatically supporting an “optimal” acquisition phase. Moreover, the acquisition phase represents the only moment in which there is a direct contact between the virtual model and the physical model. For this reason, designing an “optimal” acquisition phase will provide as output an efficient set of morphological data, which will turn out to be extremely useful for the following reverse engineering passages (pre-processing, segmentation, fitting, …). This scenario drives the researcher to use a selective sampling plan, whose grid dimensions are correlated with the complexity of the local surface region analyzed, instead of a constant one. As a consequence, this work proposes a complete operative strategy which, starting from a first raw preliminary acquisition, will provide a new selective sampling plan during the acquisition phase, in order to allow a deeper and more efficient new scansion. The proposed solution does not require the creation of any intermediate model and relies exclusively on the analysis of the metrological performances of the 3D scanner device and of the morphological behaviour of the surface acquired.     

智能双车车距控制算法与优化策略

针对传统的车速与车距控制算法难以满足智能车竞赛双车追逐组别比赛要求的问题,提出一种速度距离双闭环控制策略,采用改进的模糊控制算法和增量式比例—积分—微分(PID)算法相结合,对速度和车距进行控制。实验结果表明:该算法及控制策略对双车车距的控制非常有效,在保证完成双车超车任务下,在行驶运动中仍可保持合适车距,适合性很强。     

自定位运动控制系统小车系统设计

为了实现小车自定位运动的功能,设计出基于GPS信息处理和电子指南针数据来控制车的行动轨迹从而实现自主导航的控制方案.以AVR单片机作为控制枢纽,通过相关硬件模块以及电路的设计实现对小车良好控制.电机与舵机直接由电池经过一些限流管供电实现稳定工作.实践检验,系统能够实现自定位功能,并能够按照一定的路线到达指定的位置.     

Human factors and use of amusement ride control interfaces

Amusement rides are a familiar form of recreation and an important component in the tourism industry, found in both fixed-site amusement parks and travelling carnivals. Standards governing design of the operator's control interfaces are broad and provide little specific direction about ideal design. This paper describes existing interfaces and their use, reports on a heuristic evaluation of carnival interfaces, and describes differences in ride-operation tasks across the domain. Differences in the ride-operation task create different control interface priorities in different contexts. Prevention of slips is the interface priority for multiple-operator rides, where function allocation and automation reduce the control decision-making required. Interfaces in single-operator rides and control towers must support operators to diagnose and respond rapidly and effectively to infrequent exceptional situations, and prevent mistakes by assisting situation awareness and making responses intuitive, along with minimizing the potential for slips.     

Nonlinear PI control for variable pitch wind turbine

Wind turbine uses a pitch angle controller to reduce the power captured above the rated wind speed and release the mechanical stress of the drive train. This paper investigates a nonlinear PI (N-PI) based pitch angle controller, by designing an extended-order state and perturbation observer to estimate and compensate unknown time-varying nonlinearities and disturbances. The proposed N-PI does not require the accurate model and uses only one set of PI parameters to provide a global optimal performance under wind speed changes. Simulation verification is based on a simplified two-mass wind turbine model and a detailed aero-elastic wind turbine simulator (FAST), respectively. Simulation results show that the N-PI controller can provide better dynamic performances of power regulation, load stress reduction and actuator usage, comparing with the conventional PI and gain-scheduled PI controller, and better robustness against of model uncertainties than feedback linearization control.     

Adaptive back-stepping pitch angle control for wind turbine based on a new electro-hydraulic pitch system

A new electro-hydraulic pitch system is proposed to smooth the output power and drive-train torque fluctuations for wind turbine. This new pitch system employs a servo-valve-controlled hydraulic motor to enhance pitch control performances. This pitch system is represented by a state-space model with parametric uncertainties and nonlinearities. An adaptive back-stepping pitch angle controller is synthesised based on this state-space model to accurately achieve the desired pitch angle control regardless of such uncertainties and nonlinearities. This pitch angle controller includes a back-stepping procedure and an adaption law to deal with such uncertainties and nonlinearities and hence to improve the final pitch control performances. The proposed pitch system and the designed pitch angle controller have been validated for achievable and efficient power and torque regulation performances by comparative experimental results under various operating conditions.     

赛场环境实时变化的帆船比赛最优路径规划

最优行驶路径规划是帆船比赛取胜的关键环节。文章提出了赛场环境参数实时变化时,基于模糊综合评价的帆船直航比赛最优路径规划方法。该方法利用模糊综合评价思想,综合考虑行驶速度和接近目标两个因素建立综合评价函数进行航行方向决策,赛场环境参数变化时,从当前航行位置相对目标点重新进行路径规划,保证局部状态始终最优,利用宽度优先搜索算法实现全局最优路径搜索。仿真结果证明,该路径规划方法能够取得较好的规划结果,对指导帆船运动员进行科学训练有很好的理论意义和应用价值。     

事件驱动的网络化系统最优控制

针对随机事件驱动的网络化控制系统, 研究其中的有限时域和无限时域内最优控制器的设计问题. 首先, 根据执行器介质访问机制将网络化控制系统建模为具有多个状态的马尔科夫跳变系统; 然后, 基于动态规划和马尔科夫跳变线性系统理论设计满足二次型性能指标的最优控制序列, 通过求解耦合黎卡提方程的镇定解, 给出最优控制律的计算方法, 使得网络化控制系统均方指数稳定; 最后, 通过仿真实验表明了所提出方法的有效性.

     

步进电动机的最佳细分控制

提出按照线性加工弦规律波形对步进电动机绕组电流进行细分，以解决在实际应用中存在的低频振荡、高频出力不足、频率特性差等问题。设计制作了同频脉宽调制细分驱动电路。试验结果表明该方法是正确和可行的。     

变桨距四旋翼飞行器控制系统设计

变桨距四旋翼飞行器是通过改变旋翼的桨距大小来改变升力的,这种控制策略可使飞行器姿态的响应和控制的延迟都会小很多,同时可以节省资源和能耗。通过分析对比变桨距与传统的变转速四旋翼飞行器的结构和飞行原理,根据其数学模型和控制要求,设计了变桨距四旋翼飞行器的控制系统。该系统采用STM32F427微处理器作为主控制器,使用MPU6000等惯性测量单元及其他传感器用于检测飞行器的位置、姿态;基于四元数方法进行姿态解算;利用PID控制算法对飞行器姿态、高度进行闭环控制。试飞结果表明,变桨距四旋翼飞行器能够稳定飞行,满足系统要求。     

Intelligent control for large-scale variable speed variable pitch wind turbines

Large-scale wind turbine generator systems have strong nonlinear multivariable characteristics with many uncertain factors and disturbances. Automatic control is crucial for the efficiency and reliability of wind turbines. On the basis of simplified and proper model of variable speed variable pitch wind turbines, the effective wind speed is estimated using extended Kalman filter. Intelligent control schemes proposed in the paper mchde two loops which operate in synchronism with each other. At below-rated wind speed, the inner loop adopts adaptive fuzzy control based on variable universe for generator torque regulation to realize maximum wind energy capture. At above-rated wind speed, a controller based on least square support vector machine is proposed to adjust pitch angle and keep rated output power. The simulation shows the effectiveness of the intelligent control.     

变采样网络控制系统的最优保性能控制

研究了一类不确定时延网络控制系统的最优保性能控制问题.针对线性时不变控制对象,控制器和控制对象采用时间-事件驱动,系统成为变采样网络控制系统,考虑在不确定时延小于或者等于一个变采样周期时,基于动态输出反馈对变采样网络控制系统进行建模,利用线性矩阵不等式研究了系统的保性能控制,并设计了保性能控制率和最优保性能控制率,最后给出实例表明在最优保性能控制率的控制下系统稳定.     

Data-driven dual-rate cascade control and application to pitch angle control of UAV

A data-driven design method for a cascade control system is proposed. The cascade control system consists of inner and outer loops, where the control interval of the outer loop is an integer multiple of the inner loop; hence, the system is a dual-rate system. In the proposed method, controllers in the inner and outer loops are designed based on one-shot data. In such a dual-rate cascade system, since the controllers are designed using different data-rate signals, the lifting technique is applied to align the dual-rate data. To show its effectiveness, the proposed method is compared with a conventional single-rate cascade control method, and numerical simulations and experiments are presented to examine servo and regulation performance.     

A new sliding mode controller for wind turbine pitch angle control

This paper focuses on variable-speed wind turbines where control is aimed at stabilizing the output power. A hybrid control algorithm is proposed which includes a new arrangement of two controllers along with an observer. Estimation of power coefficient via sliding mode observer reduces the amount of errors caused by changing the power coefficient parameter in different turbines. Moreover, the use of this special arrangement of sliding mode controller, proportional-integral (PI) controller and sliding mode observer, removes one of the controller parameter denoting wind speed from the designed algorithm, which in turn eliminates disturbances related to wind speed changes. In order to show the efficiency of the proposed control method, the performances of the controllers are evaluated by simulation in MATLAB software.     

Slit design for the thermal flying height control slider

In this work, we propose a novel thermal flying height control (TFC) slider, by designing a slit near the thermal heater in the slider. Design of the slit can reduce the mechanical constraints on the head elements and concentrate the heat around head elements. In turn, head elements can achieve more thermal protrusion and flying height reduction compared to the traditional TFC slider. The simulation results show that the application of the slit achieves a flying height reduction of 1.4 nm at writer and 1.7 nm at reader. Parametric study indicates that a trade off among the slit thickness (a), the distance of the slit to ABS (d) and thermal heater (t) should be optimized to achieve both large flying height reduction and small difference of flying height between reader and writer.     

Ergonomics standards and research for cars

This paper reviews some ergonomics tools available for car design, also an outline of how ergonomics principles and specific research have provided relevant information for designers. Further indications are given of the use of such ergonomics data in the development of in-house and ISO standards, as well as their subsequent influence on regulations. The two main areas discussed are symbols and electronic instrumentation. By the 1960s symbols were becoming a popular way of identifying controls and displays, especially for an international product. A simple experiment was conducted to relate the size of symbol to its ease of recognition. This yielded data which were used to establish an internal standard. The form of the symbols is perhaps more significant than the size. A number of experimental studies have been made of the ease with which drivers can relate symbols to the function and the ease with which these can be learnt. As a result, better symbols have been selected and in some cases the need for redesign shown clearly. This process has played a very important part in the formation of International Standards and in the harmonisation of regulations in many parts of the world. The advent of low cost electronics and electro-optical devices is beginning to influence car instrumentation. A substantial series of experiments has been conducted, concentrating on the format of the speedometer. This has shown clear advantages for digital instruments, although it also points to a few warnings. Various aids to the ergonomics design of electronic instruments are outlined.     

Optimal singular control for nonlinear semistabilisation

The singular optimal control problem for asymptotic stabilisation has been extensively studied in the literature. In this paper, the optimal singular control problem is extended to address a weaker version of closed-loop stability, namely, semistability, which is of paramount importance for consensus control of network dynamical systems. Three approaches are presented to address the nonlinear semistable singular control problem. Namely, a singular perturbation method is presented to construct a state-feedback singular controller that guarantees closed-loop semistability for nonlinear systems. In this approach, we show that for a non-negative cost-to-go function the minimum cost of a nonlinear semistabilising singular controller is lower than the minimum cost of a singular controller that guarantees asymptotic stability of the closed-loop system. In the second approach, we solve the nonlinear semistable singular control problem by using the cost-to-go function to cancel the singularities in the corresponding Hamilton–Jacobi–Bellman equation. For this case, we show that the minimum value of the singular performance measure is zero. Finally, we provide a framework based on the concepts of state-feedback linearisation and feedback equivalence to solve the singular control problem for semistabilisation of nonlinear dynamical systems. For this approach, we also show that the minimum value of the singular performance measure is zero. Three numerical examples are presented to demonstrate the efficacy of the proposed singular semistabilisation frameworks.     

Optimal traction control for heavy-duty vehicles

Heavy-duty vehicles such as tractors, bulldozers, certain construction and municipal vehicles, soil millers, forestry machinery etc. have a high demand for propulsion force and consequently a high fuel consumption. The current work presents a traction control approach based on motion dynamics estimation for optimizing propulsion force and energy efficiency according to a user-defined strategy. Unscented Kalman filter augmented with a fuzzy-logic system for adaptive estimation is used as the state observer. Simulation case study with an electrically driven tractor is presented. The new method of traction control showed considerable improvement of balancing energy efficiency and propulsion force.     

计算机病毒的最优控制模型*

提出一个带有最优控制的SAIC模型,让感染病毒的节点数目和系统消耗保持在较低的水平。运用最优控制理论的相关原理和方法,证明了最优控制的存在性,并给出了刻画最优控制的最优系统。数值仿真结果表明,使用适当的控制策略后,计算机病毒的传播得到了有效的控制。所提的方法有望成为一种有用的工具来控制计算机病毒的传播。