Design of speed controller for electronic fuel injection gasoline generator based on feed-forward PID control

As for the application of electronic fuel injection （EFI） system to small gasoline generator set, mechanical speed controller cannot be coupled with EFI system and has the shortcomings of lagged regulation and poor accuracy, a feed-forward control strategy based on load combined with proportional-integral-differential （PID） control strategy was proposed, and a digital speed controller applied to the electrical control system was designed. The detailed control strategy of the controller was intro- duced. The hardware design for the controller and the key circuits of motor driving, current sampling and angular signal captu- ring were given, and software architecture was discussed. Combined with a gasoline generator set mounted with EFI system, the controller parameters were tuned and optimized empirically by hardware in loop and bench test methods. Test results show that the speed deviation of generator set is low and the control system is stable in steady state; In transient state the control system responses quickly, has high stability under mutation loads especially when suddenly apply and remove 100% load, the speed deviation is within 8% of reference speed and the transient time is less than 5 s, satisfying the ISO standard.

Stabilization control of a bumblebee in hovering and forward flight

Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability （passive stability）. But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle （which can be measured by the sensory system of the insect）, to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

The Maximum Principle for Fully Coupled Forward-backward Stochastic Control System

The maximum principle for fully coupled forward-backward stochastic control system in the global form is proved, under the assumption that the forward diffusion coefficient does not contain the control variable, but the control domain is not necessarily convex.

Real-time Feed-forward Force Compensation for Active Magnetic Bearings System Based on H∞ Controller

There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings（AMB） system. And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration. The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted, which makes the real-time compensation not easily achieved. While the open loop method would not increase the primary transfer function order, it provides conditions for real-time compensation. But the real-time compensation signals are not easy to be obtained in the open loop method. To implement real-time force compensation, a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control. The method realizes real-time and on-line force auto-compensation based on H∞ controller and one novel feed-forward compensation controller, which makes the rotor rotate around its inertia axis. The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square（VSLMS） algorithm. And the relevant least mean square（LMS） algorithm parameters are used to solve the H∞ controller weighting functions. The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming, and real-time compensation is implemented in the actual AMB experimental system. The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞ controller to achieve close-loop control, and then real-time force unbalance compensation is implemented. The proposed research provides a new control strategy containing real-time algorithm and H∞ controller for the force compensation of AMB system. And the stability of the control system is finally improved.

Improved forwarding control design method and its application

Integrator forwarding is a recursive nonlinear design technique for the stabilization of feed-forward systems. However, this method still has some limitation. An improved design method is proposed to extend the field of application of this technique. This method is used to design a stabilizer for the inertia wheel pendulum system. Moreover, it is shown that the control Lyapunov function which is obtained from this method can also be used to design a globally asymptotically stabilizing controller with optimality.

FORWARD LINK PARTIAL-BALANCE POWER CONTROL ALGORITHM FOR W-CDMA COMMUNICATION

Balance power control is based on the idea of balancing Carrier to Interference Ratio (CIR) of all wireless links. Unbalance power control means that different traffics can achieve different CIR at receivers. This paper proposes a forward link partial-balance power control algorithm, which can provide necessary Quality of Service (QoS) for multimedia traffics in Wideband CDMA(W-CDMA) systems. The proposed algorithm is the integration of grading traffics priority and allocating and adjusting forward link power levels. For higher priority traffics, the unbalance power control is used. Whereas for lower priority traffics, balance power control is adopted. Computer simulation results show that the proposed algorithm can guarantee the special QoS requirements of the traffics with higher priority orders and maximize the CIR of the traffics with lower priority orders.

Laser-induced forward transferred silver nanomembrane with controllable light absorption

Laser processing provides highly-controlled modification and on-demand fabrication of plasmon metal nanostructures for light absorption and photothermal convention.We present the laser-induced forward tansfer(LIFT)fabrication of silver nanomembranes in control of light absorption.By varying the hatch distance,different morphologies of randomly distributed plasmon silver nanostructures were produced,leading to well-controlled light absorption levels from 11%to 81%over broadband.The anti-reflection features were maintained below 17%.Equilibrated and plain absorptions were obtained throughout all absorption levels with a maximum intensity fluctuation of±8.5%for the 225μJ cases.The 45μJ pulse energy can offer a highly equilibrated absorption at a 60%absorption level with an intensity fluctuation of±1%.Pattern transfer was also achieved on a thin tape surface.The laser-transferred characters and patterns demonstrate a localized temperature rise.A rapid temperature rising of roughly 15℃can be achieved within 1 s.The LIFT process is highly efficiently fabricated with a typical speed value of 10^(3)to 10^(5)cm^(2)/h.The results indicated that LIFT is a well-controlled and efficient method for the production of optical films with specific absorption levels.

Interlocking System for CBTC (Communication Based Train Control) System

In recent years,the environment of railways and the systems such as CBTC(communication based train control)have been changing.To respond the changes and the needs of customers,a UTCS(unified train control system)has been developed to realize a system that evolves with customers.Previous type systems consist of independent components such as ATC(Automatic train control)system,electronic interlocking system,and facility monitoring system,and there are a complicated overlap of system configurations and functions and difference in concept between the systems.On the other hand,the integrated train control system consists of horizontal layers such as function layer,network layer,and terminal layer.Therefore,the system has been developed to make it simple with no unnecessary redundancy and evolving to meet the needs of customers.In this paper,we explain a method that realizes the interlocking function for CBTC system in the function layer based on the concept of“securing a train travelling path”including path blocking and routing,and evaluate the safety of the method using STAMP/STPA.

Load Shedding Strategy Based on Combined Feed-Forward Plus Feedback Control over Data Streams

In data stream management systems (DSMSs), how to maintain the quality of queries is a difficult problem because both the processing cost and data arrival rates are highly unpredictable. When the system is overloaded, quality degrades significantly and thus load shedding becomes necessary. Unlike processing overloading in the general way which is only by a feedback control (FB) loop to obtain a good and stable performance over data streams, a feedback plus feed-forward control (FFC) strategy is introduced in DSMSs, which have a good quality of service (QoS) in the aspects of miss ratio and processing delay. In this paper, a quality adaptation framework is proposed, in which the control-theory-based techniques are leveraged to adjust the application behavior with the considerations of the current system status. Compared to previous solutions, the FFC strategy achieves a good quality with a waste of fewer resources.

Feed-Forward-Like Decoupling Control in Coagulation Bath of Carbon Fiber Precursor

The coagulation bath system of carbon fiber precursor is a complicated and multivariable coupling system. Based on the model of industrial production,the full dynamic decoupling control of the coagulation bath system of carbon fiber precursor is achieved in combination with multivariable feed-forward-like decoupling and proportional-integral-differential( PID) control. Compared with the conventional PID decoupling control,the experiment results show that the proposed method has a better control effect. The use of the controller can achieve complete decoupling of three parameters from coagulation bath system. The method should have great applications.

高管纵向关联与企业价值——“隧道效应”还是“监督效应”

高管纵向关联是加剧了大股东对小股东的利益侵占还是增强了对管理层的监督,是公司治理方向的一个重要问题。以2004—2019年上市公司为样本,手工整理了关联高管的详细信息。研究发现,高管纵向关联与企业价值呈显著负相关关系。机制检验结果表明,高管纵向关联通过加剧大股东掏空发挥了“隧道效应”。进一步研究显示,高管纵向关联与企业价值的负相关性在非国有企业、信息披露程度低的企业以及所处地区法律环境差的企业中更为明显;并且,存在高管直接纵向关联以及董事长纵向关联的公司往往表现出更低的企业价值。文章丰富了纵向关联高管的研究成果,对于提升上市公司治理水平具有重要实践意义。

基于变前视距离的四轮同步转向农机改进纯跟踪控制

路径跟踪控制是提高自主导航系统控制精度的关键。针对在复杂农田作业环境下转弯时纯跟踪算法跟踪精度不高的问题,本文提出了一种基于改进纯追踪模型的四轮同步转向农机路径跟踪控制算法。建立了基于四轮同步转向农机的运动学模型和纯跟踪模型,在此基础上考虑航向误差得到改进纯跟踪模型,进行RTK定位坐标修正,根据量化误差的评价函数搜索前视区域最优目标点,得到最优前视距离。本文算法能实时确定四轮同步转向农机改进纯跟踪模型中的前视距离,使航向误差和横向误差最小化,实现目标点的自适应优化。仿真结果表明,本文方法转弯时平均绝对横向误差减至0.035 m,平均绝对航向误差减至0.212°;水田实验结果表明,当四轮同步转向农机作业速度为3.6 km/h时,四轮转向农机轨迹跟踪平均绝对横向误差减至0.109 m,平均绝对航向误差减至2.799°,转弯跟踪精度显著提高。

基于DTN路由的多通路精准灌溉系统布局设计

为进一步提升我国智能灌溉装备的综合作业效率,从多通路实施与精准化控制角度展开布局设计。以灌溉系统的作业原理及田间信息获取特征为出发点,建立灌溉网络的DTN路由算法模型,实施网络节点的规划分配与通道布置,形成精准性的逻辑控制流程及节点网络相互执行关系。进行系统性的灌溉试验,结果表明:基于DTN路由算法的多通路精准灌溉系统布局正确可行,信息投递成功率可达94.13%,节点转发率可达96.07%,各信息传递的实时准确,各阀门组件的动作协调,综合灌溉效率实现了高于90%的优化目标,是DTN路由控制理念在灌溉装备领域的应用创新思路之一,具有较好的推广意义。

无线电能传输系统最大效率追踪及恒压输出复合控制方法

针对无线电能传输(WPT)系统的传输效率受耦合线圈之间的互感以及负载影响的特点,该文提出一种基于阻抗匹配技术的最大效率追踪及基于前馈PI控制的恒压输出复合控制方法。首先,对双边LCC型WPT系统的参数和传输效率进行分析,通过调整系统参数优化系统的传输效率。其次,在二次侧使用DC-DC变换器采用阻抗匹配的方法实现最大效率追踪,同时在一次侧采用DC-DC变换器利用前馈PI控制器闭环控制负载端电压实现恒压输出。该方法中,效率追踪和电压控制之间相互独立,互不干扰。此外,该方法还通过系统工作时的电路参数来估算线圈间的互感值,并通过线性拟合的方法对该估算互感值进行修正,得到更精确的互感估算值。最后,通过搭建实验平台验证了该方法的可行性和有效性。与PI控制相比,前馈PI控制方法在快速性和抗扰动性上均具有明显优势。

乙烯“三机”控制系统改造后的操作方式探讨

简述乙烯装置“三机”控制系统改造的内容、目的,介绍了改造后的新系统的操作条件和操作步骤,新系统以保护机组、防喘振为中心,三组超速保护、机组状态监护、机组联锁保护(紧急停车系统)结合汇集于1套ITCC系统中,为生产运行提供了安全、可靠的操作平台。使得“三机”控制系统性能得到提升,功能进一步完善,降低了操作负荷,在整合在一起的操作界面上实现对机组的全面控制和操作,提高了操作效率。

连锁董事如何影响上市公司审计费用?——基于中国A股上市公司的经验证据

以中国A股上市公司为样本,基于繁忙假说、共谋假说检验了连锁董事对上市公司审计费用的影响及作用机理。研究发现,连锁董事会增加上市公司审计费用,且连锁董事的广度与深度均能显著增加上市公司审计费用。影响机制检验表明,连锁董事提高了上市公司的财务风险,进而导致上市公司审计费用的增加。进一步研究发现,在内部连锁董事、非国有企业、机构投资者持股比例较高以及上市公司存在内部控制重大缺陷的情境中,连锁董事对上市公司审计费用的正向影响更强。相关结论进一步丰富了连锁董事任职和审计费用领域的理论研究,也可以为会计师事务所优化审计定价决策和上市公司完善公司治理制度提供参考。

双闭环控制的三相电压型PWM整流器的研究

针对传统的不控整流电路中网侧电流谐波很大、晶闸管相控整流电路中深控时网侧功率因数低和闭环控制时动态响应慢等问题,设计出一种引入脉冲宽度调制技术的三相电压型整流器。在完成三相电压型整流器的电压外环电流内环的双闭环控制系统设计的基础上,对其进行了仿真实验。仿真结果表明,与不控或相控整流电路相比,该三相电压型PWM整流电路中,不仅输入电流的谐波大大减小,电能可双向流动,能够实现整流和逆变状态下的单位功率因数运行,还可较好地抑制负载突变时直流侧电压的波动,从而显著提高系统的抗扰能力,真正实现绿色环保和高效节能的高度结合。

一种新型3-RRPU并联机构的运动学及鲁棒控制研究

针对现有的三平移并联机构大多正解不唯一、较难实现精确稳定运动控制的问题,提出了一种新的3-RRPU型三平移并联机构,同时研究了机构的运动学、动力学及轨迹跟踪控制方法。首先,运用螺旋理论分析了该机构三平移的原理,进行了驱动输入的选取与论证,对机构平台奇异性、驱动奇异性和支链奇异性进行了分析;其次,运用运动学理论建立了运动学模型,推导了位置正、逆解析解;再次,运用拉格朗日动力学理论建立了机构操作空间的刚体动力学模型;最后,提出了一种基于非线性反馈解耦的自适应滑模轨迹跟踪控制方法,以证明其控制稳定性,并基于动力学模型对空间轨迹跟踪精度和控制力矩进行了仿真分析。研究结果表明:3-RRPU并联机构的位置正解在一般位形下具有唯一性,机构的平台奇异位形和驱动奇异位形少且无支链奇异。该轨迹控制方法可使机构在载荷20 kg、速度0.18 m/s、加速度0.12 m/s 2下,实现0.002 m以内的高精度复杂轨迹跟踪;基于Sigmoid函数的轨迹控制方法还能有效削弱控制力矩的抖振,为实现工业领域高速、高精度、高性能的三平移运动提供了新方法。

面向学科竞赛的发球机器人设计与控制

以发球机器人的设计和控制为案例,涵盖机械结构设计、电子电路设计、单片机控制、机器视觉、运动学建模和控制调试等多个领域的知识综合。该机器人的机械结构主要包括捡球机构、传球机构、发球机构和底盘机构。底盘机构为机器人的移动提供动力,捡球机构用于捡取放置的待发球,结合视觉定位单元可实现待发球的准确定位和自动抓取,传球机构负责将待发传送到发球机构,由发球机构将待发球发射到目标区域。电气控制系统的主控芯片为STM32单片机,实现对各执行机构的协调控制。经制作样机测试,该发球机器人的发球方向和速度可控。

基于双估计强化学习结合前向预测控制的自动驾驶运动控制研究

运动控制研究是实现自动驾驶目标的重要组成部分,针对传统强化学习算法在求解中因单步决策局限而导致控制序列次优的问题,提出了一种基于双估计强化学习算法及前向预测控制方法结合的运动控制框架(DEQL-FPC)。在该框架中引入双估计器以解决传统强化学习方法动作值过估计问题并提高训练优化的速度,设计前向预测多步决策方法替代传统强化学习的单步决策,以有效提高全局控制策略的性能。通过虚拟驾驶环境仿真,证明了该控制框架应用在自动驾驶汽车的路径跟踪以及安全避障的优越性,保证了运动控制中的精确性、安全性、快速性以及舒适性。