Development Of Cvt Control System And Its Use For Fuel‐Efficient Operation Of Engine

Continuously variable transmission (CVT) provides an automobile with the ability to change the gear ratio continuously, which can then improve not only ride quality such as acceleration performance but also fuel‐efficiency. However, to take advantage of the ability, a control system that can precisely control the gear ratio is required. This paper proposes such a control system for a belt‐driven CVT system. For controller design, first the CVT system is modeled by analytical and experimental approaches. The resultant static and dynamic characteristics provide a nonlinear first‐order model with an uncertain time constant and time delay. The nonlinear steady‐state gain is adjusted to one by a gain‐scheduled pre‐compensator. Thereby the plant model becomes a linear first‐order lag system with a dead time. The next step is controller design using the plant model. To guarantee stability and control performance against the parameter variation and time delay, the μ‐synthesis, a robust control method, is employed for feedback control. In addition, a feedforward controller is incorporated into the feedback control system to obtain better output response. The feedforward controller is given by a combination of the inverse system of the plant and a reference model that gives desired output response. As a result, the control system becomes a two‐degree‐of‐freedom control system. To evaluate the performance of the control system and its effectiveness on the fuel‐efficiency, computer simulation and driving tests were conducted. The simulation and experiment results prove that the proposed control system can make the gear ratio track a reference output quickly and precisely in the presence of the uncertainties. The results also show that the control system improves fuel‐efficiency by changing the gear ratio so that the engine torque and its revolution speed can satisfy optimum‐efficiency operating condition.     

基于ROS的蛇形机器人基本仿生运动与自主爬台阶控制

设计了一种带正交关节和主动轮组合的蛇形机器人。该机器人不仅能够实现基本的蜿蜒运动、纵向行波运动、横向翻滚运动和横向行波运动,且针对台阶式障碍物提出了一种自主爬越台阶的控制策略。机器人通过激光测距传感器与头部关节的仰角得到台阶高度,抬起相应高度的关节将头关节搭在台阶上,控制主动轮的推进速度与关节抬起的角速度相结合的方式达到上台阶的目的,并且在运动过程中将头部俯仰关节舵机的负载反馈作为判别下台阶的条件。基于ROS （robot operating system）构建了蛇形机器人仿真模型,并通过仿真与实验验证了机器人的基本运动控制和自主爬台阶控制策略的有效性。     

Guidance control of a wheeled mobile robot with human interaction based on force control

This paper presents a mobile robot carrier designed to carry a person using two modes: a mechanism with full support and another with partial support. The carrier is driven through guided control from an operator. Applied force is sensed by a force sensor mounted on the bottom of the handle. The measured force is filtered by the impedance function that generates the desired velocity to drive the motors. The inner loop PID controller is then required to follow the desired velocity, which is the reference input to the system. The impedance function is designed to make the driving condition comfortable for the driver by smoothing out abrupt starts and stops. Feasibility tests on the application of the impedance force control method to the carrier robot have been performed through experimental case studies aimed at evaluating the comfort level of prospective users: one is on a full support case when a user is riding on the carrier and another on a partial support case where the user is pushing the carrier.     

Analysis of active vibration control of multi-degree-of-freedom flexible systems by Newmark method

A flexible robot arm can be modeled as a lumped-parameter multi-degree-of-freedom mass–spring system. The actuator at one end positions the payload at the other end. The flexibility causes the vibration of the payload at the end point. This paper considers a 4-degree-of-freedom mass–spring system. A closed loop active vibration control system is analyzed to suppress the end-point vibrations. The mathematical model of the system is established by using the Lagrange equations. The average of the displacements of the masses is used for the feedback. A PID control is applied. The numerical solution is obtained by integrating the control action into the Newmark method. The instantaneous average displacement is subtracted from the reference input to find the error signal value at a time step in the Newmark solution. The PID control action is applied to find the actuator signal value in the time step. This input value is used to find the displacements for the subsequent time step. The process is continued until the steady-state value is approximately reached. The analytical solution is given by using the Laplace transform method to check the validity of the Newmark solution. It is observed that the numerical and analytical results are in good agreement. The integration of the control action into Newmark solution as presented in this study can be extended to finite element solutions to simulate the control of complex mechanical systems.     

基于时间细分技术的高精度自动定位控制方法研究

针对采用步进电机进行微步驱动时易出现"爬行"和步距角过大的现象,提出了一种基于时间细分技术的高精度自动定位控制方法,并研制了相应的控制系统.该方法通过在每个电机步距运动时间内对反馈元件进行高频采样,实现了对步距的细分和对运动的闭环控制.控制系统采用嵌入式微处理器和现场可编程逻辑阵列构建,并与采用步进电机直接驱动滚珠丝杆的机械载物台进行联机测试.测试结果表明,系统可以控制步进电机在不进行高倍细分的条件下的精确定位,具有较高的应用价值.     

Measuring and reducing axial motion of flat belt by finite element analysis

A simulation method for estimating and reducing axial motion of flat belt is developed by using a commercial finite element (FE) code, MARC. The simulated results of the axial motion rate have good agreement with the experimental ones. This research further shows that the axial motion of flat belt can effectively be reduced by setting an added steering roller to center position of the belt loosen span. Observing the deflected configuration of belt centerline and its expanded shape on two roller surfaces, we find a phenomenon that the belt wraps on the roller surface spirally and rotates with the roller without slippage. The mechanism of the belt axial motion is clarified in this paper.     

步进电机一体化控制系统的设计

本文应用单片机、步进电机驱动芯片、字符型LCD和键盘阵列,构建了集步进电机控制器和驱动器为一体的步进电机控制系统。二维工作台作为被控对象通过步进电机驱动滚珠丝杆在X/Y轴方向联动。文中讨论了一种以最少参数确定一条圆弧轨迹的插补方法和步进电机变频调速的方法。步进电机控制系统的开发采用了软硬件协同仿真的方法,可以有效地减少系统开发的周期和成本。最后给出了步进电机控制系统的应用实例。     

液压位置伺服系统同步的控制

针对无缝钢管生产线轧机两侧液压位置伺服系统内部参数不同和外界干扰不一致造成轧辊压下位置不同步的问题,设计了基于模糊输出反馈的液压位置伺服同步控制系统,并从理论上证明了该控制系统的稳定性。仿真结果表明,在轧机两侧内部参数不同和外部干扰差异的情况下,基于模糊输出反馈的液压位置伺服同步控制系统不仅具有较短的同步时间并且跟随误差更小。     

轧机速度系统积分反步控制器的研究

本文给出了轧机速度系统的积分反步控制器设计方法,此方法通过逐步修正算法设计镇定控制器,实现系统的全局调节或跟踪．在每一步把状态坐标变换和一个已知Lyapunov函数的虚拟控制系统的镇定函数等联系起来,最终得到一个控制李稚普诺夫函数(clf).然后．基于上述方法设计了直流电机驱动的轧机速度系统非线性反馈控制器,用来说明积分反步法也适用于线性系统、仿真研究结果表明．本文所设计的反馈控制器使闭环系统稳定,且使系统具有良好的跟踪性能。     

Variable admittance force feedback device and its human-robot interaction stability

In teleoperation, a force feedback device is a medium to build a transparent interaction environment between a human and a remote robotic arm. Using force feedback devices, the users can operate the remote robotic arm intuitively and perceive remote interaction through the force channel, just as if they are in the remote environment. Compared with impedance devices, admittance devices have the advantages of large feedback output, high stiffness, high reverse driving performance, and flexible structure, which are more suitable for the teleoperation of heavy-duty and large-size robotic arms. However, the control of admittance devices is relatively complex and has some inherent limitations such as response delay, instability from high-frequency oscillation, difficulty in achieving constant speed control, etc. Errors in admittance model parameters and human physiological characteristics, such as force application fluctuations, are the root causes of these problems. In this study, we proposed a fuzzy variable damping admittance algorithm, which allows the device to identify the user's movement intention and give respond quickly and accurately. We also established a human-robot interaction (HRI) system model of an admittance master controller device and summarized the principles of the admittance parameter configuration of a stable system. For the device's high-frequency oscillation instability caused by human arm stiffness, we propose an oscillation observation and reduction algorithm. By observing the force signal change characteristics, the algorithm can quickly detect the unstable behavior caused by human hands and perform oscillation reduction. To reduce the influence on upper limb uniform motion caused by fluctuating force application, we proposed a constant velocity intention inference algorithm based on a velocity spherical cone to smooth out the device operating velocity to achieve smooth control. The method proposed in this study achieved stable control in a 6 DOF force feedback device as a master controller, and the effect has been verified by experiments.     

Yaw Moment Control Strategy for Four Wheel Side Driven EV

When four wheel side driven EV travals in steering or changes lanes in high speed, the vehicle is easy to side-slip or flick due to the difference of wheel hub motor and a direct effect of vehicle nonlinear factors on vehicle yaw motion, which would affect vehicle handling and stability seriously. To solve this problem, a joint control strategy, combined with the linear programming algorithm and improved sliding mode algorithm, which combines the exponential reaching law and saturation function was proposed. Firstly, the vehicle dynamics model and the reference model according with the structure and driving characteristics of four wheel side driven EV were set up. Then, introduced the basic method of the improved sliding mode variable structure control and complete the sliding mode variable structure controller design basic on vehicle sideslip angle and yaw velocity.The controller accomplish optimal allocation of vehicle braking force through a linear programming algorithm, according to yaw moment produced by the vehicle motion state. Single lane driving simulation results show that the proposed control strategy can not only control vehicle sideslip angle and yaw velocity well, but also accomplish good controlling of the vehicle yaw moment, so as to significantly improve the handling and stability of vehicle.     

面向变高度连续台阶的双足欠驱动步行稳定控制

针对欠驱动双足机器人在已知变高度台阶上的稳定控制,提出了一种基于自适应前馈算法的稳定步行控制策略．首先,考虑地面变形,将地面等效为“弹簧-阻尼”系统,并建立“机器人-台阶”耦合动力学模型．其次,将“机器人-台阶”这一“多输入-多输出”模型简化为由质心位移和速度构成的“单输入-单输出”模型．然后,使用变坡度斜坡等效变高度台阶,根据台阶高度确定等效斜坡倾角和机器人理想步长;同时引入自适应控制系数,并根据等效斜坡倾角调整该控制系数,实现质心对参考速度的跟踪．最后,在台阶高度变化小于0.032 m的环境中进行数值仿真试验,验证控制策略的有效性．仿真结果表明：本文提出的控制策略可以实现已知变高度台阶上的稳定步行．     

Tracking control of second‐order chained form systems by cascaded backstepping

A design methodology is presented for tracking control of second‐order chained form systems. The methodology separates the tracking‐error dynamics, which are in cascade form, into two parts: a linear subsystem and a linear time‐varying subsystem. The linear time‐varying subsystem, after the first subsystem has converged, can be treated as a chain of integrators for the purposes of a backstepping controller. The two controllers are designed separately and the proof of stability is given by using a result for cascade systems. The method consists of three steps. In the first step we apply a stabilizing linear state feedback to the linear subsystem. In the second step the second subsystem is exponentially stabilized by applying a backstepping procedure. In the final step it is shown that the closed‐loop tracking dynamics of the second‐order chained form system are globally exponentially stable under a persistence of excitation condition on the reference trajectory. The control design methodology is illustrated by application to a second‐order non‐holonomic system. This planar manipulator with two translational and one rotational joint (PPR) is a special case of a second‐order non‐holonomic system. The simulation results show the effectiveness of our approach. Copyright © 2002 John Wiley & Sons, Ltd.     

Sequential tuning methods of LQ/LQI controllers for multivariable systems and their application to hot strip mills

In this study, we propose such sequential tuning methods of multivariable optimal regulators that can be applied to the tuning of control systems under operation. In such tuning, it is desirable to change feedback gains only step by step, confirming that the control performance is actually improved in each step. The first method we propose is such that we design an optimal single-input regulator in each step, by paying attention to only one input of the plant while the feedback laws to other inputs are fixed to those obtained in the previous sequential tuning steps. On the other hand, the second method is such that all elements of the feedback gain are changed at once, while we are given the design freedom about how much we are to change the gain. These two methods as well as their combined use are shown to lead to the optimal gain as a multivariable control system eventually, provided that the sequential tuning steps are repeated sufficiently many times. We apply these methods to the tuning of LQI servo systems, and carry out the simulation study of the control of a hot strip mill to illustrate the tuning law and show its effectiveness.     

轻型带式输送机及防逆风装置的研制与应用

针对现有普通带式输送机普遍存在故障点多、成本高、耗电量大、不易铺设和安装等缺陷,结合井下环境特点,研制了一种轻型带式输送机。该轻型带式输送机将原普通带式输送机传动部位改造为以卸载滚筒兼作电动机、联轴器、减速器、传动滚筒的传动装置,极大简化了普通带式输送机传动装置,实现了掘进工作面的集中控制;并利用手动蜗轮张紧装置替代了原有蜗轮、蜗杆张紧装置,使该轻型带式输送机具备结构简单、重量轻、安装维护方便等特点;同时实现了轻型带式输送机与防逆风装置的联锁,能有效防止掘进工作面原煤运输时风量流失,防止风流逆转和瓦斯进入进风流。     

Adaptive positioning control of an ultrasonic linear motor system

A 3PRR parallel precision positioning system, driven by three ultrasonic linear motors, was designed for use as the object stage of a scanning electron microscope (SEM). To improve the tracking accuracy of the parallel platform, the positioning control algorithms for the drive joints needed to be studied. The dead-zone phenomenon caused by static friction reduces the trajectory tracking accuracy significantly. Linear control algorithms such as PID (Proportion Integration Differentiation) are unable to compensate effectively for the dead-zone nonlinearity. To address this problem, two types of feedforward compensation control algorithms have been investigated. One is constant feedforward with the integral separation PID; the other is adaptive feedback and feedforward based on the model reference adaptive control (MRAC). Simulations and experiments were conducted using these two control algorithms. The results demonstrated that the constant feedforward with integral separation PID algorithm can compensate for the time-invariant system after identifying the dead-zone depth, while the adaptive feedback and feedforward algorithm is more suitable for the time-varying system. The experimental results show good agreement with the simulation results for these two control algorithms. For the dead-zone nonlinearity caused by the static friction, the adaptive feedback and feedforward algorithm can effectively improve the trajectory tracking accuracy.     

波纹辊轧机辊系主共振时滞反馈控制

金属复合板波纹辊轧制成形是一项变革技术,在复合板轧制成形的过程中,轧制界面的非线性阻尼以及上下波纹辊之间的非线性刚度都可能导致主共振的发生,造成辊缝的波动.考虑了波纹辊轧机波纹界面间的非线性阻尼和非线性刚度,建立了波纹辊轧机两自由度垂直非线性数学模型.利用奇异值理论和相平面法讨论了波纹辊轧机辊系自治下的稳定性,运用多尺度法求解了波纹辊轧机辊系在波纹界面激励下主共振的解析近似解和幅频特性方程.分析了非线性刚度系数、非线性阻尼系数、系统阻尼系数、轧制力的幅值等参数对主共振的影响.设计了线性和非线性复合作用的时滞反馈控制器来对波纹辊系的主共振进行控制,并且通过数值仿真验证了控制器设计的正确性和可行性.     

基于保辛算法的绳系卫星系统闭环反馈控制问题求解

应用非线性系统滚动时域控制的保辛算法求解绳系卫星系统子星释放和回收过程的闭环反馈控制问题.通过第二类Lagrange方程推导出二体绳系卫星系统的动力学方程;通过拟线性化方法将绳系卫星系统闭环反馈控制问题转化为线性非齐次Hamilton系统两端边值问题的迭代求解;通过保辛算法将线性非齐次Hamilton两端边值问题转化为线性方程组的求解;通过递进更新时间步的状态变量和控制变量,完成绳系卫星系统的闭环反馈控制.数值仿真表明:相对于Legendre伪谱方法,用保辛算法求解绳系卫星系统的闭环反馈控制问题的计算速度和收敛速度较快.绳系卫星系统的开环控制和闭环反馈控制问题数值仿真结果表明:在绳系卫星的初始状态存在偏差的情况下,使用开环控制会导致系统在终端无法达到稳定状态,而使用闭环反馈控制则能在一段时间内抵消初始状态向量偏差对系统产生的影响,最终达到稳定状态.     

Construction of an Omnidirectional Mobile Robot Platform Based on Active Dual-Wheel Caster Mechanisms and Development of a Control Simulator

In this paper, we describe a new type of holonomic and omnidirectional mobile robot using two driving assemblies, one of which consists of two independent driving wheel mechanisms, just like an active dual-wheel caster with an offset steered axis. Kinematic models of the wheel mechanism and a mobile robot with two driving assemblies are derived, and these models are applied to construct a feedback control system based on a resolved velocity control system for the robot. The effectiveness of the presented method is illustrated by some computer simulations. The prototype of a mobile robot platform using two driving assemblies, which can be controlled by a personal computer or a 3D joystick manipulated by human, is constructed.     

一种人头部实时跟踪方法

为了能够在视频监控、人机交互、视频会议等领域对人头部运动实施实时跟踪 ,给出了一种使用黑白摄像机对人平移或转身时的头部运动进行实时跟踪的方法 .该方法主要由基于块特征的跟踪和基于头部几何特征的校正两个步骤组成 .块特征跟踪算法仅利用图象低层信息而不依赖于目标的具体模型 ,可实现对头部自由运动的跟踪 .为解决块特征跟踪误差累积等原因造成的目标丢失问题 ,又采用了头部轮廓几何特征检验方法 ,根据跟踪窗口中头部轮廓位置的偏移来对块特征跟踪结果进行校正 .另外 ,为提高转身运动时相邻两帧图象的特征跟踪正确率 ,还引入圆柱模型来拟合头部 ,并在展开柱面内进行块特征选取和跟踪 .本文方法在 P 35 0微机上进行了实验 ,实验结果表明 ,系统能对长时间图象序列中人平移或转身时头部运动实施准确跟踪 .当跟踪窗口大小为12 0× 180 pixels,块特征数目为 80个时 ,系统的处理速度达到 30帧 /s