A method of torque control for independent wheel drive vehicles on rough terrain

Our previous research has revealed that, for vehicles with independently driven wheels, a torque distribution based on the ratio of the vertical load of each wheel to the total vehicle load is efficient for driving on flat ground. In this research, this method of torque distribution was extended to electric off-road vehicles driving on rough ground. In order to examine the driving efficiency of these vehicles, a numerical vehicle model was constructed in the pitch plane. Simulations using the numerical vehicle model on rough ground were conducted with a proposed torque distribution and control method. The numerical results from these simulations were compared with those of a conventional vehicle to evaluate the driving efficiency and trafficability on ground with various profiles. A comparison between the simulations demonstrated that the proposed method of torque distribution to the front and rear wheels based on the ratio of the vertical load is efficient for driving on rough ground.     

杆状弯曲行波型超声电机运动机理研究

为了深入研究杆状弯曲行波型超声电机的运动机理，本文分析了定子表面质点椭圆运动轨迹的形成，并将椭圆运动分解为产生驱动力的有效椭圆运动与使定、转子产生径向滑动的径向直线运动；然后基于有效椭圆运动变化情况，分析了在两相振幅不平衡和任意相位差情况下对转子运动平稳性的影响，为这类电机的设计和性能控制提供理论依据。     

超声马达摩擦学及其摩擦材料研究进展

超声马达是一种新型原动机，与普通电磁马达不同，这是一种摩擦驱动马达．为了促进超声马达的发展，对其研究中关于定子与转子界面接触驱动特性和摩擦磨损特性，超声波振动对定子和转子接触界面摩擦学特性的影响，转子摩擦材料的选择及其寿命预测等，从摩擦学角度对国内外的研究进展进行了综合归纳与评述，并且针对超声马达摩擦驱动的特点，提出了当前值得重视的一些研究内容．     

自主气体轴承控制系统分析及实验研究

提出1种采用音圈电机作为可控节流器的自主电控式气体轴承新方案,可以有效提高大型光电精密仪器回转基准的精度,在实时测量回转基准径向运动误差的同时,通过主动节流器自主调节气场分布而产生控制力和调节轴承的偏移位置,达到减小径向运动量和提高回转精度的目的,同时分析了整个系统数学模型,设计了控制补偿器.采用自主控制方案后,轴承回转精度从控制前的0.3 μm提高到约0.08 μm.结果表明,该轴承系统具有良好动态品质和较高回转精度,能够广泛用于航空航天高精密惯导测试设备中.     

超声马达转子摩擦材料厚度对驱动性能的影响研究

制备了一系列不同厚度的摩擦材料 ,利用超声马达摩擦特性模拟试验装置 ,研究了摩擦材料厚度对超声马达空载转速和堵转力矩的影响 .基于一个简化的行波超声马达定子和转子接触模型 ,用有限元法计算了定子和转子接触变形随摩擦材料厚度的变化规律 ,提出了定子和转子具有合理接触变形的摩擦材料厚度范围 .根据试验和理论计算结果确定了摩擦材料最佳厚度 ,为超声马达摩擦材料厚度设计提供了理论依据     

薄型超声电机与定子振动模态的激发

论述了薄型超声电机的工作机理。分析了电机压电片的布置与激励信号的关系，探讨了定子弯曲模态的激发问题。设计并制作了一种新的薄型超声电机。电机转子安装在圆环定子内，能够显著减小电机厚度，电机定子采用双压电片结构，可以避免激发出定子的非轴称模态。完成了电机运转实验，电机运转平稳。     

Characteristic model of travelling wave ultrasonic motor

In general, the design and analysis of ultrasonic motor and motor’s control strategy are based on mathematical model. The academic model is widely used in the analysis of traveling wave ultrasonic motor (TWUSM). But the dispersive characteristic of piezoelectric ceramics and other complicated process, such as the friction, make the model’s precision not so accurate. On the other hand, identification modeling method, which is built based on the tested data, has obtained increasing application in the study of ultrasonic motor’s control technology. Based on the identification model, many control strategies can be designed easily. But the identification model is an approximate model, so if a more accurate model of ultrasonic motor can be obtained, the analysis and design of motor control system will be more effective. Characteristic model is a kind of identification model which can accurately describe the characteristics of TWUSM. Based on the tested data, this paper proposes the modeling method of ultrasonic motor’s characteristic model. The paper also makes a comparison of the effectiveness of different identification algorithms. Aiming at the speed control of ultrasonic motor, the influence of the parameter’s initial values on the precision of model is discussed. The calculating results indicate the availability of this characteristic model.     

空时非对称分数阶类Langevin棘齿

研究了空时非对称分数阶类Langevin分子马达棘齿模型,其中势函数是空间对称破缺的周期势,时间非对称类Langevin噪声由Logistic映射生成,而分数阶则刻画了分子马达工作环境的非理想程度.通过将模型转化为离散映射,即研究其整时间点情形,数值模拟了噪声的时间非对称性、势函数的空间非对称性以及分数阶对模型定向输运行为的影响.数值模拟结果表明:噪声的时间非对称性是定向流产生的根源,而势函数的空间非对称性能够与其进行竞争与协作,并在适当的参数条件下导致定向流的逆转;分数阶仅影响定向流的大小而不改变其方向.与经典的整数阶分子马达模型或时间非对称分数阶分子马达棘齿模型相比,该模型可以更为真实地描述分子马达的噪声整流工作机理.     

Drift coefficients of motor proteins moving along sidesteps

In the paper, we investigate two motor proteins moving along the sidesteps： a motor protein moving along a two- dimensional sidestep and another protein moving along a three-dimensional sidestep. The drift coefficients （or stationary average velocities） of these two motor proteins are calculated. We believe that our investigation of the motor proteins moving along the sidesteps in the present paper can benefit the investigation of the transport of the motor proteins to some extent.     

电感耦合等离子体发射光谱法测定E10乙醇汽油中的钠和锌

车用乙醇汽油是一种新型、清洁的汽车燃料,在燃烧过程中,微量的重金属杂质对汽车的行驶和养护有着至关重要的影响,一些燃烧产物可能会污染环境,威胁人们的身体健康,因此有必要对其中的微量元素进行控制。以异辛烷稀释汽油样品,电感耦合等离子体发射光谱（ICP-OES）法测定车用E10乙醇汽油中钠、锌含量的方法,选择钠和锌的分析谱线分别为：589.592和213.857 nm,实验优化了雾化气流量和蠕动泵速率对信背比的影响,应用了半导体制冷雾化系统（雾化室温度设置为-10 ℃）降低了进样过程中溶液的挥发性,保证了等离子体的稳定性,同时,实验研究了稀释比、内标元素以及稀释剂的类型对测定结果的影响,结果表明：（1）在-10 ℃低温下选择航空煤油为稀释剂,钠和锌的回收率均在120%以上,Y内标比值均在1.20以上,异辛烷为稀释剂时回收率和内标比值均满足要求,可能是航空煤油在低温下的密度和黏度较大导致,得出低温条件下异辛烷比航空煤油更适合作为乙醇汽油的稀释剂;（2）当选择Co做为内标元素时,有些样品的内标元素比值在120%以上,Y为内标元素时,样品的内标元素比值均满足要求,可能是由于Co的稳定性较差或样品里含有Co,得出Y比Co元素更适合做为乙醇汽油的内标元素;（3）本方法的钠和锌元素的检出限分别为0.013和0.005 mg·kg-1,加标回收率为85.1%～106.0%,相对标准偏差(RSD,n=7)为1.0%～4.8%;（4）通过与微波消解-ICP-OES法进行比较,本方法的测定结果与加标理论值较接近,弥补了微波消解法元素易损失的缺点。此法具有快速、灵敏、准确的优点,可应用于乙醇汽油中钠和锌元素的监测。