燃气动力弹跳机器人的设计与试验研究

以可燃混合气体为动力源,设计了一种燃气动力的弹跳机器人,包括弹跳驱动器和轮式运动机构。弹跳驱动器采用双活塞燃烧室结构及磁力锁紧机构,有效减小驱动器体积,有利于驱动器复位和废气排除。轮式运动机构包括车身和蜂窝车轮,车身作为驱动器载体,蜂窝车轮用于机器人落地缓冲。对车轮的径向、周向和切变模量进行等效计算,采用铁木辛柯梁理论对车轮进行静力分析,计算结果与试验数据吻合;利用LS-DYNA对车轮落地碰撞进行仿真,分析了落地冲击能量消耗。对机器人的弹跳运动进行规划,弹跳越障试验表明机器人可直接越过或跃上障碍物,验证了机器人的弹跳运动能力。该弹跳机器人的研究为提高地面移动机器人的未知复杂地形适应能力提供了一种可行的技术方案。     

六自由度轮式并联机器人及其构型方法

车轮是人类历史上最伟大的发明之一,在交通运输领域得到了广泛的研究与应用。将车轮这种特殊的运动副引入到传统并联机器人构型设计中,可以有效拓展并联机器人的工作空间。基于全方位轮的关联矩阵描述,将含车轮的串联支链构型综合问题转化为含车轮的关联矩阵求解问题,综合出两类含车轮的无约束串联支链,并分析了两类串联支链的受力稳定性。提出了两种六自由度轮式并联机器人新构型,分析了基于全向轮的轮式并联机器人的自由度属性,并成功研制出了一台实验样机。六自由度轮式并联机器人融合了移动机器人和传统并联机器人的优势,不仅具有移动效率高、移动范围广的优点,且具备在局部小范围内进行高精度六自由度操作的能力,可广泛应用于大型精密设备制造过程中的加工、运输、调姿和装配等工业操作。     

Long-term lubrication of momentum wheels used in spacecrafts—An overview

Momentum wheels are spacecraft actuators of large angular momentum used for the attitude control and stabilization of spacecrafts. The on-orbit performance of spacecrafts depends largely on the performance of the momentum wheels which in turn depends on its bearings and its lubrication. Currently, the life cycle of spacecrafts are aimed to be around 20–30 years. However, the increases in size, complexity and life expectancy of spacecrafts demand advanced technologies especially in tribology and in turn the development of more innovative lubrication systems for long-term operation. This article reviews the tribological requirements of momentum wheels and the various lubrication systems used in the past and raises a necessity to develop a new system to cope with the new requirements.     

Computer-aided design of a leg for an energy efficient walking machineLa conception assitee par ordinateur d'une jambe pour une machine marchante energetiquement efficace

Vehicles with legs instead of wheels have been studied for a number of years. One of the reasons for interest in such vehicles is that animals use only 10% as much energy as wheeled or tracked vehicles when traveling over rough terrain. The leg geometry is the most crucial aspect of the design since it strongly influences the efficiency of the vehicle. The legs should be simple in structure, and when the motion of the body is on a horizontal straight line, only one actuator per leg should be active in order to have good energy efficiency. The design of an energy efficient walking machine leg is described in this paper. In the design procedure, the motion of the leg is considered first, and a very simple leg developed from a 4-bar linkage and designed using a computer-aided interactive program is described. Second, the forces on this leg during a typical motion cycle are discussed. The leg is driven by a primary actuator for straight line walking and two secondary actuators which vary working height and change direction. A prototype of the leg is being built in The Department of Mechanical Engineering at The Ohio State University.     

Wheeled blimp : Hybrid structured airship with passive wheel mechanism for tele-guidance applications

This paper presents a novel design of indoor airship having a passive wheeled mechanism and its stationary position control. This wheeled blimp can work both on the ground using wheeled vehicle part and in the air using the floating capability of the blimp part. The wheeled blimp stands on the floor keeping its balance using a caster-like passive wheel mechanism. In tele-guidance application, stationary position control is required to make the wheeled blimp naturally communicate with people in standing phase since the stationary blimp system responds sensitively to air flow even in indoor environments. To control the desired stationary position, a computed torque control method is adopted. By performing a controller design through dynamic analysis, the control characteristics of the wheeled blimp system have been found and finally the stable control system has been successfully developed. The effectiveness of the controller is verified by experiment for the real wheeled blimp system.     

六轮车辆滑移转向动力学建模和运动特性分析

轮式滑移转向车辆由于其机动灵活和结构简单可靠而具有广泛的应用价值。针对一种六轮车辆,车轮触地点的速度分析、轮轴转动副摩擦分析和车辆力平衡关系,建立了稳态滑移转向时的动力学模型,分析了车辆主要结构参数和左右侧车轮转速的不同对滑移转向的瞬心位置、转向角速度和车轮所需力矩的影响规律。研究结果可为六轮车辆的合理设计和实现滑移转向时的轮速控制与驱动提供理论依据。     

基于两杆三索张拉整体结构的可变径柔性步行轮设计

为发挥轮式机器人移动速度快和腿式机器人机动性能强的优势,提出一种可实现轮式和腿式切换的新型张拉变径步行轮。通过对两杆三索平面张拉整体结构中拉压构件的等效替换,提出了一种新型张拉整体结构。在此基础上,给出了张拉变径步行轮的基本单元结构、单元连接方法和最优轮毂数。为克服由于自由度多导致刚性差的缺点,给出了张拉变径步行轮自由度约束的方法和弹性构件等效集成方式,从而使得张拉变径步行轮装配简单、运动平稳以及可负载支撑。结合最小势能原理对张拉变径步行轮张拉单元进行运动学分析,得到了张拉变径步行轮的结构参数和展收比。通过实验,对张拉变径步行轮各项功能的可实现性进行了验证。     

Experimental verification of a mathematical model of the wheel-supporting surface interaction during nonstationary rolling motion

A new mathematical model of the oscillating processes of complex systems of elastically deformed solids with superimposed nonholonomic rheonomous constraints under random perturbation is discussed in regards to the contact (tribological) interaction of a wheel and a supporting surface, torsional wheel oscillations, and transmission as applied to multiple-seated wheeled vehicles. The results of the testing of a vehicle by means of a stand with chassis dynamometers in stationary and nonstationary modes of wheel rolling motion are given. The obtained regularities make it possible to depict the picture of oscillations of the system under consideration, which will help to formulate complex requirements for the active safety control systems of multiaxis wheeled vehicles in the future.     

Development of a Lubrication System for Momentum Wheels Used in Spacecrafts

The success of any satellite mission largely depends upon the performance of the attitude control systems such as gyroscopes and momentum/reaction wheels. The required life and performance quality of these rotating mechanisms are ensured by the selection of bearings and its lubrication. The design and development of lubrication system to meet the long-term uninterrupted performance is a challenging task before the tribologists. This article describes the developmental study of a lubrication system for long-term requirements of momentum/reaction wheels. The developed system is compact and can be placed inside the bearing unit assembly. It works on centrifugal force and able to supply lubricant continuously at a very low rate of few micrograms per hour for many years. Further, the system can be tuned for any flow rate depending on the requirement.     

轮式移动机器人电机驱动系统的研究与开发

以嵌入式运动控制体系为基础,以移动机器人为研究对象,结合三轮结构轮式移动机器人,对二轮差速驱动转向自主移动机器人运动学和动力学空间模型进行了分析和计算,研究和设计了自主移动机器人电机驱动系统,开发了一套二轮差速驱动转向移动机器人电机驱动系统,完成了系统各部件的整体装配和调试。试验结果表明,该设计方案可行、系统运行稳定可靠、成本低廉、所用元件易于购置,具有较好的实用的价值和应用前景。     

Wheel-Walking Propulsion Unit of a Planetary Rover with Active Suspension

The scheme of the propulsion unit with walking mechanism for a wheeled planetary rover is considered. The walking mechanism permits to convert the chassis in a transport position, displacement of rover’s center of mass so as to optimize the load on motor wheels. In wheeled motion the walking mechanism realize function of the active suspension for adaptation of the locomotion system to the surface features. On friable soils where wheeled locomotion is difficult or impossible, wheel-walking mode improves trafficability.     

从动轮式复合机构机器人滚行时的动力学建模研究

综合轮式和步行机器人的特点 ,提出了从动轮式腿轮复合机构机器人的设想。然后 ,使用广义 L agrange方程推导了系统的动力学特性方程 ,得出机器人直线滑行速度表达式 ,在理论上证明了该设想是可行的。同时 ,使用 EXCEL 97进行了系统运动速度仿真 ,研究了其直线滑行时的动力学性能 ,讨论了系统摩擦力的确定方法 ,得出一些相关结论     

Stabilization of a bicycle with two-wheel steering and two-wheel driving by driving forces at low speed

Recently, the personal mobility vehicle (PMV), a vehicle suitable for personal use, has been developed. It moves at low speed and is sufficiently small that it can be ridden in pedestrian space. This vehicle is expected to be a new method of transportation that is practical and environmentally friendly. As one form of PMV, the authors propose a twowheel vehicle with two modes: a two-wheel steering and two-wheel driving bicycle mode and a parallel two-wheel mode. This vehicle has four electric motors, two for driving and two for steering, and one generator connected to the pedals. In the bicycle mode, the rider rotates the pedals to generate electric power, and the motors in the wheels produce torque using the generated energy. The front and rear wheels are steered by the electric motor according to the angle of the handle. Therefore, this bicycle is controlled by a steer-by-wire and a drive-by-wire system. In the parallel two-wheel mode, the vehicle is stabilized according to the theory of the inverted pendulum. In this paper, we focus on the bicycle mode and analyze its stability. Stabilizing the bicycle is not easy since the proposed vehicle has tires with small diameters and the traveling speed is assumed to be low. It is known that the stability of bicycles is tuned by adjusting the bicycle parameters and changing the rear steer angle. However, since we aim to use the vehicle in a narrow walking space at low speed, such conventional methods are not always suitable. The authors propose the stabilization of the bicycle using driving forces and design a controller using linear-quadratic control theory. The results of the numerical simulations show the proposed method is effective in stabilizing the bicycle. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Chihiro Nakagawa received her M.S. degree in Department of Engineering Synthesis from University of Tokyo, Japan, in 2007. She is currently a doctoral student at the department at University of Tokyo and serves as a JSPS Research Fellow. Yoshihiro Suda received his Dr. Eng. degree in Department of Engineering Synthesis from University of Tokyo, Japan, in 1987. He is currently a Professor at the Institute of Industrial Science and the Director of Chiba Experiment Station, University of Tokyo. Kimihiko Nakano received his Dr. Eng. degree in Department of Engineering Synthesis from University of Tokyo, Japan, in 2000. He is currently an Associate Professor at the Institute of Industrial Science, University of Tokyo. Shoichiro Takehara received his Dr. Eng. degree in Department of Engineering Synthesis from Sophia University, Japan, in 2004. He is currently an Assistant Professor at the Department of Mechanical Engineering at Tokyo Metropoli-tan University.     

偏载对铁路货车轴颈轴承概率寿命的影响

偏载恶化车辆服役动力学性能,增加零部件服役载荷,降低动力部件服役寿命。参考标准EN13103/EN 13104/JIS E 4501 进一步考虑惯性和结构细节效应,建立新的铁路货车及轮对的偏载简化动力学模型。依据这一模型建立包含轴颈轴承在内的铁路货车相关动力部件服役载荷确定方法。结合标准ISO 281,考虑铁路货车双列圆锥滚动轴承的产品特点及顺序轮对服役的载荷特点,建立轴承载荷和概率寿命的评估方法。通过某35.7 t轴重铁路货车轴颈轴承的偏载效应分析,揭示了偏载引起轴承谱当量载荷非线性增长、概率寿命呈非线性下降,要控制寿命下降率低于30%,服役管理的临界横向偏载程度不大于15 mm,临界纵向偏载程度不大于30 mm。     

汽车ABS的发展状况和技术趋势

装有ABS(Anti-lock Braking System)的汽车,能有效控制车轮保持在转动状态而不会抱死不转,从而提高刹车时的汽车稳定性及较差路面条件下的汽车制动性能.主要介绍了国内外ABS系统的发展状况和技术趋势.     

A numerical study for determining the ideal operating speed for a two-wheeler rider on varying terrain amplitudes

The predominant part of the Indian population generally depends on a two-wheeler for transportation needs. However, very poor road conditions and poor vehicle designs have led to development of pains in the body. The percentage of such incidents involving musculoskeletal pains is alarmingly gaining impetus in the region. Hence, an attempt has been made to analyze and obtain ideal operating conditions of the vehicle for varying terrain amplitudes of 5, 10 and 15 mm, respectively. In this work, a coupled human body and twowheeler is modeled as a lumped parameter system. The composite model is analyzed by computer program (MAT lab) for vertical vibration responses of the different body parts to vertical vibrations inputs that are sinusoidal in nature and applied to wheels of the twowheeler. The numerical analysis is carried out for a Hero Honda splendor vehicle and an average male human body weighing around 80 kilograms. The analysis successfully concludes the torso as the part of the human body that experiences maximum displacement followed by head and thorax for all the terrain amplitudes involved in the study. The study also concludes that the ideal speed of the vehicle to be maintained for the body to experience minimum vibrations is 8 Hz i.e. 49.60 km/hr.     

Kinematics of wheeled mobile robots on uneven terrain

This paper deals with the kinematic analysis of a wheeled mobile robot (WMR) moving on uneven terrain. It is known in literature that a wheeled mobile robot, with a fixed length axle and wheels modeled as thin disk, will undergo slip when it negotiates an uneven terrain. To overcome slip, variable length axle (VLA) has been proposed in literature. In this paper, we model the wheels as a torus and propose the use of a passive joint allowing a lateral degree of freedom. Furthermore, we model the mobile robot, instantaneously, as a hybrid-parallel mechanism with the wheel–ground contact described by differential equations which take into account the geometry of the wheel, the ground and the non-holonomic constraints of no slip. We present an algorithm to solve the direct and inverse kinematics problem of the hybrid-parallel mechanism involving numerical solution of a system of differential-algebraic equations. Simulation results show that the three-wheeled WMR with torus shaped wheels and passive joints can negotiate uneven terrain without slipping. Our proposed approach presents an alternative to variable length axle approach.     

一种汽车列车结构及其路径跟踪控制方法

为解决现有城市交通拥挤问题,满足城市居民生活及工作的乘车需求,综合轨道车辆单程运输量大和传统铰接车辆基础建设成本低的特点,提出一种多铰接式汽车列车。该汽车列车可灵活编组,具有大容量、单程运输效率高、因结构纵向对称且采用轮速差速运动控制、行驶灵活度高等优点。研究适用于该车型的路径跟踪控制方法,采用非时间因素的控制策略,设计汽车列车各轴轮速控制律,并构建李雅普诺夫函数,采用李雅普诺夫直接法证明路径跟踪偏差逐渐递减,即汽车列车能够沿目标路径行驶,且该方法不受车厢数量限制,可使汽车列车灵活编组。最后,建立多铰接式汽车列车路径跟踪仿真模型,分别对直线路径、圆弧路径、正弦路径进行跟踪控制,仿真结果证明采用非时间参考的跟踪控制方法,能够控制列车对多种路径跟踪。     

Using the φ-<Emphasis Type="Italic">S</Emphasis><Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> nomogram in calculating the dynamics of a braked wheel

The work deals with the investigation of parameters having effects on road holding and response of wheeled vehicles. A new procedure for evaluating forces in the tire contact area by means of the φ-S _x nomogram accounting for lateral effects on the wheel is put forth. The procedure may be used in assessment of the road holding ability of a vehicle during vehicle design, in selection of a functioning algorithm for the antilock braking systems of vehicles, and also in technical expertise on motor vehicle accidents.     

A joystick driving control algorithm with a longitudinal collision avoidance scheme for an electric vehicle

In this paper, we develop a joystick manual driving algorithm for an electric vehicle called Cycab. Cycab is developed as a public transportation vehicle, which can be driven either by a manual joystick or an automated driving mode. The vehicle uses six motors for driving four wheels, and front/rear steerings. Cycab utilizes one industrial PC with a real time Linux kernel and four Motorola MPC555 micro controllers, and a CAN network for the communication among the five processors. The developed algorithm consists of two automatic vehicle speed control algorithms for normal and emergency situations that override the driver’s joystick command and an open loop torque distribution algorithm for the traction motors. In this study, the algorithm is developed using SynDEx, which is a system level CAD software dedicated to rapid prototyping and optimizing the implementation of real-time embedded applications on distributed architectures. The experimental results verify the usefulness of the two automatic vehicle control algorithms.