开发出一种基于试重标定法原理的新型软支撑动平衡机.以MSP430系列混合数字处理器为数据采集单元,以嵌入式工控机为主控单元,以转速和MEMS (Micro-Electro-Mechanical System)三轴加速度传感器为传感单元,自主开发信号调理电路板、数据采集处理程序和上位机应用软件.该系统可实现传动轴单、多面的不平衡量大小及角度的精确测定,以便进行配平,并具有较好的人机界面.

对于具有运动关联随机振动(MRRV)特性的设备,需将宏观运动与高频随机振动联合研究.开发出一种基于ARM(Advanced RISC Machine)技术的运动关联随机过程数据采集系统.以ARM11芯片为主控单元,以微机电系统(MEMS)姿态传感器、语音传感器及温度传感器为传感单元,自主开发信号调理电路板、电源管理板、ARM系统板、基于Windows CE的数据采集处理程序以及上位机信号分析与故障预警软件.该系统可实时采集传输该类设备运行过程的三轴运动振动混合加速度、三轴角速度、应力应变及辅助语音信号等,为运动关联振动分析提供数据支持.

By establishing themulti-body dynamical model of roller coastersvia ADAMSTM,such motion parameters as driving speed,normal acceleration and postural angle are first obtained.Then,the vibration model of one fourthbody,along with vibrationequation,is attained.Finally,the random vibrationsignals of healthy and wheel broken conditions are simulate using SimulinkTM.Therefore,the simulation results and analysis methods set a reference to design,safety evaluation,fault diagnosis and precaution for roller coasters.

在国外工程施工作业中国产平地机常出现零部件提前失效导致使用寿命不足的问题,对比平地机的国内外工况,根据使用时间历程,预估九级载荷谱.载荷谱的分析和计算结果表明:国外工况下平地机的平均载荷相对更大.基于疲劳曲线方程对平地机工作装置和传动系统主要零部件进行寿命预估,提出设计强化工作装置强度等措施以解决工作装置的失效问题,并对传动系统进行参数再匹配,实现延长平地机传动系统的使用寿命.

The hydraulic system of screw distributor plays an important role in asphalt paver. It belongs to the speed-regulating system of pump controlled motor. The motor speed and direction of rotation can be controlled by variable delivery pump. Thus the transferring speed of bituminous mixture can be adjusted. The mathematical model of the system is presented, and dynamical characteristics are analyzed. Simulation results indicate that the system is suitable to screw distributor and has high operating efficiency. By changing the angle of swashplate, the rotating speed of motor can be adjusted proportionally. The undamped natural frequency of the system is lower for two reasons. One reason is only one line controlled by the trapped oil spring rate. The other reason is larger volume of pump.

A new iteration method based on geometry to solve the inverse kinematics for the boom system of truck mounted concrete pump, which is difficult to real-time control since its degrees of freedom are multiple-redundant, is presented. This method uses a variable-step size technique to approach the solution of the inverse kinematics, and uses geometry to determine how much angles of joint to change and its direction. Comparing with the traditional methods, this method is more suitable for real-time control of truck mounted concrete pump boom system without calculating the inverse matrix of jacobian. By the method the movement of boom will be safer and more stable when pumping concrete. Simulation results show that the new method has a fast convergence speed and good stability.

Displacement control unit is an important part of hydraulic system for screw distributor. By adjusting the angle of swashplate, it can change the flow rate of pump and rotating speed of screw distributor. The rotating speed of screw distributor has influence on quality of road. The mathematical model of displacement control unit is presented. Its dynamical characteristics are analyzed. The mathematical model includes a reset spring gradient. The reset spring gradient is much smaller than the hydraulic spring rate, the effect of the reset spring gradient can be neglected. So an inertial element can be substituted by an integration element.

Different from anti-drag system (ADS), front jacking (FJ) and endless self-advancing (ESA), a new synchronously jacking hydraulic system is presented. Under the condition of non-artificial ground freezing, it can fulfill jacking operation before excavating operation. Three-level structure of the system improves reliability. A "double-object synchronization" control scheme of displacement synchronization and even-pressure enables groups of hydraulic cylinders to control the jacking speed and posture of box. The system is saving-energy. The features of antiinterferencing hardware circuits are presented also. And the system is applied successfully to Beihong Vehicular Undercrossing Tunnel project in Shanghai, China. The tunnel is 126.00 m long, 34.20 m wide, and 7.85 m high. And the project itself is also the one constructed with the largest cross-section under shallow saturated soft clay formation in China.

Part of the Central Ring Fast Autoroad in Shanghai, Beihong Vehicular Undercrossing Tunnel is a two-way, eight-lane vehicular tunnel of 126-m long, 34.2-m wide, and 7.85-m high. An electrohydraulic control system for synchronously jacked box tunneling was developed in the project. Estimation of jacking force is essential prerequisite of design of electrohydraulic system. Volume speed-regulating hydraulic circuit rather than throttle circuit was used to adjust flow rate, and the rotating speed of driving motor of main pump is controlled by variable voltage variable frequency (VVVF) technology. Three-level structure of control system was employed. A “double-object synchronization” control scheme enables 112 cylinders to coordinate the extending action, and automatically achieve synchronous motion and posture control of box and uniform load distribution to each pump unit. Differences are controlled within ±40mm during the whole jacking process.

Most of hydraulic strand jacks cannot fulfill consecutive motion of lifting or lowering. Non-consecutive motion will generate additional inertial force that probably changes initial stress distribution of large and heavy structure in addition to be time-consuming. To solve the problem, an electrohydraulic system and corresponding strand jack were developed. The new strand jack uses two lifting cylinders to alternate lifting (lowering). The velocity difference between the two lifting cylinders is a key parameter to achieve smooth transferring-load and consecutive motion. The working principle of lifting is different from that of lowering. Electrohydraulic system is presented. To get the least values of velocity difference and the transferring-load stroke, the method of double-objective optimum is applied. Test results verify that the strand jack and electrohydraulic system can fulfill consecutive motion of lifting and lowering.

将案例法引入"自动控制原理"课程的教学中,介绍了7个具体实例,采用由浅入深的方式,将案例法分为四个阶段.案例法在激发学生学习积极性和实际应用能力等方面具有较好的效果.

The concept of balanced-maintenance is derived from the recognition of the deficiency of the present maintenance system and the repair program.What determines the balance-maintenance program period has been attributed to the repetitive feature of the vehicle component failures,like the car doors. The key technology about the balance-maintenance repair policy has been discussed,which,as the paper holds,will reduce the component failures and enhance the reliability of the vehicle operation.

建立平地机用分流阀的动态数学模型,并对其进行仿真计算.仿真结果表明原分流阀存在动态特性的缺陷,据此对其结构加以改造,改造后的分流阀动态特性得到改善.

结合我国200 km/h电动车组制动系统的研制,阐述了微机控制直通电空制动系统的特点与设计方案,通过对系统及主要部件的试验研究,表明方案已达到了设计要求.