制动器布置于精密齿轮传动系统输入端的效果

本文利用制动过程中能量转化守恒的原理,对制动器布置在精密齿轮传动系统输入轴和输出轴两种不同方案所需的制动力矩等情况进行了比较和研究.以ni1表示精密齿轮系统的传动比,研究表明,将制动器从输出轴移到输入轴可取得使所需制动力矩减小到原来的ni1分之一等明显效果.

中小驼峰溜放间隔制动位设置的探讨

文章论述了中小驼峰设置间隔制动的必要性和紧迫性以及间隔制动控设置的可能性.

Anti-reverse rotation startup method for sensorless brushless DC motor

In order to start up the brushless DC motor （BLDCM） without reverse rotation and smoothly switch the running state of the motor, a novel startup and smoothly switching method for a sensodess BLDCM is presented. Based on the saturation effect of the stator iron, six short voltage pulses are applied to determine the initial rotor position and the rotor can be found within 60°. After that, a series of short and long voltage pulses are used to accelerate the motor and the variation of the response current is utilized to detect the rotor position dynamically. When the motor reaches a certain speed at which the back-electromotive force （EMF） method can be applied, all the power devices are turned off and the running state of the motor is smoothly switched at the moment determined by the relationship between the terminal voltage waveform and the commutation phases. The experimental results verify the feasibility and validity of the proposed method.

空天再入飞行器最优过渡段轨道设计方法研究

针对空天再入飞行器在再入角和再入点位置给定条件下的过渡段轨道设计问题,提出了一种最优过渡段轨道的设计方法。首先,在制动点给定的条件下,由制动脉冲最大限制求得初始航迹角的区间范围,然后详细推导了由给定再入角解析计算初始航迹角的公式,进而可由初始航迹角计算所需的离轨制动脉冲和转移时间。最后用一维搜索策略对转移时间最短和燃料消耗最小的最优制动点位置进行了迭代求解。仿真表明,该算法简单易行,具有很强的实时性,对于空天再入飞行器再入时最优过渡轨道的设计具有较高的工程应用价值。

Improved Smith prediction monitoring AGC system based on feedback-assisted iterative learning control

The performance of Smith prediction monitoring automatic gauge control(AGC) system is influenced by model mismatching greatly in strip rolling process. Aiming at this problem, a feedback-assisted iterative learning control strategy, which learned unknown modeling error by using previous control information repeatedly, was introduced into Smith prediction monitoring AGC system. Firstly, conventional Smith predictor and improved Smith predictor with PI-P controller were analyzed. Secondly, on the basis of establishing of feedback-assisted iterative learning control strategy for improved Smith predictor, process control signal update law and control error were deduced, then convergence condition of this strategy was put forward and proved. Finally, after modeling the automatic position control system, the PI-P Smith prediction monitoring AGC system with feedback-assisted iterative learning control was researched through simulation. Simulation results indicate that this system remains stable during model mismatching. The robustness and response of monitoring AGC is improved by development of feedback-assisted iterative learning control strategy for PI-P Smith predictor.

Improvement of Dynamic and Steady Characteristics of Pneumatic Position Servo with Fuzzy-PI Control

This paper provided a fuzzy-PI control. It makes use of the advantages of fuzzy controller for dynamic characteristics, and the advantages of PI control for steady characteristics of pneumatic position servo. Experimental results show that positioning accuracy meets the conventional industrial needs, and prove that the fuzzy-PI controller to be correct and more effective than the usual PID controller. The control method improve the dynamic and steady characteristics of the system.

Control strategy for pneumatic rotary position servo systems based on feed forward compensation pole-placement self-tuning method

The pneumatic rotary position system, in which an electro-pneumatic proportional flow valve controled a rotary cylinder, was studied, and its mathematical model was built. The model indicated that the controlled pneumatic system had disadvantages such as inherent non-linearity and variations of system parameters with working points. In order to improve the dynamic performance of the system, feed forward compensation self-tuning pole-placement strategy was adopted to place the poles of the system in a desired position in real time, and a recursive least square method with fixed forgetting factors was also used in the parameter estimation. Experimental results show that the steady state error of the pneumatic rotary position system is within 3% and the identified system parameters can be converged in 5 s. Under different loads, the controlled system has an excellent tracking performance and robustness of anti-disturbance.

Synchronous tracking control of 6-DOF hydraulic parallel manipulator using cascade control method

The synchronous tracking control problem of a hydraulic parallel manipulator with six degrees of freedom (DOF) is complicated since the inclusion of hydraulic elements increases the order of the system.To solve this problem,cascade control method with an inner/outer-loop control structure is used,which masks the hydraulic dynamics with the inner-loop so that the designed controller takes into account of both the mechanical dynamics and the hydraulic dynamics of the manipulator.Furthermore,a cross-coupling control approach is introduced to the synchronous tracking control of the manipulator.The position synchronization error is developed by considering motion synchronization between each actuator joint and its adjacent ones based on the synchronous goal.Then,with the feedback of both position error and synchronization error,the tracking is proven to guarantee that both the position errors and synchronization errors asymptotically converge to zero.Moreover,the effectiveness of the proposed approach is verified by the experimental results performed with a 6-DOF hydraulic parallel manipulator.

Study on the all position automatic pipeline backing weld machine

As a result of the lower backing weld efficiency, the applying of automatic welding is seriously limited. So a kind of special automatic welder is designed and manufactured for backing weld. This paper introduces the character of the assembled pulse CO2 arc welding machine which has strong penetrability. It specifies the technology of controlling the parameters of all position automatic welding by computer and multi-axis controller. Moreover typical welding procedure parameters are provided. It is proved by examination that the economical and practical equipment and technology are suitable for the long-distance transmission pipeline, and it has a good foreground of spreading and applying.

城市轨道桥上无缝线路不同制动位置对桥墩台作用的影响

本文先行介绍城市轨道与桥上无缝线路的关联性,桥上无缝线路的特点和桥墩台的作用力来源。然后在现有的计算理论的基础上采用ANSYS建立线-桥-墩一体化模型,分析在标准列车荷载作用下,不同列车制动位置,桥墩台墩顶纵向位移和墩台力的大小,然后对比寻找规律得出相应结论。

在公路上如何停放拖拉机

在乡村,经常看到拖拉机驾驶员把拖拉机随便往公路上一停,就去办事,这样做很不安全。 那么,在公路上如何正确停放拖拉机呢? 首先,应减小油门,开右转向灯,将机车靠到离右边路沿30cm左右,与路边平行停放,不得歪斜。

广汽本田车系故障诊断笔记(10)

同一车系的车辆很多都是共用一个平台的,而且很多故障现象也都是大同小异的,如果可以将各种故障进行总结分析,从而归纳出车型的结构特点、故障形成机理和检测方法等,这将帮助维修人员积累维修经验、避开维修误区、改进诊断思路和完善操作流程。笔者在工作中积累了大量的故障案例,并对它们进行了整理。在此将案例进行分享,希望可以帮助读者在日常的维修过程中开拓思路,并从这些案例中找到相同故障现象与不同故障原因之间的联系,起到举一反三的作用,使人受益匪浅。

Study on Model Predictive Control to Minimize Movements in Positions Due to Thermal Expansion of Plate with Varying Generation of Heat

Precise temperature control to decrease movements in positions due to thermal expansion of work pieces is required in the manufacturing processes to achieve nanometer-order accuracy. We analytically examined the effect of a method of minimizing movements in positions on a plate with varying generation of noise-heat. Control by monitoring temperature changes caused larger movements in positions than that without control because maximum change in temperature occurred at non-monitoring positions. The best method of minimizing movements in positions due to thermal expansion of a plate with varying generation of noise-heat was model predictive control by the monitoring movements and distributed temperature changes in the control heater according to the effects of the generation of noise-heat. The maximum movement in positions was 6 nm, which was 1/4 times of that without control.

事故数据存储器

你有没有遇到过这样的客户,这种人在车出现问题时并不如实地反映在此之前他是如何开车的?如果没有遇到过,那么请读这篇有关事故数据记录器的文章。

Robotic Path Learning with Graphical User Interface

This paper describes an automated path generation method for industrial robots. Based on force control, a robotic subsystem has been developed for path automatic generation or path learning. Using a dummy tool and roughly taught guiding points around a part contour, the robot moves in position and force controlled hybrid mode, following the order of the guiding points and with contact force direction and value predefined. During the motion, robot actual position is recorded by the robot controller. After the motion, the recorded position data is used to generate a robot path program automatically. Robot lead-through may be used in the guiding point teaching. Furthermore, a GUI （graphical user interface） is developed on the teach pedant to guide through the guiding point creation and teaching, path learning, program verification and execution. The development has been incorporated into a robotic machining product option. Combination of the robot path learning function and GUI enhances the interaction between the robot and operator and drastically increases the level of robotic ease-of-use.

Robust adaptive cross-coupling position control of biaxial motion system

The stability and synchronous performance are usually hard to be improved simultaneously in the biaxial cross-coupling position motion control system.Based on analyzing the characteristics of the cross-coupling control system,a robust adaptive cross-coupling control strategy is proposed.To restrict influences of destabilizing factors and improve both of stability and synchronous performance,the strategy forces dual axes to track the same reference model using Narendra adaptive control theory.And then,a robust parameters adaptive law is proposed.The stability analysis of the proposed strategy is conducted by applying Lyapunov stability theory.Related simulations and experiments indicate that the proposed strategy can improve synchronous performance and stability simultaneously.

手扶拖拉机的安全操作

(1)手扶拖拉机在运输作业前,一般应按常规检查油和水够不够,各部分联结是否正常。 (2)在运输作业时,首先要注意安全,行驶时要严格遵守交通规则。 (3)田间作业时如田间道路条件较差,应用低挡前进。当道路泥泞和过沟埂时,要小心行驶,此时容易出现一个轮子打滑而拖拉机突然转向的现象。