飞机发动机硬式操纵系统非线性传动优化设计

采用特殊机构实现非线性传动在机械式飞行操纵系统中已有应用,通过对传动要求的近似拟合,可以完成对机构设计参数求解;但采用该方法设计机构不能精确满足传动约束要求,在机械式飞机发动机操纵系统中尚无应用。根据飞机发动机硬式操纵系统的工作特点,采用五杆式机构替代四连杆机构实现非线性传动;通过五杆式机构设计参数影响机制分析,将机构设计参数分类为优化决策变量和传动特性控制变量,并基于此建立了机构求解方法和优化设计方法,实现了对机构传动特性控制变量直接求解,保证了机构传动特性能够精确满足约束要求。引入最大传动比和机构磨损因数作为目标函数开展机构优化,能够提升系统性能和使用寿命。通过某型发动机操纵系统设计实例和地面试验验证表明,该方法合理可行,具有工程实用价值。

一种非线性传动机构的模糊补偿

在地平式望远镜机架的一种俯仰跟踪控制传动链中,其俯仰角度与电机转动角度之间存在非线性关系 ,用经典PID控制方法很难使系统获得很好的动静态性能。将模糊控制和经典PID控制相结合 ,根据参考模型和实际模型的误差动态调整控制器参数 。

齿轮齿条非线性传动系统研究

针对传统凸轮机构无法将直线运动可靠转换为可控非匀速整周回转运动的问题,提出了一种齿轮齿条非线性传动系统。在齿轮齿条非线性传动系统中,将齿条分度线制为曲线,利用直线导轨或直线轴承与万向联轴器导出齿轮的回转运动,此时齿轮为从动件。齿轮也可作为主动件,输出非线性直线移动,由此实现双向传动。

一种非线性传动机构的模糊补偿

世界上许多概念都是模糊的,但人们却能根据这些概念进行推理,得出明确的结论。初看起来,模糊似乎不是一件好事,事实上却相反,它可用较少的代码传递足够的信息,并能对复杂事物做出高效率的判断和处理。模糊控制是用模糊逻辑实现精确控制的一项技术。模糊控制包括输入级、处理级和输出级3个过程。输入级将输入数据转变为模糊数据,称为模糊化;处理级用模糊数据及模糊逻辑规则推理求解;输出级将模糊数据变成精确数据输出以进行控制,称为逆模糊化。模糊控制的优点是,当过程的数学模型不存在或虽存在但编码十分困难时,可考虑采用模糊控制;采用不太昂贵的传感器和低性能的处理器,就能达到相当好的控制性能;可应用于环境噪声水平高的场合;能巧妙地综合直觉经验,在具有纯滞后、大惯量、参数漂移大的非线性不确定分布参数系统中,实现较满意的控制。缺点是,精度不高,容易产生振荡,适应能力有限。当前,模糊控制作为一种新型控制技术,正处于蓬勃发展时期,已开发和研制的控制器有3类:自调整型模糊控制器、混合型模糊控制器和自学习型模糊控制器。本期选登的4篇论文,一篇属自调整型,三篇为混合型。

内镜柔性器械腱鞘传动模型及实验研究

目的建立内镜柔性器械腱鞘系统的推力传动模型,研究影响传动效率的关键因素。方法建立腱鞘系统在器械推送作用下力和位移的传动模型并进行仿真计算;搭建腱鞘系统传动测试的实验平台以验证模型的准确性,研究传动速度、腱鞘直径比、弯曲半径等对传动效率的影响。结果腱鞘传动过程中存在显著的非线性传递现象,传动模型仿真与实验结果基本符合;传动速度、腱鞘直径比、弯曲半径均对内镜柔性器械的推力传动有较大影响,对位移传动的影响相对小一些。结论该模型可用于内镜柔性器械中腱鞘系统推力传动的计算,提供给医生器械工作末端的力反馈,以保证器械的安全操作和提高手术效果;在内镜柔性器械的精准控制中需要综合考虑传动速度、腱鞘传动比、弯曲半径等对运动传递的影响。

高速无菌砖式包装容量调整系统动力学分析及机构设计

采用凸轮连杆组合机构设计出了应用于高速无菌砖式包装机的容量调整装置。对此凸轮连杆组合机构作了线性传动分析。该机构中的凸轮由摆动滚子、移动凸轮段和摆动滚子、从动盘形凸轮段构成,对盘状凸轮段和移动凸轮段的廓线做了研究,并给出了凸轮廓线方程及压力角和曲率半径的计算公式。

轮边主减速器二级齿轮组齿轮的啮合优化分析

使用静力学分析与遗传算法相结合的方式对减速器进行设计、优化时,对于在传动中承受大扭矩的轮边减速器,没有考虑到因加速度引起的惯性力。针对电驱动救援车轮边减速器原主减速器二级齿轮组的强度偏弱问题,对主减速器二级齿轮组齿轮进行了设计、优化分析,解决了原减速器二级齿轮组强度偏弱问题。首先,依据轮边主减速器基本数据,进行了主减速器的三维建模设计,然后对所设计模型添加了相应的约束条件,对其进行了瞬态动力学仿真分析,发现了二级齿轮组存在强度偏弱问题;然后,提出了使用蒙特卡洛算法与宏观、微观优化相互配合使用的方法,对二级齿轮参数(即螺旋角、压力角、法面模数)进行了数据优化处理;最后,使用所获得的优化数据对减速器二级齿轮组进行了重新建模和仿真分析,由仿真分析结果判定了优化的可靠性。研究结果表明:进行优化后,减速器二级齿轮组齿轮的线性传动误差降低了59.38%,齿根处最大应力值降低了14.3%;同时,齿面接触印痕、齿面接触载荷、齿根最大接触应力均得到了优化,提高了齿轮的整体使用寿命。

5号馆B03 COMAU公司高速机床URANE25

Uranc机床在欧洲、中国、北美和中东生产，产量500台以上．在具有线性传动技术的高速加工领域中，这种机床已确立了其领先的地位。

Stability of Oil Film and Output Speed of Hydroviscous Drive Affected by the Pressure of Control Oil

Based on the theories of hydraulics and nonlinear control system, the model of hydroviscous drive (HVD) was established, the influences of small ripple of control oil pressure on the output speed of HVD and the stability of oil film between friction disks were analyzed. The conclusion presents that when the frequency of the control oil's pressure ripple is higher than 60?Hz and the peak is less than 0 05?MPa, HVD can work stably. The result is useful for studying the application of frequency conversion technology in regulation of control oil pressure.

驱动装置的选择性替代方案

多年以来,气动和液压系统成功地在各种不同的情况下得到了应用。但由于在健康和安全方面的规定越来越严格,而且要求更进一步提高工艺技术及效率,这些系统的缺点就越来越明显地暴露出来。现在,机电一体化驱动装置越来越多地取代液压和气动传动装置。

线性空程传动耦合自适应机器人手研制

传统耦合自适应手指采用并联的两套传动机构实现先耦合后自适应的复合抓取模式,存在机构复杂、内耗大和弹簧选型困难等不足。针对此问题,设计了一种新的耦合自适应欠驱动手指机构——COSA-LET手指。COSA-LET手指包括多个齿条、双拨杆、双限位凸块和双弹簧等,由一个电机和串联传动机构驱动两个关节。COSA-LET手指利用反向双齿条和带弹簧及凸块限位的齿轮实现耦合联动功能,利用关节轴弹簧将电机动力分解到两个关节轴,通过双拨杆线性空程传动的延时拨动效应解决了自适应阶段的解耦问题。手指抓取受力分析和实验结果表明,所研制的带有3个COSA-LET手指的COSA-LET机器人手实现了耦合与自适应复合抓取功能,能够根据被抓取物体的大小、形状和位置,在耦合与自适应之间自主切换抓取模式。

Newton chaos iteration method and its application to mechanism kinematics synthesis

Many questions in natural science and engineering can be transformed into nonlinear equations. Newton iteration method is an important technique to one dimensional and multidimensional variables and iteration itself is very sensitive to initial guess point. This sensitive area is the Julia set of nonlinear discrete dynamic system which Newton iteration method forms. The Julia set, which is the boundaries of basins of attractions, displays the intricate fractal structures and chaos phenomena. By constructing repulsion two-cycle point function and making use of inverse image iteration method, a method to find Julia set point was introduced. For the first time, a new method to find all solutions was proposed based on utilizing sensitive fractal areas to locate the Julia set points to find all solutions of the nonlinear questions. The developed technique used an important feature of fractals to preserve shape of basins of attraction on infinitely small scales. The numerical examples in linkage synthesis showed that the method was effective and correct.

Sliding Mode Control Approach for Electrically Controllable Clutch of AMT Based on the Feedback Linearization

A sliding mode control approach based on the feedback linearization is proposed for the electrically controllable clutch of AMT vehicles. The nonlinear dynamic model for the hydraulic actuator associated with clutch is established. By means of the exact feedback linearization procedure of differential geometry, an equivalent, fully controllable and linear model is derived via a homomorphic transformation for the AMT clutch system.Furthermore, a sliding mode control is introduced to improve robustness. The tracking tests are performed using the sliding mode control on a Santana LX passenger car, and the experimental results prove that this nonlinear controller is of fine robustness and high degree of tracking accuracy.

Nonlinear identification and characterization of structural joints based on vibration transmissibility

In order to investigate the nonlinear characteristics of structural joint,the experimental setup with a jointed mass system is established for dynamic characterization analysis and vibration prediction,and a corresponding nonlinearity identification method is studied.First,the sine-sweep vibration test with different baseexcitation levels areapplied to the structural joint system to study the dominant modal of mass rigid motion.Then,based on t e harmonic balance method principle,t e measured vibration transmissibilities a e utilized for nonlinearity identification using different excitation levels.Experimental results show that nonlinear spring and damping force can be represented by a polynomial order approximation.The identified nonlinear stiffness and damping force can predict the system’s response,and they can reveal t e shifts of resonant frequency or damping due to discontinuity of contact mechanisms within a certain range.

Research on the soft start-up performance of hydro-viscous drive

The principle and structure of hydro-viscous drive(HVD) set is introduced. Through theoretical analysis of the HVD set start-up steadiness, the conclusions were obtained that the non-linearity of the pressure performance curve and dynamic pressure instability of the pilot-operated electro-hydraulic pressure relief valve, which is used for the HVD speed regulating purpose and usually works within micro flow-rate and low oil pressure state, are the main causes of the poor start-up steadiness. So a special speed regulating valve for HVD set is developed, with which the start-up steadiness of HVD set is much improved.

A Study on the Dynamic Performance of Hydroviscous Driyes

Gives a dynamic mathematical model of a typical type of multiple discs hydroviscous drive device which has been proved to be correct through tests.Utilizing the method of root-locus analysis the dynamic performance of this device is studied according to the model.Theoretical analysis and test re- suits show that the dynamic performance of the object of study can be greatly improved by speed negative feedback.

Fluid Flow and Heat Transfer Characteristic of Outer and Inner Half Coil Jackets

The physical models of the outer and inner half coil jackets were simplified to two types of coiled ducts.The mathematic models of incompressible fluid at the condition of laminar flow and heat transfer in the two types of jackets for cooling process reactor were set up and solved by the semi-implicit method for pressure linked equa-tions consistent （SIMPLEC） algorithm based on a control volume method.The flow and temperature fields were given and the effects of Dean and Prandtl numbers on flow and heat transfer were studied.The results show that flow in the inner half coil jacket is found to exhibit transition of secondary flow pattern from two vortices to four vortices when the Dean number increases,but that in the outer half coil jacket is not found.The critical Dean num-ber is about 96.The inner half coil jacket has stronger heat transfer ability than the outer half coil jacket and this superiority is more evident with larger Prandtl number.However,as the Dean number is greater than 105,the flow resistance enhances more severely in the inner jacket than the outer jacket.For both jackets,the centers of the heated wall are the poorest for heat transfer.

Integral sliding mode control for flexible ball screw drives with matched and mismatched uncertainties and disturbances

The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.