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车载式高空作业平台的结构设计【7张CAD图纸和说明书】

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摘  要


本课题首先对国内外高空作业车的发展进行了概括，提出了发展中的不足，简要介绍了高空作业车的组成，然后对目前国内生产技术不完善的混合臂和伸缩臂式高空作业车的关键结构进行了设计，同时对工作斗调平技术和液压系统等关键技术进行了研究分析。重点研究了伸缩臂的结构、运动特点，并对其进行了强度校核。根据高空作业车安全性要求高，工作幅度大，结构复杂等特点，提出了工作臂、副车架以及工作斗调平机构的研究设计方法。该课题以混合臂式高空作业车为研究对象，详细阐述了伸缩臂的结构设计、变形研究；副车架结构设计、工作稳定性分析；高空作业车的工作斗调平系统的研究分析；液压系统的设计计算。课题采用积分法对伸缩臂结构进行应力分析、变形分析。最后，对研究分析结果进行了试验和验证，将试验结果和理论分析结果进行了对比，通过对比分析进一步验证了本文提出的设计方法，对于同类型高空作业车研究计算，具有一定的参考价值。


关键词 ：高空作业车；结构设计；调平系统研究；液压缸


Abstract

    This paper arranged as follows. The first part is the summary of the development of aerial working platform at home and abroad, and put forward some shortages during the development. There is a brief introduction of the component parts of the aerial working platform. This paper introduces a new design proposal of the domestic production technology of mixing arm and telescopic arm aerial working platform. Meanwhile, the analysis can also be seen in the working bucket leveling, hydraulic systems and other key technology. This paper mainly focuses on the telescopic structure, movement characteristics, and its strength check. According to the special requirements of aerial vehicles because of the high security, large in range and the complicated structure, the special design was used in the working arm, subframe and bucket leveling institutions. The subject is based on the study of mixing arm of aerial working platform. The subject describes the structural design of the telescopic boom in detail, and analysis the design of subframe structure design and the job stability. The aerial working platform bucket leveling system analysis and hydraulic syetem design are also mentioned here.the subject adopts integration method on the telescopic structure stress analysis and deformation analysis. The results of research and analysis are also compared in this part. The new design method is created through comparative analysis. And it is an useful guideline for the same type of aerial working platform.


Key words: Aerial working platform; Structure design; The research  of leveling system; The hydraulic cylinder



目  录

摘  要 III

Abstract IV

目  录 V

1 绪论 1

1.1本课题的研究内容和意义 1

1.1.1 课题研究背景 1

1.1.2 课题研究的意义 1

1.2 高空作业机械的国内外发展概况 1

1.2.1 高空作业机械的国外发展状况 1

1.2.2 高空作业机械的国内发展状况 2

1.3 高空作业车的组成 2

1.3.1 专用底盘 2

1.3.2 工作臂架 3

1.3.3 三维全旋机构 3

1.3.4 电气与液压系统 3

1.3.5 安全装置 3

1. 4 课题研究的内容 4

2伸缩臂结构分析 5

2.1 伸缩臂的结构 5

2.2 工况分析 6

2.3 伸缩臂强度计算分析 6

2.3.1 危险工况 1 计算 7

2.3.2 危险工况 2 计算 7

2.4 伸缩臂变形计算 8

2.4.1 力学模型的建立 8

2.4.2 弹性位移的计算 9

2.4.3 计算结果 12

2.5 伸缩臂强度校核 12

2.5.1 计算基本臂臂的截面尺寸 14

2.5.2对下臂进行正应力校核 15

2.6 本章小结 16

3 副车架结构及分析 17

3.1 副车架结构 17

3.2 支腿反力的计算 17

3.3 转台回转系统 21

3.4 本章小结 22

4 工作斗调平机构的研究 23

4.1 工作斗调平结构模型 23

4.2调平机构液压系统 25

4.3 本章小结 26

5液压油缸的设计计算 27

5.1 伸缩变幅油缸的结构 27

5.2 伸缩变幅油缸的设计计算 27

5.2.1 确定液压缸类型和安装方式 27

5.2.2 确定液压缸的主要性能参数和主要尺寸 27

5.3 本章小结 31

6 结论与展望 32

6.1 结论 32

6.2 展望 32

致  谢 33

参考文献 33

附  录 33


1 绪论

1.1本课题的研究内容和意义

1.1.1 课题研究背景

现如今我国经济的飞速发展以及政府对基础设施建设的力度逐渐增大，高空作业平台的需求量不断增加，市场前景非常广阔。然而由于我国对于高空作业平台的研究开发起步较晚，对其核心技术掌握的不足以及加工工艺的落后等方面的原因，使得我国高空作业产品的使用功能、安全性等方面得不到充分的质量保证。通过对目前高空作业产品市场的发展趋势和广泛的市场研究，发现国内产品具有类型单一、设计粗糙等缺陷，无法满足很多特殊施工环境的要求[l]，因此我国高空作业设备大多依赖进口。虽然国外产品功能完善、性能比较优秀，但是由于价格太高，对很多建设公司或者施工方来说成本占用比例过大，使得利润空间降低。因此，研发生产属于我国自主品牌的高性能的高空作业平台有着极其重要的经济价值和战略意义。                                                            

高空作业平台是用来运送工作人员和工作装备到指定高度进行作业的一种大型工程机械设备，并广泛用于电力、路灯、市政、园林、通信、机场、造(修)船、交通、广告、摄影等高空作业领域。国家标准GB3608．93《高处作业分级》规定：VL在坠落高度基准面2m以上(含2m)有可能坠落的高处进行作业，都称为高处作业。"因此为保障工人在高处作业的安全性，出现了越来越多的高空作业设备，然而随着科技的发展和人们对使用要求的增加，传统的高空作业设备已经无法满足人们的需求，专用高空作业平台技术在最近几十年来得以快速发展。

1.1.2 课题研究的意义

随着社会的进步和发展，人们对于产品的人性化要求越来越高，因此在产品结构设计的过程中应坚持人性化思想[2]，以人机工程学原理为指导充分分析研究产品各方面因素，提出相应的设计方案。本课题在充分研究产品性能的基础上，对高空作业平台的功能模块进行了充分的结构分析，并根据其各方面的特殊性提出了相应的设计要求，指导其结构设计，因此课题研究的意义主要体现在以下几个方面：

(1)通过本课题的研究，掌握混合臂高空作业车金属结构件的设计理论和分析方法，了解高空作业车结构件的工作规律，从而达到减轻自重、优化结构、提高可靠性的目的，为研制系列伸缩臂、混合臂高空作业车奠定良好的基础。

(2)对车载式高空作业平台进行模块划分，将其分为工作平台、操作系统、运动系统和支持系统几个部分进行分别研究，对每一部分进行充分的结构分析，结合产品的相关标准和设计原则，对其结构设计进行指导。在课题的研究过程中结合产品的使用功能，通过计算机建模，在保证实现基本功能的基础上，总结相应的外观设计理论，以指导后续系列产品的结构设计，同时对于其它机械产品的外观设计研究具有一定的理论指导意义。

1.2 高空作业机械的国内外发展概况

1.2.1 高空作业机械的国外发展状况

高空作业车发展起步较早的欧美等发达国家和地区，从20世纪20年代就开始研制，发展历史久远，生产技术也很成熟，具有生产技术水平高、作业车的作业高度大、规格齐全、结构型式丰富、功能多样等优点。总体来看，技术和市场均已很成熟，产品能够进行高空作业、抢险、救援、消防等复杂工作，作业平台的最大载荷可达500kg，最大作业高度已经超过100m，这是我国目前无法设计达到的高度，同时具有各种安全保护措施，很好的保障了工人的安全。大型产品特点是科技含量高、研制与生产周期较长、投资大、市场容量有限，但市场竞争相对较少，产品的利润相对较高。如美国Genie公司、JLG公司和法国HAULOTTE公司在高空作业平台产品都形成了系列化，与此同时，产品更新换代的周期明显缩短。这大大提高了企业在国际市场中的竞争能力和企业的抗风险能力。


内容简介：
英文原文Control strategy of the hybrid drive for vehicle mounted aerial work platformJanusz Krasucki a, Andrzej Rostkowski a, ukasz Gozdek b, Micha Barty b,a Construction Equipment Research Institute, Napoleona 2, 05-230 Kobyka, Polandb Warsaw University of Technology, Institute of Automatic Control and Robotics, Boboli 8, 02-525 Warsaw, PolandThe development process i.e. assumptions, construction, simulations and analysis of a control strategy for thehybrid drive of the vehicle mounted aerial work platform is presented in the paper. Particular attention ispaid to the development of the control system strategy ensuring appropriate energy recuperation by makinguse of energy stored in the electrochemical form. The control strategy is built up around the concept of bilevelhierarchic control system. The elevation control of the aerial work platform is assumed as the primarygoal of the control system. The secondary goal of the control system is formulated in terms of tracking andkeeping the charging level of the rechargeable electrochemical accumulator in predefined limits. A control system simulation model is developed in Matlab-Simulink environment. Exemplary results of control system simulations are shown on the example of a hydraulic power unit driving aerial work platform mounted onspecial vehicle MONTRAKS.1. IntroductionThe reduction of vehicle emission has been an objective of research for many years; partly it is forced by increasingly stringent environmental legislation. The Kyoto protocol, whichwas adopted at the COP3in December 1997, is aimed to decrease the green house gas emissions(GHG) by an average of 5% referring to 1990 levels. It came into force on February 16, 2005 following its ratification by Russia.Hybrid systems are now gaining attention as a means for reducing GHG emissions by improving fuel economy and energy eficiency.Market for hybrid driven vehicles is growing up dynamically sincemany years. Contemporary, eleven large car manufacturers use to deliver or to intensively develop hybrid driven vehicles. Even that is mainly focusing on passenger cars segment, it should be stressed that the remarkable effort is undertaken to implement hybrid drives in the trucks, delivery vans and buses 1,2.WestStart-CALSTART 3, an advanced transportation technologies consortium, supported by U.S. Army National Automotive Center(NAC), organized the pilot program as part of its Hybrid Truck Users Forum (HTUF) program, to speed up and to assist hybrid commercialization. According to the forecasts elaborated by CALSTART,the hybrid driven trucks market share will grow reaching ca 9% in 2010 and near 18.5% in 2020.Still heavy duty machines and special purpose vehicles are the object of possible implementation for hybrid drive solution. However there are some doubts, if that application is economically feasible.Considering passenger cars,in respect of environmental regulations,important role plays the “effect of the scale”. In case of heavy duty machines, aerial work platforms, pick and carry mobile cranes or special vehicles with lift equipment, the application of hybrid solution is driven with operating constrains and application.For many cases, working conditions for that class of machinerystrongly limits or even eliminates the application of combustion engines. In particular that is case of closed space areas such as factory shops, warehouses, intrinsically safe zones, etc. Here the implementation of diesel-electric drives could considerably extend possible use of that kind of equipment. Very unique and on the other side common area of services is municipal services and works used to be processed during night in the highly populated zones (street sprayer-sweepers,garbage trucks, tramway traction networks service vehicles, etc.). It is often reported by municipalities, that the issue to be solved for that services is the level of noise generated by diesel engine.An example on how to meet the ever-increasing regulations controlling environmental conditions during indoor lifting operations is the battery powered cranes line designed by Valla Corporation 4,which recently extended the offer for hybrid solution. Another example is a hybrid system investigated by Eaton Corporation 5,6for medium trucks with optional aerial work platform equipment.Eaton began commercializing its medium-duty hybrid system in August 2007 in a wide variety of applications such a: telecommunications and municipality, city delivery, refuse, city transit bus, pick andcarry and so on.A hybrid vehicle is defined as one that has more than one source of power. Several different types of hybrid solutions have beenconsidered in the past and are still undergoing extensive research, Fig. 1. Special purpose vehicle MONTRAKS 3PS.such as Hybrid Electric Vehicles (HEVs) 1, which use a motor/generator and battery packs (or other electrical storage devices) and mechanical hybrids which use flywheels to store energy. Hybrid Hydraulic Vehicles (HHVs) 2, which store kinetic energy captured during braking events and store it in hydro-pneumatic accumulators and return energy to driveline during vehicle acceleration. Various different structures of hybrid drives (serial and parallel) have been developed. 7,8The hybrid electric system maintains conventional drive train architecture while adding the ability to enhance engine power withelectrical one.One feature of this system is its ability to recover energy normally lost during braking and store the energy in batteries. The stored energy is used to improve fuel economy and vehicle performance for a given speed or used to operate the vehicle with electric power only.The control of hybrid power trains is more complicated than the control of ICE only power train. First, one needs to determine the optimal operating mode among five possible modes (motor only,engine only, power assist, recharge, and regenerative). Furthermore,when the power assist mode or the recharge mode is selected, the enginepower and motor power needs to be selected to achieve optimal fuel economy, battery charge balance, and operability. With the increased power train complexity and the need to achieve multiple objectives, most often a two-level control architecture is adopted 5.Fig. 2. Structure of the hybrid drive unit. Notion: x piston stem displacement, v piston stem velocity, p1 under piston pressure, R1 switching signal of valve (8), p2 supply pressure, R2 switching signal of valve (7), n1 EM rotational speed, U battery voltage, I battery current, n2 ICE rotational speed, OUT setpoint of electric motor controller.Fig. 3. Structure of the control system. Notion: SP_xp Setpoint of the AWP position. PV_xp Actual value of the AWP position. e_xp AWP position control error. SP_vp Setpoint of the lifting or lower velocity of the AWP. PV_vp Actual value of the AWP velocity. SP_SOC Setpoint of the battery SOC. PV_SOC Actual value of battery SOC. PV_P1 Actual value of the pressure p1. PV_P2 Actual value of the pressure p2. OUT1, OUT2 Outputs of PID controllers.The analysis of power control systems optimizing: power efficiency factors, fuel consumption and emissions has been given in3,9,10. Investigations have been mainly focused on the possibility of kinetic energy recuperation in the phase of vehicle braking.In this paper, the design of a power management control system isdescribed for a hybrid drive system of special purpose vehicle with hydraulic aerial work platform (AWP) equipment. For that type of vehicles (stop-and-go duty cycles) the potential energy of the load being handled with AWP should be seriously considered as recyclable 11,12.The major advantage of the proposed hybrid drive over othersolutions is a simple drive architecture. It differs from known solutions, thosewidely used in personal cars. The classic approach (personal cars) needs full redesign of power transmission system. The innovative approach for the special purpose vehicles requires only extension of classic ICE drive with extension unit. Extension unit is composed of electricmotor coupledwith hydraulic pump/motor. That solution allows to differentiate the power flowbetween the thermal and electrical path with help of hydraulic subsystem. However, even that solution is not straightforward from the point of view of power flow, it demands for advanced control system strategies.Two-layer hierarchical control system architecture is considered in this paper. A lower control level is built by application of local classic proportional-integral-derivative (PID) controllers. A higher control level is developed around a fuzzy logic controller (FLC) with the intention of dynamically setting out control rules for lower level local controllers2. Characteristics of the target systemA specialized automotive vehicle MONTRAKS (Fig. 1) is intended for repairing and maintenance of tram and trolley-bus overhead wire system, assembling and disassembling of rail track sections and is exploited by the municipal communication services.Such types of vehicles are usually designed on the bases of regular trucks undercarriage equipped with appropriate working accessories. The equipment is built up around the aerial work platform (AWP) (1) embedded at the end of the boom (2) driven by the set of two hydraulic cylinders and hydraulic swing motor (3).Besides a standard road running on the tires, the major feature of these vehicles is the possibility to move on rail run. That is achieved with additional set of rail wheels (4) which are driven with low speed hydraulic motors.As often as not, maintenance and repairing of the traction networks take place throughout the night, and these are time consuming operations. For the period of the time that repair work is carried out, the vehicle is parked; instead of the engine is continuously running and driving the hydraulic pump which is used to supply oil to the hydraulic equipment. In this phase of duty cycle, a power demand from the working equipment is low does not exceed 3% value of engine rated power 2, due to that the diesel operation point approaches the regions of its low efficiency and significant emissions. Simultaneously, the diesel generates particularly bothersome noise.Disadvantages mentioned above may be eliminated for instance by introducing an additional electric motor (EM) powered by an electrochemical battery pack. In this case, the ICE will delivermechanical power when the vehicle moves from/to its operation area. While parking the vehicles power demand from the working equipment will be balanced from the EM and optionally from the ICE.The structure of discussed hybrid drive is shown in Fig. 2Energy for the motor is supplied from a set of electrochemicalaccumulators (5). The primary power source of the equipment drive unit is the EM. Motor traction parameters are controlled by the pulse width modulator (6). It is possible to reverse the motors operation into generator mode. The EM runs the hydraulic pump (3) supplying the hydraulic actuation system. The ICE, running in the appropriate chosen operating point, drives the second hydraulic pump (2).Hydraulic oil flows frompumps (2) and (3) are added together in the common supply line. Hydraulic switching valves (7) and (8) redirect the oil flow in the main supply line either to the tank via overflow valve or to the under piston chamber of the hydraulic cylinder (9).The piston stemof the cylinder (9) controls the elevation angle of the boom (10) and indirectly the position of AWP (11). It is obvious that the control of the cylinder (9) influences the potential energy of load Q while the platform is lifting or lowering.The following phases are to be distinguished in the duty cycle of thehybrid drive unit: SPL phase lifting of the AWP, SPD phase lower of the AWP, SPP phase parking of the AWP.In SPL phase, as a result of movements of the cylinders (9) piston and appropriate boom lifting movements, the addition or differentiation of oil flows from pumps (2) and (3) takes place. In case of subtraction of flows, one part of the pump flow (2) is directed to the main supply line and the reminder part of flow drives the pump (3) switched into motor mode. In SPD phase, the direction of oil flow in the main hydraulic supply line changes, oil runs the pump (3), and the mechanically coupled electric motor (4). In both phases it is possible to supply cylinder (9) by the oil delivered by the pump (3) driven by electric motor (4). Charging a battery (5) occurs in the SPP phase. In this phase, the AWP is fixed, and the pump (3) is driven by oil provided by the pump (2).Fig. 4. Membership functions of the AWP position control error.3. Control strategyIn general, the main objective of the power control strategy is to operate the hybrid drive with possible high energy efficiency and low emissions while maintaining specified vehicle performance 13.Maximal use of electric power is the main task of the hybrid drive control system. This corresponds with specific requirements for noise level and economic operation of MONTRAKS vehicle.This can be achieved by applying of the proposed power control strategy. This strategy is based on operation of AWP velocity closed to required trajectory and effectively capturing of the regenerative energy by controlling the state of charge (SOC) of a battery. As it is only possible,the electric drive should be used in SPL and SPD phases of duty cycle.SOC is the ratio of present charge of a battery to the maximum charge that can be possibly stored in the battery and in time instantt=T may be expressed as:;01()()TSOCTitdQwhere:Q(t0)=Qmax maximal capacity of the battery, SOC(t0)=1,i(t) battery charging or recharging current.Meanwhile, the SOC of a battery should be controlled between a minimum SOC and a maximum SOC to obtain regenerative braking energy effectively with the least amount lost and stress on the battery.The minimum and maximum SOC levels are determined according tothe ability of a battery to absorb regenerative energy and to restart vehicle systems. In general, the larger the difference between the minimum SOC level and the maximum SOC level, the more regenerative energy a battery can effectively absorb. However, the larger span of operating SOC levels may reduce the batterys life, which is affected by the depth of discharge. Hence, the SOC levels should be appropriately determined between optimal minimum and maximum levels SOCmin, SOCmax. Considering the battery charging and discharging efficiency, the SOC range is set to 0.3, 0.8 in this paper. The power flow distribution between engine and electric motor may be defined through degree of hybridization (DOH) of the drive:;(0,1)motICEPDOHDOHwhere: PICE engine power, Pmot motor power.The combined power management/design optimization problem can be written as follows:()()in()isptvtetXmi maxSOCSwhere:XSP(t) 2 desired AWP trajectoryXPV(t) 2 actual AWP trajectory.A structure of the proposed control system for this purpose is given in Fig. 3.Fig. 3 shows the structure of the control system. The control system consists of two loops: control of the AWP position and velocity, control of the SOC of battery pack.Each loop may control electric motor controller. Control signals are governed by the logic unit. It is aimed to provide smooth switching of control signal for appropriate time instants. Control system for AWP positioning and velocity control has a cascade structure. Fuzzy controller processes the velocity of the AWP. It is calculated from the real and desired platform displacement. Velocity signal from the auxiliary controller SP_vp is fed as the reference to the classic PID controller and it is compared with actual velocity of the platform PV_sp. The second control loop keeps the SOC of battery in predefined limits. This loop consists of PID controller and logic unit. PID unit controls the level of charge of the battery through continuous adjustment the hydraulic valves positioning.Fig. 5. Membership functions of the AWP velocity.3.1. AWP position controllerA controller of the AWP has been developed based on the cascade of classic PID controller and FLC. The FLC has been chosen because of its suitability for control of nonlinear, multiple-domain, and timevarying plant with multiple uncertainties 3. This controller has two inputs: a control error of the AWP postion (SP_xpPV_xp), and acurrent velocity of the AWP (PV_vp). The FLC calculates setpoint value of the AWP velocity SP_vp for the PID controller of the electric motor.The FLC 14 consists of three basic blocks: fuzzyfication, inference and defuzzyfication. Inputs of the controller are fuzzyfied in the fuzzyfication block. In fact, fuzzification maps the space of crisp values onto the space of fuzzy ones. In this process, each crisp sample of each input signal is transformed into the set of numbers interpreted as the membership degrees of this samples to the appropriate fuzzy values (fuzzy sets). Fuzzyfied inputs are fed to an inference machine. The inference machine makes fuzzy outputs based on: fuzzy inputs, fuzzy logic rules and knowledge embedded in the rule base (Fig. 6). The rule base is created based on the appropriate knowledge or by means of learning from data or is acquired from real or simulation experiments. Fuzzy output from the inference machine is transformed into the crisp value by means of defuzzyfication procedure. Exclusively the triangle and trapezoidal membership functions have been used in the process of fuzzyfication. In fuzzy AWP velocity controller each input was fuzzyfied by means of seven membership functions (see Figs. 4 and 5).The rule base applied for the inference process is depicted in Fig. 6. Rule base is assumed as the set of quantitative knowledge. A total of 49 rules have been formulated for the FLC. For the clarity, the rule base is displayed in t
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