1. 研究目的与意义（文献综述）

by the end of 2016, a total of 30 cities in the chinese mainland had opened urban rail transit lines with a total length of operation exceeding 4,000 km. during the “13th five-year plan” period, urban rail transit will have a larger development trend. urban rail transit mainly solves traffic congestion and environmental problems caused by the rapid growth of urban population, its construction and operation are mainly in cities and suburbs. in the construction of urban rail transit lines, many large-scale machineries used in the national railway cannot play its role. in addition, after the line is put into operation, both underground and above-ground lines are located in the city, and their maintenance is also in the city. therefore, the need for flexible and small machine is needed to meet this construction. the rail vehicle is a professional equipment for solving road operation and track operations.

more than 85% of the construction of the new railway contact network project in china is working at high-altitude. currently, the high-altitude work vehicles on the market are mainly featured by wheeled walking and single-workbench work. they are only suitable for working at simple high-altitude such as single-person or two-person installation and maintenance. a single device cannot participate in the multi-station, multi-point simultaneous installation or debugging of larger workpieces. at the same time, wheeled aerial work vehicles and rail aerial work vehicles cannot walk and operate on the railway and highway at the same time, resulting in the construction of the new railway contact network. due to the constraints of construction period and the construction schedule before the station, it is impossible to determine whether the track is laid and wheeled walking vehicles and rail vehicles need to be continuously scheduled. at the same time, due to the limitation of the construction site, a large number of aerial work equipment enters the site at the same time. the construction condition is complex and the management is difficult. at present, in the traditional high-altitude construction in china, the original construction methods and technologies such as artificial climbing, heightening and augmenting artificial ladder trucks or long ladder and frame are adopted. because the ladder car itself does not carry the power, the construction needs more than 8 people for a group to lift and move the ladder car, hence, the operation is inconvenient and labor intensive. the operation of ladder car mainly relies on manual pushing and supporting to prevent the ladder car from capsizing which has serious safety risks. therefore, the research and development of practical roadway and railway-station aerial work vehicle has become a necessity. the dual-purpose high-altitude work vehicle is widely used in the construction, maintenance and repair of railway contact networks, as well as the high-altitude work in the fields of subway, light rail, tram and highways.

the biggest characteristic of roadway and railway-station aerial work vehicle is that it can adapt to a wide range of working conditions. this type of equipment has two independent walking systems, which can meet the requirements of driving on highway and railway at the same time and adapt to the horizontal operation and slope operation under the two working conditions of highway and railway. at the same time, the supporting leg can act as the stabilizing supporting leg of the whole machine to ensure the balance of the whole machine in the non-track operation. at the same time, it has a strong off-road performance, free across the railway crossing bed, as well as more rugged road surface.

2. 研究的基本内容与方案

basic contents include:

[1]. to investigate the current application technology status and main problems of roadway and rail dual-purpose aerial work vehicle.

[2]. the overall layout and design of light-duty railway-roadway aerial work vehicle.

3. 研究计划与安排

[1]. (week 1) project conception, literature search, and the completion of the proposal report.

[2]. (2-3 weeks) off-campus internship, off-campus data collection, foreign language translation, data collection.

[3]. (week 4-6) overall layout design and calculation and overall layout sketch drawing.

4. 参考文献（12篇以上）

qiao weigao. “structure and design of special purpose vehicle” [m]. beijing: peking university press, 2010.

this book describes the structure and design of seven categories of special-purpose vehicles and car trains including van, tank car, dump truck, crane lift car, warehouse grate car, special structure car and car train. on the basis of introducing the structure characteristics, working principle and parameters of the whole vehicle, the design principle, calculation method and selection of main technical parameters of the special working device and typical parts are analyzed emphatically.

yu zhisheng, xia qunsheng. “automobile theory” [m]. beijing: china machine press, 2009.3.