摘 要

本文写的是一辆无人驾驶纯电动公交车的总体设计，该客车车长8.2米。

通过查阅大量的文献，然后从驱动电机的选择，电池的选择着手，根据设计要求，计算最后得出满足行驶要求的电机和电池。在选好电机和电池后，与燃油汽车不同，综合电动汽车的结构设计需要对汽车的传动系统，转向系统，制动系统进行一一分析后再设计。在我所设计的这辆无人驾驶电动公交车上，它的传动系所用的是二挡减速器，根据要求选择合适的最高传动比、最小传动比、以及主减速比。然后通过最高车速以及最大爬坡度来校核所选择的传动比。该辆公交车环境感知系统选择一个三维激光雷达布置在车顶，两个二维毫米波雷达分别布置在车头和车尾、三个相机两个放在车头一个放在车尾和四十个超声波传感器，车头四个车尾四个车身每隔半米一个。最后在这些的基础上计算所得数据，对汽车进行总布置设计。

关键词：无人驾驶纯电动公交车; 总体设计; 电机; 电池; 底盘布置

Abstract

This paper writes the overall design of an autonomous intelligent pure electric bus, whose length is 8.2 meters.

By consulting a large number of literatures, and then starting from choosing drive motor and battery, and then design the motor and battery that meet the driving requirements. It's different from a fuel car, after choosing the motor and the battery, The structural design of integrated electric vehicle needs to analyze the driving system, steering system and braking system before designing. In the autonomous intelligent pure electric bus that I designed, whose transmission system USES a two - gear reducer, and selects the appropriate maximum gear ratio, minimum gear ratio, and main reduction ratio as required. Then check the transmission ratio by maximum speed and maximum climb. The bus environment perception system selects a three-dimensional laser radar to be placed on the roof of the vehicle. Two two-dimensional millimeter-wave radars are arranged at the front and rear of the vehicle, three cameras two of them at the front, one at the rear, and forty ultrasonic waves, four cars at the front of the car, four cars at the rear, one at every half meter. Finally, on the basis of these calculations, design the overall layout of the car.

Keywords: Autonomous intelligent pure electric bus; overall design; motor; battery; Chassis arrangement

List

Chapter one Introduction 1

1.1 Significance of topic 1

1.2 History of Autonomous intelligent pure electric bus 1

1.3 Main problems faced by Autonomous intelligent pure electric buses 4

Chapter Two Structure of bus 7

2.1 Axis number 7

2.2 Driven form 7

2.3 The layout of bus 7

Chapter Three Choice of the main parameters of the bus 9

3.1 Size parameters 9

3.1.1 Outside dimensions 9

3.1.2 Wheelbase 9

3.1.3 Front track and rear track 9

3.1.4 Front Suspensions and Rear Suspensions 10

3.2 Quality parameters 11

3.2.1Vehicle equipment quality 11

3.2.2 Car carrying capacity, loading quality ，total quality of the car 11

3. 2.3Axial load distribution 12

3.3 Determination of vehicle performance parameters 12

3.3.1 Maximum speed 12

3.3.2 Gradeability 13

3.4 Passive geometric parameters 13

3.5Handling stability parameters 13

3.6 Ride parameters 14

3.7Body form 14

3.8 Tire selection 14

Chapter Four Selection and Check of Autonomous intelligent pure electric bus Power System 15

4.1 Motor 15

4.2 Battery selection 17

4.3 Transmission Selection 18

4.4 Power Performance 19

Chapter Five Car chassis assembly selection and layout 20

5.1 Steering system 20

5.2 Braking System 20

Chapter Six Automatic driving principle 23

Chapter Seven Verification 26

7.1 Verification of maximum climbing grade 26

7.2 Verification of the maximum speed 26

7.3 The turn of the steering wheel 27

Chapter Eight Conclusion 29

Reference 30

Acknowledgements 31

Appendix 32

Chapter one Introduction

• 1. Significance of topic

As energy issues and environmental issues become increasingly prominent, the mode of power used by the existing vehicles can no longer meet the needs of future social development. For this reason, the development of electric vehicles has received extensive attention, and various types of electric vehicles are also under the research and development. Pure electric vehicle (EV) is a kind of vehicle which uses a single battery as the power source of energy storage, the vehicle is driven by electric motor, which meets the requirements of road traffic and safety regulations. PEV use batteries as a power source for energy storage, which provides electrical energy to the motor to drive the car. At present, the battery types of electric vehicles mainly include lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries. Autonomous intelligent technology plays an important role in reducing the driver's burden of driving and improving the safety of the vehicle. It is also an important part of the intelligent traffic system. In addition, Electric vehicles also have the advantages of energy saving and environmental protection and it becomes one of the development directions of vehicles in the future. They have increasingly become the hotspots of research in various countries. However, electric vehicles are different from traditional automobiles in terms of dynamical system, transmission system, and steering systems. Thus, the autonomous intelligent technology of the car is of great significance.

1.2 History of Autonomous intelligent pure electric bus

The development of new energy vehicles has gradually become a trend for social development with the increasing demand for “energy saving and low carbon”. Autonomous intelligent pure electric buses are an important part of the city in the future. Therefore, it is necessary to discuss the development of science and technology for driverless electric buses now.

Pure electric cars are the cars what are powered entirely by rechargeable batteries. It uses a rechargeable battery as a power source for energy storage. It uses a battery to provide electrical energy to the motor and drives the motor to drive the car. Autonomous intelligent technology plays an important role in reducing the driver's burden of driving and improving the safety of the vehicle. It is also an important part of the intelligent traffic system.

China has a good foundation for promoting the industrialization of pure electric vehicles. At present, in China, the number of light electric vehicles such as electric bicycles and electric motorcycles has exceeded 50 million, and the production and sales volume of light electric vehicles has exceeded 90 percent of the world's total. The development of light-duty electric vehicles has exerted a subtle influence on consumers while also stimulating the development of domestic power batteries and motors. In recent years, China's pure electric passenger cars have developed rapidly and their Ramp;D investment has continued to increase. China's research and development of pure electric buses mainly include buses and tourist buses. Among them, purely electric buses account for 85% of the total; luxury coaches account for 12%, and other uses have a small market share of 3%. At present, many automobile companies in China have also increased their input in the driverless area and have basically concentrated on passenger car companies. In April 2016, Chang An Automobile Co., Ltd. completed a 2000km unmanned solid road test from Chongqing to Beijing and achieved the third level of automatic driving. Among the numerous domestic bus companies, only a few passenger car companies have the development and application of driverless driving.

Yutong Bus Corporation, as a leading company in the domestic passenger car industry, jointly developed the world’s first driverless bus with the academician Li Deyi of the General Staff Department 61 and conducted an autonomous driving test on the intercity road between Zheng Zhou and Kai Feng in August 2015. In a completely open road environment, through 26 signal light intersections, it independently completes a series of experimental subjects such as follow-up driving, autonomous lane changing, adjoining road passing, automatic identification of traffic lights at crossings, fixed-point docking, etc., driving speed 32.6 km, and top speed 68 Km, reach the designated destination smoothly without any human intervention. The smart driving system of the whole vehicle mainly includes three main parts: an intelligent main controller, an intelligent sensing system, and an intelligent control system.