摘 要

随着可用能源的日渐紧张以及环境污染的不断加重，新能源汽车技术也不断发展壮大，无人驾驶电动工程车是一种针对于新加坡地下管网系统特点设计的维护类型车辆，此类车辆采用铅酸蓄电池为动力源，具有体积小、可双向行驶、可拖挂、可实现有人驾驶等特点。

制动系统作为汽车控制系统的核心部分，它和无人驾驶技术的安全运行有着密切的联系，因此，设计出一款具有高稳定性、高可靠性的制动系统对无人驾驶技术的发展有着极其重要的指导意义。

本文主要研究了无人驾驶电动工程维护车当中制动系统的设计，首先在设计方案的选取上，行车制动采用液力制动结合电机制动的方法，不仅极大的保证了制动的高有效性和准确性，而且电机制动可实现制动能量的再生回收，在很大程度上节约了能源，提高了工程车的能源利用率；驻车制动采用集成式电子驻车式制动器，这种形式的设计改善了传统手拉杆式的设计，极大的节约了布置空间；同时制动踏板采用可收缩式设计，不仅节约空间，而且可实现有人驾驶和无人驾驶的切换。并且以上说明的所有设计都与各类适当的传感器相匹配设计，有效的实现信号的准确传递以至于实现高稳定性和高准确性的无人驾驶。最后根据已知参数与要求和求解出的参数对此制动系统进行了系统的建模与性能分析，并绘制了电动工程车制动系统的零件和装配图。

关键词：无人驾驶；伺服制动；盘式制动器；

Abstract .

With a continuous decreasing trend of available energy and the serious situation of environment pollution, vehicles of new energy keeps beaning developed and expanded. Unmanned electric vehicle is a kind of maintenance vehicle which is designed according to the characteristics of the underground pipe network system in Singapore. It takes lead-acid battery as the power source, and it is equipped with following characteristics: small size, two-way driving, can be dragged and so on.

The braking system, as the core part of the vehicle control system, is closely related with the safe operation of unmanned technology. Therefore, developing a brake system with high stability and high reliability for unmanned technology plays a very important role in the development of unmanned technology.

In this paper, we mainly studied the design of the brake system in the unmanned electric engineering maintenance vehicle. Firstly, as for the selection of the design program, we attach hydraulic braking with motor braking to ensure driving braking, which not only greatly guarantees the braking with high efficiency and accuracy, and the motor brake can achieve the regeneration of brake energy. In this way we can save energy and improve the energy efficiency to a large extent; and we use electronic parking brake for parking brake, which improves the traditional hand bar and saves a lot layout space. At the same time, we adopt the retractable brake pedal, which can not only saves space, but also can achieve good person and unmanned driving switching. And all the design above are matched with some appropriate sensors, the effective signal transmission ensures of high stability and high accuracy of unmanned driving. Finally, according to the known parameters and requirements and calculated parameters of the brake system to make modeling and performance analysis and get the electric vehicle brake system parts and assembly drawings.

Key Words：unmanned driving；servo brake；disk brakes；

Contents

1. Introduction 1

1.1 Purpose and Significance of Braking System Design for Unmanned Electric Vehicle 1

1.1.1 Domestic and foreign Research Status of Unmanned Electric Vehicles 1

1.1.2 Research Status of Design Scheme for Electric Vehicle Braking System 2

1.2 Main contents of this paper 3

2. Analysis and Selection of Braking System Scheme for Unmanned Electric Vehicle 4

2.1 Control Flow of Unmanned Electric Engineering Vehicle Braking System 4

2.2 Analysis and Selection of Brake for Unmanned Electric Vehicle 5

2.3 Analysis and Selection of Driving mechanism for Unmanned Electric Vehicle Braking System 7

2.4 Analysis and Selection of Executive body for Unmanned Electric Vehicle Braking System 9

2.4.1 Analysis and Selection of Hydraulic Shunt System 9

2.4.2 Analysis and Selection of Hydraulic Shunt System 10

2.4.3 Design and Analysis of Brake Pedal in Man Driving Mode 10

2.5 Analysis and Selection of Parking System for Unmanned Electric Vehicle 11

2.6 Motor Regenerative Braking of Unmanned Braking System 12

3. Design and Calculation of Braking System for Unmanned Electric Vehicle 14

3.1 Calculation and Analysis of Main Parameters of Braking System for Unmanned Electric Vehicle 14

3.1.1 Braking force and braking force distribution coefficient 14

3.1.2 Maximum braking torque Brake 16

3.1.3 Brake effectiveness factor 17

3.2 Design and Calculation of Brake for Unmanned Electric Vehicle 17

3.2.1 Calculation of Braking Torque for Brake 17

3.2.2 Calculation of compression force of Brake 18

3.2.3 Determination of the main parameters of disk brakes 19

3.3 Design and Calculation of Hydraulic Braking Mechanism for Unmanned Electric Vehicle 22

3.3.1 Determination of the diameter of the brake wheel 22

3.3.2 Determination of the diameter of the cylinder 22

3.3.3 Determination of brake pedal force and brake pedal work stroke 23

3.3.4 Design and Calculation of Parking Braking for Unmanned Electric Vehicle 24

4. Performance Analysis and Parts Checking of Braking System for Unmanned Electric Vehicle 26

4.1 Evaluation Index of Braking Performance for Unmanned Electric Vehicle 26

4.2 Calculation of Brake Deceleration and Braking Distance of Unmanned Electric vehicle 26

4.3 Analysis and Calculation of Frictional Characteristics for Brake pads 27

4.3.1 Energy dissipation rate of friction pad 27

4.3.2 Frictional force of brake pads 28

4.4 Check and Analysis of Brake for Unmanned Electric Vehicle 28

4.4.1 Temperature rise of heat capacity and check feedbacks 28

4.4.2 ANSYS strength check of Brake disk 29

5. Design summary 31

References 32

Acknowledgements 34

Appendix 35

Introduction

Purpose and Significance of Braking System Design for Unmanned Electric Vehicle

Unmanned electric vehicle is a kind of intelligent vehicle that it can feel surroundings by vehicle sensors. It acquires information about driving roads, obstructions around the vehicle and vehicle position according to feeling data. And furthermore it can make good control of vehicle steering and velocity. In this way the vehicle can not only travel on the road safely and reliably, but also greatly reducing the human’s impact on the vehicle safety performance. In addition, as a kind of underground pipe network maintenance vehicle, the frequency of braking is very high, the maintenance staff can concentrate on the maintenance of the survey and assessment after using unmanned technology, they can make quick and accurate reflection .In this way, it makes great assurance of the efficiency for underground pipeline maintenance work and also reduces the additional workload for maintenance personnel.

At the same time, unmanned electric vehicles only consume electricity, it does not need to consume the fuel that may cause serious environment pollution. And the source of electricity is also quite extensive: such as hydroelectric power, nuclear power generation, solar power, wind power etc. With an increasing development of new energy vehicle technology, more and more unmanned electric vehicles are applied to the actual project and play good effect.