Intelligent Car With Automatic Route Recognition

Project Cycle: May.2014–Oct.2015

Table of Contents

1. Abstract

This research taked Freescale (NXP) Cup Intelligent Car Race as the starting point, lasted for nearly two years, finally achieved excellent results in the race.

The intelligent car system (figure 1) is composed of camera, steering gear, motor, speed encoder, MCU and car model, with functions such as track information acquisition, steering control and speed control. The system operates by first using the camera to complete the track information collection, then processing the image to plan the driving path of the car, and finally using the steering gear to control the steering and the motor for acceleration and deceleration control.

The intelligent car system
The intelligent car system

In order to win the race, it is necessary to distinguish various complex track types, such as straights, curves, S-curves, cross-curves and right-angle curves, so as to achieve reasonable control of steering and speed and enable the car to pass different track types quickly and stably.

2. Hardware design

2.1. System constitute

The intelligent car mainly includes the main control board, drive board, camera, MCU, motor and steering gear, as shown in Figure 2.

The car constitute
The car constitute

2.2. PCB design

The main control board circuit includes: power supply, motor control interface, communication interface, switch, MCU slot, etc, as shown in Figure 3 and 4.

The main control board schematic diagram
The main control board schematic diagram
The main control board PCB
The main control board PCB

The motor driving circuit is designed according to the official Manual of BTS7960 chip, as shown in Figure 5 and 6.

The motor driver board schematic diagram
The motor driver board schematic diagram
The motor driver board PCB
The motor driver board PCB

3. Software Design

3.1. Image processing

The binary image is collected by digital camera, and then the edge information of the track is extracted, so as to calculate the center line position of the track. In order to speed up the S-curve, the weighted average algorithm is used to optimize the path, and the weight of each line in the whole image is adjusted to achieve better path planning.(Figure 7)

Image processing
Image processing

3.2. Control algorithm

Incremental PID control algorithm is used to control the steering gear and motor speed. Advantages of incremental algorithm: no integral calculation is needed in the calculation process, the calculation complexity is low, and the output result is the control increment each time, so the influence range is small when the machine fails.

PID Control
PID Control

3.3. Development tool

The development tool
The development tool

4. Achievements

4.1. Car race Live video

4.2. Award

The National Second prize of Freescale(NXP) Cup Intelligent Car Race
The National Second prize of Freescale(NXP) Cup Intelligent Car Race
Xu Wei
Xu Wei
Software Engineer

The charm of technology is the perfect combination of hardware and software.

Related