外文文獻(xiàn)與翻譯--基于嵌入式平臺(tái)的智能小車控制器的設(shè)計(jì)-wenkub
2023-05-19 12:24:48 本頁(yè)面
【正文】 ses of the car. PWM generating module inside it can be change duty cycle of outputted square wave by programming, and thus change the voltage loaded on the DC motor, which is amplified to control the revolution speed of the motor. The ports PA0, PA1, PA2 and PA3 of the PWM module respectively control the DC motor and the steering motor to perform functions such as go forward, retreat and turn etc. Design of power module The car is powered by four AA dry batteries. The voltage is outputted through lowNoise LDO regulator to supply power for ARM7 chips and peripheral circuits. The working current of is as high as 500mA. When input voltage is above , the module of can output stable voltage of and achieve low power consumption. Temperature detection Module Monoline digital temperature sensor DS18B20 is used to detect temperature in the car. The measure range is from 55℃ to +125℃ , with increment of ℃ . It is low in power consumption and small in size, occupying only one I/O port. Auto tracking module Principles for tracking of intelligent car Tracking means that the car goes along the twocentimeterwide black guide line on the white floor. Infrared acquisition and camera shooting acquisition are monly used for it. Infrared acquisition: Taking advantage of the feature that infrared light can change its reflective quality according to object surface of various colors. During running the car continuously sends infrared light to the ground, which will, either be reflected back by the white floor and received by the receiving tube in the car, or be absorbed by the black guide line and thus missed by the receiving tube. By this means the black guide line is positioned to identify the path for the car. Camera shooting acquisition: In certain resolution sample the image by interlaced scanning. When scanning a point, image sensor transfers the gray threshold into corresponding voltage which will be outputted via video signal port. As the car achieves auto tracking by recognizing the black guide line on the track, the image processing is a process of extracting the destination guide line. The task of image processing program is to identify the dots in the blackandwhite image and filter noise, record dot positions relative to the image, and finally, by algorithm of control strategy, realize tracking and turning of the car along the guide line. Installation of tracking infrared probe Choosing proper detection method and sensor is the important factor to achi
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