小车超声波避障pid算法c语言实现

下面是一个简单的超声波避障PID算法的C语言实现，仅供参考：

#include <stdio.h>
#include <stdlib.h>
#include <wiringPi.h>

#define TRIG_PIN 4
#define ECHO_PIN 5
#define MOTOR_PIN 1
#define PWM_RANGE 100

const int KP = 20;
const int KD = 5;
const int KI = 0;
const int TARGET_DISTANCE = 30; // 目标距离为30cm

int prev_error = 0;
int integral = 0;

int read_distance() {
    digitalWrite(TRIG_PIN, LOW);
    delayMicroseconds(2);
    digitalWrite(TRIG_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG_PIN, LOW);
    long duration = pulseIn(ECHO_PIN, HIGH);
    return duration / 58; // 将微秒转化为厘米
}

void adjust_motor(int error) {
    int pwm_value = KP * error + KD * (error - prev_error) + KI * integral;
    prev_error = error;
    integral += error;

    if (pwm_value > PWM_RANGE) pwm_value = PWM_RANGE;
    if (pwm_value < -PWM_RANGE) pwm_value = -PWM_RANGE;

    if (pwm_value > 0) {
        digitalWrite(MOTOR_PIN, HIGH);
        softPwmWrite(MOTOR_PIN, pwm_value);
    } else {
        digitalWrite(MOTOR_PIN, LOW);
        softPwmWrite(MOTOR_PIN, -pwm_value);
    }
}

int main() {
    wiringPiSetup();
    pinMode(TRIG_PIN, OUTPUT);
    pinMode(ECHO_PIN, INPUT);
    pinMode(MOTOR_PIN, OUTPUT);
    softPwmCreate(MOTOR_PIN, 0, PWM_RANGE);

    while (1) {
        int distance = read_distance();
        int error = TARGET_DISTANCE - distance;
        adjust_motor(error);
    }

    return 0;
}

该代码使用了树莓派的WiringPi库来控制GPIO口和软件PWM输出，需要在编译时链接该库。该算法的实现比较简单，使用PID算法来调整电机的转速，使小车保持在目标距离附近。其中KP、KD和KI是PID算法中的三个参数，需要根据实际情况进行调整。