stm32循迹小车pid算法

PID算法是一种常用的控制算法，对于循迹小车的控制也可以使用PID算法进行控制。下面是一个简单的基于STM32的循迹小车PID算法实现的示例代码：

#include "stm32f10x.h"

#define KP 10.0f   // 比例系数
#define KI 0.5f    // 积分系数
#define KD 0.1f    // 微分系数

#define LEFT_SPEED  TIM4->CCR1
#define RIGHT_SPEED TIM4->CCR2

void TIM4_PWM_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    TIM_TimeBaseStructure.TIM_Period = 7200 - 1;
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

    TIM_OC1Init(TIM4, &TIM_OCInitStructure);
    TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_OC2Init(TIM4, &TIM_OCInitStructure);
    TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_Cmd(TIM4, ENABLE);
}

float calculate_pid(float error, float last_error, float integral)
{
    float p, i, d;

    p = KP * error;
    i = KI * integral;
    d = KD * (error - last_error);

    return p + i + d;
}

int main(void)
{
    float error, last_error = 0, integral = 0, pid_value;
    int left_speed, right_speed;

    TIM4_PWM_Init();

    while (1)
    {
        // 获取传感器读数
        error = get_sensor_error();

        // 计算积分项
        integral += error;

        // 计算PID值
        pid_value = calculate_pid(error, last_error, integral);

        // 计算左右轮速度
        left_speed = (int)(100 - pid_value);
        right_speed = (int)(100 + pid_value);

        // 设置左右轮速度
        LEFT_SPEED = (left_speed > 100) ? 100 : left_speed;
        RIGHT_SPEED = (right_speed > 100) ? 100 : right_speed;

        // 更新误差值
        last_error = error;
    }
}

该示例代码中使用了TIM4定时器作为PWM输出控制左右轮速度，使用calculate_pid函数计算PID值，get_sensor_error函数获取传感器读数，具体实现需要根据实际情况进行修改。