stm32麦克纳姆轮小车pid控制程序

下面是一个基于STM32的麦克纳姆轮小车PID控制程序的示例，供参考：

首先，需要定义一些常量和变量：

#define PI 3.14159265358979323846f
#define WHEEL_DIAMETER 0.05f // 轮子直径
#define WHEEL_DISTANCE 0.2f  // 轮子间距

float pid_kp = 1.0f; // PID控制器的比例系数
float pid_ki = 0.0f; // PID控制器的积分系数
float pid_kd = 0.0f; // PID控制器的微分系数

float target_velocity_x = 0.0f; // 目标x轴速度
float target_velocity_y = 0.0f; // 目标y轴速度
float target_angular_velocity = 0.0f; // 目标角速度

float current_velocity_x = 0.0f; // 当前x轴速度
float current_velocity_y = 0.0f; // 当前y轴速度
float current_angular_velocity = 0.0f; // 当前角速度

float velocity_error_x = 0.0f; // x轴速度误差
float velocity_error_y = 0.0f; // y轴速度误差
float angular_velocity_error = 0.0f; // 角速度误差

float velocity_error_integral_x = 0.0f; // x轴速度误差积分
float velocity_error_integral_y = 0.0f; // y轴速度误差积分
float angular_velocity_error_integral = 0.0f; // 角速度误差积分

float velocity_error_previous_x = 0.0f; // 用于微分的上一次速度误差
float velocity_error_previous_y = 0.0f; // 用于微分的上一次速度误差
float angular_velocity_error_previous = 0.0f; // 用于微分的上一次角速度误差

float pwm_motor1 = 0.0f; // 电机1的PWM输出
float pwm_motor2 = 0.0f; // 电机2的PWM输出
float pwm_motor3 = 0.0f; // 电机3的PWM输出
float pwm_motor4 = 0.0f; // 电机4的PWM输出

float wheel_speed1 = 0.0f; // 电机1输出的轮速
float wheel_speed2 = 0.0f; // 电机2输出的轮速
float wheel_speed3 = 0.0f; // 电机3输出的轮速
float wheel_speed4 = 0.0f; // 电机4输出的轮速

uint32_t last_time = 0; // 上一次计算PID的时间

然后，需要编写一个PID计算函数，用来根据误差计算出PWM输出：

void pid_compute(float *pwm1, float *pwm2, float *pwm3, float *pwm4, uint32_t current_time)
{
    float delta_time = (current_time - last_time) / 1000.0f;

    velocity_error_x = target_velocity_x - current_velocity_x;
    velocity_error_y = target_velocity_y - current_velocity_y;
    angular_velocity_error = target_angular_velocity - current_angular_velocity;

    velocity_error_integral_x += velocity_error_x * delta_time;
    velocity_error_integral_y += velocity_error_y * delta_time;
    angular_velocity_error_integral += angular_velocity_error * delta_time;

    float velocity_error_derivative_x = (velocity_error_x - velocity_error_previous_x) / delta_time;
    float velocity_error_derivative_y = (velocity_error_y - velocity_error_previous_y) / delta_time;
    float angular_velocity_error_derivative = (angular_velocity_error - angular_velocity_error_previous) / delta_time;

    *pwm1 = pid_kp * velocity_error_x + pid_ki * velocity_error_integral_x + pid_kd * velocity_error_derivative_x;
    *pwm2 = pid_kp * velocity_error_y + pid_ki * velocity_error_integral_y + pid_kd * velocity_error_derivative_y;
    *pwm3 = pid_kp * angular_velocity_error + pid_ki * angular_velocity_error_integral + pid_kd * angular_velocity_error_derivative;
    *pwm4 = 0.0f; // 第四个电机不使用

    velocity_error_previous_x = velocity_error_x;
    velocity_error_previous_y = velocity_error_y;
    angular_velocity_error_previous = angular_velocity_error;

    last_time = current_time;
}

最后，在主循环中，读取传感器数据，计算当前速度和角速度，然后调用PID计算函数计算PWM输出：

while (1)
{
    // 读取传感器数据
    float imu_heading = read_imu_heading();
    float encoder1 = read_encoder1();
    float encoder2 = read_encoder2();
    float encoder3 = read_encoder3();
    float encoder4 = read_encoder4();

    // 计算当前速度和角速度
    float wheel_speeds[4] = { 0 };
    wheel_speeds[0] = (encoder1 / 360.0f) * WHEEL_DIAMETER * PI;
    wheel_speeds[1] = (encoder2 / 360.0f) * WHEEL_DIAMETER * PI;
    wheel_speeds[2] = (encoder3 / 360.0f) * WHEEL_DIAMETER * PI;
    wheel_speeds[3] = (encoder4 / 360.0f) * WHEEL_DIAMETER * PI;
    current_velocity_x = (-wheel_speeds[0] + wheel_speeds[1] + wheel_speeds[2] - wheel_speeds[3]) / 4.0f;
    current_velocity_y = (wheel_speeds[0] + wheel_speeds[1] - wheel_speeds[2] - wheel_speeds[3]) / 4.0f;
    current_angular_velocity = (wheel_speeds[0] + wheel_speeds[1] + wheel_speeds[2] + wheel_speeds[3]) / (4.0f * WHEEL_DISTANCE);

    // 调用PID计算函数计算PWM输出
    uint32_t current_time = get_current_time();
    pid_compute(&pwm_motor1, &pwm_motor2, &pwm_motor3, &pwm_motor4, current_time);

    // 输出PWM信号到电机
    set_motor_pwm(MOTOR1, pwm_motor1);
    set_motor_pwm(MOTOR2, pwm_motor2);
    set_motor_pwm(MOTOR3, pwm_motor3);
    set_motor_pwm(MOTOR4, pwm_motor4);
}

需要注意的是，这只是一个简单的示例，实际应用中需要根据具体情况进行调整和改进。