给ch32v307写一份pid串级控制代码，使得直立小车可以平衡

下面是一个基于PID串级控制的直立小车平衡代码的示例：

// PID Constants
float velocityKp = 0.1;  // Velocity Loop Proportional Gain
float velocityKi = 0.01; // Velocity Loop Integral Gain
float velocityKd = 0.05; // Velocity Loop Derivative Gain

float angleKp = 10;      // Angle Loop Proportional Gain
float angleKi = 0.1;     // Angle Loop Integral Gain
float angleKd = 0.5;     // Angle Loop Derivative Gain

// Variables
float velocitySetpoint = 0;
float angleSetpoint = 0;

float velocityInput = 0;
float angleInput = 0;

float velocityOutput = 0;
float angleOutput = 0;

float velocityErrorSum = 0;
float angleErrorSum = 0;

float velocityLastError = 0;
float angleLastError = 0;

unsigned long loopTime = 0;

void setup() {
  // Initialize motors, sensors, and other peripherals
}

void loop() {
  unsigned long currentTime = millis();
  float dt = (currentTime - loopTime) / 1000.0; // Calculate time difference in seconds
  loopTime = currentTime;
  
  // Read encoder data and calculate velocity input
  float encoderData = getEncoderData(); // Replace with actual function to read encoder data
  velocityInput = encoderData / dt; // Calculate velocity by dividing change in encoder data by time
  
  // Velocity Loop
  float velocityError = velocitySetpoint - velocityInput;
  velocityErrorSum += (velocityError * dt);
  float velocityErrorRate = (velocityError - velocityLastError) / dt;
  
  velocityOutput = velocityKp * velocityError + velocityKi * velocityErrorSum + velocityKd * velocityErrorRate;
  velocityLastError = velocityError;
  
  // Read gyroscope data and calculate angle input
  float gyroData = getGyroData(); // Replace with actual function to read gyroscope data
  angleInput = integrateGyroData(gyroData, dt); // Integrate gyroscope data to get angle
  
  // Angle Loop
  float angleError = angleSetpoint - angleInput;
  angleErrorSum += (angleError * dt);
  float angleErrorRate = (angleError - angleLastError) / dt;
  
  angleOutput = angleKp * angleError + angleKi * angleErrorSum + angleKd * angleErrorRate;
  angleLastError = angleError;
  
  // Calculate motor PWM values based on velocity and angle outputs
  float leftMotorPWM = velocityOutput + angleOutput;
  float rightMotorPWM = velocityOutput - angleOutput;
  
  // Apply motor PWM values to control the motors
  
  // Delay for a short period of time
  delay(10); // Adjust the delay value as needed based on the control loop frequency
}

// Function to integrate gyroscope data and get angle
float integrateGyroData(float gyroData, float dt) {
  static float integratedAngle = 0;
  integratedAngle += gyroData * dt;
  return integratedAngle;
}

// Function to get encoder data
float getEncoderData() {
  // Replace with actual code to read encoder data
  return 0.0;
}

// Function to get gyroscope data
float getGyroData() {
  // Replace with actual code to read gyroscope data
  return 0.0;
}

请注意，上述示例代码中的PID参数（如`velocityKp`、`velocityKi`、`velocityKd`、`angleKp`、`angleKi`、`angleKd`）需要根据实际情况进行调整和优化。此外，还需要替换示例代码中的函数`getEncoderData()`和`getGyroData()`来读取实际的编码器和陀螺仪数据。最后，确保按照实际控制循环的频率进行延迟，以使控制系统按照期望的频率运行。