平衡小车调试指南：解决抖动和PWM输出问题 🛠️

一直对平衡车感兴趣，又找来一个平衡车的资料。以下内容主要转帖而来，原文http://www.geek-workshop.com/for ... &highlight=L298
小车整体造型大概是这个样子的
平衡小车图1

小车可以站住，但是小车抖动比较厉害。
使用的mpu6050，使用的一介互补滤波，得出角度 angle_x 。虽然原文作者调节了参数，但据说效果还不是很理想。
平衡小车图3

然后通过 if 语句进行判断 if(angle_x>0) 控制L298n
接下来就是把 angle_x 进行PID 控制。 Input = angle_x;
myPID.Compute();
Serial.print(Output=); 通过PID计算得出 Output 疑惑的是 Output竟然是0
平衡小车图4

Output=0       这是什么原因呢？？？？

然后把Output当做两个车轮的PWM脉冲，
  analogWrite(motor1PWMPin, Output);
  analogWrite(motor2PWMPin, Output);
Output=0 ，我测量motor1PWMPin motor2PWMPin两个管脚的电压还都是1.75，不管小车角度怎样，电压都不会改变。  ？？？？

设定小车的静态平衡角度为  Setpoint = 10.0;
初始 Input = 0.0;
  myPID.SetSampleTime(100); //采样时间
  myPID.SetMode(AUTOMATIC);

PID的调节 PID myPID(&Input, &Output, &Setpoint, 1, 0, -10, DIRECT);

调了几天，没什么效果，真是郁闷。。。
又查了一些资料，可能是电机太水，但是也有看到别人用香蕉电机的，效果也还不错。

斗就斗把，后来加了码盘，用了槽型对射管，对两个轮子进行测速，蓝牙控制准备让小车行走，就使用Arduino uon 的两个外部中断计脉冲的个数，
标志==40的时候车轮转动一圈，然后当接收到前进的命令的时候，让两个轮子全部正转2圈，但是经过测试小车一直在保持平衡，所以没时间正转2圈（这样理解可以吧）。所以这个控制程序不会写了。。。欢迎大神可提供帮助哦，到时候我也可以去帮帮原作者，装一下大神，哈哈

代码

#include<Wire.h>
#include "gyro_accel.h"
#include "PID_v1.h"

// Defining constants
#define dt 1            // time difference in milli seconds
#define rad2degree 57.3  // radian to degree conversion
#define Filter_gain 0.95  // e.g. angle = angle_gyro*Filter_gain + angle_accel*(1-Filter_gain)

// Global Variables
unsigned long t = 0;      // Time Variables
float angle_x_gyro=0, angle_y_gyro=0, angle_z_gyro=0, angle_x_accel=0, angle_y_accel=0, angle_z_accel=0, angle_x=0, angle_y=0, angle_z=0;
char val ;
int maichong,lefta,leftaa,leftone,righta,rightaa,rightone;
// DC motor driver with L298N
const int motor1PWMPin = 10; // PWM Pin of Motor 1
const int motor1Polarity1 = 9; // Polarity 1 Pin of Motor 1
const int motor1Polarity2 = 8;  // Polarity 2 Pin of Motor 1
const int motor2PWMPin = 5;  // PWM Pin of Motor 2
const int motor2Polarity1 = 6; // Polarity 1 Pin of Motor 2
const int motor2Polarity2 = 7;  // Polarity 2 Pin of Motor 2
const int left=0; //码盘
const int right=1;//码盘
int ValM1 = 255;  // Initial Value for PWM Motor 1
int ValM2 = 255;  // Initial Value for PWM Motor 2

double Setpoint, Input, Output;

PID myPID(&Input, &Output, &Setpoint, 1, 0, -10, DIRECT);
//PID myPID(&Input, &Output, &Setpoint, 25, 4, -5.5, DIRECT); 
void setup()
{
  // MPU-6050
  Serial.begin(115200);
  Wire.begin();
  MPU6050_ResetWake();
  MPU6050_SetGains(0,1);  // Setting the lows scale
  MPU6050_SetDLPF(0);    // Setting the DLPF to inf Bandwidth for calibration
  MPU6050_OffsetCal();  // very important
  MPU6050_SetDLPF(6);  // Setting the DLPF to lowest Bandwidth
   
  t = millis();
   
  // DC motor
  pinMode(motor1PWMPin, OUTPUT);
  pinMode(motor1Polarity1, OUTPUT);
  pinMode(motor1Polarity2, OUTPUT);
   
  pinMode(motor2PWMPin, OUTPUT);
  pinMode(motor2Polarity1, OUTPUT);
  pinMode(motor2Polarity2, OUTPUT);
  //0 1 zhongduan
attachInterrupt(left, jishu1, CHANGE);
attachInterrupt(right, jishu, CHANGE);
  
   
  // set enablePin of motor 1 high so that motor 1 can turn on
  digitalWrite(motor1PWMPin, HIGH);
  digitalWrite(motor1Polarity1, HIGH);
  digitalWrite(motor1Polarity2, LOW);

  // set enablePin of motor 2 high so that motor 2 can turn on  
  digitalWrite(motor2PWMPin, HIGH);
  digitalWrite(motor2Polarity1, HIGH);
  digitalWrite(motor2Polarity2, LOW);
   
  Input = 0.0;
  Setpoint = 10.0;
  
  myPID.SetSampleTime(100）; 
  myPID.SetMode(AUTOMATIC);
  
}
void jishu()
{  
    lefta++;
    if(lefta==45)
    {  
      lefta=0;  //mai chong biao zhi qing ling
      leftone++;//一圈
    }  
}
void jishu1()
{  
    righta++;
    if(righta==45)
    {  
      righta=0;  //mai chong biao zhi qing ling
      rightone++;//一圈
    }  
}
void rightz()//右轮正转
{
  digitalWrite(motor1PWMPin, HIGH);digitalWrite(motor1Polarity1, HIGH);digitalWrite(motor1Polarity2, LOW);
}
void rightf()//右轮反转
{
  digitalWrite(motor1PWMPin, HIGH);digitalWrite(motor1Polarity1, LOW);digitalWrite(motor1Polarity2, HIGH);
}
void leftz()
{
  digitalWrite(motor2PWMPin, HIGH);digitalWrite(motor2Polarity1, HIGH);digitalWrite(motor2Polarity2, LOW);
}
void leftf()
{
  digitalWrite(motor2PWMPin, HIGH);digitalWrite(motor2Polarity1, LOW);digitalWrite(motor2Polarity2, HIGH);
}
void st()//电机停
{
  digitalWrite(motor1PWMPin, HIGH);digitalWrite(motor1Polarity1, LOW);digitalWrite(motor1Polarity2, LOW);
  digitalWrite(motor2PWMPin, HIGH);digitalWrite(motor2Polarity1, LOW);digitalWrite(motor2Polarity2, LOW);
}
void blue()//蓝牙
{
  if (Serial.available() > 0) {
      val = Serial.read();
     /* if(val == 'A') { 
        Serial.println(angle_x); //jiaodu
      }*/
      if(val == 'z') {
       rightz();
      }
      if(val == 'x') {
      rightf();
      }
      if(val == 'c') {
       leftz();
      }
      if(val == 'v') {
       leftf();
      }
      if(val == 'b') {
       st();
      }
}}
void loop()
{
  t = millis();
  
  MPU6050_ReadData();
   
  angle_x_gyro = (gyro_x_scalled*((float)dt/1000)+angle_x);
  angle_y_gyro = (gyro_y_scalled*((float)dt/1000)+angle_y);
  angle_z_gyro = (gyro_z_scalled*((float)dt/1000)+angle_z);

  angle_z_accel = atan(accel_z_scalled/(sqrt(accel_y_scalled*accel_y_scalled+accel_x_scalled*accel_x_scalled)))*(float)rad2degree;
  angle_y_accel = -atan(accel_x_scalled/(sqrt(accel_y_scalled*accel_y_scalled+accel_z_scalled*accel_z_scalled)))*(float)rad2degree;
  angle_x_accel = atan(accel_y_scalled/(sqrt(accel_x_scalled*accel_x_scalled+accel_z_scalled*accel_z_scalled)))*(float)rad2degree;

  angle_x = Filter_gain*angle_x_gyro+(1-Filter_gain)*angle_x_accel;
  angle_y = Filter_gain*angle_y_gyro+(1-Filter_gain)*angle_y_accel;
  angle_z = Filter_gain*angle_z_gyro+(1-Filter_gain)*angle_z_accel;
   
  digitalWrite(motor1PWMPin, HIGH);
  digitalWrite(motor2PWMPin, HIGH);

Serial.print("\n");Serial.print("    ");Serial.print("angle_x=");  Serial.print(angle_x);Serial.print("  ");Serial.print("angle_y=");Serial.print(angle_y);Serial.print("  ");Serial.print("angle_z=");Serial.print(angle_z);
Serial.print("____");           //串口输出
   
  // change direction is very important   平衡
  if(angle_x>0)
  {
    myPID.SetControllerDirection(REVERSE);
     
    // set enablePin of motor 1 high so that motor 1 can turn on
    digitalWrite(motor1Polarity1, HIGH);
    digitalWrite(motor1Polarity2, LOW);

    // set enablePin of motor 2 high so that motor 2 can turn on  
    digitalWrite(motor2Polarity1, HIGH);
    digitalWrite(motor2Polarity2, LOW);
  }
  else
  {
    myPID.SetControllerDirection(DIRECT);
    // set enablePin of motor 1 high so that motor 1 can turn on
    digitalWrite(motor1Polarity1, LOW);
    digitalWrite(motor1Polarity2, HIGH);

    // set enablePin of motor 2 high so that motor 2 can turn on  
    digitalWrite(motor2Polarity1, LOW);
    digitalWrite(motor2Polarity2, HIGH);
  }
   
  Input = angle_x;
  Serial.print("Input=");Serial.print(Input);Serial.print("____");
   
  myPID.Compute();
  Serial.print("Output=");Serial.print(Output);Serial.print("____");                        Output 怎么会是0？？？？
   
  analogWrite(motor1PWMPin, Output);
  analogWrite(motor2PWMPin, Output);
  
  Serial.print("Setpoint=");Serial.print(Setpoint); Serial.print("\t");
  Serial.print("left=");Serial.print(lefta);Serial.print("  ");Serial.print(leftone); Serial.print("\t");
  Serial.print("right=");Serial.print(righta);Serial.print("  ");Serial.print(rightone); Serial.print("\t");   //串口输出
   blue();//蓝牙
   
   if(rightone==1) //转动1圈标志
       {
         rightone=0;    
         st();   // 停止转动
       }
       
   
  while((millis()-t) < dt) 
  {
    // Do nothing
  }
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