Diego 1# 4WD —3：上位機通訊

ROS Arduino Bridge本質上是上位機通過串口發送控制命令來實現對Arduino的控制，所以我們要實現4驅的控制，我們也必須的修改通訊部分
1.Arduino firmware修改
1.1 command.h
在此文件中增加4驅所需的命令及宏定義

#ifndef COMMANDS_H
#define COMMANDS_H

#define ANALOG_READ    'a'
#define GET_BAUDRATE   'b'
#define PIN_MODE       'c'
#define DIGITAL_READ   'd'
#define READ_ENCODERS  'e'
#define MOTOR_SPEEDS   'm'
#define PING           'p'
#define RESET_ENCODERS 'r'
#define SERVO_WRITE    's'
#define SERVO_READ     't'
#define UPDATE_PID     'u'
#define DIGITAL_WRITE  'w'
#define ANALOG_WRITE   'x'
#define LEFT            0
#define RIGHT           1
#define LEFT_H          2 //新增
#define RIGHT_H         3 //新增
#define READ_PIDOUT    'f'
#define READ_PIDIN     'i'
#define READ_MPU6050   'g'

#endif

1.2 RosArduinoBridge-diego.ino
此文件是主程序，由於此文件代碼比較多，故這裏只介紹新增部分代碼，完整的代碼請見github
在runCommand()函數中修改在4驅模式下讀取pidin 的代碼

    case READ_PIDIN:
      Serial.print(readPidIn(LEFT));
      Serial.print(" ");
#ifdef L298P      
      Serial.println(readPidIn(RIGHT));
#endif
#ifdef L298P_4WD 
      Serial.print(readPidIn(RIGHT));
      Serial.print(" ");
      Serial.print(readPidIn(LEFT_H));
      Serial.print(" ");
      Serial.println(readPidIn(RIGHT_H));
#endif      
      break;

在runCommand()函數中修改在4驅模式下讀取pidout 的代碼

    case READ_PIDOUT:
      Serial.print(readPidOut(LEFT));
      Serial.print(" ");
#ifdef L298P      
      Serial.println(readPidOut(RIGHT));
#endif
#ifdef L298P_4WD 
      Serial.print(readPidOut(RIGHT));
      Serial.print(" ");
      Serial.print(readPidOut(LEFT_H));
      Serial.print(" ");
      Serial.println(readPidOut(RIGHT_H));
#endif       
      break;

在runCommand()函數中修改在4驅模式下讀取編碼器數據的代碼

    case READ_ENCODERS:
      Serial.print(readEncoder(LEFT));
      Serial.print(" ");
#ifdef L298P 
      Serial.println(readEncoder(RIGHT));
#endif
#ifdef L298P_4WD
      Serial.print(readEncoder(RIGHT));
      Serial.print(" ");
      Serial.print(readEncoder(LEFT_H));
      Serial.print(" ");
      Serial.println(readEncoder(RIGHT_H));
#endif      
      break;

在runCommand()函數中修改在4驅模式下設置馬達速度的代碼

    case MOTOR_SPEEDS:
      /* Reset the auto stop timer */
      lastMotorCommand = millis();
      if (arg1 == 0 && arg2 == 0) {
#ifdef L298P        
        setMotorSpeeds(0, 0);
#endif

#ifdef L298P_4WD
        setMotorSpeeds(0, 0, 0, 0);
#endif        
        moving = 0;
      }
      else moving = 1;
      leftPID.TargetTicksPerFrame = arg1;
      rightPID.TargetTicksPerFrame = arg2;
#ifdef L298P_4WD      
      leftPID_h.TargetTicksPerFrame = arg1;
      rightPID_h.TargetTicksPerFrame = arg2;
#endif       
      Serial.println("OK");
      break;

在runCommand()函數中修改在4驅模式下更新PID參數的代碼

case UPDATE_PID:
      while ((str = strtok_r(p, ":", &p)) != '\0') {
        pid_args[i] = atoi(str);
        i++;
      }

      left_Kp = pid_args[0];
      left_Kd = pid_args[1];
      left_Ki = pid_args[2];
      left_Ko = pid_args[3];

      right_Kp = pid_args[4];
      right_Kd = pid_args[5];
      right_Ki = pid_args[6];
      right_Ko = pid_args[7];

#ifdef L298P_4WD

      left_h_Kp = pid_args[0];
      left_h_Kd = pid_args[1];
      left_h_Ki = pid_args[2];
      left_h_Ko = pid_args[3];

      right_h_Kp = pid_args[4];
      right_h_Kd = pid_args[5];
      right_h_Ki = pid_args[6];
      right_h_Ko = pid_args[7];
#endif
      
      Serial.println("OK");
      break;

在setup()函數中設置在4驅模式下新增的pin對應的寄存器的操作

void setup() {
  Serial.begin(BAUDRATE);
#ifdef USE_BASE
#ifdef ARDUINO_ENC_COUNTER
  //set as inputs
  DDRD &= ~(1 << LEFT_ENC_PIN_A);
  DDRD &= ~(1 << LEFT_ENC_PIN_B);
  DDRC &= ~(1 << RIGHT_ENC_PIN_A);
  DDRC &= ~(1 << RIGHT_ENC_PIN_B);

#ifdef L298P_4WD
  DDRD &= ~(1 << LEFT_H_ENC_PIN_A);
  DDRD &= ~(1 << LEFT_H_ENC_PIN_B);
  DDRC &= ~(1 << RIGHT_H_ENC_PIN_A);
  DDRC &= ~(1 << RIGHT_H_ENC_PIN_B);
#endif  

  //enable pull up resistors
  PORTD |= (1 << LEFT_ENC_PIN_A);
  PORTD |= (1 << LEFT_ENC_PIN_B);
  PORTC |= (1 << RIGHT_ENC_PIN_A);
  PORTC |= (1 << RIGHT_ENC_PIN_B);

#ifdef L298P_4WD
  PORTD &= ~(1 << LEFT_H_ENC_PIN_A);
  PORTD &= ~(1 << LEFT_H_ENC_PIN_B);
  PORTC &= ~(1 << RIGHT_H_ENC_PIN_A);
  PORTC &= ~(1 << RIGHT_H_ENC_PIN_B);
#endif    
  // tell pin change mask to listen to left encoder pins
  PCMSK2 |= (1 << LEFT_ENC_PIN_A) | (1 << LEFT_ENC_PIN_B);
  // tell pin change mask to listen to right encoder pins
  PCMSK1 |= (1 << RIGHT_ENC_PIN_A) | (1 << RIGHT_ENC_PIN_B);

#ifdef L298P_4WD
  // tell pin change mask to listen to left encoder pins
  PCMSK2 |= (1 << LEFT_ENC_PIN_A) | (1 << LEFT_ENC_PIN_B) | (1 << LEFT_H_ENC_PIN_A) | (1 << LEFT_H_ENC_PIN_B);
  // tell pin change mask to listen to right encoder pins
  PCMSK1 |= (1 << RIGHT_ENC_PIN_A) | (1 << RIGHT_ENC_PIN_B) | (1 << RIGHT_H_ENC_PIN_A) | (1 << RIGHT_H_ENC_PIN_B);
#endif
  // enable PCINT1 and PCINT2 interrupt in the general interrupt mask
  PCICR |= (1 << PCIE1) | (1 << PCIE2);
#endif
  initMotorController();
  resetPID();
#endif

  /* Attach servos if used */
#ifdef USE_SERVOS
  int i;
  for (i = 0; i < N_SERVOS; i++) {
    servosPos[i]=90;
  }
  servodriver.begin();
  servodriver.setPWMFreq(50);
#endif
}

在loop()函數中修改在4驅模式下自動停止的邏輯

  // Check to see if we have exceeded the auto-stop interval
  if ((millis() - lastMotorCommand) > AUTO_STOP_INTERVAL) {
    ;
#ifdef L298P    
    setMotorSpeeds(0, 0);
#endif
#ifdef L298P_4WD
    setMotorSpeeds(0, 0, 0, 0);
#endif
    moving = 0;
  }

#endif

2.上位機代碼修改
上位機的代碼修改主要是針對arduino_driver.py和base_controller.py的修改。

2.1 arduino_driver.py修改
修改def get_pidin(self):使其支持4個電機的pidin讀取

  def get_pidin(self):
        values = self.execute_array('i')
        print("pidin_raw_data: "+str(values))
        if len(values) not in [2,4]:
            print "pidin was not 2 or 4 for 4wd"
            raise SerialException
            return None
        else:                                                                  
            return values

修改def get_pidout(self):使其支持4個電機的pidout讀取

    def get_pidout(self):
        values = self.execute_array('f')
        print("pidout_raw_data: "+str(values))
        if len(values) not in [2,4]:
            print "pidout was not 2 or 4 for 4wd"
            raise SerialException
            return None
        else:                                                                  
            return values

修改def get_encoder_counts(self):使其支持4個電機的編碼器數據讀取

    def get_encoder_counts(self):
        values = self.execute_array('e')
        if len(values) not in [2,4]:
            print "Encoder count was not 2 or 4 for 4wd"
            raise SerialException
            return None
        else:

修改完後，將arduino的固件更新，就可以啓動4驅底盤控制了，要注意的時候要同時打開上位機和arduino上的4驅開關，如果是使用2驅的代碼，也要記得關掉4驅的開關。
3.啓動4驅底盤控制
現在執行如下命令可以啓動4驅底盤控制

roslaunch diego_nav diego_arduino_run.launch 

現在我們可以通過配套的ROS APP連接Diego#進行控制
首先創建一個新的ROS機器人連接，設置相應的ROS Master ip，和cmd_vel主題。