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【Landzo C1试用体验】+ 第四篇 ☞头部运动追踪第一步：MPU6050控制舵机

        做飞思卡尔智能车比赛的时候看到平衡组的用过这个6050，当时就很感兴趣，一直想玩一下。
        后来我就想这个东西是不是可以用来做头部运动的追踪，没想到经过一天的查资料，在别的论坛这些早都被玩过了。
        经过一天的学习，我实现了我想要的功能，完整的头追要等开学以后才能发帖，我回老家只带了这么点东西回来。
       下面进入正题，
        1.什么是MPU6050?
                6050.png
        MPU6050是一种非常流行的空间运动传感器芯片，可以获取器件当前的三个加速度分量和三个旋转角速度。由于其体积小巧，功能强大，精度较高，不仅被广泛应用于工业，同时也是航模爱好者的神器，被安装在各类飞行器上驰骋蓝天。
  2.所使用套件中的蓝色舵机简介
         舵机.png
        蓝宙的PDF里已经给的很全了，这里不做赘述。
  3.接线示意图
         接线.png
        另外的舵机按照上一节图片中相应去接就可以了。
  4.俯仰角和横滚角
         关于两个角度.png 默认串口显示.png 坐标系.png
        通过阅读上述资料，以及具体的实验观察现象，其对应关系为pitch（俯仰角）和roll（横滚角）具体方法是使用卡尔曼滤波算法中的例程《MPU6050》，这个例程我会上传到附件中。把程序下载到arduino，再打开串口监视器，（这里注意要把波特率修改为115200，和程序中的设定同步，不然你看到的将会是乱码），我们就可以看到第二张图中定义的几个量了。如果需要显示acc和gyro则把程序中的0改为1。
  5.具体实现代码
        通过对第四节和第二节的学习，我们知道舵机的角度是0~180度，而我们通过串口监视器观察到的roll大概是在-90度~90度之间。为了实现同步，在舵机赋值的时候我们把roll加个90再附进去就差不多了。手上硬件全的话，你们就根据实际情况矫正的精准一些，我这里暂时没有这个必要了。我在附件中上传了实验效果的视频，有兴趣的同学可以查看。再添加舵机语句的时候要注意放的位置，不要放到某一个if判断的末尾。添加的语句已经标注为红色。
  1. /* Copyright (C) 2012 Kristian Lauszus, TKJ Electronics. All rights reserved.

  3. This software may be distributed and modified under the terms of the GNU
  4. General Public License version 2 (GPL2) as published by the Free Software
  5. Foundation and appearing in the file GPL2.TXT included in the packaging of
  6. this file. Please note that GPL2 Section 2[b] requires that all works based
  7. on this software must also be made publicly available under the terms of
  8. the GPL2 ("Copyleft").

  10. Contact information
  11. -------------------

  13. Kristian Lauszus, TKJ Electronics
  14. Web      :  http://www.tkjelectronics.com
  15. e-mail   :  kristianl@tkjelectronics.com
  16. */
  17. #include
  18. #include
  19. #include // Source: https://github.com/TKJElectronics/KalmanFilter

  21. Servo servo_pin_10;

  23. #define RESTRICT_PITCH // Comment out to restrict roll to ±90deg instead - please read: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf

  25. Kalman kalmanX; // Create the Kalman instances
  26. Kalman kalmanY;

  28. /* IMU Data */
  29. double accX, accY, accZ;
  30. double gyroX, gyroY, gyroZ;
  31. int16_t tempRaw;

  33. double gyroXangle, gyroYangle; // Angle calculate using the gyro only
  34. double compAngleX, compAngleY; // Calculated angle using a complementary filter
  35. double kalAngleX, kalAngleY; // Calculated angle using a Kalman filter

  37. uint32_t timer;
  38. uint8_t i2cData[14]; // Buffer for I2C data

  40. // TODO: Make calibration routine

  42. void setup() {
  43.    servo_pin_10.attach(10);
  44.   Serial.begin(115200);
  45.   Wire.begin();
  46. #if ARDUINO >= 157
  47.   Wire.setClock(400000UL); // Set I2C frequency to 400kHz
  48. #else
  49.   TWBR = ((F_CPU / 400000UL) - 16) / 2; // Set I2C frequency to 400kHz
  50. #endif

  52.   i2cData[0] = 7; // Set the sample rate to 1000Hz - 8kHz/(7+1) = 1000Hz
  53.   i2cData[1] = 0x00; // Disable FSYNC and set 260 Hz Acc filtering, 256 Hz Gyro filtering, 8 KHz sampling
  54.   i2cData[2] = 0x00; // Set Gyro Full Scale Range to ±250deg/s
  55.   i2cData[3] = 0x00; // Set Accelerometer Full Scale Range to ±2g
  56.   while (i2cWrite(0x19, i2cData, 4, false)); // Write to all four registers at once
  57.   while (i2cWrite(0x6B, 0x01, true)); // PLL with X axis gyroscope reference and disable sleep mode

  59.   while (i2cRead(0x75, i2cData, 1));
  60.   if (i2cData[0] != 0x68) { // Read "WHO_AM_I" register
  61.     Serial.print(F("Error reading sensor"));
  62.     while (1);
  63.   }

  65.   delay(100); // Wait for sensor to stabilize

  67.   /* Set kalman and gyro starting angle */
  68.   while (i2cRead(0x3B, i2cData, 6));
  69.   accX = (i2cData[0] << 8) | i2cData[1];
  70.   accY = (i2cData[2] << 8) | i2cData[3];
  71.   accZ = (i2cData[4] << 8) | i2cData[5];

  73.   // Source: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf eq. 25 and eq. 26
  74.   // atan2 outputs the value of -π to π (radians) - see http://en.wikipedia.org/wiki/Atan2
  75.   // It is then converted from radians to degrees
  76. #ifdef RESTRICT_PITCH // Eq. 25 and 26
  77.   double roll  = atan2(accY, accZ) * RAD_TO_DEG;
  78.   double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
  79. #else // Eq. 28 and 29
  80.   double roll  = atan(accY / sqrt(accX * accX + accZ * accZ)) * RAD_TO_DEG;
  81.   double pitch = atan2(-accX, accZ) * RAD_TO_DEG;
  82. #endif

  84.   kalmanX.setAngle(roll); // Set starting angle
  85.   kalmanY.setAngle(pitch);
  86.   gyroXangle = roll;
  87.   gyroYangle = pitch;
  88.   compAngleX = roll;
  89.   compAngleY = pitch;

  91.   timer = micros();
  92. }

  94. void loop() {
  95.   /* Update all the values */
  96.   while (i2cRead(0x3B, i2cData, 14));
  97.   accX = ((i2cData[0] << 8) | i2cData[1]);
  98.   accY = ((i2cData[2] << 8) | i2cData[3]);
  99.   accZ = ((i2cData[4] << 8) | i2cData[5]);
  100.   tempRaw = (i2cData[6] << 8) | i2cData[7];
  101.   gyroX = (i2cData[8] << 8) | i2cData[9];
  102.   gyroY = (i2cData[10] << 8) | i2cData[11];
  103.   gyroZ = (i2cData[12] << 8) | i2cData[13];


  106.   double dt = (double)(micros() - timer) / 1000000; // Calculate delta time
  107.   timer = micros();

  109.   // Source: http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf eq. 25 and eq. 26
  110.   // atan2 outputs the value of -π to π (radians) - see http://en.wikipedia.org/wiki/Atan2
  111.   // It is then converted from radians to degrees
  112. #ifdef RESTRICT_PITCH // Eq. 25 and 26
  113.   double roll  = atan2(accY, accZ) * RAD_TO_DEG;
  114.   double pitch = atan(-accX / sqrt(accY * accY + accZ * accZ)) * RAD_TO_DEG;
  115. #else // Eq. 28 and 29
  116.   double roll  = atan(accY / sqrt(accX * accX + accZ * accZ)) * RAD_TO_DEG;
  117.   double pitch = atan2(-accX, accZ) * RAD_TO_DEG;
  118. #endif

  120.     servo_pin_10.write(roll+ 90);

  122.   double gyroXrate = gyroX / 131.0; // Convert to deg/s
  123.   double gyroYrate = gyroY / 131.0; // Convert to deg/s

  125. #ifdef RESTRICT_PITCH
  126.   // This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
  127.   if ((roll < -90 && kalAngleX > 90) || (roll > 90 && kalAngleX < -90)) {
  128.     kalmanX.setAngle(roll);
  129.     compAngleX = roll;
  130.     kalAngleX = roll;
  131.     gyroXangle = roll;
  132.   } else
  133.     kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter

  135.   if (abs(kalAngleX) > 90)
  136.     gyroYrate = -gyroYrate; // Invert rate, so it fits the restriced accelerometer reading
  137.   kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt);
  138. #else
  139.   // This fixes the transition problem when the accelerometer angle jumps between -180 and 180 degrees
  140.   if ((pitch < -90 && kalAngleY > 90) || (pitch > 90 && kalAngleY < -90)) {
  141.     kalmanY.setAngle(pitch);
  142.     compAngleY = pitch;
  143.     kalAngleY = pitch;
  144.     gyroYangle = pitch;
  145.   } else
  146.     kalAngleY = kalmanY.getAngle(pitch, gyroYrate, dt); // Calculate the angle using a Kalman filter

  148.   if (abs(kalAngleY) > 90)
  149.     gyroXrate = -gyroXrate; // Invert rate, so it fits the restriced accelerometer reading
  150.   kalAngleX = kalmanX.getAngle(roll, gyroXrate, dt); // Calculate the angle using a Kalman filter
  151. #endif

  153.   gyroXangle += gyroXrate * dt; // Calculate gyro angle without any filter
  154.   gyroYangle += gyroYrate * dt;
  155.   //gyroXangle += kalmanX.getRate() * dt; // Calculate gyro angle using the unbiased rate
  156.   //gyroYangle += kalmanY.getRate() * dt;

  158.   compAngleX = 0.93 * (compAngleX + gyroXrate * dt) + 0.07 * roll; // Calculate the angle using a Complimentary filter
  159.   compAngleY = 0.93 * (compAngleY + gyroYrate * dt) + 0.07 * pitch;

  161.   // Reset the gyro angle when it has drifted too much
  162.   if (gyroXangle < -180 || gyroXangle > 180)
  163.     gyroXangle = kalAngleX;
  164.   if (gyroYangle < -180 || gyroYangle > 180)
  165.     gyroYangle = kalAngleY;
  166.       

  168.   /* Print Data */
  169. #if 0 // Set to 1 to activate
  170.   Serial.print(accX); Serial.print("t");
  171.   Serial.print(accY); Serial.print("t");
  172.   Serial.print(accZ); Serial.print("t");

  174.   Serial.print(gyroX); Serial.print("t");
  175.   Serial.print(gyroY); Serial.print("t");
  176.   Serial.print(gyroZ); Serial.print("t");

  178.   Serial.print("t");
  179. #endif

  181.   Serial.print(roll); Serial.print("t");
  182.   Serial.print(gyroXangle); Serial.print("t");
  183.   Serial.print(compAngleX); Serial.print("t");
  184.   Serial.print(kalAngleX); Serial.print("t");

  186.   Serial.print("t");

  188.   Serial.print(pitch); Serial.print("t");
  189.   Serial.print(gyroYangle); Serial.print("t");
  190.   Serial.print(compAngleY); Serial.print("t");
  191.   Serial.print(kalAngleY); Serial.print("t");

  193. #if 0 // Set to 1 to print the temperature
  194.   Serial.print("t");

  196.   double temperature = (double)tempRaw / 340.0 + 36.53;
  197.   Serial.print(temperature); Serial.print("t");
  198. #endif

  200.   Serial.print("rn");
  201.   delay(2);
  202. }
  6.应用展望
        如果我手上有两个舵机，那么水平面和竖直面就都可以转动，配合上程序，我们就可以远程的更加人性化的控制摄像头的转动，再把图像显示在头盔中，从而改善现有的监控设备；
        如果我把它装在一辆联网的载具上，就可以远程看到正常人坐在载具中驾驶室的图像，配合上远程操控设备从而时间远程驾驶；
        如果我们在人的鞋子里装上加速度计，通过不同的值来换算成小车的移动速度以及轨迹，再配合上其他传感器，那么，是不是就有可能做出一台跟着人同步走的车？进而我们就可以把书包什么的都丢到车身上，然后我们就可以跑步回家锻炼身体而不是挤公交了。






回帖（29）

antimatter2333

2016-8-9 20:02:08
担心给读者的感觉不够直接，上图，
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  • QQ图片20160809200100.jpg

yuanrk810

2016-9-23 08:32:52
学习了，感谢分享！！
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雷翌仁

2016-10-31 14:33:36
謝謝樓主分享！
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好的够了没有

2016-11-2 22:32:07
我只想把这个装在hmz t1上把它改造成vr，要怎么没实现呢，需要什么硬件和软件呢
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