# 6.2.3. 在 DrRobotIMUGPSDCM.dll 內的 DCM 功能

DrRobotIMUGPSDCM.cs 檔案中描述了 DrRobotIMUGPSDCM.dll 中提供的所有函數。請注意，我們現在是使用機載控制器來做機器人方位估算。你可以用自己的演算法，依據 IMU 原始數據和 GPS 感測器數據來做方位的估算。以下是清單：

```
/// </summary>
/// <param name="dir">left motor direction, if left motor go forward, encoder value is increasing, dir = 1, otherwise, dir = ‐1</param>
/// <param name="wheelCnt">wheel spin one circle, encoder count number</param>
/// <param name="wheelR">wheel Radius</param>
/// <param name="wheelDis"> distance between left/right wheel</param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern int SetEncoderParameter(int dir, int wheelCnt, double wheelR, double wheelDis);
```

```
/// <summary>
/// this function is for GPS sensor data update
/// </summary>
/// <param name="cog">cog ‐‐ course over ground, radian, ‐pI ~ PI</param>
/// <param name="vog">vog ‐‐ velocity over ground, unit: m/s</param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern void UpdateGPS(double cog, double vog);
```

```
/// <summary>
/// this function will estimate position based on latest encoder information
/// </summary>
/// <param name="leftEncoder">current left encoder reading</param>
/// <param name="rightEncoder">current right encoder reading</param>
/// <param name="estPos">pointer to current position estimation, estPos[0] ‐‐ E, estPos[1] ‐‐ N, estPos[2] ‐‐ Orientation(Yaw)</param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern int EncoderEstimate(int leftEncoder, int rightEncoder, double* estPos);
```

```
/// <summary>
/// this function will use GPS latitude and longitude reading to update estimated position
/// </summary>
/// <param name="latitude">unit: degree</param>
/// <param name="longitude">unit : degree</param>
/// <param name="estPos">pointer to current position estimation, estPos[0] ‐‐ E, estPos[1] ‐‐ N, estPos[2] ‐‐ Orientation(Yaw)</param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern int GPSUpdatePosition(double latitude, double longitude,double* estPos);
```

```
/// <summary>
/// these 5 functions are used for coordinate transform, this function must be called first
/// GPS (latitude, longitude, altitude) <‐‐‐> ECEF (XYZ) <‐‐‐‐> Navigation ENU (E,N,U)
/// we need first set reference latitude, longitude (ENU (0,0,0) point
///
/// </summary>
/// <param name="latitude"> unit: degree</param>
/// <param name="longitude"> unit: degree</param>
/// <param name="altitude">0</param>
/// <param name="xyzr">reference point in ECEF(XYZ)</param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern void SetRefXYZ(double latitude, double longitude,double altitude,double* xyzr);
```

```
/// <summary>
/// this function is for LLH to XYZ
/// </summary>
/// <param name="lat">unit: degree</param>
/// <param name="lng">unit: degree</param>
/// <param name="h">0</param>
/// <param name="XYZ">position in ECEF</param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern void LLH2XYZ(double lat,double lng,double h, double* XYZ);
```

```
/// <summary>
/// this function is for XYZ to ENU
/// </summary>
/// <param name="XYZr">reference point XYZ</param>
/// <param name="XYZ">point XYZ(ECEF)</param>
/// <param name="ENU">point in ENU</param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern void XYZ2ENU(double* XYZr, double* XYZ, double* ENU);
```

```
//
//
//
// setENU[2] ‐‐U 0 forced as "0" in function
/// <summary>
/// this function is ENU 2 XYZ
/// setENU[0] ‐ E
///	setENU[1] ‐‐ N
///	setENU[2] ‐‐U 0 forced as "0"
/// </summary>
/// <param name="setENU"></param>
/// <param name="calXYZ"></param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern void ENU2XYZ(double* setENU, double* calXYZ);
```

```
//
//
/// <summary>
/// XYZ to LLH
/// latitude, longitude unit: degree, altitude = 0
/// </summary>
/// <param name="XYZ"></param>
/// <param name="calLLH"></param> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError =  true)]  static unsafe extern void XYZ2LLH(double* XYZ, double* calLLH);
```

```
/// <summary>
/// this function will calculate the distance between two points
/// (latitude1, longitude1) to (latitude0, longitude0)
/// </summary>
/// <param name="latitude1"></param>
/// <param name="longitude1"></param>
/// <param name="latitude0"></param>
/// <param name="longitude0"></param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern double DistanceLL(double latitude1, double longitude1, double latitude0, double longitude0);
```

```
/// <summary>
/// this function will calculate the heading direction from (latitude1, longitude1) to (latitude2, longitude2)
/// the return value is in radian, ‐PI ~ PI, 0 is point to north, PI/2 is point to East
/// </summary>
/// <param name="latitude1"></param>
/// <param name="longitude1"></param>
/// <param name="latitude2"></param>
/// <param name="longitude2"></param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern double BearingToLL(double latitude1, double longitude1, double latitude2, double longitude2);
```

```
/// <summary>
/// this function will estimate driving direction, based on current estimated position and preset path
/// the preset path is defined by (startENU) ‐‐‐> endENU
/// the return value is robot driving direction
/// </summary>
/// <param name="estPos"></param>
/// <param name="distanceError"></param>
/// <param name="startDir"></param>
/// <param name="heading"></param>
/// <param name="startENU"></param>
/// <param name="endENU"></param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern double EstimateDrvDir(double* estPos, double distanceError,double startDir, double heading, double* startENU, double* endENU);
```

```
/// <summary>
/// this function will set driving parameters
///
/// </summary>
/// <param name="targetTH">distance 2 target threshold</param>
/// <param name="pathTH">distance 2 preset path threshold</param>
/// <param name="angleTH">unit radian, set the minimum angle for robot adjustment</param>
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern void SetDrvParameter(double targetTH, double pathTH, double angleTH);
```

```
//
/// <summary>
/// this function will return distance between current XYZ and preset path(startXYZ‐ ‐endXYZ)
/// </summary>
/// <param name="curXYZ"></param>
/// <param name="startXYZ"></param>
/// <param name="endXYZ"></param>
/// <returns></returns> 
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static unsafe extern double Distance2Path(double* curXYZ, double* startXYZ, double* endXYZ);
```

```
/// <summary>
/// this function is setting GPS position estimate parameter
/// position = encoder_position + kp *(gps_position ‐ encoder_position)
/// </summary>
/// <param name="kp">now we set it as 0.5, if ground is very slip, you can trust GPS more, set as 0.8 or 1</param>
/// <param name="diffTH"> if abs( distance(gps_position ‐ pre_gps_position)‐ distance(encoder_position‐ pre_encoder_position) ) > diffTH, we did not use GPS estimation</param>
[DllImport("DrRobotIMUGPSDCM.dll", SetLastError = true)]
static extern void SetGPSPositionUpdateParameter(double kp, double diffTH);
```


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