MPU9250

Measure acceleration, angular rate, and magnetic field, and calculate fusion values such as Euler angles and quaternion along the axes of MPU-9250 sensor

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Libraries:
Simulink Coder Support Package for BeagleBone Blue Hardware / Sensors

Description

Add-On Required: This feature requires the Simulink Coder Support Package for BeagleBone Blue Hardware add-on.

The MPU9250 block reads data from the MPU-9250 sensor that is connected to the hardware. The block has two operation modes: Random and DMP.

The block outputs acceleration, angular rate, and strength of the magnetic field along the axes of the sensor in Random and DMP mode. In DMP mode, the block also outputs the orientation of the sensor as an Euler angle and quaternions. The values emitted in the Random mode are raw values, whereas the values emitted in the DMP mode are calibrated values. The block outputs all the values except for quaternion as a 3-by-1 array of double data type. The quaternion is a 4-by-1 array of double data type.

This illustration shows the default orientation of the x-, y-, and z- axes of the MPU-9250 sensor.

If you simulate a model that contains the MPU9250 block without connecting the hardware, the block outputs zeros. For more information, see Block Produces Zeros or Does Nothing in Simulation.

Note

Before generating code from the MPU9250 block in DMP mode, calibrate the sensor using the calibrateGyro, calibrateAccel, and calibrateMag functions. These functions calibrate the three-axis gyroscope, accelerometer, and magnetometer located inside the sensor.

Ports

Output

Accel — Acceleration including force of gravity along axes of sensor

vector

The Accel port outputs acceleration along the x-, y-, and z- axes of the sensor as a 3-by-1 vector. In DMP mode, the elements of the vector represent calibrated values, whereas in Random mode, the elements represent raw values. The acceleration is measured in m/s² and also includes acceleration due to gravity.

Dependencies

The Accel port is available only when you select the Acceleration (m/s^2) parameter.

Data Types: double

Ang rate — Angle of rotation per second along axes of sensor

vector

The Ang rate port outputs the angle of rotation per second along the x-, y-, and z- axes of the sensor as a 3-by-1 vector. In DMP mode, the elements of the vector represent calibrated values, whereas in Random mode, the elements represent raw values. The angular rate is measured in dps.

Dependencies

The Ang rate port is available only when you select the Angular rate (dps) parameter.

Data Types: double

Mag field — Strength of magnetic field along axes of sensor

vector

The Mag field port outputs the strength of the magnetic field along the x-, y-, and z- axes of the sensor as a 3-by-1 vector. In DMP mode, the elements of the vector represent calibrated values, whereas in Random mode, the elements represent raw values. The magnetic strength is measured in μT.

Dependencies

The Mag field port is available only when you select the Magnetic field (μT) parameter.

Data Types: double

Euler — Sensor orientation given as Euler angles

vector

The Euler port outputs the orientation along the axes of the sensor as a 3-by-1 vector. The elements of the vector represent the orientation using three angular quantities – azimuth (rotation around z- axis), roll (rotation around y- axis), and pitch (rotation around x- axis) of the sensor.

Angular Quantity	Description	Range in Degrees
Azimuth	Angle between y- axis of the sensor and magnetic north	[0, 360]
Roll	Angle between z- axis and x- axis of the sensor	[−90, 90]
Pitch	Angle between z- axis and y- axis of the sensor	[−180, 180]

Dependencies

The Euler port is available only when you set the Operation mode to DMP and select the Euler angles (degrees) parameter.

Data Types: double

Quat — Sensor orientation given as a quaternion

quaternion array

The Quat port outputs the orientation along the w-, x-, y-, and z- axes of the sensor as a 4-by-1 vector. The orientation is measured in quaternion. For more information on quaternions, see quaternion (Robotics System Toolbox).

Dependencies

The Quat port is available only when you set the Operation mode to DMP and select the Quaternion (quaternion) parameter.

Data Types: double

Parameters

Operation mode — Option to output calibrated or raw values

DMP (default) | Random

• DMP — When you set Operation mode to DMP, the sensor operates in 9 degrees of freedom (NDOF) mode. The block outputs calibrated values from the sensor.

  This table lists the block output, measurement unit, dimension, and the axes of the sensor along which each of these outputs are measured.

  Output	Unit	Dimension	Axes
  Acceleration	Meter per second squared (m/s2)	3-by-1	x, y, and z
  Angular rate	degrees per second (dps)	3-by-1	x, y, and z
  Magnetic field	microtesla (μT)	3-by-1	x, y, and z
  Euler angles	degrees per second (dps)	3-by-1	x, y, and z
  Quaternions	Quaternion units	4-by-1	w, x, y, and z

  Note

  Before generating code from the MPU9250 block in DMP mode, calibrate the sensor using the calibrateGyro, calibrateAccel, and calibrateMag functions. These functions run an internal fusion algorithm to configure the range and bandwidth of the sensor with some values.

• Random — When you set Operation mode to Random, the sensor operates outputs raw values from the sensor.

  This table lists the block output, measurement unit, dimension, and the axes of the sensor along which each of these outputs are measured in Random mode.

  Output	Unit	Dimension	Axes
  Acceleration	Meter per second squared (m/s2)	3-by-1	x, y, and z
  Angular rate	degrees per second (dps)	3-by-1	x, y, and z
  Magnetic field	microtesla (μT)	3-by-1	x, y, and z

Sample time — Interval to read values from sensor

0.1 (default) | -1 | any nonnegative value

Specify how often the block read values from the sensor, in seconds. When you specify this parameter as -1, Simulink^® determines the best sample time for the block based on the block context within the model.

Select Outputs

Acceleration (m/s^2) — Acceleration including force of gravity along axes of sensor

on (default) | off

When you select the Acceleration (m/s^2) parameter, the Accel port becomes available. For more information on the Accel port, see Accel.

Angular rate (dps) — Angle of rotation per second along axes of sensor

on (default) | off

When you select the Angular rate (dps) parameter, the Ang rate port becomes available. For more information on the Ang rate port, see Ang rate.

Magnetic field (μT) — Strength of magnetic field along axes of sensor

on (default) | off

When you select the Magnetic field (μT) parameter, the Mag field port becomes available. For more information on the Mag field port, see Mag field.

Data Types: double

Euler angles (degrees) — Orientation along axes of sensor

off (default) | on

When you select the Euler angles (degrees) parameter, the Euler port becomes available. For more information on the Euler port, see Euler.

Dependencies

The Euler angles (degrees) parameter is available only when you set the Operation mode to DMP.

Quaternion (quaternion) — Orientation along axes of sensor

off (default) | on

When you select the Quaternion (quaternion) parameter, the Quat port becomes available. For more information on the Quat port, see Quat.

Dependencies

The Quaternion (quaternion) parameter is available only when you set the Operation mode to DMP

Data Types: double

Advanced Sensor Settings

Accelerometer range — Range of acceleration deviation measured by accelerometer

4G (default) | 2G | 8G | 16G

Select a deviation in the acceleration that the accelerometer can measure. The smaller the accelerometer range is, the more sensitive the readings from the accelerometer are. A small range provides more detailed data, resulting in a more precise reading from the accelerometer.

Dependencies

The Accelerometer range parameter is available only when you set the Operation mode to Random.

Accelerometer bandwidth — Frequency response of accelerometer

1 (default) | 0 | 2 | 3 | 4 | 5 | 6 | 7

Specify the highest frequency at which the accelerometer samples the signal without aliasing by the specified DMP ODR.

Dependencies

The Accelerometer bandwidth parameter is available only when you set the Operation mode to Random.

Gyroscope range — Maximum angular velocity measured by gyroscope

250 dps (default) | 500 dps | 1000 dps | 2000 dps

Specify the maximum angular velocity that the gyroscope can measure per second.

Dependencies

The Gyroscope range parameter is available only when you set the Operation mode to Random.

Gyroscope bandwidth — Frequency response of gyroscope

1 (default) | 0 | 2 | 3 | 4 | 5 | 6 | 7

Specify the highest frequency at which the gyroscope samples the signal without aliasing by the specified DMP ODR.

Dependencies

The Gyroscope bandwidth parameter is available only when you set the Operation mode to Random.

DMP ODR — Rate at which data is sampled

200 (default) | 100 | 50 | 40 | 20 | 10 | 8 | 5 | 4

Specify how many times the sensor measures the values per second.

Dependencies

The DMP ODR parameter is available only when you set the Operation mode to DMP

Data Types: double

Version History

Introduced in R2019a