LSM9DS1 IMU Serial Port ROS Node

Serial Client node in C++ to read IMU data from arduino and embedded systems. It send transforms and sensor_msgs/Imu messages to ROS.

Parameters

Parameter	Function	Default
serial_port	Defines the serial port to use	/dev/ttyUSB0
imu	Defines the name of the imu for tf_broadcaster	imu_link
base	Defines the name of the base for tf_broadcaster	base_link
baudrate	Defines the Baudrate	230400
x_imu_robot	Defines the x position of imu with respect to the base	0.0
y_imu_robot	Defines the y position of imu with respect to the base	0.0
z_imu_robot	Defines the z position of imu with respect to the base	0.0

Examples

The following command has no arguments but default configuration.

foo@bar:~$ rosrun lsm9ds1_imu serial_client

If you want to specify a port where your device is sending messages, set imu name to imu_left_arm and set its position to (0,0,0.2) meters from the base, you can use the next command.

foo@bar:~$ rosrun lsm9ds1_imu serial_client _serial_port:="/dev/ttyACM0" _imu:="imu_left_arm" _z_imu_robot:=.2

Serial Port Format This node reads imu data from serial port with a specific format. You can use this example as template for your program.

Serial port

IMU resolutions and offsets

You have to set resolutions for accelerometer and gyroscope in order to convert raw data to real data. To do this, you have to send a serial port message ending with a \n and it has to be defined as follows:

aRes: accelerometer_resolution
gRes: gyroscope_resolution

Example:

aRes: 0.00006100
gRes: 0.00875000

Similarly, to declare IMU offsets you have to send it as follows:

aOff: accel_offset_x accel_offset_y accel_offset_z
gOff: gyros_offset_x gyros_offset_y gyros_offset_z

Example:

aOff: 0.040 -0.100 -0.010
gOff: -0.050 0.350 -0.730

IMU message definition

Serial Port message has to be ended with a \n and has to be defined as follows:

Imu: q0 q1 q2 q3 gx gy gz gx_var gy_var gz_var ax ay az ax_var ay_var az_var

Name	Definition
q0	w coefficient of quaternion orientation
q1	x coefficient of quaternion orientation
q2	y coefficient of quaternion orientation
q3	z coefficient of quaternion orientation
gx	gyroscope raw value in x
gy	gyroscope raw value in y
gz	gyroscope raw value in z
gx_var	gyroscope covariance in x
gy_var	gyroscope covariance in y
gz_var	gyroscope covariance in z
ax	accelerometer raw value in x
ay	accelerometer raw value in y
az	accelerometer raw value in z
ax_var	accelerometer covariance in x
ay_var	accelerometer covariance in y
az_var	accelerometer covariance in z

Example:

Imu: 0.8504979 0.5120977 0.0719147 0.0960700 -244 2473 -1172 0.00 0.12 0.53 83 -15494 6300 0.00 0.01 0.00