1) olixSense™ IMU

Versions​ #

Product Name	Type	Generation	Product Number
olixSense X1	USB-C Dual Redundant	01	OIMU-X1S-9DOF
olixSense X1	USB-C Dual Redundant	02	OIMU-X1S-9DOF2
olixSense X1 Pro	USB-C Tripple Redundant	01	OIMU-X1P-9DOF

Product Name	Type	Generation	Product Number
olixSense E1 Pro	Ethernet Tripple-Redundant	01	OIMU-E1P-9DOF

OLVX™-IMU-X01-Gen1 (Deprecated)	OLVX™IMU-X01-Gen2 (Deprecated)
OLVX™IMU-X01-Pro	OLVX™IMU-E01-Pro

Sensor Details​ #

The OlixSense™ is a IMU sensor designed for use in robotics and other applications that require precise attitude and heading information. It uses a redundant 9 degree-of-freedom (DOF) sensor array, which provides accurate and stable measurements of orientation and angular velocity with a 3-axis gyroscope, 3-axis accelerometer, and 3-axis magnetometer.

Datasheet​ #

Download

Sensor System Architecture​ #

Components​ #

• 3-axis gyroscope: The IMU module features a 3-axis gyroscope that provides accurate and reliable angular rate data in all three dimensions (x, y, z). This allows you to measure the orientation of the IMU module with respect to a fixed reference frame, and to track the changes in orientation over time.
• 3-axis accelerometer: The IMU module also features a 3-axis accelerometer that provides accurate and reliable acceleration data in all three dimensions (x, y, z). This allows you to measure the linear acceleration of the IMU module with respect to a fixed reference frame, and to track the changes in linear acceleration over time.
• 3-axis magnetometer: The IMU module also features a 3-axis magnetometer that provides accurate and reliable magnetic field data in all three dimensions (x, y, z). This allows you to measure the magnetic field of the IMU module with respect to a fixed reference frame, and to track the changes in magnetic field over time.

3D Coordinate System #

OLVX™-IMU-X01-Gen1 (Deprecated)	OLVX™IMU-X01-Gen2 (Deprecated)
OLVX™IMU-X01-Pro	OLVX™IMU-E01-Pro

Key Features​ #

• 9-degree-of-freedom orientation and acceleration measurements
• Maximum data rate of 1000 Hz
• Attitude and heading reference system (AHRS)
• Compact and lightweight design
• USB Type-C and Ethernet over USB communication options
• Out-of-the-box ROS1 (via bridge) & ROS2 (native) support

Technical Specifications​ #

OLVX™ IMU Technical Specifications​ #

General Specifications​ #

Part Number	OLVX™-IMU-U02X9D
Connection Interface	USB Type-C
Communication Protocol	ROS 1&2 (Virtual Ethernet / IPV4)
Gyroscope Range	± 2000 deg/sec
Accelerometer Range	± 16 g
Magnetometer Range	± 4 gauss
Sample Rate	1000 Hz
Performance Metrics	Covariance Matrix
Native ROS Messages	sensor_msgs/Imu, sensor_msgs/Temperature
Operating Temperature	0°C ~ 55°C

System Performance​ #

AHRS Accuracy	Specification
Roll, Pitch (Static, AHRS Mode, Max Rate 100 Hz)	0.42°
Roll, Pitch (Dynamic, AHRS Mode, Max Rate 100 Hz)	0.85°
Roll, Pitch (Dynamic, IMU Mode, Max Rate 2000 Hz)	1.05°
Heading (Static, AHRS Mode, Max Rate 100 Hz)	±1.2°
Heading (Dynamic, AHRS Mode, Max Rate 100 Hz)	±2.8°
Heading (Dynamic, IMU Mode, Max Rate 2000 Hz)	±0.8° ±0.06 dps

IMU Sensor Details​ #

Specification	Accelerometer	Gyroscope	Magnetometer
Range	±4g, ±8g, ±16g	±250°/s, ±500°/s, ±1000°/s	±1300 µT
Resolution	16-bit or 0.06 mg/LSB	16-bit or 0.004 dps/LSB	16-bit
Sensitivity	2048 LSB/g @ ±16g	262.1 LSB/dps @ ±125°/sec	±0.3 µT
Sensitivity Tolerance	±4% @ Ta = 25°C, gFS2g	±3% @ Ta = 25°C, RFS2000	±0.03% (API compensated)
Zero-rate Offset	±20 mg	±0.5 dps	–
Output Noise Density	160 µg/√Hz	0.008 dps/√Hz	–
Zero-g Offset (x, y, z)	±150 mg (gFS2g, Ta=25°C)	±3 dps	–
Nonlinearity	0.5% FS @ Ta=25°C	0.01% FS	1.2% FS

Interface Connection​ #

Parameter	Specification
Connector	USB Type-C
Communications Interface	Ethernet Over USB
Output Data Rate	1-2000 Hz (Raw and Fused Data)
Protocols (DDS)	rmw_fastrtps_cpp, rmw_cyclonedds_cpp (Upgradeable to rmw_connext_cpp & rmw_zenoh)

Physical and Electrical Characteristics​ #

Parameter	Specification
Weight	32 g
Size	40.0 mm x 40.0 mm x 10.0 mm
Power Consumption	0.9 W (Typical), 1.8 W (Max)
Operating Voltage	4.6 to 5.5 VDC (USB PD 2.0 Standard)
Operating Temperature	0°C to 85°C
Interface LEDs	3x (Heartbeat, User, System)

IMU Noise and Random Walk Parameters​ #

Parameter	AHRS	IMU
Accelerometer Noise Density	150 µg/√Hz	180 µg/√Hz
Accelerometer Random Walk	0.04 m/s/√hr	0.05 m/s/√hr
Gyroscope Noise Density	0.03 °/s/√Hz	0.01 °/s/√Hz
Gyroscope Random Walk	1.5 °/hr/√Hz	1.0 °/hr/√Hz

Demo​ #

Unboxing​ #

Setup and Test:​ #

1. Follow the Quick Start Guide for Olive Robotics robot modules to connect the device and start using it.
2. For more information about the IMU setup and user interface, refer to the demonstration below:
3. When the IMU module is correctly connected to your system, you can check that the expected ros topics are present.
   • On your host PC run:
     • ros2 topic list
   • The following ROS topics should be shown:

The number id001 is your device’s default namespace.

By default, the magnetometer is disabled, making the sensor output relative. To enable the magnetometer and perform calculations based on magnetometer calibration, set the operation_mode parameter to AHRS+ / AHRS

4. All topics shown are publishers, meaning that they publish data to the ROS network. In the command line interface you can verify that they are in fact publishing data using for example:
   • ros2 topic echo /olive/imu/id001/filtered_ahrs
5. Visualize the data using:
   1. Embedded Web Interface (https://olive-robotics.com/docs2/olive-embedded-web-based-gui/)
   2. rqt (https://olive-robotics.com/docs2/ros-rqt-interface/)
   3. rviz2 (https://olive-robotics.com/docs2/rviz-2/).
6. Visualize the data and change the parameters like IP, Topic Name, etc using the embedded web interface. You just need to open your browser on your host computer and enter the IP address of the device. If you didn’t change the default IP address, then it must be 192.168.7.100.

ROS Topics and Services​ #

Topics #

Services​ #

Service Name	Service Type	Type	Description
/setBias	std_srvs/srv/Trigger	Service	Calibrating the sensor’s bias offset values
/setZeroQuaternion	std_srvs/srv/Trigger	Service	Resetting the sensor’s rotation axis
/setZeroPose	std_srvs/srv/Trigger	Service	Resetting the sensor’s position estimation

Calibrating the sensor’s bias offset values: #

By calling the setBias service or triggering it from the GUI, the sensor will collect bias values to minimize the zero offset. During this process, please ensure that the sensor remains completely stable and is not moving. It is also important to call the service when the sensor is placed in the correct Orientation: the Olive logo facing up and the four screw holes facing down.

Resetting the sensor’s rotation axis:​ #

The gain effect of the low-pass filter:​ #

Advanced Settings​ #

The device allows certain parameters to be changed at runtime. To get an overview of all changeable parameters use 

ros2 param list

To change a parameter use 

ros2 param set /dcm_imu <parameter> <new_value>

IMU Parameters #

​

Name	Description	Type	Default Value	Range / Options
operation_mode	Change sensor operation mode: AHRS-, AHRS, AHRS+.	string	AHRS-	AHRS- | AHRS | AHRS+
enable_tf_publisher	Publish a dedicated tf with respect to filtered IMU data.	bool	true	–
enable_fusion_publisher	Activate the fusion data publisher.	bool	true	–
enable_linear_acc_publisher	Activate the linear gravity-compensated accelerometer publisher.	bool	true	–
enable_startup_zero_quaternion	Reset quaternion on system startup.	bool	true	–
enable_ahrs_publisher	Activate the filtered AHRS data publisher.	bool	true	–
ahrs_publish_rate	Publish rate for filtered AHRS data.	int	100	[0, 100] Hz
enable_temperature_publisher	Activate the temperature data publisher.	bool	true	–
enable_twist_publisher	Activate the twist (velocity) data publisher.	bool	true	–
imu_acc_cutoff_frequency	IMU accelerometer cutoff frequency (0 disables).	double	100.0	[0, 500] Hz
imu_acc_ema_gain	EMA gain for IMU accelerometer (0 disables).	double	0.9	[0, 1]
imu_gyro_cutoff_frequency	IMU gyroscope cutoff frequency (0 disables).	double	100.0	[0, 500] Hz
imu_gyro_ema_gain	EMA gain for IMU gyroscope (0 disables).	double	0.9	[0, 1]
ahrs_acc_cutoff_frequency	AHRS accelerometer cutoff frequency (0 disables).	double	100.0	[0, 500] Hz
ahrs_acc_ema_gain	EMA gain for AHRS accelerometer (0 disables).	double	0.5	[0, 1]
ahrs_gyro_cutoff_frequency	AHRS gyroscope cutoff frequency (0 disables).	double	100.0	[0, 500] Hz
ahrs_gyro_ema_gain	EMA gain for AHRS gyroscope (0 disables).	double	0.5	[0, 1]
ahrs_mag_cutoff_frequency	AHRS magnetometer cutoff frequency (0 disables).	double	100.0	[0, 500] Hz
ahrs_mag_ema_gain	EMA gain for AHRS magnetometer (0 disables).	double	0.5	[0, 1]
fusion_gain	Fusion gain for sensor data fusion.	double	0.1	[0, 1]
fusion_publish_rate	Publish rate of fusion data.	int	500	[0, 1000] Hz
gyro_zero_cutoff_threshold	Gyro zero cutoff threshold (0 disables).	double	0.005	[0, 1]
linear_acc_zero_cutoff_threshold	Linear acceleration zero cutoff threshold (0 disables).	double	0.2	[0, 1]
topic_publisher_qos	QoS type for all topic publishers.	string	reliable	besteffort | reliable

Detailed Parameter Descriptions #

​operation_mode
Change the internal sensor operation mode: AHRS+ for absolute orientation with fast magnetic calibration, AHRS for absolute orientation without fast magnetic calibration, AHRS- for relative orientation with the magnetometer disabled.
Options: AHRS- | AHRS | AHRS+

enable_tf_publisher
Enabling this will publish a dedicated transformation (tf) frame with respect to the filtered IMU data, useful for applications requiring precise spatial orientation.

enable_fusion_publisher
Enabling this will activate the fusion data publisher.

enable_linear_acc_publisher
Enabling this will activate the linear, gravity-compensated accelerometer data publisher.

enable_startup_zero_quaternion
Enabling this will reset the quaternion values to zero upon system startup for consistent initial conditions.

enable_ahrs_publisher
Enabling this will activate the filtered AHRS (Attitude and Heading Reference System) data publisher.

ahrs_publish_rate
Sets the publish rate for the filtered AHRS data in Hz.
Range: [0, 100]

enable_temperature_publisher
Enabling this will activate the temperature data publisher.

enable_twist_publisher
Enabling this will activate the twist (angular and linear velocity) data publisher.

imu_acc_cutoff_frequency
Sets the cutoff frequency for the IMU accelerometer. A value of zero disables the cutoff filter.
Range: [0, 500] Hz

imu_acc_ema_gain
Sets the exponential moving average (EMA) gain for the IMU accelerometer. A value of zero disables EMA filtering.
Range: [0, 1]

imu_gyro_cutoff_frequency
Sets the cutoff frequency for the IMU gyroscope. A value of zero disables the cutoff filter.
Range: [0, 500] Hz

imu_gyro_ema_gain
Sets the exponential moving average (EMA) gain for the IMU gyroscope. A value of zero disables EMA filtering.
Range: [0, 1]

ahrs_acc_cutoff_frequency
Sets the cutoff frequency for the AHRS accelerometer. A value of zero disables the cutoff filter.
Range: [0, 500] Hz

ahrs_acc_ema_gain
Sets the exponential moving average (EMA) gain for the AHRS accelerometer. A value of zero disables EMA filtering.
Range: [0, 1]

ahrs_gyro_cutoff_frequency
Sets the cutoff frequency for the AHRS gyroscope. A value of zero disables the cutoff filter.
Range: [0, 500] Hz

ahrs_gyro_ema_gain
Sets the exponential moving average (EMA) gain for the AHRS gyroscope. A value of zero disables EMA filtering.
Range: [0, 1]

ahrs_mag_cutoff_frequency
Sets the cutoff frequency for the AHRS magnetometer. A value of zero disables the cutoff filter.
Range: [0, 500] Hz

ahrs_mag_ema_gain
Sets the exponential moving average (EMA) gain for the AHRS magnetometer. A value of zero disables EMA filtering.
Range: [0, 1]

fusion_gain
Adjusts the fusion gain used for combining sensor data. A smaller value gives slower, more stable fusion, while a larger value makes it more responsive.
Range: [0, 1]

fusion_publish_rate
Sets the publish rate for fusion data in Hz.
Range: [0, 1000]

gyro_zero_cutoff_threshold
Specifies a zero cutoff threshold for the gyroscope output. Values below this threshold are considered noise and set to zero. A value of zero disables the threshold.
Range: [0, 1]

linear_acc_zero_cutoff_threshold
Specifies a zero cutoff threshold for the linear acceleration output. Values below this threshold are considered noise and set to zero. A value of zero disables the threshold.
Range: [0, 1]

topic_publisher_qos
Defines the Quality of Service (QoS) setting for all topic publishers

Options: besteffort | reliable

reliable: Ensures reliable delivery by retrying transmissions until acknowledged.
besteffort: Prioritizes low-latency delivery, allows some data loss.

---

Notes: #

Ensure consistency between your fusion rate, AHRS rate, and QoS settings depending on your application needs.

Any EMA Gain = 0 or Cutoff Frequency = 0 disables that specific filter.

System​ #

Parameter	Type	Range Min	Range Max	Default	Description
frequency	int	0	10	1	System status publish rate

Downloads #

OLVX™-IMU-X01-G1​ #

Type	Format	Version	Link
3D Models
	STP	1.0	download
	OBJ	1.0	download
CAD Drawings
	DWG	1.0	download
	PDF	1.0	download

OLVX™-IMU-X01-G2​ #

Type	Format	Version	Link
3D Models
	STP	1.0	download

OLVX™IMU-X01-Pro #

Type	Format	Version	Link
3D Models
	STP	1.0	download

Mechanical Details​ #

(OLVX™-IMU-X01-G1)​ #

(OLVX™-IMU-X01-G2)​ #