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 showed 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:​ #

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​ #

IMU Parameters Documentation​ #

Parameter	Type	Range Min	Range Max	Default	Options
filtered_ahrs_publish_rate	int	0	200	100	–
filtered_imu_publish_rate	int	0	4000	1000	–
filtered_imu_fusion_gain	double	0	1	0.5	–
enable_tf_publisher	bool	–	–	true	–
operation_mode	string	–	–	AHRS-	Read Description
enable_magnetometer_publisher	bool	–	–	true	–
enable_filtered_ahrs_publisher	bool	–	–	true	–
enable_filtered_imu_publisher	bool	–	–	true	–
enable_filtered_ahrs_acc_gravity_compensation	bool	–	–	false	–
ahrs_fusion_rate	int	0	250	200	–
imu_fusion_rate	int	0	2500	2000	–
enable_startup_zero_quaternion	bool	–	–	true	–
imu_acc_cutoff_frequency	double	0	1000	5.0	–
imu_acc_filter_order	int	1	2	2	–
imu_gyro_cutoff_frequency	double	0	1000	5.0	–
imu_gyro_filter_order	int	1	2	2	–
ahrs_acc_cutoff_frequency	double	0	1000	5.0	–
ahrs_acc_filter_order	int	1	2	2	–
ahrs_gyro_cutoff_frequency	double	0	1000	5.0	–
ahrs_gyro_filter_order	int	1	2	2	–
ahrs_mag_cutoff_frequency	double	0	1000	5.0	–
ahrs_mag_filter_order	int	1	2	2	–
topic_publisher_qos	string	–	–	reliable	besteffort, reliable

Detailed Parameter Descriptions​ #

IMU Parameters Documentation​ #

• filtered_ahrs_publish_rate: This value changes the publish rate of the filtered AHRS data, allowing adjustments between 0 and 200 Hz.
• filtered_imu_publish_rate: This value changes the publish rate for raw IMU data, with adjustable rates from 0 to 4000 Hz to match the requirements of different applications.
• filtered_imu_fusion_gain: Adjusts the fusion gain for combining sensor data within the IMU, with a scale from 0 to 1 to fine-tune the balance between raw sensor inputs and algorithmically processed outputs.
• enable_tf_publisher: When enabled, publishes a transformation frame (tf) specific to the filtered IMU data, useful for applications requiring precise spatial orientation.
• operation_mode: Allows users to select the operational mode of the sensors:
  • AHRS+ (NDOF in old version): Absolute orientation with fast magnetic calibration.
  • AHRS (NDOF_FMC_OFF in old version): Absolute orientation without fast magnetic calibration.
  • AHRS- (IMUPLUS in old version): Relative orientation with the magnetometer disabled.
• enable_magnetometer_publisher: When enabled, this setting activates the publisher for the magnetometer, allowing the transmission of magnetometer data.
• enable_filtered_ahrs_publisher: This setting, when enabled, activates the publisher for filtered Attitude and Heading Reference System (AHRS) data.
• enable_filtered_imu_publisher: Enabling this setting will activate the publisher for filtered Inertial Measurement Unit (IMU) data.
• enable_filtered_ahrs_acc_gravity_compensation: Enables gravity compensation for the accelerometer data within the filtered AHRS data, aiding in more accurate orientation calculations.
• ahrs_fusion_rate: Adjusts the input/output rate of the AHRS data, with a maximum limit of 250 Hz, allowing for faster or slower data processing based on the needs.
• imu_fusion_rate: Similar to the AHRS fusion rate, this adjusts the IO rate for the IMU data but with a higher maximum limit of 2500 Hz, accommodating more rapid data processing requirements.
• enable_startup_zero_quaternion: If enabled, resets the quaternion values to zero upon system startup, useful for calibration or when consistent initial conditions are necessary.
• imu_acc_cutoff_frequency: Sets the cutoff frequency for the IMU accelerometer, allowing fine-tuning between 0 and 1000 Hz for signal filtering.
• imu_acc_filter_order: Configures the filter order for the IMU accelerometer, with valid options of 1 or 2 for enhanced data smoothing.
• imu_gyro_cutoff_frequency: Specifies the cutoff frequency for the IMU gyroscope, adjustable between 0 and 1000 Hz for noise reduction.
• imu_gyro_filter_order: Configures the filter order for the IMU gyroscope, with valid options of 1 or 2 to control data processing depth.
• ahrs_acc_cutoff_frequency: Sets the cutoff frequency for the AHRS accelerometer, enabling precise filtering between 0 and 1000 Hz.
• ahrs_acc_filter_order: Defines the filter order for the AHRS accelerometer, supporting options of 1 or 2 for customized data smoothing.
• ahrs_gyro_cutoff_frequency: Adjusts the cutoff frequency for the AHRS gyroscope, allowing filtering adjustments between 0 and 1000 Hz.
• ahrs_gyro_filter_order: Configures the filter order for the AHRS gyroscope, with valid options of 1 or 2 for tailored data refinement.
• ahrs_mag_cutoff_frequency: Specifies the cutoff frequency for the AHRS magnetometer, adjustable between 0 and 1000 Hz for enhanced signal quality.
• ahrs_mag_filter_order: Configures the filter order for the AHRS magnetometer, supporting options of 1 or 2 to optimize data accuracy.
• topic_publisher_qos: Defines the Quality of Service (QoS) level for all topic publishers. Options include:
  • besteffort: Prioritizes low-latency data delivery, allowing for some data loss.
  • reliable: Ensures reliable data delivery by retrying transmission until acknowledged.

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

Downloads (OLVX™-IMU-X01-G2)​ #

Type	Format	Version	Link
3D Models
	STP	1.0	download

Mechanical Details​ #

(OLVX™-IMU-X01-G1)​ #

(OLVX™-IMU-X01-G2)​ #