Model submission for Freyja sensor configuration 1 from Robotika

[nkoenig]

Robotika - Freyja

This specifications.md file is a description and proof of virtual model validation for
Robotika's robot Freyja with Sensor Configuration 1. This robot may be launched using
a roslaunch command with the variable name robotika_freyja_sensor_config_1.

Description

Freyja is a four-wheel all-terrain ground vehicle. With weight under 30 kg and its
medium size, Freyja can be transported by a single person as a check-in baggage on an
airplane.

Cost and Scale

Robotika's Freyja has an estimated commercial cost of USD 7,000. It weighs approximately
29.6 kg.

Sensors

Freyja in Sensor Configuration 1 is equipped with forward-looking and backward looking
medium-fps RGB & Depth cameras with wide field of view (Mynte Eye D), four even
wider-field-of-view color cameras looking all around (KAYETON), two planar lidars
(SICK TIM881P), and with other sensors, such as imu combined with a magnetic compass
(CMPS14), an altimeter (Infineon DPS310), a CO2 sensor (MH-Z19B) and in-wheel encoders.

The specifications for these instruments are provided below in
the Validation Links section.

The following specific sensors are declared payloads of this vehicle:

• 2x RGBD camera — Mynt Eye D, modeled by rgbd_camera plugin.
• 2x Planar lidar — SICK TIM881P, modeled by gpu_lidar plugin.
• 4x Monocular camera — KAYETON, modeled by camera plugin.
• Tilt-compensated compass — CMPS14, modeled by imu and magnetometer
  plugins.
• Altimeter — Infineon DPS310, modeled by air_pressure plugin.
• Wheel odometry - wheel encoders modelled by pose-publisher
  plugin.
• Gas sensor — Winsen MH-Z19B, modeled by GasEmitterDetector plugin.

Control

Freyja is controlled by the open-source Osgar framework or by custom Erro framework.

Motion Characteristics

Based on the tests specified in the DARPA SubT Challenge Model Preparation
Guide, this vehicle has the following motion
constraint characteristics:

• x velocity range from -2.5 m/s to 2.5 m/s
• x acceleration range from -10.6 m/s² to 10.6 m/s²
• Turning radius of 0.0 m

The constraints can be found in the following locations within the simulation model
package:

• Front left wheel maximum velocity and torque — model.sdf, lines 1415 and 1417
• Other wheels — just below Front Left wheel in the same file.

Endurance Characteristics

Based on the tests specified in the DARPA SubT Challenge Model Preparation
Guide, this vehicle has the following
endurance characteristics:

• Battery life of 14400 seconds

Diversions from Physical Hardware of Freyja

Virtual Freyja is a faithful representation of real-world Freya both in appereance and
in physical properties.

Freyja Validation and Specification Links

• https://www.uumotor.com/10-inch-single-shaft-brushless-motor-sensorless.html
• https://www.robot-electronics.co.uk/cmps14-tilt-compensated-compass.html
• Nearest public documentation to TIM881P: https://www.sick.com/ch/en/detection-and-ranging-solutions/2d-lidar-sensors/tim5xx/tim581-2050101/p/p619344
• https://www.kayetoncctv.com/global-shutter-high-speed-120fps-hd-720p-webcam-uvc-plug-play-driverless-usb-camera-module-for-android-linux-windows-mac/
• https://www.infineon.com/cms/en/product/sensor/pressure-sensors/absolute-pressure-sensors-map-bap/dps310/
• https://www.winsen-sensor.com/sensors/co2-sensor/mh-z19b.html
• https://youtu.be/cHJ-ZloPmhE (speed test)
• https://youtu.be/bZ83Zneuhf8 (rotation test)
• https://drive.google.com/drive/folders/1M8W3vjP1G0Pz7oeB7dAkBjXhYE05hvxA?usp=sharing

[m3d]

Any news?

[acschang]

The initial assessment of the Robotika Freyja model is complete, however there are some issues to resolve before this model can be merged and utilized in a competitive setting:

• The returns from the LIDAR do not appear to be accurate; please correct the orientation of the mounted LIDAR.
• Please verify the orientation of the left camera is as intended.
• The battery life of the model is much shorter than the specified time of 14400 seconds. Please resolve.
• The right and rear cameras share the same topic prefix and thus are spliced together; please separate out the right camera feed.
• The intrinsic parameters for the monocular cameras in the model.sdf are incorrect. Please recalculate the intrinsics values.

Please address the issues noted above and then submit a pull request to update your submission by 5 JUNE. The submissions are expected to be incorporated into the SubT Virtual Testbed pending a successful review.

[m3d]

Thanks for a thorough review!

• Battery life: Parameters adjusted. Could you, please, point us to documentation about what the battery parameters are and how to set them? We did not manage to find it.
• Lidar parameters: Fixed.
• Orientation of the left camera: Fixed.
• Overlapping right and rear camera topics: Fixed.
• Intrinsic parameters of monocular cameras: Updated.

[m3d]

#439

[acschang]

* Battery life: Parameters adjusted. Could you, please, point us to documentation about what the battery parameters are and how to set them? We did not manage to find it.

Please check here for the documentation. Based on the documentation, the parameter to be adjusted is power_load to achieve the advertised battery life.

[jisa]

Thanks, @acschang, for the pointer. Unfortunately, it does not go very deep in details. How did you, for example, figure out the 3min lifetime in #381 (comment)?

[acschang]

@jisa
The way I interpret the documentation is that one is to plug in the constants to your physical battery (or use the ones provided in standard SubT ground vehcles -- i.e. X1) and then adjust power_load to reach the appropriate endurance time.

Typically I check endurance triggering the battery drain state by issuing a velocity command and then monitor the debug output such as shown in your updated PR. I am not currently aware of a quicker way to test this. Given that the Freya vehicle currently has a battery life of 30 minutes instead of the intended 240 minutes, I would divide the power_load parameter by 8 to increase battery endurance to 240 minutes and then verify experimentally.

There is also the option to perform the calculations from the source file to figure out the endurance of your parameters without running the simulation.

[nkoenig]

I'm merging this PR into the cave_feature_release3 branch. This robot will be available when the feature release branch is merged into master.

[jisa]

@nkoenig Sorry, I do not understand your change of capacity from 20 Ah, which corresponds to the real robot, to 5 Ah, which I do not know where it comes from. Isn't it cutting the driving time to a quarter?

[angelacmaio]

Validation data was not included to support the specified battery life of 14400 seconds as required by the Model Preparation Guide. The battery life has been reduced to 60 minutes to match the other UGVs for now, but if the endurance test data is provided, we can adjust the model to match the robot's demonstrated battery life.