arena-robot

ARENA-robot

Robot integration runtime for the ARENA.

Installation

Requires Python3.8+ (it probably runs fine on 3.6 and 3.7, but you will need your own NumPy wheels)

From PyPi:

pip install arena-robot

Latest development:

pip install git+https://github.com/arenaxr/arena-robot#egg=arena-robot

Or for development, clone the repo and from inside the directory:

pip install -e .

Modules

arenarobot

Services may be one of the following types:

• sensor: Primarily takes in data from a hardware device and publishes the data to its own topic. These are usually sensors (ex. IMU, lidar, etc.).
• processor: Primarily takes in data from another MQTT topic (typically a sensor, controller, or another processor) and publishes transformed data to its own topic. These are usually more computationally-heavy tasks that have been decouples from the sensor service or they are transformations that take in data from multiple sensors, processors, or controllers (ex. VIO, SLAM, navigation, etc.).
• controller: Primarily takes in data on its own topic and publishes data on its own topic. Controllers usually interact with hardware devices that constantly take in and produce data (ex. a robot, drone, etc.)

Services that stream to MQTT may be started with the arena-robot-service command. See examples/service_sensor_vl53l5cx_lidar_1.json for a service file example. All services require the following arguments:

• service_type: Required. See below for service types.
• instance_name: Required. The name of this running service.
• subtopic: Required. The device subtopic to publish to. For sensors, this will always be prefixed with sensors/. For processors, this will always be prefixed with processors/.
• interval_ms For services that run repeatedly, this is the interval. Set to -1 by default, which will fire the service once. Set to 0 to fire as fast as possible. This option is ignored for async-based services.

A service can be run with the arenaxr.org instance of ARENA with:

MQTTH=mqtt.arenaxr.org DEVICE=mydevicename arena-robot-service my_service.json

A complete set of example services may be found in the examples directory.

sensor_beluga_serial

This is a Beluga UWB sensor connected via serial:

• dev_path: Required. Path to the serial dev file device. For example, a Beluga USB serial device commonly shows up on Linux as /dev/ttyACM[0-9]+. Hardware serial ports are often /dev/ttyS[0-9]+. For USB devices, it is best practice to use the full serial device symlink like /dev/serial/by-id/usb-SEGGER_J-Link_000760025484-if00 so that the connection order does not affect the device assignment. If multiple USB devices of the same type are connected, then the /dev/serial/by-path/.* syminks should be used to select the serial device by USB port.
• beluga_id: Required. ID to assign to Beluga.
• baudrate: Optional. Defaults to 115200.
• beluga_rate: Optional. Defaults to 10. Rate in ms that Beluga will query and respond.
• beluga_channel: Optional. Defaults to unset. See Beluga documentation.
• beluga_tx_power: Optional. Defaults to unset. See Beluga documentation.
• beluga_timeout: Optional. Defaults to unset. See Beluga documentation.
• beluga_twr_mode: Optional. Defaults to unset. See Beluga documentation.
• beluga_led_mode: Optional. Defaults to unset. See Beluga documentation.

sensor_licosa_serial

This is a LiCosa IMU and lidar sensor connected via serial:

• dev_path: Required. Path to the serial dev file device. For example, a LiCosa USB serial device commonly shows up on Linux as /dev/ttyACM[0-9]+. Hardware serial ports are often /dev/ttyS[0-9]+. For USB devices, it is best practice to use the full serial device symlink like /dev/serial/by-id/usb-Raspberry_Pi_Pico_E4616C840F602C27-if00 so that the connection order does not affect the device assignment. If multiple USB devices of the same type are connected, then the /dev/serial/by-path/.* syminks should be used to select the serial device by USB port.
• baudrate: Optional. Defaults to 230400.

sensor_t265

This is an Intel T265:

• timeout_ms: Optional. Defaults to 500. Timeout in milliseconds for waiting for pose frames from the sensor.
• enable_pose_jumping: Optional. Defaults to False. Enable position jumping. See librealsense docs.
• enable_relocalization: Optional. Defaults to False. Enable appearance based relocalization. See librealsense docs.
• enable_mapping: Optional. Defaults to False. Enable an internal map. See librealsense docs.
• enable_map_preservation: Optional. Defaults to False. Preserve map from the previous run.
• enable_dynamic_calibration: Optional. Defaults to True. Enable dynamic calibration.

NOTE: This requires an extras package: pip install arena-robot[realsense]

processor_t265

This is an Intel T265 transformation processor. This service runs initially to set up callback listeners, so the interval_ms should always be -1. The available options are:

• sensor_t265_topic: Required. Full path to the topic with the T265 data. Note that the processor will ignore sensor messages that are not from a sensor_t265 instance.
• sensor_t265_instance_name: Optional. Defaults to None. Name of the T265 instance to process messages from. This is useful if multiple T265 instances are publishing to a topic and you would like to ignore all but one of them.
• camera_orientation: Optional. Defaults to 0. The orientation options are:
  • 0: Forward, USB port to the right
  • 1: Downfacing, USB port to the right
  • 2: 45 degree forward
  • 3: Upward facing, USB port to the right
• scale_factor: Optional. Defaults to 1. Scale factor to apply to body transformations.
• jump_threshold_translation: Optional. Defaults to 0.1. Position jump detection threshold in meters. This value should be relative to how frequent is the position data is obtained (200Hz for the T265).
• jump_threshold_velocity: Optional. Defaults to 20. Velocity jump detection threshold in meters/second. This value should be relative to how frequent is the velocity data is obtained (200Hz for the T265).

sensor_vl53l5cx

This is a lidar sensor that connects through I2C and addresses by toggling its LPn pins. It additionally supports the following arguments:

• dev_path: Required. Path to the I2C dev file device. For example, the first I2C port on the Raspberry Pi is /dev/i2c-1.
• gpio_path: Required. Path to the GPIO dev file device. For example, the first I2C port on the Raspberry Pi is /dev/gpiochip0.
• rst_pin: Required. Pin (integer) on gpio_path connected to the I2C_RST pin on all of the sensors.
• lpn_pins: Required. Array of pins (integers) on gpio_path connected to Lpn pins on each sensor. The array must be present, and at least one pin must be specified or the service won't initialized any sensors. Sensors will be initialized and addressed in te order if this array.

processor_apriltag_detector

This processor reads frames, detects Apriltags, and returns camera pose given a known set of Apriltag locations. All services require the following arguments:

• video_file: Required. Where frames should be read from. e.g. /dev/video0 (v4l) or http://localhost:8265/cam1 (mjpeg)
• camera_resolution: Required. 2-element list. [horizontal resolution, vertical resolution]
• camera_params: Required. Camera parameters fx, fy, cx, cy
• dist_params: Required. Distortion parameters k1, k2, p1, p2, k3
• apriltag_locations: Required. Dictionary with Apriltag IDs as keys and 2D-list tag poses as values. The 2D-list should be a 4x4 matrix. The uppermost left 3x3 matrix should represent the rotation matrix of the Apriltag. The rightmost column, from top to bottom, contains the x, y, and z coordinates of the Apriltag's translation. The bottom row should be [0, 0, 0, 1] to allow for transformation-related matrix operations.

The following parameters are for the Python bindings for the Apriltags library:

• apriltag_family: Optional. Defaults to 'tag36h11'. See above documentation.
• tag_size: Optional. Defaults to 0.15. See above documentation.
• num_detector_threads: Optional. Defaults to 1. See above documentation.
• quad_decimate: Optional. Defaults to 2.0. See above documentation.
• quad_sigma: Optional. Defaults to 0.0. See above documentation.
• refine_edges: Optional. Defaults to 1. See above documentation.
• decode_sharpening: Optional. Defaults to 0.25. See above documentation.

NOTE: This requires an extras package: pip install arena-robot[apriltag_detector]

controller_pololu_slave_i2c

This controller allows for controlling and receiving data from a Pololu slave device over I2C. This service has been abstracted to work with any data configuration provided by the I2C driver on the Arduino side.

Flash the Pololu sketch to the A-Star or Romi. Examples for both boards may be found here, but you should not download these directly. So, prepare the hardware like so:

1. You will need to install either the AStar32U4 Arduino Library or the Romi32U4 Arduino Library insalled in the Arduino IDE.
2. Install the PololuRPiSlave Arduino Library and load the example for your board via the Arduino example menu.
3. Using raspi-config, enable I2C (if using a Raspberry Pi).
4. Add dtparam=i2c_arm_baudrate=400000 to /boot/config.txt (if using a Raspberry Pi).
5. Reboot

The example service configuration found at examples/service_controller_pololu_slave_i2c_romi.json matches the Data struct defined in the Romi example found here (note: this is a permalink to a specific Git version of this file).

interval_ms should be set to 100 ms by default, matching the Pololu polling speed. Anything faster is not guaranteed to work. All services require the following arguments:

• dev_path: Required. Path to the I2C dev file device. For example, the first I2C port on the Raspberry Pi is /dev/i2c-1.
• slave_data_types: Required. Dictionary of objects for each data type found in the Pololu Data struct in the order they are defined in the struct. Each top level key in this dictionary is the friendly name for the data type. Each object for these keys may contain:
  • format: Required. A single string character matching a Python Struct Format Character. Repeated characters can be accomplished with the num_items field. This also ensure that strings are handled properly.
  • num_items: Required. The number of items this data type has. Multiple items will be returned as a list in MQTT with this key. Must be at least 1.
  • write: Required. Bool of whether or not this field may be written to.
  • initial: Required if write is true. For more fields, this is an array of initial values. Number of items in list should match num_items. If format is s, then this should be a string with the number of characters of num_items (note that strings like \u0000 count as one character).

The controller receives commands on its own MQTT topic. It will only processor commands that are well-formed and targeted for the specific instance. Commands consist of a standard ARENA-robot message with a key called pololu_device_commands in data. Commands will be executed in the order listed. This key consists of an array of objects, each containing:

• name: Required. The name of the field to be set. This matches the key for each object in slave_data_types.
• value: Required. Either a list of items (for fields with num_items greater than 1) or a single value to set. For string fields, this must always be a string (not a list).
• index: Optional. An integer offset for setting values. This allows values in the middle at at the end of a field with num_items greater than 1 to be set without setting the earlier values.

For example, to turn on the red LED on an instance called service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi from the command line:

arenaxr_pub -t realm/d/myuser/mydevice/controllers/robot -m '"{\"target_device_instance_name\": \"service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi\", \"msg\": {\"data\": {\"pololu_device_commands\": [{\"name\": \"led_red\", \"value\": true}]}}}"'

{
  "target_device_instance_name": "service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi",
  "msg": {
    "data": {
      "pololu_device_commands": [
        {"name": "led_red", "value": true}
      ]
    }
  }
}

To play a tune:

arenaxr_pub -t realm/d/myuser/mydevice/controllers/robot -m '"{\"target_device_instance_name\": \"service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi\", \"msg\": {\"data\": {\"pololu_device_commands\": [{\"name\": \"notes\", \"value\": \"l16ceg>c\"}, {\"name\": \"notes_play\", \"value\": true}]}}}"'

{
  "target_device_instance_name": "service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi",
  "msg": {
    "data": {
      "pololu_device_commands": [
        {"name": "notes", "value": "l16ceg>c"},
        {"name": "notes_play", "value": true}
      ]
    }
  }
}

To set both motors (causing a spin):

arenaxr_pub -t realm/d/myuser/mydevice/controllers/robot -m '"{\"target_device_instance_name\": \"service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi\", \"msg\": {\"data\": {\"pololu_device_commands\": [{\"name\": \"motors\", \"value\": [-512, 512]}]}}}"'

{
  "target_device_instance_name": "service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi",
  "msg": {
    "data": {
      "pololu_device_commands": [
        {"name": "motors", "value": [-512, 512]}
      ]
    }
  }
}

To set only the second motor (makes use of the index field):

arenaxr_pub -t realm/d/myuser/mydevice/controllers/robot -m '"{\"target_device_instance_name\": \"service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi\", \"msg\": {\"data\": {\"pololu_device_commands\": [{\"name\": \"motors\", \"value\": [60], \"index\": 1}]}}}"'

{
  "target_device_instance_name": "service_controller_pololu_slave_i2c_pololu_slave_i2c_1_romi",
  "msg": {
    "data": {
      "pololu_device_commands": [
        {"name": "motors", "value": [60], "index": 1}
      ]
    }
  }
}

arenavideocall

After installing the repo, you should now have the arena-video-call-chrome command. You can also run it with python3 -m arena-video-call-chrome. It uses the standard arena-py scene environment variables.

The first argument sets the surface that the video should be mapped to. For example, to map to an object called avideobox:

MQTTH=mqtt.arenaxr.org NAMESPACE=namespace SCENE=scene arena-video-call-chrome avideobox

licosa_py

The licosa_py module depends only on NumPy. It includes a packet parser but not the serial interface; you will need to provide this yourself. See examples/licosa_py_basic.py for an example.

vl53l5cx_py

The vl53l5cx_py module requires Linux I2C interface (linux/i2c.h and linux/i2c-dev.h). It will issue a RuntimeError on other platforms if it is attempted to initialize.

C shared library

gcc -fPIC -shared -o vl53l5cx.so -Ivl53l5cx_py/include -Ivl53l5cx_py/VL53L5CX_Linux_driver_1.1.2/user/platform -Ivl53l5cx_py/VL53L5CX_Linux_driver_1.1.2/user/uld-driver/inc vl53l5cx_py/src/*.c vl53l5cx_py/VL53L5CX_Linux_driver_1.1.2/user/platform/*.c vl53l5cx_py/VL53L5CX_Linux_driver_1.1.2/user/uld-driver/src/*.c -l

License

Copyright (c) 2021, The CONIX Research Center All rights reserved.

This source code is licensed under the BSD-3-Clause license found in the LICENSE file in the root directory of this source tree.