Drivers

Supported drivers

  • amber-cpp-drivers is a project which contains drivers written in C/C++. Supported drivers are following:

    • Ninedof - reading information from sensor located on robot which provides information about motion from sensors accelerometer, gyroscope and compass
    • Roboclaw - controlling engines
    • Stargazer - provides ability to localize robot using camera and markers
    • Location - software computed location based on information from Roboclaw and Hokuyo
    • Maestro - servo-motors used in arm

  • amber-python-drivers is a project which contains drivers written in python. Supported drivers are following:

    • Hokuyo - reading information from scanner about environment
    • DriveSupport - used to control engines, additional data are used like scans and motion data
    • DriveToPoint - allow to drive the route by list of points
    • Roboclaw - used to control engines without any additional support

Mediator configuration

Each driver has device type and number assigned. That values are set in Amber configuration. Configuration sould be saved in file apps/amber/priv/settings.config.

Example configuration:

{supervised_driver,
  {driver,
    {driver_name}
  },
  {driver_type_number, driver_nummber},
  [
    {cdriver, "path/to/driver"},
    {config_file, "path/to/driver/configuration"},
    {log_config_file, "path/to/log/configuration"}
  ]
}.

Paths to configuration are not required. Required is path to executable file used to start the driver.

Driver features

Driver is:

  • an application which is running on robot
  • an app. which is communicating with device connect to robot
  • an app. which is communicating with mediator using pipes

Driver is responsible for:

  • setting device parameters
  • supporting simultaneous and parallel access to device
  • monitoring clients presence and activity
  • sending messages to clients which are registered as subscribers for specific type of messages
  • receiving messages, servicing that messages and replying if it is needed

How it work

Ostrzeżenie

Following guidelines are as a consequence of common part in messages sent between clients and drivers. Using DriverMsg is not required. Message format can be manully definded, but so far drivers and clients does not support it.

Driver should support following features:

  • handling received messages:

    • DATA - contains data which should be processed by driver
    • PING - echo request sent by mediator to check if driver is still alive, current not used, as a result driver should reply from PONG
    • SUBSCRIBE i UNSUBSCRIBE - used for client registration
    • CLIENT_DIED - used to inform driver about closed client, as a result client should be removed from subscribers list similar to UNSUBSCRIBE

Additionally it is recommended that driver should sent DRIVER_DIED to mediator when it is closing correctly.

Also driver should support:

  • initialize device
  • set device parameters
  • buffer data from device
  • synchronous access to device

Example

Example of driver can be DummyDriver. Drivers use common parts.