Hardware Abstraction Layer

The HAL provides an interface between the robot control system (consisting of control system, safety system, and sequencer) and the hardware of the robot. Any signal from a hardware input or output must pass through the HAL.

• Using HAL Objects
• Configuration File
  • Scale and Range of Analog Signals
  • Setting Multiple Scales and Ranges
  • Configuration File for ROS
• Feature Functions
• Hardware Libraries
  • Hardware Simulator
• Reading from Mouse and XBoxController

The inputs and outputs of the system are given by a specific hardware setup. This can vary widely among different systems. To account for many possible hardware settings we use a configuration file. This file describes the current hardware together with the necessary library to access them, see Configuration File. The configuration given in the file can be loaded as follows:

  HAL& hal = HAL::instance();
  hal.readConfigFromFile(std::string file);

Most probably you want to pass the configuration file name via parameters to main with:

  HAL& hal = HAL::instance();
  hal.readConfigFromFile(&argc, argv);

Now, you can pass the configuration file with

$ ./myApplication -c /path/to/config/NameOfConfigurationFile

Note: This HAL option has to be the first option if additional command line options are used.

This call causes the following actions:

• the configuration file will be parsed
• the necessary hardware libraries will be loaded
• for each channel an appropriate object is created with the id given in the configuration file
• these objects will be registered in the HAL manager

All input objects of the HAL have a common type base type InputInterface while the output objects have a common type OutputInterface. Digital inputs or outputs are of type Input<bool> or Output<bool> respectively. Analog inputs or outputs are of type ScalableInput<double> or ScalableOutput<double> respectively.
The following functions are available:

  OutputInterface* getOutput(std::string name, bool exclusive = true);
  Output<bool>* getLogicOutput(std::string name, bool exclusive = true);
  ScalableOutput<double>* getScalableOutput(std::string name, bool exclusive = true);
  InputInterface* getInput(std::string name, bool exclusive = true);
  Input<bool>* getLogicInput(std::string name, bool exclusive = true);
  ScalableInput<double>* getScalableInput(std::string name, bool exclusive = true);