Class ControllerInterfaceBase

Inheritance Relationships

Base Type

  • public rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface

Derived Types

Class Documentation

class ControllerInterfaceBase : public rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface

Base interface class for an controller. The interface may not be used to implement a controller. The class provides definitions for ControllerInterface and ChainableControllerInterface that should be implemented and extended for a specific controller.

Subclassed by controller_interface::ChainableControllerInterface, controller_interface::ControllerInterface

Public Functions

CONTROLLER_INTERFACE_PUBLIC ControllerInterfaceBase() = default
virtual CONTROLLER_INTERFACE_PUBLIC ~ControllerInterfaceBase() = default
virtual CONTROLLER_INTERFACE_PUBLIC InterfaceConfiguration command_interface_configuration () const =0

Get configuration for controller’s required command interfaces.

Method used by the controller_manager to get the set of command interfaces used by the controller. Each controller can use individual method to determine interface names that in simples case have the following format: <joint>/<interface>. The method is called only in inactive or active state, i.e., on_configure has to be called first. The configuration is used to check if controller can be activated and to claim interfaces from hardware. The claimed interfaces are populated in the command_interfaces_ member.

Returns:

configuration of command interfaces.

virtual CONTROLLER_INTERFACE_PUBLIC InterfaceConfiguration state_interface_configuration () const =0

Get configuration for controller’s required state interfaces.

Method used by the controller_manager to get the set of state interface used by the controller. Each controller can use individual method to determine interface names that in simples case have the following format: <joint>/<interface>. The method is called only in inactive or active state, i.e., on_configure has to be called first. The configuration is used to check if controller can be activated and to claim interfaces from hardware. The claimed interfaces are populated in the state_interface_ member.

Returns:

configuration of state interfaces.

virtual CONTROLLER_INTERFACE_PUBLIC void assign_interfaces (std::vector< hardware_interface::LoanedCommandInterface > &&command_interfaces, std::vector< hardware_interface::LoanedStateInterface > &&state_interfaces)

Method that assigns the Loaned interfaces to the controller.

Method used by the controller_manager to assign the interfaces to the controller.

Note

When this method is overridden, the user has to also implement the release_interfaces method by overriding it to release the interfaces.

Parameters:

  • command_interfaces – [in] vector of command interfaces to be assigned to the controller.

  • state_interfaces – [in] vector of state interfaces to be assigned to the controller.

virtual CONTROLLER_INTERFACE_PUBLIC void release_interfaces ()

Method that releases the Loaned interfaces from the controller.

Method used by the controller_manager to release the interfaces from the controller.

CONTROLLER_INTERFACE_PUBLIC return_type init (const std::string &controller_name, const std::string &urdf, unsigned int cm_update_rate, const std::string &node_namespace, const rclcpp::NodeOptions &node_options)
CONTROLLER_INTERFACE_PUBLIC const rclcpp_lifecycle::State & configure ()

Custom configure method to read additional parameters for controller-nodes.

virtual CONTROLLER_INTERFACE_PUBLIC CallbackReturn on_init ()=0

Extending interface with initialization method which is individual for each controller.

virtual CONTROLLER_INTERFACE_PUBLIC return_type update (const rclcpp::Time &time, const rclcpp::Duration &period)=0

Control step update. Command interfaces are updated based on on reference inputs and current states. The method called in the (real-time) control loop.

Parameters:

  • time – [in] The time at the start of this control loop iteration

  • period – [in] The measured time since the last control loop iteration

Returns:

return_type::OK if update is successfully, otherwise return_type::ERROR.

CONTROLLER_INTERFACE_PUBLIC std::pair< bool, return_type > trigger_update (const rclcpp::Time &time, const rclcpp::Duration &period)

Trigger update method. This method is used by the controller_manager to trigger the update method of the controller. The method is used to trigger the update method of the controller synchronously or asynchronously, based on the controller configuration. The method called in the (real-time) control loop.

Parameters:

  • time – [in] The time at the start of this control loop iteration

  • period – [in] The measured time taken by the last control loop iteration

Returns:

A pair with the first element being a boolean indicating if the async callback method was triggered and the second element being the last return value of the async function. For more details check the AsyncFunctionHandler implementation in realtime_tools package.

CONTROLLER_INTERFACE_PUBLIC std::shared_ptr< rclcpp_lifecycle::LifecycleNode > get_node ()
CONTROLLER_INTERFACE_PUBLIC std::shared_ptr< const rclcpp_lifecycle::LifecycleNode > get_node () const
CONTROLLER_INTERFACE_PUBLIC const rclcpp_lifecycle::State & get_lifecycle_state () const
CONTROLLER_INTERFACE_PUBLIC unsigned int get_update_rate () const
CONTROLLER_INTERFACE_PUBLIC bool is_async () const
CONTROLLER_INTERFACE_PUBLIC const std::string & get_robot_description () const
inline virtual CONTROLLER_INTERFACE_PUBLIC rclcpp::NodeOptions define_custom_node_options () const

Method used by the controller_manager for base NodeOptions to instantiate the Lifecycle node of the controller upon loading the controller.

Note

The controller_manager will modify these NodeOptions in case a params file is passed by the spawner to load the controller parameters or when controllers are loaded in simulation (see ros2_control#1311, ros2_controllers#698 , ros2_controllers#795,ros2_controllers#966 for more details)

Returns:

NodeOptions required for the configuration of the controller lifecycle node

template<typename ParameterT>
inline auto auto_declare(const std::string &name, const ParameterT &default_value)

Declare and initialize a parameter with a type.

Wrapper function for templated node’s declare_parameter() which checks if parameter is already declared. For use in all components that inherit from ControllerInterfaceBase

virtual CONTROLLER_INTERFACE_PUBLIC bool is_chainable () const =0

Get information if a controller is chainable.

Get information if a controller is chainable.

Returns:

true is controller is chainable and false if it is not.

virtual CONTROLLER_INTERFACE_PUBLIC std::vector< hardware_interface::CommandInterface::SharedPtr > export_reference_interfaces ()=0

Export interfaces for a chainable controller that can be used as command interface of other controllers.

Returns:

list of command interfaces for preceding controllers.

virtual CONTROLLER_INTERFACE_PUBLIC std::vector< hardware_interface::StateInterface::ConstSharedPtr > export_state_interfaces ()=0

Export interfaces for a chainable controller that can be used as state interface by other controllers.

Returns:

list of state interfaces for preceding controllers.

virtual CONTROLLER_INTERFACE_PUBLIC bool set_chained_mode (bool chained_mode)=0

Set chained mode of a chainable controller. This method triggers internal processes to switch a chainable controller to “chained” mode and vice-versa. Setting controller to “chained” mode usually involves the usage of the controller’s reference interfaces by the other controllers

Returns:

true if mode is switched successfully and false if not.

virtual CONTROLLER_INTERFACE_PUBLIC bool is_in_chained_mode () const =0

Get information if a controller is currently in chained mode.

Get information about controller if it is currently used in chained mode. In chained mode only internal interfaces are available and all subscribers are expected to be disabled. This prevents concurrent writing to controller’s inputs from multiple sources.

Returns:

true is controller is in chained mode and false if it is not.

CONTROLLER_INTERFACE_PUBLIC void wait_for_trigger_update_to_finish ()

Method to wait for any running async update cycle to finish after finishing the current cycle. This is needed to be called before deactivating the controller by the controller_manager, so that the interfaces still exist when the controller finishes its cycle and then it’s exits.

If the controller is running in async mode, the method will wait for the current async update to finish. If the controller is not running in async mode, the method will do nothing.

Note

The method is not real-time safe and shouldn’t be called in the control loop.

Protected Attributes

std::vector<hardware_interface::LoanedCommandInterface> command_interfaces_
std::vector<hardware_interface::LoanedStateInterface> state_interfaces_