Controller Base

Overview

The controller base implements the basic ROS interfaces for the controller. This includes setting up subscribers, publishers and initializing parameter management. The idea of the base class, is that all interfacing with ROS and shared resources across all inheritance levels happens or are contained in this class.

ROS interfaces

The controller base has the following ROS interactions.

Figure 1: Controller's ROS interactions.

The controller has four ROS interfaces that are tracked as member variables of the class. These interfaces are the only points of contact that influence the every layer of the controller along side the node parameters. Each of the callbacks for the subscribers are also contained in controller_base.

ROS Interface	Topic	Explanation	Message Type
actuators_pub_	/command	Publishes the acutator commands for the aircraft. The publishing rate is controller by the timer_ object.	Command.msg
internals_pub_	/controller_inners_debug	Publishes the intermediate values created by the outer control loops. Published simultaneously as the commands when there is at least one subscriber to the topic.	ControllerInnersDebug.msg
controller_commands_sub_	/controller_commands	Subscribes to the commands for the controller.	ControllerCommands.msg
vehicle_state_sub_	/estimated_state	Subscribes to the estimated state of the aircraft.	State.msg

Note

The command message is from the rosflight_msgs package not the rosplane_msgs package.

Parameter Management

See the Parameter Management page for more details on how parameter management works.

List of Parameters

Parameter	Explanation	Range
pwm_rad_e	Radian to PWM conversion for the elevator.	$\geq 1.0$ (double)
pwm_rad_a	Radian to PWM conversion for the ailerons.	$\geq 1.0$ (double)
pwm_rad_r	Radian to PWM conversion for the rudder.	$\geq 1.0$ (double)
frequency	Frequency of the timer, effective control loop closure frequency.	$\geq 100$ (hertz, int)

Modifying Controller Base

The controller_base class should only contain things that are necessary for each layer of the controller. If you are considering adding something to the controller, but it only applies to one layer, perhaps reconsider. All ROS related items should also be stored here. For example, if you needed to use another topic subscription, the new subscriber should be created and stored in controller_base.

As shown in the Controller Software Architecture page, you may need to modify the main function in controller_base.cpp to use a newly implemented controller.