Real-Time Java AOCS Framework v1.0 API Specification

Package RtjAocsFramework.ControllerManagement

This package defines the covering the management of closed-loop controllers.

See:
          Description

Interface Summary
ControllerModeManager In most cases, the control algorithm to be applied to control a given variable will be different for different operational conditions.
 

Class Summary
Controller The Controller class is the class encapsulating a SISO controller.
ControllerManager This class encapsulates a controller manager.
CyclingControllerModeManager Encapsulation of a cycling mode manager for the controller mode manager.
FollowerControllerModeManager Encapsulation of a follower mode manager for the controller mode manager.
TestCaseController_0 Test case for the ControllerManagement framelet.
TestCaseController_1 Test case for the ControllerManagement framelet.
TestCaseController_2 Test case for the ControllerManagement framelet.
TestCaseController_3 Test case for the ControllerManagement framelet.
TestCaseController_4 Test case for the ControllerManagement framelet.
TestCaseController_5 Test case for the ControllerManagement framelet.
 

Package RtjAocsFramework.ControllerManagement Description

This package defines the covering the management of closed-loop controllers. Closed-loop controllers are widely used inside AOCS applications. They are primarily used to control the satellite attitude but can also be used to control the satellite orbit or the reaction wheel speeds. The framework assumes the controller to conform to the following model:
 
 
The figure shows a classical closed loop control system. The arrows represent signal flows and each arrow can represent several parallel flows. The boxes represent multi-input-multi-output transfer functions.

The inputs to a controller are:
· The reference signals that must be tracked by the controller
· The measurements from a sensor
· The feedforward compensation signals that are added to the control output and typically model known disturbances
The sensor measurement inputs are mandatory. The reference signals and feedforward compensation inputs are optional. If they are absent, the controller assumes that they are equal to zero.

A controller has three outputs:
· The actuator commands that represent the commands for the actuator
· The compensator outputs that represent the inputs to the compensator block
· The control errors that are obtained as the difference between filtered measurements and reference signals
The actuator command outputs are mandatory. The other two outputs are optional.

A controller includes four transfer function blocks:
· The compensator which implements the control law
· The measurement filter that filters the measurement signals
· The feedforward filter that filters the feedforward signals
· The reference signal filter that filters the reference signals
Explicit specification of the compensator transfer function is mandatory. The other transfer function blocks need not be specified by the user in which case they are implicitly assumed to be equal to 1. The measurement filter block often represents an estimator. The transfer function blocks are implemented in the AOCS framework using the control channel concept.

The framework encapsulates closed-loop controllers of the kind presented in the figure in dedicated components called controller objects. Controller objects are implemented as instances of class Controller.

The management of the controllers is done in accordance with the Controller Management Design Pattern. Controller management is described in the Controller Management Framalet document.


Real-Time Java AOCS Framework v1.0 API Specification

Real-Time Java AOCS Framework project home page

Automatic Control Laboratory, ETH Zuerich
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