A Pattern for Gradual Transitioning during Dynamic Component Replacement in

Extreme Performance UAV Hybrid Control Systems

Murat Guler, Linda Wills,

Scott Clements, Bonnie Heck,

George Vachtsevanos

School of Electrical and Computer Engineering

Georgia Institute of Technology

This research has been supported by DARPA’s Software Enabled Control Program.

Presentation Outline

• Motivation: Hybrid Control Systems Design

• Background: Open Control Platform (OCP)

– Middleware for Distributed Hybrid Controls Applications

• Transition Management Pattern

– Design and Uses

– Examples

• Future

Hybrid Controls Applications

GPS/Sonar TransitionGPS DataGPS Data GPS and SonarGPS and Sonar

Data BlendedData Blended Sonar DataSonar Data

Nonlinear Control of VSTOLAircraft (Oishi&Tomlin2000)

Fault Tolerant Control:Collective/RPM Controller Switch(Yavrucuk-Prasad2000)

Controller 1 Controller 2

Controller 3

Gain Scheduling

Blend 1-3 Blend 2-3

Blend 1-2

Identifying Transition Management Patterns

Hybrid Control System Applications

Stanford Others...GTVanderbilt/Budapest

GT: Transition Management PatternsSupport for transition strategies

(discrete controller switch, signal blending, transient compensation, initialization)

Open Control Platform(RT Corba-based distribution substrate)

Presentation Outline

Motivation: Hybrid Control Systems Design

• Background: Open Control Platform (OCP)

– Middleware for Distributed Hybrid Controls Applications

• Transition Management Pattern

– Design and Uses

– Examples

• Future

Layers of Open Control Platform

Core OCPReal time distributed computing

substrate with dynamic scheduling

Reconfigurable Controls APIComponents, signals, QoS, runtime changes

Generic Hybrid Controls APIReuse of generic patterns for hybrid control,

configuration transition management

Fault Detection/Identification

UAV

Flight Dynamics Model

Mode TransitioningVision SystemMission Control Station

RPM Controller

GPS

IMU

(OCP is developed by Georgia Tech, Boeing/WashU, Honeywell, UCBerkeley under DARPA’s Software Enabled Control Program.)

Presentation Outline

Motivation: Hybrid Control Systems Design

Background: Open Control Platform (OCP)

– Middleware for Distributed Hybrid Controls Applications

• Transition Management Pattern

– Design and Uses

– Examples

• Future

Transition Management Goals

• Ease of use by Controls Engineers.

• Modularity and robustness.

• Adaptability

• No Interruption in Processing

– Preserve Stability and Avoid Transients

• Separation of Discrete and Continuous Control Logic in

Hybrid Controls Systems

– Transition Coordinator : High level discrete decision

– Rewiring Mechanism : Rewiring/Collation of inputs and outputs

– Blending Function : Low level continuous system controllers

• Accommodation of distributed systems

Transition Management Pattern

• Intent– Graceful Transition in Reconfigurable Systems

• Applicability– Online Reconfiguration of Components

– Dynamic Transition of Hybrid Control Systems

– Data Fusion

• Example Uses– GPS/Sonar Sensor Data Fusion

– Mode Transitioning on a UAV

– Fault Tolerant UAV Model

Components of the Transition Manager

1 1 1* * *

1 1..* 1 1

User Coordinator User Function1

*

MechanismImplementation

Coordinator

Update()

Rewiring/CollationMechanism

Push()

BlendingFunction

BlendData()

Component

GenericPattern

Implementation

GPSGPS GPS and SonarGPS and SonarData BlendedData Blended SonarSonar

1 1 1* * *

1 1..* 1 1

User Coordinator User Function1

*

MechanismImplementation

Coordinator

Update()

Rewiring/CollationMechanism

Push()

BlendingFunction

BlendData()

Component

Channel 1

Blending

Channel 2

Channel 1

Channel 2

Output

Output_Signal = (GPS_Weight * GPS_Signal) + (Sonar_Weight * Sonar_Signal)

Simple TM Example: Sonar/GPS

GPS SONAR

BLENDGPS_Signal = Low /Activate Blending

GPS_Signal = High /Activate GPS State

Sonar_Signal = High /Activate Sonar State

Sonar_Signal = Low /Activate Blending

Example Component Layout

Transmitter 2

Connector Receiver

BlenderData1

BlenderData2

BlenderData3

Transmitter 1

Layout of the Transition Manager

Input Ports

Output Ports

Components

Transition Coordinator

RewiringMechanism

Blender Function

RewiringMechanism

Blender Function

C1

C2

C3

C4

C5

C6

Transition Manager Component

The Interaction of Blender Components

Coordinator Mechanism FunctionStart Blending()

Receiving Inputs

Push()

Blend Data()

Update()

Sending Outputs

End Blending()

ActivationPhase

OperationPhase

DeactivationPhase

Distributed Transition Management

Input Ports

Output Port

Component 2

RewiringMechanism

Blending Function

TransitionCoordinator

Coordinator Proxy

Coordinator Proxy

Component 1

TransitionCoordinator

Coordinator Proxy Ports

Discrete State Data

Presentation Outline

Motivation: Hybrid Control Systems Design

Background: Open Control Platform (OCP)

– Middleware for Distributed Hybrid Controls Applications

Transition Management Pattern

– Design and Uses

– Examples

• Future

Future Work

OCP (Boeing, GT, Honeywell, UCB)

GT: Transition Management Patterns (discrete controller switch, signal blending, transient compensation, initialization)

Specification & Modeling (GT & UCBerkeley)

Hybrid Control System Applications

Stanford Others...GTVanderbilt/Budapest

GT: Standard reconfiguration/

transition strategies