1. 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.

2. 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

3. Hybrid Controls Applications Fault Tolerant Control: Collective/RPM Controller Switch (Yavrucuk-Prasad2000)

4. Identifying Transition Management Patterns Hybrid Control System Applications StanfordOthers...GT Vanderbilt/ Budapest GT: Transition Management Patterns Support for transition strategies (discrete controller switch, signal blending, transient compensation, initialization) Open Control Platform (RT Corba-based distribution substrate)

5. Presentation Outline 4Motivation: Hybrid Control Systems Design Background: Open Control Platform (OCP) –Middleware for Distributed Hybrid Controls Applications Transition Management Pattern –Design and Uses –Examples Future

6. Layers of Open Control Platform Core OCP Real time distributed computing substrate with dynamic scheduling ReconfigurableControls API Components, signals,QoS, runtime changes Generic Hybrid Controls API Reuse of generic patterns for hybrid control, configuration transition management Fault Detection/ Identification UAV Flight Dynamics Model Mode Transitioning Vision System Mission Control Station RPM Controller GPS IMU (OCP is developed by Georgia Tech, Boeing/WashU, Honeywell, UCBerkeley under DARPA’s Software Enabled Control Program.)

7. Presentation Outline 4Motivation: Hybrid Control Systems Design 4Background: Open Control Platform (OCP) –Middleware for Distributed Hybrid Controls Applications Transition Management Pattern –Design and Uses –Examples Future

8. 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

9. 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

10. Components of the Transition Manager 111 * ** 11..*11 User CoordinatorUser Function 1 * Mechanism Implementation Coordinator Update() Rewiring/ Collation Mechanism Push() Blending Function BlendData() Component Generic Pattern Implementation

11. 111 * ** 11..*11 User CoordinatorUser Function 1 * Mechanism Implementation Coordinator Update() Rewiring/ Collation Mechanism Push() Blending Function BlendData() Component Simple TM Example: Sonar/GPS GPSSONAR BLEND GPS_Signal = Low / Activate Blending GPS_Signal = High / Activate GPS State Sonar_Signal = High / Activate Sonar State Sonar_Signal = Low / Activate Blending

12. Example Component Layout Transmitter 2 ConnectorReceiver BlenderData1 BlenderData2 BlenderData3 Transmitter 1

13. Layout of the Transition Manager Input Ports Output Ports Components Transition Coordinator Rewiring Mechanism Blender Function Rewiring Mechanism Blender Function C1 C2 C3 C4 C5 C6 Transition Manager Component

14. The Interaction of Blender Components CoordinatorMechanismFunction Start Blending() Receiving Inputs Push() Blend Data() Update() Sending Outputs End Blending() Activation Phase Operation Phase Deactivation Phase

15. Distributed Transition Management Input Ports Output Port Component 2 Rewiring Mechanism Blending Function Transition Coordinator Coordinator Proxy Component 1 Transition Coordinator Proxy Ports Discrete State Data

16. Presentation Outline 4Motivation: Hybrid Control Systems Design 4Background: Open Control Platform (OCP) –Middleware for Distributed Hybrid Controls Applications 4Transition Management Pattern –Design and Uses –Examples Future

17. 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 StanfordOthers...GT Vanderbilt/ Budapest GT: Standard reconfiguration/ transition strategies

18. Future of Hybrid Systems Modeling Front-End Integration

19. Future of Hybrid Systems Modeling (2)

20. Future of Hybrid Systems Modeling (3)

21. Transition Strategies Discrete controller switching –Simple switch from one controller to another (previously inactive) –Switch between concurrently running controllers Examples: GT Collective-RPM switch, Stanford VSTOL Blending –Blending of two (or more) components’ outputs Examples: Sonar/GPS, Gain scheduling, GT mode transitioning Transient compensation –Additional compensator to reduce transient induced by switching Example: Vanderbilt Initialization –State Zeroing –State Preserving (preserves previous controller’s state vector) –Output Fitting (matches controller outputs and, potentially, derivatives) –Just-in-time warm-up for dynamic compensators Example: Vanderbilt / Tech. Univ. of Budapest 2-link Planar Arm

22. Open Control Platform Goals Core OCP Distributed Object Computing Controls API Mission Control Station UAV Fault Detection/ Identification GPS IMU Vision System Flight Dynamics Model Mode Transitioning RPM Controller Integrate distributed components using controls domain abstractions Support dynamic reconfiguration (not just design-time development); plug-and-play extensibility, component interchangeability Enable reuse of generic domain-specific integration and reconfiguration patterns (beyond component-level reuse)