1. HRTC Meeting 12 September 2002, Vienna Smart Sensors Thomas Losert

2. 12 Sept. 2002 / p.1 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

3. 12 Sept. 2002 / p.2 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

4. 12 Sept. 2002 / p.3 Thomas Losert Smart Transducer (ST) Comprises the Integration of one or more Sensor/Actuator Elements with a Micro- controller and a Communication Network Interface that provides the following Services across standard Interfaces:  Diagnostic and Management  Real-Time Communication  Calibration of Sensor  Signal Conditioning and Conversion to standard Units

5. 12 Sept. 2002 / p.4 Thomas Losert Advantages  No noise pickup from long external signal transmission lines.  Better Diagnostics – Simple external ST failure modes (e.g., fail-silent)  "Plug-and-play" capability if the ST contains its own documentation on silicon or in an external database.  Reduction of the complexity at the system hardware and software and the internal ST failure modes can be hidden from the user by a well-designed fully specified ST interface.  Cost reduction in installation and maintenance.

6. 12 Sept. 2002 / p.5 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

7. 12 Sept. 2002 / p.6 Thomas Losert Observations An observation consists of an atomic tuple For Communication of Observations across an RS interface a common set of concepts is necessary:  Common representation of values in a Shared code-space  Common notion of time and its representation  Common meaning of the names of RT entities  Access protocol to the information.

8. 12 Sept. 2002 / p.7 Thomas Losert Observations An observation consists of an atomic tuple For Communication of Observations across an RS interface a common set of concepts is necessary:  Common representation of values in a Shared code-space  Common notion of time and its representation  Common meaning of the names of RT entities  Access protocol to the information.

9. 12 Sept. 2002 / p.8 Thomas Losert State vs. Event Values

10. 12 Sept. 2002 / p.9 Thomas Losert Observations An observation consists of an atomic tuple For Communication of Observations across an RS interface a common set of concepts is necessary:  Common representation of values in a Shared code-space  Common notion of time and its representation  Common meaning of the names of RT entities  Access protocol to the information.

11. 12 Sept. 2002 / p.10 Thomas Losert GPS - Time GPS weeks and GPS seconds since the GPS epoch (6. Jan. 1980, 00:00:00 UTC) Advantages: Continuous representation of Time (no leapseconds) High availability with low jitter Disadvantages: Overflow every 19.6 years because GPS week is represented as a 10 bit value

12. 12 Sept. 2002 / p.11 Thomas Losert Based on GPS; advantages of GPS are preserved Additional advantages: Enhanced granularity (about 60 ns) Easy Access to the full second No overflow during the lifetime of the product (horizon of more than 10 000 years) Easy manipulation of timestamps Global Notion of Time 2 -24 seconds external time format (8 bytes) 1 sec (2 0 seconds)2 39 seconds

13. 12 Sept. 2002 / p.12 Thomas Losert Observations An observation consists of an atomic tuple For Communication of Observations across an RS interface a common set of concepts is necessary:  Common representation of values in a Shared code-space  Common notion of time and its representation  Common meaning of the names of RT entities  Access protocol to the information.

14. 12 Sept. 2002 / p.13 Thomas Losert Interface File System (IFS) Hierarchical, distributed File-System that is the Source and Sink of each communication Map all relevant properties of a node into the IFS: Sensor and actuator data Calibration data, parameters, etc. Configuration Information Node identification (physical name, global name) Documentation and pointer to register service

15. 12 Sept. 2002 / p.14 Thomas Losert Global Name Is the concatenation of Cluster Name, Logical Name File Name, and Record Name Up to 250 Clusters Up to 250 Nodes Up to 64 Files Up to 256 Records

16. 12 Sept. 2002 / p.15 Thomas Losert Observations An observation consists of an atomic tuple For Communication of Observations across an RS interface a common set of concepts is necessary:  Common representation of values in a Shared code-space  Common notion of time and its representation  Common meaning of the names of RT entities  Access protocol to the information (see TTP/A).

17. 12 Sept. 2002 / p.16 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

18. 12 Sept. 2002 / p.17 Thomas Losert Three Interfaces of a Node

19. 12 Sept. 2002 / p.18 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

20. 12 Sept. 2002 / p.19 Thomas Losert Why Time-Triggered? Requirement to record value and instant when measurement was performed Requirement to perform synchronous distributed measurements Requirement to gather multiple measurements with bounded delay

21. 12 Sept. 2002 / p.20 Thomas Losert Principles of Operation: Temporal Firewall Best way of communication for Producer Best way of communication for Consumer Predictable time-triggered communication Components have access to a global time Communication and measurement synchronized Temporal firewall in communication

22. 12 Sept. 2002 / p.21 Thomas Losert Time-Triggered Protocol/Class A (TTP/A) Low-cost time-triggered sensor bus Supports „Smart Transducers“ Currently subject of a standardization process at Object Management Group

23. 12 Sept. 2002 / p.22 Thomas Losert Principles of Operation: TTP/A (1) One active master Up to 250 slaves Communication organized in rounds TDMA bus allocation

24. 12 Sept. 2002 / p.23 Thomas Losert Principles of Operation: TTP/A (2) Time-Triggered Protocol for Fieldbus Applications TDMA Bus Access Scheme Communication Organized into Rounds Supports Various Physical Layers Each round is initiated by the master by sending the Fireworks-Byte Multipartner (MP): Real-Time Service Interface Master/Slave (MS): Monitoring and Configuration

25. 12 Sept. 2002 / p.24 Thomas Losert TTP/A: Principles of Operation (2)

26. 12 Sept. 2002 / p.25 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

27. 12 Sept. 2002 / p.26 Thomas Losert Architecture

28. 12 Sept. 2002 / p.27 Thomas Losert CORBA CORBA Smart Transducers Interface (STI) Allows (re)configuration of the Smart Transducer cluster, e.g. over the internet Allows monitoring of the ST cluster Allows access to the real-time service interface for cases, when a RT-CORBA supporting end-to-end predictability is used

29. 12 Sept. 2002 / p.28 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

30. 12 Sept. 2002 / p.29 Thomas Losert „Sensor Fusion is the combination of sensory data or data derived from sensory data such that the resulting information is in some sense better than would be possible when these sources were used individually.“ Definition of Sensor Fusion

31. 12 Sept. 2002 / p.30 Thomas Losert „better“ can mean: More robust (fault-tolerant sensor clusters) Extended spatial and temporal coverage Increased confidence Reduced ambiguity and uncertainty Robustness against interference Improved resolution Emerging services Purposes of Sensor Fusion

32. 12 Sept. 2002 / p.31 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

33. 12 Sept. 2002 / p.32 Thomas Losert A Typical Sensor Fusion Control Loop

34. 12 Sept. 2002 / p.33 Thomas Losert Introducing a Sensor Fusion Model Three levels of computation: Node level Cluster level Control application level Well-defined interfaces between levels Smart Transducer Interface Environmental image

35. 12 Sept. 2002 / p.34 Thomas Losert Control Loop in the Three-Level Model

36. 12 Sept. 2002 / p.35 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

37. 12 Sept. 2002 / p.36 Thomas Losert Case Study: Autonomous Mobile Robot TTP/A fieldbus network with 1 master 1 node for sensor fusion and navigation 15 smart transducers (9 actuators/6 sensors)

38. 12 Sept. 2002 / p.37 Thomas Losert ST-Types 2 Ultrasonic Far Distance Sensors 3 Infrared Low Distance Sensors 1 Luminance Sensor 1 Steering Control 1 Speed Control 3 Servos for Moving Infrared Sensors 4 Lighting Control

39. 12 Sept. 2002 / p.38 Thomas Losert Control Loop

40. 12 Sept. 2002 / p.39 Thomas Losert The „Smart Car“

41. 12 Sept. 2002 / p.40 Thomas Losert Overview Smart Transducers (Definition, Observations, Interfaces) Principles of Operation Architecture Sensor Fusion (Definition, Concepts) Case Study Conclusion & Outlook

42. 12 Sept. 2002 / p.41 Thomas Losert Conclusion & Outlook Case Study Proof of concept for TTP/A Testbed for Sensor Fusion Demonstrator for CORBA-STI The Standard Proposal has been adopted in Jan. 2002 by the Board of Directors and is called Smart Transducers Interface Standard now. The standardization process continues...

43. 12 Sept. 2002 / p.42 Thomas Losert Thank you for your attention!