1. Final Design Review Winter Term 2005
Embedded Team
Coordinator: Ben Brantley
Henry Barnor
Ezra Berch
Thiago Costas
Tully Foote
Jeff Lamb
David Rosen
Alan Somers
Final Design Review Winter Term 2005
Darpa Grandchallenge
March,
Embedded Team

2. Embedded Team Scope
Provide a stable and uniform software and hardware platform for the other teams software to run on. (Computing and Hardware)
Provide computer interface to actuators and sensors. (Actuation + adrive+ SDS)
Establish a convenient, robust, and efficient inter-module messaging system. (SkyNet)
Provide a user interface appropriate for driving the vehicle. (SkynetGUI)
March,
Embedded Team

3. Specifications
Control of vehicle actuation capable of the following (defined from time command is issued by planning):
< 2 Seconds lock to lock steering
< ¼ Second to full brake
< ¼ Second to vehicle response to a throttle input
Computing hardware and management to survive 1 CPU failure and provide 7 computers initially, expandable to 12 computers. Including OS and non-race specific peripherals.
A intermodule and intercomputer messaging system capable of:
1ms Timestamping accuracy
1ms latency
>200mbs bandwidth
Reliable message passing available
March,
Embedded Team

4. Serial Device Server (SDS)
The SDS allows us to connect all serial devices to all computers via TCP/IP. This will allow the computer failure spec to be met. The SDS is a single point of failure, but without it, we cannot meet the redundancy spec.
March,
Embedded Team

5. Serial Device Server (SDS) Specifications
-Processor Type: ARM7 44MHz
-Memory: 8MB SDRAM/4MB flash
-32 serial ports
-1 Ethernet port
-SkyNet will talk to each port via TCP/IP
-RJ45 serial ports require physical adapters to DB9
-1U size (will be mounted in rack)
Specs:
-Physical connections robust enough to survive desert driving
-Abstraction layer allows clients to connect a serial device without the SDS, without having to re-write client code
-Round-trip time (total latency) through the SDS is 8 ms
-Can support simultaneous communication to all serial ports

6. Driving Software(adrive)
Current version fully operational w/
Steering, throttle, brake
Listening to commands over skynet
Returns position upon request over skynet.
Allows interface to simulator as well as hardware.

7. Race Computers Race Computers: 7 Dell Power Edge P4, 2.8Ghz
Running Gentoo Linux, Kernel >= 2.6.9
NFS mounted home directories for testing
NIS authentication for easy user management
Gigabit NICs connected to Gigabit switch
4 user, 8 computer KVM switch - easy development
March,
Embedded Team

8. Laptops 7 Laptops running Debian, Kernel 2.6
NFS mounted home directories when in shop
NIS authenticated when in shop
Single team account at field test
8th laptop acts as field server providing webserver, dns, subversion and dhcp
March,
Embedded Team

9. Field Wireless 2 wireless access points configured as a bridge.
Allows access to race computers from base camp in the field.
Allows access to race computers whiles vehicle is in motion.
Enables drive-by-wire of vehicle.
March,
Embedded Team

10. Operator Interface (skynetGUI)-Spiral 1
Graphical display of state and rddf
Graphical Display of fused sensor maps
Displays planned path and path history
Start and stops modules on race computers
Load balances the modules
Logs and displays last 500 Adrive commands
March,
Embedded Team

11. Module Starter
Starts modules on race computers based on skynet message
Config file provides ID, to uniquely identify each module starter
Kill modules based on skynet message
March,
Embedded Team

12. Current Resources Managed In Shop and Field Test
1 Print server installed in shop.
1 Distributed compilation machine – P4 3GHZ – reduce compile time and load on laptops. Compatible with race computer setup.
2-3 Development workstations in shop in addition to 8 laptops.
Laptops running Debian distribution.
NFS/NIS on all development machines with local team accounts for non-networked use.
Exploring NFS/NIS solutions for field tests.
3 wireless access points (Field base, shop, alice).
Field Server provides DNS, DHCP, subversion, Bugzilla and Wiki.
Exploring backup operations for multi-day field tests.
March,
Embedded Team

13. Actuation Part 1 Throttle Steering Brake
Atmel controller with three DACs interfacing with the Ford digital throttle.
Position Feedback provided by the throttle position sensor via OBDII (not yet implemented)
Steering
RoboteQ controller connected to a DC motor
Motor and gearbox on order.
Interim solution of legacy Parker Servo Motor
Brake
Atmel controller providing a 4 bit digital signal to pneumatic solenoid valves controlling 4 pneumatic cylinders.
Functional and calibrated.
Independent brake pressure transducer for feedback.
March,
Embedded Team

14. Actuation Part 2 Transmission E-Stop OBD-II
This will be the same as last year. A linear actuator cable pull, controlled over serial interface.
Not yet implemented.
E-Stop
Analog circuitry under development.
Radio system from airplane remote control.
Will have RS-232 interface.
OBD-II
Autotap OBD-II converter to serial interface.
CAN buss interface issues.
Investigating alternative CANalyzer by Vector Informatiks associated with Bosch
March,
Embedded Team

15. Skynet
Distributed message passing and control system. Used for intermodule communication.
REQUIREMENTS
Machine/IP independent module location (so that we don't have to lock a module onto a given machine)
Support for identifying machines capable of running a module and startup of that module on that machine (in case a machine goes down in the race)
Very low latency operation (<1 msec timestamping, ~1 msec latency). We are going to need this for timing synchronization
> 97% reliability for all messages, 100% reliability for select messages
Need the ability to uniquely identify modules that may have multiple instances running (such as multiple image processing modules)
Need ability to disconnect modules (so multiple people can run simulations at the same time on the same set of computers)
March,
Embedded Team

16. Architecture
March,
Embedded Team

17. API C, C++ Three messages paradigms:
Short, unreliable messages
Long, reliable messages
Distributed global variables
Very little structure forced upon the module
Rate limiting of modules handled automatically
March,
Embedded Team

18. Control and Operator Interface
Spun off into separate project, SkynetGui
Integrates sensing, planning, and state output visually
March,
Embedded Team

19. Status Messaging Control - Implemented over global variables layer.
Short, unreliable messages
Large messages
Reliable messages
Shared global variables – no demand yet
Module Registration
Control - Implemented over global variables layer.
Skynet Operator Interface
Synchronized module timing.
March,
Embedded Team

20. RFA responses COTS board Simulation environment
Not feasible due to resources and manpower.
Simulation environment
New modelling sub team CDS 190 is working on this.
Maintenance of development environment
New sub team build team
In charge of build dependancies and code structure.
Latency of Skynet Messages Quantified
1024 byte packets exchanging at a total bandwidth of 2MB/s on an otherwise unladen network, round-trip latencies averaged 459 us with standard deviation of 105 us and a maximum 743 us.
More comprehensive tests under development.
March,
Embedded Team

21. Timeline March 2005 Spring Break Field Test Spring Term 2005
Implement preliminary E-Stop Functionality
Continue testing and verification of SDS functionality.
Implement operational skynetGUI
Provide ability to remotely start and stop modules.
Provide the networking and computers necessary to support the field test.
Spring Term 2005
Replace Parker System with Roboteq Steering.
Implement transmission and ignition actuators.
Provide a functional message passing system between modules.
Maintain computing hardware necessary to run tests setup in Alice.
Maintain and improve skynet and skynetGUI.
March,
Embedded Team

22. Summary
Adrive implemented over skynet listening for commands and providing feedback.
Brake throttle and steering actuation implemented with SDS and calibrated.
SkyNet providing base functionality.
skynetGUI basic visualization functionality, other functions under development.
Module Starter under testing, expect operational by spring field test.
3 fully functional workstations providing access to all computing in Alice.
March,
Embedded Team