Project Meeting 2004-11-15
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Project meeting
15 November 2004 (Mon), 7:30 pm, 101 Guggenheim
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Goals
- Get update on vehcile team and provide feedback for review
- Discuss tradeoffs of buying versus building actuation system
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Agenda
7:30 Goals, Agenda, Notetaker 7:35 Vehicle team presentation 8:05 Discussion: actuation system - build or buy 8:15 Upcoming events: Field Trip (H), Thanksgiving testing (Ike?) 8:30 Done
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Notes from meeting
- Vehicle team are waiting for the vehicle to arrive after the end of the month and this has meant that they are unable to start work on their various subsystems
- Vehicle team are considering to drop the transfer case actuation
- Kevin Cossel is to request information from all race teams on what on-board diagnostics (in addition to currently standard diagnostics) the teams require - this will then feed into the vehicle sub-team development of this area
- e-stop override system on the braking system should be included in the vehicle team brake actuator slide
- Need to make sure that embedded are fully represented when the vehicle team discuss actuation options as they will need to code the drivers/interfaces - this should be covered as Jeff L. & Tully are present at vehicle team actuation meetings
- Lars asked why we should not use the current steering actuation system created by us last year - Jeff apparently dislikes this option, although vehicle team uncertain of reasoning
- Elliot asked why pneumatic system should be used for the throttle control given that the system is not pressure sensitive (only position sensitive) - H asked why we need a physical (as opposed to electric) system to control the throttle given that the Sportsmobile throttle system is already fly-by-wire - Vehicle team replied that difficulty of electrically controlling the system is unknown and could be prohibitive, hence the interest in physical actuator control
- Elliot noted that there is a Caltech contact in Fords Diesel engine drive chain system group (via an Caltech CDS Alumni) and this contact can be exploited for actuation advice/assistance relating to the drive chain
- Lars asked about position sensing of the actuators (i.e. what is the current throttle position) - vehicle team replied that the EMC (commercial) system includes this information as standard in its output data
- Brakes & Ignition should be controlled by the e-stop system, when an e-stop disable signal is received the system should apply the brakes, stop and then turn off the ignition - note that this will mean that we lose power generation capability and hence we will need to run the electrical systems off batteries. This should not be an issue as DARPA will only use this option when they are taking us out of the race (i.e. NOT when they are planning to stop us overnight and then allow us to continue the next day - this would either be accounted for by the pause mode or some other darpa defined mode - Where did this come from? - Not detailed in the rules, vehicle team to follow up)
- Vehicle team need to lease with other teams to ensure that the power generation/supply (power draw) capabilities designed are actually sufficient for the other teams requirements
- Battery well will be in the rear of the vehicle (directly next to the rear doors) under the floor - which should be just behind the rear axle and hence should help to balance the weight of the engine at the front of the vehicle and their position (under the floor) should not significantly alter the CoG position
- Battery system will not be provided initially (when the vehicle arrives at the end of the term) - it will be a later addition
- Each Battery holds approx 2000J of energy - approximate battery life will last a couple of hours (although apparently a computer would eat through this is 15mins - vehicle team to check this...)
- Vehicle team need input from other teams about what information they require from the OBD-2 system (the built in on-board diagnostic system)
- Magnetometer on BOB produces very erratic outputs when the vehicle is in motion - although H states that it is only used for initial calibration/set-up of the communication system, and would prefer to keep the current system in the new vehicle as all of the code and interfaces are already written/prepared
- Gimbal sensor team will need to know accurately the state of the vehicle and this information will need to be provided from the IMU
- Vehicle team have said that obtaining and fitting a second IMU (backup) is not a high-priority
- Northrop Grumman have apparently stated that a second IMU is a possibility (they would donate) and they are currently building a PCI card interface to the IMU that will fit into one of our Dell servers (of which they currently have one)
- Lars says that the GPS position should NOT be close to the firewire cameras as this can cause interference - although the GPS position on the vehicle (or relative position to ground etc) is apparently unimportant - as long as the mount does not move independently of the vehicle (i.e. it must be mounted to a rigid position on the vehicle, not on flexible metal (i.e. the roof panel alone)
- Ike said that the embedded team is intended to buy a second GPS unit (of the same type to our current system)
- The sensor mount will not exist on ALICE when she is delivered at the end of the week as the terrain team have not heard back from the planning team as to what specifications are required for the sensors and hence the sensors are currently undecided and so terrain cannot dictate to the vehicle team what mounts are required
- Lars noted that the issue about sensor detail requirements needed by terrain from planning should be resolved ASAP - preferably by raising a bug in bugzilla, and there will be a meeting immediately after this one to resolve terrain's outstanding questions, terrain will then determine sensor requirements and then pass mounting requirements to the vehicle team.
- Vehicle team would like confirmation on the number of rack computers that will be used - available space will be 22U (2 * 11U stacks) if this is not sufficient they need to know ASAP
- Vehicle team need to add a specification to the external emergency stop buttons so that they are recessed into the body to ensure that they cannot be tripped unintentionally
- If Vehicle team us racing helmet radio systems then they need to ensure that there are sufficient sizes to cover all of the team (Elliot noted that these will hopefully be donated and hence several sizes will have to be requested at that time)
- Sportsmobile have suggested (informally through their use of language) that they will provide and install the monitors required in the vehicle to allow (human) team members to monitor/work on the system from within the vehicle - although the position of these monitors is still be considered by the vehicle team
- Actuator options - 1) $35,000 (actually more like $40,000 due to sales tax as EMC are in louisiana) for a complete DARPA special (?) system, apparently EMC have said that it is all or nothing (i.e. they will not provide a partial system) 2) Use a local supplier (competition to EMC) and use their turn-key / partial system 3) Run with a system designed and created by the team ourselves / in addition to using AI Motivators system currently being developed for BOB
- Cost of the DIY system is < $10,000
- EMC can provide a turn-key system in a week, hence ALICE would be actuated in time for the xmas field-test - whereas the DIY system would take significantly longer (exact time unknown), although Elliot expects that the DIY system could also be completed by the end of December
- Tully to create a forum where the issue of actuator options can be discussed
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