Rotary Racer Car Data

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Rotary Racer - Car Performance

Castle Coombe 2011-10-02

Results

An excellent race. The weather was brilliant, sunny and warm with a reasonably light wind (16 km/h ?). The car was RR8h. A tail peice befind the rear brake light had been added.

Car Computer Log

This shows the main items measured by the Rotary Racers car computer. They are:

Item Description
Throttle The position of the twist grip throttle from 0 to 100%
MotorCtl The motor power output setting. The Car computer sets the motor power based on the drivers throttle position, the speed of the car and the current being used. There is a software algorithm to implement this "drive by wire" system. The Car computer drives the PWM (Pulse Width Modulation) Motor Speed controller with a duty cycle proportional to this value. 0 - 100%
Speed The speed of the car in Km/H calculated from the magnetic read switch pulse generator by the Car Computer.
Voltage The batteries voltage under load.
Current The current being taken from the batteries.
Charge0 The charge left in the battery pack 0. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery.
Charge1 The charge left in the battery pack 1. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery.
Charge2 The charge left in the battery pack 2. This is calculated by the car computer using an algorithm that has been honed to match the battery discharge curves for the Yuasa batteries. It currently bases its results on the current being used from the battery.
BatPack The battery pack in use (0, 1 or 2), the turbo button (4) and the Pitstop warning (8) . We generally change the battery pack with each driver change.
Temp The Temperature of the motors casing in degrees C.
GPS GPS position, speed and time together with lap position information
Misc Other items describing the operation of the control system


The graphs show the overall data, the actual ASCII data log files are also available, from the links below, for detailed analysis.

Car Data Log

Practice Laps Data

Car Data

Notes

  • The Car was RR8h. This was the cars fifteenth race.
  • We used a 18:49 gear ratio.
  • The Castle Combe circuit is 2.977Km long and has a slight hill with sweeping corners. There was a slight wind on the day (16Km/H ?).
  • The software was car25. The Car electronics worked perfectly. Changes for this race were: Changed GpsCurrent average to be taked an GPS position 1. This allowed us to obtain the average current for the last lap just as the car comes into sight/range leaving more time for the operator to decide and change the power levels. Added battery number switch to car. This worked well and the battery changers remembered to change it !
  • The battery charge calculations worked well and the Voltage based charge measurement was about spot on.
  • The Car Computers "Average Current" setting was 16.00 Amps, the Control Speed was about 44 Km/Hour, this was tweaked during the race based on actual average lap current keeping it to around 17.5Amps.
  • Drivers were: Dan Dando, Gareth Barnaby, Ben Millar, Stepanie Dando, Louise Barnaby and Dawn Barnaby. The drivers drove excellently, went fast and kept out of trouble (apart from Dawns almost skirt onto the grass!) and keeping well clear of other cars by going around the outside (as far as we could see).
  • The motors temperature kept below 45 degrees, 10 degrees higher than Merrifield but it was a warmer day.
  • The battery packs were fine although we did take the first battery pack (0 RR7,RR8) a bit too low and the voltage levels went down alarmingly. The other battery packs were not used so heavily. We had about 15% left in the last set at the end of the race.
  • An excellent race an a superb 1st place result with 113miles.