Quote:
Originally Posted by dmcguire3006
Good thing about CAN is that you can monitor motor voltage and current and hence computing a running energy expenditure tally would be quite simple.
Energy = Power*Time = Voltage*Current*Time
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D,
Dave has covered the single point failure response so I won't add to that. Computing energy usage as you suggest may be a little more difficult than you expect. Current spikes and voltage dips occur in short pulses that require frequent monitoring in order to be accurate. To spend a great deal of time gathering data and totaling the same may actually reduce your effectiveness in driving and accomplishing game goals. Should your samples occur at the rising or falling edge of a pulse and you were to calculate energy remaining on such data, you can imagine the result. Dependent on the load, motors draw full stall current each time they start. That current may be sustained over several brush commutations dependent on the motor in use or it may be present for a significant length of time. At any rate, there are other variables that come into play which would interfere with your calculations that are not monitored by the can bus. The most significant in my mind is battery temperature and it's effect on internal battery resistance and output current capability.