Honda Power Unit Hardware & Software

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
henry
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Re: Honda Power Unit Hardware & Software

Post by henry » Wed May 22, 2019 7:58 am

Tommy Cookers wrote:
Tue May 21, 2019 8:24 pm
j.yank wrote:
Tue May 21, 2019 4:51 pm
Tommy Cookers wrote:
Tue May 21, 2019 3:38 pm
accelerating whilst K-driving would give a weak TC-like effect but accelerating while K-generating would give anti-TC
and braking while K-generating would give a weak ABS-like effect
Can you elaborate more on why there would be anti-TC while K-generating? If the pedal is fully pressed out of the corner K-generating will act as a contra-torque supposedly preventing overspinning. Or maybe I have overlooked the thechnical regulations where this is not allowed?
maybe I was wrong
imo
there will be inner control (feedback) loops between the K and its controller
this must include what's effectively rpm feedback - ie the K is primarily velocity-controlled
an excessive rate of change of rpm ('slew limit') will cause the K to go from full + torque to full - torque (or vice-versa)
in a few millisec
eg wheelspin is one possible cause of this triggering of limit slew rate
accelerating with K assisting ICE - on wheelspin the K would go from +120 kW to -120 kW in in a few millisec (TC emulation)
accelerating with ICE driving K generation - on wheelspin the K would remain at -120 kW (no TC effect)

these are what could be regarded as control-implemented torque 'collapses'
there can in the absence of such control be other torque collapses related to MG design factors
I think what might be effected is wheelspin minimisation rather than traction control. The objective would be to reduce wear rather than to maximise traction.

I did a quick calculation and the slew rates in the low speed, traction limited, region are high. Perhaps 3,000rpm/s for the ICE and 10,000 for the MGU-K. So for the few milliseconds you mention that’s tens of revs. change.

Do you think they might monitor slew rate change in the MGU-K control trying to manage “jerk” which would be the onset of wheelspin?
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus

Brake Horse Power
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Re: Honda Power Unit Hardware & Software

Post by Brake Horse Power » Wed May 22, 2019 8:46 am

Is it really that fast to regulate on almost millisecond level? Do you even have a measuring accuracy so high that this makes sense?

-measuring
-signal to computer
-computing
-signal to motorcontroller
-adjusting power output to motor
All in few ms? Just asking.. I am no expert.

Bandit1216
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Re: Honda Power Unit Hardware & Software

Post by Bandit1216 » Wed May 22, 2019 2:21 pm

Brake Horse Power wrote:
Wed May 22, 2019 8:46 am
Is it really that fast to regulate on almost millisecond level? Do you even have a measuring accuracy so high that this makes sense?

-measuring
-signal to computer
-computing
-signal to motorcontroller
-adjusting power output to motor
All in few ms? Just asking.. I am no expert.
I don't think speed is the problem. The photon's travel 299 792,458 meter in one ms, right?

subcritical71
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Re: Honda Power Unit Hardware & Software

Post by subcritical71 » Wed May 22, 2019 3:09 pm

Brake Horse Power wrote:
Wed May 22, 2019 8:46 am
Is it really that fast to regulate on almost millisecond level? Do you even have a measuring accuracy so high that this makes sense?

-measuring
-signal to computer
-computing
-signal to motorcontroller
-adjusting power output to motor
All in few ms? Just asking.. I am no expert.
I don't think millisecond level is a problem at all with modern electronics. For the TAG-320 ECU, data acquisition is in the 10K parameters per second range and the ECU can handle 4000 MIPS (millions of instructions per second) or 4 Billion instructions per second. I must admit though that only having 50ms between driver input and PU torque delivery as measured by the crankshaft sensor seems a bit fast to me but they seem make it work :wink: .

subcritical71
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Re: Honda Power Unit Hardware & Software

Post by subcritical71 » Wed May 22, 2019 3:33 pm

I was curious, so I went googling and found this article on the development of the TAG-320 from 2012 :shock:

https://www.rbracing-rsr.com/downloads/ ... ag_320.pdf
The ecu is at the heart of an F1 car, providing complete control over the powertrain. It works with slave units to control ignition and injection for a V8 engine, as well as controlling throttle by wire and clutch by wire functionality. In order to do this, it takes data from something like 130 sensors around the car. Accuracy is crucial; F1 engines run at up to 18,000rpm and the control strategy can recognize crankshaft positions to an accuracy of 0.027deg.
The ecu's main control strategy runs on a 1ms time step.
I would assume the ignition control unit would be faster than this :-k .

Additionally it was mentioned gearbox strategy is timed to 0.1ms

Brake Horse Power
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Re: Honda Power Unit Hardware & Software

Post by Brake Horse Power » Wed May 22, 2019 9:37 pm

@bandit, the speed of an electronic signal is not the problem, but a sensor digitizes a measurement, which takes time. A computer needs to decode it, do something useful with it and send to the next station. That takes some time.

So the wheelslip will be measures at each rear wheel right? Using the crank signal would have a far greater accuracy because of the reduction in between but the diff messes up this reading to derive the exact wheelspin from it. You can debate how accurate the system should be since the diff might have some will of its own. (unless you have diff magic).

So if you want to have a reading for each wheel, the measurement should be something like this:
Wheel diameter, 0,67m (at 0km/h!) = 2,1038m circumference.
At for example 100km/h, vehicle speed = 27,77m/s. = 0,0277m/ms. = 4.7 degrees wheelturning per millisecond. If you measure per degree of rotation you will get 4 pulses per millisecond. At 200km/h its half of that. The measurement rate to see when the puls is should be something like 10kHz at least. This corresponds to the 0.1 ms strategy as indicated in previous post.

So in theory this might be possible, BUT you will measure every bit of deflection, tiny losses of grip etc. I wonder if controlling an mgu-k to this level is practically possible. Somewhere you will need kind of 'low' pass filter to not be reacting to every miniscule event.

gruntguru
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Re: Honda Power Unit Hardware & Software

Post by gruntguru » Wed May 22, 2019 11:47 pm

Brake Horse Power wrote:
Wed May 22, 2019 9:37 pm
So in theory this might be possible, BUT you will measure every bit of deflection, tiny losses of grip etc. I wonder if controlling an mgu-k to this level is practically possible. Somewhere you will need kind of 'low' pass filter to not be reacting to every miniscule event.
I doubt the response of the MGUK would be fast enough to react to the "minuscule events" you refer to. The inductance of motor windings effectively inhibits rapid changes in current.
je suis charlie

Tommy Cookers
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Re: Honda Power Unit Hardware & Software

Post by Tommy Cookers » Thu May 23, 2019 12:28 am

for best control response (and best efficiency) the inductance would need to be minimised
(this has practical disadvantages and so is not for general purposes)

in this way the time for the MGU-K's full response of torque internally will be c. 5 millisec - the electromagnetic time constant
this response will be delivered externally if there is no rpm acceleration or acceleration torque is of external origin
eg wheelspin from K + ICE torque could allow K torque to reverse fully within 5 millisec
(accelerating itself the MGU-K's full response externally will be c. 40 millisec - the electromechanical time constant)

these values are taken from an older 5 kW machine - assuming the K's modernity and size give no net gain or loss
time constant was the time for 63% of a step demand to be realised - this for brushed machines
modern machines won't be given step demands - but the response is in principle the same as a brushed equivalent

henry
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Re: Honda Power Unit Hardware & Software

Post by henry » Thu May 23, 2019 6:55 am

40msec would be the best part of a metre at the speeds we are considering. That would seem pretty slow for controlling wheelspin.

Edit: and it also seems slow for gearchange duties as discussed earlier in this thread c
Fortune favours the prepared; she has no favourites and takes no sides.
Truth is confirmed by inspection and delay; falsehood by haste and uncertainty : Tacitus

NL_Fer
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Re: Honda Power Unit Hardware & Software

Post by NL_Fer » Sun May 26, 2019 6:52 pm

Hamilton blazing away in the tunnel and straight. Honda was still missing power.

Sieper
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Re: Honda Power Unit Hardware & Software

Post by Sieper » Sun May 26, 2019 7:29 pm

Agree, allthough you have to account for the one in front being able to start accelerating earlier. Lets hope Honda can still find more horsepower.

Bill
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Re: Honda Power Unit Hardware & Software

Post by Bill » Sun May 26, 2019 7:42 pm

Having good traction is equally important Hamilton being on the softer tyres helps only the front was in bad shape

GerryTT
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Re: Honda Power Unit Hardware & Software

Post by GerryTT » Sun May 26, 2019 7:54 pm

NL_Fer wrote:
Sun May 26, 2019 6:52 pm
Hamilton blazing away in the tunnel and straight. Honda was still missing power.
And “mode 7” didn’t change that.

restless
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Re: Honda Power Unit Hardware & Software

Post by restless » Sun May 26, 2019 9:10 pm

Actually after "mode 7", Verstappen was staying much closer in the tunnel.
Even though, Hamilton was using Mercedes "max power mode" too.

loner
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Re: Honda Power Unit Hardware & Software

Post by loner » Sun May 26, 2019 9:24 pm

Honda is lacking power every body know that.. all eyes on their next update...
It Tolls for Thee.