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Old 18th July 2014, 15:19   #46
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Default Re: The End of Left-Foot Braking? BTO - Brake Throttle Override

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Originally Posted by Rehaan View Post
... How does a stepper know its position / prevent any kind of drift? Being an open-loop system I'd imagine this could be more dangerous? ...
Zoom out a bit, and you should realize that the actuator that controls the throttle flap gate is not an independent control system by itself, to warrant the term "open-loop" or "closed-loop". The actuator, and it's coaxial position sensor, form a part of the throttle control regulation loop (closed loop control). The actuator doesn't drift by itself, or even if it does the incremental error is miniscule. Air flowing past the gate exerts enough force to possibly cause an error, which the control loop normally corrects.

The most likely danger involved is gate shaft jamming due to contaminants and dust / dirt. That jamming is fine if it is at a position less than desirable (will show up as power loss), but if stuck more than desirable it can cause a runaway in some conditions.
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Old 18th July 2014, 16:02   #47
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Default Re: The End of Left-Foot Braking? BTO - Brake Throttle Override

Just my 2 cents to the pond...
Drive by wire is an intelligent closed loop system to relate gas pedal position to speed.

Either Servo or Stepper motor is a part of the above sub system. Both of them can be used to set desired throttle position valve by ECU

Among them, stepper motor is a open loop system and servo is a closed loop system uses a simple DC motor.
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Old 18th July 2014, 17:13   #48
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Quote:
Originally Posted by DRC View Post
Among them, stepper motor is a open loop system and servo is a closed loop system uses a simple DC motor.
Whether a system is closed or open loop is not decided by the type of control mechanism. It depends on whether the system has a feedback signal in this case a throttle position sensor.
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Old 18th September 2015, 13:29   #49
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Default Re: The End of Left-Foot Braking? BTO - Brake Throttle Override

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Originally Posted by Rehaan View Post
In other words, expect cars to become more safe on the roads, and less fun on the racetrack.
10 major automakers (namely BMW, General Motors, Mercedes-Benz, Toyota, Volvo, Tesla, Volkswagen, Mazda, Ford, and Audi) , collectively accounting for 57 percent vehicle sales in 2014 in the U.S. have committed to making automatic emergency braking standard on all their new vehicles in the U.S. !
Link: http://www.dispatchtimes.com/automak...ehicles/93146/

Last edited by HolyDriver : 18th September 2015 at 13:46. Reason: typo
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Old 18th September 2015, 15:56   #50
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This is sad news in general. I don't mind this system in automatics ( those without clutches), but in cars that have a clutch - manual or automatic , can simply disengage the clutch.

Also left foot braking is useful to keep the engine in turbo range when you have to take a take a turn or slow down.
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