Automatic creep makes it impossible to come to a smooth stop

[Jaff]

PopSmith, I agree wwith your thinking 100% on this...to me, it is more of a liability issue (for TMC) than a convenience / in convenience issue for Roadster owners...remember, we will have new EV owners (some who don't / won't read manuals)...it is important not to leave any loose ends that may cause even the dimmest of the dim new EV owner to screw up whilst operating their vehicle...as sad a comment as it sounds, there is a reason that ICE lawn mower manuals advise you to not pick up your running lawn mower to trim your cedar hedge.



I'd also support this (creep to be shut off by the vehicle owner at their pleasure) 100% as it proves a "conscious decision / action" by the vehicle owner to in fact shut off the feature...it would / should mitigate TMC's liability exposure from this issue imo.

 

[Doug_G]

So might being shoved further ahead completely through an intersection and out of crossing traffic. Kind of hard to predict what's best at a particular moment in time.

That's a silly way to look at it... no matter what, I'd prefer to move 5 feet rather than 50. Being shoved into an intersection must have a 100X higher probability of a secondary collision.

When sitting at a stop light, you shouldn't be holding the brake pedal lightly. You should have full weight on it.

 

[vfx]

I know it's been a few pages but Stuart's original Post was brilliant:

Automatic creep makes it impossible to come to a smooth stop
Below is a suggestion I made to the good people at Tesla. They requested I post it it to the teslamotorsclub forum because they're interested in seeing how much support there is from other people.

I like to drive well. One of the things I was taught when I was learning to drive is that if you're in control of your vehicle then you should be able to bring it to a smooth stop without any perceptible lurch, by gently letting off the brake pressure as the vehicle slows down to a smooth stop. In a manual transmission car if you depress the clutch pedal and brake properly you can do this.

For design reasons I won't speculate about, the Tesla Roadster was designed to emulate an automatic transmission. With no pedals pressed, if it is in drive, it will slowly creep forward, presumably to remind the driver that it is still in drive. However skillful you are on the brake pedal, if the car's motor is trying to make it go, it becomes impossible to bring it to a smooth stop without a small lurch.

I have read discussions about disabling this "automatic creep", but I'm realistic enough to realize there are probably good reasons Tesla wouldn't want to do that. (I have also read discussions about hacking firmware to disable the "automatic creep", but I don't want to do that.)

This led me to wonder if there could be a way that car could let the driver stop smoothly without having to disable the "automatic creep" and a compromise occurred to me: If my foot is on the brake pedal, and the brake lights are illuminated, then the car's electronics know that I'm trying to bring the car to a stop, so why are the car's electronics fighting me and trying to make it go? Would it be possible to make the car's electronics disable the "automatic creep" as long as the brake pedal is depressed? That would allow the driver to bring it to a smooth stop. If the brake pedal is then released then the "automatic creep" would resume, to remind the driver that it is still in drive.

Does that sound like a sensible compromise, to allow good drivers to drive well, while still retaining the safety requirements of "automatic creep" so that driver's can't forget that the car is still in drive?

And my comment:

Really thinking about this it's a very good refinement of what Tesla is doing and is right up the ally of them trying to make a car that is the best on the road.

So the problem is when we are coming to a stop at the very last 1 or 2 miles an hour the creep takes over changing regen's somewhat linear downward speed ramp to a straight line speed before it can complete it's path to a complete stop. Since there is no way to predict exactly when it that flat line will "jump in" you can't react fast enough and change your braking amount to the new speed to achieve an ultra smooth stop at that very very end of the braking.

Another solution would be to not have creep come on till after the car comes to a complete stop BUT,

As a certified "creep hater" what I don't like about it is when sitting at a stop light and you relax your brake foot a bit the car starts lurching forward. Even with the brake light still on.

So yes, your idea works for me as a solution that is closer to what I want than we have now. Who knows, I may even like it in practice.

As long as the brake lights are on, creep is disabled. It would make for ultimately smoother final end of braking and make the car not be too anxious to move forward when slightly letting off on the brake while stopped.

I find this to be superior to an AT ICE car. Tesla should implement this on all cars past and future.

Good thinking!

On my list of things that I should have talked with JB about (at the X EVent) this should have been number one!

 

[eledille]

I hate creep. I also hate jerkiness. My ICE car has a hydraulically actuated manual gearbox, and I imagine it spoils my chauffeur stops in almost the same way as Stuart describes: While decelerating, the computer will automatically disengage the clutch when RPMs fall slightly below 1000. That suddenly removes the engine drag, causing the rate of deceleration to suddenly change. It's annoying. It doesn't interfere with the actual final stop, but it's annoying nonetheless.

My EV is super silky smooth in all situations. I love that. It's also extremely easy to maneuver at low speeds, the power control is so fine that I can move 1 cm forwards. I can't see the problem. How can it be hard to get used to that the car doesn't move unless you tell it to? Regen on the accelerator just means that the car tends more quickly towards standstill with zero input, which feels natural, so that's fine.

mpt: What's next? A stink generator so no one will miss the smell of fresh exhaust in the morning, I bet :-D

Wishlist:

1) Remove creep entirely. Have the car generate annoying sounds or shift to neutral instead.

2) See above.

3) Failing the above, kill creep whenever the brake light is on.

This can be user configurable as long as the car supports multiple user profiles and can select the right one automatically.

 

[djp]

I've always driven manual transmission cars so by nature I also hate the creep, but I understand why Tesla did it. The creep isn't there to mimic an automatic, it's there as a safety feature that results from having regen on the accelerator.

It's very easy to single-pedal drive a Roadster and come to a complete stop using regen alone (if creep was disabled). This would make it tempting for lazy drivers to keep their foot on the accelerator at stop signs and stop lights - which needless to say is extremely dangerous. By including creep drivers are forced to take their foot off the accelerator and hold the brake at stops. Manual transmission ICE cars don't carry the same risk - without regen you can't come to a complete stop using the gas pedal alone.

The only safe way to disable creep would be to move regen to the brake pedal, but that would take away the fun of single-pedal driving a Roadster. I think Tesla made the right compromise.

That said, the topic of this thread is creep on the brake pedal which makes it impossible to come to a clean stop. I agree completely that creep could and should be removed from the brake, and only kick in when the brake is fully released.

 

[zack]

In manual transmission cars you can put the car in neutral when at a stop and you've got the same situation as no creep. The Tesla can be put in neutral while stopping as well.

 

[JRP3]

Since Tesla uses a single speed gear reduction I assume "neutral" just means no response to the throttle, and not a mechanical disconnect?

 

[woof]

I got a peek at one of the ActiveE training manuals. There is no clutch in the transmission. Instead it explained that neutral is achieved in the ActiveE by supplying a voltage to the motor with the phase/amplitude controlled such that there is no torque generated.

I'd wager the Tesla motor control is similar.

 

[zack]

My Roadster is in storage for winter, but I'd wager that when in neutral, it does not creep. It makes no logical sense for any car to move when in neutral and at a stop, so creep must be canceled in that mode.

BTW there's also tow mode, which does mechanically disconnect some part of the drive train, if I understand correctly. But obviously tow mode is of no use in this context.

 

[eledille]

I've always driven manual transmission cars so by nature I also hate the creep, but I understand why Tesla did it. The creep isn't there to mimic an automatic, it's there as a safety feature that results from having regen on the accelerator.

It's very easy to single-pedal drive a Roadster and come to a complete stop using regen alone (if creep was disabled). This would make it tempting for lazy drivers to keep their foot on the accelerator at stop signs and stop lights - which needless to say is extremely dangerous. By including creep drivers are forced to take their foot off the accelerator and hold the brake at stops. Manual transmission ICE cars don't carry the same risk - without regen you can't come to a complete stop using the gas pedal alone.

Can't this be achieved by softly fading out regen as speed approaches zero? My EV has an AC induction motor like the Roadster. It has practically no regen force left at walking speed, so you have to use the brake to come to a complete stop. This is by design and not just a feature of AC induction motors. Also, there is very little energy left to regenerate at such low speed anyway.

The problem can also be solved by having the car generate a sound and/or select 'P' if it is in drive, the handbrake is off and it has been at standstill without brakes applied for more than X seconds.

My Alfa Romeo Selespeed is also freewheeling in this situation - in first and second gear, whenever the speed is so low that the current gear would force the engine below idle rpm, the computer disengages the clutch. It has no regen, of course, but the automatic clutch means that it's possible to forget that the wheels can spin freely. It will emit a double beep and select neutral when you let it sit for 60 seconds without holding the brake, and immediately if you open the door. If you open the door, then select a gear it will only stay in gear for about 10 seconds before beeping and selecting neutral again.

I think the 60 seconds the Alfa waits before beeping and selecting neutral is too long. You should never do this anyway, so five seconds before emitting a little beep and selecting 'P' would be just fine. That would teach people to drive properly.

 

[JRP3]

BTW there's also tow mode, which does mechanically disconnect some part of the drive train, if I understand correctly. But obviously tow mode is of no use in this context.

I would guess that tow mode simply releases the parking pall and kills the power to the inverter which would allow free wheeling when the motor turns, I don't think there is any way to disconnect the motor from the wheels.

 

[JRP3]

Can't this be achieved by softly fading out regen as speed approaches zero? My EV has an AC induction motor like the Roadster. It has practically no regen force left at walking speed, so you have to use the brake to come to a complete stop. This is by design and not just a feature of AC induction motors. Also, there is very little energy left to regenerate at such low speed anyway.

I have my AC induction motor set similarly, it usually takes a little brake pedal to come to a complete stop, though not at low speed on the flat, so I can still single pedal most of the time in stop and go traffic.

 

[S-2000 Roadster]

I wish it was like a Segway and would just hold its position whether you're on a hill or not. As it is, if you are stopped on a hill the car will roll backwards which is just ridiculous. Make creep the default but let us turn it off.

Why would you want to drain your battery to keep your car on a hill? I just use the brake, and I've never rolled backwards. It's also nice to see the current drop when you apply the brake.

 

[S-2000 Roadster]

At the very least the ability to turn it off (and keep it off) is a must.

Creep can be turned off by selecting Neutral. Look for the button labeled 'N' on your control panel. You don't even have to apply the brake for this transition.

 

[S-2000 Roadster]

If the brakes are engaged at a stop light/sign (due to creep) then the car won't hit the person in front of you in the event of a rear collision.

In the event of a rear-end collision, you would prefer to have your foot off the brake. Less damage will happen to you and your car if the energy of the impact can be absorbed by moving your car forward rather than by crushing your car or you inside your car. Obviously, this ideally requires that you leave enough space between you and the car in front of you so that you don't hit them, too, otherwise you'll be crushed anyway.

 

[stopcrazypp]

In the event of a rear-end collision, you would prefer to have your foot off the brake. Less damage will happen to you and your car if the energy of the impact can be absorbed by moving your car forward rather than by crushing your car or you inside your car. Obviously, this ideally requires that you leave enough space between you and the car in front of you so that you don't hit them, too, otherwise you'll be crushed anyway.

I think in at a stop light/sign keeping the brakes applied is better. With the brakes off you will likely hit the car in front (even with a reasonable distance away from the front car), which means front AND rear damage (as well as two collisions). The other big danger is losing control of your car and being pushed into oncoming traffic or cross traffic or pedestrians or other obstacles.

As for the physics argument, supposedly having the brakes applied means less overall acceleration for the passenger and less risk of injury (even if it means more rear damage to the vehicle).
http://forums.randi.org/showthread.php?t=227726

 

[daniel]

... most people (at least in the U.S.) are used to driving ICE-powered automatics. [... C]reep [...] is an attempt to keep people as "comfortable" as possible with the transition to an EV. [...]

If the brakes are engaged at a stop light/sign (due to creep) then the car won't hit the person in front of you in the event of a rear collision....

The Roadster is a sports car. Most sports cars have manual transmission. So I would think that most Roadster buyers would "expect" or would be "used to" no creep. Neither my Xebra nor my electric Porsche have creep, and I like it that way,

The wife of a friend was rear-ended. The car was an automatic and so she had her foot on the brake. Her car was thrown into the car in front of her hard enough to do serious damage to the car, and she had neck pain for several months. (She is well now.) Most people, stopped at a light, do not apply sufficient pressure on the brake to hold the car if it's hit from behind, and probably don't have the presence of mind or reaction time to apply full pressure at the instant of being struck.

 

[mpt]

When you're hit from the rear and are not expecting it, your body will move backwards releasing the brake IMO.

The MINI E and ActiveE drive more smoothly as a result of no creep - it's just nicer.

 

[mpt]

Time for a poll - let the community decide!

 

[howabout2]

No creep, please.

I wonder if any of the former MINI E drivers or current ActiveE drivers would prefer creep. I'm guessing no.

You become acclimated to no-creep in just a few minutes because it's so natural as a human-being. Do you keep moving when you elect to stop walking? Do you have to apply pressure on your feet to stay stopped?

Then, after turning in the MINI E and switching back to an ICE with that automatic creep, it boggled my mind. Whoa, whoa, whoa! Why is the car still moving??? I am not providing any forward input to the car!