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Trailers - driver assist


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#1 Greg Locock

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Posted 22 May 2015 - 02:55

http://news.pickuptr...2016-f-150.html

 

Oddly they didn't include the really simple function to automate hitching up in the first place. Why, I don't know. 



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#2 desmo

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Posted 22 May 2015 - 03:58

Learning to back up a boat trailer is maddeningly counter-intuitive, it's one of those things like quantum mechanics, or macroeconomics or relationships where you have to unlearn what you thought you knew as a first step and just going with you gut will only lead to grief.  I take my dog to a park with a busy boat ramp and maybe 25% of the people who put in in there really could use this. 



#3 Chubby_Deuce

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Posted 22 May 2015 - 06:34

Huh. Cool use of parts already in the truck.

 

I take pride in my trailer backing abilities but the automatic straightening feature would be a handy timesaver.



#4 Lee Nicolle

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Posted 22 May 2015 - 10:11

Backing tandem trailers, caravans, boat trailers is simple. Even long single axle. Worst thing for me is a very stiff neck that is nigh impossible to turn very far. harder to do on mirrors.

6x4s however defy logic. Short drawbars make reversing them very hard. Normally I take them off the towbar and push it.



#5 wrighty

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Posted 22 May 2015 - 12:13

http://news.pickuptr...2016-f-150.html

 

Oddly they didn't include the really simple function to automate hitching up in the first place. Why, I don't know. 

 

Great link and thread thank you Greg. In relation to the auto hitching, i'd suspect the thought of amateur drivers reversing onto a hitch without being able to/caring to see what or who is beyond the back of the trailer would still be the main concern (i.e. shunting the trailer back without the hitch engaging). HGV drawbar hitches are more attuned to the auto-hitch concept, but they utilise a hydraulic plunger pin as the eye fits into a scoop/funnel aperture, thus assisting the operation greatly - allied to this is that the trailers have bloody good park brakes and the body of truck and trailer are usually an identical width, making lateral positioning much easier in the mirrors.

 

Still a good idea though :) 

 

Thanks.....Wrighty

 

ps - also thanks for a thread in Tech that i can respond to! haha :)



#6 blkirk

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Posted 22 May 2015 - 13:42

Back when I had a racecar, I did a lot of towing.  I never got why people thought it was hard.  The two axles of the tow vehicle plus the axle of the trailer form a system.  If all three axles point to the same spot (think of it as a three-axle ackermann), then you will maintain the radius of your turn.  If you want to get out of the turn, you have to speed up the turn on the tow vehicle to get it ahead of the trailer.  If you want to tighten the turn, you straighten out the tow vehicle so that the trailer can get ahead of it.

 

It's just like balancing a stick on your hand, only in one dimension (L-R) instead of two (L-R, F-B).  Longer sticks and trailers are easier than short ones because their angle changes more slowly.



#7 Greg Locock

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Posted 22 May 2015 - 18:58

By auto hitch I meant a camera based system that would bring your tow ball under the coupling, so all you have to do is lower the coupling onto the ball using the  jockey wheel. Obviously you'd need to make sure the coupling was high enough, but that's just another camera and target, at most. I suppose one reason not to do it that way is that in the USA there's a lot of non towball style hitches. Incidentally our new kinematics and compliance rig uses cameras and targets blobbed on the wheels as its measuring system, it is accurate to a few thou.

 

By the by the SAE has introduced new methods of evaluating trailer stability, I suspect you'll see either some big changes in permissible gross combination weights, or some fancy pants hitches becoming required fitment for some weights, or some interesting electronic aids. There's an interesting tradeoff on drawbar length, longer seems like a better idea but it reduces the understeer of the combination, which is bad, but increases the damping, which is good.  Here's a nice look at the topic http://www.kimberleykruiser.com/size  - note that at 60 mph (97 kph) you are getting very close to an undamped system. Ooo er. Rule of thumb is that you want at least 0.1 



#8 desmo

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Posted 22 May 2015 - 21:55

Might ESC integrated with the vehicle's acting through the trailer brakes be practical?  I suppose long haul trucks very probably already have something like this.



#9 YWW730

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Posted 22 May 2015 - 22:43

Big changes in permissible gross combination weights? Weight limits going down?

Fortuitous placement of the factory reverse camera and tow ball has simplified enormously the hitching process for me. With the trailer at the last decouple height, I can put the ball directly under the hitch every time. The reversing camera also assists with 6x4 trailer with an easy reference of the trailers position and angle when the trailer goes out of the mirrors.

On towing dynamics, I am currently wrestling with the next car trailer purchase. While I could use the family SUV it is usually pressed into duty on weekends. My daily driver has a capacity of 1700kg with a ball weight of 70kg - race car mass is 1100kg aprox. I had been thinking of getting a light single axle trailer without springs. Manoeuvrability by hand is a issue because I have a tight area to park it.

I will probably need to experiment with the balance of the loaded trailer, draw bar length and car placement with this arrangement. Views?

#10 Greg Locock

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Posted 23 May 2015 - 02:52

70 kg seems a bit light to me for that trailer, I think we're at the heavy end with 10% of trailer mass up to a max of 150 kg. Unfortunately without knowing far more about the towcar and tires on both units it really is a case of suck it and see. 

 

Obviously there's an advantage to the OEM if they can get away with a lower ball load, both in body durability and residual load available for the car - there was a bit of a fuss in Oz just recently by Mitsubishi who claimed various people were 'cheating', I didn't read the rant in much detail but from what i could see they were just 'cheating' a bit less than their nominated competitors. However, the less the ball load, the less the authority of the rear axle, but of course, the front axle gains.

 

It is an amazingly complex field, and yes Desmo, ESC for towing is coming.

 

I'll try and find some more discussion of drawbar length and towball load and post it. Incidentally in the states they've done a lot of work on the various fancy hitches that are available, mostly in terms of adding damping and front axle load recovery. All of the systems they looked at were pretty good, when used properly, typically worth another 10-30 mph. Just in case you were wondering, a fifth wheel really is the 'best' solution in most circumstances.



#11 Catalina Park

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Posted 23 May 2015 - 04:49

One of the electric trailer brake manufacturers is already marketing an automatic stability control system, basically a pendulum in a box that detects sway and activates the opposing brake to pull it straight.

Edited by Catalina Park, 23 May 2015 - 04:50.


#12 Kelpiecross

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Posted 23 May 2015 - 05:20

On the subject of how to reverse a trailer: - about 50 years ago I read in Modern Motor (I think it was) that a good trick for reversing was to note that the direction you moved the bottom of the steering wheel was the same direction the back end of the trailer went. I still find this is the best method and have always used it - even with semi-trailers.

Another good trick I have seen (and used) is if you are doing a lot manoeuvring of trailers in awkward places is to fit a tow bar to the front of the vehicle (usually a 4WD) - much simpler then.

Edited by Kelpiecross, 23 May 2015 - 05:20.


#13 Greg Locock

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Posted 23 May 2015 - 07:29

OK, short overhang is good - there's a 4 bar linkage that projects the tow point right over the rear axle, that is very effective.

 

Greasing the towball? Bad.

 

I'm going to have to run an experiment on drawbar length, the graph I want doesn't exist.



#14 YWW730

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Posted 23 May 2015 - 12:32

Actually it's 75kg. BMWs seem to have a light ball weights and there in lies the problem. I am tempted to purloin the family SUV for towing but will try it out occasionally.

#15 Bloggsworth

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Posted 23 May 2015 - 19:53

It's easier to dock and reverse an articulated lorry than car and trailer, the equal wheelbases is the problem. Docking is easier on a truck and trailer. Perhaps it will get easier with increased introduction of reversing cameras, but if the load on the trailer is correctly distributed, lifting the front to pop on the ball is no problem.



#16 Greg Locock

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Posted 24 May 2015 - 00:03

Not with a recommended towball load of 150 kg it isn't. 



#17 275 GTB-4

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Posted 24 May 2015 - 01:54

As Lee correctly pointed out, 6X4 trailers should be banned! Short draw bar, lack of visibility and any long wheelbase tow vehicle is a recipe for disaster :confused:
 
A long time ago, a wise man, who thinks about these things, once drew this mud map for me to to explain the A bar sweet spot...hint: its NOT the point indicated by the lower arrow.

Trailer%20Draw%20Bar_zpsby9geebz.jpg

#18 Magoo

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Posted 24 May 2015 - 20:27

Might ESC integrated with the vehicle's acting through the trailer brakes be practical?  I suppose long haul trucks very probably already have something like this.

 

 

Yep, already here on pickups and it works slick. 



#19 Magoo

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Posted 24 May 2015 - 20:44

Learning to back up a boat trailer is maddeningly counter-intuitive, it's one of those things like quantum mechanics, or macroeconomics or relationships where you have to unlearn what you thought you knew as a first step and just going with you gut will only lead to grief.  I take my dog to a park with a busy boat ramp and maybe 25% of the people who put in in there really could use this. 

 

 

There's a trick to it. As mentioned before in this forum, I can drive backward, with or without a trailer, better than most people can drive forward. For me it's a natural gift from the gods, but here's a couple of gimmicks to get you started.

 

First, move your hands straight down on the steering wheel from ten and two o'clock to eight and four o'clock, palms down. Then drive using ONLY the mirrors. NEVER EVER swivel your head around to look out the rear of the vehicle. From there, just drive normally using your thus-modified I/O system and muscle memory, trying not to think too much about what you are doing and that you are doing everything backward. It works, I swear it. 


Edited by Magoo, 24 May 2015 - 20:45.


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#20 275 GTB-4

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Posted 24 May 2015 - 23:51

In best Clarkson voice:

 

Some might say that Magoo has been going backwards, fast for some time!  ;)



#21 Kelpiecross

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Posted 25 May 2015 - 04:51

There's a trick to it. As mentioned before in this forum, I can drive backward, with or without a trailer, better than most people can drive forward. For me it's a natural gift from the gods, but here's a couple of gimmicks to get you started.
 
First, move your hands straight down on the steering wheel from ten and two o'clock to eight and four o'clock, palms down. Then drive using ONLY the mirrors. NEVER EVER swivel your head around to look out the rear of the vehicle. From there, just drive normally using your thus-modified I/O system and muscle memory, trying not to think too much about what you are doing and that you are doing everything backward. It works, I swear it.


Can you explain this further? I don't see how it works.

#22 275 GTB-4

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Posted 25 May 2015 - 06:05

Can you explain this further? I don't see how it works.


I believe the idea is to reduce the leverage you have on the wheel...small steering inputs have a larger effect when reversing....and possibly so your arms and elbows don't impede your mirror views.

But Magoo...everyone should be driving with hands opp one another at 9 and 3...why? AIRBAGS!

[and as I said to my Daughter who had said "but why? my car doesn't have an airbag!:

 

Do it! its all about learning good driving habits...then adding "say you rent a car, say you borrow a friends car, say a friend asks you to drive etc etc ad nauseum]


Edited by 275 GTB-4, 26 May 2015 - 10:15.


#23 Bloggsworth

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Posted 26 May 2015 - 20:34

There's a trick to it. As mentioned before in this forum, I can drive backward, with or without a trailer, better than most people can drive forward. For me it's a natural gift from the gods, but here's a couple of gimmicks to get you started.

 

First, move your hands straight down on the steering wheel from ten and two o'clock to eight and four o'clock, palms down. Then drive using ONLY the mirrors. NEVER EVER swivel your head around to look out the rear of the vehicle. From there, just drive normally using your thus-modified I/O system and muscle memory, trying not to think too much about what you are doing and that you are doing everything backward. It works, I swear it. 

 

Ah! The DAF Variomatic. I remember demonstrating to my wife and step-mother how it went as fast backwards as forwards. "Rear wheel steering," which is what you get when driving backwards is, for many, far too sudden; though a great help on fork-lifts and small dumper trucks.



#24 Lee Nicolle

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Posted 27 May 2015 - 09:12

Might ESC integrated with the vehicle's acting through the trailer brakes be practical?  I suppose long haul trucks very probably already have something like this.

ESC is bad news for towing. The stupid things want to do the opposite to what is needed. A grey haired nomad chap I know had a couple of occurences and had it disconnected. An aquaintance of his wrote off $100k plus of caravan and towvehicle because of it.

A properly balanced [loaded] trailer with decent suspension will never cause a problem. 

Bloody tortoise people often seem to defy logic on that point! Poor loading too does not improve backing trailers.

 And to my knowledge the stability control? on semis is the driver. Fancy trying to 'stabilise' 6 plus axles!



#25 Greg Locock

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Posted 27 May 2015 - 11:49

" Fancy trying to 'stabilise' 6 plus axles!" Mildly interesting challenge but i don't like doing stuff that's already been invented and analysed to death.