Rodeown

Whilst hunting for a soloution to my rear steer trailer problem I came across this Rubiks solver By David Gilday. It is much faster at solving than the Tilted twister that I built when i first got my NXT set so I just had to build it to see how it performed, it managed a 2 minute solve in my video.

That is a good option, I am thinking to put my steer trailer on hold for a while and get back to it when i can get my head around it some more, I did come across a company called Mindsensors that make some interesting sensors for Lego NXT mindstorms, they are developing an angle rotation sensor at present and it would be perfect for my trailer use but i have to wait till they go into production, here is the link to them anyway Mindsensors upcoming angle sensor

wow nice

well after extensive testing on the trailer using the nxt motor as a rotation sensor i have found a problem, the motor, whilst it can be turned freely by hand it suffers from a "cogging" effect so when connected via a pin to the tractor unit it turns in steps rather than smoothly (probably why hitechnic designed a non resistance angle sensor) so to steer the trailer via this method i will need to buy an angle sensor. Moving on, the colour sensor might be a better option because then i am not relying on a tight held hitch connection and the colour seen under the sensor will instruct the nxt brick to move the steer motor accordingly, so back to the drawing board for more testing.

Jadedomg, I can understand fully what you get from lego, i only found it this year and it has changed my life, as you state that feeling of been able to do something again is a very good feeling. It is nice that Grum64 and yourself have lego to challenge you and give you goals to aim for, I go to a pain management clinic and they teach us to find things that occupy us and challenge us at the same time, this supposedly helps distract from pain and your problems and gives you the feeling of achievement that everyone requires . Thanks again to Grum64 for starting this thread as it is allowing us to share and know that we are not alone.

Yeah maybe,trouble with more gears = more backlash which i am trying to get rid of IE reason for NXT use, but if i get the NXT idea working then i can set the amount of steer at each stage of the turn to what is appropiate so for example i could take the output from the rotation sensor and increase it in a math block through lets say 20 to 60 degrees then back to normal through the rest, this would open many options for the control of the trailer, maybe even an nxt switch on the truck that triggers during reverse to provide a reversing siren "backing up Backin Up" I could also add a switch for the trailer tipping aswell maybe! Yeay i Love lego! STOP THE PRESS. edit just managed to get the rotation to transfer to the other motor. (corrected the sound issue i had on this video.)

Alasdair, the problem isnt about what motor to use in the trailer but about how to sense the trailer is turning and how far it has turned so the motor at the rear could adjust the rear steer accordingly. Anyone could make a rear steer that requires input from the user on a controller, what I am attempting here is unattended rear steer that is progressive and works correctly. Someone suggested linking it to the front steering but that wont work because there are so many occasions when the truck is steering opposite to what you need the trailer to steer. I am confident that I/we will find a soloution, I am not someone who gives up on a problem.

Thanks TimH, Okay Lego NXT experts i need some assistance, I want to use motor A as a rotation sensor so that Motor B matches it exactly, I have spent many hours trying to work outhow to do this but not found any answers yet, the closest i have come to finding a soloution is in the video below at the 8.00 minute mark but that would entail the purchase of a Hi-Technic angle sensor, I am sure it can be done with a normal NXT motor used as a rotation sensor as they output the degrees of angle -/+ as they turn i just cant work out how to transfer the position of A to B anyone got any ideas? Here you go Tim, hope its okay i will do a small video as well with the hitch off the truck so you can see the underside of it. video finished now

Yeah if you look at my earlier vid 3rd post on first page of this thread i have built a working rear steer trailer earlier this year, it worked really well but the axel distance was a short run as in the video you posted, my new trailer is twice as long and as such has twice the backlash of the shorter run so i will have to use a different method. but thanks anyway. Hey Gilby, Thank you for taking the time to do this, after pushrods were mentioned i did my own small test but realised that it wont work because a trucks trailer can turn more than 90 degrees in some situations so the push rods would come to the limit very quickly, not sure how to get around that because a clutch in it would cause problems as the trailer would go out of sync with the tractor unit. I am trying to get my head around the NXT sensors and motors at the moment i have few ideas but will test them first.

Video of truck and trailer prototype in action, ill let the video tell the story

lolz at above ^ Well i did some testing with a rear steer trailer on my hitch system but have hit a problem, my steer trailer uses axles from the hitch to the rear wheels to steer the trailer around the corners, whilst this seems to work okay on a small trailer when i attempt it on a longer trailer it fails, reason been "backlash" to much play in the axels and gears so when back to straight the wheels on trailer are still slightly turned. I am now thinking the trailer needs to be NXTeed with a colour sensor reading a scale on the truck fifth wheel as the trailer turns and turning the wheels accordingly, i will have to do some testing and see what i can do. Its great fun driving round with a trailer though.

Thanks Tim, It does look good doesn't it the problem with the hitch is that my self steer trailer uses a pin that needs to lock in a fixed position on the tractor unit so it steers the wheels of the trailer so 2Lego's is not suitable. I have spent many hours today making different designs of hitch and have finally come up with a working design that will be able to be hitched by reversing in with no manual intervention and also will be able to be unhitched with out manual help, I hope it works but only time will tell, now to make a prototype trailer to test my hitch design with P.S. I also have to make seats dashboard and steering wheel, I hope you noticed the working 8 cylinder engine in the pictures!

I understand the comments above but everybody is different, I personally like to fix mistakes before moving on and make sure that I dont have to take it completely apart and rebuild it again. I find it hard to actually put lego together and take it apart as i have no feeling in my fingers due to peripheral nerve damage. As such I am asking for help from experienced builders so that i have to rebuild as little as possible, still the chassis was taken apart and rebuilt many times before i was happy with it, the cab has been rebuilt 7 times now. If I had not been showing the developement of this truck then GMshades would not have seen my steering that he wishes to incorporate in his own model,(which i am thrilled about) also the subtitle of the thread is WIP work in progress. I will not post any more progress on this work from now on if it displeases you as i dont wish to upset anybody as i have not been a member of this forum long and dont want to rock the boat. Thank you for all the help and great comments people.

Noo no please keep making constructive comments as i am relying on them to create a great MOC altough we may have to rename it as a MAAOC "mine and Alasdair's own creation"

some folks are hard to please Yes I understand the sunroof idea in a yellow roof, problem is i need a yellow flat panel, I have added some yellow curved panels in place of the black just to give me an idea what it will look like though.

Thanks for that will keep the windscreen shape Taken a look and seen what you are thinking, thanks again for the help everyone, here are todays latest pictures I have lowered the cab by one yellow stud as it was to high above the upper black line, widened it by 2 studs to allow the use of the curved panels as per the style of unimog that Alasdair suggested, completed the roof and fitted the IR receivers into it so they look like part of it. Now need to strat working on the interior with some seats and maybe a V8 working engine, not sure about the engine yet but there seems to bee enough room to fit one between and under the seats, aldso need to creat dashboard and steering wheel, not sure if the wheel should turn with the steering or just be a false one. All I can say is that I am really enjoying this build and can now see why you people spend so much time doing this

I have not been in to Technic long but i would suggest you build your own model from scratch incorporating functionality and good looks, at present i am building a truck and could have taken the easy route and motorised the 9397B model to do what i wanted but I am having so much fun and satisfaction out of building and modelling my own creation that i would not reccomend any other route, the people on these forums are so helpful and have come across many of the problems you will come up against, so just go for it, and enjoy it aswell, there is no rush, i put in a couple of hours a day and am very happy with the input of others that know more than me to help me create an awesome MOC. Good luck with your build

Tried what you said but it looked wrong, spent some more time on it please give more feedback, trouble i have now is i am going to have to order some parts. also wondering if the front screen needs to be straight up and down instead of leant backwards slightly? *EDIT* I have just been sat here comparing it to the DAF CF picture and decided I am trying to build the yellow too far back over the wheel, the original only goes to just beyond half way over the wheel so i may do a rebuild, also noticed that the yellow above the black at the front is probably one stud too high, so i think i need to start again on the upper part.

starting to think you dont like those yellow panels above the wheels ?

Oh mama mia This is amazing Sariel, that cow catcher on the front looks like it would do its job no problem "its soooo Shiny!"

Alasdair, Yes i wasnt happy with those, done some more on it now, turned them the other way up which gives me the step in on the cab that i was after, IMO it looks tons better started working on the windows area now trying to get them looking right, main problem i have now is i am running out of the yellow beams that i need to build this.... oh well hopefully lego will read this and donate a load of spares cause i dont have much money left in my lego fund after what i have spent this year on sets. it is hard having to make do because you are short of one little piece ! Anyway here is the latest update, Thank you everyone for the great comments on how to make this better, please feel free to keep them coming as it is starting to look something like what I imagined originally, I am wondering about the lights, maybe need to raise them up a stud so they look more like the original, I have to redoo the steps anyway so might get to that next time i feel like been challenged.

agree with you i do, already removed em, decided exactly the same thing.

just spent some time redoing the section above the grill to get it looking more like a DAF CF cab and added some panels just to give me inspiration, I will sit looking at it for hours now trying to decide what it needs. GuiliuG, yes it would look better you are right, only problem is it is structural atm, maybe need to rebuild that part again. still trying to get the cab looking similar to this DAF CF

Thank you for the comment, I am actually limited to the parts i have available, I dont have those pieces in red and certainly dont have any red axels !