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rebekah_harper

advice for help

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Hiya all,

 

I have a project that I want to complete but not sure where to go for technical advice.  I have posted on Adruino forum but wondering where else I can go. 

 

many thanks 

 

rebekah anderson

 

this is the project:



I am building a RC Crane and I am going to use a stepper motor to control the telescopic boom in the way the real crane does it.  the mechanics of it is fine.  I just need to figure out how to create the electronics. 

I know what I want it to do but I am not sure how to achieve it or if it's possible.  I do a lot of 3d printing and am looking at using similar principles. 

I have attached the design for one of the modes which is boom control created using inkscape.  I also want to make a drive control and a stabiliser control mode.  the principle input out put is based on normal Radio controlled transmitter where the above is integrated. 

It will be a fully customised transmitter so dismantling and rejigging things is accepted.

Boom Control Mode:

The way the boom works on the real thing is each section is pushed out one at a time (see attached image).  inside there is a single hydraulic ram that moves a hitching block that locks into a boom section, then releases the boom section from the next boom section via a locking pin. moves it up to a new position (there are 3 positions it can go to for each section) locks it into place and the hitching block unlocks from the section and retracts to the next boom section to lock into it and release it.  this is then moved to the next position pushing up the previous boom section along with it etc...

so with the stepper motor I can program each boom section's home position for pick up by the hitching block and I can also program each locking pin location so it knows where to go in order to re-lock the boom section into place. 

the attached image shows three buttons for each boom section indication the three positions the section can extend to. I have also included read outs for each section and a total. 

1) Can I integrate a TFT touchscreen with adruino board into a modified RC transmitter, use a channel or more to control the boom over 2.4Ghz. and use a stepper motor and an adruino board programmed with the functions I need. I am sure that I can achieve feed back to represent the readouts.

2) Can each move made by the stepper motor be remembered so when I press home it will know the last location of the boom section and go to it lock into it and bring it to the home position. 

3) Can it be set up so that if two or more sections are extended that if I press home on a boom section that is further out than the stepper motor can go to that is will home the the sections in revers order until it has home the requested boom section. 
Or
Not do anything apart from reporting that it is an invalid command because it's too far out. 

4) If the above is possible, what components would I need to achieve this.  ignoring cables and connectors, but what boards would be able to carry out the processing of the script, what TFT screen would be ok and what would I need to run the TFT Screen as a touch screen to the suggested board. 



I think I have conveyed the idea I want to achieve, but as with all things it makes sense in my head so if I have lost any one who is willing to help let me know what I need to explain further and I will be happy to do so. 

Many thanks 

Rebekah Anderson

Boom function.jpg

Touch screen design.png

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Hi Bex,

 

Ok, what scale are you printing at? I ask because I just went through a gazillion design iterations to get a crane model to print out without it having to look cartoony by way of beefed up parts.

 

I found it impossible to build to actual scale because the reduction made walls either too thin or flimsy. It was a lot of back and forthing on the prints to get an aesthetically pleasing model that did not look out of whack.

 

I did manage, but am wondering if you have considered this part of the  project or not.

 

I cannot help you with the electronics yet as I am not far enough into that to help with stepper motors.

 

But, have you considered a worm gear instead?

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Hiya,

 

thank you for your reply.

I design my parts in the scale I look to have. Applying tolerances to avoid exactly that.  You’re so right and have tried to find ways around these issues. 

 

The post is mainly aimed at the electronics aspect.  The boom is going to be made out of metal for the reasons you mentioned but most of the entire crane is going to be printed.

 

the stepper motor is going to have a lead screw to reproduce the linear travel.

 

i know guys on here are all over scripting, adriuno boards and programming so am hoping someone can point me in the right direction.

 

regards

 

Bex

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I didn't get what you actually want to do with the electronics part? 

What do want actually (electronics speaking), drive a motor (dc or brushless)? or a servomotor? please attach the links of the components you are thinking of so I can explain to you. or even better a small schematic (on paint) with just the electronic parts and how they interact with each other

 

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Something to consider is that you will not have a feedback with usual RC controls.

I would also add mechanical switches to know where your start is (just like 3d printer if you noticed, every time the printer starts , it gets its zero position going to the mechanical switches.

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Hiya swissengineer,

 

Thank you for the video. Although not what I was aiming for but I have been looking for that before so very useful. ?

 

well I’ll I was hoping that the initial post was a good explanation but easy to say for me as it’s in my head.

 

here goes:

 

As you can see the boom is telescopic. However LIEBHERR uses a different system to that of others. The telematic system extends from the inner most section as the first to the outer section last. Each section is pushed by a single ram. This locks into the base of the section and moves it up the boom to one of three points.  Once the desired position is reached the section is locked in place and the ram is unlocked from the boom section. The ram would the move to the base of the next section and same process is run until the total desired length is reached. 

 

I the model, the same process is desired.  Using a stepper motor in place of the ram. This will give me control over the distance the motor will move.  Using a board I should be able to program every position referencing home positions for each section in the fully retracted position. 

Further more I want to add as part of the script a conditional that allows the pins to be moved only when in position. 

Further more I want to use a touch screen to control the boom.  

I am hoping that the board can retain last known location for the boom.

 

The two images show the TFT screen layout and the other is the real boom setup. 

 

I think im going to have to build transmitter and receiver instead of using an existing Rc set.

 

i will add a switch as you described either at the base or last boom section base.

 

theres a lot to learn and understand but I’m happy to do it. I am trying to find tutorials but finding the right ones is proving a challenge. Stepper motor is on the way with driver but not sure which Adruino board to use for the vehicle and for the transmitter. I’ve seen the transceiver modules which look fine.  I do need to be careful as I will be operating with other RC drivers. So I need to how how can employ spread spectrum and using a start flag on the transmission to link in with my receiver. 

 

Motor

 

Transceiver

 

I also want to add 2 more pages to the TFT touchscreen for different modes which will allow to select steering mode and the other the outriggers.  There will also be stick controls on the transmitter.

 

hope I managed to convey the idea.

 

many thank

 

Bex

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I think you should start first with two boards, one master and one slave, connected through an UART communication. Your Master board with your touch screen , and your slave board with the motor and other peripherals. Then when everything works perfectly, I would add the wireless feature. 

Wireless is not as easy as it sounds, and can be a pain to program and a pain to debug, so first be sure that everything works before going wireless.

Finally I would not go into 2.4ghz necessarily, you have many other options that can be much simplier , like zigbee, bluetooth, radio etc...

To resume:

Go to the essentials first! Make sure everything is set up, all you registers that are exchanged, all the electrical parts also and finally go wireless. I forgot to mention that , it exists some modules that enter with a simple UART then transforms it into a complicated wireless protocol then back to an UART in the other end.

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Thank you so much. The advice is what I was looking for. It gives me direction. Am getting to know the script writing for Arduino and the principals seem simple enough. I just need to build up on the codes and their functions. I am pretty sure there’s is coming to be plenty of conditionals in my script and it’s going to be very long but I love the possibilities. 

 

I will I’ll research what sort of wireless options there are and which is going to be most useful. 

 

Considering the the amount I want to be able to do, what board would be best to use. I was thinking Mega but I am still making my way through their capabilities.

 

I now have a mini project that is being supported by a friend for the national RC truck gathering. 4 way junction traffic lights.  Code should be simple enough and  I will use relays so I can have multiple LEDs running. Without stressing the power for the board.  

This will give me a chance to practice some loops, delays etc... 

 

Other than the Arduino site and YouTube is there anywhere else for learning resources.

 

many thanks

 

Rebekah Anderson 

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I've also got another idea, if you don't need a really really fast connection, you could use a smartphone as controller, and one arduino for the crane with a bluetooth shield and a small controller board like in the video for the stepper. I think this would be the simpliest way.

 

 

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hiya,

 

it is, I am building a 1/14 scale version.  the boom reach at maximum is 3 meters without the fly jib. 

 

the boom sections are working well, although I could do with fine tuning their assembly but using piano wire and fixing them into the boom under tension seems to work well. 

 

bex

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