Programing a crane.

I need some advice.

I’m working on this massive crane with my vex. Now it’s not really a bot at this time it’s a machine. But i’m wanting to change that. Here is the projects I would like to see happen to the control module.

I’m going to have 2 control mod’s operate this machine. I want to seperate the user input from the auto behavior.

Mod 1 = User input
This mod will operate the foward, reverse, rotational platform, and raising and lowering of the hook.

A total of 4 Motors and 3 limit switches will be connected.

TXChannel 1 Platform left till 90 degrees off center then hits a limit switch to stop the turning in both directions.

TXChannel 2 Right side set of tracks foward and reverse motion

TXChannel 3 Left side set of tracks foward and reverse motion

TXChannel 4 Hook lift and lower. with the lift having an upper limit switch. to stop the lift at it’s highest point.

Mod 2 = Auto behavior
Will monitor multiple limit switches within the machine to be used as an auto balance mechinism.

This mod will have:
3 Motors
3 Line followers ( aka 1 set ) (possibility)
3 Optical shaft encoders (OSE)
10 limit switches

As unit starts to tip foward front limit switch is activated, tiggering a sub-rutine that will use the arms first to correct the off balance condition. If changing the lifting arm positions does not change the condition then it will activate a second sub-rutine that will adjust the counter weight to correct condition.

When the unit is first turned on it will go into a diagnostic mode which will activate all motors and put them into a limit switch then relying on the OSE will determine position in relation to each other.

**Tricky part **
When any of the sub-rutines are triggered then there needs to be a comm link between the two mods that puts mod 1 into “dead mode” where it does not work till the rutine is finished. If the rutine fails to complete it’s mission after a said time it releases the “dead mode” where the user interface is limited to righting an unsafe condition.

Lifting something too heavy the bot trys to auto compensate and fails, thus releasing the controls to lower the lifting motor only.

I know that this will be intensive if not impossible to be able to do it all. I also understand that you will need diagrams to pictures to help you understand this. and I will stive to post them. Please know that I’m not looking for someone to do this for me. I have a friend in real life who is going to help me program it he’s able to program with many utilities. But What I’m looking for is a community effort. If you know something Or have encounterd a situation that might be benificial then please add it. I feel this might take a few months to get it right.

Eventually, If this does work out with semi auto behavior I would like to see it on a barge. Lifting sunken R/C Boats from the water.
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Its kind of hard to help you because without seeing where the sensors are and what functionl they serve it’s hard to visualize your situation you need some detailed pictures.

I am having a difficult problem with the word “mod” what are you using that word for? Are you having two control MODules or does mod stand for some sort of MODification?

Mod is meaning modules

Why two are two micro-controllers needed?
You have only listed 7 motors,
and it is not clear what the last three do,
1 for arm raise-lower, 1 for counterweight forward/back, 1 for ?
You have lots of sensors listed but they dont all have puposes listed
It is easier to have a computer aided user control to prevent tipover,
than to separate the features but require them to talk to each other.

1st gonna talk about alot of the questions i’m getting about how the tracks work.

There is 4 sets of tracks to make the foot print for weight distrubition.

Look at the foot print as 3 pictures. Left side, Right side and Complete.

The left side is 2 tracks powered by 1 single motor driving a Traxxas Differential. :slight_smile: TMaxx 3.3 i do believe they are.
The right side is an identical set up but with a flipped differential.
Put the two units together and you can have the left two tracks running in unison and the right 2 tracks running in unison as well. when you start to turn the 2 outer most tracks move much more faster than the 2 inner tracks. thus the reason for the differential. this allows for different speeds. the outside tracks and move faster than the inner ones and not put a bind on the motion system.


On the front and rear of this unit there will be 2 limit switches. to detect tilt.

The Lifting rig has 4 support towers one is fixed to the frame work and the other 3 are free floaters attacked to a hinge point on the frame. Adjusting the the 2 center support towers allows for better weight distrubution. it changes the fulcrums of the lift and has a large variable floating point.

This also has a counter weight track sustem on the rear of the frame to help with adding weight to a further point in the rear.


Limit switches will be use to keep the support towers from crashing into one another when the rutine starts to balance the vehicle. The machine will know wehre the towers are with optical shaft encoders and a start up reset of all the towers. i would like to make it wehre the plat form is rotatable 180 degrees but i’m a bit worried of all the cabling that will need ot be tie wraped and making sure that i have enough to allow for twisting.

Do you have a prototype (some real crane you are copying in Vex?)
I dont see how moving the floating support towers affects the fulcrum.
They are all in one vertical plane, right?
Do you have a force vector diagram to demonstrate?
How many degrees of freedom do you plan for the arm?
(cable updown, arm forwardback, rotate? or fixed to tracks)
Do you have a goal to design towards? ( such as being able to pick up a softball from 2’ away, or lift a HO scale semi onto a HO railroad car or pick up a bowling ball and drop it from a height of 6" onto your foot?

OK, your posts still do not clarify anything… It sounds simple enough, but I am still baffled as far as why you need 2 controller modules… And when you say TX ports you mean motor ports right?

Programming this will probably be pretty simple. Do you have EasyC and the programming module (orange box)? If you have started programming it, maybe post what you have and it will be easier to visualize what exactly needs to be accomplished.

I like your design. Very cool. I made one from the starter kit but it is just a tower with a stationary arm.

have also made a bot simular to deadblow from battle bots dont have pics.

Getting more metal and harware parts soon.

Wish I could help with problem.