[MOC] Telescopic Crawler Crane (with Automated Distribution Gearbox)

[JLiu15]

Motorized model of a crawler crane with Mindstorms EV3. Features driven tracks, and superstructure functions controlled by an automated distribution gearbox.

Functions/features:

• Driven tracks
• Boom elevation
• Boom extension
• Winch
• Superstructure rotation

Ever since TLG released the rotary catch pieces from the Bugatti set I sought to incorporate it in a distribution gearbox so that I could control 4 functions with 2 motors. However, I did not want the play experience to be constantly interrupted by shifting the gearbox. For instance, if I used PF and installed a stepper mechanism to control the gearbox, I'd constantly have to count how many "shifts" I've done to ensure the right function is engaged. With that in mind, I realized Mindstorms EV3 is the perfect solution to this - by simply utilizing a touch sensor, the mechanism can detect how far the shifting motor has rotated thus automatically selecting the right function.

The gearbox, which sits at the heart of the superstructure, features a cam attached to the shifting motor to hit a touch sensor. When a command is received from the remote, the shifting motor rotates until the touch sensor is pressed, then the EV3 tells the shifting motor to rotate a certain number of degrees to select the corresponding function. This utilizes a switch/case for the remote, and because it features up to 11 button combinations all superstructure functions are controlled from the same channel (channel 2 on the remote). This gives controlling the model a very natural feel, and sometimes I even forgot that I was controlling a distribution gearbox because the EV3 shifts it so seamlessly.

As for driving, it too uses a switch/case for the remote. Because it's just a simple tank drive, the commands for this are much more straightforward compared to the gearbox functions. Driving is controlled from channel 1 on the remote. Additionally, there are sound effects that play while operating the crane. Pressing the left two buttons together in the 1st channel starts the engine (thus starting the program), and pressing the right two together stops it (thus ending the program). Because the PF IR remote uses levers instead of buttons, this effectively makes the model inoperable with only a PF remote. The EV3 remote feels more natural for controlling this model too, as some superstructure functions (boom elevation and superstructure rotation) involves pressing two buttons simultaneously.

In the end, I'm pretty satisfied with how this model turned out. I was initially worried that this gearbox I had in mind won't work as smoothly as I imagined, but it turned out to work flawlessly. It often made me forget that I was even controlling a gearbox as the EV3 does the shifting for me. Of course, there's still areas that could be improved - for instance, the boom extension and winch operate pretty slowly. Not using a worm gear in those mechanisms probably would've helped, but that would mean the mechanism becomes "unlocked" as soon as the gearbox disengages it. Occasionally the gearbox would jam, making me restart the program, but overall the finished model met my expectations.

Video:

Photos:

 

 

 

 

 

 

 

Edited July 12, 2020 by JLiu15

[JLiu15]

Here is the program for the MOC.

Main Program:

Drive My Block:

Gearbox My Block:

Edited January 28, 2022 by JLiu15

[suffocation]

This is brilliant!

I know bugger-all about Mindstorms and programming  in general so I was wondering - would your idea also work for an eight-way distribution gearbox? Something like this:

More pics here: https://bricksafe.com/pages/hateofallhatreds/mocs/12.-cherry-picker/wip

[JLiu15]

31 minutes ago, suffocation said:

This is brilliant!

I know bugger-all about Mindstorms and programming  in general so I was wondering - would your idea also work for an eight-way distribution gearbox? Something like this:

More pics here: https://bricksafe.com/pages/hateofallhatreds/mocs/12.-cherry-picker/wip

I believe it should work in theory.

How many degrees does the shifting input have to rotate per gear? Just wondering since it's an eight-way and I'm assuming a full rotation goes through all the outputs. But regardless, you could still use the same principle - a lever attached to the shifting motor presses a touch sensor on one of the outputs, and for the other ones just program it to turn a certain number of degrees after hitting the touch sensor.

Also that gearbox looks nice and complex - do you have a video of the MOC you used it in?

[Parazels]

Very interesting!

I do love models with a gearbox and I'm glad you found a way, how to make the gearbox extremely efficient!

[suffocation]

15 hours ago, JLiu15 said:

I believe it should work in theory.

How many degrees does the shifting input have to rotate per gear? Just wondering since it's an eight-way and I'm assuming a full rotation goes through all the outputs. But regardless, you could still use the same principle - a lever attached to the shifting motor presses a touch sensor on one of the outputs, and for the other ones just program it to turn a certain number of degrees after hitting the touch sensor.

Also that gearbox looks nice and complex - do you have a video of the MOC you used it in?

The shifter rotates 90° at a time, so the orange wave selector engages two of the four driving rings around it, enabling two functions at a time.

There's an absolute rubbish video here (I recommend muting and playing at 2x ).

[JLiu15]

32 minutes ago, suffocation said:

The shifter rotates 90° at a time, so the orange wave selector engages two of the four driving rings around it, enabling two functions at a time.

There's an absolute rubbish video here (I recommend muting and playing at 2x ).

Okay, so considering it rotates 90 degrees at a time my setup in this MOC is perfect for you then - you can take a look at the Gearbox My Block to get a general idea on how it’s done. 

15 hours ago, Parazels said:

Very interesting!

I do love models with a gearbox and I'm glad you found a way, how to make the gearbox extremely efficient!

Thanks! I’m glad you like it :)

[suffocation]

10 minutes ago, JLiu15 said:

Okay, so considering it rotates 90 degrees at a time my setup in this MOC is perfect for you then - you can take a look at the Gearbox My Block to get a general idea on how it’s done. 

Cheers mate, thanks!

[JLiu15]

2 hours ago, suffocation said:

Cheers mate, thanks!

No problem! :)