Martian Rover (Perseverance)

[wissamms]

Hi all,

I would like to present in this topic the ongoing development of the project I'm currently working on, a replica of Perseverance martian rover.

I have the chance to be working in a company that supplies electronics for space applications, and we developped and manufactured one of the cameras that goes on this rover. While discussing with my management following the launch of Perseverance this July, I submitted the idea to have a kind of miniature rover where we could place a real camera, and therefore display it in exhibitions. And I innocently mentionned it could be done with LEGO, and it was accepted :)

Therefore I had more or less 4-5 months and a budget of 1500 euros to do something like this :

The camera would be placed in the big white box on top of the mast (SUPERCAM, built by french labs with french agency support).

All details for the development can be found on french Techlug.fr topic

The idea is to have full motorisation of the rover:

6 motors for the wheels rotation

4 motors for external wheels orientation

2 motors for the tilt/rotation of SUPERCAM on the mast

4 motors for the robotic arm (to be confirmed)

Control is currently done through 4 Control+ Hubs.

 

The LIEBHERR seemed like a good idea to be used as parts supply (motors, controller, white panels, tracks), 2 boxes purchased, and the rest is coming from Bricklink.

 

All started with the definition of the wheels (12 cm diameter), which gave the final dimensions of the rover

 

And control of the rotation / orientation

This design was later modified to take into account the largeweight of this rover.

 

Fixing the wheels is done with this turntable, on top of a VOLVO wheel which gives the round shape:

Big work has been done on the chassis, to be able to hold the weight but at the same time allow the freedom of movement of all wheels and structure

And I'm currently at the below stage:

The mast box design is still to be improved. I'm currently waiting for some additionnal pieces, to work on the top of the rover, as well as the robotic arm. Alors replace the yellow bricks with black ones.

The control is done through SBRICK interface on a tablet, which allows to control multiple motors through one command (usefull when it needs to go straightforward) :)

Hopefully some new images will be posted soon!

 

Edited October 5, 2020 by wissamms
Title

[Glaysche]

This is amazing.  I'm excited to see this as it progresses.

[JintaiZ]

Excellent work so far! Looking forward to see the completed build!

[amorti]

Looking amazing!

I recommend to look into brickcontroller2 for controlling the model. You'll be able to manage all your hubs from one gamepad, which will make it even more impressive when you present the model.

Congratulations on your promotion ?

[chlego]

WOW, this is amazing! It's probably one of the biggest Technic creations I've seen!

[wissamms]

Thank you all. Concerning the controller, I checked BC2, but an iPad with a beautiful interface would look more "professional" on an exhibition I believe. 

[Jeroen Ottens]

Nice one, I especially like the wheels.

[shimon]

Great, very interesting wheel design. 

This thing must be heavy, how much does it weight? 

[Jurss]

Challenging buils by means of size.

Main structure looks good now, but what I would do different way. I would consider option to integrate those motors more in structure. On turning wheels I would try to use them as main strutture, so put vertically, also for middle wheels I would try to use them more like an extension of that swingarm, tip of it. Most probably, then those frames won't be needed there, and everything could be littlebit liter.

Now I don't like how they stick out. Also You could hide wires better.

Edited October 6, 2020 by Jurss

[wissamms]

7 hours ago, shimon said:

This thing must be heavy, how much does it weight? 

It is now around 6.5 Kg. I estimate 10 kg at the end, including the PC and the camera electronics.

 

2 hours ago, Jurss said:

Main structure looks good now, but what I would do different way. I would consider option to integrate those motors more in structure. On turning wheels I would try to use them as main strutture, so put vertically, also for middle wheels I would try to use them more like an extension of that swingarm, tip of it. Most probably, then those frames won't be needed there, and everything could be littlebit liter.

Now I don't like how they stick out. Also You could hide wires better.

Thank you for the contructive proposals.

The 4 motors for the direction of the outside wheels stick out on top of the wheels as the idea was to make them like the real one:

 

Concerning the 6 motors for the rotation of each wheel, I see two issues, if they had to be integrated into the chassis:

- For the outside wheels it would mean having the gears and mechanical links going through the turntable which allows the direction of the wheel, and down to the center, quite complex to make

- It was critical to make the chassis as small as possible, but still sturdy enough to hold 10 kg. Currently I have a dimension for the chassis of 3 x 4 studs. If the motor was to be placed as an extension, it would mean adding additionnal liftarms around it to keep it strong enough, therefore increasing the dimensions of the chassis even more.

I agree that for the internal wheels motor placement could be improved, myabe by placing them vertically, I'll check what I can do.

 

Concerning the wires for sure they will be hidden at the end :)

 

[wissamms]

On 10/6/2020 at 7:35 AM, Jurss said:

Challenging buils by means of size.

Main structure looks good now, but what I would do different way. I would consider option to integrate those motors more in structure. On turning wheels I would try to use them as main strutture, so put vertically, also for middle wheels I would try to use them more like an extension of that swingarm, tip of it. Most probably, then those frames won't be needed there, and everything could be littlebit liter.

Now I don't like how they stick out. Also You could hide wires better.

You were right, I tried to work on the motorisation and the structure on the middle wheels, and I would make it like this (left wheel on the below picture)

 

The driving motor is now embedded inside the structure

 

Indeed, much better than what I had done previsouly 

 

So I guess I'll rework all 6 wheels for the driving motors, and see what I can do with the direction motors also.

 

 

[wissamms]

Hi.

During last days I reviewed commpletely the wheels mechanisms, now the motors are integrated in the structure. The chassis is also lighter and sturdier

 

 

A Laptop is integrated in the box, for the image processing of the camera that will go on top

 

A simple interface under SBrick allows  to control the different functions, of course a background image will be added.

 

Finally, here is a video of the rover in action:

Back and forth, tilt/rotation of the camera head, and going left full speed!

Now I need to work on the robotic arm in the front, and improve the overall look on top of the box.

[wissamms]

Hi,

Following the different remarks and discussions, I have reworked a great deal of the rover, and this is the final version that was presented.

 

With robotic arm deployed (4 degrees of freedom):

Close-up on the wheel:

And the mast:

I hope you enjoy it!

Edited December 20, 2020 by wissamms

[Pattspatt]

Looks wonderful! Great job on this project, the finished product is very impressive. Is there any chance of a video for the final rover? 

[wissamms]

yes, will do one soon

[PanMati]

thats huge