Terrain robot specs recommendation

Using Arduino Motors, Mechanics, Power and CNC
1

Hi,

I've been trying to figure out the required and suitable parts for a terrain robot. But I don't know exactly what specs I should work on ?

Target terrain robot design like this one:

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The specs I'm thinking of:

  1. Metal chassis, with those precise edges so it can deal with wet situations.
  2. DC motors to left the whole robot + any future load, a normal load; like, 2-4kg.
  3. What DC motor drivers I should buy; I have the ln298, is it enough ?
  4. Processor: I think any processor should do unless I'm dealing with a video stream, then at that point I need a fast one like ESP32.
  5. What other things I should consider ?
2

nice try Boston Dynamics.

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3

Sensors, size, spacing and frequency of bumps and holes, obstacles, steepness of slopes, weight to be carried, surface traction, sand and dirt getting into the gears and other moving parts, battery life, means of communication with base station, navigation, etc.

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4

Since you know the radius of those wheels and the approximate weight of the thing, you can compute the torque needed to move the thing on level terrain. Divide the needed torque by the number of powered wheels.

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5

They called me to do projects for them but I told them I'm really busy.

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6

I'll try to answer these as much as I can:

size
Not a huge one, max 40cm x 30cm or 30cm x 30cm

spacing and frequency of bumps and holes
sand and dirt getting into the gears and other moving parts
This is am important issue, so I should have some holes for ventilation.
But what if I want it to be like those terrain off road robots which can handle rough situations; like, water, sand ... etc.

If the whole body has no ventilation, then how to cool the internal parts ?

obstacles
The terrain design should be enough for me to run off-road; like, sand areas, some rocks ... etc.

steepness of slopes
surface traction
I don't know what this means ?

weight to be carried
Let's say 5-10kg. That's why I know that I need strong motors.

battery life
I'm thinking of using 8s li-ion to get 28V and use 24V motors.

I read that 24V is better than 12V motors.

means of communication with base station
I'm thinking of using long range rc receivers.

navigation

  1. Using a camera connected to android stream with vtx
  2. Using GPS module
7

Metal body parts are natural heat sinks!

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8

Have you not noticed that it takes more energy to drive or ride a bike up a steep hill, especially on a sandy slope?

Good introduction to robot vehicle engineering: https://www.societyofrobots.com/

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9

OK, what about the motors ? won't they heat too ?

or the kind of DC motors that have cooling fan attached from the factory. Like this one:

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will this work inside a closed chassis ?

10

Hello wolfrose

Have you ever thought about using stepper motors?
You can control each individual motor with its own direction of rotation and speed.
This will increase the manoeuvrability of the robot.

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11

What about current consumption ? I care about current draw because I want to run it for long range.

12

Of course it will! Your mounting frame becomes the heat path to the robot metal. Study up on heat and how to conduct heat!

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13

Yes, I know that metal is a thermal conductor and used for heat dissipation.

But shouldn't there any type of ventilation for the internal parts ?

14

Only if you overload them. Surely you have data sheets for your components that provide the temperature limits for them.

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15

OK, temperature issue should be for experimenting. The design shouldn't be a flaw-proof.

If I encountered temperature issue, then I will do some ventilation and mount a cooling fan.

Now the important part is how to design the chassis ?
I don't want to buy one of those metal chassis, they are very expensive.

I'm thinking of buying aluminum sheets and cut them according to the design I'm planning to.

Is there any guides of tutorials about working on a metal chassis ?

16

What are you looking for a monocoque where the body is the frame or are you looking for a metal frame with an attached body?

Metal sheet is only strong when it has curves and bends, not cuts. Look at your automobile body. How many flat sheets of material do you see?

May I suggest a metal frame and a fiberglass body?

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17

Yes, of course. But tell me how because I have no idea what exact design you mean ?

I've watched videos about these types of robots and I really liked them. They are robust and work well in off-road situations.

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If you noticed these types of robots have the chassis in parts and installed together with screws.

Like the one in the picture, I'm thinking that it has a steel body and powerful motors to move the whole weight of the robot.

18

OK, now I got what you mean by this type.

Yes, I want a metal frame with attached body.

19

This one is for $3000 ! Too expensive for me.

https://www.superdroidrobots.com/store/robotic-kits-platforms/wheeled-robots/product=3283

It's exactly what I want but it's too expensive for me.

20

Then you need to take the time to learn HOW to build things rather than wishing them into existence. Have you ever built anything? That is not a criticism, just wondering where you are coming from wanting a terrain robot, but not willing to pay for one.