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TNERA

Inscrit(e) (le) 01 nov. 2021
Déconnecté Dernière activité mars 25 2025 09:12
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Messages que j'ai postés

Dans le sujet : Au bistrot du coin ...

02 février 2025 - 11:09

Here is a Sidewalk Chalk Drawing Robot, direct from the American Suburbs.

 

the guy jokingly cites "Keeping up with the Joneses" as his motivation. I think you would understand :), essentially “faire comme les voisins” or “courir après le standing”. It is really about the how he designed the robot. ;)

 


Dans le sujet : Moteur à encodeur ou servomoteur continu ?

16 janvier 2025 - 11:19

What is the question? 

If you want a "smart wheel" yes you can have the wheel with the motor, encoders and motor driver...  

But using a DC motor with an encoder is not the only working solution...

  • You can also try "smart servomotors" that have 360° endless feature like the feetech I have, 
  • find some smart wheels (something like a smart servo with the wheel integrated ...)
  • brushless motors ...
  • Stepper or BLDC with and without external encoders ...

Each solutions have pros and cons ... price, weight, power, size, speed, torque, life time, complexity...

Thanks! Yes, my question is about experiences and other options out there for purposes of motor odometry. My goal is to build a platform to explore Localization and Mapping (SLAM). I am thinking more rugged outdoor locations requiring good torque, life time, power. I would tend away from servo motors and steppers, only because I sense that outdoors is not the best environment for that. Brushless with encoders might be interesting in this scenario. My base thoughts are DC Motor and Encoder. I have no experience with the encoders, that is part of my question.

 

Currently, I am considering 'recycling' roomba motors. These motors assemblies have an encoder contained on the motor/gearbox. I just need to decode the signals needed. For the motor driver, I will need to provide a new solution as the roomba driver is built into the roomba main board.  

 

Fichier joint  roomba_wheels_distant.png   255,39 Ko   11 téléchargement(s)

 

My interest is similar to @ppmd, so this is a great topic. And interesting to follow to learn more. For my project, my preference is to try to reuse these roomba motors if that is feasible, and save my money for the sensors (lidars!)


Dans le sujet : Moteur à encodeur ou servomoteur continu ?

14 janvier 2025 - 11:40

I recommend a motor with an encoder... 

 

I like this part of the question. For builders that would like to have the odometry or the start of precision positioning, what are good options for motors w/encoders.  or is it best to add the encoder on to any basic motor?

 

I guess the complete assembly for a wheel would have Motor, motor-driver, and encoder.  Thus logic required for pwm of the motor, and processing of the data from the encoder.

 

thoughts/experience?


Dans le sujet : Mon nouveau Quadrupède

13 janvier 2025 - 10:51

Hi @pmdd, I feel your frustration! You still had a very productive design run, the robot looks great!
 
It is really too bad about the servos failing like that. I am impressed with having the ability to repair some of them. That should help identify some of the failure modes.
 
One concern I have with quadruped design is having the complete load of the leg/robot on the servo motor directly. Do you think this could have reduced the lifecycle of the servos?  The trade off would require a pin or bearing that connected the load to the chassis, and have the servos act to lift/push the leg pieces. This would reduce some, but not all of the load that is present on the servo. Although, it does introduce a new friction and requires transferring some of the torque.  
 
This is of course all present in @oracid's designs.   :) maybe!  ;)

Dans le sujet : Mon nouveau Quadrupède

06 janvier 2025 - 09:32

Oui, c'est bien là, le problème.

 

Perso, j'essayerais bien, ça : 

 

Ah!  but THAT gait is easy to take down with Harpoon and Tow Cables!!    :laugh1:

 

The Tölt looks very interesting. I think you can do this by just advancing (making earlier) the movement sequence of the front legs from a trot/diagonal sequence.  It could be adjusted by just a couple of timesteps perhaps.  I think it would have to be a 'mid speed' gait, after the momentum of the robot is gained.

 

good luck!