Let's Make Robots!

MDi #2

Will run around autonomously and remote controlled

     UPDATE - September 23, 2013

 

     Hallo Leute!

     What's new on this update? Apparently, nothing! :)

     In the case of the mechanical part and body building it's actually nothing new... The body construction at this time should be done, and next days will be the robot competition that I've mentioned before... But robot won't be ready for it...

     Ok, no problem... The delay on the construction occurred because I wanting to give to this robot a "big brain", and inside it will work MyRobotLab. Ya, I have tried something with this amazing software some time ago, but since I don't have many skills with Python, I've ended up abandoning it for some months... But now I'm working with this software again... And thanks to some Python studying and specially the great help from MRL guys (GroG and Alessandruino), this project is evolving.

     Now I'm controlling the robot with a XBox 360 joystick. And it works this way: Arduino Mega2560 is attached to my laptop. Laptop runs MyRobotLab which receives the commands from joystick and send to Arduino (via serial communication) the correspondent movements for each button (or combo).

     Some examples of movements:

  • Left stick Y axis: forward and backward;
  • Left stick Y axis: turn left and right;
  • RB + directional pad: controls shoulder joints;
  • RT + directional pad: controls elbow joint;
  • RB or RT + A / B: close and open hand
  • Y + directional pad: controls the head;
  • Start button: plays a audio file that says: "Hello all you guys."
  • Back button: plays a audio file that says: "Hello World from Teutonia." ..... note: Teutonia is my hometown! :)
  • And so......

 

 

     MyRobotLab simply don't have limits! For example: it can make your robot say things :), can run Sphinx, OpenCV, and many many other services... Ya, right, it needs a PC and, as you can see on my new video, it uses a USB cable to communicate with Arduino... Well, the answer for this can be inside of this box....

 

 

 

     UPDATE - August 10, 2013

 

     Hi guys. I've passed few days thinking about the design of a piece to interconnet the torso with the main chassis. And have changed my mind a few times. But I managed to get a model that I liked. So, the things begin to evolve! 

     Yes, I know that it's seeming more and more like Johnny 5. But at this moment I can't imagine a better design for an interactive robot.

     This week was good also because I've received 3 servos (HS-81), which will be used in the hands and in the head tilt.

 

     Below you see the construction of the "interconnect" piece, and other things like the arm and torso assembled.

 

 

 

 

     This long piece is a Lynxmotion femur clone.

 

     Torso assembling...

 

 

     That's all for now. Next week I'll got to make some break in the work because I'll be in vacancy and will travel to Germany and France with my wife. :) When I'll get back to Brazil I intend to work hard in this project to show it in a kids Lego robotics competition (to inspire the kids) in September.

     See you guys!

     Bis später!

     Au revoir!

 

 

 

     UPDATE - July 6, 2013

 

     Got some progress this week on my new project. Many hours of working...

     Now is done the main chassis and the tracks.

     Below you see the assembling.

 

     As you can see, the chassis houses too the batteries holder (will be two holders later).

 

     The Vex kit uses squared axles, and as my DC geared motors have D type axle, I have to make some adaptations on the sprocket and attach an aluminium hub.

 

     Attaching the motors, idle wheels and sprockets.

 

     Just to see the size... around 11".

 

     This mechanism will be used for the torso inclination. The shock absorbers are more for esthetic than absortion.

 

 

     To continue the project I need to order more polystyrene sheets... I've utilized all that I have at home.

     Need to order also other parts, like 3 servos (HS-81), one more battery holder and batteries, more nylon standoffs and screws.

     Later I'll make a review on this page to standardize the size of the pics.

     Well, I'm satisfied with the progress till now.

 

 

 

     FIRST POST - June 29, 2013

 

     It's a bit early to start a post for this, since just a little bit of work is done, but I would like to show you the new project which I'm working on.

     This is a sequence of my previous project (MDi-eins), but with some more new features, mainly for its 2 DOFs head with led matrix for facial expressions and environment interaction.

     The arms continues on the same way: 4 DOFs with a functional hand. The locomotion method will be tank treads with DC geared motors.

     The great diference in this project is the design of the torso. A piece (130mm lenght) of 75mm PVC pipe is the main of the torso construction. In the back is a "bag" for the electronics and an Arduino Mega2560 (my latest purchase).

 

     This is the layout that involves the PVC pipe to determine the cuts.

 

     Below some progress of the torso construction.

 

 

 

     On the back of the electronics bag will be attached the PS2 wireless controller receiver.

 

 

     Below you see the construction of my preferred part (the tracks brackets).

     Just glued the layout on the polystyrene sheet and cut it with sharp blade.

 

 

     As this part is a bit long, needed to be more thick. So I made it with 3 layers (3x 2mm sheet = 6mm thick). And to save some material I made the middle layer only with polystyrene patches.

 

 

     One more of my recently purchases (Vex tank tread kit).

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I finally posted some photos of the my Vex tread mechanism.

It's still in prototype form but you can see what the expanded PVC looks like. Besides the 3mm stuff, I also plan to use 6mm material for the motor mount and other places where I need the stucture to be extra rigid.

New work on the treads...

Hi Dickel

This is an awesome robot! The time spend sorting out the mechanics has definitely paid dividends and now you are controlling it effortlyless with some preety powerful hardware. I'm very interested to see where this goes.

I find you construction technique very interesting. Do you find polstyrene a strong enough for purpose? It obviously works well but when you lift an object with thr robot arm, is the strength limited by the servo's rather than than the arm itself?

Clive

Hi Clive! Thank you very much! 

Surely I'll have to do some improvements in many parts (mechanicals) of this project. I think the polystyrene is strong enough for whatever you want to do with it, but must be used with the right thickness. For example, for the long tracks bracket I'm using just 6mm thick (3 layers of 2mm combined), and it's not enough, because when the robot passes over some object, the bracket bends a bit. For this part I think will need 10 mm thick, or a horizontal reinforcing bar, along all the part.

For the long part of the body inclination (Lynxmotion femur clone), something similar occurrs (it's now just 4mm thick), and I think for this part I'll need 6mm thick. Also, will need to change the servo (currently using a HS-645MG, and I'm searching for a stronger alternative).

About the question of lifting object, stronger servos will do the work without any problems. But this part of the project don't concerns me now, and I think it's working pretty well if you consider that I'm using only micro and mini servos. For example, for the shoulder pitch servo I'm using a Hitec HS-5245MG (his torque is about 4.4kgf/cm @ 4.8V). For the shoulder yaw servo I'm using a Hitec HS-225MG (his torque is about 3.9kgf/cm @ 4.8V). For the elbow servo I'm using a Hitec HS-82MG (his torque is about 2.8kgf/cm @ 4.8V). But I have plans to upgrade some servos... 

For the torso rotation don't need a much stronger servo, because the weight of the torso will be counterbalanced when the robot will have their two arms. :)   ..... But aditionally I've ordered this piece (below picture, Load Bearing Servo Block for Hitec standard servos)...

... and it will prevent (if some overloading happens) the damage of the output shaft of the servo. Would be nice to have it also on the two arms shoulder pitch.

But resuming... I think the polystyrene is a strong material, however must be used with the right thickness... Greater the lenght of piece is, thicker must be. And for the servo brackets that I've custom made, 4mm thick is strong enough.

Mech-Dickel

Thanks for the very detailed reply!  I must say your robot looks very professional, and you seem to have a good handle on build strength. I'm keen to give your building techniques a try sometime as I've not really worked with much else than wood and metal in the past.

Good to learn some new skills :-)

Watching to see your progress !

Thank you one more time for your nice comment! If you want to try something with polystyrene or PVC with the method that I use, take a look at this tutorial http://letsmakerobots.com/node/32828 . It's not so much documented, but can help you a bit.

Mech-Dickel

hello dickel

nice job i always happy to see you advance about your robot

thank you for show is your bouild

do you think give us your plans for build it the same?

ambroise

Hi ambroise! Thanks man!

Actually I'm planning to turn it into a totally open source project. When the things are more evolved, I intend to share all the templates for the parts, circuits, scripts.... well, everything! ..... to anyone interested can make their own.

This is something that I'm adding to my project http://www.youtube.com/watch?v=nWxVrGpNhKk .

I like what you are doing!

I'm working on a robot using an rpi as brain! and as i see you will use an rpi. you can use the arduino with firmata and node js (the framework jhonny five) it's very simple!

Good luck for your robot!