Printing RepWalker Mutation RA04

[jmccartney]

(05-06-2014 12:31 AM)steamboat Wrote:  I am curious about your oppinion to the leg and it's axis. Here I have a concept of ZERO clearance between the 5 mm hole and the 5 mm axis. For me it is easy to take a 5.1 or 5.2 mm drill to make it a perfect bearing fit. But what about the "Tochscreeners". I have heard that most holes on the easy printer are to small? I could (should?) go here to 5.2 mm in the boss also...

The leg and its axis seem very close to being fine. I did some light sanding and they move pretty easily, I used a tad of white lithium grease to slick up the suface a bit also. I will probably do a better job when I am at home.

The real problem is with the tendons. They are not even close to fitting onto the axis. I will have to put them on when I get home as I don't have an assortment of drill bits with me at work..

I can't imagine that much efficiency will be lost if the holes on the tendons are not a "perfect" bearing fit..but you would know more about that than me.

[steamboat]

(05-06-2014 04:26 AM)jmccartney Wrote:  The leg and its axis seem very close to being fine...
The real problem is with the tendons. They are not even close to fitting onto the axis...

Thats funny because it should have the same diameter = 5.0 mm.
As I printed it yesterday there was no need for any rework.

Yes, I will make it both 5.1 mm this will higher the chance for an easy fit right after printing.

By the way - the brain fastener is a cracker. You can not plug in the USB cable AND move the legs. A new design is on the printer already.

[steamboat]

Finaly I assembled the new #20 brain fastener you will find it on myweb page




To start moving the legs I have written a quick and dirty programm - take it as a first trial and add your own brain...

// written by Rainer Radow 2014-05-04 for the RepWalker
// easy code without special features...
// based on "zoomkat 10-22-11 serial servo test"
// Powering a servo from the arduino usually *DOES NOT WORK* - so you need an extra energy source!

String readString;
#include <Servo.h>
Servo servo_left, servo_right; // create servo objects to control a servo

int serial_input_value;

// here you can set the necessary value in ms to control the movement of the legs and the Shellmo
// STOP Shellmo
const int stop_l = 1200; // different timings for zero position because of the different internal circuits of the servos
const int stop_r = 1250;

// run FORWARD
// to add or substrct 150 ms is a good start - you can fine-tune it later
const int forward_l = stop_l + 150; // because of the servo arrangement you have to turn the servos in different directions
const int forward_r = stop_r - 150; // think about it ;-)

const int half_forward_l = stop_l + 70; // because of the servo arrangement you have to turn the servos in different directions
const int half_forward_r = stop_r - 70; // think about it ;-)


// run backwards
const int backward_l = stop_l - 150; // run backwards
const int backward_r = stop_r + 150;

// make a right turn while moving in forward direction
const int right_turn_fw_l = stop_l + 150;
const int right_turn_fw_r = stop_r + 150;

// make a left turn while moving in forward direction
const int left_turn_fw_l = stop_l - 150;
const int left_turn_fw_r = stop_r - 150;

// ================================================================================​==========
// ================================================================================​==========

void setup() {
Serial.begin(9600); //switch on the serial communication
servo_left.writeMicroseconds(stop_l); // run forward
servo_right.writeMicroseconds(stop_r);

servo_left.attach(7); //the PWM pin for the left servo control
servo_right.attach(5); //the PWM pin for the right servo control

Serial.println("Shellmo-test-"); //print a hello to the serial monitor - if this is switched on in the Aruino Software.
}

// ================================================================================​==========
// ================================================================================​==========

void loop()
{
// only necesary for serial communication -------------------------------------------------------
while (Serial.available())
{
char c = Serial.read(); //gets one byte from serial buffer
readString += c; //makes the string readString
delay(2); //slow looping to allow buffer to fill with next character
}

if (readString.length() >0)
{
Serial.println(readString); //so you can see the captured string
serial_input_value = readString.toInt(); //convert readString into a number

switch(serial_input_value)
{
case 5:
// STOP
Serial.println("HALT - stehen bleiben!");
servo_left.writeMicroseconds(stop_l);
servo_right.writeMicroseconds(stop_r);
break;

case 8:
Serial.println("Lauf Voran!");
servo_left.writeMicroseconds(forward_l);
servo_right.writeMicroseconds(forward_r);
break;

case 2:
// go backwards
Serial.println("Zurueck");
servo_left.writeMicroseconds(backward_l);
servo_right.writeMicroseconds(backward_r);
break;
case 3:

break;
case 4:
// turn on the table left
Serial.println("Links!");
servo_left.writeMicroseconds(backward_l);
servo_right.writeMicroseconds(forward_r);
break;
case 7:
// turn vorward left
Serial.println("links voran");
servo_left.writeMicroseconds(half_forward_l);
servo_right.writeMicroseconds(forward_r);
break;
case 6:
// turn on the table right
Serial.println("Rechts!");
servo_left.writeMicroseconds(forward_l);
servo_right.writeMicroseconds(backward_r);
break;
case 9:
// turn vorward right
Serial.println("rechts voran");
servo_left.writeMicroseconds(forward_l);
servo_right.writeMicroseconds(half_forward_r);
break;
}
readString=""; //empty for next input
}
}

[jmccartney]

I have mine together now. Just waiting on servos. Everything seems great.

[steamboat]

I hacked 4 of my 6 new HK servos already. They are easy to hack. Will show this later.

[jmccartney]

   

[steamboat]

(05-07-2014 05:06 AM)jmccartney Wrote:  printed

Nice color changes!

I did the picture part of the servo hack.
Servo Hack - pictures
Will do the text tomorrow.

This is how it falls apart:

[steamboat]

Hello James and Sho

I would like to publish the RA04 files at thingiverse now. I have learned to change all M3 holes from Ø3 mm to Ø3.1mm and the hub holes from Ø5 mm to Ø5.1 mm.

Additional I will change the position of the screws for the servos in the #1 muscle torso. They have to go a little up. Correspondingly I have to move the M3 holes in #2 and #3 a little downward to align the servo axis with the big hole in #2 and #3. With this it will match the HK standard servo.

Anything else to change?

[jmccartney]

(05-08-2014 05:39 PM)steamboat Wrote:  I would like to publish the RA04 files at thingiverse now. I have learned to change all M3 holes from Ø3 mm to Ø3.1mm and the hub holes from Ø5 mm to Ø5.1 mm.

I think those changes would be the only I could think of. The rest goes together and prints as easily as you can expect. I mean its really really easy to make. Should be popular.

Are you going to publish the meshes or make people reverse engineer them

(     As you can see your meshes are very very clean and export/import from .stl very easily which I find rare) I am playing with platform Ideas to put on top of my repwalker and find it easier to match up dimensions if I have the chassis in sketchup as well..)

[steamboat]

(05-08-2014 11:21 PM)jmccartney Wrote:  Are you going to publish the meshes or make people reverse engineer them

I do not have any SketchUp files. But I thought about to give the main dimensions of the coupling points to make it easy to adapt things.