3DOF homemade

Hi everyone !
I want to share with you guys our 3 DOF build.
I say "our" but, it's made by my stepdad for us.
Start for scratch, I bought everything we needed and we searched on the net everything.

Motors bought on alibaba 3x 350W 50rpm, some 3D print things on Simukit etc...
All the structure is made by aluminium (don't know the english word for these bars) oh, i'm French btw.

I could post some photos but there are a plenty of them, i have a google photo link with all the process from start to where we are now(almost finish).

https://photos.google.com/share/AF1...&key=WE1FMTM2NTdMYUhyaC1RWkpRdktLdHJ3T0l6R0d3

I'll receive the 3 screens this week, for the wheel/pedals I keep for the moment my G920, and I have a handbrake and shifter Fanatec. (support needs to be made).

I keep this thread update as soon as I receive the screens, the installation and the first test in game (the motors are already test and everything is OK).

Thanks again to my stepdad "The boss" I call him.

hope you'll like it, and i'm aware to any suggestion

Clem

That is an impressive, professional looking build! Nice to have a mill for making parts.

Thank you Cgodwin !

Here they are, not the best on the market but: 2K, 165HZ, VA, just what I need.
I chose 32" because I think that's better for the immersion...

We've made a custom aluminium support on wheels.
I receive the Shifter, first test should be on monday... fingers crossed !

So... not going qo well of course lol.
Everything is moving, but it's like the motors don't have enough strength.
Without the seat etc, we can stop the motor by hand .
Motors 350W 50rpm, sabertooth 2x32 (x2), we can mesure only 4v on the sabertooth where motors are.
Alimentation is 1200W 24v 50amp
Where can i adjust the strength of the motors?

I'm using the arduino micro.
Here is my setting in simtools:


In Describe I configured each sabertooth like this:

for the code arduino:

Spoiler

/*
* Original source code from sirnoname : x-sim.de
changelog:
1.6
- changing var for array of (int) values

1.5 (to do in this sketch) :
- add a switch to reset position of motors
1.4 :
- you can use a potentiometer to modify the global power of the motion simulator
- to disable this functionnality you need to set GP_select = 0;

1.23 :
- When serial send XE00C, the motion plateform will be placed in original position
- Use of packet serial communication instead of simplified serial (more stable)


10 bits (16 bits value / 64)
57600 bauds 8N1

Simtools : X1<Axis1a>CX2<Axis2a>CX3<Axis3a>CX4<Axis4a>CX5<Axis5a>CX6<Axis6a>C

XE00C - End
Pin out of arduino for Sabertooth

Pin 2 - TX data to connect to S1 Sabertooth 1
Pin 3 - TX data to connect to S1 Sabertooth 2
Pin 4 - TX data to connect to S1 Sabertooth 3

Analog Pins

Pin A0 - input of feedback positioning from motor 1
Pin A1 - input of feedback positioning from motor 2
Pin A2 - input of feedback positioning from motor 3
Pin A3 - input of feedback positioning from motor 4
Pin A4 - input of feedback positioning from motor 5
Pin A5 - input of feedback positioning from motor 6

Pin A11 - input of potentiometer to define the global power

Pin 11 - switch to move the motion simulator in standby value. connect to GND

As well 5v and GND pins tapped in to feed feedback pots too.
*/

#include <Sabertooth.h>
#include <SoftwareSerial.h>

//Some speed test switches for testers
#define FASTADC 1 //Hack to speed up the arduino analogue read function, comment out with // to disable this hack

// defines for setting and clearing register bits
#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif
#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

#define LOWBYTE(v) ((unsigned char) (v)) //Read
#define HIGHBYTE(v) ((unsigned char) (((unsigned int) (v)) >> 8))
#define BYTELOW(v) (*(((unsigned char *) (&v) + 1))) //Write
#define BYTEHIGH(v) (*((unsigned char *) (&v)))

int DeadZone = 9; //increase this value to reduce vibrations of motors
int ReadAnalog = 6;

int EmergencyPin = 11; // Emergency switch (GND)

//motors array : Pin, currentAnalog, target, Minpot, MaxPot, pot deadzone, standby value, P, I, D, integrated error, last error, Power
int motors[6][13] = { {A0, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}, //motor 1
{A1, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}, //motor 2
{A2, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}, //motor 3
{A3, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}, //motor 4
{A4, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}, //motor 5
{A5, 0, 0, 62, 962, 0, 512, 100, 0, 100, 0, 0, 0}}; //motor 6

int GlobalPowerPin = 12; //use a potentiometer to define the power of the motion simulator on pin A11 (12)
int GP_select = 0; //1:use potentiometer 0:always 100%
double GlobalPower = 1.00; //100%

int buffer=0;
int buffercount=-1;
int commandbuffer[5]={0};

int disable = 1; //Motor stop flag

SoftwareSerial SWSerial1(NOT_A_PIN, 2); //Pin 2 utilisé pour communiquer avec la Sabertooth
SoftwareSerial SWSerial2(NOT_A_PIN, 3); //Pin 3 utilisé pour communiquer avec la Sabertooth
SoftwareSerial SWSerial3(NOT_A_PIN, 4); //Pin 3 utilisé pour communiquer avec la Sabertooth
Sabertooth ST1(128, SWSerial1); //nom de l'objet communication serie avec une pin differente de TX
Sabertooth ST2(128, SWSerial2); //nom de l'objet communication serie avec une pin differente de TX
Sabertooth ST3(128, SWSerial3); //nom de l'objet communication serie avec une pin differente de TX

void setup()
{
Serial.begin(57600);

SWSerial1.begin(115200); //boutons 1 et 2 OFF
SWSerial2.begin(115200); //boutons 1 et 2 OFF
SWSerial3.begin(115200); //boutons 1 et 2 OFF

ST_stop();

disable=1;

pinMode(EmergencyPin, INPUT_PULLUP);


#if FASTADC
// set analogue prescale to 16
sbi(ADCSRA,ADPS2) ;
cbi(ADCSRA,ADPS1) ;
cbi(ADCSRA,ADPS0) ;
#endif
}

void ST_stop()
{
ST1.motor(1, 0);
ST1.motor(2, 0);
ST2.motor(1, 0);
ST2.motor(2, 0);
ST3.motor(1, 0);
ST3.motor(2, 0);

ST1.stop();
ST2.stop();
ST3.stop();
}

void FeedbackPotWorker()
{
for(int z=0;z<6;z++)
{
motors[z][1]=0; //set to 0 all current analog
}

for(int i=0;i<ReadAnalog;i++)
{
for(int z=0;z<6;z++)
{
motors[z][1] += analogRead(motors[z][0]);
}
}

for(int z=0;z<6;z++)
{
motors[z][1] /= ReadAnalog;
}
}

void SerialWorker()
{
while(Serial.available())
{
if(buffercount==-1)
{
buffer = Serial.read();
if(buffer != 'X')
{
buffercount=-1;
}
else
{
buffercount=0;
}
}
else
{
buffer = Serial.read();
commandbuffer[buffercount]=buffer;
buffercount++;
if(buffercount > 3)
{
if(commandbuffer[3]=='C')
{
ParseCommand();
}
buffercount=-1;
}
}
}
}

void ParseCommand()
{
int diff;
int i;
bool commande = false;

switch (commandbuffer[0])
{
case '1':
i = 0;
commande = true;
break;

case '2':
i = 1;
commande = true;
break;

case '3':
i = 2;
commande = true;
break;

case '4':
i = 3;
commande = true;
break;

case '5':
i = 4;
commande = true;
break;

case '6':
i = 5;
commande = true;
break;

case 'E':
commande = false;
unsigned long start;
unsigned long time;
start=millis();

for(int z=0;z<6;z++)
{
motors[z][2]=motors[z][6]; //reset to standby position
}

time = millis();

while(time < (start + 1500)) //1.5s
{
FeedbackPotWorker();
CalculatePID();
SetPWM();
time=millis();
}

ST_stop();

disable=1;
break;

default:
commande = false;
return;
break;
}

if (commande)
{
commande = false;
motors[2]=(commandbuffer[1]*256)+commandbuffer[2]; //target
diff = constrain((GlobalPower * (motors[2] - 512)), -511, 511) + 512;
motors[2]=map(diff,0,1023,motors[3],motors[4]); //ajustement en fonction des min et max
disable=0;
}
}

int updateMotorPid(int targetPosition, int currentPosition, int numMot)
{
float error = (float)targetPosition - (float)currentPosition;
motors[numMot][10] += error;
motors[numMot][11] = error;
float pTerm_motor = ((float)motors[numMot][7] * error) / 100.0;
float iTerm_motor = ((float)motors[numMot][8] * constrain(motors[numMot][10], -100, 100)) / 100.0;
float dTerm_motor = ((float)motors[numMot][9] * (error - motors[numMot][11])) / 100.0;

return constrain((pTerm_motor + iTerm_motor + dTerm_motor)/2, -127, 127);
}

void CalculatePID()
{
for (int z=0;z<6;z++)
{
motors[z][12] = updateMotorPid(motors[z][2],motors[z][1], z);
}
}

void SetPWM()
{
for(int z=0;z<6;z++)
{
if (abs(motors[z][2] - motors[z][1]) <= (DeadZone + motors[z][5]))
{
motors[z][12] = 0;
}
}

ST1.motor(1, motors[0][12]);
ST1.motor(2, motors[1][12]);
ST2.motor(1, motors[2][12]);
ST2.motor(2, motors[3][12]);
ST3.motor(1, motors[4][12]);
ST3.motor(2, motors[5][12]);
}

void loop()
{
//Program loop
while (1==1) //Important hack: Use this own real time loop code without arduino framework delays
{
FeedbackPotWorker();
if (GP_select == 1)
{
GlobalPower = double(analogRead(GlobalPowerPin)) / 512.0 ;
}
else GlobalPower = 1.00;

if (digitalRead(EmergencyPin) == LOW)
{
for (int z=0;z<6;z++)
{
motors[z][2] = motors[z][6]; //target = stdby
}
}

else SerialWorker();

CalculatePID();
if(disable==0 || digitalRead(EmergencyPin) == LOW)
{
SetPWM();
}
}
}

Hello,

First of all, nice setup you got there! Props to you!

On second hand, do you have a connection schematic of your motors? Maybe that will help us to find out where is your lack of motor power coming from.

Greetins.

Hope it will help

Yes Arduino micro.
I post the code i'm using just above, in the spoiler.

The motion rig is finally ok !
I put an other code in the arduino, and now motors have strengh and energy.

The last thing is that the 2nd motor on the sabertooth is less powerfull...
Do you have an idea? I have now 18V on each motor on the sabertooth BTW.

Hi everyone,

My setup is finally done...