Self balancing robot

New code for the motor part of the X-bot

Posted in Arduino, Processing, Self balancing robot on April 22nd, 2011 by x-firm – Comments Off

I have recoded the motor part and added the encoder for the other motor and made a PID for each motor that takes the output from the current PID. This for trying to get the two motors to behave equal. The original PID is only looking on the right motor encoder as before. But I’m calculating the current speed in pulses/10ms for each motor and then using that and the output from the old PID to control the motors for a requested speed in pulses/10ms..

That feels better than just sending a value of 0-255 that has no connection to the speed of the motor that are depending on the surface and battery level.

I have made a new sketch for the bot and a GUI to make settings and testing the motor PIDs you can download it from this links:
Motor_PID_Enc_v2 (Bot code)
Motor_PID_Enc_v2 (GUI)

Nice balancing bot controlled by a WiiMote

Posted in Arduino, Self balancing robot on April 6th, 2011 by x-firm – Comments Off

Found a nice robot that was built and programed using parts of the Balancing Robot For Dummies guide. A nice looking bot..

The most interesting is that he has the WiiMote connected directly to the Arduino true a USB HID shield.. Instead of having both the bot and the WiiMote connected to a computer that acts as a gateway..

More information here..

My first attempt for Fuzzy Logics

Posted in Processing, Self balancing robot on February 2nd, 2011 by x-firm – Be the first to comment

I have now successfully created a fuzzy logic controller using Processing.

My test case was getting an object avoiding obstacles when given order to move to specific target..

You can try it here

The input variables was simple angle and distance.

Fuzzy sets for inputs:

Angel to obstacle:
smallAngle
mediumAngle
largeAngle

Distance to obstacle:
smallDist
mediumDist
largeDist

Instead of using linguistic rules I used something called FAMM(Fuzzy associative memory matrix) and that only work in a 2 input, 1 output scenario.

smallAngle mediumAngle largeAngle
smallDist 90° 55° 35°
mediumDist 55° 35° 25°
largeDist 35° 25° 5°

Then defuzzification is done true weighting the relationships in the FAMM..

I will improve some parameters of the controller and optimize it a little before I try It on my balancing robot..

X-Bot v2

Posted in Self balancing robot on December 23rd, 2010 by x-firm – Be the first to comment

I have now started on a second version of my balancing bot do the first one was a little to heavy in my opinion. I will remove the breadbord from the robot and make everything more permanent installed on the bot.

I’m tired of being needed to unhook the batteries every time I just want to turn of the motor power..

So now there will be one switch for the logic and motor power and also a fuse on the motor power.

I have started with the body parts of the robot like you can see in the pictures below.

Middle plate

Bottom plate

Calibrating/testing the motors and encoders..

Posted in Arduino, Processing, Self balancing robot on November 24th, 2010 by x-firm – Be the first to comment

I started to check the differences of the motors by using the encoders to try to see the distance the motors turned in a constant time and get a factor for the diff. I drive the motors in both directions in four different speeds 50, 100, 200, 250..

I made a sketch for the Arduino and a GUI sketch in processing based on the Balancing Bot GUI, and thought that this cant be so hard to do just see the diff. and calculate a factor for the faster motor but that was not the case..

The first run gave me the results like in the image below, where the motors behaved very different in forward to backward motion. When going forward for a time constant(2000ms) and then sending the drive_motor(0) the motor continued running in free spin for a short while. But when running backward the motor brakes for a short while.

Click for larger image

Speed   L           R

255    7662   :  7413

-255   -5516  :  -5541

150    6582   :  6386

-150   -4901  :  -4872

50     3342     :  3291

-50    -2747   :  -2705

As you can see the behavior is very different in the two directions..

I changed the drive_motor function like below and tried again and the result was better but is I going about this in the right way?

int Drive_Motor(int torque)  {
  if (torque > 0)  {
    // drive motors forward
    digitalWrite(InA_R, LOW);
    digitalWrite(InB_R, HIGH);
    digitalWrite(InA_L, LOW);
    digitalWrite(InB_L, HIGH);
    forward = true;
  }else if(torque < 0) {     // drive motors backward
    digitalWrite(InB_R, LOW);
    digitalWrite(InA_R, HIGH);
    digitalWrite(InB_L, LOW);
    digitalWrite(InA_L, HIGH);
    torque = abs(torque);
    forward = false;
  }else{
    if(forward){
      digitalWrite(InA_R, HIGH);
      digitalWrite(InB_R, LOW);
      digitalWrite(InA_L, HIGH);
      digitalWrite(InB_L, LOW);
    }else{
      digitalWrite(InA_R, LOW);
      digitalWrite(InB_R, HIGH);
      digitalWrite(InA_L, LOW);
      digitalWrite(InB_L, HIGH);
    }
  }
  //if(torque>5) map(torque,0,255,30,255);
    analogWrite(PWM_R,torque * motorOffsetR);
    analogWrite(PWM_L,torque * motorOffsetL);
    Serial.println(torque,DEC);
}

Now it looks like the Arduino and the motor controller is behaving in the same way in both directions. I need to take some more readings to see if the differences that are left are linear in some way.. It feels like there are a difference between the motors in both directions but also that both motors are going faster forward, and that I think is created by the motor control??..

See image below..

Click for larger image

Heres the Arduino sketch I used..

Heres the Processing sketch I used..

The main part of the Arduino sketch:

// KasBot Encoder test V1  -  Main module       basic version, angles in Quids, 10 bit ADC
/*
  Description:
  The KasBot Encoder test Vx is made for checking that the encoder signal workes and
  to tune the diffrenses from your motors..

  This code is aimed for the Encoder test GUI v1.0

  Version log:

  v1.0  -

*/

#define   InA_R          6                      // INA right motor pin
#define   InB_R          7                      // INB right motor pin
#define   PWM_R          10                     // PWM right motor pin
#define   InA_L          8                      // INA left motor pin
#define   InB_L          9                      // INB left motor pin
#define   PWM_L          11                     // PWM left motor pin
#define encodPinA_R      3                      // encoder A pin left motor
#define encodPinB_R      5                      // encoder B pin right motor
#define encodPinA_L      2                      // encoder A pin left motor
#define encodPinB_L      12                     // encoder B pin right motor

#define LOOPTIME         100                    // PID loop time
#define FORWARD          1                      // direction of rotation
#define BACKWARD         2                      // direction of rotation

#define DELAY_TIME       5000                   //Time to delay after motion
#define RUN_TIME         2000                   //Time to run motor

int speeds[] = {50, 100, 200, 255};
int speedIndex = 0;

int STD_LOOP_TIME  =  9;             

int lastLoopTime = STD_LOOP_TIME;
int lastLoopUsefulTime = STD_LOOP_TIME;
unsigned long loopStartTime = 0;

unsigned long delayStart = 0;

long count_R = 0;                                 // rotation counter right motor
long count_L = 0;                                 // rotation counter left motor

boolean frwMotion = true;                         // motor moves

void setup() {
  pinMode(InA_R, OUTPUT);
  pinMode(InB_R, OUTPUT);
  pinMode(PWM_R, OUTPUT);
  pinMode(InA_L, OUTPUT);
  pinMode(InB_L, OUTPUT);
  pinMode(PWM_L, OUTPUT);

  pinMode(encodPinA_R, INPUT);
  pinMode(encodPinB_R, INPUT);
  digitalWrite(encodPinA_R, HIGH);                      // turn on pullup resistor
  digitalWrite(encodPinB_R, HIGH);
  attachInterrupt(1, rencoder_R, FALLING);

  pinMode(encodPinA_L, INPUT);
  pinMode(encodPinB_L, INPUT);
  digitalWrite(encodPinA_L, HIGH);                      // turn on pullup resistor
  digitalWrite(encodPinB_L, HIGH);
  attachInterrupt(0, rencoder_L, FALLING);

  Serial.begin(19200);
}

void loop() {
// ********* Simple motor test for serial monitor ***********************

  //motorDebugForSerialMonitor();

// *********************** Motor drive **********************************
  //Turns motors on for RUN_TIME and then off for DELAY_TIME
  if((millis() - delayStart) <= RUN_TIME){
    if(frwMotion){
      Drive_Motor(speeds[speedIndex]);
    }else{
      Drive_Motor((speeds[speedIndex] * (-1)));
    }
  }else if((millis() - delayStart) > RUN_TIME){
    Drive_Motor(0);
  }

  if((millis() - delayStart) >= (RUN_TIME + DELAY_TIME)){
    delayStart = millis();
    if(frwMotion){
      frwMotion = false;
    }else{
      speedIndex++;
      frwMotion = true;
    }
    clearCounts();
    if(speedIndex >= 3) speedIndex=0;
  }

 // *********************** print Debug info *****************************
  serialIn_GUI();       //Processing information from a pc
  serialOut_GUI();	//Sending information to pc for debug

 // *********************** loop timing control **************************
  lastLoopUsefulTime = millis()-loopStartTime;
  if(lastLoopUsefulTime<STD_LOOP_TIME)         delay(STD_LOOP_TIME-lastLoopUsefulTime);
  lastLoopTime = millis() - loopStartTime;
  loopStartTime = millis();

}

void clearCounts(){
  count_L = 0;
  count_R = 0;
}

void motorDebugForSerialMonitor()
{
  Drive_Motor(255);
  delay(2000);
  Drive_Motor(0);
  delay(500);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  Drive_Motor(-255);
  delay(2000);
  Drive_Motor(0);
  delay(500);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  Drive_Motor(150);
  delay(2000);
  Drive_Motor(0);
  delay(500);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  Drive_Motor(-150);
  delay(2000);
  Drive_Motor(0);
  delay(500);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  Drive_Motor(50);
  delay(2000);
  Drive_Motor(0);
  delay(500);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  Drive_Motor(-50);
  delay(2000);
  Drive_Motor(0);
  delay(2000);
  Serial.print(count_L,DEC);
  Serial.print(" : ");
  Serial.println(count_R,DEC);
  clearCounts();
  delay(4500);

  while(true){delay(100);}
}

New version of the Balancing Bot GUI

Posted in Arduino, Processing, Self balancing robot on November 17th, 2010 by x-firm – Be the first to comment

New version of the bot code:

KasBotV1
KasBotV1.2_Serial (Use this one when using the Balancing Bot GUI)

New version of the GUI:

BalancingBotGUI v1.2

Currently you will see trends for the following values:
- ACC_X, _Y, GYR_Y
- actAngle, ACC_angle
- pTerm, iTerm, dTerm
- drive

You can also see and change the following values:
- setPoint
- K
- Kp
- Ki
- Kd

Now the hardware is mounted on the robot..

Posted in Self balancing robot on November 13th, 2010 by x-firm – Be the first to comment

I have now mounted the hardware on the robot, soon I can test run it…

I have added in the Balancing Bot GUI the possibility to change the PID parameters like in the image below:

When I have tested it some more I will post the sketch..


The start of the balancing bot…

Posted in Self balancing robot on November 10th, 2010 by x-firm – Be the first to comment

I have now stared building my robot and I wanted to use parts so I had to machining as little as possible.

I thought of using 4 standard 6mm threaded rod and 3 nail ink and some nuts and washers as in the image below.

This should be parts that every one can find in there local hardware stores..

I’m a little concerned of the heavy weight of this structure but it’s a little below 1 kg. It will be cleared after a test run.

Code for KasBot V1

Posted in Arduino, Self balancing robot on November 7th, 2010 by x-firm – Be the first to comment

The Balancing Robot for dummies thread have bean a great help for me to make a jump start in this type of projects. The least I can do is to host the code for this great robot and here it is:

KasBot V1 complete code file:
K_BotV1.rar

KasBot V1 is fully functional and should balance for ever
Just modify the code according to your own gyro sensitivity

If you want to use the Balancing Bot GUI, then use the files below:

KasBot V1 serial complete code file:
K_BotV1_serial.rar (modified to work with the Balancing Bot GUI)

GUI Sketch for Processing IDE:

Download and unzip the folder in your sketch directory. Change the serial port to the corresponding for you computer…

Complete sketch

Currently you will see trends for the following values:
- ACC_X, _Y, GYR_Y
- actAngle, ACC_angle
- pTerm, iTerm, dTerm
- drive

More info on the thread at the Arduino forum…

The balancing bot GUI beta

Posted in Processing, Self balancing robot on November 5th, 2010 by x-firm – Be the first to comment

Heres the first beta version of the Balancing Bot GUI and it includes one widget that are a dynamic graph…

  • You can add as many graphs as you want and set the size and shape of them.
  • You can maximiz a graph
  • You can also move it in real time

Right now you can only show information from the bot, but I will soon update the GUI with the possibility to change parameters in the bot.

Below is a image of the GUI that are using three Graph widgets:

Heres the code from the example above…

Sketch for Processing IDE:

Download and unzip the folder in your sketch directory. Change the serial port to the corresponding for you computer…

Complete sketch