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Two Wheel Balancing Robot

Question asked by deepakbhatia93 in #Robotics on Feb 26, 2015
deepakbhatia93 · Feb 26, 2015
Project Abstract / Summary : INTRODUCTION
As the name implies ‘Two Wheel Balancing Robot’ it has the ability to balance itself on the two wheels. It will be prevented from falling by giving acceleration to the wheels according to its inclination from the vertical. If the bot gets tilted by an angle, then in the frame of the wheels the centre of mass of the bot will experience a pseudo force which will apply a torque opposite to the direction of tilt.
  • Main Frame : 3 layered chasis made up of ceramic sheets
  • Motors: Two 300 rpm DC geared motors.
  • ATMEGA328: 8 bit AVR microcontroller used on arduino platform
  • MPU6050: this chip contains a 3-axis gyroscope and a 3-axis accelerometer. This makes it a “6 degrees of freedom inertial measurement unit” or 6DOF IMU, for short. Other features include a built in 16-bit analog to digital conversion on each channel and a proprietary Digital Motion Processor™ (DMP) unit.
  • L293D: 16Pin motor driver IC.
  • I2C Level Converter: It is used as an interface between MPU6050 and microcontroller for bidirectional serial data transfer.
WORKING Its working is based on the feedback control mechanism.
Input – After giving power supply to the robot, make it stand vertically by giving external support. MPU6050 takes 10 seconds to give its accelero and gyro values. Accelerometer gives acceleration in all the 3 coordinates with respect to the acceleration due to gravity. Gyroscope gives change in angle of inclination with respect to all 3 axis. Sensor communicates with the microcontroller through I2C bus
Processing- Microcontroller saves the input data(accelero and gyro values) after 10 seconds.
After removing the support robot tilts in either forward or backward direction, sensor values starts changing simultaneously. These real time values are fed back to the microcontroller.
Microcontroller finds the error between initial and real time value.
We use PID mechanism to minimize the error. Aproportional-integral-derivative controller(PID controller) is acontrol loopfeedback mechanism(controller) widely used inindustrial control systems(Programmable Logic Controllers,SCADAsystems,Remote Terminal Unitsetc). A PID controller calculates an "error" value as the difference between a measured process variable and a desired set point. The controller attempts to minimize the error in outputs by adjusting the process control inputs.
The PID controller algorithm involves three separate constant parameters, and is accordingly sometimes called three-term control: the proportional, the integral and derivative values, denoted P,I and D.Simply put, these values can be interpreted in terms of time: P depends on the present error, I on the accumulation of past errors, and D is a prediction of future errors, based on current rate of change.The weighted sum of these three actions is used to adjust the speed of the motors.
Basic condition for balancing
Robot tilts forward—Error positive--- Motors move forward.
Robot tilts backward—Error negative—Motors move backward.
Speed of the motors directly depends on the magnitude of the error. We use pulse width modulation technique to adjust the speed.

The image of our project being made is attached along with. [​IMG]

Why did you choose to work on this project topic : Earlier Mobile robots either moved on four wheels or on two legs, however both models have drawbacks. Four wheels model can move faster and carry heavy load but cannot turn sharply as it takes relatively larger area to turn from one direction to another. Robots having two legs called Humanoid can turn easily with relatively smaller area but cannot move fast and cannot carry heavy loads. To overcome these drawbacks we are making a two wheel balancing robot which can take sharp turns covering small area and carry heavy loads that too being much energy efficient and at high speed.

Future scope
1. In manufacturing industry- especially at assembly stations and transporting material from one station to another.
2. Automatic wheelchairs that can climb the staircase using the concept of balancing.

Project Category : Robotics / RC / Automation
Institute/College Name: Guru Nanak Dev University
City: Amritsar
State: Punjab
Participating Team From: Final Year Posted in: #Robotics

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