Difference between revisions of "S14: Quadcopter"

Revision as of 19:59, 17 April 2014

Grading Criteria

Quadcopter

Abstract

Our team aims to build a Quadcopter (Quad-rotor helicopter), which is a multi-rotor aerial vehicle that is lifted and propelled by four rotors. The thrust generated by the propellers lifts the Quadcopter while the flight controller system govern the rotor speed for attitude control. A wireless remote control is used to interact with the flight controller system for changing the flight path. Our objective would be todesign and build a flight controller system that stabilizes the flight and accept commands from a hobbyist remote control during its flight.

Objectives & Introduction

The scope of our project can be divided into three parts:

• Design and build interfaces to all the on-board electronic sensor such as IMU, barometer and distance sensors
• Design and build interfaces to telemetry and radio modules to communicate with remote control and the computer
• Process the various sensor inputs and control the brushless motors on board using an electronic speed control system to stabilize the aircraft

Team Members & Responsibilities

1. Sree Harsha
   • PWM Design, Remote Control Input, Quadcopter assembly
2. Balaji
   • Sensor Data Processing, Quadcopter Assembly
3. Divya Kamath
   • Flight Controller Design, Code Integration

Schedule

Parts List & Cost

Backup Parts & cost

Design & Implementation

The design section can go over your hardware and software design. Organize this section using sub-sections that go over your design and implementation.

Hardware Design

Discuss your hardware design here. Show detailed schematics, and the interface here.

Pin Connections

Hardware Interface

In this section, you can describe how your hardware communicates, such as which BUSes used. You can discuss your driver implementation here, such that the Software Design section is isolated to talk about high level workings rather than inner working of your project.

Current Design UART for reading sensor data PWM for motor control UART for telemetry

Software Design

MPU-9150

The MPU-9150 consists of a 3-axis accelerometer, 3axis Gyroscope and a 3 axis magnetometer. its a one chip IMU solution with onboard Motion processor for sensor fusion.Though it inherently supports on board Sensor Fusion, the IP is undisclosed. Therefore we used the library for arduino by Pansenti. (https://github.com/Pansenti) The 6 axis sensor fusion (accel+gyro) is done on the MPU and sent to an arduino where the magnetometer data is used for YAW correction. The arduino transmits the orientation data over UART which is recieved by the SJONE for further processing.

For testing, we coded a GUI in python. The code parses the serial data from the arduino and displays the orientation of the IMU in real-time using Vpython.(video and code to be linked).

PID Controller

For our flight controller algorithm, we are using a PID controller. PID (proportional, integral, derivative) controller is a feedback control system which attempts to minimize the error in the output using three constant values: P, I and D i.e. the proportional, integral and derivative values.

Converting Remote Control Data to Motor Speed

The following steps are involved in converting raw RC (remote control) data to motor speed

1. 1. Get the RC data. Usually a PWM signal
2. 2. Scale up/down this value using a pre-decided curve. (Linear/Exponential)
3. 3. Apply PID on Roll/Pitch/Yaw data.
4. 4. Convert the output of PID into angles.
5. 5. Adjust the angles with the angles calculated by IMU (Inertial Measurement Unit)
6. 6. Use these angles to adjust motor speeds and direction

Implementation

This section includes implementation, but again, not the details, just the high level. For example, you can list the steps it takes to communicate over a sensor, or the steps needed to write a page of memory onto SPI Flash. You can include sub-sections for each of your component implementation.

Mechanical Design

Testing & Technical Challenges

Describe the challenges of your project. What advise would you give yourself or someone else if your project can be started from scratch again? Make a smooth transition to testing section and described what it took to test your project.

Include sub-sections that list out a problem and solution, such as:

My Issue #1

Discuss the issue and resolution.

Conclusion

Conclude your project here. You can recap your testing and problems. You should address the "so what" part here to indicate what you ultimately learnt from this project. How has this project increased your knowledge?

Project Video

Upload a video of your project and post the link here.

Project Source Code

Send me your zipped source code and I will upload this to SourceForge and link it for you.

References

Acknowledgement

Any acknowledgement that you may wish to provide can be included here.

References Used

1. https://github.com/Pansenti
2. https://code.google.com/p/sf9domahrs/
3. http://www.rcgroups.com/forums/showthread.php?t=1284741
4. http://blog.oscarliang.net/quadcopter-pid-explained-tuning/
5. http://aeroquad.com/showthread.php?1167-Stable-Mode-Explained
6. http://www.ece.ucdavis.edu/~spencer/195/datasheets/PID-Without-a-PhD.pdf
7. http://support.motioneng.com/downloads-notes/tuning/pid_overshoot.htm

Appendix

You can list the references you used.