X1 Robotics R&D

7/21/2019 X1 Robotics R&D

http://slidepdf.com/reader/full/x1-robotics-rd 1/12

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X1 Robotics Semi-Autonomous Quadcopter

Research and Development



Semi - Autonomous Quadcopter

with ability to fly in 6 Cartesian

directions: +/-X, +/-Y, +/-Z.

Controlled by IOS application

with communications from

iPhone to onboard Raspberry Pi

via Wifi Direct.

Flight software and controls willbe coded onto Arduino Mega

2560 and will receive directional

information from Raspberry Pi.

Initial X1 Design

Overview



4 rotors: Rotors 1&0 spin the

same direction. Rotors 2&3 spin

opposite direction of 1&0.

Roll, Pitch and Yaw (Euler Angles)

can describe instantaneous 3D

orientation of vehicle and are

measured in degrees.

Flight software will be based oncalculating and correcting the

error in instantaneous roll, pitch

and yaw of the device.

How a

Quadcopter Flies 1

2

0

3

x

y



Using diagrams to right: To go forward,

motor 2 will decrease thrust while motor 3

will increase an equal amount of thrust.

This causes a delta upward thrust of zeroalong with a forward velocity.

Movement in yaw direction is achieved by

increasing power to 1&0 while decreasing

2&3.

This examples uses a + formation. An X formation uses the same basic principles of

flight, but with forward being defined as the

45 degree angle between motors 1 & 2.

How a Quadcopter

Flies (2)

x

y



X1 IOS Application Design

“Startup” button causes rotors to spin

with low thrust (Copter still on ground).

“Initialize” causes copter to begin to

hover about a meter off the ground.

“Shutdown” causes Quadcopter to

slowly lower itself to the ground and

turn of motors.

All other controls are self explanatory.

This app will allow the user to send

directional signals from iPhone, to

Raspberry Pi.

Startup Initialize

Up Down

Forward Backwards

Left Right

X1

ROBOTICS

Shutdown

Example Screen



X1 Instruments and Processor Assignments

Communicate with iPhone app.

Send basic 5V logic signals to Arduino

microprocessor using digital I/O pins to

control the 9 buttons explained on Appdesign slide.

Raspberry Pi capabilities will be used

for future models (X2, X3 etc…) for

improvements such as, Camera feed,

stereo, GPS Nav, etc…

X1 design of Raspberry Pi is fairly

simple while complex flight software is

left to the Arduino in order to save

space on the Pi for later improvements.

Raspberry Pi Responsibilities



X1 Instrument and Processor Assignments

Utilizes 3 axis accelerometer, 3 axis

gyroscope, and 3 axis magnetometer

to calculate 3D orientation in space.

Will output serial data to Arduinowhich will be used to calculate Roll,

Pitch, and Yaw.

Some IMU’s have built in

Microprocessors on them, as to save

space for flight software on Arduino.IE, the real time Roll, Pitch and Yaw

values could be calculated before

even being sent to the Arduino to be

analyzed.

Inertial Measurement Unit(IMU)





Flight Software Design

Step One: Use IMU to

calculate real time roll,

pitch and yaw.

Step Two: Use signals from

raspberry pi to set current

desired direction and IMU

data to find current

orientation, and use PID

controller to correct roll,

pitch and yaw error.



Flight Software Design (2)

A PID controller calculates an 'error' value as the

difference between a measured [Input] and a desired

set-point. The controller attempts to minimize the error

by adjusting [an Output].

Proportional Element: Fixes immediate error usingproportional constant. Just a proportional controller will

lead to high oscillations and offset error.

Integral Element: Serves as a “memory” for error over

time. High integral Coefficient leads to high set-point

overshoot.

Derivative Element: Serves to look at the Rate of

Change of error with time, as to “predict” future error

correction.

A good PID controller will have finely tuned coefficients

for each element, and allow for fast error correction

without excessive oscillations and instability.

PID Controller



Flight Software Design (3)

In Arduino IDE

(1): Set all initial Conditions, variables,

parameters, functions, etc…

(2): In “void setup()” declare all pin I/O’s and run

function to arm motors and speed controller. Runstartup and initialize functions to get Quad

hovering right above ground.

(3): in “void loop()” use switch function to define 6

different modes, one for each direction the copter

should fly.

(4): In each case of switch function, define thenew motor PWM’s and angle set points for PID

controller. Loop until shutdown process initialized.

(5): Run one final loop to slower lower quad to

ground and shutdown all systems.

Pseudo CodeExample code

}

}

Step 1

Step 2

}Step 3,4

and 5



Hardware

DC Brushless motors

Rotors

Chassis/Frame

Electronic Speed

Controllers

Lithium Ion

Rechargeable Battery

Documents

X1 Robotics R&D