Gesture Controlled Quadcopter

(Arduino as Flight Controller)

Abstract:

This Project shows the controlling of quadcopter using gestures. We designed our own control strategy and implemented in Arduino UNO. The sensors like accelerometer, gyroscope attached to the quad copter sense the movement and orientation of quad copter. For controlling the motion of the quadcopter on three directions using gestures in which mobile phone acts as a gesture tool.

Mechanical Design:

Hardware Components Used:

• Arduino UNO
• ESP8266
• MPU-6050
• Burshless Motors 1000KV-4
• Electronic Speed Controllers-4
• 4-legged Frame
• Lipo Battery 5200mAh

Generally flying a quadcopter is divided into two configurations.

Such as X-Configuration and P-Configuration.

The motor rotations of quad is as shown

We choose X-Configuration to fly our quadcopter.

Controlling motion of X-Configured Quad:

• If the quad needs to take off without any drift i.e., only in z-direction then only the throttle must be given rest all other to be in normal position.
• If the quad needs to move forward, then speed of motors 1 and 4 should be reduced accordingly and speed of motors 2 and 3 should be increased. This motion is known as pitch.
• If the quad needs to move right-side then the speed of motors 1 and 2 should be reduced and speed of motors 2 and 4 must be increased. Similarly, to move left side the speed of motors 1 and 2 must be increased and the speed of motors 3 and 4 must be decreased. This motion of the quad is known as roll or aileron.
• If the quad needs to be self-rotated in clockwise then speed of motors 1 and 3 are to reduce and speed to motors 2 and 4 must be increased. If the quad needs to be self-rotated in counterclockwise direction then the speed of the motors 2 and 4 must be decreased and speed to motors 1 and 3 must be increased. This motion of the quad is knowing as yaw.

This entire thing is given in equation form as follows:

esc_1 = throttle - pid_output_pitch + pid_output_roll - pid_output_yaw; //Calculate the pulse for esc 1 (front-right - CCW)

esc_2 = throttle + pid_output_pitch + pid_output_roll + pid_output_yaw; //Calculate the pulse for esc 2 (rear-right - CW)

esc_3 = throttle + pid_output_pitch - pid_output_roll - pid_output_yaw; //Calculate the pulse for esc 3 (rear-left - CCW)

esc_4 = throttle - pid_output_pitch - pid_output_roll + pid_output_yaw; //Calculate the pulse for esc 4 (front-left - CW)

These are the values given to respective Electronic Speed Controllers which gives the speed for motors.

Our Controller uses closed loop controllers to ensure its stability and manoeuvrability. We use Proportional-Integral-Derivative (PID) controllers.

When the quad copter orientation is changed in any pitch/roll/yaw axis, the gyros indicate an angular change from its initial position. The quad copter controller tries to correct the error calculated between a measurement at the controller output (measured by the gyros) and an input set point (position of the stick), and drives the motors to attempt to return the quad copter to its initial position.

PID Controller:

Generalized PID equation is

u(t) = Kp*e(t) + Ki* ∫e(τ)dτ + Kd* d/dt(e(t));

where Kp,Ki,andKd, all non-negative, denote the coefficients for the proportional, integral, and derivative terms, respectively (sometimes denoted P, I, and D)

_ Basic PID Tuning: _

Default values should be used as a starting point, this will help us to know the difference after changing some parameters. Those value are well suited for the average quad copter.

1. Ensure CofG is in the middle of our copter, move battery to get it there.
2. Set motors running at approx. 50% if we have props on be very careful, check GUI trace for an almost flat line from gyro and acc
3. if trace is dancing all over the place we have vibrations issues and it needs to be sorted before proceeding.

Keep in mind that P is the dominant part of PID and gets we in the ballpark for good flight characteristics.

With props on:

1. Set PID to their default value
2. Hold the quad copter securely and safely in the air
3. Increase throttle to the hover point where it starts to feel light
4. Try to lean the quad copter down onto each motor axis
5. We should feel a reaction against our pressure for each axis.
6. Change P until it is difficult to move against the reaction.
7. Now try rocking the quad copter along the Pitch axis (front to back). Increase P until it starts to oscillate and then reduce a touch.
8. Repeat for Yaw Axis.

Gesture Control Mechanism:

• In our project we are using mobile phone as a gesture control device. We made an app that could sense orientation of the mobile phone and these values are transmitted to Arduino using ESP8266.
• A smart phone consist of gyro and accelerometer and these values are retrieved by the app which in turn process and sends required values to the controller on the quad with the help of ESP8266.
• For example, if the quad needs forward pitch inclines the phone forward and for backward pitch incline the phone backward. Similarly, if the quad needs to move right side incline the phone to right ward and for left side motion of the quad incline the phone to left side.

Image of our app:

In app there is a slide bar which helps us to control the throttle value of the quad and buttons 'YAW DEC' and 'YAW INC' for controlling yaw motion of the quad.

Failsafe:

This is method for protection of quad. That is, if the connection between ESP8266 and mobile phone has lost then controller present on the quad zeros the values of the motors.

In app there is a button called 'GO' which also acts as a Failsafe button, I.e., we should always hold the go button or else communication between ESP and mobile phone will be lost.

The values present on the app are default values.

This is the video link of our project GESTURE CONTROLLED QUADCOPTER:

DEMO: https://photos.app.goo.gl/C135fo6UNZSrPEw98

Setup instructions

Websocket and MultiWii serial code to control a quadcopter, running on a Raspberry Pi

Overview of all the tech

• The first thing to do is to create a hosted Wi-Fi network. To accomplish this we use isc-dhcp-server and hostapd
  • isc-dhcp-server serves as the DHCP server for our Wi-Fi network
  • hostapd serves as access point management, essentially making a Wi-Fi card into a router
• Now for communication with our MultiWii device. I have a C library with the MSP protocol, and I use a backbone library libserialport
  • libserialport is downloaded from their git repository, and installed
  • cMultiWii, my MSP implementation is downloaded from the git repository. This will be compiled later
• Websocket communication is needed next. I use the websocketpp library, implemented in this repo.
  • websocketpp is not installed. It is a header-only library (.hpp), and is compiled each time (with the intention of improving performance)
• Compiling websocket.cpp in this repo will build the executable that will recieve commands from a remote control, and then relay them to the MultiWii. It compiles the websocketpp library which takes along time, and the cMultiWii library which is quick to compile.

Instructions to set up your Pi with all of the software it needs:

• Download/clone this repo
• Run setup_pi_software.sh, which will install libserialport, isc-dhcp-server, hostapd, and download cMultiWii, websocketpp. It will also compile the websocket server
  • You need to check to see if your MultiWii is /dev/ttyUSB0. Check the troubleshooting section for more information
• Since your network configuration and device might be different, your /etc/network/interfaces, /etc/default/isc-dhcp-server, and /etc/dhcp/dhcpd.conf files are not automatically modified.
• Add the following configuration to your /etc/network/interfaces file in order for hostapd to work. Also, remove any reference to wpa_supplicant, as it causes issues with hostapd

allow-hotplug wlan0
iface wlan0 inet static
  address 192.168.10.1
  netmask 255.255.255.0
  gateway 192.168.10.1

• Add the following configuration to your /etc/default/isc-dhcp-server file in order for isc-dhcp-server to know what device to use

INTERFACES="wlan0"

• Add the following configuration to your /etc/dhcp/dhcpd.conf file in order for isc-dhcp-server to know what subnet to use

subnet 192.168.10.0 netmask 255.255.255.0 {
    range 192.168.10.1 192.168.10.30;
}

• You need to ensure wlan0 and hostapd.conf are correct. check the troubleshooting seciton for more information

Running the program and automatic startup

• I would suggest a reboot after all of the installation process
• To start up the hosted network and the websocket, run sudo ./piquadcopter.sh
• To schedule everything to start up automatically on boot, edit /etc/rc.local with something like... /home/path/to/piquadcopter.sh.
  • rc.local is called automatically on startup.
  • Check troubleshooting for more help

Troubleshooting

• To find your wireless interface, run ifconfig
• To find your USB device, run dmesg | grep ttyUSB and look for what number it is
  • Once you find your device, you will need to edit line 4 of configure_port.c within cMultiWii to reflect the proper device. You will have to recompile.
• If your wireless interface is not wlan0, then you will have to change it in your interfaces file, and in hostapd.conf
• Check /etc/hostapd/hostapd.conf for hostapd configurations, and make sure they match your interfaces configuration
• If hostapd is throwing errors similar to: n180211: Could not configure driver mode ... then you probably need to kill the instance of hostapd already running.
  • Run ps -A to view all active processes
  • Find the process ID number for hostapd
  • sudo kill <process ID> will kill hostapd and hopefully resolve the issue
• If there are any problems with isc-dhcp-server, try running sudo journalctl -u isc-dhcp-server.service to look for errors
• If you need to recompile at any time, just run make at the top level of this repository