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Control of a Quadrotor

Hansson, Niklas and Rudner, Mikael (2011) In ISSN 0280–5316
Department of Automatic Control
Abstract (Swedish)
The objective of this thesis is to investigate the use of commercial devices as user interfaces on a quadrotor and to investigate solutions to the problem of slung load control. A slung load is a uniform mass attached with a wire which is allowed to swing freely to the bottom of the quadrotor. The purpose of substituting the radio control (RC) controller with a commercial smartphone is that they are more easy to grasp and might therefore be easier to use for a novice than an RC controller. The existing radio control link does not exist on a smartphone so it was complemented by a wireless network connection via transmission control protocol (TCP) or user datagram protocol(UDP). The smartphone does not have the same interface as the RC... (More)
The objective of this thesis is to investigate the use of commercial devices as user interfaces on a quadrotor and to investigate solutions to the problem of slung load control. A slung load is a uniform mass attached with a wire which is allowed to swing freely to the bottom of the quadrotor. The purpose of substituting the radio control (RC) controller with a commercial smartphone is that they are more easy to grasp and might therefore be easier to use for a novice than an RC controller. The existing radio control link does not exist on a smartphone so it was complemented by a wireless network connection via transmission control protocol (TCP) or user datagram protocol(UDP). The smartphone does not have the same interface as the RC controller either so the same functionalities were implemented by using the touch screen and the inertial measurement unit (IMU) of the smartphone. However, this requires altitude control since the lack of multitouch in Android does not allow several inputs at the same time, thus making it impossible to adjust the thrust as the pitch and roll is adjusted. Another commercial device that was investigated was a PlayStation 3R gamepad (PS3 gamepad), whose joysticks were very similar to the RC controller’s but its shape was smaller and more ergonomic. It also communicated via TCP or UDP over a wireless network connection. The purpose of slung load control is to reduce the oscillations of the slung load and its effect on the quadrotors flight performance, thus
enabling it to handle heavier loads. The slung load control consisted of several subproblems; model of a slung load, altitude control, filtering of noisy sensors and the slung load control itself. These were all solved but the last one where the slung load control was not implemented on the quadrotor due to lack of time. The model of the slung load was done by
letting the dynamics of two traversed simple pendulums approximate the slung load’s angular movement. The altitude control consists of a PID controller extended with anti-windup and bumpless transfer which is combined with a feedforward control of the tilt angle. The controller acts upon a low-pass filtered pressure sensor as a measurement signal and receives its setpoint from one of the commercial devices mentioned above. The low-pass filter of the pressure sensor is a second order Butterworth filter, whose purpose is to reduce noise and the impact of spikes induced by events in the surroundings. (Less)
Please use this url to cite or link to this publication:
author
Hansson, Niklas and Rudner, Mikael
supervisor
organization
year
type
H3 - Professional qualifications (4 Years - )
subject
publication/series
ISSN 0280–5316
other publication id
ISRN LUTFD2/TFRT--5910--SE
language
English
additional info
Month=May
Year=2011
id
3403988
date added to LUP
2013-01-21 11:25:12
date last changed
2013-01-21 11:25:12
@misc{3403988,
  abstract     = {The objective of this thesis is to investigate the use of commercial devices as user interfaces on a quadrotor and to investigate solutions to the problem of slung load control. A slung load is a uniform mass attached with a wire which is allowed to swing freely to the bottom of the quadrotor. The purpose of substituting the radio control (RC) controller with a commercial smartphone is that they are more easy to grasp and might therefore be easier to use for a novice than an RC controller. The existing radio control link does not exist on a smartphone so it was complemented by a wireless network connection via transmission control protocol (TCP) or user datagram protocol(UDP). The smartphone does not have the same interface as the RC controller either so the same functionalities were implemented by using the touch screen and the inertial measurement unit (IMU) of the smartphone. However, this requires altitude control since the lack of multitouch in Android does not allow several inputs at the same time, thus making it impossible to adjust the thrust as the pitch and roll is adjusted. Another commercial device that was investigated was a PlayStation 3R gamepad (PS3 gamepad), whose joysticks were very similar to the RC controller’s but its shape was smaller and more ergonomic. It also communicated via TCP or UDP over a wireless network connection. The purpose of slung load control is to reduce the oscillations of the slung load and its effect on the quadrotors flight performance, thus
enabling it to handle heavier loads. The slung load control consisted of several subproblems; model of a slung load, altitude control, filtering of noisy sensors and the slung load control itself. These were all solved but the last one where the slung load control was not implemented on the quadrotor due to lack of time. The model of the slung load was done by
letting the dynamics of two traversed simple pendulums approximate the slung load’s angular movement. The altitude control consists of a PID controller extended with anti-windup and bumpless transfer which is combined with a feedforward control of the tilt angle. The controller acts upon a low-pass filtered pressure sensor as a measurement signal and receives its setpoint from one of the commercial devices mentioned above. The low-pass filter of the pressure sensor is a second order Butterworth filter, whose purpose is to reduce noise and the impact of spikes induced by events in the surroundings.},
  author       = {Hansson, Niklas and Rudner, Mikael},
  language     = {eng},
  note         = {Student Paper},
  series       = {ISSN 0280–5316},
  title        = {Control of a Quadrotor},
  year         = {2011},
}