Mechanical Engineering The University of Adelaide Australia

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Robotics Group



School of Mechanical
Engineering

THE UNIVERSITY OF
ADELAIDE
SA 5005
AUSTRALIA

Telephone:
+61 8 8303 5460
Facsimile:
+61 8 8303 4367

Quanser 2DOF Heli Projects by Ben S. Cazzolato Rotational Inverted Pendulum
Project Picture
Photo of Ben Cazzolato

Ben Cazzolato

Quanser 3DOF Hover

Ben S. Cazzolato


Keywords: Quanser 3DOF Hover, quadrotor

(Commenced: 01-Jan-2004,Concluded: 12-Dec-2005)

Background

In 2004 the Sir Ross and Sir Keith Smith Fund awarded the School of Mechanical Engineering a grant to purchase two Quanser aerospace rigs for teaching control; the 2DOF Heli and the 3DOF Hover. These rigs have now been fully commissioned and are used for teaching both undergraduate and postgraduate students. The teaching tools developed in the School of Mechanical Engineering have been posted here so others may benefit. Many errors were found in the manuals and software. We have endeavoured to correct these in the documentation below.



3DOF Hover


The 3DOF Hover system consists of a frame with 4 propellers mounted on a 3 DOF pivot joint such that the body can freely roll, pitch and yaw. The propellers generate a lift force that can be used to control the pitch and roll angles. The total torque generated by the propeller motors causes a yaw to the body as well. Two propellers in the system are counter-rotating propellers such that the total torque in the system is balanced when the thrusts of the 4 propellers are approximately equal. Motion about the three degrees of freedom is measured using two encoders. All electrical signals to and from the body are transmitted via a slipring thus eliminating the possibility of tangled wires and reducing the amount of friction and loading about the moving axes.

Hover Tutorial and Manual

A tutorial on the 3DOF Hover has been written (based on the manual supplied by Quanser). This document contains the correct information about the linearised state equations and the various parameters needed to model the system.

Hover State Model

A Simulink model of the Hover system has been built, including a VRML (Virtual Reality Model). This model has state augmentation to remove any steady state errors and allows the user to toggle between full state feedback and control using an estimator. You will need the image file for the Simulink model. Save all these in your working directory. These files will allow you to model the plant in virtual reality.

If you do not have a joystick, then you will need to delete the joystick block otherwise you will get a signal dimension error.

In order for the model to run you will need to answer all the questions in the tutorial (above). If you do not wish to do these yourself, you can contact me an I will provide you with the necessary m file to define the system gains and matrices. Alternatively, the m file provided with the rig will get you half way there.

Hover IO Blocks for Quanser MultiQ Board

A Simulink library has been written for the Quanser MultiQ board and the Quanser 3DOF Hover. There is a joystick input and an I/O block for the DACs and encoders. The joystick we use is a modified 3DOF Logitech ExtremePro 3D. This provides pitch, roll and yaw control. You will need the Hover image too.

If you compare this library with the Simulink model supplied with thr rig, you will notice that the gain of 1/5 has been removed from the DAC section. This gain was erroneously added to account for the gain of 5 across the UPM amps. However the torque constants used in the derivation (by myself and Quanser) of the state equations are from the voltage input to the amp (not the motor).

There are several accurate Simulink models available for doing real time control on the 3DOF Hover platform using Quansers WinCon and a MultiQ board. These are based on the Simulink model above. These can be provided upon request.






Sir Ross and Sir Keith Smith Fund

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