TWIN ROTOR MIMO SYSTEM 33-007

Introduction

The Twin Rotor Multi-Input Multi-Output (MIMO) System has been

designed to provide a high-order, non-linear, MIMO system with

significant cross-coupling. Its behaviour resembles that of a helicopter,

however, the angle of attack of the rotors is fixed and the aerodynamic

forces are controlled by varying the speeds of the motors.

Features

n Classic multivariable system.

n Non-linear processes.

n Closed loop identification.

n High resolution, optical encoder feedback.

Controllers

1-DOF and 2-DOF Controllers

1-DOF Controllers

n Vertical stabilisation and tracking.

n Horizontal stabilisation and tracking.

2-DOF Controllers

n Vertical and horizontal simultaneous stablisation and tracking.

Modelling & Simulation

Mathematical models for 1DOF + 2DOF

Simulation of Mathematical models.

Description T

he Twin Rotor MIMO System is a convincingly scaled model of a

non-linear dynamic MIMO system. It simulates the main and tail rotor

systems of a helicopter with their very strong interactions. High

resolution optical encoders provide feedback from the vertical and the

horizontal angular positions of the connecting arm.

The system consists of the arm and rotor assembly, computer interface

card, connecting cables and manual.

In addition a remote cable connected On/Off control box is provided to

enable the unit to be switched on or off without the need for the

operator to enter the workspace of the unit when in motion.

The controllers are implemented with full PID elements having the form

as follows:

where u(t) is the control output

and the error, e(t), is defined as

e(t) = desired value - measured value of quantity being controlled.

The control gains

Kp , Ki and Kd

determine the weight of the contribution of the error, the integral of the

error, and the derivative of the error to the control output and will dictate

the response of the closed-loop system to the initial conditions input.

1 DOF constrained to horizontal motion by the locking screw

In this mode the horizontal angle is the PID control variable.

1 DOF constrained to vertical motion by the locking screw

In this mode the vertical angle is the PID control variable.

2 DOF motion

In this mode the horizontal & vertical angles are the PID control variables.

The output of the PID controller will produce the control value for the D/A

converter and as a result the voltage outputs to the tail and main rotor

motors, hence rotation of the beam around horizontal and vertical axis.

 

1-DOF PID Tail Rotor

Control

The tail rotor control problem is shown in the figure below.

This represents a side-view of the system when the motion has been

constrained by the vertical set screw to be in the horizontal plane.

The goal of this Controller will be to demonstrate positioning of the

system along a desired trajectory for µh.

The Kp, Kd and Ki parameters can be modified in real time for tuning

the controller.

 

 

1-DOF PID Main

Rotor Control

The main rotor control problem is shown in the figure below.

This represents a side-view of the system when the motion has been

constrained by the horizontal set screw to be in the vertical plane.

The goal of this Controller will be to demonstrate positioning of the

system along a desired trajectory for µv.

SIMULINK

® model for 2 x DOF PID Control

2-DOF PID Tail and

Main Rotor Control

The goal of this experiment is to control both the tail and the main

rotors simultaneously.

NOTE

In all the demonstration models, the Kp, Ki and Kd parameters can be

modified in real time to allow the performance to be tuned while the

control program is running.