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The CE150 is a laboratory helicopter made by Humusoft. It is used for studying system dynamics and control engineering principles from the theoretical point of view and enables a wide range of practical experiments in the fields of modelling, simulation and control. The laboratory helicopter set-up comprises a helicopter body carrying two motors, which drive the main and the tail propeller of the helicopter, and a servomechanism, which shifts the centre of gravity by moving a weight along the helicopter’s horizontal axis. The helicopter body is connected to a base so that two degrees of freedom are enabled:  
 
rotation around the horizontal axis pitch angle ψ  
rotation around the horizontal axis azimuth φ.  
 
The axes of the main and tail rotor and the vertical and horizontal helicopter axis are perpendicular to each-other. The helicopter model can be represented as a non-linear multi-variable system with three inputs (measured in machine units [–1 ,1]):  
 
u₁ – voltage driving the main motor;  
u₂ – voltage driving the tail motor;  
u₃ – position of the servomechanism (weight);  
 
and two outputs (measured in radians):  
 
ψ – pitch angle;  
φ – azimuth.  
 
The inputs u₁, u₂ and u₃ are measured in machine units ranging from –1 to 1. An interface unit, which connects the helicopter and the computer, converts the inputs from machine units to appropriate voltage values that drive the motors.  
Output ψ denotes the pitch angle, i.e. the angle between the vertical axis and the longitudinal axis of the helicopter body, whereas φ denotes the azimuth, i.e. the angle in the horizontal plane between the longitudinal axis of the helicopter body and its zero position. Both angles are measured in radians.  
 
The voltage driving the main motoru₁ and the voltage driving the tail motor u₁ affect both the pitch angle ψ and the azimuth φ, therefore we can say that the mentioned interactions make the system multivariable. However, it is possible to fix one (or both) degree of freedom by tightening the intended screw(s) in the helicopter base when needed.  
 
There are analogue connections between the helicopter and the interface unit, which converts the signals from analogue to digital and vice versa. The interface unit is connected to a computer via a multifunction input/output card. All the experiments are done in Matlab-Simulink environment using Real Time Toolbox.  
 
CE150 je laboratorijski model helikopterja, ki ga proizvaja podjetje Humusoft. Uporablja se pri raziskovanju dinamike sistemov in različnih pristopov vodenja s teoretičnega vidika in omogoča izvedbo širokega nabora praktičnih eksperimentov na področju modeliranja, simulacije in vodenja.  
Model je sestavljen iz trupa helikopterja z dvema motorjema, ki poganjata glavni in repni rotor helikopterja, in servomehanizem, ki lahko premika težišče helikopterja s prestavljanjem uteži vzdolž vodoravne osi helikopterja. Trup je pripet na podstavek, ki omogoča dve prostostni stopnji gibanja:  
rotacija okrog vodoravne osi - naklon ψ  
rotacija okrog navpične osi - odklon φ  
Osi glavnega in repnega rotorja sta pravokotni. Dinamiko helikopterja lahko opišemo z nelinearnim multivariabilnim sistemom s tremi vhodi:  
u₁ – napetost na glavnem motorju;  
u₂ – napetost na repnem motorju;  
u₃ – položaj uteži;  
 
in dvema izhodoma:  
 
ψ - naklon;  
φ– odklon.  
 
Vhodi u1, u2 in u3 so izraženi z normiranimi vrednostmi na intervalu od –1 do 1. Vmesnik, ki povezuje helikopter in računalnik, pretvarja normirane vrednosti v ustrezne napetosti. Izhod ? označuje naklon, tj. kot med navpično osjo in vzdolžno osjo trupa, izhod ? pa označuje odklon v vodoravni ravnini med vzdolžno osjo trupa in ničnim položajem. Oba kota sta določena v radianih.  
Napetost na glavnem motorju u1 in napetost na repnem motorju u2 vplivata tako na naklon ? kot na odklon ?. Križne povezave v sistem vnašajo multivariabilni značaj. Po potrebi je mogoče sistem omejiti na eno prostostno stopnjo s privijačenjem trupa v osnovni položaj.  
Analogni signali se v vmesniku pretvarjajo v digitalne in obratno. Vmesnik je na računalnik priključen z večfunkcijsko vhodno-izhodno kartico. Vse eksperimente je mogoče izvajati v okolju Matlab-Simulink z orodjem Real Time Toolbox.  
Več informacij je na spletni strani podjetja Humusoft.  
 
Contact: gorazd.karer(at)fe.uni-lj.si  
 
More information is available on Humusoft homepage.

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