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Vertical take Off and landing (currently offline: Experiment will be available on request)
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Vertical Take Off and Landing (VTOL) System

Current control Experiments

Experiment 1.

1.Click the perform experiment link to open the file as shown in figure3 below

figure3

2.Ensure the correct Device is chosen

3.Set the Current Control ON switch to ON.

4.RUN the application

5.In the Current Setpoint section set:

Amplitude=0.20 A, Frequency = 0.40 Hz, Offset =0.90 A

6. In the Control Parameters section set the PI current gains to: Kp_c = 0.250, Ki_c = 10

The VTOL Trainer propeller should begin turning at various speeds according to the current command. Examine the reference and measured current response obtained in the Current(A) scope. They should be tracking as shown in figure3 above.

Experiment 2

1.Show and explain the effect of not having any integral gain.

2.In the Control Parameters section set the PI current gains to: Kp_c = 0, Ki_c = 100.

Attach a sample response.

Experiment 3

Show and explain the effect of not having any proportional gain.

In the Control Parameters section set the PI current gains to: Kp_c = 0.250, Ki_c =0

Attach a sample response.

Record the time response parameters as per the following table by setting suitable sampling rates.

Calculate damping ratios for various percentage overshoots.

Finally click on the Stop button to stop the application.

 

 % Overshoot 0 1 2 5 8 10 15 20
tp(peak time)                
ts(rise time)                
ts(settling time)                

 

 

Modeling Experiments

1. Measure the Equilibrium current .

1.Click the perform experiment link to open the file as shown in figure1 below.

figure1

 

2.Ensure the correct Device is chosen

3. Set the Current Control ON switch to ON.

4. RUN the application

5. In the current control parameters, set PI gains to Kp_c=0.2 V/A, Ki_c=97.2 V/(A.s)

6. In the Current Setpoint section set : Amplitude=0.00 A, Frequency = 0.40 Hz, Offset =1.00 A .

7.Gradually increase the offset current until the VTOL Trainer is horizontal.

8.The pitch should read 0 degrees when the VTOL Trainer is horizontal.You may need to adjust the pitch offset by varying the VTOL Offset control. By default this is set to 25.0 degrees.

The current required to make the VTOL trainer horizontal is called the equilibrium current, Ieq.

9.Capture the pitch and current response and record this current.

Finally click on the Stop button to stop the application.

 

                                                                             

FLIGHT CONTROL EXPERIMENTS

PD Steady-State Analysis

 

1. Calculate the theoretical VTOL steady state error using a PD control with Kp=2 and Kd=1 and a step amplitude of R0= 4.0 degrees.

2. Click the perform experiment link to open the file as shown in figure1 below.

figure1

3.Ensure the correct Device is chosen

4. RUN the VI.

5. In the Position Setpoint section set: Amplitude=0.00 rad, Frequency = 0.15 Hz, Offset =0.0 rad

6. In the Position Control Setpoint section set:

kp= 1.0 A/rad, ki=2.0 A/(rad.s),kd=1.0 A.s/rad

 

7. Let the VTOL system stabilises about the 0.0 rad setpoint. Examine whether the VTOL Trainer body is horizontal..If not then you can adjust the pitch offset by varying the VTOL Offset control. By default this is set to 25.0 degrees.
 

8. To use a PD Control, in the Position Control Parameters section set:

 

kp= 2.0 A/rad, ki=0 A/(rad.s), kd=1.0 A.s/rad

 

9. In the Position Setpoint section set:

Amplitude= 2 rad, Frequency = 0.40 Hz, Offset = 2.0 rad .

 

The VTOL system should be going up and down and tracking the square wave setpoint.

 

Capture the VTOL device step response when using this PD controller and measure the steady state error.

10. In the Signal Generator section set Amplitude(rad) to 0 rad and slowly decrement Offset(rad) to -8.0 rad
 

Finally click on the STOP application to stop the application.

 
 

PID Steady-State Error Analysis

 

1. Calculate the theoretical VTOL steady state error using a PID control with Kp=2 and Kd=1 and a step amplitude of R0= 4.0 degrees.

2. Click the perform experiment link to open the file as shown in figure1 below.

figure1

3.Ensure the correct Device is chosen

4. RUN the VI.
 

5. In the Position Setpoint section set: Amplitude=0.00 rad, Frequency = 0.15 Hz, Offset =0.0 rad

6. In the Position Control Setpoint section set:

kp= 1.0 A/rad, ki=2.0 A/(rad.s),kd=1.0 A.s/rad

7. Let the VTOL system stabilises about the 0.0 rad setpoint. Examine whether the VTOL Trainer body is horizontal..If not then you can adjust the pitch offset by varying the VTOL Offset control. By default this is set to 25.0 degrees.

8. To use a PD Control, in the Position Control Parameters section set:

kp= 2.0 A/rad, ki=0 A/(rad.s), kd=1.0 A.s/rad

9. In the Position Setpoint section set:

Amplitude= 2 rad, Frequency = 0.40 Hz, Offset = 2.0 rad .

The VTOL system should be going up and down and tracking the square wave setpoint.

10. In the Position Control Parameter section, increment the integral gain until you reach ki= 4.0 A/(rad.s)
11. Capture the VTOL system step response when using a PID controller and measure the steady-state error.
12. To stop the control, in the Signal Generator section set Amplitude(rad) to 0 rad and slowly decrement Offset(rad) to -8.0 rad.
 
Finally click on the STOP application to stop the application.

 

PID Control Design


1. Find the Natural frequency Wn and damping ratio ζ required to meet a peak time of 1.0 seconds and Overshoot 20%.

2. Calculate the PID gains kp, ki and kd needed to meet the VTOL system specifications.

3. Click the perform experiment link to open the file as shown in figure1 below.
 
figure1
4.Ensure the correct Device is chosen
5. RUN the VI.
6. In the Position Setpoint section set: Amplitude=0.00 rad, Frequency = 0.15 Hz, Offset =0.0 rad
7. In the Position Control Parameters section, enter the PID gains founded in point 2. above
8 . Let the VTOL system stabilises about the 0.0 rad setpoint. The VTOL system body should be horizontal...If not, adjust the pitch offset by varying the VTOL Offset control. By default this is set to 25.0 degrees.

9.In the Position Setpoint section

kp= 2.0 A/rad, ki=0 A/(rad.s), kd=1.0 A.s/rad

10 . In the Position Setpoint section set:

Amplitude= 0.0 rad, Frequency = 0.40 Hz, Offset = 0.0 rad .

The VTOL system should be going up and down and tracking the square wave setpoint.

11 . Capture the response of the VTOL system when using your desired PID controller.
12. Measure the pick time and percentage overshoot of the measured response.
13. To stop the control, in the Signal Generator section set Amplitude(rad) to 0 rad and slowly decrement Offset(rad) to -8.0 rad.
 
Finally click on the STOP application to stop the application.
 

 

Enter all the values founded in the table below.
Parameters
Symbols
Values
Units
PD steady-state error
ess,pd
  
deg
Measured PD steady-state error
ess,meas,pd
  
deg
PID steady-state error
ess,pid
  
kg.m2
Measured PID steady-state error
ess,meas,pid
  
N.m.s./rad
Desired peak time
tp
1.0
s
Desired Percentage Overshoot
PO
20
%
Desired pole location
p0
1.0
rad/s
Natural frequency
Wn
  
rad/s
Damping ratio
ζ
  
N.m/rad
Proportional gain
kp
  
A/rad
Integarl gain
ki
  
A/(rad.s)
Derivative gain
kd
  
A.s/rad
Measured peak time
tp
  
s
Measured Percentage Overshoot
PO
  
%
 

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