TITLE Computer aided design OBJECTIVE yTo analyze and to design a control system using the PERISIK program based o n the time domain analysis method. yTo analyze and to design a control system using the PERISIK program based on the frequency domain analysis method. INTRODUCTION Computer Aided Design (CAD) is the use of computers to assist the design process. CAD software, or environments, provides the user with input-tools for the purpose of streamlining design processes; drafting, documentation, and manufacturing processes. Specialized CAD programs exist for various types of design: architectural, engineering, electronics, roadways, and woven fabrics to name a few. CAD programs usually allow a structure to be built up from several re-usable 3-dimensional components, and the components (such as gears) may be able to move in relation to one another. CAD output is often in the form of electronic files for print ormachining operations. It is normally possible to generate engineering drawings to allow the final design to be constructed. Root locus analysis is a g raphical method for examining how the roots o f a system change with variation of a certain system parameter, commonly the gain of a feedback system. It can be used to analyze and design the effect of loop gain upon the system¶s transient response and stability. The graphical of the root locus give us the description of a control system¶s
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 1/14
TITLE
Computer aided design
OBJECTIVE
y To analyze and to design a control system using the PERISIK program based on the time
domain analysis method.
y To analyze and to design a control system using the PERISIK program based on the
frequency domain analysis method.
INTRODUCTION
Computer Aided Design (CAD) is the use of computers to assist the design process. CAD
software, or environments, provides the user with input-tools for the purpose of streamlining
design processes; drafting, documentation, and manufacturing processes. Specialized CAD
programs exist for various types of design: architectural, engineering, electronics, roadways, and
woven fabrics to name a few. CAD programs usually allow a structure to be built up from
several re-usable 3-dimensional components, and the components (such as gears) may be able to
move in relation to one another. CAD output is often in the form of electronic files for print or
machining operations. It is normally possible to generate engineering drawings to allow the final
design to be constructed.
Root locus analysis is a graphical method for examining how the roots of a system
change with variation of a certain system parameter, commonly the gain of a feedback system. It
can be used to analyze and design the effect of loop gain upon the system¶s transient response
and stability. The graphical of the root locus give us the description of a control system¶s
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 2/14
performance that we are looking for and also serve as a powerful quantitative tool that yield
more information then mathematics method.
A Bode plot is a graph of the transfer function of a linear, time-invariant system
versus frequency, plotted with a log-frequency axis, to show the system's frequency response. It
is usually a combination of a Bode magnitude plot, expressing the magnitude of the frequency
response gain, and a Bode phase plot, expressing the frequency response phase shift.
A Nichols plot is a plot used in signal processing in which the logarithm of the magnitude
is plotted against the phase of a frequency response on orthogonal axes. This plot combines the
two types of Bode plot ² magnitude and phase ² on a single graph, with frequency as a
parameter along the curve.
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 3/14
METHOD
EXPERIMENT A
Figure 1
1. Transfer function in figure 1 was simulated using PERISIK program.
2 PERSIK icon was double clicks to access the program.
3. The data of the transfer function was inserted into the PERISIK system.
4. The transfer function was simulated using the program and value was determined
from the result of simulation.
5. Time response plot was simulated to determine the system unity step response.
6. Value K was determined when damping ration is 0.2 and 0.707.
7. Break point, corresponding gain and third pole were determined.
8. Third pole was determined when damping ratio is 0.707.
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 4/14
EXPERIMENT B
Figure 2
Section A
1. The data of the transfer function was inserted into the PERISIK system.
2. The transfer function was simulated using the program.
3. Gain Margin , Phase Margin Bandwidth , Peak Frequency and Peak Magnitude
was determined from the program.
4. Nichols chart and bode plot were sketched.
5. Table 2 was completed by using Nichols chart method.
Section B
1. Steady state error function was obtained when input is a ramp function. was
calculated when K=1.
2. was obtained using PERISIK.
3. The existence of was checked with PERISIK when it is step input.
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 5/14
Section C
1. was calculated in order to have< 0.2 with ramp input.
2. The value was verified using PERISIK.
3. Ramp Response was sketched
4. Table 3 was completed by using Bode Plot technique and Nichols Chart.
RESULT
Experimental (A)
1. T
he value of obtained is 48 while the value obtained manually is 48.
Figure 1: Root locus (using mathlab)
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 6/14
Figure 2: System Unity step response for k=48( using matlab)
Figure 3:Root locus when damping ration = 0.2 (using matlab)
When damping ration is 0.2, gain (k) is 19.54 while the dominant poles is s= -0.41 +1.9j
(using PERISIK)
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 7/14
Figure 4:Root locus when damping ratio=0.707 (using matlab)
When damping ratio is equal to 0.707, the Gain(k) is 4.12 and dominant poles, s=0.77+0.73j
(using PERISIK)
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 8/14
Time Domain Characteristics =0.2 =0.707
1.Rise Time (Tr ) 0.6162 2.55
2. Maximum Overshoot Time (T p) 1.86 4.52
3. Maximum Overshoot (M p) 1.4733 1.0348
4. Settling Time (Ts) 10.11 5.78
Table 1 Time domain characteristic for =0.2 and 0.707
2. The break point is -0.86 and the corresponding gain is 3.08 and the third pole is -4.31
3. The third pole for the system when damping ratio 0.707 is -4.46
8/6/2019 Long Report2
http://slidepdf.com/reader/full/long-report2 9/14
Experimental (B)
Section A
Response Criteria Bode plot Nichols chart Average
1. Gain Margin(db) 29.19 29.64 29.415
2. Phase Margin,(°) 177.37 177.79 177.58
3. Bandwidth , (at-
3dB)
0.37 0.37 0.37
4. Peak
Frequency,(rad/s)
0.01 0.01 0.01
5. Peak Magnitude, 0 0 0
Table 2: Response criteria for Bode plot, Nicholas Chart and their average