ISVR6139 – Active Control of Sound and Vibration

发布时间：2024-05-11

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ISVR6139 – Active Control of Sound and Vibration

Final Assignment

Part 1: Lab Exercise

1. Plot the frequency response (magnitude and phase) of the open-loop system defined by eq. 4, with the mass, stiffness and damping parameters: m = 5 kg, k = 2.2× 106 N/m, and c = 20 Ns/m. From the resulting plot, assess the resonance frequency of the system.

[5 marks]

2. Plot the open-loop response, G jφ H j φ , of the system as both a Nyquist plot and a Bode plot and assess the stability of the controller for various settings of ga, gv

and gd .

[10 marks]

3. Plot the closed-loop response given by equation 7 for different feedback gain

settings and explain how displacement, velocity and acceleration feedback control influence the SDOF dynamic properties.

[10 marks]

4. Plot the velocity and displacement response of the SDOF system over time to an

initial condition of 0 primary input force and an initial displacement of 0. 1 m.

Describe the key features of these responses.

[10 marks]

5. Calculate the modified state-space representation for the system with displacement, velocity or acceleration feedback control.

[5 marks]

6. Using the modified state-space representation, explore the effect of changing the

displacement, velocity and acceleration feedback gain settings individually and plot the results. In particular, you should relate the time-domain responses to the observations you made regarding the effects of control in the frequency domain.

[10 marks]

7. Plot the eigenvalues of the open-loop matrix, A, and those of the corresponding closed-loop matrix. Explain how the eigenvalues vary as the three gains are modified.

[10 marks]

8. Plot the time-domain response of the system with and without control (open and

closed-loop) when it is persistently excited by a sine wave. Comment on the open loop response and the closed-loop response for the different feedback control

strategies.

[10 marks]

Part 2: Short Essay

This part of the assessment is worth 30% of the assignment mark. You should write a summary of an application or novel development in the field of active control of your choice. This should be around 1000-words, or approximately 2 pages (The strict limit is on the total page count for the assignment). Credit will be given for the originality of your choice, for example, applications already covered in the course will receive minimum credit. You should expect to spend some time researching different topics and choosing a topic to write about. For example, you might summarise a new algorithm or application that has been reported in a research article, or describe an active control system that you might find described in a patent. You do not necessarily need to limit yourself to noise and vibration control applications, but you should be able to make general links to the topics covered by the course and apply your knowledge to offer some engineering interpretation (feedforward control, feedback control, stability, robustness, single channel, multichannel, error signals, reference signals etc.). You are encouraged to use graphics to help support your writing, but you must make sure that you provide suitable references to the source of any material you use. Marks will be awarded as follows:

a) Introduction and description of the application of active control [10 marks]

b) Technical contents [10 marks]

c) Discussion [5 marks]

d) Referencing and use of graphics [5 marks]

[Total: 30 marks]