Question

6. A position control system is being designed, for use as part of an autonomous warehouse storage facility. The designers have modelled the system with the block diagram shown in Figure Q6. The unknown transfer function G(jw)represents an actuator within the system that has not yet been modelled. The"Process' block represents the dynamics of the storage pallet being moved. A set of experimental tests has been performed to obtain the magnitude |G(jw)|for different values of w. The results are shown in Figure Q6a. The designers have used this data to identify a new model of G(jw) in the form: G_{n e w}(j \omega)=\frac{K_{a}}{1+\frac{j \omega}{\omega_{1}}} a) Use Figure Q6a to obtain values for Ka and wi. Show your working and any necessary sketch diagrams in your handwritten script. Do not show your working on Figure Q6a as this will not be submitted with your examination script. b) Briefly describe how this data would be obtained experimentally. Your answer should mention the hardware involved, as well as any required signal processing procedures. c) Describe how the resulting system model could be used to determine the system stability, using the Bode diagram asymptotes and the gain and phase margin approach. You do not need to assemble the gain and phase Bode diagrams on an accurate graph, but your answer should include sketch diagrams to describe your approach. d) Use your knowledge of the Bode diagram asymptotes to discuss whether the bandwidth of the actuator impacts on the control system performance.

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