- #1
David J
Gold Member
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Homework Statement
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The proportional control system of figure 3(a) (attachment 235263) has an input, ##\theta_{1}##, of 10 units. The uncontrolled input, ##\theta_{2}##, has a value of 50 units, prior to a step change down to 40 units. The result of this disturbance upon the output, ##\theta_{o}## is shown in figure 3(b) (attachment 235264)
(a) Calculate the change in offset in the output produced by the step change
(b) Draw a modified block diagram to show how the offset could be minimised by the inclusion of another control action. Also, show by means of a sketch how the modification might be expected to affect the output response.
(c) Show, by drawing a modified block diagram, how the magnitude of the disturbance could be minimised by the inclusion of a third type of control action
2. Homework Equations
##\theta_{0}=\frac{\theta_{2} +G\theta_{1}}{1+G}##
The Attempt at a Solution
(a)
[/B]
Prior to the step change
##\theta_{0}## = ##\frac{50 + (9*10)}{1+G}##
so ##\theta_{0}## = ##\frac{140}{10}##=## 14 m^{3 h-1}##
After the step change
##\theta_{0}## = ##\frac{40 + (9*10)}{1+G}##
so ##\theta_{0}## = ##\frac{130}{10}##=## 13 m^{3 h-1}##
So in the first instance would I be correct in saying that the change in offset in the output as a result of the step change will be ## 1 m^{3 h-1}## ?
I attached some notes, (pages 16 and 17) which I think are in relation to this question