Dynamic and control subjest Assignment Example | Topics and Well Written Essays - 2500 words

Dynamic and operate subjest - Assignment ExampleController controls the system behaviour by providing the necessary excitation. Setpoint is the desired result. Output is the actual result. PID restrainer may be written in the equation form as = + + (1) In this equation, all the symbols beat the meanings explained earlier. Coming to the explanation in common words, with reference to Figure 1, we want the emergeput Y of a process to be equal to or as close to the setpoint R as possible. Since the real systems argon not ideal systems, usually some kind of control system is required to achieve this objective. In a PID controller, the output Y is compared with the setpoint R, the error e is calculated to be equal to R minus Y. Then the controller (a PID controller in this case) calculates u(t) from equation (1). This u(t) is an excitation signal to be passed to the process, with the objective of driving the output Y as close to the setpoint R as possible. For example, let us sequeste r that we are required to control the temperature of the pee sexual climax out from a hip-hop. Let us model that we want the temperature of the pee to be just about 50 degree centigrade always. But let us absorb that water is supplied to this tap by two separate water foods. Let us need that unmatched of the water feed is always at around 30?C (cold water feed). Also, let us assume that the other water feed is always at around 70?C ( acrid water feed). We can see that to get the water from the tap at 50?C, we need to mix around 50% water from the hot water feed with the remaining 50% water from the cold water feed. This can be achieved by making the valve corresponding to the hot water feed 50% have (i.e., 50% closed) and at the same time, making the valve corresponding to the cold water feed 50% render (i.e., 50% closed). But, in a real system exchangeable this, one comes across several uncertainties like the temperature losses during the flow in the pipes due to radi ation therapy etc., which cannot be determined for certain since in this case, the radiation depends on the atmospheric temperature (or room temperature) also. Hence, when the valve corresponding to the hot water feed is 50% open air and at the same time when the valve corresponding to the cold water feed is 50% open, the temperature of the water coming out from the tap may not be exactly equal to 50%. Let us assume that this temperature is 45?C. Now, in this problem, the setpoint R is 50?C while the output Y is 45?C. Now, consort to Figure 1, R-Y= 5 ?C is calculated. This is the error e which is an input to the controller. Then the controller calculates u(t) from Equation (1), this u(t) is in fact a signal which controls the valves. In this case, u(t) would instruct the valve corresponding to the hot water feed to open more than 50% (exact percentage would be known from u(t)). Opening the valve corresponding to the hot water feed x% would automatically mean opening the valve corre sponding to the cold water feed (100-x)%. This ensures that the flow from the hot water feed is more than the flow from the cold water feed, which in turn forces the temperature of the water coming from the tap to go to 50?C. This way, the controller strives to make the temperature of the water coming out from the tap to be 50?C, and for a proper selection of the values for Kp, Ki and Kd, the controller usually performs its task satisfactorily. If the temperature of the tap water goes to 55?C for example, the error would