MECHATRONICS CONTROL SYSTEM UNIT II

Transcription

1 MECHATRONICS UNIT II CONTROL SYSTEM Prepared By Prof. Shinde Vishal Vasant Dept. of Mechanical Engg. NDMVP S Karmaveer Baburao Thakare College of Engg. Nashik Contact No E mail:- nilvasant22@gmail.com PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

2 Syllabus Block Diagram Representation Open and Closed loop control system, Identification of key elements of mechatronics systems and represent into block diagram (Electro-Mechanical Systems), Concept of transfer function, Block diagram reduction principles, Applications of mechatronics systems:- Household, Automotive, Shop floor, Industrial.

3 Control A Control system performs following functions For particular input the system output can be controlled to a desired particular value. If some conditions are satisfied it can give a particular sequence of events as output corresponding to given input Actual Response Desired Response

4 Open Loop Control Output is dependent on input but controlling action is totally independent of the changes in output, is an Open Loop Control System. No feedback is used, so the controller must independently determine what signal to send to the actuator. Input Control Law u Plant Output Plant = Mathematical model of Input Amplifier + Actuator + Physical System Input = Reference / Desired Input or Set Point Input Output = Measured Output PROF. V.V.SHINDE NDMVP'S Control KBT Law COE = Mathematical NASHIK model of the Controller 19/01/2016

5 Examples of Open Loop Control

6 Advantages and Dis-advantages of Open Loop Control Advantages: Simple in construction Low cost Convenient to implement when output is difficult to measure Disadvantages: The controller never actually knows if the actuator did what it was supposed to do, i.e. it is inaccurate Unable to sense the environmental changes or disturbances

7 Close loop control system PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

8 In a closed-loop control system, the actual value of the parameter being controlled is compared to the desired value. The difference in these values is known as the error. the desired value is known as the reference signal, or set point. This is compared to the signal from the measurement device, known as the feedback signal. The difference between the feedback signal and the reference signal is known as the error signal. The error signal is then modified so that it can adjust the performance of the system. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

9 Examples of Closed Loop Control

10 Examples of Automatic Closed Loop Control

11 Advantages and Dis-advantages of Closed Loop Control Advantages: Accurate, since the controller modifies and manipulates the actuating signal such that the error in the system will be zero. Self-correcting Senses the environmental changes, and disturbances in the system. Disadvantages: Complicated to design Costly Instable, since due to feedback, system tries to correct the error.

12 Key Elements in Mechatronic System

13 Key Elements in Mechatronic System: Example of Electro- Mechanical System

14 Transfer Function Models Why TF? Because it is easier / better to assess some things using classical techniques, such as gain and phase margin. How to determine TF? Derive the overning Differential Equation Assume I.C=Zero and Take Laplace transform of output Take Laplace transform of input Transfer function = L (output) / L (input)

15 Translational Mechanical Example 1 F y M mass/spring/dam system k d F 1/m 1/s 1/s

16 Translational Mechanical Example 1 Equation of motion (EOM) my dy ky f Assuming I.C 0 and taking Laplace of both sides ms 2 y s dsy s ky s f s T.F Output Input y f s s ms 2 1 ds k

17 Introduction Block diagram is a shorthand, graphical representation of a physical system, illustrating the functional relationships among its components. OR A Block Diagram is a shorthand pictorial representation of the cause-and-effect relationship of a system. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

18 The simplest form of the block diagram is the single block, with one input and one output. The interior of the rectangle representing the block usually contains a description of or the name of the element, or the symbol for the mathematical operation to be performed on the input to yield the output. The arrows represent the direction of information or signal flow. x d dt y PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

19 The operations of addition and subtraction have a special representation. The block becomes a small circle, called a summing point, with the appropriate plus or minus sign associated with the arrows entering the circle. Any number of inputs may enter a summing point. The output is the algebraic sum of the inputs. Some books put a cross in the circle. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

20 Components of a Block Diagram for a Linear Time Invariant System System components are alternatively called elements of the system. Block diagram has four components: Signals System/ block Summing junction Pick-off/ Take-off point PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

21 PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

22 In order to have the same signal or variable be an input to more than one block or summing point, a takeoff point is used. Distributes the input signal, undiminished, to several output points. This permits the signal to proceed unaltered along several different paths to several destinations. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

23 Block Diagram: Feedback Closed loop TF Y R s s 1 s s H s Closed loop TF Y R s s s 1 s H s

24 Reduction techniques 1. Combining blocks in cascade or in parallel Moving a summing point behind a block

25 3. Moving a summing point ahead of a block 1 4. Moving a pickoff point behind a block 1 5. Moving a pickoff point ahead of a block

26 6. Eliminating a feedback loop H 1 H 1 H 1 7. Swap with two neighboring summing points A B B A

27 Reduction of Complicated Block Diagrams: PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

28 Example 1

29 Example 1

30 Example 2

31 Example 2

32 Example 3

33 Example 3

34 Example 4

35 Example-5 Simplify the Block Diagram. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

36 Example-5: Continue. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

37 Example-6 Reduce the Block Diagram. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

38 Example-6: Continue. PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

39 Example-7 Reduce the Block Diagram. H 2 R + C H 1 PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

40 Example-7: R + C H H 1 PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

41 Example-7: R + C H 2 1 H 1 PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

42 Example-7: R + H C H 1 PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

43 Example-7: H 2 1 R + _ + _ 1 H C PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

44 Example-7: H 2 1 R + _ + _ H C PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

45 Example-7: R + _ H H C PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

46 Example-7: R H H C PROF. V.V.SHINDE NDMVP'S KBT COE NASHIK 19/01/2016

47 Applications of Mechatronic System Household Refrigerator Washing m/c Microwave Automotive Fuel injection system Power steering Air conditioner Shop floor Tool monitoring system Automated guided vehicle Conveyor system Bottle filing plant.

48 Fuel Injection

49 Electric Power Steering