Control System Design

A brief introduction to designing consideration during a control system and implementation in mechatronics system.

1. INTRODUCTION TO CONTROL SYSTEM DESIGN PRESENTED BY:- HITESH SHARMA HOZEFA HUSSAIN JAI RAWAL JASPREET SINGH JATIN VIJAY JITENDRA LAKHARA KAILASH SHARMA KAPIL KULHAR KARTIK KHANDELWAL PRESENTED TO:- MR. HIMANSHU SINGH RATHORE DEPT. OF MECHANICAL ENGINEERING, SKIT

2. CONTROL SYSTEMS A  CONTROL SYSTEM  IS A DEVICE, OR SET OF DEVICES, THAT MANAGES, COMMANDS, DIRECTS OR REGULATES THE BEHAVIOUR OF OTHER DEVICES OR SYSTEMS.

3. TYPES OF CONTROL SYSTEM

4. TYPES OF CONTROL SYSTEM DESIGN

5. Control System Devices

6. INPUT CONTROL DEVICES Input devices are used to sense a condition, detect movement or position, indicate a limit or set point has been reached, sense intervention by an operator, detect an alarm, etc. Typical input devices may include limit switches, photoelectric sensors, pushbuttons, proximity sensors, an operator interface, etc.

7. OUTPUT CONTROL DEVICES Output devices are used to control actions such as motion, start/stop of equipment like conveyors and pumps, on/off control of valves, operator alerts/prompts, status indications, etc. Typical output devices include relays, motor starters, pilot lights, operator interface graphics and numeric display, etc.

8. PROCESSING CONTROL DEVICE All control systems can typically be defined as having inputs, outputs and some form of decision making going on in between so that the outputs are controlled based on the status of the inputs. This brings us to our third category, the "decision making" element. The microprocessor used on the motherboard, along with its memory, the operating system, and the application program would serve as the decision making element. As a matter of fact, PCs are used in some automated control systems as the decision making element, together with industrial input and output (I/O) modules

9. Purpose of Control Systems Power Amplification (Gain) Positioning of a large radar antenna by low-power rotation of a knob Remote Control Robotic arm used to pick up radioactive materials Convenience of Input Form Changing room temperature by thermostat position Compensation for Disturbances Controlling antenna position in the presence of large wind disturbance torque

10. Control System Open-loop control system – operates without the feedback loop Simpler and less expensive Risk that the actuator will not have the intended effect Closed-loop (feedback) control system – a system in which the output variable is compared with an input parameter, and any difference between the two is used to drive the output into agreement with the input

11. Feedback Feedback is a key tool that can be used to modify the behavior of a system. This behavior altering effect of feedback is a key mechanism that control engineers exploit deliberately to achieve the objective of acting on a system to ensure that the desired performance specifications are achieved.

12. Control System Classification Open-Loop Control System Missile Launcher System

13. Control System Classification Closed-Loop Feedback Control System Missile Launcher System

14. Open loop system

15. Closed loop system

16. Open loo p system Dynamic Response Open-Loop Control System (No feedback)

17. Closed loop System Response of a position control system showing effect of high and low controller gain on the output response

18. Example Control System? (1) Temperature Control System ( Heater or Air Condition )

19. Example Control System? (2) Vehicle Control System

20. Example Control System? (3) Autopilot Control System

21. ADAPTIVE CONTROL SYSTEM DESIGN

22. Adaptive control is the control method used by a controller which must adapt to a controlled system with parameters which vary, or are initially uncertain . For example, as an aircraft flies, its mass will slowly decrease as a result of fuel consumption; a control law is needed that adapts itself to such changing conditions. . INTRODUCTION TO ADAPTIVE CONTROL

23. Basic concepts: Why Adaptive Control ? dealing with complex systems that have unpredictable parameter deviations and uncertainties maintain consistent performance of a system in the presence of uncertainty and variations in plant parameters Adaptive control is superior to robust control in dealing with uncertainties in constant or slow-varying parameter . Estimate uncertain plant / controller parameters on-line, while using measured system signals

24. Adaptive cruise control is similar to conventional cruise control in that it maintains the vehicle's pre-set speed. However, unlike conventional cruise control, this new system can automatically adjust speed in order to maintain a proper distance between vehicles in the same lane. This is achieved through a  radar headway sensor ,  digital signal processor  and  longitudinal controller . If the lead vehicle slows down, or if another object is detected, the system sends a signal to the engine or braking system to decelerate. Then, when the road is clear, the system will re-accelerate the vehicle back to the set speed. EXAMPLE OF ADAPTIVE CONTROL IN AUTOMOBILE ADVANTAGE 1.Provide relief to the driver in heavy traffic situations. 2.Improve safety of vechile and driver. LIMITATIONS: 1.Very expansive system so used in expansive cars ie.BMW,AUDI .

25. NON LINEAR ADAPTIVE CONTROL SYSTEM

26. Contents Introduction MRAC system Conditions Design of nonlinear contro l system Mathematical calculations

27. Introduction Principle of homogeneity or S uperposition principle Example: Thermostat-controlled heating system

28. MRAC (Model reference adaptive control) Fig. Design of optimized PI controller Reference model -specifies output of reference input Controller - contains adjustable parameters Adjustment mechanism - update the adjustable parameters within the controller

29. Conditions The unknown parameters with in the nonlinear plant are linearly parameterized The complete state vector is measured When the unknown parameters are assumed known, the control input can cancel all the non linarites in a feedback linearization sense and any remaining internal dynamics should be stable. Solve by MRAC method.

30. Design Of Non Linear Adaptive Control System Sketch the System layout. Calculate output for reference input. Compare the this output with reference output and find error. 4. A nd applies this error signal to the system to bring the output closer to the reference.

31. Mathematical Techniques To Solve Non Linear System Limit cycle  theory Poincaré maps Lyapunov stability theory Describing functions.

32. Lyapunov Stability Theory Lyapunov functions  are scalar functions that are used to prove the stability of an equilibrium of a Differential Equation. Informally, a Lyapunov function is a function that takes positive values everywhere and decreases (or is non-increasing) along  every  trajectory of the Differential Equation.

33. Mathematical Definition Of A Lyapunov Function Let V : R n Be a continuous scalar function. then V is a lyapunov function if it’s a locally positive-definite function i.e. V(0)=0 V(x)>0 where x is real number R

34. Definition Of The Equilibrium Point Of A System let y: R n ġ=y(g) Value of g at which function ġ becomes zero is called equilibrium point R

35. Basic Lyapunov Theorems For Systems

36. Basic Lyapunov Theorems For Systems(Contd.) If the Lyapunov-candidate-function V is locally positive definite and the time derivative of the Lyapunov-candidate-function is locally negative semi definite then the equilibrium is proven to be  stable . If the Lyapunov-candidate-function  V is locally positive definite and the time derivative of the Lyapunov-candidate-function is locally negative definite then the equilibrium is proven to be  locally asymptotically stable . If the Lyapunov-candidate-function V is globally positive definite, radially unbounded  and the time derivative of the Lyapunov-candidate-function is globally negative definite then the equilibrium is proven to be  globally asymptotically stable.

37. Applications of control system design Rotary indexer Application type: indexing conveyor Motion: rotary Labelling machine Application type: following Motion: linear Surface grinding machine Application type: tool feed Motion: Linear

38. Thank you