# A the difference between a desired set

A proportional–integral–derivativecontroller (PID controller or three term controller) is a controlloop feedback mechanism widely used in industrial control systems and a variety of other applicationsrequiring continuously modulated control.

A PID controller continuously calculates an errorvalue   as the difference between adesired set point (SP) and a measured process variable (PV). It applies acorrection based on proportional, integral, and derivative terms (denoted P, I,and D respectively) which give the controller its name. In practical terms it automatically appliesaccurate and responsive correction to a control function. An everyday exampleis the cruise control on a road vehicle; where externalinfluences such as gradients would cause speed changes, and the driver has theability to alter the desired set speed.

We Will Write a Custom Essay Specifically
For You For Only \$13.90/page!

order now

The PID algorithm restores the actualspeed to the desired speed in the optimum way, without delay or overshoot, bycontrolling the power output of the vehicle’s engine.1.1      Overview:Proportional-Integral-Derivative(PID) control is the most common control algorithm used in industry and hasbeen universally accepted in industrial control. The popularity of PIDcontrollers can be attributed partly to their robust performance in a widerange of operating conditions and partly to their functional simplicity, whichallows engineers to operate them in a simple, straightforward manner Asthe name suggests, PID algorithm consists of three basic coefficients;proportional, integral and derivative which are varied to get optimal response. 1.

2       Project Idea:The main idea ofthis project is to control the speed of motor using PID controller. The speed controlof a motor is frequently used in industrial applications, robotics, homeappliances, etc. In this report, we have implemented a DC motor speed controlsystem.

The idea of a speed control system is to maintain the speed of themotor at the desired value under various conditions. DC motor is a nonlineardevice and its speed varies due to change in load demand, disturbancesetc.  PID controller algorithm is implemented whichis a popular controller in industries.1.

3       Figure 1: Block Diagram Purpose of theProject:The primary motivation behind thisundertaking is to control the DC engine by utilizing the three control terms ofrelative, fundamental and subsidiary which impact the controller yield to applyexact and ideal control. The DC engine has been prevalent in the businesscontrol zone for quite a while, in light of the fact that they have numerousgreat qualities. It is broadly utilized as a part of speed control frameworkswhich require high control necessities, for example, moving plant, twofoldhulled tanker, high accuracy computerized instruments and so forth. 1.

4       Project Specifications:The speed controlsystem was implemented for a Permanent Magnet DC Motor (PMDC). The PMDCconsists of rotor or armature and a stator, which is a permanent magnet. Thereare two ways of speed control for a DC motor·        Field Control:   In this method, the field current or currentthrough stator is varied to control the speed of the motor.·        Armature Control:  In this method, the armature voltage isvaried to control the speed of the motor. DCMotor Specifications:1.

12V Permanent Magnet DC Motor2.       Rated current: 200mA at no load, 290mA at fullload3.       Torque: 50gm-cm4.       Maximum speed: 2500 rpmSpeedMeasurement: Theoptical change is utilized to quantify the speed of engine. It is a LED andphotograph transistor match, which creates beats comparing to engine speed. H21A1optical switch is made by Fairchild semiconductors.

H21A1Specifications:1. If (max) = 50 mA.2. Ic (max) = 20 mA.3.Voltage (rev) = 6 V (max)1.

5      Project PlanFour weeks were given to complete the projectof PID controller. So it was divided  infour section containing four weeks.1.6      ReportOrganizationAfter making this project, report was dividedin 6 chapters.

Chapter one consists of introductory things about our project.Second chapter is about literature of our project like theories based on PIDcontroller .Third chapter is of project design and its implementation.

Fourthis about Tools and techniques used in our project. Fifth one is of Result andevaluation last one that is sixth is about conclusion, references and appendix.   CHAPTER 2LITERATURE REVIEW2.1.                Background:DCengines are broadly utilized as a part of mechanical applications, robotcontrollers and home apparatuses, in light of their high unwavering quality,adaptability and minimal effort, where speed and position control of engine arerequired. This task manages the execution assessment of various sorts ofordinary controllers and savvy controller actualized with an unmistakable goalto control the speed of independently energized DC engine.

PIDcontrollers are generally utilized for engine control applications due to theirbasic structures and intuitionally intelligible control calculations.Controller parameters are for the most part tuned utilizing Ziegler-Nicholsrecurrence reaction technique. Ziegler-Nichols recurrence reaction strategy istypically used to modify the parameters of the PID controllers. Be that as itmay, it is expected to get the framework into the swaying mode to understandthe tuning strategy.

Be that as it may, it’s not generally conceivable to getthe majority of the mechanical plants into swaying. Inprocess control, display based control frameworks are essentially used to getthe coveted set focuses and reject little outer unsettling influences. Theinside model control (IMC) outline depends on the way that control frameworkcontains some portrayal of the procedure to be controlled and a flawlesscontrol can be accomplished.2.2.

Related TechnologiesOptimalDesign of PID Controller for the Speed Control of DC Motor by Using Metheuristic Techniques:In this work, a PID controller design for speedcontrol of DC motor is presented. In the first place, the outline throughtraditional systems like Zeigler-Nichols and Cohen-Coon strategies is displayedfor building up a standard. At that point, six metaheuristic improvementcalculations are utilized to locate the most ideal parameters of PID controllersubjected to minimization of a cost work and among these three of the half andhalf procedures are utilized to set up the predominance of crossover metheuristic methods over the others.2.

3.                Related Projects:Analogue ElectronicControllers:Electronicsimple PID control circles were regularly found inside more intricateelectronic frameworks, for instance, the head situating of a plate drive, thepower molding of a power supply, or even the development recognition circuit ofa cutting edge seismometer. Discrete electronic simple controllers have been toa great extent supplanted by advanced controllers utilizing microcontrollers orFPGAs, to execute PID calculations. In any case, discrete simple PIDcontrollers are as yet utilized as a part of specialty applications requiringhigh-transmission capacity and low-commotion execution, for example,laser-diode controllers. 2.

4.                 Limitations of Existing Work:PID controllers are material to manycontrol issues, and regularly perform palatably with no upgrades or just coarsetuning, they can perform inadequately in a few applications, and don’t when allis said in done give ideal control. The essential trouble with PID control isthat it is an input control framework, with consistent parameters, and noimmediate information of the procedure, and along these lines general executionis responsive and a trade off. While PID control is the best controller in aneyewitness without a model of the procedure, better execution can be acquiredby plainly displaying the performing artist of the procedure without fallingback on a spectator. PID controllers, when utilized alone,can give poor execution when the PID circle increases must be lessened with thegoal that the control framework does not overshoot, waver or chase about thecontrol set point esteem. They likewise experience issues within the sight ofnon-linearities, may exchange off direction versus reaction time, don’t respondto changing procedure conduct.

2.5.                Problem Statement:Theproblem statement is that development in the varying assortment and powerestimations of semiconductors has incited quick enhancements of basic controldevices for DC. Nowadays, manual controller is similarly not helpful in thedevelopment time. Operation cost as for controller got thought from mechanicalfield.

Remembering the true objective to limit cost and time, making acontroller in light of PC since it is flexible proposed. The customer canscreen it’s system at certain place without need to heading off to the plant(machine) especially in mechanical execution. From that, the work can bediminished and spare with PC which is more correct and tried and true. Thebasic electronic devices can be arranged using power electronic control deviceto make a speed controller structure. This has driven the authorities toconsider the framework and usage of a power electronic control contraption to aDC engine. The adaptable PID controller is planned to the point that it can beused to beat the issue in industry get a kick out of the opportunity to avoidmachine hurts and to avoid direct rising time and high overshoot.

2.6.                Summary:Thisproject is made to control the speed of DC motor by using a PID controller. Althougha PID controller has three control terms, some applications use only one or twoterms to provide the appropriate control. This is achieved by setting theunused parameters to zero, and is called a PI, PD, P or I controller in theabsence of the other control actions.

PI controllers are fairly common, sincederivative action is sensitive to measurement noise, whereas the absence of anintegral term may prevent the system from reaching its target value.Chapter3 PROJECT DESIGN AND IMPLEMENTATIONThis project was about to control the speedof DC motor using PID controller. To control the speed ofDC motor using PID four circuits are used, the first one is the subtractor,PID, Encoder (motor driver) and FVC (Frequency to voltage controller) circuit.

3.1.       Proposed Design MethodologyAt first we have given the variablereference and used subtractor to generate error.

Then there was a circuit ofPID and after PID there was an adder which added up the three circuits P, I andD. After adder there was a motor driver and motor encoder and at last there wasa Frequency to Voltage converter. As the name indicates it converts thefrequency into voltage.

Analysis Procedure3.2.       Implementation ProcedureFirstly, block diagram was made and then that block diagram was designedon proteus. Below given figure was used to complete the project.      3.

3.       Design of the Project Hardware  ·        Schematic diagram of the circuit is:        Figure 2 : Schematic Diagram  Simulation          Figure 3: Simulation  3.4.

Details of Final Working Prototype  With the utilization of minimal effort basicON-OFF controller just two control states are conceivable, as completely ON orcompletely OFF. It is utilized for restricted control application where thesetwo control states are sufficient for control objective. However waveringnature of this control restrains its use and subsequently it is being supplantedby PID controllers. PID controller keeps up the yield with theend goal that there is zero mistake between process variable and setpoint/wanted yield by shut circle operations.

PID utilizes three fundamentalcontrol practices that are clarified beneath.3.4.1.

Figure 4: Response of P control  P-Controller:      Output of Proportional or P- controller is directly proportional to currenterror e (t). It compares desired or set point with actual value or feedbackprocess value. The resulting error is multiplied with proportional constant toget the output. The controller output is zero if the error value is zero.

3.4.2.                      P-Controller Response Figure 5: Response of PI Controller This controller requires biasing or manualreset when used alone.

This is because it never reaches the steady statecondition. It provides stable operation but always maintains the steady stateerror.  Speed of the response is increased when the proportional constant Kc increase3.4.

3.                      Integral Controller       3.4.

4.                      PI controllerDue to limitation ofp-controller where there always exists an offset between the process variableand set point, I-controller is needed, which provides necessary action toeliminate the steady state error.  It integrates the error over a periodof time until error value reaches to zero. It holds the value to final controldevice at which error becomes zero.

Integral control decreasesits output when negative error takes place. It limits the speed of response andaffects stability of the system. Speed of the response is increased bydecreasing integral gain Ki. Figure 6 : Graph of proportional gain Whileusing the PI controller, I-controller output is limited to somewhat range toovercome the integral wind up conditions where integral output goes onincreasing even at zero error state, due to nonlinearities in the plant.                                                    3.4.

5.                       Derivative-ControllerIntegral -controller doesn’t have the capability to predict the futurebehaviour of error. So, it reacts normally once the set point is changed.D-controller overcomes this problem by anticipating future behaviour of theerror. Its output depends on rate of change of error with respect to time,multiplied by derivative constant.

It gives the kick start for the outputthereby increasing system At last, we got the desired system by combining the above mentionedcircuits. Different manufactures design different PID algorithms. Figure 7 : Graph of derivative control      3.5.

SummaryInthe end we concluded that speed of DC motor can be controlled by PIDcontroller. So, firstly by changing P-factor or proportional factor it can beseen that how overshoot of thesignal can be changed and rise time of the signal got changed.         Chapter 4 TOOLS AND TECHNIQUESTools and techniques ofthis project are discussed in this project.

4.1 Hardware Tools Fourcircuits are used in this project i.e. subtractor, PID, encoder and FVC.

1.      Resistors2.      Capacitors3.      DCmotor4.      Photodiode5.

Transistor6.      Switch7.      Feedback8.      Variableresistor 9.

ICs10.  Connectors11.  PCBsheet12.  Solderingmachine13.  Wires14.

Breadboard  4.1.                    Resistors: Resistoris a passive device used to resist the flow of current. Its schematic symbol is   Resistorsare found in different values according to their color coding.

Figure 8: Resistors 4.2.                     Capacitor: Figure 9: Capacitors Capacitoris a device used to store electric charges.

It consists of pairs of conductionseparated by an insulator.  Capacitorsare used to smooth the wave or to remove noises from the wave.  4.3.                    DC MotorA DC motor is anelectrical machine that converts electrical energy into mechanical energy.

Themost common types rely on the forces produced by magnetic fields. Nearly alltypes of DC motors have some internal mechanism, either electromechanical orelectronic, to periodically change the direction of current flow in part of themotor. 4.

4.                    Photo Diode:  A photodiode isa semiconductor device that converts light into an electrical current.Generation of current is due to absorption of photon in the photodiode. Photodiodes have large orsmall surface area with optical fiber in it.

Figure 10: Photo Diode    4.5.                     Transistor:Asemiconductor device which is used to amplify or switch electronic signals andelectrical power is called transistor. It is composed of semiconductor materialusually with at least three terminals for connection to an external circuit.The transistor that used in this project is BC337.

Sample of a transistor isgiven below:    Figure 11: Transistor 4.6.                    Integrated Circuit:An integratedcircuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits onone small flat piece (or “chip”) of semiconductor material, normallysilicon.

In  this  project LM358 is used. It has 8 pins. It hastwo operational amplifiers. These operational amplifiers are used asproportional, integral and derivative.

Frequency to voltage controller is alsomade from these IC’s.     4.7.                    Software We have used Proteus 8.0 to simulate the design. InProteus circuits can be designed, simulate. It is a very useful software tomake PCB layout of circuit.  Chapter 5Projects Results and EvaluationThisproject consists of different parts i.e. Frequency to voltage converter,Subtractor, Adder, Motor Driver, Reference signal. After completing thisproject, this project is able to control the speed of DC motor.5.1.        Presentation of Findings:5.1.1. Proportional Control:The proportional term produces an output value that is proportional to thecurrent error value. The proportional response can be adjusted by multiplyingthe error by a constant Kp, called the proportional gainconstant.  {displaystyle P_{ ext{out}}=K_{ ext{p}}e(t).}       5.1.2.  Integral Control:The contribution from the integral term isproportional to both the magnitude of the error and the duration of the error.The integral in a PID controller is the sum of theinstantaneous error over time and gives the accumulated offset that should havebeen corrected previously. The accumulated error is then multiplied by theintegral gain (Ki) and added to the controller output.       5.1.3.  Derivative Control:A derivative term does not consider the error (meaning itcannot bring it to zero: a pure D controller cannot bring the system to its setpoint), but the rate of change of error, trying to bring this rate to zero. Itaims at flattening the error trajectory into a horizontal line, damping theforce applied, and so reduces overshoot (error on the other side because toogreat applied force). Applying too much impetus when the error is small and isreducing will lead to overshoot. After overshooting, if the controller were toapply a large correction in the opposite direction and repeatedly overshoot thedesired position, the output would oscillate around the set point either a constant, growing, ordecaying sinusoid. If the amplitude of the oscillationsincreases with time, the system is unstable. If they decrease, the system isstable. If the oscillations remain at a constant magnitude, the system is marginallystable.5.2.        Hardware Results: Figure 12 : Hardware Project          5.3.        Limitations:This project, when used alone, can give poorperformance when the PID loop gains must be reduced so that the control systemdoes not overshoot, oscillate or hunt about thecontrol setpoint value. They also have difficulties in the presence ofnon-linearities, may trade-off regulation versus response time, do not react tochanging process behavior (say, the process changes after it has warmed up),and have lag in responding to large disturbances.5.3.1. Linearity:Another problem faced with thisproject is that they are linear, and in particular symmetric. Thus, performanceof PID controllers in non-linear systems is variable.5.3.2. Noise in Derivative:A problem with thederivative term is that it amplifies higher frequency measurement orprocess noise that can cause large amounts of change in the output.It is often helpful to filter the measurements with a low-pass filter in order to remove higher-frequency noisecomponents.5.4.        Recommendations and Future Work:·        It is recommended a high enough samplingrate, measurement precision, and measurement accuracy should installed toachieve adequate control performance.·        New method for improvement of PIDcontroller should introduced to increase the degree of freedom by using fractional order. ·        The order of the integrator anddifferentiator should add to increase flexibility to the controller. This project is mainlyconsists of three parts which has performed their work efficiently.The goal of project; tocontrol the speed of DC motor is achieved.  CHAPTER 6:ConclusionsIt is concluded thatPID controller can control the speed of DC motor. PID controllers are commonly used toregulate the time-domain behavior of many differenttypes of dynamic plants. These controllers are extremely popular becausethey can usually provide good closed-loop responsecharacteristics, can be tuned using relatively simpledesign rules, and are easy to construct using either analogor digital components.

x

Hi!
I'm Gerard!

Would you like to get a custom essay? How about receiving a customized one?

Check it out