Describes the speed control method of DC motor by using the Particle swarm optimization method implemented on a PID controller.

1. SPEED CONTROL OF DC MOTOR
USING CONVENTIONAL AND PSO
TUNED PID CONTROLLER
Presented by,
AJESH BENNY
2/4/20191

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INTRODUCTION
 The speed control of a motor is frequently required in
industrial applications, robotics, home appliances, etc.
 The idea of a speed control system is to maintain the
speed of the motor at the desired value under various
condition. In practice, the DC motor is a nonlinear
device and its speed varies because of change in load
demand, disturbances, etc.
 PID controllers are most commonly used controller in
industrial applications.

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DC MOTOR SPEED CONTROL
SYSTEM
Reference
speed
CONTROLLER DC MOTOR
F/V
CONVERTER
SPEED
SENSOR
+
-
Fig. 1 Dc motor speed control system

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 To measure the motor speed an optical switch
is used. It is a LED and photo transistor pair,
which generates pulses corresponding to
motor speed.
 The pulses from optical switch are given to a F/V
converter. The F/V converter produce a DC
voltage proportional to motor speed.
 The controller acts on the error signal and
generates appropriate control voltage.
Speed Control System contd…

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PID CONTROLLER
 PID controllers are used in more than 95% of
closed-loop industrial processes.
 The PID controllers need of less plant
information than a complete mathematical
model.
 The transfer function of PID controller is:
Or,

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Fig. 2 Basic block diagram of a conventional PID controller
Kp e(t)
Ki ∫ 𝑒( 𝑥) 𝑑𝑥
𝑡
Kd
𝑑𝑒
𝑑𝑡
Plant
Setpoint OutputError
BLOCK DIAGRAM OF PID
CONTROLLER

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SYSTEM RESPONSE WITH PI
& PID CONTROLLER
Fig. 4 Step response of PID controllerFig. 3 PI controller step response

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TUNING OF CONTROLLER
• Tuning is adjustment of control parameters to the
optimum values for the desired control response.
• There are accordingly various methods for loop
tuning, some of them are:
-Manual tuning method,
-Ziegler–Nichols tuning method,
-PID tuning software methods.

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Manual Tuning Method
In manual tuning method, parameters are
adjusted by watching system responses. Kp, Ki, Kd are
changed until desired or required system response is
obtained. Although this method is simple, it should be
used by experienced personal.

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Ziegler–Nichols tuning method
• There are two methodologies:
1) Continuous Cycling Method
2) Damped Oscillation Method
1) Continuous Cycling Method

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Continues cycling method cont…..
• The Controller is first set to operate in P mode.
• set Td=0,Ti=∞.
• Increase the proportional gain to Kp=Kpmax,
till the system just starts oscillating with
constant amplitude continuously.
• The time period of continuous oscillation Tu is
noted.
• The optimum settings are:
Kp = 0.6 Kpmax, Ti =Tu/2, Td =Tu/8

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2) Damped Oscillation Method
• Implemented in the case of discontinuous oscillations.

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• Start with low gain proportional control mode with
Ti=0, Ti=∞.
• The gain increased slowly till a decay ratio(p2/p1)
of 1/4th is obtained in step response in the output.
• note Te.
• Ke be the proportional gain setting for obtaining
1/4th decay ratio.
• The optimum settings are:
Kp=Ke , Ti=Te/6,Td=Te/1.5.
Damped Oscillation method cont…..

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System Response with ZN method
Fig.5 System response with ziegler-nichols method

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Particle Swarm Optimization Technique
(PSO Algorithm)
 Inspired from the nature, social behavior and
dynamic movements with communications of insects, birds
and fish.

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 Particle Swarm Optimization (PSO) technique,
proposed by Kennedy and Eberhart in 1995.
 PSO is a robust stochastic optimization technique
based on the movement and intelligence of
swarms.
PSO Contd…

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Each particle keeps track of its coordinates
in the solution space which are associated
with the best solution (fitness) that has
achieved so far by that particle. This value is
called personal best , pbest.
 Another best value that is tracked by the
PSO is the best value obtained so far by any
particle in the neighborhood of that particle.
This value is called gbest.

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Pi(t)
Xi(t) Gi(t) – Xi(t)
Gi(t)
Xi(t+1)
)
New Velocity,
Vij(t+1)=w Vij(t) + r1C1 [Pij(t) – Xij(t)] + r2C2 [Gij(t) – Xij(t)]
New Position,
Xij(t+1)=Xij(t) + Vij(t + 1)
PSO contd…

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The components of PSO are
Swarm Size, Velocity,
position components and
maximum no of iteration.
This techniques is used to
minimize;
-Maximum Overshoot
-Rise time
-Steady state error
-Settling time
PSO contd…

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The structure of the PID controller
with PSO algorithm
Fig.7 PSO-PID Controller Block diagram

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Response of PSO-PID
Controller
Fig.8 PSO-PID controller response

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COMPARISON
[PI,PID,
ZN,PSO]
PI
RESPONSE
PID
RESPONSE
ZIEGLER
NICHOLS
RESPONSE
PSO algorithm
Rise time (s) 6.01 4.99 2.95 0.0451
Settling time
(s)
34.1 20.4 5.28 0.0849
Peak time (s) 1.19 1.06 1.00 1.00
Overshoot
(%)
19 6.17 0.0446 0
Step
Response
STABLE STABLE STABLE More stable
COMPARISON [PI,PID,Z-N,PSO]

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CONCLUSION
 The conventional controllers however are not
recommended for higher order and complex systems
as they can cause the system to become
unstable.
 Hence, a heuristic approach is required for choice
of the controller parameters which can be provided
with the help of Bio inspired methods such as
Particle swarm Optimization, where we can define
variables in a subjective way.

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1) Luis Brito Palma,Fernando Vieira Coito,Bruno Gomes
Ferreira,Paulo Sousa Gil ,”PSO based on-line optimization for
DC motor speed control”, Compatibility and Power
Electronics(CPE) 9th International conference ©2015 IEEE.
2) Subhojit Malik, Palash Dutta, Sayantan Chakrabarti, Abhishek
Barman,“Parameter Estimation of a PID Controller using
Particle Swarm Optimization Algorithm”, International Journal
of Advanced Research in Computer and Communication
Engineering (IJARCCE) Vol. 3, Issue 3, March 2014.
3) P.M.Meshram, Rohit G. Kanojiya, “Tuning of PID Controller
using ziegler-nichols method for Speed Control of DC
motor”,IEEE international confrence on advanced in
engineering, science and management (ICAESM-2012) march
30,31,2012,.
REFERENCES

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4) Dr.Ch.Chengaiah1, K.Venkateswarlu2, “Comparative Study
on Dc Motor Speed Control Using Various Controllers”
International Journal of Advanced Research in Electrical,
Electronics and Instrumentation Engineering Vol. 3, Issue 1,
January 2014.
5) Zwe-Lee Gaing, A particle Swarm Optimization Approach for
Optimum Design of PID Controller in AVR(Automatic Voltage
Regulator) System, IEEE Transactions on Energy
Conversion, Vol.19, No.2, 384-391, 2004.
6) Anupam Aggrawal, 2Akhilesh Kumar Mishra*, 3Abdul Zeeshan
“Speed Control of DC Motor Using Particle Swarm
Optimization Technique by PSO Tunned PID and FOPID”,
International Journal of Engineering Trends and
Technology (IJETT) – Volume 16 Number 2 – Oct 2014

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