UTeM 29/1/14 UNIVERSITI TEKNIKAL MALAYSIA MELAKAportal.utem.edu.my/iSMPS/ProgRpt/M011310008_1-20152016.pdf · positioning and tracking motion experimental studies. Besides, this study

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA PUSAT PENGAJIAN SISWAZAH

LAPORAN KEMAJUAN (PROGRESS REPORT) SEMESTER .....5........ SESI ........2015/2016........

A. MAKLUMAT PELAJAR / DETAILS OF STUDENT

Nama (Name) : Penganjur (Sponsor) :

VASANTHAN A/L SAKTHI VELU My Brain 15 KPT

No. Matrik (Matric No.): Fakulti (Faculty) :

M011310008 FKE

Alamat Surat Menyurat (Corresponding Address) :

NO. 85 PERSIARAN RISHAH 11, TAMAN SILIBIN RIA, 30100, IPOH, PERAK.

MAKLUMAT PENGAJIAN (DETAILS OF PROGRAMME)

Program Pengajian

(Programme of Study)

D. Eng PhD Msc

Bidang Pengkhususan

(Field of Specialization )

Electrical Manufacturing Entrepreneurship

Mechatronics Mechanical Technology

Electronics ICT Management

Jenis Pendaftaran

(Types of Registration)

Semester / Sesi Pendaftaran Pertama (Semester / session of

First Registration)

Jangkaan Tamat Pengajian (Expected Completion of Studies)

Full Time :

Part Time :

Nama Penyelia: 1. ..DR. CHONG SHIN HORNG.................

(Name of Supervisor(s)) 2. ..DR. MARIAM MD GHAZALY...............

3. ...............................................................

UTeM 29/1/14

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B. KEMAJUAN PENGAJIAN (PROGRESS OF STUDIES)

i. Tajuk Tesis/Projek Penyelidikan (Title of Thesis/Research Project)

POSITIONING CONTROL OF 1-DOF PNEUMATIC MUSCLE ACTUATOR SYSTEM

ii. Ringkasan Projek (Project Outline)

(Thesis Abstract; Thesis submitted for faculty level approval)

The pneumatic muscle actuator (PMA) is a novel actuator which carries numerous

advantages such as high strength and power/weight ratio, low cost, compact, clean and easy

to maintain features. However, pneumatic muscle actuator has notable nonlinear

characteristics, which makes it difficult to control. The purpose of this research is focused

on experimental system development and parameter characterization of phenomenological

modelling for commercially available Festo Fluidic Muscle Actuator. The model and

parameters obtained from the characterization are validated in simulation and experimental

platform. The major part of the research is focused on the framework of the feedforward +

nonlinear PID control system, and its effectiveness in a 1 degree-of-freedom PMA system

is experimentally demonstrated in comparison with a classical PID controller. The overall

control system comprises of a feedforward controller and a nonlinear PID controller in the

feedback loop which designed based on the exact PMA system characteristics. The design

procedure of the feedforward + nonlinear PID controller is practical and features easy

design procedures. The usefulness and advantages of the proposed controller are shown via

positioning and tracking motion experimental studies. Besides, this study also highlights

the robustness of the feedforward + nonlinear PID controller by examining its performance

in point-to-point and tracking motions in the presence of extra mass. In the robustness

performance, the feedforward + nonlinear PID controller is compared with a classical PID

control systems. The comparative experiments results illustrate that feedforward +

nonlinear PID controller shows the significant motion performances as compared to the

PID controller. The framework used to develop the proposed controller is generally enough

for further investigation in PMA motion control system, further improvement in terms of

positioning accuracy and tracking motion could extend the usefulness of the controller into

other type of rehabilitation applications.

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iii. Pengumpulan Data Data Collection (Tick where appropriate) Completion of Data Collection

1 2 3 4 5 6 7 8 9 10

Start Complete

Remarks : Thesis has been submitted for faculty level approval. Expecting for VIVA in the month of

March 2016.

(Thesis Chapter 4: Perfoamnce Evaluation and Resul Analysis)

Introduction

This chapter begins with the open loop performance validation of the phenomenological

model in simulation and experimental environment. Then, this chapter focuses on validating the

usefulness and adaptability of the proposed controller on the 1-DOF pneumatic muscle actuator

system experimentally. The performance validation of the feedforward + nonlinear PID

controller has been focused on point-to-point positioning and tracking performance in

comparison with the classical PID controller. The positioning and tracking performance of the

proposed controller is examined in several step heights. Final part of this chapter covers the

repeatability, robustness evaluation and analysis in comparison with the classical PID controller.

The chapter is ended with a brief summary on chapter 4.

Phenomenological Model Validation

In order to prove the adaptability and usefulness of the phenomenological model,

simulated open-loop responses using the phenomenological model and experimental open-loop

responses using the actual PMA system are compared. The experimentally determined spring

coefficient Km, damping coefficient Bm and the contractile force coefficient Fce are used in

simulation environment. The simulation block diagram is designed based on the

phenomenological model equation of motion. In order to minimize the model linearization

influence, the experimentally determined coefficient values were fed-in the form of nonlinear

curve fit to predict the PMA contraction in the simulation environment. Accordingly, the validity

of the phenomenological model is confirmed. The step input with amplitude: 150-500kPa

(increment of 50kPa under 0N loading condition) are used to command the PMA system in

open-loop.

Figure 4.1(a) and Figure 4.1(b) illustrate the experimental and simulation responses of

the system under different pressures. The model was tested with the comparison of pressure of

pressure at 150kPa, 250kPa, 300kPa, 350kPa, 400kPa, 450kPa and 500kPa under 0N external

loads correspondingly. The comparative results show identical open loop contraction

performance with a small steady state error. It can be observed that the simulated results agree

with the experimental ones. Besides that, there is no vibration encountered in the transient and

steady-state phase of the simulation and experimental results. In the first simulation results

presented in Figure 4.1 (a) and Figure 4.1 (b), the PMA is inflated by a constant input pressure

P=150kPa and the response of the phenomenological model and the experimental response are

depicted in Figure 4.1(a). Under this applied pressure, the PMA able to reach a maximum

contraction at x=22.93mm in the simulation environment, and x=22.91mm in the experimental

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PMA response, which gives a total steady state error of 0.09%. However, the simulation result

performs faster in term of rise time during the transient response based on the macroscopic

observation. This is caused by the friction acting on the PMA system which slows down the

PMA motion compared to the simulation environment. The open loop result for the higher

contraction which is above 250kPa tally with simulation result. This result is significant to prove

the robustness of the phenomenological model, because the high velocity of contraction during

the higher contraction can cause huge steady-state error. This situation is not obvious in the

presented graphs. The results clearly demonstrate that the phenomenological model is able to

predict the PMA contraction effectively.

0

10

20

30

40

(a)

Experimental Simulation

PM

A C

ontr

action(m

m)

Pre

ssure

(kP

ax0.1

)

Input Pressure:150kPa



0 2 4 6 8 100

10

20

30

40

50


PM

A C

ontr

action(m

m)

Pre

ssure

(kP

ax0.1

)

Time(s)0 2 4 6 8 10


Time(s)

0

10

20

30

40

50

60


PM

A C

ontr

action(m

m)

Pre

ssure

(kP

ax0.1

)




0 2 4 6 8 100

10

20

30

40

50

60


PM

A C

ontr

action(m

m)

Pre

ssure

(kP

ax0.1

)

Time(s) (b)0 2 4 6 8 10


Time(s)

Figure 4.1 : PMA contraction result for a step input in pressure for (a) 150kPa, 200kPa, 250kPa

and 300kPa (b) 350kPa, 400kPa, 450kPa and 500kPa under 0N constant load.

- 5 -

Figure 4.2 demonstrates the steady-state error for different pressures; the figure

summarizes the difference of maximum steady-state error for the simulation and experimental

performance. The comparative open open-loop performance shows some identical performance

at the steady-state for different pressures tested. The steady-state error decrease as the input

pressure increased. The max %100

e

se

x

xx is defines as maximum steady-state error, where

ex is the experimental PMA contraction and sx is the simulated PMA contraction. The results

clearly prove that the phenomenological model is able to perform effectively with the

characterized parameters, by maintaining the maximum open loop steady state error below

0.10%. The result demonstrates that the steady state error for lower input pressure is larger as

compared to the higher input pressure. This situation existed due to highly nonlinear

characteristic of the PMA system. The unexpected static and coulomb friction forces of the

system often give an unexpected force to the table (experimental result). The nonlinear

characteristics also caused by the high static friction (“stiction”) between the sheath and the

bladder of the PMA.

The comparative study has been further validated by plotting the input pressure versus

PMA contraction to study the system motion characteristics. Figure 4.4 shows the experimental

and simulation performance of PMA system. Accordingly, only a small tracking error has been

noticed from the characterized phenomenological model. The overall comparative error of the

simulations and experimental result is below 0.10%. The validation results show almost similar

response is achieved compared to the exact PMA motion. Overall, the characterized

phenomenological model is effective and useful in simulating the PMA contraction.

0 50 100 150 200 250 300 350 400 450 500 5500.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

err

or(

%)

Pressure(kPa)

error data

Figure 4.2 : Steady state error result under different pressure tested with the interval of 50kPa

- 6 -

100 150 200 250 300 350 400 450 500 550

20

25

30

35

40

45

50

55

60

65

PM

A C

ontr

actio

n(m

m)

Pressure(kPa)


Figure 4.3 : PMA system experimental and simulation response

Positioning Performance

The usefulness of the proposed feedforward + nonlinear PID controller is experimentally

evaluated on the 1-DOF pneumatic muscle actuator system. The system is validated in point-to-

point positioning and tracking motion. As above mentioned, the feedforward + nonlinear PID

controller is proposed to improve the residual vibration problem of the PMA system (stick-slip

effect) and to maintain the steady-state error <50µm.

Hence, comparative study between the feedforward + nonlinear PID controller and the

PID controller has been experimentally validated with the positioning and tracking performance

results. The PID controller is designed in order to compare with the proposed controller due to

its simplicity design procedure and control structure. The PID controller is designed using

Ziegler Nicholas tuning method 2. The controller parameter for the proposed controller and the

PID controller are shown in Table 4.1.

Table 4.1 : Controller parameters

Controller Kp Ki Kd

Feedforward +

Nonlinear PID

3.07 x 10-1

11.539 1.00 x10-4

PID 9.21 x 10-1

11.232 1.90 x10-2

Figure 4.4 to 4.7 show the comparative experimental positioning responses of

feedforward + nonlinear PID and the PID controller to step inputs of 5mm, 10mm, 20mm, and

30mm with default mass. The step response, positioning error and the pressure characteristics

are illustrated in the figures. As observed, the PID controller shows poor positioning

performance, with large overshoot and produce oscillatory motion during steady state for the

displacement above 10mm. However, the PID controller produces shorter rise time compared to

the feedforward + nonlinear PID controller for the lower contraction step height as shown in

Figure 4.4 and Figure 4.5. When the step height is increased, it can be seen clearly that the

feedforward + nonlinear PID controller performs better in term of the rise time. Besides that, the

results presented shows that the feedforward + nonlinear PID controller performance is

- 7 -

suppressing the residual vibration (oscillatory motion) as compared to the PID controller.

Moreover, the proposed controller also records shorter settling time to reduce the positioning

error <50µm. The feedforward + nonlinear PID controller could suppress the residual vibration

of the PMA system due to the nonlinear “Compensator B” in the controller block diagram. The

compensator which holds the pressure and displacement characteristics of the PMA system

could make the PMA motion steadier and at the same time reduce the stick-slip effect. The

positioning error graph in Figure 4.5 (b) gives a better view and explains the effectiveness of the

“Compensator D” of the proposed controller to reduce the residual vibration with the recorded

settling time of 6.6871s in comparison to the PID controller which takes 8.1864s to maintain the

steady state error. Figure 4.5 (c) clearly explains the nonlinear effect in the PID controller as

compared to the proposed controller which able to suppress the residual vibration effect. This

positioning result indicates the contribution of the controller to totally eliminate the nonlinear

effect of the system and at the same time produce significant positioning performance in term of

steady state error <50µm.

The PMA system has been examined under different step heights to examine the

influence of the nonlinearity effect. The positioning experiment of 5mm shown in Figure 4.4 is

very significant in this study due to the PMA characteristics. As explained in the literature

review part of this thesis, the PMA used in this research is a high force type. It is important to

note that a significant positioning response could be achieved for small displacement with the

proposed controller. The positioning performance of the two control system has been validated

with 10 times repeatability and the average result is presented in Table 4.2. The quantitative

results in Table 4.2 present the rise time, overshoot and settling time of the two different control

systems.

0 2 4 6 8 10

0

20

40

60

80

100-100

-50

0

50

100

150-100

-50

0

50

1000

5

Co

ntr

ol

Sig

na

l (k

Pa

)

Time (s)

(d)

Ve

locity

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

ce

me

nt

(mm

)

Reference PID FF+Nonlinear PID

(a)

Step Height: 5mm

Figure 4.4 : Experimental step response of the two control system for the step height of 5mm

(default mass)

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0 2 4 6 8 10

0

50

100

150-100

0

100

200

-100

-50

0

50

1000

5

10

15

Con

trol

Sig

nal (k

Pa)

Time (s)

(d)

Velo

city

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

cem

ent

(mm

)


(a)

Step Height: 10mm


(default mass)

Figure 4.6 and Figure 4.7 shows the experimental responses of the two control systems

for the step height of 20 mm and 30mm with default mass. The step responses, error graph,

velocity characteristics and input pressure are illustrated. As observed obviously, the proposed

feedforward + nonlinear ID controller show significant response with smaller overshoot and

faster settling time as compare d to the PID controller. However, the PID controller produces

extremely high overshoot at the both step heights. When te step height is increased, it can be

seen clearly that the feedforward + nonlinear PID controller performs better in suppressing the

residual vibrations as compared with PID controller. The above mentioned response is clearly

shown in Figure 4.6 (c) and Figure 4.7 (c). The input pressure result demonstrated in Figure 4.6

(d) and Figure 4.7 (d) explains the effect of linearizer in the controller block to maintain the

input pressure to the system to by linearizing the coulomb friction effect during transient

response. Moreover, the feedforward + nonlinear PID controller also takes shorter positioning

time to reduce the error <50µm.

- 9 -

0 2 4 6 8 10

0

50

100

150

200

250-200

-100

0

100

200

300-100

-50

0

50

1000

10

20

30

Co

ntr

ol

Sig

na

l (k

Pa

)

Time (s)

(d)

Ve

locity

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

ce

me

nt

(mm

)


(a)

Step Height: 20mm

Figure 4.6 : Experimental step response of the two control system to step height of 20mm

(default mass)

- 10 -

0 2 4 6 8 100

100

200

300

400

-50

0

50

100

150

200

-100

-50

0

50

1000

10

20

30

40

Con

trol

Sig

nal (k

Pa)

Time (s)

(d)

Velo

city

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

cem

ent

(mm

)


(a)

Step Height: 30mm


(default mass)

The quantitative results in Table 4.2 summarize the rise time, overshoot and the settling

time of both the controllers in point-to-point positioning performance. Although the analysis

results show that the PID controller produce shorter rise time and smaller overshoot for 5mm

step height compared to the proposes controller, but the proposed controller has showed faster

settling time which is very significant and important in positioning control system. The proposed

controller recorded faster settling time and smaller overshot as compared to the PID controller.

At the step height of 30mm, the proposed controller recoded smaller overshoot compared to the

PID controller which is 7.8464% and 23%. This situation explains the effectiveness of the

proposed controller to suppress the nonlinear effect of the system and to maintain a fast response

and smaller steady-state error. Besides that, the small standard deviation value recoded in Table

4.2 for the rise time, overshoot and settling time proves the consistency of the proposed

feedforward + nonlinear PID controller in point-to-point positioning performance for 10 times

repeatability experiment.

Overall summary shows that the proposed controller presents better rise time, overshoot

and settling time as compared to the PID controller. On the other hand, the feedforward +

nonlinear PID controller is able to show its robust characteristics by maintaining the overshoot

response less than 9% for the range of step height tested. Besides that, the feedforward +

nonlinear PID controller also performed better in term of positioning accuracy by maintaining

the steady state error between ±50µm and at the same time shorter settling time to reach the

steady state. This results proves that the adaptability and functionality of the proposed controller

in point-to-point positioning performance.

To further validate the effectiveness of the proposed controller, steady-state error

analysis was conducted based on the experimental data. Table 4.3 presents summarized the

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average and standard deviation of maximum steady-state errors in 10 positioning experiments.

As observed obviously, the result presented in Table 4.3 shows that the positioning accuracy of

the proposed controller is maintained between ±50µm although the step height has been

increased. This result proves the adaptability of the controller towards the height changes and the

working range.

iv. Analisis Data

Data Analisis (Tick where appropriate) Completion of Data Analysis

1 2 3 4 5 6 7 8 9 10

Start Complete

Remarks :

(Analysis of Chapter 4)

Robustness Performance Evaluation

In practical applications, the loading weight will be changed. In order to validate the robustness

of the proposed feedforward + nonlinear PID controller, it is further validated with an increased mass

experimentally which is extra of 3.115kg (30.558N) from the default of 4.710kg (46.205N). The

positioning responses with the increased mass are shown in Figure 4.12 to Figure 4.15. The control

parameters and the system setting are as per the previous experiment and no modification has been

done. The feedforward + nonlinear PID controller successfully demonstrates satisfactory robust

performance in response to the increase of mass, by producing smaller overshoot as compared to the

default mass tested. This response is obviously seen in Figure 4.12(a) whereby the recorded overshoot

for the proposed controller is about 4.820% as compared to the PID controller which records 9.527%.

The recoded value is smaller if compared to the positioning performance of the proposed controller for

default mass which is about 8.4502%. Besides that, the proposed controller also demonstrated faster rise

time and settling time as compared to the PID controller for the step height below 30mm. This is

obviously seen from the Table 4.5, whereby the proposed controller recorded smallest standard

deviation for the recoded rise time, settling time and overshoot for the step height below 30mm. The

proposed feedforward + nonlinear PID controller able to suppress the nonlinear effect and overshoot

effect to maintain the steady state error between ±50µm at average of 6s for all the step height.

Although the PID controller recoded better performance in term of rise time, overshoot and settling time

but the calculated standard deviation subsets the situation by smaller value for the proposed controller.

The standard deviation value proves the accuracy and consistency of the proposed controller in

repeatability result. The experimental results indicate the strong robust performance of the feedforward

+ nonlinear PID controller. Even though the PID controller demonstrates faster rise time in comparison

- 12 -

to the proposed controller for positioning result of 10mm, but it takes longer positioning time to

eliminate the steady state error which is 50% faster. The robust positioning performance of the two

control system has been validated with repeatability performance analysis. Table 4.6 presents the

positioning performance of five (5) experiments for 2 controllers with increased mass. Overall, the

feedforward + nonlinear PID controller demonstrates better positioning performance when the mass is

increased on the PMA system.

The proposed controller performs decent for lower displacement of 10mm and 20mm in terms of

steady state error, while the PID controller demonstrated longer settling time due to the residual

vibration appears during steady state. This response can be seen clearly from the Figure 4.13 and Figure

4.14 (c) and (d). The velocity graph shown is the Figure 4.12 to Figure 4.15 gives a clearer view of the

positioning performance of the propose controller. The Figure clearly shows the ability if the proposed

controller to suppress the residual vibration effect of the PMA system. The pressure graph demonstrated

in the Figures is to prove the ability of the proposed controller in suppressing the highly nonlinear effect

of the PMA system. The linearizer in the proposed controller block helps to suppress the residual

vibration of the system by linearizing the pressure to the system. This is an important point to support

the proposed controller since the PMA system is driven by pressure. Besides that, the pressure in PMA

also contributed towards the nonlinear effect of the system.

The response of the feedforward + nonlinear PID controller is robust to adapt towards the load

changes in the PMA system. This proves that the proposed controller is less sensitive to disturbance

than the PID controller. The robustness characteristic of the controller is partially contributed by the

feedforward element in the controller, whereby the feedforward element supplies the enough voltage to

drive the system to a desired position in transient phase before disturbance occurs. The feedforward

element which supported by the “Compensator B” in feedback loop, further enhance the robust

performance of the system by maintaining the steady state error below <100µm. It can be concluded that

the response of the proposed controller with the pressure linearizer in the control block, helps to

suppress the overshoot, faster rise time and the most significant is the faster settling time to reach steady

state. As a conclusion, it can be seen that the proposed controller has better robust performance for the

PMA system with loading uncertainties.

- 13 -

0 2 4 6 8 10

0

20

40

60

80

100-50

0

50

100

-100

-50

0

50

1000

5

Co

ntr

ol

Sig

na

l (k

Pa

)

Time (s)

(d)

Ve

locity

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

ce

me

nt

(mm

)


(a)

Step Height: 5mm

Figure 4.8 : Experimental step response of the two control system for the step height of 5mm (increased

mass)

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0 2 4 6 8 10

0

50

100

150-50

0

50

100

150

-100

-50

0

50

1000

5

10

Co

ntr

ol

Sig

na

l (k

Pa

)

Time (s)

(d)

Ve

locity

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

ce

me

nt

(mm

)


(a)

Step Height: 10mm


(increased mass)

- 15 -

0 2 4 6 8 10

0

50

100

150

200

250-100

0

100

200

-100

0

100

0

5

10

15

20

25

Co

ntr

ol

Sig

na

l (k

Pa

)

Time (s)

(d)

Ve

locity

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

ce

me

nt

(mm

)


(a)

Step Height: 20mm


(increased mass)

- 16 -

0 2 4 6 8 10

0

100

200

300-100

0

100

200

300

-100

-50

0

50

1000

10

20

30

40

Con

trol

Sig

nal (k

Pa)

Time (s)

(d)

Velo

city

(mm

/s)

(c)

Err

or

(m

)

(b)

Dis

pla

cem

ent

(mm

)


(a)

Step Height: 30mm


(increased mass)

Figure 4.16 illustrates the experimental tracking response of two types of controllers under

triangular reference input with increased mass. The remaining spectral analysis of tracking error for

triangular input at control time of 15s input is attached in Appendix C. The proposed controller has been

tested at the same displacement of 5mm, 10mm, 20m and 30mm. From the macroscopic view, the

proposed controller demonstrates better maximum tracking error result as compared to the PID

controller. Besides that, PID controller performed poor in suppressing the residual vibration during the

contraction and relaxation phase of the in the tracking response. The feedforward + nonlinear PID

controller is able to perform well in the robustness tracking performance experiment by maintaining

better motion accuracy (no stick- slip effect) compared to the PID controller. The significant positioning

performance of the feedforward + nonlinear PID controller with the increased mass proves the

robustness and adaptability of the controller. The above mentioned statement is supported by the

tracking analysis result presented in Table 4.7. Although the proposed controller performed poor in

terms of error root mean square, the ability of the proposed controller to suppress the residual vibration

effect (stick-slip effect) during the contraction and relaxation phase and at the same time smaller

maximum tracking error is the evident of the robust performance. Overall, the feedforward + nonlinear

PID controller is able to perform consistent in positioning and tracking performance under the default

mass and increase mass by compensating the nonlinearity of the PMA system. The positioning and

tracking performance result and analysis for the proposed controller presented in this thesis is a solid

evident of the applicability and adaptability of the proposed feedforward + nonlinear PID controller into

nonlinear PMAS system. Future works will be focused more on accuracy and precision, improvement in

term of accuracy and precision is focused in order to develop a more robust and precise controller for 1-

DOF pneumatic muscle actuator system. The research and development for the PMA system is still in

ongoing process in order to contribute to the field of pneumatic muscle actuator system.

- 17 -

In order to verify the usefulness of the proposed controller in the tracking motion (increased

mass), spectral analysis has been done. As illustrated in Figure 4.17, the PID controller has shown

higher magnitude as compared to the feedforward + nonlinear PID controller in the low frequencies.

This characteristic is obviously seen from the range of 0 to 50Hz frequency. The spectral analysis

verifies that the feedforward + nonlinear PID controller has the ability to compensate the nonlinear

effect of the PMA system. The magnitude of the feedforward + nonlinear PID controller is lower as

compared to the PID controller and proves that the proposed controller is better as compared to the PID

controller. Although the PID controller performed well in terms of root mean square error, the spectral

analysis proved the feedforward + nonlinear PID controller performed better in term of compensating

the nonlinearities. Overall, the feedforward + nonlinear PID controller show performed well in tracking

motion as compared to the PID controller.

Table 4.2 : Positioning performance of five (5) experiments for 2 controllers (increased mass)

Step height Performance index Feedforward + Nonlinear

PID

PID

5mm tr (s) average 4.780 x 10-2

3.831 x 10-1

standard deviation 2.900 x 10-3

2.069 x 10-1

OS (%) average 4.820 9.257

standard deviation 1.944 4.131

ts (s) average 6.508 7.242


2.730


1.630 x 10-1


4.500 x 10-2

OS (%) average 6.688 6.096


1.057

ts (s) average 4.518 9.672


3.185 x 10-1


1.359 x 10-1


2.900 x 10-2

OS (%) average 6.110 8.290


ts (s) average 6.182 9.912

standard deviation 3.019 7.7 x 10-2


1.130 x 10-1


1.030 x 10-2

OS (%) average 6.679 5.499


ts (s) average 4.041 3.672


3.240

- 18 -

0 5 10 15 20 25 30

-1

0

1

0

1

2

3

4

5

6

Err

or(

mm

)

Time(s)

Dis

pla

ce

me

nt(

mm

) Reference FF+Nonlinear PID PID

(a)

0 5 10 15 20 25 30

-1

0

1

0

2

4

6

8

10

12

Err

or(

mm

)

Time(s)(b)

Reference FF+Nonlinear PID PID

Dis

pla

ce

me

nt(

mm

)

0 5 10 15 20 25 30-2

-1

0

1

20

5

10

15

20

Err

or(

mm

)

Time(s)

Dis

pla

cem

ent(

mm

) Reference FF+Nonlinear PID PID

0 5 10 15 20 25 30

-2

0

2

05

101520253035

Err

or(

mm

)

Time(s)

Reference FF+Nonlinear PID PID

Dis

pla

ce

me

nt(

mm

)

Figure 4.12 : Experimental tracking response of two types of controllers under triangular reference input

of (a) 5mm, (b) 10mm, (c) 20mm and (d) 30mm for the control time of 30s (increased mass)

0 50 100 150 200 2500

200

400

600

800

1000

0 10 20 30 40 500

20

40

60

80

100

Magnitude

Frequency (Hz)

FF+Nonlinear PID

PID

Spectrum Analysis of the Error

Amplitude: 5mm, Frequency: 0.1Hz

0 50 100 150 200 2500

200

400

600

800

1000

0 10 20 30 40 500

20

40

60

80

100

Magnitude

Frequency (Hz)

FF+Nonlinear PID

PID



(c) (d)

- 19 -

0 50 100 150 200 2500

200

400

600

800

1000

0 10 20 30 40 500

20

40

60

80

100

Magnitude

Frequency (Hz)

FF+Nonlinear PID

PID



0 50 100 150 200 2500

200

400

600

800

1000

0 10 20 30 40 500

20

40

60

80

100

Magnitude

Frequency (Hz)

FF+Nonlinear PID

PID



Figure 4.13 : Spectral analysis on triangular input tracking error (increased mass)

Table 4.3 : Tracking results of one (1) experiment for 2 controllers (increased mass)

Reference Input Controller

FF + Nonlinear PID PID

xxr max

(mm)

RMSe

(mm)

xxr max

(mm)

RMSe

(mm)

Triangular 5mm, CT=15s 5.05 x 10-2

5.521 x 10-1

3.368 x 10-1

3.269 x 10-1

CT=30s 1.388 x 10-1

4.164 x 10-1

1.778 x 10-1

2.044 x 10-1


9.930 x 10-1

6.890 x 10-1

5.062 x 10-1

CT=30s 7.100 x 10-1

6.652 x 10-1

4.530 x 10-1

3.069 x 10-1


1.3748 6.840 x 10-1

9.605 x 10-1

CT=30s 4.770 x 10-1

8.754 x 10-1

9.890 x 10-1

5.560 x 10-1

Triangular 30mm, CT=15s 1.0060 1.5962 4.480 x 10-1

1.3780

CT=30s 3.140 x 10-1

1.0341 2.900 x 10-1

7.795 x 10-1

v. Bab yang telah diselesaikan dan kemajuannya (Chapter completed and progress to date)

Number of Planned Chapters : ___5___________ Number of Completed Chapters : ___-____________ Percentage of Progress : ___96___________%

vi. Tarikh jangkaan penyerahan draf tesis (Expected date of Thesis draft submission)

Original Submission Date : ___1/7/2015____ New Expected Submission Date : ___9/1/2016____(Thesis to reach PPS)

- 20 -

vii. Kekerapan berjumpa Penyelia (Frequency of meeting Supervisor(s))

viii. Faktor yang dikenalpasti mengganggu penyelidikan (jika ada) (Factors affect the progress of research (if any))

-

1) Average meeting: 3 times a week. 2) Progress Presentation to supervisor 2 times a month (presentation style). To summarize the

overall findings for the month, data analysis and discussion. Besides that, session for next step and research plannings.

- 21 -

C. AKTIVITI PELAJAR SEPANJANG PENGAJIAN (STUDENT’S ACTIVITIES THROUGHOUT STUDIES)

i. Senaraikan Pembentangan / Penerbitan Kertas Kerja, menghadiri seminar dll.

(List all Paper published / presented, seminar attended, etc)

(Publications: 1 Journal and 3 conference paper) 1. Vasanthan Sakthivelu, Chong Shin Horng, Mariam Md Ghazaly., 2016.

Phenomenological Modeling and Classical Control of Pneumatic Muscle Actuator

System. Journal of Control, Automation and electrical Systems (IJCA),Vol. 9(1).

[Accepted] (SCOPUS INDEX Q2)

2. S.Vasanthan, and Shin-Horng Chong, 2013. Motion Control of Pneumatic Muscle

Actuator: Experimental Setup and Modeling. Proceedings of the IEEE student

Conference on Research and Development (SCOReD), pp. 60-64.

3. S.Vasanthan, Shin-Horng Chong and Mariam Md Ghazaly, 2014. Modeling the

Pneumatic Muscle Actuator using Phenomenological model. Proceedings of the 2nd

Power and Energy Conversion Symposium (PECS), pp. 339-344.

4. S.Vasanthan, and Shin-Horng Chong, 2015. Motion Control of a 1-DOF Pneumatic

Muscle Actuator Positioning System. 10th

Asian Control Conference (ASCC). [Accepted]

ii. Kegiatan Bukan Akademik

(Non-academic activities)

iii. Penganugerahan/Penghargaan

(Awards/ Recognitions)

1. Certificate of Appreciation for the poster presentation at The 10th Asian Control Conference 2015 (ASCC 2015)

Saya mengaku segala keterangan yang diberi di atas adalah benar. (I declare all the statements above are true)

.........28 December 2015............................ ...............S.Vasanthan................... Tarikh Tandatangan Pelajar (Date) (Signature of Student)

Documents

UTeM 29/1/14 UNIVERSITI TEKNIKAL MALAYSIA MELAKAportal.utem.edu.my/iSMPS/ProgRpt/M011310008_1-20152016.pdf · positioning and tracking motion experimental studies. Besides, this study