introduction demonstration dp

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Introduction demonstration DP. Using models for MT218 Mechatronics in MT. H.T. Grimmelius Assistant professor (lecturer) Marine Engineering Delft University of Technology. Lecture content. A little background Description of hard- and software Some theory Goal this afternoon. - PowerPoint PPT Presentation

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1

Introduction demonstration DPUsing models for MT218 Mechatronics in MT

H.T. GrimmeliusAssistant professor (lecturer) Marine EngineeringDelft University of Technology

2

Lecture content

• A little background• Description of hard- and software• Some theory• Goal this afternoon

3

Mechatronics

• Mechatronica is de naadloze combinatie van verschillende complementaire technologieën, die op een integrale wijze met elkaar samenwerken

(Federatie Hydrauliek en Pneumatiek)

• Mechatronics is the combination of MECHAnical systems with elecTRONics and informatICS

5

Mechatronics

• Main components:• The actual system or process• Actuators to move or exert a force• Sensors to measure actual state• Controls to maintain required state or change

state

• Additionally required: data acquisition system

Mechatronics

•Measurements•Network theory•Digital signal-processing

•Filtering

•Digital real-time control

•Mechanics•Dynamics•Hydro

•Sensors•Actuators

project

7

Available hard- & software

• System: model ship• Actuators: propulsors and servo’s• Sensors: position (x-y), heading and shaft

speeds• Controls: Simulink based system for “weather

vaning”• Data acquisition through PC

8

Available hard- & software

• “COTS” equipment:• Model: standard kit• Actuators: all motors, speed controls and

servo’s• Communication: PC with standard I/O board

• Not “COTS”:• Sensors: developed for this application• Controls: Simulink based programme with

GUI

Commercial Of The Shelf

9

• Wished:• Several possibilities for Weather vaning DP• Affordable and maintainable

• Implementation:• Two azimuthing thrusters (4 degrees of freedom)• Bow thruster (1 degree of freedom)• COTS• Controlled with PW signal

Actuators

t [ms]

U [V

]

10 2012

max min

~0

~5

t [ms]

U [V

]

10 2012

max min

~0

~5

10

Location sensor

• Wished:• Affordable location sensor• Clear & simple working principle• Suitable to be used in towing tank

• Implementation:• Telescopic rod with angular (SITW: Stiff Inverted Taut Wire)

11

Speed sensor

• Wished:• Shaft speed feedback of both thrusters• Clear & simple working principle• Accurate also at low rpm

• Implementation• Optical pick-up• Disc with 15 holes• Signal conversion (pulse DC)

12

Communications

• Wished:• Continuous• Possibility for high resolution• Everything from within Matlab/Simulink• Good support

• Implementation:• Real time I/O card MF614 by HumoSoft• Digital: 8 in/8 out; analogue 8 in/4 out + 4 PWM

13

Control system

• DP control• Only X-Y position controlled, heading is free• Two decoupled PID controllers with anti-wind

up

• Other controllers• Shaft speed controllers• Very suitable for application of Ziegler &

Nichols

14

• Simulink models generated automatically• Three working environments

• On-line for actual sailing (closed loop)• On-line for testing harware (open loop)• Off-line simulation environment

Control system

• Graphical user interface within Matlab

15

Control system: on-line

Controller Power configuration

Positiontransformation

Position error

Required

forced

Actuator

settings

Position data

Real-timeoutput

PWMsignals

Real-timeinput

Measured

voltages

16

Control system: on-line testing

• On-line testing gives the possibility to directly control the actuators and read the sensor signals

Actuator

settings

Position data

Real-timeoutput

PWMsignals

Real-timeinput

Measured

voltages

17

Control system: off-line

• For off-line simulation all hardware should be available in software modulesController Power

configurationPosition

transformation

Position error

Required

forced

Actuator

settings

Position data

Simulatedactuators

Simulatedship

Simulatedsensors

ForcesPosition

18

Possible configurations

One thruster, full control Combined

Two thrusters, fixed relative angle

Combined

First thruster forward, second thruster lateral

First Second

One thruster forward, bow thruster

thruster

Bow thruste

r

19

Education

• Two deliverables• Test: does it work• Report: why did it work

• Student reaction‘Thought we could do full DP, but problems

were already big enough now ...’

20

Research projects

• thruster interaction: angles• thruster interaction: rpm• thruster – hull interaction

21

Demonstration & publicity

22

Manoeuvring & wind modelling

• Manoeuvring modelling• Wind modelling

23

Equations of motion

pqIIrINrpIIqIMqrIIpIK

qupwwmZpwruvmY

rvqwumX

yyxxzz

xxzzyy

zzyyxx

)()()(

)()()(

Body with 6 degrees of freedom

24

Reducing degrees of freedomAssumptions• no waves• no change in total mass during manoeuvre• no change in distribution of mass during manoeuvre• rotation around y-axis does not influence motion in

x-y plane

rIMruvmYrvumX

zz

)()( only forces and moments

in the x-y plane influence manoeuvring behaviour

25

Hull forces

• Forces depend on:• Speed of the ship through the water• Rate at which this velocity changes• Shape of the hull• Characteristic of the water

• No confinements present (deep water, open sea)

• No waves( , , , , , )HULLF f u v r u v r

26

Hull forces

• From Taylor expansion to the third power:

• Which leads for X to:

2 212!

3 2 2 313!

( , ) ( , ) [ ( , ) ( , )][( ) ( , ) 2 ( , ) ( ) ( , )][( ) ( , ) 3( ) ( , ) 3( ) ( , ) ( ) ( , )] ...

x y

xx xy yy

xxx xxy yyx yyy

f x x y y f x y x f x y y f x y

x f x y x y f x y y f x y

x f x y x y f x y y x f x y y f x y

02 2 21

2!3 3 3 2 21

3!2

[ ][ ... 2 2 ... 2 ][ ... 3 3 ..3 6 6 ... 6

hull u v r u v r

uu vv rr uv ur vr

uuu vvv rrr uuv uur

rrv uvr uvu uvr

X X X u X v X r X u X v X rX u X v X r X uv X ur X vrX u X v X r X u v X u rX r v X uvr X uvu X

]uvr

27

Hull forces

• Simplification by Inoue( ) ( )hull x y vrX m u m X vr X u

22 ( ' ' ' ' ' ' ' ' ' ' ' ' ')hull y x v r v v v r r rY m v m ur LTU Y v Y r Y v v Y v r Y r r

2 22 ( ' ' ' ' ' ' ' ' ' ' ' ' ' ' ')hull zz v r vvr vrr r rN J r LTU N v N r N v v r N v r r N r r

212

212

2 212

2 2

'

'

'

XXLTUYYLTUNNLTU

U u v

28

Hull forces

• Coefficients estimated based on L, B, T and cB

2

3 2

' 4' 1.42' 0.435 1.7 (1 )

' 0.472 (1 )'' 0.54

' 25.34 4.66 0.44 0.098

' 0.44 0.065

' 34197

r

bb

br b

rr b

r

b b brr

brr

br

Y k

C BY kL

TY CB

TY CB

N kN k k

B C B C B CNL L L

C TNBB CN

L

4 3 2

18941 3909 353.8 11.9b b bB C B C B CL L L

gyrrk

L

29

Hull forces

• Other parameters to be estimated• Hydrodynamic mass in x and y direction• Hydrodynamic mass moment of inertia I• Straight line resistance

30

Hull forces

• For low Fr and large β:• No longer valid

because of Munk’smoment

31

Wind forces

• Calculated with wind speed only (ship speed very low)

2

2

2

( ) 2( ) 2( ) 2

wind X wind lat wind

wind Y wind front wind

wind N wind lat wind

X C A U

Y C A U

N C A L U

32

Source of constants

• Brix:• Semi emperical

33

AD converter

time

ampl

itude

time

ampl

itude

34

AD converter: resolution

• Number of values = 2bits

• 8 bits: 256 levels• 10 bits: 1024 levels• 12 bits: 4096 levels

• Error1 Full Scale2b

35

Aliasing

time

amplitude

36

Anti-aliasing

• Sample at at least twice the highest frequency• Filter out high frequency components before

sampling

• Highest frequency: closed loop gain > 3 dB• Use bode plot!

• Rule of thumb: 2 to 4 samples during rise time of step response

37

High frequency aliasing

38

DA converter

-

+

U 1

Uo = ?

R2

R1

R1U 2

39

DA converter

01 01 01 01 01 01 01 01

B7 B6 B5 B4 B3 B2 B1 B0

Ub

-+

Rt

Uu1K 2K 4K 8K 16K 32K 64K 128K

40

Goal of today

• Checkout system• Set controller variables• Check results

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