Mec

hani

cal b

ody

Front ball bearing

Housing Tool

Back ball bearing

Ele

ctri

cal c

ompo

nent

s Electrical measuring equipment

Drive Power supply

Cou

plin

g

Equ

ipm

ent

Con

trol

har

dwar

e

Sens

ors

Electronic devices

Coupling

Operating system

Programming tools

Control application software

Data manipulation tools

Methods Dynamic modeling Power flow modeling Thermal effects Diagnostics Control Flexibility Balancing Compensation

In order to improve productivity, high-speed spindle systems (HSSS) are used in the production cells. Especially, they are employed for machining, micromachining,

milling, drilling, data reading and recording applications, aerospace, heavy industry, consumer industry, and in many manufacturing sectors.

Spring Feedback

Amp

Force generator

m1

elspindleF _

mispindleF _epspindleF _ wlspindleF _Ideal case

aospindleF _

cvspindleF _

sfspindleF _

Coloumb friction feedback

Viscous friction feedback

c

d/dt aospindleF _

+/-F *sign( )

+/- d

+

+ -

+ +

+

+

spindle with friction

Friction Compensation

Correction of non-linear process statics

A translational motion model of a high-speed spindle system

lspindleespindlespindleallspindle Tdt

dBTT

dt

dJ __2

2

_

a

b

c

d

e f gh i

j

ml

k

n

o

p

q

r

s

Graphical representation of flow of power within the spindle

EMB

ROTOR

Figure-16.4 shows the schematic diagram of this custom-built spindle system with respect to optimized design specifications (Refer Table-16.4.)

0

5000

10000

15000

20000

25000

30000

35000

1 15 29 43 57 71 85 99 113

127

141

155

169

183

197

211

225

2390 25 50 75 100 125 150 175 200 225 250 275

980 N

1876N1444N

Time in Seconds

Speed in Rev. per minute

Developers have studied the operating points i.e., the Quotient Point (Q-point) of the rotary systems since long. The Q-point curves, which are the graphic representation of the dynamic model equations, help the engineer to view the performance of the system instantly. Theoretically, the Q-points are described using state space method. Experimentally, they are plotted from the I/O data.

Loss due to friction in a typical high speed spindle system.

0

100

200

300

400

500

600

700

800

900

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 310 5 10 15 20 25 30

0

5

10

15

2

0

25

30

35

40

45

In W

att

In RPM

Loss due to viscous shear of the air in between the stator and rotor of the high speed spindle systems.

1 = Heat generation at motor at speed 30000 RPM2 = Heat generation at motor at speed 1500 RPM3 = Heat generation at front bearing at speed 30000 RPM4 = Heat generation at front bearing at speed 15000 RPM5 = Heat generation at real bearing at speed 30000 RPM6 = Heat generation at real bearing at speed 15000 RPM

1

2

3

4

5

60 4 8 12 16 20 24 28 32 36 40 45 50 55 60 65

-50

0

50

1

00

150

2

00

250

3

00

350

4

00

450

5

00

Time

Rel

ativ

e he

at g

ener

atio

n

Heat generation with respect to time

-5

0

15

20

0 30 60 90 120 150 180 210

Temperature in degree C

Time in Second

Front bearing

Rear bearing

Temperature with respect to time

0102030405060708090

100

1 10 19 28 37 46 55 64 73 82 91 100

Axial load in Kgf

Dis

pla

cem

ent

in m

icro

met

er

481953726

Relationship between axial load and displacement because of thermal deformation

 

Curve No. Curve fitting formula Heating/Without heating

1 18.1*L^0.26 No heating

2 8.1*L^0.37 No heating

3 8.1*L^0.36 No heating

4 7.6*L^0.52 Heating

5 6.3*L^0.45 Heating

6 1.3*L^0.68 -

7 10.1*L^0.30 No heating

8 3.5*L^0.67 Heating

9 9.1*L^0.37 No heating

concerned but also of other mechatronic systems. Mass unbalances are the major sources of vibration. A powerful balancing method, called Electro-Magnetic Balancing (EMB) technique has been developed in the micromanufacturing laboratory, K-JIST. The photograph of an EMB for HSSS.

HSSS are vulnerable to vibration. Balancing is an important area as far as design and developme-nt of not only HSSS are

2

1 = Roundness of the Shaft after compensation (EMB)2= Roundness of the Shaft before compensation

Y-a

xis

disp

lace

men

t in

mic

rom

eter

X-axis displacement in micrometer

-5 -4 -3 -2 -1 0 1 2 3 4 5

-5

-4

-

3

-2

-1

0

1

2

3

4

5

Vibration compensation by the use of Electromagnetic Balancer (EMB). A new technique for compensation of induced mass unbalances.

Residual Generator

Fault size, type, location, time, cause

Controller Actuator ProcessDynamics

Sensor

Decision making

UR Y

Model-based DAP, on the other hand rely on quantitative mathematical relation between the I/O (hence model of the plant) and depends only on the availability of a mathematical model of the plant. This involves two tasks, generation of residuals and design of decision rules based on these residuals.

Normal

Faulty

F-1 = Fault due to thermal deformationA measure of radial pressure in exerted

Time

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Preload applied deliberately

0 300 600 900 1200 1500

F-1 = Fault due to thermal deformation ; Change of Coulomb Friction Coefficient

1

0.8

0.6

0.4

0.2

0

-0.2 Time

0 300 600 900

F-1

F-1

F-2 = Bearing jam F-2 = Bearing jam

0 600 1200 1800 2100 2400 2700

Preload applied deliberately

F-2 F-2Time Time

0 600 1200 1800 2100 2400 2700

Insufficient cooling Insufficient cooling

12

10

8

6

4

2

0

0.05

0.04

0.03

0.02

0.01

0.00

-0.01

allspindleJ _ Power; (VI)

Some FDI results based on spectral analysis and stricture estimation using model equations. Figure illustrates how the strictures are changed with respect to additive faults.

(a) Fault due to shaft wear. (b) & (c) Fault due to thermal deformation (d) & (e) Fault due to spindle jam

Formulation Stage

Inventory Stage

Tracking Stage

Validation

1. Scope(i) component classification(ii) characterization

2. Model construction(i) Identification of variables(ii) Determination of Life Span Value

1. Algorithm generation2. Design (Hw & Sw)3. Data acquisition

1. Decision maker ( Watchdog)

Data Acquisition Display

GUI, Seven segment

Disk files

File handling

Miscellaneous

Configuration

1. Components-based2. Distributed Control

Machine control requirements

SEA development knowledge base and workbench

A SEA variable must have a life span value (LSV). Life Span Value (LSV) is defined as a predictable value i.e., LSVs are the measure of active life of the variables defined for a specific component/device.

Central Controller

Interfacing

Sensors Actuators

Valves Switches

Drives Controllers

Etc..

Parallel connection

A schematic diagram of Centralised Control

C

C

C

C

Sensors

Actuators

Drives

Etc.

P L A N T

C O N T R O L L E R S

A schematic diagram of DCS

N E T W O R K E D

Plant

In resent years industrial automation and control systems preferred to implement Distributed Control System (DCS) instead of centralized, because of its advantage of great flexibility over the whole operating range.

Process/System level

Network level

Component level

Management level

Sensors, Actuators, PLCs, PCs (hardware)

Protocol, System image (firmware)

SC to OC, Config., Registration (Compiler, COM, DDE, OLE )

Installation, Binding, Monitor & Control

Distributed control can be leveled into four layers of automation services. Component level is the physical layer that connects devices, PC, industrial PC, PLC, microprocessor, micro-controller etc. Network interface layer is similar to MAC sub-layer of the link layer protocol. Process layer includes application layer features. Application layer defines the variables, which are responsible to transfer data from one place to other when they are connected logically.

Converter

Bearing

Displacement & Vibration sensors

Current sensors

Driver

FIELDBUS (LON)

Balancer

Schematic diagram of the spindle system in the context of control interfacing

N1 N2 N3

Interfacings Interfacings Interfacings

Drive (actuator)

Position sensors(Encoders)Temperature And vibration sensors

DisplayAlarm,Switch,Buttons

TransceiverTransceiverTransceiver

Fieldbus based DCS network

NT, LNS, VB6, OS for DCS, Simulation tool

Graphical User InterfaceClient ServerObject OrientedVirtual design

Code-N2Code-N1 Code-N3

System Image

HIGH SPPED SPINDLE MACHINE(co-ordination, synchronization, acknowledgement, timing )

Sp

ind

le c

ontr

ol r

eali

zati

on u

sin

g D

CS

sch

eme