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App. B—Commissioned Background Papers . 63

uncertainties,

and

adapt

to

or require too much ability to see

changing

circumstances.

Before

robots

and

can

feel sig–

nificantly

impact

productivity

of

the

economy

as

a

whole,

they must be used in hundreds of thousands

of

applications.

This

will

not

be

possible

and even before

millions a large

number of technical problems are solved. TECHNICAL PROBLEM AREAS One of the first problems is accuracy.

Robot

positioning

accuracy

needs

of

most

robots

is

to be improved.

on

the

order

of

Although the repeatability

0.050

inch

over

its

work-

ing

volume

(and

in

some

cases

as

good

as

.005

inch),

the

ab-

solute inch,

positioning accuracy may

or

even

O.

500

inch

in

be off as some regions

much of the

as

O. 250

reach

en-

velope.

to

an

Thus,

arbitrary

it is not possible to program a

mathematically

defined

point

in

robot to go a coordinate

space and have any assurance that the robot

than a half of an gramming a robot

inch. from a

This creates major computer terminal,

will come closer problems in pro-

or

in

transfer-

ring programs from one robot to another. taught its program separately by leading

Each robot must be

it

point

by

point

through its Presumable/

job, this

a tedious accuracy

and costly task. problem could be

solved

through

closer cost. trated

robot manufacturing tolerances)

although not without

alternatively,

in

Figure

1,

calibration procedures such might allow each robot to

as illus– offset its

off-line program points to

inaccuracies.

However, no

compensate for its efficient methods of

mechanical robot cali-

bration is not

have yet been developed> and robot control

presently

designed

to

use

calibration

tables

software

for

im-

proving absolute positioning accuracy.

Until this

absolute

position

accuracy

problem

is

solved)

robot

assembly

in

the

small batch environment will be

uneconomical.

Teaching

a

robot

every

point

in the trajectory of

a complex assembly

task

is

a

time

consuming

job

which

may

take

many

times

longer hand.

than Thus,

would using a

be required to perform the same task by robot for small lot batch assembly can-

not be economical until by off-line programming

software can be efficiently (i.e., programming from a

produced computer

terminal}. Second, dynamic performance must be improved.

Present

day

robots are human labor

too slow and in assembly.

clumsy to effectively compete

Two

possible

exceptions

to

with this

are in process

arc itself,

welding where speed is governed by and spot welding where the task

the welding corresponds

to moving a heavy points in space -- a

welding gun through procedure which the

a simple robot is

string of particu-

larly other

adept types

at of

executing.

assembly

and

However,

if robots are to

construction

tasks,

they

perform must be

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