Reference

AT'L INST. OF STAND & TECH

- - Ill'"" ' "

MBS

Fubli -

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\b, ^^^^ ^ NBS SPECIAL PUBLICATION 602

U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards

ones

Research Workshop
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act ol Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and

the Institute for Computer Sciences and Technology.

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research and provides scientific and technical services to aid Federal agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and

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'Headquarters and Laboratories at Gaithersburg, MD, unless otherwise noted; mailing address Washington, DC 20234, 'Some division? within the center are located at Boulder. CO 80303.
National Bureau of Standards NBS/RIA Robotics Research Workshop

noi. xcc. . ^e~f^

Proceedings of the NBS/RIA Workshop on Robotic Research, US']

Held at the National Bureau of Standards in , Gaithersburg, MD,on November 13-15, 1979 - ^'^^

Edited by:

James S. Albus, Gordon J. VanderBrug,

Anthony J. Barbera, M. L. Fitzgerald,

and Thomas E. Wheatley

Industrial Systems Division

Center for Mechanical Engineering

and Process Technology

National Engineering Laboratory

National Bureau of Standards

Washington, DC 20234

Sponsored by

The Robot Institute of America

20501 Ford Road

P. O. Box 930

Dearborn, Ml 48128

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued April 1981
Library of Congress Catalog Card Number: 80-600192

NATIONAL BUREAU OF STANDARDS SPECIAL PUBLICATION 602

Nat, Bur, Stand. (U,S.), Spec. Publ, 602, 54 pages (Apr. 1981) CODEN: XNBSAV

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1981

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Price $3.75

(Add 25 percent for other than U.S. rnailing)
TABLE OF CONTENTS

I. INTRODUCTION 1

Address List of Workshop Participants 3

II. DISCUSSION GROUPS 5

1. Assembly 6

2. Control Systems Architecture and Implementation 8

3. Robot End Effectors 12

4. Welding 14

5. Programming Languages 17

6. Manufacturing Systems 20

7. Inspection Systems 24

8. Touch and Force 27

9. Vision I 29

10. Vision II 33

III. DELPHI FORECAST 34

1. Introduction 36

2. Sensors 36

3. Control 44

4. Market - . 48

5. Research Properties 49

iii
ABSTRACT

The NBS/RIA Robotics Research Workshop had two objectives: 1) To

provide a forum for structured discussions between researchers in

robotics and manufacturers and users of robot systems; and 2) To

develop a consensus forecast of future developments in sensors and

control systems for industrial robots.

The Workshop brought together 31 researchers, manufacturers, and users of industrial robots in order to determine the needs and

priorities for future research in sensors and control techniques

for industrial robots. There were no formal papers; instead,

small group discussions and presentations and the preparation of

a Delphi Forecast were used to address research needs and prioritie

Key words: Delphi Forecast; robotic control; robot vision; robotic

assembly; robotic standards; robotics research.

iv
I. INTRODUCTION

On November 13"i5» 1979« a Workshop on Robotics Research uias

held at the National Bureau of Standards in Gaithersburgi

Maryland. The Workshop^ which was arranged by the National

Bureau of Standards in cooperation with the Robot Institute

of America/ had two objectives:

1. To providt a forum for structured discussions

between re&earchers in robotics and manufacturers

and users oP robot systems; and

2. To develop a consensus forecast of future developments in sensors and control systems for industrial

robots.

The Workshop brought together 31 researchers* manufacturers/ and usei& of industrial robots in order to determine

the needs and priorities for future research in sensors and

control techniques For industrial robots. There were no formal papers; instead/ small group discussions and presentations and the preparation of a Delphi Forecast were used to

address research needs and priorities. The purpose of the

report is to document the proceedings of this Workshop.

Attendees were split into 10 small groups: assembly/ control systems/ end effectors/ welding/ programming language/

manufacturing systems/ inspection/ touch and force sensors/

vision 1/ and vision II. There were two vision groups because of the intense interest in this area. The results of

these small group discussions are presented in Part II of

these Proceedings.

A Delphi Forecast on needs and priorities for sensor and

computer control technologies was prepared by the participants. The first round was prepared prior to the Workshop

and was discussed the first evening. The second round was

prepared the morning of the second day/ and discussed that

same afternoon. A third round was then prepared and turned

in at the end of the meeting. The results of the third

round are presented in Part III of these Proceedings.

Key conclusioni> that can be drawn from the Delphi Forecast

are:

1. Sensor -c ontrol led movements of robots appear to be a highly desirable feature for present and future applications of robots. The most immediate economic

benefit tuds simple vision in most application areas.

The second most valuable sensory capability was different For different applications; proximity was

-1-
second for spot welding and arc uielding; simple and

complex force for drilling/ routing* and grinding;

complex vision and simple force for assembly; and

touch for machine tool and press load/unloading.

2. Robot users felt that a cost of more than $10i 000

could be justified for simple vision; less than

$41 000 for proximity* simple force* and touch; and

about 4»23* 000 for complex vision.

3. There tuas a strong consensus among all participants

that simple vision is the first priority for

research and development efforts.

4. All sensory capabilities* including complex vision*

should reach commercial availability before 1985

with at least 10 per cent of robots shipped that

year having at least one of the listed sensory capab i 1 i ties.

5. For all the applications addressed* the position and

orientation of the majority of uiorkpieces are known

to within plus or minus one inch and plus or minus

20 degrees. In most cases* this is within the capabilities of simple vision systems.

6. Line following would be highly useful only for spot

welding. However* robot mobility (the robot mounted

on a platform which can be moved about allowing the

robot to operate in many locations) would be useful

in over 20 per cent of all applications. The exception was small parts assembly.

7. A shift was seen during the 1980's from the pointto-point control systems to systems with coordinate

transformation* off-line programming* and trajectory

op t imi zat ion.

8. By 1990 25 per cent of all robots shipped will be

incorporated into computer-aided manufacturing systems.

9. The market for industrial robots in 1985 is estimated to be approximately $225 million* and $780 million in J790. This represents a projected growth

rate of about 30 per cent per year.

-2-
ADDRESS LIST DF WORKSHOP PARTICIPANTS

James S. Albus

Programmable Automation

National Bureau of Standartls

Bldg. 220, Rm. A123

Washington, DC 20234

Anthony J. Barbera

Programmable Automation

National Bureau of Standards

Bldg. 220, Rm. A123

Washington, DC 20234

Richard C. Becker

Chesebrough-Ponds, Int.

John Street

Clinton, CT 06413

John Birk

University of Rhode I&lcind

Electrical Engineering Dppt.

Kingston, RI 02881

Nelson Corby, Jr.

General Electric Co.

1 River Road

Bldg. 37. Rm. 561

Schenectady, NY 12341,

G. E. Ennis

McDonnell Douglas

P. 0. Box 516

St. Louis, MO 63166

D. W. Evert

Aluminum Co. of Americia

Alcoa Laboratories

Alcoa Center, PA ir>069

Dan Fitzpatrick

Prab-Ver satran

5944 E. Kilgore

Kalamazoo, MI 4900J

Brian Ford

ASEA Inc.

4 New King Street

White Plains, NY 10604

Joseph B. Gibbons

General Electric Co.

1 River Road

Schenectady, NY 1234r.

R. J. Handuierg

General Dynamics

Box 741, MS 5457

Fort Worth. TX 76101

Richard E. Hohn

Cincinnati Milicron

4701 Marburg Avenue

Cincinnati, OH 4524;'

Floyd M. Holroyd

General Motors Manu. Dpvt- 1 opment

Tech Center

Warren, MI 48090

Riley Kuehn

Boeing Commercial Aitplfine Co.

P. 0. Box 3707, MS 9H 53

Seattle, WA 98124

James H. Lockett

Northrop Corporation

3901 W. Broaduiay

Hawthorne, CA 90250

C. D. Mathes

General Dynamics

P. 0. Box 748

Fort Worth, TX 76101

Norman Maxey

Deere & Co.

John Deere Rd.

Moline. IL 61265

Ward V. McClure

Texas Instruments, Inr.

P. 0. Box 225621

MS 452

Dallas, TX 75265

Lori D. Mei

Society of Manufacturing Engineers

One SME Drive

P. 0. Box 930

Dearborn, MI 48128

Roger N. Nagel

Programmable Automation

National Bureau of Standards

Bldg. 220, Rm. A123

Washington, DC 20234
Ronald D. Potter

Robotics Technology* Jru . 150 Technology Par k/At) anta

Norcross. GA 30092

Daniel J. Reinhart

Caterpillar Tractor Co.

600 \fi. Washington St.

E. Peoria. XL 61560

Peter Rogers

Unimation« Inc.

Shelter Rock Lane

Danbury« CT 06B01

Victor Scheinman

Stanford University

523 Hillside Dr.

Moodside. CA 94062

Robert N. Stauffer

Robotics Today Magazine

One SHE Drive

P. 0. Box 930

Dearborn* MI 48128

Milliam R. Tanner

Tanner Associates

P. 0. Box 279

Farmingtoni MI 480I?4

Gordon J. VanderBrug

Programmable Automation

National Bureau of Standards

Bldg. 220, Rm. A123

Uashington> DC 20234

Philippe Villers

ComputerVision

201 Burlington Rd.

Bedford, MA 01742

Mitchel R. Ward

General Motors Research l.abs.

General Motors Technital Center

Warren, MI 48090

Peter M. Will

International Businpns Mcichines

P. 0. Box 1328

Boca Raton, FL 3343?^

Domenic A. Zambuto

GTE Laboratories, Int.

40 Sylvan Rd.

Waltham, MA 02154

-4-
II. DISCUSSION GROUPS

Each participant u)a& assigned to two groups on the basis of

his or her expressed interest. Five groups met the morning

of the second dai{« and five met the morning of the third

day. These groups directed their efforts toward identifying

and quantifying as much as possible the principal research

issues related to their particular group topic. After these

individual meetings* all of the participants were brought

together. A spokesperson for each group presented a summary

of the consensus view of the group's discussions. This allowed all of the participants to review and contribute to

the central points identified in the smaller groups.

The chairperson of each group* assisted by a scribe*

prepared a written summary which is reprinted here.

-5-
1 . ASSEMBLY

Group Members:

Mard McClurt - Chairperson^ Texas Instruments

Joseph Gibbons - General Electric

Mitchel Ward - General Motors

Floyd Holroyd -- General Motors

Peter Rogers - Unimation

Phil Villers - ComputerVisi on

Robert Stauffer - Robotics Today

Peter Will - International Business Machines

Gordon VaridrrBrug - National Bureau of Standards

A. Introduction

The application of robots to the assembly of products continues to be exceedingly difficult; houieveri some progress

is being made. Assembly is recognized as being one of the

last frontiers for automation of small-lot> batch manufacturing operations. At present* product assembly is primarily a manual task. In order to be successful in this areai

any machine or set of machines will be required to perform

jobs bihich are generally today designed for people. These

jobs utilize the persons' abilities of sensing* implicit inspection* dexterity* common sense* reasoning* and relatively

easy trainab i 1 i ty

.

B. Group Report

The following is a summary of the issues discussed and conclusions reached by the assembly group:

There are tuto basic assembly categories. They are:

- Loose assemblies (loose tolerance and unfastened)*

- Close tolerance ( peg-in-the-hole type assemblies).

The majority of assembly applications in industry are loose

with tolerances typically greater than .005 inches.

Work is required in the identification and evaluation of alternative system configurations of feeders* robots* material

handlers* etc.* with respect to an optimization criterion

(usually cost per part).

Academic and applied work is needed on: - The design oF parts for assembly.

- The design of products for assembly.

-6-
- Robot-compatible parts presentation.

- Parts inspection in the broadest sense.

It was felt that the primary robot technology required consisted of machines with effective cycles of 2 to 6 seconds

and .25 mm (.010 inches) accuracy. This speed and accuracy

is available cofmer ical ly today (1979).

Economic justification is still based upon a 1-2 year payback criteria because versatility across basic applications

bountfaries has not yet been demonstrated.

A theory of error recovery needs to be developed* e. g. > an

error is recoverable if it can be detected before it can be

no longer disassembled.

Contact sensors slow humans and machines: The use of noncontact sensors is recommended where possible.

Disagreement still exists concerning the desirable number of

degrees of freedom needed for product assembly. The consensus was that for most products 4 degrees are sufficient;

however present robots need 5 degrees to provide a correct

implementation.

Limp parts such as wire and cables have not received enough

attention.

A special grade oP parts (close tolerances and 100 per cent

fit-foT— intended -use ) would be desirable to minimize line

downtime due to defects entering the system.

Very fast inspection devices are required so that a 100 per

cent inspection policy can be specified in lieu of or in addition to the automation grade of parts.

Insufficient attention has been paid to the problem of

training users to program/ operate* and maintain robots.

Fasteners cause problems in practice due to feeding* quality* and variety.

Simple vision integrated with a parts conveyor has much to

offer in parts feeding.

Assembly* while still not widely developed* is much brighter

in outlook than was concluded in the 1977 Delphi. Substantive application issues are being explored and the detailed

deficiencies of existing tools* feeders* and other auxiliary

equipment are being exposed as the area gains maturity and

is approaching practical development.

-7-
2. CONTROL SYSTEMS ARCHITECTURE AND IMPLEMENTATION

Group Members:

Domenic Zambuto - Chairperson^ GTE Laboratories

Tony Barbera - National Bureau of Standards

Jerry t.nnis - McDonnell Douglas

Riley Kuehn - Boeing

Richard Handuierg - General Dynamics

A. Introduction

It is very difficult to define or agree upon what would be

the most appropriate control system architecture for integrated robot sy&tcms. This problem has been studied by the

academic community^ research inst itutions< and a number of

industrial research laboratories. Each has developed their

own architecture and programming languages.

A number of users of industrial robots in this country are

upgrading the robot control system to interface with sensorsi special devices (jigs> fixtures^ etc. data base systems/ and other environmental conditions within their

plants. This is done« in some cases< at the expense of not

using the control system provided by the robot manufacturers

because it did not produce the user-desired capability^ or

because the source code was not available from the robot

supp 1 ier s. The unanimous conclusion of the group< was that there is a need to develop a "Standard Interface" for industrial

robots.

B. Group Report

The control group discussions focused on those attributes

needed to improve the capabilities of today's industrial

robots so that they can function in less structured environments.

Today's industrial robots function in constrained environments» performing their tasks by moving through pre-recorded

sets of spatial points in a sequential manner. These programmed points are taught by leading the robot through the

desired task and recording the joint positions along the

way. In many applications/ particularly those which require

frequent changes/ such as batch manufacturing/ this type of

activity can be very time-consuming and undesirable. However* with the coming of the low-cost microcomputer technology/ more powerful robot control systems may be configured.

Thus/ research is needed to define and develop the robot

-8-
control system architecture in which processes can be carried out in parallels in real time* and be sensory interactive uiithin the robot's environment.

With this in mind« the group discussed and created a list of

some of the desirable attributes of an advanced control system.

These were:

1. The control system should be modular and easily

expandable. There should be clean interfaces

between modules.

2. There should be easy communications betuieen

modules within the control system as well as

with other sensors and devices operating within

the environment of the robot.

3. The control system should interface with other

data ba&e systems so that robot programs can access part dimensions.

4. The control system should be easily maintainable

through the use of self-diagnostics and selfcalibration. In advanced systems it might even

interface with manufacturing maintenance centers

to dispatch maintenance personnel.

5. There should he a user-oriented high-level programming language which allows the programming

of the robot through simple English-like command

language. This language should be extensible;

that iSi it should allow for changes in input

commands* control algorithms/ sensors* and special devices. It should be possible to make additions and deletions with a minimum effort.

6. It should have off-line programming capability.

This will be required to develop the robot's

mainline (task) program without tying up the

robot hardware system. This capability will aid

in the integration of the robot into total

computer-aided manufacturing systems. It is

recognized that today's robots are nonlinear*

and in off-line programming* this nonlinearity

becomes a problem. A suggested solution is that

each robot have a positioning calibration file

that accounts for the non-linearity.

7. The control system and programming language

should be independent of the robot

-9-
conf i gurat ion» enabling its use with any robot.

This notion of a general purpose control system

and language should improve the portability of

the control systems.

B. The control system should provide trajectory optimi7dtion. The group . touched on this briefly by

discussing the ongoing work at Purdue University. It was felt that adaptive optimization

schemes needed for coordinated motion of robot

joints based on a predefined path between two

poiTits will be extremely useful for future robot

systems.

9. Therp should be obstacle avoidance and coordination control between multiple robot or other

equi pment.

10. There should be a floating zero reference so

that a programmed robot task at a defined reference could easily be translated to perform the

same ta&k starting at a different reference.

11. There should be the capability to switch the

servo -c ontrol function (under computer control)

from a positioning servo to a force-torque servo.

12. It was felt that there exists a need to establish a "standard interface" for industrial

robots. Figure 1 shows an interface between a possible real time control system and the robot.

Many isvues were raised during the group discussion on the

possibility oP a standard interface. For example/ one such

question addressed how position commands from the real time

controller would interface with the robot. Another such

question was where the coordinate transformation function

would be located. Many other issues were raised and the

only conclusion formed was that it is a difficult problem to

define and that possibly NBS-RIA might* together with the

National Science Foundation* Electronic Industries Association* and the American National Standards Institute* initiate action on defining and establishing a "standard interface. "

-10-
ROBOT LANGUAGE INTERFACE

SENSORS

SPECIAL

DEVICES <^

C==> POSSIBLE

REAL TIME ROBOT

CONTROL SYSTEM

INTERFACE

USERS DATA BASE SYSTEM

LINE ROBOT INTERFACE BUS

- For Position & Function

Commands

- For Position & Function

Responses & Robot Status

FIGURE 1

POSSIBLE ROBOT SYSTEM INTERFACE

-11-
3. ROBOT END EFFECTORS

Group Members:

Dan Evert - Chairpersorii Aluminum Co. of America

John Birk • University of Rhode Island

Jim Lockett - Northrop Corporation

C. D. Mather - General Dynamics

Ron Potter - Robotics Technology Inc.

Victor Scheinman - Stanford University

A. Introduction

For discussion purposes* the subject of end effectors was

divided into two general application areas. For the most

part/ the needs in the two areas are different. The two application areas were: (1) part handling and (2) tool hand 1 ing.

B. Group Report

The expressed need common to both categories of end effectors was standardization of an interface adapter with

quick-change capability. It was recognized that more than

one size of standard adapter would be required to accommodate the wide range of robot sizes. In part handling applications/ the quick-change adapter will facilitate the handling of a wide variety of part geometries where several

gripper configurations are used and must be interchanged

frequently. In applications where the robot arm is being

used to quick-change tools for drilling/ tapping/ and milling/ a quick-change tool adapter would enable one robot to

perform a variety of machining operations with minimum time

required for tool change.

The standardized features of an interface adapter should include the following:

1. Mechanical connection providing a common mounting and securing system for all types of end effectors.

2. Electrical connection to provide an interface

for electrical power and electronic signals to

the end effector and electronic signals from

end -effector-mounted sensors.

3. Hydraulic connections to the end effector for

hy draul i cal ly powered actuators.

-12-
4. Pneumatic connections for pneumatically poiuered

actuators.

All of the above interface connections should be the type of

automatic connections which permit automatic tool changing

when called for by the robot's control program.

The discussion of research and equipment development needs

in the area of part handling end effectors centered around

the idea of universal applicability. The assertion was made

that there are few shapes which cannot be grasped by simple

parallel jaw grippers. Hand pliers or tongs were offered as

evidence supporting that statement. It was concluded that

research work should be directed toward developing sensory

systems to provide the intelligence needed for a robot to

utilize this simple gripping mechanism effectively.

Special needs in the* area of tooling type end effectors were

discussed. It was pointed out that many of the tools used

by robots for operations such as drilling* routing* milling*

and grinding are designed around the adaptation of available

hand tools. As such* these adaptations result in unsatisfactory performance* causing excessive deflection and

chatter in many machining applications. To remedy this* a line of tools should be developed specifically for use by

robots. These tools should be lightweight* compact* and rigid.

Additional work in the ar&a of sensory feedback in machining

applications is nc-eded. Edge tracking and force sensing

capabilities were cited as examples.

The subject of end effector dexterity was discussed briefly.

Part reorientation in the hand to minimize robotic transfer

cycle time requires a far more dextrous gripper than is

currently available. End effector dexterity was also seen

as a way to improve the overall robot/gripper system accuracy and repeatability. Fine movement of the end effector

could "zero in" on positioning requirements outside the

capabilities of the robot's hardware alone.

-13-
4. WELDING

Group Members:

Norman Maxey - Chairperson^ Deere & Company

Dan Reinhart - Caterpillar Tractor

Dan Fitzpatrick - Prab-Ver satran

Dick Hohn - Cincinnati Milacron

Brian t-ord - ASEA

A. Introduction

The welding discussion covered both resistance uielding# spot

uelding/ and gas-metal arc welding. Due to constraints on

time< arc welding was discussed in greater detail than

resistance welding.

Arc welding is a process which joins two or more pieces of

metal through fusion. Metal Inert Gas <MI6) welding was the

arc welding process on which the group concentrated! largely

because this wat the process in which the participants had

the most knowledge and experience.

Problems associated with arc welding are largely due to inconsistant joint fitup. Joint location and gap vary from

part to part due to inconsistent cutting and forming operations. A human welder will vary welding parameters and the

welding method to adjust for these variations. Today's

robots will not automatically adapt to part variations.

Spot welding a process used for joining two or more

pieces of sheet metal together with resistance heat. Spot

welding of automobile bodies is a typical use of this form

of welding. Robots are used to carry spot welding guns to

the workpiece. The workpiece is usually fixtured and in a known position in relation to the robot.

B. Group Report

MIG welding was the first process discussed. Deere and Caterpillar generally agree that the following are their reasons for reviewing robotic welding:

1. Integrity and/or quality of welds.

2. Productivity and environmental problems.

3. Weld appearance.

Joint location and gap variations are the biggest problems

associated with robotic MIG welding. The joint location and

gap problems are different for various metal thicknesses.

-14-
This group> thcrpfore^ broke the discussion into tuio categories - 1/4" and thinner sheet metal and thicker than

1/4" plate steel.

Folloiiiing is a Ixf^t of problems and conclusions the group

felt were associated with the 1/4" and thinner sheet metal;

1. Joint location is the most significant problem

associated with lighter sheet metal parts.

2. A non-contacting sensor is needed.

3. Vertical torch adjustment is less critical to

the process than traversing adjustments.

4. The small weld size used with this gauge metal

makes high robot accuracy and repeatability

essential.

5. Sensor feedback adjustment should control 2 or

more degrees of freedom.

6. Vision is the most desirable sensor control for

robotic welding.

7. Sensors should be placed just ahead of the welding arc.

The problems and conclusions associated with the heavier

than 1/4" plate steel are the same as above* with the following additions:

1. Sensory control for 2 or more degrees of freedom

plus compensation control for gap variation is

required. This automatic compensation should

include wire feed change* voltage ad justmenti arm

travel speed* weave capability* etc. The welding parameters should be changed automatically

as conditions change.

2. Robot accuracy and repeatability are important*

but not as critical as for the sheet metal welding. Ihe heavier welds allow for greater tolerances in point of arc placement.

The manufac turerf. stated that the sensor need* to some extent* is being addressed now. Each welding robot manufacturer is approaching the problem in a manner which they feel

will satisfy the users' need.

However* it was felt that the present effort is not on a large enough scale and additional effort should be started

-15-
in the area of sensor-controlled arc welding. The research

should be at least on the scale that assembly is being investigated today. Uelding is an environmentally undesirable

production procfr't>s which is essential to American industry.

More than 65 million worker hours and 540 million pounds of

wire are expended on MIG and Tungsten Inert Gas (TIG) welding each year in the United States. Adaptive control

through the use of sensors would allow for wide usage of

robots for welding by American industry. There is a large

potential productivity gain to be acheived in this area.

The group only knew of one research institution with an

ongoing research project using sensors for welding robots.

Stanford Research Institute (SRI) is attempting to develop

vision for welding robot control.

Spot welding as it is commercially available today is widely

accepted by American industry. Sensors could be utilized if

they were developed/ but they are not as essential for spot

welding as for gss-metal arc welding. If sensors were to be

developed/ proximity sensors and vision would be the most

valuab le.

C. Additional DiscuDsion

Mobility in a robot would satisfy a limited need. Some need

exists for a robot which would weld from more than one station on a single Isige fixture. More benefit would be realized if a robot could move from one location to another*

which would allow f^or welding on more than one fixture. A

robot used in these applications should be non-servo controlled for movement between locations.

Sensors should be &mall enough to allow access to small confined areas.

Parts must be designed to allow for automation. Manufacturing tolerances on simple parts must also be controlled so

that subsequent welding processes can remain largely unchanged from part to part.

Research associated with automatic process control must be

conducted. When the sensor indicates that a change has occurred in the part joint* the control must know what welding

parameter to modiPy (wire feed* voltage* weave* robot arm

speed* call operator* multiple pass* etc. ) The logic associated with these changes must be established.

-16-
Ik programming languages

Group Members:

Mitchel WtsT-d - Chairpersoni General Motors

Richard Hdndujerg - General Dynamics

Dick Hohu • Cincinnati Milacron

Dan Reinhart - Caterpillar Tractor

A. Introduction

Language is the means by which a user communicates to the

robot system thr actions to be performed. Historically^ a robot has been "taught" a path. Using a "teaching pendant"

the robot was moved through the desired path and the required setpoints were recorded for future playback. With

the increasing sophistication of robots and their applicationsf this teaching method has evolved to a more complex

procedure of first laying out a nominal path< then using

both a teaching pendant and a keyboard-type device for

entering the path logic< functional description/ and setpoints.

This group directed their discussion toward the environment

of the robot programmer and to general areas of future

development within robot languages. Specific languages or

language construrts were not addressed.

B. Group Report

The first topic addressed was to clarify some of the terminology. There wfs& general agreement that with today's

robots* "programming" and "robot program" are technically

more accurate terms than "teaching" and "robot path" respectively* although the- terms are generally used interchangeably.

Programming is a) establishing the logic and functional

description of a program and b) specifying the required

data. The combination of logic and data is a program. The

required data mf;y be established by teaching/ as is widely

done today/ or may be provided by an external source such as

a sensor or a data base.

The second issue wai- the question of who does the programming. There was general agreement that in the future robot

programming will he done by people comparable to today's NC

(Numerical Control) programmers. In certain application

areas such as welding/ these programmers would first need to

be experts in the process being performed by the robot and

-17-
secondly computer programmers. Houiever« there is a definite

need for the oprrator on the production floor to be able to

"touch up" a program.

The final topic discussed was that of what general areas of

language development should be addressed by researchers and

manufacturers today. The following areas were discussed:

1. Off-line programming is the process of creating

all or part of a robot program without using the

robot directly (using a spare robot for program

development is not off-line programming as defined here). As the logic development phase of

robot programming continues to growi more of the

techniques of computer programming are needed to

support the development of robot programs. Keyboard entry and editing of programs and data«

program listings/ and simulated execution of

programs are examples of features which should

be generally available.

2. Integration of sensor capability into robot

languages is an important consideration. A general theme of this workshop was the importance

of sensors in robot applications. Wide usage of

sensor 'based robot systems requires the integration oP constructs into the robot language for

using these sensors.

3. The need to access geometric data bases is

becoming more desirable. As more industries

maintain computer data bases which describe the

geometry of parts and assemblies/ the need for

an interface between the robot language and

these data bases grows. These data bases can be

used almost directly to provide data such as

hole locations/ or they can be used indirectly

to provide data to support high-level assembly

taskfi.

4. Support for creating and maintaining program

data bat/es is a growing need. This computerized

data bttse would be a replacement for the

cassette tapes of today. This central data base

would require the ability to download line programs From the data base to the robot as well as

to upload programs from the robot into the data

base. This general support would eliminate the

need foi- special devices at the robot station

for program loading and would greatly simplify

the operator interface for program loading/

touchup and backup. Automatic program loading

-18-
based on part identification or sensor input

would be possible.

This group did not consider the above to be a complete listi

but rather* these were the topics discussed during the time

available.

C. Additional Discussion

Following the group report to the full workshop* several

other issues were raised.

There is a need for some standardization of robot terms.

NBS responded that they are planning to produce a set of definitions next year.

The question arose as to whether there should be a family of

languages for robots where each language is tailored to a class of applications. At the other extreme was the question of a general manufacturing language for programming a complete application. The robot language would be a subset

of this general language.

The question was raised as to whether a level of language

standardization comparable to the APT CLTAPE files should be

developed. There was general agreement that this was desirable and that at least the research community should begin

pursuing this question.

-19-
A. MANUFACTURING SYSTEMS

Group Members:

William Tanner - Chairperson^ Tanner Associates

Richard Becker - Chesebrough-Ponds

Jerry tnnir. - McDonnell Douglas

Dan Fitzpatrick - Prab-Versatran

Norman Max(*i| - Deere & Company

Ron Potter • Robotics Technology Inc.

Others in attendance:

Lori Mei " Society of Manufacturing Engineers

Brad Smith - National Bureau of Standards

Robert Steuffer - Robotics Today

Gordon VanderBrug - National Bureau of Standards

A. Introduction

The session was opened with an attempt to define a manufacturing system. After some discussioni the consensus was

that a manufacturing system might be defined as: "Men> materials/ machines* and processes combined to make a product. " In the context of the workshop/ it was decided that

"robots" should be substituted for "men" in this definition.

B. Group Report

It was felt by mo&t of the group that manufacturing systems

could be classified as "simple" or "complex. " From this

point/ the elements of a simple manufacturing system were

identified. These were:

Machines

Controls

Material movers

Robots

Interlocks

In a simple or "ntand-alone" manufacturing system/ the level

of integration of these elements is very basic. Often there

is no central control/ each element of the system contains

its own control capability. An overall management function

is still necessary/ however/ and this is usually vested in

the robot. "Ihrough simple interlocks/ such as hard wired

links between controllers/ the robot initiates the actions

of the other elrments of the system at appropriate times.

Execution and termination of these actions are handled by

each element's own control/ which then returns signals to

the robot.

-20-
It was felt that current state-of-the-art technology is sufficient to support simple manufacturing systems. In fact/

many examples of such systems exist today* from die castquench-trim and multiple machine tool loading-unloading to

multiple station tooling/conveyor/robot systems for automobile spot welding.

The discussion then turned to complex or integrated manufacturing systems. Complex systems contained the same basic

elements as simple systems* plus interfacing* monitoring*

and supervisory control. A complex manufacturing system

might* in fact* be made up of a linked group of simple

manufacturing systems* operating as manufacturing cells. A

control hierarchy is involved* with several functional levels* as diagramoted below:

Scheduling

CAD/ CAM

Work In process

Inventory data

WORK

STATION

CONTROL

W/S ELEMENTS

W/S ELEMENTSW/S ELEMENTS

W/S ELEMENTS

W/S ELEMENTS

Simply described* this hierarchy functions as follows: Each

Work Station (WB) in this diagram corresponds to a simple

manufacturing &y<>tem* with one exception; the existence of

an overall or supervisory control* the Work Station Control

(WSC). The individual WS's are linked* through their WSC's

to the Center Control (CO. The CC monitors each WSC and

schedules the materials and operations for each US* based

upon input from the Job Shop Control (JSC). The CC also

transmits data regarding production* US availability* etc.*

to the JSC. Thf JSC is responsible for supervising* coordinating* and monitoring all operations in the shop through

several CC's. I he JSC is also responsible for production

-21-
planning and scheduling and for development of management

information. Thus* there are inputs to the Job Shop Control

from sources other than the shop floor. CAD (Computer-Aided

Design)* CAM (Computer-Aided Manufacturing)* MIS (Management

Information Sy?item&)* and group technology may all contribute information to the Job Shop Control.

It was determined that feu* if any* complex or integrated

manufacturing sy&tems exist today to the level described.

Several factors inhibiting growth of manufacturing systems

to this level uit^rc presented: economics* lack of documented

experience* lack of systems development sources, and lack of

systems vendors. Interestingly* technology was not cited as

a major inhibiting factor.

The discussion wa<> then directed to the technology and

hardware needed to facilitate complex manufacturing systems.

Having determined that technology and hardware were not

holding back the development* the purpose was to determine

what* if any* technology might encourage complex manufacturing system development. One factor which might apply was

the enhancement of robot capabilities through development of

vision systems* control systems* end effectors* sensors other than vision* piogramming * and control languages. In

short* all of the items under discussion in other small

group sessions would be integrated into manufacturing systems* both simplr and complex.

Another robotic need identified was the need for increased

interface capabilities* particularly with host computers.

High-speed data interfacing* ability to download entire programs* ability to download while in program execution*

standardized interface ports and data structures* multiplexed inputs and outputs were felt to be areas of deficiency in present robot control systems. It was felt that

development of these capabilities should be accomplished by

the robot vendors, t ittle basic research was necessary in

this area.

Basic research* according to the group* should be concentrated on the architecture of complex manufacturing systems.

One significant need is for a "cookbook" or "handbook" to

guide users in the planning and development of complex

manufacturing syr.tems. Universality of programming language

and data base structure were considered to be extremely important. Another basic research area should be the development of monitoring systems* including sensors and software

capable of not only detecting problems and initiating shutdown* corrective or alternative action* but also capable of

predicting breakdowns and initiating preventive actions before they occur. Another need is for group technology

methods which are applicable to small-batch manufacturing.

-22-
In summaryi the group felt that the current state-of-the-art

is adequate to permit continued implementation of simple or

stand-alone manufcic tur ing systems. However* development of

complex or integrated manufacturing systems will not proceed

at a rapid pace in the near future/ due to economics/ lack

of experience/ and lack of knowledge in the structuring and

implementation of such systems.

-23-
V. INSPECTION SYSTEMS

Group Members:

Roger Nagel - Chairperson/ National Bureau of Standards

Nelson Corby ~ General Electric

Brian Ford - ASEA

Floyd Holroyd - General Motors

Riley Kufhn - Boeing

Ward McClure - Texas Instruments

Peter Mill - International Business Machines

Russ Young - National Bureau of Standards

Dominic Zambuto - GTE Laboratories

A. Introduction

The inspection area uias found to have five separate subtopics biith increasing complexity based on inspection data.

They are, in order: dimensional tolerances^ surface quality^

part integrity (uihich was considered to be a catchall)* material quality* and functional test. For discussion purposes* explicit ond implicit inspection were defined as follows:

Explicit in&pection is the performance of a required

inspection ict&k.

Implicit ins.ppction is a manufacturing check which is

performed* or should be performed* as part of some

manipulation task.

There is a fundamental problem because common-sense manufacturing checks arr not documented as part of the processes

which are performed in manufacturing. This is compounded by

the fact that ppople cannot describe algorithmically the

process they go through in discovering errors and in doing

the implicit inspections as part of their tasks.

B. Group Report

The inspection group discussions centered on several topic

areas. The first of these were robotic considerations. We

need to know the effect of the weight of a sensor on the accuracy of a robot. We also need to know how an inspection

system can get accurate data independent of the robot. It

was pointed out that there is a need for a family of inspection robots to be designed and developed for that purpose.

In particular* it was suggested that the first such robot

have a 5- to 10- pound part capacity and that it be the size

of a bread box.

Research topics idrntified during the discussions were the

-24-
fol lowing

Fast complex vision

A micrometer or other measuring device in the hand or

the fingers of the robot

High precision* non-contact three-dimensional sensors.

Testing and in&pection of printed circuit boards.

A high-speed arm uihich moves to a high-precision end

point uihich is determined externally.

Determining the- completeness of parts* their orientation* location* the components present* etc.

Measuring and determining the gradation of surface finishes during an in-line process.

The following tasks were determined to be currently possible

with additional compute power as made available by microprocessors.

Combinations of simple sensor measurements* for example* the measurements being performed on car bodies by

Ford and Volkswagen.

Simple vision tasks such as counting holes that go

through or blind holes. Locating edges and corners.

Determining the* presence or absence of features such as

labels or other markings on the parts.

In general* it was felt that the problems which can be

solved at this point are those that require simple sensors*

and will be done by making a large number of measurements by

utilizing the compute power offered by todays microprocessors. Mhat is needed in the future are designs for inspection of parts* assemblies* robots* and sensors. It is felt

that inspection will be truly automated when each of these

items has been designed with inspection tasks in mind. A

major impediment to progress in inspection was considered to

be the lack of fundamental knowledge. It was recommended

that an industrial engineering group survey the manufacturing process for a sample application. Uith respect to the

chosen application* they should consider a list of steps involved in that mfmufac tur ing process* itemize what can go

wrong* determine what class of sensors would be needed* and

what automatic tasks can be performed. Uhen this knowledge

base has been collected* it would be important to analyze it

for commonalities* to group the tasks in families* and to

-25-
order thetn by complexity. It uias suggested that the NBS

would respond favorably to a request to perform this by the

Society of Manufacturing Engineers or other responsible

group.

It mas further postulated in a group discussion that approximately 20 per ceiii of the total manufactured output is either not inspected or poor algorithms are used. There is

room for improvement of productsi avoidance of value-added

steps« and a general increase in productivity by proper inspection techniques.

The group felt that future directions for inspection would

be toward in -process inspection> 100 per cent inspection*

and designs for in^pection. Me need quality functional

parts. We must avoid human inspection because of human

frailityi boredomi and the inappropr iateness of the task for

human beings.

Driving forces that will move us in the directions mentioned

above are the need for improved quality and produc tivi ty

>

government regulations* and the economics of discovering

after value-added steps that the product had a flaw at the

beginning. It wac> pointed out that the high cost of recall

programs experienced by automobile companies and others has

helped focus the need for in-process inspection and 100 per

cent inspection.

In summary* the group reached the following conclusions:

y@ need a robot family designed for inspection.

We need to conduct a manufacturing survey of the tasks

and problems involved in inspection.

We must move toward automatic inspection* in-process

inspection* and 100 per cent inspection.

There is a need to educate the practitioners about the

current state -of- the-art* so that they can use it now

and help it evolve to meet future needs.

-26-
8. TOUCH AND FORCE

Group Members:

Victor Schcinman - Chairperson* Stanford University

Joseph Gibbons - General Electric

C. D. Mathes — General Dynamics

James Albus - National Bureau of Standards

A. Introduction

The group discussions focused on definitions* directions*

and problems rather than specific applications or implementations. From an industry point of view* force or touch

sensing presently means the equivalent of LVDT's and springs

or microsufi tches on the gripper tips. This is force and

touch sensing of the simplest form. Obviously* further

development ujill occur. We felt that good definitions of

force and touch sensor categories are a must for further

discussion.

B. Group Report

Touch sensors tuould include both single and multiple binary

(contact) or proportional omni—d imensional force and/or displacement sensors intended for gripper or tool surface

mounting or placement where contact information is desired.

Force sensors would include simple devices to measure onedimensional force information while complex sensors would

include devices capable of measuring forces* moments* or

torques in multiple dimensions (up to 6 dimensions). Generally* these force sensors would be considered to be physically located away from the actual contacting end effector

surfaces* such as at the base of the fingers* between the

end effector and manipulator* at a joint* or in the robot

base. They could even be devices such as joint torque controllers relying on pressure or current measurement in the

actuators. We recognized the need for force- moment* and

torque information but found it difficult to describe applications in terms of force sensing to get the end results we

want.

Specific recommendations of the group include development of

a "touch camera"* and a gripper mounted unit which can map

the surface features of touched objects. Applications such

as the proverbial bin-picking problem abound* with a possible need greater than that of vision.

Further hardware and software developments are necessary*

especially in the area of increasing the resolution (larger

avvai} sizes* shapes* and increased density)* simplifying the

-27-
ufirirtgi and rugqpdizing the contacting sensor surfaces. i»

is also necessary to properly and efficiently correlate localized and partic«l feature sensing uiith computer models of

whole objects.

Force sensor development should proceed with improved sixaxis sensors having greater dynamic sense rangei greater uniformity of axis sensitivity^ and fully effective overload

protection. Ai-ray processors should be introduced to rapidly resolve the force and moment components. New algorithms

must be developed and implemented in software to effectively

interpret and employ the force information derived from

these sensors.

The subject of compliance was brought up during the workshop

discussion. In mcmy prototype contouring tasks such as

routing or grinding* passive compliance through low spring

rate flexure or spring-mounted tools has been effectively

used to implement simple force control or servoing. For

fast point to point transfer motions* compliantly mounted

end effectors must be locked in place to reduce oscillations. Uith respect to the remote center compliance device

(RCC)i a passive mechanical device which allows for accommodation or positioning error when mating close-fitting parts

(bearing insertion* dowel pin in hole* etc. )* the whole

group discussion concluded that it is not a sensor* but a tool or accessory because it is not an active device* nor is

there any active process directly associated with operation

of the device.

An alternative is active force servoing with compliance

developed through the sensor-computer-manipulator loop* in

which a structurally rigid manipulator is rapidly servoed on

force information generated by an active force sensor.

Although demonstrated in the laboratory* this approach has

not yet been implemented in industrial tasks. The discussion group felt thot more work on force control of robots

was necessary* and that the subject of active vs. passive

compliance or combinations required more study.

Early :i n the workshop section of the discussion* someone

made a conimtrnt that it seemed hard to believe that about 5

per cent of a proposed ideal research budget could be spent

on fcTufc and touch when microswi tches work well. As a result of the discussions* the Delphi forecast number was

increased to about 11 per cent. The key to further development and applications in the area of force and touch sensing

and control is describing problems and tasks in terms which

encourage the use of these sensor-based systems as alternatives to high precision tooling* ordered part presentation*

and defect-free tight tolerance components.

-28-
9. VISION I WORKSHOP

Group Members:

James Albus - Chairperson* National Bureau of Standards

Richard Becker ~ Chesebrough-Ponds

Nelson Corby - General Electric

William laiiner - Tanner Associates

Roger Nagel - National Bureau of Standards

A. Introduction

discussion on the outstanding

This question was broken down

- Types of App 1 i cat ions

- Training the Vision System

- Vision Sy«iiem Capabilities

- Interfaces between the Robot and the Vision System

B. Group Report

Types of applications

It was decided that the two most important applications of

robot vision were: a) determination of part position and

orientation* and b) inspection. In most cases* there is no

need to recogni2e what a part is. That is almost always

known. The real problems are: where is the part* what is

its orientation* and is it free from defects?

Giving a robot the ability to determine the position and

orientation of parts will greatly expand the number of robot

applications. Thc^re are relatively few applications where

parts can be prpi>ented to a robot with sufficient precision

that the robot ran blindly grasp them with no adjustment in

the pickup point. Parts feeders that present parts in precise position and orientation are expensive and often unreliable. Pallets or conveyors that can preserve part

orientation throughout the manufacturing process are not

practical in a large number of cases. It may be possible to

improve this situation somewhat in the future* but there

will always T-emain a large number of applications where

there are significant unknowns in position and orientation.

It seems likely that vision will be the most practical and

reliable means for the robot to acquire this information.

In many cases it is relatively simple to feed parts so that

they do not overlap or touch. When this is done* the vision

problem is vastly simplified. Often a simple silhouette

-29-

This workshop centered its

problems in robot vision,

into four problem areas:
binary image is adequate. Simple measurements on such an

image (like avva, first and second moments^ perimeteri and

major and minor axes) are all that is needed for robot part

acquisition.

Nevertheless^ at least two laboratories (Rhode Island

University and NDS) are actively working on vision systems

that can deal with touching and overlapping parts. The

strategy in both places is to split the problem into two

parts> using one f>et of vision algorithms to find and isolate a single part> and another set of vision algorithms to

determine its position and orientation.

Inspection is the second major application area of robot vision systems. Inspection is implicitly performed by human

workers every time a part is manipulated. Robot vision will

allow the robot to perform the same type of simple checks

for part integrity. Explicit inspection* of course* is itself a major area of application for machine vision whether

or not it is coupled with a robot. Human inspection* while

capable of much greater sophistication* is subject to error

due to fatigue* boredom* and distraction. The types of inspection discusF^ed were: verification of the number of

parts* verification of part type* verification of correct

labeling* and verification of the existence of holes*

threads* flanges* etc. It was felt that many of these types

of inspection tas^ks can be performed by robot vision systems

in the near future. More difficult jobs* such as measurement of dimensional tolerances* inspection of surface finish* and detection of cracks* chips* and scratches* are

still research topics.

Training the Vision System

From a user standpoint* the methods available for training

the vision system to perform a task are critically important. The simplest method for the user is a "train by showing" technique. Ihis implies that the vision system has

some internal method of selecting what features are important. Most vision systems currently available require a significant degree of user knowledge concerning the internal

workings of the processing algorithms. Many customers are

misled by vision "systems" which aren't really systems at

all. They are only hardware that customers must make work.

Most users do not have the expertise to turn this equipment

into reliable working systems.

In most installations there is a great deal of cut and try

required in adjusting lights* selecting appropriate

features* etc. Often* satisfactory operation of the vision

system is subject to parameters which may drift with variations in lighting. In order for robot vision to have wide

-30-
usage< a great deal of effort needs to go into design for

robustness and the development of turn-key systems which require very little user sophistication.

It was agreed that current vision systems are at a level of

technological development comparable to robots 15 years ago.

What is needed is for manufacturers to offer totally engineered systems like many robot manufacturers offer today.

It was felt that there is great opportunity for "vision system houses" to do robot vision systems engineering and to

market turn-key vision systems incorporating simplified user

interfaces and vision programming languages.

Vision System Capabilities

There was a great dral of discussion of the relative merits

of binary versus grey scale vision. Richard Decker noted

that Chesebrough -l-'onds used only grey scale in its inspection applications. Nelson Corby replied that General Electric used binary imcjges in most of their work. It was mentioned that General Motors has expressed to SRI the opinion

that there should be no more effort spent on binary images^

and that all Future systems work with grey scale images.

James Albus suggested that there is a middle ground where

the images to be- processed are binary* but that the threshold for slicing the image can be adjusted in a sophisticated way to discriminate the critical image features. Thresholds can themselves be images which may either be derived

from the camera or generated by the computer by algorithmic

processes. Roger Nagel pointed out that various techniques

of projecting structured light and analyzing the effects of

part translation or rotation can generate important visual

information. Often binary images resulting from these techniques contain more information relevant to manipulation

than can be obtained from much more complicated analyses of

grey scale images taken from a single viewpoint.

Interfaces Betweeii the Robot and the Vision System

Clearly* if the robot is to use information obtained from a vision system* thtrc* must exist an interface between the vision system and Ihc robot control system. There are three

types of information which the robot needs to be able to accept:

a) Branch on external condition. In this case* the vision systrm merely detects the presence of some condition which causes the robot program to alter its

behavior by executing a branch. This is the simplest

type of interface and is presently available on almost

all robots.

-31-
b) Go to a position and orientation defined by external

data. In this case« the vision system may compute the

position and orientation of a part and provide the robot

with this information. This requires that the robot

control system be able to substitute external data in

place of data already stored in its program. Most

manufacturers have some capability along these lines/

although the substitution process is often a very aiukuiard procedure. Many robot control systems do not

separate data from programs^ and many others do not have

any simple methods of substituting external for internal

data points.

c) Execute an incremental move based on external data.

In this case the vision system may compute the relative

distance between the gripper and the part to be acquired. Thit type of move is required for visual servoing. Ue are not auare of any robot that currently has

the capability for incremental moves in both translation

and rotation, although incremental translat ional moves

are possible on some models.

There is also a need for communication from the robot to the

vision system. "Ihe types of information that flow in this

pathway are commands to the vision system to take pictures;

parameters for lighting> thresholds* etc; instructions as to

what picture proccr.cing algorithms to employ; and even predictions or expected data based on what position the robot is

in or what phase oF the task execution is operative. The

robot control system may also ask questions of the vision

sy stem.

The issue of data formats and protocols for this robotvision system interface was raised but not discussed in any

depth. This iv. a large and important topic which will require much furtheT" study.

-32-
10. VISION II

Group Members:

John Birk ~ Chairperson* University of Rhode Island

Dan Evfrt - Aluminum Co. of America

Jim Lockett - Northrop Corporation

Peter Rogers - Unimation

Phil Villers - ComputerVision

A. Introduction

The following assertions mere supported by the group:

1. ThevE> is no fundamental reason why there

shouldn't be more commercially available equipment For vision.

2. In -house industrial activities in production

demonr^trate the technical feasibility of using

vision. More information is needed to judge

economic feasibility.

3. Three sources might develop vision: companies

who consider it a profitable business, robot

suppliers who can expand the range of applicatinn/ and robot users who want to save money.

4. There should be a closer coupling between industry «Tid universities. There are significant and

unnec f=?ssary delays for the use in industry of

what hai^ been developed in the universities.

5. A laige gap exists between commercially available* vision equipment and the capabilities

demonf.trated in the research community. This gap

needs to he, and can be# filled in the near future. There is a definite need to develop that

equ i pmen t.

6. Knowledge of orientation and position has

economic value. This value can be measured* for

example! by the cost of the most economic means

of regaining the lost knowledge and perhaps even

physically regaining the position and orientation.

7. There are many applications where vision is

nec esser y

.

8. Vision systems should aspire to many of the same

-33-
attributes as good armsi such as reliability'

loui c or-t« wide applicability' speedi and programmabi lity.

9. The importance of considering the entirety of a vision systemi including lighting/ harduiare> and

softu>are< a concept presented by the Vision I groupi was endorsed.

10. Vision hardware might more frequently be used in

robot installations if robot manufacturers approached vision hardware companies with a general lir>t of vision needs or if end users specified thtir needs to the extent required for total syr>tem development.

B. Group Report

Group discussion included the schedule for the introduction

of robots which could handle the bin-of-parts problem. It

was agreed that complex problems< such as bin picking< could

be made simpler technically by introducing various mechanisms* but this can lead to unacceptable costs. In generali

bin-picking robots might be expected to be introduced first

in slower cycle time applications. With time/ the number of

parts which can be presented from bins by robots will increase and the cycle- time will decrease. For low cycle

times/ multiple arms or hands which can reorient parts will

probably be necessary.

Group discussion aHo endorsed continued research on the

uses of a camera in the gripper and stereo vision. This

work was categorized as a medium-term industrial need. It

was decided that to list all the applications where vision

is necessary would have taken too long. It is probably possible to list generic categories of vision applications/ but

the group didn't work on this.

Joint discussion after the Vision II report first centered

on the need fctv a listing of who is doing research on

robots/ what are thc-y doing/ and what equipment is available. It was agieed that such a compendium was needed.

Some existing sources for this information are the Smithsonian Institution's Science Information Exchange and the

Illinois Institute of Technology Research Institute's report

on CAD/CAM antl Soc io-Technical Research. Forthcoming

sources of this kind of information are the new magazines

"Robotics Today" and "Robotics Age".

There was also a discussion of the major responsibility for

the introduction of vision in robot applications in industry. Generally it was agreed that users would play the most

-34-
important role. F<obot suppliers can be expected to contribute* mostly emphasizing simple vision with widespread applications. Vision systems can be expected to come from

other companies also. It was felt that having responsibility for a system consisting of a robot and a vision module

may pose problems since robot manufacturers uieren^t likely

to move into vision in a vigorous way and companies capable

of building vision hardware probably wouldn't want responsibility for an expensive arm. Another problem might be that

users would like to specify vision systems in terms of the

application objectives instead of the computational goals.

It was mentioned that vision was application specific. On

the other hand«. it also seemed likely that some components

of a vision system were generally useful and thus we might

expect the use of reasonably general systems which can be

tailored to different applications.

-35-
III. DELPHI FOKtCAST

INTRODUCTION

A list of 10 questions relating to sensors^ control system

capabilities/ and market predictions was distributed to the

participants bpPore the uorkshop.

The Delphi was conducted in three rounds. For the first

roundi the questionnaires were mailed to the participants

and filled out bcPore the workshop. These were discussed the

first evening* &n6 a second set of questionnaires was

prepared the ni'xt morning. This second round was discussed

the afternoon of the second day. A third set of questionnaires was then prepared and handed in at the end of the

workshop. The rcnults of this third round are presented

here.

For most answei-S/ the results are in the form of three

numbers. The first number is the arithmetic mean of all the

responses. The Tuxt two numbers are the cutoff values for

the upper and louier quartiles. For example* the responses to

a question invoJvint! the prediction of the year for an event

were summarized follows:

1985

1984-1987

Here/ the mean of a) 1 responses is the year 1985. The middle

50 per cent of the responses fell between the years

1984-1987/ while? 'db per cent of the responses were less than

1984 and 25 per cent were greater than 1987.

This questionnaire covered a large range of application

areas. The respondents were advised to fill in only that

part of the questionnaire that concerned the area(s) with

which they were most familiar.

SENSORS

Question la)

This question was concerned with the importance of different

types of sensors in terms of their immediate economic benefit for the user. This takes into consideration the cost for

the sensor in relcjtion to the relative increase in capability it might give a particular application. For example* consider spot welding of automobile bodies. The addition of

simple vision or proximity sensors could allow the robot to

accurately place the welds on cars carried by existing

transfer lines. This would eliminate the need of the additional expensive indexing and positioning equipment that

presently has to be installed for robots to perform this

-36-
task. Thus* thef>€> sensory capabilities received a high

ranking for spot welding because of the large economic benefits they would provide if available. In some app 1 ications«

such as press load ing/unload ing< none of the sensory capabilities received very high rankings. This reflected the

consensus that there is not much need for sensors in these

applications* or at least* that there is presently not much

immediate economic benefit to be derived from installing

sensors in these applications.

Comments on la)

In completing the questionnaires for the third time* the

participants were asked to provide written comments if their

responses differed significantly from the average values obtained in the second round.

There was significant disagreement on the value of sensors

for spot welding and press loading/unloading. Some of the

opinions expressed were:

"The use of sensors for spot welding and press

loading/unloading is largely unnecessary. Sensors will not

be applied if they slow down program execution. Cycle time

is critical in these operations.

"Spot welding is a well-accepted robot application even

without the use oP sensors. However* a proximity or simple

vision sensor which would ensure the proper placement of the

weld flange would be very beneficial."

"If one were building a spot welding line from scratch* the

economic tradeoff between sensors and fixturing would be

much more apparent than shown above.

"Simple vision enables the assembly being welded to be much

more coarsely positioned. This reduces transfer machine

costs and increasing the probability of a good weld. The

need for hand rework of defects is reduced.

"Simple inexpensive touch and proximity sensors are available today* and it would appear that there should be a much

higher immediate economic benefit when used in assembly than

the average shows. "

"An appropiate sensor for arc welding may be none of these

listed. The economic benefit that could be obtained with a sensor which could track the seam and change process parameters with the gap exceeds the economic benefits which could

be acheived with sensors in any application area.
SENSORS

la) Using the matrix belotu^ rank the listed sensors in

order of importance <1 through 6) for immediate economic benefit to the- user. Fill in only the rows that

correspond to the- application area<s) you are familiar

with. (You may give two or more sensors equal rank. )

1 ouch» Simp le

Force

Comp lex

Fore e

— — — — —

Proximity

Simp 1

e

Vision

Comp lex

Vision

Spot Melding 3. 7

(2-6)

4. 1 (3-5)4. 9

(4-6)

2. 1

( 1-3)

2. 1

( 1-2)

5. 4

(5-6)

Arc Uelding 4. 4

(4-6)

4. 7

(4-6)

5. 2

(5-6)

2. 5

(2-3)

1. 2

(1-2)

3. 4

(2-5)

Drilling* Routing

Grinding, etc.

4. 1 (3-5)

2. 4

( 1-3)

2. 9

(2-3)

4. 4

(3-6)

1. 8

( 1-2)

3. 9

(2-6)

Small Part

Assemb 1

y

3. 8

(3-5)

2. 6

(2-4)

3. 4

(3-4)

3. 9

(3-5)

1. 7

( 1-2)

2. 1

( 1-3)

Machine Tool

Load ing /Un 1 oad inc)

2. 8

(2-4)

3. 4

(3-4)

4. 6

(4-6)

3. 1 (2-3)

2. 3

( 1-3)

3. 6

(2-6)

Press

Load ing /Unload ing

2. 5

(2-3)

3. 1 (2-4)

4. 8

(4-5)

3. 0

(2-3)

2. 7

( 1-4)

« _ «.

4. 1 (3-6)

* Touch - presence or absence of parts or displacement along

one axi^

Simple force - measure force along a single axis

Complex force - me<»tiure force along two or more axes

Proximity ~ non -r ovite-jc t detection of part

Simple vision - detect edges« holes, corners, etc.

Complex vision - retognize shapes

\ . . .

-38-
Question lb)

This question attempted to quantify to some degree the cost

that a potential u&ct felt he or she could justify for a particular sensor capability.

SENSORS

lb) For the sensors from question la< enter the cost that

can be justified for the increased performance the sensor gives thr robot system.

1 Sensor Capability i from la i Cost Justified

per Robot

(dollars)

"louch *1700

(300-2500)

Simple Force

.

*3200

(2500-4000)

Complex Force *6200

(4500-6000)

Prox imity *2300

( 1000-3000)

Simpl(> Vision *10, 800

(10,000-15,000)

Complt»x Vision $23, 000

(20, 000-30, 000)

-39-
Question Ic ) This question addressed a different time frame than la). In

question la)> the participants uiere to prioritize sensory

capabilities in terms of immediate short-term economic benefit in their applications. Here« they are being asked to set

a priority for research on sensors. That is» on what sensor

systems should the research institutes expend their money

and resources to provide the highest long-term benefit? The

results are expressed in the same form as in question la).

Ic) Using the matrix belotu* rank the listed sensors in order of priority (1 through 6) for expenditure of

research and development money. Again* only fill in

the row(s) that corresponds to the area<s) you are familiar with. You may give two or more sensors the same

rank.

"1 ouch*

^

Simp 1

e

Fore e Comp lex

Fore e Proximity

Simp le

Vi si on Comp lexVision

Spot Welding 4. 0

(3-4)

3. 6

(2-4)

5. 0

(4-6)

2. 5

(2-3)

1. 7

(1-2)

5. 0

(5-6)

Arc Welding 5. 1 (4-6)4. 8

(4-6)

4. 9

(3-6)

3. 0

(2-4)

1. 1

( 1-1 )

3. 3

(2-5)

Drilling^ Routing

Grinding/ etc.

4. 6

(4-5)

2. 2

( 1-3)

2. 9

(2-3)

4. 6

(4-5)

1. 8

( 1-2)

3. 5

(2-4)

Small Part

Assemb 1

y

4. 5

(4-5)

2. 9

(2-4)

2. 9

(2-3)

3. 8

(3--5)

1. 4

( 1-2)

1. 8

( 1-2)

Machine Tool

Load ing/Unl oad ing

3. 9

(2-5)

3. 7

(3-5)

4. 4

(3-6)

3. 2

(2-4)

1. 7

( 1-3)

2. 9

(2-4)

Press

Load ing /Unl oad ing

3. 1 (2-4)

3. 5

(2-4)

4. 6

(4-5)

3. 3

(3-4)

2. 3

( 1-3)

3. 6

(2-6)

-40-
The follouing are the responses for questions 2 through 10.

SENSORS

2) For each of the sensors belou>> predict the year

(uhen robots uii)l be commercially available with that

capability and predict the percentage of robots shipped

in 1985 that will have that capability.

Year Commercially

Available at

the Price in lb)

/. of Robots

Shipped in 1985 with

' That Capability

Touc h

[

1980

< 1979-1980)

387.

( 107.-50O

Simple Force 1980

< 1980-1981

)

19"/.

( 107.-207.)

Complex Force 1983

( 1982-1984)

117.

(37.-107.)

Prox imi ty 1980

< 1979-1980)

227.

( 107.-207.)

Simple Vision I 1981

! (1980-1982)

I 187.

1 (107.-207.)

Complex Vi&ion 1 1984

! (1982-1985)

! 107.

! (17.-107.)

-41-
SENSORS

Enter the percentage of uiork in the application area(s)

you are familiar luith that is characterized bg the degree of part misalignment described in each column of

the matrix beloui. Within an application area (a rou in

the matrix)* the percentages should sum to lOO^C.

Ultra

Hrec ise

Prec ise Crude Surface Random

Spot Welding

___________ _

10

(0-15) (50-75)

P7

(10-30)

n (0-5)

\j (0-0)

J Arc Melding 1 12

! <0-15)

52

(35-65)

31

(20-35)

5

(0-10)

0

(0-0)

Drilling! Routing ! 28

Grinding, etc. ! (0-30)

46

(30-50)

22

( 10-30)

4

(0-5)

0

(0-0)

• Small Part ! 25

Assembly ! (10-35)

29

(25-40)

13

( 5-20

)

18

( 10-20)

15

( 5-20

)

1• Machin* Tool 1 li

Load ing /Unload irig ! (0-20)

32

(20-45)

25

(14-40)

12

(5-16)

20

(5-20)

Press I 14

Load ing /Unload iiig I (0-20)

25

(15-35)

20

(10-20)

18

( 10-20)

23

( 5-30

)

» Ultra Precise - lot^ite part uhere position known to < .050"

Precise - locate part where position known within . 050"< 1 degree

Crude - locate parts were position is known within 1"/ 20 degrees

Surface - locate parts on a known surface but within a random

orientation and position (e.g. part randomly oriented on a conveyor)

Random - locate pai-ts with large displacements in all three positional

coordinates and al) three rotational coordinates (e.g. bin picking)

-42-
SENSORS

4) What percentage oF the tasks in the application area<s)

you are familiar with require the robot to be able to

track a moving line? In what percentage of tasks would

it be useful fc«r the robot itself to be mounted on a moving platform?

1

< Percentage of I Applications i Requiring '

L ine roiiowing

Percentage of

Applications

In Which

txouOv riouixivy

Would be Useful

opoir weioing

(407.-507.)

cW /.

( 107.-207.)

Arc Welding 157.

(57.-207.)

237.

( 1 57.-257.

)

Drilling* flouting

Grinding! etc.

57.

(07.-107.)

, 257.

I ( 1 57.-307.

)

Small Part

Assemb 1

y

177.

I (107.-357.)

1 1 27.

! (57.-157.)

Machine Tool

Load ing/Unload ing

I 117.

I (57.-157.)

1 287.

! ( 207.-307.

)

Press

Load ing/Unload ing

1 57.

! ( 27.-67.

)

1 207.

I (107.-257.)

-43-
CONTROL

5) Estimate for each of the years given below the percentage of robots shipped in the U.S. market that will

have the control capabilities listed. Each column

should sum to 100%.

1980 1985 1990

Point-to-Point ! Adjustable Stops i 28

(19-38) , 18(13-18)

12

(8-16)

Servo Point-to -Point ! 44

(38-52)

33

(27-35)

27

(12-29)

Continuous Pf»th

12

( 10-14)

22

(13-27)

21

(16-29)

Coordinate Transformation

(straight line, joystick*

line following)

12

( 10-19)

21

(13-27)

I 27

I (16-29)

Trajectory Optimization

! 2

I (0-5)

1

1

! 6

1 (2-9)

1

1

! 13

1 (8-12)

1

1

-44-
CONTROL

6) For each of the years given belou estimate the percentage of robots shipped in the U.S. market that uill

utilize the teach/program method listed. Each column

should sum to 100*/.. — ————— 1

I 1980 !

1

1 1985 I 1990

Sequence/ Adjustable Stops

26 i (20-30)

19

( 1 5-20

)

12

(8-17)

Teach-Playbec k (rate control box)41

(35-50)

25

( 20-30

)

16

(8-21

)

Teach-Play bt<c k in

External Coordinates

(joystick/ xyz< etc. )

20

( 10-25)

22

( 19-25)

17

(8-21

)

Teac h -Play b tic k uith Editinct

11

(5-15)

20

( 1 5-30

)

25

( 17-29)

Off-Line Programming/

Higher Level Languctges

2

I (0-5)

11

(5-15)

2?

! (13-25)

Automatic Programming

Computer Generatff, Uobot

Program

! 0

I (0-0)

1 3

I (0-5)

1 8

! (3-13)

-45-
CONTROL

7) For the years Jit. ted belou)« estimate the percentage of

robots that uij ) 1 be incorporated into integrated

computer-aided ftu-oiuf ac tur ing systems.

1980 1985 1990

Percentage of Robots in 2. 1 9. 9 25

Integrated Sy t>tem». ( 1-5) (5-10) ( 1 5-30

)

-46-
CONTROL

8) For each of the performance characteristics described

in the columns beloui« enter a number from 1 to 5-«- to

indicate its importance to the application area(s) you

are familiar with. You may give more than one characteristic the same rank.

J

j j J j-,^

j Fast

Ohort

(loves

1

1 High

Slewing

Speeds

1 High

Positional

Accuracy

^o n c n T* Directed

Control

Fast

Programming

nffi—L i no Programming

Spot Welding 1. 0

( 1-1

)

2. 0

(2-2)

2. 3

( 1-3)

2. 9

(2-3)

3. 0

(3-3)

3. 7

(3-4)

Arc Melding 3. 9

. (3-5)

3. 2

(3-4)

1. 4

( 1-2)

1. 0

(1-1

)

2. 5 (2-3)3. 7

(3-4)

Drilling, Routing

Grinding, etc.

2. 7

( 1-4)

3. 4

(2-5)

1. 0

( 1-1

)

2. 6

( 1-3)

2. 0

(2-2)

2. 0

(2-2)

Small Part

Assembly

1. 7

(1-2)

2. 0

(2-2)

1. 0

( 1-1

)

1. 6

(1-2)

2. 7

(2-3)

3. 3

(2-4)

Machine Tool

Load ing/Unl cad ing

2. 2

(2-3)

1. 5

( 1-2)

2. 6

(2-3)

2. 8

(2-3)

3. 0

(3-3)

3. 9

(3-4)

Press

Load ing /Unload ing

2. 6

(2-3)

1. 4

( 1-2)

2. 6

( 1-3)

2. 9

(2-4)

3. 0

(3-3)

3. 9

(3-4)

» 1 - critical to tht- application

2 - highly advantageous for more effective and efficient use of robot

3 - offers some advantages but not absolutely necessary

4 - may need this capability sometime

5 — never need this capability

-47-
MARKET

9> Estimate the number of robots shipped by U.S. manufacturers and the dollar value of these shipments for each

of the years listed.

1980

~ —— —

1

1 1985 1990

Number of Robot Unitp 1170 I 4800 17100

Sh ipped (800-1500) 1 (3500-6000) ( 10. 000-20. 000)

Dollar Value of 60 1 225 780

Shipments (*M> (50-75) I (175-270) (450-1000)

This corresponds to approximately a 30% per year growth rate

both in dollar volume and in units shipped.

-48-
Rf-CiEARCH PROPERTIES

10) Give the percentape of research funds/effort which you

feel should be tsvgeted to each of the areas below.

Off-Line Hrosramming 1 12 (5-15)

Control S>i|i»iems 1 11 (9-15)

Mechanical Cjy&tems 7 (5-10)

End EFf et tors 10 (5-10)

Touch* Foi^ce> loique. Sensing 11 (9-14)

Binary Vision 14 (10-17)

Gray Sc£>lf Vision 12 (5-15)

Integration Into CAM Systems 8 (5-10)

Sa f fty 4 (2-5)

Mob i 1 i ty /Line tracking I 4 (0-5)

Simulation c;nd Modeling

_

! 6 (3-10)

therf. 1 1 (0-1)

! 100*/.

-49-
NBS-n4A iREv. 2-ec)

[ U.S. DEPT. OF COMM. 1, PUBLICATION OR 2. Performing Organ. Report No. 3. Publ ication Date BIBLIOGRAPHIC DATA

REPORT NO. SHEET (See instructions) NBS SP 602 April 1981

4. TITLE AND SUBTITLE

NBS/RIA Robotics Research Workshop

Proceedings of a Workshop Held at the National Bureau of Standards, Gaithersburg,

MD, November 13-15, 1979

^Editors:

James S. Albus,• G.J. VanderBrug, AnthonyJ J. Barbera,1 M.L. - - - — - Fitzgerald. - — - Thomas E. Wheat!

6. PERFORMING ORGANIZATION (\\ joint or other than NBS, see instructions) 7. Contract/Grant No, NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE 8. Type of Report & Period Coverec WASHINGTON, D.C. 20234 Final

9, SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

National Bureau of Standards and

The Robot Institute of America

20501 Ford Road, P.O. Box 930

Dearborn, MI 48128

10. SUPPLEMENTARY NOTES

Library of Congress Catalog Number: 80-600192

I I Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significont information. If document includes a si gnificant

bibliography or literature survey, mention it here)

The NBS/RIA Robotics Research Workshop had two objectives: 1) To provide a forum

for structured discussions between researchers in robotics and manufacturers and

users of robot systems and 2) To develop a consensus forecast of future developments

in sensors and control systems for industrial robots.

The 3-day workshop brought together 31 researchers, manufacturers, and users of

industrial robots in order to deteirmine the needs and priorities for future

research in sensors and control techniques for industrial robots. There were

no formal papers; instead, small group discussions and presentations and the

preparation of a Delphi Forecast were used to address research needs and priorities.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Delphi Forecast; robot control; robot vision; robotic assembly; robotic standards;

robotics research

13. AVAILABILITY

Pxl Unlimited

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