- Email: [email protected]
Hi-tech for home and office
355
Applications
Hi-Tech for Home and Office M u r r a y A. M u s p r a t t * Department of Civil Engineering, University of Illinois, 2143 Newmark Lab., 208 N. Romine Street, Urbana, 1L 61801, U.S.A. High technology is having an increasing impact on the day-today lives of all Americans. However the building industry has been somewhat reluctant to embrace the full range of HiTech possibilities available, both during the construction process and during the in-service operational stage. Possible HiTech ensembles for construction and operation of home and office buildings are described, with particular emphasis being placed on technology that is essentially commercial already.
Keywords: Construction industry, Home automation, Office automation, Robotics, Networking, Integrated automation system.
Murray A. Muspratt is presently on the faculty of Civil Engineering at Chisholm Institute of Technology, and has previously held visiting research positions at MIT, U C Berkeley, Princeton, Stanford, and McGill Universities, as well as at the University of Illinois at Urbana. He has published internationally on a wide range of topics, including mechanics, structure, transportation, management, systems, computers, hydrology, geomechanics, education, technology policy, as well as robotics. Mr. Muspratt holds a number of elected office positions in the Institution of Engineers, Australia. * Present address: Chisholm Institute of Technology, POB 197, Caulfield East, Victoria 3145, Australia. Elsevier Science Publishers B.V. Computers in Industry 12 (1989) 355-366 0166-3615/89/$3.50 © 1989 Elsevier Science Publishers B.V.
1. Introduction
A wide range of new technologies are being developed and commercialised at an increasing rate [5]. One of the great challenges of the age is to be aware of these developments, and to make judgements on how they might best be integrated into day-to-day engineering activities in the most cost-effective way. The home and the office are the centers of focus of a large percentage of the population, and the technology already commercially available for effecting the economies of automation in these spheres of human need is an issue that might be accorded close scrutiny by the engineering profession. American economy, which dominated the global economy after World War II, is now being subjected to increasingly fierce competition, especially by the Japanese. A key philosophy that the Japanese have used to great effect is that of integrated automation. In the industrial scene, Eli Whitney originally proposed interchangeable parts, Henry Ford the production line, and now the third evolutionary step, the Japanese step, is that of integrated automation. To some extent American manufacturing industries have already implemented the third step, but for civil engineering projects, the potential is still largely untapped. Productivity in civil engineering projects has been static for two decades now [4] and novel suggestions for improvement are urgently needed [3]. Basic integrated automation for civil projects would mean the integration of design, construction, and service/operation within a HiTech environment such as to maximise productivity. However contemporary design methods are already HiTech-intensive and sophisticated, and possibly comprise only 5% of project cost, so the large budgets allocated for construction in the short term, and for service costs during the design life of the building, might best be targeted for integrated automation.
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Applications
Computers in Industry
2. H o m e automation
2.1. During Construction The use of automation processes during the construction of homes was first suggested decades ago to capitalise on the productivty improvements achievable off-site in a factory environment [2]: Industrialised or modular building units were to be prefabricated in the factory, transported to the site and installed. However the logistics of transporting such units on public highways, together with the difficulty of handling and lifting heavy dead-weight units without special bracing, tended to defeat the original concept. Traditional on-site home construction has really changed little in a century, although heavy plant for site clearing, ready-mixed concrete delivered to the site, power tools for the workmen, sheet panels for partitions, etc. have provided productivity improvements in a fragmented way.
Integrated automation for construction on site may now be achievable with the present state of technology. The first stage of such automation could be as shown in Fig. 1_ with the robot manipulator, end effector and controller being the key technological elements. Robot manipulator ensembles are arranged on the leading and trailing gantry robots to ensure that work-space trajectories envelope the home under construction in an optimal way, while a production process using a further manipulator ensemble is installed in the trailer-bay of the truck to provide wall, floor, roof, and truss units for the home. A range of end effectors appropriate to the tasks performed by the robot ensembles is required, while control is achieved in an integrated way to ensure correct synchronisation. Partial reprogramming of robot controllers off-line ~ith the aid of simulation could improve the custom-built quality of successive homes constructed. The conceptual framework for home construction using
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Computers in Industry
357
M.A. Muspratt / HiTech for home and office
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Table 1 Transmission priorities Subsystem
Purpose of data
Delay (10- 3 s)
Priority
Smoke detector Crime alert Lighting Door sensor Telephone (analog, digital, cellular, telex, facsimile, video) Stove Refrigerator Airconditioner Laundry Television Microcomputer (banking, shopping, booking, data) Home robot Power
Fire Illegal entry Blown fuse, tube Visitor
1 2 3 4, 6
1 2 3 4
guaranteed guaranteed guaranteed statistical (50%)
Incoming signal Cooking complete Malfunction Over-heat, over-cool Washing complete Videorecording
5, 7 8, 10 9, 11 12, 15 13, 16 14, 17
4 5 5 6 6 6
statistical (50%) statistical (66%) statistical (33%) statistical (33%) statistical (33%) statistical (33%)
Information transfer Work status, malfunction Solar day-night input
18, 20 19, 21 22
7 statistical (50%) 7 statistical (50%) 8 guaranteed
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robots as shown in Fig. 1 is but one of many that might be proposed, and the volatility of developments in robotics is adding to the range of choice every day. However, the greatest challenge for the home construction industry seems to be to take the first step with a prototype concept, and then to progressively add improvements in the light of experience.
2.2. During Seroice / Operation Unlike office automation, home automation has yet to become widely perceived as a pressing need. but much of the technology that might be feasible for home application is already available commercially off-the-shelf. A possible schema for all-electric home automation is shown in Fig. 2, the power being supplied from the ulility grid as welt as from solar collectors. The central communication link is an Ethernet local area network (LAN) with a data rate of t0 megabits/sec to allow T V / C R T signals in one subsystem to share highresolution video frames with other video subsystems in real time. A limited capacity bus for such a home L A N might best use a Carrier Sense Multiple Access protocol with Collision Detection (CSMA-CD) to obviate the collision of signals eminating from different subsystems by assigning transmission priorities as given in Table 1. In C S M A - C D LAN's, back-off algorithms generate a prioritised queue of all subsystems contending for acquisition of the network, each subsystem node being allocated a back-off delay m milliseconds as indicated in Table 1. Urgent alarm subsystems are allocated the highest priority and the shortest delay, but these may be modified as necessary from the home-bus controller. Should multiple subsystems try to access an activated L A N simultaneously, they all back off and choose the delay allocated to them before trying a second access. Two or more subsystems with the same priority level choose randomly from their delay sets for their second attempt at access. The general configuration shown in Fig. 2 can be extended to include subsystems such as: earthquake alert; water-plumbing status, garden sprinklers; structural sensors for foundation settlement. snow load, and outdoors robot for garbage disposal, lawn mowing, snow removal, surveillance, etc.
Computers In lndust(v
The one critical resource is power, and a back-up generator may be desirable during a mains power failure. The telephonic technology in the home can be integrated through a private branch exchange (PBX) for normal switching. However a further level of service interworking can be established. and information can be stored and processed if an integrated service digital network (ISDN) (described in Section 3 for office automation) is used. The ISDN is itself connected to the main home bus controller, while its broadband capacity will not only ensure color video telephony, video storage and retrieval, but video conferencing from the home may be effected. HA technology may be modularised to accomodate particular needs, for example: integration with office, factory or site automation systems for working people in the home: - housekeeping operation for the housewife: - computer-aided instruction for school children: health care robot for the elderly and child-care robot: and telephonic signals sent by a household member to an intelligent home may be used to turn on lights, start cooking, record television programs. transmit telephone messages recorded in the home. provide financial information on home budgets, start snow removal on driveway by robot or subgrade heating; and provide such remote control directly to analog equipment, or through an analog-to-digital converter for digital equipment. The housewife, the children and the elderly may not have been trained to a high level of skill in technology, so the home technology that is used must be particularly user-friendly, rugged, and error-tolerant. Rapid development of large-scale integration (LSI) and tumbling hardware costs have rendered a wide range of commercial technology affordable for home use. In the future, a similar decline in the costs of photonic as well as electronic technology will potentially broaden the application domain still further.
3.
O f f i c e
A u t o m a t i o n
3.1. During Construction The automation of the construction processes for office buildings can capitatise on the repetition
Computers in Industry
M.A. Muspratt / HiTech for home and office
359
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Fig. 3. Office construction automation using robots.
of a multi-storey geometry to generate a productivity multiplier, but the inaccessibility and precariousness of high-rise construction, the heavy loads being handled, and the harsh environment conspire together to mandate a basic reconfiguration of robotic procedures used in the manufacturing industry, or even those proposed for home construction. Robot safety also becomes a major issue, and a robot running amuck and throwing itself off a ten-storey building or dropping steel girders through floors below can create havoc. In Fig. 3, some robot configurations for office construction automation are shown, and linked to a central host control-computer by token-passing
bus. The four configurations specifically identified as potentially useful for office construction are: (a) Bulldozer Robot. A semi-autonomous robot designed to operate in a master-slave synchronised squad, to have on-board topographic information and sudgrade levels in digital form, and to utilise sensors for ground speed, direction, power generated, etc. The master robot would be manned to inject human intelligence into the squad's response to unforeseen eventualities. (b) Multipurpose Constructor Robot. Designed to travel in horizontal or vertical planes, has telescopic axles to capture support from members in the structural frame, and has interchangeable end
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Applications
Computers in Indtmtry
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effectors to perform a wide range of construction tasks. This robot may also work in synchronised squads to generate a productivity multiplier. (c) Brickbot. Designed for dry-wall construction, it has four manipulators attached to a pantograph carrier that traverses a vertical reaction frame. The manipulators lay grout on top of the previous course, place a brick, inject further grout into a vertical gap between the new brick and the previous brick on the same course, and then clean excess grout from the course surface with a rotary brush. (d) Framebot. A robot designed for construction work within space frames of buildings, and with major orientations of manipulator trajectories conforming to horizontal or vertical work modes. The frmnebot may work in tandem for heavy lifting, have a wheelbase similar to the column spacing to minimise bending stresses in
support beams, and be electro-magnetically locked to the support beams for stability during work activities. The robots described above would need to be designed for payloads to be handled, end effectors to be used, the type of programming and control installed, speed and accuracy required, etc., but the further conceptualisation that such robotic suggestions might stimulate are invaluable for developing scenarios for robot-intensive construction in the future [1,7].
3.2. During Service/Operation Office automation has been a topical issue for a number of years now. and an increasing sophistication in office technoIogy is already apparent. The present challenges seem to be improved userfriendliness, the networking of different technologies from various vendors so as to capitalise on
Computers in Industry
particular capabilities, and to integrate office automation with site and factory automation in a comprehensive way. 3.2.1. User Friendliness User friendliness is being improved all the time, but this tends to be counterbalanced by simultaneous growth in sophistication. The expanding range of commercially available software and of compilers for high-level languages, translater algorithms for converting coding in one language to that in another, compatibility of standard software packages with an increasing range of hardware architecture, light pen, mouse or teach-pendant for input, smaller sizes and increased portability, declining cost rendering job-specific technology and multiple-locations of familiar technology viable, etc., all tend to provide the user with a legible technology environment. Comprehensive standardisation in an industry as volatile as HiTech automation is really impossible, but partial standardisation of mass-market items does promote transportability of skills and reduced learning curve. A more computer-literate workforce eminating from educational institutions also ensures that a more complex user-friendliness level might be acceptable than in former times. 3.2.2. Networking The homebus mentioned previously is a form of technology networking, but the networks used in office automation generally require a higher capacity and speed to be useful, as well as the integration of a wider range of more complex technical units. Figure 4 shown a possible configuration for office automation. The central spine is a 7-level, token-passing bus broadband coaxial cable called the officebus. Each ensemble of technology linked into the officebus has a gateway through a datasystems-token interface module, and the final interface of the latter to the officebus then requires a high-level data-link control. The 7 levels of the officebus defined as necessary by the International Standards Organisation in Geneva for open system integration are [6]: 7: application layer (programmable terminals; application software), 6: presentation layer (ASCII, binary), - 5 : session layer (interfaces layers), -4: transport layer (connection control),
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361
-3: network layer (data routing), -2: data-link layer (high-level data-link control; error checking) -1: physical layer (token-passing bus broadband coaxial cable; internodal data transfer) The networking system described above is designed to ensure compatible interface protocols between ensembles of technology from different vendors, and is a more flexible open-system integration than Ethernet or M A P (manufacturing automation protocol from General Motors). Instead of using the C S M A - C D of the Ethernet and priority access allocation to network nodes, the token-passing bus systematically passes the token to each network node in turn. The node with the token then has transmission-reception rights for a defined time period. The bus ensures that all network nodes share the same electrical pathway, and so processing requirements may be spread across the entire network, distributed databases and file sharing can be effected, while interface protocols for software running on machines from different vendors linked to different nodes may be defined. Programmable controllers have begun to replace hard-wired relay logic for every conceivable office function. A control computer is now needed to orchestrate and optimise the work of these controllers, a s u p e r c o m p u t e r with parallel processors is necessary where processor overload occurs in large offices, and a central database provides a knowledge center for storage and retrieval of information needed for business activities. The range of industrial and office electronic equipment commercially available grows year by year, and the major challenge is now often to know what is available, and how to make an optimal selection to satisfy needs. The systems shown in Figs. 4 and 5 are but one of m a n y possible configurations, and vendor advice may be sought. However, then a further decision must be made as to whether a single vendor or multiple vendors might best be involved. Some trade-off considerations are listed in Table 2. As office automation systems become increasingly complex, and as firms become increasingly reliant on the office automation system to conduct day-to-day activities, vulnerability to software or hardware downtime is increased. Some remedial approaches that might be considered include: "hot-standby" or redundant system, -
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Applications
Computersin Industry
Fig. 5. Telphonic integrated service digital network (ISDN) and cell of networked computers.
preventative maintenance based on record of possible problems, downtime penalty clauses in vendor contracts, software source code lodged in a trust in the event of vendor bankruptcy, insurance against business losses, and encryption of sensitive information such as that related to bidding or impending litigation. A disaster recovery plan should also be available for any contingency that might arise. The office automation system shown in Fig. 4 has two subsystems that have been specifically singled out in Fig. 5, namely, an integrated service digital network (ISDN) for telephonic technology, and a cell of networked computers dedicated to popular commercial software. The capability of
the two subsystems might be summarised as follows:
Telephonic Integrated Service Digital Network
-
- analog telephone - digital telephone - cellular telephone link to travelling automobiles facsimile machine telex machine video telephone - modem link to a personal computer -
-
Cell of Networked Computers - ICES for civil engineering design - C A D for computer aided drafting
M.A. Muspratt / HiTech for home and office
Computers in Industry Table 2 Vendor selection Single vendor
Multiple vendors
Standardisationreduces learning curve Direct upgrade path Good vendor support Networking is simple Economy of bulk purchase Best for small firm
Best technologycan be selected for each task Can shift upgrade paths in line with vendors' innovations Cross leverage on vendorprices Best for large firm
Disadvantages Limited selection of technology Upgrade path limited by vendor innovation Vendor acquires leverage over firm Vendor may go out of business and leave firm locked i n t o dated and degrading systems
Multiple learning curves Options for upgrade paths need reassessment Vendorsupport is variable Networkingis complex Duplicationof capabilitymay exist
Advantages
- CPM for critical path methods database management - wordprocessing spread sheets -
Such telephonic and computer networks generally use dedicated in-house circuits in large firms, but where a large communication need exists with external people such as clients, vendors, contractors, factory managers, etc., public communication systems may be used to supplement the capability. If a large volume of information must be transferred in real time from the office to a major site for a prolonged construction period, the microwave communication system shown in Fig. 4 may be cost-effective, especially should the site be inaccessible. A satellite link can also form part of the communication architecture for maintaining information flows with head office, and with remote sites in foreign countries. Mobile centers in need of real-time communication, such as plant operators on site, office workers or workmen with changing work stations, vehicular supplies travelling on public highways, emergency personnel required at a crisis center,
363
etc., can be reached by radiotelephonic links. The tendency today seems to be towards cableless systems, not only for information but for power as well. Such non-contact systems will be particularly appealing to the construction industry because the continually changing activities on site, and the continually changing site locations themselves in the longer term, demand the reconfiguration of the information and power networking topology on an on-going basis. Declining costs of technology will also render private networks rather than public networks more attractive, and such networks can carry multi-media signals, be value-added with storage and processing capability, and the degradation and error accumulation during peak-load periods for public common carriers can be avoided. Availability as required is also ensured. The integrity of signals in local-area networks can generally be maintained without relay or booster stations, but with wide-area networks, mobile relay stations may be strategically located as required. 3.2.3. Integrated Automation Office automation might be addressed at three levels of integration: (i) design, construction and operation of a building; (ii) integration of office, factory and site automation; and (iii) integrated automation system. (i) Design, Construction and Operation of a Building (CADD/CACM/OA). The issue of design and construction integration has been addressed to some extent recently, but the arrival of the intelligent office building demands a more rigorous evaluation of in-service operational requirements and how these affect the design and construction decisions. The purpose for which a building is to be used, dead and live loads on floors, clear-span between columns and ceiling height, conduits for power, lighting, plumbing, heating, ventilation and airconditioning (HVAC), etc., are traditionally given consideration during design-construction decision making, but the advent of home and office automation philosophies seem to demand a systematic evaluation of electronic technology to be used in the building. Token-passing buses, satellite dishes, private branch telephonic exchanges, built-in computer hardware, robot accessibility, etc., are becoming increasingly common in
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Computers in Industry
Table 3 CADD/CACM/OA CADD
CACM
OA
Micro-mini-mainframe Graphics terminals Printers, plotters Databases: specifications, OA needs design algorithms design standards geometry library attribute library constructability
Management information system Paperless project Portable transceivers for men Bar-coded materials Numerical-control plant Robots: mobility manipulators end effectors
Hardware. software Networks: bus. ethernet local-area, wide-area land-lines, microwave. satellite baseband, broadband encryption error control Hardwired systems
sensors
controls
buildings, and may become standard installations in buildings of the future as was running water a century ago. The technologies already available for building automation are wide-ranging, and a shake-out period of competing and apparently equally plausible and cost-effective options seems inevitable before standards might be set. This period of uncertainty wilt be further compounded by the explosive growth of new technologies a n d the rapid obsolescence of contemporary technologies. So a very flexible upgrade path must be built into building automation configurations. Personal needs and preferences and fads will also intervene to add further variables to the decision making process. However using the present status of knowledge, a summary of an integrated system for computer-aided design and drafting (CADD), computer-aided construction management
(CACM), and office automation (OA) is given in Table 3.
(ii) Integration of Office, Factory and Site A utomation (OFSA). The integration of office automation systems in the headquarters of an engineering firm with factory automation that services the needs of a construction site that is also automated, is a global approach to the delivery process for a constructton project. A basic framework for OFSA is shown in Fig. 4, although is is only the office-automation subsystem that has been elaborated on: further details on possible office, factory, and site automation are given in Table 4. (iii) Integrated Automation System (1AS). An integrated automation system (IAS) for the building industry might be defined as integration of computer-aided design and drafting (CADD),
Table 4 Office, factory and site automation (OFSA) Site automation
Office automation
Factory automation
Technology
Plant. equipment Robot programming and use Computer-aided management Communications
Control computer Supercomputer Central database Engineering work stations Cell of networked computers Telephonic network Satellite. microwave links
Robots Numerical control machines Conveyors Automatic storage-retrieval Quality inspection Inventory control
Tasks
Men, materials, plant, robots Time, cost, quality, bids Subcontractors. vendors, union Construction, commissioning Methods improvement, safety
Planning, project portfolio Client relations, contractors Feasibility Finance, insurance Design. research
Procurement Fabrication Precasting Delivery to site Testing laboratory
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c o m p u t e r aided c o n s t r u c t i o n m a n a g e m e n t (CACM), and office automation (OA), with office, factory and site automation (OFSA). That is, IAS = C A D D / C A C M / O A + OFSA. Such a level of integration is theoretically possible at the moment, and some integration has already been achieved in the manufacturing industry for automobiles; but for the construction industry, built-in inertias such as the following have generated resistance to change: - freedom from foreign competition; - entrenched labor practices, conservative mindset; unstructured and non-repetitive site activities render integration difficult; - change in topology of technology for change of site or project type; site automation must be hardened for harsh environment; - robots are possibly the key site technology, and have not been fully developed for construction work; and - site inaccessibility often adds further difficulties.
(iv) Other topologies The range of topologies for integrated automation used on civil projects is as broad as one's imagination, but some issues that might well be singled out for particular attention in the future include: - A C L - - a construction language: an all-purpose, high-level, software language used for design, construction management, and robot controllers. - C A C P - - c o m p u t e r - a i d e d construction planning: artificial intelligence applied to the responsibilities of the project manager. C A T - - c o m p u t e r - a i d e d testing: quality control and testing of soils, concrete, asphalt, steel, etc. CIC--computer-integrated construction: global philosophy for construction organisation through all phases, and using computers extensively. This is a special case of IAS, and would achieve the paperless project by automatic, realtime, data transfer. - C A P - - c o n s t r u c t i o n automation protocol: used in broadband, token-passing bus that links modules of construction technology. - FCS--flexible construction system: a system with the ability to construct a variety of differ-
M.A. Muspratt / HiTeeh for home and office
-
-
-
-
4.
365
ent projects with minimal setup or reprogramming time. ICC--integrated C A D D and CACM: integration of computer-aided design and drafting with computer-aided construction management. IESCE--integrated expert systems for civil engineering: expert systems developed by various authors are integrated into a total system. P M I S - - p r o j e c t management information system: similar to CACP, but lower level of artificial intelligence. N C P - - n u m e r i c a i l y controlled plant: applies to construction plant and equipment that are fitted with computer controllers, and so may be programmed with instructions. T A - - t u r n k e y automation: an automatic system supplied with hardware and software, and ready for use on a proposed task.
Conclusions
About $300-billion is spent annually on construction projects, and over half of this is budgeted for home and office buildings. However productivity levels in building construction have been static for two decades now, so even a modest improvement would realise large savings in real terms. Time is now right for a major reassessment of the methods used to construct and operate buildings, and how integrated automation might be structured through design, construction, and service operations stages to maximise value for money.
Acknowledgement
The author is indebted to Professor L. Boyer and Professor W. Hall for the opportunity to pursue this research at the University of Illinois.
References
[1] C.W. Ibbs, " F u t u r e directions of computerised construction research", Construction Eng. Manage ASCE, Vol. 112, No. 3, 1985, pp. 326-345. [2] M.A. Muspratt, " U r b a n degradation and building systems". J. Urban Planning, ASCE, Vol. 99, No. 2, 1973, pp. 235-246. [3] M.A. Muspratt, "Research and education for the construc-
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tion industry", J. Professional Issues Eng., ASCE, Vol. 110, No. 1, 1984, pp. 7-18. [4] M.A. Muspratt, "Civil Engineering in crisis", J. Professional lssues Eng., ASCE, Vol. 112, No. 1, 1986, pp. 34-48. [51 M.A. Muspratt, "Artificial intelligence", J. Professional Issues Eng., ASCE, Vol. 112, No. 3, 1986, pp. 158-169.
Computers in Industry [6] S. Shera, , A new international structure for information systems standards", Computer, IEEE, Vol. 19, NO. 1, I986, pp. 102-103. [7] A. Warszawski, "Robots in the construction industry", Robotica, Vol. 4, 1986, pp. 181-188~
Applications
Hi-Tech for Home and Office M u r r a y A. M u s p r a t t * Department of Civil Engineering, University of Illinois, 2143 Newmark Lab., 208 N. Romine Street, Urbana, 1L 61801, U.S.A. High technology is having an increasing impact on the day-today lives of all Americans. However the building industry has been somewhat reluctant to embrace the full range of HiTech possibilities available, both during the construction process and during the in-service operational stage. Possible HiTech ensembles for construction and operation of home and office buildings are described, with particular emphasis being placed on technology that is essentially commercial already.
Keywords: Construction industry, Home automation, Office automation, Robotics, Networking, Integrated automation system.
Murray A. Muspratt is presently on the faculty of Civil Engineering at Chisholm Institute of Technology, and has previously held visiting research positions at MIT, U C Berkeley, Princeton, Stanford, and McGill Universities, as well as at the University of Illinois at Urbana. He has published internationally on a wide range of topics, including mechanics, structure, transportation, management, systems, computers, hydrology, geomechanics, education, technology policy, as well as robotics. Mr. Muspratt holds a number of elected office positions in the Institution of Engineers, Australia. * Present address: Chisholm Institute of Technology, POB 197, Caulfield East, Victoria 3145, Australia. Elsevier Science Publishers B.V. Computers in Industry 12 (1989) 355-366 0166-3615/89/$3.50 © 1989 Elsevier Science Publishers B.V.
1. Introduction
A wide range of new technologies are being developed and commercialised at an increasing rate [5]. One of the great challenges of the age is to be aware of these developments, and to make judgements on how they might best be integrated into day-to-day engineering activities in the most cost-effective way. The home and the office are the centers of focus of a large percentage of the population, and the technology already commercially available for effecting the economies of automation in these spheres of human need is an issue that might be accorded close scrutiny by the engineering profession. American economy, which dominated the global economy after World War II, is now being subjected to increasingly fierce competition, especially by the Japanese. A key philosophy that the Japanese have used to great effect is that of integrated automation. In the industrial scene, Eli Whitney originally proposed interchangeable parts, Henry Ford the production line, and now the third evolutionary step, the Japanese step, is that of integrated automation. To some extent American manufacturing industries have already implemented the third step, but for civil engineering projects, the potential is still largely untapped. Productivity in civil engineering projects has been static for two decades now [4] and novel suggestions for improvement are urgently needed [3]. Basic integrated automation for civil projects would mean the integration of design, construction, and service/operation within a HiTech environment such as to maximise productivity. However contemporary design methods are already HiTech-intensive and sophisticated, and possibly comprise only 5% of project cost, so the large budgets allocated for construction in the short term, and for service costs during the design life of the building, might best be targeted for integrated automation.
356
Applications
Computers in Industry
2. H o m e automation
2.1. During Construction The use of automation processes during the construction of homes was first suggested decades ago to capitalise on the productivty improvements achievable off-site in a factory environment [2]: Industrialised or modular building units were to be prefabricated in the factory, transported to the site and installed. However the logistics of transporting such units on public highways, together with the difficulty of handling and lifting heavy dead-weight units without special bracing, tended to defeat the original concept. Traditional on-site home construction has really changed little in a century, although heavy plant for site clearing, ready-mixed concrete delivered to the site, power tools for the workmen, sheet panels for partitions, etc. have provided productivity improvements in a fragmented way.
Integrated automation for construction on site may now be achievable with the present state of technology. The first stage of such automation could be as shown in Fig. 1_ with the robot manipulator, end effector and controller being the key technological elements. Robot manipulator ensembles are arranged on the leading and trailing gantry robots to ensure that work-space trajectories envelope the home under construction in an optimal way, while a production process using a further manipulator ensemble is installed in the trailer-bay of the truck to provide wall, floor, roof, and truss units for the home. A range of end effectors appropriate to the tasks performed by the robot ensembles is required, while control is achieved in an integrated way to ensure correct synchronisation. Partial reprogramming of robot controllers off-line ~ith the aid of simulation could improve the custom-built quality of successive homes constructed. The conceptual framework for home construction using
HDLC high-level data link control
P~,NT~a
MOOE~
FLO PY ~ SK
~
//
v,-
f
I
datasystems =~token-interface module
.~//~
"'~" IZ
HOMEBOT i
.
J Fig. 1. Home construction automation using robots.
Computers in Industry
357
M.A. Muspratt / HiTech for home and office
= coSma~lIc~eon
cellular phone
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Table 1 Transmission priorities Subsystem
Purpose of data
Delay (10- 3 s)
Priority
Smoke detector Crime alert Lighting Door sensor Telephone (analog, digital, cellular, telex, facsimile, video) Stove Refrigerator Airconditioner Laundry Television Microcomputer (banking, shopping, booking, data) Home robot Power
Fire Illegal entry Blown fuse, tube Visitor
1 2 3 4, 6
1 2 3 4
guaranteed guaranteed guaranteed statistical (50%)
Incoming signal Cooking complete Malfunction Over-heat, over-cool Washing complete Videorecording
5, 7 8, 10 9, 11 12, 15 13, 16 14, 17
4 5 5 6 6 6
statistical (50%) statistical (66%) statistical (33%) statistical (33%) statistical (33%) statistical (33%)
Information transfer Work status, malfunction Solar day-night input
18, 20 19, 21 22
7 statistical (50%) 7 statistical (50%) 8 guaranteed
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Applications
robots as shown in Fig. 1 is but one of many that might be proposed, and the volatility of developments in robotics is adding to the range of choice every day. However, the greatest challenge for the home construction industry seems to be to take the first step with a prototype concept, and then to progressively add improvements in the light of experience.
2.2. During Seroice / Operation Unlike office automation, home automation has yet to become widely perceived as a pressing need. but much of the technology that might be feasible for home application is already available commercially off-the-shelf. A possible schema for all-electric home automation is shown in Fig. 2, the power being supplied from the ulility grid as welt as from solar collectors. The central communication link is an Ethernet local area network (LAN) with a data rate of t0 megabits/sec to allow T V / C R T signals in one subsystem to share highresolution video frames with other video subsystems in real time. A limited capacity bus for such a home L A N might best use a Carrier Sense Multiple Access protocol with Collision Detection (CSMA-CD) to obviate the collision of signals eminating from different subsystems by assigning transmission priorities as given in Table 1. In C S M A - C D LAN's, back-off algorithms generate a prioritised queue of all subsystems contending for acquisition of the network, each subsystem node being allocated a back-off delay m milliseconds as indicated in Table 1. Urgent alarm subsystems are allocated the highest priority and the shortest delay, but these may be modified as necessary from the home-bus controller. Should multiple subsystems try to access an activated L A N simultaneously, they all back off and choose the delay allocated to them before trying a second access. Two or more subsystems with the same priority level choose randomly from their delay sets for their second attempt at access. The general configuration shown in Fig. 2 can be extended to include subsystems such as: earthquake alert; water-plumbing status, garden sprinklers; structural sensors for foundation settlement. snow load, and outdoors robot for garbage disposal, lawn mowing, snow removal, surveillance, etc.
Computers In lndust(v
The one critical resource is power, and a back-up generator may be desirable during a mains power failure. The telephonic technology in the home can be integrated through a private branch exchange (PBX) for normal switching. However a further level of service interworking can be established. and information can be stored and processed if an integrated service digital network (ISDN) (described in Section 3 for office automation) is used. The ISDN is itself connected to the main home bus controller, while its broadband capacity will not only ensure color video telephony, video storage and retrieval, but video conferencing from the home may be effected. HA technology may be modularised to accomodate particular needs, for example: integration with office, factory or site automation systems for working people in the home: - housekeeping operation for the housewife: - computer-aided instruction for school children: health care robot for the elderly and child-care robot: and telephonic signals sent by a household member to an intelligent home may be used to turn on lights, start cooking, record television programs. transmit telephone messages recorded in the home. provide financial information on home budgets, start snow removal on driveway by robot or subgrade heating; and provide such remote control directly to analog equipment, or through an analog-to-digital converter for digital equipment. The housewife, the children and the elderly may not have been trained to a high level of skill in technology, so the home technology that is used must be particularly user-friendly, rugged, and error-tolerant. Rapid development of large-scale integration (LSI) and tumbling hardware costs have rendered a wide range of commercial technology affordable for home use. In the future, a similar decline in the costs of photonic as well as electronic technology will potentially broaden the application domain still further.
3.
O f f i c e
A u t o m a t i o n
3.1. During Construction The automation of the construction processes for office buildings can capitatise on the repetition
Computers in Industry
M.A. Muspratt / HiTech for home and office
359
I\
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control computer
MULTIPURPOSE CONSTRUCTORROBOT
BULLDOZER ROBOT
i
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BRICKBOT
FRAMEBOT
Fig. 3. Office construction automation using robots.
of a multi-storey geometry to generate a productivity multiplier, but the inaccessibility and precariousness of high-rise construction, the heavy loads being handled, and the harsh environment conspire together to mandate a basic reconfiguration of robotic procedures used in the manufacturing industry, or even those proposed for home construction. Robot safety also becomes a major issue, and a robot running amuck and throwing itself off a ten-storey building or dropping steel girders through floors below can create havoc. In Fig. 3, some robot configurations for office construction automation are shown, and linked to a central host control-computer by token-passing
bus. The four configurations specifically identified as potentially useful for office construction are: (a) Bulldozer Robot. A semi-autonomous robot designed to operate in a master-slave synchronised squad, to have on-board topographic information and sudgrade levels in digital form, and to utilise sensors for ground speed, direction, power generated, etc. The master robot would be manned to inject human intelligence into the squad's response to unforeseen eventualities. (b) Multipurpose Constructor Robot. Designed to travel in horizontal or vertical planes, has telescopic axles to capture support from members in the structural frame, and has interchangeable end
360
Applications
Computers in Indtmtry
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effectors to perform a wide range of construction tasks. This robot may also work in synchronised squads to generate a productivity multiplier. (c) Brickbot. Designed for dry-wall construction, it has four manipulators attached to a pantograph carrier that traverses a vertical reaction frame. The manipulators lay grout on top of the previous course, place a brick, inject further grout into a vertical gap between the new brick and the previous brick on the same course, and then clean excess grout from the course surface with a rotary brush. (d) Framebot. A robot designed for construction work within space frames of buildings, and with major orientations of manipulator trajectories conforming to horizontal or vertical work modes. The frmnebot may work in tandem for heavy lifting, have a wheelbase similar to the column spacing to minimise bending stresses in
support beams, and be electro-magnetically locked to the support beams for stability during work activities. The robots described above would need to be designed for payloads to be handled, end effectors to be used, the type of programming and control installed, speed and accuracy required, etc., but the further conceptualisation that such robotic suggestions might stimulate are invaluable for developing scenarios for robot-intensive construction in the future [1,7].
3.2. During Service/Operation Office automation has been a topical issue for a number of years now. and an increasing sophistication in office technoIogy is already apparent. The present challenges seem to be improved userfriendliness, the networking of different technologies from various vendors so as to capitalise on
Computers in Industry
particular capabilities, and to integrate office automation with site and factory automation in a comprehensive way. 3.2.1. User Friendliness User friendliness is being improved all the time, but this tends to be counterbalanced by simultaneous growth in sophistication. The expanding range of commercially available software and of compilers for high-level languages, translater algorithms for converting coding in one language to that in another, compatibility of standard software packages with an increasing range of hardware architecture, light pen, mouse or teach-pendant for input, smaller sizes and increased portability, declining cost rendering job-specific technology and multiple-locations of familiar technology viable, etc., all tend to provide the user with a legible technology environment. Comprehensive standardisation in an industry as volatile as HiTech automation is really impossible, but partial standardisation of mass-market items does promote transportability of skills and reduced learning curve. A more computer-literate workforce eminating from educational institutions also ensures that a more complex user-friendliness level might be acceptable than in former times. 3.2.2. Networking The homebus mentioned previously is a form of technology networking, but the networks used in office automation generally require a higher capacity and speed to be useful, as well as the integration of a wider range of more complex technical units. Figure 4 shown a possible configuration for office automation. The central spine is a 7-level, token-passing bus broadband coaxial cable called the officebus. Each ensemble of technology linked into the officebus has a gateway through a datasystems-token interface module, and the final interface of the latter to the officebus then requires a high-level data-link control. The 7 levels of the officebus defined as necessary by the International Standards Organisation in Geneva for open system integration are [6]: 7: application layer (programmable terminals; application software), 6: presentation layer (ASCII, binary), - 5 : session layer (interfaces layers), -4: transport layer (connection control),
M.A. Muspratt / HiTeeh for home and office
361
-3: network layer (data routing), -2: data-link layer (high-level data-link control; error checking) -1: physical layer (token-passing bus broadband coaxial cable; internodal data transfer) The networking system described above is designed to ensure compatible interface protocols between ensembles of technology from different vendors, and is a more flexible open-system integration than Ethernet or M A P (manufacturing automation protocol from General Motors). Instead of using the C S M A - C D of the Ethernet and priority access allocation to network nodes, the token-passing bus systematically passes the token to each network node in turn. The node with the token then has transmission-reception rights for a defined time period. The bus ensures that all network nodes share the same electrical pathway, and so processing requirements may be spread across the entire network, distributed databases and file sharing can be effected, while interface protocols for software running on machines from different vendors linked to different nodes may be defined. Programmable controllers have begun to replace hard-wired relay logic for every conceivable office function. A control computer is now needed to orchestrate and optimise the work of these controllers, a s u p e r c o m p u t e r with parallel processors is necessary where processor overload occurs in large offices, and a central database provides a knowledge center for storage and retrieval of information needed for business activities. The range of industrial and office electronic equipment commercially available grows year by year, and the major challenge is now often to know what is available, and how to make an optimal selection to satisfy needs. The systems shown in Figs. 4 and 5 are but one of m a n y possible configurations, and vendor advice may be sought. However, then a further decision must be made as to whether a single vendor or multiple vendors might best be involved. Some trade-off considerations are listed in Table 2. As office automation systems become increasingly complex, and as firms become increasingly reliant on the office automation system to conduct day-to-day activities, vulnerability to software or hardware downtime is increased. Some remedial approaches that might be considered include: "hot-standby" or redundant system, -
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Applications
Computersin Industry
Fig. 5. Telphonic integrated service digital network (ISDN) and cell of networked computers.
preventative maintenance based on record of possible problems, downtime penalty clauses in vendor contracts, software source code lodged in a trust in the event of vendor bankruptcy, insurance against business losses, and encryption of sensitive information such as that related to bidding or impending litigation. A disaster recovery plan should also be available for any contingency that might arise. The office automation system shown in Fig. 4 has two subsystems that have been specifically singled out in Fig. 5, namely, an integrated service digital network (ISDN) for telephonic technology, and a cell of networked computers dedicated to popular commercial software. The capability of
the two subsystems might be summarised as follows:
Telephonic Integrated Service Digital Network
-
- analog telephone - digital telephone - cellular telephone link to travelling automobiles facsimile machine telex machine video telephone - modem link to a personal computer -
-
Cell of Networked Computers - ICES for civil engineering design - C A D for computer aided drafting
M.A. Muspratt / HiTech for home and office
Computers in Industry Table 2 Vendor selection Single vendor
Multiple vendors
Standardisationreduces learning curve Direct upgrade path Good vendor support Networking is simple Economy of bulk purchase Best for small firm
Best technologycan be selected for each task Can shift upgrade paths in line with vendors' innovations Cross leverage on vendorprices Best for large firm
Disadvantages Limited selection of technology Upgrade path limited by vendor innovation Vendor acquires leverage over firm Vendor may go out of business and leave firm locked i n t o dated and degrading systems
Multiple learning curves Options for upgrade paths need reassessment Vendorsupport is variable Networkingis complex Duplicationof capabilitymay exist
Advantages
- CPM for critical path methods database management - wordprocessing spread sheets -
Such telephonic and computer networks generally use dedicated in-house circuits in large firms, but where a large communication need exists with external people such as clients, vendors, contractors, factory managers, etc., public communication systems may be used to supplement the capability. If a large volume of information must be transferred in real time from the office to a major site for a prolonged construction period, the microwave communication system shown in Fig. 4 may be cost-effective, especially should the site be inaccessible. A satellite link can also form part of the communication architecture for maintaining information flows with head office, and with remote sites in foreign countries. Mobile centers in need of real-time communication, such as plant operators on site, office workers or workmen with changing work stations, vehicular supplies travelling on public highways, emergency personnel required at a crisis center,
363
etc., can be reached by radiotelephonic links. The tendency today seems to be towards cableless systems, not only for information but for power as well. Such non-contact systems will be particularly appealing to the construction industry because the continually changing activities on site, and the continually changing site locations themselves in the longer term, demand the reconfiguration of the information and power networking topology on an on-going basis. Declining costs of technology will also render private networks rather than public networks more attractive, and such networks can carry multi-media signals, be value-added with storage and processing capability, and the degradation and error accumulation during peak-load periods for public common carriers can be avoided. Availability as required is also ensured. The integrity of signals in local-area networks can generally be maintained without relay or booster stations, but with wide-area networks, mobile relay stations may be strategically located as required. 3.2.3. Integrated Automation Office automation might be addressed at three levels of integration: (i) design, construction and operation of a building; (ii) integration of office, factory and site automation; and (iii) integrated automation system. (i) Design, Construction and Operation of a Building (CADD/CACM/OA). The issue of design and construction integration has been addressed to some extent recently, but the arrival of the intelligent office building demands a more rigorous evaluation of in-service operational requirements and how these affect the design and construction decisions. The purpose for which a building is to be used, dead and live loads on floors, clear-span between columns and ceiling height, conduits for power, lighting, plumbing, heating, ventilation and airconditioning (HVAC), etc., are traditionally given consideration during design-construction decision making, but the advent of home and office automation philosophies seem to demand a systematic evaluation of electronic technology to be used in the building. Token-passing buses, satellite dishes, private branch telephonic exchanges, built-in computer hardware, robot accessibility, etc., are becoming increasingly common in
364
Applications
Computers in Industry
Table 3 CADD/CACM/OA CADD
CACM
OA
Micro-mini-mainframe Graphics terminals Printers, plotters Databases: specifications, OA needs design algorithms design standards geometry library attribute library constructability
Management information system Paperless project Portable transceivers for men Bar-coded materials Numerical-control plant Robots: mobility manipulators end effectors
Hardware. software Networks: bus. ethernet local-area, wide-area land-lines, microwave. satellite baseband, broadband encryption error control Hardwired systems
sensors
controls
buildings, and may become standard installations in buildings of the future as was running water a century ago. The technologies already available for building automation are wide-ranging, and a shake-out period of competing and apparently equally plausible and cost-effective options seems inevitable before standards might be set. This period of uncertainty wilt be further compounded by the explosive growth of new technologies a n d the rapid obsolescence of contemporary technologies. So a very flexible upgrade path must be built into building automation configurations. Personal needs and preferences and fads will also intervene to add further variables to the decision making process. However using the present status of knowledge, a summary of an integrated system for computer-aided design and drafting (CADD), computer-aided construction management
(CACM), and office automation (OA) is given in Table 3.
(ii) Integration of Office, Factory and Site A utomation (OFSA). The integration of office automation systems in the headquarters of an engineering firm with factory automation that services the needs of a construction site that is also automated, is a global approach to the delivery process for a constructton project. A basic framework for OFSA is shown in Fig. 4, although is is only the office-automation subsystem that has been elaborated on: further details on possible office, factory, and site automation are given in Table 4. (iii) Integrated Automation System (1AS). An integrated automation system (IAS) for the building industry might be defined as integration of computer-aided design and drafting (CADD),
Table 4 Office, factory and site automation (OFSA) Site automation
Office automation
Factory automation
Technology
Plant. equipment Robot programming and use Computer-aided management Communications
Control computer Supercomputer Central database Engineering work stations Cell of networked computers Telephonic network Satellite. microwave links
Robots Numerical control machines Conveyors Automatic storage-retrieval Quality inspection Inventory control
Tasks
Men, materials, plant, robots Time, cost, quality, bids Subcontractors. vendors, union Construction, commissioning Methods improvement, safety
Planning, project portfolio Client relations, contractors Feasibility Finance, insurance Design. research
Procurement Fabrication Precasting Delivery to site Testing laboratory
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c o m p u t e r aided c o n s t r u c t i o n m a n a g e m e n t (CACM), and office automation (OA), with office, factory and site automation (OFSA). That is, IAS = C A D D / C A C M / O A + OFSA. Such a level of integration is theoretically possible at the moment, and some integration has already been achieved in the manufacturing industry for automobiles; but for the construction industry, built-in inertias such as the following have generated resistance to change: - freedom from foreign competition; - entrenched labor practices, conservative mindset; unstructured and non-repetitive site activities render integration difficult; - change in topology of technology for change of site or project type; site automation must be hardened for harsh environment; - robots are possibly the key site technology, and have not been fully developed for construction work; and - site inaccessibility often adds further difficulties.
(iv) Other topologies The range of topologies for integrated automation used on civil projects is as broad as one's imagination, but some issues that might well be singled out for particular attention in the future include: - A C L - - a construction language: an all-purpose, high-level, software language used for design, construction management, and robot controllers. - C A C P - - c o m p u t e r - a i d e d construction planning: artificial intelligence applied to the responsibilities of the project manager. C A T - - c o m p u t e r - a i d e d testing: quality control and testing of soils, concrete, asphalt, steel, etc. CIC--computer-integrated construction: global philosophy for construction organisation through all phases, and using computers extensively. This is a special case of IAS, and would achieve the paperless project by automatic, realtime, data transfer. - C A P - - c o n s t r u c t i o n automation protocol: used in broadband, token-passing bus that links modules of construction technology. - FCS--flexible construction system: a system with the ability to construct a variety of differ-
M.A. Muspratt / HiTeeh for home and office
-
-
-
-
4.
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ent projects with minimal setup or reprogramming time. ICC--integrated C A D D and CACM: integration of computer-aided design and drafting with computer-aided construction management. IESCE--integrated expert systems for civil engineering: expert systems developed by various authors are integrated into a total system. P M I S - - p r o j e c t management information system: similar to CACP, but lower level of artificial intelligence. N C P - - n u m e r i c a i l y controlled plant: applies to construction plant and equipment that are fitted with computer controllers, and so may be programmed with instructions. T A - - t u r n k e y automation: an automatic system supplied with hardware and software, and ready for use on a proposed task.
Conclusions
About $300-billion is spent annually on construction projects, and over half of this is budgeted for home and office buildings. However productivity levels in building construction have been static for two decades now, so even a modest improvement would realise large savings in real terms. Time is now right for a major reassessment of the methods used to construct and operate buildings, and how integrated automation might be structured through design, construction, and service operations stages to maximise value for money.
Acknowledgement
The author is indebted to Professor L. Boyer and Professor W. Hall for the opportunity to pursue this research at the University of Illinois.
References
[1] C.W. Ibbs, " F u t u r e directions of computerised construction research", Construction Eng. Manage ASCE, Vol. 112, No. 3, 1985, pp. 326-345. [2] M.A. Muspratt, " U r b a n degradation and building systems". J. Urban Planning, ASCE, Vol. 99, No. 2, 1973, pp. 235-246. [3] M.A. Muspratt, "Research and education for the construc-
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Applications
tion industry", J. Professional Issues Eng., ASCE, Vol. 110, No. 1, 1984, pp. 7-18. [4] M.A. Muspratt, "Civil Engineering in crisis", J. Professional lssues Eng., ASCE, Vol. 112, No. 1, 1986, pp. 34-48. [51 M.A. Muspratt, "Artificial intelligence", J. Professional Issues Eng., ASCE, Vol. 112, No. 3, 1986, pp. 158-169.
Computers in Industry [6] S. Shera, , A new international structure for information systems standards", Computer, IEEE, Vol. 19, NO. 1, I986, pp. 102-103. [7] A. Warszawski, "Robots in the construction industry", Robotica, Vol. 4, 1986, pp. 181-188~