Automation and Robotics in Construction Industry
Short Description
Automation and Robotics in Construction Industry-An Overview...
Description
DEPARTMENT OF CIVIL ENGINEERING GOKARAJU RANGARAJU INSTITUTE OF ENGINEERING & TECHNOLOGY NIZAMPET ROAD, HYDERABAD-500090 APRIL 2012
CERTIFICATE This is to certify that project entitled “APPLICATION OF ROBOTICS IN CONSTRUCTION INDUSTRY” that is being submitted by M.PrithviRaj (08241A0130), K.CharanRaj (08241A0112), B.Navaneeth (08241A0125), A.Sai Krishna(08241A0137) in partial fulfillment of the requirement for the award of Degree of Bachelor of Technology in Civi Engineering, GOKARAJU RANGARAJU INSTITUTE of Engineering and Technology (Affiliated to Jawaharlal Nehru Technological University, Hyderabad) Is a record of bonafide work carried out by them under my guidance and supervision. The results embodied in this thesis have not been submitted to any other University or Institute for the award of any degree.
Mr. Dr.G.Venkata Ramana, Mr. V.Gajendra, Head of Department, Associate Professor, Civil Dept., Griet, Civil Dept.,Griet, Hyderabad. Hyderabad.
Dr. J.N.Murthy
ACKNOWLEDGEMENT
Success is epitome of hard work, cogency for fulfilling the mission, indefatigable perseverance and most of all encouraging guidance and steering. We express our sincere thanks to, Dr.Jandhyala Murthy Principal, GRIET for the support and motivation provided to us. It gives us an immense pleasure to express our gratitude to Prof. Dr.G.Venkata Ramana , Head of Department of Civil Engineering and Associate Prof. V.Gajendra, for their esteemed guidance and able supervision during the course of the project. Their constant encouragement and co‐operation made this project a success.
We would like to express our sincere thanks to Vishal Projects Pvt Ltd, for providing us an
opportunity to complete our Industrial oriented project successfully, which is a part of course curriculum. This training would not have been successfully completed without the guidance and support of Mr.Suresh Kumar (Project Manager) and the entire Vishal Projects Team. We are deeply indebted to the project team members who were always ready to help us during project time.
M.PrithviRaj, K.CharanRaj, A.Sai Krishna, B.Navaneeth.
CONTENTS
SUBJECT
PAGE NO
TITLE CERTIFICATE ACKNOWLEDGEMENTS
CHAPTER 1: Introduction 1.1 Introduction
1
1.2 Defination
2
1.3 Scope of the work
3
1.4 Objective of disseratation
4
1.5 Organization
4
CHAPTER 2: Literature Review 2.1 Review of Literature
5-8
CHAPTER 3: Automation and Robotics in Construction Industry 3.1 Introduction 3.2 Need for robots 3.3 Factors affecting work schedule
9 9-10 11
3.4 Factors affecting production efficiency
11-13
3.5 Typical causes for low labor productivity
13-14
3.6 Cost of robotized work
15-16
3.7 Robots used in construction industry
16-21
3.8 Robots used in civil works
22-26
3.9 Automation in construction of roads 3.10 Challenges facing automation and robotics in construction
26-29 29-31
3.11 Evaluation for using robots and automation
31
3.12 Building management and security systems
32
CHAPTER 4: Application of Robotics in Construction Industry 4.1 Introduction
33
4.2 Concrete floor finishing
34-36
4.3 Partition masonry
36-37
4.4 Plastering
37-38
4.5 Painting
38-40
4.6 Discussions
40-43
CHAPTER 5: Scope for Future Work
44
CHAPTER 6: Conclusion and Reference
45
ABSTRACT Robot system used in building construction sites can efficiently reduce construction time and increase safety by replacing human in dangerous operations. Construction robots are defined as field robots that execute orders while operating in a dynamic environment where structures operators and equipment are constantly changing. Robotic systems have become common in many manufacturing and production operations because they have proven to be more robust, safe, efficient, accurate and productive. Traditionally, the entire construction was dependent upon the traditional methods and equipment. Slowly the construction industry is mechanized and computerized keeping in view the time of completion of the project, shortage of labor force and quality of work to be executed. The rapidly growing construction industry is now looking into the robots for different works during execution. The limited experience of applying robots to construction, together with conclusions drawn on the basis of robotic application in related areas, show that developing efficient robotic systems alone will not ensure successful implementation. However, it is only recently that the subject has begun to emerge as a coherent but multidisciplinary activity. Although the construction industry so far has managed to develop highly productive systems without the help of robots, there are specific areas of application in which robots could benefit the industry. Newly, developed construction systems should achieve the building design and construction planning just suited to robots. In this dissertation the description of a concrete‐floor finishing robot, partition masonry construction robot, plastering robot and painting are described which help a human operator to perform their respective tasks on construction site. Feasibility of using robots in building construction is determined from comparison of robotic versus manual performance of pertinent building tasks. The following study presents a quantitative assessment of two aspects of robotic feasibility: saving in human labor and its impact on costs. The objective of this dissertation is to study the feasibility of robots in construction industry. This dissertation compares the traditional and human operated systems with autonomous systems and provides a set of guidelines for developing future equipment more economically.
CHAPTER 1 INTRODUCTION
1.1
Introduction
Construction is an old profession and could be taken back from the transformation of a primitive man to a different standard of living. The construction industry employs a large labor force, next only to agriculture. Development of the construction industry in our country like other industries is very slow and less systematic till 19th century. It is in the current century, the large scale mechanization brought changes in the building practices and in the management of construction jobs. This depends on the optimum use of resources such as men, machines and materials. In spite of considerable mechanization in India, there is a large amount of manual labor in the construction sector.
Even since the dawn of civilization, man has indulged in some form of construction activity. The term “construction project” refers to a high value, time bound and special construction mission with predetermined performance activities. Today, the construction industry is an important index of social and economic development in the nation. The major portion of total outlay in any five year plans is utilized for construction activities. Since independence in 1947, the construction industry in India has undergone the large scale mechanization with rapid changes and advancements in construction practices as well as in the management of construction works.
Dams, power stations, underground works, subways, marine projects, airports, thermal stations, transmission lines, industrial buildings, high rise buildings, housing projects, hospitals, educational institution, post offices, commercial recreation facilities, are some of the important activities of construction. High risk and pit falls in the industry plays a huge demand on safety involved in the construction industry at various levels. The construction industry employs an average of 5% of the local labor force and accounted for about 11% of all occupational injuries and 20% of all deaths re4sulting from occupational accidents. Keeping in view safety, shortage of skilled labor force, time to complete the construction and working space all around the building, it’s time to think alternative solution.
Shimizu Corporation of Japan began its research and development of robotics in 1975 to advance innovation in construction production.
The following section summarizes the company’s progress in R&D in various areas in building construction. a) b) c) d)
Fire proofing spray robot (SSR-3) Ceiling-panel positioning robot (CFR-1) Concrete-floor finishing robot (FLATKN) Wall-finishing robot (OSR-1)
Properly designed robots produce a high quality product than humans and building owners are more satisfied with final product. Therefore, contractors should enjoy a better relationship with their clients and expect to be invited back for additional projects. Additionally by using robots the builders are less likely to experience call backs to replace defective workmanship. Thus, accidents caused can be reduced if robots are utilized in place of humans. Although the robotic technology can benefit construction industry in many ways, it is not cheap, especially for applications in the rugged outdoor environment. Robotics research is multidisciplinary and involves high technology and machineries that require special training to operate and maintain.
Construction automation and robotics have been generating much interest in the construction community for the last two decades. Early development of onsite robotized concepts started to emerge and even been tested over fifteen years ago. Atomization and Robotization of the industry was started in 1980’s in Japan. The first ISARC (International symposium on automation and robotics in construction) was started in the US in 1984. Then the symposia were held every year in many countries in turn. The international Association and Robotics in Construction (IAARC) was started in1990, and association has helped Automation and Robotization of construction greatly.
1.2
Definition
A building robot was defined as an automated device employed to perform a building task in a construction site. The definition is synonymous with the one in encyclopedia Britannica : “automatically operated machines that replace human effort”. Automation in a more general sense of preprogrammed autonomous activities. A robot may be defined in general terms, as a
reprogrammable, multifunctional manipulator designed to perform a variety of tasks. In other words, a robot is a mechanism guided by automatic controls.
1.3
Scope of the Work
Robots have been designed to support human beings by helping them to do tedious, dangerous and back breaking works. However, the construction industry has made only limited use of high technology production concepts. There is general need to nurture the development of successful research and development programs in Construction Automation and Robotics. Building robots have been employed in various tasks, including materials handling, various interior and exterior finishing tasks and quality control. The high expectations of building robotics stemmed from the very serious problems the industry is facing : • • • • •
Continuously declining productivity A high accident rate Low quality Insufficient control of the construction site Vanishing of a skilled workforce
In recent years, the use of new technologies within the construction industry has shown great potential although little has been implemented. For example, robotic systems and other programmable machines are needed to perform tasks that involve hazards or are in some way physically dangerous to humans. The development of robotic systems in construction advances very slowly owing to several challenges. One of these obstacles is the development of the required software components. Such development represents a big obstacle because of the requirement for highly trained programmers and expert software engineers.
The present level of on-site of robot employment is less. The reasons for this situation are identified as follows: ¾ ¾ ¾ ¾
Existing robots are not well adapted to building construction There are problems associated with the conventionally designed building It is difficult to justify robot employment economically There are managerial barriers. Consequently, recommendations are offered for more efficient future implementation.
The six main parameters that can sufficiently define a construction project are size, complexity, quality, productivity, completion time and cost. • •
• • • •
Size denotes the number of tasks to be executed in a project and each task is measured in terms of quantities of work involved. Complexity is a measure of variety in the nature of tasks to be executed i.e., complexity increases as the number of dissimilar task increase and it decreases if the tasks are repetitive or similar in nature. Quality to be achieved in accomplishing tasks is stated in terms of standard specification. Productivity, in its broader sense, measures the ratio of planned effort to produce unit quantity of work divided by the actual effort employed to achieve this unit of work. Completion time depends upon the speed with which the project is to be executed Cost is the expenditure which the client has agreed to commit for creating the desired construction facility.
1.4 Objective of the Dissertation The general objective of the thesis is to determine the scope of application of robotics in building construction. In more specific terms the objectives of the thesis are: ¾ ¾ ¾ ¾
To review the literature for implementation of robotics in building construction. To identify the feasibility of using robots in building construction. To reduce time and save cost in building construction using robotic applications. To draw conclusions regarding the extent of success of building robots.
1.5 Organization The thesis consists of 5 chapters. • • • • •
Chapter 1 is introduction part and includes definition, scope of work and objectives. Chapter 2 is review of Literature. Chapter 3 is Automation and Robotics in Construction industry, it includes need for robots, factors affecting work schedule, production efficiency. Chapter 4 is application of robotics in construction industry; it includes research methodology, case study, calculations and discussions. Chapter 5 is conclusions and includes recommendations and future scope.
CHAPTER 2
LITERATURE REVIEW
2.1 Review of Literature Development of robotic systems for construction application has advanced dramatically over the past few years (Thompson 1994). Robotic systems were initially developed to reduce labor requirements, shorten construction time and reduce costs and quality. The high expectations of building robotics stemmed from the very serious problems the industry is facing, continuously declining productivity or, as stated by Whittaker (1986) labor efficiency is alarmingly low in construction “a high accident rate; low quality; insufficient control of the construction site; and the vanishing of a skilled work force.”
A report describing cases in which robots were already performing economically useful tasks in the field for Japanese construction contractors (“Japan” 1913) gave rise to a feeling that construction robotics had become a reality. On the basis Paulson (1985), in a review and analysis of the emerging technologies, concluded that perhaps in no significant research effort evolves in the U.S. American contractors will be able to solve their problems by importing robotics and process control machinery from overseas. Ueno et al (1986) after being engaged in the development and on-site application of construction robots for over a decade came to the conclusion that “the period in which construction robots are adopted as a curiosity is almost over in Japan”.
Whittaker and Bandari (1986) were already looking at the next stage of construction robotics, in which a number of robots would work together. They reported that “robots were emerging in construction as a way to increase productivity, improve quality and decrease hazard to human workers”.
Skibniewski and Russell (1989) say, “with less optimistic estimates for construction robotics due to their operational environments, it can be anticipated that this application can result in approximately 10-15% increase in the overall construction productivity rate”. In (1992) reported on early application in the United States, saying that “the process of dissemenati9ng the early results from research and development of construction automation and robotics into industry practice is now slowly taking place. A number of robotic prototypes have been designed and built in the U.S; some of them have nearly found commercial application.”
Shortages have become so severe that construction firms are using temporary labor agencies to fill gaps with possible (Winston, 2000). Moreover, the current workforce is aging at a rapid rate. Many young people consider construction work to be dirty and undesirable. A survey of 10,000 high school students found construction ranked 251 out of 252 possible career choices (Donohue, 2000).
Robots can perform many of the more dangerous work operations without risk (Bares, 1999). For example, workers can remain on the floor below as robots spray polyurethane foam roofing materials to seal he structures above. Thus, builders are not exposed to fall hazards or breathing hazardous materials in the air (Nestle, 1999). It is now time for the U.S. construction industry to consider robotics as an answer. But getting large0scale automation systems on the construction site remains a challenge (Phair, 1997). According to Seward (1992), the Japanese have a liberal interpretation of the term “robot”: their definition includes advanced automation and remote control devices on the construction site or prefabrication shop.
Warszawski (1994) described the implementation of robotics in building. A survey to evaluate the state of the art development and employment of building robots was conducted world-wide among construction companies, universities and other research organizations. The analysis of the results yields a gloomy picture of the present level of on site of robot employment. The reasons for this situation are identified as: the existing robots are not well adapted to the building construction, there are problems associated with the conventionally designed building, it is difficult to justify robot employment automatically and there are managerial barriers. Consequently, recommendations are offered for more efficient implementations.
Boyer (1990) stated that the role of construction engineers and management researchers in automation and robotics may be best described in terms of the four overlapping elements of scholarship as: discovery, integration, application and teaching. One is tempted to view the scholarships of discovery, integration and application as if they should occur in the sequence as presented.
Demand on market-pull is the demand or “necessity is the mother of invention” side of innovation. Here the problem leads to solution (Nam and Tatum 1992; Rosenberg 1982).
Robotics systems were initially developed to reduce labor requirements, shorten construction time, reduce costs and improve quality. Benefits such as elimination of dangerous work areas for employees and conformance to standards of the Environmental Protection Agency, the Toxic Substance Control Act and the Occupational Society and Health administration have improved the worker’s environment and morale (Thompson 1994). Since the benefits of robotic applications are significant, researchers have conducted studies to determine which construction tasks might be suitable for robotic applications. Most of the studies have concluded that the application of the surface coating is very suitable for robotics (Skibniewski and Hendrickson 1988). To date, few robotic applications are in actual field use (Boles et al. 1995; Everett and Slocum 1994). Ueno (1994) who said in 1986 that construction robots would not be just a curiosity now says that most of construction robots will not be widely used because of their high costs and low performance. He says that most of the single task robots in Japan are teleoprated. Ref.37, a report on the 13th international Symposium on robots, states that “of the 260 robots on display, not one was earmarked for construction applications.” Although construction is considered by some as the largest sector of the U.S economy, robots have several reasons for shunning this market. According to David M. Osborne, technical director of Swedish ASEA’s Troy, Michigan, office, “construction jobs are not always the same, so there’s not a great deal of repeatability. Most construction jobs require a certain amount of on-site judgment, which a robot can’t provide.
Another Japanese view is that “only a few construction robots have been made commercially available for the execution state of construction, because many of them are stalled at the demonstration stage” (Obayashi 1992). Furthermore, “most of the commercialized techniques replace hand work by machines, which mean that they do not have the desired effect that could be achieved from high-tech systems”. (Obayashi 1992)
With respect to automation and robotics, managers’ and owners’ demands included increased productivity, increased speed of construction, improved quality and improved safety, constructability and project economy. (Arditti et al. 1990)
Need is a motivating factor in robotization of construction operations. If need is sufficiently great, the economic payoff will offset the development expense required to overcome technological barriers. Tucker (1986) for instance, has noted that the major cost center
in industrial construction is piping. If the fabrication and erection of piping can be improved by automation, the economic benefits can be calculated.
The automation of robotization of a selected process must be technologically feasible within the context of the existing or projected state of the art in robotics. The technological evaluation for a construction process must consider both technology and development trends in robotics research. (Reinschmidt 1986).
CHAPTER 3 AUTOMATION AND ROBOTICS IN CONSTRUCTION INDUSTRY
3.1 Introduction Intense competition, shortages of skilled labor and technological advances are forcing rapid change in the construction industry, motivating increased attention on construction robotics. The introduction of robots for some skilled and unskilled tasks might improve productivity and save construction time by increasing pace of work. Robotics in construction industry is a fast growing interdisciplinary field. Robot application in construction can be classified into two types. One type is replacement of highly labor-intensive, repetitive and simple operations and other is performance of operations that pose a health hazard to human workers. Such hazards can be associated with work in under seas, on chemically or radioactively contaminated sites and in regions with harsh climates.
A construction robot can be used to increase productivity, decrease cost, improve work pace and quality helps to avoid work related injuries and reduce medical cost. The robots employed in construction have followed the same concept as those employed in manufacturing. Most of them use an effect or (a gripper or a work tool) mounted on a multi axial arm, and their tasks are defined and controlled by computer. However unlike most of the manufacturing robots, which perform preprogrammed tasks from static work stations, the construction robots have to be mobile and, when fully developed, will have to interact with the changing environment through sensors, adapting their tasks on the basis of the feedback received.
3.2 Need for Robots Fast changing, field-based, project-oriented industries like construction are severely handicapped by their lack of accurate, timely and systematic technical, cost and production data from ongoing operations. Meanwhile, technologies have evolved that can not only monitor the ongoing operation of manufacturing facilities and collect operational and passenger volume data from transit systems, but can monitor vehicle operations characteristics, transit high resolution video images.
The conventional process of executing the construction work requires highly skilled workmen in order to achieve sufficient and consistent quality. This labor-intensive construction
process results in relatively high cost. To achieve higher rationalization and humanization, different methods have been tested. For example, one of the approaches, which are used by the sand-lime brick and cellular concrete industry, is the enlargement of the size of the building blocks. The enlarged dimensions of these blocks, however, coincide with their increased physical weight up to 300 kg. Due to their larger dimensions and heavier weights, these building blocks are not ergonomically desirable and, therefore, various mechanical aid devices such as hydraulic balancers or mini cranes with counterweights are used for the assembly.
Another tendency which is steadily gaining momentum is the use of exact, plane parallel blocks which are laid on a thin mortar, respective glue bed with concrete. These methods also offer better physical properties like heat insulation and bigger load bearing capacity because of the lack of the mortar joints. Because of the reduction of the walling operations, they enable higher working speed and easier use. A first layer of smaller blocks in a more or less thick mortar bed usually compensates for the different inaccuracies of the floor. By applying this method, the difficult alignment that is required for adjusting the position of each block can be reduced. Though an increment of the working speed can be achieved even by employing less qualified workers on the construction site, the present and future share of the costs due to labor will be constantly increasing.
Other existing approach needs some degree of automation. Certain activities, such as the cutting of the blocks, can be transformed from the construction site to the building material factory. Precutting of blocks simplifies the work, avoiding transporting the bigger cutting equipment. However this method leads to marking the blocks and delivering them together with an assembly plan, which shows the positions of the respective blocks in the wall. Thus, information technology for the creation of assembly plans and for the control of the cutting equipment is necessary.
Further rationalization can only be achieved by the reduction of labor and construction times. Since the above mentioned mechanized methods for masonry have reached their limits, they cannot contribute to further effectiveness and therefore a certain innovative leap is required by a system approach that combines the already existing construction technologies with new information and robot technologies. Robot assembly system for computer integrated construction project deals with the development and realization of integrated automation system. Thus, conventional control strategies are unsuitable and prove completely insufficient. New control methods are identified in order to achieve high performance with a reasonable time consuming algorithm, which is useful in real time control system.
3.3 Factors Affecting Work Schedule The scheduling of a project plan has to take into consideration many variables like time, resources and financial constraints. It is difficult to enumerate principles governing all such factors which may vary from project to project.
3.3.1 Time: The availability of time is a crucial limiting factor in a project. More time normally implies less investment.
3.3.2 Manpower: Manpower is one of the main factors in the successful execution of the project. The idle labor time is paid for and the strikes and the breakdown of work are kept in view by the management. The task efficiency of the labor wealth conditions, nature of work and the supervisors, leadership, all of these effect labor productivity. The non availability of suitable labor is generally, a limiting factor. The labor turnover, sickness and absenteeism further aggravate the problem.
3.4 Factors Affecting Production Efficiency The computation of the production efficiency factors depends upon numerous variables which affect workers productivity in actual job conditions at the project site. These variables vary from project to project, and over place and time. Some of the typical factors affecting the workers production efficiency are given in following:
3.4.1 Work Complexity: A simple, familiar work is easier to execute than an unfamiliar complex one. The extra effort needed for the latter type of work, especially in the initial stages, may range from 10-100% of the normal expected productivity.
3.4.2 Repetition of Work: While the first time execution of an unfamiliar work needs extra effort and results in the low output, the skill acquired in the process, when utilized over a period of time to execute similar works, improves productivity rate, when crew of the workers is the same. This improvement in productivity rate continues till certain limit is reached.
3.4.3 Equipment-Intensive Tasks: The construction equipment executes work speedily, but it needs operators. The productivity of man-machine combination depends upon many factors. However, the equipmentintensive tasks are less susceptible to productivity changes than the labor-intensive ones.
3.4.4 Climatic and Weather Conditions: Generally, under average weather conditions with temperature from 40-70 degrees Fahrenheit and relative humidity of 60% the workers continue working at the same productivity level. But extreme situations and seasonal changes like hot and cold climate, high humidity, and strong winds and rains affect both productivity as well as work performance.
3.4.5 Labor Availability: The labor productivity also depends upon employment opportunities available in the market. If jobs are plenty and labor is scarce, the labor productivity tends to become less. During a slump in the construction market, labor is easily available while there is a dearth of jobs. In such situations, employers can afford to be selective as hiring and firing of workers become easy. In scarce job situation, the overall productivity improves since the employers can then sort out labor with a light productivity. There is also a tendency among labor to move to high value, large size projects since they offer them longer service, better job opportunities and more stability.
3.4.6 Scheduling Direct Workers: The project direct manpower constitutes a major portion of the labor strength. Since activity has a specified duration, work content and manpower required for its accomplishment, the daily average manpower required for each scheduled activity can be assessed as: Manpower req. = Quality of work × labor productivity standard in man – days / duration in days.
3.4.7 Adjustment for Daily Manpower Requirement: The factors such as learning process, weather conditions, labor turnover, strikes, absenteeism, sickness and the overtime working policy affect the day to day aggregated manpower requirement. Replacing unskilled labor by machines wherever feasible, in jobs like loading, unloading, shifting, bar - cutting, etc.
3.4.8 Selecting Construction Equipment: Equipment purchase involves initial heavy investments. In the long run, equipment adds to the profitability by reducing the overall costs, provided the equipment is properly planned, technically scrutinized, economically procured and effectively managed.
3.4.9 Equipment Output Capability The equipment performance at the site work depends upon many situational factors that influence the output. These situational factors may include the equipment serviceability conditions, the effect of terrain, the accessibility to work site, working conditions including timings, logistic and equipment vendor support and the availability of local resources like operators, equipment renting facilities, power and supply, fuel and lubricants, etc,.
3.5 Typical Causes for Low Labor Productivity 3.5.1 Worker’s Low Moral: This can result from: • • • • • •
Non-fulfillment of employment terms and conditions by the management. Insecurity of employment. Sub-standard working conditions. Frequent transfers. Frequent changes in the scope of work and work methodology. Conflicts between supervisors and workers.
3.5.2 Poor Pre-work Preparation by Supervisors: The lack of preparation for the execution of the assigned work prior to commencement can result in insufficient handling of resources due to: • • • • •
Excess workers employed for the task. Insufficient instructions for the execution of the work. Incorrect sequence of work activities. Shortage of tools and materials at site. Wastage resulted from unnecessary frequent shifting of materials and making and breaking of poor quality / defective work.
3.5.3 Directional Failures of the Project Management: These include: • • • •
Failure to set performance targets. Failure to make provision for timely resource support. Failure to provide feedback. Failure to motivate workers.
A great responsibility lies on the shoulders of construction engineer in converting plans and specifications into a finished product at the lowest possible cost. So the construction is the ultimate objective of the project. If the construction is carried out properly all the beauty of planning and all the soundness of the design will mean little.
All over the globe, the construction activity is getting increasingly complex day by day. Rapid improvement in design and technology has added new dimensions to the industry. The dearth of the right type of skilled labors and the rapid increase in the cost of labor wages and also magnitude and the nature of the jobs involved, have led to new techniques in the construction with their inherent problems of adaptation to change. The continued exploitation of labor in the past has increased worker discontent and has opened out new areas of conflict. The need for the better construction practices, systematic planning and programming of works and effective management in the industry is therefore the demand of the day.
3.6 Cost of Robotized Work The total cost per unit of robotized execution of a building task is composed of the following: • • •
• • •
Direct cost of robotized work. This cost depends on the direct cost of time input per work unit and the cost of the robotized system per hour. Cost of materials per unit, in robotized work. Cost of auxiliary manual labor, such labor may need for the materials handling, work area preparation, and some improvements or additions to the robots work. Its cost depends on the required time input of manual work and its cost per hour. Cost of the robots movement between workstations. This cost depends upon the distance the robot has to travel, its speed of movement and the cost of the robotized system per hour. Cost of robots positioning at each workstation. This cost depends upon the time setup and the cost of the robotized per hour. Cost of robots transfers between different work areas on site. This cost depends upon the number of transfers, the time required per transfer, the cost of the robotized system per hour, the cost of the other resources involved in the transfer.
The cost per hour is identified using the following formula
C = (P X Pr (I, N) + Cm) / H + Co
Where;
P is investment in the robot (including the cost of carriage, effectors, sensors & other adoptions). Pr (I, N) is the capital recovery factor (depreciation and interest factor, assuming annual interest I and economic life in years). Cm: Cost of repairs and high level maintenance of the robot per year. Co: Operating costs (including some effected parts) per hour and H: number of robot employment hours per year.
The major parameters determining the cost of the robotized work can be therefore divided into three main groups: 1. Parameters dependent on the robotic system include cost, its work envelope, its speed of movement and its mode of operation 2. Parameters dependent on the nature of the building site include the nature of the tasks to be performed, their quantity, the number of transfers between work sections and the location of the work in each section. 3. Parameters dependent on the tasks to be performed include the output per hour, the materials and the auxiliary works needed.
3.7 Robots Used in Construction Industry: Robotics and automation are expected to play an increasingly important role in the construction industry in the next decade. Due to the dynamic and unstructured nature of the construction environment, research and development (R & D) in the application of high technology is needed. Recent progress of robotics in the other industrial fields has shown a great possibility to promote the automation of the complicated construction processes. Shimizu Corporation of Japan began its R & D of robotics in 1975 to advance innovation in construction production. The company’s rationalization for R & D in construction is to increase productivity, improve quality, reduce cost, increase efficiency, obtain new markets and improve safety of the construction work environment. The ultimate goal is to create a flexible and integrated environment of the construction projects. The company has focused on both of these areas, automating traditional construction sites and new construction fields. The following section summarizes the company’s progress in R & D in various areas: 1. 2. 3. 4. 5.
Fireproofing spray robot (SSR-3). Steel-beam positioning manipulator (Mighty jack). Ceiling-panel positioning robot (CFR-1). Wall-finishing robot (OSR-1). Spray-coating robot (SB-Multi Coater).
3.7.1 Fire Proofing Spray Robot (SSR-3) Rock wool spray work for fireproofing steel structural members is a hazardous construction job. The SSR-3 was developed to provide a safer work environment for spray workers. While spraying, the SSR-3 moves parallel to a steel beam at a constant distance measured with a pair of ultrasonic sensors. Compared to conventional methods, the work
environment is improved and work speed is increased without the use of scaffolding. The SSR-3 robot is designed to spray fireproofing material onto structural steel frames. The fireproofing spray robot is shown in the figure 3.1 and figure 3.2
Fig 3.1 Fire Proofing Spray Robot.
Fig 3.2 Application of Fire Proofing.
3.7.2 Steel-Beam Positioning Manipulator (Mighty Jack) Steel-Beam erection work is one of the most dangerous tasks on the construction to be robotized. Steel-Beam positioning manipulator lifts two or three steel beams and sets them in the correct position by teleportation. While setting beams, the manipulator grasps the top of the columns and there is no need to be lifted by a tower crane. This means that the tower crane can be used for the other jobs while the manipulator is working. It weighs a total of 1,900 kg with a hanging load capacity of 2,100 kg and one degree of freedom. The steel-Beam positioning manipulator is shown in the figure 3.3.
The positioning and assembly work of the beam is carried out by the manipulator as follows: 1. 2. 3. 4. 5. 6. 7. 8. 9.
Set grippers at the suitable position. Put cables on steel beams. Position the manipulator with beams using a tower crane. Place the manipulator on the top of the two columns. Release tower crane cables from the manipulator. Adjust the distance between the two columns. Set beams in the correct position one by one. Connect beams to columns and Lift the manipulator to perform the next cycle.
Fig 3.3 Steel – Beam Positioning Manipulator
The mighty jack has been applied to several construction sites. It takes about 25 minutes to assemble six beams. It takes about 40 minutes for the same work using the traditional method. Furthermore, assembly work can be accomplished much more safely and efficiently using Mighty Jack. Redesign of structural steel for automatic assembly and improvement of the system’s versatility are the future research themes for the Mighty Jack.
3.7.3 Ceiling-Panel Positioning Robot (CFR-1) Ceiling construction for office buildings, hostels and other commercial buildings is accomplished by using plaster-board panels, which are made of plaster and covered with paper. A typical midsize office building, for example, with eight floors and 5,000 sq m requires 400 panels for each door. The procedure for ceiling construction requires temporary scaffolding to be erected over the floor and then cleared away for next procedure. The workers must raise heavy, large panels over their heads for placement against the hanging ceiling flat bars. Repetition of this work over a long period of time exhausts workers. The Ceiling Panel Positioning robot is shown in the figure 3.4.
Fig 3.4 Ceiling Panel Positioning Robot
The CFR-1 consists of a robot and a panel carrier which can be separated easily when transported. The robot is composed of a base frame with a travelling device and an X-Y horizontal table, a lifting arm with a panel holder and control box. The CFR-1 weighs 300 kg and
has 4 degrees of freedom, a carrying capacity of twenty panels, a work capacity of 25 panels /hour and a working travel speed of 3m/min. Ceiling construction work using the robot is accomplished as follows. The fully loaded panel carrier is attached to the robot and the robot is positioned under the location where the panel will be set. The robot uses the panel holder to remove one panel from the panel carrier, and then lifts it into position among hanging ceiling flat bars. The robot places the panel in the correct position using the X-Y horizontal table automatically assisted by the complain mechanism. Then the worker fixes the panel using an air screwdriver. The robot travels to the next position to set the next panel. The CFR-1 raises a ceiling panel and positions it correctly. Operation of this robot is easy and good positioning accuracy is realized without skilled workers.
3.7.4 Wall-Finishing Robot (OSR-1) OSR-1 (Ohi Saikaihatsu Robot) is an automatic spray-painting system for the high-rise residential buildings. Conventional painting work has resulted in accidents when objects fall from high scaffolding. The OSR-1 is developed to decrease such accidents and to realize uniform spray quality using robot. Moving along the handrail on the wall, the OSR-1 extends its multi axis arm. A spray nozzle moves up and down on the end member of the arm. The arm avoids obstacles, such as pipes located along the wall and moves its spray nozzle parallel to them.
In conventional construction, finishing work is generally carried out by skilled workers operating from scaffolding. The introduction of this robot makes scaffolding unnecessary and decreases the exposure of workers to dangerous conditions.
The robot consists of a travelling device, control device, horizontal arm, vertical arm and guiding device. A spray gun moves up and down along the vertical arm. The spray work is carried out by this vertical action with interval travelling device. The travelling path is controlled by the guiding device, which uses a handrail as a guide. At an uneven part, the robot rotates the horizontal arm automatically, according to the program. It weighs 223 kg and has a maximum travelling speed of 20 m/min. The Wall Finishing Robot is shown in the figure 3.5.
The OSR-1 was applied to work at a condominium at Ohi in Tokyo. At this site, the process of finishing work consisted of three parts: undercoating, tile spraying and top coating. The production capacity of this robot was 80 sq m per day using three workers. The conventional manual method requires four workers for the same production. Labor savings, improvement of safety and elimination of scaffolding are the main advantages of this robot.
Fig 3.5 Wall Finishing Robot
3.7.5 Spray-Coating Robot (SB Multi-Coater) The SB Multi-Coater is an automatic sprayer for exterior wall painting, which can perform spray coating on exterior walls of medium and multistory buildings. Their main purposes are sealer coating, material spraying and top coating. It needs only one operator on the ground and provides an enhanced production rate about five times that of conventional methods. It gives an excellent finish comparable to skilled workers. The SB Multi-Coater provides a smooth, evenly sprayed surface. It performs spraying by moving right and left with one or two spraying guns rotating at high speed in a uniform pattern during the main material spraying process. There are five types of basic patterns in wall finishing. Suitable patterns are selected according to the materials to be coated. The SB Multi-Coater can spray the main elastic coating material at approximately 400 sq m per day as opposed to the daily production rate of the conventional methods, approximately 80 sq m per day. The Spray-Coating Robot is shown in the figure 3.6.
Fig 3.6 Spray Coating Robot
3.8
Robots Used in Civil works
3.8.1 Semi Autonomous Robot: Navigation and tele operation are the special features in this mobile robot prototype. This can be used for indoor and outdoor works. The Semi Autonomous Robot is shown in figure 3.7.
Fig 3.7 Semi Autonomous Robot
3.8.2 Brokk Machine Equipped with Hydraulic Breakers: This produces exceptional punching and works for stripping out walls and floors of building site and has break out force equivalent to conventional 5 tone excavator. The Brokk Machine equipped with Hydraulic Breakers is shown in the figure 3.8.
Fig 3.8 Brokk Machine Equipped with Hydraulic Breakers
3.8.3 Concrete Crusher: It is faster and quieter robot to demolish the concrete. Adjoining work can often continue uninterrupted and emollition can even take place at night. The Concrete Crusher is shown in the figure 3.9.
Fig 3.9 Concrete Crusher Robot
3.8.4 Demolition Robot: It is used in the confined space and selective demolition works. The precise control enables demolition needed sections, while leaving the remaining sections un scattered. The Demolition Robot is shown in the figure 3.10.
Fig 3.10 Demolition Robot
3.8.5 Brokk Robot for better work environment: They are useful for better work environment, where there will be no exhaust fumes, no vibration injuries, good operator visibility and insignificant risk of injury from falling objects. The Brokk Robot is shown in the figure 3.11.
Fig 3.11 Brokk Robot for Better Work Environment
3.8.6 Robot for All Jobs: It is employed for chiseling up-channels in the floors to allow the replacements of the drains, removing tiles and clinker and it is shown in the figure 3.12.
Fig 3.12 Robot for All Jobs
3.8.7 Robot for Renovation of general areas: This is employed where the renovation is most common in the large urban areas and it is show in the figure 3.13.
Fig 3.13 Robot for General Areas
3.8.8 Robot for Cement Industry: It is employed for stripping linings and cleaning kilns even the kiln has completely cooled down. Robot for Cement Industry is shown in the figure 3.14.
Fig 3.14 Robot for Cement Industry
3.8.9 Robot for Blasting: It is employed for blasting away the surface duly undamaging the underlying surfaces. It is shown in the figure 3.15.
Fig 3.15 Robot for Blasting
3.9. AUTOMATION IN CONSTRUCTION OF ROADS Road paving robots show high level of automation through providing the followings - automated reception of asphalt - automatic control of asphalt conveyance - automatic control of asphalt spreading - automatic steering control with mechanical sensor and automatic control of paving speed - automatically controlled start/stop of all paving functions
In addition, tasks can be performed automatically based on an artificial vision and a laser range sensor. Hence, graphical remote control system let human operator control more the fixing process, while reducing the need for range sensors
3.2.1 Figures of Robotic machinery used In automated road construction
Fig 3.16 : Concrete Horizontal Distributor
Fig 3.17: Attaching the ceramic tile with hybrid construction robot system
Fig : 3.18 Concrete Floor Finishing Robot
Fig 3.19: Systematization of concrete construction work
Similarly, Longitudinal Crack Sealing Machines can fill and seal cracks running along the road, for example between lanes and the shoulder. The process is remote-controlled by the driver, and the machine can fill cracks at up to five miles per hour. In comparison a manual sealing operation would take a large crew all day to complete two miles. Robots are also helping to remove roadside litter and debris, another hazardous, labor-intensive operation
3.10 CHALLENGES FACING AUTOMATION AND ROBOTICS IN CONSTRUCTION The primary contribution of automation in construction is the development of a comprehensive, multidimensional analysis of costs and benefits associated with a specific robotic application. It is quite important to analyze success through the technical and economic feasibility. The technical feasibility is determined by an ergonomic evaluation of individual steps taken to accomplish the given work task, and by analysis of the requirements for robot control and process monitoring. The economic feasibility, which is perceived to be the decisive factor in the market success of the proposed robotic systems, is determined by the analysis of the costs and benefits associated with their development and field implementation. Specific technologically challenging process and characteristic of robot construction applications include:
- Performance in a harsh work site environment, or undefined and sometimes hostile conditions such as: - Difficult climatic conditions - Exposure to dust - Calibration in relation to environment - Adjustment to changing surface conditions - Complexity of the working environment - Some changes in the nature of the robotized work process versus the traditional, humanperformed work process. - Real-time “Sense-and-Act” operation for mobile construction robots to perform accurate and/or delicate tasks - Identification of various types of objects in natural environment conditions - Interactivity between sensors and end-tools
In contrast, a robotic system that would operate with no need for detailed pre-planning would be less technologically demanding and may, therefore, be easily developed during early stages of robotics integration into the construction field. The “Senseand-Act” process can probably eliminate the need for high accuracy when positioning the robot at its workstation, a fact that saves time and leads to greater economic feasibility of the system. Some researchers attempted to increase the autonomy level of robots by enabling them to map their environments and independently navigate through them. Although construction sites are characterized by inaccurate geometries, numerous obstacles, etc. the mapping and navigation methods may be adapted to it. Such navigation methods are expected to deal with these difficulties and succeed in achieving accurate enough results. Researchers and developers of autonomous robots have attempted to solve the problem of adjusting the robot to its environment by developing automatic mapping and self-positioning methods. The robot then autonomously navigates from one workstation to another.
Forsberg et al. suggested a plastering robot that uses a rotational laser beam to measure and map its surroundings (walls and openings). The mapping data was to be translated into a working plan, which would be presented to the operator for improvements. The suggested system
depended on accurate navigation methods, and was supposed to bring the robot to within ±1 cm of its workstation
Beliveau described an orientation system for indoor automated guided vehicles (AGVs), using three laser transmitters accurately positioned on the floor at known points. Experiments with this system revealed that the deviation of the measured path from the desired path was ±10 cm
Shohet and Rosenfeld examined the accuracy achievable by automatic mapping of indoor construction environments. It was found that when robot positioning was precise (orientation and location errors of 0.2° and 3 cm, respectively), the achievable accuracy of indoor environment mapping was 3–5 cm. This degree of accuracy is sufficient for tasks that do not require contact with the treated element (e.g. spraying). However, tasks that involve precise placing of elements (e.g. block laying and tiling) require a mapping accuracy of 2–3 mm, as well as the utilization of well-controlled end-tools
Yet, it is clear that these methods are not likely to conform to the accuracy requirements of many construction tasks. Moreover, even when correct positioning of the robot is assumed, accuracy of the robot's arm, or even that of the interpretation of its environment, is not sufficiently reliable. The accuracy of the manipulator's moves may vary from cycle to cycle due to variations in the load at the arm's end and in the arm configuration. Creating a more robust arm, one that would be less sensitive to the varied loads would lead to heavier and more expensive robotic systems with lower economic feasibility.
3.11 EVALUATION FOR USING ROBOTS AND AUTOMATION Initially, robots were developed for the manufacturing industry and were intended to perform routine task in a very familiar environment. Unlike such robots, those designated for work on construction sites must be mobile, maneuver in changing environments, and perform a different task at almost every step. Construction engineering is changed by the application of more industrial production, sustainable production, mass individualization, and intelligent building to improve constructability. Therefore, recent research indicates that robot technologies can; in fact; significantly improve quality and equipment control in several construction automation applications. The ability to automate construction would be useful particularly in settings where human presence is dangerous or problematic; for instance, robots could be initially sent to underwater or extraterrestrial environments, to create habitats to await later human travelers.
3.12. Building Management and Security Systems
Surveillance for security purposes after the commissioning of buildings or large estate is required to ensure quality environment for the occupants. If the surveillance job can be done by robots, the efficiency can be enhanced, resulting in great savings of manpower and improved safety of the management staff. Furthermore, if the robot can retrieve commands from the building management system via a local area network (LAN), further savings in manpower can be achieved in terms of first-line fault attendance by human management staff[19]. The development of a particular security system where the compulsory safety helmet required for all workers in construction sites is used as the base to accommodate miniature positioning and communication instruments. The position and ID of each worker is sampled periodically and sent via radio to a monitoring station, where the information is compared to a database containing the tasks and processes being performed in the site. According to this, workers and machines' positions are known in each instant and risk situations may be recognized immediately and therefore damage can be prevented
CHAPTER 5 SCOPE FOR FUTURE WORK
It is important to know the real status of building robotics today to decide what future directions building robotics should take. In the light of this bleak present status, is there any future for robotized construction? The answer is, by all means, yes, but only if eh subject is approached in proper manner. Robots developed with due attention to these requirements will have a much better chance to survival. The robot has to be “site-friendly” i.e., well adapted to the particular conditions of the building site. This involves
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Its performance as a system. All aspects of operation, movement, materials feeding and transfer and their adaption to the particular conditions of a building site, must be taken into account in the development. Ensuring that its weight does not exceed the permitted level load. Its maneuverability, i.e., its ability to work capacity in restricted spaces. Its versatility, i.e., ability to perform different tasks, increasing the extent of its use. Its independence with respect to power and materials supply. Its sturdiness, i.e., the ability to operate in the rough conditions of the building site with minimum maintenance requirements.
CHAPTER 6 CONCLUSION AND REFERENCS
It is important to maintain the correct relationship between the speed of processing and the speed of material delivery is essential for automation in construction industry. Use of robots will directly or indirectly save builder/contractor/owner to face legal problem and also the given tasks can be completed at a faster rate. Although the robotic technology can benefit construction industry in many ways, it is not cheap, especially for application in the rugged outdoor environment.
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The economy of robot use requires a sufficient volume of appropriate work for their continuous employment. The main justification for such employment will probably be scarcity of local labor and the explicit and the hidden cost of importing foreign labor. At present the robots can be economically employed in the construction of repetitive buildings designed with due regard for robotics constraints, in sophisticated and high precision tasks and in dirty and dangerous building chores.
REFERENCES • • • • • • • • •
Amarjit Singh. (2004) “High Quality, Low Cost Architectural Flexible and Quick Turnaround Mass Housing for the World’s Billion”. Proc of International Conference on Advances in Concrete and Construction ICACC- 2004 Hyderabad. India pp.851-868. Crawford, F.S.(1988) “Culvert Whistlers Revisited”, Journal of Physics. 56(8), 752-754 Dereck Seward and Khaled Zied (2004), “Graphical Programming and Development of Construction Robots”, Journal of Construction Engineering and Management, ASCE. 65. Everret, J.G (1994), “Automation and Robotics Opportunities Construction Versus Manufacture”, Journal of Construction Engineering and Management, ASCE. 120(2), 443452. Farid, F. (1993), Journal of Construction Engineering and Management, ASCE. 119(2), 193195. Krom (1997), “Industrialization and Robotics in Construction”, Journal of Construction Engineering and Management, ASCE. 111(3), 260-280. K. K. Chitkara, “Construction Project Management”. 13. U. K. Srivastava, “Construction Planning and Management”. 78-79. V. S. S Kumar and Balaji Narsimhulu(1999), “Robotics in Construction Insdustry” . 1-3.
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