Edy Utomo1, Buana Ma’ruf2
1Pascasarjana, Teknik dan Produksi Material Kelautan, Fakultas Teknologi Kelautan, ITS-Surabaya
2Peneliti Utama, UPT Balai Pengkajian dan Penelitian Hidrodinamika BPPT, Surabaya
Email: firstname.lastname@example.org, email@example.com
Accepted: 5 Juni 2015; Revised: 18 Juni 2015; Approved: 23 Juli 2015
This paper discuss about the application of robotic system in shipbuilding process. The application is reviewed for welding, blasting and painting, either for open structure or closed structure (double hull). Several advantages and disadvantages of existing robotic application are reviewed for development application usage existing robot, such as using the humanoid concept. This study also propose several modification of existing robot application in shipbuilding. The result of the proposed concepts are equipped with analysis study whether in structural mechanic of the robot’s body and the most suitable system which can be applied.
Key words : Robotic for Industry, Shipbuilding Industry, Manufacturing Automation, CAD-CAM.
The development of science and technology that has progressed in recent years can provide benefits from all aspects of human life. As in the development of computerized science which gives the influence to carry out an activity automatically. With the aim to facilitate and streamline manufacturing activities, CAM (Computer Aided Manufacture) technology is implemented by involving computers. One of the most important scopes of CAM is the use of NC (Numerical controller), NC is a technique using instructions that are programmed to control the machine, other than that another significant function of CAM is in programming a robot (articlecad.com, 2014).
Industrial robotic systems are an important part of the CAD CAM process. Industrial robots can be defined as computer control with manipulators designed to mimic human movements, such as movements to carry out a number of different industrial tasks without human intervention (Hawkes. B, 1988).
As with the ship building process, some current work processes have been carried out automatically using a robotic system, such as welding, blasting and painting (Lee. D, 2014), as shown in Figure 1.
Figure 1 shows the process of welding, blasting and painting in ship construction. This paper discusses the application of the use of robotic systems in the manufacturing process in the ship building industry from several previous studies. The form of weaknesses and strengths of several robot systems that have been used are given and equipped in the form of development concepts in accordance with related references.
The use of robot systems in the ship building invoice process is divided into 2 parts, namely the use of robot systems in open structures and closed systems (Lee. D, 2014).
Several studies have been published on the application of robotic systems in ship building manufacturing processes, such as: Aqua blasting 2,500, which has a manually operated air-diesel package; The Nelco system, designed with ride-on blasting with a firing system, has a hydrolic crane used on the outside of the hull; The Android system, which was developed with a mobile system with a control range of 35 meters, has a manipulator arm lever, nozzle blasting and a vacuum system that functions as a cleaner; The Blastman system, developed by Rutarauukki, has room to avoid dust contamination due to blasting work (Lee. D et al, 2010).
In fact, some of the latest automatic robot system concepts have begun to be simulated to complement the shortcomings of the application of the use of pre-existing robot systems, such as the application of Seoul National University, Mechanical Aerospace Engineering, Naval Architecture and Ocean Engineering in collaboration with Daewoo Shipbuilding and Marine Engineering in the form of an automated robot system that does blasting work on closed structures for double-hull construction on ships (Lee. D et al, 2010).
Over the past few decades, research on robotics has had a considerable impact on the industrial field. In short, the achievements obtained from robotics research in industrial applications have a good impact in terms of creating work results that are much cleaner, the security side that has a small risk of danger and difficulties in the work process. Such as the application of shipyards, which allows much faster work done with a much smaller level of risk (Lee. D, 2014).
Apart from that, ships carrying liquid or bulk cargo such as LNG (liquefied natural gas), LPG (liquefied petroleum gas) and even types of bulk carriers built using double-hull construction pose complex problems in some areas. manufacturing processes, such as the process of blasting on closed structures of double-hull construction and creating health problems for workers, if forced to do work manually (Lee. D al al, 2010). Therefore several robot systems for application of work in shipbuilding are divided into robot systems for open structures and robot systems for closed structures.
Robots For Open Structures
To build a ship block openly, all the side parts of the transverse girder, elongated stiffeners and bottom plates are welded with the aim of uniting the components of the ship structure both manually and by using automated welding robots. As shown in Figure 2 below.
In this work situation (as shown in Figure 2), welding carriages provide a major role in efficiency and operate the welding resistance for long sections in the horizontal and vertical directions. Welding carriages are mechanical devices that have 1 axis or 2 axes for various purposes in welding. As shown in Table 1 (a). 1 horizontal axis fillet welding carriage will unite the boundary meetings on the stiffener and the bottom plate with each movement on the welding torch in the direction of the horizontal path.
The thing to note is that this part of the carriage system requires a very careful installation so that it can be precisely in the desired trajectory of the welding workflow. This robotic system requires installation and re-installation for different objects. Even for the same workpiece, the position between the workpiece and the robot installed will vary depending on how the conditions are required. Thus, this situation requires a set of flexibility and adjustments from the sensory system, including a more effective weld tracking algorithm, which allows the robot to adjust its path along the welding path.
Although the Carriage has the good properties of size, light weight and controller modulator design. Carriage is not suitable for use in more complicated jobs, such as welding U-shaped trails, and Carriage has limitations on the degree of freedom it has. Thus some shipyards add 6-axis manipulators to the robot combined with additional facilities such as Gantry cranes and Overhead cranes with consideration of accessibility under complex conditions on open blocks. As shown in Figure 3, 6R welding robot articulations are connected to the Overhead crane.
This robot system method does not support movement in all directions after the installation of the robot in front of the welding location, which is then difficult to do by welding workers. Apart from that the robot re-installation must require assistance from workers. Therefore improvements in production efficiency methods are needed.
Apart from that, because this robot system cannot do work on closed structural parts, the use of platforms that can move automatically is very helpful in automating welding work, such as using the RRX Platform (Lee. D et al, 2010). As shown in Figure 4 below.
Some problems in the application of automatic robots in jobs carried out in closed structures, such as blasting work using silica sand in a confined space that will produce a large amount of dust, this is done manually using a human operator, it will result in disease on the operator. Such as pneumoconiosis is caused by accumulation of dust from rust in the lungs, so this shows that automatic performance is needed based on a robotic system that can move inside closed blocks to carry out blasting work on all construction components of transverse and longitudinal stretchers in closed structures (Lee D et al., 2010).
Apart from health problems for operators, other problems that underlie the creation of automatic robots are as follows :
• Access the narrow hole through the manhole to enter the robot system.
• Work space requirements.
• Quite a number of structural components exist in a closed structure.
From previous studies, there are only a few research reports available for robotic systems that can be used in closed structure work, such as: Painting robot, developed by Hitachi-Zosen, a shipyard in Japan that is used to carry out painting work on the interior of the structure closed (Lee. D et al, 2010). As shown in Figure 5 below.
However, painting robots require greater entry access to 800 x 1600 mm, with manholes in closed structures measuring 600 x 800 mm, so these robots need to be disassembled into several sections before being placed into closed structures which are then put together (Lee. D et al , 2010).
IAI (The Industrial Automation Institute) in Spain, developed ROWER.1, as shown in Figure 6. This robot moves like a spider and has four legs that extend its contact area, can move on its own so that it can overcome many obstacles encountered in work welding in closed structures (Lee. D, 2014). But this robot must be dismantled into 7 parts to be put into a closed structure, which is then reinstalled into 1 part in a closed structure. So the need for a robot that has the advantage of ease to be able to enter through the manhole.
RRX and Incrotech, Korea, some time ago were developed to overcome problems in the welding robot system that had previously been developed, as shown in Figure 7. This robot system consists of a fanuc manipulator for welding the “U” plane, using a rail system in the direction transversely to be able to move inside a closed structural block, the box system on the rail is able to transport all welding equipment such as robotic manipulators, cables, controllers, welding machines and others (Lee. D, 2014).
In addition to use for welding work, a combination of the RRX mobile platform system combined with a robotic blasting manipulator is also applied, so that it can perform maximum work on the top plate and bottom plate in a closed structure (Lee. D et al, 2010).
RRX mobile platform, uses sensors to determine displacement in determining start and end positions. Generally the position of the mobile robot can be estimated through maps and various sensors with CAD (Computer Aided Design) information that has been made. This system is equipped with sensors that function to scan data in the work area.
Advantages and Disadvantages of Robotic Systems
The following shows a number of advantages in outline of the application of the automated robot system that has been applied to the shipping industry, including the following:
• The robotics system applied enables highly automated work, both for open and closed structures in ship construction.
• In a closed structure, the application of a robotic system from the RRX mobile platform, which is able to move by itself on the closed structure section has a positive impact on work.
• The development of robot technology used is getting better and better, this is indicated by the addition of 7-axis movement to a robot manipulator, which is used for blasting work in a closed structure.
• Some disadvantages from the work process carried out manually, have been proven to be eliminated by implementing a robotic system to replace the operator in direct contact with his field of work, especially in health issues.
• In general, the shape of the robot structure is very simple, but has a fairly good stability, which is evident from the results of dynamic stability testing on RRX mobile platform robot blasting.
Aside from the advantages of the existing robot system, there are also some shortcomings that are problems to be developed, including the following.
• Some robots, both for welding, blasting and painting work, have not found the use of control cameras, to be able to control the results of work remotely. However, it is equipped with sensors to read the surface of the plane of the work done.
• The dimensions of the robot which are inflexible and not whole can fit perfectly into the closed structure. Thus, the robot installation must be carried out in a closed structure.
• With a simple form but gives a good stability strength, of course this will produce a manipulator weight that is large enough, so that it will be a big burden on other structures in the robot system.
• For the RRX mobile platform mobile robot blast cleaning system, which is being tested on a new closed structure ship building, it is necessary to examine whether it is possible to carry out activities on closed structures on ships in repair conditions that have a greater level of dirtiness than new ship buildings.
Robotic systems are formed in such a way as to resemble movements in humans, to replace human labor and produce the effectiveness of a better production process, an industrial robot must be a mechanical structure (limbs) that can perform several movements in 3-dimensions. These robot movements are called DOF (degrees of freedom), (Hawkes. B, 1988). Most industrial robots generally combine one of the five basic system configurations of limbs movements, including: Cartesian, Cylinder polar, Spherical polar, Jointed-arm and SCARA (ntpel.ac.in). As shown in Figure 8.
The robot system itself in general has 3 basic components, namely; Manipulators, Controllers, Power and some are often found using Effector (tim.blogspot.com, 2012). The basic concept of a simple robotic component system, as shown in Figure 9. Input devices generally enter the robot’s brain in a variety of ways, either using the remote or given before the robot is activated, even found directly on the robot through its program.
In most industrial robots adopt the type of input device where the robot is activated then the robot will run what has been determined.
In addition, the robot can also receive input from the robot itself without human intervention, through sensors. The sensor on the robot is very helpful in detecting objects / components which are objects / work objectives of the robot according to the intelligence level of the robot itself.
Computer controller and storage program, which is the brain of the robot system. At present the combination of CPU with memory and I / O can also be done at the level of chip usage, which produces SCM (single chip microcomputer) to distinguish it from microcomputers.
Furthermore, SCM is known as a microcontroller. Some controls are applied that relate to robot control, such as: Open loop control and closed loop control. As for data storage media, usually a microcontroller becomes a storage area either after or before the program is run (depending on the program) then all instructions / commands or programs are stored in the storage media on the microcontroller using EPROM (errassable programmable read only memory).
Robotic System and Development
Several techniques have been developed for programming robots, most notably such as: Walk-through, with a system that uses operators to manually move the robot in accordance with the activities to be carried out, Lead-through, similar to the first method, where the robot is taught movements based on sequence programs actual movement, but this method uses an operator that moves the robot through the control box, keyboard, joystick or digester command, Remote computer link, this method is the most relevant to the CAD-CAM process.
Robot programs can be downloaded from workstations via cable links that are almost the same as the DNC principle (Hawkes. B, 1988).
Some industrial robot developments in ship manufacturing are still adopting robot arm systems that were created for industrial use. Some developments that appear humanoid robot (human-like construction), animalnoid (animal-like construction), but there is no humanoid system that is used to do ship manufacturing. Recently a report released by New Scientist, concerning a study in Daewoo shipbuilding and Marine engineering, regarding the application of clothing equipment for shipyard workers using robotic systems serves to assist shipyard workers to carry out their own transportation on heavy material component parts repeatedly, without feeling the tension of the burden raised, this study was led by Gilwhoan Chu (www.newsscintist.com, techexplore.com, 2014). As shown in Figure 10.
However, this robot mechanism system even though it was created for welding, blasting and painting work especially for closed structures is very ineffective, because the main problems will still exist, namely problems on health, due to direct contact with the work environment. Of course this requires changes in its development so that it is purely a robot doing work inside a closed structure.
Some of these modern robots were developed with a type of humanoid manipulator (humanoid), as developed by a research team from Keiko University, Japan, led by Prof. Sasumu Tachi, by creating TELESAR V Robot Avatar, which was driven by a microcontroller mounted on a part of the human body. This robot moves according to human movement as its operator with several microcontroller and sensor systems that are directly connected to the human body (www.infoniac.com), but it is known that this robot is not for industrial purposes.
Based on the deficiencies that exist, given a concept of future implementation of the form and robot system used for ship manufacturing processes, such as the work of blasting, welding and painting. Namely by applying the concept of a humanoid system, with a control system by humans. As TELESAR V robot avatar has adopted, but the manipulator section below is not yet a mobile platform system.
So the innovation made is a change in the basic manipulator with a mechanical system, resembling the shape of a human foot, but added a vertical hydraulic drive so that it can add the height of the robot to do work on the upper parts with the robot arm’s arms that can be extended.
At the top of the robot there is a sensor / camera that serves to record and detect parts of the work left behind, so that the work gets good results. The camera system is only used to control the work of the robot in a closed room with sensors that detect the results of the work automatically repeating the work if the results have not been included in the standardization of the results inputted in the device on the microchip robot.
To overcome the connecting cable system between the robot and the controller in the operator’s workspace, a remote control system is used as described in the rutarauki blastman with a range of 35 meters (Lee. D al al, 2010).
The working equipment system both welding machine, painting and blasting is a separate part of the proposed robot system, considering the small size of the robot so it does not require installation in a confined space, but instead runs itself into a closed structure, in this case a double-hull structure on ships, with DOF axis on robots by more than 15-axis spin on the manipulator section, which was adopted from TELESAR V robot avatar.
The expectation of the application of this humanoid system is to be able to minimize the impact of the risk of work accidents, with the advantage of a robot that is able to work in full with shapes and equipment that are not complicated to make the movements produced are almost like movements in humans, as an operator in the implementation of work. In general the form of the proposed humanoid plan as shown in Figure 11.
Of course this really requires further research to be able to apply the given humanoid system, both in terms of complexity in programming, to the dynamic power of the robot in operational activities. In addition, it is expected that the application of a humanoid system can be multipurpose so that it is not only used for closed structures, but can also be used in open structures and other work.
This system is only as a basic concept of a humanoid application, which functions to support the manufacturing process in ship building, so there are still many shortcomings that require further study.
From several previous studies that have implemented the use of robotic systems in the shipping industry. However, there are still many shortcomings as a significant obstacle in the process of its work, especially in works carried out in a closed structure.
For this reason, the concept of using a humanoid system that can completely replace human tasks but can still be controlled in the operator’s room, so that not only robots do the work, but human intervention as an operator can control and monitor remotely, as one step of automation of work at the shipyard.
Because this is a basic concept, further research is needed to apply the humanoid system in the ship industry, even for planning and manufacturing the humanoid system itself needs further analysis.
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Source: Maritime Technology Scientific Journal, Wave, UPT Institute for Research and Research on Hydrodynamics Agency for Technology Assessment and Revenue, Volume 9 Number 1 Surabaya July 2015