Shintaro Sakamoto

Parallel-link robot for pipe inspection

In air conditioning equipment, it is very important to diagnose in-pipe corrosion for preventing various troubles such as water leakage, deterioration of performance and so on. We have been developing a pipe diagnostic system for decreasing the time and workload of the inspection and improving the accuracy of the diagnosis, especially a pipe thickness measuring robot with ultrasonic probe which can conduct inspections from outside of the pipe. Existing inspection robots using ultrasonic probes are not suitable for measuring the entire surface of pipes because they use rails fixed to the pipe for scanning, or even if they have unfixed rails and can move along the pipe, they cannot measure joints such as elbow. Therefore, we propose a new pipe inspection robot with parallel-link mechanism, which has a circular rail for scanning the ultrasonic probe, a manipulator for setting the rail and a mobile robot for moving along the pipes. The manipulator and the mobile robot are constructed with the parallel-link mechanism. The feature of this robot is that it can pass elbows and so can measure every section of them. In this paper, we describe the robot mechanism and control method, and the results of experiments with the robot.

Laser Marking System Based on 3D CAD Model

In many cases of renovation work, it is very difficult to gain sufficient information about the existing building such as the positions and dimensions of the frame, interior and equipment because of incomplete or missing drawings. As a result, it is necessary to fabricate the parts on the construction site. We have been developing a system for measuring existing buildings precisely using a 3D laser scanner before renovation work, fabricating the parts in factories and assembling them on site. This system will increase productivity and eliminate construction waste. The system requires a function for positioning of the parts and marking precisely on the site. Our developed marking system determines positions from 3D-CAD data and indicates them with a motor-driven Total Station. The position data is produced from objects such as points and lines stored in a design file, and is saved as a marking data file. The Total Station reads the data file and marks the positions by laser automatically and precisely. This report describes the function to produce the position data file and to mark the positions with the Total Station. It also shows the results of a field test at an actual construction site. This research was carried out with a grant from the Ministry of Land, Infrastructure, Transport and Tourism.

Development of UAV Indoor Flight Technology for Building Equipment Works

In the Japanese construction industry, An UAV has begun to be used for outdoor works. On the other hand, most of building equipment works is indoor work, often working in touch with the surrounding environment near the ceiling. Air volume measurement is an example of building equipment works near the ceiling. Conventionally, a worker gets on a temporary scaffold to approach the ceiling at the high position and measures the air volume just under the diffuser installed on the ceiling with using the handy type anemometer. This conventional work has low productivity and high cost for safety management. Furthermore, this tendency is remarkable in rooms with high ceilings such as entrance halls and factories. We propose a new measurement method using the UAV with air volume measuring device, and develop and evaluate the system. The visual feedback control system for self-localization is also developed because the GPS cannot be used indoors. In addition, a high ceiling room with the diffuser is constructed as a mock-up for experiment. We analysed the positioning errors of the UAV when hovering and when approaching and touching the diffuser. Also, we evaluated the touch performance of the UAV to the ceiling by measuring the air volume. As a result, it was found that the UAV can ensure the performance necessary for air volume measurement in this experiment.

A study on measuring of reinforced-concrete structure by 3D laser scanner and making design of pre-cut interior finishing components with polygon model

To achieve renovation work without noise, the authors developed techniques of manufacturing pre-cut interior finishing components for renovation work. In this paper, to achieve the system of pre-cut interior finishing components, the authors describe a measuring method of reinforced-concrete structure by 3D laser scanner and then describe a method of making a design of pre-cut interior finishing components with the polygon model. Using these two methods, the steps of manufacturing pre-cut interior finishing components consist of the following four steps: First, measure the building shape using a 3D laser scanner. Secondly, integrate a point cloud data and retrieve the markings on the floor. Then, create a polygon model of the building based on the point cloud data. Lastly, make a drywall design using a polygon model. To evaluate the technique feasibility of manufacturing pre-cut interior finishing components, the authors have conducted an experiment of the finishing interior work of the drywall. Using pre-cut interior finishing components, the authors have been able to achieve interior finishing work without noise.

3D Measuring and Marking System for Building Equipment: Developing and Evaluating Prototypes

The measuring work has been done manually with the scales in the construction of building equipments. We have been studying a 3D measuring and marking system using a total station to increase accuracy and decrease workload. One feature is the pointing device for measuring indirectly the hidden areas which cannot be measured with a stand-alone total station. The device has a sensor which consists of a pinhole and a position sensitive detector for measuring the incident angles of the received laser and it’s possible to calculate the pointing position by using the data. The other is the positioning device for marking accurately relative to the points which the total station indicates with the laser automatically. The displacement from the target position is calculated from the device position and the operator marks with the marking position adjusting function of the device. This paper describes the system configuration, measuring and marking theory of the system with those devices, and the results of evaluation experiments with prototypes.

Development of an Air Volume Measuring Instrument: WINSPEC

Prior to completion, the various facilities associated with a building undergo performance testing. For air conditioning facilities, it is necessary to confirm that each apparatus meets the design values for air supply and emission volume. In keeping, rather than a fully automated robot, we developed a human-operated instrument that enables ceiling outlets to be reached without using a stepladder; we also engaged in development to make it possible for the instrument to move smoothly around worksites. This instrument has been used in actual completion inspections, and results have been obtained for dozens of properties to the present. Although WINSPEC has primarily contributed to lowering costs through reduced labor power and shortened work time, it is also used for the purpose of guaranteeing measurement accuracy. This report provides an overview of WINSPEC and presents how the instrument has been evaluated from results of actual use at construction sites.

Study on In-Pipe Corrosion Diagnosis System (Inference of Corrosions Using Wavelets and Two Dimentional Data)

In non-destructive inspection, it is very important to know in-pipe corrosions form because its information is available to infer kind of corrosions and cause of corrosions. An ultrasonic flaw detection method is often used for because of easy operation. However measurement accuracy is not good. Especially it is very difficult to get accurate thickness information at complex corrosions area where there are multiple corrosions. In this paper, we proposed the algorithm to improve a measurement precision of ultrasonic flaw detection method by measuring multipoints data and frequency characteristics of ultrasonic wave signals. The wavelet analysis of ultrasonic echo is used in order to detect candidates of reflect wave from a crrosion. We applied the algorithm to a pipe with the natural corrosions which have complex form and showed the utility compared to thickness measurement method.

Determining Internal Local Corrosion of Screwed Pipes Through Ultrasonic Testing

In diagnosing air-conditioning pipe deterioration, it is especially important to inspect screwed parts because their original thickness is thinner than that of straight parts and it is comparatively easy for leakage to occur if there is local internal corrosion. Usually, a radiographic test is used, but this method requires a licensed person to carry out the inspection. We examined a method of applying an ultrasonic test for the inspection, and proposed a method for detecting internal local corrosions of screwed parts and estimating the size of corrosion with surface SH waves. In this paper, we propose a method for detecting internal local corrosion of screwed parts of air-conditioning pipes with ultrasonic testing. The objective of the first step is to detect artificial corrosion and estimate its size and position. It is impossible to detect corrosion with a normal probe because a joint or valve overlapping the screwed pipe prevents ultrasonic waves from reaching the inside. Therefore, we used an angle probe, specifically a surface SH wave angle probe, because the thickness of the pipes requires a large angle of incidence, close to a right angle. We describe the following in this paper: ・ The results of experimental analysis on the echo from screwed parts of pipes. ・ The method used to detect local corrosion and estimate the size and position by using the pipe-end echo. ・ The results of tests on artificial corrosion pipes and the limitations of this method.

Global Matching for Air Conditioning Inspection Robot

This paper proposes the navigation system of autonomous mobile robot. The conventional robot was moved in the navigation method based on the landmark recognition. But, the landmark was often lost sight of, as the result the robots self-position was lost. The authors propose the method that the error that was occurred by the robot is recovered. The method can decide the self-position by using the information on the corner, windows and doors of the room.