Master of Science in Mechanical Engineering
http://dl.lib.uom.lk/handle/123/744
2024-03-28T13:41:55ZCritical evaluation of container trailer failures and improvements in their manufacture
http://dl.lib.uom.lk/handle/123/10397
Critical evaluation of container trailer failures and improvements in their manufacture
Mugunthan, S
Container trailer manufacturing is a growing industry in Sri Lanka. Only two organizations are involved in this business and the monthly production was recorded as 100 to 125 trailers. Like other manufacturing industries, trailer industry also faces problems due to trailer failures and difficulties to improve the trade. Failures are mainly due to lack of design stage analysis of the product. The primary objective of my research project is to analyze trailer failure problems and suggest solutions to improve the trailer industry in Sri Lanka. The methodology of this research is a combination of research training programme, questionnaire based study and a finite element analysis of the trailer solid model. Research training programme was arranged in a leading manufacturing and servicing organization in Sri Lanka by the Department of Mechanical Engineering, University of Moratuwa. It was very useful to understand the trailer manufacturing concepts, designs, trailer failures and the general problems faced by the trailer industry. Questionnaires are produced to two different categories of industries such as Trailer manufacturers and Trailer users. Questionnaires for trailer manufacturers are oriented towards identifying the techniques used by manufacturers to control the failures especially in design stage and identifying their problems and limitations in manufacturing trailers. Questionnaires for trailer users are oriented towards identifying trailer failures. A finite element analysis was carried out to study the present design of a particular type of trailer to identify the efficiency in design and to present any solutions if needed. Further, there were several rounds of semi-structured interviews with technical specialists, designers, supervisors and welders who were involved in trailer manufacturing. By the combination of all the efforts, it is found that trailer failures are mainly due to the problems due to design, fabrication, materials and parts selection, human resource and trailer misuse. Suggestions to present trailer problems and future improvements in trailer manufacture are produced.
2014-08-06T00:00:00ZSensor fusion model for low cost mobile robot platform
http://dl.lib.uom.lk/handle/123/10304
Sensor fusion model for low cost mobile robot platform
Pallegedara, A
This project investigates the general robots behavior, control and Multi-Sensor sensory fusion techniques using low cost Infra-red (1R) sensors, Sonar sensors (Ultrasonic sensors), Optical encoders and general-purpose Web camera specially CMUcam CMOS camera. According to my literature survey 1 have found that current high - tech researches are going on by applying very expensive and sophisticated sensory devices such as, Stereo-Vision sensors, Laser scanners, High resolution CCD camera etc. along with embedded high speed Digital Signal Processor (DSP) systems. Due to above technical and financial restrictions facing with research as well as depth of expected research study to be performed; very complex and highly expensive components should have been eliminated and would not be illustrated further. This project particularly based on sensory fusion with image processing techniques. The objective as well as motivation is, to build a low cost, optimal level resource consuming reliable sensory system for a robot. Relying only one sensor especially the time - of flight sensor (sonar) will probably cause problems such as, sonar sensors are limited in resolution, range and the size of the object they can detect, sensor value (from sonar) may not correspond to the actual distance of the object, cross talk, fore shorting and specula reflection. Sensors sometimes can be complementary or redundant since it is necessary to make an appropriate selection of sensors when building the sensor suit for a mobile robot. For an example, Infra-Red (IR) can provide less-accurate range measurements compared to the ultrasonic sensors but IR sensors can provide a large number of measurements in a short time period; can easily be mounted on a scanner to provide panoramic view and sonar sensors are excellent for mobile robot applications when especially navigate through a room filled with obstacles. In many cases multiple sensor sources are better than single sensor reading. This led to the development of the sensor system architecture with sensory fusion techniques. Further, this permits more than one sensor making the sensory system more reliable and robust. Typically the general architecture of the fusion sensor has been categorized into two; low-level fusion and high-level fusion. In this project, the architecture is developed based on actionoriented sensory fusion, in belief that multiple sensor reading can be fused and would give rise to certain behavior for mobile robot. And also Filtering techniques are employed to reduce the uncertainties in the line segment representation and Data / Image fusion. Some of the issues in designing particular vision system for the robot, involves capturing and storing the entire image before starting the image analysis and to overcome some of general vision system issues, system has to be designed to extract visual information from the environment in Real-Time using an affordable 'off - the - shell' digital CMU cam color camera and embedded controller. The final implementation and results were obtained by using Simrobot simulations and real low cost mobile platform was developed to certify the trialed simulations and implemented behaviors. It is discussed that complex situations such as emergency behavioral decision making, significantly deviates from expected once so that vision and image processing in real time make hardcore experience in low cost camera 1 had used and also uncertainty of sensor inputs truly make unexpected fusion results with noise addition as well
2014-07-24T00:00:00Z