Gunnar Bolmsjö - Academia.edu (original) (raw)

Papers by Gunnar Bolmsjö

International Symposium on Robotics, 2018

Friction stir welding (FSW) is a solid state process for joining materials which has demonstrated... more Friction stir welding (FSW) is a solid state process for joining materials which has demonstrated advantages compares with other methods which include joining of mixed materials, hard to weld alloy ...

Advances in intelligent systems and computing, 2016

The ongoing trend towards manufacturing of customized products generates an increased demand on h... more The ongoing trend towards manufacturing of customized products generates an increased demand on highly efficient work methods to manage product variants through flexible automation. Adopting robots for automation is not always feasible in low batch production. However, the combination of humans together with robots performing tasks in collaboration provides a complementary mix of skill and creativity of humans, and precision and strength of robots which support flexible production in small series down to one-off production. Through this, collaboration can be used with implications on reconfiguration and production. In this paper, the focus and study is on designing safety for efficient collaboration operator—robot in selected work task scenarios. The recently published ISO/TS 15066:2016 describing collaboration between operator and robot is in this context an important document for development and implementation of robotic systems designed for collaboration between operator and robot.

Springer eBooks, Oct 2, 2007

A modular and reconfigurable robot which is possible to mount on a nobile base has been designed ... more A modular and reconfigurable robot which is possible to mount on a nobile base has been designed and constructed and is now in the systems in tegration validation phase of the physical robot. During this work, simulations using IGRIP and other related analysis software tools have been important during the development work to analyze and evaluate the design including kinematics,

International Journal of Human Factors in Manufacturing, 1996

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Friction stir welding (FSW) and variants of the process have generated high interest in many indu... more Friction stir welding (FSW) and variants of the process have generated high interest in many industries due to its several advantages such as low distortion, superior mechanical properties over arc ...

Automatic quality monitoring in robotised GMA welding using a repeated sequential probability rat... more Automatic quality monitoring in robotised GMA welding using a repeated sequential probability ratio test method

Flexible human-robot industrial coproduction will be important in many small and middle-sized com... more Flexible human-robot industrial coproduction will be important in many small and middle-sized companies in the future. One of the major challenges in a flexible robot cell is how to transfer information between the human and the robot with help of existing and safety approved equipment. In this paper a case study will be presented where the first half focus on data transfer to the robot communicating the human's position and movements forcing the robot to respond to the triggers. The second half focuses on how to visualize information about the settings and assembly order to the human. The outcome was successful and flexible, efficient coproduction could be achieved but also a number of new challenges were found.

Journal of Manufacturing Technology Management, Apr 1, 2004

Discrete-event simulation (DES) and disturbance reduction techniques are a combination for improv... more Discrete-event simulation (DES) and disturbance reduction techniques are a combination for improving efficiency in manufacturing systems. The DES modelling allows different tests to be carried out by step-by-step alteration. The use of manufacturing improvement techniques should be combined for best results. The changes in disturbances will show us different alternatives in output of the manufacturing system. Two case studies have been drawn up to study the possibilities for disturbance reduction in manufacturing systems by using DES with the proposed method for improved overall manufacturing efficiency. The case studies showed an improvement of output of 14 per cent and 18 per cent, respectively.

Science and Technology of Welding and Joining, Oct 1, 2013

Abstract Previous research within friction stir welding (FSW) has demonstrated that online contro... more Abstract Previous research within friction stir welding (FSW) has demonstrated that online control of welding parameters can improve the mechanical properties and is necessary for certain applications to guarantee a consistent weld quality. One approach to control the process is by adapting the heat input to maintain a stable welding temperature, within the specified operating boundaries. This requires accurate in-process temperature measurements. This paper presents a novel method to measure the temperature at the interface of the FSW tool and workpiece. The method is based on the thermoelectric effect between dissimilar materials. The measurements are compared to thermocouple measurements and to a physical model and show good correspondence to each other. Experiments demonstrate that the method can quickly detect temperature variations, due to geometrical variations of the workpiece or due to parameter changes. This allows use of the method for online control of robotic FSW.

International Journal of Production Economics, Dec 1, 1996

ELSEVIER Int. J. Production Economics 4647 (1996) 459 467 I international journal of product!on e... more ELSEVIER Int. J. Production Economics 4647 (1996) 459 467 I international journal of product!on economics Lifecycle cost analysis of the labor factor Per Dahl6n*, Gunnar S Bolmsj6 Lund Institute of Technology, Department of Production and Materials Engineering, Box ...

The International Journal of Advanced Manufacturing Technology, Jun 9, 2016

The increasing industrial demand for lighter, more complex and multi-material components supports... more The increasing industrial demand for lighter, more complex and multi-material components supports the development of novel joining processes with increased automation and process control. Friction stir welding (FSW) is such a process and has seen a fast development in several industries. This welding technique gives the opportunity of automation and online feedback control, allowing automatic adaptation to environmental and geometrical variations of the component. Weld temperature is related to the weld quality and therefore proposed to be used for feedback control. For this purpose, accurate temperature measurements are required. This paper presents an overview of temperature measurement methods applied to the FSW process. Three methods were evaluated in this work: thermocouples embedded in the tool, thermocouples embedded in the workpiece and the tool-workpiece thermocouple (TWT) method. The results show that TWT is an accurate and fast method suitable for feedback control of FSW.

... removed. The input device to the computer systems was modified from a scanning system to a ma... more ... removed. The input device to the computer systems was modified from a scanning system to a manually controlled system by means of a combined mouth joystick and sip and puff device. ... acceleration. Ms Eva Almberg, a Swedish Manus user ...

International Journal of Machine Tools & Manufacture, Apr 1, 1995

Automation of deburring and cleaning of castings is desirable for many reasons. The major reasons... more Automation of deburring and cleaning of castings is desirable for many reasons. The major reasons are dangerous working conditions, difficulties in finding workers for cleaning sections, and improved profitability. A suitable robot cell capable of using different tools, such as cup grinders, disc grinders and rotary files, is the solution. This robot should be completed with sensors in order to

Advanced Robotics, 1996

A fundamental physical understanding of the properties and structure of dynamic robot models is t... more A fundamental physical understanding of the properties and structure of dynamic robot models is the basis of controller design for robotic manipulators. This paper focuses on the estimation of different parameters which appear in the dynamics models of robots. By introducing candidate functions and a statistical approach to analyze these functions it is possible to identify the significant parameters in

Robotics and Computer-integrated Manufacturing, 1989

A new approach to programming robot systems for arc welding is presented, where the movements are... more A new approach to programming robot systems for arc welding is presented, where the movements are det'med relative to the object and the process. To achieve this, coordinated movements between the robot and the positioner are defined, to give the best welding conditions. By using this technique, a considerable reduction in programming time can be obtained at the robot station. This is of great importance for the use of welding robots in small series production.

Industrial Management and Data Systems, Oct 1, 2001

Focuses on the integrated use of simulation tools, particularly discrete‐event simulation, in the... more Focuses on the integrated use of simulation tools, particularly discrete‐event simulation, in the design and development of manufacturing systems in Japanese industry. The results are based on questionnaires and visits to seven large Japanese manufacturers and show that most of the visited companies do not use simulation to any large extent, particularly not discrete‐event simulation. Some of the reasons for this are general, while others are specific for Japan. However, the use of simulation is believed to increase in Japanese industry. Furthermore, argues that there is a large potential for increased use of advanced simulation techniques in Japanese manufacturing companies, mainly for two reasons. This would result in improved communication, reduced time‐to‐market and higher flexibility in volume and product‐mix.

IOS Press eBooks, Apr 20, 2022

The key driving factors in using humans and robots in collaborative applications for assembly pro... more The key driving factors in using humans and robots in collaborative applications for assembly processes are to reduce assembly time, cost and to improve the human working environment from an ergonomic viewpoint. Currently, there are limited automated procedures in assembly operations in house construction because the traditional type of assembly process depends entirely on manpower. This is common in the assembly process in different industries since assembly is one of the most demanding and intense manufacturing processes, and it is difficult to automate. This paper presents a case study on the implementation of human-robot collaboration for window assembly by way of an offline robot programming simulation. A self-adaptive software architecture that runs on a real-time target machine is also proposed for robotic window assembly. The window assembly method that will be used in this study is called "Click-In" and is manufactured by Fixture System Sweden AB. Apart from robot simulations, detailed suggestions are given for building a pilot cell for robot window assembly. The case study presented in this paper has both economical and ergonomic goals. The economic goal is to reduce the assembly time which will lead to an increase in window production. By introducing human-robot collaboration, operators do not need to perform uncomfortable assembly operations-rather the robot will perform these unergonomic operations. The feasibility of both goals is verified with offline robot programming simulation.