Diss. Linköping : Linköpings universitet, 2007.

Diss. (sammanfattning) Linköping : Univ., 2002. / Härtill 6 uppsatser.

Diss. Linköping : Univ., 2000.

Diss. Linköping : Linköpings universitet, 2008.

<p>As a part of ongoing research projects at University West in the area of robot welding applications, a study was looked-for in the field of feedback control of robot systems with external sensors. A literature survey was performed in this field. A virtual instrument was developed in a PC using the LabView software from National Instruments. The instrument receives a signal from a force sensor, converts the input data and sends out the computed signal on a configured serial port. This information is then received by the robot system to be used to control the robot trajectory. The system was tested and it showed that external closed loop control of robot movement was possible to do. Problems with high delay time in the ABB IRB2400 robot system limits the bandwidth or the speed of the closed loop system. This delay time is caused by the intrinsic offset function that is needed to change robot path during motion. This function requires a great computational cost. The conclusion is that ABB IRB2400 robots, with the S4 controller, are limited for applications with low bandwidth because of their motion computation program structure. It does not allow for external feedback applications that require higher robot movement speeds.</p>

As a part of ongoing research projects at University West in the area of robot welding applications, a study was looked-for in the field of feedback control of robot systems with external sensors. A literature survey was performed in this field. A virtual instrument was developed in a PC using the LabView software from National Instruments. The instrument receives a signal from a force sensor, converts the input data and sends out the computed signal on a configured serial port. This information is then received by the robot system to be used to control the robot trajectory. The system was tested and it showed that external closed loop control of robot movement was possible to do. Problems with high delay time in the ABB IRB2400 robot system limits the bandwidth or the speed of the closed loop system. This delay time is caused by the intrinsic offset function that is needed to change robot path during motion. This function requires a great computational cost. The conclusion is that ABB IRB2400 robots, with the S4 controller, are limited for applications with low bandwidth because of their motion computation program structure. It does not allow for external feedback applications that require higher robot movement speeds.

<p>This thesis work was done together with SAAB Automobile (Saab) and has investigated how to implement vision based robot systems into Saab's body shop part of the factory (where the car body is mounted together). Vision based robot systems are common in the automotive industry, but not so much in the body shop part of the factory. This thesis work was a continuation of a project where the basics about a camera, Cognex In-Sight 5100, were learned. This camera is a so called smart camera, which means that it can work alone without a computer controlling it. This because it has a small processor built in to the system. The thesis work was solved by looking at an area of an object and compare differences in this area when moving the object. With these differences the accuracy of the camera could be known. The optics, lighting and calibrations were also investigated to learn how to use them best. The work was also to be a part in a team that investigated how to best implement vision based robot systems into Saab's body shop factory. It was members from Saab's factory, professional vision companies and a company that was professionals in the making of jigs and other mechanical inventions. The results from the tests that were made showed that it was important to calibrate the camera right. For example one test was to see how accurate the camera was to guide a gripper to the middle of a beam when having the field of view at the side of the beam. The tests showed that the camera showed wrong in both translation and angle. If both errors were superposed calculated together big errors could occur. The results also showed that this camera system is not advanced enough to handle all different situations that need to be solved in the body shop factory. For example the camera can not take two pictures and then compare them. These functions can be programmed in a PC based vision system where the programmer can program whatever he wants. It is no limitations. The camera that was investigated is best used when it is not too complex solutions. For example it can guide the robot where the accuracy does not need to be very exact.</p>

<p>This report describes a Bachelor thesis work in which a robotised laser welding cell has been modelled and simulated for the purpose of making a presentation movie. The report shows that the work has been concentrated on making the movie from the modelling phase through the recording of the movie and ending up with the editing of the final presentation movie. A pre-study was made prior the Bachelor thesis work. In the pre-study a literature study was conducted about measurement and calibration of a welding cell. Measurement of almost all equipment in the entire cell was also conducted in the pre-study. The main result of this pre-study is a thorough investigation of what objects and functions that needs to be modelled in order to explain the functions in the specific laser welding cell The purpose for this Bachelor thesis work is to give an efficient and alternative way to present a laser welding cell that resides in Production Technology Centre (PTC) at Innovatum, Trollhättan Sweden. The movie can be used outside PTC or if the laser welding cell is occupied with work, since it is not allowed to be inside the cell when in progress. The result of this work is a nearly 12 minute long presentation movie which shows all predefined elements of the cell together with a real welding sequence with metal deposition (MD).</p>

This report describes a Bachelor thesis work in which a robotised laser welding cell has been modelled and simulated for the purpose of making a presentation movie. The report shows that the work has been concentrated on making the movie from the modelling phase through the recording of the movie and ending up with the editing of the final presentation movie. A pre-study was made prior the Bachelor thesis work. In the pre-study a literature study was conducted about measurement and calibration of a welding cell. Measurement of almost all equipment in the entire cell was also conducted in the pre-study. The main result of this pre-study is a thorough investigation of what objects and functions that needs to be modelled in order to explain the functions in the specific laser welding cell The purpose for this Bachelor thesis work is to give an efficient and alternative way to present a laser welding cell that resides in Production Technology Centre (PTC) at Innovatum, Trollhättan Sweden. The movie can be used outside PTC or if the laser welding cell is occupied with work, since it is not allowed to be inside the cell when in progress. The result of this work is a nearly 12 minute long presentation movie which shows all predefined elements of the cell together with a real welding sequence with metal deposition (MD).

This thesis work was done together with SAAB Automobile (Saab) and has investigated how to implement vision based robot systems into Saab's body shop part of the factory (where the car body is mounted together). Vision based robot systems are common in the automotive industry, but not so much in the body shop part of the factory. This thesis work was a continuation of a project where the basics about a camera, Cognex In-Sight 5100, were learned. This camera is a so called smart camera, which means that it can work alone without a computer controlling it. This because it has a small processor built in to the system. The thesis work was solved by looking at an area of an object and compare differences in this area when moving the object. With these differences the accuracy of the camera could be known. The optics, lighting and calibrations were also investigated to learn how to use them best. The work was also to be a part in a team that investigated how to best implement vision based robot systems into Saab's body shop factory. It was members from Saab's factory, professional vision companies and a company that was professionals in the making of jigs and other mechanical inventions. The results from the tests that were made showed that it was important to calibrate the camera right. For example one test was to see how accurate the camera was to guide a gripper to the middle of a beam when having the field of view at the side of the beam. The tests showed that the camera showed wrong in both translation and angle. If both errors were superposed calculated together big errors could occur. The results also showed that this camera system is not advanced enough to handle all different situations that need to be solved in the body shop factory. For example the camera can not take two pictures and then compare them. These functions can be programmed in a PC based vision system where the programmer can program whatever he wants. It is no limitations. The camera that was investigated is best used when it is not too complex solutions. For example it can guide the robot where the accuracy does not need to be very exact.