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- Högström, Tomas, et al.
(författare)
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Telecommands for Remotely Operated Vehicles
- 1995
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Ingår i: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080423663 ; 28:11, s. 301-306
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Tidskriftsartikel (refereegranskat)abstract
- The problem addressed is controlling a robot over a communication channel with low bandwidth, a non-neglectable time delay and time jitters. The external sensors on the robot are a time-of-flight range measuring laser and a video camera. Video images are used by the operator for interpreting the scene and are only sent at “fax rate”. The operator is thus interpreting the workspace around the vehicle, making plans for the individual operations in a composite task and is giving high level commands. The telecommands are to be executed autonomously by the robot. Inside the robot the control loop is closed with full bandwidth when each command is executed.This paper reports on work in progress and focus on:1. Incremental map building, especially simplifications for large buildings and robustness when the vehicle returns to a previously mapped area. This is a very useful support function for the operator.2. Tests of telecommands on a mobile robot available for experiments over the Internet. Available sensors are inclinometers, odometry, CCD intensity images and range measuring laser data.Other needed telecommands studied previously are:Travelling along corridors, follow walls etc. The operation is based on the range weighted Hough transform and is both robust and precise. The repeatability is about 1 cm at 1 m/s. The robot is not disturbed by people passing in the corridor.Commands for passage through an open door works within 1 cm and 0.5 degrees at a speed of 0.5 m/s. Passing between irregular obstacles is less accurate.Using rate gyros, lock the heading of the robot when driving on a straight line. Also preprogrammed 90- and 180-degrees turns.Automatically enter a camera defined line. The direction of the camera can be used to drop a new coordinate frame at any time (using a button on the keyboard). The robot will automatically enter this new line and also compensate for the overshoot.To integrate these different commands into a complete system is a resource demanding task for the future.
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| 3. |
- Nygårds, Thomas, 1980, et al.
(författare)
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Vibration Control of Washing Machine with Magnetorheological Dampers
- 2006
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Ingår i: Proc. The 8th International Conference on Motion and Vibration Control (MOVIC 2006), August 27-30, 2006, KAIST, Daejeon, Korea. ; , s. 480-485
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Konferensbidrag (refereegranskat)abstract
- The manufacturing of washing machines has lately been an important issue for the appliance industry. Current environmental awareness demands the improvement of machine efficiency and increasing of quality of washing processes. Developing of high efficient and high speed spinning washing machines raises the problem of designing smart suspension systems to control vibration and noise in real time. In the paper a horizontal-axis washing machine is under the study. The machine has a drum with perforated walls. In the water extraction process, the drum starts rotation and this gives rise to significant centrifugal imbalance forces and imbalanced rotation of the laundry mass. This results in vibration and shaking. By elimination of such vibrations it will be possible to design more silent washing machines for higher wash loads within the same outside dimensions. In the paper the results of modelling of dynamics of washing machine and designing of smart suspension system comprising magnetoreological dampers for semi-active vibration control are presented. The commercial software MSC.ADAMS/View and MATLAB/Simulink have been used for 3D-modelling of dynamics of washing machine. Both traditional suspension with passive dampers and suspension with magnetoreological dampers are implemented into the developing mathematical models. Identification of passive dampers and magnetoreological dampers dynamics was done based on experimental study. Full scale test rig of washing machine was used for validating the models. The validated model has been used for designing and optimization of smart suspension system with magnetoreological dampers of high speed spinning washing machines. Analysis of the obtained results has proved a big potential of utilization of magnetoreological dampers for developing of semi-active suspension systems for washing machines.
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| 4. |
- Tryding, Johan, et al.
(författare)
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Experimental and theoretical analysis of in-plane cohesive testing of paperboard
- 2017
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Ingår i: International journal of damage mechanics. - : SAGE Publications. - 1056-7895 .- 1530-7921. ; 26:6, s. 895-918
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Tidskriftsartikel (refereegranskat)abstract
- In-plane cohesive failure of paperboard was characterized by short-span uniaxial tension tests. Six paperboards’ qualities were experimentally investigated, from which cohesive stress-widening curves were extracted. A fracture energy was defined, expressed in the tensile strength and maximum slope of the cohesive stress-widening relation. Analytical cohesive relations were derived based on the tensile strength and maximum slope, utilizing the Morse potential for diatomic molecules. It was experimentally found that the maximum slope and fracture energy depend on the tensile strength. The ratio of the maximum slope to the elastic modulus (stable length) was shown to be independent of the tensile strength.
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