Improvement of a Friction Test Machine
Sälemaa, Sauli (2019)
2019
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2019112723046
https://urn.fi/URN:NBN:fi:amk-2019112723046
Tiivistelmä
This thesis deals with the improvement of a friction test machine which has been designed by Rejlers Finland Oy. The machine has been built and during its testing, lack of compliance between the drives and the mechanisms, as well as the cumulative deflection caused by the lack of rigidity have caused the machine to be redesigned. The screw jack system was not compliant with the PID controller because the screw jack is irreversible, i.e. after the actuation force has been removed, the forces will not return without actuation to the original state. In consequence, the PID controller could not control the current of the servomotor, thus causing excessive forces during its operation and caused the rotary specimen to cut the plane.
The primary objective of the thesis was to modify the screw jack system to be compliant with the internal PID controller. The secondary objective was to redesign the construction of the linear actuator carriage, and make it as stiff as possible within the constraints set by the original design.
The designing of the assembly was carried out with SolidWorks 2018 software where the first friction test machine was already designed in CAD. The simulations were performed first with SolidWorks Simulation software, but after significant time consumption between the iterations, the simulations were conducted with Ansys Mechanical widely used in the mechanical finite element analysis.
The modifications to the actuator mechanism assumed to be compliant with the PID controller. The simulations’ results compared to the original design, had significant improvements in the stiffness of the system, without compromising the structural integrity or fatigue life of the machine. The project will be continued by the commissioning of the friction test machine prior to the delivery to the clients.
The primary objective of the thesis was to modify the screw jack system to be compliant with the internal PID controller. The secondary objective was to redesign the construction of the linear actuator carriage, and make it as stiff as possible within the constraints set by the original design.
The designing of the assembly was carried out with SolidWorks 2018 software where the first friction test machine was already designed in CAD. The simulations were performed first with SolidWorks Simulation software, but after significant time consumption between the iterations, the simulations were conducted with Ansys Mechanical widely used in the mechanical finite element analysis.
The modifications to the actuator mechanism assumed to be compliant with the PID controller. The simulations’ results compared to the original design, had significant improvements in the stiffness of the system, without compromising the structural integrity or fatigue life of the machine. The project will be continued by the commissioning of the friction test machine prior to the delivery to the clients.