Sizing electromechanical linear actuators for mobile loader crane
Välimaa, Jussi (2024)
2024
Automaatiotekniikan DI-ohjelma - Master's Programme in Automation Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2024-05-16
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202404173679
https://urn.fi/URN:NBN:fi:tuni-202404173679
Tiivistelmä
The current trend in the working machine industry is to reach the emission regulations that are becoming stricter all the time. The best way to decrease emissions is to make these machines use electricity instead of combustion engines. When going electric, a bonus benefit is also achieved as the efficiency of the original hydraulic system is around 44% whereas the electric actuator can reach an efficiency of 80%. In this thesis, the target working machine is a mobile loader crane and the target of the thesis is to replace the hydraulic cylinders of that crane with electromechanical linear actuators (EMLAs).
As the topic revolves around EMLAs and their components, the different components are show-cased in the thesis. All the different screw options are presented as well, and they are compared with the ball screws that are used in this project.
The main takeaway from changing the cylinders is that now there are no standards that have information on exactly this kind of crane structure. Standards EN SFS 12999 and EN SFS 13000 are made for mobile loader cranes like the one used in this thesis, but the movements of those standards are generated with hydraulics so some other sources are needed as well. For those other sources, a robot standard ISO 9283 with performance testing cycles for industrial robots is used. What makes the crane seem like an industrial robot is the fact that instead of a hook, there is a spherical wrist and a gripper at the end of the crane. This allows the load to be orientated as needed which is not possible with normal crane components.
The main point of this thesis is to size the EMLA components (screw, gearbox, and electric motor) for this case. In this thesis, the equations needed for sizing and the actual calculations are presented. The screw is selected from a BSG zuazo catalog and the electric motor is selected from the Siemens Simotics product family. These components must be selected iteratively with other components in mind. The motor should be as small as possible, and this can be achieved by having the gearbox gear ratio be as big as possible. Increasing the rotational speed can cause issues with the screw and motor so a balance must be found.
As the topic revolves around EMLAs and their components, the different components are show-cased in the thesis. All the different screw options are presented as well, and they are compared with the ball screws that are used in this project.
The main takeaway from changing the cylinders is that now there are no standards that have information on exactly this kind of crane structure. Standards EN SFS 12999 and EN SFS 13000 are made for mobile loader cranes like the one used in this thesis, but the movements of those standards are generated with hydraulics so some other sources are needed as well. For those other sources, a robot standard ISO 9283 with performance testing cycles for industrial robots is used. What makes the crane seem like an industrial robot is the fact that instead of a hook, there is a spherical wrist and a gripper at the end of the crane. This allows the load to be orientated as needed which is not possible with normal crane components.
The main point of this thesis is to size the EMLA components (screw, gearbox, and electric motor) for this case. In this thesis, the equations needed for sizing and the actual calculations are presented. The screw is selected from a BSG zuazo catalog and the electric motor is selected from the Siemens Simotics product family. These components must be selected iteratively with other components in mind. The motor should be as small as possible, and this can be achieved by having the gearbox gear ratio be as big as possible. Increasing the rotational speed can cause issues with the screw and motor so a balance must be found.