Safety of Zonal Hydraulics in non-road mobile machinery
Eloranta, Vili (2020)
2020
Sähkötekniikan DI-tutkinto-ohjelma - Degree Programme in Electrical Engineering, MSc (Tech)
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
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Hyväksymispäivämäärä
2020-07-30
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202006246221
https://urn.fi/URN:NBN:fi:tuni-202006246221
Tiivistelmä
As governments from multiple nations encourage novel and inherently emission free power trains to be commissioned, multiple machinery manufacturers are developing their own solutions in response. This thesis focuses on one of the solutions, a Zonal Hydraulics concept that is a combination of electrohydrostatic actuators implemented in non-road mobile machines.
When the new novel systems are introduced to market the safety must be ensured. Currently standards mainly cover the conventional mobile machines with 12 – 24 VDC systems, and therefore they are not up to date for the ZH designed for higher voltages.
The system design for NRMM, which has replaced the conventional hydraulics with Zonal Hydraulics concept, includes direct electric motor control that has expected voltage levels of 700 – 800 VDC and hydraulic actuators. Currently this type of complete system is not covered in a single standard and requires designers to investigate from multiple sources. In this thesis, a review of the current safety standards from multiple fields was realized to gain knowledge on possible future requirements.
This thesis includes a hazard analysis for an electrified micro-excavator case that has Zonal Hydraulics system implemented to replace the conventional hydraulic ones. The hazard analysis was performed by using the Japanese digging cycle (JCMA07) in a tight operational environment to increase possible hazards when using the novel hydraulic system. The hazard analysis was done based on ISO 19014, and the gained performance level requirements were later used in the safety system design.
The safety system design was proposed following the requirements found in standards and based on the performance level attained from the hazard analysis. The safety system was designed to be redundant for high reliability. The system was composed from two control units that each had their corresponding electric and hydraulic safety actuators.
When the new novel systems are introduced to market the safety must be ensured. Currently standards mainly cover the conventional mobile machines with 12 – 24 VDC systems, and therefore they are not up to date for the ZH designed for higher voltages.
The system design for NRMM, which has replaced the conventional hydraulics with Zonal Hydraulics concept, includes direct electric motor control that has expected voltage levels of 700 – 800 VDC and hydraulic actuators. Currently this type of complete system is not covered in a single standard and requires designers to investigate from multiple sources. In this thesis, a review of the current safety standards from multiple fields was realized to gain knowledge on possible future requirements.
This thesis includes a hazard analysis for an electrified micro-excavator case that has Zonal Hydraulics system implemented to replace the conventional hydraulic ones. The hazard analysis was performed by using the Japanese digging cycle (JCMA07) in a tight operational environment to increase possible hazards when using the novel hydraulic system. The hazard analysis was done based on ISO 19014, and the gained performance level requirements were later used in the safety system design.
The safety system design was proposed following the requirements found in standards and based on the performance level attained from the hazard analysis. The safety system was designed to be redundant for high reliability. The system was composed from two control units that each had their corresponding electric and hydraulic safety actuators.