Opettajan muuttuvat roolit – yhdessä yhteisölliseen opetuksen kehittämiseen

Opettajan muuttuvat roolit - yhdessä yhteisölliseen opetuksen kehittämiseen on julkaisu, joka kuvaa Aalto-yliopiston yliopistopedagogiselle kurssille osallistuneiden kehittymistä ja kehittämiskohteita vuoden 2012 aikana. Vuoden mittaisen prosessin aikana yksittäisistä opettajista ja tutkijoista tuli opetusta ja oppimista kehittävä ryhmä. Osallistujista kasvoi tutkijoita, jotka haluavat opettaa ja opettajia, jotka haluavat tutkivalla otteella kehittää opetusta. Julkaisussa Opettaja kehittäjänä -kurssin osallistujat kuvaavat kehittämishankkeitaan. Lisäksi kurssin suunnittelijat ja ohjaajat jäsentävät kurssin ensimmäistä toteutusta ja sen onnistumista. Mitä opittiin, kun kurssin sisällön tuottivat osallistujat ja ohjaajat yhdessä? Julkaisu tarjoaa näkökulmia opetuksen kehittämiseen ja tutustuttaa lukijan Aalto-yliopiston asiantuntijoiden opetustyön arkeen. Teos sopii kaikille yliopisto-opetuksesta kiinnostuneille

Effect of Operating Parameters on Efficiency of Swash-Plate Type Axial Piston Pump

Funding Information: Funding: This research has received funding from Business Finland (Finnish Funding Agency for Innovation), project GOOD [Future electrified mobile machinery for harsh conditions] and School of Engineering, Aalto University, Finland. Publisher Copyright: © 2022 by the author. Licensee MDPI, Basel, Switzerland.In an effort to improve the energy economics of hydraulic systems, attention should be paid to reducing power losses in two main entities, energy converting components, and energy controlling and conveying components. Achieving the former requires utilizing components’ most energy efficient operating range. The energy converting efficiency of a pump, which is the primary energy converter in a hydraulic system, is determined by several operational factors. Of these, only pressure and rotational speed are normally considered, but also the fluid temperature and derived capacity with variable displacement pumps have a major effect on the efficiency. Omitting these factors may lead to running the pump outside its most efficient operation range and cause high energy losses. Operating the pump in its optimal region calls, however, for detailed knowledge of its performance characteristics, which are not generally made public by the pump manufacturers. This study presents the performance measurement results of a variable displacement axial piston pump in the form of efficiencies as a function of pressure, rotational speed, derived capacity and inlet fluid temperature. The results show that all of these factors have a significant impact on pump’s energy conversion efficiency and should, therefore, be taken into account when operating a hydraulic pump.Peer reviewe

Experimental Study on Fast and Energy-Efficient Direct Driven Hydraulic Actuator Unit

In this experimental study, a Direct Driven Hydraulics (DDH) system of the closed circuit type was utilized for cyclic vertical actuation in heavy load material handling. The actuator was controlled by a speed-controlled fixed displacement pump. The high energy saving potential of this system has been demonstrated in previous studies by the authors, but the dynamic characteristics of the ramped and P-controlled base system were considered unsatisfactory. Therefore, the system was implemented with an open-loop S-curve control that utilized a pre-calculated RPM (revolutions per minute) profile for the electric motor in order to realize a smooth actuator and load transition as a function of time. The results indicate that S-curve control is exceptionally well suited for producing a controlled lifting–lowering rapid motion with a heavy load, while still keeping the actuator chamber pressures within acceptable limits. In comparison, the motion produced by P-control was characterized by large unwanted pressure peaks together with velocity fluctuations and vibrations at the end of the stroke. Using a combination of S-curve control and hydraulic load compensation, a mass of 1325 kg could be moved 0.26 m in less than 0.5 s. The load compensation reduced the energy consumption by 64%, which would allow downsizing the electric motor and enable cost-efficient DDH implementation