| 1. |
- Axin, Mikael, 1984-, et al.
(författare)
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Energy Efficient Fluid Power System for Mobile Machines with Open-centre Characteristics
- 2014
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Ingår i: 9th JFPS International Symposium on Fluid Power. Matsue, Japan, 28-31 October 2014. - : The Japan Fluid Power System Society. - 4931070108 ; , s. 452-459
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a flexible and energy efficient system solution which mimics the behaviour of an open-centre system. An electro-hydraulic variable displacement pump and closed-centre valves are used. Instead of having a flow in the open-centre gallery, that flow is calculated using a pressure sensor and a valve model. The variable pump is then controlled in order to only deliver the flow that would go to the actual loads. It is also possible for the operator to decide how much load dependency there should be. The extreme case is not having any load dependency at all, resulting in a system where the pump displacement setting is controlled according to the sum of all requested load flows. It is thus possible to realize a system design with open-centre characteristics, a flow control system or something in between. Each operator can thereby get their optimal control characteristic while having high energy efficiency.
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| 2. |
- Dell'Amico, Alessandro, et al.
(författare)
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Closed-Centre Hydraulic Power Steering by Direct Pressure Control
- 2014
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Ingår i: The 9th JFPS International Symposium on Fluid Power : Matsue 2014 : Oct. 28-31, 2014. - : The Japan Fluid Power System Society. - 4931070108 ; , s. 332-339
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An ongoing trend in the vehicle industry is the development of steering related active safety functions for increased road safety. For this to be a reality there must exist a steering system that allows to either change the road wheel angle or torque by means of an external signal, called active steering. Due to heavy vehicles’ high axle load, hydraulic power is needed to assist the driver in turning the wheels. This paper looks into a solution where self-regulated pressure control valves are used for electronic control of the assistance pressure in order to realise active steering. The valve has closed-centre for a high potential to reduce the energy consumption. A model based approach is used to analyse the system. A non-linear simulation environment is developed to compare the closed-centre system with the original system. A linear analysis is also performed to discover the influence of valve properties on steering system performance. Results have shown that a feasible solution exists and that there exists a relation between valve dynamics, boost gain and steering system loop stability.
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| 3. |
- Pettersson, Karl, 1983-, et al.
(författare)
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Simulation Aided Design and Testing of Hydromechanical Transmissions
- 2014
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Ingår i: The 9th JFPS International Symposium on Fluid Power, Matsue, 2014. - 4931070108
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Konferensbidrag (refereegranskat)abstract
- This paper demonstrates the use of high-speed simulation in transmission conceptual design and presents a transmission test bed for hardware-in-the-loop simulations of hydromechanical transmission concepts. Complex transmissions, such as multiple-mode hydromechanical transmissions and hydraulic hybrid transmissions, present new difficulties and costs in the development process. There is today a greater demand for more efficient product development and more work has shifted towards simulation. The Hopsan simulation package allows robust, high-speed simulations suitable for both offline and hardware-in-the-loop simulation. New simulation models for hydromechanical transmissions are developed and used to simulate a known two-mode transmission concept. The same concept is also tested in hardware-in-the-loop simulations in the proposed transmission test bed. Results show good agreement with the hardware tests and highlight the proficiency of the simulation tools.
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