Examples of Unique Solutions
Below, examples are given of solutions created at Flumes which are unique in some sense and which our present research is based on.
The Valvistor Valve
Conventional pilot operated two-way cartridge valves has the shortcoming that, for flow control, the conventional valve element can only be fully open or fully closed. The unique Valvistor valve invented at Flumes can do that, i.e. proportional flow control as well as pressure control.
Control of Hydraulics with Complex Loads
A thorough PhD dissertation from Flumes in this area has been used for most follow up research on stable and damped control of load-sensing hydraulics in combination with oscillating mechanical structures such as cranes. The theory was the base for a recent student project at Flumes for active damping of a crane using commercial proportional CAN-based valves.
The flow ripple of piston pumps causes noise. In order to design silent pumps, measurement techniques are needed to measure the flow ripple. The high-frequency flow cannot be measured directly, but through pressure sensors. Flumes has developed a technique that has been used up to 8 kHz.
The Delay Line Method
Hydraulics is demanding to design and control so simulation is a necessary tool. Flumes has applied and refined a simulation technique where the time needed for information propagation in nature is exploited. The technique yields very fast simulations and is presently used in the Hopsan tool for hydraulics and at SKF for bearing simulation. It has also been applied in coupled simulation among several simulation environments for wheel loader analysis and design.
Hopsan Simulation Tool
This free simulation tool for hydraulics, developed by Flumes, is central for the rock drill design at Atlas Copco Rock Drills and for pump design at Parker Hannifin. The tool makes use of delay lines to capture wave propagation phenomena and to gain fast simulation.
The flow pulsations from piston pumps give rise to noise and fatique. With a small volume in the pump, the noise is drastically reduced. Flumes developed the solution through extensive simulations and use of the two-microphone method.
A hydrostatic transmission with one pump and motor can not be used on large machines. With two motors, working range is expanded. The difficulty lies in connecting the second motor when it is needed. Flumes has implemented a working prototype including controller using hardware-in-the-loop simulation.
Flumes has developed algorithms for assisting in parking along the road. Cheap ultra-sonic sensors are utilized by a computer for guiding the driver into the parking space through animations on a screen.
Simulation speeds up the design process since it replaces a part of the expensive and time consuming physical experiments. HWIL has a place between simulation and experiments, where one part of the system is simulated and the rest is run for real. Flumes has developed HWIL solutions for several different applications as shown.
Last updated: Mon Jul 11 09:19:09 CEST 2016