This paper presents an experimentally validated semi-empirical lumped parameter model developed for analysing the dynamic stability and performance limitations of a pressure compensated vane pump system. The model calculates continuous displacement chamber pressure profiles for the determination of the internal forces acting on the vane pump’s pivoting cam. Extensive measurements conducted on a custom test stand were used to define a nonlinearly progressive bias spring model and a transfer function model of the pump control system valves for realistic system characteristics. Analysis of the complete model reveals the performance limitations imposed by the control system valves in terms of system stability and achievable controller bandwidth are the most restrictive.

Regarding the trend of optimizing energy efficiency and meeting upcoming regulations of energy consumption
there are many ways to refine existing hydraulic drive systems. To gain more knowledge about components,
combinations of those components and their interaction with the overall process, a combination of measurement,
simulation and calculation of energy consumption is used to build the foundation for finding optimization
approaches regarding the efficiency of electro-hydraulic pump drives. This is a three-step process focusing on
the following topics: increased component efficiency, matching pump drive components and adjusted process
layouts. By utilizing this strategy, a manufacturer- and customer-dedicated optimization of pump drive systems
can be realized.

This contribution presents a holistic approach to the system optimization of a highly dynamic proportional valve. The model with lumped parameters which is used for the evaluation of the closed-loop performance is parameterized based on Finite-Element-Method (FEM) data. In addition to the calculation of static characteristic curves, a suitable excitation signal is applied to the transient FEM simulation. The valve dynamics of the current geometrical valve design are identified using the transient simulation results. This new approach enables a fully automated system optimization of a proportional valve. Hence, during the optimization, human expertise is not required.

The paper presents the Dana methodology to address the integrated design for winch systems. Beginning with
the analysis of the generic expected performance of the system, the main issues and tasks are evaluated;
moreover, the design workflow and the main benefits of integrated design are described with particular attention
to the strong team working required to fulfil the defined target in the most efficient way.
Different sub-systems are analysed: the hydraulic motor-winch coupling, with particular attention to clocking
speed and its relationship with motor non-uniformity grade and specific reducing gear-ratio to improve
hydraulic-mechanic coupling, the hydraulic control system with the possibility to integrate several different
functions in a compact and efficient solution, the winch torque sensor and motor angular sensor, which are
specifically designed to merge with the components, provide fundamental information for the defined control
strategy and also for safety assurance and the central control unit and its software providing an efficientintegrated
control strategy and a user-oriented capability for personalization.

The paper presents a methodology for calculating the pressure loss in unsteady flows through concentric annular
channels. The momentum equation in axial direction is solved in the Laplace domain to obtain the unsteady
radial velocity distribution. Based on the velocity profile, the relation between the Laplace transforms of pressure
loss and area-averaged flow velocity is derived. A time domain representation of this equation is provided for
oscillating flows. For arbitrary temporal distributions of the flow, the inverse Laplace transform of the relation
between pressure loss and flow velocity has to be derived. Since finding the inverse Laplace transform of the
exact weighting function for each possible radius ratio is cumbersome, the annular channel flow is approximated
by a plane channel. An error analysis shows that this approximation introduces errors less than 1 % for channel
geometries down to radius ratios of 0.45. The approximated weighting function is transformed into the time
domain by using the residue theorem from complex analysis. The resulting convolution integral can be used in
one-dimensional hydraulic system simulation software.