In this paper, an active yaw system with valve-controlled hydraulic motor is designed. Correspondingly,
the accurate control method of vane direction based on pressure difference feedback is presented. Then
the simulation analysis is conducted in AMESim. The simulation results show that the control method
presented in this paper is efficient. Moreover, the control accuracy can be improved by decreasing the
friction torque or adding a friction compensation link into the controller. At last, an experimental
platform is built to verify the feasibility of the control method presented. The achievements provide
theoretical and practical guidance for the design of wind turbine active hydraulic yaw systems.

This article presents an innovative technology of energy management for a conventional hydrostatic-split power
transmission (CH-SPT) system used in front end loader (FEL). A fuel efficient controller and a DC generator
are additionally connected in parallel with the load shaft of the drive to prevent the engine and the major
hydraulic components from over-loading or under-loading conditions. Detailed simulation model of the system,
so called Regenerative Hydrostatic-Split Power Transmission (RH-SPT) system is made in the
MATLAB®/Simscape environment. The performance analysis and the fuel consumption of the RH-SPT drive is
compared with that of the CH-SPT drive through simulation. It is observed that with increase in 10% fuel
consumption, the electric power regeneration through the DC generator increases by 21% of maximum power
generated in CH-SPT drive.

In the current cooling system structure of machine tools is a central fixed pump provides a constant cooling volume flow to cool all the components of the machine tool. The provided cooling volume flow does not match the temperature development of each component. This may lead to some of the components heating up while the other components are simultaneously being cooled. Due to these temperature differences, a thermo-elastic deformation of the machine structure occurs. This deformation is responsible for the displacement of the Tool Centre Point (TCP) of the machine tools. Consequently, the machine’s accuracy during the production process is reduced.
The main goal of this paper is to analyse the thermal behaviour of the current cooling system structure of two demonstration machines and to present a simulative study of new cooling system structures under consideration. The investigation of this research will examine the effectivity as well as the temperature characteristics of the components of the new structures under consideration comparing them to the current cooling system structure in order to ensure a uniform temperature distribution of the machine tool at minimal energy consumption.
The results show that the new concepts have great potential in respect to better thermal behaviour and lower hydraulic power compared to the current cooling system structure. The simulation results show a more stable temperature profile of the components as well as a lower energy consumption of the cooling system.

A new energy efficiency evaluation method, based on least squares combination weight (LSCW), is proposed in this paper. Furthermore, the method is based on the thorough analysis of Fuzzy Analytic Hierarchy Process (FAHP) and Information Entropy (IE). Because of the multi-parameter characteristic of the ammonia refrigeration system, some critical parameters are firstly selected with the help of detailed simulation. Subsequently, a new two-dimension matrix constructed by these parameters is designed. According to the actual working system, compared with the FAHP and IE, results show that the new method has better precision, smaller relative error and greater consistence with actual energy efficiency change.