In this paper, a new type Electric Hydraulic Actuator(New EHA) adopted variable displacement pump is presented to enhance the dynamic response of EHA. This system combines the advantages of electric with hydraulic systems and it is easy to be integrated with the whole electric system, which is a promising tendency to save energy and enhance control performance. Firstly, the basic principle and the difference with the traditional EHA are introduced. Moreover, the mathematical model is constructed. Then, the controller by using the fuzzy algorithm is designed. Finally, the simulation and experiment for the New EHA are investigated, both of the results show the effectiveness of the New EHA.

A mathematical model of the acoustic emission signal during a grinding cycle is proposed for the monitoring of material removal in precision cylindrical grinding. Acoustic emission signals generated during precision grinding are sensitive to forces in grinding and present opportunities in accurate and reliable process monitoring. The proposed model is developed on the basis of a traditional grinding force model. Using the developed model, a series of experiments were performed to demonstrate the effectiveness of the acoustic emission-sensing approach in estimating the time constant and material removal in grinding. Results indicate that acoustic emission measurements can be used in the prediction of material removal in precision grinding with excellent sensitivity.

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