Analog-digital (A-D) converters with a fixed conversion time are subject to errors due to metastability. It is shown that an asynchronous converter in which the conversion time is not bounded is faster, on average, than the synchronous design. Real-time applications require the data to be produced within a fixed time, and failures may occur with the long conversion times that can arise with fully asynchronous converters. For these applications, we show that an internally asynchronous bounded time converter is both faster and more reliable than a synchronous converter.

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Taking multi-oil-cavity and multi-oil-pad hydrostatic bearings as studied projects, firstly make brief instructions for structure characteristics and working principal of hydraulic system; Then, build three-dimensional models of multi-oil-cavity and multi-oil-pad hydrostatic bearings respectively. Adopting finite volume method, oil film mesh is generated by universal finite analysis software CFD; then, carry on numerical simulations for pressure distribution and temperature distribution of the two studied hydrostatic thrust bearing under various viscosity, and make comparative analysis for difference between the two studied hydrostatic thrust bearing. Based on the analysis of numerical simulation results, the conclusions whether oil-return groove is set for hydrostatic bearing could be received. Simulation results reveal truly the influence of setting oil-return groove or not on hydrostatic thrust bearing, and improve structure design for hydrostatic thrust bearing.

In order to achieve the switching function of the force and position, the force control is executed when the hydraulic cylinder contacts with the mechanical objects, the position control is executed when the hydraulic cylinder is far away from the mechanical objects. This paper respectively established force control model and position control model. The position control adopts the PID algorithm and the force control adopts the fuzzy algorithm. In order to solve the jump and jitter of the parameters when force-position switching, this paper puts forward a fuzzy switching adaptive control strategy. Fuzzy switching ensures the smooth transition of the two control models, the results of simulations show that fuzzy switching not only ensures the system’s rapidity but also shows excellent robustness against variations of system parameters and external disturbances.

The durability and the accuracy are the critical issues for the design of auto-balance device, which have been well discussed in the literature. However existing solutions were incomplete, they have some defects such as their complicated structure, lots maintenance, poor serviceability and poor balance accuracy. In this paper, we proposed a novel scheme to enhance the durability and the accuracy significantly, which includes three main points: The first, we extract fundamental wave signal with discrete Fourier transform. The second, we adopt electric magnetic drive. The third, we employ planetary gear drive with small teeth difference. The experiment results show that our scheme can achieve satisfactory balance accuracy, which validates our analysis. All the results are obtained by over 1000 hours continuous experiments.