The electro-hydraulic position servo control system is a typical complex nonlinear system. It is difficult in achieving the control which has high quality performance.To overcome the effects of non-linearity, parameter uncertainty, external disturbances and load changes, the design of controller is particularly critical. This paper summarizes the controllers which are applied widely: PID controller, fuzzy controller, neural network controller and hybrid controller. Additionally, the paper analyses their performances. At the same time, this paper also points out the prospects of the controllers.

The effect of enhanced solution treatment on microstructures, tensile properties, intergranular corrosion and exfoliation corrosion of a 6013 type aluminum alloy proceeded via various solution treatment were investigated by optical microscopy (OM), scanning electron microscopy (SEM), tension testing and corrosion resistance testing. The results show that compared with the conventional solution treatment (560°C×2 h), the enhanced solution treatment (560°C×2 h+570°C×2 h) can improve ultimate tensile strength and elongation, the corrosion resistance become worse after 151°C×8 h+191°C×8 h artificial aging. The tensile strength increase is believed to resulting from the coarse second phases dissolve. The corrosion resistance decrease is due to grain growth.