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In order to improve the life quality of lower extremity amputees, many researchers have studied the powered knee-ankle prosthesis. Various parameters must necessarily be adjusted for the finite state machine impedance model method. Hybrid zero-dynamic (HZD) assumptions are ideal, and with this method measurement information of existing sensors can be limited. The virtual constraint method offers better comprehensive performance at present and can realize the continuous control for the whole gait cycle. The problem with virtual constraint is mainly the selection of phase variables. The joint trajectory of the virtual constraint is derived from a healthy individual, but the joint trajectory of the amputee's normal walking is difficult to obtain. In response to the above problems, this paper proposes an instinctive human joint trajectory, selecting the phase variable associated with the hip joint angle and angular velocity. The Fourier transform solves the expression of the joint trajectory, and the virtual constraint unifies the control method of the entire gait cycle. The simulation results prove the feasibility of the scheme.

Pumped Storage Hydroelectricity (PSH) is a very important method for energy storage. The cycle of water usage, starting with using excess energy, is of great significance for saving energy and improving social and economic benefits. This paper focuses on the analysis and prediction for the ten years' development potential of PSH in China. By analyzing the basic principles and computation methods to understand how PSH works. There are introductions and explanations of two huge PSH projects to determine the current advantages and suggest improvements. Based on China's current national conditions and geographical regions, PSH is suitable and being promoted to be developed, and it will help the country reach the objective of carbon peaking by 2030 and carbon neutrality by 2060. By comparing PSH to its potential competitor, Solid Gravity Energy Storage (SGES), the advantages of maturity and applicability of PSH in China allows PSH to be developed better. Therefore, the thesis evaluated the PSH's future development and concluded that this technology should be promoted in the future.

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