For horizontal-axis wind turbines, wind turbines typically alignment nacelle to the wind using yaw system, realizing max energy capture. If the wind turbine’s nacelle has a large error to the wind, the captured wind energy loss will be large, and it will also cause an increase in the load of the unit, which will pose a major risk to the safety of the wind turbine. Affecting the wind measurement error in addition to the performance of the sensor itself, the installation position of the wind measurement equipment also accounts for an important factor, this paper on the basis of the calculation of fluid dynamics simulation results, through the lateral and longitudinal comparison of the simulation results, pointed out the best installation location of the wind direction sensor, optimize the loss caused by wind measurement error of wind turbine in design, and provide guidance for the installation of the wind direction sensor on site.

The elderly are prone to fall during walking, which not only leads to injury but also can cause permanent disability or even death. Thus, it is crucial for the walking-assistant robot to prevent the elderly from fall during walking. However, the factors affecting the steadiness of the elderly are not considered comprehensively in the existing studies of elderly fall prevention model and control schemes. In this paper, a novel control method of the elderly-assistant robot for preventing elderly fall is proposed by considering the two main factors affecting steadiness of the elderly, namely, position and velocity of the center of mass. Initially, the dynamics of the robot system for preventing elderly fall are derived respectively from different elderly fall situations. Then, the elderly-assistant robot is controlled to stop at an appropriate position, and to minimize the tilt angle as small as possible to avoid overturned. The control system ensures that the position-velocity coordinates of the center of mass of the elderly reach the dynamic steadiness region which guarantees human balance. Finally, the results of the simulation and the experiments show that the proposed control method of the elderly-assistant robot can be effectively used to prevent the elderly fall during walking.

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