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For problems of high power consumption, large volume, close irradiation distance and poor concealment of existing auxiliary light source for low-illumination video acquisition, a design scheme of intrinsically safe laser auxiliary light source for low-illumination video acquisition was proposed. The semiconductor laser diode with 940 nm wavelength of light source is selected, and multi-mode fiber, smoothing glasses and lens are used to realize regular shape and uniform illumination intensity of beam outputted by the semiconductor laser diode. The intrinsically safe driving circuit adopts constant current driving mode with overvoltage, anti-reverse connection and anti-static protection. Working temperature of semiconductor laser diode is reduced through heat dissipation device, so that the laser auxiliary light source can work stably for a long time. The test results show that the laser auxiliary light source with irradiation distance is 20 m, power consumption is less than 3 W and continuous working temperature below 50 ℃.

A new type of automatic stair climbing wheelchair can helps the disabled walking up and down the stairs and the ground is designed.By adopting the leg structure and using the mechanical foot and wheel bearing alternately in the up and down the stairs equipment,the process of up and down the stairs is simulated.The fine-tune mechanism which can be used to adjust seat angle,keep the seats level all the time is set.The change of the gravity center in the process of up and down the stairs is analyzed,the results show that the design of wheelchair is reasonable,a disabled people can use it up and down the stairs instead of walking.