Research on Hand-Transmitted Vibration Prediction Model of the Handheld EVA Power Tool

The hand-transmitted vibration generated by extravehicular activity (EVA) power tools has an important impact on the health of astronauts and the efficient completion of maintenance tasks when astronauts use EVA power tools for on-orbit maintenance. Based on the hand-transmitted vibration zero-gravity simulation test platform to measure the vibration response of the EVA power tool to human hands. Given the influence of the length of the operating rod and the number of non-detaching fastening devices on daily vibration exposure when astronauts wear extravehicular spacesuit gloves, a second-order polynomial model and a quadratic cumulative nonlinear model of daily vibration exposure are established. The experimental results show that the second-order polynomial model is more explanatory and predictive of the test data in the scope of the test. The R-values of the palm and opisthenar prediction model are 0.9930 and 0.9940 respectively, and the RMSEs are <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>7.973</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></mrow></semantics></math></inline-formula> m/s² and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.034</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></semantics></math></inline-formula> m/s². The quadratic cumulative nonlinear model can accurately predict the vibration exposure of the hand outside the scope of the test. This study can provide theoretical reference and data support for the prediction of vibration exposure generated by astronauts using the EVA power tools during on-orbit maintenance.