Spatio-temporal characteristics of friction torque of rolling bearing for space applications

Via the experimental investigation, the influence of the vacuum degree on the friction torque of the rolling bearing for space applications is studied to explore the spatio-temporal characteristics of the friction torque. The simulation is conducted by means of a special tester and the observed data of the friction torque are processed with the help of the statistical theory. A nonlinear function with the variable coefficient and standard deviation is discovered, revealing that the time series of the friction torque is characterized by the uncertainty of variables and the variability of functions. The result presents that under the condition of the variable vacuum degree, the time series of the friction torque changes from a nonstationary process to a stationary process as the rolling bearing undergoes two stages from initial wear to normal wear. This shows that the friction torque belongs to a nonlinearly and dynamically evolutionary process.