Recognition for Frontal Emergency Stops Dangerous Activity Using Nano IoT Sensor and Transfer Learning

Currently,it is difficult to extract the depth feature of the frontal emergency stops dangerous activity signal,which leads to a decline in the accuracy and efficiency of the frontal emergency stops the dangerous activ-ity.Therefore,a recognition for frontal emergency stops dangerous activity algorithm based on Nano Internet of Things Sensor(NIoTS)and transfer learning is proposed.First,the NIoTS is installed in the athlete’s leg muscles to collect activity signals.Second,the noise component in the activity signal is removed using the de-noising method based on mathematical morphology.Finally,the depth feature of the activity signal is extracted through the deep transfer learning model,and the Euclidean distance between the extracted feature and the depth feature of the frontal emergency stops dangerous activity signal is compared.If the European distance is small,it can be judged as the frontal emergency stops dangerous activity,and the frontal emergency stops dangerous activity recognition is realized.The results show that the average time delay of activity signal acquisition of the algorithm is low,the signal-to-noise ratio of the action signal is high,and the activity signal mean square error is low.The variance of the frontal emergency stops dangerous activity recognition does not exceed 0.5.The difference between the appearance time of the dangerous activity and the recognition time of the algorithm is 0.15 s,it can accurately and quickly recognize the frontal emergency stops the dangerous activity.

Multifunctional Measurement System for High Precision Planetary Servo Gearhead

As an essential component of a servo system,mechanical properties of high precision planetary servo gearhead direct influence on the validation,stability and accuracy of the servo control system.However,mechanical properties measurement and assessment for high precision planetary servo gearhead is a time-consuming and tedious work,since current methodologies typically rely on various different specified systems.An integrated multifunctional measurement system SFJC-I is developed,which employs a torque sensor and a laser displacement transducer to simultaneously measure torque applied on servo gearhead and its corresponding torsional deformation.The measurement system depends on the accurate measurement of the relative displacement between input clamping system and output shaft of servo gearhead with a lever-type enlarging mechanism,rather than traditional optical dividing head and optical multisurface prism.Using interchangeable fixture system,the developed system capability to measure almost all series and specifications of high precision planetary servo gearhead is demonstrated.With proposed hardware platform configuration and developed measuring software,mechanical properties such as backlash,torsional stiffness,hysteresis plot and emergency stop torque,can be measured accurately and assessed reliably.A torsion test with standard circular specimen is carried out with the multifunctional measurement system.The result of test shows that the measurement error is within ±3σ and the measurement reliability is more than 99.97%.The problem of accurate measurement and reliable assessment of mechanical properties for high precision planetary servo gearhead is fully solved with the developed multifunctional measurement system.