發送短信 : Relay-based friction identification in frequency domain

  _____     _____     ______    _____    _    _   
 / ____||  |  ___||  /_____//  |  ___|| | \  / || 
/ //---`'  | ||__    `____ `   | ||__   |  \/  || 
\ \\___    | ||__    /___//    | ||__   | .  . || 
 \_____||  |_____||  `__ `     |_____|| |_|\/|_|| 
  `----`   `-----`   /_//      `-----`  `-`  `-`  
                     `-`