發送短信 : Design, manufacturing and testing of a landing gear wheel mechanism for a quadcopter

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