Patent ID: 11931063
Assignee: MEDTRONIC VASCULAR, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 16:
17. A tissue-removing catheter for removing tissue in a body lumen, the tissue-removing catheter comprising:
an elongate body having an axis and proximal and distal end portions spaced apart from one another along the axis, the elongate body being sized and shaped to be received in the body lumen;
a tissue-removing element mounted on the distal end portion of the elongate body, the tissue-removing element being configured to remove the tissue as the tissue-removing element is rotated by the elongate body within the body lumen;
a motor assembly including a motor and a motor drivetrain output, the motor assembly operatively engaging the elongate body for driving rotation of the elongate body and tissue-removing element mounted on the elongate body; and
a controller operatively connected to the motor and configured to control a speed of the motor, the controller controlling the speed of the motor based on a logistic speed control curve, wherein the logistic curve is based on the equation:, RPM
  =
  
   
    (
    
     
      Θ
      1
     
     +
     
      
       
        Θ
        2
       
       -
       
        Θ
        1
       
      
      
       1
       +
       
        e
        
         (
         
          
           T
           -
           
            Θ
            3
           
          
          
           Θ
           4
          
         
         )
        
       
      
     
    
    )
   
   ⁢
   
    (
    1000
    ), where T is an estimated torque at the motor drive and Θ1, Θ2, Θ3, and Θ4 are predetermined calibration values.