Patent ID: 11965620
Assignee: SOUTHEAST UNIVERSITY
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  B | IPC B  F

Claim 5:
6. A control method for the pipeline patrol inspection robot having variable tracks of claim 1, wherein each of the track assemblies comprises the driving wheel, a tensioner and a three-dimensional force sensor disposed on the tensioner of each of the track assemblies, and
wherein the method further comprises the following steps:
step 1: sampling Y-axis direction force values and Z-axis direction force values outputted by the three-dimensional force sensor at a sampling frequency of 100 Hz, and performing filtering by using a median averaging algorithm to obtain a Y-axis direction force FY1 and a Z-axis direction force FZ1 of the track assembly on the left side of the robot and a Y-axis direction force FY2 and a Z-axis direction force FZ2 of the track assembly on the right side of the robot;
step 2: calculating a ratio of the Y-axis direction force to the Z-axis direction force for each of the track assembly on the left side of the robot and the track assembly on the right side of the robot, which are α1 and α2, wherein, α
       1
      
      =
      
       
        F
        
         Y
         ⁢
         1
        
       
       
        F
        
         Z
         ⁢
         1
        
       
      
     
     ,
     
      
       α
       2
      
      =
      
       
        F
        
         Y
         ⁢
         2
        
       
       
        F
        
         Z
         ⁢
         2
        
       
      
     
    
   
   
    
     (
     1
     )
    
   
  
 

step 3: calculating a determination basis for track camber angle adjustment, and selecting a proper control algorithm:

Δ1=|α1|−δ  (2)

Δ2=|α2|−δ  (3)

η=α1α2  (4)

μ=Δ1−Δ2  (5)

wherein δ is a set positive threshold, and when α1>δ and α2>δ, the track assembly on the left side of the robot and the track assembly on the right side of the robot are both required to be expanded outward;
when −α1>δ and −α2>δ, the track assembly on the left side of the robot and the track assembly on the right side of the robot are both required to be retracted inward;
in the above two states, the two push rod motors are simultaneously controlled by using a gradient descent method, to adjust a track camber angle to quickly approximate an optimal state, that is, Δ1≤0 or Δ2≤0;
in case of approximating the optimal state, that is, Δ1 ≤0 or Δ2 ≤0, or when the track assembly on the left side of the robot and the track assembly on the right side of the robot are both required to be adjusted clockwise/counterclockwise, that is, Δ1 >0, Δ2>0, and η<0, a “fixing one while moving the other” proportional-integral (PI) control method is adopted, and the “fixing one while moving the other” PI control method comprises the following: if η>0, PI control is performed on only a left push rod motor to adjust a camber angle of the track assembly on the left side of the robot so that α1=0, and on the contrary, PI control is performed on only a right push rod motor to adjust a camber angle of the track assembly on the right side of the robot so that α2=0, until an optimal state of contact between a track surface and a pipe wall is realized, that is, α1=0 and α2=0; and
step 4: when the robot passes through a diameter-varying area of the pipeline or an irregular pipeline area, automatically monitoring a state of the contact between the track assemblies and the pipe wall by steps 1-3, if it is detected that the track is in a non-optimal state, first adjusting a universal joint to a proper angle by using a servo motor, and then automatically adjusting the track camber angle to the optimal state by using the track angle adjusting mechanisms, wherein
the above steps 1-4 are adaptive adjustment steps of the track camber angle, the movement of the robot is realized by the movement driving mechanisms, and steering of the robot is controlled by using a left and right track differential method.