Step 1: The position of the via points (for point 𝑉 𝑝 𝑖 , ( 𝑋 𝑉 𝑝 𝑖 , 𝑌 𝑉 𝑝 𝑖 ) )
is pre-defined in the algorithm (Figure 7(b)). Detection flag (D-Flag)
and Point-Flag (P-Flag) are two status flags to determine the status
of the robot. P-Flag indicates the next via point that should be
reached. D-Flag indicates if the via points are followed.
Step 2:
If 𝛼 < 0 and 𝛽 < 0 and D-Flag = 0, then P-Flag = 1 and D-Flag = 1.
If 𝛼 > 0 and 𝛽 < 0 and D-Flag = 0, then P-Flag = 2 and D-Flag = 1.
If 𝛼 < 0 and 𝛽 > 0 and D-Flag = 0, then P-Flag = 5 and D-Flag = 1.
Step 3: If P-Flag = 𝑖 , 𝑋 𝑟 = 𝑋 𝑟 𝑋 𝑉 𝑝 𝑖 , and 𝑌 𝑟 = 𝑌 𝑟 𝑌 𝑉 𝑝 𝑖 .
So, the calculation of feedback parameters is changed.
Step 4: The control algorithm (Algorithm 2) is then followed
to reach the specified via point.
Step 5:
If P-Flag = 4, then steer to the actual target frame.
If P-Flag = 3 and 𝑒 , then P-Flag = 4.
If P-Flag = 6 and 𝑒 , then P-Flag = 4.
If P-Flag = 2 and 𝑒 , then P-Flag = 3.
If P-Flag = 5 and 𝑒 , then P-Flag = 6.
If P-Flag = 3 and 𝑒 , then P-Flag = 4.
If P-Flag = 1 and 𝑒 , then P-Flag = 2.
Step 6: Steps 2–5 are repeated once a new image frame arrives.
Algorithm 3: The algorithm to follow the via points.