Remote Teleoperated and Autonomous Mobile Security Robot Development in Ship Environment

Algorithm 1

Tangent bug algorithm.

Input:  A robot with a range sensor

Output:  A path to Goal or a conclusion no such path exists

(1) while True do

(2)  repeat

(3)    Continuously move toward the point 𝑛∈ {𝑇, 𝑂_𝑖} which minimizes 𝑑(𝑥, 𝑛) + 𝑑(𝑛, Goal)

(4) until

    the goal is encountered or

    The direction that minimizes 𝑑(𝑥, 𝑛) + 𝑑(𝑛, Goal) begins to increase

     𝑑(𝑥, Goal), that is, the robot detects a “local minimum” of 𝑑(·, Goal)

(5) Chose a boundary following direction which continues in the same direction as the

  most recent motion-to-goal direction.

(6) repeat

(7)    Continuously update 𝑑_reach, 𝑑_followed, and {𝑂_𝑖}.

(8)    Continuously moves toward 𝑛∈{𝑂_𝑖} that is in the chosen boundary direction.

(9) until

    The goal is reached.

    The robot completes a cycle around the obstacle in which case the goal cannot be achieved.

     𝑑_reach<𝑑_followed

(10) end while