Page 49 - Read Online
P. 49

Page 142                         Ortiz et al. Intell Robot 2021;1(2):131-50  I http://dx.doi.org/10.20517/ir.2021.09


                                           g(x ,x )
                                             i  j
                                         100
                                             x                                 B SLAM
                                          90  i
                                          80
                                          70                                  f*
                                          60
                                         y [m]  50
                                          40
                                          30
                                          20
                                          10
                                          0
                                           0  10  20  30  40  50  60  70  80  90  100
                                                            x [m]
                                        Figure 3. Sliding mode simultaneous localization and mapping.


                                         100    B            f*    x
                                                 obs               T
                                                                           B
                                          90                                SLAM
                                          80
                                          70
                                          60
                                         y [m]  50
                                          40
                                          30
                                            x
                                             S
                                          20
                                          10
                                          0
                                           0  10  20  30  40  50  60  70  80  90  100
                                                            x [m]
                    Figure 4. Autonomous navigation using sliding mode simultaneous localization and mapping and genetic algorithm method.


               5.1.  Simulations
               The following simulations were implemented in partially unknown and completely unknown environments.
               The size of the environments was 100 m × 100 m, in which a solution was sought to find a trajectory from the
               initial point       to the target point       . The sliding mode gains were selected as    =         ([0.1, · · · , 0.1]).

               In the partially unknown environments,           (0) ≠ ∅. The path planning solution    was partial because
                                                                                        ∗
               the environment           (  ) was variant in time. Figure 3 shows a partial solution    from an initial point       to
                                                                                   ∗
               the objective point       for the partially unknown environment. Figure 4 shows the overall result of the robot
               navigation from point       to point       with the robust SLAM algorithm combined with the GA.

               Here, the SLAM algorithm was used to construct the environment and find the position of the robot. At the
               beginning of navigation in the partially unknown environment, there was a planned trajectory of navigation
               through the GA algorithm; however, if an obstacle was found in the planned trajectory, the GA algorithm
               needed to be used to search for a new trajectory within the built environment by the SLAM,            . The
               planned trajectory belonged to the set of obstacles that prevent reaching the goal,    ⊂           (  ); therefore, it
                                                                                     ∗
               was necessary to look for a new trajectory using RGA that allowed reaching the goal.


               For the completely unknown environments,           (0) = ∅. In these environments, the SLAM algorithm was
               required to know the environment             and the position of the robot; in this way, when an obstacle was
               found that contained the planned trajectory, a new trajectory with the GA algorithm was searched on the map
   44   45   46   47   48   49   50   51   52   53   54