Haptic Perception with Self-Organizing ANNs and an Anthropomorphic Robot Hand
Figure 4
The test results of the four systems. (a) The SOM-based system is organized according to shape and size. Groups of large blocks, small blocks, large cylinders, and small cylinders can be distinguished. The activations tend to be located according to size of the objects in a clockwise manner. Individual objects can be discriminated to a large extent. (b) The GCS-based system produces similar results as the SOM-based system, that is, it is organized according to shape and size. The GCS-based system separates large blocks, small blocks, large cylinders, and small cylinders, and the objects are represented according to size with the smallest objects uppermost and the largest lowermost in the GCS. Also individual objects can be discriminated to a large extent. (c) The GCS-DN based system self-organized into subnetworks, where one or more subnetworks represent the categories large blocks, small blocks, large cylinders, and small cylinders. (d) The GG-based system separates large blocks, small blocks, large cylinders, and small cylinders, and the grid is organized according to size. Individual objects can be discriminated to a large extent. The 6 test objects (indicated with the numbers 1–6) not included in the training set activated neurons at proper locations perfectly in all systems but the GCS-DN based system. In that system, object 1 triggered activation in the wrong subnetwork. (see Table 1 for the meaning of the labels).
