Gaits of controllers evolved by ENSO for quadruped with knees. As in the experiments without knees, ENSO evolved symmetric and regular trot gaits for this challenging morphology as well. This video shows two such gaits coordinating the hip and knee joints for effective locomotion.
Gaits of controllers evolved with handdesigned S8 symmetry for quadruped with knees. As this video shows, these controllers make all legs move synchronously, resulting in ineffective pronk gaits that travel only a small distance.
Gaits of controllers evolved with handdesigned D2 symmetry for quadruped with knees. This video shows that fixed D2 symmetry can also produce regular gaits similar to those produced by ENSO, but they are typically less effective and are produced less often.
Random Symmetry Evolution
Gaits of controllers produced by random symmetry evolution for quadruped with knees. In contrast to the smooth and regular gaits evolved by ENSO, random symmetry evolution produces awkward and irregular gaits such as in this video. As a result, these gaits are likely to be less effective in the real world.