Implementation of whole-body humanoid locomotion

During the development of our first open type joint at Pneumat-BRP, we discovered that a wider range of movement allowed by open-joint articulations has as shortcoming a greater difficulty to effectively control the system.

In human walking gait it has been discovered that muscles called bi-articular muscles play a very important role, connecting links between 2 joints. In order to achieve hopping and running behaviors, we believe that bi-articular muscles play a very important role in controlling movement, helping the control of human-like open joints. This way, Pneumat-BR and Pneumat-BR2 are humanoids which uses human-like muscular structure, including a gastrocnemius muscle between ankle and knee, and rectus femoris and hamstrings across the knee and hip joints. As a result, these robots were capable of walking from standing position, jumping from walking, hopping more than 10 cm and walking without any feedback (Fig. 1). Running behavior was also achieved, with a transition from walking to running, and running behavior for a few footsteps.

Fig. 1 Walking motion of Pneumat-BR2 with open-loop control