• dynamics
• humanoid
• inverted
• pendulum
• safety

EGO is a soft humanoid robot for physical interaction, whose body shape is similar to an inverted pendulum on a cart. Being clearly unstable, this kind of system is recurrently studied for stabilization problems and control. The scope of this work is to analyze a passive system to minimize as much as possible (or even neglect) the consequences given by a collision, while disturbing as minimum as possible the self-balancing of the robot.
Considering the physical limitations related to the body, the system must be as lightweight and highly performant as possible. Thus, the prototype considers springs as a passive system to mitigate the shock and a variation parameter analysis to determine which one influence the most stability while maintaining the objective of damping the collision.
During the investigation, we noticed that its coming back to a working position is needed as well. A reliable standing-up routine is mentioned, as state-flow diagram where switching on and off might be a reasonable solution. By knowing threshold, it is possible to define a region where the system will be directly dependable of the passive system, and with this to avoid drastic and unsuccessful reactions from the control.