Abstract
In this paper, we investigate how the roll-over characteristic of a passivity-based walking robot with flat feet is created and affected by its musculoskeletal structure, which is easily modeled by an agonistic and antagonistic pair of muscles. We hypothesize that the curvature radius and the center position of the roll-over shape (ROS), defined as the centers of pressures transformed into a shank coordinate, is strongly related to the stiffness and the equilibrium posture of the ankle joint, which are determined by the tonuses of the agonistic and the antagonistic muscles. We built a new musculoskeletal biped walking robot driven by pneumatic actuators and conducted exhaustive walking experiment with various ankle conditions. The hypothesis is verified experimentally by analyzing the ROSs of the walking robot.
Zusammenfassung
In this paper, we investigate how the roll-over characteristic of a passivity-based walking robot with flat feet is created and affected by its musculoskeletal structure, which is easily modeled by an agonistic and antagonistic pair of muscles. We hypothesize that the curvature radius and the center position of the roll-over shape (ROS), defined as the centers of pressures transformed into a shank coordinate, is strongly related to the stiffness and the equilibrium posture of the ankle joint, which are determined by the tonuses of the agonistic and the antagonistic muscles. We built a new musculoskeletal biped walking robot driven by pneumatic actuators and conducted exhaustive walking experiment with various ankle conditions. The hypothesis is verified experimentally by analyzing the ROSs of the walking robot.
In diesem Paper studieren wir das Abrollverhalten passiver Laufroboter und zeigen, wie dieses von muskuloskelettalen Eigenschaften abhängt. Das zugrunde liegende muskuloskelettale Modell besteht lediglich aus einem agonistisch-antagonistisches Muskelpaar. Wir stellten dabei die Hypothese auf, dass der Krümmungsradius und das Rotationszentrum der Abrollform — welche wir als Druckzentrum im Unterschenkelkoordinatensystem definieren — besonders von Steifigkeit und Gleichgewichtszustand im Fussgelenk abhängt. Letzere werden wiederum vom Tonus des agonistischen und des antagonistischen Muskels bestimmt. Wir bauten einen neuartigen muskuloskelettalen Laufroboter mit pneumatischen Aktuatoren und führten aufwändige Laufexperimente unter verschiedenen Fussgelenkbedingungen durch. Anhand der Analyse der Abrollformen des Laufroboters konnte die Hypothese schliesslich bestätigt werden.
© by Oldenbourg Wissenschaftsverlag, München, Germany
