Patent ID: 7658246
Filing Date: 2010-02-09
Classification: B25J,B62D,Y10T

Abstract:
1. A leg joint assist device of a legged mobile robot, wherein the legged mobile robot is equipped with a plurality of legs constructed by consecutively installing a plurality of link members from its body through the intermediary of a plurality of joints, the leg joint assist device comprising: a spring means attached to at least one of the link members, for generating an assisting driving force to be imparted to a specific joint, together with a driving force of a joint actuator attached to the legged mobile robot for driving the specific joint, by the elastic energy accumulated in response to a relative displacement motion of a pair of link members connected by the specific joint, at least one joint of the plurality of joints of each leg being defined as the specific joint, wherein the spring means comprises a cylinder, a piston provided such that the piston slidably moves in the cylinder in response to a relative displacement motion of the pair of link members, a pair of air chambers that are formed on both sides of the piston in the cylinder and whose volumes change in response to a sliding movement of the piston, at least one air chamber of the pair of air chambers being a spring-gas-charged chamber, and a gas charged in the spring-gas-charged chamber, the spring means elastically generating the assisting driving force by compression or expansion of the gas in the spring-gas-charged chamber as the piston slidably moves; and a gas passage provided in the spring means such that the gas passage brings the spring-gas-charged chamber into communication with outside if a relative displacement amount of the pair of link members falls within a predetermined range set beforehand, while the gas passage shuts off the spring-gas-charged chamber from outside by the piston if the relative displacement amount deviates from the predetermined range, wherein if a relative displacement amount of the pair of link members falls within the predetermined range, then the gas is circulated between the spring-gas-charged chamber and outside through the gas passage in response to a sliding movement of the piston according to a relative displacement motion of the pair of link members, thereby preventing compression or expansion of the gas in the spring-gas-charged chamber.