Patent ID: 7054763

Claim:
A method of estimating floor reaction forces acting on respective leg bodies of a bipedal walking body, comprising: a first step for determining whether a motion state of leg bodies of the bipedal walking body is a single stance state wherein only one of the leg bodies is in contact with the ground or a double stance state wherein both leg bodies are in contact with the ground; a second step for sequentially determining positions of the center of gravity of the bipedal walking body while also sequentially determining accelerations of the center of gravity in an absolute coordinate system fixed with respect to the ground, using time-series data of the positions of the center of gravity; a third step for sequentially determining estimated value of total floor reaction force on the basis of an equation of motion of the centers of gravity represented by a weight of the bipedal walking body, gravitational accelerations, the accelerations of the center of gravity, and total floor reaction force, which is a resultant force of the floor reaction forces acting on the respective leg bodies; a fourth step for sequentially measuring time elapse from a start of the double stance state until an end thereof each time the double stance state begins; a fifth step for measuring a moving speed of the bipedal walking body at least on or before each double stance state begins; a step of sequentially determining estimated values of the total floor reaction force, when the bipedal walking body is in the single stance state, as estimate values of floor reaction forces acting on a single leg body in contact with the ground; and a step of sequentially determining estimated values of floor reaction forces acting on one of the two leg bodies, when the bipedal walking body is in the double stance state, the one leg body being located at the rear side in relation to the direction of travel of the bipedal walking body, on the basis of characteristic data pre-established as indicative of characteristics of changes in floor reaction force acting on the one leg body with respect to the elapsed time of the double stance state and moving speed of the bipedal walking body, and sequentially determining estimated values of the floor reaction forces acting on the other leg body by subtracting the determined estimated values of the floor reaction forces of the one leg body from the estimated values of the total floor reaction force.