Floor shape deducing device for legged mobile robot

A system for controlling a legged mobile robot having at least a body and a plurality of legs each connected to the body through a first joint and having a foot connected to its distal end through a second joint, the system having a compliance mechanism which deforms in response to a floor reaction force acting from a floor with which the foot is in contact and joint displacement means which displacing the first and second joints such that the foot follows a desired position and/or posture, comprising:

• a. inclination detection means for detecting an inclination of the body relative to a vertical direction;
• b. walking environment foot position and/or posture calculating means for calculating a position and/or posture of the foot in a walking environment including the floor with which the foot is in contact, based on an actual and/or desired position and/or posture of the foot and the detected inclination;
• c. deformed foot position/posture calculating means for calculating the position and/or posture of the foot with deformation of the mechanism in response to the floor reaction force acting from the floor in the walking environment using a mechanism compliance model which models the compliance mechanism;
• and
• d. floor shape estimation value calculating means for calculating a floor shape estimation value indicative of shape of surface of the floor with which each foot is in contact and indicative of a relationships therebetween.