Robot with joints of variable rigidity and method for calculating said optimized rigidity

摘要

A jointed robot capable to move on a surface is provided. It is known to limit to a predefined fixed value the torque that the motors of the joints of the robot can develop. A rigidity coefficient corresponding to the limit torque is calculated by solving a dynamic equilibrium model of the robot. The contact points of the characteristic effectors are determined by a selection from a list of potential effectors, notably as a function of a criterion of distance from a virtual ground plane. The contact forces for said effectors are calculated by optimal resolution of the equilibrium equations. Finally the torques applied in the dynamic equilibrium model of the robot and the coefficients of corresponding rigidity are calculated.

主权项

1. A robot with capabilities of displacement on at least one jointed chain comprising:
at least one sensor of contact of an end of an at least one jointed chain with a displacement surface, said at least one jointed chain including at least one joint, said at least one joint driven by an electric motor controlled by an order determined based on a position and/or a velocity and based on limiting a current and/or a torque applied to said electric motor,
wherein said limiting is controlled as a function of the torque applied to said at least one joint, said torque being calculated as a solution of an equation modeling a dynamic equilibrium of the robot between:
a first sum of: (i) a difference of inertial forces due to an angular acceleration of the at least one joint, (ii) the gravitational acceleration, (iii) an effect of Coriolis forces, and (iv) centrifugal forces, anda second sum of: (i) the torque, (ii) contact forces, (iii) friction forces, and (iv) perturbation forces, said torque and said contact, friction and perturbation forces being applied to said at least one joint,wherein a part of effects of the inertial forces due to the angular acceleration of the at least one joint, effects of the Coriolis forces and centrifugal forces, and effects of the friction forces being modeled by an offset to a variable rigidity coefficient, andwherein said friction forces are limited by the variable rigidity coefficient calculated for the at least one joint.