Patent ID: 7981059

Claim:
A driving force calculating device for calculating a driving force of a driving section of a power assisting device that is worn by a living body having bones with a joint and a muscle and that assists and/or resists a rotational motion of the joint with use of the driving section fixed to the bones across the joint, the driving force calculating device comprising: a muscle force input section to which an assigned muscle force that is to be generated in assisting and/or resisting the rotational motion is input; and a driving force calculating section for calculating the driving force of the driving section based on the assigned muscle force and on joint torque necessary for the rotational motion, so that the assigned muscle force and the driving force of the driving section generate the joint torque necessary for the rotational motion, wherein, under constraint conditions of the assigned muscle force and the joint torque necessary for the rotational motion, the driving force calculating section calculates the driving force of the driving section by calculating f j so that performance function u(f) has a minimum value, the performance function u(f) being represented by an equation: u ⁡ ( f ) = ∑ j = 1 n ⁢ ( f j A j ) m where n is a sum of (i) the number of a muscle for which an assigned muscle force has not been input to the muscle force input section and (ii) the number of the driving section, j is a numeral order of the muscle for which an assigned muscle force has not been input to the muscle force input section or j is a numeral order of the driving section, f j is a muscle force of a muscle in j-th order or a driving force of a driving section in j-th order, A j is a physiological cross-sectional area of a muscle in a case where j is a muscle and A j is a value based on a maximum driving force in a case where j is a driving section, and m and n are any integer of 2 or more.