Abstract
A method for estimating an actuator gripping force for estimating, as a gripping force of a fluid pressure actuator, a force acting in a direction orthogonal to a tube axis of the fluid pressure actuator when the tube axis is not curved due to curvature, in which the fluid pressure actuator includes a tubular main body portion having a tube circumference of which one side is shortened in a tube axis direction and curved due to increase in internal pressure in a tube, a proximal end side of the fluid pressure actuator along the tube axis is fixed to a base body, and a distal end of the fluid pressure actuator moves relative to the base body, the method including estimating the gripping force using Equation F=ω 1 P(L−L min )+ω 2 , where L represents a length from one end portion to the other end portion of the most contracted side surface of the main body portion, P represents the internal pressure in the tube, F represents the gripping force, ω 1 and ω 2 represent parameters set based on basic characteristics of the fluid pressure actuator, and L min represents a constant based on geometric characteristics of the fluid pressure actuator.