A holding structure, such as a manipulator, includes a plurality fingers.
At least one of the fingers is movable such that an object can be held or
released by a closing or opening motion of the movable finger. At least
one contact surface of the fingers, which is capable of being brought
into contact with the object, is formed by an elastic member, and at
least one elastic member is adapted to reversibly change its elasticity
under the control of an external supply of energy to the elastic member.