1. Field of the Invention
The present invention relates to an apparatus, a method and a system for resistance-based evaluation of a muscular force.
2. Description of the Background Art
A system for resistance-based evaluation of a muscular force, exploiting a bi-articular link mechanism, such as a bi-articular arm apparatus, has been proposed in Japanese patent laid-open publication No. 2000-210272, for instance. In this known system for resistance-based evaluation of a muscular force, the muscular output of the antagonistic mono-articular muscles and the antagonistic bi-articular muscles of a test subject, or testee, whose muscular force is being evaluated, is measured with a pressure sensor. The test subject, or person, exerts the force with maximum isometric effort, at his or her four limbs, in a plurality of preset directions. Then, a hexagonal diagram showing characteristics of the output distribution is prepared to use the so prepared diagram to evaluate the force of function-based muscles of praxis.
There has also been proposed a model for bi-articular muscles that functions for a mammal inclusive of the human being to bend an arm, and researches are now underway with the use of the model to control the movements of the bi-articular link mechanism. See T. Fujikawa et al., “Functional Coordination Control of Pairs of Antagonistic Muscles”, Transactions of The Japan Society of Mechanical Engineers, Vol. 63, No. 607 (1997-3) pp. 769-776, Treatise No. 96-1040. In this research, it is stated to be desirable to use, as a driving source, a model of an actuator having an elastic element and a contractile element that exerts the force in the contracting direction.
In the above-described conventional solutions for resistance-based muscular force evaluation, the four limbs of a test subject are simulated to a link system, and a muscular force is evaluated based on a hexagonal diagram plotting characteristics of output distribution. Since the hexagonally-shaped output distribution, plotted on the diagram, differs with the joint angles of the link system, measurement cannot be conducted unless proportionally contracted. Further, it is difficult to arrive at proper comparison if the test subject changes his or her position each time his or her muscular force is measured.