METHOD AND APPARATUS FOR MEASURING DYNAMIC LOAD

摘要

A method and apparatus for measuring a dynamic load without being influenced by vibrations caused by the apparatus itself and the environment. A DLS (the main body of a dynamic load sensor) (10) is periodically vibrated by the reciprocation of a slide base (4) and the vertical movement of a base plate (9). In the DLS (10), one end of a member constituting a spring system is fixed to the base of a non-spring system; the other end is free. A load is applied to the free end of the member constituting the spring system. The base is periodically vibrated continuously together with the member constituting the spring system. The displacement y1 of the base, and the displacement y2 of the free end are continously measured. By using the first derivatives y1 and y2 and the second derivatives ij1 and ij2 of the displacements y1 and y2, the mass m of the load is calculated by the following equation: m[ij]=mg-[(mg+kf2(y-y1+y2))-f3(y-y1+y2)+f1(mij1,mij2)] (where the symbol [] represents a determinant having terms the number of which is equal to the product of the number of degrees of freedom by the number of data, g is the acceleration of gravity, kf2(y-y1+y2) is the material constant of the member constituting the spring system, k is a constant of proportionality, f3(y-y1+y2) is an attenuation term expressing the attenuation such as by viscosity, friction, hysteresis, fluid resistance, or transient state added resistance, and f1(mij1,mij2) is the vibromotive force).