A-34 交叉角付き2動輪式ピッチングマシンによるいくつかの投球例(野球2(FD))

抄録

A commonly used pitching machines equipped with two same diameter wheels parallel to each other can only pitch balls such as a straight ball and a curve ball, whose angular velocity vectors are perpendicular to their translational directions. Actually, the balls pitched by real pitchers have the angular vector directions slanted to the translational directions. To overcome the defect of this type pitching machine a new pitching machine has been invented to pitch a gyro-ball and slider ball, whose angular velocity vectors are not perpendicular to the translational directions. This is achieved by arranging the two wheel shafts of a pitching machine to be twisted. To control the pitching machine for an arbitrary angular velocity vector of the ball and its velocity formulas are derived to define the surface velocities of the two wheels and their twist angles.