def r_x(phi, r = Const::R_UNIT)
      r_a = Array.new

      begin
        s, c = Math.sin(phi), Math.cos(phi)
        a10 =   c * r[1][0] + s * r[2][0]
        a11 =   c * r[1][1] + s * r[2][1]
        a12 =   c * r[1][2] + s * r[2][2]
        a20 = - s * r[1][0] + c * r[2][0]
        a21 = - s * r[1][1] + c * r[2][1]
        a22 = - s * r[1][2] + c * r[2][2]
        r_a << r[0]
        r_a << [a10, a11, a12]
        r_a << [a20, a21, a22]
        return r_a
      rescue => e
        raise
      end
    end
def r_x(phi, r = Const::R_UNIT)
      r_a = Array.new

      begin
        s, c = Math.sin(phi), Math.cos(phi)
        a10 =   c * r[1][0] + s * r[2][0]
        a11 =   c * r[1][1] + s * r[2][1]
        a12 =   c * r[1][2] + s * r[2][2]
        a20 = - s * r[1][0] + c * r[2][0]
        a21 = - s * r[1][1] + c * r[2][1]
        a22 = - s * r[1][2] + c * r[2][2]
        r_a << r[0]
        r_a << [a10, a11, a12]
        r_a << [a20, a21, a22]
        return r_a
      rescue => e
        raise
      end
    end
=========================================================================
 回転行列（x 軸中心）

 @param:  phi  (回転量(rad))
 @param:  r    (回転行列)
 @return: r_a  (回転後)
=========================================================================