Every critical design, where maximum effectiveness of operation is essential, is always a unique problem. No casual arrangement of standard mechanical elements will provide optimum performance. The interaction of the components, with their inevitable errors of size, form, and position, is most important if the functional effects of these errors are to be minimized.

The designer must consider both the kinematics and the dynamics of the mechanical elements involved, and the influence of the several types of errors as they affect the intensities of the dynamic loads and the momentary shifts of essential elements from their correct positions. The common practice of designing a mechanism by assembling existing components, testing the prototype, correcting the faults that develop, and treating each component as a separate entity will never produce as effective a design as one where the influence of each component on the performance of the system as a whole is carefully analyzed at the initial design stages. If existing components do not meet the requirements, new ones must be designed or existing ones modified.

Most existing texts on mechanical design are generally concerned solely with the kinematics of the motions involved, and completely neglect the dynamics of the system. Webster defines kinematics as: "the science which treats of motions considered in themselves, or apart from their causes ", while dynamics is defined as: "that branch of mechanics treating of the motion of bodies (kinematics) and the action of forces in...