Kinematics and Control of Automatic Machines

The drive, irrespective of its nature, imparts the required movement to the tools through a mechanical system that controls the sequence and regularity of the displacements. Every mechanism has a driving link and a driven link. The first question in kinematics is that of the relationship between the input and the output. In all the examples discussed, neither the position function nor the kinematic properties can be modified after the dimensions and shapes are established. However, this lack of flexibility can be overcome by altering the design. The requirements dictated by the timing diagram vary, but they can often be met by using cam mechanisms. The idea underlying such mechanisms is made clear by the use of a diagram, in which a disc cam is presented schematically. The chapter also discusses the problem of motion errors caused by dynamics. It is convenient to use the cam mechanisms as an illustration. The position function of the mechanisms can be chosen from a very wide range of possibilities.