ABSTRACT

This chapter discusses a discrete strategy for controlling a second-order system. It introduces the concept of discrete control systems. These systems respond in a ballistic fashion. A discrete correction is executed in an all-or-none manner without being influenced by feedback. For the first-order lag and the second-order lag, control is accomplished by proportional adjustments to continuously monitored "error" signals. A critical difference between the bang-bang style of control and the first-order lag or second-order lag model is the relation between instantaneous magnitude of error and the magnitude of control action. There are many control situations where the human operator must sample multiple sources of information. Control strategies that include a coast phase tend to reduce fuel consumption. Hghly skilled gymnasts were losing control, suggesting that there were open-loop components to this skill that were out of tune with the unexpected height of the vault.