Deadbeat Sampled System Direct Synthesis
Calif. · 1963
Summnry-A direct synthesis method is presented for obtaining a discrete compensator to produce a hite-settling-time transient in response to a prescribed input with no intersample transient terms after the iinite settling time. The method is applicable to a single constant-frequency sampler in a feedback system with any type of hold for any polynomial input. The method uses a fictitious sampler at the output with sample time T/iX to scan the intersample times and to obtain criteria for deadbeat transients. The criteria are derived from root locus considerations but are applied to Laplace transforms containing both functions of s and functions of z so that the only operations are analytic ones. IKTRODCCTION A TYPICAL sampled-data system contains a dynamic member including a transducer and source of energ>-. The energy flows ton-ards the job to be done through the d?-namic member which can usually be approximated by a linear differential equation. The measurement of the performance is the feedback branch and this is quite commonly a sampled-data information link. The command is also sampled and the command minus the feedback is therefore a sampled error. If possible, some processing of the error signal is done b>- a digital computer or a discrete compensator prior to introducing a zero-order hold and prior to converting the processed sampled-error signal into a continuous input to the dynamic member.