ADAPTIVE SAMPLING FREQUENCY FOR SAMPLED-DATA CONTROL SYSTEMS
Abstract
Sampled-data control systems generally have fixed sampling frequencies which must be set high enough to give satisfactory performance for all anticipated conditions. A study is made here of an adaptive system which varies the sampling frequency by measuring a system parameter. It is shown that a sampler followed by a zero-order hold whose sampling period is controlled by the absolute value of the first derivative of the error signal will be a more 'efficient' sampler than a fixed frequency sampler. That is, over a given time interval, fewer samples are needed with the variable frequency system than with a fixed frequency system while maintaining essentially the same response characteristics. The system described reduced the number of samples required for response to a step input to about three-quarters that required in a fixed sampling frequency system. Over a long period of time, savings in the number of samples required can be expected to be between twenty-five and fifty per cent. In many applications, the saving produced by reducing the overall number of samples required may outweigh the added complexity of the adaptive sampling frequency system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1960
- Accession Number
- AD0800700
Entities
People
- Charles A. Phillips
- Merritt C. Farren
Organizations
- Naval Postgraduate School