MODEL S,a sampled-data simulation language

Abstract

Existing general purpose simulation software is not adequate for studying large, flexible spacecraft with digital controllers because it will not accept sampled-data equations or link to state-of-the-art structural modeling software. The MODEL S sim ulation language was developed to handle the first of these problems. It will accept mathematical models involving both differential equations and sampled-data equations. Computa tional delays can also be included. This makes MODEL S useful for the simulation of many digital controllers. Simple examples and an actual spacecraft controller show the language's power, flexibility, and ease of use. Planned enhancements include multirate sampling capability, software mode control and event sensing, and linkage to complex plant models.