Vertical Wind-Tunnel Testing of Steerable Cruciform Parachute System

Abstract

This paper presents an experimental approach for testing a steerable cruciform parachute system using a vertical wind tunnel. A controller to stabilize the canopy heading is developed and tuned. A model that captures the open-loop heading dynamics is identified, and a rudimentary estimate of the glide ratio (GR) is obtained using inverse dynamics. The heading stabilization controller developed during the vertical wind-tunnel experiments is applicable during outdoor flight testing with only minor modifications, and the open-loop heading model and GR model both produce results that are consistent with data collected during outdoor flight testing. The vertical wind-tunnel testing methodology itself is discussed in terms of the cost and time savings as compared to traditional outdoor flight testing. Additionally, the extensibility of the vertical wind-tunnel testing methodology to other parachute systems is discussed. The vertical wind-tunnel approach to testing a system like the steerable cruciform provides the capability to investigate the viability of an untested parachute system rapidly while still providing realistic performance, thereby creating a repeatable and inexpensive alternative to outdoor flight testing.