Self-Deployment of a Tape-Spring Hexapod: Experimental and Numerical Investigation

In the framework of developing a future space telescope, this paper focuses on a deployable hexapod equipped with tape-spring coiling devices. It describes the measurement of the platform deployment with a gravity compensation setup. The deployment modeling starts with the formulation of a phenomenological model for a single deployable coiling device. A force-elongation model is built experimentally by measuring the restoring force of such a hysteretic tape-spring actuator. Then, six actuator models are used in parallel to build a complete model of the deployable hexapod. Finally, measured and predicted platform responses are compared. A design of experiments approach highlights that disparities in the restoring force of tape-spring actuators are decisive for deployment success. A regression model is obtained to predict the hexapod’s twist behavior, which is the main indicator of deployment failure. This investigation underlines the requirement of actuator control during deployment.