A MEMS-based flexible sensor and actuator system for space inflatable structures

Inflatable and other membrane structures are expected to become increasingly important in space exploration due to their light weight and low cost. Unlike rigid structures, these structures are typically fabricated of flexible polymers and require internal pressurization to achieve structural integrity. Due to this, inflatable structures are vulnerable to the harsh space environment and catastrophic failure from structural vibration. A MEMS-based health monitoring and control system (HMCS) for space inflatables has been developed at the University of Arkansas. Fabricated mostly from polymeric materials, the HMCS is lightweight, flexible and can be attached directly to the external surface of an inflatable to provide health monitoring. Structure-wise, the HMCS is a three-dimensional multichip module with a sensor layer at the top, a common polyimide substrate in the middle and an actuator layer at the bottom. The sensor layer consists of an interconnected network of MEMS sensors for monitoring the environmental conditions around the inflatable and also the structural vibration of the inflatable. The actuator layer, fabricated from electroactive polymers, provides a two-dimensional shape control capability to the HMCS. When operated with strain and vibration sensors in the sensor layer, the polymer actuator can deform the surface contour of the inflatable to remove 'wrinkles' and dampen structural vibration.