Modeling of a Pneumatic Strain Energy Accumulator for Variable System Configurations With Quantified Projections of Energy Efficiency Increases

The pneumatic Strain Energy Accumulator (pSEA), a device that stores the energy of compressed air in the strain energy of a rubber bladder, has recently undergone proof of concept testing showing promise in compact energy storage applications. An adequate model of the pneumatic strain energy accumulator on a systems level is needed to explore the design space in order to optimize the device. The recent success of the pneumatic strain energy accumulator on an Ankle Foot Orthosis (AFO) medical assist device serves as motivation for such a systems level model. In laboratory experiments the AFO medical assist device has reported from 25–75% energy efficiency improvement when using the pSEA depending on the various parameters of the medical device. Early measurements and calculations for a single stage independent process pSEA indicated a theoretical maximum energy efficiency increase of 33% which lies between the energy efficiency values realized on the AFO device using a single stage coupled process pSEA. A study of a lumped parameter model using measured Pressure-Volume curve data as a model input will be used to quantify energy efficiency increases for a variety of system configurations. Once complete, a set of measurement techniques and tools to successfully realize the strain energy accumulator will be ready to use in quantifying its energy savings.