Modeling and Control of Dielectric Elastomer Enabled Cuff Device for Enhancing Blood Flow at Lower Limbs

Orthostatic hypotension, deep vein thrombosis (DVT), and edema are venous system disorders that affect the lower limbs and are common causes of decreased work performance and affect the lives of many individuals. Compression devices, rotation of staff, and regular breaks can alleviate these problems. Active compression devices use air compression and require a pump, making them bulky. A calf muscle device that uses a dielectric elastomer as a soft actuator that is compact, lightweight, and resilient, making it convenient for use is developed. In this study, a physics-based model of the device is presented by combining the physics of a thin-walled dielectric elastomer vessel with the force interactions between the active vessel and the cylindrical passive elastomer within. The couplings between the two nonlinear elastic models are solved and a control-oriented model that is capable of capturing the pressure change experienced by the device under an applied voltage is established. A prototype of the device is made and characterized. The model is validated in the normal frequency range of the device. Human pulse signal tracking is then performed using adaptive iterative learning control (ILC) in a feedback loop. Experimental results have shown that the device can generate up to 10 Pa fluid pressure difference while tracking a human pulse signal with almost zero phase delay. Note to Practitioners-This paper describes a method that enhances blood flow using a comfortable soft cuff device. The device is made of dielectric elastomer which can generate contractions when it wraps around a lower limb to help circulate blood flow. Development of the cuff device could provide a preventive and proactive tool, as well as a rehabilitation tool, for regulating and improving blood flow. For example, this device could help a passenger who takes a long time flight to circulate his/her blood flow. This device could also help an athlete improve his/her muscle performance in highly intensive competitions. This paper details design, modeling, fabrication, and control of the device. A prototype of the device was fabricated and was able to generate enough contractions on an artificial lower limb to influence the blood pressure while tracking a human pulse signal. Experimental results have shown a great promise in enhancing blood flow with such a wearable and comfortable device.