Most of the conventional sensors used for measuring deformation, pressure, etc., use metal, ceramics, piezo, or the like. Many of them are very rigid, and when the object is deformed or when the pressure on the object changes currently, it is necessary to arrange a large number of sensors with different conditions side by side. However, it is still difficult to measure all changes over time. With the newly developed dielectric elastomer sensor, even a very thin (0.1–0.2 mm) elastomer thickness could be deformed in difficult environments (e.g., places with large temperature changes or large vibrations), and it would be possible to measure any pressure changes due to its deformation. By applying this sensor, it can be used as a position sensor (including a three-dimensional sensor) or an acceleration sensor, so that it could be applied to the control of the arms and legs of a robot, smart shoes, and the like. 

Dielectric Elastomer Sensor Capable of Measuring Large Deformation and Pressure

Balanced bending fatigue life for helical gear drives to enhance the power transmission capacity through novel rack cutters

Venous system disorders such as Orthostatic hypotension, deep vein thrombosis (DVT), and edema affect the lower limbs and are common causes of decreased work performance and quality of life. Solutions such as compression devices, rotation of staff, and regular breaks help improve these problems. Some active compression devices require air compression which needs a pump thus making them bulky. A cuff muscle device that uses a dielectric elastomer as a soft actuator and sensor is proposed to supplement the existing means of reducing the effects of these disorders. A physics-based model of the device is developed 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 to capture the pressure change experienced by the device under an applied voltage. The model is then validated in the normal frequency range of the device. This model may be used to predict the influence of different model parameters on the performance of the device before the fabrication process reducing the need for multiple prototyping. 

Physics-Based Modeling of Dielectric Elastomer Enabled Cuff Device

A Phenomenological Model for Bolt Loosening Characteristics in Bolted Joints Under Cyclic Loading

Venous system disorders such as Orthostatic hypotension, deep vein thrombosis (DVT), and edema affect the lower limbs and are common causes of decreased work performance and quality of life. Solutions such as compression devices, rotation of staff, and regular breaks help improve these problems. Some active compression devices require air compression which needs a pump thus making them bulky. A cuff muscle device that uses a dielectric elastomer as a soft actuator and sensor is proposed to supplement the existing means of reducing the effects of these disorders. A physics-based model of the device is developed 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 to capture the pressure change experienced by the device under an applied voltage. The model is then validated in the normal frequency range of the device. This model may be used to predict the influence of different model parameters on the performance of the device before the fabrication process reducing the need for multiple prototyping.

Wearable dielectric elastomer actuators (DEAs) have been greatly considered for development of biomedical devices. In particular, a DEA cuff device has the capability of minimizing venous system disorders that occur in the lower limbs such as orthostatic intolerance (OI) and deep-vein thrombosis which are a result of substantial blood pooling. Recent works have shown that DEAs could regulate and even enhance venous blood flow return. This wearable technology orders a new light, low-cost, compliant, and simple countermeasure which could be safely and comfortably worn that includes mobility. In addition, it may supplement or even provide an alternative solution to exercise and medication. This work presents the design, model, and characterization of the DEA cuff device design that is capable of generating significant pressure change. A rolled DEA strip was actuated over a simulated muscle-artery apparatus using a periodic voltage input, and fluid pressure change was directly observed. A force sensitive resistor sensor was used to achieve a more precise pressure measurement. Performance analysis was conducted through frequency response analysis. The results provide a framework for implementing dynamic modelling and control to allow various forms of actuation input.

Design, fabrication, and characterization of dielectric elastomer actuator enabled cuff compression device

Contact Fatigue Life Estimation for Asymmetric Helical Gear Drives

Variable magnetic field Hall and magneto- resistance measurements were carried out at 77K on thin HgCdTe samples of different thickness A simultaneous multi-carrier fitting of magneto resistance and Hall coefficient vs magnetic field data was used to extract the bulk and surface carrier information Studies have been conducted on both chemo-mechanically polished bare samples as well as the ones passivated with anodic oxide The bulk carrier concentration in very thin (< 30 mum) samples have been found to vary with thickness

R. Venkatraman

Papers

Design, fabrication, and characterization of dielectric elastomer actuator enabled cuff compression device

Contact Fatigue Life Estimation for Asymmetric Helical Gear Drives

Study on magneto-transport in thin HgCdTe crystals

Balanced bending fatigue life for helical gear drives to enhance the power transmission capacity through novel rack cutters

Physics-Based Modeling of Dielectric Elastomer Enabled Cuff Device