Wearable PZT Sensor
For any soft wearable device the information about the surrounding environment and interactions is an important performance aspect. A sensor design becomes challenging when the target component has a non-uniform, agile, high resolution, and soft surface. Recent developments in wearable sensor technology have made it possible to embed piezoelectric element (PZT) based sensors, conductive fabrics, electro-active polymers and other families of stretchable and flexible sensors into soft silicone.
We have developed PZT based sensors for wearable applications owing to their low cost, high sensitivity, high customization and low hysteresis properties. Multiple PZT sensors can be distributed over the actuation surface to provide multiple points for sensing. Piezoelectric ceramics are known to be highly sensitive to normal forces applied and can be embedded into silicone substrates [1]. Our sensors can have multiple pixels of PZT elements discretely distributed over a surface area in the form of grid. The PZT sensing elements are connected using fl exible circuit tracks manufactured by laser cutting the copper-plated kapton (polyamide) material. The construction is then embedded inside silicone material for additional support and electrical insulation.
The novelty in our design includes customizability, high density, parallel information gathering and the possibility of active feedback control using sensed information [2]. The presented prototype’s mechanical and functional capacities are promising for applications in biomedical systems where soft, wearable and high precision sensors are needed these sensors and their applications are highly desired in human-robot interaction, biomedical robotics and biomimetic robotics in order to provide effective sensory feedback. The sensor applications can also be extended further wherever the similar performance is necessary.
Figure 1. Sensor manufacturing process of the PZT sensor prototype with 2 x 2mm2 PZT elements (A),(B),(C),(D). Silicone integrated 8×2 PZT sensor matrix demonstrating flexibility and distribution capabilities (E).
References :
[1] Acer, Merve, et al. “Development and characterization of silicone embedded distributed pie-zoelectric sensors for contact detection.” Smart Materials and Structures 24.7 (2015) : 075030.
[2] Sonar, Harshal Arun, and Jamie Paik. “Soft pneumatic actuator skin with piezoelectric sensors for vibrotactile feedback.” Frontiers in Robotics and AI 2 (2015) : 38.
Manual for sensor design and electronic signal conditioning :