Wearable integrated piezoelectric film sensor with tensioning, bending, shearing and twisting detection functions for human motion recognition (original) (raw)
Related papers
Flexible unimodal strain sensors for human motion detection and differentiation
npj Flexible Electronics
Multiple strain sensors are required to identify individual forces/stresses on human joints and recognize how they work together in order to determine the motion’s direction and trajectory. However, current sensors cannot detect and differentiate the individual forces/stresses and their contributions to the motion from the sensors’ electrical signals. To address this critical issue, we propose a concept of unimodal tension, bend, shear, and twist strain sensors with piezoelectric poly L-lactic acid films. We then construct an integrated unimodal sensor (i-US) using the unimodal sensors and prove that the i-US can detect and differentiate individual strain modes, such as tensioning, bending, shearing, and twisting in complex motion. To demonstrate the potential impact of unimodal sensors, we design a sleeve and a glove with the i-US that can capture wrist motions and finger movements. Therefore, we expect unimodal strain sensors to provide a turning point in developing motion recogni...
A novel application method for wearable bend sensors
Applied Sciences in …, 2009
Bend sensors fundamental characteristic is to furnish an electrical resistance value related to the angle they are bent. This feature can be successfully exploited to realize wearable systems capable to measure human static and dynamic postures. In particular some efforts have been made to determine finger joint movements of human hands and it has been demonstrated the feasibility of using the so called data glove system as a goniometric device. The repeatability of such system is quite good for general purposes but it is still not sufficient for specific applications (for instance in virtual surgery). So here we introduce a novel application method of bend sensors and demonstrate how it can be useful to improve the system repeatability.
Recent progress in flexible piezoelectric devices toward human-machine interactions
Human-machine interactions are becoming increasingly required for intelligent sensing and effective manipulation. Recent developments in flexible piezoelectric sensors with short response time and high force-electric interconversion efficiency present a tendency toward facilitating diverse human-machine interactive applications. Here, we review the development of flexible piezoelectric human-machine interactions in the context of robotic control, the Internet of Things, sports coaching and acoustic therapeutics. The synthesis of unique materials, the distinct design of device structures, the typical applications of piezoelectric human-machine interactions and the integration of cutting-edge technologies are elaborated in detail based on recent research. Finally, we highlight the current challenges and directions for the development of piezoelectric human-machine interactions for more advanced application scenarios.
Evaluating Strain Sensor Performance for Motion Analysis
Investigation on the more suitable technologies to register human body movements in 3D space with great spatial accuracy is a very challenging task, because a wide range of applications are concerned, from registration of post-stroke rehabilitation or sports performance, to monitoring of movement of disabled or elderly people, etc. In this paper the possibilities offered by piezoresistive bend sensors applied as wearable devices, integrated on body garments, have been explored. Piezoresistive sensors can be usefully adopted to recover human joint bend angles for body movement tracking. Due to their pliability, sensitivity and cheapness, they could be a valid alternative to movement analysis systems based on optoelectronic devices or inertial electronic sensors. This paper suggests a new approach to model their electrical behavior during bending and extension movements, in order to predict their real-time performance during different kinds of applications.
Flexible Multifunctional Sensors for Wearable and Robotic Applications
Advanced Materials Technologies, 2019
where there is a need for high sensitivity, accuracy, flexibility, and low cost. For such applications, the sensors must be compatible with large-area processing techniques and readily integrated into flexible devices, and effort in this area has accelerated the range of potential applications. [1] Empowering robots and skins with high resolution, high sensitivity, and rapid response sensing capabilities is significant to a broad range of applications including wearable healthcare devices, human-machine interacting robots such as service robots for the elderly [2,3] and electronic skin (e-skin) applied on or in the body that provide an unprecedented level of diagnostic and monitoring capabilities. [3,4] Flexible multifunctional sensors are essential components of e-skin to allow biomedical prostheses and robots to naturally interact with humans and the environment. The design and development of future e-skins have attracted significant interest in recent years, in particular an emphasis on being able to mimic the mechanically compliant yet highly sensitive properties of human skin, [4,5] multifunctional and simultaneous sensing, [6-8] and mechanical self-healing. [9] It is suggested that the modern multifunctional e-skins have great potential in non-invasive, high-fidelity, and continuous radial artery pulse wave monitoring. [4] They can also be used in future mobile health monitoring and remote diagnostics in cardiovascular medicine. [10] Figure 1 outlines examples of the multifunctional sensing needs and stimuli. This can include pressure, strain, or shear sensing using piezoelectric or piezoresistive effects or monitoring responsive color changes due to mechanochromic effects, or using photonics or liquid crystals. Temperature can also be monitored, for example, by using pyroelectric or thermochromic effects. Chemical sensing can also use piezoelectric effects, for example, by monitoring mass changes using resonance. The pressure generated by normal touch, object manipulation, and human body circulation are often distributed in lowpressure regimes (<10 kPa) and medium-pressure regimes (10-100 kPa). [11] Piezoelectric pressure sensors, which develop an electric charge in response to a mechanical load, have been widely and successfully used for pressure distribution measurement. Applications include prostheses (<1 kPa), [12] diagnostics This review provides an overview of the current state-of-the-art of the emerging field of flexible multifunctional sensors for wearable and robotic applications. In these application sectors, there is a demand for high sensitivity, accuracy, reproducibility, mechanical flexibility, and low cost. The ability to empower robots and future electronic skin (e-skin) with high resolution, high sensitivity, and rapid response sensing capabilities is of interest to a broad range of applications including wearable healthcare devices, biomedical prosthesis, and human-machine interacting robots such as service robots for the elderly and electronic skin to provide a range of diagnostic and monitoring capabilities. A range of sensory mechanisms is examined including piezoelectric, pyroelectric, piezoresistive, and there is particular emphasis on hybrid sensors that provide multifunctional sensing capability. As an alternative to the physical sensors described above, optical sensors have the potential to be used as a robot or e-skin; this includes sensory color changes using photonic crystals, liquid crystals, and mechanochromic effects. Potential future areas of research are discussed and the challenge for these exciting materials is to enhance their integration into wearables and robotic applications.
There is a growing demand for flexible and soft electronic devices. In particular, stretchable, skin-mountable, and wearable strain sensors are needed for several potential applications including personalized health-monitoring, human motion detection, human-machine interfaces, soft robotics, and so forth. This Feature Article presents recent advancements in the development of flexible and stretchable strain sensors. The article shows that highly stretchable strain sensors are successfully being developed by new mechanisms such as disconnection between overlapped nanomaterials, crack propagation in thin films, and tunneling effect, different from traditional strain sensing mechanisms. Strain sensing performances of recently reported strain sensors are comprehensively studied and discussed, showing that appropriate choice of composite structures as well as suitable interaction between functional nanomaterials and polymers are essential for the high performance strain sensing. Next, simulation results of piezoresistivity of stretchable strain sensors by computational models are reported. Finally, potential applications of flexible strain sensors are described. This survey reveals that flexible, skin-mountable, and wearable strain sensors have potential in diverse applications while several grand challenges have to be still overcome.
Soft Science, 2022
Whereas piezoelectric pressure sensors (PPSs) have been applied in the monitoring of human body movement and physiological parameters, they show inherent limitations in wearable applications, including toxicity, degradation, and brittleness. In this study, we develop safe, stable, and mechanically flexible composite thin films consisting of polyvinylidene fluoride (PVDF), BaTiO3 nanoparticles (BTO-NPs), and textured aluminum nitride (AlN) thin film for the demonstration of wearable PPS with enhanced output performance and biocompatibility. The PPS made of BTO-NP-embedded-PVDF and AlN film on Cu foil is attached to different parts of human body to measure different output voltages depending on the physiological and physical stimulus. The simple bending (from breathing, chewing, and swallowing), joint motions (at wrist, elbow, and finger), and low- (from eyeball movement) and high-pressure applications (by squat, lunge, and walking) are measured. Our PVDF+BTO-NP/AlN-PPS (PBA-PPS) device has the potential for personal safety, healthcare, and activity monitoring applications with easy wearability.