Fluidic Elastomer Actuators (FEAs) are lightweight, flexible systems widely used in robotics and biomedical devices. However, real-time monitoring of their performance remains a challenge. To address this, researchers have developed a Dielectric Elastomer Sensor (DES) capable of measuring pressure and vibrations in these deformable structures. This innovation enhances actuator efficiency and expands potential applications in robotics, automotive systems, and infrastructure monitoring.
Image Credit: Shibaura Institute of Technology (SIT)
Fluidic Elastomer Actuators (FEAs) are pressurized tubes or membranes that can be easily rearranged into complex mechanical devices. They have gained significant attention for their lightweight, flexible nature, making them ideal for robotics and biomedical devices. However, the accurate measurement of their dynamic response and rearrangement is challenging because traditional sensors, such as piezoelectric accelerometers and piezoresistive sensors, are not suitable for freeform surfaces like domed roofs or complex shapes. Their rigid metallic casings restrict large deformations and affect the FEA’s performance.
Additionally, the accurate measurement of dynamic responses in FEAs plays an important role in automobile designing. While designing new cars with high efficiency and safety, the measurement of vibration and static pressure on the pressurized tires with an inflatable structure are inevitable. These measurements not only reveal the performance of the car but also their structural health.
Motivated by this gap in technology, a team of scientists led by Professor Naoki Hosoya from Shibaura Institute of Technology (SIT), Japan, explored Dielectric Elastomer Sensor (DES) to address this challenge.
The team consisted of Mr. Haruyuki Kurata from SIT, Japan, Dr. Ardi Wiranata from the University of Gadjah Mada, Professor Shingo Maeda from the Institute of Science Tokyo, Dr. David Garcia Cava from The University of Edinburgh, and Dr. Francesco Giorgio-Serchi from The University of Edinburgh. This study explored how DESs can be used to measure the pressure and vibration response on soft fluidic structures.
Our study explores how DES can be effectively implemented for real-time state estimation and control of soft fluidic actuators.
Naoki Hosoya, Professor, Shibaura Institute of Technology
To understand how this sensor works, a team of scientists fabricated a capacitive-type DES using polydimethylsiloxane (PDMS) and carbon nanotubes. The sensor was then tested to measure the vibration response of soft fluidic systems under pneumatic actuation and was capable of measuring vibrations up to 100 Hz.
The device measured vibration and static pressure by capturing the change in capacitance. When the DES was subjected to an external force, leading to a deformation, the capacitance increased. The team also found that DES exhibited a linear response to vibration amplitude, with its sensitivity increasing as static pressure decreased.
The mass and rigidity of the conventional sensors like piezoelectric accelerometers and piezoresistive sensors strongly influence the dynamic characteristics of the underlying inflatable structures, likely hindering the nominal operation of the actuator.
Naoki Hosoya, Professor, Shibaura Institute of Technology
Unlike piezoresistive sensors, DES is flexible and can withstand large deformative rearrangements, making them ideal for real-time monitoring of FEAs.
These findings highlight the potential of DES as a valuable sensing device for soft robotics and health monitoring. The ability of DES to function in complex, deformative environments allows it to set a new standard for applications in robotics, biomedical devices, and large-scale infrastructure.
“These results indicate that lightweight, highly stretchable DESs can be conveniently used as embedded units within complex fluidic networks, aiding in monitoring of this type of actuators,” concluded Prof. Hosoya.
Journal Reference:
Kurata, H., et al. (2025) Dynamic response characterization of soft fluidic actuators via dielectric elastomer sensors. Measurement. doi.org/10.1016/j.measurement.2024.116616