Soft ceramic sensors for robotics

Empa

New research could pave the way for smarter and more responsive robots

Spotted: Humans have long been captivated by robots, and although the humanoid machines of sci-fi fiction are yet to enter the mainstream, robotics technology is already boosting efficiencies across various industries, from manufacturing to farming.

However, a key limitation of current robotic designs hinders their adaptability: the lack of embodied sensation. Robots, often constructed from rigid materials, can’t replicate the same rich sensory experience humans use to understand the world. To help bridge this gap, scientists led by Dr Frank Clemens at the Swiss Federal Laboratories for Materials Science and Technology (Empa) are developing soft sensor materials based on ceramics, which would allow robots to “feel”.

Ceramics are non-metallic materials made up of a collection of loose particles, and their final properties will change depending on the specific internal composition. While ceramics are traditionally rigid, embedding ceramic fillers within a thermoplastic matrix makes the final composite material soft and flexible – which is what the Empa researchers have achieved. The researchers tested various fillers in the matrix, and by carefully controlling the composition, it’s possible to create soft ceramic materials with the desirable mechanical properties.

Crucially, depending on the structure, ceramics can also conduct electricity and as they’re exposed to stimuli like pressure or temperature shifts, the distance between ceramic particles changes, along with the sensor’s electrical conductivity. Using different fillers, it’s possible to create soft sensors that respond to heat, pressure, strain, chemical gases, and humidity.

According to Dr Clemens, using ferroelectric ceramic fillers makes it possible to build self-powered sensors “because the electrical energy is given by the ceramic filler itself”. This innovative polymer composite offers a new material in robotics hardware, enabling robots to combine durability with advanced sensing capabilities.

While the material can respond to various stimuli, accurately interpreting these signals in real-world applications remains challenging. Because of this, Dr Clemens explained to Springwise “Therefore, I think the next step is to develop selective sensors, which only react to one stimulus”. With scientists from ETH Zurich and the University of Tokyo, the Empa team combined soft piezoresistive (pressure) sensors with artificial muscles to create a bio-hybrid robot that recognises whether or not the muscle is contracted.

Written By: Joshua Solomon and Matilda Cox