ABI's Biomimetics Lab, where work on electric charge has helped create groundbreaking inventions.
Biomimetics involves drawing inspiration from nature to develop new technologies. Living organisms and natural phenomena have certain behaviours and properties which let them exist in harmony with the surrounding environment.
By understanding these natural processes, we are developing technologies to venture into new territories.
Our research revolves around combining electric charge with soft polymer to make stretch sensor for capturing gestures and body motion, actuators for soft robots, or energy converters that can transform human body motion into electricity.
Our research has led to the creation of several spin-out companies:
We need you!
We are constantly looking for talented students for our numerous projects. We currently have one fully funded positions which we urgently need to fill:
- A Ph.D. position in the area power conversion for wearable devices (more info)
Research area 1: Soft sensors and haptics
Bringing motion capture under water
Gesture recognition and sensor-based motion capture have been growing areas of research for the past few decades. With project ADRIATIC (Advancing Diver Robot Interaction Capabilities) the Biomimetics Laboratory is taking this research underwater. The project sees the development of dive gloves with integrated wearable sensors and electronics. As participating divers perform gestures, a machine learning algorithm assesses the hand motion and recognizes these in real-time. They are then interpreted as commands or messages and transmitted acoustically through the water to a buddy diver or robot.
The video bellow shows an underwater trial, where Biomimetics Lab glove is being used to communicate and command an autonomous underwater vehicle (AUV) developed by the LABUST Lab from the University of Zagreb, Croatia. As the diver performs a gesture, it is recognized and communicated to the AUV as a movement instruction.
Derek and Chris are working on this project and are supported by the Office of Naval Research (ONR) Global, through project ADRIATIC.
Compression sensors for the manipulation of fragile objects
The tactile sense is one of the most important ways to get information from the outside world. Take the example of babies that only use their tactile sense to find their mother in the early time after birth. In contrast, most robotic manipulators are devoid of tactile sense, which can lead to injuries or damages when manipulating soft tissues or delicate objects.
The aim of this project is to develop soft proprioceptive feedback for robotic manipulators, in order to give robots the ability to sense their environment and interact safely with it. One of the key elements of the research project consists in the development of a very sensitive and compliant capacitive touch sensor, based on structured silicone and interdigitated electrodes (IDEs). We are also studying soft sensor topologies that combines thin capacitive sensors on passive paddings to increase the sensitivity. Our compressive sensors are able to measure small forces (0-10N) while conforming to the target object, and we are working on position location, multi-touch detection, as well as shear force measurement. All of these technologies can be included in a soft compression skin that can be included to robotic manipulators to measure the grasping force, identify the contact points when picking up an object, and detect possible slippage. Other applications include clinical measurement mats to exercise the feet of patients suffering from diabetic foot ulcer.
Smart sensing algorithms to extract more information from soft sensors
Soft sensors give information on how much they are being stretched or compressed by changing their capacitance? It would be extremely useful if, in addition from the amount of force or deformation applied to the sensor, we were also be able to extract location information, i.e. which part of the sensor is deformed. Instead of splitting the sensor in a multitude of sub-sensors and multiply the number of wires and electrical connections, we will rely on smart algorithm based on machine learning. The concept is simple: we send an excitation signal with a broad frequency range in the sensor, and depending on the frequency spectrum of the measured signal, we can identify not only the amplitude of the deformation, but where it has been applied. All this without any physical modification to the sensor: we rely on computing power to extract more information from simple sensors.
Consider a soft compression sensor mounted on a robotic gripper designed to handle fragile objects such as fruits or berries (figure below). From a single pair of wires, the algorithm enables to measure how much pressure is applied to the object, and where along the gripper the fruit is located.
Literature on the subject:
Adding haptic feedback to a smart glove
With the rising popularity of virtual reality, comes to a need for more natural and intuitive human machine-interaction methods, one such method is using a motion capturing smart glove. However, when the user is trying to interact with a virtual object with his/her hand, using a smart glove alone can be bland without any feedback and stimulation.
This project aims to develop a clip-on vibrotactile feedback system for the fingertips to improve the experience of human-machine interaction when using a motion capturing glove. Vibrotactile feedback is produced by a piezoelectric actuator. By altering the vibration frequency, intensity and pattern the device can communicate various haptic information to the user such as surface texture and the clicking sensation when pressing a button.
Research area 2: Soft actuators
Rubber in space
Dielectric Elastomer Transducers (DETs) integrated into inflatable structures can form the basis for soft, low mass robots. These can be packed into very small spaces and then simply deployed via inflation. Being soft also makes them safer, allows them to change their shape easily to adapt to different environments and different orientations. These attributes, combined with the high power density of DETs, make active inflatables ideal for space robotics. We have constructed prototypes capable of multi-directional movement using only electrical actuation, and combined these with electro-adhesive technology to allow controllable gripping of nearby objects or surfaces. Our first design, MIDA, was presented at the EuroEAP conference of 2019. This, and our other prototypes have potential applications in the fields of on-orbit repairs, structural health monitoring (and control) of inflatable space structures, and lightweight planetary/asteroid rovers.
These prototypes face many challenges however, before they would be ready for operation in space. Low Earth Orbit (LEO, from 100 – 2000 km above the earth) is a hostile environment for any material. Any robot in LEO must contend with extreme heat (and cold), intense electromagnetic radiation, plasma, and reactive oxygen gas amongst other problems. In order to protect our soft robots, we have been developing a space-grade sunscreen, designed to shield the DETs from this harsh environment through a combination of low-Z (light metal) oxide nanoparticles suspended in a vacuum-stable silicone grease. Ground-based testing in oxygen plasma facilities is used to perform accelerated space-aging tests, simulating months to years of orbit in a matter of days. This will allow us to test how long our robots will be able to survive in space.
This project is laying the groundwork for the production of inflatable DET space robots. Though in its early stages, the development of smart-material lightweight space robots has the potential to change the ways we can explore space.
Torturing brain cells to understand traumatic brain injury
Because our soft actuators are compact, integrated to a transparent membrane and fast, they are perfect to make deformable bioreactors that can submit cells to mechanical deformation.
Why do we want to stretch cells? Because this allows to perform in-vitro experiments that are more similar to what happens in-vivo. If you think about it most of our cells are constantly submitted to mechanical deformation (muscles, cardiac cells, intestine), or force (bones), which a culture in a Petri dish cannot recreate. For example, we are using the rapid stretching rate of our actuators to submit brain cells to a mechanical insult. This enables to recreate traumatic brain injury in vitro and study gene expression or scar formation.
Rubbery logic is a new type of computing using soft materials – just polymer and carbon - and no conventional electronics required. This ability is enabled by the dielectric elastomer switch (DES) – a rubbery switch that turns electric charge on and off with stretch. The DES can directly control dielectric elastomer actuators (DEA), and networks of coupled DEA and DES can build up computing networks.
This addresses a challenge in soft robotics, which is integrating intelligence in a soft system. Conventional electronics are rigid and dense, not a good fit for soft and stretchy structures. Rubbery logic, on the other hand, can be part of the soft system, allowing entirely soft and autonomous robotics.
We have demonstrated all the fundamental Boolean logic gates and basic memory functions in the lab, and have produced some soft robotic demonstrators that use these circuits for different abilities.
The videos below show a couple examples of rubbery logic and DEA in action: Trevor crawls like a caterpillar and Jule flaps its wings like a dragonfly – both cyclic motions enabled by a dielectric elastomer oscillator (DEO) circuit. These electronics-free robots are fed a DC charge, and the DEO generates an oscillating voltage, which drives the actuators in a rhythmic pattern to allow the robots to crawl and to flap. Another video shows a gripper that is controlled by user input to two DES push buttons and a DE NAND gate control circuit mounted inside the device.
Katie is working on this project and her PhD was funded by grants from the US Army Research, Development & Engineering Command International Technology Center-Pacific (ITC-PAC). Katie is now commercialising the technology she developed during her Ph.D. via the Biomimetics lab’s spin out company PowerOn.
Literature on the subject:
Research area 3: Generating electricity from rubber
Periodic movements, such as the motion of the body, or the waves on the ocean can be used to cyclically deform soft generators that can convert mechanical energy into electrical energy. The Biomimetics lab has pioneered the self-priming circuit, an intelligent charge management circuit that enables to boost a small amount of priming charges to higher energy levels. We have even demonstrated how this circuit can be integrated to the soft generators, hence minimising the number of electrical components. In our most recent design, we have demonstrated that the generator can be primed from “nothing” (or to be more precise by ambient electromagnetic noise), thus removing the need for priming charges.
We are currently looking for a Ph.D. candidate to push this project further and tackle the challenge of converting the high voltage charges produced by the soft generators into a low voltage that can be used to power consumer electronics or physiological sensors.
Literature on the subject:
Our Spin-out companies
- Switzerland: EMPA and EPFL
- UK: Bristol Robotics Lab
- US: US Army Research Lab