Seoul National University's College of Engineering (Dean Cha Guk-heon) announced on the 8th that Professor Park Yong-Rae's team at the Department of Mechanical Engineering has developed soft sensor technology that can be easily varied and detect motion in various ways. Professor Park Yong-Rae said "This technology will enable the development of wearable technology that can remotely operate robots much more intuitively and easily."

 

With a thickness of 6mm and a length of 7cm, this single sensor can be attached to joints like the wrist, enabling remote transmission of various commands to robots or computers based on body movements only.

 

Recently, as augmented reality (AR) and virtual reality (VR) technologies have been commercialized and received public attention, there has been active development of interfaces to more effectively convey information between humans and robots (or machines). The most commonly used method for intuitive information transmission for robot operation is motion.

 

In other words, detecting human movements at every moment and allowing robots to perform necessary tasks through them. Yet, existing sensors mainly detect only single variations, so for multiple tasks, many sensors had to be used, making the system inevitably complex. However, if one sensor can easily detect various types of movements and variations, it becomes possible for a robot to easily understand and perform complex tasks.

 

To address this issue, Professor Park Yong-Rae's team has developed a multifunctional soft sensor capable of detecting not only individual deformation modes such as tension, bending, and compression with a single sensor, but also deformation that combines two or more modes simultaneously.

 

Therefore, using this technology, it is possible to transmit a wide range of information to robots using a small number of sensors. Also, since it is made of flexible materials, it can easily detect various transformations without interfering with human movement when attached to the human body, which is a significant advantage in implementing wearable interfaces.

 

The sensor developed in this study is made of silicone rubber material that can easily stretch or bend. Inside the rod-shaped structure, there are small hollow channels (microchannels), which are filled with a transparent ion solution that conducts electricity. Additionally, thin conductive fabric is attached to the outer wall of the sensor.

 

When the sensor is stretched, bent, or pressed, it is possible to measure changes in the light transmittance and electrical conductivity of the ion solution, as well as changes in the electrical resistance of the conductive fabric, depending on the type of transformation. By using combinations of these signals, it is possible to simultaneously detect various types of deformations. Since these three sensing mechanisms share the structure organically, it is structurally simple and manufacturing process is also simple.

 

The research team has also created a wearable interface using this sensor, demonstrating that devices such as robot arms and drones can be easily operated remotely. Additionally, it was shown that when this sensor is combined with a soft robot, even the robot's movements can be accurately detected.

 

The results of this study were published online on December 16 in the world-class international academic journal Science Robotics. This research was conducted with the support of the Soft Robotics Technology Leading Research Center Project and the Global Ph.D. Fellowship Program of the Ministry of Science and ICT.

 

▲ A multifunctional soft sensor that implements sensor elements based on three different principles (optical components, ion solution, conductive fabric) into a single sensor structure.

▲ Example of remote control of a robot arm using a wearable wristband embedded with a soft sensor.

▲ Soft robot capable of stretching, contracting, and bending, equipped with soft sensors.