Soft robots often struggle to generate strong, fast movements because their flexible materials cannot store and release energy as efficiently as rigid mechanical systems. Scientists at the University of Bristol have developed a new approach that allows soft robotic structures to harness stored elastic energy in a controlled way, enabling rapid and powerful motion without sacrificing the safety and adaptability that make soft robotics valuable. Their work demonstrates how a simple change in how soft materials are arranged can dramatically improve performance across a wide range of applications.
The team created a soft robotic arm that uses a combination of elastic bands and carefully designed geometry to store energy and release it on demand. By preloading the structure with tension, the robot can move much more quickly than traditional soft devices, which typically rely on slow pneumatic or hydraulic actuation. The researchers showed that the arm could snap forward with enough force to launch objects, demonstrating a level of speed and power rarely seen in soft robots. They also found that the system could be tuned to produce different motion profiles by adjusting the placement and strength of the elastic elements.
The approach is inspired by biological systems that use stored elastic energy to achieve rapid movement. Many animals rely on tendons or specialized tissues to amplify muscle power, allowing them to jump, strike or escape predators with remarkable speed. The Bristol team applied similar principles to soft robotics, showing that flexible materials can be engineered to behave more like biological springs. Their prototype demonstrated that soft robots can achieve high performance without becoming rigid or losing their ability to interact safely with humans and delicate environments.
The researchers believe the technique could be applied to medical devices and wearable technologies. Soft robots capable of fast, precise motion could improve surgical tools, assistive devices or rehabilitation systems by providing gentle yet responsive movement. The method could also help create safer robots for manufacturing, where soft structures reduce injury risk while still delivering useful force. Because the design relies on simple materials and straightforward fabrication, it may be easier to scale and adapt than more complex soft robotic systems.
Future work will focus on refining the technique, exploring new material combinations and integrating sensing and control systems to make the robots more autonomous. The team sees the discovery as a step toward soft machines that combine biological agility with engineering reliability, opening new possibilities for devices that must operate safely around people while still performing demanding tasks.
Article from the University of Bristol: Scientists discover smart way to supercharge soft robotics and better support rehabilitation patients
Abstract in Advanced Functional Materials: Electrocapillary Modulated Interfacial Tension Amplifies Liquid Metal Transduction
