Unlike regular robots that move using rigid motors and joints, soft robots are made from flexible materials such as soft rubber and move using special actuators – components that act like artificial muscles to produce physical motion. While their flexibility makes them ideal for delicate or adaptive tasks, controlling soft robots has always been a challenge because their shape changes in unpredictable ways. Real-world environments are often complicated and full of unexpected disturbances, and even small changes in conditions – like a shift in weight, a gust of wind or a minor hardware fault – can throw off their movements.
In a study titled ‘A general soft robotic controller inspired by neuronal structural and plastic synapses that adapts to diverse arms, tasks, and perturbations’, recently published in Science Advances, the researchers describe how they developed a new AI control system that allows soft robots to adapt across diverse tasks and disturbances. The study takes inspiration from the way the human brain learns and adapts and was built on extensive research in learning-based robotic control, embodied intelligence, soft robotics and meta-learning.
The system uses two complementary sets of “synapses” – connections that adjust how the robot moves – working in tandem. The first set, known as “structural synapses”, is trained offline on a variety of foundational movements, such as bending or extending a soft arm smoothly. These form the robot’s built-in skills and provide a strong, stable foundation. The second set, called “plastic synapses”, continually updates online as the robot operates, fine-tuning the arm’s behaviour to respond to what is happening in the moment. A built-in stability measure acts like a safeguard, so even as the robot adjusts during online adaptation, its behaviour remains smooth and controlled.
“This new AI control system is one of the first general soft-robot controllers that can achieve all three key aspects needed for soft robots to be used in society and various industries. It can apply what it learned offline across different tasks, adapt instantly to new conditions and remain stable throughout - all within one control framework,” said Associate Professor Zhiqiang Tang, who was a Postdoctoral Associate at M3S and at NUS when he carried out the research, is the first and co-corresponding author of the paper, and is now Associate Professor at Southeast University (SEU China).
“Soft robots hold immense potential to take on tasks that conventional machines simply cannot, but true adoption requires control systems that are both highly capable and reliably safe. By combining structural learning with real-time adaptiveness, we’ve created a system that can handle the complexity of soft materials in unpredictable environments. It’s a step closer to a future where versatile soft robots can operate safely and intelligently alongside people - in clinics, factories, or everyday lives,” said Professor Daniela Rus, Co-lead Principal Investigator at M3S, Director - Computer Science and Artificial Intelligence Laboratory (CSAIL) at MIT, and co-corresponding author of the paper.
The system supports multiple task types, enabling soft robotic arms to execute trajectory tracking, object placement and whole-body shape regulation within one unified approach. The method also generalizes across different soft-arm platforms, demonstrating cross-platform applicability.
The system was tested and validated on two physical platforms – a cable-driven soft arm and a shape-memory-alloy–actuated soft arm – and delivered impressive results. It achieved a 44–55 % reduction in tracking error under heavy disturbances, over 92 % shape accuracy under payload changes, airflow disturbances and actuator failures, and stable performance even when up to half of the actuators failed.
“This work redefines what’s possible in soft robotics. We’ve shifted the paradigm from task-specific tuning and capabilities toward a truly generalizable framework with human-like intelligence. It is a breakthrough that opens the door to scalable, intelligent soft machines capable of operating in real-world environments,” said Professor Cecilia Laschi, Principal Investigator at M3S, Provost’s Chair Professor, Department of Mechanical Engineering at the College of Design and Engineering and Director of the Advanced Robotics Centre at NUS, and co-corresponding author of the paper.
This breakthrough opens doors for more robust soft robotic systems to develop manufacturing, logistics, inspection and medical robotics without the need for constant reprogramming – reducing downtime and costs. In healthcare, assistive and rehabilitation devices can automatically tailor their movements to a patient’s changing strength or posture, while wearable or medical soft robots can respond more sensitively to individual needs, improving safety and patient outcomes.
The researchers plan to extend this technology to robotic systems or components that can operate at higher speeds and more complex environments, with potential applications in assistive robotics, medical devices and industrial soft manipulators, as well as integration into real-world autonomous systems.
The research conducted at SMART was supported by the National Research Foundation Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) program.