Soft Robotics: Materials, Actuation, Modeling, and Control - A Comprehensive Review

Soft robotics replaces the rigid links and discrete joints of conventional manipulators with compliant materials whose stiffness approaches that of biological tissue, allowing a robot to adapt its shape to unfamiliar environments and to interact safely with fragile objects and humans. This compliance, however, gives a soft robot an effectively infinite-dimensional configuration space, so the modeling and control tools developed for rigid robots cannot be applied directly. This paper reviews the field through four closely linked aspects. Materials and actuation are discussed first, covering silicone elastomers, stimuli-responsive smart materials, fiber-reinforced composites, fabrication techniques, and pneumatic, tendon-driven, smart-material, and variable-stiffness actuators. Modeling and control are then examined together, ranging from the low-order piecewise constant curvature model to Cosserat rod, finite element, and data-driven models, and from model-based feedback to model-free, learning-based, and energy-aware control. The paper concludes with applications in grippers, medical and wearable devices, and locomotion, and outlines the open challenges of embedded sensing, actuator durability, and energy efficiency together with directions for future research.