Fluid‑actuation robotics on the rise

Most robots move like power tools because electric motors like to spin, gears like to stay stiff, and metal joints like to follow exact paths. A fluid-driven robot moves more like a bike brake line or a blood-pressure cuff, because pressure can push, flex, and absorb shocks at the same time. (nature.com) That softness is why fluid actuation keeps coming back in robotics papers even after decades of motor-driven machines. A 2025 review in *Robotica* said fluid-based actuation remains the dominant approach in soft robotics, where precise control of pressure and valves decides how well the machine performs. (cambridge.org) The trade is simple: rigid motors are easier to command, but soft actuators are better at surviving contact. A soft gripper can wrap around fruit or a bottle without crushing it, because the body itself deforms instead of forcing every motion through a hard linkage. (nature.com) The hard part is that a soft body is harder to measure than a rigid arm. Researchers at Nature Communications wrote in January 2024 that soft robots still need sensory feedback for higher-level decisions, because bending material does not tell a controller where it is unless the machine can sense pressure, shape, or deformation. (nature.com) That is the backdrop for Clone Robotics pushing “Myofiber” artificial muscles instead of the usual motor-and-gear stack. On its product pages, Clone says its android platform uses musculotendon units attached to anatomically accurate points on a skeleton, copying how animal muscles pull on bones rather than how factory robots rotate a gearbox. (clonerobotics.com) Clone’s bet is not just soft actuators by themselves. Founder and Chief Executive Officer Dhanush Radhakrishnan has described the whole idea as a one-to-one copy of human anatomy, with fluidic artificial muscles driving a musculoskeletal frame instead of bolting rotary motors onto simplified joints. (ceoinsider.io) That design choice changes what the embedded computer has to do. A motor robot often asks for a joint angle and reads back an encoder, but a fluid robot has to manage pumps, valves, line pressure, compliance, and the way one squishy movement can affect the next one. (cambridge.org) It also changes what “sensing” means. The January 2024 Nature paper showed that a fluidic robot can sometimes infer object size, shape, roughness, and stiffness just by measuring the fluid input needed to move, which means the pressure system can double as part of the robot’s sense of touch. (nature.com) Clone’s public demos and product descriptions lean hard into that human-body analogy. The company says its humanoid program uses a polymer skeleton with 206 bone analogues and water-powered artificial muscles, and outside coverage has described a compact 500-watt pump acting like a hydraulic vascular system for the body. (clonerobotics.com) (maginative.com) If this approach works, the payoff is not just smoother video clips. It is a robot arm that can absorb bumps, a hand that can vary grip without a giant force spike, and a body that is mechanically closer to humans in kitchens, hospitals, and hotel rooms where hard collisions are expensive. (nature.com) (ceoinsider.io) If it fails, it will probably fail on the boring parts that never show up first in a demo: leaks, valve timing, calibration drift, pump noise, and the problem of figuring out exactly where a compliant limb is at every millisecond. That is why the rise of fluid-actuation robotics is really a story about control systems and sensing catching up to a new kind of machine body. (cambridge.org) (nature.com)