A Twist in Motion: Improving Continuum Robots

Continuum robots have a common issue: when one part moves, others often follow unintentionally. This is known as motion coupling, and it makes controlling these robots tricky. To tackle this problem, a new type of robot has been designed. It's called the Variable-Pitch Flexible-Screw-Driven Continuum Robot (FSDCR). This robot has a clever way to keep the sections moving independently. Imagine a series of vertebrae, like in a spine, arranged in a line. These are connected to flexible screws that drive their movement. The special thing about these screws is that they can change their pitch, or the distance between the threads. This allows the robot to apply forces and constraints more accurately. The flexible screws work together in a unique way. They balance the driving force and torque within each section by twisting in opposite directions. This is called antagonistic torsional actuation. It helps the robot achieve motion decoupling, meaning each section can move independently. Experiments were done to compare this new robot with one that has constant-pitch screws. The results showed that the variable-pitch FSDCR was much more accurate. It had an average error of just 0. 79 mm, which is a big improvement over the constant-pitch robot. Not only is it more accurate, but the variable-pitch FSDCR can also carry more weight. Its load capacity is up to 129. 09% better than the constant-pitch robot. Even when moving faster, the motion coupling error remains low, at just 0. 32 mm. To show off its abilities, a three-section FSDCR was built. It demonstrated impressive load capacity and motion flexibility. This new design opens up exciting possibilities for continuum robots.