63 research outputs found
Modeling and Direct Adaptive Robust Control of Flexible Cable-Actuated Systems
Cable-actuated systems provide an effective method for precise motion transmission over various distances in many robotic systems. In general, the use of cables has many potential advantages such as high-speed manipulation, larger payloads, larger range of motion, access to remote locations and applications in hazardous environments. However, cable flexibility inevitably causes vibrations and poses a concern in high-bandwidth, high-precision applications
Separable Tendon-Driven Robotic Manipulator with a Long, Flexible, Passive Proximal Section
This work tackles practical issues which arise when using a tendon-driven
robotic manipulator (TDRM) with a long, flexible, passive proximal section in
medical applications. Tendon-driven devices are preferred in medicine for their
improved outcomes via minimally invasive procedures, but TDRMs come with unique
challenges such as sterilization and reuse, simultaneous control of tendons,
hysteresis in the tendon-sheath mechanism, and unmodeled effects of the
proximal section shape. A separable TDRM which overcomes difficulties in
actuation and sterilization is introduced, in which the body containing the
electronics is reusable and the remainder is disposable. An open-loop redundant
controller which resolves the redundancy in the kinematics is developed. Simple
linear hysteresis compensation and re-tension compensation based on the
physical properties of the device are proposed. The controller and compensation
methods are evaluated on a testbed for a straight proximal section, a curved
proximal section at various static angles, and a proximal section which
dynamically changes angles; and overall, distal tip error was reduced
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