1,109 research outputs found
A Hybrid Adaptive Controller for Soft Robot Interchangeability
Soft robots have been leveraged in considerable areas like surgery,
rehabilitation, and bionics due to their softness, flexibility, and safety.
However, it is challenging to produce two same soft robots even with the same
mold and manufacturing process owing to the complexity of soft materials.
Meanwhile, widespread usage of a system requires the ability to fabricate
replaceable components, which is interchangeability. Due to the necessity of
this property, a hybrid adaptive controller is introduced to achieve
interchangeability from the perspective of control approaches. This method
utilizes an offline trained recurrent neural network controller to cope with
the nonlinear and delayed response from soft robots. Furthermore, an online
optimizing kinematics controller is applied to decrease the error caused by the
above neural network controller. Soft pneumatic robots with different
deformation properties but the same mold have been included for validation
experiments. In the experiments, the systems with different actuation
configurations and the different robots follow the desired trajectory with
errors of 0.040 and 0.030 compared with the working space length, respectively.
Such an adaptive controller also shows good performance on different control
frequencies and desired velocities. This controller endows soft robots with the
potential for wide application, and future work may include different offline
and online controllers. A weight parameter adjusting strategy may also be
proposed in the future.Comment: 8 pages, 9 figures, 4 table
Flexible Over-the-Tube Device for Soft-Tethered Colonoscopy
Soft-tethered colonoscopes were proposed for safe and effective colon navigation, yet the deployment of front-wheel actuated colonoscopes is hindered by contact interactions with the lumen along the entire soft tether. To mitigate this problem, this study introduces an over-the-tube flexible device aimed to assist colonoscope deployment. The device is composed of three pneumatically driven actuators devised to repeatedly perform a two-phase operation: (phase I) to advance along the tether up to a working position relatively close to the colonoscope’s tip; (phase II) to clamp and drag the tether forward, upon anchoring to colonic wall. This way, a distal tether portion is freed, thus reducing the aforementioned limitations and fostering effective front-wheel navigation. Considering anatomical/clinical constraints and a 2N resistive force, we designed and prototyped a system with an inner and outer diameter of 12 and 26 mm, respectively, a length of 91 mm, and operating pressures equal to 150, 50 and 15 kPa for clamping the tether, elongating the device and safely anchoring to the colonic wall, respectively. The device was successfully tested, achieving locomotion speeds up to 4.9 and 2.2 mm/s, and tether freeing rates up to 2.9 and 1.8 mm/s, in tabletop conditions and in a colon phantom, respectively
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