In Situ Reconfiguration of Assembling Pattern for Modular Continuum Robots

Modular continuum robots possess significant versatility across various scenarios;however,conventional assembling methods typically rely on linear connection between modules.This limitation can impede the robotic interaction capabilities,especially in specific engineering applications.Herein,inspired by the assembling pattern between the femur and tibia in a human knee,we proposed a multidirectional assembling strategy.This strategy encompasses linear,oblique,and orthogonal connections,allowing a two-module continuum robot to undergo in-situ reconfiguration into three distinct initial configurations.To anticipate the final configuration resulting from diverse assembling patterns,we employed the positional formulation finite element framework to establish a mechanical model,and the theoretical results reveal that our customizable strategy can offer an effective route for robotic interactions.We showcased diverse assembling patterns for coping with interaction requirements.The experimental results indicate that our modular continuum robot not only reconfigures its initial profile in situ but also enables on-demand regulation of the final configuration.These capabilities provide a foundation for the future development of modular continuum robots,enabling them to be adaptable to diverse environments,particularly in unstructured surroundings.

Mechanistic Analysis and Bio-inspired Applications for a Bidirectional Stiffness of a Water Snail Operculum

The water snail Pomacea canaliculata retracts the discoidal and multi-layered operculum to protect the soft body from being attacked by predators,and releases it when threats lifted.However,the duration of the operculum retraction is usually less than that of the operculum protraction.In this paper,we elucidate the biological compliant mechanism of the operculum.By using confocal laser scanning microscopy,we find that the operculum has compliant sandwiched layers between hard layers.The layered structure results in a compliant mechanism with a bidirectional stiffness for the locking and unlocking processes of the operculum.A mathematical model is derived to rationalize the bidirectional stiffness mechanism of the operculum.In addition,we carry out the experiments on the locking and unlocking processes.The experimental results show that the locking tension is about two-fifths of the unlocking tension of the operculum.Moreover,based on the mechanical properties of the operculum with the layered structure,we designed an operculum-inspired structure,which may have a variety of potential applications in combined driving patterns.

Dynamic modeling and beating phenomenon analysis of space robots with continuum manipulators

Space robotics has been used extensively in complex space missions. Rigid-manipulator space robots may suffer from rigid-body collisions with targets. This collision is likely to cause damage to the space robot and the target. To overcome such a problem, a novel ContinuumManipulator Space Robot(CMSR) for performing on-orbit servicing missions is proposed in this paper. Compared with rigid-manipulator space robots, CMSRs are able to perform compliant operations and avoid rigid-body collisions with a target. The CMSR consists of two kinds of flexible components, including solar arrays and continuum manipulators. The elastic vibrations of these flexible components disturb the position and attitude of CMSRs. The beating phenomenon introduced by the energy transfer among these flexible components can cause damage to solar arrays.The complicated dynamic coupling poses enormous challenges in dynamic modeling and vibration analysis. The dynamic model for CMSRs is derived and the mechanism of the beating phenomenon is analyzed in this paper. Simulation results show that an obvious beating phenomenon occurs and the amplitude of the solar arrays increases significantly when the natural frequencies of two kinds of flexible components are close. A method is provided to avoid the beating phenomenon.