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Abstract Soft robots have revolutionized machine interactions with humans and the environment to enable safe operations. The fixed morphology of these soft robots dictates their mechanical performance, including strength and stiffness, which limits their task range and applications. Proposed here are modular, reconfigurable soft robots with the capabilities of changing their morphology and adjusting their stiffness to perform versatile object handling and planar or spatial operational tasks. The reconfiguration and tunable interconnectivity between the elemental soft, pneumatically driven actuation units is made possible through integrated permanent magnets with coils. The proposed concept of attaching/detaching actuators enables these robots to be easily rearranged in various configurations to change the morphology of the system. While the potential for these actuators allows for arbitrary reconfiguration through parallel or serial connection on their four sides, we demonstrate here a configuration called ManusBot. ManusBot is a hand-like structure with digits and palm capable of individual actuation. The capabilities of this system are demonstrated through specific examples of stiffness modulation, variable payload capacity, and structure forming for enhanced and versatile object manipulation and operations. The proposed modular, soft robotic system with interconnecting capabilities significantly expands the versatility of operational tasks as well as the adaptability of handling objects of various shapes, sizes, and weights using a single system.
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Directional Stiffness Modulation of Parallel Robots with Kinematic Redundancy and Variable Stiffness Joints
Parallel robots have been primarily investigated as po- tential mechanisms with stiffness modulation capabilities through the use of actuation redundancy to change internal preload. This paper investigates real-time stiffness modula- tion through the combined use of kinematic redundancy and variable stiffness actuators. A known notion of directional stiffness is used to guide the real-time geometric reconfig- uration of a parallel robot and command changes in joint- level stiffness. A weighted gradient-projection redundancy resolution approach is demonstrated for resolving kinematic redundancy while satisfying the desired directional stiffness and avoiding singularity and collision between the legs of a Gough/Stewart parallel robot with movable anchor points at its base and with variable stiffness actuators. A simulation study is carried out to delineate the effects of using kinematic redundancy with or without the use of variable stiffness ac- tuators. In addition, modulation of the entire stiffness matrix is demonstrated as an extension of the approach for modulating directional stiffness.
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- Award ID(s):
- 1734461
- PAR ID:
- 10097563
- Date Published:
- Journal Name:
- Journal of Mechanisms and Robotics
- ISSN:
- 1942-4302
- Page Range / eLocation ID:
- 1-14
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1115/1.4043685
