Biorobotics and Foldable Intelligence Laboratory

分类： Paper

学术论文 | Vertebraic Soft Robotic Joint Design With Twisting and Antagonism

https://doi.org/10.1109/LRA.2021.3131701

Abstract

The soft robotic manipulators attract extensive interest of researchers due to its conformity to the unstructured environment, safe-interaction with human and fragile objects. The movement of the soft manipulator often include elongation, contraction, 2-DOF rotations due to the parallelly arranged fluidic-actuated linear soft actuators. Few design achieves bending and twisting around the longitudinal axis concurrently, thus hindering the implementation of such manipulator in scenarios requiring local position adjustment. Here, we proposed a soft robotic joint with a vertebra in the center of the tilt-arranged soft origami actuators, which enables twisting motion in addition to the rotation X and Y. Moreover, the tilted actuator configuration and the vertebra formed an antagonism pair, which endowed the soft joint with improved payload and stiffness variability. Due to the vertebra and the antagonism it provided, the joint prototype generated 22.6 N, 27.4 N force and 1.7 Nm torque in respective rotations with a light weight of 90.3 g; The resist force of the joint increased about 70% when inflated to 90 kPa; the RMSE between the actual and the desired output in a range of frequencies reduced considerably compared to the soft robotic joints without vertebra. A dedicated model was proposed and verified, obtaining the relationship between the input pressure and the output position/posture of the joint, providing a mapping model for the control loop.

04/17/2025
学术论文 | A Six Degrees-of-Freedom Soft Robotic Joint With Tilt-Arranged Origami Actuator

https://doi.org/10.1115/1.4054731

Abstract

Soft manipulators attract increasing interest in robotic applications involving the unstructured environment and human-robot interaction. The majority of the soft manipulator with fluidic actuators consists of joints that are constructed by parallel actuators, achieving rotation and extension. The inability to output twisting and lateral translations concurrently in the joints hinders the applications of such soft manipulators that require dexterous manipulation. In this work, the tilted actuator soft robotic (TASR) joint with 6DOF mobility, i.e., three rotations and three translations, is studied by kinematic modeling, simulations, and experiments. The 6DOF joint has a lightweight (74.8 g) due to the implementation of soft origami actuators (SOA) and soft-rigid structure. The investigation on the characteristics of the 4-joint assembly recorded maximum in-plane translations over a 70 mm range (70% of its diameter), axial translation over 50 mm (27% of its length), and rotations over 120 deg in all three directions. Kinematic modeling and FEM simulations have been carried out on the mechanical behaviors of the joint. A soft manipulator has been produced to verify the practicality of the joint in constructing the soft robotic systems, with the repetitive accuracy and movements demonstrated in an application scenario. The 6DOF TASR joint showed the potential to be implemented in constructing dexterous and lightweight soft robotic systems, with mass-production readiness.

04/17/2025
学术论文 | Deformation of the Miura-ori patterned sheet

https://doi.org/10.1016/j.ijmecsci.2015.05.009

Abstract

The Miura-ori pattern possesses intriguing mechanical features, namely, the one Degree Of Freedom mobility, auxetic in-plane behavior and energy absorption capability, for applications such as core to sandwich structure, shock absorber, airless tire, etc. To realize the folding mechanism of Miura-ori, in this paper a Miura-ori patterned sheet was made from copolymer Elvaloy by compression molding, and then its deformation behavior was investigated experimentally and by using finite element analysis. The intrinsic mechanical properties of Elvaloy were obtained by tensile and four-point-bending tests, respectively, and subsequently used in the finite element (FE) simulation. For utilizing the sheet in all the principal directions, three types of tests were conducted: out-of-plane compression, three-point-bending and in-plane compressions. FE simulations using Abaqus/Explicit were carried out to analyze the deformations of the patterned sheet under the same loading as that in the tests. The simulation results were then compared with the tests, which show good agreements. Based on the simulation results, the deformation patterns of the patterned sheet under different loading conditions were examined, as well as the energy absorption capacity.

04/17/2025
学术论文 | Origami-Patterned Rigidification for Soft Robotic Bifurcation

https://doi.org/10.1002/aisy.202300767

Abstract

The fluid-transportation functions based on the volume-regulating behavior of the chamber-like organs inspire the development of artificial organs. Due to the intrinsic compliance of soft robotics for biomimicking purposes and the volume-regulation capability of the 3D origami patterns, the soft robots with origami patterns show promising potential in such research. However, the folding deformation of the origami facets cannot be straightforwardly implemented as the actuation or the body movement, and the predetermined movements of the pattern limit the appropriate functions for specific applications. In this work, an origami-patterned rigidification (OPR) method is proposed for applying rigid origami mechanisms (herein, the cuboctahedron origami ball) to the chamber-like structure of soft robots. The motion of the soft robot is programmed by purposefully rigidified the soft chamber following the pattern. The resultant OPR structures are granted with functions corresponding to the predetermined motion of the pattern, and the expanded movements through the bifurcation brought by the soft–rigid characteristics. The concept, design, and fabrication of the OPR robot are presented. By analyzing the deformation of the soft creases, the kinematic models of the predetermined and expanded degrees of freedom are presented and verified by experiments. The extended functions of two OPR robots are demonstrated.

04/16/2025
学术论文 | Dynamics-Oriented Underwater Mechanoreception Interface for Simultaneous Flow and Contact Perception

https://doi.org/10.1002/aisy.202400492

Abstract

The lack of a sufficient and efficient way to simultaneously perceive general underwater mechanical stimuli, physical contact, and fluidic flow has been a bottleneck for many aquatic applications. To address this challenge, dynamics-oriented underwater mechanoreceptor interface (DOUMI), a bioinspired mechanoreception system that realizes simultaneous contact and flow perception using a single receptor, is introduced. This receptor, response-elevated-and-expanded hair-like tactile mechanoreceptor (REEM), is inspired by the mechanoreceptive mechanism of aquatic arthropods. REEM combines structural features from different mechanoreceptive sensilla, enabling it to capture a wide range of stimulus dynamics. Under different stimuli, REEM encodes stimuli dynamics as its oscillations with distinct spectral attributes. Those oscillations are efficiently transferred through mechanical processes and imaging, enabling vision-based extraction and further analysis. Therefore, by evaluating the oscillation dynamics with tailored wavelet-based indices, DOUMI can distinguish between contact- and flow-induced oscillations at each receptor unit with 90.5% accuracy. Furthermore, DOUMI provides comprehensive 2D mechanoreception with a scalable array of REEMs, delivering capabilities like stimuli spatiotemporal visualization, flow trend detection, and scenario classification with an accuracy of 99.5%. With its robustness and operational efficiency in underwater environments, DOUMI can be easily adapted to existing applications using common materials and hardware, establishing a new, streamlined paradigm for underwater general mechanoreception.

04/16/2025
学术论文 | Single Pump-Valve Pneumatic Actuation With Continuous Flow Rate Control for Soft Robots

https://doi.org/10.1109/LRA.2025.3531147

Abstract

Pneumatic actuated soft robots attract increasing interest of the researchers due to the availability and simplicity in actuation. The soft robots driven by soft pneumatic actuators (SPAs) of various active volumes demand pneumatic systems with various range of flow rate. However, the usually bulky and hard-to-carry pneumatic actuation systems restrict the portability, and the air pumps provide constant flow rate which constrained the applications such as soft wearable devices and scenarios require fine flow rate control. In this work, aiming for simplicity, high portability, continuous and small flow rate regulation, the pneumatic actuation system consists of identical integrated soft robotic drivers (iSoRD) modules is proposed, obtaining positive and negative pressure output (−53∼83 kPa) in each module using one-pump-one-valve (4-way/2-position solenoid) design. With the check valves installed and the modular design, pressure holding and flow independence are achieved in each pneumatic branch. The heat generation (37.7 °C) and power consumption (2.95 W per-channel) are measure to verify usability. The continuous and fine flow rate regulation (15 mL/s) is achieved by applying the PID controller on the pump motor, which shows superior performance in signal tracking in comparison with the non-continuous Bang-Bang and Varia-speed Bang-Bang algorithms. With the same control, the iSoRD system reduces the error by 37.5% in comparison to our previous two-pump system. The portability, versatility in wearing, practicality and adaptivity of the system are validated by driving three wearable soft robots, a small gripper and a pollination device. Comparing with the existing, the iSoRD is capable of fine flow rate regulation in both negative and positive pressure range with low power consumption, portability and versatility, which will benefit the pneumatic soft robotic systems with broadened application potential.

04/08/2025
学术论文 | Otariidae-Inspired Soft-Robotic Supernumerary Flippers by Fabric Kirigami and Origami

https://doi.org/10.1109/TMECH.2020.3045476

Abstract:

Wearable robotic devices are receiving rapidly growing attentions for human-centered scenarios from medical, rehabilitation, to industrial applications. Supernumerary robotic limbs have been widely investigated for the augmentation of human limb functions, both as fingers and manipulator arms. Soft robotics offers an alternative approach to conventional motor-driven robot limbs toward safer and lighter systems, while pioneering soft supernumerary limbs are strongly limited in payload and dexterity by the soft robotic design approach, as well as the fabrication techniques. In this article, we proposed a wearable supernumerary soft robot for the human forearm, inspired by the fore flippers of otariids (eared seals). A flat flipper design was adopted, differing from the finger- or arm-shaped state-of-the-art works, with multiple soft actuators embedded as different joints for manipulation dexterity. The soft actuators were designed following origami (paper folding) patterns, reinforced by kirigami (paper cutting) fabrics. With this new approach, the proposed soft flipper incorporated eight independent muscles, achieving over 20 times payload to self-weight ratio, while weighing less than 500 g. The versatility, dexterity, and payload capability were experimentally demonstrated using a fabricated prototype with proprietary actuation and control. This article demonstrates the feasibility and unique advantages of origami + kirigami soft robots as a new approach to strong, dexterous, and yet safe and lightweight wearable robotic devices.

04/03/2025
学术论文 | 3D Printed Multi-Cavity Soft Actuator with Integrated Motion and Sensing Functionalities via Bio-Inspired Interweaving Foldable Endomysium

https://doi.org/10.1002/advs.202409060

Abstract

The human muscle bundle generates versatile movements with synchronous neurosensory, enabling human to undertake complex tasks, which inspires researches into functional integration of motions and sensing in actuators for robots. Although soft actuators have developed diverse motion capabilities utilizing the inherent compliance, the simultaneous-sensing approaches typically involve adding sensing components or embedding certain-signal-field substrates, resulting in structural complexity and discrepant deformations between the actuation parts with high-dimensional motions and the sensing parts with heterogeneous stiffnesses. Inspired by the muscle-bundle multifiber mechanism, a multicavity functional integration (McFI) approach is proposed for soft pneumatic actuators to simultaneously realize multidimensional motions and sensing by separating and coordinating active and passive cavities. A bio-inspired interweaving foldable endomysium (BIFE) is introduced to construct and reinforce the multicavity chamber with optimized purposive foldability, enabling 3D printing single-material fabrication. Performing elongation, contraction, and bidirectional bending, the McFI actuator senses its spatial position, orientation, and axial force, based on the kinematic and sensing models built on multi-cavity pressures. Two McFI-actuator-driven robots are built: a soft crawling robot with path reconstruction and a narrow-maneuverable soft gripper with object exteroception, validating the practicality in stand-alone use of the actuator and the potential for intelligent soft robotic innovation of the McFI approach.

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04/03/2025