Search

Your search keyword '"He, Qiguang"' showing total 181 results
Start Over Author "He, Qiguang"
181 results on '"He, Qiguang"'

11. Toward mechanical proprioception in autonomously reconfigurable kirigami-inspired mechanical systems.

Author

Jiao, Weijian, Shu, Hang, He, Qiguang, and Raney, Jordan R.

Subjects
PROPRIOCEPTION, ELECTRONIC equipment, INFORMATION processing
Abstract

Mechanical metamaterials have recently been exploited as an interesting platform for information storing, retrieval and processing, analogous to electronic devices. In this work, we describe the design and fabrication a two-dimensional (2D) multistable metamaterial consisting of building blocks that can be switched between two distinct stable phases, and which are capable of storing binary information analogous to digital bits. By changing the spatial distribution of the phases, we can achieve a variety of different configurations and tunable mechanical properties (both static and dynamic). Moreover, we demonstrate the ability to determine the phase distribution via simple probing of the dynamic properties, to which we refer as mechanical proprioception. Finally, as a simple demonstration of feasibility, we illustrate a strategy for building autonomous kirigami systems that can receive inputs from their environment. This work could bring new insights for the design of mechanical metamaterials with information processing and computing functionalities. This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

17. Antagonistic Pump With Multiple Pumping Modes for On-Demand Soft Robot Actuation and Control

Author

Zhou, Jianshu, Chen, Wei, Cao, Hanwen, He, Qiguang, and Liu, Yunhui

Abstract

Pneumatic soft robots are prized for their flexibility in achieving adaptable deformations and compliance adjustments. However, the conventional pumps used in these systems often rely on simplistic, sensorless, and on–off control mechanisms, which limit the potential of these robots. Drawing inspiration from the intricate functionality of the natural heart-pumping mechanism, we present an innovative and versatile pump that integrates an antagonistic pumping mechanism with a reinforcement-learning-powered control strategy. The antagonistic pump features dual chambers for expansion and deflation, valve-controlled interconnections, and distributed pressure sensors. This dedicated architecture enables a nuanced air exchange logic and pumping sequence, thereby facilitating a wide range of pneumatic actuation possibilities for pneumatic soft robots. Our pressure control method leverages the structural capabilities and degrees of freedom inherent in the pump, enhancing pumping efficiency and precision. Diverging from the traditional controllers, it autonomously evaluates the properties of unknown connected loads and dynamically adjusts pumping actions accordingly. Consequently, the pump provides multiple pumping modes, including load perception, rapid inflation, dual-load control, adaptive pumping across positive and negative pressure ranges, fine-tuning, and instantaneous pressure switching. Moreover, by iteratively executing the pumping cycle, the pump can extend its output pressure limits. We have successfully built and tested a prototype pump, validating its ability to achieve a broad range of pressures with precise and robust control. These results underscore the pump's potential to actuate diverse soft robots through multimode pumping, offering a pioneering solution for universal soft robot actuation and control.

Published
2024
Full Text
View/download PDF

26. Genome-Wide Identification and Expression Profile Analysis of the Phenylalanine Ammonia-Lyase Gene Family in Hevea brasiliensis.

Author

Liu, Hui, He, Qiguang, Hu, Yiyu, Lu, Ruilin, Wu, Shuang, Feng, Chengtian, Yuan, Kun, and Wang, Zhenhui

Subjects
*GENE expression, *HEVEA, *GENE families, *POWDERY mildew diseases, *PHENYLALANINE, *SALICYLIC acid
Abstract

The majority of the world's natural rubber comes from the rubber tree (Hevea brasiliensis). As a key enzyme for synthesizing phenylpropanoid compounds, phenylalanine ammonia-lyase (PAL) has a critical role in plant satisfactory growth and environmental adaptation. To clarify the characteristics of rubber tree PAL family genes, a genome-wide characterization of rubber tree PALs was conducted in this study. Eight PAL genes (HbPAL1-HbPAL8), which spread over chromosomes 3, 7, 8, 10, 12, 13, 14, 16, and 18, were found to be present in the genome of H. brasiliensis. Phylogenetic analysis classified HbPALs into groups I and II, and the group I HbPALs (HbPAL1-HbPAL6) displayed similar conserved motif compositions and gene architectures. Tissue expression patterns of HbPALs quantified by quantitative real-time PCR (qPCR) proved that distinct HbPALs exhibited varying tissue expression patterns. The HbPAL promoters contained a plethora of cis-acting elements that responded to hormones and stress, and the qPCR analysis demonstrated that abiotic stressors like cold, drought, salt, and H2O2-induced oxidative stress, as well as hormones like salicylic acid, abscisic acid, ethylene, and methyl jasmonate, controlled the expression of HbPALs. The majority of HbPALs were also regulated by powdery mildew, anthracnose, and Corynespora leaf fall disease infection. In addition, HbPAL1, HbPAL4, and HbPAL7 were significantly up-regulated in the bark of tapping panel dryness rubber trees relative to that of healthy trees. Our results provide a thorough comprehension of the characteristics of HbPAL genes and set the groundwork for further investigation of the biological functions of HbPALs in rubber trees. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

30. Bioinspired liquid crystal elastomer (LCE) based soft actuators with multimodal actuation

Author

He, Qiguang

Subjects
Mechanical engineering, Robotics, Materials Science, Actuators, Artificial muscles, Liquid crystal elastomers, Soft robotics
Abstract

Inspired by the biology, soft robots have drawn tremendous attention due to its large and continuous deformation, friendly human-machine interaction, large number of degrees of freedom (DOFs), capability of absorbing energy. They have been explored in broad applications ranging from dexterous soft gripper to the novel assistive devices. In the recent decade, numerous soft actuating materials and deformable structures have been developed to construct soft robots, including hydrogels, shape memory polymers (SMPs), dielectric elastomer actuators (DEAs), fluid elastomer actuators (FEAs) and magnetic actuators. However, those materials and structures have well-known limitations such as slow actuation speed, irreversibility, high voltage input and bulky controlling systems. Liquid crystal elastomers (LCEs), as newly emerging soft actuating materials, exhibit large and reversible deformation and versatile actuation modes. Based on the molecular structure, LCE can be viewed as a combination of liquid crystal molecules and polymer networks. When the LCE is heated above the critical temperature, it can generate large deformation because of the nematic-isotropic phase transition. However, in terms of the practical use of LCE, a few challenges exist such as lack of programmable operation and slow responsive speed for LCEs, which need to be addressed.In this dissertation, we first integrate flexible heating wire into LCE tube, forming electrically controlled soft tubular actuator. By selectively applying low electrical voltage, this soft tubular actuator can exhibit multiple actuation modes, such as different directional bending and homogeneous contraction. The LCE soft tubular actuator can also be integrated to construct untethered robot that can execute multiple functionalities. To address the slow responsive speed of LCE based soft actuator, we embed microfluidic channel into LCE, forming vascular LCE soft actuator. Through alternatively injecting hot and cold fluid into its internal fluidic channel, the vascular LCE soft actuator can generate fast actuation as well as recovery. In addition, by introducing the disulfide bonds into the LCE materials, the newly obtained vascular LCE based soft actuator has shown repairability and recyclability. Finally, we use electrospinning technique to fabricate LCE microfiber that can be actuated by NIR light. We demonstrate that the electrospun LCE fiber can be easily integrated to micro-robotic system and machine as artificial muscle fiber.

Published
2021

43. Polymer nanofiber reinforced double network gel composites: strong, tough and transparent

Author

He, Qiguang

Subjects
Materials Science, Nanotechnology, Composite, Electrospinning, Hydrogel, Nanofiber
Abstract

Double network gel is well known for its extraordinarily high toughness and stretchability. However, compared to natural rubber and many soft biological tissues such as articular cartilage and tendon, both strength and stiffness of double network gel are significantly lower, which greatly limits its further applications. In this article, to improve mechanical properties of double network gel, we embed a small percentage of aligned electrospun polymer nanofibers into double network gel matrix to make a sandwich-like double network gel composite. Mechanical tests conducted by us show that polymer nanofiber reinforced double network gel composite have much higher strength and stiffness, while maintaining its good transparency.

Published
2016

Catalog

Books, media, physical & digital resources
See catalog results