Design and Feasibility Tests of a Gas-driven Bionic Flytrap Soft Robot

The research of bionic soft robot is a complex system engineering, including soft matrix material, soft actuator, soft sensor and bionic control system. Unlike most animals, plants cannot move in whole voluntarily. However, for the purpose of energy and nutrition, various parts of the plant body also carry out various movements, which vary from millisecond to hour on a large time scale. As a result, Plants are considered a source of inspiration for innovative engineering solutions, and a growing number of researchers are investigating the mechanisms of plant movement and biomimetic research. In this paper, the biological morphology, microstructure and movement mechanism of Venus flytrap leaf were studied and analyzed, and a bionic flytrap grassland machine with chamber design was designed and manufactured. Firstly, according to the research report on the biological morphology, microstructure and movement mechanism of Venus flytrap, the idea of chamber design was determined. Based on this observation, we reconstructed the leaf model and bionic structure of Venus flytrap by reverse modeling. Based on the principle of turgor pressure deformation, the chamber design rules of bionic Venus flytrap blade were formulated and optimized with silica gel as the bulk material. The flow channel design of Venus flytrap blade was studied and explored. Finally, the bionic Venus flytrap leaf was made by 3D printing technology and silica gel casting process, and the two bionic leaves were clamped at a certain opening Angle. The bending performance of bionic flytrap blade and the flytrap closure experiment were studied by air pressure excitation. The experimental results show that the bionic Venus flytrap blade can complete bending and closing experiments, and the bionic Venus flytrap can complete the whole capturing process within 5s. The leaf opening Angle of the bionic Venus flytrap reaches 80 degrees, which fits well with the real Venus flytrap blade and meets the design requirements and bionic goals. Apparently, this study is the first to design the chamber of the bionic flytrap leaf, formulate rules, and study the possibility of its deformation. It provides a new idea for the study of the movement and deformation of plant leaves, and expands the application of bionic robots, especially the robot solutions for plant types.

How to Surpass the Deep-Sea Glass Sponges Mechanically

The biomimetic design of engineering structures is based on biological structures with excellent mechanical properties, which are the result of billions of years of evolution. However, current biomimetic structures, such as ordered lattice materials, are still inferior to many biological materials in terms of structural complexity and mechanical properties. For example, the structure of \textit{Euplectella aspergillum}, a type of deep-sea glass sponge, is an eye-catching source of inspiration for biomimetic design; however, guided by scientific theory, how to engineer structures surpassing the mechanical properties of \textit{E. aspergillum} remains an unsolved problem. The lattice structure of the skeleton of \textit{E. aspergillum} consists of vertically, horizontally, and diagonally oriented struts, which provide superior strength and flexural resistance compared with the conventional square lattice structure. Herein, the structure of \textit{E. aspergillum} was investigated in detail, and by using the theory of elasticity, a lattice structure inspired by the bionic structure was proposed. The mechanical properties of the sponge-inspired lattice structure surpassed the sponge structure under a variety of loading conditions, and the excellent performance of this configuration was verified experimentally. The proposed lattice structure can greatly improve the mechanical properties of engineering structures, and it improves strength without much redundancy of material. This study achieved the first surpassing of the mechanical properties of an existing sponge-mimicking design. This design can be applied to lattice structures, truss systems, and metamaterial cells.

Structural Design, Simulation and Experiment of Quadruped Robot

This paper carried out a series of designs, simulations and implementations by using the physical-like mechanism of a bionic quadruped robot dog as a vehicle. Through an investigation of the walking mechanisms of quadrupeds, a bionic structure is proposed that is capable of omnidirectional movements and smooth motions. Furthermore, the kinematic and inverse kinematic solutions based on the DH method are explored to lay the foundation for the gait algorithm. Afterward, a classical compound pendulum equation is applied as the foot-end trajectory and inverse kinematic solutions are combined to complete the gait planning. With appropriate foot–ground contact modeling, MATLAB and ADAMS are used to simulate the dynamic behavior and the diagonal trot gait of the quadruped robot. Finally, the physical prototype is constructed, designed and debugged, and its performance is measured through real-world experiments. Results show that the quadruped robot is able to balance itself during trot motion, for both its pitch and roll attitude. The goal of this work is to provide an affordable yet comprehensive platform for novice researchers in the field to study the dynamics, contact modeling, gait planning and attitude control of quadruped robots.

Fabrication and Performance of Graphene Flexible Pressure Sensor with Micro/Nano Structure

Laser-induced graphene (LIG) has been widely used in flexible sensors due to its excellent mechanical properties and high conductivity. In this paper, a flexible pressure sensor prepared by bionic micro/nanostructure design and LIG mass fraction regulation is reported. First, prepared LIG and conductive carbon paste (CCP) solutions were mixed to obtain a conductive polymer. After the taro leaf structure was etched on the surface of the aluminum alloy plate by Nd:YAG laser processing, the conductive polymer was evenly coated on the template. Pressure sensors were packaged with a stencil transfer printing combined with an Ecoflex flexible substrate. Finally, the effects of different laser flux and the proportion of LIG in the composite on the sensitivity of the sensor are discussed. The results show that when the laser flux is 71.66 J·cm−2 and the mass fraction of LIG is 5%, the sensor has the best response characteristics, with a response time and a recovery time of 86 ms and 101 ms, respectively, with a sensitivity of 1.2 kPa−1 over a pressure range of 0–6 kPa, and stability of 650 cycle tests. The LIG/CCP sensor with a bionic structure demonstrates its potential in wearable devices.

Effects of Pine Bark Extract on Physicochemical Properties and Biological Activity of Active Chitosan Film by Bionic Structure of Dragonfly Wing

Bionic and active films based on chitosan were developed with the bionic structure of dragonfly wings incorporating pine bark extract (PBE). Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, and water vapor permeability were measured. Antioxidant activity of the films was characterized by DPPH free radical scavenging activity. The interaction between chitosan and PBE was explored by attenuated total reflectance Fourier transform infrared spectrometry, X-ray diffraction, and differential scanning calorimetry. The results indicated that the addition of PBE gave rise to the films greater opacity, redness, and darker appearance. Compared with pure chitosan film, the thickness, opacity, mechanical properties, and oxidation resistance of the bionic chitosan–PBE film increased, and the water vapor permeability decreased. The films based on chitosan incorporated PBE and with the bionic structure of dragonfly wings can potentially be applied to food packaging.