Progress on gecko-inspired micro/nano-adhesion arrays

Gecko’s excellent adhesion ability is thought to derive from van der Waals force generated between the millions of keratinous hairs/setae and the contact surface. Fabricating highly gecko-inspired foot-hair becomes one of the key technologies to realize the three-dimensional-obstacle-free motion of robot. Researchers have fabricated various gecko-like foot-hair arrays which have leaning, large end, and hierarchical structures. Those significant works are summarized and suggestions for future work are proposed in this paper.     

Locomotion behavior and dynamics of geckos freely moving on the ceiling

To understand the mechanical interactions when geckos move on ceiling and to obtain an inspiration on the controlling strategy of gecko-like robot, we measured the ceiling reaction force (CRF) of freely moving geckos on ceiling substrate by a 3-dimensional force measuring array and simultaneously recorded the locomotion behaviors by a high speed camera. CRF and the preload force (F_P) generated by the geckos were obtained and the functions and the differences between forces generated by fore- and hind- feet were discussed. The results showed that the speed of gecko moving on the ceiling was 0.17–0.48 m/s, all of the fore- and hind-legs pulled toward the body center. When geckos attached on the ceiling incipiently, the feet generated a very small incipient F_P and this fine F_P could bring about enough adhesive normal force and tangential force to make the gecko moving on ceiling safely .The F_P of the fore-feet is larger than that of the hind-feet. The lateral CRF of the fore-feet is almost the same as that of the hind-feet’s. The fore-aft CRF generated by the fore-feet directed to the motion direction and drove their locomotion, but the force generated by the hind-feet directed against the motion direction. The normal CRF of fore- and hind-feet accounted for 73.4% and 60.6% of the body weight respectively. Measurements show that the fore-aft CRF is obviously lager than the lateral and normal CRF and plays a major role in promoting the fore-feet, while the hind-feet of the main role are to provide a smooth movement. The results indicate that due to the differences of the locomotion function of each foot between different surfaces, the gecko can freely move on ceiling surfaces, which inspires the structure designing, gait planning and control developing for gecko-like robot.     

蛤蚧端脑皮质加厚区的细胞形态及纤维联系

采用Golgi法对蛤蚧皮质加厚区的细胞形态和纤维联系进行研究。结果表明:1.皮质加厚区有圆形、星形、梨形、梭形和不规则形等细胞,主要以梭形和不规则形细胞为主;2.皮质加厚区存在环状细胞丛簇结构,这种结构与前背侧室嵴嘴外侧区的基本相同;3.皮质加厚区与前背侧嵴嘴外侧区、尾外侧区和纹状体(Pth-ADVRrl-ADVRcl-Str)存在着广泛的纤维联系。     

仿壁虎粘附阵列与粗糙表面间粘附仿真分析

根据线性梁理论，针对仿壁虎粘附阵列与服从高斯分布的粗糙表面，分别建立了在动态粘附接触与动态脱离过程中二者相互作用力模型．基于合理的参数选择，讨论了该作用力与二者间的间距、预压力及夹角等因素的关系，并得到仿真结果．这一研究为仿壁虎纳米粘附阵列的设计提供理论参考．     

大壁虎线粒体12S rRNA基因片段的两种单倍型

通过测定大壁虎５个个体的线粒体１２Ｓ ｒＲＮＡ基因片段序列,发现大壁虎明显地分为两种单倍型。结合染色体组型上的微小差异,这样的种内差异是否可能达到亚种级水平,还有待于进一步研究。     

Behavior and dynamics of gecko＇s locomotion： The effects of moving directions on a vertical surface

The study of the movement behavior of geckos on a vertical surface, including the measurement and recording of the reaction forces as they move in different directions, plays an important role in understanding the mechanics of the animals’ locomotion. This study provides inspiration for the design of a control system for a bionics robot. The three-dimensional reaction forces of vertical surface-climbing geckos (Gekko gecko) were measured using a three-dimensional force-sensors-array. The behavior of gecko as it moved on a vertical surface was recorded with a high speed camera at 215 fps and the function of each foot of a gecko are discussed in this paper. The results showed that the gecko increased its velocity of movement mainly by increasing the stride frequency in the upward, downward and leftward direction and that the speed had no significant relationship to the attachment and detachment times. The feet above the center-of-mass play a key role in supporting the body, driving locomotion and balancing overturning etc. The movement behavior and foot function of geckos change correspondingly for different conditions, which results in safe and effective free vertical locomotion. This research will be helpful in designing gecko-like robots including the selection of gait planning and its control.     

Angular observation of joints of geckos moving on horizontal and vertical surfaces

Because of their outstanding climbing and motor coordination ability, geckos have provided the basis for a peculiar bionic model leading to the development of a geckorobot. A three-dimensional locomotion observation system was constructed to measure angular orientations of joints while geckos trotted (337.1 mm/s) and walked (66.7 mm/s) on horizontal surfaces, and trotted (241.5mm/s) and walked (30.6mm/s) on vertical surfaces. Moving over horizontal surfaces, the joints rotated more quickly the greater the s...     

蛤蚧前背侧室嵴嘴外侧区的投射研究

本文运用HRP顺、逆行追踪技术,对蛤蚧（Gekko gecko)前背侧室嵴（ADVR）嘴外侧区纤维联系进行了研究。结果表明,ADVR嘴外侧区核心部的传入纤维来自双侧丘脑园核（Rt)前、中部的腹外侧区;ADVR嘴外侧区与尾部在室周带中有广泛分布的环路存在;ADVR嘴外侧区核心部－皮层加厚区环路是联系两条视觉通路的桥梁。     

A stereotaxic method and apparatus for the <Emphasis Type="Italic">Gekko gecko</Emphasis>

To study the modulation mechanism of the middle brain of the Gekko to the locomotion, we introduced a stereotaxic method first in literature and developed an apparatus suitable for Gekko gecko, the biggest wall and ceiling climber in nature. We defined the bregma and nasal points as reference points, selected the bilateral infraorbital margin and top point of the maxillary tooth for locating and fixing, and set up the line passing through the bregma and paralleling to a line connecting the bilateral infraorbital margin as x axis. Then, we defined a horizontal plane in the stereotaxic instrument, passing through x axis and the certain point which is 4.8 mm exactly above the nasal point, as the XOY plane; the sagittal plane, i.e. the YOZplane, is the plane which is perpendicular to x axis and passes through the bregma; the plane, i.e. the XOZ plane, which passes through x axis and is perpendicular to the horizontal plane is the coronal plane. We designed a set of head holder which includes three parts： bilateral infraorbital margin clamps, a gecko adaptor holding the rostral side of the upper jaw. The allocation and operation of the head holder is accurate and simple, and the device is low in cost and compatible with standard stereotaxic instrument.     

Research progress in gecko locomotion and biomimetic gecko-robots

Geckos are known for their excellent ability to climb walls and run on ceilings. Previous studies of the gecko's locomotive and adhesive mechanisms, its neuro-sensory and neuro-modulatory systems, its fabrication of artificial setae array, and other related developments, have inspired further research on gecko-based and gecko-like robots. Key research findings in this area are reviewed in the present paper.