Research On The Key Technology Of Fabrication Of The Biomimetic Gecko Micro Adhesion Array And The Flexible Tactile Sensor

The gecko adhesion has many advantages, such as the large adhesion force, adaptive to rough surface and materials, harmless to the contact surface, self-cleaning and durability. Biomimetic gecko adhesive arrays are suitable for adhesive structures of wall climb robots. In order to efficiently control the contact force during the attachment and detachment procedure between the robot and the wall surface, it is needed to integrate the adhesive arrays with the flexible tactile sensor.The most developed biomimetic gecko adhesive arrays are single layer structures of micro polymer arrays made by mold method. Without the tactile function, the biomimetic adhesive array could not effectively control the adhesive force. However, the gecko skin receptor could be sensible to mechanical stimuli. So, the main aim of this paper is the fabrication of biomimetic micro adhesive array integrated with tactile function. We analyzed the effect of fabrication parameters and established a viscosity polymer tube flow model. The hybrid integration of a flexible sensor is studied, and the flexibility of the three-dimensional force sensor is developed by using flexible PCB and flip chip assembly technology.We adopt the mold method to fabricate the micro polymer adhesive array after full investigation of the current fabrication methods. The silicon micro hole array made by ICP Bosch deep etch technology is used as template, and the polydimethylsiloxane (PDMS) is injected, hardened and demolded. Flexible adhesive array with large area is therefore obtained with good adhesive force. The fabrication processes is studied intensively. Firstly, the final rise velocity of bubbles is obtained by analyzing the movement formation of the bubbles. Then, the tube flow model of viscosity polymer is built. The relationship between the flow length and the flow time is established, and the expression of the ultimate setae length is also theoretically established. The model shows that it only needs milliseconds for the polymer to penetrate into the bottom of the hole under atmosphere pressure. The penetrating efficiency increases with the hole diameter. The theory is proved by experiments. The polymer properties suitable for fabrication of setae are identified. The tip shape of setae is successfully controlled by passivation of the holes. The methods of enhancing demolding effect are discussed. We succeed in demolding through KOH etching when the micro polymer adhesive array can not be directly demolded.Model building, simulation, and adhesive force tests are carried out for the setae array. Firstly, the adhesion model between the setae array and the random rough surface is built, and the relationship of the adhesion force with the separation, the roughness and the length of setae is analyzed in detail. The adhesive force under different conditions is experimentally studied using the adhesive force measurement device. The profile model is also analyzed since the experiment adhesive force is greater than the theoretic value on high roughness tardo surface. Lastly, the stability of micro polymer array is proved to be more than one year by experimental results.We explore the fabrication technology of the silicon setae array by using ICP Bosch etch and SF₆ isotropic etch. The silicon setae array with high aspect ratio and sharp tip could be applied to space wall climb robot.The hybrid integration technology of the flexible sensor is studied since the adhesive array needs tactile function. The flexibility of the three-dimensional force sensor is achieved by the flexible PCB and flip chip assemble technology. The E-shape diaphragm mechanical model is established, and the response to three-dimensional force of the E-shape diaphragm is obtained by the finite element and output signals analysis. Then the sensor cell is assembled after its fabrication and experimental calibration. Finally, we achieve the integration of the adhesive array with tactile array preliminarily, providing the adhesive array with tactile function for the wall climb robot.