Research On Flexible Tactile Sensor Array For Tactile And Slip Detection In Intelligent Robotic Grasping

Supported by the National Natural Science Foundation of China(Project No.51575485)and the Natural Science Foundation of Zhejiang Province(Grant No.LY16E050002),this dissertation studies the flexible tactile sensor array for intelligent robotic hands and carry out three-dimensional force distribution detection and slip determination methods in the process of intelligent robot hand's grasping.Firstly,a flexible tactile sensor array based on the piezoresistive conductive rubber is designed,which includes layered structures such as force-transmitting bumps,conductive rubber and patterned electrode array substrate.The three-dimensional force and slip detection method of this flexible tactile sensor array is expounded.Secondly,according to the structural design of the flexible tactile sensor array,the micro-manufacturing process of the sensor array is developed,and the prototype of the sensor array is completed.The array scanning multi-channel signal acquisition system for this sensor array is designed and manufactured.The detection performance of the flexible tactile sensor array is tested and analyzed.Then,the finite element simulation modeling and experimental test in the grasping process are carried out for the two commonly used grasping modes(fingertip pinch and palm grip)of intelligent robot hands,and study the distribution of three-dimensional force and analyze the causes.Finally,the three-dimensional force distribution simulation and experimental test analysis of different shapes of objects are carried out,and the wavelet transformation method is used to judge the object slip during the grasping process.In Chapter 1,the background and significance of this dissertation is introduced.Then,the current research situation is expatiated in detail,including tactile detection system for intelligent robot hands,tactile sensors and tactile detection technology in the process of intelligent robot object grasping.By comparing the shortcomings in the research,the main research content and framework of the thesis are determined.In Chapter 2,by analyzing the electromechanical body structure and grasping action of the intelligent robot hand,the goals and requirements of the tactile sensor array are proposed,and then the structural design of the flexible tactile sensor array is carried out.The sensor array is arranged in a 3x3 array,and including a force transfer bump layer,a conductive rubber layer and a flexible patterned electrode array layer.In addition,the 3D force detection and slip determination principle of the tactile sensor array are described in detail.In Chapter 3,the micro-manufacturing process of the flexible tactile sensor array was proposed,and the material selection and prototype production are completed.The sensitive material is Inastomer conductive rubber produced by INABA RUBBER Co.,ltd.The hardened PDMS is used as the bump and encapsulation's material,and the patterned gold-plated electrode is processed on the PET substrate as the bottom electrode.The silicone plastic adhesive and the conductive copper adhesive will be used to tightly bond the layers.Then,the signal acquisition system of the tactile sensor array is designed,and the performance test platform of the tactile sensor array is built.Then,we test the repeatability,consistency and stability of the tactile sensor array.The calibration between the three-dimensional force and voltage is also completed.In Chapter 4,an experimental platform for intelligent robot hand's objects grasping is established.Taking two common grasping modes of intelligent robot hand(fingertips pinching and palm grasping)as examples,the three-dimensional force distribution and its causes are studied by means of simulation analysis and experimental test.In Chapter 5,the simulation analysis and experimental test of grasping three objects of different shape are carried out.The three-dimensional force distribution in the process of grasping plane contact objects,cylinder contact objects and spherical contact objects is analyzed.And further realize the slip judgment in the grasping process based on wavelet transform method.In Chapter 6,the main research work of the thesis is summarized,and the future research work is prospected.