Research On Flexible Multi-dimensional Array Tactile Sensor Based On Pressure Sensitive Conductive Rubber

With the development of robot technology, the research of flexible multi-dimensional tactile sensor used in intelligent robot, in particular bio-robot and service robot has more and more important. As the flexible multi-dimensional tactile sensor has a measurement functions for contact pressure distribution of any material and free-form surface, which it have wide application prospect in many fields such as athletic training, medical rehabilitation and sport biomechanics, etc.This dissertation is originated from the National Natural Science Foundation (No. 60672024) and National High Technology Research and Development Program (863 Program No.2007AA04Z220). The paper deals with a comprehensive application of theory and technology based on materials science, nanotechnology, sensor technology and artificial intelligence. In view of the current situation in the research and application of multi-dimensional array tactile sensor can not simultaneously meet the requirement of flexibility and obtaining multi-dimensional force information, the innovative research on sensor materials, preparation, and the structure of sensor is carried out. The major research and innovative results are as follows:1. Based on in depth analysis of the structure, between interactions mechanisms, physical and chemical properties of various materials for pressure sensitive conductive rubber, the new material formula of high flexibility and high conductivity is proposed. The new preparation technical of the economic feasibility for pressure sensitive conductive rubber in Liquid Forming is studied, which makes it possible to prepare the flexible tactile sensor array that can be molded randomly.2. The conduction mechanism of pressure sensitive conductive rubber is discussed by making use of macro conductive path theory and micro tunnel current theory. The non-linear percolation conductivity phenomenon and the main affecting factor of piezoresistive properties for pressure sensitive conductive rubber are comprehensively analyzed. Through theoretical analysis and experimental study, a scientific basis for the suitable ratio of carbon black as conductive filler is provided.3. The microstructure and physical properties of selected Nano-modified material in polymer are theoretical analyzed. The action mechanism of nano-modified materials for the pressure sensitive conductive rubber is studied. Based on the modification of pressure-sensitive conductive rubber made use of nano-materials, the new method to enhance the material properties is proposed for the first time. The performance of piezoresistive / creep / temperature / anti-aging of pressure sensitive conductive rubber filled with nano-SiO₂ and nano-Al₂O₃ are calibrated and compared. The experimental results show that nano materials can remarkably improve a number of characteristics of pressure sensitive conductive rubber.4. The two types of innovative structure of flexible multi-dimensional array tactile sensor are developed, one is overall multi-layer net array structure based on body piezoresistive effect, and the other is single-layer array structure based on interface piezoresistive effect. The sensors based on the above two structures are respectively given force analysis, and the mathematical model to detect three-dimensional force information is established. Through experiments, their own characteristics and main sources of error of the two structures are researched and analyzed. The result shows that the detection of three-dimensional force information can be effectively realized for flexible multi-dimensional array tactile sensor based on the two structures and mathematical model.The new type of pressure sensitive conductive rubber can be molded in liquid of this paper not only has good mechanical and electrical properties, but has the characteristics of production of low cost and simple, easy preparation; The developed flexible multi-dimensional array tactile sensors is similar to human skin which has function to obtain information of three-dimensional force. The work and obtained achievements in the paper will lay a good foundation for further study on popularization and application for robot sensitive skin and flexible tactile sensor application.