Tham khảo tài liệu 'mobile robots perception & navigation part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 6 Optical Three-axis Tactile Sensor Ohka M. Graduate School of Information Science Nagoya University Japan 1. Introduction The three-axis tactile sensor has attracted the greatest anticipation for improving manipulation because a robot must detect the distribution not only of normal force but also of tangential force applied to its finger surfaces Ohka M. et al. 1994 . Material and stability recognition capabilities are advantages of a robotic hand equipped with the three-axis tactile sensor Takeuchi S. et al. 1994 . In peg-in-hole a robot can compensate for its lack of degrees of freedom by optimum grasping force allowing an object to move between two fingers using measured shearing force occurring on the finger surfaces Brovac B. at al. 1996 . Also a micro-robot would be required to remove any object attached to the inside a blood-vessel or pipe wall Guo S. et al. 1996 Mineta T. et al. 2001 Yoshida K. et al. 2002 . It therefore becomes necessary to measure not only the normal force but also the shearing force. Principle of the three-axis tactile sensor is described in this chapter. The authors have produced three kinds of three-axis tactile sensor one columnar and four conical feelers type none columnar feeler type for micro robots and a hemispherical type for humanoid robotic hands. Finally a tactile information processing is presented to apply it to robotic objectrecognition. The information processing method is based on a mathematical model formulated according to human tactile sensation. 2. Principle of Three-axis Tactile Sensor Optical tactile sensor Tactile sensors have been developed using measurements of strain produced in sensing materials that are detected using physical quantities such as electric resistance and capacity magnetic intensity voltage and light intensity Nicholls H. R. 1992 . The optical tactile sensor shown in Fig. 1 which is one of these sensors comprises an optical waveguide plate which is made of transparent acrylic and is .