Biography
Enrollment Date: 2012
Graduation Date：2015
Degree：M.S.
Defense Date：2015.06.03
Advisors：Chun Zhang
Department：Institute of Microelectronics，Tsinghua University
Title of Dissertation/Thesis：The design of optics-based haptic sensor
Abstract:
With the development of robotic science, the precise robot manipulation is an urgent need for the important parts of national economy such as precision instruments manufacturing, science experiment, helping the olds and disables and healthcare. To achieve precise robot manipulation, we must solve the problem of dual information measuring such as force, touch and slip in complex environments and the problem of manipulated object characteristic measuring. So the need of precise tactile sensor of human-like hands is growing more and more.
Compared with the traditional tactile sensor, optics-based tactile sensor has a better property, less influence of environment and higher interference resistance. This thesis makes a research of the design of optics-based tactile sensor and designs an optics-based tactile sensor with the consideration of signal processing hardware complexity, the feasibility of tactile sensor small sized and the difficulty of tactile sensor manufacturing.
The tactile sensor is made of human-skin-like elastic material with markers on its surface. The camera catches the image of markers and the force distribution is calculated by measuring the movements of markers when a force is applied on the elastic material. The tactile information calculation by the movement of markers is based on the elastic theory.
The signal processing circuit for the related algorithm is based on hardware and Nios-II core software. The thesis designs a special accelerated circuit for the image scanning and marker identifying and calculates the movement of markers by centroid method. The calculation of applied force is complex comparatively, but its amount is small, so it is achieved by Nios II.
The thesis makes a research on configuration of robotic hands and tactile sensor, the choice of elastic material and the design of signal processing circuit. The micro-size signal processing circuit is made so that the whole tactile sensor system can be put into the first and second knuckle of the robotic hands and the tactile information can be output directly. The signal processing circuit is made of camera, signal processing PCB and configuration PCB. A FPGA chip and an SRAM chip are put on the signal processing PCB and a configuration chip and power supply chips are put on the configuration PCB. The two PCBs are piled together by the contact pin to satisfy the space size requirement of the robotic hands.