Research On Multi-dimensional F/T Sensor For Specific Applications

Intelligentization is one of the main trends of research and development of the robot technology, and the sensing and feedback system is very important to the intelligent behaviors. Multi-dimensional Force/Torque sensors are capable of detecting force and torque information while the robot operates with environment, which can be used for achieving haptic, tactile and slip sensations and have gotten wide attentions of the experts. With the development of modern robotics, from underwater robots to space robot, from miniature fingertip to teleoperation system, from micro-manipulation such as cell operation to heavy load cell, multi-dimensional F/T sensors pay an important role in development and application of industrial technology, and more and more specific applications of the multi-dimensional F/T sensors with high performance are required.This thesis discusses the status and development trends of multi-dimensional F/T sensor applications for specific applications. Based on the relevant projects of the Robot Sensor and Human-Machine Interaction Laboratory, we try to further understand how F/T sensors work and perform job better and design and fabricate novel F/T sensors to fit more and more specific applications. Main works we do in this thesis may be summarized as follows:1. Due to the requirements such as miniaturization, anthropomorphism, and high sensitivity about fingertip F/T sensor for robot grippers, we design and fabricate novel four-dimensional and five-dimensional fingertip F/T sensors for different projects. By the deficient-dimensional F/T sensors, coupling between the components can be reduced so that the performances of the sensors can be improved, and the complexity and cost of the system can also be reduced. With novel structures of the elastic bodies, reasonable arrangement and electrical bridges of the strain gauges, and effective decoupling method, high sensitivity, high reliability and high accuracy of the developed F/T sensors are realized.2. As the harsh underwater environment featured by high water pressure that changes with increasing water depth, non-linear variation of temperature, corrosion, etc., general F/T sensor cannot be applied to the underwater environment. With novel elastic body, pressure and temperature compensation, seal technology, overload protection, a new type of six-dimensional F/T sensor for underwater robot. The novel structure of the elastic body has been also used as a ultra-thin six-dimensional F/T sensor for general purpose with its lowest size in height.3. Because of the advantages of the parallel mechanisms such as high stiffness, high load capacity and high precision, we focus on developing a new humanoid robot foot based on a novel parallel mechanism with integrated six-dimensional F/T sensor. The method and principle of measuring force and torque with parallel mechanism-based F/T sensor have been introduced. The mechanism is comprised of three actuated limbs and one passive limb, which possesses three rotational degrees of freedom and is used to realize human foot/ankle function. With the force and torque information provided by the integrated F/T sensor, the humanoid robot could stand and walk in unknown environment.4. Based on parallel mechanism and compliant joints, a micro-manipulator based on a novel compliant parallel mechanism has been introduced. The micro-manipulator are featured by integrated F/T sensor, which provides real-time force and toque information to the closed-loop control so that the performance and accuracy of the system can be improved. The system realizes integration of structure, driver and sensor, and could achieve micro-level precision.