Research On Virtual Reality Based Teleoperation Engineering Robot System

Teleoperation robot technology is a branch of robot technology like the industrial robot technology. In a teleoperation robot system, the operator and the perform part are separated and placed to different positions. In the meantime, the operator is included into the control loop and performs the control and decision-making task. By such a structure, the teleoperation system can implement complicated tasks in a extreme environment. Since the 90's in the last century, along with the development of the virtual reality and the network technology, the Teleoperation technique develops continuously combine with other technical realms such as the medical treatment, disaster spots, space and the ocean explore etc. Remarkable achievements have been made.Now, Virtual Reality in teleoperation technology are warmly focused on. In the teleoperation system, human is a part of the control loop, so the system must be fit for human. The Virtual Reality technology is a valid means that provides the operator a immersed world, in which the operator can contact with the work spot freely. The achievements of Virtual Reality on improving vision and force telepresence and solving problems like time-delay have already been generally accepted.This Ph.D. dissertation developed under the project named"Force bilateral servo control of the teleoperation six-degrees-of-freedom (6 DOF) hydraulic parallel manipulator (No.50475011)"supported by National Natural Science Foundation of China and"Study on new type force sense bilateral servo control of teleoperation construction robotic"supported by Excellence Youth Teacher State Program of Ministry of Education (2003). This dissertation aims at the virtual reality system and the control theory as well as the control strategies of master-slave teleoperation system. The following titles are researched:1.A Virtual Reality system suitable for teleoperation system is built up, which has a great assistance function to the teleoperation system. To get the information from the work spot, 3D object reconstruction is adopted based on image processing with a Digiclops device first interiorly. In such a way, a substitute of the work object is reconstructed in the Virtual Reality environment, which can be used to provide the operator the vision information from the work spot. With such a method, the work object at the work spot can be created in the master part with simple information so that the operator can get vision information with less time delay.2.A new teleoperation system communicating by LANs is built consists of force feedback manipulator as master part and electron-hydraulic servo system as slave part. The operator in the system can be feedback by various information including video camera, virtual environment and the force feedback etc. Aiming at the control of the Teleoperation system has high real time request and the communication between the master part and slave part has the characteristics of various datasets, each kind of the data is divided into different types according to the accuracy, data size and mission etc. The types of data includes the space information, the time information, the teleprogramming orders, the system order and the text information etc. A communication system receive data by asynchronism series is set up. To keep the synchronization of master and slave parts, the time adjustment function is added in the system.3. The gravity compensation method by system identification is discussed for the first time interiorly. Based on the mathematical model of electron-hydraulic servo system and dynamic model of the engineering robot, the gravity parameters are abtained by least squares. The algorithm is proved to be available by experiment in the teleoperation system.4. A gain-switching force feedback algorithm is built up for the folkglove of the robot. The algorithm decreases the force arosed by inertia and damp force by dynamical parse, and it is proved to be available in the teleoperation system.The dissertation also includes the following parts:1.The following contents are in the first part: the application of the normal hydraulic teleoperation system, the latest achievement of virtual reality and how to use virtual reality to improve the performance of the teleoperation system.2. The overall of the system are expatiated, including the following parts: the master-slave system, the video system, the object reconstruction system and the timer. Each part is introduces as the constitutes and it's function in the teleoperation system.3. To the time delay and increase the visual field of the video system. A virtual enviorment is built for vision feedback. According to hydraulic cylinder length and the kinematics model of the slave robot, the pose of the robot is simulated on-line. Such a system increases the vision feedback capiblity of the teleoperation system.4.An overall analysis was carried on toward the mathematical model of the the Master-slave system: the kinematics model, dynamical model and electron-hydraulic servo system mathematical model of the 2-DOF hydraulic force feedback manipulator are built up. Also the simplified dynamics model and electron-hydraulic servo system linearized mathematical model servo model of the 4-DOF robot in the slave part are built up.It is proved by experiments that the teleoperation system performs well on real-time operation and provides the operator good vision and force feedback. So that it can be used to implement an engineering teleoperation task.