Research On Video Transmission And Remote Control Of Mobile Robot

With the rapid development of wireless network technology in the world, and the efforts of countries to improve the coverage of wireless network, the scenarios and application mode of wireless network technology have changed a lot. These changes make visualization remote control of mobile robot with wireless network technology become possible gradually. It has great value in research and usage in many fields. In practical application, however, it is difficult to guarantee the real-time video transmission and the reliability of the control instruction transmission, because of the flaw of network transmission rate, coverage scale and stability of wireless network. It hinders the development of video transmission and remote control technology of the mobile robot to a large extent. This paper analyses the demand of AS-RF mobile robot platform, and the research focuses on the following two aspects: wireless video transmission and control commands transmission.In wireless video transmission of mobile robot, the traditional wireless video transmission facing two big difficult problems: the video codec and the streaming media transmission control. This paper focuses on the analysis and improvement of the streaming media traversal technology which based on ICE protocol. Traditional real-time video transmission method based on C/S architecture needs remote server to transfer real-time video streaming, and the streaming media traversal method based on ICE protocol provides end-to-end real-time video transmission first. If the end-to-end connectivity is not reachable,the video streaming will be transferred via TURN servers. ICE protocol can greatly improve the efficiency of video transmission. Traditional ICE protocol can't traversal symmetric NAT effectively, this paper applying a connection-oriented traversal method for improvement. The traditional ICE protocol streaming media traversal method doesn't do well on the performance and deployment, referring to the solution of Skype, this paper introduces an idea of P2P for load balancing, in order to solve the system load problem brought by the quantity increasement of robot end and control end.In control commands transmission of mobile robot, this paper uses a transmission method based on XMPP protocol. Because the XMPP is a real time communication protocol based on TCP, to some extent, it not only improves the real-time ability of control commands transmission, but also enhances the reliability, expansibility and security of control commands transmission.The system is tested from two aspects: the performance tests of streaming media traversal and the performance tests of control commands transmission. In the performance tests of streaming media traversal,we collect data of call setup time,end-to-end delay and packet loss rate. By comparing the data before and after the improvement of streaming media traversal method in three different kinds of network topology, results show that the improved method achieve a 17% enhancement in real-time ability. In performance tests of control commands transmission, we collect data of action response time of control commands transmission under different network conditions, and the results show that the action response time can be controlled within 100ms under good network condition, which achieve the desired effect of the experiment. In general, this paper can meet the system's requirement analysis in real-time ability, stability and expansibility, achieves the expected goals, and has great value in research and usage.