The rapid development of microprocessor technics and telecommunication technologies highlights the "cloud" services that allow users to have universal access to various computing resources (servers, applications, services).Remote control of technical objects via the Internet is one of the main technology sectors, which recently gaining more and more popularity. Nowadays, technological progress enables to realize real-time control of various technical objects physically removed at a sufficient distance from the user or the master device. Such control technology is actual in many fields of science (e.g., synthesis and testing of control algorithms in conditions of time delay or other channel restrictions) and industry automation (hazardous manufactures), robotics (for search and rescue operations in remote locations, etc_.
One of the problems on which the activity of“Laboratory of nonlinear and adaptive control systems” is aimed is development of a universal architecture of the different robotic objects remote control via the Internet. There are three main objectives: the design of hardware-software complex, which will have universal remote control architecture; development of a vision system to control the position of the control object in workspace; synthesis of mobile robot prototype which operates in terms of time delay.
The first task is to design universal system architecture for control of robotic objects via the Internet regardless of the object location and its master device or the end user location. Availability and the ability to connect to the Internet, as a remote control channel, object and its master device or computer end user is a necessary condition.
Solution of the task was accomplished in two stages. At the first stage transfer of telemetric information between the object and the end user or master control unit was organized. Control object and end user may be located at a far distance from each other. To provide transfer of information, software allowing to establish a permanent connection between them has been developed and requirements for the system hardware allowing the implementation of the proposed architecture in existing robotic objects were developed.
At the second stage visual control of remote technical object position for the end user was organized. For the implementation of visual monitoring the broadcasting of live video from the object (for example, in the case of search and rescue), or from outside (for example, in the case of using the system in production) was provided. The manner of broadcasting is determined by the specifications of the task.
Development of the vision system for the control of the robotic object position in workspace was divided into three stages. The first stage was the selection of the camera type. Then the optimal broadcast available for most of users was determined. The organization of video translation to the Internet with the purpose of unloading the local network to which the system is implemented was the final step.
Further, mobile robot motion control system of mobile robot motion in the architecture of the remote control was developed. Control system is able to function in conditions of the time delay, as well as the inherent structural and parametric uncertainties. For this purpose the control algorithm based on the method of consecutive compensator was used.
Experimental data show that the delay of the video images of the developed system is about 500 ms for control via the Internet. The reaction time of adult humanis about 200ms. Delay in the control channel varies depending on the server response time. In this experiment server response time was 3-10 ms. For more complex conditions we use the higher level of delay and define it as 100 ms. Thus, the delay in the feedback loop is 700 ms and in the control circuit is 100 ms.
For testing of the developed control algorithm a numerical simulation of the application package in MATLAB Simulink and a series of experiments were conducted. The simulation results and practical applications confirm the operability and effectiveness of the proposed methods and approaches.