TECHNICAL FIELD

The present invention belongs to the field of teaching application, and relates to a teaching system for remote hydraulic experiments based on combination of virtual and real.

BACKGROUND

Experiment teaching is an important teaching link for science and engineering students, and is also an important way to cultivate students' practical ability and innovative thinking. Through the experiment link, a student can better master abstract theories, learn basic knowledge and skills, and develop the ability to analyze and solve problems. At present, the problem in experiment teaching is how to enable a student to remotely control laboratory equipment and complete corresponding experiments without being limited by time and location. Virtual simulation teaching is one of the means to solve the problem. Virtual simulation experiments based on combination of virtual and real not only assist teachers and schools in scientific research, but also have the advantages of high shareability, high security, high economy and friendly human-computer interaction interface in the teaching aspect. Automation Studio software is arranged at the computer terminal of a hydraulic experimental platform, so that the student may use this easy-to-use and powerful professional circuit simulation software in a mode of remote call. In this way, the student may use the software remotely at any time to perform the operations of simulation, practice and re-simulation. By means of such a complete set of processes, not only the remotely called experiment platform is controlled automatically and intelligently, but also the student is made to obtain better experimental experience and more optimized experimental results.

SUMMARY

By combining the construction requirements of a hydraulic virtual simulation laboratory, the present invention designs a virtual simulation teaching system for remote hydraulic experiments based on combination of virtual and real. In the virtual simulation teaching system, the virtual and real combination part involves that a hydraulic circuit is simulated by a student by remotely calling the Automation Studio software on the experimental platform, the hydraulic circuit is modified and optimized according to the idea of the student, and the hydraulic experimental platform is connected finally to perform actual operations. The system is also added with a network HD ball machine, a network video recorder (NVR), a switch, a ball machine bracket, a router and other devices to form a feedback system, so the student can observe the real-time operation of the hydraulic experimental platform through the feedback system.

To achieve the above purpose, the present invention adopts the following technical solution:

A teaching system for remote hydraulic experiments based on combination of virtual and real, comprising the following steps:

Step 1: controlling Teamviewer software to implement remote access, and additionally setting six essential trigger buttons:

the remote access means that a student client can remotely control the desktop of an upper computer of a hydraulic experimental platform. Teamviewer connection is an application that can be used for remote control in the background of any firewall or NAT proxy, enabling the client and the hydraulic experimental platform to implement desktop sharing, file transfer and other functions. The remote access software can acquire access to the upper computer of the hydraulic experimental platform of the laboratory by starting the Teamviewer remote connection.

The additionally set six trigger buttons respectively correspond to Start remote control, Request to open the hydraulic pump, Record video, Complete recording, Request to close the hydraulic pump, and Complete experiment. The Start remote control part means that when the remote access software initially operates, the part continuously updates the remote access software through the network; and when the Start remote control operates, the remote access software acquires information about the project definition of the position control experiment, the design drawing of the hydraulic circuit, the type and number of used hydraulic components, and the purpose and requirements from the experiment project library. The Request to open the hydraulic pump means that as a first exchange button of the remote access software, the part issues a start command to the laboratory experimenter through the sound equipment of the hydraulic experimental platform. The Record video means that as a supervision part established by the remote access software, the supervision part acquires compressed video by performing frame fetching on the screen of the client computer at regular time. The Complete recording means that as a termination control part of the record video button of the remote access software, the Complete recording stops the frame processing of the record video supervision part and terminates the operation of the Record video. The Request to close the hydraulic pump means that as a second exchange button of the remote access software, the part issues a termination command to the laboratory experimenter through the sound equipment of the hydraulic experimental platform. The Complete experiment means that as operation termination button of the remote access software, the part performs protocol termination on the Teamviewer remote connection.

Step 2: To achieve combination of virtual and real, building an electrical circuit to control the hydraulic experimental platform through Automation Studio software:

the built electrical circuit comprises a 24V power supply, a command value module, a controller module, a command value specification module, a command value/actual value display, a position sensor and a wiring board, wherein the command value module, the controller module, the command value specification module, the command value/actual value display and the wiring board are connected with the 24V power supply respectively; the command value module is connected with the controller module; the signal sending end of the position sensor is connected with the controller module, and a receiving device of the position sensor is installed on an operating platform of the hydraulic experimental platform; the command value/actual value display is connected with the controller module, and is mainly responsible for receiving the data of the controller module and displaying same graphically and digitally; the input end of the wiring board is connected with the command value specification module and the controller module respectively by contact switches, and the output end thereof is connected with hydraulic components on the hydraulic experimental platform, playing a role of transferring signals;

the Automation Studio is installed at the upper computer terminal of the hydraulic experimental platform to transfer commands, and is capable of achieving dynamic simulation of electro-hydraulic control and co-simulation of other software; the student may perform virtually simulated hydraulic circuit connection and electrical circuit connection according to the hydraulic circuit diagram and electrical circuit diagram of this project. On the premise of not modifying the functions of various hydraulic circuits in the experiment, the student may use the Automation Studio to modify the position of each hydraulic circuit component and the layout of the tubing connections according to his/her idea. In a similar way, when building the virtual electrical circuit, the student may use the Automation Studio to modify electrical parameters such as amplification coefficient and the like according to his/her idea.

For the virtual and real combination part, the experimenter fixes the position of each hydraulic component on the hydraulic experimental platform according to the hydraulic circuit diagram of the experiment project, and connects various hydraulic components using tubing to form an actual hydraulic circuit; and in a similar way, for the electrical circuit, the experimenter needs to build an actual electrical circuit on the hydraulic experimental platform according to the electrical circuit diagram of the experiment project; by remotely accessing the Automation Studio software at the upper computer terminal of the hydraulic experimental platform, the student performs virtually simulated hydraulic circuit connection and electrical circuit connection according to the hydraulic circuit diagram and electrical circuit diagram of the specific project; in the process of operating the Automation Studio software, on the premise of not modifying the functions of various hydraulic circuits in the experiment, the student may modify the position of each hydraulic circuit component and the layout of the tubing connections according to his/her idea, and in a similar way, the student can modify electrical parameters such as amplification coefficient and the like according to his/her idea; and finally, the virtual simulation circuit is connected with the actual circuit to verify whether the virtually simulated hydraulic circuit of the student is correct.

The actual hydraulic circuit and the actual electrical circuit are circuits formed for different hydraulic experiment items. Hydraulic experiment items correspond to two circuits of hydraulic circuit and electrical circuit.

Step 3: Establishing a closed-loop feedback system, and establishing contact between the student and the hydraulic experimental platform:

the hardware part of the feedback system comprises a hydraulic experimental platform, a network HD ball machine, a network video recorder, a switch, a router and a client computer.

3.1) Installing the network HD ball machine, and setting preset points for the network HD ball machine:

the network HD ball machine is connected with a camera and is installed on the ball machine bracket, and is oriented to the upper half of the hydraulic experimental platform to acquire the layout and operation information about the hydraulic experimental platform; the network video recorder is interconnected with the network HD ball machine and the switch respectively by interfaces, and the acquired information about the hydraulic experimental platform is uploaded to the upper computer of the hydraulic experimental platform by the system through the switch.

The configuration platform controlling the network HD ball machine is installed at the upper computer terminal of the hydraulic experimental platform after hardware is installed, and preset points of experiment components are set in the channel management of the main menu of the configuration platform.

3.2) Configuring a network for equipment at the laboratory terminal:

the router is installed near the wired network interface of the laboratory. The hydraulic experimental platform is mainly used for teaching training of hydraulic technology, is capable of performing modular structural design and quick disassembly and connection of components, and is connected with the upper computer to receive the network and install Automation Studio software for controlling hardware equipment. The upper computer terminal can obtain a wireless network; the client computer is connected with the network video recorder of the hydraulic laboratory by the network; the network video recorder is connected with the preset points set by the computer to control the network HD ball machine, so as to establish a closed-loop feedback system to feedback adjustment functions.

3.3) Mobilizing hardware of the feedback system using the Teamviewer software and the configuration platform of the network HD ball machine:

the client accesses the upper computer of the hydraulic experimental platform connected to the router through the Teamviewer software, and the configuration platform of the network HD ball machine at the upper compute terminal is started. According to the connection modes in steps 3.1 and 3.2, after the configuration platform is started, the network HD ball machine starts to acquire real-time data of the hydraulic experimental platform, and the network video recorder collects data through the network HD ball machine and then encodes same to generate images. The switch uploads the images generated by the network video recorder to the upper computer of the hydraulic experimental platform. The client views real-time images on the configuration platform of the network HD ball machine through the Teamviewer software.

After the feedback system is established, the student can acquire the image of the hydraulic experimental platform of the laboratory through the system and control the network HD ball machine through the preset points.

The present invention has the advantageous effects that: the virtual simulation teaching system for remote hydraulic experiments based on combination of virtual and real adds opportunities for the student to come into visually close contact with the experimental platform while breaking through time and location limitation; since the .NET-based remote access software uses the mode of encapsulating Teamviewer remote software, reduces the time delay of client video and real-time operation of the hydraulic experimental platform of the laboratory in the case of guaranteeing the fluency of control effects; and implements the control connection between the Automation Studio software and the engineering-level hydraulic experimental platform using the electrical circuit design, and acquires real experimental representation and experimental data. This method allows the student to easily implement the core components of task configuration and programming through the Automation Studio software. The graphical hardware and software configuration can clearly outline the whole project, process variables and data are symbolically addressed here, and the system may automatically identify and support target hardware.

