3。 Research on support controller

The controller is the core of electro-hydraulic control system support。 The design level of controller determines the entire level of the system。 The foreign controller is achieved by using processors in not only the Germany companies, such as MARCO, EEP and TIEFENBACH and so on, but also the American companies。 Domestic inpidual owners or scientific researchers try to use the programmable logic controller (PLC) to achieve the core processing。 Practice shows that it has relatively high anti-interference performance, but is not suitable for special underground applications because of the factors such as large, bulky, designed inflexible, in application program (IAP) not achieved, self-address not automatic identification。 Development in foreign countries is earlier, so the vast majority uses the ordinary MCU as the core processor。 Currently with the development and progress of technology, there are many high-performance processors such as ARM, DSP etc。 However, in consideration of the factors of design features, the power consumption and overall cost etc, the enhanced processor compatible with MCS-51 has been chosen。 The block diagram of the controller using the processor as the core is shown in Fig。 2。

Peripheral configuration in the controller is considered to meet not only the current needs but also the expansibility。 The number of the drive outputs for electromagnetic pilot valves is 20。 The number of the analog input is usually 3 used for sampling signals of displacement, pressure and infrared。 And the designed is 6 for the measurement of the angle and multi-pressure in the future。 In addition, there are two switching output interfaces for the sound and light alarm and two switching input interfaces for the emergency shutdown switch and the lock switch。

In addition to conventional design for reliability in hardware and software, there are three special treatments used, namely, the closed-loop feedback mechanism, the drive output of multiple control mechanism and the drive stop linkage mechanism。 Firstly, the closed-loop feedback mechanism ensures the drive control accurate and  reliable。 The closed-loop feedback mechanism means comparing the drive actual output state sampled by the processor with the expected output state calculating on the basis of the command。 And if the compared result is the same, the processor keeps running。 Otherwise, it takes measures to stop the drive output immediately avoiding losing of life and property。 Secondly, the drive output of multiple control mechanism indicates that the implementation of the drive command needs multiple-control through hardware。 For example, before the main switch is off, the sub-switch turned on can not implement the action。 Therefore, when the sub-switch turning off cannot take effect in  hardware, it is possible to turn off the main switch to stop the unexpected drive output action。 The last is the drive stop linkage mechanism。 The multiple-site survey has found that mine workers are used to use emergency shutdown switch to stop action in the event of failure。 In order to avoid failure of the emergency switch concerning the safety, it is linked with the lock switch in the hardware circuit。 In this case, when the incident occurred, pressing the emergency switch, means pressing the lock switch simultaneously。 So if the failure of the emergency switch occurs, the lock switch still works to ensure the safety of workers。

The modular design is adopted in software design。 Different hydraulic shields are collocated at different mines。 And this brings the differences in software for high performance of control unit。

4。 Research on host computer

Host computer is mainly composed of software and hardware, and it forms communications network through

field bus and all controllers, which is real-time monitoring the work states of every hydraulic support。