In order to ensure the safety and smooth driving environment of highway, reduce or prevent the impact and harm caused by snow on road surface, snow removal and skid prevention in winter has become an important work of highway maintenance. Therefore, people pay more and more attention to the development of a multi-functional snow removal vehicle with high snow removal efficiency, low cost and low pollution. The controller of the pre-wetting spraying system is installed on the multi-function snow removal vehicle.
It can realize intelligent, accurate and efficient spraying operation by electro-hydraulic control of the hydraulic mechanism. This paper first gives a brief introduction to the pre-wetting spraying system, and then designs the controller of the pre-wetting spraying system of snow removal vehicle from the aspects of controller, signal processor and central processor. The pre-wetting spraying system is based on the digital control chip, and the spraying mechanism is controlled by electro-hydraulic, so that the snow removal vehicle can distribute the mixture evenly on the road according to the set spraying amount and pre-wetting ratio. The whole system consists of a controller and a hydraulic mechanism. The controller is responsible for the operation of the system. The hydraulic mechanism is the executive mechanism of the system and is responsible for the material throwing.
The system has five operation modes: pre-wet spraying mode, salt spraying mode, sand spraying mode, unloading mode and programming setting mode, which can be switched by selecting switches. There are two working modes, automatic mode and manual mode, which are used in different working occasions. Under the automatic mode, the control system can automatically update the parameters of the driving hydraulic motor to meet the requirement of setting the spreading quantity according to the change of vehicle speed and spreading width. This mode is applied to the normal spreading situation. Manual mode, the control system is operated according to the constant speed set by the operator, which is used for test calibration and low-speed special operating conditions. The two working modes can be switched through specific keys. When the spraying operation is normally executed, press the full speed execution key or set the speed execution key, the system will drive the hydraulic motor with full parameters or set parameters to meet the spraying requirements of maximum and set spraying quantity, which is very useful in special and dangerous areas.
In addition, when the spraying operation is carried out, the operator can change the required spraying amount and width at any time according to the specific conditions. Whenever the new data is set, the system will update the parameters of the driving hydraulic motor to meet the new setting requirements. The schematic diagram of the overall scheme is shown in Figure 2.
1. The control structure of the controller is divided into two parts: the central processor and the signal processor. Sensors transmit external signals to signal processors through connecting channels. Signal processors are responsible for detecting, collecting and processing sensor signals. Control signals from central processors are analyzed and processed, and then three analog signals are output to drive the hydraulic mechanism. At the same time, the data to be displayed is transmitted to central processors. The central processor is mainly responsible for generating control information and transmitting control commands to the signal processor. At the same time, it realizes the functions of data display, acousto-optic alarm and so on. The signal processor uses the single chip as the core processor, and chooses the chip and other chips to form the hardware system of the controller. It mainly realizes the functions of acquisition, analysis and processing of each sensor signal, output of analog signal and communication with central processor.
The hardware composition of signal processor should include the conditioning circuit of sensor input signal, power supply system, isolation and amplification circuit of output signal and communication system circuit. It receives the pulse signal of the speed sensor, shapes the pulse signal through the light accident, and then converts it into the level signal that can be received by the single chip computer.
The power supply is provided to the belt pulse encoder, and the pulse signal of the encoder is received. The pulse signal is shaped by the optical coupler, and then converted into the level signal that can be received by the single chip computer. It supplies power to the acoustic sensor, receives the acoustic switch signal, isolates the signal through the optical coupler, and then converts it into the level signal that can be received by the single chip computer. According to the control command and sensor signal, the state of the system is judged, and the corresponding analog voltage signal is output to drive the hydraulic mechanism. By communicating with the central processor through a serial port, control commands and data are received and transmitted in real time. The central processor also uses MCU as the core processor, and the hardware system is composed of real-time clock chip, data storage chip and other functional chips. It mainly realizes the functions of analysis and processing of key and switch control information, data storage, display of operation status, fault alarm and communication with signal processor. The hardware composition of CPU should include keyboard interface circuit, alarm indication circuit, display interface circuit, functional module circuit, power supply system and communication system circuit. Man-machine channel sends control commands to signal processors and receives real-time data from signal processors, thermostatic element which is processed and displayed at last. Fault alarm indication, with sound and light alarm function.
Job data and operation parameter storage function.
Date and time display function. By communicating with signal processor through a serial port, control commands and data are sent and received in real time.
With the development of society and the improvement of mechanization technology, people urgently need a kind of machine with good performance and high automation to replace the traditional snow-clearing method. The development of multi-function snow-removal vehicle is proposed under this background.
It adopts speed navigation automatic distribution control system, which overcomes the inaccuracy and inefficiency of single-stage or multi-stage speed regulation in traditional snow-melting spreader. The controller of the pre-wetting spraying system proposed in this paper can be said to be the “brain” of the multi-functional snow removal vehicle. It is under the control of this controller that the snow removal vehicle can automatically complete the spraying operation according to the regulations. Therefore, the development of this controller plays an important role in promoting the development of a new type of multi-functional snow removal vehicle.