Low-cost hydraulic execution part control system and methodTechnical Field
The invention relates to a low-cost hydraulic execution part control system and a low-cost hydraulic execution part control method, which are applicable to the field of machinery.
Background
With the continuous development of industrial automation, hydraulic control technology has become an indispensable key technology in industrial equipment. In recent years, sensor signals in the hydraulic industry are more and more diversified, and meanwhile, the conditions of improper sensor signal range selection and poor sensor and controller matching occur sometimes, which brings great challenges to the compatibility of an input circuit. Along with the development trend of liquid drive electric control in the hydraulic industry, the pilot control unit of the electromagnetic switch cartridge valve on the market has the problems of impact, noise and the like during action switching, and the control system of the proportional valve enables hydraulic action to be smoother, has operability and simultaneously needs energy saving and noise reduction effects. The electrohydraulic switch control meets the requirements of discontinuous control and control precision, and the electrohydraulic servo control technology with high precision and quick response is complex and has higher cost.
Disclosure of Invention
The invention aims to provide a low-cost hydraulic execution part control system and method, wherein the control system comprises a multiplexing input circuit which meets the diversification of the current sensing signals, can realize open-loop control to meet the requirements of stable output and lower cost, and can realize closed-loop control by feeding back the acquisition of output current to an MCU through hardware, thereby greatly improving the control precision, ensuring that the output does not change along with the change of a load valve block, and has reliable work and strong anti-interference capability and also meeting the requirements of continuous control and control precision.
The hydraulic execution part control system comprises a power supply module, an input acquisition module, an MCU, a driving module, a communication module and a display module, wherein the power supply module is used for decoupling and filtering an input power supply and converting the input power supply into voltages required by normal operation of the MCU and an external sensor, the input acquisition module is used for receiving input signals from different types of sensors and converting the input signals into input levels recognizable by the MCU under the control of the MCU and then transmitting the input levels to the MCU, the MCU is used for acquiring the input levels, converting the input levels into control signals of the hydraulic execution part according to a preset conversion mode and then transmitting the control signals of the hydraulic execution part to the driving module, the driving module is used for responding to the control signals output by the MCU and selecting an open loop or closed loop circuit to drive the hydraulic execution part to act, the communication module is used for ensuring that the hydraulic execution part control system is correctly communicated with an upper computer, and the display module is connected with the MCU and used for displaying state information of the hydraulic execution part control system.
The method comprises the following steps:
S1, an input acquisition module transmits an input signal from a sensor to an MCU, the MCU firstly controls the input acquisition module to select the input configuration of the input sensor according to the type of the input signal, and then the input acquisition module converts the input signal into an input level and transmits the input level to the MCU;
S2, continuously acquiring input levels for preset times by the MCU, performing pre-filtering calculation, and entering a step S3 if the continuously acquired input levels exceed a preset error range, and entering a step S4 if the continuously acquired input levels are within the preset error value range;
s3, marking the input level as failure voltage by the MCU, marking the output state as 0 by the MCU, and returning to the step S1;
S4, the MCU marks the input level as effective voltage, the MCU collects preset external factors and the working state of the executive component, if the external factors do not meet the preset conditions or the working state of the executive component is abnormal, the MCU marks the output state as 0, and meanwhile, the MCU displays the external factors which do not meet the preset conditions or the executive component with the abnormal working state through a display module to prompt a fault phenomenon;
S5, detecting an output state by the MCU, if the output state is 0, closing the driving module, and enabling the hydraulic execution part to be not operated, if the output state is 1, opening the driving module, and then entering a step S6;
s6, the MCU acquires the preset driving circuit information in the driving module, if the driving module is driven by an open-loop circuit, the step S7 is carried out, and if the driving module is driven by a closed-loop circuit, the step S8 is carried out;
S7, the MCU adopts an open loop control method to control the driving module to drive the hydraulic execution part to act, and then the step S1 is returned;
And S8, the MCU controls the driving module to drive the hydraulic execution component to act by adopting a closed-loop control method, and then the step S1 is returned.
Further, the input acquisition module can provide input configurations for the input sensor, wherein the input configurations comprise 0-5V analog input, 0-36V analog input, pull-up input, pull-down input, suspension input, GPIO input and PWM input.
Further, the output current response MAP refers to a functional relationship between the effective level and the output current, and the abscissa of the output current response MAP is the effective voltage and the ordinate is the control current.
The open loop control method is characterized in that when an input signal is of an effective level, the MCU transmits corresponding control current to the driving module according to an output current response MAP, the MCU outputs a PWM wave signal to the driving module, the MCU calculates a corresponding duty ratio of PWM wave output according to the magnitude of the control current, the driving module amplifies the waveform of the corresponding duty ratio output by the MCU into a required voltage of the hydraulic executing component, when the impedance of the hydraulic executing component is unchanged, the driving module can output stable driving current to drive the hydraulic executing component to act, but when the impedance of the hydraulic executing component is changed due to external factors, the driving current is changed along with the change of the impedance of the hydraulic executing component, if the impedance of the hydraulic executing component is increased, the driving current is decreased, otherwise, the impedance of the hydraulic executing component is decreased, and the driving current is increased.
The closed-loop control method comprises the steps that when an input signal is effective voltage, an MCU (micro control Unit) transmits corresponding control current to a driving module according to an output current response MAP, the MCU outputs a PWM wave signal to the driving module, the MCU calculates a corresponding duty ratio of PWM wave output according to the magnitude of the control current, the driving module amplifies the waveform of the corresponding duty ratio output by the MCU into required voltage of a hydraulic execution component, in the control process, the current driving current is acquired in real time by the closed-loop circuit and converted into voltage to be fed back to the MCU, the MCU adjusts the duty ratio of PWM wave output according to the feedback voltage, the voltage of the hydraulic execution component is changed, finally, the driving current output by the driving module is kept the same as the control current, based on the closed-loop control method, the driving current output by the driving module does not change along with the change of a load, and the hydraulic execution component control system can continuously and stably control the action of the hydraulic execution component.
Compared with the prior art, the control system and method for the low-cost hydraulic execution component have the following technical effects:
1. the multifunctional input module is designed, can be configured with different ranges and meets the output requirements of different sensors;
2. The open loop and closed loop control modes can be realized according to different connection methods of the load, so that the load is suitable for a plurality of occasions and has strong driving capability;
3. The hydraulic execution component control system has the advantages of quick response, high control precision and strong anti-interference capability, and not only meets the requirements of continuous control and control precision, but also meets the requirements of control cost;
4. The input and output are provided with a protection function, so that the output execution component and the controller can be protected;
5. Can be matched with an upper computer for real-time calibration and monitoring.
Drawings
FIG. 1 is a diagram of a hydraulic implement control system;
fig. 2 is a schematic diagram of an input acquisition module configuration.
Detailed Description
For a better understanding of the technical content of the present invention, specific examples are set forth below, along with the accompanying drawings.
Aspects of the invention are described herein with reference to the drawings, in which there are shown many illustrative embodiments. The embodiments of the present invention are not limited to the embodiments described in the drawings. It is to be understood that this invention is capable of being carried out by any of the various concepts and embodiments described above and as such described in detail below, since the disclosed concepts and embodiments are not limited to any implementation. Additionally, some aspects of the disclosure may be used alone or in any suitable combination with other aspects of the disclosure.
Referring to fig. 1, the hydraulic execution part control system comprises a power supply module, an input acquisition module, an MCU, a driving module, a communication module and a display module, wherein the power supply module is used for decoupling and filtering an input power supply and converting the input power supply into voltages required by normal operation of the MCU and an external sensor, the input acquisition module is used for receiving input signals from different types of sensors and converting the input signals into input levels recognizable by the MCU under the control of the MCU and then transmitting the input levels to the MCU, the MCU is used for acquiring the input levels, converting the input levels into control signals of the hydraulic execution part according to a preset conversion mode and then transmitting the control signals of the hydraulic execution part to the driving module, the driving module is used for responding to the control signals output by the MCU and selecting an open loop or closed loop circuit to drive the hydraulic execution part to act, the communication module is used for ensuring that the hydraulic execution part control system is correctly communicated with an upper computer, and the display module is connected with the MCU and used for displaying state information of the hydraulic execution part control system.
In the embodiment, the control method of the hydraulic execution component comprises the following steps that an input acquisition module transmits an input signal from a sensor to an MCU, the MCU firstly controls the input acquisition module to select the input configuration of the input sensor according to the type of the input signal, and the input configuration provided by the input acquisition module for the input sensor comprises 0-5V analog input, 0-36V analog input, pull-up input, pull-down input, suspension input, GPIO input and PWM input.
Referring to fig. 2, in this embodiment, an input acquisition module acquires an input signal by dividing the voltage, a selector is used for the 0-5V range and the 0-36V range, the range is selected by controlling a distribution pin through the MCU, and a pull-up configuration required by an input sensor is selected by controlling the MCU, and then the input acquisition module converts the input signal into an input level and transmits the input level to the MCU.
The MCU continuously collects the input level for preset times and performs pre-filtering calculation, if the continuously collected input level exceeds a preset error range, the MCU marks the input level as a failure voltage, the MCU marks the output state as 0 and then re-collects the input signal, and if the continuously collected input level is within the preset error range, the MCU marks the input level as a valid voltage.
In this embodiment, in order to prevent erroneous operation of the input signal due to electrical jitter caused by human factors or other factors, a pre-filter calculation is performed when the input signal is confirmed. The pre-filtering calculation will continuously collect N times of voltage, which is the current effective voltage if the N times of voltage are the same as each other on average.
Then, the MCU acquires preset external factors and the working state of the execution part, if the external factors do not meet the preset conditions or the working state of the execution part is abnormal, the MCU marks the output state as 0, meanwhile, the MCU displays the external factors which do not meet the preset conditions or the execution part with the abnormal working state through the display module to prompt the fault phenomenon, and if the external conditions meet the preset conditions and the working state of the execution part is normal, the MCU marks the output state as 1.
In this embodiment, since the controller is connected to the complete machine system, after the input conditions are satisfied, the control system will collect some other data at the same time, such as temperature, oil pressure, battery voltage, etc., and when these conditions are abnormal, the control will not be able to be output. The output will control the current drive execution unit according to the current MAP only if all conditions are satisfied at the same time.
Then, the MCU detects the output state, if the output state is 0, the driving module is closed, the hydraulic execution part does not act, and if the output state is 1, the driving module is opened, and the MCU acquires the information of a preset driving circuit in the driving module.
In the embodiment, the driving module adopts half-bridge driving, different control programs are written according to the connection method (high side or low side) of different hydraulic execution components, the hardware is not distinguished, meanwhile, the driving module can select open-loop or closed-loop control, and when the execution element has short circuit or other faults, the control element can automatically protect, so that unrecoverable faults caused by the control unit are avoided.
If the driving of the open-loop circuit is performed, the MCU controls the driving module to drive the hydraulic execution component to act by adopting an open-loop control method, wherein when an input signal is in an effective level, the MCU transmits a corresponding control current to the driving module according to an output current response MAP. However, when the impedance of the hydraulic execution part is changed due to external factors, the driving current can be changed along with the impedance change of the hydraulic execution part, if the impedance of the hydraulic execution part is increased, the driving current can be reduced, otherwise, the impedance of the hydraulic execution part is reduced, and the driving current is increased.
If the driving is performed by a closed-loop circuit, the MCU controls the driving module to drive the hydraulic execution part to act by adopting a closed-loop control method, wherein when an input signal is an effective voltage, the MCU transmits a corresponding control current to the driving module according to an output current response MAP, the MCU outputs a PWM wave signal to the driving module, the MCU calculates a PWM wave output corresponding duty ratio according to the magnitude of the control current, and the driving module amplifies the waveform of the corresponding duty ratio output by the MCU into the required voltage of the hydraulic execution part. In the control process, the closed loop circuit can collect the current driving current in real time and convert the current driving current into voltage to be fed back to the MCU, the MCU adjusts the PWM wave output duty ratio according to the feedback voltage, the voltage of the hydraulic execution part is changed, and finally the driving current output by the driving module is kept the same as the control current. Based on the closed-loop control method, the driving current output by the driving module does not change along with the change of the load, and the hydraulic execution component control system can continuously and stably control the action of the hydraulic execution component.
In this embodiment, the output current response MAP refers to a functional relationship between an effective level and an output current, and the abscissa of the output current response MAP is the effective level and the ordinate is the control current, where a specific functional relationship needs to be preset.
While the invention has been described in terms of preferred embodiments, it is not intended to be limiting. Those skilled in the art will appreciate that various modifications and adaptations can be made without departing from the spirit and scope of the present invention. Accordingly, the scope of the invention is defined by the appended claims.