A control method for a hydraulic transmission

Abstract

The invention discloses a control method for a hydraulic transmission, and relates to the technical field of hydraulic transmission control for forklifts; the invention establishes a comprehensive monitoring, analysis and diagnosis execution mechanism. The operating parameters such as hydraulic oil temperature and pressure are monitored in real time, the hydraulic oil temperature state ratio, oil temperature change rate, and pressure state ratio indicators are calculated, and a comprehensive analysis is performed to obtain a forklift warning index, which is compared with a preset threshold value. If the threshold value is higher than the threshold value, a warning signal is triggered, and a graded warning is given according to the warning degree value. A general warning reminds the driver to return to the factory for inspection and maintenance, and a serious warning reminds the driver to stop the machine immediately and notify the nearest maintenance personnel, thereby realizing active fault warning and processing, timely discovering potential problems, avoiding equipment failure deterioration, reducing maintenance costs, reducing downtime caused by failures, improving forklift reliability and availability, and ensuring the continuity of production operations.

Description

Technical Field

[0001] The invention relates to the technical field of forklift hydraulic transmission control, in particular to a control method of a hydraulic transmission. Background Art

[0002] Internal combustion forklifts play an important role in logistics and other fields. The performance of their hydraulic transmissions directly affects the operating convenience and safety of the forklifts.

[0003] However, the control method used in the hydraulic transmission in the prior art still has the following deficiencies in practical application:

[0004] Most of the existing technologies use solenoid valve control, and the solenoid valve current cannot be regulated, and the current cannot be adjusted and controlled in a targeted manner according to the specific driving state of the vehicle;

[0005] In addition, there is a lack of effective real-time monitoring and early warning mechanisms during vehicle driving, and abnormal changes in key parameters such as hydraulic oil temperature and pressure cannot be detected in time, which can easily lead to further deterioration of equipment failures and increase maintenance costs and downtime.

[0006] To this end, a control method for a hydraulic transmission is introduced Summary of the invention

[0007] The purpose of the present invention is to solve the problem mentioned in the background technology and to provide a control method for a hydraulic transmission.

[0008] The object of the present invention can be achieved by the following technical solution: A control method of a hydraulic transmission, comprising:

[0009] Initialization operation: Initialize the pre-installed groups of sensors, proportional valves and controllers;

[0010] Dynamic control: Real-time acquisition of vehicle driving status, and targeted control of the gearbox based on the vehicle driving status; the vehicle driving status includes starting status, forward reversing status, reverse reversing status and ramp status;

[0011] Monitoring and analysis: During the driving process of the vehicle, the operating parameters of the gearbox within the set time interval are monitored and evaluated in real time, so as to obtain the forklift warning index cfg of the vehicle within the set time interval of the current driving process; based on the comparison result of the forklift warning index cfg within the set time interval of the current driving process of the vehicle, the warning signal is selectively triggered; the operating parameters include hydraulic oil temperature and hydraulic oil pressure;

[0012] Diagnostic execution: Execute the corresponding steps when the early warning signal is triggered.

[0013] As a preferred embodiment of the present invention, the gearbox is controlled in a targeted manner according to the driving state of the vehicle. If the driving state is a starting state, the specific control steps are:

[0014] When the vehicle is in the starting state, 100% current is applied to the forward proportional valve according to the pre-set strategy;

[0015] After the application is completed, a nonlinearly changing current is applied to the forward proportional valve based on the set time zone; the set time zone is divided into three sub-time zones; namely, the first sub-time zone, the second sub-time zone and the third sub-time zone, and the current reduction values ​​corresponding to the first sub-time zone and the second sub-time zone are set respectively; when entering the first sub-time zone or the second sub-time zone, the forward proportional valve is controlled according to the set current reduction value;

[0016] After entering the third sub-time zone, the load weight of the vehicle is obtained, and the load weight value ranges corresponding to each group of load weights are preset, and each group of load weight value ranges is set to correspond to a current adaptation value; the load weight of the vehicle is matched with the preset load weight value ranges, so as to obtain the current adaptation value of the forward proportional valve of the vehicle after entering the third time zone.

[0017] As a preferred embodiment of the present invention, the gearbox is controlled in a targeted manner according to the driving state of the vehicle. If the driving state is a forward reversing state or a reverse reversing state, the specific control steps are:

[0018] When the vehicle is in the forward reversing state, the reverse proportional valve is opened according to a preset strategy, and the current of the reverse proportional valve is increased at a preset rate; at the same time, the current of the forward proportional valve is reduced at the same set rate, and the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped;

[0019] When the vehicle is in the reverse direction switching state, the forward proportional valve is opened according to the pre-set strategy, and the current of the forward proportional valve is increased at a set rate; at the same time, the current of the reverse proportional valve is reduced at the same set rate. At the same time, the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped.

[0020] As a preferred embodiment of the present invention, the gearbox is controlled in a targeted manner according to the driving state of the vehicle. If the driving state is a slope state, the specific control steps are:

[0021] The specific types of ramp states are divided into ramp stop state and ramp start state; when the vehicle driving state is the ramp stop state, the vehicle's inclination angle and load weight data are obtained, and the data pair corresponding to the ramp stop state is constructed, that is, (vehicle inclination angle, load weight); when the vehicle driving state is the ramp start state, the driver steps on the accelerator at this time, the vehicle's throttle opening, vehicle inclination angle and load weight are obtained, and the data pair corresponding to the ramp start state is constructed, that is, (throttle opening, vehicle inclination angle, load weight);

[0022] Based on the specific type of the vehicle ramp state, the vehicle data pairs are input into the corresponding constructed database for matching, wherein the constructed database includes a ramp stop state database and a ramp start state database, and the database includes groups of reference data pairs, each group of reference data pairs in the ramp stop state database corresponds to a vehicle inclination angle value range and a load weight value range, that is, (vehicle inclination angle range, load weight range), and each group of reference data pairs in the ramp start state database corresponds to a throttle opening range, a vehicle inclination angle value range and a load weight value range, that is, (throttle opening range, vehicle inclination angle range, load weight range); each group of reference data pairs is set to correspond to an adjustment range of a proportional valve current;

[0023] After matching the vehicle data pair with the corresponding reference data pair, the proportional valve current adjustment range corresponding to the current ramp state of the vehicle is obtained, and the proportional valve current is automatically adjusted to within the matched proportional valve current adjustment range.

[0024] As a preferred embodiment of the present invention, the hydraulic oil temperature of the gearbox within a set time interval is monitored and evaluated in real time, specifically:

[0025] Obtaining hydraulic oil temperature values ​​of the vehicle at each time point within a set time interval; calculating an average of the hydraulic oil temperature values ​​of the vehicle within the set time interval as a comprehensive value of the hydraulic oil temperature of the vehicle within the set time interval;

[0026] Preset reference hydraulic oil temperature values ​​corresponding to different driving time ranges of the vehicle, and extract the corresponding reference hydraulic oil temperature value based on the driving time range corresponding to the current set time interval of the vehicle;

[0027] The ratio of the comprehensive value of the hydraulic oil temperature to the reference hydraulic oil temperature value is calculated to obtain the hydraulic oil temperature state ratio of the vehicle within a set time interval; that is, it is calculated by the comprehensive value of the hydraulic oil temperature / the reference hydraulic oil temperature value;

[0028] Extract the hydraulic oil temperature value of the vehicle at each time point within the set time interval, and calculate the oil temperature change rate of the hydraulic oil temperature values ​​at adjacent time points;

[0029] The reference threshold rate corresponding to the preset oil temperature change rate is compared with the preset reference threshold rate respectively. If a group of oil temperature change rates is higher than the preset reference threshold rate, the oil temperature change rate higher than the reference threshold rate is marked as an abnormal change rate, and the difference between the abnormal change rate and the reference threshold rate is calculated and recorded as the abnormal difference rate;

[0030] The number of statistical abnormal change rates is recorded as abnormal variables; the average of the abnormal difference rates of each group is calculated to obtain the abnormal average rate; the abnormal variables and abnormal average rate are marked as q1 and q2 respectively;

[0031] According to the formula The abnormal variable q1 and the abnormal average rate q2 within the set time interval are weighted to obtain the oil temperature trend index qk within the set time interval; and are the preset allowed number of abnormalities and allowed average rate of abnormalities respectively; a1 and a2 are the impact weight factors corresponding to the abnormal variable q1 and the abnormal average rate q2 respectively;

[0032] The intervals of each group of indexes corresponding to the preset oil temperature trend index are set to correspond to a state additional coefficient respectively; the oil temperature trend index qk of the vehicle in the set time interval is matched with the intervals of each group of indexes, and the state additional coefficient corresponding to the hydraulic oil temperature state ratio of the vehicle in the set time interval is obtained;

[0033] The hydraulic oil temperature state ratio of the vehicle within the set time interval is multiplied by the matched state additional coefficient to obtain the hydraulic oil temperature evaluation index of the vehicle within the set time interval.

[0034] As a preferred embodiment of the present invention, the hydraulic oil pressure of the gearbox within a set time interval is monitored and evaluated in real time, specifically:

[0035] The hydraulic oil pressure of the vehicle at each time point within a set time interval is obtained and the average is calculated to obtain the hydraulic oil pressure average value, the maximum pressure resistance value of the hydraulic oil pressure is preset, and based on the preset maximum pressure resistance value, the time points at which the hydraulic oil pressure at each time point is higher than the maximum pressure resistance value are identified, and the number of identified time points is counted and recorded as the overpressure number;

[0036] The ratio between the hydraulic oil pressure average and the maximum pressure resistance is calculated to obtain the pressure state ratio of the vehicle within a set time interval; that is, it is calculated by the hydraulic oil pressure average / maximum pressure resistance;

[0037] The intervals of the numbers of each group corresponding to the preset overpressure quantity are set to correspond to a pressure additional coefficient for each interval of the numbers of each group; the overpressure quantity of the vehicle in the set time interval is matched with the intervals of the numbers of each group, and the pressure additional coefficient corresponding to the pressure state ratio of the vehicle in the set time interval is obtained;

[0038] The pressure state ratio of the vehicle within the set time interval is multiplied by the matched pressure additional coefficient to obtain the hydraulic oil pressure evaluation index of the vehicle within the set time interval.

[0039] As a preferred embodiment of the present invention, based on the comparison result of the forklift warning index cfg within a set time interval during the current driving process of the vehicle, a warning signal is selectively triggered, specifically:

[0040] The weight coefficients corresponding to the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index are set respectively, and the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index within the set time interval are multiplied by the set weight coefficients respectively, and then the sum is obtained to obtain the forklift warning index cfg of the vehicle within the set time interval;

[0041] The forklift warning index cfg of the vehicle within the set time interval is compared with the preset warning index threshold. If the forklift warning index cfg of the vehicle within the set time interval is higher than the preset warning index threshold, the warning signal is triggered.

[0042] As a preferred implementation of the present invention, corresponding steps are performed when the warning signal is triggered, specifically:

[0043] S1: extract the forklift warning index cfg corresponding to the vehicle triggering the warning signal, and calculate the difference with the preset warning index threshold to obtain the warning degree value; set the degree reference value corresponding to the warning degree value. If the warning degree value is lower than the set degree reference value, trigger the general warning signal to remind the driver to stop the vehicle and return to the factory for inspection and maintenance as soon as possible. If the warning degree value is higher than the set degree reference value, trigger the serious warning signal and execute step S2;

[0044] S2: Remind the driver to stop the vehicle as soon as possible, and at the same time obtain the location of the forklift corresponding to the triggering of the serious warning signal, and send it to the maintenance personnel closest to the forklift.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention adopts proportional valve control to replace the existing solenoid valve control, and accurately controls according to different driving states of the vehicle to make the gear shift smoother and the power output stable, thereby improving the comfort of forklift operation, reducing the damage to vehicle components caused by gear shift impact, extending the service life of the vehicle, and improving work efficiency;

[0047] The present invention establishes a comprehensive monitoring, analysis and diagnosis execution mechanism. It monitors the operating parameters such as hydraulic oil temperature and pressure in real time, calculates the hydraulic oil temperature state ratio, oil temperature change rate, and pressure state ratio indicators, and performs comprehensive analysis to obtain the forklift warning index, which is compared with the preset threshold value. If it is higher than the threshold value, the warning signal is triggered. According to the warning degree value, the warning is graded. The general warning reminds the driver to return to the factory for inspection and maintenance, and the serious warning reminds the driver to stop the machine immediately and notify the nearest maintenance personnel. Active fault warning and processing are realized, potential problems can be discovered in time, equipment failures can be avoided, maintenance costs can be reduced, downtime caused by failures can be reduced, the reliability and availability of the forklift can be improved, and the continuity of production operations can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0049] Figure 1 It is a principle block diagram of the present invention. DETAILED DESCRIPTION

[0050] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] See also Figure 1 As shown, a control method for a hydraulic transmission includes:

[0052] Initialization operation: After starting the pre-built forklift hydraulic transmission control system, perform initialization operations on the pre-installed groups of sensors, proportional valves and controllers; each group of sensors includes inclination sensors and vehicle speed sensors, etc.;

[0053] It should be noted that initialization operations include, for example, calibrating the inclination sensor to ensure that it can accurately detect the levelness of the vehicle body and provide precise angle data for subsequent slope control; setting the initial current of the proportional valve to zero or a preset initial value to put the clutch in an initial state, ready to receive control instructions.

[0054] Dynamic control: Real-time acquisition of vehicle driving status, and targeted control of the gearbox based on the vehicle driving status; the vehicle driving status includes starting status, forward reversing status, reverse reversing status and ramp status;

[0055] Specifically:

[0056] Starting state: When the vehicle is in the starting state, 100% current is applied to the forward proportional valve according to the pre-set strategy;

[0057] It should be noted that the strategy is a "hard kick". After applying 100% current to the forward proportional valve, a large amount of hydraulic oil quickly flows into the forward clutch, causing the clutch to quickly enter the initial engagement state, providing a strong initial driving force for the vehicle to overcome static inertia;

[0058] After the application is completed, a nonlinearly changing current is applied to the forward proportional valve based on the set time zone; the time zone is set to 5s; the set time zone is divided into three sub-time zones; namely, 0-1s; 1-3s; 3-5s; namely, the first sub-time zone, the second sub-time zone and the third sub-time zone, and the current reduction values ​​corresponding to the first sub-time zone and the second sub-time zone are set respectively; 0-1S is set to reduce the current from 100% to 80%, and 1-3S is set to reduce the current from 80% to 60%; when entering the first sub-time zone or the second sub-time zone, the forward proportional valve is controlled according to the set current reduction value;

[0059] After entering the third sub-time zone, the load weight of the vehicle is obtained, and the load weight value ranges corresponding to each group of load weights are preset, and each group of load weight value ranges is set to correspond to a current adaptation value; the current adaptation value range is set at 40%-50%; the load weight of the vehicle is matched with the preset load weight value ranges, so as to obtain the current adaptation value of the forward proportional valve of the vehicle after entering the third time zone; the higher the load weight, the higher the corresponding matching current adaptation value;

[0060] It should be noted that within the set time zone (0-5 seconds), a nonlinear current value is applied to the proportional valve; within 0-1 second, the current value is rapidly reduced from 100% to 80%, so that the clutch begins to engage gradually and smoothly, and the vehicle begins to move slowly; within 1-3 seconds, the current value is further reduced to 60%, and the vehicle acceleration process is smoother; within 3-5 seconds, the current value is determined according to the vehicle load and stabilized between 40%-50% (close to 40% when lightly loaded, close to 50% when heavily loaded), ensuring that the vehicle starts and moves smoothly and quickly, while avoiding the impact when starting and ensuring ride comfort;

[0061] Forward reversing state: When the vehicle is in the forward reversing state, that is, when the vehicle needs to change direction during the forward process, the driver switches the gear switch from the forward direction to the reverse direction; the reverse proportional valve is opened according to the pre-set strategy, and the current of the reverse proportional valve is increased at a set rate, that is, 5%-8% per second; at the same time, the current of the forward proportional valve is reduced at the same set rate, and the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped; the speed range is close to zero;

[0062] It should be noted that when the vehicle needs to change direction during the forward movement, the driver switches the gear switch from forward to reverse; the gear switching signal is immediately received, and then according to the pre-set strategy, the reverse proportional valve is quickly opened, and its control current is gradually increased at a rate of 5%-8% per second (adjustable according to different vehicle models and working conditions). At the same time, the current of the forward proportional valve is gradually reduced at a rate of 5%-8% per second; in this process, the vehicle speed sensor continuously monitors the vehicle speed change. When the vehicle speed decreases to the preset speed range, it indicates that the vehicle has decelerated steadily. At this time, the increase of the reverse proportional valve current and the decrease of the forward proportional valve current are completed, and the vehicle is smoothly reversed to the reverse state.

[0063] Reverse reversing state: When the vehicle is in the reverse reversing state; when the vehicle needs to be reversed to forward during the reverse process, the driver operates the gear switch from the reverse direction to the forward direction; the forward proportional valve is opened according to the pre-set strategy, and the current of the forward proportional valve is increased at a set rate; that is, it increases by 6%-9% per second; at the same time, the current of the reverse proportional valve is reduced at the same set rate, and the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped;

[0064] It should be noted that the vehicle speed is also monitored by the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the forward proportional valve current is increased and the reverse proportional valve current is reduced, so that the vehicle can smoothly switch to the forward state. Due to the different gear ratios of the forward and reverse gearboxes, different proportional valve current control strategies are used for the two directions to ensure the best switching effect.

[0065] Slope state: The specific types of slope states are slope stop state and slope start state. When the inclination sensor detects that the inclination angle of the vehicle body is greater than the preset threshold angle, it is determined to be a slope state. When the accelerator is pressed, it is a slope start state, and when the accelerator is not pressed, it is a slope stop state. When the vehicle is in the slope stop state, the inclination angle and load weight data of the vehicle are obtained, and the data pair corresponding to the slope stop state is constructed, that is, (vehicle inclination angle, load weight); when the vehicle is in the slope start state, the driver presses the accelerator, and the throttle opening, vehicle inclination angle and load weight of the vehicle are obtained, and the data pair corresponding to the slope start state is constructed, that is, (throttle opening, vehicle inclination angle, load weight);

[0066] Based on the specific type of the vehicle ramp state, the vehicle data pairs are input into the corresponding constructed database for matching, wherein the constructed database includes a ramp stop state database and a ramp start state database, and the database includes groups of reference data pairs, each group of reference data pairs in the ramp stop state database corresponds to a vehicle inclination angle value range and a load weight value range, that is, (vehicle inclination angle range, load weight range), and each group of reference data pairs in the ramp start state database corresponds to a throttle opening range, a vehicle inclination angle value range and a load weight value range, that is, (throttle opening range, vehicle inclination angle range, load weight range); each group of reference data pairs is set to correspond to an adjustment range of a proportional valve current;

[0067] After matching the vehicle data pair with the corresponding reference data pair, the proportional valve current adjustment range corresponding to the current ramp state of the vehicle is obtained, and the proportional valve current is automatically adjusted to within the matched proportional valve current adjustment range;

[0068] It should be noted that if the vehicle is stopped on a slope and the gear is in the forward or reverse gear, the proportional valve current is automatically adjusted according to the vehicle body inclination angle and load weight to increase the clutch engagement, so that the vehicle is in a stable parking state and effectively prevent the occurrence of sliding down the slope;

[0069] When the vehicle needs to start on a slope, the driver steps on the accelerator and the proportional valve current is automatically adjusted according to the accelerator opening, vehicle body inclination and load weight to ensure a smooth start of the vehicle.

[0070] Monitoring and analysis: During the driving process of the vehicle, the operating parameters of the gearbox within the set time interval are monitored and evaluated in real time, so as to obtain the forklift warning index cfg of the vehicle within the set time interval of the current driving process; based on the comparison result of the forklift warning index cfg within the set time interval of the current driving process of the vehicle, the warning signal is selectively triggered; the operating parameters include hydraulic oil temperature and hydraulic oil pressure;

[0071] Specifically:

[0072] Using the temperature sensor pre-installed in the hydraulic oil circulation system, the hydraulic oil temperature value of the vehicle at each time point within the set time interval is obtained;

[0073] Calculate the average value of the hydraulic oil temperature of the vehicle in the set time interval as the comprehensive value of the hydraulic oil temperature of the vehicle in the set time interval;

[0074] Preset reference hydraulic oil temperature values ​​corresponding to different driving time ranges of the vehicle, and extract the corresponding reference hydraulic oil temperature value based on the driving time range corresponding to the current set time interval of the vehicle;

[0075] The ratio of the comprehensive value of the hydraulic oil temperature to the reference hydraulic oil temperature value is calculated to obtain the hydraulic oil temperature state ratio of the vehicle within a set time interval; that is, it is calculated by the comprehensive value of the hydraulic oil temperature / the reference hydraulic oil temperature value;

[0076] Extract the hydraulic oil temperature value of the vehicle at each time point within the set time interval, and calculate the oil temperature change rate of the hydraulic oil temperature values ​​at adjacent time points, that is, subtract the hydraulic oil temperature value on the right from the hydraulic oil temperature value on the left at adjacent time points, and divide the calculated difference by the interval length of adjacent time points;

[0077] The reference threshold rate corresponding to the preset oil temperature change rate is compared with the preset reference threshold rate respectively. If a group of oil temperature change rates is higher than the preset reference threshold rate, the oil temperature change rate higher than the reference threshold rate is marked as an abnormal change rate, and the difference between the abnormal change rate and the reference threshold rate is calculated and recorded as the abnormal difference rate;

[0078] The number of statistical abnormal change rates is recorded as abnormal variables; the average of the abnormal difference rates of each group is calculated to obtain the abnormal average rate; the abnormal variables and abnormal average rate are marked as q1 and q2 respectively;

[0079] According to the formula The abnormal variable q1 and the abnormal average rate q2 within the set time interval are weighted to obtain the oil temperature trend index qk within the set time interval; and are the preset allowed number of abnormalities and allowed average rate of abnormalities respectively; a1 and a2 are the impact weight factors corresponding to the abnormal variable q1 and the abnormal average rate q2 respectively;

[0080] The intervals of each group of indexes corresponding to the preset oil temperature trend index are set to correspond to a state additional coefficient respectively; the state additional coefficient range is set to 1.137-1.358, and the higher the oil temperature trend index qk is, the higher the corresponding state additional coefficient is; the oil temperature trend index qk of the vehicle in the set time interval is matched with the intervals of each group of indexes, and the state additional coefficient corresponding to the hydraulic oil temperature state ratio of the vehicle in the set time interval is obtained;

[0081] The hydraulic oil temperature state ratio of the vehicle within the set time interval is multiplied by the matched state additional coefficient, thereby obtaining the hydraulic oil temperature evaluation index of the vehicle within the set time interval;

[0082] It should be noted that the hydraulic oil temperature assessment index combines the hydraulic oil temperature state ratio and the state additional coefficient. The state additional coefficient is dynamically adjusted according to the oil temperature trend index, so that the assessment result can better reflect the actual risk level of the hydraulic oil temperature.

[0083] The hydraulic oil pressure of the vehicle at each time point within a set time interval is obtained by means of a pressure sensor installed in the hydraulic oil pipeline, and the average is calculated to obtain the hydraulic oil pressure average value, and the maximum pressure resistance value of the hydraulic oil pressure is preset. Based on the preset maximum pressure resistance value, the time points at which the hydraulic oil pressure at each time point is higher than the maximum pressure resistance value are identified, and the number of identified time points is counted and recorded as the overpressure number;

[0084] The ratio between the hydraulic oil pressure average and the maximum pressure resistance is calculated to obtain the pressure state ratio of the vehicle within a set time interval; that is, it is calculated by the hydraulic oil pressure average / maximum pressure resistance;

[0085] The intervals of the numbers of each group corresponding to the preset overpressure number are set to correspond to a pressure additional coefficient for each interval of the number of each group; the range of the pressure additional coefficient is set to 1.118-1.278, and the greater the number of overpressures, the higher the corresponding pressure additional coefficient; the overpressure number of the vehicle in the set time interval is matched with the intervals of the numbers of each group, and the pressure additional coefficient corresponding to the pressure state ratio of the vehicle in the set time interval is obtained;

[0086] The pressure state ratio of the vehicle in the set time interval is multiplied by the matched pressure additional coefficient, so as to obtain the hydraulic oil pressure evaluation index of the vehicle in the set time interval;

[0087] It should be noted that the pressure additional coefficient is set according to the interval of the overpressure number, so that the hydraulic oil pressure assessment index can quantify the degree of pressure risk. The more overpressure there is, the higher the pressure additional coefficient is, which leads to a corresponding increase in the assessment index; this realizes the classification of hydraulic oil pressure risks, and can intuitively understand the severity of the pressure situation so as to take appropriate measures.

[0088] The weight coefficients corresponding to the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index are set respectively, and the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index within the set time interval are multiplied by the set weight coefficients respectively, and then the sum is obtained to obtain the forklift warning index cfg of the vehicle within the set time interval;

[0089] Compare the forklift warning index cfg of the vehicle within the set time interval with the preset warning index threshold. If the forklift warning index cfg of the vehicle within the set time interval is higher than the preset warning index threshold, a warning signal is triggered;

[0090] Diagnostic execution: execute the corresponding steps when the warning signal is triggered;

[0091] Specifically:

[0092] S1: extract the forklift warning index cfg corresponding to the vehicle triggering the warning signal, and calculate the difference with the preset warning index threshold to obtain the warning degree value; set the degree reference value corresponding to the warning degree value. If the warning degree value is lower than the set degree reference value, trigger the general warning signal to remind the driver to stop the vehicle and return to the factory for inspection and maintenance as soon as possible. If the warning degree value is higher than the set degree reference value, trigger the serious warning signal and execute step S2;

[0093] S2: Remind the driver to stop the vehicle as soon as possible, and at the same time obtain the location of the forklift corresponding to the triggering of the serious warning signal, and send it to the maintenance personnel closest to the forklift;

[0094] It should be noted that by calculating the warning level and comparing it with the reference level, the warning signal can be accurately graded. Different levels of warning methods are used for potential problems of different severity, avoiding the situation where a single warning method may cause the driver to pay insufficient attention to the problem or be overly nervous.

[0095] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A control method for a hydraulic transmission, characterized in that: include: Initialization operation: Initialize the pre-installed groups of sensors, proportional valves and controllers; Dynamic control: Real-time acquisition of vehicle driving status, and targeted control of the gearbox based on the vehicle driving status; the vehicle driving status includes starting status, forward reversing status, reverse reversing status and ramp status; Monitoring and analysis: During the driving process of the vehicle, the operating parameters of the gearbox within the set time interval are monitored and evaluated in real time, so as to obtain the forklift warning index cfg of the vehicle within the set time interval of the current driving process; Based on the comparison result of the forklift warning index cfg within the set time interval during the current driving process of the vehicle, the warning signal is selectively triggered; The operating parameters include hydraulic oil temperature and hydraulic oil pressure; Diagnostic execution: Execute the corresponding steps when the early warning signal is triggered.

2. A control method for a hydraulic transmission according to claim 1, characterized in that: The gearbox is controlled in a targeted manner according to the vehicle's driving state. If the driving state is the starting state, the specific control steps are: When the vehicle is in the starting state, 100% current is applied to the forward proportional valve according to the pre-set strategy; After the application is completed, a nonlinearly changing current is applied to the forward proportional valve based on the set time zone; the set time zone is divided into three sub-time zones; namely, the first sub-time zone, the second sub-time zone and the third sub-time zone, and the current reduction values ​​corresponding to the first sub-time zone and the second sub-time zone are set respectively; when entering the first sub-time zone or the second sub-time zone, the forward proportional valve is controlled according to the set current reduction value; After entering the third sub-time zone, the load weight of the vehicle is obtained, and the load weight value ranges corresponding to each group of load weights are preset, and each group of load weight value ranges is set to correspond to a current adaptation value; the load weight of the vehicle is matched with the preset load weight value ranges, so as to obtain the current adaptation value of the forward proportional valve of the vehicle after entering the third time zone.

3. A control method for a hydraulic transmission according to claim 2, characterized in that: The gearbox is controlled in a targeted manner according to the vehicle driving state. If the driving state is the forward reversing state or the reverse reversing state, the specific control steps are as follows: When the vehicle is in the forward reversing state, the reverse proportional valve is opened according to a preset strategy, and the current of the reverse proportional valve is increased at a preset rate; at the same time, the current of the forward proportional valve is reduced at the same set rate, and the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped; When the vehicle is in the reverse direction switching state, the forward proportional valve is opened according to the pre-set strategy, and the current of the forward proportional valve is increased at a set rate; at the same time, the current of the reverse proportional valve is reduced at the same set rate. At the same time, the vehicle speed is monitored in real time through the vehicle speed sensor. When the vehicle speed reaches the preset speed range, the current adjustment of the reverse proportional valve and the forward proportional valve is stopped.

4. A control method for a hydraulic transmission according to claim 3, characterized in that: The gearbox is controlled in a targeted manner according to the vehicle's driving state. If the driving state is a slope, the specific control steps are as follows: The specific types of ramp states are divided into ramp stop state and ramp start state; when the vehicle driving state is the ramp stop state, the vehicle's inclination angle and load weight data are obtained, and the data pair corresponding to the ramp stop state is constructed, that is, (vehicle inclination angle, load weight); when the vehicle driving state is the ramp start state, the driver steps on the accelerator at this time, the vehicle's throttle opening, vehicle inclination angle and load weight are obtained, and the data pair corresponding to the ramp start state is constructed, that is, (throttle opening, vehicle inclination angle, load weight); Based on the specific type of the vehicle ramp state, the vehicle data pairs are input into the corresponding constructed database for matching, wherein the constructed database includes a ramp stop state database and a ramp start state database, and the database includes groups of reference data pairs, each group of reference data pairs in the ramp stop state database corresponds to a vehicle inclination angle value range and a load weight value range, that is, (vehicle inclination angle range, load weight range), and each group of reference data pairs in the ramp start state database corresponds to a throttle opening range, a vehicle inclination angle value range and a load weight value range, that is, (throttle opening range, vehicle inclination angle range, load weight range); each group of reference data pairs is set to correspond to an adjustment range of a proportional valve current; After matching the vehicle data pair with the corresponding reference data pair, the proportional valve current adjustment range corresponding to the current ramp state of the vehicle is obtained, and the proportional valve current is automatically adjusted to within the matched proportional valve current adjustment range.

5. A control method for a hydraulic transmission according to claim 4, characterized in that: Real-time monitoring and evaluation of the gearbox hydraulic oil temperature within a set time interval, specifically: Obtaining hydraulic oil temperature values ​​of the vehicle at each time point within a set time interval; calculating an average of the hydraulic oil temperature values ​​of the vehicle within the set time interval as a comprehensive value of the hydraulic oil temperature of the vehicle within the set time interval; Preset reference hydraulic oil temperature values ​​corresponding to different driving time ranges of the vehicle, and extract the corresponding reference hydraulic oil temperature value based on the driving time range corresponding to the current set time interval of the vehicle; The ratio of the comprehensive value of the hydraulic oil temperature to the reference hydraulic oil temperature value is calculated to obtain the hydraulic oil temperature state ratio of the vehicle within a set time interval; that is, it is calculated by the comprehensive value of the hydraulic oil temperature / the reference hydraulic oil temperature value; Extract the hydraulic oil temperature value of the vehicle at each time point within the set time interval, and calculate the oil temperature change rate of the hydraulic oil temperature values ​​at adjacent time points; The reference threshold rate corresponding to the preset oil temperature change rate is compared with the preset reference threshold rate respectively. If a group of oil temperature change rates is higher than the preset reference threshold rate, the oil temperature change rate higher than the reference threshold rate is marked as an abnormal change rate, and the difference between the abnormal change rate and the reference threshold rate is calculated and recorded as the abnormal difference rate; The number of statistical abnormal change rates is recorded as abnormal variables; the average of the abnormal difference rates of each group is calculated to obtain the abnormal average rate; the abnormal variables and abnormal average rate are marked as q1 and q2 respectively; According to the formula The abnormal variable q1 and the abnormal average rate q2 within the set time interval are weighted to obtain the oil temperature trend index qk within the set time interval; and are the preset allowed number of abnormalities and allowed average rate of abnormalities respectively; a1 and a2 are the impact weight factors corresponding to the abnormal variable q1 and the abnormal average rate q2 respectively; The intervals of each group of indexes corresponding to the preset oil temperature trend index are set to correspond to a state additional coefficient respectively; the oil temperature trend index qk of the vehicle in the set time interval is matched with the intervals of each group of indexes, and the state additional coefficient corresponding to the hydraulic oil temperature state ratio of the vehicle in the set time interval is obtained; The hydraulic oil temperature state ratio of the vehicle within the set time interval is multiplied by the matched state additional coefficient to obtain the hydraulic oil temperature evaluation index of the vehicle within the set time interval.

6. A control method for a hydraulic transmission according to claim 5, characterized in that: Real-time monitoring and evaluation of the gearbox hydraulic oil pressure within a set time interval, specifically: The hydraulic oil pressure of the vehicle at each time point within a set time interval is obtained and the average is calculated to obtain the hydraulic oil pressure average value, the maximum pressure resistance value of the hydraulic oil pressure is preset, and based on the preset maximum pressure resistance value, the time points at which the hydraulic oil pressure at each time point is higher than the maximum pressure resistance value are identified, and the number of identified time points is counted and recorded as the overpressure number; The ratio between the hydraulic oil pressure average and the maximum pressure resistance is calculated to obtain the pressure state ratio of the vehicle within a set time interval; that is, it is calculated by the hydraulic oil pressure average / maximum pressure resistance; The intervals of the numbers of each group corresponding to the preset overpressure quantity are set to correspond to a pressure additional coefficient for each interval of the numbers of each group; the overpressure quantity of the vehicle in the set time interval is matched with the intervals of the numbers of each group, and the pressure additional coefficient corresponding to the pressure state ratio of the vehicle in the set time interval is obtained; The pressure state ratio of the vehicle within the set time interval is multiplied by the matched pressure additional coefficient to obtain the hydraulic oil pressure evaluation index of the vehicle within the set time interval.

7. A control method for a hydraulic transmission according to claim 6, characterized in that: Based on the comparison result of the forklift warning index cfg within the set time interval during the current driving process of the vehicle, the warning signal is selectively triggered, specifically: The weight coefficients corresponding to the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index are set respectively, and the hydraulic oil temperature evaluation index and the hydraulic oil pressure evaluation index within the set time interval are multiplied by the set weight coefficients respectively, and then the sum is obtained to obtain the forklift warning index cfg of the vehicle within the set time interval; The forklift warning index cfg of the vehicle within the set time interval is compared with the preset warning index threshold. If the forklift warning index cfg of the vehicle within the set time interval is higher than the preset warning index threshold, the warning signal is triggered.

8. A control method for a hydraulic transmission according to claim 7, characterized in that: When the warning signal is triggered, the corresponding steps are executed, specifically: S1: extract the forklift warning index cfg corresponding to when the vehicle triggers the warning signal, and calculate the difference with the preset warning index threshold to obtain the warning degree value; A degree reference value corresponding to the warning degree value is set. If the warning degree value is lower than the set degree reference value, a general warning signal is triggered to remind the driver to stop the vehicle and return to the factory for inspection and maintenance as soon as possible. If the warning degree value is higher than the set degree reference value, a serious warning signal is triggered and step S2 is executed; S2: Remind the driver to stop the vehicle as soon as possible, and at the same time obtain the location of the forklift corresponding to the triggering of the serious warning signal, and send it to the maintenance personnel closest to the forklift.

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