CN-121974272-A - Self-adaptive low-margin forklift overload control system and method

CN121974272ACN 121974272 ACN121974272 ACN 121974272ACN-121974272-A

Abstract

The invention discloses an overload control system and method of a self-adaptive low-margin forklift, which belong to the field of forklifts and comprise a pressure detection unit, a load adjusting unit, a control unit and a control unit, wherein the pressure detection unit is used for detecting working pressure of a lifting cylinder of the forklift in real time, the load adjusting unit comprises a movable load body and an actuating mechanism, the control unit is respectively connected with the pressure detection unit and the load adjusting unit and is configured to determine current actual load according to the working pressure of the lifting cylinder, carry out overload judgment and overall stability assessment according to the current actual load, and drive the load body to move by controlling the actuating mechanism to change the gravity center position of the overall forklift when the instability risk is judged and the overload degree does not exceed a hard safety threshold value, so that the overall stability of the forklift is compensated, change of the overall stability is monitored in real time, and displacement of the load body is adjusted in a closed loop according to the change until the overall stability is restored to a safety range. The technical problems of complex detection, hysteresis compensation and rough control in the prior art are solved.

Inventors

WU MENG
BI SHENG
ZHANG HONGKAI
ZHANG YUANYI
ZHANG YANJUN
YANG SHUQIANG

Assignees

安徽合力股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260320

Claims (9)

1. An adaptive low-margin forklift overload control system, comprising: the pressure detection unit is used for detecting the working pressure of the lifting oil cylinder of the forklift in real time; the load adjusting unit comprises a movable load body and an actuating mechanism for driving the load body to move; a control unit connected to the pressure detection unit and the load adjustment unit, respectively, and configured to: (a) Determining the current actual load according to the working pressure of the lifting oil cylinder; (b) Carrying out overload judgment and whole vehicle stability assessment according to the current actual load; (c) When the instability risk is judged and the overload degree does not exceed the hard safety threshold, the actuating mechanism is controlled to drive the load body to move so as to change the gravity center position of the whole vehicle, so that the whole vehicle is subjected to self-adaptive stability compensation; (d) And monitoring the change of the stability of the whole vehicle in real time, and adjusting the displacement of the load body in a closed loop mode according to the change until the stability of the whole vehicle is restored to a safe range.
2. The adaptive low-margin forklift overload control system of claim 1, wherein the control unit is specifically configured to: calculating the current actual load And rated load Ratio of (2) When (when) Starting stability evaluation when the monitoring range is within a preset monitoring range; The stability evaluation comprises calculating a stability coefficient in the current state, wherein the stability coefficient is the ratio of the anti-overturning moment to the overturning moment.
3. The adaptive low-margin forklift overload control system of claim 2, wherein the preset monitoring range is 1.0< ≤1.45。
4. The adaptive low-margin forklift overload control system of claim 2, wherein the stability coefficient satisfies a calculation formula: In the formula, Which is indicative of the stability factor in question, Representing the current actual load in question, The weight of the forklift is represented, Indicating the weight of the load body in question, Represents the horizontal distance from the center of gravity of the vehicle body to the front axle, Representing the horizontal distance of the centre of gravity of the load body to the front axle, Representing the horizontal distance of the load center of gravity from the front axle.
5. The adaptive low-margin forklift overload control system of claim 4, wherein the control unit is further configured to: Introducing dynamic load coefficients according to road conditions and/or degree of cargo sway To the stability coefficient Correcting to obtain dynamic stability coefficient And combining the dynamic stability coefficients And preset safety threshold A comparison is made.
6. The adaptive low-margin forklift overload control system of claim 1, wherein: The load body has a preset moving range, and the actuating mechanism drives the load body to move between a starting point and a limiting point; the load adjusting unit further comprises a position detecting module for detecting the actual position of the load body in the moving range in real time and feeding back a position signal to the control unit.
7. The adaptive low-margin forklift overload control system of claim 1, wherein the control unit is further configured to: when the instability risk is judged to exist and the overload degree exceeds the hard safety threshold, the safety locking state is directly triggered, lifting and/or forward tilting actions are forbidden to be executed, and overload early warning is sent out.
8. The adaptive low-margin forklift overload control system of claim 7, wherein the hard safety threshold is 1.3 times the rated load.
9. An overload control method of an adaptive low-margin forklift, applied to the system as claimed in any one of claims 1 to 8, comprising: S1, detecting working pressure of a lifting oil cylinder in real time, and calculating current actual load according to the working pressure; S2, carrying out overload judgment and stability evaluation according to the current actual load; S3, when the instability risk is judged and the overload degree does not exceed the hard safety threshold, the gravity center position of the whole vehicle is changed by driving the load body to move so as to perform self-adaptive stability compensation, the change of the stability of the whole vehicle is monitored in real time, and the displacement of the load body is regulated in a closed loop mode according to the change until the stability of the whole vehicle is restored to the safety range; and S4, triggering a safety locking state when the overload degree exceeds a hard safety threshold, and prohibiting the lifting and/or forward tilting actions.

Description

Self-adaptive low-margin forklift overload control system and method Technical Field The invention relates to the technical field of forklifts, in particular to an overload control system and method for a self-adaptive low-margin forklift. Background At present, the overload protection of the forklift mainly depends on the following two modes: The first is passive protection based on static structural design margin. Namely, a certain safety margin is reserved by means of reinforcing the strength of the structural member, increasing the counterweight and the like, and slight overload is allowed. However, the margin is a fixed value set based on an ideal working condition, and real-time changes such as load center offset, road surface inclination, cargo shaking and the like in actual operation cannot be dynamically perceived. When the adverse working conditions are overlapped, the actual stable allowance of the whole vehicle is compressed sharply, instantaneous overturning is easy to occur, and great potential safety hazards exist. The second is hydraulic system overflow protection. And by arranging an overflow valve in the lifting oil way, overflow is performed when the system pressure exceeds a set threshold value, and continuous lifting is limited. The method can only passively respond after overload occurs, belongs to post protection, cannot distinguish load properties, and is easy to cause false triggering or protection failure. In view of the above problems, intelligent protection technologies capable of dynamically sensing loads and actively adjusting stability have been developed in recent years. For example, chinese patent application publication No. CN109704249a discloses a device and method for protecting an overload of a forklift truck, in which, in the scheme, pressure sensors are installed at four corners of a fork to detect weight distribution of the cargo, angle sensors and displacement sensors are combined to obtain a gantry inclination angle and lifting height, and a gravity center position of the cargo is calculated, and then the gravity center of the whole truck is synthesized with the gravity center of the forklift truck itself and compared with a preset stable region, and when it is determined that the synthesized gravity center exceeds the stable region, the gravity center of the whole truck is changed by adjusting the position of a truck tail counterweight or replacing the counterweight, so that the whole truck is stabilized. The technology realizes the spanning from static protection to dynamic sensing and active adjustment, and improves the active safety level of the forklift. However, the above technical solution still has the following drawbacks in practical application: 1. The detection system is complex and high in cost, the pressure sensors are required to be installed at four corners of the fork respectively, the angle sensors and the displacement sensors are additionally arranged, the number of the sensors is large, the data fusion algorithm is complex, the system cost is high, the calibration is difficult, the sensors are positioned at the positions of the fork which are easy to be impacted, and the reliability is challenged. 2. The compensation mechanism has the advantages of lag response and heavy structure, namely the gravity center of the whole truck is changed by moving the truck tail counterweight, the instantaneous working condition change such as sudden shaking of the cargo is difficult to deal with due to large counterweight mass, large moving inertia and slow response speed, meanwhile, the counterweight adjusting mechanism has large occupied space and complex structure, and the difficulty and the cost for carrying out post-loading reconstruction on the existing forklift platform are high. 3. The control strategy is single, and the refinement and grading are lacking, namely, whether the synthesized gravity center is in a stable area is only used as a unique criterion, the adjustment is triggered once the synthesized gravity center is exceeded, the differential processing logic is not set for the overload degree, and the physical limit of the compensation mechanism is not considered. This may result in over-regulation at slight overload or under-regulation near the limit, failing to balance safety and efficiency. Therefore, how to simplify the detection structure, reduce the cost, improve the rapidness of compensation response and the refinement degree of control strategy, realize the self-adaptive stable compensation for slight overload working conditions, and establish a perfect hard safety locking mechanism becomes a technical problem to be solved in the field. Disclosure of Invention The invention aims to solve the technical problems of how to realize the cooperative optimization of the response speed, the control precision and the structural simplification of the stability compensation under the overload working condition of the forklift through simpler cylinder