Suspension arm deflection compensation method and system based on diagonal angle detection

Abstract

The invention relates to the technical field of lazy arm deflection compensation, and particularly discloses a lazy arm deflection compensation method and system based on diagonal angle detection, and the method comprises the following steps: S1, recording the initial length of a sliding oil cylinder during hoisting, detecting the diagonal angle of a steel wire rope row and the length of a lifting oil cylinder in real time, and obtaining the length of a rocker arm; calculating the horizontal relative displacement of the lifting appliance and the lifted object through the geometric model; s2, the target length of the sliding oil cylinder is set according to the initial length and the horizontal relative displacement, the actual length is detected in real time, the deviation is calculated, and a sliding valve is controlled through PID to compensate the horizontal displacement; the rolling angle deviation of the lifting appliance is synchronously detected, and a leveling valve is driven to realize attitude correction; s3, a sliding displacement threshold value is set, if the compensation amount exceeds the limit, the action is suspended, and mechanical overload or collision is prevented; according to the method, real-time detection of the cable-stayed angle replaces a traditional pre-calibration curve, double-closed-loop control is combined, high-precision self-adaptive compensation is achieved, and efficiency and safety are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of jib deflection compensation, and particularly relates to a jib deflection compensation method and system based on cable angle detection. BACKGROUND

[0002] In various engineering operations and logistics loading and unloading scenarios, the transfer vehicle often undertakes the important task of lifting heavy objects. When the transfer vehicle is lifting, the jib, as a key load-bearing component, will inevitably be deformed due to the weight of the lifted object, specifically manifested as the jib bending downward.

[0003] The influence brought by this deflection deformation is multifaceted. First, in the horizontal direction, there will be a significant misalignment between the sling and the lifted object. Due to the bending deformation of the jib, the relative position between the sling and the lifted object, which was originally in a vertical state, changes, so that the sling cannot be accurately positioned directly above the lifted object. This not only affects the accuracy of lifting, but also may cause the lifted object to sway during lifting, increasing the safety risk. Second, the sling itself will also produce a roll angle tilt. The deformation of the jib will change the force distribution on the sling, causing the sling to have an abnormal spatial posture. This roll angle tilt will further affect the stability and safety of lifting, making it difficult for the sling to maintain balance during lifting, increasing the possibility of the sling falling off or the lifted object losing control.

[0004] In the traditional response method, in order to accurately grasp the deflection deformation of the jib as much as possible, it is necessary to measure 4 deflection curves under different arm lengths and amplitude angles. In actual operation, this means that the staff needs to measure and record multiple times for each combination of arm length and amplitude angle. Since the range of arm length and amplitude angle is large, and the measurement process needs to strictly follow the operating procedures to ensure the accuracy of the data, the entire measurement work not only has a huge workload, but also is very inefficient. SUMMARY

[0005] The purpose of the present application is to provide a jib deflection compensation method and system based on cable angle detection, which solves the following technical problems.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The jib deflection compensation method based on cable angle detection comprises the following steps:

[0008] Step S1: When the sling is carrying the lifted object, record the initial length of the sliding cylinder, real-time acquire the inclination angle of the wire rope row, denoted as the swing arm rotation angle, and acquire the lifting cylinder length and the swing arm length; establish a geometric model, and according to the initial length, the swing arm rotation angle, the lifting cylinder length and the swing arm length, obtain the horizontal relative displacement amount of the sling and the lifted object;

[0009] Step S2: obtaining the target length of the sliding cylinder according to the initial length and the horizontal relative displacement amount; obtaining the actual length of the sliding cylinder in real time, obtaining the amplitude deviation, and driving the sliding valve to perform amplitude direction compensation according to the deviation; obtaining the rolling angle of the lifting tool in real time, obtaining the rolling angle deviation, and driving the leveling valve to perform rolling angle compensation according to the rolling angle deviation;

[0010] Step S3: setting a sliding displacement threshold value, and performing anti-overshoot safety judgment according to the sliding displacement threshold value.

[0011] As a further scheme of the present application: the obtaining process of the horizontal relative displacement amount comprises:

[0012] A geometric model is established, the center of the rotating shaft is recorded as point O, the length of the rocker arm is recorded as OB, the rotating angle of the rocker arm is recorded as ∠BOC, and an isosceles triangle △OBC is obtained, so that OB=OC; the position of the top pulley of the lifting cylinder is recorded as point A, the length of the steel wire rope row between the rotating shaft center and the top pulley of the lifting cylinder is obtained and recorded as OA; in the geometric model, point C and point A are connected, and when the steel wire rope row is subjected to a diagonal tension, a triangle △AOC is obtained;

[0013] According to the geometric model, it is obtained that Where ∠AOC=(180°-∠BOC), and the diagonal tension angle of the steel wire rope row is obtained as And point A and point B are connected, and the horizontal relative displacement amount BD=AB*tan ∠A=(OA+OC)*tan ∠A of the lifting tool and the lifted object is obtained.

[0014] As a further scheme of the present application: the obtaining process of the amplitude deviation comprises:

[0015] The target length L_aim of the sliding cylinder is L_init+ΔL, where L_init is the initial length of the sliding cylinder, and ΔL=BD; according to the target length, the amplitude deviation L_error=L_aim-L_real is obtained, where L_real is the actual length of the sliding cylinder.

[0016] As a further scheme of the present application: the rolling angle deviation A_error=-A_real, where A_real is the rolling angle of the lifting tool.

[0017] As a further scheme of the present application: the process of performing anti-overshoot safety judgment according to the sliding displacement threshold value comprises: if |ΔL| is greater than the sliding displacement threshold value, the compensation is paused.

[0018] The boom amplitude compensation system based on diagonal tension angle detection comprises:

[0019] The input unit comprises a detection module and an operation handle for operating signal input, and the detection module comprises a cable angle encoder, a lifting length sensor, a sliding length sensor and an inclination sensor;

[0020] The lifting length sensor is used for acquiring the length of the lifting cylinder, the cable angle encoder is used for acquiring the inclination angle of the cable row, the sliding length sensor is used for acquiring the sliding stroke, and the sliding stroke is the physical displacement amount when the sliding cylinder is extended or retracted, and the inclination sensor is used for acquiring the rolling angle of the lifting appliance;

[0021] The controller records the initial length of the sliding cylinder, acquires the inclination angle of the cable row in real time, records the swing arm rotation angle, and acquires the length of the lifting cylinder and the length of the swing arm; a geometric model is established, and the horizontal relative displacement amount of the lifting appliance and the hoisted object is obtained according to the initial length, the swing arm rotation angle, the length of the lifting cylinder and the length of the swing arm;

[0022] According to the initial length and the horizontal relative displacement amount, the target length of the sliding cylinder is obtained; the actual length of the sliding cylinder is acquired in real time, and the amplitude deviation is obtained; the rolling angle of the lifting appliance is acquired in real time, and the rolling angle deviation is obtained;

[0023] The output unit comprises a lifting appliance lifting cylinder valve group, a sliding valve and a leveling valve, the lifting appliance lifting cylinder valve group comprises a lifting cylinder, the sliding valve performs amplitude direction compensation according to the deviation, and the leveling valve performs rolling angle compensation according to the rolling angle deviation.

[0024] The beneficial effects of the present application are as follows:

[0025] The present application directly converts the offset amount (millimeter level precision) of the lifting appliance and the hoisted object through cable angle detection, dynamically compensates the sliding cylinder, avoids the cumulative error of the traditional experience curve, realizes the rapid leveling of the lifting appliance posture by combining the inclination sensor with PID control, and is more suitable for complex working conditions of different arm lengths and amplitude angles based on the mathematical calculation of the triangular relationship than the traditional table lookup method; the traditional method needs to measure the perturbation curve for four arm length / amplitude combinations, while the present application directly calculates the compensation amount through real-time detection of the cable angle, greatly reducing the calibration time; and the sliding and leveling cylinders are controlled in the hoisting process without manual intervention, and the single hoisting cycle is greatly shortened.

[0026] In addition, the present application sets a threshold protection, suspends compensation when the sliding displacement exceeds the limit, avoids damage to the mechanical structure due to overload, limits the lateral force of the lifting cylinder through cable angle feedback to prevent abnormal wear of the cable row, and ensures that the compensation algorithm exits in time after the hoisted object leaves the ground or the hoisting is completed to prevent misoperation. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] Figure 1 1 is a flow chart of a boom disturbance compensation method based on oblique pull angle detection according to the present invention;

[0029] Figure 2 Schematic diagram of a boom disturbance compensation system based on oblique pull angle detection according to the present invention;

[0030] Figure 3 It is a structural schematic diagram of a slant angle detection device in a boom disturbance compensation system based on slant angle detection according to the present invention;

[0031] Figure 4 It is a schematic diagram of a simplified mathematical model of the inclined angle detection device in the boom disturbance compensation system based on inclined angle detection of the present invention;

[0032] Figure 5 The present invention is a flowchart of a boom disturbance compensation system based on oblique angle detection. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In existing technology, the crane arm of a transfer truck is rigidly connected to the spreader through a hinge point and a leveling cylinder. The spreader's rotary lock is locked with the load's corner fittings to achieve a rigid connection between the spreader and the load. This rigid connection facilitates the spreader's own posture adjustment, improves spreader loading efficiency, and is the prerequisite for unmanned and fully automated operation of transfer trucks.

[0035] After the spreader is rigidly connected to the load, the transfer truck starts lifting. When the load weighing tens of tons is gradually carried by the boom, the weight of the load causes the boom to bend downward (disturbance), resulting in a misalignment between the spreader and the load in the amplitude direction; at the same time, the spreader itself generates a roll angle.

[0036] The relationship between boom load and its disturbance is closely related to boom length and boom luffing angle. For transfer trucks, there are two different boom lengths and two different luffing angles for different operating scenarios. This requires measuring four boom load and disturbance curves, a significant workload, especially during mass production of transfer trucks.

[0037] See also Figure 2As shown, the present application provides a kind of based on cable angle detection's boom disturbance compensation method and system.The system includes: input unit, controller and output unit.Input unit is by detection module and operating handle, detection module includes cable angle encoder, lifting length sensor, sliding length sensor, inclination sensor;Output unit includes sling lifting valve group, sling sliding valve and sling leveling valve;Controller is responsible for program logic and its algorithm processing.Manipulation handle, sling lifting cylinder extends, boom slowly carries the weight of load;Boom disturbance deformation makes that sling and load produce relative displacement in horizontal direction, simultaneously make the cable on lifting cylinder row produce cable angle, conversion obtains the change of loading vehicle amplitude direction, sliding cylinder executes corresponding displacement, realizes amplitude direction compensation;Real-time detection sling roll angle angle change is simultaneously realized through leveling, and the compensation of sling roll angle is realized.

[0038] The transfer vehicle is mainly composed of a rotary table, a vertical lifting arm, a boom and a sling. After the locking pin on the rotary lock frame is locked with the corner piece of the load, the sling is rigidly connected with the load. One end of the cable row is connected with the rotary lock frame through a pin shaft, and the other end is fixed on the sling by passing through a pulley above the lifting cylinder. The lifting cylinder is extended or retracted to drive the cable row to rise or fall, thereby realizing the vertical movement of the load. The lifting length sensor detects the length of the lifting cylinder. When the boom carries the weight of the load to produce disturbance, the cable angle detection device detects the cable angle. The sliding cylinder realizes the horizontal movement (the amplitude direction of the transfer vehicle) of the sling. The sliding length sensor is used to detect the sliding stroke. The leveling cylinder realizes the adjustment of the roll angle of the sling. The inclination sensor is used to detect the roll angle of the sling.

[0039] The structure diagram of the cable angle detection device is as shown in Figure 3 The cable angle detection device includes two rotating shafts 110, which are respectively installed on both sides of the sling in the cable row 200. The two rotating shafts 110 are each provided with a rocker arm 120. The rocker arms 120 are crossed with an abutting rod 130. The two rotating shafts 110 are each provided with a torsional spring 140, which can drive the rotating shaft 110 to rotate to make the abutting rod 130 always abut with the cable row 200. One of the rotating shafts 110 is provided with a cable angle encoder 160 through a shaft coupling 150. The cable angle encoder 160 can monitor the rotation angle of the rocker arm 120 in real time, and further calculate the cable angle of the cable row 200 and the relative displacement of the sling and the load in the horizontal direction.

[0040] The cable angle detection device is simplified as a mathematical model as shown in Figure 4As shown. O point is the center of the rotating shaft, OB is the length of the rocker arm, ∠BOC is the rotating angle detected by the encoder, OA is the length of the steel wire rope row from the rotating shaft center to the top pulley of the lifting cylinder, ∠A is the angle of the steel wire rope row, and BD is the relative displacement between the lifting appliance and the hoisted object. OB=OC, ∠AOC=(180°-∠BOC), the length of OB is known, the angle of ∠BOC and the length of OA can be measured, and then the following is obtained:

[0041]

[0042] BD=AB*tan∠A=(OA+OC)*tan∠A;

[0043] The operation handle is controlled, the controller processes the handle signal at a constant speed, and then the handle signal is given to the lifting cylinder valve group. The lifting cylinder extends to drive the rope row and the rotating lock frame to rise, and the hoisting of the hoisted object is started. At the same time, the current sliding cylinder length L_init is recorded. The lifting length and the rotating angle signal of the angle of inclination encoder are detected in real time, and the relative displacement between the lifting appliance and the hoisted object in the horizontal direction is calculated. The relative displacement value is set as the displacement increment ΔL of the sliding cylinder, and the target length L_aim of the sliding cylinder is obtained in combination with the initial length L_init of the sliding cylinder, that is, L_aim=L_init+ΔL. The deviation L_error between the actual length L_real of the sliding cylinder and the target length L_aim is calculated, that is, L_error=L_aim-L_real. The sliding valve is controlled by PID to realize the compensation control of the amplitude and the direction of the lifting arm disturbance. At the same time, the inclination signal A_real of the lifting appliance is detected in real time, the deviation A_error between the actual inclination and 0° is calculated, that is, A_error=-A_real, and the leveling valve is controlled by PID to realize the compensation of the direction of the rolling angle of the lifting appliance.

[0044] In addition, the sliding displacement threshold value judgment is increased to prevent the amplitude compensation from overshooting; the pin shaft force threshold value judgment is increased to exit the disturbance compensation algorithm; and the lifting cylinder stroke threshold value is set to also exit the disturbance compensation algorithm, thereby enhancing the robustness of the algorithm. The program flow block diagram is as shown in Figure 5 .

[0045] It can be understood that the present application can compensate for the deviation of the hoisting disturbance of the rotating vehicle in the amplitude direction and the rolling angle direction of the lifting appliance, effectively control the hoisted object to be away from the collision of the box body, and the lateral force of the lifting cylinder is less than the safety threshold value. The lifting cylinder is mainly operated, and the sliding and leveling are controlled, thereby reducing the operation strength.

[0046] It is worth noting that the angle sensor can be used instead of the angle of inclination encoder in the present application, and the passive leveling (self-weight leveling) mode can be used instead of the leveling of the lifting appliance.

[0047] The above has been described in detail one embodiment of the present application, but the content is only the preferred embodiment of the present application, cannot be considered for limiting the scope of the present application. Any equivalent changes and improvements made in the scope of the present application, should still belong to the scope of the present application.

Claims

1. A boom disturbance compensation method based on oblique pull angle detection is characterized in that: The following steps are involved: Step S1: When the spreader is carrying a load, the initial length of the sliding cylinder is recorded, the inclination angle of the wire rope row is obtained in real time, recorded as the rocker arm rotation angle, and the lifting cylinder length and rocker arm length are obtained; a geometric model is established, and the horizontal relative displacement of the spreader and the load is obtained based on the initial length, rocker arm rotation angle, lifting cylinder length, and rocker arm length; Step S2: Obtaining the target length of the sliding cylinder based on the initial length and the horizontal relative displacement; obtaining the actual length of the sliding cylinder in real time, obtaining the amplitude deviation, and driving the sliding valve to perform amplitude direction compensation based on the deviation; obtaining the roll angle of the spreader in real time, obtaining the roll angle deviation, and driving the leveling valve to perform roll angle compensation based on the roll angle deviation; Step S3: setting a sliding displacement threshold, and performing an anti-overshoot safety judgment based on the sliding displacement threshold.

2. The boom disturbance compensation method based on oblique pull angle detection according to claim 1 is characterized in that: In step S1, the process of obtaining the horizontal relative displacement includes: Establish a geometric model, in which the center of the rotating shaft is recorded as point O, the length of the rocker arm is recorded as OB, the rocker arm rotation angle is recorded as ∠BOC, and an isosceles triangle △OBC is obtained, where OB=OC; the position of the top pulley of the lifting cylinder is recorded as point A, and the length of the wire rope row between the center of the rotating shaft and the top pulley of the lifting cylinder is obtained and recorded as OA; connect point C and point A in the geometric model, and when the wire rope row is obliquely stretched, a triangle △AOC is obtained; According to the geometric model, we can get Where ∠AOC=(180°-∠BOC), then the inclined pulling angle of the wire rope row is obtained And connect point A and point B to obtain the horizontal relative displacement of the sling and the load: BD = AB*tan∠A = (OA+OC)*tan∠A.

3. The boom disturbance compensation method based on oblique pull angle detection according to claim 1, characterized in that: In step S2, the process of obtaining the amplitude deviation includes: The target length of the sliding cylinder L_aim=L_init+ΔL, where L_init is the initial length of the sliding cylinder and ΔL=BD; based on the target length, the amplitude deviation L_error=L_aim-L_real is obtained, where L_real is the actual length of the sliding cylinder.

4. The boom disturbance compensation method based on oblique pull angle detection according to claim 1, characterized in that: In step S2, the roll angle deviation A_error=-A_real, wherein A_real is the roll angle of the spreader.

5. The boom disturbance compensation method based on oblique pull angle detection according to claim 3 is characterized in that: In step S3 , the process of performing overshoot prevention safety judgment according to the sliding displacement threshold includes: if |ΔL| is greater than the sliding displacement threshold, suspending compensation.

6. The boom disturbance compensation system based on oblique pull angle detection is characterized by: include: Input unit: including a detection module, the detection module includes a tilt angle encoder, a lifting length sensor, a sliding length sensor and an inclination sensor; The lifting length sensor is used to obtain the length of the lifting cylinder, the inclined pull angle encoder is used to obtain the inclination angle of the wire rope row, the sliding length sensor is used to obtain the sliding stroke, and the sliding stroke is the physical displacement of the sliding cylinder when it is extended and retracted. The inclination sensor is used to obtain the roll angle of the spreader; The controller records the initial length of the sliding cylinder, obtains the inclination angle of the wire rope in real time, records it as the rocker arm rotation angle, and obtains the lifting cylinder length and rocker arm length. A geometric model is established to obtain the horizontal relative displacement of the spreader and the load based on the initial length, rocker arm rotation angle, lifting cylinder length, and rocker arm length. According to the initial length and the horizontal relative displacement, the target length of the sliding cylinder is obtained; the actual length of the sliding cylinder is obtained in real time to obtain the amplitude deviation; the roll angle of the spreader is obtained in real time to obtain the roll angle deviation; The output unit includes a spreader lifting cylinder valve group, a sliding valve and a leveling valve. The spreader lifting cylinder valve group includes a lifting cylinder. The sliding valve performs amplitude direction compensation according to the deviation. The leveling valve performs roll angle compensation according to the roll angle deviation.

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