An automatic centering method for a bridge crane with self-compensation function

Abstract

The application discloses a kind of self-compensation function's bridge crane automatic centering method, comprising: whether the sling is in the straight state by tension sensor judging sling;If the sling is in the state of not straightening, then control reel rotates to the sling is in the straight state;If the sling is in the straight state, then the real-time rope length of sling is obtained by encoder;According to real-time rope length, calculate centering reference, and the centering reference under different heights is compensated, and the sling oblique pull angle is obtained;According to the sling oblique pull angle, calculate sling offset;According to the sling offset, run the trolley and carry out centering.Such, accurate trolley and hoisting weight relative position offset is obtained by sensor and the centering compensation algorithm designed, then precise automatic centering operation is realized by motion control system based on PLC, accurate automatic centering of bridge crane can be realized quickly in short time, effectively avoid the safety problem caused by skewing and oblique sling.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation, and in particular to an automatic centering method for a bridge crane with self-compensation function. BACKGROUND

[0002] The bridge crane is an important equipment for realizing the mechanization and automation of production process in modern industrial production and hoisting, and is widely used in industrial and mining enterprises, steel and chemical industry, railway transportation, port and wharf, and logistics turnover. The safety of the bridge crane has always been a concern of the users and researchers. Before hoisting, the oblique hoisting of the hoisting rope can cause serious harm. On the one hand, the stress of the hoisting rope increases when hoisting obliquely, which may exceed the load, and even accidents such as the hoisting rope being pulled off may occur. On the other hand, the horizontal component force generated when hoisting obliquely can make the heavy object swing towards the vertical center at the moment when the heavy object leaves the ground or the carrier, and collide with the hanging personnel, surrounding operating personnel or other objects, causing accidents. Therefore, when hoisting, the hoisting rope of the bridge crane should pass through the center of gravity of the hoisted object and remain vertical.

[0003] Oblique hoisting refers to the situation that when the hoisted object is on the ground, the center of gravity of the hoisted object does not coincide with the perpendicular line of the hoisting rope. If the hoisted object is hoisted at this moment, a large initial oblique angle will be generated, which may cause safety accidents. The principle of measuring the oblique angle of the hoisting rope by using the displacement sensor is to fix the pull rope of the displacement sensor on the hoisting rope. When the hoisting rope swings, the pull rope will be stretched or contracted. By measuring the vertical distance from the displacement sensor to the fixing point of the hoisting rope, the oblique angle of the hoisting rope can be calculated.

[0004] At present, the main solution is to adjust the crane repeatedly by the eyes of the operator, which has low adjustment efficiency and low automation degree. Some enterprises have taken measures to prevent the crane from being obliquely pulled. To solve this problem, the current solution is to monitor the oblique angle of the hook and the hoisting center when hoisting. When the oblique angle exceeds a given threshold, an audible and visual alarm is started, and hoisting is stopped. Therefore, accurate measurement of the oblique angle is particularly important. Common methods for measuring the oblique angle include: (1) detecting the oblique angle of the hoisting rope based on an electronic angle sensor; (2) detecting the oblique angle of the hoisting rope based on the encoders in two directions of the trolley and the car; (3) collecting the image of the rope length, analyzing the oblique angle of the hoisting rope, collecting the image of the hook, and calculating the position of the hook center and the angle of deviation from the hoisting center after image processing. SUMMARY

[0005] The embodiment of the present application provides an automatic centering method for a bridge crane with self-compensation function, which can quickly realize accurate automatic centering of the bridge crane in a short time, and effectively avoid the safety problems caused by oblique hoisting.

[0006] To achieve the above-mentioned purpose, the technical scheme of the embodiment of the present application is:

[0007] In a first aspect, the embodiments of the present application provide a bridge crane automatic centering method with self-compensation function, comprising:

[0008] determining whether the hoisting rope is in a straightened state through a tension sensor; if the hoisting rope is not in the straightened state, controlling the drum to rotate until the hoisting rope is in the straightened state;

[0009] if the hoisting rope is in the straightened state, obtaining a real-time rope length of the hoisting rope through an encoder; calculating a centering reference according to the real-time rope length, compensating the centering reference at different heights, and obtaining a hoisting rope oblique pull angle;

[0010] calculating a hoisting rope offset according to the hoisting rope oblique pull angle;

[0011] running a crab according to the hoisting rope offset to center.

[0012] In some possible implementation manners, if the hoisting rope is not in the straightened state, the hoisting rope oblique pull angle measured is greater than a theoretical oblique pull angle, and the real-time rope length is greater than a theoretical rope length, the drum is controlled to rotate until the hoisting rope is in the straightened state.

[0013] In some possible implementation manners, the centering reference is calculated according to the real-time rope length, and the hoisting rope oblique pull angle is obtained by compensating the centering reference at different heights, comprising: determining the hoisting rope oblique pull angle according to the centering reference, and the hoisting rope oblique pull angle is represented by the following formula: q=tan -1 (2H / (W-D)),

[0014] wherein H is a lifting height; W is a distance between two ends of the hoisting rope, the distance is in proportional relationship with the lifting height, that is, W=kH, k is a proportional constant; D is a diameter of a movable pulley; L is a rope length; q is the hoisting rope oblique pull angle; n is a vertical displacement of a displacement sensor to a fixed end of the hoisting rope; and m is a displacement length of the displacement sensor, m=n / tan a.

[0015] In some possible implementation manners, the calculation of the sling offset according to the sling oblique angle includes: A and B are installation positions of the pull wire displacement sensor; O is the intersection of the installation frame; C is the centering position of the sling; D is the position of the sling in the "oblique sling" state; H and W are distances of the pull wire displacement sensors A and B from the coordinate origin, and the values are obtained by measurement; AC and BC are lengths of the pull wire in the centered state, and the values are obtained by calculation; AD and BD are lengths of the pull wire in the "oblique sling" state, and the values are obtained by measurement of the pull wire displacement sensor; w and h are offset amounts in the direction of the crane car and the crane trolley, respectively; w and h are obtained according to the cosine law and are represented as:

[0016]

[0017]

[0018]

[0019] f = e + d - 90°,

[0020] w = BD * sin(f),

[0021] h = AD * sin(b),

[0022] wherein a is an included angle between the line connecting the installation positions of the two pull wire displacement sensors and the direction of the trolley movement, d is an included angle between the line connecting the installation positions of the two pull wire displacement sensors and the direction of the crane car movement, e is an included angle between the line connecting the installation positions of the two pull wire displacement sensors and the pull wire BD, f is the oblique angle in the direction of the crane car, and b is the oblique angle in the direction of the trolley.

[0023] In some possible implementation manners, the operation of the crane car and the crane trolley according to the sling offset to center includes:

[0024] the displacement of the trolley to be corrected x, the speed of the trolley v c , the length of the sling l, and the retraction speed of the sling v l ; if the speed of the trolley movement is to be matched with the retraction speed of the sling during the centering process, x and l need to satisfy: l = x / cosθ,

[0025] the speed of the trolley movement is to be matched with the retraction speed of the sling during the centering process, x and l need to satisfy: l = x / cosθ, l = v x / cosθ, wherein θ is the oblique angle in the direction of the trolley;

[0026] The control strategy of the anti-oblique sling automatic centering is to straighten the sling by the data of the tension sensor, and then correct the position according to the oblique angle as the centering criterion, and the movement speed of the crane car and the crane trolley and the retraction speed of the sling are constrained during the correction process.

[0027] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0028] The automatic centering method of the bridge crane with the self-compensation function provided in the embodiments of the present application judges whether the hoisting rope is in a straight state through the tension sensor; if the hoisting rope is in the straight state, the real-time rope length of the hoisting rope is obtained through the encoder; the centering reference is calculated according to the real-time rope length, and the centering reference under different heights is compensated to obtain the hoisting rope oblique angle; the hoisting rope offset is calculated according to the hoisting rope oblique angle; and the centering is performed by running the trolley according to the hoisting rope offset. In this way, the accurate relative position offset between the trolley and the hoisting weight is obtained through the sensor and the designed centering compensation algorithm, and the accurate automatic centering operation is realized through the motion control system based on the PLC, so that the accurate automatic centering of the bridge crane can be quickly realized in a short time, and the safety problem caused by the oblique hoisting can be effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0030] Figure 1 An embodiment flowchart of the automatic centering method of the bridge crane with the self-compensation function provided in the embodiments of the present application is shown in the figure.

[0031] Figure 2 An illustration of the hoisting rope not being straight in the embodiments of the present application is shown in the figure.

[0032] Figure 3 An illustration of the centering error provided in the embodiments of the present application is shown in the figure.

[0033] Figure 4 An illustration of the hoisting rope included angle provided in the embodiments of the present application is shown in the figure.

[0034] Figure 5 A measurement principle diagram of the tension wire displacement sensor provided in the embodiments of the present application is shown in the figure.

[0035] Figure 6 A principle diagram of the automatic centering speed constraint provided in the embodiments of the present application is shown in the figure.

[0036] Figure 7 An automatic centering sensor installation schematic diagram in the embodiments of the present application is shown in the figure.

[0037] Figure 8 An automatic centering process schematic diagram in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0038] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0039] In the related description of the present embodiment, the terms “include, contain, have” and the like are open terms, which are generally preferred to be understood as including but not limited to; the term “at least one” is generally preferred to be understood as one or more, wherein “more” refers to two or more; the term “at least one of” or the like refers to any combination of the terms, including any combination of single or multiple terms.

[0040] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0041] Those skilled in the art should understand that the numerical ranges in the embodiments of the present application should be understood as also specifically disclosing each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or stated range of values and any other stated value or stated range of values is also included within the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0042] In order to illustrate the technical solutions of the present application, the following will be described through specific embodiments.

[0043] Based on this, the embodiment of the present application provides an automatic centering method of a bridge crane with self-compensation function, which can quickly realize accurate automatic centering of the bridge crane in a short time, and effectively avoid the safety problems caused by skewing the lifting belt.

[0044] Figure 1 An embodiment flowchart of an automatic centering method of a bridge crane with self-compensation function provided by the present application is shown in FIG. 1. Figure 1 The method can include the following steps.

[0045] S101, determining whether the lifting rope is in a straight state by a tension sensor; if the lifting rope is not in the straight state, rotating the winding drum until the lifting rope is in the straight state.

[0046] It should be noted that if the lifting rope is not in the straight state before automatic centering, the measured skewing angle β 测 is greater than β理 , measured rope length l 测 greater than l 理 At this time, directly automatic centering can result in failure to accurately measure the real offset angle of the hoisting rope, so that the centering function cannot be realized, see Figure 2 , Figure 2 is a schematic diagram of the hoisting rope not being straightened in the embodiment of the present application.

[0047] In order to avoid the phenomenon of centering error due to the hoisting rope not being straightened before automatic centering, a method of detecting the tension of the hoisting rope by using a tension sensor and then judging whether the hoisting rope is in a straightened state is proposed. When the hoisting rope is in a straightened state, the tension thereof should be greater than a certain value, and since the value is in a range of variation, a fixed value can be given according to experience. Therefore, before the trolley is positionally corrected, the drum is controlled to rotate until the hoisting rope is in a straightened state.

[0048] S102, if the hoisting rope is in a straightened state, the real-time rope length of the hoisting rope is obtained by using an encoder; a centering reference is calculated according to the real-time rope length, and the centering reference at different heights is compensated to obtain a hoisting rope oblique tension angle.

[0049] The real-time rope length is obtained by using an encoder, and the centering reference is calculated according to the real-time rope length. As shown in Figure 3 , Figure 3 is a centering error schematic diagram provided by the embodiment of the present application. Since the hoisting rope has a fixed end, the hoisting rope included angle is different under different rope lengths, which causes the measured value of the tension wire displacement sensor when the hoisting rope is in a centered state to be different at different heights, which causes the centering reference at different heights to be different, so the centering reference at different heights needs to be compensated.

[0050] As shown in Figure 4 , Figure 4 is a hoisting rope included angle schematic diagram provided by the embodiment of the present application. According to Figure 4 , the angle a can be obtained as:

[0051] q=tan -1 (2H / (W-D)),

[0052] wherein H is the lifting height; W is the distance between the two ends of the hoisting rope, which is in a proportional relationship with the lifting height, that is, W=kH, k is a proportional constant; D is the diameter of the movable pulley; L is the rope length; q is the hoisting rope oblique tension angle; n is the vertical displacement of the tension wire displacement sensor to the fixed end of the hoisting rope; and m is the tension wire length of the tension wire displacement sensor.

[0053] wherein the tension wire length w of the tension wire displacement sensor is represented as:

[0054] m=n / tan a.

[0055] S103, calculate the cable offset according to the cable inclination angle.

[0056] Specifically, as shown in Figure 5 , Figure 5 is a measurement principle diagram of the cable displacement sensor, A and B are the installation positions of the cable displacement sensor; O is the intersection of the installation frame, which is also the origin of the coordinate system; C is the centering position of the cable; and D is the position of the cable in the "inclined and oblique hoisting" state. H and W are the distances of the cable displacement sensors A and B from the coordinate origin, respectively, and the values can be obtained by measurement; AC and BC are the lengths of the cables in the centered state, which are the reference values and can be obtained by calculation; AD and BD are the lengths of the cables in the "inclined and oblique hoisting" state, which can be measured by the cable displacement sensor; w and h are the offsets in the directions of the car and the trolley, respectively; according to the cosine law, w and h can be obtained, i.e.:

[0057]

[0058]

[0059]

[0060] f = e + d - 90°,

[0061] w = BD * sin (f).

[0062] Similarly, it can be determined that:

[0063] h = AD * sin (b).

[0064] Wherein, a is the angle between the line connecting the installation positions of the two cable displacement sensors and the direction of the trolley movement, d is the angle between the line connecting the installation positions of the two cable displacement sensors and the direction of the trolley movement, e is the angle between the line connecting the installation positions of the two cable displacement sensors and the cable BD, f is the oblique angle of the trolley direction, and b is the oblique angle of the car direction.

[0065] S104, run the trolley and the car according to the cable offset to center.

[0066] According to the offset of the trolley and the car obtained in the last step, the offset is reduced by running the trolley and the car. In the automatic centering process, the trolley movement and the cable contraction are required to be performed at the same time, so the speed of the trolley and the contraction speed of the cable need to be constrained to avoid the phenomenon that the hoisting weight is lifted to be out of the ground and swings during the centering process due to too fast contraction of the cable, or the offset measurement error becomes larger due to too slow contraction of the cable, which affects the centering effect. In the process of contracting the cable, the centering reference is constantly adjusted according to the change of the rope length.

[0067] Referring to Figure 6 as shown, Figure 6The automatic centering speed constraint schematic diagram provided by the embodiment of the present application, the trolley to be corrected displacement x, the trolley speed v x , the length of the hoisting rope l, the hoisting rope contraction speed v l . If the trolley moving speed is matched with the hoisting rope recovery speed during the centering process, x and l need to satisfy: l=x / cosθ, wherein θ is the inclined angle of the trolley direction;

[0068] The above formula is differentiated with respect to time t on both sides to obtain: v l =v x / cosθ.

[0069] The control strategy of the automatic centering of the inclined and oblique hoisting is that the hoisting rope is first stretched straight through the data of the tension sensor, and then the position is corrected by taking the inclined angle as the centering criterion, and the moving speed of the large and small trolleys and the rope recovery speed are constrained during the correction process.

[0070] The automatic centering method of the bridge crane with self-compensation function provided by the present application detects the hoisting rope tension by using a tension sensor to further judge whether the hoisting rope is in a straight state, controls the rotation of the drum to make the hoisting rope in a straight state when the hoisting rope is not in a straight state, obtains the real-time rope length through an encoder, calculates the centering reference according to the rope length, and compensates the centering reference at different heights; the hoisting rope offset is measured through a tension displacement sensor; the large and small trolleys are operated according to the measured offset to center. In this way, the relative position offset between the trolley and the hoisting weight is obtained through the sensors and the designed centering compensation algorithm, and the precise automatic centering operation is realized through the motion control system based on PLC.

[0071] Figure 7 The automatic centering sensor installation schematic diagram in the embodiment of the present application, Figure 8 The automatic centering process schematic diagram in the embodiment of the present application. Through the precise automatic centering method of the bridge crane with self-compensation function provided by the present application, the precise automatic centering of the bridge crane can be quickly realized in a short time, and the safety problem caused by the inclined and oblique hoisting can be effectively avoided.

[0072] In some embodiments, the above centering method can also be tested by the following process:

[0073] 1) Test the trolley alignment. The premise is to keep the trolley and load in the center, that is, the trolley and load are in the same plane and perpendicular to the ground, and the angle of deviation is 0. At this time, change the initial position of the trolley to make it skew with the load, press the "automatic centering" button of the control handle to start the automatic centering program. The experiment selects four different deviations before centering and corresponding angles of deviation, measures and records the deviations of the trolley and the corresponding angles of deviation after the automatic centering and manual centering experiments, and the time for completing the centering process. Then process the recorded data to find out the improvement of the automatic centering compared with the manual centering in the centering accuracy and efficiency. If the improvement effect exceeds 40%, it is qualified, otherwise it is unqualified.

[0074] 2) Test the trolley alignment. The premise is to keep the trolley and load in the center, that is, the trolley and load are in the same plane and perpendicular to the ground, and the angle of deviation is 0. At this time, change the initial position of the trolley to make it skew with the load, press the "automatic centering" button of the control handle to start the automatic centering program. The experiment selects four different deviations before centering and corresponding angles of deviation, measures and records the deviations of the trolley and the corresponding angles of deviation after the automatic centering and manual centering experiments, and the time for completing the centering process. Then process the recorded data to find out the improvement of the automatic centering compared with the manual centering in the centering accuracy and efficiency. If the improvement effect exceeds 40%, it is qualified, otherwise it is unqualified;

[0075] 3) Test the trolley alignment. Change the initial position of the trolley to make it skew with the load, press the "automatic centering" button of the control handle to start the automatic centering program. The experiment selects four different deviations before centering and corresponding angles of deviation, measures and records the deviations of the trolley and the corresponding angles of deviation after the automatic centering and manual centering experiments, and the time for completing the centering process. Then process the recorded data to find out the improvement of the automatic centering compared with the manual centering in the centering accuracy and efficiency. If the improvement effect exceeds 40%, it is qualified, otherwise it is unqualified;

[0076] The test results in the above test process are shown in Tables 1 to 6 as follows:

[0077] Table 1 is the trolley direction alignment test

[0078]

[0079] Among them, east and north are defined as positive directions (+), and west and south are defined as negative directions (-);

[0080] Table 2 is the trolley direction alignment test data processing

[0081]

[0082] The calculation method of the index improvement effect in the definition table is (manual centering result-automatic centering result) / manual centering result, which indicates that the automatic centering improves the accuracy and efficiency by a percentage compared with the manual centering.

[0083] Table 3 is a large car direction centering test

[0084]

[0085] Table 4 is large car direction centering test data processing

[0086] Parameter Index Manual alignment Automatic alignment Index improvement effect (%) Average value of deflection angle after alignment 0.292° 0.114° 60.96 Average value of deflection after alignment 3.125 cm 1.225 cm 60.80 Average value of alignment time 33.56s 13.698s 59.18

[0087] Table 5 is a large and small car direction centering test

[0088]

[0089] Table 6 is large and small car direction centering test data processing

[0090]

[0091]

[0092] The automatic centering method of the bridge crane with self-compensation function provided by the application judges whether the hoisting rope is in a straight state through a tension sensor; if the hoisting rope is in a straight state, the real-time rope length of the hoisting rope is obtained through an encoder; the centering reference is calculated according to the real-time rope length, and the centering reference at different heights is compensated to obtain the hoisting rope oblique pull angle; the hoisting rope offset is calculated according to the hoisting rope oblique pull angle; and the large and small cars are operated according to the hoisting rope offset to center. In this way, the accurate trolley and hoisting weight relative position offset is obtained through the sensor and the designed centering compensation algorithm, and the accurate automatic centering operation is realized through the motion control system based on the PLC, so that the accurate automatic centering of the bridge crane can be quickly realized in a short time, and the safety problem caused by the oblique pull and hoisting is effectively avoided.

[0093] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the difference from other embodiments.

[0094] The above examples are only used to illustrate the technical solutions of the application, and are not limited to the application; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the application.

Claims

1. A method for automatic centering of a bridge crane with self-compensation, characterized in that, The method comprises: determining whether the hoisting rope is in a straightened state through a tension sensor; if the hoisting rope is not in the straightened state, controlling the rotation of the winding drum until the hoisting rope is in the straightened state; if the hoisting rope is in the straightened state, obtaining the real-time rope length of the hoisting rope through an encoder; calculating a centering reference according to the real-time rope length, compensating the centering reference at different heights, and obtaining a hoisting rope oblique pulling angle; calculating a hoisting rope offset according to the hoisting rope oblique pulling angle; operating the size car according to the hoisting rope offset to center; the calculation of the centering reference according to the real-time rope length and the compensation of the centering reference at different heights to obtain the hoisting rope oblique pulling angle comprises: determining the hoisting rope oblique pulling angle according to the centering reference, which is expressed by the following formula: ， Wherein, H is the lifting height; W is the distance between the two ends of the hoisting rope, which is in proportional relationship with the lifting height, that is , k is the proportional constant; D is the diameter of the movable pulley; q is the angle of the hoisting rope; L is the length of the rope; n is the vertical displacement of the displacement sensor to the fixed end of the hoisting rope; m is the length of the displacement sensor, ; the calculation of the hoisting rope offset according to the hoisting rope oblique pulling angle comprises: A and B are the installation positions of the pulling displacement sensors; O is the intersection of the mounting frame; C is the centering position of the hoisting rope; D is the position of the hoisting rope in the "oblique pulling and oblique hoisting" state; H and W are the distances of the pulling displacement sensors A and B from the coordinate origin, which are obtained by measurement; AC and BC are the lengths of the pulling lines in the centering state, which are obtained by calculation; AD and BD are the lengths of the pulling lines in the "oblique pulling and oblique hoisting" state, which are obtained by measurement of the pulling displacement sensors; w and h are the offsets in the directions of the size car and the large car respectively; w and h are obtained according to the cosine law and are expressed as: ， ， ， ， ， ， wherein a is the included angle between the connecting line of the two pulling displacement sensor installation positions and the direction of the car movement, d is the included angle between the connecting line of the two pulling displacement sensor installation positions and the direction of the large car movement, e is the included angle between the connecting line of the two pulling displacement sensor installation positions and the pulling line BD, f is the oblique pulling angle in the direction of the large car, and b is the oblique pulling angle in the direction of the size car.

2. The method of claim 1, wherein, if the hoisting rope is not in the straightened state, controlling the rotation of the winding drum until the hoisting rope is in the straightened state, comprises: if the hoisting rope is not in the straightened state, the measured hoisting rope oblique pulling angle is greater than the theoretical oblique pulling angle, and the real-time rope length is greater than the theoretical rope length, then the winding drum is controlled to rotate until the hoisting rope is in the straightened state.

3. The method of claim 1, wherein, operating the size car according to the hoisting rope offset to center, comprises: trolley displacement to be corrected trolley speed sling length sling retraction speed if the trolley movement speed during the centering process is to be matched with the sling retraction speed, then and the following must be satisfied: , Simultaneously divide both sides of the above equation by time The differential is: where, is the cable angle in the trolley direction. the control strategy of the anti-oblique pulling and oblique hoisting automatic centering is to pre-straighten the hoisting rope through the data of the tension sensor, and then to correct the position according to the oblique pulling angle as the centering criterion, and to constrain the moving speed of the size car and the rope winding speed during the correction process.

Images