State estimation and control method for automobile crane under light-load working condition

Abstract

The invention discloses a state estimation and control method for an automobile crane under a light-load working condition. The number of the crane supporting legs can be four or more. In the initial state, the supporting leg system is unfolded according to needs, and geometric and load coupling initial leveling is carried out, namely loading operation is carried out; the method comprises the following steps: firstly, measuring and constructing a state estimation matrix, and estimating a chassis inclination angle and a supporting leg load generated by loading operation corresponding to a next time node based on a driver instruction and a state estimation equation; and then light-load working condition judgment and compensation requirement judgment are sequentially carried out, after the conditions are met, the landing leg compensation amount is calculated based on a front feedback composite and attitude-load coupling global control equation, and then synchronous control over loading operation and landing leg compensation is carried out. According to the method, for a crane with any leg number / leg type, under the light-load working condition that no zero-load suspension occurs on each leg in loading operation, the future state is accurately estimated, full-target optimization landing leg compensation is implemented, a chassis is kept approaching to be horizontal in real time, the load approaching theory of each leg is optimal, and the operation efficiency and stability are improved.

Description

Technical Field

[0001] This invention belongs to the field of truck cranes, specifically relating to the control of truck crane outrigger systems. Background Technology

[0002] In the operation of truck cranes, concrete pump trucks, and similar equipment, the outrigger system provides baseline support. According to the standard "Safety Technical Regulations for the Use of Construction Machinery JGJ33-2012," "Before operation, all outriggers should be fully extended, ensuring that the inclination of the slewing support surface is no greater than 1 / 1000 when unloaded." The "Safety Operating Procedures for Truck Cranes DL / T5250-2010" states, "Adjust the outriggers to make the crane level, ensuring its inclination meets the specifications in the equipment's technical documents, and that the tires are off the ground." Although the chassis is adjusted to be level and the outriggers effectively bear load before operation, the geometric posture and leg load distribution are often disrupted during upper-level operations, leading to frequent reports of overturning accidents due to instability. Currently, due to industry standards and technical barriers, active control of the outriggers during operation is not yet supported. Specifically, the "Safety Technical Regulations for the Use of Construction Machinery JGJ33-2012" states, "The outrigger control valves must not be operated during operation. Adjustments to the outriggers should be made when unloaded." The "Safety Operation Procedures for Truck Cranes DL / T5250-2010" stipulates that "the outrigger control handles must not be operated during operation."

[0003] Our team has successively developed a leveling control method for a multi-point support platform (ZL202110075160.2 / US12097737B2), which can accurately and quickly achieve geometric leveling and leg load control. We have also developed an automatic control method for maintaining the attitude of the truck crane chassis during upper structure operations (ZL202110742181.5), which achieves real-time stability of the crane's geometric attitude during operation based on a feedforward approach. Finally, we have developed a stability control method for the outrigger system of a truck crane during operation (CN202211559189.9), which maintains the chassis attitude close to geometric level in real-time while simultaneously ensuring that the load distribution of each outrigger approaches the theoretical optimal load, comprehensively improving the safety and operational efficiency of truck cranes and other special vehicles with outrigger systems. These three patents (applications) support each other and constitute a forward-looking attempt at active control of outriggers during truck crane operations, potentially leading to a universal, all-condition autonomous outrigger control system applicable to any number / type of outriggers (hereinafter referred to as Prior Artworks 1-3). However, in-depth simulation and experimental verification revealed several theoretical and technical flaws in the aforementioned innovative technologies, which urgently need improvement. Specifically:

[0004] (1) Comparative documents 2 and 3 use equivalent stiffness under different measurement methods to construct the deformation coordination relationship between each outrigger (i.e., assuming that the top surface of the outrigger is still a plane after deformation), and then introduce mechanical equilibrium equations to achieve static determinate solution of the statically indeterminate problem, and obtain the deformation of each outrigger. This scheme has two problems: ① The above plane assumption does not hold true on the actual crane chassis. Because the outrigger is connected to the chassis through the outrigger boom, the outrigger deformation is affected by the chassis, boom, and outrigger as a whole, and the apex of the outrigger is not coplanar. ② The equivalent stiffness used in the above deformation coordination relationship is difficult to match with the actual project no matter how it is valued, and the traditional deformation coordination relationship construction is difficult to achieve. The above two factors cause the estimated values ​​given by the prediction model of comparative documents 2-3 to deviate from reality, resulting in a fundamental error, and thus poor control.

[0005] (2) The outrigger compensation solution model (Formula 7) given in document 3 only calculates the loads of each outrigger and the two-dimensional tilt angle of the chassis that will be generated at the next time node, and then performs the upturn operation and outrigger compensation action. It does not fully consider the impact of the residual attitude and load error after the previous round of control on the subsequent control, resulting in accumulated error, which needs to be further improved.

[0006] (3) In both actual engineering and theoretical research, a large number of outriggers will be suspended (with zero load) during the operation of the superstructure. On the one hand, the special situation of outrigger suspension cannot be accounted for in the above-mentioned prediction model; on the other hand, outrigger suspension is an important cause and precursor to crane overturning. Therefore, the corresponding situation must be fully considered and dealt with in the control plan. This point was not considered in the preliminary application of our team.

[0007] (4) Evaluation indicators for whether outrigger control is required include chassis tilt angle prediction and outrigger load prediction. Exceeding a threshold indicates the need for control. Preliminary applications use the maximum value of the ratio of the absolute value of the deviation between the current load and the expected load of each outrigger to its expected load. Whether the threshold is exceeded is determined. Since the expected load of a specific outrigger may be a very small value (or even zero or negative), the above evaluation indicators have poor engineering usability.

[0008] Anticipating the enormous application prospects of implementing active control of outrigger systems in crane work areas (green operation, unmanned control, and intelligent equipment), this application overcomes the above shortcomings and constructs a state prediction and control method for light-load truck cranes. This is a necessary means to ultimately build full-cycle active control of outrigger systems with any number / type of outriggers. Summary of the Invention

[0009] In view of the above shortcomings, this invention provides a method for state prediction and control of a lightly loaded truck crane. The crane may have four or more outriggers. In the initial state, the outrigger system is deployed as needed and initial leveling is performed using geometric and load coupling, ready for loading operations. This method first measures and constructs a state prediction matrix, predicting the chassis tilt angle and outrigger loads corresponding to the loading operations at the next time node based on driver commands and state prediction equations. Then, it sequentially performs light-load condition determination and compensation requirement determination. Once the conditions are met, the outrigger compensation amount is calculated based on the forward feedback composite and attitude-load coupled global control equations, thereby implementing synchronous control of loading operations and outrigger compensation. This method is applicable to cranes with any number of outriggers. Under light-load conditions where no outrigger is suspended without zero load during loading operations, it can accurately predict future states and implement full-objective optimization of outrigger compensation, maintaining the chassis close to level in real time and ensuring that the loads of each outrigger approach the theoretical optimum, thus improving operational efficiency and stability.

[0010] This invention discloses a method for state prediction and control of a light-load truck crane. The crane is driven by a luffing cylinder for luffing, a slewing mechanism for slewing, a telescopic mechanism for extending and retracting the boom, and a winch mechanism for raising and lowering the load. The crane has four or more outriggers (n), with the outrigger furthest to the left of the driver designated as outrigger 1, and numbers assigned from 2 to n in a counter-clockwise spiral. Each outrigger is equipped with a force sensor to measure its vertical load and a displacement sensor to measure its vertical displacement. The coordinate system of the method is defined with the geometric center of the slewing mechanism as the origin, the x-axis parallel to the ground and pointing forward to the driver, the y-axis pointing to the driver's left, and the z-axis vertically upward. The longitudinal and transverse coordinates of each outrigger are defined as follows: The slewing mechanism has an attitude sensor fixed at its geometric center to measure the tilt angle of the chassis around the x-axis and y-axis; its characteristic is that, in the initial state, the outrigger system has fully or partially deployed and fixed the outrigger booms as needed, with each outrigger supporting the crane until the tires are completely suspended in the air, the load has been lifted off the ground, and initial leveling has been implemented through geometric horizontal and load equalization coupling, ready to carry out upper-mounted operations such as lifting, luffing, slewing, and winching, including the following operating steps:

[0011] Step 101, State Prediction, specifically includes: applying a force of 1 unit vertically downwards at the geometric center of the slewing mechanism, the unit value conforming to the standard of normalization; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively, using the attitude sensor and force sensor; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the first column of the (n+2)×3 dimensional matrix shown in Formula 1; then, first applying a torque of 1 unit around the x-axis, and then applying a torque of 1 unit around the y-axis, the unit value conforming to the standard of normalization, at the geometric center of the slewing mechanism; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the second and third columns of the (n+2)×3 dimensional matrix, until a state prediction matrix is ​​constructed. ;

[0012] Formula 1;

[0013] The unitization of the vertical force and torque is carried out independently. The standard is that after the corresponding value is applied, the load of more than half of the outriggers increases or decreases by more than 5%, and there is no situation where the outrigger load becomes zero or the outrigger is suspended. This is the basis for evaluation. The measurement of the state prediction matrix can be carried out before leaving the factory, but the extension degree of each outrigger arm should be consistent with the actual working conditions.

[0014] Step 102: Calculate the total weight G and centroid coordinates of the crane at the current moment. ; Detect the lifting, luffing, and slewing commands input by the operator, and control the crane to temporarily suspend the corresponding upper-body operations; Estimate the total weight of the crane after the corresponding upper-body operations at the next time point. and new centroid coordinates The increments of vertical force, torque around the x-axis, and torque around the y-axis are decomposed from the migration data of the new centroid coordinates to construct a load migration column vector. Furthermore, the vertical force and torque in the load migration column vector should be normalized in the same way as above; the order of the load migration column vectors is consistent with the order of the column vectors of the state prediction matrix; if the order of the three columns of the state prediction matrix is ​​changed as a whole, the order of the load migration column vectors needs to be changed accordingly.

[0015] Based on the state prediction matrix and the load migration column vector, a state prediction equation is constructed, Equation 2, to solve for the increase in chassis tilt angle and outrigger load caused by the centroid migration generated by the corresponding superstructure operation.

[0016] Formula 2;

[0017] If the upper-mounted operation does not involve the loading and unloading of the load, the first column of the state prediction matrix and the first row of the load migration column vector can be deleted to construct a simplified state prediction equation, Formula 3;

[0018] Formula 3;

[0019] The increments of the chassis tilt angle and outrigger load are respectively compared with the measured value of the chassis tilt angle at the current moment. and the current measured value of outrigger load Add them together to obtain the estimated chassis tilt angle at the next time point. Outrigger load estimate .

[0020] Step 103, light load condition determination, specifically includes: constructing a crane lifting performance table under the current outrigger boom extension degree, wherein the maximum lifting weight of the lifting performance table must cover the extreme situation where any outrigger has zero load or is even suspended; the construction can be obtained through, but is not limited to, experimental testing and simulation verification;

[0021] Estimate the working radius and lifting height that the crane will reach after completing the upper structure operation at the next time node; read the corresponding maximum lifting weight from the lifting performance table based on the working radius and lifting height;

[0022] Set a light load condition determination coefficient, which can be obtained through, but is not limited to, experimental testing and simulation verification; calculate the ratio of the lifting weight to the corresponding maximum lifting weight; determine whether the subsequent operation belongs to the light load condition based on whether the ratio is less than the light load condition determination coefficient: if yes, proceed to step 103; if no, it is determined that the operation exceeds the light load condition range, the state prediction is no longer applicable, the subsequent steps are interrupted, and other solutions are used for processing.

[0023] Step 104, Determine the compensation requirement, which specifically includes: taking the total weight of the crane G / n shared by each outrigger as the load distribution expectation, and establishing the optimal load model with the overall mechanical balance of the crane as the equation constraint, Formula 4;

[0024] Formula 4;

[0025] The theoretical optimal load of each outrigger after the upper loading operation at the next time node is calculated according to Formula 4. The theoretical optimal posture of the chassis is taken as follows: ;

[0026] Set the chassis tilt compensation threshold within the range of 0.1° to 1°. The triggering of the tilt compensation threshold is determined by any one of the estimated chassis tilt angles exceeding the value;

[0027] Set the load compensation threshold for the outriggers within the range of 20% to 50%. The load compensation threshold is triggered by first calculating the absolute value of the deviation between the estimated load of each outrigger at the next node and the theoretical optimal load of each outrigger after the corresponding loading operation at the next node, and dividing it by the expected load distribution to obtain the load deviation rate of each outrigger; the maximum value of the load deviation rate of each outrigger exceeds the load compensation threshold as a criterion.

[0028] The system detects whether the tilt angle compensation threshold or load compensation threshold is triggered for the next time node corresponding to the superstructure operation, and determines whether compensation control needs to be performed: if yes, then proceed to step 104; if no, then skip step 104, control the superstructure to operate according to the driver's instructions, and directly proceed to step 105.

[0029] Step 105, Synchronous Control of Operation and Compensation, specifically includes:

[0030] Based on the joint control matrix of load and deformation, the measured value and theoretical optimal value at the current moment, and the estimated value and theoretical optimal value at the next node, a global control equation of forward feedback composite and attitude-load coupling is constructed. Required outrigger base compensation ;

[0031] Formula 5;

[0032] In the formula, The load-bearing and deformation joint control matrix is ​​described above. Its measurement method is described in "A Leveling Control Method for a Multi-Point Support Platform ZL202110075160.2 / US12097737B2". It should be noted that the measurement of this load-bearing and deformation joint control matrix can also be performed before leaving the factory, but the extension degree of each outrigger should be consistent with the actual working conditions. The measurement scheme and physical mechanism of the load-bearing and deformation joint control matrix are completely different from those of the state prediction matrix in this application. The superscripts "c*, c, p*, p" of the parameters on the right side of the equation represent the theoretical optimal value of the current state, the measured value at the current moment, the theoretical optimal value of the next node prediction, and the next node prediction, respectively.

[0033] Subtracting the average value from the basic outrigger compensation amount yields the actual outrigger compensation amount.

[0034] Formula 6;

[0035] In formula 6, This refers to the compensation amount required for each outrigger to restore the chassis to geometric level and maintain the theoretically optimal load when completing the superstructure operation corresponding to the next time node.

[0036] The upper structure is controlled to operate according to instructions, and each outrigger is controlled to move synchronously according to the actual outrigger compensation amount, so that all outriggers complete the corresponding compensation at the same time as the upper structure completes the operation, that is, the upper structure operation and outrigger compensation are synchronously controlled within the corresponding time node interval.

[0037] Step 106, cyclically monitor driver commands: If the driver still inputs commands, then cyclically execute steps 102-106. The technical concept of this invention is: ① For the prediction model of the outrigger system, a statically indeterminate problem, it breaks through the fixed thinking of constructing deformation coordination conditions on top of the mechanical equilibrium equation to solve the outrigger deformation. Starting from the principle of superposition of linear systems, it constructs a matrix of the influence relationship between the unitized load and the chassis attitude and the outrigger load, i.e., the state prediction matrix, and then constructs a completely new state prediction equation that does not depend on the plane assumption and equivalent stiffness estimation. In principle, as long as the actual operation meets the light load condition described in this application, i.e., the outrigger does not become suspended, the above prediction gives an accurate solution. ② The calculation of the four factors in the outrigger compensation solution model (Formula 5) of this application is, in principle, based on the control concept of compensating for the tilt angle and load error at the next moment by performing "initial leveling" on the tilt angle and load error at the current moment, thus effectively reducing the accumulation of errors from the root. ③ In view of theoretical constraints and engineering practice, engineering limitations were made on light load conditions and load compensation thresholds to ensure that the above model can be used within a reliable constraint range.

[0038] The beneficial effects of this invention are as follows: First, for cranes with any number / type of legs, as long as the superstructure operation meets the light load condition limit, the state prediction equation can provide a prediction value far superior to that of the methods in prior art documents 2-3; second, based on the light load condition determination and compensation requirement determination, it provides a judgment result that conforms to engineering reality regarding whether the method of this application is applicable to future operation characteristics and whether active control of the outriggers is required; finally, based on the forward feedback composite and attitude-load coupled global control equation, the outrigger compensation amount is calculated, and synchronous control of superstructure operation and outrigger compensation is implemented. This achieves the goal of keeping the chassis close to horizontal in real time and the load of each leg close to the theoretical optimum, improving operation efficiency and stability. Attached Figure Description

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] Figure 1 This is a flowchart of the method for state prediction and control of a light-load truck crane according to the present invention;

[0041] Figure 2 This is a simulation model diagram of the state prediction and control method for light-load truck cranes according to the present invention.

[0042] Figure 3This is a flowchart of the state prediction matrix construction process for the state prediction and control method for light-load truck cranes of the present invention.

[0043] Figure 4 This is a flowchart of the load migration column vector construction for the state prediction and control method of a light-load truck crane according to the present invention.

[0044] Figure 5 This is a comparison diagram of the state prediction method and simulation verification of the state prediction and control method for light-load truck cranes of the present invention.

[0045] Figure 6 This is a diagram illustrating the 0°~45° slewing control effect of the state prediction and control method for light-load truck cranes according to the present invention.

[0046] Figure 7 This diagram illustrates the effect of the upward 45°~90° slewing control of the state prediction and control method for a light-load truck crane according to the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the following is combined with... Figure 1 The flowchart shown and Figure 2 The simulation model example of a 185-ton six-legged truck crane shown herein provides a further detailed explanation of the invention. It should be understood that the six-legged crane embodiment described herein is merely illustrative and not intended to limit the invention; the scope of this patent can be extended to crane platforms with any number of outriggers.

[0048] This invention discloses a method for state prediction and control of a lightly loaded truck crane, such as... Figure 2 As shown, the crane is driven by a luffing cylinder 1 for luffing, a slewing mechanism 2 for slewing, a telescopic mechanism 3 for extending and retracting the boom, and a winch mechanism 4 for raising and lowering the load 5. The crane has four or more outriggers 6 (n), with the foremost outrigger on the operator's left designated as outrigger 1, and numbers assigned from 2 to n in a counter-clockwise spiral. Each outrigger is equipped with a force sensor to measure its vertical load and a displacement sensor to measure its vertical displacement. The coordinate system is defined with the geometric center of the slewing mechanism as the origin, the x-axis parallel to the ground and pointing forward to the operator, the y-axis pointing to the operator's left, and the z-axis vertically upward. The longitudinal and transverse coordinates of each outrigger are as follows: The slewing mechanism has an attitude sensor fixed at its geometric center to measure the chassis tilt angles around the x and y axes; its characteristic is that, in the initial state, the outrigger system has fully or partially deployed and fixed the outrigger booms as needed, with each outrigger supporting the crane until the tires are completely suspended in the air, the load has been lifted off the ground, and initial leveling has been implemented through geometric horizontal and load equalization coupling, ready to commence upper-mounted operations such as hoisting, luffing, slewing, and winching. Figure 1The flowchart shown illustrates the following steps in the method for predicting and controlling the state of a lightly loaded truck crane:

[0049] Step 101, State Prediction, specifically includes: applying a force of 1 unit vertically downwards at the geometric center of the slewing mechanism, the unit value conforming to the standard of normalization; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively, using the attitude sensor and force sensor; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the first column of the (n+2)×3 dimensional matrix shown in Formula 1; then, first applying a torque of 1 unit around the x-axis, and then applying a torque of 1 unit around the y-axis, the unit value conforming to the standard of normalization, at the geometric center of the slewing mechanism; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the second and third columns of the (n+2)×3 dimensional matrix, until a state prediction matrix is ​​constructed. ;

[0050] Formula 1;

[0051] The unitization of the vertical force and torque is carried out independently. The standard is that after the corresponding value is applied, the load of more than half of the outriggers increases or decreases by more than 5%, and there is no situation where the outrigger load becomes zero or the outrigger is suspended. This is the basis for evaluation. The measurement of the state prediction matrix can be carried out before leaving the factory, but the extension degree of each outrigger arm should be consistent with the actual working conditions.

[0052] For example, Figure 2 The 185-ton six-legged truck crane shown can be simulated using the above method to obtain its state prediction matrix. .

[0053] Step 102: Calculate the total weight G and centroid coordinates of the crane at the current moment. ; Detect the lifting, luffing, and slewing commands input by the operator, and control the crane to temporarily suspend the corresponding upper-body operations; Estimate the total weight of the crane after the corresponding upper-body operations at the next time point. and new centroid coordinates The increments of vertical force, torque around the x-axis, and torque around the y-axis are decomposed from the migration data of the new centroid coordinates to construct a load migration column vector. Furthermore, the vertical force and torque in the load migration column vector should be normalized in the same way as above; the order of the load migration column vectors is consistent with the order of the column vectors of the state prediction matrix; if the order of the three columns of the state prediction matrix is ​​changed as a whole, the order of the load migration column vectors needs to be changed accordingly.

[0054] Based on the state prediction matrix and the load migration column vector, a state prediction equation is constructed, Equation 2, to solve for the increase in chassis tilt angle and outrigger load caused by the centroid migration generated by the corresponding superstructure operation.

[0055] Formula 2;

[0056] If the upper-mounted operation does not involve the loading and unloading of the load, the first column of the state prediction matrix and the first row of the load migration column vector can be deleted to construct a simplified state prediction equation, Formula 3;

[0057] Formula 3;

[0058] The increments of the chassis tilt angle and outrigger load are respectively compared with the measured value of the chassis tilt angle at the current moment. and the current measured value of outrigger load Add them together to obtain the estimated chassis tilt angle at the next time point. Outrigger load estimate .

[0059] For example, targeting Figure 2 The 185-ton six-leg truck crane shown was subjected to finite element simulation calculations when the superstructure was at 0° and when it rotated 45°. The results show the changes in chassis tilt angle and outrigger load as the superstructure rotates from 0° to 45°. Figure 5 The data in the first column. According to Formula 3, the change in chassis tilt angle and outrigger load when the chassis rotates from 0° to 45° can also be calculated, such as... Figure 5 The data in the second column. The error rates of the two are as follows: Figure 5 The data in column 3 shows that the tilt angle error is less than 3.7% and the load error is less than 14%. Further calculations using simulation and prediction models can be performed to determine the chassis tilt angle and outrigger load when the superstructure rotates to 45°, as shown below. Figure 5 The data in columns 4 and 5. The error rates of the two are as follows: Figure 5 The data in column 6 shows that the tilt angle error is less than 3.8% and the load error is less than 4%. This evidence confirms that the state prediction results given in steps 101 and 102 are valid and accurate.

[0060] Step 103, light load condition determination, specifically includes: constructing a crane lifting performance table under the current outrigger boom extension degree, wherein the maximum lifting weight of the lifting performance table must cover the extreme situation where any outrigger has zero load or is even suspended; the construction can be obtained through, but is not limited to, experimental testing and simulation verification;

[0061] Estimate the working radius and lifting height that the crane will reach after completing the upper structure operation at the next time node; read the corresponding maximum lifting weight from the lifting performance table based on the working radius and lifting height;

[0062] Set a light load condition determination coefficient, which can be obtained through, but is not limited to, experimental testing and simulation verification; calculate the ratio of the lifting weight to the corresponding maximum lifting weight; determine whether the subsequent operation belongs to the light load condition based on whether the ratio is less than the light load condition determination coefficient: if yes, proceed to step 103; if no, it is determined that the operation exceeds the light load condition range, the state prediction is no longer applicable, the subsequent steps are interrupted, and other solutions are used for processing.

[0063] Step 104, Determine the compensation requirement, which specifically includes: taking the total weight of the crane G / n shared by each outrigger as the load distribution expectation, and establishing the optimal load model with the overall mechanical balance of the crane as the equation constraint, Formula 4;

[0064] Formula 4;

[0065] The theoretical optimal load of each outrigger after the upper loading operation at the next time node is calculated according to Formula 4. The theoretical optimal posture of the chassis is taken as follows: ;

[0066] Set the chassis tilt compensation threshold within the range of 0.1° to 1°. The triggering of the tilt compensation threshold is determined by any one of the estimated chassis tilt angles exceeding the value;

[0067] Set the load compensation threshold for the outriggers within the range of 20% to 50%. The load compensation threshold is triggered by first calculating the absolute value of the deviation between the estimated load of each outrigger at the next node and the theoretical optimal load of each outrigger after the corresponding loading operation at the next node, and dividing it by the expected load distribution to obtain the load deviation rate of each outrigger; the maximum value of the load deviation rate of each outrigger exceeds the load compensation threshold as a criterion.

[0068] The system detects whether the tilt angle compensation threshold or load compensation threshold is triggered for the next time node corresponding to the superstructure operation, and determines whether compensation control needs to be performed: if yes, then proceed to step 104; if no, then skip step 104, control the superstructure to operate according to the driver's instructions, and directly proceed to step 105.

[0069] Step 105, Synchronous Control of Operation and Compensation, specifically includes:

[0070] Based on the joint control matrix of load and deformation, the measured value and theoretical optimal value at the current moment, and the estimated value and theoretical optimal value at the next node, a global control equation of forward feedback composite and attitude-load coupling is constructed. Required outrigger base compensation ;

[0071] Formula 5;

[0072] In the formula, The load-bearing and deformation joint control matrix is ​​described above. Its measurement method is described in "A Leveling Control Method for a Multi-Point Support Platform ZL202110075160.2 / US12097737B2". It should be noted that the measurement of this load-bearing and deformation joint control matrix can also be performed before leaving the factory, but the extension degree of each outrigger should be consistent with the actual working conditions. The measurement scheme and physical mechanism of the load-bearing and deformation joint control matrix are completely different from those of the state prediction matrix in this application. The superscripts "c*, c, p*, p" of the parameters on the right side of the equation represent the theoretical optimal value of the current state, the measured value at the current moment, the theoretical optimal value of the next node prediction, and the next node prediction, respectively.

[0073] Subtracting the average value from the basic outrigger compensation amount yields the actual outrigger compensation amount.

[0074] Formula 6;

[0075] In formula 6, This refers to the compensation amount required for each outrigger to restore the chassis to geometric level and maintain the theoretically optimal load when completing the superstructure operation corresponding to the next time node.

[0076] The upper structure is controlled to operate according to instructions, and each outrigger is controlled to move synchronously according to the actual outrigger compensation amount, so that all outriggers complete the corresponding compensation at the same time as the upper structure completes the operation, that is, the upper structure operation and outrigger compensation are synchronously controlled within the corresponding time node interval.

[0077] For example, Figure 2 The simulated load-bearing and deformation joint control matrix of the 185-ton six-legged truck crane shown is specifically valued as follows: Based on this combined load-bearing and deformation control matrix, and according to... Figure 6The current (0°) measured value and theoretical optimal value, along with the estimated value and theoretical optimal value when the superstructure rotates to 45°, allow for the calculation of the compensation amounts for each outrigger, as shown in column 5. Applying this data to the outriggers of the simulation model to implement synchronized control of the superstructure operation and outrigger compensation, the chassis tilt angle and outrigger loads are shown in column 6. Clearly, the chassis tilt angle has improved from the estimated (-0.328°, -0.073°) to (0.021°, -0.006°), and the outrigger loads are also closer to the theoretical optimal loads in column 3. This evidence confirms that the crane chassis stability has been effectively improved when the superstructure rotates to 45°.

[0078] Furthermore, relying on this joint control matrix of bearing capacity and deformation, and according to... Figure 7 The current (45°) measured value and theoretical optimal value, along with the estimated value and theoretical optimal value when the superstructure rotates to 90°, allow for the calculation of the compensation amounts for each outrigger, as shown in column 5. Applying this data to the outriggers of the simulation model to implement synchronized control of superstructure operation and outrigger compensation, the chassis tilt angle and outrigger loads are shown in column 6. Clearly, the chassis tilt angle has improved from the estimated (-0.103°, -0.177°) to (-0.015°, 0.003°), while the outrigger loads are also closer to the theoretical optimal loads in column 3. This evidence confirms that the crane chassis stability is effectively improved when the superstructure rotates to 90°. While maintaining a near-horizontal chassis, the outrigger loads approach the theoretical optimal, thus improving operational efficiency and stability. It should be noted that the two active controls at 45° and 90° in the example are only examples. In actual operation, the control interval can be freely adjusted, thereby achieving real-time attitude and load stability throughout the entire cycle, which significantly improves operation efficiency and safety.

[0079] Step 106, cyclically monitor driver commands: If the driver still has commands to input, then cyclically execute steps 102 to 106.

[0080] Finally, it should be noted that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. This invention discloses a method for state prediction and control of a light-load truck crane. The crane is driven by a luffing cylinder for luffing, a slewing mechanism for slewing, a telescopic mechanism for extending and retracting the boom, and a winch mechanism for raising and lowering the load. The crane has four or more outriggers (n), with the outrigger furthest to the left of the driver designated as outrigger 1, and numbers assigned from 2 to n in a counter-clockwise spiral. Each outrigger is equipped with a force sensor to measure its vertical load and a displacement sensor to measure its vertical displacement. The coordinate system of the method is defined with the geometric center of the slewing mechanism as the origin, the x-axis parallel to the ground and pointing forward to the driver, the y-axis pointing to the driver's left, and the z-axis vertically upward. The longitudinal and transverse coordinates of each outrigger are defined as follows: The geometric center of the rotary mechanism is fixed with an attitude sensor for measuring the tilt angle of the chassis around the x-axis and y-axis; characterized in that, In the initial state, the outrigger system has been fully or partially deployed and secured as needed. The crane is supported by the outriggers until the tires are completely suspended in the air. The load has been lifted off the ground, and initial leveling has been performed using geometric leveling and load equalization coupling. Lifting, luffing, slewing, and winching operations are about to commence, including the following operating steps: Step 101, State Prediction, specifically includes: applying a force of 1 unit vertically downwards at the geometric center of the slewing mechanism, the unit value conforming to the standard of normalization; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively, using the attitude sensor and force sensor; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the first column of the (n+2)×3 dimensional matrix shown in Formula 1; then, first applying a torque of 1 unit around the x-axis, and then applying a torque of 1 unit around the y-axis, the unit value conforming to the standard of normalization, at the geometric center of the slewing mechanism; measuring the tilt angle increment of the chassis around the x-axis and y-axis, and the load increment of each outrigger, respectively; sequentially placing the tilt angle increment and load increment into the first row to the nth row of the second and third columns of the (n+2)×3 dimensional matrix, until a state prediction matrix is ​​constructed. ; Official 1; The unitization of the vertical force and torque is carried out independently. The standard is that after the corresponding value is applied, the load of more than half of the outriggers increases or decreases by more than 5%, and there is no outrigger load becoming zero or the outriggers being suspended. This is the basis for evaluation. The measurement of the state prediction matrix can be carried out before leaving the factory, but the extension degree of each outrigger arm should be consistent with the actual working conditions. Step 102: Calculate the total weight G and centroid coordinates of the crane at the current moment. ; Detect the lifting, luffing, and slewing commands input by the driver, and control the crane to temporarily suspend the corresponding upper-body operations; Estimate the crane's total weight G' and new center of gravity coordinates after the corresponding upper-body operations at the next time node. The increments of vertical force, torque around the x-axis, and torque around the y-axis are decomposed from the migration data of the new centroid coordinates to construct a load migration column vector. Furthermore, the vertical force and torque in the load migration column vector should be normalized in the same way as above; the order of the load migration column vectors is consistent with the order of the column vectors of the state prediction matrix; if the order of the three columns of the state prediction matrix is ​​changed as a whole, the order of the load migration column vectors needs to be changed accordingly. Based on the state prediction matrix and the load migration column vector, a state prediction equation is constructed, Equation 2, to solve for the increase in chassis tilt angle and outrigger load caused by the centroid migration generated by the corresponding superstructure operation. Official 2; If the upper-mounted operation does not involve the loading and unloading of the load, the first column of the state prediction matrix and the first row of the load migration column vector can be deleted to construct a simplified state prediction equation, Formula 3; Official 3; The increments of the chassis tilt angle and outrigger load are respectively compared with the measured value of the chassis tilt angle at the current moment. and the current measured value of outrigger load Add them together to obtain the estimated chassis tilt angle at the next time point. Outrigger load estimate ; Step 103, light load condition determination, specifically includes: constructing a crane lifting performance table under the current outrigger boom extension degree, wherein the maximum lifting weight of the lifting performance table must cover the extreme situation where any outrigger has zero load or is even suspended; the construction can be obtained through, but is not limited to, experimental testing and simulation verification; Estimate the working radius and lifting height that the crane will reach after completing the upper structure operation at the next time node; read the corresponding maximum lifting weight from the lifting performance table based on the working radius and lifting height; Set a light load condition judgment coefficient, which can be constructed through, but is not limited to, experimental testing and simulation verification; calculate the ratio of the lifting weight to the corresponding maximum lifting weight; determine whether the subsequent operation belongs to the light load condition based on whether the ratio is less than the light load condition judgment coefficient: if yes, then execute step 103; if no, then it is determined that it exceeds the light load condition range, the state prediction is no longer applicable, the execution of subsequent steps is interrupted, and other solutions are used for processing. Step 104, Determine the compensation requirement, which specifically includes: taking the total weight of the crane G / n shared by each outrigger as the load distribution expectation, and establishing the optimal load model with the overall mechanical balance of the crane as the equation constraint, Formula 4; Official 4; The theoretical optimal load of each outrigger after the upper loading operation at the next time node is calculated according to Formula 4. The theoretical optimal posture of the chassis is taken as follows: ; Set the chassis tilt compensation threshold within the range of 0.1° to 1°. The triggering of the tilt angle compensation threshold is determined by any one of the estimated chassis tilt angle values ​​exceeding the specified value; Set the load compensation threshold for the outriggers within the range of 20% to 50%. The load compensation threshold is triggered by first calculating the absolute value of the deviation between the estimated load of each outrigger at the next node and the theoretical optimal load of each outrigger after the corresponding loading operation at the next node, and dividing it by the expected load distribution to obtain the load deviation rate of each outrigger; the maximum value of the load deviation rate of each outrigger exceeds the load compensation threshold as a criterion. The system detects whether the tilt angle compensation threshold or load compensation threshold is triggered for the next time node corresponding to the superstructure operation, and determines whether compensation control needs to be performed: if yes, then proceed to step 104; if no, then skip step 104, control the superstructure to operate according to the driver's instructions, and directly proceed to step 105. Step 105, Synchronous Control of Operation and Compensation, specifically includes: Based on the joint control matrix of load and deformation, the measured value and theoretical optimal value at the current moment, and the estimated value and theoretical optimal value at the next node, a global control equation of forward feedback composite and attitude-load coupling is constructed. Required outrigger base compensation ; Official 5; In the formula, The bearing and deformation joint control matrix is ​​given; the superscripts "c*, c, p*, p" of each parameter on the right side of the equation represent the theoretical optimal value of the current state, the measured value at the current moment, the theoretical optimal value of the estimated value of the next node, and the estimated value of the next node, respectively. Subtracting the average value from the basic outrigger compensation amount yields the actual outrigger compensation amount. Official 6; In formula 6, This refers to the compensation amount required for each outrigger to restore the chassis to geometric level and maintain the theoretically optimal load when completing the superstructure operation corresponding to the next time node. Control the upper structure to operate according to the instructions, and at the same time control each outrigger to move synchronously according to the actual outrigger compensation amount, so that when the upper structure completes the operation, all outriggers complete the corresponding compensation, that is, complete the synchronous control of the upper structure operation and outrigger compensation within the corresponding time node interval. Step 106, cyclically monitor driver commands: If the driver still has commands to input, then cyclically execute steps 102 to 106.

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