Multi-oil-cylinder load self-adaptive step ladder folding and unfolding cooperative control method and system

Abstract

The invention provides a multi-oil-cylinder load self-adaptive step ladder folding and unfolding cooperative control method and system, is applied to an upper and lower rotor intelligent step ladder in a drainage basin power station machine pit, and aims to solve the problems of insufficient synchronization precision, poor load adaptability, weak anti-interference capability, parameter uncertainty and weak constraint rigidity of oil cylinders on two sides in step ladder folding and unfolding. According to the method, based on a direct / indirect adaptive robust control strategy (ESO-DIARC) of an extended state observer, step ladder load deviation and shunting errors are observed based on ESO, and parameter estimation and observation values are fused, so that a better parameter estimation effect and more accurate feed-forward model compensation are realized, the precision and response speed of dynamic flow distribution synchronous control are further improved, and the dynamic flow distribution synchronous control method is suitable for large-scale popularization and application. And the step ladder is ensured to be folded and unfolded safely without deflection to meet the operation and maintenance requirements of watershed power stations.

Description

Technical Field

[0001] This invention relates to the field of watershed power plant equipment control technology, specifically to a multi-cylinder load adaptive expansion and collaborative control method for an intelligent step ladder for upper and lower rotors in a watershed power plant pit. Background Technology

[0002] The intelligent staircase for the upper and lower rotors inside the generator pit of the watershed power station is a key passage for unit maintenance and operation. Its folding and unfolding action relies on the coordinated drive of hydraulic cylinders on both sides (such as switching from vertical retraction to horizontal unfolding). There are two major problems in the folding and unfolding process of the staircase: First, the load changes dynamically. The center of gravity of the staircase itself shifts with its position and may bear additional loads from maintenance personnel and tools, resulting in nonlinear fluctuations in the load on the hydraulic cylinders on both sides. Second, the structural rigidity is limited. If the synchronous error of the displacement of the hydraulic cylinders on both sides exceeds 0.5mm, it will cause the staircase to deflect or tilt, and in severe cases, cause structural deformation or fracture.

[0003] Current mainstream hydraulic cylinder synchronization control technologies mainly rely on traditional PID and ordinary DIARC, but they still have significant shortcomings: Poor load adaptability: Traditional PID relies on fixed parameters and cannot cope with dynamic loads; the online parameter estimation process of traditional direct / indirect adaptive robust control strategies is usually slow, and the impact on the feedforward model is small for slowly varying parameters or parameters with small amplitude changes, such as the oil elastic modulus and viscous damping coefficient in the system. However, drastic changes in the load deviation of the dual cylinders will directly cause serious flow splitting errors in the dynamic flow distribution synchronization system, thereby causing distortion of the feedforward compensation model.

[0004] Weak anti-interference capability: There are interferences such as vibration and oil temperature changes in the power plant pit. Ordinary DIARC lags in estimating slowly changing parameters such as oil elastic modulus and viscous damping, and cannot quickly capture sudden interferences such as load deviation and synchronization valve diversion error, resulting in a decrease in synchronization accuracy. Therefore, it is urgent to design a collaborative control algorithm that combines load adaptation, fast anti-interference, and parameter safety constraints to solve the pain point of synchronous control in intelligent staircase folding and unfolding. Summary of the Invention

[0005] In view of this, the main objective of this invention is to provide a multi-cylinder load adaptive collaborative control method and system for staircase folding and unfolding. This method is based on the direct / indirect adaptive robust control strategy (ESO-DIARC) of the extended state observer to solve the problem of synchronous control of the cylinders on both sides during the staircase folding and unfolding process, thus ensuring the structural safety of the staircase and the safety of maintenance personnel.

[0006] To achieve the above-mentioned technical features, the objective of this invention is as follows: a multi-cylinder load adaptive step-ladder expansion cooperative control method, the method being based on a direct / indirect adaptive robust control strategy using an expanded state observer, comprising the following steps: Step 1: Establish a dynamic model of the hydraulic cylinder, and design a controller based on the dynamic model of the hydraulic cylinder. The controller includes a feedforward model compensation term, a fast dynamic compensation term, a nonlinear feedback term, and a linear feedback term. Step 2: Input the desired displacement of the hydraulic cylinder and the parameters after model-based online parameter estimation and extended observer processing into the feedforward model compensation term to obtain the feedforward model compensation part. At the same time, input the displacement error and pressure error of the hydraulic cylinder into the fast dynamics compensation term, nonlinear feedback term and linear feedback term in real time, respectively. Step 3: Obtain the flow signal based on the feedforward model compensation term, fast dynamics compensation term, nonlinear feedback term, and linear feedback term. Then, complete the valve control current signal through function mapping of the flow signal and current signal, thereby achieving high-precision control of the hydraulic cylinder displacement and realizing displacement control closed loop.

[0007] Preferably, the dynamic model of the hydraulic cylinder is as follows: (1) (2) (3) (4) (5) (6) In the formula, This refers to the pressure in the hydraulic cylinder's inlet chamber. This refers to the pressure in the return oil chamber of the hydraulic cylinder. This refers to the effective working area of ​​the hydraulic cylinder piston rod. The total mass of the hydraulic cylinder piston rod and directly connected components; This refers to the displacement of the hydraulic cylinder piston rod. The viscous damping coefficient of the hydraulic cylinder piston rod; It is an external load force; External disturbances and modeling errors; The elastic modulus of hydraulic oil; The internal leakage coefficient of the hydraulic cylinder; This is for the error in the export flow rate; and Given a function; , These are the viscous damping coefficients of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. The valve orifice flow coefficient; Uncertainty terms for force modeling; Model uncertainties for the flow; For parameters; and These are the minimum and maximum values ​​of the parameter, respectively. This refers to the total volume of the hydraulic cylinder rod chamber; This refers to the basic volume of the hydraulic cylinder rod cavity; For force loading deviation; ; ; ; ; ; ; ; , , , , , , , , They are respectively , , , , , , , , .

[0008] Preferably, the feedforward model compensation term, fast dynamics compensation term, nonlinear feedback term, and linear feedback term are specifically as follows: Pressure Error Expected Input It consists of the following forms: (7) Flow error expected input Expressed in a similar form: (8) in, For linear feedback gain; This is the compensation term for the pressure error feedforward model; This is a rapid dynamic compensation term for pressure error; This is a linear feedback term for pressure error; This is a nonlinear feedback term for pressure error; For linear feedback gain; Additional compensation terms for the design of the inversion strategy; and These are the weighting coefficients; This is the compensation term for the flow error feedforward model; This is a fast dynamic compensation term for flow error; For the linear feedback term of flow error; This is a nonlinear feedback term for flow error; , It is an arbitrarily small design parameter; This refers to the displacement synchronization error; For pressure difference; For pressure error; These are parameter estimates; and They are respectively: ; ; This is the gain coefficient; and These are the maximum values ​​of the uncertainty terms in force modeling and flow modeling, respectively. This is the computable part of the first derivative of the pressure. Define sliding mode function : (9) Error Dynamics The expression form is: (10) (11) (12) In the formula, For the estimated proportional gain; for The known boundary function; This is the gain coefficient; This is the incalculable part of the first derivative of the pressure; This is the projection function.

[0009] Preferably, the dual-cylinder load deviation in the system and shunting error It is the main disturbance factor affecting feedforward compensation. To achieve fast tracking of it, the following extended state observer is constructed: (13) In the formula, They are respectively as well as Estimated state variables after system expansion; , The observer parameters determine the observer's tracking frequency and observation accuracy.

[0010] Preferably, the observations of the extended state observer , To balance the speed of the extended state observer with the true-value convergence of the online least squares method, data fusion of the two estimates is necessary. When disturbances occur, the extended state observer enables the parameter estimates to quickly approximate the true values. As the tracking error decreases, the online least squares parameter estimator plays a major role, ensuring the convergence of the parameter estimates to the true values. The fused data is then used to... Assign to Participate in feedforward compensation.

[0011] Preferably, the fused Assign to Specifically: (14) Guaranteed , .

[0012] Another aspect of the present invention provides a multi-cylinder load adaptive staircase expansion cooperative control system, the system being used to implement any one of the cooperative control methods described above, comprising: Sensing unit: includes laser displacement sensor and pressure sensor, providing real-time data input for the algorithm; Control unit: includes a PLC controller and a collaborative control algorithm, wherein the PLC controller supports real-time calculation; The actuator includes an electro-hydraulic proportional valve and a double-rod hydraulic cylinder. The electro-hydraulic proportional valve is used to output flow according to a static mapping of "flow rate - current", and the double-rod hydraulic cylinder is used to drive the step ladder to unfold.

[0013] Preferably, the control unit executes the corresponding control process based on the core algorithms of the load adaptive parameter estimation, ESO, data fusion and hierarchical collaborative control modules.

[0014] Preferably, the load adaptive parameter estimation module achieves safe and accurate parameter estimation by combining a projective adaptive law with the least squares method. The projective adaptive law is passed through Functional constraints exist Within the specified range, avoid exceeding parameter limits; The least squares method is defined by... , ,through After filtering, a linear regression equation is constructed. Accurately estimate slowly varying parameters; in, This is a parameter derived from the elastic modulus of oil.

[0015] Preferably, the ESO module implements simultaneous observation of state and disturbance, and its observation equation includes displacement error observation: ; ; Pressure error observation: ; in , Quickly capture load deviation With shunt error .

[0016] Preferably, the data fusion module fuses the accuracy of parameter estimation with the speed of ESO, and the fusion formula is as follows: ; in The load force parameters estimated by the least squares method For ESO-observed load deviation, ensure hour It converges to the true value, balancing accuracy and speed.

[0017] Preferably, the hierarchical collaborative control module adopts displacement-pressure hierarchical control logic to achieve collaborative control; Displacement synchronization layer: target ,definition , Feedforward compensation Rapid compensation Linear feedback Nonlinear robust terms composition; Pressure difference tracking layer target ,definition , Feedforward compensation , Rapid compensation Linear feedback Nonlinear robust terms composition.

[0018] Preferably, the execution output will Convert to proportional valve control current This drives the hydraulic cylinder to move.

[0019] Preferably, the control process specifically includes: Step 1, Initialization: Power on and initialize algorithm parameters and sensor zero point; Step 2, Data Acquisition: The sensing unit acquires data in real time. / , / The data is transmitted to the control unit. Step 3, Error Calculation: Calculate , and rate of change , ; Step 4, Parameter and Disturbance Estimation: Output of the Load Adaptive Parameter Estimation Module ESO output / Data fusion module output ; Step 5, Control Variable Calculation: Calculated by the hierarchical collaborative control module. and convert to ; Step 6, Execution and Feedback: The execution unit drives the hydraulic cylinder and repeats steps 2-5 until the folding is complete.

[0020] The present invention has the following beneficial effects: This invention provides a multi-cylinder load adaptive step-folding cooperative control method, which can achieve the high-precision synchronization and fast response drive requirements of dynamic flow distribution synchronization system. The maximum synchronization error of dual cylinders is less than 0.3mm, the average error is less than 0.1mm, and it has good anti-interference ability, which far meets the actual drive application requirements. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a diagram of the mobile trolley used for transporting stairs.

[0023] Figure 2 This is a structural diagram of the step ladder tilting mechanism.

[0024] Figure 3 This is a schematic diagram of a dynamic flow distribution dual-cylinder synchronous hydraulic system.

[0025] Figure 4 This is a block diagram of the principle of the multi-cylinder load adaptive step ladder expansion cooperative control algorithm.

[0026] Figure 5 This is a curve showing the synchronization error during the adaptive multi-cylinder ladder deployment process.

[0027] Figure 6 This is a curve showing the synchronization error during the retraction process of a multi-cylinder adaptive ladder.

[0028] Figure 7 The flowchart shows the entire deployment process of the multi-cylinder load adaptive step ladder. Detailed Implementation

[0029] The present invention will be further described in detail below through specific embodiments. These embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way.

[0030] Example 1: like Figure 6 This embodiment provides a multi-cylinder load adaptive step-ladder expansion cooperative control method, including: a direct / indirect adaptive robust control strategy based on an expanded state observer (ESO-DIARC). First, a hydraulic cylinder dynamics model is established, and a controller is designed based on this model. The controller includes a feedforward model compensation term, a fast dynamics compensation term, a nonlinear feedback term, and a linear feedback term. The desired displacement of the hydraulic cylinder and the parameters processed by the model-based online parameter estimation and the expanded observer are input into the feedforward model compensation term to obtain the feedforward model compensation part. Simultaneously, the displacement error and pressure error of the hydraulic cylinder are input into the fast dynamics compensation term, the nonlinear feedback term, and the linear feedback term in real time, respectively. The flow signal is obtained based on the feedforward model compensation term, the fast dynamics compensation term, the nonlinear feedback term, and the linear feedback term. Then, the valve control current signal is obtained through a function mapping between the flow signal and the current signal, thereby achieving high-precision control of the hydraulic cylinder displacement and realizing a closed-loop displacement control.

[0031] Furthermore, the specific dynamic model of the hydraulic cylinder is as follows: (1) (2) (3) (4) (5) (6) In the formula, This refers to the pressure in the hydraulic cylinder's inlet chamber. This refers to the pressure in the return oil chamber of the hydraulic cylinder. This refers to the effective working area of ​​the hydraulic cylinder piston rod. The total mass of the hydraulic cylinder piston rod and directly connected components; This refers to the displacement of the hydraulic cylinder piston rod. The viscous damping coefficient of the hydraulic cylinder piston rod; It is an external load force; External disturbances and modeling errors; The elastic modulus of hydraulic oil; The internal leakage coefficient of the hydraulic cylinder; This is for the error in the export flow rate; and Given a function; , These are the viscous damping coefficients of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. The valve orifice flow coefficient; Uncertainty terms for force modeling; Model uncertainties for the flow; For parameters; and These are the minimum and maximum values ​​of the parameter, respectively. This refers to the total volume of the hydraulic cylinder rod chamber; This refers to the basic volume of the hydraulic cylinder rod cavity; For force loading deviation; ; ; ; ; ; ; ; , , , , , , , , They are respectively , , , , , , , , .

[0032] Furthermore, the feedforward model compensation term, fast dynamics compensation term, nonlinear feedback term, and linear feedback term are specifically as follows: Pressure Error Expected Input It consists of the following forms: (7) Flow error expected input Expressed in a similar form: (8) in, For linear feedback gain; This is the compensation term for the pressure error feedforward model; This is a rapid dynamic compensation term for pressure error; This is a linear feedback term for pressure error; This is a nonlinear feedback term for pressure error; For linear feedback gain; Additional compensation terms for the design of the inversion strategy; and These are the weighting coefficients; This is the compensation term for the flow error feedforward model; This is a fast dynamic compensation term for flow error; For the linear feedback term of flow error; This is a nonlinear feedback term for flow error; , It is an arbitrarily small design parameter; This refers to the displacement synchronization error; For pressure difference; For pressure error; These are parameter estimates; and They are respectively: ; ; This is the gain coefficient; and These are the maximum values ​​of the uncertainty terms in force modeling and flow modeling, respectively. Define sliding mode function : (9) Error Dynamics The expression form is: (10) (11) (12) In the formula, For the estimated proportional gain; for The known boundary function; This is the gain coefficient; This is the incalculable part of the first derivative of the pressure; This is the projection function.

[0033] Furthermore, the dual-cylinder load deviation in the system and shunting error It is the main disturbance factor affecting feedforward compensation. To achieve fast tracking of it, the following extended state observer is constructed: (13) In the formula, They are respectively as well as Estimated state variables after system expansion; , The observer parameters determine the observer's tracking frequency and observation accuracy.

[0034] Furthermore, the observations of the extended state observer , To balance the speed of the extended state observer with the true-value convergence of the online least squares method, data fusion of the two estimates is necessary. When disturbances occur, the extended state observer enables the parameter estimates to quickly approximate the true values. As the tracking error decreases, the online least squares parameter estimator plays a major role, ensuring the convergence of the parameter estimates to the true values. The fused data is then used to... Assign to It participates in feedforward compensation. Therefore, the following formula is designed: (14) Guaranteed , .

[0035] Example 2: This embodiment provides a multi-cylinder load adaptive staircase expansion and contraction cooperative control system. The system is used to implement any one of the cooperative control methods described above, including: Sensing unit: includes laser displacement sensor and pressure sensor, providing real-time data input for the algorithm; Control unit: includes a PLC controller and a collaborative control algorithm, wherein the PLC controller supports real-time calculation; The actuator includes an electro-hydraulic proportional valve and a double-rod hydraulic cylinder. The electro-hydraulic proportional valve is used to output flow according to a static mapping of "flow rate - current", and the double-rod hydraulic cylinder is used to drive the step ladder to unfold.

[0036] Furthermore, the control unit executes the corresponding control process based on the core algorithms of the load adaptive parameter estimation, ESO, data fusion, and hierarchical collaborative control modules.

[0037] Module 1: The load adaptive parameter estimation module: By combining the projective adaptive law and the least squares method, it achieves safe and accurate parameter estimation; The projective adaptive law is passed through Functional constraints exist Within the specified range, avoid exceeding parameter limits; The least squares method is defined by... , ( (A parameter derived from the elastic modulus of oil), after After filtering, a linear regression equation is constructed. Accurate estimation of slowly varying parameters (such as...) ); Module 2: The ESO module realizes synchronous observation of "state + disturbance", and its observation equation includes displacement error observation: ; ; Pressure error observation: ; in , Quickly capture load deviation With shunt error .

[0038] Module 3: The data fusion module integrates the "accuracy of parameter estimation" and the "speed of ESO". The fusion formula is as follows: ; in The load force parameters estimated by the least squares method For ESO-observed load deviation, ensure hour It converges to the true value, balancing accuracy and speed.

[0039] Module 4: The hierarchical collaborative control module adopts displacement-pressure hierarchical control logic to achieve collaborative control; Displacement synchronization layer: target ,definition ( ), By feedforward compensation ( ), rapid compensation ( ), linear feedback ( , ), nonlinear robust terms ( Composition; Pressure difference tracking layer target ,definition , By feedforward compensation ( , , ), rapid compensation ( ), linear feedback ( , ), nonlinear robust terms ( )composition; Module 5: The execution output will Convert to proportional valve control current (4-20mA) drives the hydraulic cylinder to operate.

[0040] Example 3: The control process specifically includes: Step 1, Initialization: Power-on initialization of algorithm parameters ( , , (etc.) and sensor zero point; Step 2, Data Acquisition: The sensing unit acquires data in real time. / , / The data is transmitted to the control unit. Step 3, Error Calculation: Calculate , and rate of change , ; Step 4, Parameter and Disturbance Estimation: Output of the Load Adaptive Parameter Estimation Module ESO output / Data fusion module output ; Step 5, Control Variable Calculation: Calculated by the hierarchical collaborative control module. and convert to ; Step 6, Execution and Feedback: The execution unit drives the hydraulic cylinder and repeats steps 2-5 until the folding is complete.

[0041] Example 4: Figure 1 This diagram shows the assembly of a mobile trolley for transporting stairs. It consists of 1. a staircase tilting mechanism, 2. a tool and document box, 3. a control box, 4. a chassis, and 5. a hydraulic system. The chassis is the supporting structure, with the staircase support platform fixed to the top of the chassis to house the staircase tilting mechanism. The tool and document box stores maintenance tools and debugging documents. The control box contains a control board and algorithm module. The hydraulic system provides power to subsequent mechanisms, thus enabling the overall trolley to bear and move the stairs.

[0042] Figure 2 This is a structural diagram of the staircase tilting mechanism, consisting of 1 hydraulic cylinder, 2 connecting rods, and 3 bases. The tilting frame is connected to... Figure 1 The support platform is hinged, allowing it to be flipped; the seats are symmetrically fixed on both sides of the support platform for mounting hydraulic cylinders; the two hydraulic cylinders have a double-rod structure, and the piston rods are hydraulically driven to extend and retract synchronously, driving the flipping frame to unfold and retract the ladder, ensuring stable unfolding and retraction.

[0043] Figure 3 The schematic diagram of the dual-cylinder synchronous hydraulic principle for dynamic flow distribution is the core hydraulic circuit for the synchronous dual-cylinder drive of the stair folding mechanism. It consists of 1. inlet filter, 2. solenoid directional valve, 3. bidirectional speed control valve, 4. flow divider and collector, 5. shut-off valve, 6. proportional directional valve, 7. drive hydraulic cylinders (two in total, corresponding to the drive cylinders on both sides of the stair folding mechanism), 8. displacement sensor, 9. pressure sensor, and 10. pressure gauge. The connection relationship and working logic of each component are adapted to the stair folding requirements. The specific implementation details are as follows: The electromagnetic directional valve is a three-position four-way electromagnetic directional valve (with an O-type function in the middle position). Its outlet is connected to a bidirectional speed control valve to control the on / off state and flow direction of hydraulic oil, enabling the switching between the deployment and retraction of the ladder. The bidirectional speed control valve is connected in series between the electromagnetic directional valve and the flow divider / manufacturer to regulate the total flow entering the dual-cylinder circuit, controlling the extension and retraction speed of the drive hydraulic cylinders to meet operational safety requirements. The flow divider / manufacturer is an equal-volume flow divider type, with its inlet connected to the outlet of the bidirectional speed control valve. The two outlets are connected to the rodless chambers of the two drive hydraulic cylinders via pipelines. Its core function is to evenly distribute the hydraulic oil output from the bidirectional speed control valve to the two drive hydraulic cylinders, providing a basic flow guarantee for dual-cylinder synchronization. The proportional directional valve is connected in series between the flow divider / manufacturer and the drive hydraulic cylinders. It receives current commands from the control system and fine-tunes the flow compensation of one side cylinder in real time to offset uneven flow distribution caused by load deviations and other interferences, further improving the synchronization accuracy of the dual cylinders. The displacement sensor collects the piston rod displacement signal in real time and feeds it back to the control system as the core basis for calculating the synchronization error. During operation, hydraulic oil is filtered by the inlet filter and then enters the solenoid directional valve. When the ladder unfolds, the solenoid on the left side of the solenoid directional valve is energized, and the oil enters the distributor after being regulated by the bidirectional speed control valve. After initial equal distribution, the oil flows to the pipelines on both sides, and after fine-tuning and compensation by the proportional directional valve, it enters the rodless chamber of the drive hydraulic cylinder, pushing the piston rod to extend synchronously and causing the ladder to flip and unfold. When retracting, the solenoid on the right side of the solenoid directional valve is energized, and the oil flows in the opposite direction into the rod chamber of the cylinder, causing the piston rod to retract synchronously. Throughout the process, displacement and pressure sensors provide real-time feedback signals, and the control system dynamically adjusts the flow rate through the proportional directional valve to ensure that the displacement of the drive hydraulic cylinders on both sides is synchronized, preventing the ladder from deflecting or tilting during unfolding.

[0044] Figure 4 The block diagram of the adaptive multi-cylinder load collaborative control algorithm for step stairs is the core logic architecture for the synchronous control of two cylinders in a step stairs. First, the desired trajectory is set as the synchronous displacement error of the two cylinders. The target signal is input to the feedforward model compensation term 1. This module combines the load deviation output by the online parameter estimation based on the model 4. Diversion error Isoparameter estimates Generate feedforward compensation amount This proactively counteracts the interference of known system dynamic characteristics (such as nominal load and inherent damping) on ​​synchronization. The feedforward compensated signal is then superimposed with the outputs of the fast dynamic compensation term 61 (for rapid disturbances such as sudden load changes), the nonlinear feedback term 62 (to suppress nonlinear factors such as proportional valve nonlinearity and cylinder friction), and the linear feedback term 63 (to reduce steady-state synchronization error) to form a comprehensive control quantity. Subsequently, the proportional valve static mapping 2 will... Convert to proportional valve input voltage Driven by a dual-cylinder drive system 3 (corresponding to) Figure 3 (The hydraulic circuit) causes the hydraulic cylinder to shift. , And form a shunt pressure difference Meanwhile, the extended observer 5 receives displacement and differential pressure signals of the dual-cylinder drive system in real time, observes unmodeled dynamics (such as unknown disturbances and model uncertainties), and feeds them back to the fast dynamic compensation term 61 to achieve rapid compensation for sudden disturbances; the online parameter estimation based on the model 4 continuously updates the parameter estimates in conjunction with the system output. This feedback not only optimizes the feedforward model compensation term 1 but also provides parameter support for the extended observer 5. Finally, the error calculation node compares the actual output of the dual cylinders with the expected trajectory to generate a result including displacement error. Differential pressure error Comprehensive error This feedback is further fed back to each feedback item, forming a complete closed loop of "feedforward pre-compensation + multi-feedback closed-loop adjustment + online observation and parameter update", ensuring synchronous displacement of the two cylinders and achieving precise folding and unfolding of the step ladder.

[0045] Figure 5 This is a synchronization error curve diagram of the multi-cylinder load adaptive step ladder deployment process. The maximum, average, and standard values ​​of the synchronization error for the four controllers—PID, DARC, DIARC, and ESO-DIARC—are shown in Table 1 below. Table 1. Synchronization performance indicators of the multi-cylinder load adaptive step ladder deployment process

[0046] Figure 6 This is a synchronization error curve diagram for the step ladder retraction process with multi-cylinder load adaptation. The maximum, average, and standard values ​​of the synchronization error for the four controllers—PID, DARC, DIARC, and ESO-DIARC—are shown in Table 2 below. Table 2 Synchronization performance indicators of the multi-cylinder load adaptive step ladder retraction process

[0047] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit of the invention and the scope of protection of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A multi-cylinder load adaptive staircase expansion cooperative control method, characterized in that, The method is based on a direct / indirect adaptive robust control strategy using an extended state observer, and includes the following steps: Step 1: Establish a dynamic model of the hydraulic cylinder, and design a controller based on the dynamic model of the hydraulic cylinder. The controller includes a feedforward model compensation term, a fast dynamic compensation term, a nonlinear feedback term, and a linear feedback term. Step 2: Input the desired displacement of the hydraulic cylinder and the parameters after model-based online parameter estimation and extended observer processing into the feedforward model compensation term to obtain the feedforward model compensation part. At the same time, input the displacement error and pressure error of the hydraulic cylinder into the fast dynamics compensation term, nonlinear feedback term and linear feedback term in real time, respectively. Step 3: Obtain the flow signal based on the feedforward model compensation term, fast dynamics compensation term, nonlinear feedback term, and linear feedback term. Then, complete the valve control current signal through function mapping of the flow signal and current signal, thereby achieving high-precision control of the hydraulic cylinder displacement and realizing displacement control closed loop.

2. The multi-cylinder load adaptive step-ladder expansion cooperative control method according to claim 1, characterized in that, The specific dynamic model of the hydraulic cylinder is as follows: （1） （2） （3） （4） （5） （6） In the formula, This refers to the pressure in the hydraulic cylinder's inlet chamber. This refers to the pressure in the return oil chamber of the hydraulic cylinder. The effective working area of ​​the hydraulic cylinder piston rod; The total mass of the hydraulic cylinder piston rod and directly connected components; This refers to the displacement of the hydraulic cylinder piston rod. The viscous damping coefficient of the hydraulic cylinder piston rod; It is an external load force; External disturbances and modeling errors; The elastic modulus of hydraulic oil; The internal leakage coefficient of the hydraulic cylinder; This is for the error in the export flow rate; and Given a function; , These are the viscous damping coefficients of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. The valve orifice flow coefficient; Uncertain terms for force modeling; Model uncertainties for the flow; For parameters; and These are the minimum and maximum values ​​of the parameter, respectively. This refers to the total volume of the hydraulic cylinder rod chamber; This refers to the basic volume of the hydraulic cylinder rod cavity; For force loading deviation; ; ; ; ; ; ; ; , , , , , , , , They are respectively , , , , , , , , .

3. The multi-cylinder load adaptive step-ladder expansion cooperative control method according to claim 2, characterized in that, The feedforward model compensation term, fast dynamics compensation term, nonlinear feedback term, and linear feedback term are as follows: Pressure Error Expected Input It consists of the following forms: （7） Flow error expected input Expressed in a similar form: （8） in, For linear feedback gain; This is the compensation term for the pressure error feedforward model; This is a rapid dynamic compensation term for pressure error; This is a linear feedback term for pressure error; This is a nonlinear feedback term for pressure error; For linear feedback gain; Additional compensation terms for the design of the inversion strategy; and These are the weighting coefficients; This is the compensation term for the flow error feedforward model; This is a fast dynamic compensation term for flow error; For the linear feedback term of flow error; This is a nonlinear feedback term for flow error; , It is an arbitrarily small design parameter; This refers to the displacement synchronization error; For pressure difference; For pressure error; These are parameter estimates; and They are respectively: ； ; This is the gain coefficient; and These are the maximum values ​​of the uncertainty terms in force modeling and flow modeling, respectively. This is the computable part of the first derivative of the pressure. Define sliding mode function : （9） Error Dynamics The expression form is: （10） （11） （12） In the formula, For the estimated proportional gain; for The known boundary function; This is the gain coefficient; This is the incalculable part of the first derivative of the pressure; This is the projection function.

4. The multi-cylinder load adaptive step-ladder expansion cooperative control method according to claim 2, characterized in that, Dual-cylinder load deviation in the system and shunting error It is the main disturbance factor affecting feedforward compensation. To achieve fast tracking of it, the following extended state observer is constructed: （13） In the formula, They are respectively as well as Estimated state variables after system expansion; , The observer parameters determine the observer's tracking frequency and observation accuracy.

5. The multi-cylinder load adaptive step-ladder expansion cooperative control method according to claim 4, characterized in that, Observations from the extended state observer , To balance the speed of the extended state observer with the true-value convergence of the online least squares method, data fusion of the two estimates is necessary. When disturbances occur, the extended state observer enables the parameter estimates to quickly approximate the true values. As the tracking error decreases, the online least squares parameter estimator plays a major role, ensuring the convergence of the parameter estimates to the true values. The fused data is then used to... Assign to Participate in feedforward compensation.

6. The multi-cylinder load adaptive step-ladder expansion cooperative control method according to claim 5, characterized in that, After fusion Assign to Specifically: （14） Guaranteed , .

7. A multi-cylinder load adaptive staircase expansion and contraction cooperative control system, said system being used to implement the cooperative control method according to any one of claims 1-6, characterized in that, include: Sensing unit: includes laser displacement sensor and pressure sensor, providing real-time data input for the algorithm; Control unit: includes a PLC controller and a collaborative control algorithm, wherein the PLC controller supports real-time calculation; The actuator includes an electro-hydraulic proportional valve and a double-rod hydraulic cylinder. The electro-hydraulic proportional valve is used to output flow according to a static mapping of "flow rate - current", and the double-rod hydraulic cylinder is used to drive the step ladder to unfold.

8. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 7, characterized in that, The control unit executes the corresponding control process based on the core algorithms of load adaptive parameter estimation, ESO, data fusion and hierarchical collaborative control modules.

9. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 8, characterized in that, The load adaptive parameter estimation module achieves safe and accurate parameter estimation by combining the projective adaptive law with the least squares method. The projective adaptive law is passed through Functional constraints exist Within the specified range, avoid exceeding parameter limits; The least squares method is defined by... , ,through After filtering, a linear regression equation is constructed. Accurately estimate slowly varying parameters; in, This is a parameter derived from the elastic modulus of oil.

10. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 9, characterized in that, The ESO module enables simultaneous observation of state and disturbance, and its observation equations include displacement error observation: ； ； Pressure error observation: ； in , Quickly capture load deviation With shunt error .

11. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 9, characterized in that, The data fusion module combines the accuracy of parameter estimation with the speed of ESO, and the fusion formula is as follows: ； in The load force parameters estimated by the least squares method For ESO-observed load deviation, ensure hour It converges to the true value, balancing accuracy and speed.

12. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 9, characterized in that, The hierarchical collaborative control module adopts displacement-pressure hierarchical control logic to achieve collaborative control; Displacement synchronization layer: target ,definition , Feedforward compensation Rapid compensation Linear feedback Nonlinear robust terms composition; Pressure difference tracking layer target ,definition , Feedforward compensation , Rapid compensation Linear feedback Nonlinear robust terms composition.

13. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 9, characterized in that, The execution output will Convert to proportional valve control current This drives the hydraulic cylinder to move.

14. The multi-cylinder load adaptive staircase expansion and contraction cooperative control system according to claim 9, characterized in that, The control process specifically includes: Step 1, Initialization: Power on and initialize algorithm parameters and sensor zero point; Step 2, Data Acquisition: The sensing unit acquires data in real time. / , / The data is transmitted to the control unit. Step 3, Error Calculation: Calculate , and rate of change , ; Step 4, Parameter and Disturbance Estimation: Output of the Load Adaptive Parameter Estimation Module ESO output / Data fusion module output ; Step 5, Control Variable Calculation: Calculated by the hierarchical collaborative control module. and convert to ; Step 6, Execution and Feedback: The execution unit drives the hydraulic cylinder and repeats steps 2-5 until the folding is complete.

Images