Pure electric loader hinged steering system and multi-source disturbance suppression method thereof

Abstract

The invention discloses a hinge steering system of a pure electric loader and a multi-source disturbance suppression method of the hinge steering system. Comprising a frame assembly, a hinge mechanism, a motor electromagnetic quantity estimation unit, a motor displacement and speed measurement unit, a hinge angle measurement unit, a steering angle acquisition unit, a vehicle motion state measurement unit, a load identification and estimation unit, an electric hinge execution unit, a linear motor controller, a whole vehicle domain controller, a vehicle-mounted communication network and a power supply module. The linear motor is used for directly outputting thrust to achieve hinged steering, traditional hydraulic and mechanical transmission links are eliminated, the system structure is more compact, meanwhile, the high response speed and the high steering precision are achieved, and therefore the operation stability and the control reliability of the whole machine are improved.

Description

Technical Field

[0001] This invention relates to the technical field of loaders, and more particularly to an articulated steering system for a pure electric loader and a method for suppressing multi-source disturbances thereon. Background Technology

[0002] The electrification transformation of construction machinery continues to advance, and the electrification of the entire machine has become an important trend in the development of loader technology. Electrified drive systems can significantly reduce energy consumption and carbon emissions, and possess advantages such as high response and high efficiency. Therefore, how to achieve the electrification of key actuators is an important research direction in the current construction machinery field.

[0003] Existing publicly available solutions mostly employ hydraulically driven articulated steering systems. Some research attempts to replace hydraulic cylinders with electric cylinders and servo motors, achieving linear extension and retraction by driving ball screws or planetary ball screws with rotary motors. For example, Chinese invention patent applications CN202410895265.6, entitled "A pure electric loader and its electric cylinder articulated steering system control method"; CN202421577243.7, entitled "A loader and its electric steering system"; and CN202510696627.3, entitled "An electric drive system, drive method, and electric loader." While these technical solutions reduce energy loss and maintenance requirements of hydraulic systems to some extent, they still have significant limitations in terms of transmission efficiency, dynamic response performance, and long-term reliability.

[0004] In contrast, using a linear motor to directly output thrust for articulated steering eliminates intermediate mechanical transmission links and offers significant advantages such as high response, high precision, and compact structure. However, the electromagnetic characteristics and nonlinear thrust characteristics of the linear motor drive system, as well as the dynamic fluctuations caused by load changes under complex operating conditions of the loader, pose new challenges to steering control, necessitating specialized control strategies for compensation and optimization.

[0005] Current research faces two key challenges. First, linear motors are inevitably affected by internal disturbances during dynamic thrust output, such as end effect forces, electromagnetic saturation, and flux linkage changes caused by temperature rise. These factors cause deviations between the actual thrust and the theoretical electromagnetic force, resulting in periodic fluctuations or nonlinear distortions in the thrust. If the control system cannot identify and compensate for these internal disturbances in real time, it will lead to jitter, overshoot, or steady-state errors in the steering response, thereby reducing the accuracy of articulation angle control.

[0006] Secondly, loaders operate in diverse environments. Their front and rear frames are affected by load distribution, loading resistance, and uneven terrain, exhibiting significantly different equivalent moments of inertia, normal loads, and lateral force characteristics under different conditions (fully loaded, half-loaded, unloaded, turning while loading, bumpy roads, etc.). These external disturbances directly affect the thrust requirements of the linear motor and the dynamic characteristics of the system. If fixed parameters or traditional linear models are used for control, it is often impossible to balance stability and consistency under different operating conditions, which can easily lead to sluggish steering response, decreased accuracy, or even oscillations.

[0007] Therefore, it is necessary to propose an articulated steering system for pure electric loaders and its multi-source disturbance suppression method. By constructing an online internal disturbance compensation mechanism and an adaptive adjustment strategy for external disturbances, dynamic correction of the linear motor thrust output and precise control of the steering response process can be achieved, thereby ensuring the steering accuracy, dynamic consistency and system stability of the loader under various operating conditions. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0009] In view of the problems existing in the articulated steering system of pure electric loaders and its multi-source disturbance suppression methods, the present invention is proposed.

[0010] Therefore, the purpose of this invention is to provide a pure electric loader articulated steering system and its multi-source disturbance suppression method. It uses a linear motor to directly output thrust to achieve articulated steering, eliminating traditional hydraulic and mechanical transmission links, making the system structure more compact, and at the same time having high response speed and high steering accuracy, thereby improving the overall machine's handling stability and control reliability.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a pure electric loader articulated steering system, comprising: a frame assembly, an articulation mechanism, a motor electromagnetic quantity estimation unit, a motor displacement and speed measurement unit, an articulation angle measurement unit, a steering angle acquisition unit, a vehicle motion state measurement unit, a load identification and estimation unit, an electric articulation execution unit, a linear motor controller, a vehicle domain controller, an on-board communication network, and a power supply module.

[0012] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the frame assembly includes a front frame and a rear frame of the loader; the articulation mechanism is located at the connection between the front and rear frames and is used to realize the relative rotation of the front and rear frames.

[0013] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the motor electromagnetic quantity estimation unit collects the current and bus voltage information of the linear motor and estimates the motor output thrust and electromagnetic power in real time; the motor displacement and speed measurement unit is used to measure the motor displacement and speed and transmit them to the linear motor controller in real time.

[0014] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the articulation angle measuring unit is located on one side of the articulation mechanism and is used to measure the relative turning angle and angular velocity of the front and rear frames. It includes an angle sensor, a first link and a second link. The angle sensor is installed at one end of the articulation mechanism, the first link is hinged to the other end of the articulation mechanism, and the second link is hinged to the first link.

[0015] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the steering angle acquisition unit is used to acquire the driver's steering intention signal, including the desired steering angle and steering angular velocity, and transmit the signal to the linear motor controller as a control input; the vehicle motion state measurement unit includes an inertial measurement unit, a vehicle speed sensor and a yaw rate measurement device, used to acquire vehicle attitude and motion state information, and provide it to the linear motor controller for coordinated control together with the output information of the load identification unit.

[0016] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the load identification and estimation unit estimates the front and rear axle normal loads and tire equivalent stiffness in real time based on the articulation angle, lifting height, bucket load, and acceleration response, and is used to correct the controller reference model and constraints; the electric articulation execution unit includes a left linear motor and a right linear motor, which work together to achieve articulation angle control; the linear motor controller is connected to the vehicle domain controller through an on-board communication network to receive measurement signals and operating condition information, generate current commands and articulation control commands, and output the compensated control quantity to the electric articulation execution unit to achieve closed-loop control of the linear motor articulated steering.

[0017] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the vehicle-mounted communication network supports high-speed data exchange and time synchronization, and supports real-time transmission of control commands and feedback data to ensure the coordinated operation of each control module and measurement unit.

[0018] As a preferred embodiment of the articulated steering system for a pure electric loader according to the present invention, the power supply module provides DC power to the linear motor controller, the electric articulated actuator and other electronic modules to ensure the stable operation of the system under different working conditions.

[0019] A method for suppressing multi-source disturbances in the articulated steering system of a pure electric loader includes the following steps: 1) Collect current and speed data of linear motors, perform appropriate noise reduction, anti-aliasing and normalization processing to obtain effective measurement data that can be used for state inference; construct an augmented state-space model for online estimation, and incorporate internal disturbances such as thrust fluctuations as extended states into a unified framework; design an observer based on the state-space model to observe and identify internal disturbances in real time; calculate the corresponding compensation current based on the estimated disturbance, and inject the compensation signal into the current loop command to achieve dynamic suppression and compensation of internal disturbances; 2) Real-time identification and classification of the external working conditions of the loader are performed in conjunction with the vehicle's motion state; an adaptive controller is constructed based on the identification results, and disturbance characteristics are added to the controller's state vector to update the control gain online; the control output is processed in conjunction with robust limiting and damping injection mechanisms to suppress transient impacts caused by external disturbances, thereby maintaining the stability and consistency of the linear motor articulated steering control under varying working conditions. 3) Based on the internal disturbance compensation signal generated in step 1) and the external disturbance adaptive control signal generated in step 2), the final articulation control command is formed according to the dynamic model of the linear motor articulated steering system; based on the real-time vehicle status, the control command is multi-mode allocated and optimized; safety constraints and predictive protection are implemented for the articulation angle control command to achieve stable, high-precision and safe operation of the linear motor articulated steering under multiple working conditions and multiple disturbance conditions.

[0020] The beneficial effects of this invention are: 1. The present invention provides a pure electric loader articulated steering system, which uses a linear motor to directly output thrust to achieve articulated steering, eliminating the traditional hydraulic and mechanical transmission links, making the system structure more compact, and having high response speed and high steering accuracy, thereby improving the overall machine's handling stability and control reliability.

[0021] 2. This invention achieves online observation and compensation for internal disturbances such as motor thrust fluctuations by real-time acquisition and augmented state-space modeling of linear motor current and speed signals, and by designing a Kalman filter observer. This effectively suppresses control errors caused by the linear motor's own end effect forces and dynamic nonlinearity, improving the response speed and control accuracy of articulated steering.

[0022] 3. This invention combines real-time identification and classification of vehicle motion status, load, and operating conditions, and adjusts key control parameters online through an adaptive controller. It also incorporates amplitude limiting and damping injection mechanisms to suppress transient impacts caused by external disturbances. Under different load, speed, and adhesion conditions, it can maintain the stability, consistency, and operational safety of articulated steering. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the system structure of the pure electric loader articulated steering system and its multi-source disturbance suppression method of the present invention.

[0024] Figure 2 This is a schematic diagram illustrating the principle and structure of the articulated steering system for a pure electric loader and its multi-source disturbance suppression method according to the present invention.

[0025] Figure 3 This is a schematic diagram illustrating the principle of the articulated steering system for a pure electric loader and its multi-source disturbance suppression method according to the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0030] Reference Figures 1-3A pure electric loader articulated steering system is provided, including: a frame assembly, an articulation mechanism 3, a motor electromagnetic quantity estimation unit 5, a motor displacement and speed measurement unit 6, an articulation angle measurement unit, a steering angle acquisition unit 9, a vehicle motion state measurement unit 11, a load identification and estimation unit 10, an electric articulation execution unit, a linear motor controller 2, a vehicle domain controller 16, an on-board communication network, and a power supply module 7.

[0031] The frame assembly includes a loader front frame 1 and a loader rear frame 8; the articulation mechanism 3 is located at the connection between the front and rear frames and is used to realize the relative rotation of the front and rear frames; the motor electromagnetic quantity estimation unit 5 collects the current and bus voltage information of the linear motor and estimates the motor output thrust and electromagnetic power in real time; the motor displacement and speed measurement unit is used to measure the motor displacement and speed and transmit them to the linear motor controller in real time.

[0032] The hinge angle measuring unit is located on one side of the hinge mechanism 3 and is used to measure the relative rotation angle and angular velocity of the front and rear frames. It includes an angle sensor 13, a first link 15, and a second link 14. The angle sensor 13 is installed at one end of the hinge mechanism 3, the first link 15 is hinged to the other end of the hinge mechanism 3, and the second link 14 is hinged to the first link 15. The steering angle acquisition unit 9 is used to acquire the driver's steering intention signal, including the desired steering angle and steering angular velocity, and transmit the signal to the linear motor controller as a control input; the vehicle motion state measurement unit 11 includes an inertial measurement unit, a vehicle speed sensor and a yaw rate measurement device, used to acquire vehicle attitude and motion state information, and together with the output information of the load identification unit, it is provided to the linear motor controller 2 for coordinated control.

[0033] The load identification and estimation unit 10 estimates the front and rear axle normal loads and tire equivalent stiffness in real time based on the articulation angle, lifting height, bucket load, and acceleration response, which is used to correct the controller reference model and constraints. The electric articulation actuator includes a left linear motor 4 and a right linear motor 12. The two linear motors work together to achieve articulation angle control. The linear motor controller 2 is connected to the vehicle domain controller through the vehicle communication network to receive measurement signals and operating condition information, generate current commands and articulation control commands, and output the compensated control quantity to the electric articulation actuator to achieve closed-loop control of linear motor articulated steering.

[0034] Furthermore, the vehicle-mounted communication network supports high-speed data exchange and time synchronization, and supports real-time transmission of control commands and feedback data to ensure the coordinated operation of various control modules and measurement units.

[0035] Power supply module 7 provides DC power to the linear motor controller 2, electric articulated actuator and other electronic modules to ensure stable operation of the system under different working conditions.

[0036] Specifically, a method for suppressing multi-source disturbances in the articulated steering system of a pure electric loader includes the following steps: 1) Collect current and speed data of linear motors, perform appropriate noise reduction, anti-aliasing and normalization processing to obtain effective measurement data that can be used for state inference; construct an augmented state-space model for online estimation, and incorporate internal disturbances such as thrust fluctuations as extended states into a unified framework; design an observer based on the state-space model to observe and identify internal disturbances in real time; calculate the corresponding compensation current based on the estimated disturbance, and inject the compensation signal into the current loop command to achieve dynamic suppression and compensation of internal disturbances; 2) Real-time identification and classification of the external working conditions of the loader are performed in conjunction with the vehicle's motion state; an adaptive controller is constructed based on the identification results, and disturbance characteristics are added to the controller's state vector to update the control gain online; the control output is processed in conjunction with robust limiting and damping injection mechanisms to suppress transient impacts caused by external disturbances, thereby maintaining the stability and consistency of the linear motor articulated steering control under varying working conditions. 3) Based on the internal disturbance compensation signal generated in step 1) and the external disturbance adaptive control signal generated in step 2), the final articulation control command is formed according to the dynamic model of the linear motor articulated steering system; based on the real-time vehicle status, the control command is multi-mode allocated and optimized; safety constraints and predictive protection are implemented for the articulation angle control command to achieve stable, high-precision and safe operation of the linear motor articulated steering under multiple working conditions and multiple disturbance conditions.

[0037] Furthermore, step 1) specifically includes: 1.1) Data Acquisition and Preprocessing: Linear motor data is acquired in real time through the motor electromagnetic quantity estimation unit and the motor displacement and speed measurement unit, and transmitted to the linear motor controller for real-time processing via the vehicle communication network. The acquired raw signals are represented as follows: ; in, This represents the displacement of the motor's moving part. This is the equivalent value of the q-axis current of the motor, reflecting the electromagnetic thrust input; The instantaneous displacement speed of the mover reflects the mechanical output state. and These represent the thrust fluctuation and its rate of change of the linear motor.

[0038] First of all An anti-aliasing low-pass filter is applied to suppress high-frequency noise. The filter transfer function is: ; in, This indicates the cutoff angular frequency of the low-pass filter. This represents the cutoff frequency of the low-pass filter, and s is the Laplace operator.

[0039] Signal received: ; Subsequently Perform wavelet soft thresholding denoising: ; in, The noise threshold is usually selected based on the statistical characteristics of the noise or adaptively estimated.

[0040] Finally, normalization is performed using the Min–Max normalization form: ; The final preprocessed signal is obtained:

[0041] 1.2) Constructing the augmented state-space model: Based on the preprocessed data in 1.1), and according to the dynamic characteristics of the linear motor articulated actuator, the mover position, speed, internal disturbances, and their rates of change are selected as system state variables to construct the augmented state vector: ; in, For the position of the mover, The linear velocity of the moving part. and These represent the thrust fluctuation and its rate of change of the linear motor.

[0042] The system input is electromagnetic thrust Fe, which can be used as q-axis current. Equivalent representation:

[0043] The dynamic equations of a linear motor can be written as follows:

[0044] in, For equivalent motion mass, Electromagnetic thrust, For thrust fluctuation, For load thrust, For other disturbance forces.

[0045] Based on the dynamic equations and the settings of system state and input variables, the state-space expression of the linear motor can be written as: ; in: ; ;

[0046] The system output consists of measurable variables:

[0047] Written in matrix form:

[0048] in:

[0049] In order to apply the state-space expression of a linear motor to a digital control system, the mathematical model of the motor system needs to be discretized:

[0050] in, , , , Sampling time.

[0051] 1.3) Online Observation and Identification: Based on the discretized augmented state-space model constructed in 1.2), an internal perturbation observer based on a Kalman filter is designed. This observer utilizes measured displacement, velocity, and current information to achieve optimal linear unbiased estimation of the perturbation, providing real-time perturbation quantities for subsequent compensation current calculations.

[0052] Predict the state at the next moment:

[0053] Calculate the predicted covariance:

[0054] Where Q is the process noise covariance, reflecting the randomness of disturbance changes and model uncertainty.

[0055] The state estimate is corrected based on the deviation between the actual output and the predicted output:

[0056] in, R is the Kalman gain, and R is the measurement noise covariance, which is determined by the sensor accuracy and sampling link noise.

[0057] The corrected state is obtained:

[0058] And update the covariance:

[0059] Where I represents the identity matrix with the same dimensions as the covariance matrix. Finally, the state vector output by the filter is:

[0060] in, For estimating the displacement of the mover, For motioner velocity estimation, and These are estimates of thrust fluctuation and thrust fluctuation rate of change, respectively.

[0061] Real-time estimation of internal disturbances is achieved by using a Kalman filter observer and current measurement information and a prediction model.

[0062] 1.4) Compensation current calculation and injection: Based on 1.3), the real-time estimate of the disturbance is obtained. With the rate of change of disturbance An equivalent compensation current is generated based on the disturbance characteristics and injected into the current loop to suppress internal thrust fluctuations.

[0063] The perturbation thrust estimated by Kalman filtering Converted to equivalent compensation current:

[0064] in, This is the thrust coefficient, obtained through calibration.

[0065] To compensate for the rapid changes in the disturbance, the rate of change of the disturbance is... As a feedforward effect, it is added to the compensation model:

[0066] in, The perturbation rate of change compensation gain is used to improve dynamic response and suppress transient shocks caused by abrupt perturbation changes in advance.

[0067] The final compensation current consists of two parts:

[0068] in, This is the compensation current for internal disturbances.

[0069] By injecting and compensating current, the effects of disturbances can be instantly counteracted when they occur, thereby significantly improving the stability of the motor's thrust output.

[0070] Furthermore, step 2) specifically includes: 2.1) Real-time vehicle operating condition identification and classification: Combining the disturbance observations obtained in step 1), and the vehicle motion state variables, a vehicle operating condition feature vector is constructed:

[0071] in, For the longitudinal speed of the vehicle, For the longitudinal acceleration of the vehicle, For the disturbance estimator, For bucket load capacity, To raise the height.

[0072] To achieve automatic classification of different working conditions, a working condition severity index function is defined:

[0073] Among them, w1, w2, w3, and w4 are empirical weighting factors used to measure the importance of acceleration excitation, disturbance intensity, and steering dynamics.

[0074] Based on indicators Perform operating condition classification:

[0075] in, and The operating condition threshold was obtained through experimental calibration.

[0076] 2.2) Adaptive Controller Construction and Online Parameter Update: Based on the operating condition severity index function obtained in 2.1) and the corresponding operating condition levels A reference model is constructed to address the articulated dynamic behavior of vehicles in ideal environments (weak external disturbances and stable load changes):

[0077] in, For reference hinge angle state, The driver's steering intention (i.e., the desired hinge angle). and It is a 2×2 Herwitz matrix, determined by calibration experiments or simulations.

[0078] This model is used to provide the desired dynamic trajectory, which drives adaptive parameter adjustments.

[0079] The internal disturbance estimate obtained in step 1) External operating condition indicators Incorporate them into the reference model to form an enhanced controlled object model:

[0080] in, This represents the actual hinge angle. This is the equivalent control quantity for the current loop of the linear motor. and This is the perturbation channel gain matrix.

[0081] The adaptive control law adopts the MRAC structure:

[0082] in, The adaptive parameter vector for the state feedback gain. Both are feedforward gain, and are adjusted online according to changes in operating conditions.

[0083] Define tracking error:

[0084] Its dynamics satisfy:

[0085] in, and For ideal gain.

[0086] Finally, operating condition weights are introduced. To accelerate parameter tuning under strong disturbances. The online updates of the state feedback gain and feedforward gain are as follows:

[0087] in, and For adaptive gain adjustment, P is a positive definite matrix.

[0088] When the vehicle is under strong disturbance or heavy load conditions, the adaptive law automatically increases the parameter tuning speed to enable the system to quickly compensate for insufficient gain; under light load and stable conditions, the parameter tuning speed is reduced to avoid unnecessary parameter fluctuations and improve system stability.

[0089] 2.3) Robust Limiting and Damping Injection: To avoid overshoot of control commands caused by high load impacts, sudden accelerations, or sharp turns, the output control quantity of the adaptive controller in step 2.2) is adjusted. Robustness measures are implemented to ensure a smooth response of the linear motor articulated actuator.

[0090] To avoid control command spikes caused by sudden large disturbances, the control quantity is limited to a safe dynamic range:

[0091] in, and Dynamic adjustments are made based on vehicle load level, lifting height, and yaw rate.

[0092] Amplitude limiting is achieved using a smooth saturation function:

[0093] To suppress transient oscillations of the articulated angular velocity under operational impacts, uneven road surfaces, or high inertia loads, equivalent viscous damping compensation is introduced:

[0094] in, This is the actual hinge angular velocity. This is the damping coefficient, which is adjusted in real time according to the load level, lifting height, and acceleration status.

[0095] Furthermore, step 3) specifically includes: 3.1) Generate articulated control commands: Based on the external disturbance adaptive compensation amount obtained in step 2), and combined with the internal disturbance compensation amount in step 1), the input value of the current loop controller is obtained. :

[0096] in, This is the internal disturbance compensation current. External disturbance compensation current for amplitude limiting processing. Inject compensation current into the damping.

[0097] The displacement-velocity-current closed-loop control of the left and right linear motors is achieved through a linear motor controller, and the final articulation angle control command is generated based on the dynamic model of the linear motor articulated steering system. :

[0098] Where R and r are the distances from the articulation point to the connection points of the front and rear vehicle bodies, respectively, and L1L2 and R1R2 represent the real-time working lengths of the linear motors on the left and right sides, respectively. This is the final articulation angle control command for the vehicle. and These represent the displacements of the linear motors on the left and right sides, respectively, which are measured in real time by the motor displacement and speed measurement unit. The initial installation angles are for the linear motors on the left and right sides.

[0099] 3.2) Multi-mode allocation and control command optimization: To balance steering response characteristics and system robustness under different operating scenarios, the system presets three typical operating modes:

[0100] in, For pattern numbering, The mode is determined by the vehicle's real-time status. Mode A is used when there is low speed, low load, and small angle change; Mode B is used for normal driving; and Mode C is used when there is high load, strong disturbance, or high-frequency command.

[0101] Determine a set of fixed weights based on the pattern:

[0102] in, For the internal disturbance compensation term weight, Weights of the adaptive compensation term for external disturbances. The weight of the damping injection term.

[0103] The weights satisfy:

[0104] According to the current mode The three current sub-terms in step 3.1) are weighted and combined:

[0105] in, The original candidate instructions after multi-mode allocation.

[0106] Fine-grained mode assigns more weight to Fine-grained control; robust mode allocates more weight to To improve stability; the standard mode is a compromise among the three.

[0107] To avoid current command jumps caused by mode switching, disturbances, or noise, Real-time instruction smoothing is performed using a first-order low-pass filter:

[0108] in, For smoothing coefficients, This is the smoothed current command output.

[0109] 3.3) Safety Constraints and Predictive Protection: Based on the final hinge angle control command obtained in step 3.1). Predictive constraints are implemented to reduce control variables in advance and prevent out-of-bounds occurrences in future sampling periods.

[0110] Based on the current hinge angle and hinge angular velocity Predict the hinge angle for the next N sampling periods:

[0111] in, To control the sampling period, the hinge angle is the predicted k-th future sampling period.

[0112] If the predicted hinge angle may exceed the safety limits (lower and lower limits). and Command to adjust hinge angle using weighted cumulative method:

[0113] in, The adjustment coefficient can be adaptively set according to load, vehicle speed, and operating mode. The weighting is based on time decay; the weight of predictions for the more distant the future is, the smaller the weight. This is the revised safety hinge angle command.

[0114] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A pure electric loader articulated steering system, characterized in that, The application relates to a vehicle frame assembly, a hinge mechanism (3), a motor electromagnetic quantity estimation unit (5), a motor displacement and speed measurement unit (6), a hinge angle measurement unit, a steering angle acquisition unit (9), a vehicle motion state measurement unit (11), a load identification and estimation unit (10), an electric hinge execution unit, a linear motor controller (2), a vehicle domain controller (16), a vehicle-mounted communication network and a power supply module (7). The vehicle frame assembly comprises a loader front frame (1) and a loader rear frame (8); the hinge mechanism (3) is arranged at a connecting position of the front frame and the rear frame and is used for realizing relative rotation of the front frame and the rear frame.

2. The pure electric loader articulated steering system of claim 1, wherein: The motor electromagnetic quantity estimation unit (5) acquires current and bus voltage information of the linear motor and realizes real-time estimation of motor output thrust and electromagnetic power; the motor displacement and speed measurement unit is used for measuring motor displacement and speed and transmitting the same to the linear motor controller in real time.

3. The pure electric loader articulated steering system of claim 2, wherein: The hinge angle measurement unit is arranged at one side of the hinge mechanism (3) and is used for measuring relative rotation angle and angular velocity of the front frame and the rear frame and comprises a rotation angle sensor (13), a first connecting rod (15) and a second connecting rod (14), wherein the rotation angle sensor (13) is arranged at one end of the hinge mechanism (3), the first connecting rod (15) is hingedly connected to the other end of the hinge mechanism (3), and the second connecting rod (14) is hingedly connected to the first connecting rod (15).

4. The pure electric loader articulated steering system of claim 3, wherein: The steering angle acquisition unit (9) is used for acquiring steering intention signals of a driver, including expected rotation angle and steering angular velocity, and transmitting the signals to the linear motor controller as control input; the vehicle motion state measurement unit (11) comprises an inertial measurement unit, a vehicle speed sensor and a yaw rate measurement device and is used for acquiring vehicle posture and motion state information and providing the information to the linear motor controller (2) together with output information of the load identification unit for collaborative control.

5. The pure electric loader articulated steering system of claim 1, wherein: The load identification and estimation unit (10) realizes real-time estimation of front and rear axle normal loads and tire equivalent stiffness based on hinge angle, lifting height, load weight and acceleration response and is used for correcting a controller reference model and constraint conditions; the electric hinge execution unit comprises a left linear motor (4) and a right linear motor (12), the two linear motors work collaboratively to realize hinge angle control; the linear motor controller (2) is connected with the vehicle domain controller through the vehicle-mounted communication network, is used for receiving measurement signals and working condition information, generating current instructions and hinge control instructions and outputting compensated control quantities to the electric hinge execution unit to realize closed-loop control of linear motor hinge steering.

6. The pure electric loader articulated steering system of claim 5, wherein: The vehicle-mounted communication network supports high-speed data exchange and time synchronization, supports real-time transmission of control instructions and feedback data and is used for guaranteeing collaborative operation of various control modules and measurement units.

7. The pure electric loader articulated steering system of claim 1, wherein: The power supply module (7) provides DC power for the linear motor controller (2), the electric hinge execution unit and other electronic modules and guarantees stable operation of the system under different working conditions.

8. The pure electric loader articulated steering system of claim 1, wherein: The application further discloses a control method of the vehicle frame assembly.

9. A method of multi-source disturbance rejection for a pure electric loader articulated steering system, the method comprising: ​ 1) Collecting linear motor current and speed data, making appropriate denoising, anti-aliasing and normalization processing to obtain effective measurement data for state inference; Constructing an augmented state space model for online estimation, taking internal disturbances such as thrust fluctuations into a unified framework as extended states; Designing an observer based on the state space model to observe and identify internal disturbance quantities in real time; Calculate the corresponding compensation current according to the estimated disturbance quantity, and inject the compensation signal into the current loop command to realize dynamic suppression and compensation of internal disturbances; 2) Real-time identification and classification of external working conditions of loaders combined with vehicle motion state; According to the identification results, construct an adaptive controller and add disturbance characteristics to the controller state vector to update the control gain online; Combine robust limiting and damping injection mechanism to suppress the control output, suppress the transient impact caused by external disturbances, and maintain the stability and consistency of the linear motor articulated steering control under varying conditions; 3) Based on the internal disturbance compensation signal generated in step 1) and the external disturbance adaptive control signal generated in step 2), form the final articulated control command according to the linear motor articulated steering system dynamics model; Based on the real-time state of the vehicle, the control command is distributed and optimized in multiple modes; Implement safety constraints and predictive protection on the articulated angle control command to realize stable, high-precision and safe operation of the linear motor articulated steering under multiple working conditions and multiple disturbances.

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