An electric suspension device for working tools and a nonlinear control method thereof

Abstract

The present invention discloses an electric suspension device for a work tool and a nonlinear control method. The electric suspension device includes a base, a suspension bracket, a control unit, a parallel linkage mechanism, a connector provided on the parallel linkage mechanism, two electric push rods, a linear sensor for measuring the telescopic length of each electric push rod, and an angle detection mechanism for measuring the swing angle of the parallel linkage mechanism. One end of the parallel linkage mechanism is hinged to the base, and the other end is hinged to the suspension bracket. One end of the electric push rod is connected to the base, and the other end is connected to the connector. The base is fixedly connected to a new energy electric tractor, and the suspension bracket is connected to the work tool. The electric push rod, linear sensor, and angle detection mechanism are all electrically connected to the control unit. The electric suspension device adopts an electric drive mode, which can achieve precise adjustment of the height of the work tool, with higher control accuracy and higher energy efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery, and in particular to an electric suspension device for an operating tool and a nonlinear control method thereof. Background Art

[0002] The suspension connects the tractor to the work implement, and its structure directly impacts the tractor's operating efficiency. Traditional agricultural machinery uses a hydraulically driven suspension mechanism, which requires the engine to transmit power to the hydraulic mechanism. This approach also suffers from limited control accuracy, making precise adjustment of the implement height impossible and energy inefficiency low. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned problems and provide an electric suspension device for a work tool. The electric suspension device adopts an electric drive mode, which can accurately adjust the height of the work tool, with higher control accuracy and higher energy efficiency.

[0004] Another object of the present invention is to provide a nonlinear control method.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An electric suspension device for an operating tool comprises a base, a suspension frame, a control unit, a parallel linkage mechanism arranged between the base and the suspension frame, a connecting piece arranged on the parallel linkage mechanism, two electric push rods arranged between the base and the connecting piece, a linear sensor for measuring the telescopic length of each electric push rod, and an angle detection mechanism for measuring the swing angle of the parallel linkage mechanism; wherein, one end of the parallel linkage mechanism is hinged to the base, and the other end of the parallel linkage mechanism is hinged to the suspension frame; one end of the electric push rod is connected to the base, and the other end of the electric push rod is connected to the connecting piece; the base is fixedly connected to a new energy electric tractor, and the suspension frame is connected to the operating tool; the electric push rod, the linear sensor, and the angle detection mechanism are all electrically connected to the control unit.

[0007] The working principle of the above electric suspension device is:

[0008] During operation, the two electric push rods achieve precise synchronous telescopic movement through the linear sensor, thereby driving the parallel linkage mechanism to swing, thereby driving the lifting and lowering of the suspension frame, and the suspension frame is connected to the work tool, thereby realizing the lifting and lowering of the work tool; the angle detection mechanism can accurately detect the swing angle of the parallel linkage mechanism, thereby detecting the current height of the work tool; the control unit can control the extension and retraction of the electric push rod according to the information feedback from the linear sensor and the angle detection mechanism, lowering the work tool to a specific angle during operation, and lifting the work tool when turning in the field to avoid collision between the work tool and the field ridge, which is conducive to the intelligentization of paddy field operations.

[0009] In a preferred embodiment of the present invention, the linear sensor is a pull-wire displacement linear sensor, with two pull-wire displacement linear sensors provided in a one-to-one correspondence with the two electric push rods. The pull-wire displacement linear sensors are fixed to the electric push rods, and the measuring ends of the pull-wire displacement linear sensors are connected to the telescopic ends of the electric push rods. By providing two pull-wire displacement linear sensors, the two electric push rods can be detected separately, and the telescopic length of the electric push rods can be measured in real time.

[0010] Furthermore, the cable-drawn linear displacement sensor has a measurement range of 0 to 1000 mm and is IP68 waterproof and dustproof. It communicates with the control unit using the CANopen communication protocol. A threshold is set for the detection length interval, and the cable-drawn linear displacement sensor determines whether the two electric actuators are operating synchronously within the set operating range. If so, the electric actuators operate according to the originally set task; if not, they operate according to the synchronization algorithm.

[0011] Preferably, the parallel linkage mechanism includes two sets of parallel linkage assemblies, each set of parallel linkage assemblies includes two parallel linkages arranged vertically and parallel to each other, one end of each linkage being hinged to the base, and the other end of each linkage being hinged to the suspension frame; the connecting member is disposed on the linkage. In the above structure, the parallel linkage mechanism, the base, and the suspension frame constitute a parallel four-bar linkage mechanism. The connecting member is used to optimize the load-bearing capacity of the electric push rod. The electric push rod is hinged to the connecting member, so that the movement of the electric push rod can drive the movement of the connecting member. Since the connecting member is located between the base and the suspension frame, when the connecting member moves, the suspension frame also moves, driving the movement of the work tool.

[0012] Furthermore, the position of the connecting part is selected through multiple tests. The connecting part can optimize the load force distribution of the entire electric suspension device, so that the electric push rod can reach the maximum load-bearing capacity within the tolerable rated range. The final test determined that when the distance between the connecting part and the base is 300mm, the load-bearing performance of the electric push rod reaches the best, and the stability of the structure reaches the best state, effectively avoiding the occurrence of dangerous accidents such as deformation of structural parts or jamming of the electric push rod under large loads.

[0013] Preferably, the angle detection mechanism includes an angle sensor disposed on the base and a transmission assembly disposed between the angle sensor and the connecting rod, wherein the angle sensor is connected to the control unit; the transmission assembly includes a first rotating rod and a second rotating rod, wherein one end of the first rotating rod is fixedly connected to the axis of the angle sensor; the other end of the first rotating rod is connected to one end of the second rotating rod, and the other end of the second rotating rod is connected to the connecting rod. By configuring the above mechanism, as the connecting rod moves, the second rotating rod is driven to move, which in turn drives the first rotating rod to rotate, causing the axis of the angle sensor to rotate, thereby detecting the movement of the parallel linkage mechanism and calculating the current angle of the parallel linkage mechanism.

[0014] Furthermore, the angle sensor has an input voltage of 5V and an output voltage Hall effect of 0-5V, corresponding to an angle detection range of 360°. A threshold is set for the detection angle, and the angle sensor is used to determine whether the parallel linkage mechanism is operating within the set operating range. If so, the electric push rod does not operate; if not, the electric push rod operates according to the movement signal.

[0015] A nonlinear control method is applied to the electric suspension device, and the nonlinear control method comprises the following steps:

[0016] (1) Before the electric suspension device starts operating for the first time, it is necessary to calibrate the two electric push rods and the two linear sensors. The control unit stores the calibration values ​​obtained by the calibration operation in the internal storage space.

[0017] (2) The electric suspension device starts to operate normally:

[0018] (2.1) The control unit reads the calibration value from the internal storage space; the control unit pushes the electric push rod to the reference position determined during calibration based on the calibration value, and checks the output value of the linear sensor;

[0019] (2.2) Detecting the real-time position of the electric push rods, reading the output values ​​of the two linear sensors through the control unit, and detecting whether there is a position deviation between the two electric push rods;

[0020] (2.3) If there is a position deviation between the two electric push rods, the direction operation strategy of each electric push rod is determined according to the positive or negative value of the position error;

[0021] (2.4) Based on the direction operation strategy, the dual electric push rod synchronization algorithm is used to determine the specific speed of the two electric push rods;

[0022] (2.5) Check whether the two electric linear actuators are in synchronization after adjustment using the dual electric linear actuator synchronization algorithm.

[0023] Preferably, in step (1), the specific process of the calibration operation is as follows: a reference position needs to be determined as the initial synchronization state of the two electric push rods; the reference position is a fixed position value; after the electric push rods are pushed to the reference position, the two linear sensors are calibrated, and the output values ​​of the two linear sensors at this time are the calibration values, and the control unit stores the calibration values ​​as reference values ​​of the linear sensors. The purpose is to ensure that the two electric push rods maintain a synchronization state when they are in the initial position, which serves as the reference value of the linear sensors, so as to ensure the stability and accuracy of the output values ​​of the linear sensors later.

[0024] Preferably, in step (1), the position where the electric push rod has the shortest telescopic length is taken as the reference position. This is for the purpose of facilitating rapid calibration and making the reference more accurate.

[0025] Preferably, in step (2.1), the specific steps of checking the output value of the linear sensor are: checking whether the output value of the linear sensor is correct; if correct, entering the initialization success state; if wrong, entering the initialization failure state.

[0026] Preferably, in step (2.3), the specific steps of determining the directional operation strategy of each electric push rod according to the positive and negative values ​​of the position error are: if the position of the left electric push rod is ahead of the position of the right electric push rod, the extension and retraction speed of the left electric push rod is slowed down, and the extension and retraction speed of the right electric push rod is accelerated; if the position of the right electric push rod is ahead of the position of the left electric push rod, the extension and retraction speed of the right electric push rod is slowed down, and the extension and retraction speed of the left electric push rod is accelerated.

[0027] Preferably, in step (2.5), the specific steps of checking whether the two electric push rods after adjustment using the dual electric push rod synchronization algorithm are in a synchronized state are: by reading the output values ​​of the two linear sensors, if the two output values ​​indicate that the two electric push rods are in a synchronized state, repeat step (2.2); if the two output values ​​indicate that the two electric push rods are in an unsynchronized state, repeat step (2.4); if the unsynchronized state still occurs after more than three checks, it is judged that the electric suspension device is faulty and enters a faulty state, and the staff is notified to pay attention to the status of the two electric push rods and perform maintenance.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The electric suspension device of the present invention is driven by an electric push rod. The power source is electricity. It can be directly driven by electric energy to reduce energy loss. Compared with the hydraulic mechanism of traditional tractors, it has higher energy efficiency. The energy conversion efficiency of the electric drive system can reach more than 80%, while the efficiency of the hydraulic system is relatively low, usually around 60%.

[0030] 2. The electric suspension device of the present invention has a simple structure and does not require complicated hydraulic components such as pipes and valves in the hydraulic mechanism. The electric suspension device of the present invention has excellent control performance and fast control response speed, and can achieve more accurate speed and torque control.

[0031] 3. The electric suspension device of the present invention uses two electric push rods to provide multiple parallel and far-apart force fulcrums, which is conducive to the smooth lifting and lowering of the working machine.

[0032] 4. The electric suspension device of the present invention realizes the precise synchronous telescopic movement of the two electric push rods by setting a linear sensor, thereby ensuring the synchronous operation of the two electric push rods and avoiding damage to the electric suspension device; and the angle detection mechanism can accurately detect the swing angle of the parallel linkage mechanism, thereby detecting the height of the current operating tool, and accurately controlling the lifting or lowering height, and realizing precise adjustment of the height of the operating tool with higher control accuracy; realizing intelligent tool operation, making the operating tool fit the ground, and improving operating efficiency.

[0033] 5. A nonlinear control method in the present invention overcomes the nonlinear characteristic problem of the electric push rod, so as to realize the precise motion control of the electric suspension device and the synchronous control of the multi-electric push rod structure.

[0034] 6. A nonlinear control method in the present invention can ensure that the movement of the electric push rod is adjusted quickly, stably and accurately; synchronous control can avoid structural pulling and damage, etc., and ensure the stable operation of the electric suspension device with a multi-electric push rod structure; it has made contributions to the electrification, intelligence and energy saving of tractors. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic three-dimensional structural diagram of one specific embodiment of an electric suspension device for a work tool in the present invention.

[0036] Figure 2 It is a top view of the electric suspension device in the present invention.

[0037] Figure 3 It is a front view of the electric suspension device in the present invention.

[0038] Figure 4 for Figure 3 A partial enlarged view of point A in the middle.

[0039] Figure 5 This is a calibration workflow diagram of the nonlinear control method in the present invention.

[0040] Figure 6 This is a normal operation flow chart of the nonlinear control method in the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0042] Example 1

[0043] See also Figure 1-Figure 3 , this embodiment discloses an electric suspension device for an operating tool, comprising a base 1, a suspension frame 2, a control unit, a parallel linkage mechanism 3 arranged between the base 1 and the suspension frame 2, a connector 4 arranged on the parallel linkage mechanism 3, two electric push rods 5 arranged between the base 1 and the connector 4, a linear sensor 6 for measuring the telescopic length of each electric push rod 5, and an angle detection mechanism 7 for measuring the swing angle of the parallel linkage mechanism 3; wherein, one end of the parallel linkage mechanism 3 is hinged to the base 1, and the other end of the parallel linkage mechanism 3 is hinged to the suspension frame 2; one end of the electric push rod 5 is connected to the base 1, and the other end of the electric push rod 5 is connected to the connector 4; the base 1 is fixedly connected to a new energy electric tractor, and the suspension frame 2 is connected to the operating tool; the electric push rod 5, the linear sensor 6, and the angle detection mechanism 7 are all electrically connected to the control unit.

[0044] One end of the electric push rod 5 in this embodiment is connected to the base 1 through a pin shaft, and the other end is hinged to the connecting member 4.

[0045] See also Figure 1-Figure 3In this embodiment, the two electric push rods 5 are of the same model, specifications, and electrical parameters and are arranged in parallel with each other. The control unit is an ECU, which is installed on a new energy electric tractor. The working tool is a paddy field working tool, which can be one of a rice transplanter, a weeding wheel, and a fertilizer spreader.

[0046] See also Figure 1-Figure 3 The linear sensor 6 is a high-resolution pull-wire displacement linear sensor. Two pull-wire displacement linear sensors are provided in a one-to-one correspondence with the two electric push rods 5. The pull-wire displacement linear sensors are fixed to the electric push rods 5, and the measuring end of the pull-wire displacement linear sensor is connected to the extension end of the electric push rod 5. By providing two pull-wire displacement linear sensors, the two electric push rods 5 can be detected separately, and the extension and retraction length of the electric push rods 5 can be measured in real time.

[0047] See also Figure 1-Figure 3 The pull-wire displacement linear sensor has a measurement range of 0 to 1000 mm and an IP68 waterproof and dustproof rating. It communicates with the control unit using the CANopen communication protocol. A threshold is set for the detection length interval, which spans from the time the electric actuator 5 is extended to its maximum length to the time it is shortened to its minimum length. When the electric actuator 5 is extended to its maximum length or shortened to its minimum length, the output value (reading) corresponding to the pull-wire displacement linear sensor becomes the threshold. The pull-wire displacement linear sensor is used to determine whether the two electric actuators 5 are operating synchronously within the set operating range (length interval). If so, the electric actuators 5 operate according to the originally set task; if not, the electric actuators 5 operate according to the synchronization algorithm.

[0048] See also Figure 1-Figure 3 The parallel linkage mechanism 3 includes two sets of parallel linkage assemblies, each set of parallel linkage assemblies includes two parallel linkages 3-1 arranged vertically and arranged parallel to each other. One end of the linkage 3-1 is hinged to the base 1, and the other end of the linkage 3-1 is hinged to the suspension frame 2. The connecting member 4 is arranged on the linkage 3-1. In the above structure, the parallel linkage mechanism 3, the base 1, and the suspension frame 2 constitute a parallel four-bar linkage mechanism. The connecting member 4 is used to optimize the load-bearing capacity of the electric push rod 5. The electric push rod 5 is hinged to the connecting member 4, so that the movement of the electric push rod 5 can drive the movement of the connecting member 4. Since the connecting member 4 is located between the base 1 and the suspension frame 2, when the connecting member 4 moves, the suspension frame 2 also moves, driving the movement of the work tool.

[0049] The connecting member 4 of this embodiment can be hinged on the connecting rod 3-1, or the connecting member 4 can be fixed to the upper end of the connecting rod 3-1.

[0050] See also Figure 1-Figure 3 There are two bases 1, two sets of parallel connecting rod assemblies are set in one-to-one correspondence with the two bases 1, and two electric push rods 5 are respectively connected to the two bases 1. The base 1 can also be one, and the two electric push rods 5 are respectively connected to both sides of the base 1.

[0051] See also Figure 1-Figure 3 The position of the connector 4 is selected through multiple tests. The connector 4 can optimize the load force distribution of the entire electric suspension device, so that the electric push rod 5 can reach the maximum load capacity within the tolerable rated range. The final test determined that when the distance between the connector 4 and the base 1 is 300mm, the load-bearing performance of the electric push rod 5 reaches the best, and the stability of the structure reaches the best state, effectively avoiding the occurrence of dangerous accidents such as deformation of structural parts or jamming of the electric push rod 5 under heavy load.

[0052] See also Figure 1-Figure 4 The angle detection mechanism 7 includes an angle sensor 7-1 provided on the base 1 and a transmission assembly provided between the angle sensor 7-1 and the connecting rod 3-1. The angle sensor 7-1 is connected to the control unit. The transmission assembly includes a first rotating rod 7-2 and a second rotating rod 7-3. One end of the first rotating rod 7-2 is fixedly connected to the axis of the angle sensor 7-1. The other end of the first rotating rod 7-2 is connected to one end of the second rotating rod 7-3, and the other end of the second rotating rod 7-3 is connected to the connecting rod 3-1. By setting up the above mechanism, as the connecting rod 3-1 moves, the second rotating rod 7-3 will be driven to move, and then the first rotating rod 7-2 will be driven to rotate, causing the axis of the angle sensor 7-1 to rotate, thereby detecting the movement of the parallel linkage mechanism 3 and calculating the current angle of the parallel linkage mechanism 3.

[0053] See also Figure 1-Figure 4 The input voltage of the angle sensor 7-1 is 5V, and the output voltage Hall effect is 0-5V, corresponding to an angle detection range of 360° for the angle sensor 7-1. A threshold is set for the detection angle. When the electric push rod 5 is extended to its maximum length or shortened to its minimum length, the reading of the angle sensor 7-1 becomes the threshold. The threshold serves only as a limit to prevent damage to the work tool. The angle sensor 7-1 is used to determine whether the parallel linkage 3 is operating within the set working range. If so, the electric push rod 5 does not operate. If not, the electric push rod 5 operates according to the movement signal.

[0054] See also Figure 1-Figure 4 , the working principle of the above electric suspension device is:

[0055] During operation, the two electric push rods 5 realize precise synchronous telescopic movement through the linear sensor 6, thereby driving the parallel linkage mechanism 3 to swing, thereby driving the lifting and lowering of the suspension frame 2, and the suspension frame 2 is connected to the working machine, thereby realizing the lifting and lowering of the working machine; the angle detection mechanism 7 can accurately detect the swing angle of the parallel linkage mechanism 3, thereby detecting the height of the current working machine; the control unit can control the extension and retraction of the electric push rod 5 according to the information feedback from the linear sensor 6 and the angle detection mechanism 7, lower the working machine to a specific angle during operation, and lift the working machine when turning in the field to avoid collision between the working machine and the field ridge, which is conducive to the intelligentization of paddy field operation.

[0056] Example 2

[0057] See also Figure 1 , the electric linear actuator 5 will show nonlinear characteristics, especially the electric linear actuator 5 with large load capacity, its nonlinear characteristics are more prominent. The main reasons why the electric linear actuator 5 shows nonlinear characteristics are as follows:

[0058] 1. The electric push rod 5 is usually driven by a DC motor or a stepper motor, which has nonlinear torque-speed characteristics.

[0059] 2. There is also the geometric nonlinearity of the parallel four-bar linkage. The kinematic equation of the parallel four-bar linkage needs to be described with the help of nonlinear relationships such as trigonometric functions, which is one of the sources of nonlinearity in the overall behavior.

[0060] 3. When the force / torque load applied externally to the parallel four-bar linkage changes, due to the geometric topological structure of the mechanism and the coupling relationship between the links 3-1, the internal force on each link 3-1 will show an obvious nonlinear change pattern.

[0061] To address the aforementioned issues, this embodiment discloses a nonlinear control method for achieving precise motion control of an electric suspension device and synchronous control of multiple electric linear actuators 5. This method is highly adaptable to the nonlinear characteristics of various types of linear actuators 5, such as brushed DC motors and stepper motors, effectively addressing the diverse operating conditions of linear actuators 5 within different motion ranges and overcoming the nonlinear characteristics of linear actuators 5. Furthermore, it offers advantages such as strong anti-interference capabilities and low algorithm deployment costs.

[0062] See also Figure 1 and Figure 5-Figure 6 , the nonlinear control method is applied to the electric suspension device, and the nonlinear control method comprises the following steps:

[0063] (1) Before the electric suspension device starts operating for the first time, it is necessary to calibrate the two electric push rods 5 (referred to as push rods) and the two linear sensors 6. Once calibrated once, no further calibration is required during subsequent normal operations. The control unit stores the calibration values ​​obtained from the calibration operation in the internal storage space.

[0064] (2) The electric suspension device starts normal operation (in normal operation, no calibration operation is required):

[0065] (2.1) Initialization: At the beginning of initialization, the control unit reads the calibration value of the internal storage space; the control unit pushes the electric push rod 5 to the reference position determined during calibration based on the calibration value, and checks the output value of the linear sensor 6;

[0066] (2.2) Detecting the real-time position of the electric push rod 5, reading the output values ​​of the two linear sensors 6 through the control unit to detect whether there is any position deviation between the two electric push rods 5; specifically, the control unit reads the output value of the wire-drawn displacement linear sensor in real time through the CANopen protocol, and performs data fusion of the wire-drawn displacement linear sensor based on its characteristics (such as resolution, range, etc.), while taking into account factors such as the installation error and nonlinear error of the wire-drawn displacement linear sensor, and converts the collected digital position signal (output value) into the actual displacement of the electric push rod 5 to ensure the accuracy of the position calculation;

[0067] (2.3) If there is a position deviation between the two electric push rods 5, the direction operation strategy of each electric push rod 5 is determined according to the positive or negative value of the position error;

[0068] (2.4) According to the direction operation strategy, the dual electric push rod 5 synchronization algorithm is used to determine the specific speed of the two electric push rods 5;

[0069] (2.5) Check whether the two electric push rods 5 are in a synchronized state after being adjusted using the dual electric push rod 5 synchronization algorithm.

[0070] See also Figure 1 and Figure 5 In step (1), the specific process of the calibration operation is as follows: a reference position needs to be determined as the initial synchronization state of the two electric push rods 5; the reference position is a fixed position value; after the electric push rods 5 are pushed to the reference position, the two linear sensors 6 are calibrated. At this time, the output values ​​of the two linear sensors 6 are the calibration values, and the control unit stores the calibration values ​​as the reference values ​​of the linear sensors 6. The purpose is to ensure that the two electric push rods 5 maintain a synchronization state when they are in the initial position, which serves as the reference value of the linear sensors 6, so as to ensure the stability and accuracy of the output values ​​of the linear sensors 6 later.

[0071] See also Figure 1 and Figure 5 In step (1), the position where the telescopic length of the electric push rod 5 is the shortest is taken as the reference position. The purpose is to facilitate rapid calibration and make the reference more accurate.

[0072] See also Figure 1 and Figure 6 In step (2.1), the specific steps of checking the output value of the linear sensor 6 are: checking whether the output value of the linear sensor 6 is correct; if correct, entering the initialization success state; if wrong, entering the initialization failure state.

[0073] See also Figure 1 and Figure 6 In step (2.3), the specific steps of determining the directional operation strategy of each electric push rod 5 according to the positive and negative values ​​of the position error are: if the position of the left electric push rod 5 is ahead of the position of the right electric push rod 5, the extension and retraction speed of the left electric push rod 5 is slowed down, and the extension and retraction speed of the right electric push rod 5 is accelerated; if the position of the right electric push rod 5 is ahead of the position of the left electric push rod 5, the extension and retraction speed of the right electric push rod 5 is slowed down, and the extension and retraction speed of the left electric push rod 5 is accelerated.

[0074] In step (2.3), the direction of the push rod extending forward is set as the positive direction, and the direction of the push rod retracting is set as the negative direction; if the error is a positive number, it means that the length of the left electric push rod 5 is greater than the length of the right electric push rod 5. At this time, the direction of the left electric push rod 5 is set to negative, and the direction of the right electric push rod 5 is set to positive, so that the two electric push rods 5 can be quickly synchronized, and the direction strategy is thus determined; if the error is a negative number, it means that the length of the right electric push rod 5 is greater than the length of the left electric push rod 5. At this time, the direction of the right electric push rod 5 is set to negative, and the direction of the left electric push rod 5 is set to positive, so that the two electric push rods 5 can be quickly synchronized, and the direction strategy is thus determined.

[0075] See also Figure 1 and Figure 6 In step (2.5), the specific steps of checking whether the two electric push rods 5 adjusted by the dual electric push rod 5 synchronization algorithm are in a synchronous state are as follows: by reading the output values ​​of the two linear sensors 6, if the two output values ​​indicate that the two electric push rods 5 are in a synchronous state, repeat step (2.2); if the two output values ​​indicate that the two electric push rods 5 are in an asynchronous state, repeat step (2.4); if the asynchronous state still occurs after more than three checks, it is determined that the electric suspension device is faulty and enters a faulty state, and the staff is notified to pay attention to the status of the two electric push rods 5 and perform maintenance.

[0076] See also Figure 1 and Figure 6 In step (2.4), since the motion characteristics of the electric push rod 5 are different in different motion ranges, the system exhibits nonlinear characteristics. Therefore, it is necessary to adopt a dual electric push rod 5 synchronization algorithm to control the pushing speed of the push rod. The dual electric push rod 5 synchronization algorithm is an adaptive algorithm. The dual electric push rod 5 synchronization algorithm of this embodiment adopts a control that integrates a neural network and a nonlinear mathematical model of the electric push rod 5, which effectively adapts to the nonlinear characteristics of the system and improves the control accuracy, thereby making the synchronization process more stable and rapid.

[0077] See also Figure 1 and Figure 6 In actual applications of electric linear actuator 5 control systems, directly using neural networks for end-to-end modeling and control presents challenges such as high computational complexity and strong data dependence. Therefore, this embodiment employs an adaptive decision-making control method based on the fusion of a neural network with a nonlinear mathematical model of the linear actuator 5. The nonlinear mathematical model provides system state predictions, while the neural network controller compensates for model errors and enhances overall control performance. This fusion approach leverages the strengths of both technologies, significantly improving accuracy, robustness, and computational efficiency.

[0078] See also Figure 1 and Figure 6 The steps of the adaptive decision-making method for solving nonlinear problems by integrating neural networks with the nonlinear mathematical model of electric linear actuators are as follows:

[0079] Step 1: Establish a nonlinear mathematical model for the electric linear actuator 5. Model and analyze each component of the electric linear actuator 5 system, including the motor, reducer, and other subsystems. The motor model includes voltage and torque equations, as well as nonlinear relationships such as back electromotive force. The reducer model includes parameters such as gear ratio and efficiency. The electric linear actuator 5 model requires a rigid body dynamics model for the electric linear actuator 5, including parameters such as the mass and length of the electric linear actuator 5. The nonlinear submodels of the motor, reducer, and electric linear actuator 5 are coupled and integrated to form a complete nonlinear mathematical model for the electric linear actuator 5.

[0080] Step 2: Design a neural network controller. Based on the dynamic characteristics of the electric actuator system, select an appropriate neural network topology, including feedforward networks and recurrent neural networks. Determine the network's input and output variables, such as position, velocity, and acceleration. Determine the network's weights, number of hidden layers, number of nodes, and bias parameters to ensure nonlinear approximation and adaptive adjustment. Design an appropriate loss function based on the control objective of minimizing position tracking error.

[0081] Step 3: Train the neural network controller. Using the aforementioned nonlinear model of the electric linear actuator 5, a large number of simulation training data sets are generated. These data sets include input and output data under various operating conditions, covering the entire operating range of the system. The training data is normalized to improve the generalization capability of the neural network. Backpropagation and other efficient optimization methods are used as learning algorithms for a multi-layer neural network with highly nonlinear mapping capabilities to iteratively train the neural network's weights and biases. Based on the training results, the network structure and hyperparameters are appropriately adjusted to improve training convergence speed and control performance. Furthermore, techniques such as transfer learning can be used to leverage existing pre-trained models for further optimization.

[0082] Step 4: Implement control that integrates the neural network with the nonlinear mathematical model of the electric linear actuator 5. Integrate the trained neural network controller and nonlinear mathematical model into the actual electric linear actuator 5 control system, utilizing a high-performance microcontroller or embedded processor to perform the neural network's real-time computations. The nonlinear model provides a prediction of the system state, while the neural network controller compensates for model errors. Using an adaptive mechanism to monitor modeling errors and control performance during system operation and dynamically adjust the weighting between the two, a flexible balance between model accuracy and network generalization performance is achieved.

[0083] Step 5: Performance Verification and Optimization. Through simulation or actual testing, verify the performance of the neural network control method in terms of nonlinearity suppression, tracking accuracy, and robustness. Analyze the control results and, if necessary, optimize the neural network structure and training methods to further improve control performance. Evaluate the computational complexity of the neural network controller to ensure it meets real-time control requirements.

[0084] The fusion of a neural network and the linear actuator's nonlinear mathematical model creates a hybrid control architecture. The nonlinear model provides system state predictions, while the neural network controller compensates for model errors, significantly improving accuracy, robustness, and computational efficiency. The linear actuator's nonlinear mathematical model can generate large amounts of simulation data, which can be used for neural network training and optimization, improving the network's generalization and convergence speed. The neural network's nonlinear fitting capabilities enable modeling of certain relationships in the nonlinear model that are difficult to establish analytically. Furthermore, system analysis and simulation using the nonlinear model can provide guidance for structural selection and parameter optimization of the neural network controller.

[0085] Nonlinear control based on the fusion of a neural network and a nonlinear mathematical model of the electric linear actuator 5 ensures fast, stable, and accurate motion adjustment of the electric linear actuator 5. Synchronous nonlinear control of multiple electric linear actuators 5 prevents structural strain and damage, ensuring stable operation of the electric suspension system with multiple electric linear actuators 5. This has contributed to the electrification, intelligence, and energy conservation of tractors.

[0086] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An electric suspension device for a work tool, characterized in that: The utility model comprises a base, a suspension frame, a control unit, a parallel linkage mechanism provided between the base and the suspension frame, a connecting piece provided on the parallel linkage mechanism, two electric push rods provided between the base and the connecting piece, a linear sensor for measuring the telescopic length of each electric push rod, and an angle detection mechanism for measuring the swing angle of the parallel linkage mechanism; wherein, one end of the parallel linkage mechanism is hinged to the base, and the other end of the parallel linkage mechanism is hinged to the suspension frame; one end of the electric push rod is connected to the base, and the other end of the electric push rod is connected to the connecting piece; the base is fixedly connected to the new energy electric tractor, and the suspension frame is connected to the working tool; the electric push rod, the linear sensor and the angle detection mechanism are all electrically connected to the control unit; The linear sensor is a pull-wire displacement linear sensor, and two pull-wire displacement linear sensors are provided in a one-to-one correspondence with two electric push rods; the pull-wire displacement linear sensor is fixed on the electric push rod, and the rope head measurement end of the pull-wire displacement linear sensor is connected to the telescopic end of the electric push rod; The parallel linkage mechanism includes two sets of parallel linkage assemblies, each set of parallel linkage assemblies includes two connecting rods that are parallel to each other and are arranged vertically, one end of the connecting rod is hinged to the base, and the other end of the connecting rod is hinged to the suspension bracket; the connecting member is arranged on the connecting rod; The angle detection mechanism includes an angle sensor provided on the base and a transmission assembly provided between the angle sensor and the connecting rod, wherein the angle sensor is connected to the control unit; the transmission assembly includes a first rotating rod and a second rotating rod, wherein one end of the first rotating rod is fixedly connected to the axis of the angle sensor; the other end of the first rotating rod is connected to one end of the second rotating rod, and the other end of the second rotating rod is connected to the connecting rod; The distance between the connecting piece and the base is 300 mm.

2. A nonlinear control method, characterized in that: The nonlinear control method is applied to the electric suspension device according to claim 1, and the nonlinear control method comprises the following steps: (1) Before the electric suspension device starts operating for the first time, it is necessary to calibrate the two electric push rods and the two linear sensors. The control unit stores the calibration values ​​obtained by the calibration operation in the internal storage space. (2) The electric suspension device starts to operate normally: (2.1) The control unit reads the calibration value in the internal storage space; the control unit pushes the electric push rod to the reference position determined during calibration according to the calibration value, and checks the output value of the linear sensor; (2.2) Detecting the real-time position of the electric push rods, reading the output values ​​of the two linear sensors through the control unit, and detecting whether there is any position deviation between the two electric push rods; (2.3) If there is a position deviation between the two electric push rods, the direction operation strategy of each electric push rod is determined based on the positive or negative value of the position error; (2.4) Based on the direction operation strategy, a dual electric push rod synchronization algorithm is used to determine the specific speeds of the two electric push rods; (2.5) Check whether the two electric actuators are in synchronization after adjustment using the dual electric actuator synchronization algorithm.

3. A nonlinear control method according to claim 2, characterized in that: In step (1), the specific process of the calibration operation is as follows: a reference position needs to be determined as the initial synchronization state of the two electric push rods; the reference position is a fixed position value; after the electric push rods are pushed to the reference position, the two linear sensors are calibrated. At this time, the output values ​​of the two linear sensors are calibration values, and the control unit stores the calibration values ​​as reference values ​​of the linear sensors.

4. A nonlinear control method according to claim 3, characterized in that: In step (1), the position where the telescopic length of the electric push rod is the shortest is taken as the reference position.

5. A nonlinear control method according to claim 2, characterized in that: In step (2.1), the specific steps for checking the output value of the linear sensor are as follows: checking whether the output value of the linear sensor is correct; if correct, entering the initialization success state; if wrong, entering the initialization failure state.

6. A nonlinear control method according to claim 2, characterized in that: In step (2.3), the specific steps for determining the directional operation strategy of each electric push rod according to the positive and negative values ​​of the position error are as follows: if the position of the left electric push rod is ahead of the position of the right electric push rod, the extension and retraction speed of the left electric push rod is slowed down, and the extension and retraction speed of the right electric push rod is accelerated; if the position of the right electric push rod is ahead of the position of the left electric push rod, the extension and retraction speed of the right electric push rod is slowed down, and the extension and retraction speed of the left electric push rod is accelerated.

7. A nonlinear control method according to claim 2, characterized in that: In step (2.5), the specific steps for checking whether the two electric push rods are in a synchronized state after adjustment using the dual electric push rod synchronization algorithm are as follows: by reading the output values ​​of the two linear sensors, if the two output values ​​indicate that the two electric push rods are in a synchronized state, repeat step (2.2); if the two output values ​​indicate that the two electric push rods are in an unsynchronized state, repeat step (2.4); if the unsynchronized state still occurs after more than three checks, it is determined that the electric suspension device is faulty and enters a faulty state, and the staff is notified to pay attention to the status of the two electric push rods and perform maintenance.

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