CN-121989773-A - Omnidirectional leveling device for hilly and mountain tractor seat and control method

CN121989773ACN 121989773 ACN121989773 ACN 121989773ACN-121989773-A

Abstract

The invention belongs to the technical field of tractor seat adjustment, and particularly relates to an omnidirectional leveling device and a control method for a hilly and mountain tractor seat. The hydraulic execution unit comprises an oil source system, four symmetrically arranged leveling hydraulic cylinders and corresponding electro-hydraulic proportional directional valves. The control method is characterized in that a QBP-PID composite intelligent control strategy integrating a Q learning algorithm, a BP neural network and PID control is adopted. The ECU receives the actual inclination angle signal, takes the horizontal posture as a target, optimizes PID control parameters in real time by utilizing a QBP-PID composite intelligent control strategy, drives the electro-hydraulic proportional directional valve to accurately control the cooperative telescopic movement of each hydraulic cylinder, realizes the rapid, stable and self-adaptive adjustment of the transverse and longitudinal inclination angles of the seat, solves the problem of uncomfortable sitting posture of a driver caused by the fluctuation of the topography of the hilly and mountain tractor, and improves the operation comfort and safety.

Inventors

XU LIYOU
LI CHEN
ZHANG JUNJIANG
LIU MENGNAN
YAN XIANGHAI
ZHANG SHUAI
WU YIWEI

Assignees

河南科技大学

Dates

Publication Date: 20260508
Application Date: 20260330

Claims (6)

1. An omnidirectional leveling device for a hilly and mountain tractor seat is characterized by comprising a gesture sensing unit, a hydraulic control unit and a central controller, The gesture sensing unit detects real-time inclination angle signals of the seat plane (1) relative to the horizontal plane in real time through a double-shaft angle sensor (5) arranged on a seat suspension base (6), and transmits the real-time inclination angle signals to the central controller, wherein the real-time inclination angle signals comprise a transverse real-time inclination angle and a longitudinal real-time inclination angle; the hydraulic execution unit comprises an oil source system, four symmetrically arranged leveling hydraulic cylinders and corresponding electro-hydraulic proportional directional valves, wherein the four electro-hydraulic proportional directional valves are electrically connected with the central controller, each electro-hydraulic proportional directional valve independently controls an oil way of one leveling hydraulic cylinder, each leveling hydraulic cylinder comprises two transverse leveling hydraulic cylinders symmetrically arranged on the transverse center plane of the seat and two longitudinal leveling hydraulic cylinders symmetrically arranged on the longitudinal center plane of the seat, the cylinder body end of each leveling hydraulic cylinder is connected with a ball head of a leveling base (11), and the piston rod end of each leveling hydraulic cylinder is connected with a ball head of a suspension base (6).
2. The omnidirectional leveling device for the hilly and mountain tractor seat according to claim 1, wherein the oil source system of the hydraulic execution unit comprises an oil tank (12), a hydraulic pump (13), a filter (15), a pressure stabilizing valve (18) and a switching valve (20) which are sequentially connected, an oil pressure gauge (17) is arranged on an oil path between the hydraulic pump and the pressure stabilizing valve, an energy accumulator (19) is arranged on an oil path between the pressure stabilizing valve and the switching valve, and the other end of the switching valve (20) is connected with four electrohydraulic proportional directional valves.
3. The omnidirectional leveling device for the hilly and mountain tractor seat according to claim 1, wherein the central controller adjusts the flow and the direction of hydraulic oil entering the rodless cavity and the rod cavity of the corresponding leveling hydraulic rod by controlling the input current of each electrohydraulic proportional directional valve, so as to control the telescopic displacement and the speed of each leveling hydraulic cylinder.
4. An omnidirectional leveling control method for a hilly and mountain tractor seat, characterized by comprising the following steps based on the omnidirectional leveling device as set forth in any one of claims 1-3: Step 1, a double-shaft angle sensor detects real-time inclination angle signals of a seat in real time and sends the real-time inclination angle signals to a central controller, wherein the real-time inclination angle signals comprise transverse real-time inclination angles and longitudinal real-time inclination angles; Step 2, the central controller receives the real-time dip angle signal, and calculates the transverse dip angle error and the longitudinal dip angle error respectively by taking the ideal horizontal posture as a target value; step 3, the central controller adopts a QBP-PID composite intelligent control strategy to independently and cooperatively process the transverse inclination angle error and the longitudinal inclination angle error calculated in the step 2, and generates a control signal; step 4, the central controller generates a control current signal according to the control signal output in the step 3, wherein the control current signal comprises a control current signal of the transverse electrohydraulic proportional direction valve and a control current signal of the longitudinal electrohydraulic proportional direction valve; And 5, controlling the corresponding electrohydraulic proportional directional valve to act according to the control current signal generated in the step 4 by the cooperative control mechanism of the leveling hydraulic cylinders, and adjusting the flow and direction of the oil entering each leveling hydraulic cylinder to enable the two horizontal leveling hydraulic cylinders and the two leveling longitudinal hydraulic cylinders to generate coordinated telescopic movement, so that the posture of a seat suspension base is changed, the actual inclination angle of the seat is close to 0 degree, and the omnidirectional automatic leveling of the seat is realized.
5. The omni-directional leveling control method for a hilly-mountain tractor seat according to claim 4, wherein the QBP-PID composite intelligent control strategy in step 3 comprises: Step 3.1, normalizing the inclination angle error e (k), the first-order difference e (k) -e (k-1) and the second-order difference e (k-1) +e (k-2) of the inclination angle error at the current moment to obtain a normalized inclination angle error, and forming a 3-dimensional input vector [ x 1 , x 2 , x 3 ] serving as the input of the BP neural network; step 3.2, the pre-constructed and trained three-layer BP neural network takes the 3-dimensional input vector as a drive, and calculates and outputs a group of optimal PID control parameters [ K P , K I , K D ] corresponding to the current system state on line in real time through the nonlinear mapping of the internal Sigmoid activation function; Step 3.3, introducing a Q learning algorithm to optimize the BP neural network, wherein a momentum term factor ѱ (k) in a BP neural network weight updating formula is used as an action set A, and the normalized dip angle error input [ x 1 , x 2 , x 3 ] is used as a state set S; Step 3.4, minimizing accumulated errors in the leveling process through a reward function R of a Q learning algorithm, wherein the accumulated errors are defined as R= - (e (k) -0) 2 , and e (k) is the inclination error at the current moment; Step 3.5, the Q learning algorithm learns the optimal strategy by iteratively updating the Q value table, and the Q value iterative equation is expressed as: , Wherein Q k (s k ,a k ) is the Q value of action a k in state s k , alpha is the learning rate, gamma is the discount factor, R (s k+1 ,a k ) is the prize value of action a k ; And 3.6, updating the BP neural network connection weight by adopting a gradient descent method according to an optimal momentum factor ѱ (k) output by a Q learning algorithm, wherein the updating formula is as follows: , Wherein ω ij (k) is the connection weight of the BP neural network input layer and the hidden layer, ω jk (k) is the connection weight of the BP neural network hidden layer and the BP neural network output layer, η is the learning rate, and η >0;J k is the leveling system performance index function.
6. The omnidirectional leveling control method for the hilly and mountain tractor seat, which is disclosed in claim 4, is characterized in that the cooperative control mechanism of the leveling hydraulic cylinders in step 5 is that when the horizontal leveling is judged to be needed, the central controller only performs active, synchronous and symmetrical calculation and control on the output currents of the left and right horizontal leveling hydraulic cylinders based on the horizontal errors, at the moment, the oil paths of the two longitudinal leveling hydraulic cylinders are mutually communicated and are in a hydraulic follow-up state, the displacement of the oil paths is determined passively by the posture kinematic relation of the seat, and when the vertical leveling is judged to be needed, the central controller only performs active control on the front and rear longitudinal leveling hydraulic cylinders, and at the moment, the left and right horizontal leveling hydraulic cylinders are in a hydraulic follow-up state.

Description

Omnidirectional leveling device for hilly and mountain tractor seat and control method Technical Field The invention relates to the technical field of tractor seat adjustment, in particular to an omnidirectional leveling device for a hilly mountain tractor seat and a control method. Background Hilly and mountain land terrains occupy about one third of the arable land area in China, the terrains are fluctuated, the steep slope is narrow, when the tractor works on the terrains, the body of the tractor often inclines and tilts, the driver seat is inclined along with the terrains, the sitting posture is forced to change, fatigue of the driver is easily caused during long-term working, and the working safety and efficiency are influenced. At present, the technology for leveling the posture of the tractor is mainly focused on leveling the whole vehicle body or the chassis, and is realized by adjusting hanging or supporting legs. For example, some combine harvesters or special hillside tractors are equipped with body leveling systems, however, due to the slow response of the body leveling system, the adjustment mass is large, which may affect the center of gravity and stability of the whole vehicle. In contrast, the seat leveling technology directly acts on a driver, has the advantages of small adjusting quality, high response speed and small interference to the whole vehicle, and is a more economic and effective scheme for improving driving comfort. Most existing seat leveling devices or studies are only capable of single-direction (typically lateral) recliner adjustment. For example, the left and right leveling of the seat is realized through one or two oil cylinders, but when the tractor runs on a complex hilly mountain, compound inclination which is often coupled horizontally and longitudinally is generated, and only the horizontal leveling can not solve the problem of forward tilting or backward tilting of the body of a driver, so that the comfort improvement is limited. In terms of control methods, conventional seat leveling mostly adopts simple switch control or classical PID control. The PID control has simple structure, but the parameters are fixed, the uncertainty of system parameters caused by weight change of a driver, various road surface excitation and the like is difficult to adapt, the contradiction exists between the response speed and the overshoot, and the leveling process may not be stable and rapid enough. Although advanced control algorithms such as fuzzy PID and neural network PID have better adaptability in theory, in practical application, the problems of rule dependence, slow convergence or easy sinking into local optimum are often faced, and the control requirements of real-time, rapid and accurate leveling of the seat are difficult to meet. Disclosure of Invention Aiming at the defects of the existing tractor seat leveling technology, the invention aims to provide an omnidirectional leveling device and a control method for a hilly and mountain tractor seat. In order to achieve the purpose, the invention adopts the technical scheme that the omnidirectional leveling device for the hilly and mountain tractor seat comprises: The gesture sensing unit detects real-time inclination angle signals of the seat plane relative to the horizontal plane in real time through a double-shaft angle sensor arranged on the seat suspension base and transmits the real-time inclination angle signals to the central controller, wherein the real-time inclination angle signals comprise transverse real-time inclination angles and longitudinal real-time inclination angles; the hydraulic execution unit comprises an oil source system, four symmetrical leveling hydraulic cylinders and corresponding electro-hydraulic proportional directional valves, wherein the four electro-hydraulic proportional directional valves are electrically connected with the central controller, each electro-hydraulic proportional directional valve independently controls an oil way of one leveling hydraulic cylinder, each leveling hydraulic cylinder comprises two symmetrical leveling hydraulic cylinders arranged on the transverse center plane of a seat, two symmetrical longitudinal leveling hydraulic cylinders arranged on the longitudinal center plane of the seat, the two longitudinal leveling hydraulic cylinders are used for generating moment around a longitudinal axis, the two longitudinal leveling hydraulic cylinders are used for generating moment around the transverse axis, the cylinder body end of each leveling hydraulic cylinder is connected with a leveling base ball head, and the piston rod end of each leveling hydraulic cylinder is connected with a suspension base ball head. Further, the oil source system of the hydraulic execution unit comprises an oil tank, a hydraulic pump, a filter, a pressure stabilizing valve and a switching valve which are sequentially connected, an oil pressure meter is arranged on an oil path between the hydraul