CN-122008762-A - Tractor cab active suspension control method based on road surface working condition recognition

CN122008762ACN 122008762 ACN122008762 ACN 122008762ACN-122008762-A

Abstract

The invention belongs to the technical field of self-adaptive control, and particularly relates to an active suspension control method of a tractor cab based on pavement condition recognition, which comprises the steps of carrying out frequency domain analysis on pure vertical acceleration data, and obtaining a frequency domain characteristic index of pavement condition according to the ratio of low-frequency energy integral values to high-frequency energy integral values and root mean square values; the method comprises the steps of obtaining a basic comfortable damping coefficient by combining a pressure fluctuation rate and a frequency domain characteristic index, calculating a protection factor by combining the instantaneous movement speed and the movement direction of a suspension cylinder piston according to the deviation distance of pure telescopic displacement data relative to a locus in a machine, and generating a control instruction based on the product of the basic comfortable damping coefficient and the protection factor. The invention can accurately identify the road surface working condition and dynamically adjust damping, and realizes the soft limit protection of the suspension travel while ensuring riding comfort.

Inventors

MA XUQIANG
Hou Zeyi
CHEN SHAOFENG
WANG BIN
GUO MINGLI
ZHAO LU
YANG JUNFEI
MA HAO

Assignees

山东华首重工有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. The tractor cab active suspension control method based on road surface working condition identification is characterized by comprising the following steps of: The method comprises the steps of obtaining vertical acceleration data of a front axle of a tractor, telescopic displacement data of a suspension cylinder and pressure data of the suspension cylinder, denoising and band-pass filtering the vertical acceleration data, the telescopic displacement data and the pressure data to obtain pure vertical acceleration data, pure telescopic displacement data and pure pressure data; The method comprises the steps of obtaining pressure fluctuation rate according to a difference value between pure pressure data and a preset balance pressure value, obtaining a basic damping coefficient of a suspension system according to a frequency domain characteristic index of a road surface working condition, a pressure fluctuation rate and a preset road working condition basic damping value, performing differential operation on pure telescopic displacement data to obtain an instantaneous movement speed of a suspension cylinder piston, obtaining a protection factor according to a deviation distance of the pure telescopic displacement data relative to pre-recorded mechanical middle-position data in combination with the instantaneous movement speed and movement direction of the suspension cylinder piston, obtaining a target damping control value according to the basic damping coefficient and the protection factor, and generating a final control instruction according to the target damping control value.
2. The tractor cab active suspension control method based on road condition recognition according to claim 1 is characterized in that the obtaining of the vertical acceleration data of a front axle of a tractor, the telescopic displacement data of a suspension cylinder and the pressure data of the suspension cylinder comprises the steps of collecting the vertical acceleration data of the front axle through an acceleration sensor arranged at a front axle head of the tractor, collecting the real-time telescopic displacement data of the suspension cylinder through a displacement sensor arranged at the front end of a frame, and reading the real-time pressure data of a rodless cavity and a rod cavity of the suspension cylinder through a pressure sensor in a hydraulic loop.
3. The tractor cab active suspension control method based on road condition recognition according to claim 1, wherein the performing frequency domain analysis on the clean vertical acceleration data comprises performing fast fourier transform on the clean vertical acceleration data, converting a time domain signal into a frequency domain power spectral density function, and presetting a low frequency band and a high frequency band.
4. The tractor cab active levitation control method based on road condition identification of claim 1, wherein the frequency domain characteristic index satisfies the relation: ; In the formula, Is the frequency domain characteristic index of the road surface working condition, As the value of the energy of the low frequency, In order to be a value of the high frequency energy, Is the root mean square value of the clean vertical acceleration data, Is a linear normalization function.
5. The tractor cab active levitation control method based on road condition recognition of claim 1, wherein the basic damping coefficient satisfies the relation: ; In the formula, As a result of the basic damping coefficient, Is a preset highway working condition basic damping value, Is a frequency domain characteristic index, In order to be a rate of the pressure swing, Is a natural constant which is used for the production of the high-temperature-resistant ceramic material, Is the damping coefficient under the field working condition.
6. The tractor cab active suspension control method based on road condition recognition according to claim 1 is characterized in that the pre-recorded mechanical center point data is obtained by controlling a suspension cylinder to move to a top dead center and a bottom dead center of a physical stroke respectively in an initialization stage of a suspension control system, and recording maximum readings and minimum readings of a displacement sensor, wherein the average value of the maximum readings and the minimum readings is used as the mechanical center point data.
7. The tractor cab active levitation control method based on road condition recognition of claim 1, wherein the protection factor satisfies the relation: ; In the formula, In order to protect the factor(s), For the pure telescopic displacement data, the data is obtained, As the data of the position point in the machine, For the maximum one-way travel allowed by the suspension cylinder, For the instantaneous speed of movement of the piston, Is a linear rectification function.
8. The method for actively suspending control in a tractor cab based on road condition recognition according to claim 1, wherein the step of obtaining the target damping control value according to the base damping coefficient and the protection factor includes taking the product of the base damping coefficient and the protection factor as the target damping control value.
9. The method for actively suspending control of a tractor cab based on road condition recognition according to claim 1, wherein generating the final control command according to the target damping control value comprises calling a pre-calibrated current-damping characteristic mapping table, and converting the target damping control value into a target driving current of a proportional solenoid valve in a front suspending hydraulic control valve group by using the current-damping characteristic mapping table.
10. The method for actively suspending a tractor cab based on road condition recognition according to claim 9, wherein the step of generating a final control command according to the target damping control value further comprises the step of performing PID closed loop correction on the target driving current in combination with a current feedback signal, and the step of controlling the hydraulic oil flow into and out of the accumulator and the hydraulic oil pressure of the suspension cylinder by the suspension hydraulic control valve group before driving.

Description

Tractor cab active suspension control method based on road surface working condition recognition Technical Field The invention relates to the technical field of self-adaptive control. More particularly, the invention relates to a tractor cab active levitation control method based on road surface working condition recognition. Background The tractor is used as core power equipment for modern agricultural production, and the working environment of the tractor covers various complex scenes from soft and fluctuant field cultivation to high-speed transportation on hard road surfaces. The front axle hydraulic suspension system is used as a key component for connecting wheels and a machine body, and has the main function of damping vibration impact caused by road surface unevenness through the synergistic effect of the hydraulic oil cylinder and the energy accumulator, so that riding comfort of a driver and operating stability of the whole machine are improved. Along with the continuous improvement of the operation speed of the high-power tractor, higher requirements are put forward on the control precision and response strategy of the suspension system, and the technical problem to be solved in the field is to be solved, namely, how to realize the self-adaptive adjustment of damping characteristics under the working conditions with huge differences and ensure the safety of the system in a limit state. In the prior art, for example, chinese patent application publication No. CN103713535B discloses an electric suspension control device for a tractor. The device comprises a controller, a control panel, a direct current motor, an angle sensor, a travel switch, a force sensor and the like, wherein the direct current motor drives a lifting arm through a cylindrical gear reduction mechanism and a worm gear reduction mechanism, so as to drive a suspension rod piece to act. The control device realizes comprehensive control of tilling depth control, driving force control and slip through collecting angle, force and wheel speed signals. However, the rigid mechanical transmission structure based on the direct current motor and the worm gear is adopted in the prior art, and is suitable for maintaining the working depth of agricultural implements by utilizing the self-locking characteristic, but lacks the elasticity and damping energy absorption characteristic of a hydraulic suspension system, cannot effectively absorb and filter high-frequency vibration and impact transmitted by a road surface, and is difficult to meet the requirement of front axle suspension on riding comfort, and the control logic in the prior art mainly focuses on the adjustment of the working load and the slip ratio, cannot distinguish two different characteristics of field low-frequency fluctuation and highway high-frequency jolt from the frequency domain dimension, so that the damping strategy cannot be adaptively adjusted for different road conditions. Disclosure of Invention The invention provides an active suspension control method for a tractor cab based on road condition identification, which comprises the steps of obtaining vertical acceleration data of a tractor front axle, telescopic displacement data of a suspension cylinder and pressure data of the suspension cylinder, denoising and bandpass filtering the vertical acceleration data, the telescopic displacement data and the pressure data to obtain pure vertical acceleration data, pure telescopic displacement data and pure pressure data, carrying out frequency domain analysis on the pure vertical acceleration data, obtaining a frequency domain characteristic index of the road condition according to a spectral energy integral value in a preset low frequency range and a spectral energy integral value in a preset high frequency range and a root value of the pure vertical acceleration data, obtaining a pressure fluctuation rate according to a difference value between the pure pressure data and the preset balance pressure value, obtaining a transient motion factor of the suspension cylinder according to the frequency domain characteristic index of the road condition, a dynamic coefficient and a preset obtained by combining the dynamic coefficient of the road condition, obtaining a instantaneous motion factor of the suspension cylinder relative to the instantaneous motion factor of the damping motion of a suspension piston, obtaining a instantaneous motion factor according to the instantaneous motion factor of the suspension damping motion of the suspension cylinder, and obtaining a instantaneous motion factor of the instantaneous damping motion factor of the suspension piston according to the basis damping factor of the suspension motion factor of the suspension cylinder, and generating a final control command according to the target damping control value. According to the invention, the frequency domain characteristic index of the road surface working condition is obtained by carrying out frequency