CN-117087373-B - Automobile suspension vortex-induced vibration energy collection system and control method

CN117087373BCN 117087373 BCN117087373 BCN 117087373BCN-117087373-B

Abstract

The invention discloses an automobile suspension vortex-induced vibration energy collecting system and a control method, wherein the automobile suspension vortex-induced vibration energy collecting system comprises a suspension absorber cylinder, a piezoelectric collecting plate, a linear actuator, a rectifying circuit, an automobile energy storage battery, a vehicle speed sensor, wheels, a displacement sensor and a piezoelectric controller, air enters a region near a suspension mechanism, a karman vortex street is generated behind the suspension absorber cylinder when airflow bypasses the suspension absorber cylinder, the natural frequency of the piezoelectric collecting plate is close to the vortex-shedding frequency of the karman vortex street, vibration is amplified, current is generated by first piezoelectric ceramics due to positive piezoelectric effect and is output to the rectifying circuit from a signal wire, and the current is rectified by the rectifying circuit and is input to the automobile energy storage battery. According to the invention, electric energy can be generated according to positive piezoelectric effect by utilizing vortex-induced vibration at the rear of the shock absorber cylinder, the optimal efficiency position in the collecting process of the piezoelectric collecting plate can be tracked in real time along with the change of the vehicle speed, and the position of the piezoelectric collecting plate is changed by utilizing the inverse piezoelectric effect, so that the energy collecting efficiency is improved.

Inventors

SUN HAOYU
ZHAO WANZHONG
WANG CHUNYAN
ZHOU XIAOCHUAN
LIANG WEIHE
LUAN ZHONGKAI

Assignees

南京航空航天大学

Dates

Publication Date: 20260505
Application Date: 20230920

Claims (9)

1. The system is characterized by comprising a suspension shock absorber cylinder, a piezoelectric collecting plate, a linear actuator, a rectifying circuit, an automobile energy storage battery, a vehicle speed sensor, wheels, a displacement sensor and a piezoelectric controller; The suspension damper cylinder is mechanically connected with the automobile frame; the wheels are arranged below the suspension damper cylinder; the piezoelectric collecting plate is arranged at the rear of the suspension damper cylinder, the piezoelectric collecting plate is mechanically connected with the linear actuator, the piezoelectric collecting plate is electrically connected with the rectifying circuit, a voltage signal generated by the piezoelectric collecting plate is transmitted to the rectifying circuit through a signal wire, the automobile energy storage battery is electrically connected with the rectifying circuit, the rectifying circuit transmits a direct-current signal to the automobile energy storage battery through the signal wire, the linear actuator is mechanically connected with an automobile frame, the vehicle speed sensor is arranged at the rear of a wheel and is used for measuring the rotation speed of the wheel, the vehicle speed sensor is electrically connected with the piezoelectric controller and transmits a vehicle speed signal to the piezoelectric controller through the signal wire, the displacement sensor is mechanically connected with the linear actuator and is used for measuring the moving distance of the linear actuator, the displacement sensor is also electrically connected with the piezoelectric controller and transmits a displacement signal to the piezoelectric controller through the signal wire, and the piezoelectric controller is electrically connected with the linear actuator, and the piezoelectric controller generates a two-phase sinusoidal high-frequency voltage signal with a phase difference of 90 degrees and transmits the two-phase sinusoidal high-frequency signal to the linear actuator through the signal wire; The piezoelectric collecting plate comprises a first piezoelectric ceramic, a substrate and a collecting plate fixing bracket; the first piezoelectric ceramic is stuck on one side surface of the substrate through epoxy resin, the number of the signal wires of the substrate is two, and the signal wires are led out from the internal electrode of the first piezoelectric ceramic and used for outputting current; The linear actuator comprises a driving foot, second piezoelectric ceramics, a sliding block, a sliding rail and a base, wherein one surface of the second piezoelectric ceramics is adhered to the upper surface of the driving foot through epoxy resin, the other surface of the second piezoelectric ceramics is adhered to the lower surface of the sliding block through epoxy resin, the middle of the sliding block penetrates through the sliding rail and is matched with the sliding rail, the upper surface of the sliding block is mechanically connected with a collecting plate fixing support, a protruding portion of the lower surface of the driving foot is in contact with the base, the sliding rail and the base are fixed on an automobile chassis through bolts and nuts, and the collecting plate fixing support is fixed in the sliding block.
2. The system of claim 1, wherein the first and second piezoelectric ceramics are lead zirconate titanate piezoelectric ceramics PZT-5.
3. The system of claim 1, wherein the piezoelectric controller comprises a control calculation module, a driving module and a signal acquisition module; the control calculation module is used for calculating output quantity, and an FPGA chip is selected, and the model is XC7S75-2FGGA676I; The driving module comprises a sinusoidal signal generator, a power amplifier and an optical coupler isolator, wherein the sinusoidal signal generator is used for generating a two-phase sinusoidal driving signal, the power amplifier is used for amplifying the power of the driving signal to enable the driving signal to have loaded energy, and the optical coupler isolator is used for reducing interference between the two-phase signals; the signal acquisition module is used for collecting square wave pulse signals of the vehicle speed sensor and the displacement sensor.
4. The system of claim 1, wherein the rectifying circuit is a signal acquisition amplifier circuit, model TLC2652.
5. The system of claim 1, wherein the piezoelectric collector plate energy collection process specifically comprises: The length of the piezoelectric collecting plate is Width of The height is The piezoelectric collecting plate consists of a base plate and a first piezoelectric ceramic, wherein the length of the base plate is Width of The height is The length of the first piezoelectric ceramic is Width of The height is Height of piezoelectric collector plate The neutral line of the piezoelectric collecting plate is at a height from the bottom surface of the substrate ; Height of neutral line of piezoelectric collecting plate from bottom surface of base plate The method comprises the following steps: ; In the formula, And (3) with Respectively representing the elastic moduli of the first piezoelectric ceramic and the substrate; the section moment of inertia I of the piezoelectric collection plate is expressed as: ; First order natural frequency of piezoelectric collector plate The method comprises the following steps: ; In the formula, Is the cross-sectional area; ; Is the length of the substrate; Is the linear density of the substrate; obtaining the first-order natural frequency of the piezoelectric collecting plate The method comprises the following steps: ; In the formula, For the first linear density of the piezoelectric ceramic, Is the substrate linear density; The natural frequency of the piezoelectric collecting plate is equal to the vortex shedding frequency; According to the clamping mode and the boundary condition, the piezoelectric equation corresponding to the piezoelectric collecting plate is obtained as follows: ; In the formula, Is an electrical displacement; Is the piezoelectric stress coefficient; Is that Is a transposed matrix of (a); is strain; is stress; Is the electric field strength; A dielectric constant at constant strain; The elastic rigidity coefficient is the elastic rigidity coefficient when the field intensity is constant; The piezoelectric collecting plate is simplified into a single-degree-of-freedom piezoelectric vibration system, and the system vibration differential equation is as follows: ; In the formula, Equivalent mass for the piezoelectric collection plate; equivalent damping for the piezoelectric collection plate; equivalent stiffness for the piezoelectric collection plate; Is displacement; Is exciting force; Open circuit voltage is applied to two ends of the piezoelectric collecting plate; the piezoelectric stress coefficient is the piezoelectric stress coefficient of the first piezoelectric ceramic; Equivalent mass of piezoelectric collector plate Expressed as: ; Equivalent stiffness of piezoelectric collector plate Expressed as: ; Equivalent damping of piezoelectric collector plates Expressed as: ; In the formula, A capacitance per unit area of the first piezoelectric ceramic; Is the width of the first piezoelectric ceramic; Is the length of the first piezoelectric ceramic; the total capacitance of the first piezoelectric ceramic; the mechanical loss coefficient of the first piezoelectric ceramic; Damping coefficient The method comprises the following steps: ; In the formula, Is the ratio of the Young's modulus of the first piezoelectric ceramic damping layer to the Young's modulus of the elastic layer of the substrate, , For the young's modulus of the first piezoelectric ceramic damping layer, Young's modulus for the elastic layer of the substrate; Is the ratio of the thickness of the first piezoelectric ceramic damping layer to the thickness of the elastic layer of the substrate, , For the thickness of the first piezoelectric ceramic damping layer, The thickness of the elastic layer of the substrate; The energy conservation equation is: ; Multiplying the piezoelectric area at the same time at the two ends of the electric displacement equation equal sign, and deriving time to obtain: ; both sides multiply by open circuit voltage at the same time And integrating to obtain: ; In the formula, A static capacitance which is the first piezoelectric ceramic; 、 The open circuit voltage and the output current at the two ends of the piezoelectric collecting plate are respectively.
6. A control method of a vortex-induced vibration energy collection system of an automotive suspension, based on the system of any one of claims 1 to 5, characterized by the following steps: 1) The vehicle speed sensor collects vehicle speed information in real time and sends the vehicle speed information to the piezoelectric controller, the piezoelectric controller inquires a parameter table to obtain an ideal position of the piezoelectric collecting plate, the piezoelectric controller outputs a high-frequency sinusoidal voltage signal with a two-phase difference of 90 degrees to the second piezoelectric ceramic, the second piezoelectric ceramic generates traveling wave vibration, the driving foot generates forced vibration, and the driving foot generates forward motion in a friction contact mode with the base; 2) The displacement sensor collects the forward displacement of the driving foot in real time and sends forward position information to the piezoelectric controller, the piezoelectric controller calculates the difference between the ideal position and the actual position of the driving foot, and the driving time of two-phase high-frequency sinusoidal voltage signals of the piezoelectric controller is regulated through proportional-integral-differential control, so that the piezoelectric collecting plate on the driving foot reaches the ideal position; 3) The piezoelectric collecting plate generates output current at an ideal position by utilizing a piezoelectric effect, and the output current is rectified and amplified by the rectifying circuit and then is input to the automobile energy storage battery.
7. The method for controlling a vortex-induced vibration energy harvesting system of an automotive suspension according to claim 6, wherein said step 1) specifically comprises: Setting the wind speed to be 0, enabling the automobile to move relative to the static air, enabling the speed to be consistent with the air flow speed flowing through an automobile suspension damper cylinder, inputting a speed signal to a piezoelectric controller through a signal wire by a speed sensor, storing a parameter table of the preset speed and the ideal position of a piezoelectric collecting plate in the piezoelectric controller, and obtaining the ideal position of the piezoelectric collecting plate under the current speed according to the parameter table; The corresponding relation between the speed of the automobile and the ideal position of the piezoelectric collecting plate is as follows: ; In the formula, The vehicle speed is represented, and x represents the displacement of the piezoelectric collecting plate.
8. The method for controlling a vortex-induced vibration energy harvesting system of an automotive suspension according to claim 7, wherein said step 2) specifically comprises: Difference between ideal position and actual position of piezoelectric collector plate The method comprises the following steps: ; In the formula, For the actual position of the piezoelectric collection plate, Ideal positions for the piezoelectric collection plates; difference between ideal position and actual position of piezoelectric collecting plate As an input to the PID controller, the PID controller controls the output The driving time of the two-phase high-frequency sinusoidal voltage signal for the piezoelectric controller is expressed as: ; In the formula, Is a proportionality coefficient; is an integral constant; is a differential constant; is a control constant.
9. The method according to claim 8, wherein in the step 2), the driving time of the two-phase high-frequency sinusoidal signal is controlled and adjusted by the PID controller, the driving foot and the piezoelectric collecting plate reach the ideal position, and when the traveling wave motion of the driving foot stops, the driving foot cannot continue to move due to the action of friction force, and stops at the ideal position in a self-locking manner.

Description

Automobile suspension vortex-induced vibration energy collection system and control method Technical Field The invention belongs to the technical field of automobile suspension energy collection, and particularly relates to an automobile suspension vortex-induced vibration energy collection system and a control method. Background At present, energy conservation and environmental protection of an automobile become the forefront of technical development, wind energy in the running process of the automobile is inexhaustible, no pollution exists, and therefore, how to collect the wind energy in the running process of the automobile becomes a difficulty in technical development. Because the automobile damper cylinder can generate resistance when in contact with air flow in the running process, and a karman vortex street phenomenon is generated behind the damper cylinder, the vortex street can periodically fall off inside, the rotation directions are opposite, the vortex street is arranged into regular double-line vortex, and resonance can occur if the alternate falling frequency of the vortex street coincides with the acoustic standing wave frequency of an object. The resonance amplifies the amplitude of the object, and the copper plate attached with the piezoelectric ceramic is designed to vibrate in the vortex street to generate current by using the piezoelectric effect. The existing scheme for collecting the energy of the automobile suspension mainly comprises the steps of collecting the vertical vibration energy of the suspension damper, converting the vertical vibration of the suspension damper into the rotational motion energy of the generator and the like, however, the reliability of the methods is not high, the vibration reduction state of the automobile suspension can be influenced by the energy collection, and the driving stability is influenced. The existing wind energy collection only considers the condition of a certain wind speed, namely the automobile runs at a constant speed, vortex-induced vibration is generated when airflow flows through two sides of the suspension damper cylinder, the alternate shedding position and frequency of vortex street vortex are fixed, the position of a copper plate attached with piezoelectric ceramics is relatively fixed, the copper plate is not expanded to be applied to the condition of speed change in the running process of the automobile, and when the wind speed changes, the wake flow of the vortex street at the rear of the suspension damper cylinder is also gradually prolonged, so that the position of the copper plate attached with the piezoelectric ceramics needs to be changed according to the specific speed. In order to keep the maximum energy collection efficiency of the copper plate adhered with the piezoelectric ceramic, the copper plate adhered with the piezoelectric ceramic needs to be actively controlled at the moment, so that the copper plate can perform position change movement according to the vehicle speed condition. Disclosure of Invention Aiming at the defects in the prior art, the invention aims to provide an automobile suspension vortex-induced vibration energy collection system and a control method, so as to solve the problem of low mechanical energy collection efficiency generated by an external wind field in the running process of an automobile in the prior art. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention relates to an automobile suspension vortex-induced vibration energy collecting system, which utilizes piezoelectric ceramics to collect vortex-induced vibration energy behind a suspension damper cylinder, and comprises the suspension damper cylinder, a piezoelectric collecting plate, a linear actuator, a rectifying circuit, an automobile energy storage battery, a vehicle speed sensor, wheels, a displacement sensor and a piezoelectric controller; The suspension damper cylinder is mechanically connected with the automobile frame; the wheels are arranged below the suspension damper cylinder; the piezoelectric collecting plate is arranged at the rear of the suspension damper cylinder, the piezoelectric collecting plate is mechanically connected with the linear actuator, the piezoelectric collecting plate is electrically connected with the rectifying circuit, a voltage signal generated by the piezoelectric collecting plate is transmitted to the rectifying circuit through a signal wire, the automobile energy storage battery is electrically connected with the rectifying circuit, the rectifying circuit transmits a direct-current signal to the automobile energy storage battery through the signal wire, the linear actuator is mechanically connected with an automobile frame, the vehicle speed sensor is arranged at the rear of a wheel and is used for measuring the rotation speed of the wheel, the vehicle speed sensor is electrically connected with the piezoelectric controller and transmits a vehi