CN104015582B - The automobile energy regenerative active suspension system of a kind of stiffness variable and damping - Google Patents

Abstract

The invention discloses a vehicle energy-feeding active suspension system with variable stiffness and damping, which includes a suspension variable stiffness mechanism, a suspension energy feedback mechanism and an active suspension control system; the suspension variable stiffness mechanism includes a small stiffness spring , a magneto-rheological damper and a large stiffness spring; the suspension energy feed mechanism includes a linear motor, an energy feed circuit, and a storage battery that are bidirectionally connected in turn; the active suspension control system includes a controller, and the data input terminal of the controller A vibration measurement processing circuit is connected, and the control output end of the controller is respectively connected with the control input ends of the magneto-rheological damper and the linear motor. The suspension system can automatically adjust the damping and stiffness at the same time to achieve good handling stability and smoothness of the vehicle; the control system responds quickly; the energy consumption is greatly reduced, which meets the requirements of vehicle economy; the structure and control algorithm are simple and easy to operate. It is stable and reliable, has a long service life, and can be easily applied to the existing automobile suspension to realize real-time control.

Description

A vehicle energy-fed active suspension system with variable stiffness and damping

technical field

The invention relates to a suspension system for automobiles, more specifically, to an energy-feeding active suspension system for automobiles with variable stiffness and damping.

Background technique

The automobile suspension system has a great influence on the ride comfort and handling stability of the whole vehicle. Therefore, the suspension system has been widely studied in recent years. At present, the suspension system can be divided into three categories: passive suspension, semi-active suspension and active suspension. Passive suspension is a traditional all-mechanical suspension system. It has the advantages of simple structure, reliable performance, low cost, and no need for additional energy, so it is the most widely used; shortcoming. Semi-active suspension uses passive but parameter-adjustable passive components (usually damping components) to replace the active components of the actuator, which can partially improve ride comfort and handling stability, and its performance is better than that of passive suspensions. It is close to active suspension, and has simple structure, low energy loss and low cost. It is a technology commonly used in mid-to-high-end models on the market. Active suspension is the most advanced suspension technology at present. Active suspension includes a series of complex mechanical and electrified structures, which can achieve the design goal of ideal suspension and can take into account the requirements of vehicle ride comfort and handling stability. Due to its high cost, complex structure, and increased vehicle mass, it is currently only used on high-end models that are not sensitive to price and cost; and the active suspension actuator consumes a lot of energy, resulting in generally low vehicle economy.

Magneto-rheological damper is a new type of damper that realizes real-time adjustable damping of (semi) active suspension system. Different from traditional hydraulic dampers, magnetorheological fluid is a kind of intelligent material. When there is no external magnetic field, it exhibits low-viscosity Newtonian fluid characteristics; under the action of a strong magnetic field, it can express in a short time (milliseconds) The apparent viscosity increases by more than two orders of magnitude, presenting the fluid characteristics of high viscosity and low fluidity, and this change is reversible, continuous, and controllable. The magnetorheological damper made of this material has large damping force and can be controlled. It has the advantages of wide tuning range and quick response. The linear motor has compact structure, low power loss, high fast moving speed, high acceleration, and good high-speed performance; there is no direct contact between the mover (primary) and stator (secondary) of the linear motor, and the stator and mover are both rigid components. , so as to ensure the quietness of the linear motor movement (effectively reducing vehicle noise) and the high rigidity of the core moving parts of the overall mechanism; comprehensively, the linear motor has the advantages of simple structure, high sensitivity, high positioning accuracy, safe and reliable work, fast response speed, and It has the advantages of good dynamic performance, maintenance-free, low motion noise, and long service life.

At present, most of the commonly used active suspension forms are realized by direct coupling of air springs, double-acting cylinders and high-speed response hydraulic control valves, but they all have disadvantages such as slow response, complex structure, large volume, and high energy requirements. At the same time, the existing linear motor active suspension has problems such as complex structure, poor reliability, and difficulty in stiffness adjustment; there are also some active suspensions that use magneto-rheological dampers, but none of them can achieve real-time adjustment of stiffness and damping.

Contents of the invention

The technical problem to be solved by the present invention is to provide a vehicle energy-feeding active suspension structure with variable stiffness and damping. The further purpose is to automatically adjust the damping and stiffness to achieve good handling stability and smoothness of the vehicle; a further purpose The linear motor feed mechanism is used as a damper to absorb impact vibration energy. The energy consumption of the system is greatly reduced, which meets the requirements of vehicle economy; and the control structure is simple, the work is stable and reliable, and the service life is long, and it can be conveniently applied to the existing vehicle suspension to realize real-time control.

In order to solve the above problems, the present invention adopts the following technical solutions:

An automobile energy-feeding active suspension system with variable stiffness and damping, comprising a suspension variable-stiffness mechanism, a suspension energy-feeding mechanism, and an active suspension controller; The first stiffness spring, the magneto-rheological damper and the second stiffness spring between the lower swing arm of the non-independent suspension axle; the first stiffness spring and the second stiffness spring are connected in series; the suspension energy feeding mechanism It includes a linear motor, an energy feed circuit and a storage battery that are sequentially connected bidirectionally, and the linear motor is arranged between the vehicle body and the lower swing arm of the independent suspension or the axle of the non-independent suspension; the active suspension controller inputs the vibration signal of the vehicle body and the axle or wheel vibration signal, the controller outputs the magneto-rheological damper control signal and the linear motor control signal.

As a further preference, the upper end of the piston rod of the magneto-rheological damper is connected to the vehicle body through a connecting flange, and the first stiffness spring is sleeved outside the magneto-rheological damper and against the connecting flange, A sleeve is fixed outside the first stiffness spring on the underside of the vehicle body, the lower end of the magneto-rheological damper is connected to the lower support and the lower support is slidingly fitted in the sleeve, and the upper end of the second stiffness spring is stuck on the lower support The lower end of the second stiffness spring is clamped on a spring support, and the spring support is hinged on the lower swing arm of the independent suspension or the axle of the non-independent suspension.

As a further preference, the upper part of the linear motor is fixed at the stepped hole of the vehicle body through a rubber shock absorber and an annular pressure plate, the linear motor passes through the stepped hole of the vehicle body and the lower end of the linear motor is hinged on the independent suspension Lower swing arm or non-independent suspension axle.

As a further preference, the energy feeding circuit includes a rectifying and filtering circuit and a bidirectional DC/DC converter, and the linear motor, the rectifying and filtering circuit, the bidirectional DC/DC converter and the storage battery are sequentially connected bidirectionally through wires.

As a further preference, the control strategy of the controller includes a skyhook control algorithm and an LQR optimal control algorithm; the skyhook control algorithm regulates the damping force of the magneto-rheological damper; and the LQR optimal control algorithm regulates the working force of the linear motor.

As a further preference, the vibration measurement processing circuit is divided into a vehicle body vibration measurement channel and a vehicle axle or wheel vibration measurement channel.

As a further preference, the vehicle body vibration measurement channel includes a first acceleration sensor, a first signal amplifier and a first RMS circuit connected in sequence, and the signal output end of the first RMS circuit is connected to the data input end of the controller; The vehicle axle or wheel vibration measurement channel also includes a second acceleration sensor, a second signal amplifier and a second RMS circuit connected in sequence, and the signal output end of the second RMS circuit is connected to the data input end of the controller through the A/D converter .

As a further preference, the energy feeding circuit judges the mode of the linear motor by judging the positive or negative of the product of the suspension speed and the power of the linear motor. When it is a positive number or zero, the linear motor is in the motor mode; The motor is in generator mode.

As a further preference, the output of the controller is connected to the damping force control channel and the working force control channel; the damping force control channel and the working force control channel respectively include a power amplifier; the power amplifier is composed of sequentially series adjustable gain Amplifier, PMW pulse width modulator, MOSFET switching power amplifier and a current negative feedback amplifier connected in parallel between the current output end of the MOSFET switching power amplifier and the input end of the adjustable gain amplifier; the MOSFET switching power amplifier outputs a regulated current, and the adjustable gain amplifier The input terminal of the adjustable gain amplifier receives the damping force or the power control signal, and the current negative feedback amplifier feeds back the adjusted current to the input terminal of the adjustable gain amplifier.

As a further preference, the stiffness of the first stiffness spring is smaller than the stiffness of the second stiffness spring.

The beneficial effects of the present invention are:

1. Since the active suspension control system can collect the vibration amplitude signals of the body and axle (or wheels) in real time through its vibration measurement channels of the body and axle (or wheels), and then through the controller according to the collected vibration signals and the pre-stored control The program can adjust the stiffness of the suspension system and the dynamic force of the linear motor in real time. Therefore, the suspension system can automatically adjust the damping and stiffness at the same time to achieve good handling stability and smoothness of the vehicle;

2. The control system responds quickly. In the active suspension control system, each vibration measurement channel and control channel independently and automatically completes the collection, calculation, adjustment and other processes, and the damping force control channel can continuously output regularly changing currents for magnetorheological damping The damping force control of the device; the same can continuously output the regularly changing current through the power control channel, which is used for the power control of the linear motor. Therefore, the response speed of the active suspension control system is fast, and the damping force of the magneto-rheological damper and the power of the linear motor can be accurately adjusted in a very short time.

3. By using the suspension energy feeding mechanism as a damper to absorb the impact vibration energy, the energy consumed by the damping elements in the traditional passive suspension system can be converted into electric energy and stored in the battery, which saves the energy consumption of the active suspension and makes the system The energy consumption is greatly reduced, which meets the requirements of vehicle economy.

4. The structure and control algorithm are simple, the work is stable and reliable, and the service life is long. It can be easily applied to the existing automobile suspension to realize real-time control.

Description of drawings

Fig. 1 is a structural composition block diagram of the present invention.

Fig. 2 is a schematic diagram of the assembly structure of the present invention and a quarter car body.

Fig. 3 is an electrical schematic diagram of the signal amplifier of the present invention.

Fig. 4 is a block diagram of the principle composition of the suspension energy feeding mechanism according to the present invention.

Fig. 5 is a block diagram of the composition of the active suspension control system of the present invention.

In the figure: vibration measurement processing circuit C, controller D, power amplifier E, energy feeding circuit F, storage battery G, first acceleration sensor I, second acceleration sensor J, sprung mass M, unsprung mass m, vehicle body 1 , rubber damping pad 2, bolt 3, linear motor 4, annular pressure plate 5, sliding bearing 6, screw 7, flange bolt 8, piston rod screw 9, small spring upper support 10, connecting flange 11, rubber sleeve 12 , sleeve 13, small stiffness spring 14, magnetorheological damper 15, small spring lower support 16, connecting screw 17, lower support 18, high stiffness spring 19, rubber rod 20, spring support 21, cylindrical pin 22 , lower swing arm or axle 23, pin shaft 24, current amplifying circuit 25, programmable amplifying circuit 26.

detailed description

As shown in Figures 1 and 2, the present invention relates to a vehicle energy-feeding active suspension system with variable stiffness and damping, including a suspension variable stiffness mechanism, a suspension energy-feeding mechanism and an active suspension control system. The suspension variable stiffness mechanism includes small stiffness springs arranged up and down between the sprung mass M (i.e. the vehicle body 1) and the unsprung mass m (i.e. the lower swing arm of the independent suspension or the axle 23 of the non-independent suspension) 14. Magneto-rheological damper 15 (or called magnetorheological shock absorber) and large stiffness spring 19, the unsprung mass m of this embodiment takes the lower swing arm 23 of the independent suspension as an example; the magnetorheological damper The upper end of the piston rod of the device 15 is affixed to a connection flange 11 through the piston rod screw 9, and the connection flange 11 is fixed on the bottom surface of the vehicle body 1 by the flange bolt 8. A small spring upper support 10 is welded on the lower surface of the connecting flange 11. The small stiffness spring 14 is sleeved outside the magneto-rheological damper 15 and the upper end is stuck in the small spring upper support 10 for abutting against the connection method. The flange 11 and the vehicle body 1 are provided with a rubber sleeve 12 between the upper end of the small stiffness spring 14 and the piston rod of the magneto-rheological damper 15. In the upper support 10 of the small spring; a lower support 16 of a small spring is welded at the bottom of the cylinder of the magneto-rheological damper 15, and the lower end of the spring 14 with a small stiffness is stuck in the lower support 16 of the small spring. A sleeve 13 is fixedly welded outside the small stiffness spring 14 on the bottom surface of the vehicle body 1, and the lower end of the cylinder barrel of the magneto-rheological damper 15 is connected to a lower support 18 through a connecting screw 17, and the lower support 18 is located on the sleeve 13. The inner sliding fit and the sliding bearing 6 are installed between the lower support 18 and the sleeve 13 . The upper end of the high stiffness spring 19 is stuck in the lower port of the lower support 18, the lower end of the high stiffness spring 19 is stuck on a spring support 21, and the spring support 21 is hinged to the lower swing arm 23 of the independent suspension through a cylindrical pin 22 superior. The upper end surface of the spring support 21 is located in the large stiffness spring 19 and is fixed with a rubber rod 20, which is used to control the compression stroke of the suspension within a reasonable range.

As shown in FIG. 1 , the suspension energy feeding mechanism includes a linear motor 4 , an energy feeding circuit F and a storage battery G sequentially connected bidirectionally through wires. As shown in Figure 2, the linear motor 4 is arranged between the vehicle body 1 and the lower arm of the independent suspension or the axle 23 of the non-independent suspension; Shock pad 2, the rubber shock absorbing pad 2 is stuck in the stepped hole of the vehicle body 1 and fixed at the stepped hole of the vehicle body 1 by an annular pressure plate 5 and screws 7, and the linear motor 4 is driven by the body 1 The stepped hole passes through and the lower end of the linear motor 4 is hinged on the lower swing arm of the independent suspension or the axle 23 of the non-independent suspension through the pin shaft 24. The present embodiment takes the independent suspension as an example. As shown in Figure 4, the energy feeding circuit F includes a rectification and filtering circuit and a bidirectional DC/DC converter, and the linear motor 4, the rectification and filtering circuit, the bidirectional DC/DC converter and the storage battery G realize bidirectional connect.

As a further preference, the maximum compression and extension stroke of the suspension system can be limited by the internal mechanical limit structure of the linear motor 4, thereby ensuring that the suspension works in a safe and reasonable stroke range. In this way, the functions of limiting the limit of the linear motor 4 as power and recovering energy can be achieved.

As shown in FIG. 5, the active suspension control system is powered by the battery G and includes a controller D for controlling the damping force of the magneto-rheological damper 15 and the power of the linear motor 4. The controller D uses The microcontroller unit MCU is the core, including multiple A/D converters, I/O interfaces, and D/A converters. A vibration measurement processing circuit C is connected to the data input of the controller D, and the control output of the controller D is connected to the control input of the magneto-rheological damper 15 and the linear motor 4 through the damping force control channel and the actuation force control channel respectively. The active suspension control strategy is stored inside the controller D. As a further preference, the control method of the active suspension control strategy adopts the simple and reliable ceiling control algorithm and the LQR optimal control algorithm in the prior art to determine the vibration level and the control strategy table (as shown in Table 1). The damping force of the magneto-rheological damper 15 is regulated by the skyhook control algorithm; LQR is a linear quadratic regulator, and the linear motor 4 is regulated by the LQR optimal control algorithm as power. Controlling the damping force of the magneto-rheological damper 15 and the power of the linear motor 4 through these two efficient algorithms is relatively simple to implement, and can well achieve the ideal control effect, that is, effectively suppress the vertical vibration, pitch and lateral vibration of the vehicle body 1. Tilt movement, improve vehicle handling stability and smoothness.

The vibration measurement processing circuit C is divided into a vehicle body vibration measurement channel and an axle (or wheel) vibration measurement channel, as shown in the double-dot dash line with arrows and the dotted line with arrows in FIG. 5 respectively. The vehicle body vibration measurement channel includes a first acceleration sensor I, a first signal amplifier and a first RMS circuit connected in sequence through wires, and the signal output terminal of the first RMS circuit is input through the data input of the A/D converter and the controller D end connection. The axle (or wheel) vibration measurement channel includes a second acceleration sensor J, a second signal amplifier and a second RMS circuit connected in sequence through wires, and the signal output terminal of the second RMS circuit is connected to the control circuit through an A/D converter. connected to the data input of device D. The first acceleration sensor I is arranged on the vehicle body 1, and the second acceleration sensor J is arranged on the axle (or wheel). The first RMS circuit and the second RMS circuit are root mean square DC conversion circuits (or called root mean square DC converters).

FIG. 3 is an electrical schematic diagram of the first or second signal amplifier. The signal amplifier includes three circuits, the former part is a current amplifying circuit 25, the middle part is a resistor R, and the latter part is a programmable amplifying circuit 26. The current amplifying circuit 25 first amplifies the current of the vehicle axle (or wheel) vibration signal (physical current signal) or vehicle body negative feedback vibration signal (physical current signal) detected by the acceleration sensor to meet the sensitivity requirements, and then converts it through the intermediate resistor R is a physical voltage signal.

The damping force control channel and the operating force control channel are respectively shown in dotted lines with arrows and single dotted lines with arrows in FIG. 5 , and the two control channels include a power amplifier E respectively. The power amplifier E is composed of an adjustable gain amplifier, a PWM pulse width modulator and a MOSFET switching power amplifier connected in series in sequence, and a current negative feedback amplifier connected in parallel between the current output end of the MOSFET switching power amplifier and the input end of the adjustable gain amplifier constitute. The MOSFET switch power amplifier outputs a regulation current, the input terminal of the adjustable gain amplifier receives a damping force or a power control reference signal, and the current negative feedback amplifier feeds back the regulation current to the input terminal of the adjustable gain amplifier.

As shown in Figure 5, the specific implementation details of the active suspension control system of the present invention are as follows:

According to the axle (or wheel) vibration signals collected by the second acceleration sensor J in real time and excited by the actual road surface and transmitted through the tires, six types of axles are divided according to the vibration level and the first column of the control strategy table (see Table 1). (or wheel) vibration level, then according to the vehicle body negative feedback vibration signal under the actual working condition that the first acceleration sensor 1 collects in real time, divide 3 kinds of vibrations according to vibration level and control strategy table (referring to Table 1) shown in the second column level, according to the computer simulation optimization in advance (based on the ceiling control algorithm and the LQR optimal control algorithm), the damper and linear motor 4 control reference signals (current) corresponding to 18 vibration levels are determined, and the above two control reference signals are formed The vibration level and control strategy table (as shown in Table 1) is stored in the memory of the controller D in advance, and is called by the active suspension control program to implement control when the active suspension control system is working.

The vibration level and the vibration level of the control strategy table (shown in the first and second columns in Table 1) are determined according to the minimum amplitude-frequency characteristics at each resonance frequency. When the vehicle is running, the vehicle axle (or wheel) vibration signal (physical current signal) detected by the second acceleration sensor device J is amplified by the second signal amplifier, and then output to the second RMS circuit to convert the vehicle axle (or wheel) Vibration signal (physical voltage signal), sent into the A/D converter of controller D to change into vehicle axle (or wheel) vibration signal (digital current signal); Meanwhile, the vehicle body vibration signal that the first acceleration sensor 1 detects (physical current signal), after being amplified by the first signal amplifier, it is output to the first RMS circuit, and the negative feedback vibration signal (physical voltage signal) of the vehicle body 1 is converted, and the A/D converter sent to the controller D is converted into a vehicle body Vibration signal (digital current signal). In the MCU of the controller D, use the above two vibration signals as the selection basis of the control strategy type, determine the vibration level according to the vibration level and the control strategy table, and output the control reference signal u _i (digital current signal); the control reference signal u _i After being converted into a control reference signal (analog voltage signal) by a D/A converter, it is sent to each power amplifier E, thereby independently controlling the drive current value of the magnetorheological damper 15 and the drive current value of the linear motor 4 corresponding to it, and finally independently The damping force of the magneto-rheological damper 15 and the linear motor 4 are controlled to further reduce the vibration of the vehicle body 1 and achieve the purpose of closed-loop control. As a further preference, each (generally four for a car) axle (or wheel) vibration measurement channel, damping force control channel and power control channel in the active suspension control system is provided by each independent circuit board. , to avoid the shortcomings of interference and insufficient circuit drive capability. In addition, the storage battery G uniformly supplies power to each independent circuit board.

Table 1 Vibration level and control strategy table

In order to ensure the accuracy of the D/A converter, the output control reference signal (analog voltage signal) of the controller D is fixed within 5V, the control gain is changed by adjusting the adjustable gain amplifier, and the damping force and the operating force control signal are respectively to the input of the PWM pulse width modulator. The gain of the adjustable gain amplifier can be adjusted by Calculation, the value of km dynamically changes the gain coefficient of the controller D through the I _/ O interface, so that the drive current values of the magneto-rheological damper 15 and the linear motor 4 actually output by the active suspension control system dynamically change with the road conditions, To achieve the purpose of real-time control. The output voltage of the adjustable gain amplifier is sent to the PWM voltage pulse width modulator, and the PWM pulse width modulator generates square waves with different duty ratios according to the input voltage, and sends this square wave to the MOSFET switching power amplifier to generate 0 - 3.5A different driving currents and 10-50A different driving currents to change the damping force of the magneto-rheological damper 15 and the driving force of the linear motor 4 respectively. In addition, the set current negative feedback amplifier can improve the anti-interference ability of the controller D, and the feedback coefficient can be set between 0.1-0.2.

To realize the recovery of vibration energy, it is required that the linear motor 4 can run in four quadrants, that is, when the speed and the electromagnetic thrust are in the same direction, the linear motor 4 is in the electric state, and the linear motor 4 consumes energy as a motor, and the electric energy flows from the battery G to Linear motor 4 actuator; when the speed and thrust are reversed, the linear motor 4 actuator is in the power generation state, and the electric energy flows from the linear motor 4 to the storage battery G. The energy feeding circuit F performs pattern recognition of the linear motor 4 by judging the positive or negative of the product of the suspension speed and the power (electromagnetic force) of the linear motor 4, and the specific control process is as follows:

(1) When F _ij (z _1ij -z _2ij )≥0, the linear motor 4 is set to the motor mode, the battery G outputs electric energy to the linear motor 4, and the linear motor 4 generates electromagnetic force to suppress the vibration of the vehicle body 1.

(2) When F _ij (z _1ij -z _2ij )<0, the linear motor 4 is set to the generator mode, and the linear motor 4 charges and feeds back electric energy to the storage battery G through a rectification filter circuit and a bidirectional DC/DC converter circuit.

In the above formula, F _ij is respectively set as the driving force (motor output force) of the linear motor actuator at each (generally four for a car) wheel of the car; z _1ij is the position of each (generally four for a car) wheel The vibration velocity of the vehicle body, z _2ij are the vibration velocity of the wheels (or axles) where each linear motor is installed; the values of the subscripts i and j are both 1 or 2, when i is 1, it means the front axle, and i is 2 When j represents the rear axle, when j is 1, it represents the left wheel, and when j is 2, it represents the right wheel. For example: F ₁₂ represents the linear motor of the right front wheel as power, and z ₁₁₂ represents the vibration velocity of the vehicle body at the right front wheel.

Referring to Fig. 4, it is a block diagram showing the circuit principle of the suspension energy feeding mechanism. When the linear motor 4 is working in the fourth quadrant, the actuator is set to the generator mode. When the suspension drives the rotor of the linear motor 4 to move, the stator of the linear motor 4 can generate a feed current. After the action of the bidirectional DC/DC converter, the direct current energy is stored in the storage battery G for use by the magneto-rheological damper 15, the linear motor 4 and other electrical equipment.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (10)

1. an automobile energy regenerative active suspension system for stiffness variable and damping, comprises suspension variation rigidity mechanism, suspension energy regenerative mechanism and Active suspension control device; It is characterized in that: described suspension variation rigidity mechanism comprises the first rigid spring, MR damper and the second rigid spring that are arranged between the lower swing arm of vehicle body and independent suspension or the vehicle bridge of dependent suspension; Described first rigid spring and the series connection of the second rigid spring; Described suspension energy regenerative mechanism comprises the linear electric motors, energy regenerative circuit and the storage battery that are bi-directionally connected successively, and described linear electric motors are located between the lower swing arm of vehicle body and independent suspension or the vehicle bridge of dependent suspension; Described Active suspension control device input body vibrations signal and vehicle bridge or unsteadiness of wheels signal, Active suspension control device exports MR damper control signal and linear electric motors control signal; Described Active suspension control device comprises micro controller unit MCU.

2. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1 and damping, it is characterized in that: the piston rod upper end of described MR damper is connected with described vehicle body by a butt flange, described first rigid spring to be enclosed within outside MR damper and to lean described butt flange, a sleeve is fixed in the outside being positioned at the first rigid spring at lower body face, the lower end of described MR damper connects a undersetting and undersetting is positioned at sleeve bearing fit, described second rigid spring upper end is stuck in undersetting lower end, second rigid spring lower end is stuck on a spring bearing, and described spring bearing is hinged in the lower swing arm of independent suspension or the vehicle bridge of dependent suspension.

3. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1 and damping, it is characterized in that: described linear electric motors top is fixed on the stepped hole place of described vehicle body by Rubber shock-absorbing pad and annular pressing plate, described linear electric motors through the stepped hole of described vehicle body and linear electric motors lower end be hinged in the lower swing arm of independent suspension or the vehicle bridge of dependent suspension.

4. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1,2 or 3 and damping, it is characterized in that: described energy regenerative circuit comprises current rectifying and wave filtering circuit and two-way DC/DC changer, described linear electric motors, current rectifying and wave filtering circuit, two-way DC/DC changer and storage battery realize being bi-directionally connected by wire successively.

5. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1 and damping, is characterized in that: the control policy of described Active suspension control device comprises skyhook control algorithm and LQR optimal control algorithm; Skyhook control algorithm regulation and control MR damper dumping force; LQR optimal control algorithm regulation and control linear electric motors are used as power.

6. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1 and damping, is characterized in that: go back involving vibrations measurement processing circuit, and it is divided into body vibrations Measurement channel and vehicle bridge or unsteadiness of wheels Measurement channel.

7. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 6 and damping, it is characterized in that: described body vibrations Measurement channel comprises the first acceleration pick-up, the first signal amplifier and the RMS circuit that connect successively, a described RMS circuit signal mouth is connected with the data input pin of Active suspension control device; Described vehicle bridge or unsteadiness of wheels Measurement channel comprise the second acceleration pick-up, secondary signal amplifier and the 2nd RMS circuit that connect successively, and described 2nd RMS circuit signal mouth is connected by the data input pin of A/D converter with described Active suspension control device.

8. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1,2 or 3 and damping, it is characterized in that: energy regenerative circuit is by judging the positive and negative pattern judging linear electric motors of the product that suspension velocity and linear electric motors are used as power, when for positive number or zero, linear electric motors are electric motor mode; When for negative, linear electric motors are generator mode.

9. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1 and damping, is characterized in that: described Active suspension control device exports and connects dumping force control channel and the control channel that is used as power; Described dumping force control channel and the control channel that is used as power comprise a power amplifier respectively; Described power amplifier is made up of the variable gain amplifier of connecting successively, PWM pulse width modulator and switch mosfet power amplifier and the Current Negative Three-Point Capacitance amplifier be connected in parallel between the current output terminal of switch mosfet power amplifier and the input end of variable gain amplifier; Described switch mosfet power amplifier Drazin inverse electric current, described variable gain amplifier input end receives dumping force or the control signal that is used as power, the input end that Current Negative Three-Point Capacitance amplifier will regulate current feedback to variable gain amplifier.

10. the automobile energy regenerative active suspension system of a kind of stiffness variable according to claim 1,2 or 3 and damping, is characterized in that: the rigidity of described first rigid spring is less than the rigidity of the second rigid spring.