CN105751847B - A kind of control method of vehicle multi-mode formula shock absorber - Google Patents

Abstract

The invention discloses a control method of a multi-mode shock absorber for a vehicle, which belongs to the field of energy saving and emission reduction of automobiles. The input current of the linear motor three-phase winding coil circuit and the excitation coil circuit in the magneto-rheological shock absorber makes the suspension in active, semi-active and passive damping modes, so that the car can control the suspension at any time when facing different road conditions In order to achieve better ride comfort. At the same time, when the suspension is in passive and semi-active mode, the linear motor can be used to recover part of the vibration energy of the suspension, so as to realize the organic combination of suspension vibration isolation and energy feedback, and achieve the purpose of energy saving and emission reduction.

Description

A control method for a vehicle multi-mode shock absorber

technical field

The invention belongs to the field of automobile energy saving and emission reduction, and in particular relates to a control method of a vehicle multi-mode shock absorber.

Background technique

Shock absorber is a vital part of the car suspension, its performance directly affects the ride comfort of the car. At present, traditional hydraulic shock absorbers are usually used on passive suspensions, and their damping cannot be adjusted, so the corresponding damping cannot be adjusted according to road conditions, etc., and a good vibration damping effect cannot be achieved. At the same time, when the car is running on the road, the body vibrates up and down due to the uneven road surface, and part of the energy of the car is consumed in the form of heat energy during the vibration of the suspension. If this energy is recovered, the fuel consumption will be greatly reduced and the Automobiles have good fuel economy, so the recovery of vibration energy is of great significance.

Magneto-rheological fluid is an intelligent material whose viscosity and yield stress can change with the external magnetic field. It has the characteristics of fast and controllable. It is applied to the shock absorber to continuously and controllably adjust the vibration of the shock absorber mechanical equipment. output, has a good application prospect.

The linear motor is a structural deformation of the rotary motor. Its advantages such as simple structure, high efficiency, and no radial force between the armature and the stator have been applied and developed in various fields.

Chinese patent CN201410176613.0 discloses an energy-feeding suspension system and control method, which judges the energy-feeding by comparing the ideal electromagnetic damping force F _ref with the electromagnetic damping force F _N when the energy-feeding circuit does not contain a DC converter The step-up and step-down modes of the DC converter in the circuit achieve the purpose of effectively recovering energy. However, it only discusses the control method of the energy feeding circuit when the suspension is feeding energy, without considering the change of vehicle dynamic performance, and the control is relatively simple.

Contents of the invention

In order to overcome the above technical defects, the present invention integrates the linear motor into the combined structure of the magneto-rheological shock absorber, proposes a control method for the multi-mode shock absorber of the vehicle, and solves the problem that the change of the dynamic performance of the vehicle is not considered , and the control method is a variety of modes.

A method for controlling a vehicle multi-mode shock absorber, comprising the steps of:

Step 1) Input the vehicle body acceleration measured by the sprung mass acceleration sensor into the ECU controller to determine whether the vehicle body acceleration a and duration t reach a predetermined threshold;

Step 2) If the body acceleration a≤2m/s ² and the duration t>5s;

The ECU controller does not input commands to the semi-active vibration reduction generator and the active vibration reduction generator. At this time, the external power supply does not input current to the excitation coil circuit in the magneto-rheological fluid and the three-phase winding coil circuit of the linear motor. In the passive vibration reduction mode; the linear motor is used as a generator to recover the vibration energy of the suspension: the linear motor output voltage U ₁ and the charging capacitor terminal voltage U _c are measured by the three-phase winding voltage sensor, and the difference between the two is sent to the PI The controller, through analysis and comparison, outputs an appropriate duty cycle to control the conduction time of the switch tube S, so as to boost the voltage at the output terminal of the linear motor and complete the energy recovery process.

Step 3) If the body acceleration is 2m/s ² <a<5m/s ² and the duration t>5s;

The ECU controller only inputs commands to the semi-active vibration reduction generator. At this time, the semi-active vibration reduction generator controls the external power supply to input current to the excitation coil circuit in the magnetorheological fluid. At the same time, the ECU controller controls the sprung mass acceleration sensor and The signal collected by the unsprung mass acceleration sensor is analyzed and processed, and the ideal excitation coil current I _des and the actual current signal I _real in the magneto-rheological fluid are both sent to the semi-active vibration damping generator for tracking control to output an appropriate damping The force F _out puts the suspension in the semi-active vibration reduction mode. While the suspension is semi-actively controlled, the linear motor recovers the vibration energy of the suspension in the generator mode: the linear motor output voltage U ₁ measured by the three-phase winding voltage sensor and the charging capacitor terminal voltage U _c , and transmit the difference between the two to the PI controller. Through analysis and comparison, an appropriate duty cycle is output to control the conduction time of the switch tube S, so as to increase the output terminal voltage of the linear motor. pressure to complete the energy recovery process.

Step 4) If the vehicle body acceleration a≥5m/s ² and the duration t>5s;

The ECU controller only inputs commands to the active vibration reduction generator. At this time, the active vibration reduction generator controls the external power supply to input current to the three-phase winding coil circuit of the linear motor. At the same time, the ECU controller controls the sprung mass acceleration sensor and the unsprung mass The signal collected by the acceleration sensor is analyzed and processed, and the ideal winding coil current I _{des is output. Both the ideal winding coil current I des and} the actual current signal I _real in the linear motor are sent to the active vibration reduction generator for tracking control to output Appropriate force F _out is used to resist the vibration of the vehicle body. At this time, the suspension is in the active damping mode, and the linear motor works in the motor mode to dissipate energy.

Further, the output of the ideal coil current I _des of the winding in the step 4) is to first output the ideal driving force F _des through the ECU controller, and then obtain the ideal coil current I _des of the winding by the formula F _des =K _e · I _des , where K _e is the thrust coefficient of the linear motor.

Further, the vehicle multi-mode shock absorber includes a suspension system and a control system;

The suspension system includes a sprung mass and an unsprung mass of the suspension, one end of the sprung mass and the unsprung mass are respectively fixed with a sprung mass acceleration sensor and an unsprung mass acceleration sensor, and the sprung mass acceleration The sensor and the unsprung mass acceleration sensor are connected to the ECU controller through a signal line, and a suspension spring and a suspension shock absorber are connected in parallel between the sprung mass and the unsprung mass; the suspension shock absorber includes a linear motor and a magnetic rheological shock absorber;

The control system includes a semi-active vibration reduction generator, a rectifier, an active vibration reduction generator, and an ECU controller;

The ECU controller is sequentially connected with a semi-active damping generator and a magneto-rheological damper, and an excitation coil current sensor is arranged between the magneto-rheological damper (15) and the semi-active damper;

The other path of the ECU controller is sequentially connected with an active vibration reduction generator, a rectifier, and a linear motor, and a three-phase winding voltage sensor and a three-phase winding current sensor are arranged between the rectifier and the active vibration reduction generator.

Further, the active vibration damping generator is used to track and control the current situation in the three-phase winding coil of the linear motor; the semi-active vibration damping generator is used to track and control the current situation of the excitation coil in the magneto-rheological fluid.

The beneficial effects of the present invention are: the present invention controls the current input of the three-phase winding coil circuit of the linear motor and the excitation coil circuit in the magneto-rheological shock absorber, so that the vehicle can control the suspension to be active or semi-active when facing different road conditions And passive vibration reduction three working modes, so as to obtain better ride comfort. At the same time, due to the structural characteristics of the linear motor, when it is in the generator mode, the linear motor output voltage U ₁ and the charging capacitor terminal voltage U _c measured by the three-phase winding voltage sensor, and the difference between the two is sent to the PI The controller, through analysis and comparison, outputs an appropriate duty cycle to control the conduction time of the switch S, so as to boost the voltage at the output terminal of the linear motor, recover part of the vibration energy of the suspension, and achieve the purpose of energy saving.

Description of drawings

Fig. 1 is a multi-mode shock absorber system diagram in a control method of a vehicle multi-mode shock absorber according to the present invention;

In the figure: 19-sprung mass acceleration sensor, 20-suspension shock absorber, 21-excitation coil circuit, 22-excitation coil current sensor, 23-three-phase winding current sensor, 24-three-phase winding voltage sensor, 25 -Three-phase winding coil circuit, 26-unsprung mass acceleration sensor, 27-equivalent tire stiffness spring, 28-unsprung mass, 29-suspension spring, 30-sprung mass; - acquisition signal, → - control signal.

2 is a structural diagram of a suspension damper in a control method of a vehicle multi-mode damper according to the present invention;

In the figure: 1-upper lug, 2-mover piston rod, 3-permanent magnet, 4-linear motor, 5-three-phase pie-type armature winding, 6-top cover, 7-electromagnetic piston, 8-excitation coil, 9-Gasket, 10-Cylinder, 11-Nut, 12-Inflation valve, 13-Lower lug, 14-Damp channel, 15-Magneto-rheological shock absorber, 16-Buffer block, 17-Guide seat, 18 - Stator housing.

Fig. 3 is a control scheme diagram of an embodiment of a control method of a vehicle multi-mode shock absorber according to the present invention.

Fig. 4 is a circuit diagram of a linear motor feeding circuit in a control method of a vehicle multi-mode shock absorber according to the present invention.

In the figure: U _m - induced electromotive force, R _coil - equivalent internal resistance of linear motor, L _m - equivalent inductance of linear motor, U ₁ - output voltage of linear motor, L _d - inductance on boost circuit, S - switch tube , U _c - capacitor terminal voltage.

Fig. 5 is a suspension semi-active control strategy diagram in a control method of a vehicle multi-mode shock absorber according to the present invention.

Fig. 6 is a suspension active control strategy diagram in a control method of a vehicle multi-mode shock absorber according to the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

The working principle of the present invention to solve the problems in the prior art is: utilizing the principle that the linear motor can work in both the generator mode and the motor mode, and the variable damping characteristics of the magneto-rheological fluid, the linear motor is integrated into the magnetic current On the variable shock absorber, by controlling the current input of the linear motor and the exciting coil, the vehicle can control the suspension to be in different working modes when the vehicle faces different road conditions, thereby obtaining better ride comfort. At the same time, due to the structural characteristics of the linear motor, when it is in the generator mode, part of the vibration energy can be recovered to achieve the purpose of energy saving.

As shown in Figure 1, the multi-mode shock absorber system diagram in the control method of a vehicle multi-mode shock absorber includes a suspension system and a control system;

The suspension system comprises a sprung mass 30 and an unsprung mass 28 of the suspension, and one end of the sprung mass 30 and the unsprung mass 28 is respectively fixed with a sprung mass acceleration sensor 19 and an unsprung mass acceleration sensor 26, and the sprung mass acceleration The sensor 19 and the unsprung mass acceleration sensor 26 are connected to the ECU controller through the signal line, and the suspension spring 29 and the suspension shock absorber 20 are connected in parallel between the sprung mass 30 and the unsprung mass 28; the suspension shock absorber 20 includes a straight line The motor 4 and the magneto-rheological shock absorber 15; the equivalent tire stiffness spring 27 are in contact with the road surface.

The control system includes a semi-active vibration reduction generator, a rectifier, an active vibration reduction generator, and an ECU controller;

The ECU controller is sequentially connected with a semi-active damping generator and a magneto-rheological damper 15, and an excitation coil current sensor 22 is arranged between the magneto-rheological damper 15 and the semi-active damper; The semi-active damping generator is used to track and control the current of the excitation coil in the magnetorheological fluid.

The other road of the ECU controller is connected with an active damping generator, a rectifier, and a linear motor 4 in sequence, and a three-phase winding voltage sensor 24 and a three-phase winding current sensor 23 are arranged between the rectifier and the active damping generator; The vibration generator is used to track and control the current situation in the three-phase winding coil of the linear motor.

As shown in Figure 2, it is a suspension shock absorber 20 in a control method of a vehicle multi-mode shock absorber according to the present invention, which includes a cylindrical permanent magnet linear motor 4 and a magnetorheological shock absorber 15;

The linear motor 4 includes a mover piston rod 2, a three-phase pie-shaped armature winding 5 and a stator housing 18; on the iron core, and arranged in sequence according to its axial direction;

The magnetorheological shock absorber 15 includes a top cover 6, an electromagnetic piston 7, a cylinder 10, a buffer block 16, and a guide seat 17;

The mover piston 2 is the piston rod of the magneto-rheological shock absorber, which is coaxial with the magneto-rheological shock absorber 15. The lower end of the mover piston rod 2 is connected to the electromagnetic piston 7 through a nut 22; the upper end of the mover piston rod 2 is connected to the upper lug 1 Consolidated together, the lower lug 13 is welded to the bottom end of the suspension shock absorber 20; an annular damping channel is formed between the electromagnetic piston 7 and the cylinder 10, and the excitation coil 8 is fixedly embedded in the middle part of the electromagnetic piston 7; the guide seat 17 is at the upper end of the cylinder 10, and is used to limit the position of the mover piston rod 2; the top cover 6 is used to seal and isolate the upper opening of the cylinder 10.

The mover piston rod 2 adopts a single rod structure, the outlet hole of the mover piston rod 2 is filled and sealed with epoxy resin, and the wire of the excitation coil 8 extends to the outside of the shock absorber through the wire outlet hole of the mover piston rod 2 . Buffer block 16 is made of elastic rubber material.

When the vehicle is running, the suspension system will vibrate due to uneven road surface or other complicated road conditions. At this time, the vehicle body acceleration measured by the sprung mass acceleration sensor 19 is input to the ECU controller to determine the vehicle body acceleration a and the continuous Whether the time t reaches the predetermined threshold determines the working mode of the suspension, as shown in Figure 3:

If the vehicle body acceleration a≤2m/s ² and the duration t>5s, it indicates that the road conditions are good and the vehicle has good ride comfort. The ECU controller does not input commands to the semi-active vibration reduction generator and the active vibration reduction generator. At this time, the external power supply does not input current to the excitation coil circuit 21 in the magnetorheological fluid and the three-phase winding coil circuit 25 of the linear motor. The magneto-rheological shock absorber is equivalent to the traditional oil shock absorber with non-adjustable damping, and the suspension is in the passive damping mode. Due to the relative motion between the vehicle body and the tire, the mover piston rod 2 of the linear motor 4 moves up and down relative to the three-phase winding on the stator. According to Faraday’s law of electromagnetic induction, an induced current will be generated in the coil, and this part of electric energy will be stored in the capacitor. The purpose of energy feeding is achieved, and the linear motor is in the generator mode; however, there will be a "dead zone phenomenon" in the process of feeding the linear motor, that is, when the vibration speed of the suspension is low, the induced electromotive force generated by the linear motor is relatively small. Small, if it is directly connected to the energy storage device, it will not be charged. Therefore, in order to effectively recover the vibration energy of the suspension, a linear motor feed circuit as shown in Figure 4 is proposed. Considering that the direction of the induced current in the three-phase winding coil is constantly changing, four diodes are used to form a rectifier bridge to keep the flow direction of the induced current consistent, thereby charging the capacitor. It should be pointed out that energy recovery can only be completed when the charging voltage is greater than the capacitor terminal voltage. The linear motor 4 output voltage U ₁ and the charging capacitor terminal voltage U _c measured by the three-phase winding voltage sensor 24, and the difference between the two is used as the input of the PI controller (Fig. 4), by adjusting the conduction of the switch tube S The on-time is used to control the duty ratio to achieve the purpose of boosting the voltage at the output terminal of the linear motor 4 , wherein _Uc and U1 are measured by the three _- phase winding voltage sensor 24 .

If the vehicle body acceleration is 2m/s ² <a<5m/s ² , and the duration t>5s, it indicates that the road condition is poor and the ride comfort of the vehicle is slightly reduced. The ECU controller only inputs commands to the semi-active vibration reduction generator. At this time, the semi-active vibration reduction generator controls the external power supply to input current to the excitation coil circuit 21 in the magnetorheological fluid. The input of the current causes the magnetic field around the excitation coil to change. In order to change the rheological characteristics of the magnetorheological fluid to achieve the purpose of changing the damping of the shock absorber, the suspension is in a semi-active damping mode. In order to effectively implement the semi-active control of the suspension, a suspension semi-active control strategy diagram as shown in Figure 5 is proposed. The outer loop is the vehicle dynamics control, and the ideal excitation is obtained according to the system state variables of the vehicle (measured by the sensor). The coil input current I _des , the inner loop is current tracking control, so that the actual current I _real in the excitation coil can follow the ideal excitation coil input current I _des , so that the vehicle maintains good dynamic performance. The semi-active control process of the suspension is: the ECU controller analyzes and processes the signals collected by the sprung mass acceleration sensor 19 and the unsprung mass acceleration sensor 26, and inputs the ideal excitation coil current I _des and the actual current I des in the excitation coil _Real is sent to the semi-active vibration damping generator for tracking control (Fig. 5), so as to output an appropriate damping force F _out to make the vehicle in the semi-active vibration damping mode. While the suspension is under semi-active control, the linear motor feeds The energy circuit recovers the vibration energy of the suspension. The linear motor 4 output voltage U ₁ and the charging capacitor terminal voltage U _c measured by the three-phase winding voltage sensor 24, and the difference between the two is sent to the PI controller (Fig. 4). The duty ratio is used to control the conduction time of the switch tube S to boost the voltage at the output terminal of the linear motor to complete the energy recovery process.

If the vehicle body acceleration a≥5m/s ² and the duration t>3s, it indicates that the road condition is very bad and the ride comfort of the vehicle is obviously reduced. The ECU controller only inputs commands to the active vibration reduction generator. At this time, the active vibration reduction generator controls the external power supply to input current to the linear motor three-phase winding coil circuit 25, the linear motor 4 generates power, and the suspension is in the active vibration reduction mode. . In order to effectively implement the active control of the suspension, the suspension active control strategy diagram shown in Figure 6 is proposed. When the linear motor 4 is used for the active control of the motor, it is mainly to meet the vehicle dynamic performance requirements. At this time, the power source The drive motor generates power, which is given by the formula

F _des =K _e ·I _des (1)

Among them, F _des is the ideal power of the linear motor, K _e is the thrust coefficient of the linear motor, and I _des is the ideal current of the three-phase winding coil of the linear motor;

It can be seen that the driving force provided by the motor is proportional to the coil current, so the essence of active control is current tracking control. The outer loop is the vehicle dynamics control, and the ideal control force is obtained according to the system state variable (which can be measured by the sensor), so as to obtain the ideal control current I _des ; the inner loop is the current tracking control, so that the ideal operating force F _out of the linear motor can be controlled to follow Ideal control to keep the vehicle in good dynamics. The active control process of the suspension is as follows: the ECU controller analyzes and processes the signals collected by the sprung mass acceleration sensor 19 and the unsprung mass acceleration sensor 26, outputs the ideal operating force F _des , and outputs the three-phase winding coil according to formula (1) The ideal current I _des , the ideal current I _des of the three-phase winding coil and the actual current I _real in the three-phase winding coil of the linear motor are both sent to the active vibration reduction generator for tracking control, so as to output an ideal operating force F _out of appropriate size. To resist body vibration, at this time, the suspension is in the active damping mode, and the linear motor works in the motor mode to dissipate energy.

The control method of a vehicle multi-mode shock absorber provided by the present invention has been introduced in detail above. This paper uses specific examples to illustrate the principle and implementation of the present invention. It should be noted that the above description is only for this purpose. The preferred embodiments of the invention are just preferred embodiments, and are not intended to limit the invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. A control method for a vehicle multi-mode shock absorber, comprising the following steps: Step 1) Input the vehicle body acceleration measured by the sprung mass acceleration sensor (19) into the ECU controller, and judge whether the vehicle body acceleration a and duration t reach a predetermined threshold; Step 2) If the body acceleration a≤2m/s ² and the duration t>5s; Neither the ECU controller inputs commands to the semi-active vibration reduction generator nor the active vibration reduction generator. ) input current, the suspension is in passive damping mode; the linear motor (4) reclaims the suspension vibration energy as a generator: the linear motor ( ₄ ) output voltage U1 and the charging capacitor measured by the three-phase winding voltage sensor (24) terminal voltage U _c , and transmit the difference between the two to the PI controller. Through analysis and comparison, the output duty ratio is used to control the conduction time of the switch tube S, so as to boost the output terminal voltage of the linear motor 4 and complete the energy recycling process; Step 3) If the body acceleration is 2m/s ² <a<5m/s ² and the duration t>5s; The ECU controller only inputs commands to the semi-active vibration reduction generator. At this time, the semi-active vibration reduction generator controls the external power supply to input current to the excitation coil circuit (21) in the magneto-rheological fluid. At the same time, the ECU controller controls the sprung mass The signals collected by the acceleration sensor (19) and the unsprung mass acceleration sensor (26) are analyzed and processed, and the ideal excitation coil current I _des and the actual current signal I _real in the magneto-rheological fluid are both sent to the semi-active vibration damping generator for further processing. Tracking control to output the damping force F _out so that the suspension is in a semi-active vibration reduction mode. While the suspension is under semi-active control, the linear motor recovers the vibration energy of the suspension in the generator mode: the three-phase winding voltage sensor (24) The measured output voltage U ₁ of the linear motor (4) and the terminal voltage U _c of the charging capacitor, and transmit the difference between the two to the PI controller. Through analysis and comparison, the output duty ratio is used to control the conduction time of the switch tube S , to boost the voltage at the output terminal of the linear motor to complete the energy recovery process; Step 4) If the vehicle body acceleration a≥5m/s ² and the duration t>5s; The ECU controller only inputs commands to the active vibration reduction generator. At this time, the active vibration reduction generator controls the external power supply to input current to the three-phase winding coil circuit (25) of the linear motor. At the same time, the ECU controller controls the sprung mass acceleration sensor ( 19) and the signals collected by the unsprung mass acceleration sensor (26) are analyzed and processed, and the ideal winding coil current I _des is output, and the ideal winding coil current I _des and the actual current signal I _real in the linear motor (4) are all transmitted Tracking control is carried out for the active vibration reduction generator, and the output power F _out is used to resist the vibration of the vehicle body. At this time, the suspension is in the active vibration reduction mode, and the linear motor works in the motor mode to dissipate energy. 2. the control method of a kind of vehicle multi-mode shock absorber according to claim 1, is characterized in that, in described step 4) output ideal winding coil current I _des is first by ECU controller output ideal operating force F _des , and then obtain the ideal winding coil current I _des by the formula F _des =K _e ·I _des , where K _e is the thrust coefficient of the linear motor. 3. The control method of a vehicle multi-mode shock absorber according to claim 1, wherein the vehicle multi-mode shock absorber comprises a suspension system and a control system; The suspension system comprises a sprung mass (30) and an unsprung mass (28) of the suspension, and one end of the sprung mass (30) and the unsprung mass (28) is respectively fixed with a sprung mass acceleration sensor ( 19) and the unsprung mass acceleration sensor (26), the sprung mass acceleration sensor (19) and the unsprung mass acceleration sensor (26) are connected to the ECU controller by a signal line, and the sprung mass (30) and the unsprung mass acceleration sensor (26) are connected to the ECU controller. A suspension spring (29) and a suspension shock absorber (20) are connected in parallel between the masses (28); the suspension shock absorber (20) includes a linear motor (4) and a magnetorheological shock absorber (15) ; The control system includes a semi-active vibration reduction generator, a rectifier, an active vibration reduction generator, and an ECU controller; The ECU controller is sequentially connected with a semi-active damping generator and a magneto-rheological damper (15), and an excitation coil is arranged between the magneto-rheological damper (15) and the semi-active damper Current sensor (22); The other path of the ECU controller is sequentially connected with an active damping generator, a rectifier, and a linear motor (4), and a three-phase winding voltage sensor (24) and a three-phase winding current sensor are arranged between the rectifier and the active damping generator. (twenty three). 4. The control method of a kind of vehicle multi-mode shock absorber according to claim 3, is characterized in that, described active damping generator is used for tracking and controlling the current situation in the three-phase winding coil of linear motor; The damping generator is used to track and control the current situation of the excitation coil in the magneto-rheological fluid.