CN1810530A - Switchable vehicle active/semi-active suspension - Google Patents

Abstract

A switchable active/semi-active suspension for vehicles. In order to overcome the defects of complex structure, poor reliability, and high requirements for external conditions in the prior art, the present invention provides a switchable active/semi-active suspension for vehicles that adopts electronic control. The frame system mainly includes a hydraulic cylinder 2 and a spring 9 installed in parallel, which are vertically connected to the frame 1 and the axle 8 respectively. The hydraulic cylinder 2 is then connected to the hydraulic motor 3 through a hydraulic pipeline, and the hydraulic motor 3 is connected to a A DC motor 6 is connected to a storage battery 5 , and a controller 4 is installed between the motor 6 and the storage battery 5 . The invention provides a switchable vehicle active/semi-active suspension system adopting electronic control, which has simple structure, high reliability and wide working range, and has the functions of vehicle active suspension/semi-active suspension, and at the same time considers the vehicle energy The reality of shortage has broad application prospects.

Description

A switchable vehicle active/semi-active suspension

Technical field

The invention belongs to a vehicle damping device, in particular to a vehicle suspension adopting an electronically controlled damping system.

Background technique

The automobile suspension system is the key to improving vehicle ride comfort (riding comfort) and safety (handling stability), reducing dynamic loads to avoid damage to parts, and the suspension system generally consists of springs and dampers. At present, automobile suspensions are divided into three categories: passive suspensions, semi-active suspensions, and active suspensions.

The spring and damper of the passive suspension do not consume external energy during work, and are passively adjusted only by inherent characteristics, which has the advantage of low cost; the active suspension has no fixed elastic characteristics and damping characteristics, and the spring and damper are controlled by the actuator Instead, the actuator can actively respond according to the state quantity of the system and the current excitation situation to suppress the vibration of the system, which has the advantage of good ride comfort; the semi-active suspension uses passive but adjustable parameter and damping elements) to replace the active elements of the actuator, the active suspension becomes a semi-active suspension, also known as a passive active suspension. Semi-active suspension generally adopts stiffness adjustment and damping adjustment. The stiffness adjustment mechanism is generally composed of an air spring or oil-pneumatic spring with variable working volume and a solenoid valve. The effective compression volume of the spring is adjusted through the action of the solenoid valve, so as to achieve the purpose of changing the spring stiffness. In addition, magnetic springs with variable stiffness are also in the research stage. The damping adjustment mechanism can be divided into orifice adjustment and rheological (electrorheological, magnetorheological fluid) adjustment according to the different damping adjustment methods.

In recent years, attention has been paid to the application of rheological smart materials in active/semi-active suspensions. The damping can be changed by controlling the yield stress and viscosity of electrorheological fluids and magnetorheological fluids.

Due to the fixed and uncontrollable elasticity and damping characteristics of passive suspension, it cannot adapt to changes in the road surface. The disadvantages of active suspension, and to a certain extent, achieve a smooth effect similar to that of active suspension. Due to the use of various valve parts in the current throttling-adjusted semi-active suspension, not only the structure is complex, the reliability is poor, but also the response is slow and the working range is narrow. Electrorheological fluid semi-active suspension requires high voltage (6kV) and strong electric field (about 5kV/mm), while magnetorheological fluid requires a strong magnetic field (250kA/m), especially the stability of electrorheological and magnetorheological fluids over time It has not been solved yet, so it is still at the level of laboratory research, and it will take a long time for commercialization.

Contents of the invention

In order to overcome the fixed uncontrollability of the passive suspension, the large energy consumption of the active suspension, the complex structure, and the high cost, as well as the characteristics of the semi-active suspension of the vehicle currently developed, such as the complex structure, poor reliability, and high requirements for external conditions, at the same time, considering the shortage of automobile energy The present invention provides an electronically controlled switchable vehicle active/semi-active suspension system, which is based on an electro-hydraulic actuated energy regenerative vehicle suspension.

The device of the present invention mainly includes two parts of a spring 9 and a damper with variable damping force, wherein the damper is composed of a hydraulic cylinder 2, a hydraulic motor 3, a controller 4 and a DC motor 6. The specific connection relationship: the hydraulic cylinder 2 and the spring 9 installed in parallel are vertically connected with the frame 1 and the axle 8 respectively, the hydraulic cylinder 2 is connected with the hydraulic motor 3 through a hydraulic pipeline, and the hydraulic motor 3 is connected to a DC through a coupling The motor 6 and the DC motor 6 are connected to a storage battery 5 , and the controller 4 is installed between the motor 6 and the storage battery 5 .

The device of the invention is characterized in that the system does not use hydraulic valve parts, has simple structure and wide working range. It also has the function of vehicle active suspension/semi-active suspension. By controlling the power generation/electric torque of the brushless motor, it controls the torque of the hydraulic motor/pump so that the hydraulic cylinder can produce a controllable and variable damping force.

When the vehicle is running, the vibration of the frame 1, the wheels 7 and the axle 8 drives the piston of the hydraulic cylinder 2 to reciprocate, so that the pressure oil flows through the hydraulic motor 3, which drives the hydraulic motor 3 and the coaxially connected brushless motor 6 to rotate. When the motor performs the generator function, energy regeneration can be realized, and the storage battery 5 can be charged. The controller 4 detects the rotation of the brushless motor, which means that the vehicle body is vibrating. By controlling the power generation torque of the brushless motor, the speed of the brushless motor is controlled, the rotation of the hydraulic motor is suppressed, and the damping force of the hydraulic cylinder is controlled to achieve a predetermined damping curve. Get ideal ride comfort and complete semi-active suspension tasks. When the driving surface of the car has large fluctuations or the suspension vibration is severe, when the semi-active function of controlling the torque of the brushless motor cannot meet the ride comfort requirements, under the control of the controller, the power supply is supplied to the motor. At this time, the motor works The electric motor is used, and the hydraulic motor is used as a hydraulic pump, so that the active suspension function can be realized.

The controller 4 of the device of the present invention mainly includes a power supply part, a controller (single-chip microcomputer, DSP chip, PLC programmable controller, etc.), a drive part (drive optocoupler, inverter), a signal collector and the like. The DC power supply is connected to the PWM controller to form a stable terminal voltage, and then connected to the transformer to form a variety of voltages to supply power for subsequent circuits: one voltage is connected to the controller, and the other is connected to the sensor. The controller is connected with the PWM chopper circuit and the A/D and D/A conversion circuits, and the D/A conversion circuit is followed by a drive optocoupler for driving the inverter connected to it, and then connected with a DC motor.

The pressure signal and acceleration signal are received by the sensor, and the signal is input into the control chip integrated with the A/D conversion circuit. Through the appropriate control law, the output signal is converted by D/A, and then the inverter is driven by the drive optocoupler to make it Working in the inverter state, it serves as a bridge for energy conversion between the motor and the power supply. The main function of the inverter is to convert the DC signal into an AC signal, and cooperate with the motor to realize commutation. The PWM control circuit connected with the control chip can realize chopper control, thereby regulating the voltage and adjusting the speed of the motor.

The switchable active/semi-active suspension of the vehicle feeds back the transient output of the vehicle body and wheels to the controller through the acceleration sensor, applies appropriate control laws (such as ceiling control, fuzzy control, etc.) to form a reference control force, and then The actual damping force fed back by the force sensor installed on the hydraulic cylinder 2 is compared, and the active/semi-active suspension control of real-time tracking switching is realized under the action of the PWM control circuit and the inverter.

As a preferred solution of the present invention, the spring 9 may be a coil spring, an air spring or an oil-pneumatic spring, or a leaf spring.

As another preferred solution of the present invention, the hydraulic cylinder 2 may be a double-rod double-acting symmetrical hydraulic cylinder or a single-rod double-acting hydraulic cylinder.

As a third preferred solution of the present invention, the controller 4 can adopt a DSP chip or a single-chip microcomputer or a PLC programmable controller.

The effect that the present invention can achieve:

1) The damper has a significant vibration reduction effect under various road surface inputs (0.5 ~ 20HZ);

2) The comprehensive system of mechanical, electrical and hydraulic suspension has a good frequency response curve in the wide frequency range (0.5 ~ 20HZ);

3) It has power generation function when working in semi-active suspension mode;

4) It can realize semi-active suspension/active suspension function switching.

The invention provides a switchable vehicle active/semi-active suspension system adopting electronic control, which has simple structure, high reliability and wide working range, and has the functions of vehicle active suspension/semi-active suspension, and at the same time considers the vehicle energy The reality of shortage has broad application prospects.

Description of drawings

Fig. 1 is a structural schematic diagram of a switchable vehicle active/semi-active suspension of the present invention

Fig. 2 is a structural block diagram of a control system of a switchable vehicle active/semi-active suspension of the present invention

Detailed ways

The vehicle semi-active suspension of the present invention is mainly composed of a spring, a hydraulic cylinder, a hydraulic motor, a controller and a brushless motor. Two specific design schemes of the device are given here for reference.

Selected vehicle (suspension) basic parameter value range: single suspension mass (body mass) m _s =150kg, non-suspension mass (wheel etc. mass) m _u =35kg, tire stiffness k _t =160000N/m.

Reference design scheme one:

According to the load condition of the suspension, a single-rod double-acting hydraulic cylinder 2 is selected, the inner diameter of the cylinder is about 40mm, and the rod diameter is about 25mm. Gear hydraulic motor 3 (pump) is selected as the actuator: GM5-5 gear motor (also hydraulic pump), theoretical displacement 5.2ml/r, rated pressure 20Mpa, maximum speed 4000r/min, minimum speed 800r/min, Weight 1.9kg. The spring 9 is a helical compression spring: the inner diameter of the spring is 60mm, the diameter of the spring steel wire is 10mm, the number of turns is 20.5, the minimum free length of the spring is 310.5mm, and the spring stiffness is about 16000N/m. Motor 6 is a rare earth permanent magnet brushless DC motor: model ZWH120-500, rated power 500w, rated speed 3000rpm, weight 5kg. The controller chooses the DSP chip as the controller: the model is DSP60f3010. Selection of control circuit components: the force sensor model is LTR-1 tension pressure sensor, the piezoelectric acceleration sensor is SD1407 model, the drive optocoupler is IGBT/MOSFETH316J drive optocoupler produced by Agilent, and the voltage regulator is LM7815 and LM7915. The PWM controller of the power supply is UC3842, and the inverter model is IFXH74N10, 74A, 100V. The specific installation method: the single-rod double-acting symmetrical hydraulic cylinder 2 and the helical compression spring 9 are connected vertically and parallel to the vehicle frame 1 and the axle 8 respectively, the hydraulic cylinder 2 is connected to a hydraulic motor 3, and the hydraulic motor 3 is connected to a rare earth permanent A magnetic brushless DC motor 6 (can be used as a generator), the DC motor 6 is connected to a storage battery 5, and a controller 4 is installed between the motor 6 and the storage battery 5. Both the hydraulic motor and the electric motor are mounted on the frame.

The vibration of the frame 1, the wheels 7 and the axle 8 drives the piston of the single-rod double-acting symmetrical hydraulic cylinder 2 to reciprocate, so that the pressure oil flows through the hydraulic motor 3, driving the hydraulic motor 3 and the coaxially connected brushless motor 6 to rotate , at this time, the motor performs the function of a generator, which can realize energy regeneration and charge the storage battery 5 . When the controller 4 detects that the brushless motor rotates, it means that the vehicle body is vibrating. By controlling the power generation torque of the brushless motor, the damping force of the hydraulic cylinder can be controlled to achieve a predetermined damping curve and complete the semi-active suspension task. Under certain conditions, the control motor is used as an electric motor, and the hydraulic motor is used as a hydraulic pump, so that the active suspension function can be realized.

Reference design scheme two:

According to the load condition of the suspension, a double-rod double-acting symmetrical hydraulic cylinder 2 is selected, the inner diameter of the cylinder is about 40mm, and the rod diameter is about 25mm. The gear hydraulic motor 3 (or hydraulic pump) is selected as the actuator: CMK1004 gear motor, the theoretical displacement is 4.25ml/r, the rated pressure is 16Mpa, the maximum speed is 3000/rmin, and the minimum speed is 600r/min. The spring 9 is a helical compression spring: the inner diameter of the spring is 62mm, the diameter of the spring steel wire is 8mm, the number of turns is 17, the minimum free length of the spring is 346.35mm, and the spring stiffness is about 15734N/m. Motor 6 is a rare earth permanent magnet brushless DC motor: 90ZW, rated power 750w, rated speed 3000rpm. The controller uses a DSP chip as the controller: the model is DSP60f3010. The controller uses a DSP chip as the controller: the model is DSP30f6010. Selection of control circuit components: the force sensor model is LTR-1 tension pressure sensor, the piezoelectric acceleration sensor is SD1407 model, the drive optocoupler is IGBT/MOSFET H316J drive optocoupler, the voltage regulator is LM7815 and LM7915, and the PWM connected to the power supply The controller is UC3842, and the inverter model is IFXH74N10, 74A, 100V.

Installation method: The hydraulic cylinder 2 and the spring 9 are connected vertically and parallel to the frame 1 and the axle 8 respectively, the hydraulic cylinder 2 is connected to a hydraulic motor 3, and the hydraulic motor 3 is connected to a DC motor 6, and the DC motor 6 is connected to a battery 5 , the controller 4 is installed between the motor 6 and the storage battery 5 . The hydraulic motor 3, the DC motor 6 and the controller 4 are integrated and installed together. The vibration of the frame 1, the wheels 7 and the axle 8 drives the piston of the double-rod double-acting symmetrical hydraulic cylinder 2 to reciprocate, so that the pressure oil flows through the hydraulic motor 3, driving the hydraulic motor 3 and the coaxially connected brushless motor 6 to rotate , at this time, the motor performs the function of a generator, which can realize energy regeneration and charge the storage battery 5 . When the controller 4 detects that the brushless motor rotates, it means that the vehicle body is vibrating. By controlling the power generation torque of the brushless motor, the damping force of the hydraulic cylinder can be controlled to achieve a predetermined damping curve and complete the semi-active suspension task. Under certain conditions, the control motor is used as an electric motor, and the hydraulic motor is used as a hydraulic pump, so that the active suspension function can be realized.

The suspension system of the two design schemes can be controlled by a certain control law (such as PID control, ceiling control, fuzzy control, neural network control and other algorithms). These control strategies give the reference control damping force of the hydraulic cylinder, and then compare it with the actual damping force fed back by the force sensor installed on the hydraulic cylinder 2. Under the action of the DSP chip control circuit, the switchable vehicle active/semi-automatic tracking in real time is finally realized. Active Suspension Control.

Claims (5)

1. A switchable vehicle active/semi-active suspension, comprising a spring 9 and a damper with variable damping force, characterized in that the damper includes a hydraulic cylinder 2, a hydraulic motor 3, a controller 4 and a DC motor 6. The hydraulic cylinder 2 and the spring 9 installed in parallel are vertically connected with the frame 1 and the axle 8 respectively, the hydraulic cylinder 2 is connected with the hydraulic motor 3 through hydraulic pipelines, and the hydraulic motor 3 is connected with a DC motor 6 through a coupling , the DC motor 6 is connected to a storage battery 5, and the controller 4 is installed between the motor 6 and the storage battery 5. 2. A switchable vehicle active/semi-active suspension according to claim 1, characterized in that: said controller 4 includes a power supply part, a controller, a drive part and a signal collector, and the drive part includes a drive optocoupler And the inverter, the DC power supply is connected to the PWM controller to form a stable terminal voltage, and then connected to the transformer to form a variety of voltages to supply power for the subsequent circuit: one voltage is connected to the controller, and the other is connected to the sensor; the controller is connected to the PWM chopping wave circuit and A/D, D/A conversion circuit, the D/A conversion circuit is followed by a drive optocoupler for driving the inverter connected to it, and then connected with a DC motor. 3. A switchable vehicle active/semi-active suspension according to claim 1, characterized in that: said spring 9 can be a coil spring or an air spring or an oil-pneumatic spring or a leaf spring. 4. A switchable vehicle active/semi-active suspension according to claim 1, characterized in that: said hydraulic cylinder 2 can be a double-rod double-acting symmetrical hydraulic cylinder or a single-rod double-acting hydraulic cylinder. 5. A switchable vehicle active/semi-active suspension according to claim 2, characterized in that: said controller can use a DSP chip or a single-chip microcomputer or a PLC programmable controller.

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