WO2023056751A1 - Electro-hydraulic integrated steering system and multi-parameter coupling optimization method thereof - Google Patents

Electro-hydraulic integrated steering system and multi-parameter coupling optimization method thereof Download PDF

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WO2023056751A1
WO2023056751A1 PCT/CN2022/092942 CN2022092942W WO2023056751A1 WO 2023056751 A1 WO2023056751 A1 WO 2023056751A1 CN 2022092942 W CN2022092942 W CN 2022092942W WO 2023056751 A1 WO2023056751 A1 WO 2023056751A1
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Prior art keywords
steering
hydraulic
formula
torque
valve
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PCT/CN2022/092942
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French (fr)
Chinese (zh)
Inventor
张自宇
储雨凯
赵万忠
王春燕
周小川
栾众楷
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南京航空航天大学
南京天航智能装备研究院有限公司
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Publication of WO2023056751A1 publication Critical patent/WO2023056751A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D3/00—Steering gears
    • B62D3/02—Steering gears mechanical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/061—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle provided with effort, steering lock, or end-of-stroke limiters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the invention relates to the technical field of vehicle steering, in particular to an electro-hydraulic integrated steering system and a multi-parameter coupling optimization method thereof.
  • the design schemes of the electro-hydraulic hybrid steering system mainly include the following types:
  • the Chinese patent publication number CN111055917A the publication date is 2020.04.24
  • the patent name is "An electro-hydraulic coupling intelligent steering system and mode switching control method”
  • the patent discloses that the structure is to install an electric steering mechanism on the steering column and retain the original hydraulic steering mechanism.
  • this solution will cause steering feedback from the road surface due to the addition of an electric power assist mechanism on the steering column. Being isolated, the driver’s sense of road is poor, and the space utilization of the two systems is scattered and the layout is low.
  • the booster mechanism fails, the system will have serious consequences of being unable to steer; and the Chinese patent publication number CN113212543A, the patent name is "a variable transmission ratio circulating ball type electro-hydraulic steering system and its control method", and the structure disclosed in the patent will be electric.
  • the booster mechanism is installed at the lower end of the original hydraulic steering gear, and the rotary valve in it is replaced by a solenoid valve.
  • this solution adopts solenoid valve control, which requires multiple solenoid valve components with complex structure and high cost, and brings reliability.
  • the installation position of the electric mechanism will ensure a good road feeling and high space utilization, it still has the problem of power failure or system lock-up.
  • the technical problem to be solved by the present invention is to provide an electro-hydraulic integrated steering system and its multi-parameter coupling optimization method for the defects of the background technology, so as to solve the problem that the design scheme of the electro-hydraulic composite steering system in the prior art is difficult to have both Electrification and energy saving, structural integration, safety and reliability, high cost, and only the optimization of the structure alone.
  • the present invention adopts the design scheme of integrating the electric booster mechanism at the bottom of the steering gear of the original hydraulic system, replacing the original worm gear reducer with the planetary gear reducer and retaining the mechanical rotary valve structure in the original hydraulic booster mechanism.
  • the hydraulic mechanism is highly integrated, which can reduce energy consumption through coordinated work.
  • the planetary gear reducer eliminates the hidden danger of system jamming, and retains the low failure rate of the mechanical rotary valve structure, and through the multi-parameter coupling optimization of the system, it can also be guaranteed Maximize system economy while reducing cost, reliability, and road feel.
  • An electric-hydraulic integrated steering system of the present invention includes: a mechanical transmission module, an electric power boost module, a hydraulic power boost module and a control module;
  • the mechanical transmission module includes: steering wheel, steering shaft, universal joint, recirculating ball steering gear, steering rocker arm, steering straight rod, steering knuckle arm, left steering knuckle, left trapezoidal arm, steering tie rod, right trapezoidal arm, right Steering knuckle, left and right wheels;
  • the upper end of the steering shaft is connected to the steering wheel, and the lower end is connected to the upper input end of the recirculating ball steering device through the universal joint;
  • the input end of the steering rocker arm is connected to the output end of the recirculating ball steering gear, and the output end is connected to the steering knuckle arm through the steering straight rod;
  • the left steering knuckle is connected with the left wheel, on which the steering knuckle arm and the left trapezoidal arm are fixed;
  • Both ends of the steering tie rod are respectively connected with the left trapezoidal arm and the right trapezoidal arm;
  • the right steering knuckle is connected with the right wheel, on which the right trapezoidal arm is fixed;
  • the electric booster module includes: a booster motor, a planetary gear reducer and an electromagnetic brake block;
  • the planetary gear reducer includes a sun gear, a planetary gear, a planet carrier and a ring gear;
  • the input end of the sun gear is fixedly connected to the output end of the booster motor, and the output end meshes with the planetary gear;
  • the outer ring of the gear presses against the electromagnetic brake block, and is in a pressing and braking state when no power is applied, and its inner ring meshes with the planetary wheel;
  • the input end of the planet carrier is fixedly connected with the planetary wheel, and its output end is fixedly connected with the lower input end of the recirculating ball diverter;
  • the hydraulic booster module includes: a power cylinder, a bearing, a steering screw, a steering nut, a gear fan, a recirculating ball, a recirculating ball guide, a steering valve, an unloading valve, a one-way valve, a pressure limiting valve, an oil pot, a hydraulic pipeline, Gear pumps and hydraulic motors;
  • the power cylinder is the inner cavity of the recirculating ball diverter
  • the bearing is located in the power cylinder and is set on the upper and lower ends of the steering screw;
  • the upper and lower input ends of the steering screw are the upper and lower input ends of the recirculating ball diverter, and its output end is engaged with the steering nut through the recirculating ball;
  • the circulating ball guide is installed on the steering nut and used as a channel for the circulating flow of the circulating ball;
  • the input end of the gear fan meshes with the rack processed on the steering nut, and its output end is connected with the steering rocker arm;
  • the unloading valve is installed in the steering nut and is used to balance the pressure on both sides of the steering nut when it moves to the limit position;
  • the input end of the gear pump is connected to the output end of the hydraulic motor, its oil inlet is connected to the oil pot through a hydraulic pipeline, and its oil outlet is connected to the steering valve;
  • the oil return port of the oil pot is connected with the steering valve through a hydraulic pipeline, and its oil outlet is connected with the gear pump through a hydraulic pipeline;
  • the pressure limiting valve and the one-way valve are installed between the hydraulic pipeline used to connect the oil outlet of the gear pump and the steering valve and the hydraulic pipeline used to connect the steering valve and the oil return port of the oil pot.
  • the former is used to limit the hydraulic pressure.
  • the pressure of hydraulic oil in the pipeline, the latter is to prevent vacuum in the hydraulic pipeline;
  • the control module includes: an electronic control unit, a steering wheel angle sensor, a torque sensor, and a vehicle speed sensor;
  • the input end of the electronic control unit is electrically connected to the steering wheel angle sensor, torque sensor, and vehicle speed sensor, and its output end is electrically connected to the booster motor and hydraulic motor. , to carry out boost control;
  • the steering wheel angle sensor is installed on the steering wheel to obtain the steering wheel angle signal when the vehicle is turning, and transmit the steering wheel angle signal to the electronic control unit.
  • the torque sensor is installed on the steering shaft to obtain a torque signal and transmit the torque signal to the electronic control unit;
  • the vehicle speed sensor is installed on the vehicle, and is used to transmit the obtained vehicle speed signal to the electronic control unit;
  • the present invention also provides a multi-parameter coupling optimization method for an electro-hydraulic integrated steering system, based on the above system, including the following steps:
  • step (4) Based on the optimization model established in step (4), an optimization algorithm is used to solve the optimal structure and energy management strategy parameters;
  • steps for establishing the mathematical model of the electric-hydraulic integrated steering system in the step (1) are as follows:
  • T s K s ( ⁇ w - ⁇ s ) (2)
  • J w is the moment of inertia of the steering wheel
  • B w is the damping coefficient of the steering wheel
  • K s is the torsion bar stiffness in the torque sensor
  • ⁇ w is the steering wheel angle
  • ⁇ s is the steering shaft angle
  • T w is the input torque of the steering wheel
  • T s is the output torque of the torque sensor.
  • J g is the equivalent moment of inertia of the steering screw and the reduction mechanism of the electric power booster module
  • B g is the equivalent viscous damping coefficient of the steering screw and the reduction mechanism
  • K w is the stiffness of the steering shaft
  • ⁇ g is the rotation angle of the steering screw
  • ⁇ g is the feed efficiency of the steering screw
  • d g is the lead of the steering screw
  • T EPS is the power assist torque of the electric power assist module
  • T p is the equivalent torque of the steering resistance torque on the gear sector
  • r p is the pitch circle radius of the gear sector
  • F HPS is the power boost provided by the hydraulic power booster module
  • d r is the road surface random disturbance torque equivalent to the steering screw.
  • the power assist of the hydraulic module is expressed as:
  • a p is the effective area of the piston of the hydraulic cylinder
  • P A and P B represent the pressure at both ends of the hydraulic cylinder respectively.
  • q is the average displacement of the gear pump
  • P s is the working pressure of the gear pump
  • T hm is the input torque of the gear pump
  • ⁇ is the constant of pi
  • ⁇ is the mechanical efficiency of the hydraulic pump.
  • the average displacement of the gear pump is expressed as:
  • ⁇ is the compensation coefficient
  • m is the gear modulus of the gear pump
  • Z is the number of teeth of the gear pump
  • b is the tooth width of the gear
  • the output flow of the gear pump is expressed as:
  • n is the speed of the gear pump
  • ⁇ V is the volumetric efficiency of the gear pump
  • Q is the output flow of the gear pump.
  • P h is the hydraulic motor power
  • u h is the hydraulic motor armature voltage
  • i h is the hydraulic motor armature current
  • R h is the hydraulic motor armature resistance
  • L h is the armature inductance
  • ⁇ h is the hydraulic motor K h is the counter electromotive force constant.
  • J h is the moment of inertia of the hydraulic motor
  • ⁇ h is the rotation angle of the hydraulic motor
  • B h is the damping coefficient of the hydraulic motor shaft
  • T h is the electromagnetic torque of the hydraulic motor
  • T hm is the output torque of the hydraulic motor.
  • K hi is the torque coefficient of the hydraulic motor.
  • the steering valve model is expressed as:
  • Q V is the total oil inlet flow of the valve body
  • Q L1 and Q L2 are the oil inlet and outlet flow of the power cylinder respectively.
  • C d is the flow coefficient
  • ⁇ P i is the pressure difference between the two sides of the i-th valve port
  • ⁇ is the pressure of the hydraulic oil Density
  • a i is the throttling area of the i-th valve port
  • each valve port of the steering valve is expressed as:
  • ⁇ g - ⁇ l represents the relative rotation angle between the steering screw and the steering valve
  • ⁇ l is the steering valve rotation angle
  • R is the matching radius of the steering valve and the steering screw
  • W 1 is the width of the steering valve cutout
  • W 2 is the pre-opening gap width of the steering valve port in the neutral position
  • L 1 is the axial length of the cutout
  • L 2 is the axial length of the steering valve port.
  • P e is the power of the booster motor
  • u e is the armature voltage of the booster motor
  • i e is the armature current of the booster motor
  • R e is the armature resistance of the booster motor
  • L e is the armature inductance
  • ⁇ e is the booster motor Rotation angle
  • K e is the counter electromotive force constant.
  • J e is the moment of inertia of the booster motor
  • ⁇ e is the rotation angle of the booster motor
  • Be is the damping coefficient of the booster motor shaft
  • T e is the electromagnetic torque of the booster motor
  • T em is the output torque of the booster motor.
  • the electromagnetic torque equation of the booster motor is:
  • K ei is the torque coefficient of the booster motor.
  • the power assist T EPS expression provided by the electric power assist module is:
  • G star is the reduction ratio of the planetary gear reducer.
  • the optimization objective in the step (2) is:
  • ⁇ is the system frequency
  • j is the imaginary number unit
  • X1, Y1, Z1 are the equivalent moment of inertia, damping and stiffness coefficient respectively.
  • T n is the steering demand torque
  • n e is the speed of the assist motor
  • the sensitivity analysis step in the step (3) is:
  • the energy management strategy selected in the step (3) is an energy management strategy based on fuzzy rules
  • the final design variable is the membership function node Oe of the output torque of the electric power booster module in the fuzzy rules, and the hydraulic power booster module
  • the optimization model established in the step (4) is:
  • f 1 (X) is the optimization target of steering road feeling
  • f 2 (X) is the optimization target of steering sensitivity index
  • f 3 (X) is the optimization target of steering energy consumption
  • f 4 (X) is the optimization target of system cost.
  • the optimization method used in the step (5) selects multi-objective particle swarm optimization algorithm, and the specific steps are as follows:
  • the external file Ns is empty, the number of iterations is set to M, and the position and velocity vectors of the i-th particle during the iteration process are expressed as:
  • the individual in the external archives is randomly selected as the historical global optimal position Gbest of the particle:
  • c1 and c2 are learning factors
  • r1 and r2 are random numbers between 0 and 1
  • ⁇ t is the time interval.
  • step (5.7) If the end condition is satisfied, then stop the search, and output the Pareto optimal solution set from the external file, otherwise turn to step (5.3) and recycle until the end to output the Pareto optimal solution set;
  • the present invention has the following beneficial effects by adopting the above technical scheme:
  • the present invention adopts the structure schemes such as integrating the electric booster mechanism at the bottom of the steering gear of the original hydraulic system, replacing the original worm gear reducer with a planetary gear reducer, and retaining the mechanical rotary valve structure in the original hydraulic booster mechanism.
  • the high integration of the steering system assist mechanism also eliminates the road sense isolation problem under the pipe column installation scheme, providing the driver with a good road sense.
  • the system can energize the electromagnetic brake block and disconnect the pair of gears when the electric mechanism fails.
  • a degree of freedom is added to the reducer to realize the fault follow-up of the electric power assist part, eliminating the hidden danger of system jamming.
  • the system proposed by the present invention can further improve the reliability of the steering system through mutual redundancy of multiple actuators and retaining the structure of the mechanical rotary valve.
  • the present invention can also improve the system performance without increasing the total cost of the system, and has great technical advantages and high feasibility.
  • the multi-parameter coupling optimization method proposed by the present invention can realize the joint optimization of the structural assembly parameters and the energy management strategy, so that the energy management strategy and the structural assembly parameters match each other, maximizing the economy of the system.
  • Fig. 1 is the electric-hydraulic integrated steering system schematic diagram of the present invention
  • Fig. 2 is a schematic diagram of a planetary gear reducer of the present invention
  • Fig. 3 is a flow chart of the structure optimization method of the electric-hydraulic integrated steering system of the present invention.
  • Fig. 4 is the optimization algorithm flowchart of the present invention.
  • T s K s ( ⁇ w - ⁇ s ) (2)
  • J w is the moment of inertia of the steering wheel
  • B w is the damping coefficient of the steering wheel
  • K s is the torsion bar stiffness in the torque sensor
  • ⁇ w is the steering wheel angle
  • ⁇ s is the steering shaft angle
  • T w is the input torque of the steering wheel
  • T s is the output torque of the torque sensor.
  • J g is the equivalent moment of inertia of the steering screw and the reduction mechanism of the electric power booster module
  • B g is the equivalent viscous damping coefficient of the steering screw and the reduction mechanism
  • K w is the stiffness of the steering shaft
  • ⁇ g is the rotation angle of the steering screw
  • ⁇ g is the feed efficiency of the steering screw
  • d g is the lead of the steering screw
  • T EPS is the power assist torque of the electric power assist module
  • T p is the equivalent torque of the steering resistance torque on the gear sector
  • r p is the pitch circle radius of the gear sector
  • F HPS is the power boost provided by the hydraulic power booster module
  • d r is the road surface random disturbance torque equivalent to the steering screw.
  • the power assist of the hydraulic module is expressed as:
  • a p is the effective area of the piston of the hydraulic cylinder
  • P A and P B represent the pressure at both ends of the hydraulic cylinder respectively.
  • q is the average displacement of the gear pump
  • P s is the working pressure of the gear pump
  • T hm is the input torque of the gear pump
  • ⁇ is the constant of pi
  • ⁇ is the mechanical efficiency of the hydraulic pump.
  • the average displacement of the gear pump is expressed as:
  • ⁇ is the compensation coefficient
  • m is the gear modulus of the gear pump
  • Z is the number of teeth of the gear pump
  • b is the tooth width of the gear
  • the output flow of the gear pump is expressed as:
  • n is the speed of the gear pump
  • ⁇ V is the volumetric efficiency of the gear pump
  • Q is the output flow of the gear pump.
  • P h is the hydraulic motor power
  • u h is the hydraulic motor armature voltage
  • i h is the hydraulic motor armature current
  • R h is the hydraulic motor armature resistance
  • L h is the armature inductance
  • ⁇ h is the hydraulic motor K h is the counter electromotive force constant.
  • J h is the moment of inertia of the hydraulic motor
  • ⁇ h is the rotation angle of the hydraulic motor
  • B h is the damping coefficient of the hydraulic motor shaft
  • T h is the electromagnetic torque of the hydraulic motor
  • T hm is the output torque of the hydraulic motor.
  • K hi is the torque coefficient of the hydraulic motor.
  • the steering valve model is expressed as:
  • Q V is the total oil inlet flow of the valve body
  • Q L1 and Q L2 are the oil inlet and outlet flow of the power cylinder respectively.
  • C d is the flow coefficient
  • ⁇ P i is the pressure difference between the two sides of the i-th valve port
  • ⁇ is the pressure of the hydraulic oil Density
  • a i is the throttling area of the i-th valve port
  • each valve port of the steering valve is expressed as:
  • ⁇ g - ⁇ l represents the relative rotation angle between the steering screw and the steering valve
  • ⁇ l is the steering valve rotation angle
  • R is the matching radius of the steering valve and the steering screw
  • W 1 is the width of the steering valve cutout
  • W 2 is the pre-opening gap width of the steering valve port in the neutral position
  • L 1 is the axial length of the cutout
  • L 2 is the axial length of the steering valve port.
  • P e is the power of the booster motor
  • u e is the armature voltage of the booster motor
  • i e is the armature current of the booster motor
  • R e is the armature resistance of the booster motor
  • L e is the armature inductance
  • ⁇ e is the booster motor Rotation angle
  • K e is the counter electromotive force constant.
  • J e is the moment of inertia of the booster motor
  • ⁇ e is the rotation angle of the booster motor
  • Be is the damping coefficient of the booster motor shaft
  • T e is the electromagnetic torque of the booster motor
  • T em is the output torque of the booster motor.
  • the electromagnetic torque equation of the booster motor is:
  • K ei is the torque coefficient of the booster motor.
  • the power assist T EPS expression provided by the electric power assist module is:
  • G star is the reduction ratio of the planetary gear reducer.
  • ⁇ is the system frequency
  • j is the imaginary number unit
  • X1, Y1, Z1 are the equivalent moment of inertia, damping and stiffness coefficient respectively.
  • T n is the steering demand torque
  • n e is the speed of the assist motor
  • the optimization method uses the multi-objective particle swarm optimization algorithm, and the specific steps are as follows:
  • the external file Ns is empty, the number of iterations is set to M, and the position and velocity vectors of the i-th particle during the iteration process are expressed as:
  • the individual in the external archives is randomly selected as the historical global optimal position Gbest of the particle:
  • c1 and c2 are learning factors
  • r1 and r2 are random numbers between 0 and 1
  • ⁇ t is the time interval.
  • step (3.7) If the end condition is satisfied, then stop the search, and output the Pareto optimal solution set from the external file, otherwise turn to step (3.3) and recycle until the end to output the Pareto optimal solution set;

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

An electro-hydraulic integrated steering system and a multi-parameter coupling optimization method thereof. The electro-hydraulic integrated steering system comprises a mechanical transmission module, an electric power assisted module, a hydraulic power assisted module, and a control module. A design scheme in which the electric power assisted mechanism is integrated at the bottom of an original hydraulic system steering gear, an original worm gear and worm speed reducer is replaced with a planetary gear speed reducer (18), and a mechanical rotary valve structure in an original hydraulic power assisted mechanism is reserved is adopted. On one hand, the electric and hydraulic mechanisms are highly integrated, and energy consumption can be reduced by the cooperative operation; on the other hand, the road surface information can be fed back in real time, thereby providing clear road feel for a driver. In addition, the system further has the advantages that a plurality of execution mechanisms are redundant with each other, the planetary gear speed reducer (18) eliminates the hidden danger of system jamming, low failure rate of the mechanical rotary valve structure is reserved, etc., and multi-parameter coupling optimization is performed on the system, so that the system economy can be maximized while the cost, reliability and road feel are guaranteed.

Description

一种电液集成式转向系统及其多参数耦合优化方法An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method 技术领域technical field
本发明涉及车辆转向技术领域，尤其是涉及一种电液集成式转向系统及其多参数耦合优化方法。The invention relates to the technical field of vehicle steering, in particular to an electro-hydraulic integrated steering system and a multi-parameter coupling optimization method thereof.
背景技术Background technique
目前，随着国家双碳政策的下达，以及汽车“新四化”的行业发展趋势，各大车企都在推进汽车电动化的研发进度，就乘用车而言由于其体积小质量轻，现有电动汽车技术已经日趋完善。然而对于商用车和专用车来说，其具有体积大、质量大等特点，受限于目前电池及电机功率等级限制，还难以实现全车的电动化，尤其是其核心底盘部件之一的转向系统，更是受制于车辆前轴载荷过大而无法实现电动化，其带来的能耗问题致使商用车及专用车难以跟进国家战略发展需求。At present, with the issuance of the national dual-carbon policy and the development trend of the "new four modernizations" of the automobile industry, major automobile companies are promoting the research and development of automobile electrification. As far as passenger cars are concerned, due to their small size and light weight, Existing electric vehicle technology has been perfected day by day. However, for commercial vehicles and special-purpose vehicles, they have the characteristics of large volume and high mass. Limited by the current battery and motor power level, it is difficult to realize the electrification of the whole vehicle, especially the steering, which is one of its core chassis components. The system is also limited by the excessive load on the front axle of the vehicle and cannot be electrified. The energy consumption problem caused by it makes it difficult for commercial vehicles and special vehicles to follow the national strategic development needs.
针对这一问题，目前有研究人员提出了一种电液复合式的转向系统，借鉴于混合动力技术的成功案例，其在原有液压助力转向系统中加入一套电动助力转向系统，通过与液压助力系统的协调运行，实现商用车及专用车转向系统的部分电动化，利用电动助力转向系统的节能优势，降低现有车辆的转向能耗。In response to this problem, some researchers have proposed an electro-hydraulic composite steering system. Drawing on the successful cases of hybrid technology, it adds an electric power steering system to the original hydraulic power steering system. The coordinated operation of the system realizes the partial electrification of the steering system of commercial vehicles and special vehicles, and uses the energy-saving advantages of the electric power steering system to reduce the steering energy consumption of existing vehicles.
目前电液复合式的转向系统的设计方案主要有以下几种：例如，中国专利公开号CN111055917A，公开日2020.04.24，专利名称为“一种电液耦合智能转向系统及模式切换控制方法”，该专利公开了结构为在转向管柱上加装电动转向机构，并保留原液压转向机构，但这种方案一方面由于在转向管柱上加装了电动助力机构，会造成来自路面的转向反馈被隔绝，驾驶员的路感较差，且两套系统分散布局空间利用度低，另一方面现有电动助力部分的蜗轮蜗杆减速器也存在断电或故障自锁问题，一旦加装的电动助力机构故障，系统会出现无法转向的严重后果；而中国专利公开号CN113212543A，专利名 称为“一种变传动比循环球式电液转向系统及其控制方法”，该专利公开的结构中将电动助力机构加装在原有液压转向器的下端，且其中的转阀替换为电磁阀，但这种方案一方面采用电磁阀控制需要多个电磁阀组件结构复杂且成本较高，且带来的可靠性问题也难以忽视，另一方面其电动机构的加装位置虽会保证良好的路感，且空间利用度高，但其仍然存在断电或故障系统锁死的问题。At present, the design schemes of the electro-hydraulic hybrid steering system mainly include the following types: For example, the Chinese patent publication number CN111055917A, the publication date is 2020.04.24, and the patent name is "An electro-hydraulic coupling intelligent steering system and mode switching control method", The patent discloses that the structure is to install an electric steering mechanism on the steering column and retain the original hydraulic steering mechanism. However, on the one hand, this solution will cause steering feedback from the road surface due to the addition of an electric power assist mechanism on the steering column. Being isolated, the driver’s sense of road is poor, and the space utilization of the two systems is scattered and the layout is low. If the booster mechanism fails, the system will have serious consequences of being unable to steer; and the Chinese patent publication number CN113212543A, the patent name is "a variable transmission ratio circulating ball type electro-hydraulic steering system and its control method", and the structure disclosed in the patent will be electric. The booster mechanism is installed at the lower end of the original hydraulic steering gear, and the rotary valve in it is replaced by a solenoid valve. However, on the one hand, this solution adopts solenoid valve control, which requires multiple solenoid valve components with complex structure and high cost, and brings reliability. On the other hand, although the installation position of the electric mechanism will ensure a good road feeling and high space utilization, it still has the problem of power failure or system lock-up.
综上所述，虽然目前对于电液复合式转向系统的研究有了一定的进展，但是整体方案还不是最优的，尚需要进一步设计优化，以实现系统部分电动化节能、更加集成的同时，不会带来成本、可靠性以及安全性问题。此外考虑到电液复合式转向系统存在两套独立机构，其能量管理策略与其结构总成参数间存在一定的耦合关系，而现有结构优化方法仅仅是进行系统结构的优化，而不考虑这种耦合关系，难以最大化系统的节能性能。因此在进行系统优化时有必要考虑所采用的的能量管理策略中的参数，进行多参数耦合优化，以实现能量管理策略和结构总成参数间的最佳匹配，保证系统必要要求的同时，最大化系统节能效果。To sum up, although the current research on the electro-hydraulic hybrid steering system has made some progress, the overall scheme is still not optimal, and further design and optimization are needed to achieve partial electrification, energy saving and more integration of the system. No cost, reliability, or safety issues. In addition, considering that there are two independent mechanisms in the electro-hydraulic hybrid steering system, there is a certain coupling relationship between its energy management strategy and its structural assembly parameters, and the existing structural optimization methods only optimize the system structure without considering this Coupling relationship, it is difficult to maximize the energy-saving performance of the system. Therefore, when performing system optimization, it is necessary to consider the parameters in the adopted energy management strategy, and conduct multi-parameter coupling optimization to achieve the best match between the energy management strategy and the structural assembly parameters, ensuring the necessary requirements of the system while maximizing system energy saving effect.
发明内容Contents of the invention
本发明所要解决的技术问题是针对背景技术的缺陷，提供一种电液集成式转向系统及其多参数耦合优化方法，以解决现有技术中存在的电液复合式转向系统设计方案难以兼得电动化节能、结构集成、安全可靠、成本高以及仅进行结构单独优化的问题。本发明采用将电动助力机构集成在原有液压系统转向器的底部、行星齿轮减速器替代原有的涡轮蜗杆减速器和保留原有的液压助力机构中机械转阀结构的设计方案，一方面电动和液压机构高度集成，可通过协调工作降低能耗，另一方面可以将路面信息实时反馈，给予驾驶员清晰的路感。此外，由于系统还具有多执行机构互为冗余、行星齿轮减速器消除了系统卡死隐患以及保留机械转阀结构故障率低等优势，且通过对系统进行多参数耦合优化，也可在保证成本、可靠性、路感的同时，最大化系统经济性。The technical problem to be solved by the present invention is to provide an electro-hydraulic integrated steering system and its multi-parameter coupling optimization method for the defects of the background technology, so as to solve the problem that the design scheme of the electro-hydraulic composite steering system in the prior art is difficult to have both Electrification and energy saving, structural integration, safety and reliability, high cost, and only the optimization of the structure alone. The present invention adopts the design scheme of integrating the electric booster mechanism at the bottom of the steering gear of the original hydraulic system, replacing the original worm gear reducer with the planetary gear reducer and retaining the mechanical rotary valve structure in the original hydraulic booster mechanism. The hydraulic mechanism is highly integrated, which can reduce energy consumption through coordinated work. On the other hand, it can feed back road surface information in real time, giving the driver a clear sense of the road. In addition, because the system also has the advantages of multi-actuator mutual redundancy, the planetary gear reducer eliminates the hidden danger of system jamming, and retains the low failure rate of the mechanical rotary valve structure, and through the multi-parameter coupling optimization of the system, it can also be guaranteed Maximize system economy while reducing cost, reliability, and road feel.
为达到上述目的，本发明采用的技术方案如下：In order to achieve the above object, the technical scheme adopted in the present invention is as follows:
本发明的一种电-液集成转向系统，包括：机械传动模块、电动助力模块、液压助力模块和控制模块；An electric-hydraulic integrated steering system of the present invention includes: a mechanical transmission module, an electric power boost module, a hydraulic power boost module and a control module;
所述机械传动模块包括：方向盘、转向轴、万向节、循环球转向器、转向摇臂、转向直拉杆、转向节臂、左转向节、左梯形臂、转向横拉杆、右梯形臂、右转向节、左车轮和右车轮；The mechanical transmission module includes: steering wheel, steering shaft, universal joint, recirculating ball steering gear, steering rocker arm, steering straight rod, steering knuckle arm, left steering knuckle, left trapezoidal arm, steering tie rod, right trapezoidal arm, right Steering knuckle, left and right wheels;
所述转向轴上端与所述方向盘相连，下端通过所述万向节与所述循环球转向器的上输入端连接；The upper end of the steering shaft is connected to the steering wheel, and the lower end is connected to the upper input end of the recirculating ball steering device through the universal joint;
所述转向摇臂的输入端与所述循环球转向器的输出端连接，输出端通过所述转向直拉杆与所述转向节臂相连；The input end of the steering rocker arm is connected to the output end of the recirculating ball steering gear, and the output end is connected to the steering knuckle arm through the steering straight rod;
所述左转向节与所述左车轮相连，其上固定有所述转向节臂和左梯形臂；The left steering knuckle is connected with the left wheel, on which the steering knuckle arm and the left trapezoidal arm are fixed;
所述转向横拉杆的两端分别与所述左梯形臂和右梯形臂相连；Both ends of the steering tie rod are respectively connected with the left trapezoidal arm and the right trapezoidal arm;
所述右转向节与所述右车轮相连，其上固定有所述右梯形臂；The right steering knuckle is connected with the right wheel, on which the right trapezoidal arm is fixed;
所述电动助力模块包括：助力电机、行星齿轮减速器和电磁制动块；The electric booster module includes: a booster motor, a planetary gear reducer and an electromagnetic brake block;
所述行星齿轮减速器包括太阳轮、行星轮、行星架和齿圈；The planetary gear reducer includes a sun gear, a planetary gear, a planet carrier and a ring gear;
所述太阳轮的输入端与所述助力电机的输出端固定连接，输出端与所述行星轮啮合；The input end of the sun gear is fixedly connected to the output end of the booster motor, and the output end meshes with the planetary gear;
所述齿轮外圈上压靠着所述电磁制动块，且不通电时处于压靠制动状态，其内圈与所述行星轮啮合；The outer ring of the gear presses against the electromagnetic brake block, and is in a pressing and braking state when no power is applied, and its inner ring meshes with the planetary wheel;
所述行星架的输入端与所述行星轮固定相连，其输出端与所述循环球转向器的下输入端固定相连；The input end of the planet carrier is fixedly connected with the planetary wheel, and its output end is fixedly connected with the lower input end of the recirculating ball diverter;
所述液压助力模块包括：动力缸、轴承、转向螺杆、转向螺母、齿扇、循环球、循环球导管、转向阀、卸荷阀、单向阀、限压阀、油壶、液压管路、齿轮泵和液压电机；The hydraulic booster module includes: a power cylinder, a bearing, a steering screw, a steering nut, a gear fan, a recirculating ball, a recirculating ball guide, a steering valve, an unloading valve, a one-way valve, a pressure limiting valve, an oil pot, a hydraulic pipeline, Gear pumps and hydraulic motors;
所述动力缸为所述循环球转向器的内腔；The power cylinder is the inner cavity of the recirculating ball diverter;
所述轴承位于所述动力缸内，并套装在所述转向螺杆的上下两端；The bearing is located in the power cylinder and is set on the upper and lower ends of the steering screw;
所述转向螺杆的上下输入端即为所述循环球转向器的上下输入端，其输 出端通过所述循环球与所述转向螺母啮合；The upper and lower input ends of the steering screw are the upper and lower input ends of the recirculating ball diverter, and its output end is engaged with the steering nut through the recirculating ball;
所述循环球导管安装在所述转向螺母上，用做循环球循环流动的通道；The circulating ball guide is installed on the steering nut and used as a channel for the circulating flow of the circulating ball;
所述齿扇的输入端与所述转向螺母上加工的齿条啮合，其输出端与所述转向摇臂相连；The input end of the gear fan meshes with the rack processed on the steering nut, and its output end is connected with the steering rocker arm;
所述卸荷阀安装在所述转向螺母内，用于当转向螺母移动至极限位置时平衡其两侧的压力；The unloading valve is installed in the steering nut and is used to balance the pressure on both sides of the steering nut when it moves to the limit position;
所述齿轮泵的输入端与所述液压电机的输出端相连，其进油口通过液压管路与所述油壶相连，出油口与所述转向阀相连；The input end of the gear pump is connected to the output end of the hydraulic motor, its oil inlet is connected to the oil pot through a hydraulic pipeline, and its oil outlet is connected to the steering valve;
所述油壶的回油口与所述转向阀通过液压管路相连，其出油口与所述齿轮泵通过液压管路相连；The oil return port of the oil pot is connected with the steering valve through a hydraulic pipeline, and its oil outlet is connected with the gear pump through a hydraulic pipeline;
所述限压阀和单向阀安装在用于连接齿轮泵出油口与转向阀的液压管路和用于连接转向阀和油壶回油口的液压管路之间，前者用于限制液压管路内液压油的压力，后者为了防止液压管路出现真空；The pressure limiting valve and the one-way valve are installed between the hydraulic pipeline used to connect the oil outlet of the gear pump and the steering valve and the hydraulic pipeline used to connect the steering valve and the oil return port of the oil pot. The former is used to limit the hydraulic pressure. The pressure of hydraulic oil in the pipeline, the latter is to prevent vacuum in the hydraulic pipeline;
所述控制模块包括：电子控制单元、方向盘转角传感器、转矩传感器、车速传感器；The control module includes: an electronic control unit, a steering wheel angle sensor, a torque sensor, and a vehicle speed sensor;
所述电子控制单元的输入端与所述方向盘转角传感器、转矩传感器、车速传感器电气相连，其输出端与所述助力电机、液压电机电气连接，转向时根据从各传感器得到的车辆转态参数，进行助力控制；The input end of the electronic control unit is electrically connected to the steering wheel angle sensor, torque sensor, and vehicle speed sensor, and its output end is electrically connected to the booster motor and hydraulic motor. , to carry out boost control;
所述方向盘转角传感器安装在方向盘上，用于获得车辆转向时的方向盘转角信号，并将方向盘转角信号传递到所述电子控制单元。The steering wheel angle sensor is installed on the steering wheel to obtain the steering wheel angle signal when the vehicle is turning, and transmit the steering wheel angle signal to the electronic control unit.
所述转矩传感器安装在所述转向轴上，用于获取转矩信号，并将转矩信号传递给所述电子控制单元；The torque sensor is installed on the steering shaft to obtain a torque signal and transmit the torque signal to the electronic control unit;
所述车速传感器安装在车辆上，用于将获得的车速信号传递到所述电子控制单元；The vehicle speed sensor is installed on the vehicle, and is used to transmit the obtained vehicle speed signal to the electronic control unit;
此外，本发明还提供了一种电-液集成转向系统的多参数耦合优化方法，基于上述系统，包含以下步骤：In addition, the present invention also provides a multi-parameter coupling optimization method for an electro-hydraulic integrated steering system, based on the above system, including the following steps:
(1)建立电-液集成转向系统的数学模型；(1) Establish the mathematical model of the electro-hydraulic integrated steering system;
(2)根据步骤(1)中建立的系统模型，建立转向系统优化目标；(2) according to the system model established in the step (1), establish the optimization target of the steering system;
(3)选取一种将在系统中应用的能量管理策略，预选可能会影响系统性能的能量管理策略和转向系统参数15个，分别对各参数取三个水平的值进行试验，即最大变动量、最小变动量和中间值，得到试验数据，分析各参数的灵敏度，选取对应的设计变量；(3) Select an energy management strategy to be applied in the system, pre-select 15 energy management strategies and steering system parameters that may affect system performance, and test each parameter at three levels, that is, the maximum variation , the minimum variation and the median value, get the test data, analyze the sensitivity of each parameter, and select the corresponding design variables;
(4)将步骤(3)中选择的设计变量，并确定各参数对应的约束条件，根据步骤(1)中的系统模型和步骤(2)中的优化目标，建立优化模型；(4) with the design variable selected in the step (3), and determine the constraint condition corresponding to each parameter, according to the system model in the step (1) and the optimization target in the step (2), set up the optimization model;
(5)基于步骤(4)中建立的优化模型，采用优化算法求解出最优的结构及能量管理策略参数；(5) Based on the optimization model established in step (4), an optimization algorithm is used to solve the optimal structure and energy management strategy parameters;
进一步地，所述步骤(1)中电-液集成转向系统数学模型建立步骤如下：Further, the steps for establishing the mathematical model of the electric-hydraulic integrated steering system in the step (1) are as follows:
(1.1)机械传动部分模型(1.1) Model of mechanical transmission part
方向盘与转向轴模型：Steering wheel and steering shaft model:
考虑转向盘转动惯量与粘性阻尼忽略其刚度，忽略库仑摩擦力，则其数学模型为：Considering the moment of inertia and viscous damping of the steering wheel, ignoring its stiffness and Coulomb friction, its mathematical model is:
Figure PCTCN2022092942-appb-000001
Figure PCTCN2022092942-appb-000001
T s＝K s(θ w-θ s)        (2) T s ＝K s (θ w -θ s ) (2)
式中，J w为方向盘的转动惯量；B w为方向盘的阻尼系数；K s为转矩传感器中扭杆刚度；θ w为方向盘转角；θ s为转向轴转角；T w为方向盘输入转矩T s为转矩传感器输出转矩。 In the formula, J w is the moment of inertia of the steering wheel; B w is the damping coefficient of the steering wheel; K s is the torsion bar stiffness in the torque sensor; θ w is the steering wheel angle; θ s is the steering shaft angle; T w is the input torque of the steering wheel T s is the output torque of the torque sensor.
循环球转向器模型：Recirculating ball diverter model:
Figure PCTCN2022092942-appb-000002
Figure PCTCN2022092942-appb-000002
式中，J g是转向螺杆与电动助力模块减速机构的等效转动惯量，B g是转向螺杆与减速机构的等效粘性阻尼系数，K w为转向轴刚度，θ g是转向螺杆转角，η g是转向螺杆进给效率，d g为转向螺杆的导程，T EPS为电动助力模块助力转矩，T p为转向阻力矩在齿扇上的等效力矩，r p为齿扇节圆半径，F HPS为液压助力模块所提供的助力，d r为等效到转向螺杆上的路面随机干扰力矩。 In the formula, J g is the equivalent moment of inertia of the steering screw and the reduction mechanism of the electric power booster module, B g is the equivalent viscous damping coefficient of the steering screw and the reduction mechanism, K w is the stiffness of the steering shaft, θ g is the rotation angle of the steering screw, η g is the feed efficiency of the steering screw, d g is the lead of the steering screw, T EPS is the power assist torque of the electric power assist module, T p is the equivalent torque of the steering resistance torque on the gear sector, and r p is the pitch circle radius of the gear sector , F HPS is the power boost provided by the hydraulic power booster module, and d r is the road surface random disturbance torque equivalent to the steering screw.
液压模块助力表示为：The power assist of the hydraulic module is expressed as:
F HPS＝A p(P A-P B)        (4) F HPS ＝A p (P A -P B ) (4)
式中，A p为液压缸活塞的有效面积，P A、P B分别表示液压缸两端压力。 In the formula, A p is the effective area of the piston of the hydraulic cylinder, and P A and P B represent the pressure at both ends of the hydraulic cylinder respectively.
(1.2)液压助力模块模型(1.2) Hydraulic booster module model
齿轮泵模型gear pump model
齿轮泵输入转矩：Gear pump input torque:
T hm＝qP s         (5) T hm =qP s (5)
式中，q为齿轮泵平均排量，P s为齿轮泵工作压强，T hm为齿轮泵输入转矩。 In the formula, q is the average displacement of the gear pump, P s is the working pressure of the gear pump, and T hm is the input torque of the gear pump.
齿轮泵工作时的压强表示为：The pressure when the gear pump is working is expressed as:
P s＝2πηT hm/q        (6) P s =2πηT hm /q (6)
式中，π为圆周率常数，η为液压泵机械效率。In the formula, π is the constant of pi, and η is the mechanical efficiency of the hydraulic pump.
齿轮泵工作时的平均排量表示为：The average displacement of the gear pump is expressed as:
q＝ζ2πm 2Zb        (7) q=ζ2πm 2 Zb (7)
式中，ζ为补偿系数，m为齿轮泵的齿轮模数，Z为齿轮泵的齿轮齿数，b为齿轮的齿宽，In the formula, ζ is the compensation coefficient, m is the gear modulus of the gear pump, Z is the number of teeth of the gear pump, b is the tooth width of the gear,
齿轮泵工作时的输出流量表示为：The output flow of the gear pump is expressed as:
Q＝qnη V＝2πkm 2Zbnη V        (8) Q＝qnη V ＝2πkm 2 Zbnη V (8)
式中，n为齿轮泵转速，η V为齿轮泵的容积效率，Q为齿轮泵输出流量。 In the formula, n is the speed of the gear pump, η V is the volumetric efficiency of the gear pump, and Q is the output flow of the gear pump.
液压电机模型hydraulic motor model
液压电机电气特性数学模型为：The mathematical model of the electrical characteristics of the hydraulic motor is:
Figure PCTCN2022092942-appb-000003
Figure PCTCN2022092942-appb-000003
式中，P h为液压电机功率，u h为液压电机电枢电压，i h为液压电机电枢电流，R h为液压电机的电枢电阻，L h为电枢电感，θ h为液压电机转角，K h为反电动势常数。 In the formula, P h is the hydraulic motor power, u h is the hydraulic motor armature voltage, i h is the hydraulic motor armature current, R h is the hydraulic motor armature resistance, L h is the armature inductance, θ h is the hydraulic motor K h is the counter electromotive force constant.
液压电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the hydraulic motor is:
Figure PCTCN2022092942-appb-000004
Figure PCTCN2022092942-appb-000004
式中，J h为液压电机转动惯量，θ h为液压电机转角，B h为液压电机轴阻尼系数，T h为液压电机电磁转矩，T hm为液压电机输出转矩。 In the formula, J h is the moment of inertia of the hydraulic motor, θ h is the rotation angle of the hydraulic motor, B h is the damping coefficient of the hydraulic motor shaft, T h is the electromagnetic torque of the hydraulic motor, and T hm is the output torque of the hydraulic motor.
液压电机电磁转矩方程为：The electromagnetic torque equation of the hydraulic motor is:
T h＝K hii h           (11) T h =K hi i h (11)
式中，K hi为液压电机转矩系数。 In the formula, K hi is the torque coefficient of the hydraulic motor.
转向阀模型Steering valve model
转向阀模型表示为：The steering valve model is expressed as:
Figure PCTCN2022092942-appb-000005
Figure PCTCN2022092942-appb-000005
式中，Q V为阀体的总进油流量，Q L1、Q L2分别为动力油缸的进出油流量。 In the formula, Q V is the total oil inlet flow of the valve body, Q L1 and Q L2 are the oil inlet and outlet flow of the power cylinder respectively.
转向阀各个阀口液压油流量与压力差的关系表示为：The relationship between the hydraulic oil flow rate and the pressure difference at each valve port of the steering valve is expressed as:
Figure PCTCN2022092942-appb-000006
Figure PCTCN2022092942-appb-000006
式中，Q i(i＝1,2,3,4)为流经阀口i的流量，C d为流量系数，ΔP i为第i个阀口的两侧压力差，ρ为液压油的密度，A i为第i个阀口的节流面积，阀的结构一般为对称设计，即A 1＝A 3，A 2＝A 4。 In the formula, Q i (i=1, 2, 3, 4) is the flow rate flowing through the valve port i, C d is the flow coefficient, ΔP i is the pressure difference between the two sides of the i-th valve port, and ρ is the pressure of the hydraulic oil Density, A i is the throttling area of the i-th valve port, and the structure of the valve is generally designed symmetrically, that is, A 1 =A 3 , A 2 =A 4 .
转向阀各个阀口的开口面积表示为：The opening area of each valve port of the steering valve is expressed as:
Figure PCTCN2022092942-appb-000007
Figure PCTCN2022092942-appb-000007
式中，θ g-θ l表示转向螺杆与转向阀之间产生的相对转角，θ l为转向阀转角，R为转向阀和转向螺杆的配合半径，W 1为转向阀切口的宽度，W 2为中位时转向阀口的预开间隙宽度，L 1为切口轴向长度，L 2为转向阀口的轴向长度。 In the formula, θ g - θ l represents the relative rotation angle between the steering screw and the steering valve, θ l is the steering valve rotation angle, R is the matching radius of the steering valve and the steering screw, W 1 is the width of the steering valve cutout, W 2 is the pre-opening gap width of the steering valve port in the neutral position, L 1 is the axial length of the cutout, and L 2 is the axial length of the steering valve port.
(1.3)电动助力模块模型(1.3) Electric power booster module model
助力电机电气特性数学模型为：The mathematical model of the electrical characteristics of the booster motor is:
Figure PCTCN2022092942-appb-000008
Figure PCTCN2022092942-appb-000008
式中，P e为助力电机功率，u e为助力电机电枢电压，i e为助力电机电枢电流，R e为助力电机的电枢电阻，L e为电枢电感，θ e为助力电机转角，K e为反电动势常数。 In the formula, P e is the power of the booster motor, u e is the armature voltage of the booster motor, i e is the armature current of the booster motor, R e is the armature resistance of the booster motor, L e is the armature inductance, and θ e is the booster motor Rotation angle, K e is the counter electromotive force constant.
助力电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the booster motor is:
Figure PCTCN2022092942-appb-000009
Figure PCTCN2022092942-appb-000009
式中，J e为助力电机转动惯量，θ e为助力电机转角，B e为助力电机轴阻尼系数，T e为助力电机电磁转矩，T em为助力电机输出转矩。 In the formula, J e is the moment of inertia of the booster motor, θ e is the rotation angle of the booster motor, Be is the damping coefficient of the booster motor shaft, T e is the electromagnetic torque of the booster motor, and T em is the output torque of the booster motor.
助力电机电磁转矩方程为：The electromagnetic torque equation of the booster motor is:
T e＝K eii e           (17) T e =K ei i e (17)
式中，K ei为助力电机转矩系数。 In the formula, K ei is the torque coefficient of the booster motor.
电动助力模块所提供的助力T EPS表达式为： The power assist T EPS expression provided by the electric power assist module is:
T EPS＝T emG star          (18) T EPS = T em G star (18)
式中，G star是行星齿轮减速器的减速比。 In the formula, G star is the reduction ratio of the planetary gear reducer.
进一步地，所述步骤(2)中的优化目标为：Further, the optimization objective in the step (2) is:
(2.1)转向路感优化目标f1：(2.1) Steering road feeling optimization target f1:
Figure PCTCN2022092942-appb-000010
Figure PCTCN2022092942-appb-000010
式中，ω为系统频率，ω0＝40Hz为截止频率，j为虚数单位，X1、Y1、Z1分别为等效转动惯量、阻尼和刚度系数。In the formula, ω is the system frequency, ω0=40Hz is the cut-off frequency, j is the imaginary number unit, X1, Y1, Z1 are the equivalent moment of inertia, damping and stiffness coefficient respectively.
(2.2)转向灵敏度优化目标f2：(2.2) Steering sensitivity optimization target f2:
Figure PCTCN2022092942-appb-000011
Figure PCTCN2022092942-appb-000011
式中，Ai(i＝0,1,2,3)为传递函数分子系数，Qi(i＝0,1,2,3,4,5)为传递函数分母系数。In the formula, Ai (i=0,1,2,3) is the numerator coefficient of the transfer function, Qi (i=0,1,2,3,4,5) is the denominator coefficient of the transfer function.
(2.3)转向能耗优化目标f3：(2.3) Turn to the energy consumption optimization target f3:
Figure PCTCN2022092942-appb-000012
Figure PCTCN2022092942-appb-000012
式中，T n为转向需求转矩，n e为助力电机转速 In the formula, T n is the steering demand torque, n e is the speed of the assist motor
(2.4)系统成本优化目标：(2.4) System cost optimization objective:
f 4＝C(P e,P h,G star,d g,d,r p)         (22) f 4 ＝C(P e ,P h ,G star ,d g ,d,r p ) (22)
进一步地，所述步骤(3)中灵敏度分析步骤为：Further, the sensitivity analysis step in the step (3) is:
(3.1)分别对15个参数对转向路感目标进行极差分析，得到所选取的八个系统参数对转向路感目标的灵敏度大小的顺序，确定其对应的设计变量参数；(3.1) Carry out range analysis to 15 parameters respectively to steering sense target, obtain the order of the sensitivity of the eight selected system parameters to steering sense target, determine its corresponding design variable parameter;
(3.2)分别将15个系统参数对转向灵敏度目标进行极差分析，得到所选取的八个系统参数对转向灵敏度目标的灵敏度大小的顺序，确定其对应的设计变量参数；(3.2) 15 system parameters are carried out range analysis to steering sensitivity target respectively, obtain the order of the sensitivity size of eight selected system parameters to steering sensitivity target, determine its corresponding design variable parameter;
(3.3)分别将15个系统参数对转向能耗目标进行极差分析，得到所选取的八个系统参数对转向能耗目标的灵敏度大小的顺序，确定其对应的设计变量参数；(3.3) Carry out range analysis on 15 system parameters to the steering energy consumption target, obtain the order of the sensitivity of the selected eight system parameters to the steering energy consumption target, and determine its corresponding design variable parameters;
(3.4)分别将15个系统参数对系统成本目标进行极差分析，得到所选取的八个系统参数对系统成本目标的灵敏度大小的顺序，确定其对应的设计变量参数；(3.4) Perform range analysis on 15 system parameters to the system cost target, obtain the order of the sensitivity of the selected eight system parameters to the system cost target, and determine the corresponding design variable parameters;
进一步地，所述步骤(3)中选取的能量管理策略为基于模糊规则的能量管理策略，所述最终的设计变量为模糊规则中电动助力模块输出转矩的隶属度函数节点Oe，液压助力模块的隶属度函数节点Oh，需求转矩的隶属度函数节点On，液压电机功率Ph，助力电机功率Pe，行星齿轮减速比Gstar，转向螺杆导程dg，齿扇节圆半径rp，齿轮泵直径d；Further, the energy management strategy selected in the step (3) is an energy management strategy based on fuzzy rules, and the final design variable is the membership function node Oe of the output torque of the electric power booster module in the fuzzy rules, and the hydraulic power booster module The membership function node Oh of the required torque, the membership function node On of the required torque, the power of the hydraulic motor Ph, the power of the booster motor Pe, the reduction ratio of the planetary gear Gstar, the lead of the steering screw dg, the pitch circle radius rp of the tooth sector, and the diameter of the gear pump d ;
进一步地，所述步骤(4)中建立的优化模型为：Further, the optimization model established in the step (4) is:
Figure PCTCN2022092942-appb-000013
Figure PCTCN2022092942-appb-000013
式中，f 1(X)为转向路感优化目标，f 2(X)为转向灵敏度指标优化目标，f 3(X)为转向能耗优化目标，f 4(X)为系统成本优化目标。 In the formula, f 1 (X) is the optimization target of steering road feeling, f 2 (X) is the optimization target of steering sensitivity index, f 3 (X) is the optimization target of steering energy consumption, and f 4 (X) is the optimization target of system cost.
进一步地，所述步骤(5)中所用的优化方法选用多目标粒子群优化算法，具体步骤如下：Further, the optimization method used in the step (5) selects multi-objective particle swarm optimization algorithm, and the specific steps are as follows:
(5.1)初始化粒子种群m，随机生成初始位置X0和初始速度V0，粒子的初始个体最优位置Pbest＝X0：(5.1) Initialize the particle population m, randomly generate the initial position X0 and the initial velocity V0, and the initial individual optimal position of the particle Pbest=X0:
Figure PCTCN2022092942-appb-000014
Figure PCTCN2022092942-appb-000014
外部档案Ns为空，迭代次数设为M，迭代过程中第i个粒子的位置和速度向量表示为：The external file Ns is empty, the number of iterations is set to M, and the position and velocity vectors of the i-th particle during the iteration process are expressed as:
Figure PCTCN2022092942-appb-000015
Figure PCTCN2022092942-appb-000015
式中，PbestK(K＝X)为设计变量对应的最优位置分量，XiK(K＝X)为各设计变量对应的位置分量，ViK(K＝X)为各设计变量对应的速度分量。In the formula, PbestK(K=X) is the optimal position component corresponding to the design variable, XiK(K=X) is the position component corresponding to each design variable, and ViK(K=X) is the velocity component corresponding to each design variable.
(5.2)计算每个粒子的目标函数，将非支配解存入外部档案中；(5.2) Calculate the objective function of each particle, and store the non-dominated solution in an external file;
(5.3)计算外部档案中每个个体距粒子中心Xcenter的欧式距离：(5.3) Calculate the Euclidean distance from each individual in the external file to the particle center Xcenter:
d ij＝||X i-X center||          (26) d ij ＝||X i -X center || (26)
按照轮盘赌选择方法，随机选择外部档案中的个体作为粒子的历史全局最优位置Gbest：According to the roulette selection method, the individual in the external archives is randomly selected as the historical global optimal position Gbest of the particle:
Figure PCTCN2022092942-appb-000016
Figure PCTCN2022092942-appb-000016
(5.4)根据式(27)更新粒子的位置X和速度V，同时更新粒子的Pbest，并用当前粒子群中的非支配解更新外部档案Ns：(5.4) Update the position X and velocity V of the particle according to formula (27), update the Pbest of the particle at the same time, and update the external file Ns with the non-dominated solution in the current particle swarm:
Figure PCTCN2022092942-appb-000017
Figure PCTCN2022092942-appb-000017
式中，c1和c2为学习因子，r1和r2为取值在0-1之间的随机数，□t为时间间隔。In the formula, c1 and c2 are learning factors, r1 and r2 are random numbers between 0 and 1, and □t is the time interval.
(5.5)判断外部档案中的个体数目是否超过给定的最大容量，如果超过则删除距离中心最小的个体，否则进行下一步；(5.5) Determine whether the number of individuals in the external file exceeds the given maximum capacity, if so, delete the individual with the smallest distance from the center, otherwise proceed to the next step;
(5.6)从外部档案中随机选择部分个体进行混沌变异，搜索附近区域的非支配解；(5.6) Randomly select some individuals from the external archives for chaotic mutation, and search for non-dominated solutions in nearby areas;
(5.7)若满足结束条件，则停止搜索，从外部档案中输出Pareto最优解集，否则转步骤(5.3)再循环直至结束输出Pareto最优解集；(5.7) If the end condition is satisfied, then stop the search, and output the Pareto optimal solution set from the external file, otherwise turn to step (5.3) and recycle until the end to output the Pareto optimal solution set;
(5.8)设置各目标函数的优先级权重w1、w2、w3、w4，并根据目标权重从步骤(5.7)中求解的Pareto解集中选取最终的优化结果。(5.8) Set the priority weights w1, w2, w3, w4 of each objective function, and select the final optimization result from the Pareto solution set solved in step (5.7) according to the objective weights.
本发明采用以上技术方案与现有技术相比，具有以下有益效果：Compared with the prior art, the present invention has the following beneficial effects by adopting the above technical scheme:
本发明采用通过将电动助力机构集成在原有液压系统转向器的底部、采用行星齿轮减速器替代原有的涡轮蜗杆减速器以及保留原有的液压助力机构中机械转阀结构等结构方案不仅实现了转向系统助力机构的高度集成，也消除了管柱加装方案下的路感隔绝问题，提供驾驶员良好的路感，同时系统可在电动机构故障下向电磁制动块中通电断开对齿轮的限制，在减速器中加入一个自由度，实现电动助力部分的故障随动，消除了系统卡死的隐患。The present invention adopts the structure schemes such as integrating the electric booster mechanism at the bottom of the steering gear of the original hydraulic system, replacing the original worm gear reducer with a planetary gear reducer, and retaining the mechanical rotary valve structure in the original hydraulic booster mechanism. The high integration of the steering system assist mechanism also eliminates the road sense isolation problem under the pipe column installation scheme, providing the driver with a good road sense. At the same time, the system can energize the electromagnetic brake block and disconnect the pair of gears when the electric mechanism fails. A degree of freedom is added to the reducer to realize the fault follow-up of the electric power assist part, eliminating the hidden danger of system jamming.
本发明提出的系统还可以通过多执行机构互为冗余和保留机械转阀结构进一步提高转向系统的可靠性。The system proposed by the present invention can further improve the reliability of the steering system through mutual redundancy of multiple actuators and retaining the structure of the mechanical rotary valve.
本发明通过对系统的结构和功率优化，也可实现在不增加系统总成本的同时提升系统性能，技术优势大，可行性高。By optimizing the structure and power of the system, the present invention can also improve the system performance without increasing the total cost of the system, and has great technical advantages and high feasibility.
本发明提出的多参数耦合优化方法，可以实现对结构总成参数和能量管理策略的共同优化，使得能量管理策略和结构总成参数相互匹配，最大化了系统的经济性。The multi-parameter coupling optimization method proposed by the present invention can realize the joint optimization of the structural assembly parameters and the energy management strategy, so that the energy management strategy and the structural assembly parameters match each other, maximizing the economy of the system.
附图说明Description of drawings
图1为本发明的电-液集成转向系统示意图；Fig. 1 is the electric-hydraulic integrated steering system schematic diagram of the present invention;
图2为本发明的行星齿轮减速器示意图；Fig. 2 is a schematic diagram of a planetary gear reducer of the present invention;
图3为本发明的电-液集成转向系统结构优化方法流程图；Fig. 3 is a flow chart of the structure optimization method of the electric-hydraulic integrated steering system of the present invention;
图4为本发明的优化算法流程图；Fig. 4 is the optimization algorithm flowchart of the present invention;
图中，1-方向盘，2-方向盘转角传感器，3-转矩传感器，4-转向轴，5-万向节，6-轴承，7-齿扇，8-转向摇臂，9-转向直拉杆，10-左车轮，11-左转向节，12-左梯形臂，13-转向节臂，14-转向横拉杆，15-电磁制动块，16-转向阀，17-助力电机，18-行星齿轮减速器，19-循环球，20-卸荷阀，21-电子控制单元，22-齿轮泵，23-车速传感器，24-右梯形臂，25-右转向节，26-右车轮，27-液压电机，28-循环球导管，29-转向螺母，30-单向阀，31-液压管路，32-限压阀，33-油壶，34-动力缸，35-循环球转向器，36-转向螺杆，37-齿圈，38-太阳轮，39-行星轮，40-行星架。In the figure, 1-steering wheel, 2-steering wheel angle sensor, 3-torque sensor, 4-steering shaft, 5-universal joint, 6-bearing, 7-tooth fan, 8-steering rocker arm, 9-steering straight rod , 10-left wheel, 11-left steering knuckle, 12-left trapezoidal arm, 13-steering knuckle arm, 14-steering tie rod, 15-electromagnetic brake block, 16-steering valve, 17-assist motor, 18-planet Gear reducer, 19-circulating ball, 20-unloading valve, 21-electronic control unit, 22-gear pump, 23-vehicle speed sensor, 24-right trapezoidal arm, 25-right steering knuckle, 26-right wheel, 27- Hydraulic motor, 28-circulating ball guide, 29-steering nut, 30-one-way valve, 31-hydraulic pipeline, 32-pressure limiting valve, 33-oil pot, 34-power cylinder, 35-circulating ball steering gear, 36 -Steering screw, 37-ring gear, 38-sun gear, 39-planetary gear, 40-planet carrier.
本发明的较佳实施方式Preferred Embodiments of the Invention
下面结合附图对本发明的技术方案做进一步的详细说明：Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:
本发明可以以许多不同的形式实现，而不应当认为限于这里所述的实施例。相反，提供这些实施例以便使本公开透彻且完整，并且将向本领域技术人员充分表达本发明的范围。This invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
具体实施1：Specific implementation 1:
电-液集成转向系统数学模型建立步骤如下：The steps to establish the mathematical model of the electro-hydraulic integrated steering system are as follows:
(1.1)机械传动部分模型(1.1) Model of mechanical transmission part
a.方向盘与转向轴模型：a. Steering wheel and steering shaft model:
考虑转向盘转动惯量与粘性阻尼忽略其刚度，忽略库仑摩擦力，则其数学模型为：Considering the moment of inertia and viscous damping of the steering wheel, ignoring its stiffness and Coulomb friction, its mathematical model is:
Figure PCTCN2022092942-appb-000018
Figure PCTCN2022092942-appb-000018
T s＝K s(θ w-θ s)       (2) T s ＝K s (θ w -θ s ) (2)
式中，J w为方向盘的转动惯量；B w为方向盘的阻尼系数；K s为转矩传感器中扭杆刚度；θ w为方向盘转角；θ s为转向轴转角；T w为方向盘输入转矩T s为 转矩传感器输出转矩。 In the formula, J w is the moment of inertia of the steering wheel; B w is the damping coefficient of the steering wheel; K s is the torsion bar stiffness in the torque sensor; θ w is the steering wheel angle; θ s is the steering shaft angle; T w is the input torque of the steering wheel T s is the output torque of the torque sensor.
b.循环球转向器模型：b. Recirculating ball diverter model:
Figure PCTCN2022092942-appb-000019
Figure PCTCN2022092942-appb-000019
式中，J g是转向螺杆与电动助力模块减速机构的等效转动惯量，B g是转向螺杆与减速机构的等效粘性阻尼系数，K w为转向轴刚度，θ g是转向螺杆转角，η g是转向螺杆进给效率，d g为转向螺杆的导程，T EPS为电动助力模块助力转矩，T p为转向阻力矩在齿扇上的等效力矩，r p为齿扇节圆半径，F HPS为液压助力模块所提供的助力，d r为等效到转向螺杆上的路面随机干扰力矩。 In the formula, J g is the equivalent moment of inertia of the steering screw and the reduction mechanism of the electric power booster module, B g is the equivalent viscous damping coefficient of the steering screw and the reduction mechanism, K w is the stiffness of the steering shaft, θ g is the rotation angle of the steering screw, η g is the feed efficiency of the steering screw, d g is the lead of the steering screw, T EPS is the power assist torque of the electric power assist module, T p is the equivalent torque of the steering resistance torque on the gear sector, and r p is the pitch circle radius of the gear sector , F HPS is the power boost provided by the hydraulic power booster module, and d r is the road surface random disturbance torque equivalent to the steering screw.
液压模块助力表示为：The power assist of the hydraulic module is expressed as:
F HPS＝A p(P A-P B)         (4) F HPS ＝A p (P A -P B ) (4)
式中，A p为液压缸活塞的有效面积，P A、P B分别表示液压缸两端压力。 In the formula, A p is the effective area of the piston of the hydraulic cylinder, and P A and P B represent the pressure at both ends of the hydraulic cylinder respectively.
(1.2)液压助力模块模型(1.2) Hydraulic booster module model
a.齿轮泵模型a. Gear pump model
齿轮泵输入转矩：Gear pump input torque:
T hm＝qP s          (5) T hm =qP s (5)
式中，q为齿轮泵平均排量，P s为齿轮泵工作压强，T hm为齿轮泵输入转矩。 In the formula, q is the average displacement of the gear pump, P s is the working pressure of the gear pump, and T hm is the input torque of the gear pump.
齿轮泵工作时的压强表示为：The pressure when the gear pump is working is expressed as:
P s＝2πηT hm/q          (6) P s =2πηT hm /q (6)
式中，π为圆周率常数，η为液压泵机械效率。In the formula, π is the constant of pi, and η is the mechanical efficiency of the hydraulic pump.
齿轮泵工作时的平均排量表示为：The average displacement of the gear pump is expressed as:
q＝ζ2πm 2Zb        (7) q=ζ2πm 2 Zb (7)
式中，ζ为补偿系数，m为齿轮泵的齿轮模数，Z为齿轮泵的齿轮齿数，b为齿轮的齿宽，In the formula, ζ is the compensation coefficient, m is the gear modulus of the gear pump, Z is the number of teeth of the gear pump, b is the tooth width of the gear,
齿轮泵工作时的输出流量表示为：The output flow of the gear pump is expressed as:
Q＝qnη V＝2πkm 2Zbnη V        (8) Q＝qnη V ＝2πkm 2 Zbnη V (8)
式中，n为齿轮泵转速，η V为齿轮泵的容积效率，Q为齿轮泵输出流量。 In the formula, n is the speed of the gear pump, η V is the volumetric efficiency of the gear pump, and Q is the output flow of the gear pump.
b.液压电机模型b. Hydraulic motor model
液压电机电气特性数学模型为：The mathematical model of the electrical characteristics of the hydraulic motor is:
Figure PCTCN2022092942-appb-000020
Figure PCTCN2022092942-appb-000020
式中，P h为液压电机功率，u h为液压电机电枢电压，i h为液压电机电枢电流，R h为液压电机的电枢电阻，L h为电枢电感，θ h为液压电机转角，K h为反电动势常数。 In the formula, P h is the hydraulic motor power, u h is the hydraulic motor armature voltage, i h is the hydraulic motor armature current, R h is the hydraulic motor armature resistance, L h is the armature inductance, θ h is the hydraulic motor K h is the counter electromotive force constant.
液压电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the hydraulic motor is:
Figure PCTCN2022092942-appb-000021
Figure PCTCN2022092942-appb-000021
式中，J h为液压电机转动惯量，θ h为液压电机转角，B h为液压电机轴阻尼系数，T h为液压电机电磁转矩，T hm为液压电机输出转矩。 In the formula, J h is the moment of inertia of the hydraulic motor, θ h is the rotation angle of the hydraulic motor, B h is the damping coefficient of the hydraulic motor shaft, T h is the electromagnetic torque of the hydraulic motor, and T hm is the output torque of the hydraulic motor.
液压电机电磁转矩方程为：The electromagnetic torque equation of the hydraulic motor is:
T h＝K hii h          (11) T h =K hi i h (11)
式中，K hi为液压电机转矩系数。 In the formula, K hi is the torque coefficient of the hydraulic motor.
c.转向阀模型c. Steering valve model
转向阀模型表示为：The steering valve model is expressed as:
Figure PCTCN2022092942-appb-000022
Figure PCTCN2022092942-appb-000022
式中，Q V为阀体的总进油流量，Q L1、Q L2分别为动力油缸的进出油流量。 In the formula, Q V is the total oil inlet flow of the valve body, Q L1 and Q L2 are the oil inlet and outlet flow of the power cylinder respectively.
转向阀各个阀口液压油流量与压力差的关系表示为：The relationship between the hydraulic oil flow rate and the pressure difference at each valve port of the steering valve is expressed as:
Figure PCTCN2022092942-appb-000023
Figure PCTCN2022092942-appb-000023
式中，Q i(i＝1,2,3,4)为流经阀口i的流量，C d为流量系数，ΔP i为第i个阀口的两侧压力差，ρ为液压油的密度，A i为第i个阀口的节流面积，阀的结构一般为对称设计，即A 1＝A 3，A 2＝A 4。 In the formula, Q i (i=1, 2, 3, 4) is the flow rate flowing through the valve port i, C d is the flow coefficient, ΔP i is the pressure difference between the two sides of the i-th valve port, and ρ is the pressure of the hydraulic oil Density, A i is the throttling area of the i-th valve port, and the structure of the valve is generally designed symmetrically, that is, A 1 =A 3 , A 2 =A 4 .
转向阀各个阀口的开口面积表示为：The opening area of each valve port of the steering valve is expressed as:
Figure PCTCN2022092942-appb-000024
Figure PCTCN2022092942-appb-000024
式中，θ g-θ l表示转向螺杆与转向阀之间产生的相对转角，θ l为转向阀转角，R为转向阀和转向螺杆的配合半径，W 1为转向阀切口的宽度，W 2为中位时转向阀口的预开间隙宽度，L 1为切口轴向长度，L 2为转向阀口的轴向长度。 In the formula, θ g - θ l represents the relative rotation angle between the steering screw and the steering valve, θ l is the steering valve rotation angle, R is the matching radius of the steering valve and the steering screw, W 1 is the width of the steering valve cutout, W 2 is the pre-opening gap width of the steering valve port in the neutral position, L 1 is the axial length of the cutout, and L 2 is the axial length of the steering valve port.
(1.3)电动助力模块模型(1.3) Electric power booster module model
助力电机电气特性数学模型为：The mathematical model of the electrical characteristics of the booster motor is:
Figure PCTCN2022092942-appb-000025
Figure PCTCN2022092942-appb-000025
式中，P e为助力电机功率，u e为助力电机电枢电压，i e为助力电机电枢电流，R e为助力电机的电枢电阻，L e为电枢电感，θ e为助力电机转角，K e为反电动势常数。 In the formula, P e is the power of the booster motor, u e is the armature voltage of the booster motor, i e is the armature current of the booster motor, R e is the armature resistance of the booster motor, L e is the armature inductance, and θ e is the booster motor Rotation angle, K e is the counter electromotive force constant.
助力电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the booster motor is:
Figure PCTCN2022092942-appb-000026
Figure PCTCN2022092942-appb-000026
式中，J e为助力电机转动惯量，θ e为助力电机转角，B e为助力电机轴阻尼系数，T e为助力电机电磁转矩，T em为助力电机输出转矩。 In the formula, J e is the moment of inertia of the booster motor, θ e is the rotation angle of the booster motor, Be is the damping coefficient of the booster motor shaft, T e is the electromagnetic torque of the booster motor, and T em is the output torque of the booster motor.
助力电机电磁转矩方程为：The electromagnetic torque equation of the booster motor is:
T e＝K eii e            (17) T e =K ei i e (17)
式中，K ei为助力电机转矩系数。 In the formula, K ei is the torque coefficient of the booster motor.
电动助力模块所提供的助力T EPS表达式为： The power assist T EPS expression provided by the electric power assist module is:
T EPS＝T emG star         (18) T EPS = T em G star (18)
式中，G star是行星齿轮减速器的减速比。 In the formula, G star is the reduction ratio of the planetary gear reducer.
具体实施2：Specific implementation 2:
建立转向系统优化目标为：The objective of establishing steering system optimization is:
(2.1)转向路感优化目标f1：(2.1) Steering road feeling optimization target f1:
Figure PCTCN2022092942-appb-000027
Figure PCTCN2022092942-appb-000027
式中，ω为系统频率，ω0＝40Hz为截止频率，j为虚数单位，X1、Y1、Z1分别为等效转动惯量、阻尼和刚度系数。In the formula, ω is the system frequency, ω0=40Hz is the cut-off frequency, j is the imaginary number unit, X1, Y1, Z1 are the equivalent moment of inertia, damping and stiffness coefficient respectively.
(2.2)转向灵敏度优化目标f2：(2.2) Steering sensitivity optimization target f2:
Figure PCTCN2022092942-appb-000028
Figure PCTCN2022092942-appb-000028
式中，Ai(i＝0,1,2,3)为传递函数分子系数，Qi(i＝0,1,2,3,4,5)为传递函数分母系数。In the formula, Ai (i=0,1,2,3) is the numerator coefficient of the transfer function, Qi (i=0,1,2,3,4,5) is the denominator coefficient of the transfer function.
(2.3)转向能耗优化目标f3：(2.3) Turn to the energy consumption optimization target f3:
Figure PCTCN2022092942-appb-000029
Figure PCTCN2022092942-appb-000029
式中，T n为转向需求转矩，n e为助力电机转速 In the formula, T n is the steering demand torque, n e is the speed of the assist motor
(2.4)系统成本优化目标：(2.4) System cost optimization objective:
f 4＝C(P e,P h,G star,d g,d,r p)         (22) f 4 ＝C(P e ,P h ,G star ,d g ,d,r p ) (22)
具体实施3：Specific implementation 3:
优化方法选用多目标粒子群优化算法，具体步骤如下：The optimization method uses the multi-objective particle swarm optimization algorithm, and the specific steps are as follows:
(3.1)初始化粒子种群m，随机生成初始位置X0和初始速度V0，粒子 的初始个体最优位置Pbest＝X0：(3.1) Initialize the particle population m, randomly generate the initial position X0 and initial velocity V0, and the initial individual best position Pbest=X0 of the particle:
Figure PCTCN2022092942-appb-000030
Figure PCTCN2022092942-appb-000030
外部档案Ns为空，迭代次数设为M，迭代过程中第i个粒子的位置和速度向量表示为：The external file Ns is empty, the number of iterations is set to M, and the position and velocity vectors of the i-th particle during the iteration process are expressed as:
Figure PCTCN2022092942-appb-000031
Figure PCTCN2022092942-appb-000031
式中，PbestK(K＝X)为设计变量对应的最优位置分量，XiK(K＝X)为各设计变量对应的位置分量，ViK(K＝X)为各设计变量对应的速度分量。In the formula, PbestK(K=X) is the optimal position component corresponding to the design variable, XiK(K=X) is the position component corresponding to each design variable, and ViK(K=X) is the velocity component corresponding to each design variable.
(3.2)计算每个粒子的目标函数，将非支配解存入外部档案中；(3.2) Calculate the objective function of each particle, and store the non-dominated solution in an external file;
(3.3)计算外部档案中每个个体距粒子中心Xcenter的欧式距离：(3.3) Calculate the Euclidean distance from each individual in the external file to the particle center Xcenter:
d ij＝||X i-X center||          (25) d ij ＝||X i -X center || (25)
按照轮盘赌选择方法，随机选择外部档案中的个体作为粒子的历史全局最优位置Gbest：According to the roulette selection method, the individual in the external archives is randomly selected as the historical global optimal position Gbest of the particle:
Figure PCTCN2022092942-appb-000032
Figure PCTCN2022092942-appb-000032
(3.4)根据式(26)更新粒子的位置X和速度V，同时更新粒子的Pbest，并用当前粒子群中的非支配解更新外部档案Ns：(3.4) Update the position X and velocity V of the particle according to formula (26), update the Pbest of the particle at the same time, and update the external file Ns with the non-dominated solution in the current particle swarm:
Figure PCTCN2022092942-appb-000033
Figure PCTCN2022092942-appb-000033
式中，c1和c2为学习因子，r1和r2为取值在0-1之间的随机数，□t为时间间隔。In the formula, c1 and c2 are learning factors, r1 and r2 are random numbers between 0 and 1, and □t is the time interval.
(3.5)判断外部档案中的个体数目是否超过给定的最大容量，如果超过则删除距离中心最小的个体，否则进行下一步；(3.5) Determine whether the number of individuals in the external file exceeds the given maximum capacity, if so, delete the individual with the smallest distance from the center, otherwise proceed to the next step;
(3.6)从外部档案中随机选择部分个体进行混沌变异，搜索附近区域的非支配解；(3.6) Randomly select some individuals from the external archives for chaotic mutation, and search for non-dominated solutions in nearby areas;
(3.7)若满足结束条件，则停止搜索，从外部档案中输出Pareto最优解集，否则转步骤(3.3)再循环直至结束输出Pareto最优解集；(3.7) If the end condition is satisfied, then stop the search, and output the Pareto optimal solution set from the external file, otherwise turn to step (3.3) and recycle until the end to output the Pareto optimal solution set;
(3.8)设置各目标函数的优先级权重w1、w2、w3、w4，并根据目标权重从步骤(3.7)中求解的Pareto解集中选取最终的优化结果。(3.8) Set the priority weights w1, w2, w3, w4 of each objective function, and select the final optimization result from the Pareto solution set solved in step (3.7) according to the objective weights.
以上所述的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施方式而已，并不用于限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

  1. 一种电液集成式转向系统及其多参数耦合优化方法，其特征在于，具体包括：机械传动模块、电动助力模块、液压助力模块和控制模块；An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method, characterized in that it specifically includes: a mechanical transmission module, an electric power assist module, a hydraulic power assist module and a control module;
    所述机械传动模块包括：方向盘、转向轴、万向节、循环球转向器、转向摇臂、转向直拉杆、转向节臂、左转向节、左梯形臂、转向横拉杆、右梯形臂、右转向节、左车轮和右车轮；The mechanical transmission module includes: steering wheel, steering shaft, universal joint, recirculating ball steering gear, steering rocker arm, steering straight rod, steering knuckle arm, left steering knuckle, left trapezoidal arm, steering tie rod, right trapezoidal arm, right Steering knuckle, left and right wheels;
    所述转向轴上端与所述方向盘相连，下端通过所述万向节与所述循环球转向器的上输入端连接；The upper end of the steering shaft is connected to the steering wheel, and the lower end is connected to the upper input end of the recirculating ball steering device through the universal joint;
    所述转向摇臂的输入端与所述循环球转向器的输出端连接，输出端通过所述转向直拉杆与所述转向节臂相连；The input end of the steering rocker arm is connected to the output end of the recirculating ball steering gear, and the output end is connected to the steering knuckle arm through the steering straight rod;
    所述左转向节与所述左车轮相连，其上固定有所述转向节臂和左梯形臂；The left steering knuckle is connected with the left wheel, on which the steering knuckle arm and the left trapezoidal arm are fixed;
    所述转向横拉杆的两端分别与所述左梯形臂和右梯形臂相连；Both ends of the steering tie rod are respectively connected with the left trapezoidal arm and the right trapezoidal arm;
    所述右转向节与所述右车轮相连，其上固定有所述右梯形臂；The right steering knuckle is connected with the right wheel, on which the right trapezoidal arm is fixed;
    所述电动助力模块包括：助力电机、行星齿轮减速器和电磁制动块；The electric booster module includes: a booster motor, a planetary gear reducer and an electromagnetic brake block;
    所述行星齿轮减速器包括太阳轮、行星轮、行星架和齿圈；The planetary gear reducer includes a sun gear, a planetary gear, a planet carrier and a ring gear;
    所述太阳轮的输入端与所述助力电机的输出端固定连接，输出端与所述行星轮啮合；The input end of the sun gear is fixedly connected to the output end of the booster motor, and the output end meshes with the planetary gear;
    所述齿轮外圈上压靠着所述电磁制动块，且不通电时处于压靠制动状态，其内圈与所述行星轮啮合；The outer ring of the gear presses against the electromagnetic brake block, and is in a pressing and braking state when no power is applied, and its inner ring meshes with the planetary wheel;
    所述行星架的输入端与所述行星轮固定相连，其输出端与所述循环球转向器的下输入端固定相连；The input end of the planet carrier is fixedly connected with the planetary wheel, and its output end is fixedly connected with the lower input end of the recirculating ball diverter;
    所述液压助力模块包括：动力缸、轴承、转向螺杆、转向螺母、齿扇、循环球、循环球导管、转向阀、卸荷阀、单向阀、限压阀、油壶、液压管路、齿轮泵和液压电机；The hydraulic booster module includes: a power cylinder, a bearing, a steering screw, a steering nut, a gear fan, a recirculating ball, a recirculating ball guide, a steering valve, an unloading valve, a one-way valve, a pressure limiting valve, an oil pot, a hydraulic pipeline, Gear pumps and hydraulic motors;
    所述动力缸为所述循环球转向器的内腔；The power cylinder is the inner cavity of the recirculating ball diverter;
    所述轴承位于所述动力缸内，并套装在所述转向螺杆的上下两端；The bearing is located in the power cylinder and is set on the upper and lower ends of the steering screw;
    所述转向螺杆的上下输入端即为所述循环球转向器的上下输入端，其输出端通过所述循环球与所述转向螺母啮合；The upper and lower input ends of the steering screw are the upper and lower input ends of the recirculating ball steering device, and its output end is engaged with the steering nut through the recirculating ball;
    所述循环球导管安装在所述转向螺母上，用做循环球循环流动的通道；The circulating ball guide is installed on the steering nut and used as a channel for the circulating flow of the circulating ball;
    所述齿扇的输入端与所述转向螺母上加工的齿条啮合，其输出端与所述转向摇臂相连；The input end of the gear fan meshes with the rack processed on the steering nut, and its output end is connected with the steering rocker arm;
    所述卸荷阀安装在所述转向螺母内，用于当转向螺母移动至极限位置时平衡其两侧的压力；The unloading valve is installed in the steering nut and is used to balance the pressure on both sides of the steering nut when it moves to the limit position;
    所述齿轮泵的输入端与所述液压电机的输出端相连，其进油口通过液压管路与所述油壶相连，出油口与所述转向阀相连；The input end of the gear pump is connected to the output end of the hydraulic motor, its oil inlet is connected to the oil pot through a hydraulic pipeline, and its oil outlet is connected to the steering valve;
    所述油壶的回油口与所述转向阀通过液压管路相连，其出油口与所述齿轮泵通过液压管路相连；The oil return port of the oil pot is connected with the steering valve through a hydraulic pipeline, and its oil outlet is connected with the gear pump through a hydraulic pipeline;
    所述限压阀和单向阀安装在用于连接齿轮泵出油口与转向阀的液压管路和用于连接转向阀和油壶回油口的液压管路之间，前者用于限制液压管路内液压油的压力，后者为了防止液压管路出现真空；The pressure limiting valve and the one-way valve are installed between the hydraulic pipeline used to connect the oil outlet of the gear pump and the steering valve and the hydraulic pipeline used to connect the steering valve and the oil return port of the oil pot. The former is used to limit the hydraulic pressure. The pressure of hydraulic oil in the pipeline, the latter is to prevent vacuum in the hydraulic pipeline;
    所述控制模块包括：电子控制单元、方向盘转角传感器、转矩传感器、车速传感器；The control module includes: an electronic control unit, a steering wheel angle sensor, a torque sensor, and a vehicle speed sensor;
    所述电子控制单元的输入端与所述方向盘转角传感器、转矩传感器、车速传感器电气相连，其输出端与所述助力电机、液压电机电气连接，转向时根据从各传感器得到的车辆转态参数，进行助力控制；The input end of the electronic control unit is electrically connected to the steering wheel angle sensor, torque sensor, and vehicle speed sensor, and its output end is electrically connected to the booster motor and hydraulic motor. , to carry out boost control;
    所述方向盘转角传感器安装在方向盘上，用于获得车辆转向时的方向盘转角信号，并将方向盘转角信号传递到所述电子控制单元；The steering wheel angle sensor is installed on the steering wheel to obtain the steering wheel angle signal when the vehicle is turning, and transmit the steering wheel angle signal to the electronic control unit;
    所述转矩传感器安装在所述转向轴上，用于获取转矩信号，并将转矩信号传递给所述电子控制单元；The torque sensor is installed on the steering shaft to obtain a torque signal and transmit the torque signal to the electronic control unit;
    所述车速传感器安装在车辆上，用于将获得的车速信号传递到所述电子控制单元；The vehicle speed sensor is installed on the vehicle, and is used to transmit the obtained vehicle speed signal to the electronic control unit;
    此外，本发明还提供了一种电-液集成转向系统的多参数耦合优化方法，基于上述系统，包含以下步骤：In addition, the present invention also provides a multi-parameter coupling optimization method for an electro-hydraulic integrated steering system, based on the above system, including the following steps:
    (1)建立电-液集成转向系统的数学模型；(1) Establish the mathematical model of the electro-hydraulic integrated steering system;
    (2)根据步骤(1)中建立的系统模型，建立转向系统优化目标；(2) according to the system model established in the step (1), establish the optimization target of the steering system;
    (3)选取一种将在系统中应用的能量管理策略，预选可能会影响系统性能的能量管理策略和转向系统参数15个，分别对各参数取三个水平的值进行试验，即最大变动量、最小变动量和中间值，得到试验数据，分析各参数的灵敏度，选取对应的设计变量；(3) Select an energy management strategy to be applied in the system, pre-select 15 energy management strategies and steering system parameters that may affect system performance, and test each parameter at three levels, that is, the maximum variation , the minimum variation and the median value, get the test data, analyze the sensitivity of each parameter, and select the corresponding design variables;
    (4)将步骤(3)中选择的设计变量，并确定各参数对应的约束条件，根据步骤(1)中的系统模型和步骤(2)中的优化目标，建立优化模型；(4) with the design variable selected in the step (3), and determine the constraint condition corresponding to each parameter, according to the system model in the step (1) and the optimization target in the step (2), set up the optimization model;
    (5)基于步骤(4)中建立的优化模型，采用优化算法求解出最优的结构及能量管理策略参数。(5) Based on the optimization model established in step (4), an optimization algorithm is used to solve the optimal structure and energy management strategy parameters.
  2. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，其特征在于，所述步骤(1)中电-液集成转向系统数学模型建立步骤如下：An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, characterized in that the steps for establishing the mathematical model of the electro-hydraulic integrated steering system in the step (1) are as follows:
    步骤(1.1)机械传动部分模型Step (1.1) Mechanical transmission part model
    a.方向盘与转向轴模型：a. Steering wheel and steering shaft model:
    考虑转向盘转动惯量与粘性阻尼忽略其刚度，忽略库仑摩擦力，则其数学模型为：Considering the moment of inertia and viscous damping of the steering wheel, ignoring its stiffness and Coulomb friction, its mathematical model is:
    Figure PCTCN2022092942-appb-100001
    Figure PCTCN2022092942-appb-100001
    T s＝K s(θ w-θ s) T s ＝K s (θ w -θ s )
    式中，J w为方向盘的转动惯量；B w为方向盘的阻尼系数；K s为转矩传感器中扭杆刚度；θ w为方向盘转角；θ s为转向轴转角；T w为方向盘输入转矩T s为转矩传感器输出转矩； In the formula, J w is the moment of inertia of the steering wheel; B w is the damping coefficient of the steering wheel; K s is the torsion bar stiffness in the torque sensor; θ w is the steering wheel angle; θ s is the steering shaft angle; T w is the input torque of the steering wheel T s is the output torque of the torque sensor;
    b.循环球转向器模型：b. Recirculating ball diverter model:
    Figure PCTCN2022092942-appb-100002
    Figure PCTCN2022092942-appb-100002
    式中，J g是转向螺杆与电动助力模块减速机构的等效转动惯量，B g是转向螺杆与减速机构的等效粘性阻尼系数，K w为转向轴刚度，θ g是转向螺杆转角，η g是转向螺杆进给效率，d g为转向螺杆的导程，T EPS为电动助力模块助力转矩，T p为转向阻力矩在齿扇上的等效力矩，r p为齿扇节圆半径，F HPS为液压助力模块所提供的助力，d r为等效到转向螺杆上的路面随机干扰力矩； In the formula, J g is the equivalent moment of inertia of the steering screw and the reduction mechanism of the electric power booster module, B g is the equivalent viscous damping coefficient of the steering screw and the reduction mechanism, K w is the stiffness of the steering shaft, θ g is the rotation angle of the steering screw, η g is the feed efficiency of the steering screw, d g is the lead of the steering screw, T EPS is the power assist torque of the electric power assist module, T p is the equivalent torque of the steering resistance torque on the gear sector, and r p is the pitch circle radius of the gear sector , F HPS is the power boost provided by the hydraulic power booster module, d r is the road random disturbance moment equivalent to the steering screw;
    液压模块助力表示为：The power assist of the hydraulic module is expressed as:
    F HPS＝A p(P A-P B) F HPS ＝A p (P A -P B )
    式中，A p为液压缸活塞的有效面积，P A、P B分别表示液压缸两端压力； In the formula, A p is the effective area of the piston of the hydraulic cylinder, and P A and P B respectively represent the pressure at both ends of the hydraulic cylinder;
    步骤(1.2)液压助力模块模型Step (1.2) hydraulic booster module model
    a.齿轮泵模型a. Gear pump model
    齿轮泵输入转矩：Gear pump input torque:
    T hm＝qP s T hm =qP s
    式中，q为齿轮泵平均排量，P s为齿轮泵工作压强，T hm为齿轮泵输入转矩； In the formula, q is the average displacement of the gear pump, P s is the working pressure of the gear pump, and T hm is the input torque of the gear pump;
    齿轮泵工作时的压强表示为：The pressure when the gear pump is working is expressed as:
    P s＝2πηT hm/q P s =2πηT hm /q
    式中，π为圆周率常数，η为液压泵机械效率；In the formula, π is the constant of pi, and η is the mechanical efficiency of the hydraulic pump;
    齿轮泵工作时的平均排量表示为：The average displacement of the gear pump is expressed as:
    q＝ζ2πm 2Zb q=ζ2πm 2 Zb
    式中，ζ为补偿系数，m为齿轮泵的齿轮模数，Z为齿轮泵的齿轮齿数，b为齿轮的齿宽，In the formula, ζ is the compensation coefficient, m is the gear modulus of the gear pump, Z is the number of teeth of the gear pump, b is the tooth width of the gear,
    齿轮泵工作时的输出流量表示为：The output flow of the gear pump is expressed as:
    Q＝qnη V＝2πkm 2Zbnη V Q＝qnη V ＝2πkm 2 Zbnη V
    式中，n为齿轮泵转速，η V为齿轮泵的容积效率，Q为齿轮泵输出流量； In the formula, n is the speed of the gear pump, η V is the volumetric efficiency of the gear pump, and Q is the output flow of the gear pump;
    b.液压电机模型b. Hydraulic motor model
    液压电机电气特性数学模型为：The mathematical model of the electrical characteristics of the hydraulic motor is:
    Figure PCTCN2022092942-appb-100003
    Figure PCTCN2022092942-appb-100003
    P h＝u hi h P h = u h i h
    式中，P h为液压电机功率，u h为液压电机电枢电压，i h为液压电机电枢电流，R h为液压电机的电枢电阻，L h为电枢电感，θ h为液压电机转角，K h为反电动势常数； In the formula, P h is the hydraulic motor power, u h is the hydraulic motor armature voltage, i h is the hydraulic motor armature current, R h is the hydraulic motor armature resistance, L h is the armature inductance, θ h is the hydraulic motor Rotation angle, K h is the counter electromotive force constant;
    液压电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the hydraulic motor is:
    Figure PCTCN2022092942-appb-100004
    Figure PCTCN2022092942-appb-100004
    式中，J h为液压电机转动惯量，θ h为液压电机转角，B h为液压电机轴阻尼系数，T h为液压电机电磁转矩，T hm为液压电机输出转矩； In the formula, J h is the moment of inertia of the hydraulic motor, θ h is the rotation angle of the hydraulic motor, B h is the damping coefficient of the hydraulic motor shaft, T h is the electromagnetic torque of the hydraulic motor, and T hm is the output torque of the hydraulic motor;
    液压电机电磁转矩方程为：The electromagnetic torque equation of the hydraulic motor is:
    T h＝K hii h T h = K hi i h
    式中，K hi为液压电机转矩系数； In the formula, K hi is the hydraulic motor torque coefficient;
    c.转向阀模型c. Steering valve model
    转向阀模型表示为：The steering valve model is expressed as:
    Figure PCTCN2022092942-appb-100005
    Figure PCTCN2022092942-appb-100005
    式中，Q V为阀体的总进油流量，Q L1、Q L2分别为动力油缸的进出油流量； In the formula, Q V is the total oil inlet flow of the valve body, Q L1 and Q L2 are the oil inlet and outlet flow of the power cylinder respectively;
    转向阀各个阀口液压油流量与压力差的关系表示为：The relationship between the hydraulic oil flow rate and the pressure difference at each valve port of the steering valve is expressed as:
    Figure PCTCN2022092942-appb-100006
    Figure PCTCN2022092942-appb-100006
    式中，Q i(i＝1,2,3,4)为流经阀口i的流量，C d为流量系数，ΔP i为第i个阀口的两侧压力差，ρ为液压油的密度，A i为第i个阀口的节流面积，阀的结构一般为对称设计，即A 1＝A 3，A 2＝A 4； In the formula, Q i (i=1, 2, 3, 4) is the flow rate flowing through the valve port i, C d is the flow coefficient, ΔP i is the pressure difference between the two sides of the i-th valve port, and ρ is the pressure of the hydraulic oil Density, A i is the throttling area of the i-th valve port, and the structure of the valve is generally designed symmetrically, that is, A 1 = A 3 , A 2 = A 4 ;
    转向阀各个阀口的开口面积表示为：The opening area of each valve port of the steering valve is expressed as:
    Figure PCTCN2022092942-appb-100007
    Figure PCTCN2022092942-appb-100007
    式中，θ g-θ l表示转向螺杆与转向阀之间产生的相对转角，θ l为转向阀转角，R为转向阀和转向螺杆的配合半径，W 1为转向阀切口的宽度，W 2为中位时转向阀口的预开间隙宽度，L 1为切口轴向长度，L 2为转向阀口的轴向长度； In the formula, θ g - θ l represents the relative rotation angle between the steering screw and the steering valve, θ l is the steering valve rotation angle, R is the matching radius of the steering valve and the steering screw, W 1 is the width of the steering valve cutout, W 2 is the pre-opening gap width of the steering valve port in the neutral position, L 1 is the axial length of the cutout, and L 2 is the axial length of the steering valve port;
    步骤(1.3)电动助力模块模型Step (1.3) electric power booster module model
    助力电机电气特性数学模型为：The mathematical model of the electrical characteristics of the booster motor is:
    Figure PCTCN2022092942-appb-100008
    Figure PCTCN2022092942-appb-100008
    P e＝u ei e P e = u e i e
    式中，P e为助力电机功率，u e为助力电机电枢电压，i e为助力电机电枢电流，R e为助力电机的电枢电阻，L e为电枢电感，θ e为助力电机转角，K e为反电动势常数； In the formula, P e is the power of the booster motor, u e is the armature voltage of the booster motor, i e is the armature current of the booster motor, R e is the armature resistance of the booster motor, L e is the armature inductance, and θ e is the booster motor Rotation angle, K e is the counter electromotive force constant;
    助力电机机械特性数学模型为：The mathematical model of the mechanical characteristics of the booster motor is:
    Figure PCTCN2022092942-appb-100009
    Figure PCTCN2022092942-appb-100009
    式中，J e为助力电机转动惯量，θ e为助力电机转角，B e为助力电机轴阻尼系数，T e为助力电机电磁转矩，T em为助力电机输出转矩； In the formula, J e is the moment of inertia of the booster motor, θ e is the rotation angle of the booster motor, Be is the damping coefficient of the booster motor shaft, T e is the electromagnetic torque of the booster motor, and T em is the output torque of the booster motor;
    助力电机电磁转矩方程为：The electromagnetic torque equation of the booster motor is:
    T e＝K eii e T e =K ei i e
    式中，K ei为助力电机转矩系数； In the formula, K ei is the torque coefficient of the booster motor;
    电动助力模块所提供的助力T EPS表达式为： The power assist T EPS expression provided by the electric power assist module is:
    T EPS＝T emG star T EPS = T em G star
    式中，G star是行星齿轮减速器的减速比。 In the formula, G star is the reduction ratio of the planetary gear reducer.
  3. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，其特征在于，所述步骤(2)中的优化目标为：An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, characterized in that, the optimization target in the step (2) is:
    步骤(2.1)转向路感优化目标f1：Step (2.1) Turn to the road feeling optimization target f1:
    Figure PCTCN2022092942-appb-100010
    Figure PCTCN2022092942-appb-100010
    式中，ω为系统频率，ω0＝40Hz为截止频率，j为虚数单位，X1、Y1、Z1分别为等效转动惯量、阻尼和刚度系数；In the formula, ω is the system frequency, ω0=40Hz is the cut-off frequency, j is the imaginary number unit, X1, Y1, Z1 are the equivalent moment of inertia, damping and stiffness coefficient respectively;
    步骤(2.2)转向灵敏度优化目标f2：Step (2.2) turns to the sensitivity optimization target f2:
    Figure PCTCN2022092942-appb-100011
    Figure PCTCN2022092942-appb-100011
    式中，Ai(i＝0,1,2,3)为传递函数分子系数，Qi(i＝0,1,2,3,4,5)为传递函数分母系数；In the formula, Ai (i=0,1,2,3) is the numerator coefficient of the transfer function, Qi (i=0,1,2,3,4,5) is the denominator coefficient of the transfer function;
    步骤(2.3)转向能耗优化目标f3：Step (2.3) turns to energy consumption optimization target f3:
    Figure PCTCN2022092942-appb-100012
    Figure PCTCN2022092942-appb-100012
    式中，T n为转向需求转矩，n e为助力电机转速 In the formula, T n is the steering demand torque, n e is the speed of the assist motor
    步骤(2.4)系统成本优化目标：Step (2.4) system cost optimization goal:
    f 4＝C(P e,P h,G star,d g,d,r p) f 4 ＝C(P e ,P h ,G star ,d g ,d,r p )
  4. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，所述步骤(3)中灵敏度分析步骤为：According to the electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, the sensitivity analysis step in the step (3) is:
    步骤(3.1)分别对15个参数对转向路感目标进行极差分析，得到所选取的八个系统参数对转向路感目标的灵敏度大小的顺序，确定其对应的设计变量参数；Step (3.1) carries out range analysis to 15 parameters respectively to steering road feeling target, obtains the order of the sensitivity size of eight selected system parameters to steering road feeling target, determines its corresponding design variable parameter;
    步骤(3.2)分别将15个系统参数对转向灵敏度目标进行极差分析，得到所选取的八个系统参数对转向灵敏度目标的灵敏度大小的顺序，确定其对 应的设计变量参数；Step (3.2) carries out range analysis with 15 system parameters respectively to the steering sensitivity target, obtains the order of the sensitivity size of the selected eight system parameters to the steering sensitivity target, and determines its corresponding design variable parameter;
    步骤(3.3)分别将15个系统参数对转向能耗目标进行极差分析，得到所选取的八个系统参数对转向能耗目标的灵敏度大小的顺序，确定其对应的设计变量参数；Step (3.3) carries out range analysis to 15 system parameters respectively to the steering energy consumption target, obtains the order of the sensitivity of the selected eight system parameters to the steering energy consumption target, and determines its corresponding design variable parameters;
    步骤(3.4)分别将15个系统参数对系统成本目标进行极差分析，得到所选取的八个系统参数对系统成本目标的灵敏度大小的顺序，确定其对应的设计变量参数；Step (3.4) carries out range analysis to 15 system parameters respectively to the system cost target, obtains the order of the sensitivity of the selected eight system parameters to the system cost target, and determines its corresponding design variable parameters;
  5. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，其特征在于，所述步骤(3)中选取的能量管理策略为基于模糊规则的能量管理策略，所述最终的设计变量为模糊规则中电动助力模块输出转矩的隶属度函数节点Oe，液压助力模块的隶属度函数节点Oh，需求转矩的隶属度函数节点On，液压电机功率Ph，助力电机功率Pe，行星齿轮减速比Gstar，转向螺杆导程dg，齿扇节圆半径rp，齿轮泵直径d；An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, wherein the energy management strategy selected in the step (3) is an energy management strategy based on fuzzy rules, and the The final design variables are the membership function node Oe of the output torque of the electric power booster module in the fuzzy rules, the membership function node Oh of the hydraulic power booster module, the membership function node On of the demand torque, the power of the hydraulic motor Ph, and the power of the booster motor Pe , planetary gear reduction ratio Gstar, steering screw lead dg, pitch circle radius rp, gear pump diameter d;
  6. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，所述步骤(4)中建立的优化模型为：According to the electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, the optimization model established in the step (4) is:
    Figure PCTCN2022092942-appb-100013
    Figure PCTCN2022092942-appb-100013
    式中，f 1(X)为转向路感优化目标，f 2(X)为转向灵敏度指标优化目标，f 3(X)为转向能耗优化目标，f 4(X)为系统成本优化目标。 In the formula, f 1 (X) is the optimization target of steering road feeling, f 2 (X) is the optimization target of steering sensitivity index, f 3 (X) is the optimization target of steering energy consumption, and f 4 (X) is the optimization target of system cost.
  7. 根据权利要求1所述的一种电液集成式转向系统及其多参数耦合优化方法，其特征在于，所述步骤(5)中所用的优化方法选用多目标粒子群优化算法，具体步骤如下：An electro-hydraulic integrated steering system and its multi-parameter coupling optimization method according to claim 1, wherein the optimization method used in the step (5) is a multi-objective particle swarm optimization algorithm, and the specific steps are as follows:
    步骤(5.1)初始化粒子种群m，随机生成初始位置X0和初始速度V0，粒子的初始个体最优位置Pbest＝X0：Step (5.1) Initialize the particle population m, randomly generate the initial position X0 and the initial velocity V0, the initial individual optimal position of the particle Pbest=X0:
    Figure PCTCN2022092942-appb-100014
    Figure PCTCN2022092942-appb-100014
    外部档案Ns为空，迭代次数设为M，迭代过程中第i个粒子的位置和速度向量表示为：The external file Ns is empty, the number of iterations is set to M, and the position and velocity vectors of the i-th particle during the iteration process are expressed as:
    Figure PCTCN2022092942-appb-100015
    Figure PCTCN2022092942-appb-100015
    式中，PbestK(K＝X)为设计变量对应的最优位置分量，XiK(K＝X)为各设计变量对应的位置分量，ViK(K＝X)为各设计变量对应的速度分量；In the formula, PbestK(K=X) is the optimal position component corresponding to the design variable, XiK(K=X) is the position component corresponding to each design variable, and ViK(K=X) is the velocity component corresponding to each design variable;
    步骤(5.2)计算每个粒子的目标函数，将非支配解存入外部档案中；Step (5.2) calculates the objective function of each particle, and stores the non-dominated solution in an external file;
    步骤(5.3)计算外部档案中每个个体距粒子中心Xcenter的欧式距离：Step (5.3) Calculate the Euclidean distance from each individual in the external archive to the particle center Xcenter:
    d ij＝||X i-X center|| d ij ＝||X i -X center ||
    按照轮盘赌选择方法，随机选择外部档案中的个体作为粒子的历史全局最优位置Gbest：According to the roulette selection method, the individual in the external archives is randomly selected as the historical global optimal position Gbest of the particle:
    Figure PCTCN2022092942-appb-100016
    Figure PCTCN2022092942-appb-100016
    步骤(5.4)通过上式更新粒子的位置X和速度V，同时更新粒子的Pbest，并用当前粒子群中的非支配解更新外部档案Ns：Step (5.4) Update the position X and velocity V of the particle through the above formula, update the Pbest of the particle at the same time, and update the external file Ns with the non-dominated solution in the current particle swarm:
    V i(t+1)＝V i(t)+c 1*r 1*[P best(t)-X i(t)]+c 2*r 2*[G best(t)-X i(t)] V i (t+1)＝V i (t)+c 1 *r 1 *[P best (t)-X i (t)]+c 2 *r 2 *[G best (t)-X i ( t)]
    X i(t+1)＝X i(t)+V i(t+1)Δt X i (t+1)=X i (t)+V i (t+1)Δt
    式中，c1和c2为学习因子，r1和r2为取值在0-1之间的随机数，□t为时间间隔；In the formula, c1 and c2 are learning factors, r1 and r2 are random numbers between 0 and 1, and t is the time interval;
    步骤(5.5)判断外部档案中的个体数目是否超过给定的最大容量，如果超过则删除距离中心最小的个体，否则进行下一步；Step (5.5) judge whether the number of individuals in the external file exceeds the given maximum capacity, if so, delete the individual with the smallest distance from the center, otherwise proceed to the next step;
    步骤(5.6)从外部档案中随机选择部分个体进行混沌变异，搜索附近区域的非支配解；Step (5.6) Randomly select some individuals from the external archives for chaotic mutation, and search for non-dominated solutions in nearby areas;
    步骤(5.7)若满足结束条件，则停止搜索，从外部档案中输出Pareto最 优解集，否则转步骤(5.3)再循环直至结束输出Pareto最优解集；If step (5.7) satisfies the end condition, then stop searching, output the Pareto optimal solution set from the external file, otherwise go to step (5.3) and recycle until the end of the output Pareto optimal solution set;
    步骤(5.8)设置各目标函数的优先级权重w1、w2、w3、w4，并根据目标权重从步骤(5.7)中求解的Pareto解集中选取最终的优化结果。Step (5.8) sets the priority weights w1, w2, w3, w4 of each objective function, and selects the final optimization result from the Pareto solution set solved in step (5.7) according to the objective weights.
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