CN116331342A - Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method - Google Patents
Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method Download PDFInfo
- Publication number
- CN116331342A CN116331342A CN202310469334.2A CN202310469334A CN116331342A CN 116331342 A CN116331342 A CN 116331342A CN 202310469334 A CN202310469334 A CN 202310469334A CN 116331342 A CN116331342 A CN 116331342A
- Authority
- CN
- China
- Prior art keywords
- valve
- control
- steering
- cylinder
- tie rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- 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
- B62D5/062—Details, component parts
- B62D5/064—Pump driven independently from vehicle engine, e.g. electric driven pump
-
- 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
- B62D5/18—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by power transmitting means
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/20—Links, e.g. track rods
Landscapes
- 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
The invention provides a pump control main drive tie rod auxiliary valve control electro-hydraulic steering system and a control method, wherein the control method comprises a main drive system of a variable-rotation-speed pump drive double-steering power-assisted cylinder, a tie rod auxiliary valve control system and an electronic control system; the main driving system of the variable-rotation-speed pump driving double-steering booster cylinder is a pump control system, the left and right steering booster cylinders are controlled through a servo motor pump unit and a steering booster cylinder valve group, and the split flow rate is used for controlling a tie rod auxiliary valve control system; the auxiliary valve control system of the tie rod is a valve control system, the tie rod cylinder with a large cavity and a small cavity is controlled through the valve group of the tie rod cylinder and the locking device, and the auxiliary main driving system is used for controlling the corners of the left wheel and the right wheel; the electronic control system outputs control instructions to control the rotation angles of the left wheel and the right wheel in real time according to the input target rotation angle signals and the signals of the left wheel angle sensor and the right wheel angle sensor. By the aid of the technical scheme, the pure rolling steering effect of the system can be guaranteed, and safety of the system when the system is applied to a vehicle running at a high speed is improved.
Description
Technical Field
The invention relates to the technical field of automobile steering, in particular to a pump control main drive tie rod auxiliary valve control electro-hydraulic steering system and a control method thereof.
Background
With the development of civil infrastructure construction and national defense and military modernization in China, the market demand of multi-axis vehicles is rapidly increased, so that the multi-axis vehicle technology is rapidly developed. In the military industry or the civil industry, the working conditions of the multi-axle vehicle are severe, and the multi-axle steering system is required to simultaneously meet various requirements of full-road running, multi-steering mode, large-load driving capability, high efficiency, accuracy and the like. The electrohydraulic servo steering system becomes the preferred proposal of the current multi-axle steering system due to the advantages of quick dynamic response, high output power and the like. The traditional electrohydraulic valve control trapezoidal steering system is a single-degree-of-freedom system which is provided with a power source by a constant delivery pump driven by an engine and controls a double-steering power-assisted cylinder through a servo proportional valve, and the functions of accurate steering of each wheel according to a target turning angle and on-demand supply of power of each shaft cannot be realized. And the traditional electrohydraulic valve-controlled trapezoidal steering system of the steering system has complex configuration, high cost, unavoidable overflow throttling loss, serious system energy loss and serious heating and noise. Therefore, to achieve high-precision steering and reduce system power consumption, it is necessary to design a new system configuration.
The prior art scheme is helpful for improving the performance of the electro-hydraulic servo steering system, but the following defects still exist:
1. with the increase of actuators of the whole vehicle multi-axle steering system, the conventional single pump/few pump system is difficult to adapt to the requirements of multiple actuators. Although each group of actuators can realize high precision by adopting a traditional servo valve control mode, as the number of the actuators is increased, the traditional single pump/few pump system cannot adjust the pressure flow of a pump source according to the requirement of each actuator, so that the problems of energy waste, insufficient working pressure, unreasonable pressure flow distribution and the like are caused; the heavy multi-axle vehicle has the characteristic that the length difference of tie rods of final-axle steering mechanisms in different steering modes is extremely large, challenges are brought to multi-mode and high-precision steering under complex working conditions, and a steering system with fixed length of the tie rods cannot adapt to the performance requirements of multi-mode steering.
2. The control capability and energy conservation of the two-degree-of-freedom electro-hydraulic steering system with the length of the transverse pulling cylinder adjustable are required to be improved. The two-degree-of-freedom electro-hydraulic steering system with the length adjustable transverse pull cylinder can realize multi-mode switching and give consideration to heavy load and high-precision steering, but the method increases the number of actuators, increases the difficulty of high-precision steering control under heavy load and increases energy consumption.
3. The safety of the situation that the valve control system of the tie rod cylinder fails to be self-locking is required to be enhanced. When the valve control system of the transverse pull rod cylinder cannot normally supply liquid or the hydraulic cylinder and the hydraulic lock leak due to special reasons, the transverse pull rod cylinder cannot be locked, so that the problems such as sideslip of a tire, steering out of control and the like are easily caused, and the running safety of the multi-axle vehicle is seriously influenced.
Disclosure of Invention
In view of the above, the invention aims to provide a pump-control main drive tie rod auxiliary valve-control electro-hydraulic steering system and a control method thereof. The main driving system of the variable-rotation-speed pump-driven double-steering power-assisted cylinder and the tie rod auxiliary valve control system are used for carrying out electrohydraulic servo compound control on the tie rod adjustable trapezoidal steering mechanism, so that the energy saving purpose is achieved while the multi-mode high-precision dynamic steering is realized; preferably, the steering system further comprises an external control type hydraulic lock and a locking device, so that the tie rod cylinder and the left and right steering booster cylinders can be locked when needed, the pure rolling steering effect of the system is ensured, and the safety of the system when the system is applied to a high-speed running vehicle is improved.
In order to achieve the above purpose, the invention adopts the following technical scheme: the pump-control main-drive tie rod auxiliary valve-control electro-hydraulic steering system comprises a main driving system of a variable-rotation-speed pump-drive double-steering power cylinder, a tie rod auxiliary valve-control system and an electronic control system; the main driving system of the variable-rotation-speed pump driving double-steering booster cylinder is a pump control system, the left and right steering booster cylinders are controlled through a servo motor pump unit and a steering booster cylinder valve group, and one flow is split to control the tie rod auxiliary valve control system; the auxiliary valve control system of the tie rod is a valve control system, the tie rod cylinder with a large cavity and a small cavity is controlled through the valve group of the tie rod cylinder and the locking device, and the auxiliary main driving system is used for controlling the corners of the left wheel and the right wheel; the electronic control system outputs control instructions to control the rotation angles of the left wheel and the right wheel in real time according to the input target rotation angle signals and the signals of the left wheel angle sensor and the right wheel angle sensor.
In a preferred embodiment: the main driving system of the variable-rotation-speed pump-driven double-steering power-assisted cylinder comprises a servo motor pump unit, a flowmeter, a steering power-assisted cylinder valve group, a left steering power-assisted cylinder and a right steering power-assisted cylinder; the first working oil way formed by the rodless cavity of the left steering power-assisted cylinder and the rod-free cavity of the right steering power-assisted cylinder is connected with the working oil port A of the electromagnetic reversing valve, and the second working oil way formed by the rod-free cavity of the left steering power-assisted cylinder and the rod-free cavity of the right steering power-assisted cylinder is connected with the working oil port B of the electromagnetic reversing valve; the P port of the electromagnetic reversing valve is connected with the oil inlet oil way, and the T port of the electromagnetic reversing valve is connected with the oil tank.
In a preferred embodiment: the servo motor pump unit consists of a servo motor and a constant displacement pump and is used as a pump source of a main driving system of the variable-rotation-speed pump driving double-steering booster cylinder; the pressure and flow of the main driving system are controlled by a servo motor pump unit, the direction is controlled by an electromagnetic reversing valve, the servo motor pump unit adjusts the rotating speed of a servo motor under the control of a controller so as to adapt to the change of working pressure and provide flow according to the requirement, and the main driving system also comprises four oil supplementing overflow valve groups which are respectively connected with four working oil ways in series; the oil supplementing overflow valve group is formed by connecting an overflow valve and a one-way valve in parallel.
In a preferred embodiment: the tie rod auxiliary valve control system comprises a tie rod cylinder valve group, a large cavity tie rod cylinder, a small cavity tie rod cylinder and a locking device; the large cavity working oil way of the large and small cavity transverse pull rod cylinder is connected with an A port of the servo proportional valve, the small cavity working oil way is connected with a B port of the servo proportional valve to form a third working oil way and a fourth working oil way respectively, and the locking device is positioned at the small cavity end of the large and small cavity transverse pull rod cylinder; the P port of the servo proportional valve is connected with an oil inlet oil way, and the T port of the servo proportional valve is connected with an oil tank; the tie rod auxiliary valve control system shares a pump source with the main drive system.
In a preferred embodiment: a branch of flow is separated from the main driving system, and a servo proportional valve is adopted to control the transverse pull rod cylinder; the large-small cavity tie rod cylinder is a double-rod-outlet cylinder optimally designed by structural parameters; the working areas of rod cavities on two sides of the transverse pull rod cylinder are unequal, and a locking device is connected to the small cavity end cover.
In a preferred embodiment: the method comprises the steps of optimizing structural parameters of a large-and-small-cavity tie rod cylinder by adopting a multi-objective optimization method based on a genetic algorithm, selecting driving power and steering driving force as optimization targets, taking pressure and flow parameters of a tie rod auxiliary valve control system as constraint conditions, taking area of the large-and-small-cavity, cylinder diameter, rod diameter and stroke structural parameters as optimization parameters, and constructing a multi-objective optimization model of the large-and-small-cavity hydraulic cylinder, wherein the multi-objective optimization model of the large-and-small-cavity hydraulic cylinder is as follows:
wherein P is driving power; f is steering driving force; x is X 1 ,…,X n The optimization parameters of the hydraulic cylinders with the large and small cavities are adopted;
respectively taking the minimum and the maximum values of the ith constraint condition;/>
respectively taking the minimum value and the maximum value of the ith optimization parameter, and constructing a multi-objective optimization genetic algorithm fitness function for the structural parameters of the large and small cavity hydraulic cylinders by utilizing a genetic algorithm as follows:
wherein θ i Fitness for the ith individual; a. b is an adaptability parameter used for adjusting the weight of the driving power and the steering driving force in the optimization; p (P) i 、F i Predicted values of the i-th individual driving power and the steering driving force, respectively; the theta is as follows i The smaller the driving power corresponding to the individual, the larger the steering driving force.
In a preferred embodiment: the locking device forms wedge-shaped locking through the conical locking ring and the conical sleeve to form mechanical self-locking; the control port of the locking device is connected with a first reversing ball valve, the first reversing ball valve is electrified, and the locking device and the hydraulic lock work together to self-lock the large and small cavity transverse pull rod cylinders;
in a preferred embodiment: the hydraulic control one-way valve and the reversing ball valve form an external control type hydraulic lock which is respectively connected with an A port and a B port of the servo proportional valve and the electromagnetic reversing valve in series; the first reversing ball valve and the second reversing ball valve are two-position three-way valves, and the hydraulic lock is locked by the electricity of the reversing ball valves.
The invention provides a control method of an electrohydraulic steering system controlled by a pump control main drive tie rod auxiliary valve, which adopts the electrohydraulic steering system controlled by the pump control main drive tie rod auxiliary valve: the method comprises the following steps:
step S1: the electrohydraulic servo steering system inputs left and right target rotation angle signals of a controlled steering axle to the controller;
step S2: judging whether locking of the large-small cavity transverse pull rod cylinder is needed or not: if not, jumping to the step S3; if necessary, jumping to step S8;
step S3: the controller takes the target rotation angle signals of the left and right wheels as two control targets to control the system;
step S4: detecting actual rotation angles of left and right wheels of a controlled steering axle, and respectively calculating deviation between the actual rotation angles of the left and right wheels and a target rotation angle;
step S5: according to the deviation signal of the target rotation angle of the left wheel and the current rotation angle, the controller sends a signal to the servo motor and the electromagnetic directional valve to control the work of the servo motor and the electromagnetic directional valve; controlling the servo proportional valve to work according to a deviation signal of a target rotation angle of the right wheel and a current rotation angle;
step S6: the servo proportional valve outputs a hydraulic signal to control the expansion and contraction of the large-cavity and small-cavity transverse pull rod cylinder, and the servo motor pump unit and the electromagnetic reversing valve control the left and right side steering power cylinders to expand and contract together so that the left or right wheels reach a target rotation angle;
step S7: judging whether the left wheel rotation angle deviation signal is larger than a critical rotation angle threshold value of 0.2 degrees: if yes, jumping to the step S3; if not, jumping to the step S8;
step S8: setting a servo proportional valve to be in a middle position, powering a first reversing ball valve, leading oil of a first hydraulic control one-way valve and a second hydraulic control one-way valve to pass through an oil return cavity, and locking a tie rod cylinder;
step S9: synchronous with step S8, calculating the deviation between the left and right side wheels and the target rotation angle;
step S10: the controller sends command signals to the servo motor and the electromagnetic reversing valve according to the deviation between the actual rotation angle of the left wheel and the target rotation angle to control the left and right steering power cylinders to stretch and retract so as to reach the target rotation angle;
in a preferred embodiment: the servo motor changes the rotating speed of the motor through a voltage control signal so as to adjust the output flow and pressure of the constant displacement pump; the electromagnetic directional valve is controlled by using angular velocity feedforward-angle feedback control, the left turn is set to be positive, the deviation angle between the target turning angle and the actual turning angle of the left steering wheel is used as a feedback signal, the target angular velocity is used as a feedforward signal, the sum of the feedback signal and the feedforward signal is used as a control signal, and the function of the control signal is as follows:
U＝(θ q -θ s )+ω q
wherein U is a control signal, θ q For the target rotation angle theta s For the actual rotation angle omega q Is the target angular velocity.
Compared with the prior art, the invention has the following beneficial effects:
1. the pump control main drive/horizontal pull rod auxiliary valve control electrohydraulic steering system is designed based on the two-degree-of-freedom mechanism with the length of the horizontal pull cylinder being adjustable, so that the system is more efficient and energy-saving and always works in the optimal performance state. A servo motor pump unit formed by a servo motor and a fixed displacement pump is arranged for each steering shaft to serve as a pump source, an electromagnetic reversing valve is used for replacing a servo proportional valve in a traditional system in a main driving system, so that the pressure flow of the steering system is directly controlled through the servo motor pump unit, the load power is supplied as required, the system is more efficient and energy-saving, meanwhile, the control cavity pressure of a steering power cylinder is directly controlled by the servo motor pump unit, and the system and a pressure control algorithm thereof are simplified; furthermore, a small flow is separated on the basis of the main driving system, and the servo proportional valve is adopted to control the auxiliary valve control system of the transverse pull rod, so that the system can simultaneously control the steering angles of wheels at two sides, the constraint condition under the working condition of the whole road surface is met, and the high-precision control of the steering system is realized.
2. The novel large and small cavity transverse pull rod servo cylinder is designed according to the requirement of the pump control main drive/transverse pull rod auxiliary valve control electro-hydraulic steering system, so that the control capability and energy conservation of the transverse pull rod cylinder are improved. By designing the structural parameters of the cross-draw bar cylinder, such as the large and small cavity area, the cylinder diameter, the rod diameter and the like, the maximum steering driving force and the minimum driving power are matched, and the control capability and the energy conservation of the system are improved; furthermore, the locking or unlocking of the external control type hydraulic lock on the auxiliary branch loop to the tie rod cylinder is controlled, so that the multi-mode switching functions of the pump control main drive/tie rod auxiliary valve control electro-hydraulic steering system, such as minimum turning radius, controllable tie rod, crab-tie rod locking and the like, are realized.
3. The safety of the multi-shaft automobile steering system is ensured by carrying out hydraulic and mechanical double self-locking on the large and small cavity transverse pull rod cylinders. The external control type hydraulic lock is used for self-locking the large and small cavity tie rod cylinders, and simultaneously, the locking device connected with the small cavity end cover is used for mechanically self-locking the tie rod cylinders, so that double guarantee is provided for self-locking of the tie rod cylinders, and the safety of a steering system is improved.
Drawings
FIG. 1 is a schematic illustration of a pump-controlled primary drive/tie rod assist valve-controlled electro-hydraulic steering system in accordance with a preferred embodiment of the present invention;
FIG. 2 is a flowchart of a method for multi-objective optimization design of a large and small cavity tie rod cylinder based on a genetic algorithm in accordance with a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of a large and small cavity tie rod cylinder locking arrangement in accordance with a preferred embodiment of the present invention;
FIG. 4 is a flow chart of a steering control method of the system according to the preferred embodiment of the present invention;
in the figure: 1. an oil tank; 2. a stop valve; 3. a servo motor; 4. a fixed displacement pump; 5. a one-way valve; 6. an overflow valve; 7. a flow meter; 8. a servo proportional valve; 9. a first reversing ball valve; 10. a first pilot operated check valve; 11. a second pilot operated check valve; 12. the first oil supplementing overflow valve bank; 13. the second oil supplementing overflow valve bank; 14. a valve group of the transverse pull rod cylinder; 15. a left steering wheel; 16. a frame; 17. a left angle sensor; 18. a left steering assist cylinder; 19. a locking device; 20. a large and small cavity transverse pull rod cylinder; 21. a right steering assist cylinder; 22. a right steering wheel; 23. a right angle sensor; 24. a controller; 25. a third pilot operated check valve; 26. a fourth pilot operated check valve; 27. a steering cylinder valve bank; 28. the third oil supplementing overflow valve group; 29. a fourth oil supplementing overflow valve group; 30. an electromagnetic reversing valve; 31. the second reversing ball valve; 32. a stop valve; 33. a filter; 34. a one-way valve; 35. a filter; 36. a servo motor pump unit; 37. a piston rod; 38. a seal ring; 39. a locking device mounting seat; 40. an oil inlet of the locking device; 41. a conical locking ring; 42. a spring; 43. a small cavity end cover.
Detailed Description
The invention will be further described with reference to the accompanying drawings and examples.
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application; as used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
Referring to fig. 1 to 4, the pump-controlled main drive tie rod auxiliary valve-controlled electro-hydraulic steering system comprises a main drive system of a variable-rotation-speed pump-driven double-steering power cylinder, a tie rod auxiliary valve-controlled system and an electronic control system; the main driving system of the variable-rotation-speed pump-driven double-steering power-assisted cylinder comprises an oil tank 1, a servo motor pump unit 36, a one-way valve 5, a filter 33, a flowmeter 7, a steering power-assisted cylinder valve group 27, a left steering power-assisted cylinder 18 and a right steering power-assisted cylinder 21; a first working oil path R1 formed by a rodless cavity of the left steering power cylinder 18 and a rod cavity of the right steering power cylinder 21 is connected with an A working oil port of the electromagnetic directional valve 30, and a second working oil path R2 formed by the rod cavity of the left steering power cylinder 18 and the rodless cavity of the right steering power cylinder 21 is connected with a B working oil port of the electromagnetic directional valve 30; the tie rod auxiliary valve control system comprises a tie rod cylinder valve group 14, a large and small cavity tie rod cylinder 20 and a locking device 19; the large cavity working oil way of the large and small cavity transverse pull rod cylinder 20 is connected with an A port of the servo proportional valve 8, and the small cavity working oil way is connected with a B port of the servo proportional valve 8 to respectively form a third working oil way R3 and a fourth working oil way R4; the P port of the servo proportional valve 8 and the P port of the electromagnetic directional valve 30 are connected with an oil inlet circuit, and the T port of the servo proportional valve is connected with an oil tank; the electronic control system comprises a controller 24, a servo motor 3, a left wheel angle sensor 17 and a right wheel angle sensor 23; the controller is connected with the servo motor 3, the electromagnetic directional valve 30, the servo proportional valve 8, the first directional ball valve 9, the second directional ball valve 31 and the left and right wheel angle sensors respectively, is used for calculating deviation between target rotation angles and actual rotation angles of left and right steering wheels, and sends real-time control signals to the servo motor 3, the electromagnetic directional valve 30, the servo proportional valve 8 and the directional ball valves according to calculation results.
The main driving system of the variable-rotation-speed pump driving double-steering booster cylinder adopts a servo motor pump unit as a pump source, and the unit is composed of a servo motor 3 and a constant displacement pump 4; the pressure and flow of the main drive system is controlled by a servomotor pump unit, the direction of which is controlled by an electromagnetic directional valve 30, which adjusts the rotation speed of the servomotor 3 under the control of the controller 24 to adapt the working pressure variation and provide flow as required.
The main driving system realizes steering of left and right wheels by controlling left and right steering booster cylinders, the tie rod auxiliary valve control system carries out auxiliary control on steering angles by controlling the extension and retraction of the tie rod cylinders, and the tie rod auxiliary valve control system shares a pump source with the main driving system, divides one flow from the main driving system and controls the tie rod cylinders by adopting a servo proportional valve.
The large and small cavity tie rod cylinders 20 are double-rod-outlet cylinders which are optimally designed, and the working areas of rod cavities on two sides of each tie rod cylinder are unequal.
The structural parameter optimization of the large and small cavity tie rod cylinders 20 adopts a multi-objective optimization method based on a genetic algorithm, driving power and steering driving force are selected as optimization targets, parameters such as pressure, flow and the like of a tie rod auxiliary valve control system are used as constraint conditions, the structural parameters such as large and small cavity area, cylinder diameter, rod diameter, stroke and the like are used as optimization parameters, a multi-objective optimization model of the large and small cavity hydraulic cylinders is constructed, and the multi-objective optimization model of the large and small cavity hydraulic cylinders is as follows:
wherein P is driving power; f is steering driving force; x is X 1 ,…,X n The optimization parameters of the hydraulic cylinders with the large and small cavities are adopted;
respectively taking the minimum and the maximum values of the ith constraint condition; />
Respectively taking the minimum value and the maximum value of the ith optimization parameter;
carrying out multi-objective optimization on structural parameters of the large and small cavity hydraulic cylinders by utilizing a genetic algorithm, generating n individuals as a population in the range of the optimized parameters, and calculating the fitness of each individual in the population; sorting individuals according to fitness, eliminating individuals with low fitness, and keeping individuals with high fitness; the reserved individuals generate a new population through crossing and mutation, the crossing is realized by exchanging a certain optimization parameter of the two individuals, and the mutation is realized by changing a random optimization parameter of a random individual; the genetic algorithm fitness function is constructed as follows:
wherein θ i Fitness for the ith individual; a. b is an adaptability parameter used for adjusting the weight of the driving power and the steering driving force in the optimization; p (P) i 、F i Predicted values of the i-th individual driving power and the steering driving force, respectively; the theta is as follows i The smaller the driving power corresponding to the individual is, the larger the steering driving force is;
the small cavity end cover of the large and small cavity tie rod cylinder 20 is connected with a locking device 19, and the mechanical self-locking of the tie rod cylinder is completed by wedge locking formed by the conical locking ring 41 and the locking device mounting seat 39. The locking device oil inlet 40 is connected with the first reversing ball valve 9, the first reversing ball valve 9 is powered, and the large and small cavity transverse pull rod cylinders 20 form mechanical self-locking. The structure of the locking device is shown in fig. 3.
When the self-locking is needed, the first reversing ball valve 9 is powered on, the locking device oil inlet 40 is in decompression, the conical locking ring 41 is pressed tightly under the action of the spring 42, the friction force between the conical locking ring 41 and the piston rod 37 is increased, and meanwhile, the conical locking ring 41 is also driven to be locked due to the constant tensile force of the transverse pull rod cylinder until the piston rod is locked, so that the mechanical self-locking is completed.
When the unlocking is needed, the first reversing ball valve 9 is powered off, the pressure oil is introduced into the locking device oil inlet 40, and hydraulic oil presses the conical locking ring 41 to enable the piston rod 37 to be loosened to complete unlocking.
Preferably, the system further comprises four oil supplementing overflow valve groups which are respectively connected with the four working oil ways in series; the oil supplementing overflow valve group is formed by connecting an overflow valve and a one-way valve in parallel.
Preferably, the hydraulic control one-way valve and the reversing ball valve form an external control hydraulic lock which is respectively connected in series with the AB port of the servo proportional valve 8 and the AB port of the electromagnetic reversing valve 30; the first reversing ball valve 9 and the second reversing ball valve 31 are two-position three-way valves, and the ball valves are electrically used for locking the hydraulic lock.
Preferably, the servo motor 3 changes the motor rotation speed through a voltage control signal so as to adjust the output flow and pressure of the constant displacement pump 4; the response speed of the electromagnetic directional valve 30 is improved by using the feed-forward compensation method.
Figure 4 is a flow chart of a steering control method of the system according to the present invention.
The method comprises the following steps:
step S1: the electrohydraulic servo steering system inputs left and right target rotation angle signals of a controlled steering axle to the controller;
step S2: judging whether locking of the large-small cavity transverse pull rod cylinder is needed or not: if not, jumping to the step S3; if necessary, jumping to step S8;
step S3: the controller takes the target rotation angle signals of the left and right wheels as two control targets to control the system;
step S4: detecting actual rotation angles of left and right wheels of a controlled steering axle, and respectively calculating deviation between the actual rotation angles of the left and right wheels and a target rotation angle;
step S5: according to the deviation signal of the target rotation angle of the left wheel and the current rotation angle, the controller sends a signal to the servo motor and the electromagnetic directional valve to control the work of the servo motor and the electromagnetic directional valve; controlling the servo proportional valve to work according to a deviation signal of a target rotation angle of the right wheel and a current rotation angle;
step S6: the servo proportional valve outputs a hydraulic signal to control the expansion and contraction of the large-cavity and small-cavity transverse pull rod cylinder, and the servo motor pump unit and the electromagnetic reversing valve control the left and right side steering power cylinders to expand and contract together so that the left or right wheels reach a target rotation angle;
step S7: judging whether the left wheel rotation angle deviation signal is larger than a critical rotation angle threshold value of 0.2 degrees: if yes, jumping to the step S3; if not, jumping to the step S8;
step S8: setting a servo proportional valve to be in a middle position, powering a first reversing ball valve, leading oil of a first hydraulic control one-way valve and a second hydraulic control one-way valve to pass through an oil return cavity, and locking a tie rod cylinder;
step S9: synchronous with step S8, calculating the deviation between the left and right side wheels and the target rotation angle;
step S10: the controller sends command signals to the servo motor and the electromagnetic reversing valve according to the deviation between the actual rotation angle of the left wheel and the target rotation angle to control the left and right steering power cylinders to stretch and retract so as to reach the target rotation angle;
preferably, angular velocity feedforward-angle feedback control is used to improve the switching accuracy of the electromagnetic directional valve, left turn is set to positive, a deviation angle between a target turning angle and an actual turning angle of a left steering wheel is used as a feedback signal, the target angular velocity is used as a feedforward signal, the sum of the feedback signal and the feedforward signal is used as a control signal, the control signal is larger than 0, the directional valve works in a left position, the control signal is equal to 0, the directional valve works in a middle position, the control signal is smaller than 0, and the directional valve works in a right position. The control signal function is as follows:
U＝(θ q -θ s )+ω q
wherein U is a control signal, θ q For the target rotation angle theta s For the actual rotation angle omega q Is the target angular velocity.
The foregoing description is only of the preferred embodiments of the invention, and all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (10)
1. The pump control main drive tie rod auxiliary valve control electrohydraulic steering system is characterized in that: the system comprises a main driving system of a variable-rotation-speed pump driving double-steering power-assisted cylinder, a tie rod auxiliary valve control system and an electronic control system; the main driving system of the variable-rotation-speed pump driving double-steering booster cylinder is a pump control system, the left and right steering booster cylinders are controlled through a servo motor pump unit and a steering booster cylinder valve group, and one flow is split to control the tie rod auxiliary valve control system; the auxiliary valve control system of the tie rod is a valve control system, the tie rod cylinder with a large cavity and a small cavity is controlled through the valve group of the tie rod cylinder and the locking device, and the auxiliary main driving system is used for controlling the corners of the left wheel and the right wheel; the electronic control system outputs control instructions to control the rotation angles of the left wheel and the right wheel in real time according to the input target rotation angle signals and the signals of the left wheel angle sensor and the right wheel angle sensor.
2. The pump-controlled primary drive tie rod assisted valve controlled electro-hydraulic steering system of claim 1, wherein: the main driving system of the variable-rotation-speed pump-driven double-steering power-assisted cylinder comprises a servo motor pump unit, a flowmeter, a steering power-assisted cylinder valve group, a left steering power-assisted cylinder and a right steering power-assisted cylinder; the first working oil way formed by the rodless cavity of the left steering power-assisted cylinder and the rod-free cavity of the right steering power-assisted cylinder is connected with the working oil port A of the electromagnetic reversing valve, and the second working oil way formed by the rod-free cavity of the left steering power-assisted cylinder and the rod-free cavity of the right steering power-assisted cylinder is connected with the working oil port B of the electromagnetic reversing valve; the P port of the electromagnetic reversing valve is connected with the oil inlet oil way, and the T port of the electromagnetic reversing valve is connected with the oil tank.
3. The pump-controlled primary drive tie rod assisted valve controlled electro-hydraulic steering system of claim 2, wherein: the servo motor pump unit consists of a servo motor and a constant displacement pump and is used as a pump source of a main driving system of the variable-rotation-speed pump driving double-steering booster cylinder; the pressure and flow of the main driving system are controlled by a servo motor pump unit, the direction is controlled by an electromagnetic reversing valve, the servo motor pump unit adjusts the rotating speed of a servo motor under the control of a controller so as to adapt to the change of working pressure and provide flow according to the requirement, and the main driving system also comprises four oil supplementing overflow valve groups which are respectively connected with four working oil ways in series; the oil supplementing overflow valve group is formed by connecting an overflow valve and a one-way valve in parallel.
4. The pump-controlled primary drive tie rod assisted valve controlled electro-hydraulic steering system of claim 1, wherein: the tie rod auxiliary valve control system comprises a tie rod cylinder valve group, a large cavity tie rod cylinder, a small cavity tie rod cylinder and a locking device; the large cavity working oil way of the large and small cavity transverse pull rod cylinder is connected with an A port of the servo proportional valve, the small cavity working oil way is connected with a B port of the servo proportional valve to form a third working oil way and a fourth working oil way respectively, and the locking device is positioned at the small cavity end of the large and small cavity transverse pull rod cylinder; the P port of the servo proportional valve is connected with an oil inlet oil way, and the T port of the servo proportional valve is connected with an oil tank; the tie rod auxiliary valve control system shares a pump source with the main drive system.
5. The pump-controlled, primary drive tie-bar assisted valve-controlled, electro-hydraulic steering system of claim 4, wherein: a branch of flow is separated from the main driving system, and a servo proportional valve is adopted to control the transverse pull rod cylinder; the large-small cavity tie rod cylinder is a double-rod-outlet cylinder optimally designed by structural parameters; the working areas of rod cavities on two sides of the transverse pull rod cylinder are unequal, and a locking device is connected to the small cavity end cover.
6. The pump-controlled, primary drive tie-bar assisted valve-controlled, electro-hydraulic steering system of claim 5, wherein: the method comprises the steps of optimizing structural parameters of a large-and-small-cavity tie rod cylinder by adopting a multi-objective optimization method based on a genetic algorithm, selecting driving power and steering driving force as optimization targets, taking pressure and flow parameters of a tie rod auxiliary valve control system as constraint conditions, taking area of the large-and-small-cavity, cylinder diameter, rod diameter and stroke structural parameters as optimization parameters, and constructing a multi-objective optimization model of the large-and-small-cavity hydraulic cylinder, wherein the multi-objective optimization model of the large-and-small-cavity hydraulic cylinder is as follows:
wherein P is driving power; f is steering driving force; x is X 1 ,…,X n The optimization parameters of the hydraulic cylinders with the large and small cavities are adopted;
respectively taking the minimum and the maximum values of the ith constraint condition; />
Respectively taking the minimum value and the maximum value of the ith optimization parameter, and constructing a multi-objective optimization genetic algorithm fitness function for the structural parameters of the large and small cavity hydraulic cylinders by utilizing a genetic algorithm as follows:
wherein θ i Fitness for the ith individual; a. b is an adaptability parameter used for adjusting the weight of the driving power and the steering driving force in the optimization; p (P) i 、F i Predicted values of the i-th individual driving power and the steering driving force, respectively; the theta is as follows i The smaller the driving power corresponding to the individual, the larger the steering driving force.
7. The pump-controlled primary drive tie-bar assisted valve-controlled electro-hydraulic steering system of claim 5, wherein: the locking device forms wedge-shaped locking through the conical locking ring and the conical sleeve to form mechanical self-locking; the control port of the locking device is connected with a first reversing ball valve, the first reversing ball valve is electrified, and the locking device and the hydraulic lock work together to enable the large and small cavity transverse pull rod cylinder to be self-locking.
8. The pump-controlled primary drive tie rod assisted valve controlled electro-hydraulic steering system of claim 1, wherein: the hydraulic control one-way valve and the reversing ball valve form an external control type hydraulic lock which is respectively connected with an A port and a B port of the servo proportional valve and the electromagnetic reversing valve in series; the first reversing ball valve and the second reversing ball valve are two-position three-way valves, and the hydraulic lock is locked by the electricity of the reversing ball valves.
9. The control method of the pump control main drive tie rod auxiliary valve control electro-hydraulic steering system is characterized in that the pump control main drive tie rod auxiliary valve control electro-hydraulic steering system is adopted according to the claims 1-8: the method comprises the following steps:
step S1: the electrohydraulic servo steering system inputs left and right target rotation angle signals of a controlled steering axle to the controller;
step S2: judging whether locking of the large-small cavity transverse pull rod cylinder is needed or not: if not, jumping to the step S3; if necessary, jumping to step S8;
step S3: the controller takes the target rotation angle signals of the left and right wheels as two control targets to control the system;
step S4: detecting actual rotation angles of left and right wheels of a controlled steering axle, and respectively calculating deviation between the actual rotation angles of the left and right wheels and a target rotation angle;
step S5: according to the deviation signal of the target rotation angle of the left wheel and the current rotation angle, the controller sends a signal to the servo motor and the electromagnetic directional valve to control the work of the servo motor and the electromagnetic directional valve; controlling the servo proportional valve to work according to a deviation signal of a target rotation angle of the right wheel and a current rotation angle;
step S6: the servo proportional valve outputs a hydraulic signal to control the expansion and contraction of the large-cavity and small-cavity transverse pull rod cylinder, and the servo motor pump unit and the electromagnetic reversing valve control the left and right side steering power cylinders to expand and contract together so that the left or right wheels reach a target rotation angle;
step S7: judging whether the left wheel rotation angle deviation signal is larger than a critical rotation angle threshold value of 0.2 degrees: if yes, jumping to the step S3; if not, jumping to the step S8;
step S8: setting a servo proportional valve to be in a middle position, powering a first reversing ball valve, leading oil of a first hydraulic control one-way valve and a second hydraulic control one-way valve to pass through an oil return cavity, and locking a tie rod cylinder;
step S9: synchronous with step S8, calculating the deviation between the left and right side wheels and the target rotation angle;
step S10: and sending command signals to the servo motor and the electromagnetic reversing valve according to the deviation controller between the actual rotation angle of the left wheel and the target rotation angle to control the left and right steering power cylinders to stretch and retract so as to achieve the target rotation angle.
10. The control method of the pump-controlled main drive tie rod auxiliary valve-controlled electro-hydraulic steering system according to claim 9, wherein: the servo motor changes the rotating speed of the motor through a voltage control signal so as to adjust the output flow and pressure of the constant displacement pump; the electromagnetic directional valve is controlled by using angular velocity feedforward-angle feedback control, the left turn is set to be positive, the deviation angle between the target turning angle and the actual turning angle of the left steering wheel is used as a feedback signal, the target angular velocity is used as a feedforward signal, the sum of the feedback signal and the feedforward signal is used as a control signal, and the function of the control signal is as follows:
U＝(θ q -θ s )+ω q
wherein U is a control signal, θ q For the target rotation angle theta s For the actual rotation angle omega q Is the target angular velocity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310469334.2A CN116331342A (en) | 2023-04-27 | 2023-04-27 | Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310469334.2A CN116331342A (en) | 2023-04-27 | 2023-04-27 | Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116331342A true CN116331342A (en) | 2023-06-27 |
Family
ID=86882509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310469334.2A Pending CN116331342A (en) | 2023-04-27 | 2023-04-27 | Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116331342A (en) |
-
2023
- 2023-04-27 CN CN202310469334.2A patent/CN116331342A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105857393B (en) | The differential boost line draining pressure forward method of full wheel independent electric drive articulator | |
| CN112550444B (en) | Energy-saving type electro-hydraulic power-assisted steering system for heavy vehicle and control method | |
| CN104443025B (en) | Electro-hydraulic servo pure rolling steering system for multi-axis vehicle and control method | |
| CN1818382A (en) | Closed electrohydraulic controlling system | |
| CN109630504B (en) | Oil inlet and outlet independent control system with pressure compensation function | |
| CN105253192A (en) | Automobile electric hydraulic power steering system control method | |
| CN113928412B (en) | Electro-hydraulic composite steering system and electro-hydraulic decoupling control method | |
| CN110147580A (en) | Consider the automatically controlled steering system power-assisted current characteristic curve design method of hybrid power of energy consumption | |
| CN104608819A (en) | Multi-axle steering system for multi-axle vehicle and multi-axle vehicle | |
| CN116331342A (en) | Pump control main drive transverse pull rod auxiliary valve control electrohydraulic steering system and control method | |
| CN112918552B (en) | Heavy multi-axle vehicle steering system based on hydraulic transformer and control method thereof | |
| CN110606078A (en) | Multi-shaft distributed electrically-driven vehicle steering control method | |
| CN212148295U (en) | Hydraulic suspension system and multi-axis flat car | |
| CN116890909A (en) | Electro-hydraulic steering system for switching volume/throttle speed regulation modes and control method | |
| CN114655306B (en) | Heavy vehicle electrohydraulic servo steering system and control method capable of inhibiting overshoot | |
| CN206589959U (en) | A kind of multi-mode composite turning genealogical classification controller | |
| CN110539798A (en) | Independent differential steering method of distributed drive articulated vehicle | |
| CN114771649B (en) | Load port independent control type electrohydraulic servo steering system and control method thereof | |
| CN107503997A (en) | Back pressure and the double actuator systems of power matching hydraulic hybrid regulation and control | |
| CN114537344A (en) | Hydraulic braking power control system and method | |
| Yang et al. | Investigation of Energy-saving and Dynamic Response of Direct Drive Electro-hydraulic Steering System for Articulated Trucks | |
| CN107448440A (en) | Back pressure and the electric-hydraulic combined regulation and control multi executors system of power oil | |
| CN106585714B (en) | A kind of multi-mode composite turning genealogical classification controller and its control method | |
| CN107701531B (en) | Power and the electro-hydraulic combination of rigidity and flexibility of back pressure oil regulate and control multi executors system | |
| CN117702856A (en) | Electro-hydraulic steering accurate control device and method for engineering machinery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |