CN102372022A - Multi-axle vehicle as well as electro-hydraulic servo steering system and steering control method thereof - Google Patents

Abstract

The invention discloses an electro-hydraulic servo steering system for a multi-axle vehicle, a steering control method and a multi-axle vehicle with the steering system. The electro-hydraulic servo steering system includes: a hydraulic steering system including a variable displacement pump, at least Steering power cylinders on each steering axle, and servo proportional valves used to control the direction of the oil circuit and flow adjustment, electronic control system, which includes a lower controller that is connected with the servo proportional valve signals of each subsequent steering axle and forms a closed-loop control , the upper-level controller used to calculate the target angles of the subsequent steering axles according to the angle of the first axle and the steering mode. In the present invention, the electronic control system of the two-stage controller is preferred, so that the servo proportional valve and the lower controller form a small closed loop, and the high-response lower controller cooperates with the servo proportional valve to ensure the accuracy, while the programmable logic controller performs the main calculation Work and send to each lower controller corner command. The invention has the advantages of simple structural arrangement, safety and reliability, and good manipulation stability.

Description

Multi-axle vehicle electro-hydraulic servo steering system, steering control method and multi-axle vehicle

technical field

The invention relates to a steering system and a steering control method of a multi-axle vehicle, and also relates to a multi-axle vehicle with the electro-hydraulic servo steering system.

Background technique

The steering system of a vehicle is directly related to the safety, maneuverability and handling stability of the vehicle.

With the development of heavy-duty vehicles, the load of the whole vehicle is getting bigger and bigger, which requires an increase in the number of axles, and the body is getting longer and longer. In order to reduce the minimum steering radius and driving resistance, and reduce tire wear, on the one hand, the number of steering bridges must be increased, and on the other hand, the steering wheels are required to coordinate with each other when turning.

Traditional multi-axle vehicles use a hydraulic power-assisted rod system transmission and steering system, which occupies space for the layout of the frame, and the rod system is easily deformed, and the vehicle may swing and have poor stability when driving at high speed. In recent years, with the rapid development of electro-hydraulic technology, the electro-hydraulic control steering system has been used in multi-axle vehicles. However, due to the limitation of the response frequency of the general electro-hydraulic proportional solenoid valve, the steering error is relatively large, especially The dynamic error is large, which greatly affects the steering performance and tire life.

In view of this, it is urgent to develop a new steering system, which puts forward higher requirements for various performance parameters in the multi-axis steering system, so as to ensure the safety, maneuverability and handling stability of the vehicle.

Contents of the invention

The purpose of the present invention is to provide a steering system of a multi-axle vehicle, which has a simple structure and arrangement, is safe and reliable, and has good handling stability. Another purpose of the present invention is to provide a steering control method for a multi-axle vehicle. It is also an object of the invention to provide a multi-axle vehicle with said steering system.

To this end, the present invention provides an electro-hydraulic servo steering system for a multi-axle vehicle. The multi-axle vehicle includes a first axle and rear steering axles. The electro-hydraulic servo steering system includes: a hydraulic steering system , which includes a variable pump that provides an oil source, a power steering cylinder installed at least on each of the rear steering axles, and a main oil circuit between the variable pump and the power steering cylinder for controlling the direction of the oil circuit and Servo proportional valve for flow adjustment, electronic control system, used to calculate the required target angle of rotation of each rear steering axle according to the rotation angle signal and steering mode of the first axle, and to the said servo proportional valve of each rear steering axle The valve outputs a command signal corresponding to the target rotation angle, and at the same time adjusts the command signal in real time according to the rotation angle signals fed back by the subsequent steering axles.

Further, the above-mentioned hydraulic steering system further includes a hydraulically controlled one-way valve arranged on the main oil circuit, wherein a solenoid valve is arranged on the hydraulically controlled pipeline of the hydraulically controlled one-way valve, and the solenoid valve is signal-connected to the electronic control system.

Further, the above-mentioned hydraulic steering system also includes a precision oil filter arranged on the main oil circuit.

Further, the above-mentioned electronic control system includes: a lower-level controller that is connected with the servo proportional valve signals of each subsequent steering axle and forms a closed-loop control, and is connected with each lower-level controller with a signal, and is used to calculate the first axle rotation angle and the steering mode according to the first axle. The upper controller of the target rotation angle of each steering axle at the rear, and a plurality of angular displacement sensors for detecting the rotation angle signals of each steering axle.

Further, the above-mentioned upper controller is also used for displaying vehicle status and/or fault alarming according to the rotation angle signal fed back by the angular displacement sensor.

Further, the above-mentioned upper controller is a programmable logic controller.

According to another aspect of the present invention, a multi-axle vehicle having the above-mentioned electro-hydraulic servo steering system is also provided.

The present invention also provides a steering control method for a multi-axle vehicle, which includes the following steps: detecting the rotation angles of the first axle of the vehicle and each subsequent steering axle, and transmitting the rotation angle signal of the first axle to the upper controller, wherein, Each rear steering axle is equipped with a servo proportional valve for controlling the steering power cylinder and a lower controller for controlling the servo proportional valve; target rotation angle, and output the corresponding target rotation angle control signal to each lower controller; Adjust the command signal in real time.

Further, the above-mentioned upper controller is a programmable logic controller or a single-chip microcomputer, and the response frequency of the lower controller is adapted to the response frequency of the servo control valve.

Further, the above method also includes the step of using the steering angle signal fed back by the steering axle for vehicle status display and/or failure alarm.

Compared with the general rod connection and electro-hydraulic steering scheme, the structure of the steering system of the present invention is simplified, and the steering control is realized by using the servo proportional valve, and no pressure difference compensation valve and diverter valve are added, and it is realized with as few components as possible. High performance makes the system relatively safe and reliable; the use of servo proportional valves has the great advantage of fast response and is easy to achieve precise control; in addition, the use of variable displacement pumps not only meets the flow requirements of the engine at idle speed, but also saves energy.

Compared with the general electronic control system, the present invention preferably adopts the electronic control system of two-stage controller, the servo proportional valve and the lower controller form a small closed loop, the lower controller with high frequency response cooperates with the servo proportional valve to ensure the accuracy, the upper controller A controller such as a programmable logic controller (or called PLC or PLC controller) performs the main calculation work, and sends an instruction signal corresponding to the target rotation angle to each lower controller (or called a single-axis closed-loop controller) .

According to the electro-hydraulic servo steering system of the multi-axle vehicle of the present invention, multiple steering modes can be flexibly used, the operability is strong, and the steering mode is convenient to expand.

In addition to the purposes, features, and advantages described above, other purposes, features, and advantages of the present invention will be further described in detail with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the description serve to explain the principle of the invention.

Fig. 1 shows a schematic diagram of a hydraulic steering system of an electro-hydraulic servo steering system of a multi-axle vehicle according to the present invention;

FIG. 2 shows a schematic diagram of the power steering cylinder of the hydraulic steering system shown in FIG. 1 being installed on the steering axle.

Fig. 3 shows the electronic control of the electrohydraulic servo steering system of the multi-axle vehicle according to the present invention

a schematic diagram of the control system; and

Fig. 4 shows a control logic block diagram for implementing steering axle steering of the multi-axle vehicle electro-hydraulic servo steering system according to the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the claims.

The electro-hydraulic servo steering system of a multi-axle vehicle of the present invention includes a hydraulic steering system and an electronic control system, the hydraulic steering system is shown in Figures 1 and 2, and the electronic control system is shown in Figure 3 . In the present invention, the steering control method of the first axle is not limited, and the traditional steering control method can be adopted, such as the method of hydraulic power assist plus mechanical guidance, or the method of directly driving the trapezoidal arm of the steering axle by the steering power cylinder of the present invention . The present invention intends to make the following steering axles track the first axle turning angle quickly, accurately and reliably. The electro-hydraulic servo steering system of the multi-axle vehicle of the present invention will be described in detail below with reference to FIGS. 1 to 3 .

As shown in Figures 1 and 2, the hydraulic steering system includes: two steering power cylinders 6 installed between the vehicle axle 30 and the steering knuckle arms 21 and 22 of the trapezoidal arm 20 of the steering axle, providing oil sources to the two steering power cylinders 6 The variable displacement pump 4, and the servo proportional valve 5 that controls the action of the power steering cylinder 6 to realize steering.

In addition, the hydraulic steering system may also include a hydraulic control check valve 10 and a precision oil filter 8 arranged on the main oil circuit of the two steering booster cylinders 6 , wherein a solenoid valve 9 is provided on the control oil circuit of the hydraulic control check valve.

The rod chamber of one oil cylinder of the two power steering cylinders 6 communicates with the rodless chamber of the other oil cylinder. When one oil cylinder stretches out, the other oil cylinder retracts to realize coordinated action. Using two power steering cylinders increases the Axle steering assist and effectively reduce vehicle steering hydraulic pressure requirements, providing conditions for energy saving and layout space saving.

The servo proportional valve 5 has a flow adjustment function and a reversing function, which can be obtained from the market. Through the reversing function of the servo proportional valve 5, the direction of the oil circuit can be controlled to realize the extension and retraction of the power steering cylinder and the adjustment of the oil volume. The function can change the amount of oil supplied to the power steering cylinder. By adjusting the amount of oil supplied to the power steering cylinder, the action of the power steering cylinder can be controlled, thereby realizing precise control of the steering angle of the steering axle.

In the present invention, the electronic control system is used to calculate the target rotation angle required by the subsequent steering axles according to the rotation angle signal of the first axle and the steering mode, and output to the servo proportional valves of the subsequent steering axles corresponding to the target rotation angle At the same time, the command signal is adjusted in real time according to the angle signal fed back by each steering axle.

Here, the steering mode is a mode selected or set by the user, such as normal steering, rear axle lock, crab steering, and the like.

The electronic control system of the present invention preferably adopts a two-stage controller, as shown in Figure 3, which includes: a lower controller (or called a single-axis) that is connected with the servo proportional valve signals of each steering axle at the rear and forms a single-axis closed-loop control Closed-loop controller) 3, connected with each lower controller 3 signals, for calculating the upper controller such as programmable logic controller 2 (or being called as programmable logic controller 2) of the target angle of rotation of each rear steering axle according to the angle signal of the first bridge and the steering pattern PLC controller), and the angular displacement sensors 1 installed on each steering axle (comprising the first axle and the rear steering axles), wherein each angular displacement sensor is respectively connected with the upper controller and the corresponding lower controller signal, It is used to detect the actual rotation angle signal of each steering axle.

The lower controller 3 is also signal-connected with the solenoid valve 9 for controlling the hydraulic control check valve 10 . When the solenoid valve 9 is energized, the control oil source of the hydraulic control check valve 10 is cut off, and the power steering cylinder 6 is locked; when the solenoid valve 9 is de-energized, the hydraulic control check valve 10 is opened, and the servo proportional valve 5 can control the power steering Cylinder 6 moves.

The advantages of the electronic control system using two-stage controllers are: the servo proportional valve 5 and the lower controller 3 form a small closed loop, and the lower controller 3 with high frequency response cooperates with the servo proportional valve 5 with high frequency response to ensure dynamic accuracy and Steady-state accuracy, the upper controller 2 performs the main calculation work, and sends the target rotation angle command signal to each lower controller 3 .

The steering control method of the multi-axle vehicle of the present invention includes the following steps: detecting the rotation angles of the first axle and the rear steering axles of the vehicle, and transmitting the rotation angle signal of the first axle to the upper controller, wherein the rear steering axles are set There are servo proportional valves used to control the steering power cylinder and lower controllers used to control the servo proportional valves; the upper controller calculates the target rotation angle required by each rear steering axle according to the steering mode and the rotation angle signal of the first axle, and will correspondingly The target rotation angle control signal is output to each lower controller; and each lower controller sends an instruction signal to the corresponding servo proportional valve according to the target rotation angle control signal of the upper controller, and adjusts the instruction signal in real time according to the rotation angle signal fed back by the steering axle.

The electro-hydraulic servo steering system and the steering control method of the present invention will be described below with reference to FIGS. 1 to 4 .

Referring to FIG. 4 , when the vehicle is turning, the steering wheel is turned, and the angle signal is detected by the angular displacement sensor 1 installed on the first bridge, and the signal is sent to the host controller 2 .

The upper controller 2 calculates the required target rotation angle of each axis according to the steering mode selected by the user and the first axle rotation angle signal, and then outputs it to the lower controller 3 through the analog output port.

After receiving the rotation angle control signal from the upper controller 2, the lower controller 3 controls the servo proportional valve 5, and the hydraulic power is provided by the variable pump 4, and then drives the power steering cylinder 6 to drive the steering axle 7 (that is, a certain rear steering axle) to realize steering At the same time, the actual rotation angle of the steering axle 7 is detected by the angular displacement sensor 1, the lower controller 3 compares the rotation angle feedback signal with the instruction signal of the upper controller 2, and adjusts the control signal of the servo proportional valve 5 in real time according to the comparison result until the feedback signal until it is equal to the command signal.

Through the closed-loop control of the single-axis rotation angle, the 7 rotation angles of the rear steering axles can quickly, accurately and reliably track the rotation angle of the first axle.

Since the angle of rotation can be flexibly set in the upper controller 2, it is convenient to realize multiple steering modes, including normal steering, rear axle locked, crab steering and other modes. The rotation angle signals of each steering axle 7 in the back are not only transmitted to the lower controller 3 for comparison, but also to the upper controller 2, and the upper controller 2 performs vehicle status display and/or failure according to the rotation angle signals fed back by these angular displacement sensors 1 Alarm (as shown in Figure 3), in order to realize real-time monitoring and fault judgment.

The steering system and steering control method of the present invention get rid of the unfavorable factors of steering rod deformation, assembly error and cumulative error in the original rod-connected steering system. The closed-loop control and the micro-control of the servo proportional valve ensure the steady-state accuracy, and the response speed of the servo proportional valve also ensures the dynamic accuracy. The engine speed changes in a wide range when the vehicle is running, and the variable pump is used to ensure sufficient oil supply to the system at idle speed, and it is relatively energy-saving.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. 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 (10)

1. electro-hydraulic servo steering swivel system that is used for multiple-axle vehicle, said multiple-axle vehicle comprise first bridge and in the back each steeraxle, it is characterized in that said electro-hydraulic servo steering swivel system comprises:

Hydrostatic steering system; It comprises controllable capacity pump that oil sources is provided, is installed on said steering jack and the servo proportion that is used for control oil channel trend and flow regulating that on the working connection between said controllable capacity pump and the steering jack, is provided with on each steeraxle of back at least, and

Electronic control system; Be used for according to the angular signal of first bridge with turn to mode computation to go out at the required target rotation angle of each steeraxle of back; And to the said output of said servo proportion and the corresponding command signal of said target rotation angle of each steeraxle in the back, simultaneously according to said in the back the said command signal of angular signal real-time regulated of each steeraxle feedback.

2. electro-hydraulic servo steering swivel system according to claim 1; It is characterized in that; Said hydrostatic steering system also is included in the hydraulic control one-way valve that is provided with on the said working connection; Wherein, the hydraulic control pipeline of said hydraulic control one-way valve is provided with electromagnetic valve, and said electromagnetic valve is connected with said electronic control system signal.

3. electro-hydraulic servo steering swivel system according to claim 1 is characterized in that said hydrostatic steering system also is included in the precise oil filter that is provided with on the said working connection.

4. according to each described electro-hydraulic servo steering swivel system in the claim 1 to 3; It is characterized in that; Said electronic control system comprises: go up level controller; Following level controller, and a plurality of angular-motion transducers that are used to detect the angular signal of each said steeraxle, wherein; The servo proportion of said each steeraxle in the back is connected with a next controller signals and forms closed loop control, and said upward level controller is connected, is used for according to the said first bridge corner and turns to the said target rotation angle at each steeraxle of back of mode computation with each said the next controller signals.

5. electro-hydraulic servo steering swivel system according to claim 5 is characterized in that, the said level controller of going up also is used for carrying out vehicle-state demonstration and/or fault alarm according to the angular signal of said angular-motion transducer feedback.

6. electro-hydraulic servo steering swivel system according to claim 5 is characterized in that, said upward level controller is a programmable logic controller (PLC).

7. multiple-axle vehicle that have according to each described electro-hydraulic servo steering swivel system in the claim 1 to 6.

8. the rotating direction control method of multiple-axle vehicle is characterized in that, may further comprise the steps:

Detect vehicle first bridge and at the corner of each steeraxle of back; And send the angular signal of first bridge to level controller; It is wherein, said that each steeraxle is provided with the servo proportion and the following level controller that is used to control said servo proportion that is used to control steering jack in the back;

The said level controller basis that goes up turns to the angular signal calculating of pattern and said first bridge said at the required target rotation angle of each steeraxle of back, and exports corresponding target rotation angle control signal to each said level controller down; And

Each said down level controller sends command signal according to the said target rotation angle control signal of going up level controller to corresponding servo proportion, and according to the said command signal of angular signal real-time regulated of said steeraxle feedback.

9. the rotating direction control method of multiple-axle vehicle according to claim 8 is characterized in that, said upward level controller is programmable logic controller (PLC) or micro controller system, and the response frequency of said level controller down and the response frequency of said servo operated valve are suitable.

10. the rotating direction control method of multiple-axle vehicle according to claim 8 is characterized in that, also comprises the step that the angular signal of said steeraxle feedback is used for vehicle-state demonstration and/or fault alarm.

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