Engineering machinery electro-hydraulic steering flexible safety control device and method

Abstract

An engineering machinery electro-hydraulic steering flexible safety control device and method. The device comprises a first controller (3), an electric control handle (2), an electro-hydraulic steering unit (1), a steering cylinder (5) and an electric control pump (4); the electric control handle (2) is connected to the first controller (3) and sends a steering request signal to the first controller (3), so that the first controller (3) generates a CAN signal or a PWM signal; the electro-hydraulic steering unit (1) comprises an electric control steering module (1.1) and a reversing valve (1.2) which are connected to each other, the electric control steering module (1.1) is further connected to the first controller (3) separately by means of a CAN signal line and a PWM signal line, and the reversing valve (1.2) is further communicated with the steering cylinder (5); the electric control pump (4) is separately connected to the first controller (3) and the reversing valve (1.2); and the electric control steering module (1.1) responds to the CAN signal or the PWM signal sent by the first controller (3), and outputs a pilot pressure on the basis of the CAN signal or the PWM signal to actuate the reversing valve (1.2) to shift. In the device, when a fault has occurred in the CAN signal line, the PWM signal line takes over the steering request signal, thereby guaranteeing that a vehicle continues to steer and achieving the safety of vehicle steering.

Description

A flexible safety control device and method for electro-hydraulic steering in engineering machinery Technical Field

[0001] This invention belongs to the field of vehicle steering control technology, specifically relating to a flexible safety control device and method for electro-hydraulic steering of engineering machinery. Background Technology

[0002] The field of industrial control is now developing towards informatization, intelligence, and networking. As a key system of construction machinery, the steering system has strict requirements for safety. With the increasing demands for the stability, safety, and comfort of construction machinery vehicles, in order to ensure the reliability of vehicle steering and driving comfort, large construction machinery adopts electric control levers to control the steering system and uses high-performance, high-transmission-efficiency CAN bus communication. How to ensure that steering stability and safety can still be maintained when the vehicle steering control signal fails has become a technical challenge faced by construction machinery both domestically and internationally.

[0003] Chinese invention patent CN113911207A discloses a steering system with automatic centering and emergency start functions. A power source provides the required pressure and flow rate for the system. A nested steering cylinder is the actuator used to achieve vehicle steering and centering. The nested steering cylinder is controlled by a proportional steering control valve group and includes a centering chamber, an extension chamber, and a retraction chamber. A centering accumulator provides centering power to the nested steering cylinder through a centering accumulator control valve group. An emergency accumulator provides energy when the power source cannot provide the working pressure required for vehicle steering. When the power source malfunctions, the emergency accumulator continues to provide power to the vehicle steering system, enabling emergency steering. It also addresses emergency steering issues when the steering control signal malfunctions.

[0004] Chinese invention patent CN114506386B discloses a control method for emergency steering of a vehicle, a steering assist system, and a dump truck. The control method for emergency steering is used in a steering assist system, which includes an electro-hydraulic steering assembly, comprising an electro-hydraulic steering gear and a power assist motor. The control method includes: acquiring vehicle speed signals and vehicle engine operating status signals; issuing an emergency steering assist command based on the vehicle speed signals and / or engine operating status signals; responding to the emergency steering assist command by controlling the power assist motor to output an emergency steering current; and controlling the electro-hydraulic steering gear to output an emergency steering force based on the emergency steering current. This enables the vehicle to perform emergency steering, improving the reliability and safety of emergency steering.

[0005] It is evident that most existing vehicle emergency steering control methods employ an emergency pump or emergency accumulator to provide power to the steering system when the power source fails, thereby enabling emergency steering. Alternatively, a motor can be added to the steering gear to assist steering when hydraulic power steering fails, thus achieving emergency steering. However, it is not explained how to achieve emergency steering when the control signal in the electronically controlled hydraulic steering system malfunctions (e.g., it cannot be sent correctly).

[0006] Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes a flexible safety control device and method for electro-hydraulic steering in engineering machinery. After CAN bus fault verification, when a CAN signal malfunctions, PWM takes over the control signal to ensure the vehicle continues to steer, thus achieving vehicle steering safety.

[0008] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0009] In a first aspect, the present invention provides a flexible safety control device for electro-hydraulic steering of engineering machinery, comprising a first controller, an electric control handle, an electro-hydraulic steering unit, a steering cylinder, and an electric control pump;

[0010] The electric control handle is connected to the first controller and sends a steering request signal to the first controller, causing the first controller to generate a CAN signal or a PWM signal.

[0011] The electro-hydraulic steering unit includes an electronically controlled steering module and a reversing valve connected together. The electronically controlled steering module is also connected to the first controller via a CAN signal line and a PWM signal line, respectively. The reversing valve is also connected to the steering cylinder.

[0012] The electrically controlled pump is connected to the first controller and the reversing valve respectively;

[0013] The electronic steering module responds to the CAN signal or PWM signal sent by the first controller, and outputs pilot pressure according to the CAN signal or PWM signal to drive the reversing valve to switch.

[0014] In conjunction with the first aspect, optionally, the electronic steering module includes: a second controller, a temperature sensor, a current acquisition device, and an electro-proportional valve; the electro-proportional valve is also connected to the directional valve;

[0015] The temperature sensor is used to collect the actual oil temperature of the proportional valve in the electronic steering module and send it to the second controller. The second controller sends the actual oil temperature of the proportional valve to the first controller via the CAN signal line.

[0016] The current acquisition device is used to acquire the actual current value of the electro-proportional valve in the electronic steering module and send it to the second controller. The second controller then sends the actual current value of the electro-proportional valve to the first controller via the CAN signal line.

[0017] In conjunction with the first aspect, optionally, the electro-hydraulic steering flexible safety control device for engineering machinery further includes a displacement sensor, which is connected to the first controller and the second controller respectively; the first controller includes a CAN bus verification module and a bus displacement module;

[0018] The CAN bus verification module is connected to the second controller;

[0019] When the CAN bus verification module verifies the CAN signal line through the CAN bus based on the signal sent by the second controller, indicating that the CAN signal line is in a normal state, the bus displacement module calculates the target displacement value of the directional valve spool based on the steering request signal, and sends the target displacement value of the directional valve spool to the second controller in the form of a CAN signal. The second controller, based on the received target displacement value of the directional valve spool, compares the actual displacement value of the directional valve spool collected by the displacement sensor with the target displacement value of the directional valve spool, calculates the displacement error value, performs PID adjustment based on the displacement error value, outputs a compensated current value, and uses the compensated current value to control the electro-proportional valve in the electronic steering module to output pilot pressure, thereby pushing the directional valve to switch directions and completing the closed-loop control of the directional valve spool displacement.

[0020] In conjunction with the first aspect, the first controller may optionally further include an emergency state analysis module and a steering valve control module;

[0021] When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a fault state, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. Based on the steering request signal, the steering valve control module calculates the target displacement value of the directional valve core and performs position error calculation with the actual displacement value of the directional valve core sent by the displacement sensor. Based on the displacement error value, PID control is performed to calculate the target current of the directional valve. Then, based on the actual current value of the directional valve, the target duty cycle required for the PWM signal is calculated, and the PWM signal is sent to the electro-proportional valve in the electronic steering module. The electro-proportional valve in the electronic steering module is controlled to output pilot pressure to push the directional valve to switch directions. The closed-loop control of the directional valve core displacement is completed based on the actual displacement value of the directional valve core collected by the displacement sensor.

[0022] In conjunction with the first aspect, optionally, when the displacement sensor malfunctions, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. The steering valve control module outputs a corresponding PWM signal according to the preset steering request signal and the target duty cycle required by the PWM signal, and controls the electro-proportional valve in the electronic steering module to output pilot pressure to push the reversing valve core to reverse.

[0023] In conjunction with the first aspect, optionally, the electric control handle outputs a steering request signal to the first controller, the first controller calculates the corresponding pump displacement adjustment signal based on the steering request signal, and performs real-time control of the electric control pump according to the pump displacement adjustment signal to complete the displacement adjustment.

[0024] In conjunction with the first aspect, optionally, the electric control handle is a dual-bus handle, which is connected to the first controller via an independent first CAN bus and a second CAN bus. When one of the buses fails, the other bus sends a steering control signal to the first controller one cycle later than the failed bus, ensuring the continuity of the CAN bus signal.

[0025] Secondly, the present invention provides a flexible safety control method for electro-hydraulic steering of engineering machinery, comprising:

[0026] The electric control handle sends a steering request signal to the first controller, which then generates a CAN signal or a PWM signal.

[0027] The first controller adjusts the displacement of the electronically controlled pump based on the steering request signal.

[0028] The electro-hydraulic steering unit utilizes an electro-hydraulic steering module to receive a CAN bus signal sent by the first controller via a CAN signal line or a PWM signal sent via a PWM signal line. Based on the CAN signal or PWM signal, it outputs pilot pressure to drive the directional valve connected to the electro-hydraulic steering unit to reverse, thereby causing the steering cylinder connected to the directional valve to operate.

[0029] In conjunction with the second aspect, optionally, the electronic steering module includes: a second controller, a temperature sensor, a current acquisition device, and an electro-proportional valve; the electro-proportional valve is also connected to the directional valve;

[0030] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0031] The actual oil temperature of the proportional valve in the electronic steering module is collected by a temperature sensor and sent to the second controller. The second controller then sends the actual oil temperature of the proportional valve to the first controller via a CAN signal line.

[0032] The actual current value of the electro-proportional valve in the electronic steering module is collected by a current acquisition device and sent to the second controller. The second controller then sends the actual current value of the electro-proportional valve to the first controller via a CAN signal line.

[0033] In conjunction with the second aspect, optionally, the first controller includes a CAN bus verification module and a bus displacement module; the CAN bus verification module is connected to the second controller;

[0034] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0035] The actual displacement value of the directional valve core is collected by a displacement sensor and sent to the first controller and the second controller.

[0036] When the CAN bus verification module verifies the CAN signal line through the CAN bus based on the signal sent by the second controller, indicating that the CAN signal line is in a normal state, the bus displacement module calculates the target displacement value of the directional valve spool based on the steering request signal, and sends the target displacement value of the directional valve spool to the second controller in the form of a CAN signal. The second controller, based on the received target displacement value of the directional valve spool, compares the actual displacement value of the directional valve spool collected by the displacement sensor with the target displacement value of the directional valve spool, calculates the displacement error value, performs PID adjustment based on the displacement error value, outputs a compensated current value, and uses the compensated current value to control the electro-proportional valve in the electronic steering module to output pilot pressure, thereby pushing the directional valve to switch directions and completing the closed-loop control of the directional valve spool displacement.

[0037] In conjunction with the second aspect, the first controller may optionally further include an emergency state analysis module and a steering valve control module;

[0038] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0039] When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a fault state, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. Based on the steering request signal, the steering valve control module calculates the target displacement value of the directional valve core and performs position error calculation with the actual displacement value of the directional valve core sent by the displacement sensor. Based on the displacement error value, PID control is performed to calculate the target current of the directional valve. Then, based on the actual current value of the directional valve, the target duty cycle required for the PWM signal is calculated, and the PWM signal is sent to the electro-proportional valve in the electronic steering module. The electro-proportional valve in the electronic steering module is controlled to output pilot pressure to push the directional valve to switch directions. The closed-loop control of the directional valve core displacement is completed based on the actual displacement value of the directional valve core collected by the displacement sensor.

[0040] In conjunction with the second aspect, optionally, the electro-hydraulic steering flexible safety control method for engineering machinery further includes:

[0041] When the displacement sensor malfunctions, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. The steering valve control module outputs a corresponding PWM signal according to the preset steering request signal and the target duty cycle required by the PWM signal, and controls the electro-proportional valve in the electronic steering module to output pilot pressure to push the reversing valve core to reverse.

[0042] In conjunction with the second aspect, optionally, the step of using the first controller to adjust the displacement of the electronically controlled pump based on the steering request signal specifically includes:

[0043] The electric control handle outputs a steering request signal to the first controller. Based on the steering request signal, the first controller calculates the corresponding pump displacement adjustment signal and performs real-time control of the electric control pump according to the pump displacement adjustment signal to complete the displacement adjustment.

[0044] In conjunction with the second aspect, optionally, the electric control handle is a dual-bus handle, which is connected to the first controller via an independent first CAN bus and a second CAN bus. The electro-hydraulic steering flexible safety control method for engineering machinery further includes:

[0045] When one of the buses fails, the other bus sends a steering control signal to the first controller one cycle later than the failed bus, ensuring the continuity of the CAN bus signal.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] 1. In this invention, the electronic steering module can receive CAN signals and PWM signals. When the CAN signal line fails, the PWM signal line takes over the control signal to ensure that the vehicle continues to steer and achieve vehicle steering safety.

[0048] 2. In this invention, a displacement sensor is installed in the electronic steering module, and a steering control module is adopted. When the CAN signal line fails, the target duty cycle of the PWM signal is accurately calculated based on the valve core position information of the directional valve, and the vehicle steering is controlled. This achieves seamless connection of flow when the CAN signal and PWM signal alternate, thereby realizing the flexibility and stability of vehicle steering.

[0049] 3. This invention employs a dual-bus handle. When the first CAN signal of the electric control handle fails, the second CAN signal can continue to send the same steering request signal (i.e., control signal), ensuring the continuity of the control signal. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0051] Figure 1 is a schematic diagram of the principle of an electro-hydraulic steering flexible safety control device for engineering machinery according to an embodiment of the present invention;

[0052] Figure 2 is a schematic diagram of an electronically controlled steering module according to an embodiment of the present invention;

[0053] Figure 3 is a partial schematic diagram of the principle of a first controller according to the present invention;

[0054] Figure 4 is a partial schematic diagram of the principle of a first controller according to the present invention;

[0055] Figure 5 is a flowchart of the steering valve core displacement control according to an embodiment of the present invention;

[0056] Wherein: 1-Electro-hydraulic steering unit; 2-Electro-controlled handle; 3-First controller; 4-Electro-controlled pump; 5-Steering cylinder; 1.1-Electro-controlled steering module; 1.2-Reversing valve. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may include different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0059] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0060] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

[0062] Example 1

[0063] This invention provides a flexible safety control device for electro-hydraulic steering of engineering machinery, as shown in Figure 1, including a first controller 3, an electric control handle 2, an electro-hydraulic steering unit 1, a steering cylinder 5, and an electric control pump 4;

[0064] The electric control handle 2 is connected to the first controller 3 and sends a steering request signal to the first controller 3, causing the first controller 3 to generate a CAN signal or a PWM signal.

[0065] The electro-hydraulic steering unit 1 includes an electro-hydraulic steering module 1.1 and a reversing valve 1.2 connected together. The electro-hydraulic steering module 1.1 is also connected to the first controller 3 via a CAN signal line and a PWM signal line, respectively. The reversing valve 1.2 is also connected to the steering cylinder 5.

[0066] The electrically controlled pump 4 is connected to the first controller 3 and the reversing valve 1.2 respectively;

[0067] The electronic steering module 1.1 responds to the CAN signal or PWM signal sent by the first controller 3, and outputs pilot pressure according to the CAN signal or PWM signal to push the reversing valve 1.2 to switch.

[0068] In the specific implementation process, when the first controller 3 determines that the CAN signal line is faulty, the PWM signal line is used to replace the CAN signal line to realize the vehicle's safe and flexible emergency steering function.

[0069] In one specific embodiment of the present invention, as shown in FIG2, the electronic steering module 1.1 includes: a second controller, a temperature sensor, a current acquisition device, and an electro-proportional valve; the electro-proportional valve is also connected to the reversing valve 1.2;

[0070] The temperature sensor is used to collect the actual oil temperature of the proportional valve in the electronic steering module 1.1 and send it to the second controller. The second controller sends the actual oil temperature of the proportional valve to the first controller 3 via the CAN signal line.

[0071] The current acquisition device is used to acquire the actual current value of the electro-proportional valve in the electronic steering module 1.1 and send it to the second controller. The second controller sends the actual current value of the electro-proportional valve to the first controller 3 through the CAN signal line.

[0072] In the specific implementation process, the actual oil temperature and actual current value of the electro-proportional valve are both used for CAN bus verification.

[0073] In one specific embodiment of the present invention, as shown in FIG1, the electro-hydraulic steering flexible safety control device for engineering machinery further includes a displacement sensor, which is connected to the first controller 3 and the second controller respectively. As shown in FIG3, the first controller 3 includes a CAN bus verification module and a bus displacement module; the CAN bus verification module is connected to the second controller.

[0074] When the CAN bus verification module verifies the signal sent by the second controller via the CAN bus and indicates that the CAN signal line is in normal condition, the bus displacement module calculates the target displacement value of the directional valve spool based on the steering request signal (this calculation process is existing technology and will not be elaborated in detail in this invention), and sends the target displacement value of the directional valve spool to the second controller in the form of a CAN signal via the CAN signal line. The second controller, based on the received target displacement value of the directional valve spool, compares the actual displacement value of the directional valve spool collected by the displacement sensor with the target displacement value of the directional valve spool, calculates the displacement error value, performs PID adjustment based on the displacement error value, outputs a compensated current value, and uses the compensated current value to control the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, thereby pushing the directional valve to switch directions and completing the closed-loop control of the directional valve spool displacement of directional valve 1.2. In specific implementation, when the CAN bus verification module verifies the signal sent by the second controller through the CAN bus, it can specifically include: if the actual oil temperature signal of the electro-proportional valve is lower than the preset value and the actual current value of the electro-proportional valve is within the set current range, it indicates that the CAN signal line is in normal condition and there is no fault; otherwise, it is considered that the CAN signal line is in fault condition.

[0075] In one specific embodiment of the present invention, as shown in FIG4, the first controller 3 further includes an emergency state analysis module and a steering valve control module;

[0076] When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a fault state, the emergency state analysis module activates the PWM signal and sends the PWM signal to the steering valve control module. The steering valve control module calculates the target displacement value of the directional valve core based on the steering request signal (this calculation process is existing technology and will not be described in detail in this invention), calculates the position error with the actual displacement value of the directional valve core, performs PID control based on the displacement error value, calculates the target current of the directional valve, and then calculates the target duty cycle required by the PWM signal based on the actual current value of the directional valve (this calculation process is existing technology and will not be described in detail in this invention). The PWM signal is then sent to the electro-proportional valve in the electronic steering module 1.1, controlling the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, pushing the directional valve to switch, and completing the closed-loop control of the directional valve core displacement based on the actual displacement value of the directional valve core collected by the displacement sensor. As can be seen, in this embodiment of the invention, by installing a displacement sensor and using a steering control module, when the CAN signal line fails, the target duty cycle of the PWM signal is accurately calculated based on the valve core position information of the directional valve, and the vehicle steering is controlled, so as to achieve seamless connection of flow when the CAN signal and PWM signal alternate, and realize the flexibility and stability of vehicle steering.

[0077] Furthermore, when the displacement sensor malfunctions, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. The steering valve control module outputs a corresponding PWM signal (i.e., target current signal) according to the preset steering request signal and the target duty cycle required by the PWM signal, and controls the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, thereby pushing the directional valve 1.2 core to switch directions.

[0078] In one specific embodiment of the present invention, the electric control handle 2 outputs a steering request signal to the first controller 3. Based on the steering request signal, the first controller 3 calculates a corresponding pump displacement adjustment signal and performs real-time control on the electric pump 4 according to the pump displacement adjustment signal to complete the displacement adjustment. In the specific implementation process, a preset mapping relationship exists between the steering request signal and the pump displacement adjustment signal, which is pre-loaded into the first controller 3.

[0079] In one specific embodiment of the present invention, the electric control handle 2 is a dual-bus handle, which is connected to the first controller 3 through an independent first CAN bus and a second CAN bus. When one of the buses fails, the other bus sends a steering control signal to the first controller 3 one cycle later than the bus that failed, so as to ensure the continuity of the CAN bus signal and improve the safety and reliability of the entire device.

[0080] As shown in Figure 2, the working principle of the electro-hydraulic steering flexible safety control device for engineering machinery according to this embodiment of the invention is as follows:

[0081] When the electric control handle 2 sends a first CAN bus control signal (i.e., handle signal or steering request signal), the first CAN bus control signal is transmitted to the first controller 3. The CAN bus verification module in the first controller 3 performs a check code (CRC code) bus verification based on the signal sent by the second controller. During the bus verification, the output signals of the oil temperature sensor and the current acquisition unit are verified. When the CAN bus verification module determines that the CAN signal line is normal, it enters the bus displacement module. The bus displacement module calculates the target displacement value of the directional valve core (i.e., target displacement signal) based on the steering request signal and sends the target displacement value of the directional valve core to the electric steering module 1.1 in the second controller in the form of a CAN signal. The controller calculates the displacement error value based on the received target displacement value of the directional valve core and compares it with the actual displacement value of the directional valve core collected by the displacement sensor. It then performs PID control based on the displacement error value and outputs a compensated current value. This compensated current value is used to control the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, which drives the directional valve 1.2 to switch directions. Simultaneously, the steering request signal is calculated by the first controller 3 to generate a corresponding pump displacement adjustment signal. Based on this signal, the electronic pump 4 is controlled in real time to adjust its displacement. When the directional valve 1.2 switches directions, the pressurized oil in the electronic pump 4 enters the steering cylinder 6, completing the vehicle steering and achieving closed-loop control of the vehicle steering, as shown in Figure 5.

[0082] When the electric control handle 2 sends out the first CAN bus control signal (i.e., handle signal or steering request signal), the first CAN bus control signal is transmitted to the first controller 3. The first controller 3 performs a CAN bus verification module to check the bus using a CRC code. During the bus verification, the output signals of the oil temperature sensor and current acquisition unit are also checked. When the CAN bus verification module determines that the CAN signal line is faulty, it enters the emergency state analysis module to perform emergency state analysis. The emergency state analysis module activates the PWM signal and sends it to the steering valve control module. Based on the steering request signal, the steering valve control module calculates the target displacement value of the directional valve core and calculates the position error between this value and the actual displacement value of the directional valve core sent by the displacement sensor. PID control is then performed based on the displacement error value. The target current of the directional control valve is calculated, and then the target duty cycle required for the PWM signal is calculated based on the actual current value of the directional control valve. The PWM signal (i.e., the target current signal) is sent to the electro-proportional valve in the electronic steering module 1.1 through the PWM signal line. The electro-proportional valve in the electronic steering module 1.1 is controlled to output pilot pressure, which pushes the directional control valve 1.2 to switch. After the directional control valve 1.2 switches, the pressurized oil in the electronic pump 4 enters the steering cylinder 6 to complete the vehicle steering. The directional control valve core displacement is closed-loop control based on the actual displacement value of the directional control valve core collected by the displacement sensor. When the CAN signal line between the electronic steering module 1.1 and the first controller 3 fails, the PWM signal line quickly takes over the control signal according to the vehicle steering information to realize the vehicle's safe and flexible emergency steering function. See Figure 5 for details.

[0083] When the first CAN bus control signal of the electric control handle 2 fails, the second CAN bus sends a control signal to the first controller 3 one cycle later than the first CAN bus, ensuring the continuity of the CAN bus signal.

[0084] Example 2

[0085] This invention provides a flexible safety control method for electro-hydraulic steering in engineering machinery, comprising the following steps:

[0086] (1) Use the electric control handle 2 to send a steering request signal to the first controller 3, so that the first controller 3 generates a CAN signal or a PWM signal;

[0087] (2) The first controller 3 adjusts the displacement of the electronically controlled pump 4 based on the steering request signal;

[0088] (3) Using the electro-hydraulic steering unit 1, the electro-hydraulic steering module 1.1 receives the CAN bus signal sent by the first controller 3 through the CAN signal line or the PWM signal sent through the PWM signal line, and outputs pilot pressure according to the CAN signal or PWM signal to push the reversing valve 1.2 connected to the electro-hydraulic pump 4 in the electro-hydraulic steering unit 1 to reverse, thereby making the steering cylinder 5 connected to the reversing valve 1.2 run.

[0089] In one specific embodiment of the present invention, the electronic steering module 1.1 includes: a second controller, a temperature sensor, a current acquisition device, and an electro-proportional valve; the electro-proportional valve is also connected to the reversing valve 1.2;

[0090] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0091] The actual oil temperature of the proportional valve in the electronic steering module 1.1 is collected by a temperature sensor and sent to the second controller. The second controller then sends the actual oil temperature of the proportional valve to the first controller 3 via a CAN signal line.

[0092] The actual current value of the electro-proportional valve in the electronic steering module 1.1 is collected by a current acquisition device and sent to the second controller. The second controller then sends the actual current value of the electro-proportional valve to the first controller 3 via the CAN signal line.

[0093] In one specific embodiment of the present invention, the first controller 3 includes a CAN bus verification module and a bus offset module; the CAN bus verification module is connected to the second controller.

[0094] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0095] The actual displacement value of the directional valve core is collected by a displacement sensor and sent to the first controller 3 and the second controller.

[0096] When the CAN bus verification module verifies the signal sent by the second controller via the CAN bus and indicates that the CAN signal line is in normal condition, the bus displacement module calculates the target displacement value of the directional valve spool based on the steering request signal (this calculation process is existing technology and will not be elaborated in detail in this invention), and sends the target displacement value of the directional valve spool to the second controller in the form of a CAN signal via the CAN signal line. The second controller, based on the received target displacement value of the directional valve spool, compares the actual displacement value of the directional valve spool collected by the displacement sensor with the target displacement value of the directional valve spool, calculates the displacement error value, performs PID adjustment based on the displacement error value, outputs a compensated current value, and uses the compensated current value to control the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, thereby pushing the directional valve to switch directions and completing the closed-loop control of the directional valve spool displacement of directional valve 1.2. In specific implementation, when the CAN bus verification module verifies the signal sent by the second controller through the CAN bus, it can specifically include: if the actual oil temperature signal of the electro-proportional valve is lower than the preset value and the actual current value of the electro-proportional valve is within the set current range, it indicates that the CAN signal line is in normal condition and there is no fault; otherwise, it is considered that the CAN signal line is in fault condition.

[0097] In one specific embodiment of the present invention, the first controller 3 further includes an emergency status analysis module and a steering valve control module;

[0098] The electro-hydraulic steering flexible safety control method for engineering machinery also includes:

[0099] When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a fault state, the emergency state analysis module activates the PWM signal and sends the PWM signal to the steering valve control module. The steering valve control module calculates the target displacement value of the directional valve core based on the steering request signal (this calculation process is existing technology and will not be described in detail in this invention), calculates the position error with the actual displacement value of the directional valve core, performs PID control based on the displacement error value, calculates the target current of the directional valve, and then calculates the target duty cycle required by the PWM signal based on the actual current value of the directional valve (this calculation process is existing technology and will not be described in detail in this invention). The PWM signal is then sent to the electro-proportional valve in the electronic steering module 1.1, controlling the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, pushing the directional valve to switch, and completing the closed-loop control of the directional valve core displacement based on the actual displacement value of the directional valve core collected by the displacement sensor. As can be seen, in this embodiment of the invention, by installing a displacement sensor and using a steering control module, when the CAN signal line fails, the target duty cycle of the PWM signal is accurately calculated based on the valve core position information of the directional valve, and the vehicle steering is controlled, so as to achieve seamless connection of flow when the CAN signal and PWM signal alternate, and realize the flexibility and stability of vehicle steering.

[0100] In one specific embodiment of the present invention, the electro-hydraulic steering flexible safety control method for engineering machinery further includes:

[0101] When the displacement sensor malfunctions, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module. The steering valve control module outputs the corresponding PWM signal (i.e., the target current signal) according to the preset steering request signal and the target duty cycle required by the PWM signal. This controls the electro-proportional valve in the electronic steering module 1.1 to output pilot pressure, which pushes the directional valve 1.2 core to switch directions.

[0102] In one specific embodiment of the present invention, the first controller 3 adjusts the displacement of the electronically controlled pump 4 based on the steering request signal, specifically including:

[0103] The electric control handle 2 outputs a steering request signal to the first controller 3. Based on the steering request signal, the first controller 3 calculates the corresponding pump displacement adjustment signal and performs real-time control on the electric pump 4 according to the pump displacement adjustment signal to complete the displacement adjustment. In specific implementation, there is a preset mapping relationship between the steering request signal and the pump displacement adjustment signal, which is pre-loaded into the first controller 3.

[0104] In one specific embodiment of the present invention, the electric control handle 2 is a dual-bus handle, which is connected to the first controller 3 via an independent first CAN bus and a second CAN bus. The electro-hydraulic steering flexible safety control method for engineering machinery further includes:

[0105] When one of the buses fails, the other bus sends a steering control signal to the first controller 3 one cycle later than the failed bus, ensuring the continuity of the CAN bus signal and improving the safety and stability of the device.

[0106] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0107] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An electro-hydraulic steering flexible safety control device for a working machine, characterized in that, The first controller, an electric control handle, an electro-hydraulic steering unit, a steering cylinder and an electric control pump are included. The electric control handle is connected with the first controller and sends a steering request signal to the first controller, so that the first controller generates a CAN signal or a PWM signal. The electro-hydraulic steering unit includes an electric control steering module and a reversing valve connected with each other, the electric control steering module is further connected with the first controller through a CAN signal line and a PWM signal line respectively, and the reversing valve is further connected with the steering cylinder in communication. The electric control pump is connected with the first controller and the reversing valve respectively. The electric control steering module responds to the CAN signal or the PWM signal sent by the first controller and outputs a pilot pressure according to the CAN signal or the PWM signal to push the reversing valve to reverse.

2. An electro-hydraulic steering flexible safety control device for a working machine according to claim 1, characterized in that, The electric control steering module includes a second controller, a temperature sensor, a current collector and an electric proportional valve, and the electric proportional valve is further connected with the reversing valve. The temperature sensor is used to collect an actual oil temperature of the electric proportional valve in the electric control steering module and send the actual oil temperature to the second controller, and the second controller sends the actual oil temperature of the electric proportional valve to the first controller through a CAN signal line. The current collector is used to collect an actual current value of the electric proportional valve in the electric control steering module and send the actual current value to the second controller, and the second controller sends the actual current value of the electric proportional valve to the first controller through a CAN signal line.

3. An electro-hydraulic steering flexible safety control device for a working machine according to claim 2, characterized in that: The engineering machinery electro-hydraulic steering flexible safety control device further includes a displacement sensor connected with the first controller and the second controller respectively, the first controller includes a CAN bus verification module and a bus displacement module. The CAN bus verification module is connected with the second controller. When the CAN bus verification module passes the CAN bus verification based on the signal sent by the second controller, it indicates that the CAN signal line is in a normal state, then the bus displacement module calculates a target displacement value of a spool of the reversing valve based on the steering request signal, and sends the target displacement value of the spool of the reversing valve to the second controller in the form of a CAN signal, the second controller compares an actual displacement value of the spool of the reversing valve collected by the displacement sensor with the target displacement value of the spool of the reversing valve based on the received target displacement value of the spool of the reversing valve, calculates a displacement error value, performs PID adjustment according to the displacement error value, outputs a compensated current value, controls the electric proportional valve in the electric control steering module to output a pilot pressure by using the compensated current value, pushes the reversing valve to reverse, and completes displacement closed-loop control of the spool of the reversing valve.

4. An electro-hydraulic steering flexible safety control device for a working machine according to claim 3, characterized in that: The first controller further includes an emergency state analysis module and a steering valve control module. When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, it indicates that the CAN signal line is in a fault state, then the emergency state analysis module activates a PWM signal and sends the PWM signal to the steering valve control module. The steering valve control module calculates a target displacement value of a steering valve spool based on the steering request signal, and performs position error calculation with an actual displacement value of the steering valve spool sent by a displacement sensor, performs PID control according to the displacement error value, calculates a target current of the steering valve, and then calculates a target duty ratio required by a PWM signal based on an actual current value of the steering valve, and sends the PWM signal to an electric proportional valve in the electric control steering module to control the electric proportional valve in the electric control steering module to output a pilot pressure to push the steering valve to steer, and complete displacement closed-loop control of the steering valve spool according to the actual displacement value of the steering valve spool collected by the displacement sensor.

5. An electro-hydraulic steering flexible safety control device for a working machine according to claim 4, characterized in that: When the displacement sensor fails, the emergency state analysis module activates the PWM signal and sends it to the steering valve control module, which outputs a corresponding PWM signal according to a preset correspondence between the steering request signal and the target duty ratio required by the PWM signal, controls the electric proportional valve in the electric control steering module to output a pilot pressure to push the steering valve spool to steer.

6. An electro-hydraulic steering flexible safety control device for construction machines according to claim 1, characterized in that: The electric control handle outputs a steering request signal to the first controller, which calculates a corresponding pump displacement adjustment signal based on the steering request signal and controls the electric control pump in real time according to the pump displacement adjustment signal to complete displacement adjustment.

7. An electro-hydraulic steering flexible safety control device for construction machinery according to claim 1, characterized in that: The electric control handle is a double-bus handle connected to the first controller through independent first and second CAN buses, so that when one of the buses fails, the other bus sends a steering control signal to the first controller one cycle later than the failed bus to ensure continuous CAN bus signals.

8. An electro-hydraulic steering flexible safety control method of a working machine, characterized by, It comprises: sending a steering request signal from an electric control handle to a first controller to make the first controller generate a CAN signal or a PWM signal; adjusting the displacement of an electric control pump based on the steering request signal by the first controller; receiving a CAN bus signal sent by the first controller through a CAN signal line or a PWM signal sent through a PWM signal line by an electric control steering module in an electro-hydraulic steering unit, and outputting a pilot pressure according to the CAN signal or the PWM signal to push a steering valve connected to the electric control pump to steer, thereby making a steering cylinder connected to the steering valve operate.

9. An electro-hydraulic steering flexible safety control method of a working machine according to claim 8, characterized by: The electric control steering module comprises a second controller, a temperature sensor, a current collector, and an electric proportional valve, and the electric proportional valve is also connected to the steering valve. The flexible safety control method for the engineering machinery electro-hydraulic steering further comprises: collecting the actual oil temperature of the electric proportional valve in the electric control steering module by a temperature sensor and sending it to the second controller, and sending the actual oil temperature of the electric proportional valve to the first controller by the second controller through a CAN signal line; collecting the actual current value of the electric proportional valve in the electric control steering module by a current collector and sending it to the second controller, and sending the actual current value of the electric proportional valve to the first controller by the second controller through a CAN signal line.

10. A method of electro-hydraulic steering flexible safety control of a working machine according to claim 9, characterized in that: The first controller comprises a CAN bus verification module and a bus displacement module; The CAN bus verification module is connected to the second controller; The engineering machinery electro-hydraulic steering flexible safety control method further comprises: The actual displacement value of the reversing valve spool is collected by the displacement sensor and sent to the first controller and the second controller; When the CAN bus verification module passes the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a normal state, the target displacement value of the reversing valve spool is calculated by the bus displacement module based on the steering request signal, and the target displacement value of the reversing valve spool is sent to the second controller in the form of a CAN signal. The second controller compares the target displacement value of the reversing valve spool with the actual displacement value of the reversing valve spool collected by the displacement sensor based on the received target displacement value of the reversing valve spool, calculates the displacement error value, performs PID adjustment according to the displacement error value, outputs the compensated current value, controls the pilot pressure output by the electric proportional valve in the electric control steering module using the compensated current value, drives the reversing valve to reverse, and completes the displacement closed-loop control of the reversing valve spool.

11. An electro-hydraulic steering flexible safety control method of a working machine according to claim 10, characterized by: The first controller further comprises an emergency state analysis module and a steering valve control module; The engineering machinery electro-hydraulic steering flexible safety control method further comprises: When the CAN bus verification module fails to pass the CAN bus verification based on the signal sent by the second controller, indicating that the CAN signal line is in a fault state, the PWM signal is activated by the emergency state analysis module and sent to the steering valve control module. The steering valve control module calculates the target displacement value of the reversing valve spool based on the steering request signal, and calculates the position error with the actual displacement value of the reversing valve spool sent by the displacement sensor. PID control is performed according to the displacement error value, the target current of the reversing valve is calculated, and then the target duty cycle required by the PWM signal is calculated based on the actual current value of the reversing valve. The PWM signal is sent to the electric proportional valve in the electric control steering module to control the pilot pressure output by the electric proportional valve in the electric control steering module, drive the reversing valve to reverse, and complete the displacement closed-loop control of the reversing valve spool according to the actual displacement value of the reversing valve spool collected by the displacement sensor. The engineering machinery electro-hydraulic steering flexible safety control method further comprises:

12. An electro-hydraulic steering flexible safety control method of a working machine according to claim 11, characterized by: When the displacement sensor fails, the PWM signal is activated by the emergency state analysis module and sent to the steering valve control module. The steering valve control module outputs the corresponding PWM signal according to the preset correspondence between the steering request signal and the target duty cycle required by the PWM signal, controls the pilot pressure output by the electric proportional valve in the electric control steering module, and drives the reversing valve spool to reverse. The first controller based on the steering request signal to adjust the displacement of the electric control pump, specifically:

13. An electro-hydraulic steering flexible safety control method of a construction machine according to claim 8, characterized by: The electric control handle outputs the steering request signal to the first controller. The first controller calculates the corresponding pump displacement adjustment signal based on the steering request signal, and controls the electric control pump in real time according to the pump displacement adjustment signal to complete displacement adjustment. ​ 14. An electro-hydraulic steering flexible safety control method of a construction machine according to claim 8, characterized by: The electric control handle is a double-bus handle, which is connected with the first controller through independent first and second CAN buses, and the flexible safety control method of the construction machinery electro-hydraulic steering further comprises: When one of the buses fails, the other bus is used to send a steering control signal to the first controller one cycle later than the failed bus, ensuring the continuity of the CAN bus signal.

Images