A method and system for graded control of steering faults in wheeled cranes

Abstract

This invention discloses a graded control method and system for steering faults in wheeled cranes. The mechanical steering axle and electro-hydraulic steering axle of the wheeled crane are each equipped with angle sensors. For cranes with a single mechanical steering axle, angle sensors are installed on both sides. For cranes with two or more mechanical axles, angle sensors are installed on the same side of each mechanical axle, and the angle sensors of the electro-hydraulic steering axle are installed on the same side as the mechanical axle. A single angle sensor failure in a mechanical axle is classified as a Level 1 fault. A single angle sensor failure in an electro-hydraulic steering axle, or a single angle sensor failure in both mechanical and electro-hydraulic steering axles, is classified as a Level 2 fault. Two or more angle sensor failures in either the mechanical or electro-hydraulic steering axle are classified as a Level 3 fault. This invention categorizes faults into Level 1, Level 2, and Level 3 based on the number and location of the angle sensor failures, and performs graded processing for each level of fault.

Description

Technical Field

[0001] This invention relates to the field of wheeled crane steering, and in particular to a method and system for graded control of steering faults in wheeled cranes. Background Technology

[0002] Wheeled cranes require both long-distance, high-speed travel and tight-space maneuvering, resulting in varying turning radius requirements depending on the application. Therefore, most wheeled cranes possess all-wheel steering capabilities and offer multiple steering modes to meet the turning needs of different application scenarios. Different steering modes correspond to different steering centers and varying steering angles of the axles and tires, thus exhibiting different turning radii.

[0003] To achieve precise control of the wheel angles of each axle, angle sensors are installed on both the mechanical steering axle 1 and the electro-hydraulic steering axle. In the selected steering mode, when the steering wheel controls the rotation of the mechanical steering axle 1 tires, the controller reads the tire angle of the mechanical steering axle and, based on the functional relationship between the tire angles of each electro-hydraulic steering axle and the mechanical steering axle angle in the current mode, calculates the target rotation angle for each electro-hydraulic steering axle tire in real time. The angle sensors on each electro-hydraulic steering axle continuously collect the current tire rotation angle. Based on the difference between the target rotation angle and the current rotation angle, the controller controls the energization of the corresponding lock-up solenoid valve and steering proportioning solenoid valve in real time, controlling the hydraulic circuit to hydraulically drive the corresponding lock-up cylinder and steering cylinder, thus pushing the electro-hydraulic steering axle tires to the target rotation angle.

[0004] When a certain angle sensor malfunctions, it cannot accurately obtain the tire steering angle of that axle, thus making it impossible to control the steering angle. For safety and to ensure the vehicle can still be driven, the controller will control the corresponding solenoid valve to pull the tires of each electro-hydraulic steering axle back to the neutral position through the locking cylinder to lock them, so that the tires of each electro-hydraulic steering axle no longer participate in steering, and mechanical steering is controlled only by the steering wheel. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method and system for graded control of steering faults of wheeled cranes, which addresses the shortcomings of the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A graded control method for steering faults in a wheeled crane is disclosed, wherein angle sensors are installed on both the mechanical steering axle and the electro-hydraulic steering axle of the wheeled crane. Specifically, for a crane with a single mechanical steering axle, angle sensors are installed on both sides; for a crane with two or more mechanical axles, angle sensors are installed on the same side of each mechanical axle, and the angle sensors of the electro-hydraulic steering axle are installed on the same side as the mechanical axle. A fault in a single angle sensor of a mechanical axle is classified as a Level 1 fault; a fault in a single angle sensor of the electro-hydraulic steering axle, or a fault in both a single angle sensor of the mechanical axle and a single angle sensor of the electro-hydraulic steering axle, is classified as a Level 2 fault; a fault in two or more angle sensors of either the mechanical axle or the electro-hydraulic steering axle is classified as a Level 3 fault.

[0008] As a further preferred embodiment of the present invention, for a crane with a single mechanical steering axle, when the steering controller identifies a first-level fault and the angle sensor on the same side as the electro-hydraulic steering axle is faulty, the angle signal acquisition of mechanical axle 1 will automatically switch to the angle sensor on the other side, and the angle of mechanical axle 1 will be calculated based on the trapezoidal relationship between the left and right wheels of mechanical axle 1, thereby calculating the target steering angle of the electro-hydraulic steering axle tires; if the angle sensor on a different side from the electro-hydraulic steering axle is faulty, the controller will only send fault information for display prompts.

[0009] As a further preferred embodiment of the present invention, for cranes with two or more mechanical axles, when the steering controller identifies a first-level fault and a sensor fault in mechanical axle 1, the controller will calculate the real-time angle of mechanical axle 1 based on the mechanical connection relationship between mechanical axle 1 and mechanical axle 2, and the target turning angle of the electro-hydraulic steering axle will still be calculated based on the angle of mechanical axle 1; if the angle sensor of mechanical axle 2 is faulty, the controller will only send fault information for display prompts.

[0010] As a further preferred embodiment of the present invention, if the secondary fault is a fault of the angle sensor of a single electro-hydraulic steering axle, in this state, the current steering mode enters the fault mode, and the electro-hydraulic steering axle enters the neutral position lock state by default. At this time, emergency steering control can be realized through authorization via the vehicle display.

[0011] As a further preferred embodiment of the present invention, if the secondary fault is a single angle sensor fault of the mechanical axle plus a single angle sensor fault of the electro-hydraulic steering axle, then in this state, the handling method for the single angle sensor fault of the mechanical axle is the same as the handling method for the primary fault, and the handling method for the single angle sensor fault of the electro-hydraulic steering axle is the same as the handling method for the single angle sensor fault of the electro-hydraulic steering axle in the secondary fault. The processed mechanical axle angle can be used to calculate the target steering angle of each electro-hydraulic steering axle. The processed electro-hydraulic steering axle angle, as a feedback angle, is used to realize tire steering of the faulty axle and the uncontrolled axle according to a preset control strategy.

[0012] As a further preferred embodiment of the present invention, in the third-level fault state, if both angle sensors of the mechanical axle are faulty, the target tire steering angle of the electro-hydraulic steering axle cannot be obtained; if two or more electro-hydraulic steering axles are faulty, the theoretical actual steering angle cannot be calculated through the steering relationship between adjacent steering wheels or the calculated steering angle is severely distorted. Therefore, in the third-level fault state, the electro-hydraulic steering axle is locked in the center position, and the mechanical axle steering is controlled only by the steering wheel.

[0013] As a further preferred embodiment of the present invention, in the first-level fault, only the display provides an icon reminder and a text reminder, and all axles can participate in steering normally; in the second-level fault, the display provides an icon flashing reminder and a text reminder, and the electro-hydraulic steering axle defaults to the neutral lock-up mode, but with the authorization of the display, the electro-hydraulic steering axle can be allowed to perform emergency steering according to the set strategy, while limiting the highest gear of the transmission, thereby limiting the vehicle speed to not exceed the set value and ensuring driving safety; in the third-level fault, the display provides corresponding reminders including icon flashing reminders, text reminders and audible alarms, and the electro-hydraulic steering axle returns to the neutral lock-up mode.

[0014] A graded control system for steering faults of a wheeled crane includes a mechanical steering assembly, a body controller, a display, an input device, a steering controller, an angle sensor, a steering valve, a hydraulic cylinder, and a hydraulic oil tank. The angle sensor is installed on the mechanical axle and the electro-hydraulic steering axle of the crane and is connected to the steering controller. The body controller is connected to the steering controller, the display, and the input device. The display is installed in the crane's cab.

[0015] The present invention has the following beneficial effects:

[0016] 1. From a probabilistic perspective, the probability of two or more angle sensors malfunctioning simultaneously is extremely low. The solution provided by this invention ensures that the tires of the electro-hydraulic steering axle can still steer even when the angle sensors malfunction to level three or below, avoiding the situation where the electro-hydraulic steering axle locks in the center position and increases the turning radius in the event of a malfunction.

[0017] 2. In the event of a failure of the secondary angle sensor, emergency steering can be permitted via a display authorization method to achieve emergency steering safety management.

[0018] 3. During emergency steering, the maximum vehicle speed is limited by actively restricting the gearbox gears, which ensures both normal engine torque output and vehicle driving safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the steering system of the present invention;

[0020] Figure 2 This is a flowchart of the steering fault classification control of the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0022] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0023] 1. Definitions of abbreviations and key terms:

[0024] Crane: refers to a multi-action lifting machine that vertically lifts and horizontally moves heavy objects within a certain range; also known as a crane.

[0025] Emergency steering control: The steering of the tires can still be controlled even in the event of a malfunction.

[0026] Mechanical steering: refers to controlling the steering of the wheels through the action of the steering wheel, steering gear and mechanical linkage.

[0027] Electro-hydraulic steering: refers to the use of electrical signals to control corresponding solenoid valves to open the hydraulic circuit, which in turn drives the corresponding locking cylinder and steering cylinder to steer the wheels.

[0028] 2. System composition of the present invention:

[0029] The system of this invention comprises: a mechanical steering assembly, including a steering wheel, a steering pump, etc.; a body controller; a display; an input device; a steering controller; an angle sensor; steering valves and cylinders (steering lock-up valve, steering proportioning valve, steering lock-up cylinder, and steering cylinder); and a hydraulic oil tank. A schematic diagram of the steering system is attached. Figure 1 As shown.

[0030] 3. Overall Plan:

[0031] This invention provides a method and system for graded control of steering faults in wheeled cranes. The mechanical steering axle and electro-hydraulic steering axle of the wheeled crane are each equipped with angle sensors. For cranes with a single mechanical steering axle, angle sensors are installed on both the left and right sides. For cranes with two or more mechanical axles, angle sensors are installed on the same side of mechanical axle 1 and mechanical axle 2, and the angle sensor of the electro-hydraulic steering axle is installed on the same side as the mechanical axle. (See attached diagram.) Figure 1When a certain electro-hydraulic steering axle angle sensor fails, in order to continue steering, angle sensors can be installed on the tires on both sides of the electro-hydraulic steering axle respectively; in the case of multiple mechanical axles, the installation position of the angle sensors is not limited to mechanical axle 1 and mechanical axle 2.

[0032] 4. Normal Mode:

[0033] With all angle sensors functioning normally, after the engine starts, when the controller receives the steering signal from the mechanical axle 1, it determines the current steering mode and whether the electro-hydraulic steering axle is allowed to participate in steering. If not, the electro-hydraulic steering axle tires return to the center position and lock; if allowed, the controller unlocks the electro-hydraulic steering axle and calculates the target steering angle for each electro-hydraulic steering axle tire based on the angle relationship between each electro-hydraulic steering axle and the mechanical axle 1. Simultaneously, it calculates the difference between the angle collected by the angle sensors on each electro-hydraulic steering axle and the target angle. Based on the magnitude of the difference and according to the control algorithm, the controller controls the current of the corresponding steering proportioning valve to control the steering of the corresponding steering axle tires.

[0034] 5. Failure Modes:

[0035] This invention classifies the failures of angle sensors, a fundamental component of steering control. A single angle sensor failure in the mechanical axle is classified as a Level 1 failure; a single angle sensor failure in the electro-hydraulic steering axle, or a combination of a single angle sensor failure in the mechanical axle and a single angle sensor failure in the electro-hydraulic steering axle, is classified as a Level 2 failure; and failures in two or more angle sensors in either the mechanical axle or the electro-hydraulic steering axle are classified as a Level 3 failure.

[0036] 5.1 Primary angle sensor failure:

[0037] For cranes with a single mechanical steering axle, when the steering controller detects a Level 1 fault and the angle sensor on the same side as the electro-hydraulic steering axle is faulty, the angle signal acquisition for mechanical axle 1 will automatically switch to the angle sensor on the other side. Based on the trapezoidal relationship between the left and right wheels of mechanical axle 1, the angle of mechanical axle 1 will be calculated, and the target steering angle of the electro-hydraulic steering axle tires will be determined accordingly. If the angle sensor on a different side from the electro-hydraulic steering axle is faulty, the controller will only send fault information for display purposes.

[0038] For cranes with two or more mechanical axles, when the steering controller detects a Level 1 fault and a sensor failure in mechanical axle 1, the controller will calculate the real-time angle of mechanical axle 1 based on the mechanical connection between mechanical axles 1 and 2, using the angle of mechanical axle 2. The target steering angle of the electro-hydraulic steering axle will still be calculated based on the angle of mechanical axle 1. If the angle sensor of mechanical axle 2 fails, the controller will only send fault information for display notification.

[0039] A failure of the primary angle sensor does not affect the normal steering function of the crane, so the fault is only displayed on the screen, preferably in the form of an icon and text.

[0040] 5.2 Secondary angle sensor failure:

[0041] 5.2.1 Failure of a single angle sensor on the electro-hydraulic steering axle:

[0042] In this state, the current steering mode enters fault mode, and the electro-hydraulic steering axle is locked in the neutral position by default. At this time, emergency steering control can be achieved through authorization via the onboard display. Specifically, after receiving the emergency steering authorization information from the display, the steering controller, based on the driver's selected target steering mode and according to the preset functional relationship between the faulty axle and the adjacent electro-hydraulic steering axles, calculates the current steering angle information of the faulty axle in real time, using it as the steering feedback angle for the faulty axle. According to the preset control strategy, the tire steering of both the faulty and non-faulty axles is controlled.

[0043] 5.2.2 Failure of a single angle sensor on the mechanical axle plus failure of a single angle sensor on the electro-hydraulic steering axle:

[0044] In this state, the handling method for a single angle sensor failure in the mechanical axle is the same as that for angle sensor failures in section 5.1, and the handling method for a single angle sensor failure in the electro-hydraulic steering axle is the same as that for a second-level angle sensor failure in section 5.2.1. The processed mechanical axle angle can be used to calculate the target steering angle of each electro-hydraulic steering axle; the processed electro-hydraulic steering axle angle, as a feedback angle, is used to realize tire steering of the faulty axle and the uncontrolled axle according to the preset control strategy.

[0045] Since steering control under a level 2 fault is an emergency control measure, to ensure driving safety, the vehicle's maximum speed will be limited by restricting the highest gear in the transmission. The speed limiting function during emergency steering can also be achieved by limiting the engine's maximum speed in a specific gear.

[0046] 5.3 Level 3 Angle Sensor Failure:

[0047] In this state, if both angle sensors of the mechanical steering axle malfunction, the target tire steering angle of the electro-hydraulic steering axle cannot be obtained. If two or more electro-hydraulic steering axles malfunction, the theoretical actual steering angle cannot be calculated based on the steering relationship between adjacent steering points, or the calculated steering angle will be severely distorted. Therefore, under a level three fault condition, the electro-hydraulic steering axle is locked in the neutral position, and the mechanical steering axle is controlled solely by the steering wheel. In this state, the maximum vehicle speed is not limited.

[0048] 6. Control Process

[0049] As attached Figure 2 As shown, the steering controller performs real-time diagnostics on the angle sensor. When a fault occurs, the controller classifies the fault according to a set strategy and adopts corresponding steering control strategies based on the fault level: Level 1 fault: only the display provides a warning, preferably with an icon and text warning, and all axles can participate in steering normally; Level 2 fault: the display provides a warning, preferably with a flashing icon and text warning, and the electro-hydraulic steering axle enters the neutral lock-up mode by default. However, with authorization from the display, the electro-hydraulic steering axle can be allowed to perform emergency steering according to a set strategy, while limiting the highest gear of the transmission to limit the vehicle speed to a set value and ensure driving safety; Level 3 fault: the display provides a corresponding warning, preferably with a flashing icon, text warning, and audible alarm, and the electro-hydraulic steering axle returns to the neutral lock-up mode and no longer participates in steering.

[0050] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for steering fault staging control of a wheel crane, characterized by: The mechanical steering bridge and the electro-hydraulic steering bridge of the wheel crane are respectively provided with an angle sensor; for the crane with a single mechanical steering bridge, the angle sensors are respectively arranged on both sides of the mechanical steering bridge; for the crane with two or more mechanical steering bridges, the angle sensors are respectively arranged on the same side of the mechanical steering bridge, and the angle sensor of the electro-hydraulic steering bridge is arranged on the same side of the mechanical steering bridge; The single angle sensor fault of the mechanical steering bridge is a first-level fault; the single angle sensor fault of the electro-hydraulic steering bridge or the single angle sensor fault of the mechanical steering bridge plus the single angle sensor fault of the electro-hydraulic steering bridge is a second-level fault; the two or more angle sensor faults of the mechanical steering bridge or the electro-hydraulic steering bridge is a third-level fault, In the first-level fault, for the crane with a single mechanical steering bridge, when the steering controller identifies that it is a first-level fault and the angle sensor fault is on the same side of the electro-hydraulic steering bridge, the angle signal acquisition of the mechanical steering bridge will be automatically switched to the angle sensor on the other side, and the angle of the mechanical steering bridge is calculated according to the trapezoidal relationship between the left and right wheels of the mechanical steering bridge, so as to calculate the target angle of the tire of the electro-hydraulic steering bridge; if the angle sensor fault is on the different side of the electro-hydraulic steering bridge, the controller only sends the fault information for display prompt; In the first-level fault, for the crane with two or more mechanical steering bridges, when the steering controller identifies that it is a first-level fault and the angle sensor fault is of the mechanical steering bridge, the controller will calculate the real-time angle of the mechanical steering bridge and the target angle of the electro-hydraulic steering bridge according to the mechanical connection relationship between the mechanical steering bridge and the mechanical steering bridge, and the target angle of the electro-hydraulic steering bridge is still calculated according to the angle of the mechanical steering bridge; if the angle sensor fault is of the mechanical steering bridge, the controller only sends the fault information for display prompt; In the second-level fault, if the angle sensor fault is of the single electro-hydraulic steering bridge, in this state, the current steering mode enters the fault mode, the electro-hydraulic steering bridge enters the neutral locking state by default, and the steering emergency control can be realized through the authorization of the vehicle-mounted display; In the second-level fault, if the angle sensor fault is of the single electro-hydraulic steering bridge plus the single angle sensor fault of the mechanical steering bridge, the processing method for the single angle sensor fault of the mechanical steering bridge is the same as that of the first-level fault, and the processing method for the single angle sensor fault of the electro-hydraulic steering bridge is the same as that of the second-level fault of the single electro-hydraulic steering bridge; The processed angle of the mechanical steering bridge can be used to calculate the target angle of each electro-hydraulic steering bridge, and the processed angle of the electro-hydraulic steering bridge is used as the feedback angle to realize the tire steering of the fault bridge and the non-control bridge according to the preset control strategy; In the third-level fault, if the two angle sensors of the mechanical steering bridge are both faulty, the target angle of the tire of the electro-hydraulic steering bridge cannot be obtained; if two or more angle sensors of the electro-hydraulic steering bridge are faulty, the theoretical actual angle cannot be calculated or the calculated angle is distorted seriously through the steering relationship between the adjacent steering bridges, so the electro-hydraulic steering bridge is controlled to be in the neutral locking state in the third-level fault, and the mechanical steering bridge is controlled to steer only through the steering wheel. Primary fault, only display prompts including icon prompts and text prompts, each bridge can normally participate in steering; Secondary fault, display prompts including icon flashing and text prompts, and the electro-hydraulic steering bridge defaults to enter the neutral locking mode, but through the display authorization, the electro-hydraulic steering bridge can be allowed to perform emergency steering according to the set strategy, while limiting the highest gear of the gearbox, thereby limiting the vehicle speed not to exceed the set value, ensuring the driving safety; Third fault, the display has corresponding prompts including icon flashing prompts, text prompts and sound alarms, and the electro-hydraulic steering bridge returns to the neutral locking.

2. A control system suitable for use in a slewing crane steering fault staging control method as claimed in claim 1, characterised in that: The mechanical steering assembly, the vehicle body controller, the display, the input device, the steering controller, the angle sensor, the steering valve, the oil cylinder and the hydraulic oil tank are included; the angle sensor is arranged on the mechanical steering bridge and the electro-hydraulic steering bridge of the crane, the angle sensor is connected with the steering controller, the vehicle body controller is connected with the steering controller, the display and the input device respectively, and the display is arranged in the cab of the crane.

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