A method and system for controlling multi-source load overload operation of a ladder rack of a ladder fire engine

Abstract

The application discloses a ladder rack multi-source load overload operation control method and system of a cloud ladder fire engine, adopts a strain sensor to detect strain values generated by multi-source loads such as arm frame self weight, platform load, wind load, acceleration inertia load, water cannon counterforce, bridge counterforce and the like in real time, and then calculates real-time bending moments of the ladder rack from the strain values. When the real-time bending moment of the ladder rack is less than the maximum bending moment, the ladder rack can continue to increase the amplitude even if overloaded, otherwise, the ladder rack will stop the action. When the real-time bending moment of the ladder rack approaches the maximum bending moment, the ladder rack is proportionally decelerated until the action stops. The application can realize overload control within the safe operation range of the cloud ladder fire engine, and effectively improves the rescue efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery, and in particular to a method and system for controlling multi-source load overload operations of a ladder frame of an aerial ladder fire truck. Background Art

[0002] Aerial ladder trucks, also known as aerial ladder trucks, are a key component of aerial fire trucks. They are primarily used for rescue operations, while also providing jet firefighting capabilities. The ladder frame of an aerial ladder truck typically features a telescopic straight-arm structure, with the base hinged to the vehicle's turntable and the front end connected to the work platform. Through various movements, including turntable rotation, ladder boom adjustment, and ladder telescoping, rescue operations can be performed within varying ranges and operating envelopes.

[0003] During rescue operations, ladder fire trucks must use outrigger support to evenly distribute force, ensuring stability within varying operating ranges. Currently, domestic ladder fire trucks only allow for onboard operations after fixed outrigger span support. The ladder operates within a fixed operating range curve, and the platform's load capacity is fixed. This makes it impossible to control operations when the platform is overloaded, preventing increased working space and impacting rescue efficiency.

[0004] The existing domestic ladder fire truck dismounting includes two working conditions: full extension of the horizontal legs or full extension of one side and half extension of the other side. After the horizontal extension of the dismounting legs and the vertical support force are completed, the available stability torque can be calculated based on the horizontal length of the dismounting legs and the force conditions of each vertical leg. The safe operation curve for getting on the vehicle can be determined based on the stability torque. Because the dismounting mode is fixed, the getting on vehicle operation mode is also limited. When switching the getting on vehicle operation mode, the ladder can only work within the absolute safe operation range curve and when the platform is not overloaded. At present, the multi-source load sources on the ladder are limited to the ladder weight and platform load. When the platform load is overloaded, the movement will be immediately restricted even if it is within the set safe operation range curve. The existing technology has the following problems: (1) In the existing technology, the safe operation curve of the whole vehicle is obtained by theoretical calculation, and the ladder bending moment and the whole vehicle overturning moment generated by different loads on the ladder cannot be monitored in real time; (2) In the existing technology, the platform load is strictly limited to the safe load capacity range. When the platform is overloaded, even if it is far less than the safe operation curve range, the ladder movement will be restricted. Summary of the Invention

[0005] The present invention aims to provide a method and system for controlling the overload of a ladder frame on an aerial ladder fire truck. The method employs strain sensors to detect in real time the strain generated by multiple load sources, including the boom's deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force, and bridge reaction force. The system then calculates the real-time bending moment of the ladder frame from these strain values. When the real-time bending moment is less than the maximum bending moment under that amplitude, the ladder frame maintains sufficient stability and strength margins. Even if the ladder frame is overloaded, it can still perform amplitude-increasing actions such as extension and retraction, amplitude adjustment, and left and right rotation. The present invention effectively controls overload actions by detecting strain sensor values ​​in real time.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck, comprising:

[0008] Determine the current ladder frame operating range based on the current ladder frame angle, turntable angle, and ladder frame length information, and match the current safe operation curve;

[0009] Based on the matched current safe operation curve, according to the one-to-one correspondence between the maximum vehicle tipping moment and the vehicle safe operation curve, the maximum vehicle tipping moment under the current ladder frame operating range is obtained;

[0010] According to the mapping relationship between the maximum bending moment of the ladder frame and the maximum overturning moment of the vehicle, the maximum bending moment of the ladder frame under the current ladder frame operating range is calculated;

[0011] Obtain and correct the strain values ​​of the ladder frame under the current ladder frame operating range due to multiple loads, and calculate the real-time ladder frame bending moment; the multiple loads include: ladder frame deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force, and bridge reaction force;

[0012] Based on the real-time ladder frame bending moment and the maximum value of the ladder frame bending moment under the current ladder frame operation range, multi-source load overload operation control is performed in the following manner:

[0013] when When , the ladder frame is controlled to continue to move; otherwise, when When the ladder is controlled to stop, is the real-time ladder bending moment, is the maximum bending moment of the ladder frame under the current ladder frame operating range, is the preset safety factor.

[0014] Furthermore, when When the ladder frame is controlled to continue to move, including:

[0015] when and >0.9 When the ladder frame is controlled to enter the proportional deceleration mode, the specific steps are:

[0016] The control hydraulic valve input signal is multiplied by a deceleration coefficient s;

[0017] when ≤0.9 When the ladder is controlled, it will continue to move at the original speed.

[0018] Furthermore, the mapping relationship between the maximum value of the ladder frame bending moment and the maximum overturning moment of the vehicle is determined as follows:

[0019] Build a ladder rack multi-source load simulation model, and simulate the vehicle overturning moment under different ladder rack operating ranges by adjusting the multi-source load input. and ladder bending moment The different ladder operation ranges refer to the different ladder angles and ladder lengths during ladder operation.

[0020] According to the simulation results, the vehicle overturning moment under different ladder frame operating ranges is obtained. and ladder bending moment The relationship becomes a nonlinear increasing relationship. When the overturning moment When the maximum is reached, the ladder frame bending moment It also reaches a maximum value, and the maximum value of the ladder frame bending moment is determined based on the maximum value of the overturning moment;

[0021] According to the maximum tipping moment and maximum bending moment of the ladder frame under different ladder frame operating amplitudes obtained by simulation, a mapping relationship curve between the maximum bending moment of the ladder frame and the maximum tipping moment of the vehicle is fitted.

[0022] Furthermore, the step of obtaining and correcting the strain values ​​of the multi-source loads acting on the ladder frame under the current ladder frame operating range and calculating the real-time ladder frame bending moment includes:

[0023] By installing strain sensors on the ladder frame, the strain values ​​of the ladder frame under the current ladder frame operating range caused by multiple source loads are obtained;

[0024] Correct the strain values ​​as follows:

[0025] ;

[0026] Let the strain correction term 0.1 times the measured strain value ,but:

[0027] ;

[0028] in, is the corrected strain value, is the measured strain value, is the strain correction term,

[0029] Based on the functional relationship between the ladder frame bending moment and the strain value, the ladder frame bending moment corresponding to the corrected strain value is calculated.

[0030] Furthermore, the safety factor k is between 1.1 and 1.3.

[0031] Furthermore, the deceleration coefficient s is set to:

[0032] .

[0033] The present invention also provides a multi-source load overload operation control system for a ladder fire truck ladder frame, which is used to implement the aforementioned multi-source load overload operation control method for a ladder fire truck ladder frame. The control system includes a ladder fire truck dismount, a slewing mechanism, a ladder frame, a platform, and a load, and further includes:

[0034] Displacement sensor, used to detect the overall length of the ladder frame;

[0035] Angle sensor, used to detect the angle of the ladder frame;

[0036] A strain sensor is used to detect the strain value of the ladder frame caused by multiple source loads;

[0037] The displacement sensor, angle sensor and strain sensor are all connected to the controller;

[0038] The controller is used to collect ladder frame length, ladder frame angle and ladder frame strain value, determine the current ladder frame operating range according to the current ladder frame angle and ladder frame length information, and match the current safe operation curve; based on the matched current safe operation curve, according to the one-to-one correspondence between the maximum overturning moment of the whole vehicle and the safety operation curve of the whole vehicle, obtain the maximum value of the ladder frame bending moment under the current ladder frame operating range according to the mapping relationship between the maximum value of the ladder frame bending moment and the maximum value of the vehicle overturning moment; obtain the strain value of the multi-source load acting on the ladder frame under the current ladder frame operating range and correct it, and calculate the real-time ladder frame bending moment; the multi-source load includes: ladder frame deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force and bridging reaction force; based on the real-time ladder frame bending moment and the maximum value of the ladder frame bending moment under the current ladder frame operating range, perform multi-source load overload operation control in the following manner:

[0039] when When , the ladder frame is controlled to continue to move; otherwise, when When the ladder is controlled to stop, is the real-time ladder bending moment, is the maximum bending moment of the ladder frame under the current ladder frame operating range, is the preset safety factor.

[0040] Furthermore, the controller is specifically configured to:

[0041] when and >0.9 When the ladder frame is controlled to enter the proportional deceleration mode, the specific steps are:

[0042] The control hydraulic valve input signal is multiplied by a deceleration coefficient s;

[0043] when ≤0.9 When the ladder is controlled, it will continue to move at the original speed.

[0044] Furthermore, the angle sensor is installed at the connection point between the ladder frame and the turntable.

[0045] Furthermore, the strain sensor is installed on the side of the ladder frame 1m in front of the hinge point between the luffing cylinder and the ladder frame.

[0046] Furthermore, the displacement sensor is installed at the tail of the ladder frame.

[0047] The beneficial effects of the present invention are:

[0048] (1) The present invention provides a control method for overloading the ladder frame of a fire truck. The method detects the strain value through a strain sensor to calculate the bending moment of the ladder frame, and can provide real-time feedback on the stress of the ladder frame. This method can better cope with complex and changing on-site environments and improve operational stability.

[0049] (2) The present invention detects and calculates the real-time bending moment of the ladder frame through strain sensor detection, and compares it with the maximum overturning moment under the current amplitude, thereby achieving overload control within the safe operating range of the ladder fire truck and effectively improving the rescue efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A control system architecture for overloaded operation of a ladder frame of a ladder fire truck provided by the present invention;

[0051] Figure 2 This is a schematic diagram showing the calculation principle of the overturning moment of the ladder frame in the present invention;

[0052] Figure 3 This is a flow chart of the control method for overloading the ladder frame of an aerial ladder fire truck provided by the present invention. DETAILED DESCRIPTION

[0053] The present invention will be further described below. The following examples are only used to more clearly illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention.

[0054] The present invention provides a multi-source load overload operation control system for the ladder frame of a fire truck, such as Figure 1 As shown, it includes a ladder fire truck dismount 1, a slewing mechanism 2, a ladder frame 7, a platform and a load 9, and also includes:

[0055] The displacement sensor 4 is used to detect the overall length l of the ladder frame and is installed at the tail of the ladder frame;

[0056] Angle sensor 5, used to detect the ladder frame angle α, installed at the connection point between the ladder frame and the turntable;

[0057] Strain sensor 6, used to detect the strain value of the ladder frame caused by multiple source loads , installed on the side of the ladder frame 1m in front of the hinge point between the luffing cylinder and the ladder frame;

[0058] The displacement sensor 4, angle sensor 5 and strain sensor 6 are all connected to the controller.

[0059] Controller 3 is used to collect the ladder frame length, ladder frame angle and ladder frame strain value, calculate the current ladder frame bending moment, and output a control signal to control the opening of the hydraulic valve and the movement of the ladder frame based on the relationship between the current ladder frame bending moment and the maximum ladder frame bending moment; the controller is installed in the turntable control box.

[0060] Figure 8 is the safe operation curve of the whole vehicle.

[0061] Based on the above control system, the present invention provides a control method for overloading the ladder frame of an aerial ladder fire truck, including the following contents:

[0062] (1) Calculate the mapping relationship between the maximum value of the ladder frame bending moment and the maximum value of the vehicle overturning moment as follows:

[0063] The multi-source loads such as ladder frame deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force and bridge reaction force can be equivalent to the total external force F at a certain point of the ladder frame. t The magnitude and direction of the resultant external force change with the change of the ladder angle, ladder length, and multi-source load. t The moment calculation of the vehicle's rotation center can obtain the real-time tipping moment of the vehicle. The ladder bending moment can be obtained by decomposing the moment in different directions And the torque compensation term ΔM. Its calculation model is as follows Figure 2 As shown,

[0064] Point O in the figure is the center of rotation of the vehicle, which is fixed. Point P is the resultant external force F t The center point, point P, changes in real time with the changes in the ladder frame angle, ladder frame length and various loads. Point S is the vertical intersection of the rotation center point O and the ladder frame, and changes in real time with the changes in the ladder frame.

[0065] According to the moment calculation principle, the overturning moment calculation formula can be obtained:

[0066] ;

[0067] ;

[0068] ;

[0069] in, is the vehicle tipping moment, Resulting external force The moment arm about the rotation center O is: 、 The external forces are The lever arm after decomposition in the vertical direction and the horizontal direction of the ladder frame.

[0070] Decomposing the vehicle tipping moment in the vertical and horizontal directions of the ladder frame yields:

[0071] ;

[0072] ;

[0073] Finally, the relationship between the vehicle tipping moment and the ladder frame bending moment is obtained:

[0074] ;

[0075] In the above formula, is the ladder frame bending moment, which can be measured and calculated by the strain sensor; It is a moment compensation item, which is related to the ladder frame’s deadweight, ladder frame length, wind load, platform load and acceleration inertia load.

[0076] Due to the net external force F t The calculation is complex. Based on the above theoretical calculation principle, the present invention uses simulation to simulate the vehicle tipping moment and ladder frame bending moment under different operating ranges. Specifically,

[0077] Build a ladder rack multi-source load simulation model. Under different ladder rack operating ranges, by adjusting the multi-source load and other inputs, simulate and solve the vehicle overturning moment under different ladder rack operating ranges. and ladder bending moment .

[0078] It should be noted that, in the present invention, different ladder operating ranges refer to different ladder angles and ladder lengths during ladder operation.

[0079] Analyze the vehicle overturning moment under different ladder frame operating ranges based on simulation results and ladder bending moment Relationship, the tipping moment in the plane of tipping With the bending moment at the selected position of the ladder stand In a nonlinear increasing relationship, when the tipping moment Reaches the maximum, the bending moment of the ladder stand Also reaches the maximum value, and the maximum bending moment of the ladder stand Is mapped to the maximum tipping moment of the whole vehicle According to the simulation results.

[0080] The maximum tipping moment of the whole vehicle Is the maximum tipping moment Corresponds to the safe operation curve of the whole vehicle, and the maximum tipping moment under different postures of the ladder stand can be inversely calculated according to the safe operation amplitude under the posture , the maximum bending moment of the ladder stand And the maximum tipping moment of the whole vehicle The mapping relationship curve can obtain the maximum bending moment of the ladder stand under the posture, that is, the maximum bending moment of the ladder stand And the maximum tipping moment of the whole vehicle also has a one-to-one mapping relationship.

[0081] (2) Calculate the real-time bending moment of the ladder stand, as follows:

[0082] The bending moment of the ladder stand and the strain value of the ladder stand have a linear function relationship, which can be calculated by the formula:

[0083] ;

[0084] The ideal strain value of the ladder stand, in actual use, due to the influence of factors such as the length of the ladder stand , the angle of the ladder stand , the self weight m of the ladder stand, the position change of the gravity center of the ladder stand, processing error, assembly error and the like, a strain correction term Is added to the strain value measured by the strain sensor , to obtain the corrected strain value, and the bending moment of the ladder stand is calculated,

[0085] In the present application, the strain correction term Is 0.1 times the measured strain value , that is:

[0086] ;

[0087] The final calculation relationship between the bending moment of the ladder stand And the strain value measured by the strain sensor Is:

[0088] . ​

[0089] (3) Based on the above calculation and mapping curve fitting results, overload control is performed as follows. The control process is shown in Figure 3 ,

[0090] When the controller receives the ladder frame amplitude change, ladder frame extension or turntable rotation handle signal, it determines the current ladder frame operating range based on the current ladder frame angle, turntable angle, ladder frame length and other parameter information, and automatically matches the current safe operation curve range;

[0091] According to the maximum tipping moment One-to-one correspondence with the vehicle's safe operating curve and the current safe operating curve to calculate the maximum tipping moment of the current amplitude ;

[0092] According to the maximum bending moment of the ladder frame Maximum overturning moment of the vehicle The mapping relationship is used to obtain the maximum bending moment of the ladder frame under the current amplitude. ;

[0093] When the handle sends an action signal, the strain value detected by the strain sensor is obtained and corrected to calculate the real-time ladder frame bending moment. ;

[0094] Control is performed as follows:

[0095] when Even if it is overloaded, the ladder frame can be extended, the ladder frame can be changed, the turntable can be rotated, and other amplitude-increasing actions can be completed; otherwise, when When the ladder is controlled to stop immediately, is the preset safety factor;

[0096] Furthermore, when and >0.9 When , the ladder frame enters the proportional deceleration mode, and the hydraulic valve input signal is multiplied by a deceleration coefficient s to continue the action. The value range of s is limited to 0~1. The s value is calculated as follows:

[0097] ;

[0098] Otherwise, when ≤0.9 The ladder frame will continue to move at the original speed.

[0099] The cycle ends and the next cycle begins.

[0100] It should be noted that the safety factor k is set between 1.1 and 1.3 according to actual conditions.

[0101] Explanation of terms:

[0102] Multi-source loads: loads on the ladder frame such as ladder frame deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force, bridge reaction force, etc.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck, characterized in that: include: Determine the current ladder frame operating range based on the current ladder frame angle, turntable angle, and ladder frame length information, and match the current safe operation curve; Based on the matched current safe operation curve, according to the one-to-one correspondence between the maximum vehicle tipping moment and the vehicle safe operation curve, the maximum vehicle tipping moment under the current ladder frame operating range is obtained; According to the mapping relationship between the maximum bending moment of the ladder frame and the maximum overturning moment of the vehicle, the maximum bending moment of the ladder frame under the current ladder frame operating range is calculated; The mapping relationship between the maximum value of the ladder frame bending moment and the maximum overturning moment of the vehicle is determined as follows: Build a ladder rack multi-source load simulation model, and simulate the vehicle overturning moment under different ladder rack operating ranges by adjusting the multi-source load input. and ladder bending moment The different ladder operation ranges refer to the different ladder angles and ladder lengths during ladder operation. According to the simulation results, the vehicle overturning moment under different ladder frame operating ranges is obtained. and ladder bending moment The relationship becomes a nonlinear increasing relationship. When the overturning moment When the maximum is reached, the ladder frame bending moment It also reaches a maximum value, and the maximum value of the ladder frame bending moment is determined based on the maximum value of the overturning moment; Based on the maximum tipping moment and maximum bending moment of the ladder frame under different ladder frame operating ranges obtained by simulation, a mapping relationship curve between the maximum bending moment of the ladder frame and the maximum tipping moment of the vehicle is fitted; Obtain and correct the strain values ​​of the ladder frame under the current ladder frame operating range due to multiple loads, and calculate the real-time ladder frame bending moment; the multiple loads include: ladder frame deadweight, platform load, wind load, acceleration inertia load, water monitor reaction force, and bridge reaction force; Based on the real-time ladder frame bending moment and the maximum value of the ladder frame bending moment under the current ladder frame operation range, multi-source load overload operation control is performed in the following manner: when When , the ladder frame is controlled to continue to move; otherwise, when When the ladder is controlled to stop, is the real-time ladder bending moment, is the maximum bending moment of the ladder frame under the current ladder frame operating range, is the preset safety factor.

2. A method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck according to claim 1, characterized in that: When When the ladder frame is controlled to continue to move, including: when and >0.9 When the ladder frame is controlled to enter the proportional deceleration mode, the specific steps are: The control hydraulic valve input signal is multiplied by a deceleration coefficient s; when ≤0.9 When the ladder is controlled, it will continue to move at the original speed.

3. A method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck according to claim 1, characterized in that: Obtaining and correcting the strain values ​​of the ladder frame caused by the multi-source loads under the current ladder frame operating range, and calculating the real-time ladder frame bending moment, including: By installing strain sensors on the ladder frame, the strain values ​​of the ladder frame under the current ladder frame operating range caused by multiple source loads are obtained; Correct the strain values ​​as follows: ； Let the strain correction term 0.1 times the measured strain value ,but: ； in, is the corrected strain value, is the measured strain value, is the strain correction term, Based on the functional relationship between the ladder frame bending moment and the strain value, the ladder frame bending moment corresponding to the corrected strain value is calculated.

4. A method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck according to claim 1, characterized in that: The safety factor k is 1.1-1.

3.

5. A method for controlling multi-source overload operation of a ladder frame of an aerial ladder fire truck according to claim 2, characterized in that: The deceleration coefficient s is set to: 。 6. A control system for multi-source overload operation of a ladder frame of a ladder fire truck, used to implement the multi-source overload operation control method of a ladder frame of a ladder fire truck according to any one of claims 1 to 5, wherein the control system comprises a ladder fire truck dismount, a slewing mechanism, a ladder frame, a platform, and a load, and is characterized in that: Also includes: Displacement sensor, used to detect the overall length of the ladder frame; Angle sensor, used to detect the angle of the ladder frame; A strain sensor is used to detect the strain value of the ladder frame caused by multiple source loads; The displacement sensor, angle sensor and strain sensor are all connected to the controller; The controller is used to collect ladder frame length, ladder frame angle and ladder frame strain value, determine the current ladder frame operating range based on the current ladder frame angle and ladder frame length information, and match the current safe operation curve; based on the matched current safe operation curve, according to the one-to-one correspondence between the maximum vehicle tipping moment and the vehicle safe operation curve, obtain the maximum vehicle tipping moment under the current ladder frame operating range; according to the mapping relationship between the maximum ladder frame bending moment and the maximum vehicle tipping moment, calculate the maximum ladder frame bending moment under the current ladder frame operating range; The strain values ​​of the multi-source loads acting on the ladder frame at the current ladder frame operating range are obtained and corrected, and the real-time ladder frame bending moment is calculated. The multi-source loads include: the ladder frame's own weight, platform load, wind load, acceleration inertia load, water monitor reaction force, and bridge reaction force. Based on the real-time ladder frame bending moment and the maximum value of the ladder frame bending moment at the current ladder frame operating range, the multi-source load overload operation control is performed as follows: when When , the ladder frame is controlled to continue to move; otherwise, when When the ladder is controlled to stop, is the real-time ladder bending moment, is the maximum bending moment of the ladder frame under the current ladder frame operating range, is the preset safety factor.

7. A multi-source load overload operation control system for a ladder frame of an aerial ladder fire truck according to claim 6, characterized in that: The controller is specifically used to: when and >0.9 When the ladder frame is controlled to enter the proportional deceleration mode, the specific steps are: The control hydraulic valve input signal is multiplied by a deceleration coefficient s; when ≤0.9 When the ladder is controlled, it will continue to move at the original speed.

8. A multi-source load overload operation control system for a ladder frame of an aerial ladder fire truck according to claim 6, characterized in that: The angle sensor is installed at the connection point between the ladder frame and the turntable.

9. A multi-source load overload operation control system for a ladder frame of an aerial ladder fire truck according to claim 6, characterized in that: The strain sensor is installed on the side of the ladder frame 1m in front of the hinge point between the luffing cylinder and the ladder frame.

10. A multi-source load overload operation control system for a ladder frame of an aerial ladder fire truck according to claim 6, characterized in that: The displacement sensor is installed at the tail of the ladder frame.

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