A bidirectional loading calibration device and calibration method for a steering tie rod in tension and compression

Abstract

The present invention discloses a bidirectional loading calibration device and method for a steering tie rod, including a loading screw, a connecting frame, a connecting plate, a load sensor support, a strain gauge, a data acquisition device, and a computer; the loading screw is rotatably installed on a first loading screw support and a second loading screw support; one end of the loading screw is provided with a loading operation part, the other end of the loading screw is connected to the first end of the connecting frame, and the second end of the connecting frame is used for connecting the first end of the steering tie rod. The connecting plate is installed on the load sensor support through the load sensor and is used for connecting the second end of the rotating tie rod; the strain gauge is used to be attached to the steering tie rod, and its signal wire is connected to the data acquisition device. The signal wire of the load sensor is connected to the data acquisition device, and the data acquisition device is connected to the computer. This calibration device has a simple structure, is easy to operate, has a low cost, and can obtain more accurate calibration data.

Description

Technical Field

[0001] The present invention relates to the technical field of steering tie rod calibration, and particularly to a bidirectional tension and compression loading calibration device for a steering tie rod. The present invention also relates to a calibration method using the calibration device for calibration. Background Art

[0002] The steering tie rod of an automobile consists of a left steering tie rod and a right steering tie rod. When turning left, the left steering tie rod bears pressure and the right steering tie rod bears tension, and vice versa.

[0003] In order to obtain the tensile and compressive forces borne by the steering tie rod, the common practice is to paste strain gauges at appropriate positions on the steering tie rod, and then calculate the force value of the tie rod according to the collected strain value. The calibration coefficient is used in the calculation process. The calibration coefficient is the correlation coefficient between strain and force, and the calibration coefficient is obtained through the calibration process. During the calibration process, tensile strain is obtained by applying tensile force to the tie rod, and compressive strain corresponding to the pressure can also be obtained, so as to obtain the calibration coefficients of tensile force and compressive force respectively. Obviously, calibration requires a calibration device that can fix the steering tie rod and transmit tensile and compressive forces, as well as a recording method for force and strain values and a method for obtaining the calibration coefficient.

[0004] The existing calibration device and calibration method are as follows: after loading to a force value each time, the tester writes down the force value displayed on the main control machine of the actuator, and then reads and records the strain value at this force value from the computer connected to the data acquisition device. In this way, three to five groups of force values and their corresponding strain values are obtained, and then the calibration coefficient is obtained by the graphical method.

[0005] The above-mentioned calibration device and calibration method have the following disadvantages:

[0006] The first disadvantage is that the loading equipment is expensive and complex to operate. The purchase cost of the hydraulic servo loading system composed of an actuator, a controller, a main control machine, a pump station, hydraulic oil, hoses, and a cooling system (such as a cooling tower, a chiller, etc.) for controlling the temperature of the hydraulic oil in the pump station is more than 5 million yuan. The software and hardware structures of this equipment are relatively complex. Adjusting PID parameters, closed-loop control of force, and setting limit protection all require strong knowledge and experience in electronics, machinery, hydraulics, control, etc. Therefore, only trained personnel can operate and use the equipment safely and correctly.

[0007] The second drawback is that there are relatively large errors in the recording of test data. The test force and strain data are recorded by the experimenter, who has to record the values of force and strain separately. This recording method leads to the asynchronous recording of force values and strain values. This asynchrony causes problems with the time sequence of recording force values and strain values, and the non-correspondence between the two will generate errors. Especially when the force value is affected by factors such as hydraulic system fluctuations, the errors in this regard will become significantly larger. In addition, the experimenter separately reads and records the force and strain values, which will introduce human errors and sometimes even cause errors in reading or recording. The efficiency of this loading and recording method is also relatively low.

[0008] The third drawback is that there are relatively large errors in data processing. In the process of obtaining the calibration coefficient by the graphical method, there is a large degree of arbitrariness in drawing the connecting lines, especially when the data is scattered and the amount of data is small, relatively large errors will be generated. Summary of the Invention

[0009] The object of the present invention is to provide a bidirectional tension and compression loading calibration device for a steering tie rod to solve the above technical problems.

[0010] Another object of the present invention is to provide a calibration method using the bidirectional tension and compression loading calibration device for a steering tie rod.

[0011] To achieve the above object, the present invention provides a bidirectional tension and compression loading calibration device for a steering tie rod, including a loading screw, a connecting frame, a connecting plate, a load sensor support, a strain gauge, a data acquisition device, and a computer; the loading screw is rotatably installed on a first loading screw support and a second loading screw support, the first loading screw support is provided with a first threaded hole threadedly engaged with the loading screw, and the second loading screw support is provided with a second threaded hole threadedly engaged with the loading screw; one end of the loading screw is provided with a loading operation part, the other end of the loading screw is connected to the first end of the connecting frame, and the second end of the connecting frame is used for connecting the first end of the steering tie rod; the connecting plate is installed on the load sensor support through the load sensor, and the connecting plate is used for connecting the second end of the rotating tie rod; the strain gauge is used for attaching to the steering tie rod, and its signal wire is connected to the data acquisition device, the signal wire of the load sensor is connected to the data acquisition device, and the data acquisition device is connected to the computer.

[0012] Optionally, the center line of the connecting frame is collinear with the axis of the loading screw.

[0013] Optionally, the second end of the connecting frame is connected to the threaded end of the steering tie rod, and the tightening torque of their threaded connection is the same as that of the actual vehicle.

[0014] Optionally, the connecting plate is in an "L" shape. Its horizontal plate is used to connect the ball joint of the steering tie rod, and its vertical plate is connected to the load sensor support through a load sensor. The tightening torque between the ball joint and the horizontal plate should be the same as that of the actual vehicle.

[0015] Optionally, the vertical plate of the load sensor support is provided with a vertical sliding groove, and the load sensor is slidably mounted in the sliding groove to fix the load sensor when the axis of the steering tie rod is collinear with the center line of the connecting frame.

[0016] Optionally, the loading operation part is a loading handle.

[0017] To achieve the above another object, the present invention provides a method for calibrating the two-way tension and compression of a steering tie rod. It uses the steering tie rod two-way tension and compression calibration device described in any one of the above to perform calibration, including:

[0018] Install the steering tie rod on the steering tie rod two-way tension and compression calibration device;

[0019] Attach the strain gauge to the steering tie rod;

[0020] Start the data acquisition device and the computer, and set the parameters of the strain gauge and the load sensor;

[0021] Perform preloading of tension and pressure;

[0022] Formally load tension and pressure, and synchronously collect tension data, pressure data, and strain data;

[0023] Use the least squares method to perform linear fitting on the collected tension data, pressure data, and strain data to obtain the best calibration coefficient.

[0024] Furthermore,

[0025] The performing of the preloading of tension and pressure includes:

[0026] Apply a tensile preload to each steering tie rod. Before loading, zero the force and strain on the computer, then make the data acquisition device enter the acquisition state. The maximum value of the tensile preload is the maximum value of the calibrated tension. When the applied force is close to the maximum calibrated tension, slow down the loading speed. After reaching the maximum value of the calibrated tension, make the data acquisition device stop collecting, and then unload to the zero-force state;

[0027] Apply a compressive preload to each steering tie rod. Before loading, zero the force and strain on the computer, then make the data acquisition device enter the acquisition state. The maximum value of the compressive preload is the maximum value of the calibrated tension. When the applied force is close to the maximum calibrated pressure, slow down the loading speed. After reaching the maximum value of the calibrated pressure, make the data acquisition device stop collecting, and then unload to the zero-force state.

[0028] Furthermore,

[0029] The formal tensile and compressive loading includes:

[0030] On the computer, zero the force and strain. The data acquisition device starts to acquire data. By rotating the loading screw through the loading operation part, apply tensile force to the steering tie rod, and simultaneously acquire tensile force data and strain data synchronously. The maximum tensile loading value is the maximum calibrated tensile force. When the applied force approaches the maximum calibrated tensile force, slow down the loading speed. After reaching the maximum calibrated tensile force, stop the data acquisition device, and then unload until the force reaches the zero state;

[0031] On the computer, zero the force and strain. The data acquisition device starts to acquire data. By rotating the loading screw through the loading operation part, apply compressive force to the steering tie rod, and simultaneously acquire compressive force data and strain data synchronously. The maximum compressive loading value is the maximum calibrated compressive force. When the applied force approaches the maximum calibrated compressive force, slow down the loading speed. After reaching the maximum calibrated compressive force, stop the data acquisition device, and then unload until the force reaches the zero state.

[0032] Furthermore,

[0033] It also includes, after determining the calibration coefficient, judging the quality of calibration according to whether the value of the linearity R 2 obtained by fitting is close to 1.

[0034] The two-way tensile and compressive loading calibration device for the steering tie rod provided by the present invention applies a load to the steering tie rod through the threaded fit between the loading screw and the loading screw support. There is no need to set up guiding devices such as linear bearings, which is convenient for machining and manufacturing, and can significantly reduce the machining and manufacturing costs. Moreover, the device can be easily operated by manual force for loading, and there is no need for power consumption of at least 60 kW / h like that of actuator loading during use (the power of at least one oil pump is 45 kW / h, and the power of the cooling water pump and the controller is at least 15 kW / h). It also does not require the operator to have strong knowledge and experience in multiple aspects such as electronics, machinery, hydraulics, and control like hydraulic servo equipment.

[0035] The two-way tensile and compressive loading calibration method for the steering tie rod provided by the present invention can synchronously and automatically acquire tensile force data, compressive force data, and strain data, reducing the errors caused by equipment fluctuations and the asynchrony of manual separate recordings. In addition, the calibration coefficient obtained based on a large amount of acquired tensile force data, compressive force data, and strain data further reduces the error of the result compared with the result obtained by manually recording data; and the best calibration coefficient linearly fitted by the least squares method also reduces the error of obtaining the calibration coefficient compared with the graphical method, and the linearity R 2 value obtained by fitting can be used to evaluate the fitting quality. Description of the Drawings

[0036] Figure 1A schematic structural diagram of a device for calibrating a steering rod tension and compression bidirectional loading provided by an embodiment of the present invention;

[0037] Figure 2 A flow chart of a method for calibrating a steering rod's tension-compression bidirectional loading provided by an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the linear fitting results of the pressure calibration of a certain model of steering rod.

[0039] In the picture:

[0040] 1. Loading handle; 2. First loading screw support; 3. Loading screw; 4. Second loading screw support; 5. Connecting frame; 6. Strain gauge; 7. Strain signal line; 8. Computer; 9. Network cable; 10. Data acquisition equipment; 11. Load sensor signal line; 12. Load sensor support; 13. Load sensor; 14. Connecting plate; 15. Steering rod. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0042] In this article, terms such as "upper, lower, inside, outside" are established based on the positional relationships shown in the drawings. Depending on the different drawings, the corresponding positional relationships may also change accordingly. Therefore, they cannot be understood as absolute limitations on the scope of protection; moreover, relational terms such as "first" and "second" are only used to distinguish one component from another with the same name, and do not necessarily require or imply any actual relationship or order between these components.

[0043] Please refer to Figure 1 , Figure 1 This is a structural schematic diagram of a steering rod tension and compression bidirectional loading calibration device provided by an embodiment of the present invention.

[0044] In a specific embodiment, the steering rod tension and compression bidirectional loading calibration device provided by the present invention is mainly composed of a loading screw 3, a connecting frame 5, a connecting plate 14, a load sensor support 12, a strain gauge 6, a data acquisition device 10 and a computer 8.

[0045] The loading screw 3 can be a fine-thread screw to enable more delicate operations. It is rotatably installed on the first loading screw support 2 and the second loading screw support 4. The first loading screw support 2 is provided with a first threaded hole that is threadedly engaged with the loading screw 3, and the second loading screw support 4 is provided with a second threaded hole that is threadedly engaged with the loading screw 3. The double-support structure formed by the first loading screw support 2 and the second loading screw support 4 plays a role in loading, supporting, and guiding during the loading process.

[0046] One end of the loading screw 3 is provided with a loading handle 1. By rotating the loading handle 1, the loading screw 3 can be rotated and move forward or backward while rotating, thereby applying pressure or tension to the steering tie rod 15.

[0047] The connecting frame 5 is generally in a rectangular frame structure. The other end of the loading screw 3 is connected to the first end of the connecting frame 5. Since the loading screw 3 rotates and moves at the same time, a rotatable connecting mechanism is used between the loading screw 3 and the first end of the connecting frame 5. The second end of the connecting frame 5 is used to connect to the first end of the steering tie rod 15, that is, the threaded end of the steering tie rod 15. The tightening torque of their threaded connection is the same as that of the actual vehicle. During calibration, it should be ensured that the center line of the connecting frame 5 is collinear with the axis of the loading screw 3.

[0048] The connecting plate 14 is in an "L" shape. Its horizontal plate is used to connect to the second end of the steering tie rod 15, that is, to connect to the end of the steering tie rod 15 where the ball joint is provided. Its vertical plate is connected to the load sensor support 12 through the load sensor 13. The tightening torque of the ball joint and the horizontal plate should be the same as that of the actual vehicle.

[0049] The vertical plate of the load sensor support 12 is provided with a vertical chute. During installation, the load sensor 13 slides up and down along the chute until the axis of the steering tie rod 15 is basically collinear with the center line of the connecting frame 5, and then the load sensor 13 is fixed.

[0050] The strain gauge 6 is used to be attached to the steering tie rod 15. Its signal wire is connected to the data acquisition device 10. The signal wire of the load sensor 13 is also connected to the data acquisition device 10. The data acquisition device 10 is further connected to the computer 8 through a network cable.

[0051] Please refer to Figure 2 , Figure 2 which is a flowchart of a method for calibrating the two-way tensile and compressive loading of a steering tie rod provided by an embodiment of the present invention.

[0052] In a specific embodiment, the process of the method for calibrating the two-way tensile and compressive loading of the steering tie rod provided by the present invention is as follows:

[0053] Installation: Install the steering tie rod 15 on the two-way tensile and compressive loading calibration device for the steering tie rod, and attach the strain gauge 6 to the steering tie rod 15.

[0054] Parameter setting: Start the data acquisition device 10 and the computer 8. After the communication between the two is completed, set the parameters such as the layer, channel, sampling frequency, excitation voltage, sensitivity coefficient, and range where the strain gauges 6 and load sensors 13 are located in the data acquisition software of the computer 8.

[0055] Preloading: Apply a preload of tension and pressure to the steering tie rod 15 once before the formal loading. The main purpose of preloading is to eliminate influencing factors such as system clearances and reduce test errors. In addition, observe whether the working state of the acquisition system composed of strain gauges, data acquisition devices, and computers is normal.

[0056] When the loading handle 1 rotates counterclockwise, the load applied is tension, and when it rotates clockwise, the load applied is pressure. First, perform the tension preloading. Before loading, zero the force and strain on the computer 8, then make the data acquisition device 10 enter the acquisition state. When loading, rotate the loading handle 1 counterclockwise as slowly, steadily, and uniformly as possible to apply a tension preload to the steering tie rod 15. The maximum value of the tension preload is the maximum value of the calibrated tension. Observe the magnitude of the applied load while loading. When the applied load is close to the maximum calibrated tension, slow down the loading speed. Since the loading screw 3 is a fine-thread screw, it is relatively easy to accurately control the magnitude of the applied load. After reaching the maximum value of the calibrated tension, make the data acquisition device 10 stop collecting data, and then rotate the loading handle 1 clockwise to unload until the force is zero. Refer to the tension preloading method to complete the pressure preloading, loading, and unloading processes.

[0057] Formal loading and synchronous acquisition of tension data, pressure data, and strain data: First, perform the tension loading (pressure loading can also be carried out first). Zero the force and strain on the computer 8, and the data acquisition device 10 starts to collect data. Apply tension to the steering tie rod 15 up to the maximum calibrated tension in accordance with the above tension preloading method while synchronously collecting tension data and strain data. Then, the data acquisition device 10 stops collecting data, and rotate the loading handle 1 counterclockwise to unload until the force is zero; zero the force and strain, and refer to the tension loading method to complete the pressure loading, acquisition, and unloading.

[0058] Obtain the calibration coefficient: Use the least squares method to perform linear fitting on a large amount of collected tension data, pressure data, and strain data to obtain the best calibration coefficient. The quality of the calibration can also be judged based on the linearity R 2 value obtained from the fitting. The closer this value is to 1, the better the calibration effect. An example of the linear fitting result of pressure calibration is as shown in Figure 3As shown in the figure, the pressure calibration coefficient in the figure is -199.59 N / microstrain, where microstrain is the unit of strain called microstrain. The meaning of this calibration coefficient is that every 199.59 N of pressure can cause the steering tie rod 15 to generate 1 compressive microstrain. If the maximum compressive strain collected after the steering tie rod is installed on the actual vehicle is -10 microstrain (microstrain), then the corresponding pressure is 1995.9 N [(-199.59)*(-10) = 1995.9]. Moreover, the linearity R 2 The value of is 1, indicating that the calibration result is relatively ideal.

[0059] The above embodiments are only the preferred solutions of the present invention, and are not specifically limited thereto. On this basis, targeted adjustments can be made according to actual needs to obtain different implementation manners. For example, add a machine platform, and uniformly install the components of the above calibration device on the machine platform. When calibrating, operate on the machine platform, and so on. Since there are many possible implementation methods, they will not be exemplified one by one here.

[0060] The beneficial effects that the present invention can achieve are as follows:

[0061] 1) Extremely low cost: First, the manufacturing cost is low. The structure of the entire set of calibration device is simple. The double-screw support structure also eliminates the need for guiding devices such as linear bearings, which is convenient for processing and manufacturing. The processing and manufacturing cost can be controlled at about 1000 yuan, which is extremely low compared with the purchase cost of more than 5 million yuan for the hydraulic servo actuator system. Second, it can be easily operated by relying only on manpower, and there is no need for power consumption of at least 60 kW / h for actuator loading during use (the power of at least one oil pump is 45 kW / h, and the power of the cooling water pump and controller is at least 15 kW / h), and the usage cost is basically zero.

[0062] 2) Easy to operate: It can be easily seen from the above loading process that this solution is simple to operate, completely different from hydraulic servo equipment, which requires operators to have strong knowledge and experience in multiple aspects such as electronics, machinery, hydraulics, and control, and only personnel who have received special training can use the equipment safely and correctly.

[0063] 3) Lower error: Synchronously and automatically collecting force and strain reduces the errors caused by equipment fluctuations and the asynchrony of manual separate recordings. In addition, the calibration coefficient obtained based on a large number of collected force and strain values further reduces the error of the result compared with the result obtained from three to five groups of data recorded manually; the best calibration coefficient linearly fitted by the least squares method also reduces the error of obtaining the calibration coefficient compared with the graphical method, and the linearity R2 value fitted can also be used to evaluate the fitting quality.

[0064] The above has introduced in detail the steering tie rod tensile and compressive bidirectional loading calibration device and method provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A bidirectional loading calibration device for a steering tie rod under tension and compression, characterized in that It includes a loading screw, a connecting frame, a connecting plate, a load sensor support, a strain gauge, a data acquisition device and a computer; the loading screw is rotatably installed on a first loading screw support and a second loading screw support, the first loading screw support is provided with a first threaded hole threadedly engaged with the loading screw, and the second loading screw support is provided with a second threaded hole threadedly engaged with the loading screw; one end of the loading screw is provided with a loading operation part, the other end of the loading screw is connected to the first end of the connecting frame, and the second end of the connecting frame is used for connecting the first end of a steering tie rod; the connecting plate is installed on the load sensor support through a load sensor and is used for connecting the second end of a rotating tie rod; the strain gauge is used for being attached to the steering tie rod, and its signal wire is connected to the data acquisition device, the signal wire of the load sensor is connected to the data acquisition device, and the data acquisition device is connected to the computer; the center line of the connecting frame is collinear with the axis of the loading screw; the second end of the connecting frame is connected to the threaded end of the steering tie rod, and the tightening torque of their threaded connection is the same as that of the actual vehicle; the connecting plate is in an "L" shape, its horizontal plate is used for connecting the ball joint of the steering tie rod, and its vertical plate is connected to the load sensor support through a load sensor, and the tightening torque of the ball joint and the horizontal plate should be the same as that of the actual vehicle; the vertical plate of the load sensor support is provided with a vertical sliding groove, and the load sensor can be slidably installed in the sliding groove to fix the load sensor when the axis of the steering tie rod is collinear with the center line of the connecting frame; the loading operation part is a loading handle.

2. A method for bidirectional tension and compression calibration of a steering tie rod, which is calibrated by using the bidirectional tension and compression calibration device for a steering tie rod described in claim 1 above, includes: Install the steering tie rod on the bidirectional tension and compression calibration device for a steering tie rod; Attach the strain gauge to the steering tie rod; Start the data acquisition device and the computer, and set the parameters of the strain gauge and the load sensor; Perform preloading of tension and pressure; Formally load tension and pressure, and synchronously collect tension data, pressure data and strain data; Perform linear fitting on the collected tension data, pressure data and strain data by using the least squares method to obtain the best calibration coefficient.

3. According to the method for bidirectional tension and compression calibration of a steering tie rod described in claim 2, characterized in that The performing of the preloading of tension and pressure includes: Apply a tension preload to each steering tie rod. Before loading, zero the force and strain on the computer, then make the data acquisition device enter the acquisition state. The maximum value of the tension preload is the maximum value of the calibrated tension. When the applied force is close to the maximum calibrated tension, slow down the loading speed. After reaching the maximum value of the calibrated tension, make the data acquisition device stop collecting, and then unload to the zero force state; Apply a pressure preload to each steering tie rod. Before loading, zero the force and strain on the computer, then make the data acquisition device enter the acquisition state. The maximum value of the pressure preload is the maximum value of the calibrated tension. When the applied force is close to the maximum calibrated pressure, slow down the loading speed. After reaching the maximum value of the calibrated pressure, make the data acquisition device stop collecting, and then unload to the zero force state.

4. The calibration method for bidirectional tension and compression loading of the tie rod according to claim 2, wherein: The formal tension and compression loading include: Zero the force and strain on the computer, start data acquisition by the data acquisition device, rotate the loading screw through the loading operation part to apply tension to the tie rod, and simultaneously acquire tension data and strain data. The maximum tension loading is the maximum calibration tension. Slow down the loading speed when the applied force approaches the maximum calibration tension. After reaching the maximum calibration tension, stop data acquisition by the data acquisition device, and then unload to the zero-force state; Zero the force and strain on the computer, start data acquisition by the data acquisition device, rotate the loading screw through the loading operation part to apply pressure to the tie rod, and simultaneously acquire pressure data and strain data. The maximum pressure loading is the maximum calibration pressure. Slow down the loading speed when the applied force approaches the maximum calibration pressure. After reaching the maximum calibration pressure, stop data acquisition by the data acquisition device, and then unload to the zero-force state.

5. The calibration method for bidirectional tension and compression loading of the tie rod according to claim 2, wherein: It also includes, after determining the calibration coefficient, judging the quality of the calibration according to whether the value of the linearity R obtained by fitting is close to 1. 2 ​

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