Online Dynamic Calibration Method for Torque of Dynamometer System

Abstract

The present invention specifically relates to an online dynamic torque calibration method for a dynamometer system, comprising: transferring a linear displacement to the dynamometer to cause it to rotate until a dynamometer torque sensor acquires the dynamometer's maximum torque, and recording the maximum linear displacement applied at that point; dividing the dynamometer's maximum speed range into multiple speed points, and calculating a linear displacement loading curve for each speed point based on the maximum linear displacement applied to the dynamometer at maximum torque; applying linear displacement using the linear displacement loading curves for each speed point, and collecting force and displacement values during the loading process to calculate the actual torque signal applied to the dynamometer at each speed point; measuring the torque signal of the dynamometer at each speed point using a dynamometer torque sensor, and calibrating the dynamometer torque sensor based on the actual torque signal. The present invention enables dynamic and online calibration of the torque sensor of a dynamometer system.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle development testing, and in particular to an online dynamic torque calibration method for a dynamometer system. Background Art

[0002] The electric drive system is a core component of electric vehicles, consisting of a motor controller, drive motor, and reducer. As one of the most crucial components in electric vehicle analysis and development, its performance directly impacts the overall performance of the vehicle. Therefore, during the development of electric vehicles, the testing techniques and conditions for the electric drive system are increasingly impacting vehicle development.

[0003] The operating efficiency of electric drive systems directly impacts the energy consumption and range of electric vehicles, and is therefore attracting increasing attention from major automakers and users. Efficiency test benches are the primary means of determining the efficiency of electric drive systems, and precise torque measurement and control on dynamometer systems on efficiency test benches are crucial for accurately determining this efficiency. Dynamometer system torque is typically measured using a torque sensor mounted on a test bench. Prior to measurement, online calibration of the torque sensor is crucial to ensure accurate efficiency measurement, eliminating the effects of installation and operating environment.

[0004] However, due to the lack of an online calibration system for torque sensors in dynamometer systems, existing solutions require the torque sensors to be disassembled and calibrated separately. This significantly differs from online calibration in the dynamometer system, resulting in poor calibration effectiveness. Existing solutions also utilize lever weights for online calibration of torque sensors in dynamometer systems, but these methods only allow for static calibration, and loading and unloading weights is time-consuming and labor-intensive, resulting in poor calibration consistency. Therefore, designing a device that can improve the accuracy and consistency of torque sensor calibration in dynamometer systems is an urgent technical challenge. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide an online dynamic torque calibration device for a dynamometer system, which can realize dynamic calibration and online calibration of the torque sensor of the dynamometer system, thereby improving the effectiveness and consistency of the calibration of the torque sensor of the dynamometer system, and providing important support for the efficient and accurate measurement of the efficiency of the electric drive system.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for online dynamic torque calibration of a dynamometer system, the dynamometer system comprising a dynamometer and a dynamometer torque sensor for measuring the dynamometer torque; and comprising:

[0008] S1: Loading linear displacement is transmitted to the dynamometer to make it rotate until the dynamometer torque sensor acquires the maximum torque of the dynamometer, and the maximum linear displacement at this time is recorded;

[0009] S2: Divide the maximum speed range of the dynamometer into multiple speed points, and calculate the linear displacement loading curve of each speed point based on the maximum linear displacement loaded by the dynamometer at the maximum torque;

[0010] S3: Load the linear displacement through the linear displacement loading curve at each speed point, and collect the force value and displacement value during the loading process to calculate the actual torque signal loaded to the dynamometer at each speed point;

[0011] S4: Measure the measured torque signal of the dynamometer at each speed point through the dynamometer torque sensor, and calibrate the dynamometer torque sensor with the corresponding actual torque signal.

[0012] Preferably, the linear displacement is loaded and transmitted to the dynamometer through the calibration device to cause it to rotate;

[0013] The calibration device includes:

[0014] The calibration arm is coaxially fixedly connected to the rotating shaft of the dynamometer and has the axis of the rotating shaft of the dynamometer as its rotation center;

[0015] The loading component is used to load the calibration arm with linear displacement control so that it drives the dynamometer shaft to rotate and load torque to the dynamometer shaft.

[0016] Preferably, the calibration device further includes:

[0017] The rotary transmission assembly includes a transmission shaft that can rotate freely and is coaxially arranged with the dynamometer shaft, a coupling for coaxially fixedly connecting the transmission shaft and the dynamometer shaft, and a mounting sleeve coaxially fixedly sleeved on the transmission shaft;

[0018] The calibration arm is fixedly mounted on the mounting sleeve and has the axis of the dynamometer shaft as its rotation center;

[0019] The loading assembly applies linear displacement control to the calibration arm so that it drives the transmission shaft to rotate through the mounting sleeve, and then drives the dynamometer shaft to rotate through the coupling, and loads torque to the dynamometer shaft.

[0020] Preferably, the calibration arm includes two force arm portions that are symmetrical with respect to a vertical plane of the axis of the transmission shaft;

[0021] Each arm portion of the calibration arm is projected along the axis of the transmission shaft into an isosceles trapezoidal wedge that gradually narrows in the direction away from the mounting sleeve, and the symmetry line of the isosceles trapezoidal wedge obtained by projecting the calibration arm remains perpendicular to the axis of the transmission shaft.

[0022] Preferably, the loading assembly includes an actuator for outputting linear displacement control, a force sensor and a displacement sensor for respectively collecting force values and displacement values when the actuator is loaded with linear displacement control, and a connecting fixture for connecting the calibration arm and the displacement control output end of the actuator;

[0023] The position where the calibration arm contacts the connecting fixture is the loading position when the actuator is loaded for linear displacement control;

[0024] The actuator loads a uniform linear displacement control to the calibration arm through the connecting fixture, so that the calibration arm drives the transmission shaft to rotate at a uniform speed through the mounting sleeve, and then drives the dynamometer shaft to rotate at a uniform speed through the coupling.

[0025] Preferably, the maximum rotation angle of the calibration arm at the maximum torque of the dynamometer is first calculated based on the maximum linear displacement; then the loading slope and loading period of the corresponding angle at each speed point are calculated based on the maximum rotation angle of the calibration arm, and the loading angle curve of each speed point is obtained; finally, the loading angle in the loading angle curve of each speed point is converted into the corresponding linear displacement loading, and then the linear displacement loading curve of the loading component at each speed point is generated.

[0026] Preferably, the maximum rotation angle of the calibration arm at the maximum torque of the dynamometer is calculated by the following formula:

[0027]

[0028] l1=Rcosα;

[0029]

[0030] a=2e;

[0031] b=e 2 -l 2 ;

[0032] c=(Rlcosα) 2 ;

[0033] e=ltanα+h max -R;

[0034] Where: θ max Indicates the maximum rotation angle of the calibration arm under the maximum torque of the dynamometer; h max It represents the maximum linear displacement of the loading assembly under the maximum torque of the dynamometer; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the center of rotation; l represents the horizontal distance from the loading position on the calibration arm to the center of rotation.

[0035] Preferably, the loading slope and loading period of the rotation angle corresponding to the speed point are calculated by the following formula:

[0036]

[0037]

[0038] Where: k i represents the loading slope; T i Indicates the loading cycle; n i Indicates the i-th speed point.

[0039] Preferably, the loading angle is converted into the loading displacement by the following formula:

[0040]

[0041] Where: h represents the linear displacement of the load; l represents the horizontal distance from the loading position on the calibration arm to the rotation center; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center; θ represents the rotation angle of the calibration arm under linear displacement control, that is, the loading angle.

[0042] Preferably, the actual torque signal of the load is calculated by the following formula:

[0043] M=F·cos(α+θ)·R·cosα·tanβ+F·sin(α+θ)·R·cosα;

[0044]

[0045] x=l·tanα;

[0046]

[0047] Where: M represents the actual torque signal of the load; F represents the load force value; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center; θ represents the rotation angle of the calibration arm under linear displacement control, that is, the loading angle; h represents the load displacement value; l represents the horizontal distance from the loading position on the calibration arm to the rotation center; and x represents the vertical height of the loading position.

[0048] Compared with the prior art, the torque online dynamic calibration method for the dynamometer system in the present invention has the following beneficial effects:

[0049] The present invention first records the maximum linear displacement at the dynamometer's maximum torque, then divides the speed points according to the dynamometer's maximum speed range. Combined with the maximum linear displacement calculation, a linear displacement loading curve is generated for each speed point. This allows linear displacement control to be loaded using the linear displacement loading curve, and the actual torque signal at each speed point is calculated to calibrate the dynamometer torque sensor. This allows the dynamometer torque sensor to be calibrated under various speed conditions, thus achieving dynamic calibration of the dynamometer torque. Compared to existing methods that only allow for static calibration using lever weights, this improves the consistency, efficiency, and automation of dynamometer torque calibration. Furthermore, the present invention eliminates the need to remove the dynamometer torque sensor from the dynamometer system for separate calibration, enabling online dynamometer torque calibration. This improves the effectiveness of dynamometer torque calibration compared to existing methods that require separate calibration and recalibration after removal. The present invention enables dynamic and online dynamometer torque calibration, thereby improving the effectiveness and consistency of dynamometer system torque calibration and providing important support for efficient and accurate measurement of electric drive system efficiency.

[0050] The present invention transmits a loaded linear displacement to the dynamometer to cause it to rotate (i.e., load torque). On the one hand, the present invention converts linear displacement control into rotational control, and calculates the actual torque signal transmitted to the dynamometer by the force value and displacement value during the loaded linear displacement control. That is, there is no need to set up a special new motor and torque speed sensor to load torque, there will be no new torque sensor accuracy issues, and the entire calibration process is closer to reality, thereby further improving the accuracy of the dynamometer torque calibration. On the other hand, the method of loading linear displacement control of the present invention does not increase the axial size of the calibration device, which is conducive to simplifying the structure of the calibration device, thereby improving the installation convenience of the calibration device and the practicality of the dynamometer torque calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to make the purpose, technical solutions and advantages of the invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings, in which:

[0052] Figure 1 This is the logic block diagram of the torque online dynamic calibration method;

[0053] Figure 2 It is a structural diagram of the calibration device;

[0054] Figure 3 and Figure 4 It is a front view and a top view of the calibration device;

[0055] Figure 5 is a side sectional view of the calibration device;

[0056] Figure 6 It is the structural diagram of the calibration arm;

[0057] Figure 7 is the equivalent structure diagram of the calibration arm;

[0058] Figure 8 and Figure 9 All are schematic diagrams of equivalent motion of the calibration arm;

[0059] Figure 10 Schematic diagram of the relationship between loading angle, loading displacement and time.

[0060] The figure marks in the drawings of the specification include: base 1, calibration support 2, dynamometer system 3, dynamometer shaft 31, dynamometer torque sensor 4, calibration arm 5, force arm portion 51, mounting hole 52, through hole 53, actuator 6, connecting fixture 7, rotary transmission assembly 8, bearing seat 81, transmission shaft 82, coupling 83, mounting sleeve 84, slide rail 91, movable slider 92. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0062] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition or explanation in subsequent figures. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicate positions or relationships based on the positions or relationships shown in the figures, or the positions or relationships in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and are not to be construed as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that a component is absolutely horizontal or overhanging, but rather may be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather may be slightly tilted. In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0063] The following is a further detailed description through specific implementation methods:

[0064] Example:

[0065] This embodiment discloses a method for online dynamic torque calibration of a dynamometer system.

[0066] like Figure 1 As shown, a method for online dynamic torque calibration of a dynamometer system is provided. The dynamometer system includes a dynamometer and a dynamometer torque sensor for measuring the dynamometer torque; and includes:

[0067] In this embodiment, the rotating shaft of the dynamometer is connected to the dynamometer torque sensor via a coupling.

[0068] S1: Loading linear displacement is transmitted to the dynamometer to make it rotate until the dynamometer torque sensor acquires the maximum torque of the dynamometer, and the maximum linear displacement at this time is recorded;

[0069] S2: Divide the maximum speed range of the dynamometer into multiple speed points, and calculate the linear displacement loading curve of each speed point based on the maximum linear displacement loaded by the dynamometer at the maximum torque;

[0070] S3: Load the linear displacement through the linear displacement loading curve at each speed point, and collect the force value and displacement value during the loading process to calculate the actual torque signal loaded to the dynamometer at each speed point;

[0071] S4: Measure the measured torque signal of the dynamometer at each speed point through the dynamometer torque sensor, and calibrate the dynamometer torque sensor with the corresponding actual torque signal.

[0072] In this embodiment, the actual torque signal is compared with the measured torque signal to determine whether the linearity, return error, and sensitivity of the torque sensor of the dynamometer system are within a reasonable range (the sensor's factory technical parameters). Corrections are then made based on the comparison signal. Torque sensor calibration can be achieved using existing, proven calibration solutions.

[0073] In order to better achieve online dynamic calibration of dynamometric torque, this embodiment discloses the following calibration scheme:

[0074] First, a straight line fitting is performed with the measured torque signal of the dynamometer torque sensor at each speed point as the horizontal coordinate and the actual torque signal of the load as the vertical coordinate to obtain the corresponding intercept and slope; then the intercept and slope corresponding to each speed point are averaged to obtain the intercept and slope of the entire calibration process; finally, the measured torque signal of the dynamometer torque sensor is corrected using the intercept and slope parameters of the entire calibration process to complete the torque calibration of the dynamometer system.

[0075] The present invention first records the maximum linear displacement at the dynamometer's maximum torque, then divides the speed points according to the dynamometer's maximum speed range. Combined with the maximum linear displacement calculation, a linear displacement loading curve is generated for each speed point. This allows linear displacement control to be loaded using the linear displacement loading curve, and the actual torque signal at each speed point is calculated to calibrate the dynamometer torque sensor. This allows the dynamometer torque sensor to be calibrated under various speed conditions, thus achieving dynamic calibration of the dynamometer torque. Compared to existing methods that only allow for static calibration using lever weights, this improves the consistency, efficiency, and automation of dynamometer torque calibration. Furthermore, the present invention eliminates the need to remove the dynamometer torque sensor from the dynamometer system for separate calibration, enabling online dynamometer torque calibration. This improves the effectiveness of dynamometer torque calibration compared to existing methods that require separate calibration and recalibration after removal. The present invention enables dynamic and online dynamometer torque calibration, thereby improving the effectiveness and consistency of dynamometer system torque calibration and providing important support for efficient and accurate measurement of electric drive system efficiency.

[0076] During actual dynamometer torque calibration, a dedicated new motor (dynamometer) is typically required to apply rotational control (i.e., torque) to the dynamometer. However, this new motor requires a corresponding torque and speed sensor, significantly increasing the cost of dynamometer torque calibration. This also creates difficulties in ensuring the accuracy of the new motor's torque and speed sensor, introducing new accuracy issues. Furthermore, directly applying rotational control to the new motor significantly increases the axial dimensions of the calibration device, making it difficult to install.

[0077] The present invention transmits a loaded linear displacement to the dynamometer to cause it to rotate (i.e., load torque). On the one hand, the present invention converts linear displacement control into rotational control, and calculates the actual torque signal transmitted to the dynamometer by the force value and displacement value during the loaded linear displacement control. That is, there is no need to set up a special new motor and torque speed sensor to load torque, there will be no new torque sensor accuracy issues, and the entire calibration process is closer to reality, thereby further improving the accuracy of the dynamometer torque calibration. On the other hand, the method of loading linear displacement control of the present invention does not increase the axial size of the calibration device, which is conducive to simplifying the structure of the calibration device, thereby improving the installation convenience of the calibration device and the practicality of the dynamometer torque calibration.

[0078] Combine Figure 2 、 Figure 3 、 Figure 4 As shown, the calibration device includes:

[0079] A base 1 for mounting the dynamometer system 3;

[0080] In this embodiment, the dynamometer system 3 includes a dynamometer and a dynamometer torque sensor 4 for measuring the dynamometer torque; the dynamometer shaft 31 is connected to the dynamometer torque sensor 4 via a coupling.

[0081] a calibration support 2, provided on the base at a side corresponding to the dynamometer shaft 31;

[0082] A rotary transmission assembly 8, disposed on the calibration support and in transmission connection with the rotating shaft 31 of the dynamometer;

[0083] The calibration arm 5 is in transmission connection with the rotary transmission assembly;

[0084] The loading component is arranged on the calibration support and is used to load the calibration arm with linear displacement control so that it drives the rotary transmission component to convert the loaded linear displacement control into rotation control and transmit torque to the rotating shaft of the dynamometer.

[0085] In this embodiment, the linear displacement control refers to driving the calibration arm to perform linear motion.

[0086] This invention essentially applies vertical linear displacement control to the calibration arm, driving it to perform vertical linear motion. When calibration is required at the same speed, linear displacement control enables the calibration arm to rotate at a constant speed, enabling dynamic torque calibration at a fixed speed and eliminating the effects of inertial torque.

[0087] In other preferred embodiments, the loading assembly can also apply force control only to the calibration arm in the vertical direction (i.e., the calibration arm does not move). Force control directly derives torque from the applied force. When a fixed speed is not required, force control can be used for calibration, but slow loading is required to avoid the influence of inertial torque. Force control is similar to existing static calibration.

[0088] The rotation angle (angle) of the calibration arm will not exceed 30°.

[0089] like Figure 5 As shown, the rotary transmission assembly 8 includes a transmission shaft 82 rotatably set on the calibration support and coaxially set with the rotating shaft of the dynamometer, a coupling 83 for coaxially fixedly connecting the transmission shaft 82 and the rotating shaft 31 of the dynamometer, a mounting sleeve 84 coaxially fixedly sleeved on the transmission shaft, and a bearing seat 81 fixedly set on the calibration support and a bearing with an outer ring fixedly mounted on the bearing seat; the transmission shaft 82 is coaxially fixedly connected to the inner ring of the bearing.

[0090] The calibration arm 5 is fixedly mounted on the mounting sleeve 84 and has the axis of the transmission shaft as its rotation center;

[0091] In this embodiment, the calibration arm is fixed on the mounting sleeve by means of bolts.

[0092] The loading assembly applies linear displacement control to the calibration arm so that it drives the transmission shaft to rotate through the mounting sleeve, and then transmits torque to the shaft of the dynamometer through the coupling.

[0093] The present invention applies linear displacement control to the calibration arm through the loading component, so that the calibration arm can drive the transmission shaft to rotate at a uniform speed through the installation sleeve and transmit torque to the shaft of the dynamometer through the coupling, that is, the linear motion loaded by the loading component can be converted into the uniform rotation of the rotary transmission component, thereby better realizing the dynamic calibration of the dynamometer torque, and the rotary transmission component will not produce structural interference with the dynamometer system, and the rotation control loaded to the dynamometer after conversion makes the dynamometer torque calibration process closer to reality, thereby further improving the consistency, efficiency and automation of the dynamometer torque calibration.

[0094] The present invention applies linear displacement control to the calibration arm through a loading assembly. The calibration arm drives the transmission shaft to rotate at a constant speed through a mounting sleeve and transmits torque to the dynamometer's shaft through a coupling. This converts the linear motion applied by the loading assembly into the uniform rotation of the rotary transmission assembly. On the one hand, the present invention converts linear displacement control into rotational control, and then calculates the actual torque signal transmitted to the dynamometer by the force and displacement values during the loading linear displacement control to achieve torque calibration of the dynamometer. This eliminates the need for a dedicated dynamometer motor and torque-speed sensor to apply torque, and does not create new torque sensor accuracy issues. This reduces the structural complexity and cost of the calibration device, thereby helping to improve the accuracy of the dynamometer torque calibration. On the other hand, the present invention's method of loading linear displacement control does not increase the axial size of the calibration device, which is conducive to simplifying the calibration device structure, thereby improving the installation convenience of the calibration device and helping to improve the practicality of the dynamometer torque calibration.

[0095] The present invention installs the transmission shaft through the structure of the bearing seat and the bearing, so that the transmission shaft can rotate freely, and can better convert the linear displacement control loaded by the loading component into rotation control, thereby ensuring the torque calibration effect of the dynamometer.

[0096] Combine Figure 6 As shown, a mounting hole 52 adapted to the outer peripheral side of the mounting sleeve is opened in the middle of the calibration arm 5 , and the calibration arm 5 is coaxially fixedly mounted on the outer peripheral side of the mounting sleeve 84 through the mounting hole 52 .

[0097] In this embodiment, the calibration arm is fixed on the mounting sleeve by means of bolts.

[0098] The calibration arm 5 includes two arm portions 51 symmetrically arranged in a plane perpendicular to the axis of the transmission shaft; each arm portion 51 of the calibration arm 5 is projected along the axis of the transmission shaft as an isosceles trapezoidal wedge (e.g., Figure 6 As shown), and the symmetry line of the isosceles trapezoidal wedge obtained by the projection of the calibration arm is perpendicular to the axis of the transmission shaft, that is, the symmetry line of the isosceles trapezoidal wedge passes through the rotation center (as shown Figure 7 shown).

[0099] During actual application, the applicant found that when the calibration arm drives the rotating transmission assembly, its own gravity will affect the rotation of the transmission shaft and the dynamometer shaft, thereby affecting the torque calculation during the calibration process, resulting in poor accuracy of the dynamometer torque online calibration.

[0100] By configuring the calibration arm as two symmetrical force arms in a plane perpendicular to the axis of the transmission shaft, the present invention ensures balance when the calibration arm drives the rotating transmission assembly to rotate at a constant speed. This minimizes the effect of the calibration arm's gravity on torque calculations during the calibration process, thereby helping to improve the accuracy of online dynamometer torque calibration. Furthermore, the present application configures the calibration arm to have a specific wedge angle and project as an isosceles trapezoidal wedge, further reducing the effect of the calibration arm's gravity on the calibration process, thereby helping to improve the accuracy and practicality of online dynamometer torque calibration.

[0101] The calibration arm 5 is provided with a plurality of through holes 53 spaced apart in a direction perpendicular to the axis of the mounting hole 52 .

[0102] The present invention provides through holes arranged at intervals on the calibration arm, which can further reduce the weight of the calibration arm and minimize the influence of the gravity of the calibration arm on the calibration process, while also saving the manufacturing materials and costs of the calibration arm.

[0103] In a specific implementation process, the loading assembly includes an actuator 6 (hydraulic servo actuator, an existing hydraulic servo linear motor can be selected) fixedly mounted on the calibration support and used to output linear displacement control, a high-precision force sensor and a displacement sensor for respectively collecting the force value and displacement value of the actuator 6 when loading linear displacement control, and a connecting fixture 7 for connecting the calibration arm 5 and the displacement control output end of the actuator 6;

[0104] The position where the calibration arm 5 contacts the connecting fixture 7 is the loading position of the actuator 6 when loading the linear displacement control;

[0105] The contact between the connecting fixture 7 and the calibration arm 5 is a needle rolling contact, which facilitates the free rotation of the calibration arm.

[0106] In this embodiment, the needle roller rolling contact is an existing contact method.

[0107] The actuator applies uniform linear displacement control to the calibration arm through the connecting fixture, so that the calibration arm drives the transmission shaft to rotate at a uniform speed through the mounting sleeve, and then transmits torque to the shaft of the dynamometer through the coupling.

[0108] In actual application, the dynamometer needs to be braked and fixed; at the same time, the calibration arm needs to be adjusted to the horizontal position through the actuator, and the force sensor and displacement sensor need to be adjusted to zero.

[0109] The loading assembly of the present invention, with the aforementioned structure, outputs a vertical linear displacement control through an actuator and transmits it to the calibration arm via a connecting fixture, thereby loading the calibration arm with the vertical linear displacement control. This allows the calibration arm to drive the transmission shaft to rotate at a constant speed via the mounting sleeve and transmit torque to the dynamometer's shaft via a coupling. This converts the linear motion loaded by the loading assembly into a uniform rotation of the rotational transmission assembly, thereby better achieving dynamic calibration of the dynamometer's torque and ensuring the effectiveness of the dynamometer's torque calibration. Furthermore, the loading assembly of the present invention does not interfere with the dynamometer system, and the rotational control loaded onto the dynamometer after conversion makes the dynamometer's torque calibration process more realistic, thereby further improving the consistency, efficiency, and automation of the dynamometer's torque calibration.

[0110] During the specific implementation process, the dynamometer torque online calibration device also includes:

[0111] The slide rail 91 is fixedly provided on the side of the base corresponding to the dynamometer shaft, and the sliding direction is facing the dynamometer;

[0112] The movable slider 92 is slidably arranged on the slide rail and is used for fixing the calibration support.

[0113] The present invention can drive the entire calibration device to move on the base toward or away from the dynamometer system through the structure of the slide rail and the movable slider, thereby facilitating the installation and disassembly of the calibration device.

[0114] Based on the above calibration device, the present invention generates a linear displacement loading curve at each speed point in the following manner:

[0115] 1) Load the linear displacement control by the calibration device until the dynamometer torque sensor collects the maximum torque T of the dynamometer max Nearby, record the maximum linear displacement h loaded by the calibration device at this time max ;

[0116] 2) According to the maximum linear displacement h maxCalculate the maximum rotation angle θ of the dynamometer shaft (calibration arm) max ;

[0117] 3) Divide multiple speed points n from the maximum speed range of the dynamometer i (i=0,1,2,…,m,m>5);

[0118] 4) Based on the maximum rotation angle θ max Calculate each speed point n i The loading slope and loading cycle corresponding to the rotation angle are obtained, and the speed point n is obtained. i Loading angle curve;

[0119] 5) Set each speed point n i The loading angle in the loading angle curve is converted into the corresponding linear displacement load, and then the linear displacement loading curve of each speed point is generated (such as Figure 10 shown).

[0120] In this embodiment, the actuator applies a linear displacement to the calibration arm, causing it to rotate the rotary transmission assembly. This also causes the calibration arm to rotate. Therefore, each loaded angle of the calibration arm has a corresponding linear displacement. The present invention converts the loading angle curve into a corresponding linear displacement loading curve, which is used to control the actuator's output linear displacement.

[0121] The present invention first records the maximum displacement value and calculates the maximum rotation angle at the maximum torque of the dynamometer, then divides the speed points according to the maximum speed range of the dynamometer, and calculates and generates the loading angle curve of each speed point, and finally converts the loading angle curve of each speed point into a linear loading displacement curve of a calibration device, so that the calibration device can realize the calibration of the dynamometer torque sensor by loading the linear displacement control through the linear loading displacement curve and calculating the actual torque signal at each speed point, thereby effectively calibrating the dynamometer torque sensor at various speeds, thereby better realizing the dynamic calibration of the dynamometer torque.

[0122] However, since the calibration arm of the present invention has a wedge angle, the relationship between the vertical loading force and the loading torque, as well as the vertical loading velocity and the loading angular velocity is no longer a simple linear and rotational relationship, but is relatively complex. The following is a dynamic and kinematic analysis of the loading system to analyze and derive the relationship between linear loading and rotational loading.

[0123] Combine Figure 7 and Figure 8 The formula parameters designed by the present invention are explained.

[0124] like Figure 7 As shown in , the calibration arm is projected to form an isosceles trapezoidal wedge abcd. Figure 8As shown in the figure, the calibration arm rotates. The solid isosceles trapezoidal wedge abcd represents the initial horizontal position of the calibration arm. Assuming that the vertical force F of the actuator is applied upward, the calibration arm rotates counterclockwise by an angle θ, as shown in the figure. Figure 8 At the position of the isosceles trapezoidal wedge a′b′c′d′ in the dotted line, the vertical distance moved by point D is h. The force F at the calibration arm's load point (loading position) at point D can be decomposed into a force component F1 perpendicular to the lower edge of the calibration arm and a force component F2 along the lower edge of the calibration arm. The torque generated around the rotation center is counterclockwise (counterclockwise is defined as positive). That is:

[0125] α: represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm.

[0126] R: represents the distance between the lower base of the isosceles trapezoidal wedge obtained by the projection of the calibration arm and the axis (rotation center) of the transmission shaft, that is, half the length of the lower base of the isosceles trapezoidal wedge ( Figure 7 (length from a to O in the figure).

[0127] D: Indicates the loading position of the actuator, that is, the point where the actuator contacts the calibration arm through the connecting fixture.

[0128] l: represents the horizontal distance from the actuator loading position to the rotation center, i.e. Figure 7 The length from a to D′.

[0129] x: represents the vertical height of the actuator loading position, i.e. Figure 7 The length from D to D′.

[0130] θ: represents the rotation angle of the calibration arm under displacement control, that is, the loading angle.

[0131] h: represents the displacement value of the actuator loading, that is, Figure 7 Medium D to D″ length.

[0132] Combine Figure 7 and Figure 8 The following analysis and deduction are made:

[0133] The torque generated by the component force F1 is as shown in formula (1):

[0134] M1=F1·R1 (R1 represents Figure 8 Length from E to D″) (1)

[0135] The torque generated by the component force F2 is as shown in formula (2):

[0136] M2=F2·R2 (R2 represents Figure 8 Length from E to O) (2)

[0137] The magnitudes of the force components F1 and F2 are as shown in equations (3) and (4):

[0138] F1=F·cos(α+θ) (3)

[0139] F2=F·sin(α+θ) (4)

[0140] The force arms R2 and R1 are calculated as shown in formula (5) (6):

[0141] R2=R·cosα (5)

[0142] R1=R2·tanβ (6)

[0143] Where β represents Figure 8 The size of the angle ∠D″OE in the equation is as follows:

[0144]

[0145] where x and θ are expressed by equations (8) and (9).

[0146] x=l·tanα (8)

[0147]

[0148] Therefore, the actual torque signal M around the rotation center is as shown in formula (10):

[0149] M=M1+M2=F·cos(α+θ)·R·cosα·tanβ+F·sin(α+θ)·R·cosα (10)

[0150] Where: M represents the actual torque signal of the load; F represents the force value loaded by the actuator; M1 represents the torque generated by the component F1 of the loaded force F perpendicular to the lower edge of the calibration arm; M2 represents the torque generated by the component F2 of the loaded force F along the lower edge of the calibration arm; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance between the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm and the axis (rotation center) of the transmission shaft, that is, half the length of the lower base of the isosceles trapezoidal wedge; θ represents the rotation angle of the calibration arm under displacement control, that is, the loading angle; h represents the displacement value loaded by the actuator; A represents the horizontal distance from the actuator loading position to the rotation center; l represents the horizontal distance from the actuator loading position to the rotation center; x represents the vertical height of the actuator loading position.

[0151] When the vertical force F is applied downward on the actuator, the calibration arm rotates clockwise as a whole, and the force point of the calibration arm is at point D on the upper edge of the calibration arm. The calculation formula for the loading torque can be derived to be the same as that of formula (10) (torque and rotation angle are positive counterclockwise and negative clockwise).

[0152] For the relationship between displacement and rotation angle under vertical loading, such as Figure 9 As shown, the initial position of the calibration arm is horizontal (isosceles trapezoidal wedge abcd in the figure), and the horizontal distance AB of the actuator loading position is l (i.e. Figure 8 aD′ in the vertical direction), the vertical loading displacement DC of the actuator is h (i.e. Figure 8 DD″), the calibration arm rotates counterclockwise at an angle ∠GOF of θ. Figure 9 The dotted line isosceles trapezoidal wedge a′b′c′d′ is shown. After rotating through point O, the perpendicular line of the lower edge of the calibration arm intersects at point E, and the extension line of CE intersects the initial vertical coordinate line at point A.

[0153] Depend on Figure 9 It can be seen that the rotation angle θ can be expressed as formula (11):

[0154] θ=∠AOE-α=∠CAB-α (11)

[0155] Assume that the length of OE is l1, the length of AE is l2, the length of EC is l3, the length of OA is l4, and the length of CB is l5, then:

[0156]

[0157] l1=Rcosα (13)

[0158] l4 2 =l1 2 +l2 2 (14)

[0159] l1 / l=l2 / l5 (15)

[0160] h=l5+R-ltanα-l4 (16)

[0161] From equations (12) to (16), it can be obtained that when the rotation angle θ is set, the displacement h required to be loaded is:

[0162]

[0163] Where: h represents the displacement value of the actuator loading; l represents the horizontal distance from the actuator loading position to the rotation center; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance between one end of the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm and the axis (rotation center) of the transmission shaft, that is, half the length of the lower base of the isosceles trapezoidal wedge; θ represents the rotation angle of the calibration arm under displacement control, that is, the loading angle.

[0164] Similarly, it can be deduced that when loading downward, the calibration arm rotates clockwise, and the rotation angle θ is a negative value, which can be calculated using formula (18):

[0165]

[0166] Specifically:

[0167] The maximum rotation angle of the calibration device, i.e. the maximum rotation angle of the calibration arm, is calculated using the following formula:

[0168]

[0169] l1=Rcosα;

[0170]

[0171] a=2e;

[0172] b=e 2 -l 2 ;

[0173] c=(Rlcosα) 2 ;

[0174] e=ltanα+h max -R;

[0175] Where: θ max Indicates the maximum rotation angle of the calibration arm under the maximum loading torque of the dynamometer; h max It represents the maximum linear displacement of the actuator under the maximum loading torque of the dynamometer; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from one end of the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the center of rotation, that is, half the length of the lower base of the isosceles trapezoidal wedge; l represents the horizontal distance from the loading position of the actuator to the center of rotation.

[0176] The loading slope and loading period of the rotation angle corresponding to the speed point are calculated using the following formula:

[0177]

[0178]

[0179] Where: k i represents the loading slope; T i Indicates the loading cycle; n i Indicates the i-th speed point.

[0180] The loading angle is converted into loading displacement using the following formula:

[0181]

[0182] Where: h represents the displacement value of the actuator loading; l represents the horizontal distance from the actuator loading position to the rotation center; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; α represents the distance from one end of the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center, that is, half the length of the lower base of the isosceles trapezoidal wedge; θ represents the rotation angle of the calibration arm under displacement control, that is, the loading angle.

[0183] The actual torque signal of the load is calculated using the following formula:

[0184] M=F·cos(α+θ)·R·cosα·tanD+F·sin(α+θ)·R·cosα;

[0185]

[0186] x=l·tanα;

[0187]

[0188] Where: M represents the actual torque signal of the load; F represents the force value loaded by the actuator; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center; θ represents the rotation angle of the calibration arm under displacement control, that is, the loading angle; h represents the displacement value loaded by the actuator; l represents the horizontal distance from the actuator loading position to the rotation center; and x represents the vertical height of the actuator loading position.

[0189] In order to minimize the influence of the gravity of the calibration arm on the calibration process, the present invention sets the calibration arm to a structure with a certain wedge angle and projected as an isosceles trapezoidal wedge block. However, due to the wedge angle of the calibration arm, the relationship between the vertical loading force and the loading torque, as well as the vertical loading velocity and the loading angular velocity, is no longer a simple linear and rotational relationship, and the relevant data cannot be accurately calculated during the actual calibration process. To address this problem, the present invention calculates the relationship between the loading force and torque of the calibration arm and the relationship between the loading displacement and the rotation angle, so that the calculation of various parameters in the dynamic calibration process of the dynamometer torque can be effectively realized based on the calibration arm with a wedge angle, thereby effectively ensuring the accuracy of the dynamometer torque calibration while further improving the consistency, efficiency and automation of the dynamometer torque calibration.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for online dynamic torque calibration of a dynamometer system, wherein the dynamometer system comprises a dynamometer and a dynamometer torque sensor for measuring the dynamometer torque; characterized in that: include: S1: Loading linear displacement is transmitted to the dynamometer to make it rotate until the dynamometer torque sensor acquires the maximum torque of the dynamometer, and the maximum linear displacement at this time is recorded; S2: Divide the maximum speed range of the dynamometer into multiple speed points, and calculate the linear displacement loading curve of each speed point based on the maximum linear displacement loaded by the dynamometer at the maximum torque; S3: Load the linear displacement through the linear displacement loading curve at each speed point, and collect the force value and displacement value during the loading process to calculate the actual torque signal loaded to the dynamometer at each speed point; S4: Measure the measured torque signal of the dynamometer at each speed point through the dynamometer torque sensor, and calibrate the dynamometer torque sensor with the corresponding actual torque signal.

2. The method for online dynamic torque calibration of a dynamometer system according to claim 1, wherein: In step S1, a linear displacement is loaded and transmitted to the dynamometer through a calibration device to cause it to rotate; The calibration device includes: The calibration arm is coaxially fixedly connected to the rotating shaft of the dynamometer and has the axis of the rotating shaft of the dynamometer as its rotation center; The loading component is used to load the calibration arm with linear displacement control so that it drives the dynamometer shaft to rotate and load torque to the dynamometer shaft.

3. The method for online dynamic torque calibration of a dynamometer system according to claim 2, wherein: The calibration device also includes: The rotary transmission assembly includes a transmission shaft that can rotate freely and is coaxially arranged with the dynamometer shaft, a coupling for coaxially fixedly connecting the transmission shaft and the dynamometer shaft, and a mounting sleeve coaxially fixedly sleeved on the transmission shaft; The calibration arm is fixedly mounted on the mounting sleeve and has the axis of the dynamometer shaft as its rotation center; The loading assembly applies linear displacement control to the calibration arm so that it drives the transmission shaft to rotate through the mounting sleeve, and then drives the dynamometer shaft to rotate through the coupling, and loads torque to the dynamometer shaft.

4. The method for online dynamic torque calibration of a dynamometer system according to claim 3, wherein: The calibration arm includes two force arm parts that are symmetrical with respect to the vertical plane of the axis of the transmission shaft; Each arm portion of the calibration arm is projected along the axis of the transmission shaft into an isosceles trapezoidal wedge that gradually narrows in the direction away from the mounting sleeve, and the symmetry line of the isosceles trapezoidal wedge obtained by projecting the calibration arm remains perpendicular to the axis of the transmission shaft.

5. The method for online dynamic torque calibration of a dynamometer system according to claim 4, wherein: The loading assembly includes an actuator for outputting linear displacement control, a force sensor and a displacement sensor for respectively collecting force values and displacement values when the actuator is loaded with linear displacement control, and a connecting fixture for connecting the calibration arm and the displacement control output end of the actuator; The position where the calibration arm contacts the connecting fixture is the loading position when the actuator is loaded for linear displacement control; The actuator loads a uniform linear displacement control to the calibration arm through the connecting fixture, so that the calibration arm drives the transmission shaft to rotate at a uniform speed through the mounting sleeve, and then drives the dynamometer shaft to rotate at a uniform speed through the coupling.

6. The method for online dynamic torque calibration of a dynamometer system according to claim 4, wherein: In step S2, the maximum rotation angle of the calibration arm at the maximum torque of the dynamometer is first calculated based on the maximum linear displacement; then, the loading slope and loading period of the corresponding angle at each speed point are calculated based on the maximum rotation angle of the calibration arm, and the loading angle curve of each speed point is obtained; finally, the loading angle in the loading angle curve of each speed point is converted into the corresponding linear displacement loading, and then the linear displacement loading curve of the loading component at each speed point is generated.

7. The method for online dynamic torque calibration of a dynamometer system according to claim 6, wherein: The maximum rotation angle of the calibration arm at the maximum torque of the dynamometer is calculated using the following formula: l1=Rcosα; a=2e; b=e 2 -l 2 ; c=(Rl cosα) 2 ; e=ltanα+h max -R; Where: θ max Indicates the maximum rotation angle of the calibration arm under the maximum torque of the dynamometer; h max It represents the maximum linear displacement of the loading assembly under the maximum torque of the dynamometer; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the center of rotation; l represents the horizontal distance from the loading position on the calibration arm to the center of rotation.

8. The method for online dynamic torque calibration of a dynamometer system according to claim 7, wherein: The loading slope and loading period of the rotation angle corresponding to the speed point are calculated using the following formula: Where: k i represents the loading slope; T i Indicates the loading cycle; n i Indicates the i-th speed point.

9. The method for online dynamic torque calibration of a dynamometer system according to claim 8, wherein: The loading angle is converted into loading displacement using the following formula: Where: h represents the linear displacement of the load; l represents the horizontal distance from the loading position on the calibration arm to the rotation center; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center; θ represents the rotation angle of the calibration arm under linear displacement control, that is, the loading angle.

10. The method for online dynamic torque calibration of a dynamometer system according to claim 6, wherein: In step S3, the actual torque signal of the load is calculated using the following formula: M=F·cos(α+θ)·R·cosα·tanβ+F·sin(α+θ)·R·cosα; x=l·tanα; Where: M represents the actual torque signal of the load; F represents the load force value; α represents the wedge angle of the isosceles trapezoidal wedge obtained by projecting the calibration arm; R represents the distance from the lower base of the isosceles trapezoidal wedge obtained by projecting the calibration arm to the rotation center; θ represents the rotation angle of the calibration arm under linear displacement control, that is, the loading angle; h represents the load displacement value; l represents the horizontal distance from the loading position on the calibration arm to the rotation center; and x represents the vertical height of the loading position.

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