Torque measuring method and device based on cylinder driving
Through the torque measurement method based on cylinder drive, the relative torsion angle between the two sections on the rotating shaft is measured, which solves the measurement error problem caused by material properties and strain characteristics in the traditional method, and achieves higher accuracy and real-time torque monitoring.
Patent Information
- Application Number
- CN202411523790.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-03-11
AI Technical Summary
Traditional torque measurement methods require consideration of the material properties, shape and strain characteristics of the object, which may lead to measurement errors.
Torque measurement method based on cylinder drive is used to obtain torque through cylinder system design, cylinder control, installation sensors and torque calculations, and the relative torsion angle between any two sections is measured.
More accurate torque measurement is achieved, errors caused by material properties and strain characteristics are reduced, and torque changes on the rotating shaft can be accurately monitored in real time.
Smart Images
Figure CN119595149A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of torque measurement, and in particular to a method and device for measuring torque based on cylinder drive. Background Art
[0002] Torque is a special moment that causes an object to rotate. The torque of an engine refers to the torque output by the engine from the crankshaft end. Under the condition of fixed power, it is inversely proportional to the engine speed. The faster the speed, the smaller the torque, and vice versa. Torque can cause an object to rotate around its axis of rotation. When an external force acts on an object, if the force does not pass through the center of gravity of the object and creates a tendency to cause the object to rotate, then torque will be generated. The magnitude of the torque depends on the magnitude of the force and the distance from the point of action to the axis of rotation.
[0003] However, traditional torque measurement methods usually use the load subdivision method, which calculates the torque by applying a known load to the rotating shaft and measuring the deformation or strain generated under this load. Strain gauges or pressure sensors are usually used for measurement. The load subdivision method usually relies on the deformation or strain generated by the force on the object to measure the torque, which means that the material properties, shape and strain characteristics of the object need to be considered during the measurement process, which may be affected by these factors and lead to measurement errors. Summary of the invention
[0004] In view of the shortcomings of the prior art, the present invention provides a torque measurement method and device based on cylinder drive, which solves the problem that the traditional torque measurement method needs to take into account the material properties, shape and strain characteristics of the object during the measurement process, and may be affected by these factors and cause measurement errors.
[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a method and device for measuring torque based on cylinder drive, comprising the following specific steps:
[0006] Step 1: Cylinder system design: Design a cylinder system with one port connected to the air source and the other port connected to the device that needs to measure torque;
[0007] Step 2: Cylinder control: Control the air source to control the movement of the cylinder piston, and control the force applied by the cylinder by controlling the air pressure in the air source;
[0008] Step 3: Install the sensor: Install the sensor or load cell on the piston of the cylinder to measure the force applied by the cylinder;
[0009] Step 4: Torque calculation: The torque is obtained by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section.
[0010] Preferably, double-acting cylinders need to be selected in step one because they can apply force in two directions and can control the speed and position of the cylinder; and appropriate cylinder specifications need to be selected, including cylinder diameter, stroke and load-bearing capacity, diameter (D): usually an appropriate diameter is selected to provide the required force, stroke (S): the stroke should be long enough to provide the required displacement and take into account the space for sensor installation, maximum working pressure (P): ensure that the maximum working pressure of the cylinder is not lower than the working pressure required by the system; ensure that the pressure provided by the air source is stable and sufficient to meet the operating requirements of the cylinder; cylinder connection: connect the other port of the cylinder to the device that needs to measure torque to ensure that the force applied by the cylinder can be transmitted to the device being measured.
[0011] Preferably, in step 2, an air pressure regulating valve is installed on the air supply pipeline to adjust the pressure of the air source, thereby controlling the force applied by the cylinder. The air supply pipeline is connected to the air inlet of the cylinder through the cylinder body of the cylinder, and the connection is ensured to be tight to prevent gas leakage. The pressure of the air source is controlled by adjusting the air pressure regulating valve. Increasing the air pressure will increase the force applied by the cylinder, while reducing the air pressure will reduce the force applied by the cylinder. The air pressure is adjusted as needed to achieve the desired torque application effect, and the output data of the air pressure sensor is monitored to ensure that the air pressure regulation and the operation of the cylinder are as expected and can achieve the desired torque application effect.
[0012] Preferably, the sensor in step three is a variable area capacitive sensor. When determining the installation position of the sensor, it is necessary to consider the motion trajectory of the piston and the structure of the cylinder to ensure that the sensor can accurately measure the applied force and will not be damaged or interfered with. The calibration process requires the use of a known load and recording the output value of the sensor. The sensor is calibrated using a standard load or pressure gauge, and then the parameters of the sensor are adjusted according to the calibration curve. During the testing and verification stage, different loads are used to test the response of the sensor and verify the stability and accuracy of its output. Different forces are applied to simulate different torques, and the output values of the sensor are recorded for analysis and verification.
[0013] Preferably, the capacitive torque sensor is a flexible thin sheet consisting of a moving electrode plate and a static electrode plate, the static electrode plate is composed of two electrode plates A and B with the same structure and size, and the moving electrode plate is composed of multiple groups of parallel electrodes connected at both ends, these electrodes have the same structural size and are arranged equidistantly, and the spacing between them is equal to the width of the electrode.
[0014] Preferably, the calculation method in step 4 is that when the rotating shaft is subjected to a torsional load, it will cause deformation of the shaft, which is manifested as relative torsion of two sections at different positions on the shaft, forming a torsion angle. The more obvious the torsional deformation, the larger the torsion angle. L (m) is the length of the shaft, R (m) is the radius of the shaft, T (Nm) is the torque, γ is the shear strain, and φ (rad) is the relative torsion angle of the two sections. For the two ends of the rotating shaft with a distance of dx (m), the relative torsion angle dφ (rad), the shear elastic modulus G (Pa), the polar moment of inertia Ip (m4) and the torque T satisfy the following relationship. For equal radius axes, it can be obtained by integrating along the axis: Therefore, the torque can be obtained by measuring the relative torsion angle between any two sections, which can be regarded as the angular displacement of one section relative to the other.
[0015] The present invention provides a method and device for measuring torque based on cylinder drive, which has the following beneficial effects:
[0016] 1. The present invention monitors and controls the torque driven by the cylinder through cylinder system design, cylinder control, sensor installation, and torque calculation. Better quality control can be achieved during the production process, thereby ensuring that the product meets the standards and reducing the number of defective products caused by torque deviation.
[0017] 2. The present invention can provide high-precision torque measurement through a variable area capacitive sensor, and obtain torque by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section, thereby achieving the effect of being able to accurately monitor the torque changes on the rotating shaft in real time. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a flow chart of the method of the present invention;
[0019] Figure 2 It is a schematic diagram of the principle of the flat plate capacitor of the present invention;
[0020] Figure 3 It is a schematic diagram of the torsion change of the rotating shaft of the present invention. DETAILED DESCRIPTION
[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0022] Please refer to the attached Figure 1 - Attachment Figure 3The embodiment of the present invention provides a torque measurement method based on cylinder drive, comprising the following specific steps:
[0023] Step 1: Cylinder system design: Design a cylinder system with one port connected to the air source and the other port connected to the device that needs to measure torque;
[0024] Step 2: Cylinder control: Control the air source to control the movement of the cylinder piston, and control the force applied by the cylinder by controlling the air pressure in the air source;
[0025] Step 3: Install the sensor: Install the sensor or load cell on the piston of the cylinder to measure the force applied by the cylinder;
[0026] Step 4: Torque calculation: The torque is obtained by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section.
[0027] In step one, you need to select double-acting cylinders because they are able to apply force in two directions and can control the speed and position of the cylinder; and you need to select appropriate cylinder specifications, including cylinder diameter, stroke and load capacity, diameter (D): usually select an appropriate diameter to provide the required force, stroke (S): the stroke should be long enough to provide the required displacement and consider the space for sensor installation, maximum working pressure (P): ensure that the maximum working pressure of the cylinder is not lower than the working pressure required by the system; ensure that the pressure provided by the air source is stable and sufficient to meet the operating requirements of the cylinder; cylinder connection: connect the other port of the cylinder to the device that needs to measure torque, and ensure that the force applied by the cylinder can be transmitted to the device being measured.
[0028] In step two, install an air pressure regulating valve on the air supply pipeline to adjust the pressure of the air source, thereby controlling the force applied by the cylinder. Connect the air supply pipeline to the air inlet of the cylinder through the cylinder body of the cylinder, and ensure that the connection is tight to prevent gas leakage. Control the pressure of the air source by adjusting the air pressure regulating valve. Increasing the air pressure will increase the force applied by the cylinder, while reducing the air pressure will reduce the force applied by the cylinder. Adjust the air pressure as needed to achieve the desired torque application effect. Monitor the output data of the air pressure sensor to ensure that the air pressure regulation and the operation of the cylinder are as expected and can achieve the desired torque application effect.
[0029] The sensor in step three is a variable area capacitive sensor. When determining the installation position of the sensor, it is necessary to consider the motion trajectory of the piston and the structure of the cylinder to ensure that the sensor can accurately measure the applied force and will not be damaged or interfered with. The calibration process requires the use of a known load and recording the output value of the sensor. The sensor is calibrated using a standard load or pressure gauge, and then the sensor parameters are adjusted according to the calibration curve. During the testing and verification phase, different loads are used to test the response of the sensor and verify the stability and accuracy of its output. Different forces are applied to simulate different torques, and the output values of the sensor are recorded for analysis and verification.
[0030] The capacitive torque sensor is a flexible sheet consisting of a moving electrode plate and a static electrode plate. The static electrode plate consists of two electrode plates A and B with the same structure and size. The moving electrode plate consists of multiple groups of parallel electrodes connected at both ends. These electrodes have the same structural size and are arranged equidistantly, and the spacing between them is equal to the width of the electrode.
[0031] The calculation method in step 4 is that when the rotating shaft is subjected to a torsional load, it will cause deformation of the shaft, which is manifested as relative torsion of two sections at different positions on the shaft, forming a torsion angle. The more obvious the torsional deformation, the larger the torsion angle, L (m) is the length of the shaft, R (m) is the radius of the shaft, T (Nm) is the torque, γ is the shear strain, and φ (rad) is the relative torsion angle of the two sections. For the two ends of the rotating shaft with a distance of dx (m), the relative torsion angle dφ (rad), the shear elastic modulus G (Pa), the polar moment of inertia Ip (m4) and the torque T satisfy the following relationship: For equal radius axes, it can be obtained by integrating along the axis: Therefore, the torque can be obtained by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section.
[0032] Specifically, the working principle of the capacitive sensor can be explained by the flat plate capacitor shown in the figure. When the edge effect is ignored, its capacitance C is In the formula, ε is the dielectric constant between the capacitor plates; S is the relative coverage area of the plates; d is the distance between the plates; rε is the relative dielectric constant; 0ε is the dielectric constant of vacuum; According to the formula, when one of the dielectric constant, relative area and relative distance changes, its capacitance value will also change. The changing dielectric constant can be used to measure changes in concentration and material, while changes in area and distance can be used to measure changes in displacement and angular displacement. In addition, changes in physical quantities such as acceleration and pressure can also be indirectly measured. The edge effect of capacitive sensors is an important factor affecting their practical applications. Generally speaking, the influence of edge electric fields can be weakened by structural design. One electrode of the capacitor is grounded, and the other active electrode is completely surrounded by additional conductive electrodes in the same plane and isolated from the active electrode. Assuming that there is zero gap between the guard electrode and the two electrodes and the width is infinite, the effective field of the electric field over the entire area is uniform. However, since the guard electrode has a finite size and the gap width is not zero, an error will occur, which depends on the size of the guard electrode and the gap width: Where d is the plate distance; x is the width of the guard electrode; s is the gap width between the guard electrode and the active electrode; according to the empirical rule, x / d and d / s are equal to 5, and these errors are less than 0.1%;
[0033] The capacitive torque sensor is a flexible sheet consisting of a moving electrode plate and a static electrode plate. The static electrode plate consists of two electrode plates A and B with the same structure and size. The moving electrode plate consists of multiple groups of parallel electrodes connected at both ends. These electrodes have the same structural size and are arranged equidistantly, and their spacing is equal to the width of the electrode. Since the static electrode plate is installed outside the moving electrode plate, the width of the moving electrode plate and the static electrode plate are the same, but the length of the static electrode plate is slightly longer than that of the moving electrode plate, and the number of electrodes on the static electrode plate is twice the number of electrodes on the moving electrode plate; the moving electrode plate is installed on the surface of the rotating shaft, and the static electrode plate is installed on the fixed part outside the shaft, and the two form a capacitor relative to each other. When the shaft rotates, the electrode coverage area on the moving electrode plate and the static electrode plate shows a periodic change feature. Therefore, in the absence of external excitation, the electrode plates A and B of the moving electrode plate and the multiple groups of electrodes of the static electrode plate form a pair of differential capacitors. The capacitive sensor is equivalent to several parallel flat plate capacitors. When the influence of the edge effect is ignored, the capacitance value is: C = nε rε0sd, where n is the number of capacitive sensor strips; s is the effective overlapping area of two capacitive strips; d is the distance between the two plates; 0ε is the dielectric constant of a vacuum; the dielectric constant of air is rε=1; when the torque of the rotating shaft changes, a torsion angle will be generated, and the relative positions of the moving plates of the sensors at different positions on the shaft will change, causing a time difference in the capacitance change of the sensor. By measuring this difference, torque measurement is achieved. Compared with ordinary capacitive sensors, its advantage is that the electrodes on the moving and static plates can be subdivided to achieve higher accuracy, and the average effect of multiple electrodes can effectively reduce the measurement error caused by shaft vibration. According to the theory of material mechanics, when a rotating shaft is subjected to a torsional load, it will cause deformation of the shaft, which is manifested as relative torsion of two sections at different positions on the shaft, forming a torsion angle. The more obvious the torsional deformation, the larger the torsion angle, such as Figure 2-3 As shown. In this figure, L (m) is the length of the shaft, R (m) is the radius of the shaft, T (Nm) is the torque, γ is the shear strain, and φ (rad) is the relative torsion angle of the two sections. For the two ends of the rotating shaft with a distance of dx (m), the relative torsion angle dφ (rad), the shear elastic modulus G (Pa), the polar moment of inertia I p (m4) and the torque T satisfy the following relationship:
[0034] For axes of constant radius, this can be obtained by integrating along the axis:
[0035] Therefore, the torque can be obtained by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section. When there is no torque on the shaft, the output signals of capacitive sensors 1 and 2 are the same. When the shaft is subjected to torque, due to the torsion angle difference between the shaft sections where capacitive sensors 1 and 2 are located, the moving plates of the two sensors produce relative angular displacement, which is manifested as a phase difference in the sensor output signals. By measuring the torsion angle difference between the two cross sections of the shaft, the torque of the shaft is calculated using the above formula.
[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A torque measurement method based on cylinder drive, characterized in that: The specific steps include: Step 1: Cylinder system design: Design a cylinder system with one port connected to the air source and the other port connected to the device that needs to measure torque; Step 2: Cylinder control: Control the air source to control the movement of the cylinder piston, and control the force applied by the cylinder by controlling the air pressure in the air source; Step 3: Install the sensor: Install the sensor or load cell on the piston of the cylinder to measure the force applied by the cylinder; Step 4: Torque calculation: The torque is obtained by measuring the relative torsion angle between any two sections. The relative torsion angle can be regarded as the angular displacement of one section relative to another section.
2. A method for measuring torque based on cylinder drive according to claim 1, characterized in that: In step 1, double-acting cylinders need to be selected because they can apply force in two directions and can control the speed and position of the cylinder; and appropriate cylinder specifications need to be selected, including cylinder diameter, stroke and load capacity, diameter (D): usually select an appropriate diameter to provide the required force, stroke (S): the stroke should be long enough to provide the required displacement and take into account the space for sensor installation, maximum working pressure (P): ensure that the maximum working pressure of the cylinder is not lower than the working pressure required by the system; ensure that the pressure provided by the air source is stable and sufficient to meet the operating requirements of the cylinder; cylinder connection: connect the other port of the cylinder to the device that needs to measure torque to ensure that the force applied by the cylinder can be transmitted to the device being measured.
3. The method for measuring torque based on cylinder drive according to claim 1, characterized in that: In the step 2, an air pressure regulating valve is installed on the air supply pipeline to adjust the pressure of the air source, thereby controlling the force applied by the cylinder. The air supply pipeline is connected to the air inlet of the cylinder through the cylinder body of the cylinder, and the connection is ensured to be tight to prevent gas leakage. The pressure of the air source is controlled by adjusting the air pressure regulating valve. Increasing the air pressure will increase the force applied by the cylinder, while reducing the air pressure will reduce the force applied by the cylinder. The air pressure is adjusted as needed to achieve the desired torque application effect, and the output data of the air pressure sensor is monitored to ensure that the air pressure regulation and the operation of the cylinder are as expected and can achieve the desired torque application effect.
4. The method for measuring torque based on cylinder drive according to claim 1, characterized in that: The sensor in step three is a variable area capacitive sensor. When determining the installation position of the sensor, it is necessary to consider the motion trajectory of the piston and the structure of the cylinder to ensure that the sensor can accurately measure the applied force and will not be damaged or interfered with. The calibration process requires the use of a known load and recording the output value of the sensor. The sensor is calibrated using a standard load or pressure gauge, and then the parameters of the sensor are adjusted according to the calibration curve. During the testing and verification stage, different loads are used to test the response of the sensor and verify the stability and accuracy of its output. Different forces are applied to simulate different torques, and the output value of the sensor is recorded for analysis and verification.
5. The method for measuring torque based on cylinder drive according to claim 4, characterized in that: The capacitive torque sensor is a flexible sheet consisting of a moving electrode plate and a static electrode plate. The static electrode plate is composed of two electrode plates A and B with the same structure and size. The moving electrode plate is composed of multiple groups of parallel electrodes connected at both ends. These electrodes have the same structural size and are arranged equidistantly, and the spacing between them is equal to the width of the electrode.
6. The method for measuring torque based on cylinder drive according to claim 1, characterized in that: The calculation method in step 4 is that when the rotating shaft is subjected to a torsional load, it will cause deformation of the shaft, which is manifested as relative torsion of two sections at different positions on the shaft, forming a torsion angle. The more obvious the torsional deformation, the larger the torsion angle. L (m) is the length of the shaft, R (m) is the radius of the shaft, T (Nm) is the torque, γ is the shear strain, φ (rad) is the relative torsion angle of the two sections, and for the two ends of the rotating shaft with a distance of dx (m), the relative torsion angle dφ (rad), the shear elastic modulus G (Pa), the polar moment of inertia Ip (m4) and the torque T satisfy the following relationship. For equal radius axes, it can be obtained by integrating along the axis: Therefore, the torque can be obtained by measuring the relative torsion angle between any two sections, which can be regarded as the angular displacement of one section relative to the other.