A method and system for measuring the torque of a brushed torque motor

Abstract

The present invention relates to the technical field of measurement methods, and discloses a torque measurement method and system for a brushed torque motor. In this method, the rotor is installed on the rotating shaft, and then the stator is installed on the base. A brush holder is installed on the stator, and brushes that contact the surface of the rotor are provided on the brush holder. A dynamometer is used to apply tensile forces in the positive and negative directions along the plumb line until the rotating shaft rotates. The stator is disassembled and replaced with a tooling bracket, and then the dynamometer is used to apply tensile force until the rotating shaft rotates. According to the principle of torque balance, the mechanical equilibrium equations at different rotation instants are respectively listed, so as to calculate the excitation torque and the eccentric force torque respectively. The present invention directly uses the drive shaft system structure for measurement, simplifies the measurement device, greatly reduces the processing difficulty and processing cost, can reliably obtain the excitation torque and the eccentric force torque, has a simple calculation process, improves the measurement accuracy, and is also convenient for operation and observation.

Description

Technical Field

[0001] The present invention relates to the technical field of torque measurement, and more specifically, to a torque measurement method and system for a brushed torque motor. Background Art

[0002] After the permanent magnet of the split-type brushed torque motor is excited, an exciting torque is generated, which has a great influence on the torque ripple and starting voltage of the split-type brushed torque motor and is an important index for the inspection of the split-type brushed torque motor. There are mainly two existing publicly disclosed methods for measuring the exciting torque. One is to directly measure the force by hanging weights and then multiply it by the force arm to calculate the torque. The other is to multiply the starting current by the torque sensitivity to calculate the torque. Both methods require a dedicated rotating shaft system to be built. The stator and rotor of the split-type brushed torque motor are respectively installed on the stator and rotor of the shaft system, and then multiple groups of brushes are installed on the stator through a brush holder. The structure is complex, and the processing and assembly requirements are high.

[0003] Both of the above two methods ignore the frictional torque of the bearings, the frictional torque of the brushes, and the eccentric torque of the shaft system in the rotating shaft system, resulting in large measurement errors and low accuracy. At the same time, the first method requires multiple operations of adding and subtracting weights, which is cumbersome. The second method also requires the split-type brushed torque motor to be energized and kept in a stalled state during measurement, and the torque sensitivity is calculated after measuring the stall torque and stall current. Affected by the maximum stall time of the split-type brushed torque motor, the measurement time of the exciting torque must be strictly limited and cannot exceed the maximum stall time of the split-type brushed torque motor. Special power supplies and measuring instruments need to be additionally configured, with a large investment and high cost.

[0004] In the existing drive shaft system of the brushed torque motor, the load, the rotating shaft, and the rotor of the brushed torque motor can perform rotational movements. Due to the influence of processing accuracy, spatial dimensions, weight limitations, etc., generally, the centers of mass of the load, the rotating shaft, and the rotor of the motor do not coincide with the center of rotation of the rotating shaft. It is necessary to measure and control the eccentric torque of the drive shaft system after assembly, and perform structural balancing if necessary according to the measurement results. There are mainly two methods for measuring the eccentric torque of the drive shaft system. One is to separately measure the mass and center of mass of the rotating part of the drive shaft system and directly calculate the gravity and then multiply it by the gravity arm to calculate the eccentric torque. The other is to use the piezoelectric effect principle of strain gauges, paste strain gauges on the measured part, and measure the torque through a single-chip full-bridge or group-bridge method of the strain gauges to process the circuit.

[0005] The first method mentioned above requires measurement before the assembly of the drive shaft system, or after disassembling the assembled drive shaft system, and a special quality characteristic measuring instrument is needed for measurement. When measuring, the rotating part of the drive shaft system needs to be installed on the moving shaft of the quality characteristic measuring instrument to make a high-speed rotating motion. The structure is complex, the investment is large, and the cost is high. The formal assembly of the drive shaft system can only be carried out after the measurement, and the eccentric error caused by the installation error cannot be avoided. The principle of the second method is complex and the operation is cumbersome. Strain gauges need to be pasted on the measured part, and the requirements for pasting the strain gauges are very high. Improper pasting will cause problems such as zero drift and creep. After the strain gauges are pasted, it is also necessary to check for air bubbles, warping and delamination, and measure for short circuits, open circuits and resistance mutation phenomena. Summary of the Invention

[0006] The object of the present invention is to provide a torque measurement method and system for a brushed torque motor, which can reliably obtain the excitation torque and the eccentric torque, the calculation process is simple, and the measurement accuracy is improved, aiming at the technical problems existing in the prior art.

[0007] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a torque measurement method for a brushed torque motor. The specific steps of the measurement method are as follows:

[0009] Construct a drive shaft system, including a base and a rotating shaft. The rotating shaft is arranged on the base and perpendicular to the plumb line, and the rotating shaft is connected to a load.

[0010] Install a brushed torque motor, including a stator, a rotor, a brush holder and a brush. The rotor is sleeved on the rotating shaft, and the stator is arranged on the base and located on the outer surface of the rotor. The brush holder is arranged between the stator and the rotor and connected to the stator. The brush is arranged on the brush holder, and the inner surface contacts the outer surface of the rotor. One end of a pulling rope is pasted on the outer end face of the rotor, and the other end of the pulling rope is connected to the hook of a dynamometer.

[0011] Slowly apply a pulling force to the dynamometer along the plumb line direction from zero until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F1.

[0012] Rotate the rotating shaft again to make the rotor return to the initial position, and slowly apply a pulling force to the dynamometer along the opposite direction of the plumb line from zero until the rotor just starts to rotate relative to the stator, and record the reading of the dynamometer at this time as F2.

[0013] According to the obtained forces F1 and F2, calculate that the eccentric torque of the drive shaft system of the brushed torque motor is 0.5×(F1 - F2)×L1, where the distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1.

[0014] Remove the stator of the motor and replace it with a tooling bracket. The brush holder is installed on the tooling bracket. Rotate the rotating shaft again to restore the rotor to its initial position.

[0015] Apply a pulling force slowly along the plumb line direction from zero with a dynamometer until the rotor just starts to rotate relative to the tooling bracket, and record the reading of the dynamometer at this time as F3.

[0016] Based on the obtained forces F1 and F3, calculate the excitation torque of the brushed torque motor as (F1 - F3) × L1.

[0017] Furthermore, at the initial position, alignment marking lines are respectively set on the outer end faces of the stator and the rotor, and on the tooling bracket.

[0018] Furthermore, calculating the eccentric moment of the drive shaft system of the brushed torque motor specifically includes:

[0019] Based on F1, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows:

[0020] F1×L1 - G×L - M1 - M2 - M3 = 0 (1)

[0021] Based on F2, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the stator is as follows:

[0022] F2×L1 + G×L - M1 - M2 - M3 = 0 (2)

[0023] Wherein, G is the gravity of the combined body of the rotating shaft, the load, and the rotor, L is the gravity arm of the combined body, M1 is the frictional torque of the bearing in the drive shaft system, M2 is the excitation torque of the brushed torque motor, and M3 is the frictional torque of the brush.

[0024] Based on formula (1) and formula (2), calculate the eccentric moment of the drive shaft system of the brushed torque motor as: G×L = 0.5×(F1 - F2)×L1.

[0025] Furthermore, calculating the excitation torque of the brushed torque motor specifically includes:

[0026] Based on F3, the mechanical equilibrium equation at the moment when the rotor just starts to rotate relative to the tooling bracket is as follows:

[0027] F3×L1 - G×L - M1 - M3 = 0 (3)

[0028] Based on formula (1) and formula (3), calculate the excitation torque of the brushed torque motor as: M2 = (F1 - F3)×L1.

[0029] Further, the dynamometer is an electronic dynamometer, and the increment of the pulling force applied each time is the minimum unit indication value of the dynamometer.

[0030] A system for a torque measurement method based on a brushed torque motor, characterized in that: the measurement system includes:

[0031] Shafting construction module: used to construct a drive shafting, including a base and a rotating shaft, the rotating shaft is arranged on the base and perpendicular to the plumb line, and the rotating shaft is connected to a load;

[0032] Motor installation module: used to install a brushed torque motor, including a stator, a rotor, a brush holder and brushes, the rotor is sleeved on the rotating shaft, the stator is arranged on the base and located on the outer surface of the rotor; the brush holder is arranged between the stator and the rotor and connected to the stator; the brushes are arranged on the brush holder, and the inner surface contacts the outer surface of the rotor; one end of a pull rope is pasted on the outer end face of the rotor, and the other end of the pull rope is connected to the hook of the dynamometer;

[0033] First operation module: used to slowly apply a pulling force to the dynamometer along the plumb line direction starting from zero until the rotor just rotates relative to the stator, and record the indication value of the dynamometer at this time as F1;

[0034] Second operation module: used to rotate the rotating shaft again to make the rotor return to the initial position, and slowly apply a pulling force to the dynamometer along the opposite direction of the plumb line starting from zero until the rotor just rotates relative to the stator, and record the indication value of the dynamometer at this time as F2;

[0035] Eccentric torque calculation module: used to calculate the eccentric torque of the drive shafting of the brushed torque motor as 0.5×(F1 - F2)×L1 according to the obtained force F1 and force F2, where the distance between the bonding point of the pull rope and the center line of the rotating shaft is L1.

[0036] Further, the measurement system further includes:

[0037] Disassembly and replacement module: used to remove the stator of the motor and replace it with a tooling bracket, the brush holder is installed on the tooling bracket, and rotate the rotating shaft again to make the rotor return to the initial position;

[0038] Third operation module: used to slowly apply a pulling force to the dynamometer along the plumb line direction starting from zero until the rotor just rotates relative to the tooling bracket, and record the indication value of the dynamometer at this time as F3;

[0039] Excitation torque calculation module: used to calculate the excitation torque of the brushed torque motor as (F1 - F3)×L1 according to the obtained force F1 and force F3.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) The measurement method of the present invention makes full use of the existing drive shaft system structure, without the need to specially build a measurement rotary shaft system, simplifies the measurement device, and greatly reduces the processing difficulty and cost. Considering the frictional torque of the bearings and the frictional torque of the brushes in the drive shaft system, through three force measurements, under the coupling action of these four torques, namely the frictional torque of the bearings, the frictional torque of the brushes, the eccentric torque of the shaft system, and the exciting torque of the motor, the measurement of the exciting torque of the motor is realized. At the same time, the on-line measurement and discrimination of the eccentric torque during the assembly process of the drive shaft system are also realized. The calculation process is simple, and the measurement accuracy is improved.

[0042] (2) Alignment marking lines are set on the outer end faces of the stator and rotor and on the tooling bracket in the present invention, which is convenient for observing the moment when the rotor rotates relative to the stator and the tooling bracket, and ensures the accuracy and reliability of the readings of the dynamometer obtained.

[0043] (3) Through three force measurements and applying the principle of torque balance, the present invention realizes the measurement of the exciting torque of the motor and the eccentric torque of the drive shaft system without measuring the frictional torque of the bearings and the frictional torque of the brushes. It is simple, reliable and easy to implement.

[0044] (4) The present invention uses an electronic dynamometer to measure force, without the need to operate on weights, nor the need for strain gauges and processing circuits. The operation and observation are simple and convenient, and the measurement is also reliable.

[0045] (5) The measurement system of the present invention directly uses the drive shaft system for measurement. The rotor is installed on the rotating shaft and then the stator is installed on the base. The dynamometer is used to apply tensile force in the positive and negative directions along the plumb line until the rotating shaft rotates. Then the stator is disassembled and replaced with a tooling bracket, and the dynamometer is used to apply tensile force until the rotating shaft rotates. According to the principle of torque balance, the mechanical equilibrium equations at different rotation moments are listed respectively, so as to obtain the exciting torque and the eccentric torque respectively. The measurement accuracy is high, the calculation process is simple, and it is also convenient for operation and observation. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the solutions in the present invention, the following will give a brief introduction to the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings. Among them:

[0047] Figure 1 is the flowchart of the torque measurement method of the brush torque motor of the present invention.

[0048] Figure 2 is the schematic diagram of the first measurement in the state of the drive shaft system of the present invention and the installation of the motor stator and rotor.

[0049] Figure 3 This is a schematic diagram of the second measurement of the present invention.

[0050] Figure 4 This is a schematic diagram of the measurement in the drive shaft system of the present invention when the stator is replaced by a tooling bracket.

[0051] Figure 5 This is a schematic diagram of the principle of the torque measurement system of the brushed torque motor of the present invention.

[0052] Wherein, 1 - base, 2 - rotating shaft, 3 - stator, 4 - rotor, 5 - centroid of the combined body of the rotating shaft, load and rotor, 6 - center line of the rotating shaft, 7 - pulling rope, 8 - bonding point of the pulling rope, 9 - dynamometer, 10 - brush holder, 11 - brush, 12 - tooling bracket. Specific embodiments

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs; the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms such as "length", "width", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or position based on the orientation or position shown in the drawings, and are only for convenience of description and cannot be construed as a limitation to the technical solution of the present invention.

[0054] The terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention and the above description of the drawings are intended to cover non-exclusive inclusion; the terms "first", "second", etc. in the specification and claims of the present invention or the above description of the drawings are used to distinguish different objects and not to describe a specific order. In the specification and claims of the present invention and the above description of the drawings, when an element is referred to as being "fixed to" or "mounted on" or "disposed on" or "connected to" another element, it can be directly or indirectly located on the other element. For example, when an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.

[0055] In addition, the mention of "embodiment" herein means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0056] Refer to Figure 1As shown in the figure, the present invention provides a torque measurement method for a brushed torque motor. The specific steps of this measurement method are as follows:

[0057] Step S1: As Figure 2 shown in the figure, a driving shaft system is constructed. The driving shaft system includes a base 1 and a rotating shaft 2. The rotating shaft 2 is arranged on the base 1 and is perpendicular to the plumb line. The rotating shaft 2 is connected to a load.

[0058] Step S2: Install a brushed torque motor. The brushed torque motor includes a stator 3, a rotor 4, a brush holder 10 and multiple groups of brushes 11. The rotor 4 is sleeved on the rotating shaft 2. The stator 3 is arranged on the base 1 and is located on the outer surface of the rotor 4. The brush holder 10 is arranged between the stator 3 and the rotor 4 and is connected to the stator 3. Multiple groups of brushes 11 are arranged on the brush holder 10. The inner surface of the brush 11 contacts the outer surface of the rotor 4. One end of a pulling rope 7 is pasted on the outer end face of the rotor 2, and the other end of the pulling rope 7 is connected to the hook of a dynamometer 9.

[0059] Specifically, the rotating shaft 2 is connected to the base 1 through a bearing to ensure reliable connection. The rotating shaft 2, the rotor 4 and the load can perform a rotary motion. The number of the brushes 11 can be increased or decreased according to actual needs.

[0060] Step S3: Slowly apply a pulling force to the dynamometer 9 along the plumb line direction (i.e., vertically upward in the figure) starting from zero until the rotor 4 just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time, denoted as F1.

[0061] In this step, alignment marking lines are provided on the outer end faces of the stator 3 and the rotor 4. During the process of applying the pulling force, observe the marking lines on the outer end faces of the rotor 4 and the stator 3. When the alignment marking lines of the two just do not align, it is determined that the rotor 4 just rotates relative to the stator 3. At this time, the reading of the dynamometer 9 corresponding to this is F1, which is convenient for observing the moment of rotation of the rotor 4.

[0062] Step S4: As Figure 3 shown in the figure, rotate the rotating shaft 2 again to make the rotor 4 return to the initial position, and slowly apply a pulling force to the dynamometer 9 along the opposite direction of step S3 (i.e., vertically downward in the figure) starting from zero until the rotor 4 of the motor just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time, denoted as F2.

[0063] In this step, rotate the rotating shaft 2 to make the marking line on the outer end face of the rotor 4 return to the position in step S3. During the process of applying the pulling force, also observe the marking lines on the outer end faces of the rotor 4 and the stator 3 of the motor to determine that the rotor 4 just rotates relative to the stator 3.

[0064] Step S5: According to the obtained forces F1 and F2, calculate the eccentric moment of the drive shaft system of the brushed torque motor to be 0.5×(F1 - F2)×L1, where the distance between the pulling rope bonding point 8 on the rotor 2 and the axis center line 6 of the rotating shaft is L1.

[0065] In this step S5, calculating the eccentric moment of the drive shaft system of the brushed torque motor specifically includes:

[0066] According to the moment balance principle, based on F1, the mechanical balance equation when the rotor 4 of the motor just starts to rotate relative to the stator 3 is as follows:

[0067] F1×L1 - G×L - M1 - M2 - M3 = 0 (1)

[0068] Similarly, according to the moment balance principle, based on F2, the mechanical balance equation when the rotor 4 of the motor just starts to rotate relative to the stator 3 is as follows:

[0069] F2×L1 + G×L - M1 - M2 - M3 = 0 (2)

[0070] Wherein, G is the gravity of the combined body of the rotating shaft 2, the load, and the rotor 4, L is the gravity arm of the combined body of the rotating shaft 2, the load, and the rotor 4, M1 is the frictional torque of the bearing in the drive shaft system, M2 is the exciting torque of the split - type brushed torque motor, and M3 is the frictional torque of the brush;

[0071] According to formula (1) and formula (2), calculate the eccentric moment of the drive shaft system of the brushed torque motor to be:

[0072] G×L = 0.5×(F1 - F2)×L1.

[0073] Step S6: As Figure 4 shown, remove the stator 3 of the motor and replace it with the tooling bracket 12. The brush holder 10 is installed on the tooling bracket 12, and the inner surface of the brush 11 also contacts the surface of the rotor 4. Rotate the rotating shaft 2 again to make the rotor 4 return to the initial position, that is, the marking line on the outer end face of the rotor 4 returns to the position in step S2.

[0074] Step S7: Slowly apply a pulling force vertically along the plumb line direction (i.e., vertically upward in the figure) with the dynamometer 9 starting from zero. During the process of applying the pulling force, observe the outer end face of the rotor 4 and the tooling bracket 12 until the rotor 4 just starts to rotate relative to the tooling bracket 12, and record the reading of the dynamometer 9 at this time, denoted as F3.

[0075] In this step, the brush holder 10 is installed through the tooling bracket 12 to ensure the reliability of the motor operation. The tooling bracket 12 is also provided with alignment marking lines corresponding to the position of the rotor 4. At the initial position, the alignment marking lines of the two are aligned. When the alignment marking lines of the two are just misaligned, it means that the rotor 4 has just rotated relative to the tooling bracket 12, which is convenient for observation.

[0076] Step S8: According to the obtained forces F1 and F3, calculate that the excitation torque of the brushed torque motor is (F1 - F3) × L1.

[0077] In this step S8, calculating the excitation torque of the brushed torque motor specifically includes:

[0078] Based on the torque balance principle, according to the F3, the mechanical balance equation at the moment when the rotor 4 of the motor just rotates relative to the tooling bracket 12 is as follows:

[0079] F3 × L1 - G × L - M1 - M3 = 0 (3)

[0080] According to formula (1) and formula (3), calculate that the excitation torque of the brushed torque motor is: M2 = (F1 - F3) × L1.

[0081] Furthermore, the dynamometer 9 adopts an electronic dynamometer, and the increased value of the pulling force applied each time is the minimum unit indication value of the dynamometer, which can avoid inaccurate measurement results caused by excessive force and improve the measurement accuracy.

[0082] Refer to Figure 5 As shown, the present invention also provides a torque measurement system for a brushed torque motor, including:

[0083] Shafting construction module: used to construct a drive shafting. The drive shafting includes a base 1 and a rotating shaft 2. The rotating shaft 2 is arranged on the base 1 and is perpendicular to the plumb line. The rotating shaft 2 is connected to a load.

[0084] Motor installation module: used to install a brushed torque motor. The brushed torque motor includes a stator 3, a rotor 4, a brush holder 10 and multiple groups of brushes 11. The rotor 4 is sleeved on the rotating shaft 2. The stator 3 is arranged on the base 1 and is located on the outer surface of the rotor 4. The brush holder 10 is arranged between the stator 3 and the rotor 4 and is connected to the stator 3. Multiple groups of brushes 11 are arranged on the brush holder 10, and the inner surface of the brushes 11 contacts the outer surface of the rotor 4. One end of a pulling rope 7 is pasted on the outer end face of the rotor 4, and the other end of the pulling rope 7 is connected to the hook of the dynamometer 9. The distance between the pulling rope bonding point and the center line of the rotating shaft is L1.

[0085] The first operation module: It is used to slowly apply a pulling force to the dynamometer 9 along the plumb line direction starting from zero until the rotor 4 just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time as F1.

[0086] The second operation module: It is used to rotate the rotating shaft 2 again to make the rotor 4 return to the initial position, and slowly apply a pulling force to the dynamometer 9 along the opposite direction of the plumb line starting from zero until the rotor 4 of the motor just rotates relative to the stator 3, and record the reading of the dynamometer 9 at this time as F2.

[0087] The eccentric moment calculation module: It is used to calculate the eccentric moment of the drive shaft system of the brushed torque motor as 0.5×(F1 - F2)×L1 according to the obtained force F1 and force F2.

[0088] The disassembly and replacement module: It is used to remove the stator 3 of the motor and replace it with the tooling bracket 12, the brush holder 10 is installed on the tooling bracket 12, and rotate the rotating shaft 2 again to make the rotor 4 return to the initial position.

[0089] The third operation module: It is used to slowly apply a pulling force to the dynamometer 9 along the plumb line direction starting from zero until the rotor 4 just rotates relative to the tooling bracket 12, and record the reading of the dynamometer 9 at this time as F3.

[0090] The exciting torque calculation module: It is used to calculate the exciting torque of the brushed torque motor as (F1 - F3)×L1 according to the obtained force F1 and force F3.

[0091] Specifically, the system provided by the embodiment of the present invention is specifically used to execute the above method embodiment, and the embodiment of the present invention will not be elaborated here again.

[0092] The torque measurement method and system of the brushed torque motor provided by the present invention make full use of the existing drive shaft system structure, without disassembling the drive shaft system. When measuring, the drive shaft system has been formally assembled, effectively avoiding the eccentric error caused by the installation error, and considering the friction torque of the bearings and the friction torque of the brushes in the drive shaft system. By applying the torque balance principle, while not measuring the sum of the friction torque of the bearings and the friction torque of the brushes, the measurement of the exciting torque of the motor and the eccentric moment of the drive shaft system is realized, which is simple, reliable and easy to implement. In addition, when measuring the exciting torque of the present invention, there is no need to energize and block the rotation of the split-type brushed torque motor, the measurement time is not limited by the maximum blocking time, there is no need to configure additional dedicated power supplies and measuring instruments, and the debugging method is simple and practical.

[0093] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A torque measurement method for a brushed torque motor, characterized in that: The specific steps of this measurement method are as follows: Construct a drive shaft system, including a base and a rotating shaft. The rotating shaft is arranged on the base and perpendicular to the plumb line, and the rotating shaft is connected to a load. Install a brushed torque motor, including a stator, a rotor, a brush holder and brushes. The rotor is sleeved on the rotating shaft, and the stator is arranged on the base and located on the outer surface of the rotor. The brush holder is arranged between the stator and the rotor and connected to the stator. The brushes are arranged on the brush holder, and the inner surface contacts the outer surface of the rotor. One end of a pulling rope is pasted on the outer end face of the rotor, and the other end of the pulling rope is connected to the hook of a dynamometer. Apply a pulling force slowly from zero along the plumb line direction to the dynamometer until the rotor just rotates relative to the stator, and record the reading of the dynamometer at this time as F1. Rotate the rotating shaft again to make the rotor return to the initial position, and apply a pulling force slowly from zero along the opposite direction of the plumb line to the dynamometer until the rotor just rotates relative to the stator, and record the reading of the dynamometer at this time as F2. According to the obtained forces F1 and F2, calculate the eccentric moment of the drive shaft system of the brushed torque motor as 0.5×(F1 - F2)×L1, where the distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1. Remove the stator of the motor and replace it with a tooling bracket. The brush holder is installed on the tooling bracket, and rotate the rotating shaft again to make the rotor return to the initial position. Apply a pulling force slowly from zero along the plumb line direction to the dynamometer until the rotor just rotates relative to the tooling bracket, and record the reading of the dynamometer at this time as F3. According to the obtained forces F1 and F3, calculate the excitation moment of the brushed torque motor as (F1 - F3)×L1.

2. The torque measurement method for a brushed torque motor according to claim 1, characterized in that: At the initial position, alignment marking lines are respectively set on the outer end faces of the stator and the rotor, and on the tooling bracket.

3. The torque measurement method for a brushed torque motor according to claim 1 or 2, characterized in that: The calculation of the eccentric moment of the drive shaft system of the brushed torque motor specifically includes: According to F1, the mechanical equilibrium equation at the moment when the rotor just rotates relative to the stator is as follows: F1×L1 - G×L - M1 - M2 - M3 = 0 (1) According to F2, the mechanical equilibrium equation at the moment when the rotor just rotates relative to the stator is as follows: F2×L1 + G×L - M1 - M2 - M3 = 0 (2) Wherein, G is the gravity of the combined body of the rotating shaft, the load and the rotor, L is the gravity arm of the combined body, M1 is the friction moment of the bearing in the drive shaft system, M2 is the excitation moment of the brushed torque motor, and M3 is the friction moment of the brushes. According to formula (1) and formula (2), calculate the eccentric moment of the drive shaft system of the brushed torque motor as: G×L = 0.5×(F1 - F2)×L1.

4. The torque measurement method for a brushed torque motor according to claim 3, characterized in that: The calculation of the excitation moment of the brushed torque motor specifically includes: According to F3, the mechanical equilibrium equation at the moment when the rotor just rotates relative to the tooling bracket is as follows: F3×L1 - G×L - M1 - M3 = 0 (3) According to formula (1) and formula (3), calculate the excitation moment of the brushed torque motor as: M2 = (F1 - F3)×L1.

5. The torque measurement method for a brushed torque motor according to claim 1 or 4, characterized in that: The dynamometer adopts an electronic dynamometer, and the increment of the pulling force applied each time is the minimum unit reading value of the dynamometer.

6. A system based on the torque measurement method for a brushed torque motor according to any one of claims 1 to 5, characterized in that: This measurement system includes: Shafting construction module: Used to construct a drive shafting, including a base and a rotating shaft. The rotating shaft is arranged on the base and perpendicular to the plumb line, and the rotating shaft is connected to a load. Motor mounting module: Used to mount a brushed torque motor, including a stator, a rotor, a brush holder and brushes. The rotor is sleeved on the rotating shaft, and the stator is arranged on the base and located on the outer surface of the rotor. The brush holder is arranged between the stator and the rotor and connected to the stator. The brushes are arranged on the brush holder, and the inner surface contacts the outer surface of the rotor. One end of a pulling rope is pasted on the outer end face of the rotor, and the other end of the pulling rope is connected to the hook of a dynamometer. First operation module: Used to slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just rotates relative to the stator, and record the reading of the dynamometer at this time as F1. Second operation module: Used to re-rotate the rotating shaft to make the rotor return to the initial position, and slowly apply a pulling force along the opposite direction of the plumb line from zero to the dynamometer until the rotor just rotates relative to the stator, and record the reading of the dynamometer at this time as F2. Eccentric moment calculation module: Used to calculate the eccentric moment of the drive shafting of the brushed torque motor as 0.5×(F1 - F2)×L1 according to the obtained force F1 and force F2, where the distance between the bonding point of the pulling rope and the center line of the rotating shaft is L1. The measurement system further includes: Disassembly and replacement module: Used to remove the stator of the motor and replace it with a tooling bracket. The brush holder is installed on the tooling bracket, and the rotating shaft is re-rotated to make the rotor return to the initial position. Third operation module: Used to slowly apply a pulling force along the plumb line direction from zero to the dynamometer until the rotor just rotates relative to the tooling bracket, and record the reading of the dynamometer at this time as F3. Excitation torque calculation module: Used to calculate the excitation torque of the brushed torque motor as (F1 - F3)×L1 according to the obtained force F1 and force F3.

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