Method for evaluating micro-motion wear life of conductive plastic potentiometer

Abstract

The application provides a method for evaluating the micro-motion wear life of a conductive plastic potentiometer, which comprises the following steps: S1, obtaining a brush claw tip vibration displacement spectrum according to a random vibration load spectrum of a potentiometer shell; S2, obtaining a brush claw tip circumferential flutter displacement function; S3, counting the glancing point frequency of displacement points; S4, constructing a basic wear model of a conductive plastic film; S5, calculating the wear depth increment of each displacement point within a unit time; S6, determining a wear depth threshold; and S7, establishing a micro-motion wear life model. The application constructs a basic wear model of a conductive plastic film based on the brush claw tip vibration displacement statistics, and establishes a potentiometer micro-motion wear life model in combination with an actual vibration load spectrum of the potentiometer, which can be used for quantitatively evaluating and predicting the micro-motion wear life of the potentiometer under an actual working state, and provides technical support for the micro-motion wear life evaluation and research of the conductive plastic potentiometer.

Description

Technical Field

[0001] This invention relates to the field of product reliability, and in particular to a method for assessing the fretting wear life of conductive plastic potentiometers. Background Technology

[0002] Conductive plastic potentiometers are precision angular displacement sensors, widely used in industries such as smart manufacturing, aerospace, automotive, and home furnishings as an important component of feedback control systems. During use, potentiometers are inevitably affected by product or environmental vibrations, causing the brush tips to reciprocate repeatedly near a specific position on the conductive plastic resistive film (hereinafter referred to as the conductive plastic film). This results in localized fretting wear of the conductive plastic film, leading to unstable potentiometer output signals and even triggering sudden failures of the feedback control system, causing serious consequences. Therefore, accurately assessing the fretting wear life of conductive plastic potentiometers is crucial for improving their reliability and ensuring the safe and stable operation of the feedback control system in which they are located.

[0003] Existing potentiometer wear life assessments primarily rely on traditional testing methods, mainly falling into two categories: 1. Rotary load life test: This involves directly applying a rotational load to the potentiometer shaft to the specified quality level and assessing whether its life indicators meet the requirements. However, this type of test cannot simulate the localized rapid wear caused by high-frequency jitter of the potentiometer tip under vibration. Therefore, potentiometers that pass the test may still face the risk of sudden failure under vibration. 2. Flicker life test: During this test, the brush is oscillated at a low frequency and within a small range above a conductive plastic film several times until the specified quality level is reached. After the oscillation ends, the potentiometer's ability to continue normal operation is assessed. However, the oscillation frequency applied in this test is still much lower than the oscillation frequency of the brush tip in a vibration environment. Therefore, the flicker life cannot reflect the actual service life of the potentiometer under vibration. Furthermore, since both types of test methods are pass / fail assessments, they cannot quantitatively evaluate and predict the fretting wear life of potentiometers. Therefore, a new method for assessing the fretting wear life of conductive plastic potentiometers is needed to provide technical support for a more accurate quantitative assessment and research of the wear life of conductive plastic potentiometers. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a method for evaluating the fretting wear life of conductive plastic potentiometers. By constructing a potentiometer fretting wear life model, the fretting wear life of the potentiometer is evaluated, providing technical support for the quantitative evaluation and research of the wear life of conductive plastic potentiometers.

[0005] The method for evaluating the fretting wear life of conductive plastic potentiometers proposed in this invention comprises the following steps:

[0006] S1. Calculate the vibration displacement spectrum of the brush claw tip:

[0007] The potentiometer is taken as a random vibration system. The random vibration load spectrum of the potentiometer housing is input. The vibration displacement of the brush claw tip is solved by numerical method based on the vibration system response, and the vibration displacement spectrum A(ω) of the brush claw tip is output.

[0008] S2. Obtain the circumferential chatter displacement function of the brush claw tip:

[0009] The vibration displacement spectrum A(ω) of the brush claw tip is transformed from the frequency domain to the time domain to obtain the circumferential flutter displacement function p(t) of the brush claw tip;

[0010] S3, Statistical frequency of sweep points at displacement points:

[0011] Based on the displacement function p(t) in step S2, determine the displacement range of the displacement function p(t) [p min p max ], and for the displacement range [p min p max [Middle displacement point p] o The displacement function p(t) passes through p units of time. o The number of times is used to obtain the claw tip sweep frequency function f(p) within the displacement range. o ), where p min Let p(t) be the minimum value of the displacement function. max Let p0 be the maximum value of the displacement function p(t), and p0 be the displacement range [p min p max One of the multiple discrete displacement points selected in the image;

[0012] S4. Constructing a basic wear model for conductive plastic films:

[0013] According to the claw tip sweep frequency function f(p) in step S3 o ), and combined with the claw tip contact pressure F(p) measured by the force gauge o ), construct a system for a single displacement point p o Basic wear model:

[0014] S5. Calculate the wear depth increment:

[0015] For displacement range [p min p max Each displacement point p in ] o The wear depth increment Δh(p0) is calculated to establish the wear rate model v(p0) for the entire displacement surface. The specific steps are as follows:

[0016] S51: Based on the fundamental model of a single displacement point p0, combined with the claw tip sweep frequency function f(po The contact pressure F(p) at the claw tip was measured using a force gauge. o ), calculate the wear depth increment Δh(p0) per unit time:

[0017] Δh(p o )=μF(p0) m ·f(p0);

[0018] S52: Determine the wear rate v(p0) of a single displacement point p0 based on the wear depth increment Δh(p0) per unit time:

[0019]

[0020] S53: Regarding the displacement range [p] min p max Each displacement point p in ] o Perform steps S51 and S52 to calculate the displacement range [p] min p max The wear rate of all displacement points within the displacement surface is calculated to obtain the wear rate model v(p).

[0021] S6. Determine the wear depth threshold:

[0022] The threshold value ΔR for reaching electrical performance failure was determined through electrical performance simulation of the potentiometer. th Wear depth Δh of conductive plastic film th This is used as the wear depth threshold Δh th ;

[0023] S7. Establishing a fretting wear life model:

[0024] Combining the wear rate model v(p0) constructed in step S5 and the wear depth threshold Δh in step S6 th A fretting wear life model for the potentiometer was established, and the final fretting wear life L of the potentiometer was calculated. s .

[0025] The fretting wear life model of the positioner is as follows:

[0026]

[0027] Among them, L s For the fretting wear life of the potentiometer, Δh th Δt is the threshold value for the fretting wear depth of the potentiometer. th p represents the wear time at each displacement point. min and p max These represent the maximum and minimum values ​​of the brush claw tip tremor displacement.

[0028] Preferably, in step S2, the vibration displacement spectrum A(ω) of the brush claw tip is transformed from the frequency domain to the time domain, specifically as follows:

[0029] The method for transforming the vibration displacement spectrum A(ω) from the frequency domain to the time domain is as follows: the frequency domain signal is decomposed into a series of sine waves using inverse Fourier transform, and the time domain signal p(t) is calculated based on the amplitude, frequency and phase of each sine wave. The time domain signal p(t) is the circumferential vibration displacement function of the brush claw tip, called the displacement function: i.e. p(t) = IFFT(A(ω)), where IFFT is the inverse Fourier transform operator.

[0030] Preferably, in step S3, the displacement function p(t) per unit time is statistically analyzed after p o The number of times, and the specific implementation steps are as follows:

[0031] S31: Randomly extract a signal of duration T from the displacement function p(t), and convert the extracted displacement function p(t) of duration T into a discrete signal p according to the set time step Δt0;

[0032] S32: For any time t in the discrete signal p i Check whether it meets (p(t) i )-p0)(p(t i+1 When )-p0)≤0, the time t for verification is met. i It can be regarded as in [t] i , t i+1 During this period, the claw tip displacement reaches position p0, and all times that meet the time t are counted. i The number of times n;

[0033] S33: Combining the number of times n the claw tip reaches position p0 within the discrete signal and the duration T of the discrete signal, the displacement function p(t) can be obtained per unit time. o The number of times, i.e., the claw tip sweep frequency function

[0034] Preferably, in step S31: the set time step T0 is the unit time, and the duration T of the intercepted displacement function p(t) is greater than 10 times the unit time T0.

[0035] Preferably, in step S4, a basic wear model is constructed for a single displacement point p0. The specific steps are as follows:

[0036] S41: Based on the abrasive wear mechanism of conductive plastic film furrows, the model form of the surface base wear model is determined based on the classic Archard model:

[0037]

[0038] In the formula, δh is the increase in wear depth when the brush tip passes through a specific point on the conductive plastic film in a single pass, C is the fretting wear coefficient of the friction pair, and H is the hardness of the conductive plastic film. Let μ be the fretting wear constant related to the friction pair material, F be the contact pressure between the brush and the conductive plastic film, and m be the pressure exponent.

[0039] S42: Based on the model form of the basic wear model in step S41, the parameter that needs to be determined is the dynamic wear constant. And the stress index m.

[0040] S43: Using the wear parameter identification test method, identify the two parameters to be determined in step S42, perform least squares fitting on the wear data obtained from the test, and output the fretting wear constants μ and m obtained from the fitting.

[0041] Preferably, in step S7, a fretting wear life model of the potentiometer is established, and the specific steps are as follows:

[0042] S71: Based on the wear depth threshold Δh th and displacement point p o The wear rate v(p0) is used to determine the displacement point p. o Wear time;

[0043] S72: For displacement range [p] min p max For each displacement point p in the image, proceed to step S71 to determine the wear time Δt at each displacement point. th ;

[0044] S73: Based on the wear time Δt at each displacement point in step S72 th A potentiometer fretting wear life model was constructed.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The method proposed in this invention is based on the vibration displacement statistics of the brush tip to construct a wear model of the conductive plastic film base, and combined with the actual vibration load spectrum of the potentiometer, a fretting wear life model of the potentiometer is established. The predicted life is basically consistent with the experimental results.

[0047] 2. The potentiometer fretting wear life model established according to the present invention can be used to quantitatively evaluate and predict the fretting wear life of potentiometers under actual working conditions, overcoming the problem that other methods are difficult to effectively quantify and predict the fretting wear life of potentiometers, and providing technical support for the evaluation of fretting wear life of conductive plastic potentiometers.

[0048] 3. Based on the fundamental wear model, this invention combines the claw tip sweep frequency function and claw tip contact pressure to obtain a wear rate model for the displacement surface. The algorithm is simple and effective, providing an effective solution for potentiometer wear prediction under real vibration environments. Compared with traditional potentiometer wear testing methods, this invention significantly reduces testing costs. Attached Figure Description

[0049] Figure 1 This is a flowchart of a method for evaluating the fretting wear life of a conductive plastic potentiometer according to the present invention;

[0050] Figure 2 It is the vibration displacement spectrum of the selected potentiometer brush claw tip according to an embodiment of the present invention;

[0051] Figure 3 It is the time-domain variation of the vibration displacement of the selected potentiometer brush claw tip according to an embodiment of the present invention;

[0052] Figure 4 This is a statistical histogram of the sweep frequency of the potentiometer brush claw tip selected in an embodiment of the present invention. Detailed Implementation

[0053] To better understand the technical solution of the present invention, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The same reference numerals in the drawings indicate elements with the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0054] This invention provides a method for assessing the fretting wear life of a conductive plastic potentiometer, such as... Figure 1 As shown, it includes the following steps:

[0055] S1. Calculate the vibration displacement spectrum of the brush claw tip:

[0056] Taking the potentiometer as a random vibration system, the random vibration load spectrum of the potentiometer housing is input. A numerical method is used to solve for the vibration displacement of the brush tips based on the vibration system response, and the vibration displacement spectrum A(ω) of the brush tips is output. Figure 2 As shown. The solution for the vibration system response in step S1 is implemented using existing technology, and the steps are as follows:

[0057] S11: Model the three-dimensional structure of each component of the vibration system, define the mechanical properties of the model based on the known material parameters of each component, and make it a vibration system that can calculate the vibration state of each point by virtually assembling and defining the relationship between the structures.

[0058] S12: Input the power spectral density of the overall random vibration acceleration or the frequency-amplitude spectrum of the deterministic vibration acceleration, and set it as the boundary condition for the potentiometer mounting location.

[0059] S13: Perform numerical solutions to analyze the vibration response at each point of the vibration system and output the vibration displacement spectrum A(ω) of the brush claw tip.

[0060] S2. Obtain the circumferential chatter displacement function of the brush claw tip:

[0061] The vibration displacement spectrum A(ω) of the brush claw tip output in step S1 is transformed from the frequency domain to the time domain to obtain the circumferential chattering displacement function p(t) of the brush claw tip.

[0062] The method for transforming the vibration displacement spectrum A(ω) from the frequency domain to the time domain is as follows: The frequency domain signal is decomposed into a series of sine waves using an inverse Fourier transform. The time domain signal p(t) is then calculated based on the amplitude, frequency, and phase of each sine wave. The time domain signal p(t) is the circumferential vibration displacement function of the brush tip, describing the displacement of the brush tip during vibration; it is simply called the displacement function. Figure 3 As shown (partial time-domain signal p(t)).

[0063] That is, p(t) = IFFT(A(ω)), where IFFT is the inverse Fourier transform operator.

[0064] S3, Statistical frequency of sweep points at displacement points:

[0065] Based on the displacement function p(t) in step S2, determine the displacement range of the displacement function p(t) [p min p max ], and for the displacement range [p min p max [Middle displacement point p] o The displacement function p(t) passes through p units of time. o The number of times is used to obtain the claw tip sweep frequency function f(p) within the displacement range. o ). Where p min Let p(t) be the minimum value of the displacement function. max Let p0 be the maximum value of the displacement function p(t), and p0 be the displacement range [p min p max One of the multiple discrete displacement points selected in ] .

[0066] The displacement function p(t) passes through p units of time. o The specific method for determining the number of times is as follows:

[0067] S31: Randomly extract a signal of a certain time duration T from the displacement function p(t), and adjust the time step according to the set time step. The displacement function p(t) of the intercepted time period T is converted into a discrete signal p, where Δt0 is the time step and T0 is the unit time. To reduce statistical error, the intercepted displacement function p(t) time period T should be greater than 10 times the unit time T0. In this example, the unit time is set to 1 second.

[0068] S32: For any time t in the discrete signal p i Check whether it meets (p(t) i )-p0)(p(t i+1 When )-p0)≤0, the time t for verification is met. i It can be regarded as in [t] i , t i+1 During this period, the claw tip displacement reaches position p0, and all times that meet the time t are counted. i The number of times n.

[0069] S33: Combining the number of times n the claw tip reaches position p0 within the discrete signal and the duration T of the discrete signal, the displacement function p(t) can be obtained per unit time. o The number of times, i.e., the claw tip sweep frequency function like Figure 4 As shown.

[0070] In this embodiment, the displacement range of the displacement function p(t) is [-1.35, 1.35]. Displacements that are multiples of 0.05 within this range are selected as displacement points. Alternatively, the displacement points can be selected by bisecting the distance between the displacement ranges, or even by using dense zero-point locations and sparse locations on both sides. The claw tip sweep frequency function f(p) is then statistically calculated for each displacement point. o The value of ).

[0071] S4. Constructing a basic wear model for conductive plastic films:

[0072] According to the claw tip sweep frequency function f(p) in step S3 o ), and combined with the claw tip contact pressure F(p) measured by the force gauge o ), construct a system for a single displacement point p o The basic wear model.

[0073] Construct a single displacement point p o The specific method for the basic wear model is as follows:

[0074] S41: Based on the abrasive wear mechanism of conductive plastic film furrows, the model form of the surface base wear model is determined based on the classic Archard model:

[0075]

[0076] In the formula, δh is the increase in wear depth when the brush tip passes through a specific point on the conductive plastic film in a single pass, C is the fretting wear coefficient of the friction pair, and H is the hardness of the conductive plastic film. Let μ be the fretting wear constant related to the friction pair material, F be the contact pressure between the brush and the conductive plastic film, and m be the pressure exponent.

[0077] S42: Based on the model form of the basic wear model in step S41, it can be seen that the parameter that needs to be determined is the dynamic wear constant. And the stress index m.

[0078] S43: Using existing wear parameter identification testing methods, a fretting friction and wear testing machine is used to identify the two parameters to be determined in step S42. The wear parameter identification test can be performed on the fretting friction and wear testing machine by measuring the average wear depth of the conductive plastic film at different times. In this embodiment, some information on the average wear depth of the conductive plastic film is shown in Table 1.

[0079] Table 1 Average wear depth of conductive plastic film

[0080] 1 6.4x10^4 0.063 2 3.2x10^5 0.137 3 1.6x10^6 0.267 4 8x10^6 0.508 5 4x10^7 1.177 … … …

[0081] The wear data obtained from the experiment can be fitted using least squares, and the fitted fretting wear constants μ and m can be output. In this embodiment, μ = 1.8345 × 10⁻⁶. -6 The pressure index m = 0.637.

[0082] S5. Calculate the wear depth increment:

[0083] For displacement range [p min p max Each displacement point p in ] o The wear depth increment Δh(p0) is calculated to establish the wear rate model v(p0) for the entire displacement surface. The specific steps are as follows:

[0084] S51: Based on the fundamental model of a single displacement point p0, combined with the claw tip sweeping frequency function f(p o The contact pressure F(p) at the claw tip was measured using a force gauge. o ), calculate the wear depth increment Δh(p0) per unit time:

[0085] Δh(p0)=μF(p0) m ·f(p0).

[0086] S52: Determine the wear rate v(p0) of a single displacement point p0 based on the wear depth increment Δh(p0) per unit time:

[0087]

[0088] With displacement range [p min p max Taking a displacement point p0 = 0.2 mm as an example, the wear rate of this displacement point v(p0) = 2.1962 × 10⁻⁶ mm. -5 mm / s.

[0089] S53: Regarding the displacement range [p] min p max Each displacement point p in ] o Perform steps S51 and S52 to calculate the displacement range [p] min p max The wear rate of all displacement points within the displacement surface is obtained by graphical method, which is used to obtain the wear rate model v(p) of the displacement surface.

[0090] S6. Determine the wear depth threshold:

[0091] According to the potentiometer's factory specifications, a change in the potentiometer's contact resistance exceeding 10% is set as the electrical performance failure threshold ΔR. th Based on the electrical performance failure threshold ΔR th Conduct electrical performance simulations of the potentiometer to determine the electrical performance failure threshold ΔR. th Wear depth Δh of conductive plastic film th This is used as the wear depth threshold Δh th .

[0092] The electrical performance simulation of the potentiometer focuses on the contact resistance simulation at the interface between the potentiometer brush and the conductive plastic film. In the embodiments of this patent, the electrical performance failure threshold ΔR... th =200Ω, the wear depth threshold Δh obtained from simulation th =2.76μm.

[0093] S7. Establishing a fretting wear life model:

[0094] Combining the wear rate model v(p0) of the entire displacement surface constructed in step S5 and the wear depth threshold Δh in step S6 th Calculate the displacement points p. i The wear depth threshold Δh reached th Over time, a fretting wear life model for the potentiometer was established, and the final fretting wear life L of the potentiometer was calculated. s .

[0095] The specific method for establishing the fretting wear life model of the potentiometer is as follows:

[0096] S71: Based on the wear depth threshold Δh determined in step S6 th and displacement point p o The wear rate v(p0) is used to determine the displacement point p.o Wear time

[0097] S72: For displacement range [p] min p max Each displacement point p in ] o Proceed to step S71 to determine the wear time Δt at each displacement point. th ;

[0098] S73: Based on the wear time Δt at each displacement point in step S72 th A potentiometer fretting wear life model is constructed as follows:

[0099]

[0100] In the formula, Ls is the fretting wear life of the potentiometer, and Δh th Δt is the threshold value for the fretting wear depth of the potentiometer. th p represents the wear time at each displacement point. min and p max Let Δt represent the maximum and minimum values ​​of the brush claw tip chatter displacement, and Δt be the duration of the overall load spectrum. Finally, the potentiometer fretting wear life L is determined based on the potentiometer fretting wear life model. s .

[0101] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for assessing the fretting wear life of a conductive plastic potentiometer, characterized in that: The specific steps are as follows: S1. Calculate the vibration displacement spectrum of the brush claw tip: The potentiometer is taken as a random vibration system. The random vibration load spectrum of the potentiometer housing is input. The vibration displacement of the brush claw tip is solved by numerical method based on the vibration system response, and the vibration displacement spectrum A(w) of the brush claw tip is output. S2. Obtain the circumferential chatter displacement function of the brush claw tip: The vibration displacement spectrum A(ω) of the brush claw tip is transformed from the frequency domain to the time domain to obtain the circumferential flutter displacement function p(t) of the brush claw tip; S3, Statistical frequency of sweep points at displacement points: Based on the displacement function p(t) in step S2, determine the displacement range of the displacement function p(t) [p min p max ], and for the displacement range [p min p max [Middle displacement point p] o The displacement function p(t) passes through p units of time. o The number of times is used to obtain the claw tip sweep frequency function f(p) within the displacement range. o ), where p min Let p(t) be the minimum value of the displacement function. max Let p0 be the maximum value of the displacement function p(t), and p0 be the displacement range [p min p max One of the multiple discrete displacement points selected in the image; S4. Constructing a basic wear model for conductive plastic films: According to the claw tip sweep frequency function f(p) in step S3 o ), and combined with the claw tip contact pressure F(p) measured by the force gauge o ), construct a system for a single displacement point p o Basic wear model: Where δh is the increase in wear depth when the brush tip passes through a specific point on the conductive plastic film in a single pass, C is the fretting wear coefficient of the friction pair, and G is the hardness of the conductive plastic film. The fretting wear constant μ is related to the friction pair material, F is the contact pressure between the brush and the conductive plastic film, and m is the pressure exponent; S5. Calculate the wear depth increment: For displacement range [p min p max Each displacement point p in ] o The wear depth increment Δh(p0) is calculated to establish the wear rate model v(p0) for the entire displacement surface. The specific steps are as follows: S51: Based on the fundamental model of a single displacement point p0, combined with the claw tip sweep frequency function f(p o The claw tip contact pressure F(p) measured by the force gauge o ), calculate the wear depth increment Δh(p0) per unit time: Δh(p0)=μF(p0) m ·f(f0); S52: Determine the wear rate v(p0) of a single displacement point p0 based on the wear depth increment Δh(p0) per unit time: S53: For displacement range [p] min p max Each displacement point p in ] o Perform steps S51 and S52 to calculate the displacement range [p] min p max The wear rate of all displacement points within the displacement surface is calculated to obtain the wear rate model v(p). S6. Determine the wear depth threshold: The threshold value ΔR for reaching electrical performance failure was determined through electrical performance simulation of the potentiometer. th Wear depth Δh of conductive plastic film th This is used as the wear depth threshold Δh th ; S7. Establishing a fretting wear life model: Combining the wear rate model v(p0) constructed in step S5 and the wear depth threshold Δh in step S6 th A fretting wear life model for the potentiometer was established, and the final fretting wear life L of the potentiometer was calculated. s ; The fretting wear life model of the potentiometer is as follows: Among them, L s For the fretting wear life of the potentiometer, Δh th Δt is the threshold value for the fretting wear depth of the potentiometer. th p represents the wear time at each displacement point. min and p max These represent the maximum and minimum values ​​of the brush claw tip tremor displacement.

2. The method for assessing the fretting wear life of a conductive plastic potentiometer according to claim 1, characterized in that: In step S2, the vibration displacement spectrum A(ω) of the brush claw tip is transformed from the frequency domain to the time domain, specifically as follows: The method for transforming the vibration displacement spectrum A(ω) from the frequency domain to the time domain is as follows: the frequency domain signal is decomposed into a series of sine waves using inverse Fourier transform, and the time domain signal p(t) is calculated based on the amplitude, frequency and phase of each sine wave. The time domain signal p(t) is the circumferential vibration displacement function of the brush claw tip, called the displacement function: i.e. p(t) = IFFT(A(ω)), where IFFT is the inverse Fourier transform operator.

3. The method for assessing the fretting wear life of a conductive plastic potentiometer according to claim 1, characterized in that: In step S3, the displacement function p(t) per unit time passes through p o The number of times, and the specific implementation steps are as follows: S31: Randomly extract a signal of duration T from the displacement function p(t), and convert the extracted displacement function p(t) of duration T into a discrete signal p according to the set time step Δt0; S32: For any time t in the discrete signal P i Check whether it meets (p(t) i )-p0)(p(t i+1 When )-p0)≤0, the time t for verification is met. i Considered as in [t i , t i+1 During this period, the claw tip displacement reaches position p0, and all times that meet the time t are counted. i The number of times n; S33: Combining the number of times n the claw tip reaches position p0 within the discrete signal and the duration T of the discrete signal, we obtain the displacement function p(t) passing through p within a unit time. o The number of times, i.e., the claw tip sweep frequency function 4. The method for assessing the fretting wear life of a conductive plastic potentiometer according to claim 3, characterized in that: In step S31: Set time step T0 is the unit time, and the duration T of the intercepted displacement function p(t) is greater than 10 times the unit time T0.

5. The method for assessing the fretting wear life of a conductive plastic potentiometer according to claim 1, characterized in that: In step S4, construct a system for a single displacement point p. o The basic wear model, the specific steps are as follows: S41: Based on the abrasive wear mechanism of conductive plastic film furrows, the model form of the surface base wear model is determined based on the classic Archard model: In the formula, δh is the increase in wear depth when the brush tip passes through a specific point on the conductive plastic film in a single pass, C is the fretting wear coefficient of the friction pair, and H is the hardness of the conductive plastic film. The fretting wear constant μ is related to the friction pair material, F is the contact pressure between the brush and the conductive plastic film, and m is the pressure exponent; S42: Based on the model form of the basic wear model in step S41, the parameter that needs to be determined is the dynamic wear constant. and the stress index m; S43: Using the wear parameter identification test method, identify the two parameters to be determined in step S42, perform least squares fitting on the wear data obtained from the test, and output the fretting wear constants μ and m obtained from the fitting.

6. The method for assessing the fretting wear life of a conductive plastic potentiometer according to claim 1, characterized in that: The specific steps for establishing the fretting wear life model of the potentiometer in step S7 are as follows: S71: Based on the wear depth threshold Δh th and displacement point p o The wear rate v(p0) is used to determine the displacement point p. o Wear time; S72: For displacement range [p] min p max Each displacement point p in ] o Proceed to step S71 to determine the wear time Δt at each displacement point. th ; S73: Based on the wear time Δt at each displacement point in step S72 th A potentiometer fretting wear life model was constructed.

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