A speed reducer power unit, speed control method and fault diagnosis method thereof

Abstract

The present invention discloses a reducer power unit, a speed control method and a fault diagnosis method thereof, comprising a motor housing and a driver arranged in the motor housing, the driver being connected to an eccentric shaft, the eccentric shaft driving a cycloid wheel to oscillate in a cycle, the cycloid wheel meshing with the reducer housing through a pin-tooth pin, a rubber-coated wheel sleeved on the outer side of the reducer housing for outputting power, an input end flange fixedly mounted on the end of the motor housing, and a reflective sticker being arranged on the end face of the rubber-coated wheel close to the input end flange. The present invention has a simple structure, and by adding a laser speed sensor and a reflective sticker, real-time and accurate measurement of the output speed of the power unit is achieved. Compared with the traditional method, which relies on the speed information fed back by the encoder as a reference, there is an inherent difference between the encoder measurement value and the actual output speed. Based on the above-mentioned high-precision speed detection means, the control system can continuously and finely adjust the output speed of the power unit.

Description

Technical Field

[0001] The present invention relates to the technical field of speed reducers, and in particular to a speed reducer power unit, a rotation speed control method and a fault diagnosis method thereof. Background Art

[0002] As an efficient and compact power transmission device, cycloid reducer has been widely used in industrial automation, robotics and various mechanical equipment. The traditional cycloid reducer power unit design usually assumes that the input power is relatively constant, so there are fewer control measures. However, in actual applications, this assumption may lead to unstable output speed, which in turn affects the performance and reliability of the entire system.

[0003] Most existing power unit speed control strategies rely on the speed information fed back by the encoder as a reference. Although this method can achieve speed control to a certain extent, the inherent difference between the encoder measurement value and the actual output speed leads to insufficient control accuracy. In addition, the existing systems generally lack effective fault diagnosis modules and cannot provide timely warnings when abnormal equipment operation occurs, which not only increases maintenance costs, but may also lead to more serious losses due to failure to deal with problems in a timely manner.

[0004] In order to overcome the above disadvantages, the present invention proposes a speed reducer power unit, a speed control method and a fault diagnosis method thereof. Summary of the invention

[0005] The object of the present invention is to provide a speed reducer power unit, a speed control method and a fault diagnosis method thereof to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a reducer power unit, comprising a motor housing and a driver arranged in the motor housing, the driver is connected to an eccentric shaft, the eccentric shaft drives the cycloid wheel to oscillate in a cycle, the cycloid wheel is meshed with the reducer housing through a pin pin for transmission, a rubber-coated wheel is sleeved on the outer side of the reducer housing for outputting power, an input end flange is fixedly installed at the end of the motor housing, a reflective sticker is provided on the end face of the rubber-coated wheel close to the input end flange, and a laser speed sensor is installed on the input end flange for receiving a reflected light signal emitted by the reflective sticker.

[0007] As a further solution of the present invention: an input end flange and an output end flange are respectively provided on both sides of the cycloidal wheel, and the input end flange and the output end flange are fixedly connected by bolts and a pin shaft penetrating the cycloidal wheel, and a pin shaft sleeve is installed in the contact area between the bolts and the pin shaft and the cycloidal wheel.

[0008] As a further solution of the present invention: an encoder for collecting motor signals is installed on the driver.

[0009] A speed control method for a reducer power unit comprises the following steps:

[0010] S1, collect the single-turn output speed ω of the rubber-wrapped wheel i ;

[0011] S2. After receiving the signal for the first time, set the reception of N signals as one cycle, and use the Newton interpolation algorithm within one cycle to obtain the output speed function ω(t) of the rubber-coated wheel within this cycle; in addition, after completing one cycle, the output speed function ω(t) of the rubber-coated wheel is recalculated. After the first cycle, the data of each cycle is used as the initial value of the last data of the previous cycle, and the output speed ω at any time is obtained. t ;

[0012] S3, will ω t Data and power unit target output speed ω T The difference is made and input into the controller for speed control to achieve precise control of the output speed and stabilize it near the target speed.

[0013] As a further solution of the present invention: in step S1, a reflective sticker is attached to the rubber-coated wheel, and a laser speed sensor is installed on the input end flange. When the rubber-coated wheel rotates one circle, the laser speed sensor will receive a reflected light signal, and the single-circle output speed ω of the rubber-coated wheel is calculated by the time difference between the two signals. i .

[0014] A method for diagnosing a fault of a reducer power unit comprises the following steps:

[0015] S1: Under the test environment, the encoder is used to collect the input speed ω of the power unit in normal state and fault state respectively. Ei , and the output speed ω collected by the laser speed sensor i , and use the time domain feature extraction method to extract features from the collected data;

[0016] S2: Use the support vector machine algorithm to train the collected data to obtain a fault diagnosis model, which is then applied to the power unit control system;

[0017] S3: After the power unit is running stably, data is collected in real time and input into the fault diagnosis model, the corresponding fault category is output and early warning prompts are given, and corresponding measures are taken in time according to the fault category.

[0018] As a further solution of the present invention: in step S1, a time domain feature extraction method is used to extract features from the collected data, specifically:

[0019] The input speed ω is collected by the encoderMi , and the output speed ω collected by the laser speed sensor i The actual transmission ratio n of the reducer is obtained by the following formula i ;

[0020] The actual transmission ratio of the reducer is

[0021] The time domain feature extraction method is mainly used to analyze the actual transmission ratio n of the reducer. i The maximum absolute value F1, mean F2, root mean square error F3, standard deviation F4, kurtosis F5, and skewness F6 are extracted:

[0022] The maximum absolute value is: F1 = max(n i |)

[0023] The mean is:

[0024] The root mean square error is:

[0025] The standard deviation is:

[0026] The kurtosis is:

[0027] The skewness is:

[0028] The maximum absolute value F1 is usually stable near the theoretical transmission ratio. If F1 is abnormal, it means that there is a problem with the health of the power unit equipment and there is a potential fault.

[0029] If the root mean square error F3 becomes abnormally large, it means that the power unit is unstable and there may be hidden dangers;

[0030] The kurtosis F5 reflects the impact characteristics of the data. If F3 is abnormal, it means that there is an impact in the power unit, which may cause damage and failure;

[0031] The skewness F6 reflects the asymmetry of the data. If F6 is abnormal, it means that the friction or collision in one direction of the power unit is large.

[0032] As a further solution of the present invention: in step S3, when the collected data is within the range of normal state, the reducer operates normally; when the collected data is within the range of fault state, the reducer issues an early warning and takes corresponding measures in time according to the fault type.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. This application realizes real-time and accurate measurement of the output speed of the power unit by adding a laser speed sensor and reflective tape. Compared with the traditional method, which relies on the speed information fed back by the encoder as a reference, there is an inherent difference between the encoder measurement value and the actual output speed. Based on the above-mentioned high-precision speed detection method, the control system can continuously and finely adjust the output speed of the power unit.

[0035] 2. In addition, a fault diagnosis module is incorporated into the power unit control system to promptly identify potential problems or abnormal conditions and provide early warning of fault categories. This preventive maintenance measure helps reduce unexpected downtime, extend the life of equipment, and ensure the safety of operators. When a possible fault is detected, the system will prompt you to take appropriate preventive or corrective measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the reducer power unit of the present invention;

[0037] Figure 2 It is a schematic diagram of the positions of the laser speed sensor and the reflective sticker of the present invention;

[0038] Figure 3 It is a cross-sectional schematic diagram of a speed reducer power unit of the present invention;

[0039] Figure 4 It is a structural schematic diagram of the cycloid wheel and the pin sleeve of the present invention;

[0040] Figure 5 It is a flow chart of the rotation speed control method and the fault diagnosis method of the present invention;

[0041] In the figure: 1. Rubber-coated wheel; 2. Needle pin; 3. Pin shaft; 4. Reflective tape; 5. Laser speed sensor; 6. Input end flange; 7. Motor housing; 8. Encoder; 9. Driver; 10. Eccentric shaft; 11. Reducer housing; 12. Pin shaft sleeve; 13. Cycloidal wheel; 14. Output end flange. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments 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.

[0043] See also Figure 1-5In an embodiment of the present invention, a reducer power unit includes a motor housing 7 and a driver 9 arranged in the motor housing 7, the driver 9 is connected to the eccentric shaft 10, the eccentric shaft 10 drives the cycloid wheel 13 to oscillate in a cycle, the cycloid wheel 13 is meshed with the reducer housing 11 through the pin pin 2 for transmission, a rubber-coated wheel 1 is sleeved on the outer side of the reducer housing 11 for outputting power, an input end flange 6 is fixedly installed at the end of the motor housing 7, a plurality of bolts are installed on the motor housing 7, and the motor housing 7 is connected to the input end flange 6 through a plurality of bolts, so that the staff can assemble the reducer conveniently; a reflective sticker 4 is provided on the end face of the rubber-coated wheel 1 close to the input end flange 6, and a laser speed sensor 5 is installed on the input end flange 6 for receiving the reflected light signal emitted by the reflective sticker 4.

[0044] See also Figure 3 In one embodiment, in this embodiment, preferably, an input end flange 6 and an output end flange 14 are respectively provided on both sides of the cycloidal wheel 13, and the input end flange 6 and the output end flange 14 are fixedly connected with the pin 3 by bolts penetrating the cycloidal wheel 13, and a pin sleeve 12 is installed in the contact area between the bolt and the pin 3 and the cycloidal wheel 13. Furthermore, since the cycloidal wheel 13 and the pin sleeve 12 are in direct contact, there will be greater friction during the movement, which will affect the output speed stability. Therefore, the material of the cycloidal wheel 13 is replaced with a material with a smaller friction coefficient, or the contact surface is treated accordingly to reduce friction and improve the operating stability of the cycloidal wheel 13.

[0045] See also Figure 3 In one embodiment, in this embodiment, preferably, an encoder 8 is installed on the driver 9 for collecting the input speed of the motor.

[0046] A speed control method for a reducer power unit comprises the following steps:

[0047] S1, collect the single-turn output speed ω of the rubber-wrapped wheel i ;

[0048] Specifically, in step S1, a reflective sticker 4 is attached to the rubber-coated wheel 1, and a laser speed sensor 5 is installed on the input end flange 6. When the rubber-coated wheel 1 rotates one circle, the laser speed sensor 5 will receive a reflected light signal. After the power unit is started and runs stably, the time when the laser speed sensor 5 receives the signal for the first time is recorded as time 0, and then t is calculated in real time based on the data of the laser speed sensor 5. i Output speed of rubber wheel at the momentω i The single-turn output speed of the rubber-coated wheel ω is obtained by the following formula: i :

[0049]

[0050] In the above formula, ti Indicates the time when the laser speed sensor last received a signal; t i-1 Indicates the time when the laser speed sensor last received a signal.

[0051] S2. After receiving the signal for the first time, set the reception of N signals as one cycle, N≧2. In this embodiment, N is equal to 5. Newton interpolation algorithm is used in one cycle to obtain the output speed function ω(t) of the rubber-coated wheel within this cycle; in addition, after completing one cycle, the output speed function ω(t) of the rubber-coated wheel is recalculated. After the first cycle, the data of each cycle is taken as the initial value of the last data of the previous cycle, and the output speed ω at any time is obtained. t ;

[0052] The specific process of fitting the rubber-wrapped wheel output speed function ω(t) is as follows:

[0053] (1) Define the function f(x), where f(t i )=ω i .

[0054] (2) is the first-order difference quotient of function f(x) about points t0 and t1, is the second-order difference quotient of function f(x), …, is the i-th order difference quotient of the function f(x).

[0055] (3) Let the i-th order interpolation polynomial be:

[0056] P i (t)=f(t0)+f[t0,t1](x-t0)+…+f[t0,t1,…,t i ](x-t0)…(xt i-1 ).

[0057] (4) When the speed data ω0 and ω1 are measured at points t0 and t1, the output speed function from t0 to t1 is:

[0058] ω(t)=P1(t)=f(t0)+f[t0,t1](x-t0)

[0059] When the speed value ω2 at time t2 is measured, the output speed function is updated from time t0 to time t2 as follows:

[0060] ω(t)=P2(t)=f(t0)+f[t0,t1](x-t0)+f[t0,t1,t2](x-t0)(x-t1)

[0061] By analogy, each time the speed data ω is measured i, update the output speed function ω(t). When i>5, a cycle ends. Update i=0, ω(t)=0, use the previous cycle ω5 as the initial value ω0 of this cycle, and recalculate the output speed function ω(t) of the new cycle.

[0062] S3, will ω t Data and power unit target output speed ω T The difference is made and input into the controller for speed control to achieve precise control of the output speed and stabilize it near the target speed.

[0063] A method for diagnosing a fault of a reducer power unit comprises the following steps:

[0064] S1: Under the test environment, the encoder 8 is used to collect the input speed ω of the power unit in normal state and fault state respectively. Ei , and the output speed ω collected by the laser speed sensor 5 i , and use the time domain feature extraction method to extract features from the collected data;

[0065] In step S1, the time domain feature extraction method is used to extract features from the collected data, specifically:

[0066] The input speed ω is collected by encoder 8 Mi , and the output speed ω collected by the laser speed sensor 5 i The actual transmission ratio n of the reducer is obtained by the following formula i ;

[0067] The actual transmission ratio of the reducer is

[0068] The time domain feature extraction method is mainly used to analyze the actual transmission ratio n of the reducer. i The maximum absolute value F1, mean F2, root mean square error F3, standard deviation F4, kurtosis F5, and skewness F6 are extracted:

[0069] The maximum absolute value is: F1 = max(n i |)

[0070] The mean is:

[0071] The root mean square error is:

[0072] The standard deviation is:

[0073] The kurtosis is:

[0074] The skewness is:

[0075] The maximum absolute value F1 is usually stable near the theoretical transmission ratio. If F1 is abnormal, it means that there is a problem with the health of the power unit equipment and there is a potential fault.

[0076] If the root mean square error F3 becomes abnormally large, it means that the power unit is unstable and there may be hidden dangers;

[0077] The kurtosis F5 reflects the impact characteristics of the data. If F3 is abnormal, it means that there is an impact in the power unit, which may cause damage and failure;

[0078] The skewness F6 reflects the asymmetry of the data. If F6 is abnormal, it means that the friction or collision in one direction of the power unit is large.

[0079] S2: Use the support vector machine algorithm to train the collected data to obtain a fault diagnosis model, which is then applied to the power unit control system;

[0080] The specific steps in step S2 are as follows:

[0081] S21. Establish a mathematical model: The goal of the support vector machine algorithm is to maximize the interval, that is, to maximize the distance from the hyperplane to the nearest support vector. The specific formula is as follows:

[0082]

[0083] In the formula, is the weight vector, b is the bias term, y i is the sample label.

[0084] S22. Convert the above constraints into an unconstrained optimization problem and solve it using the Lagrange multiplier method. Introduce the Lagrange multiplier α i Construct the Lagrangian function:

[0085]

[0086] Solve the function to find and the optimal value of b;

[0087] S23. Convert the original problem into a dual problem and find the optimal solution by solving the dual problem. The dual problem is in the form of:

[0088]

[0089] In the formula, K(x i ,x j ) is the kernel function, which is used to calculate the sample similarity.

[0090] S24. The final decision function is:

[0091]

[0092] Where b * are the parameters obtained during the optimization process.

[0093] S3: After the power unit is running stably, data is collected in real time and input into the fault diagnosis model, the corresponding fault category is output and early warning prompts are given, and corresponding measures are taken in time according to the fault category.

[0094] In step S3, when the collected data is within the range of normal state, the reducer operates normally; when the collected data is within the range of fault state, the reducer issues an early warning and takes corresponding measures in time according to the fault type.

[0095] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0096] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent changes made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A reducer power unit, comprising a motor housing and a driver arranged in the motor housing, characterized in that: The driver is connected to the eccentric shaft, and the eccentric shaft drives the cycloid wheel to oscillate in a cycle. The cycloid wheel is meshed with the reducer housing through a pin-tooth pin for transmission. A rubber-coated wheel is sleeved on the outer side of the reducer housing for outputting power. An input end flange is fixedly installed at the end of the motor housing, and a reflective sticker is provided on the end face of the rubber-coated wheel close to the input end flange. A laser rotation speed sensor is installed on the input end flange for receiving a reflected light signal emitted by the reflective sticker.

2. The reducer power unit according to claim 1, characterized in that: An input end flange and an output end flange are respectively provided on both sides of the cycloid wheel. The input end flange and the output end flange are fixedly connected by bolts and a pin shaft penetrating the cycloid wheel. A pin shaft sleeve is installed in the contact area between the bolt and the pin shaft and the cycloid wheel.

3. The reducer power unit according to claim 1, characterized in that: An encoder for collecting motor signals is installed on the driver.

4. A speed control method for a reducer power unit, characterized in that: The following steps are involved: S1, collect the single-turn output speed ω of the rubber-wrapped wheel i ; S2. After receiving the signal for the first time, set the reception of N signals as one cycle, and use the Newton interpolation algorithm within one cycle to obtain the output speed function ω(t) of the rubber-coated wheel within this cycle; in addition, after completing one cycle, the output speed function ω(t) of the rubber-coated wheel is recalculated. After the first cycle, the data of each cycle is used as the initial value of the last data of the previous cycle, and the output speed ω at any time is obtained. t ; S3, will ω t Data and power unit target output speed ω T The difference is made and input into the controller for speed control to achieve precise control of the output speed and stabilize it near the target speed.

5. The speed control method according to claim 4, characterized in that: In step S1, a reflective sticker is attached to the rubber-coated wheel, and a laser speed sensor is installed on the input flange. When the rubber-coated wheel rotates one circle, the laser speed sensor will receive a reflected light signal, and the single-circle output speed ω of the rubber-coated wheel is calculated by the time difference between the two signals. i .

6. A fault diagnosis method for a reducer power unit, characterized in that: The following steps are involved: S1: Under the test environment, the encoder is used to collect the input speed ω of the power unit in normal state and fault state respectively. Ei , and the output speed ω collected by the laser speed sensor i , and use the time domain feature extraction method to extract features from the collected data; S2: Use the support vector machine algorithm to train the collected data to obtain a fault diagnosis model, which is then applied to the power unit control system; S3: After the power unit is running stably, data is collected in real time and input into the fault diagnosis model, the corresponding fault category is output and early warning prompts are given, and corresponding measures are taken in time according to the fault category.

7. The fault diagnosis method of the reducer power unit according to claim 6, characterized in that: In step S1, the time domain feature extraction method is used to extract features from the collected data, specifically: The input speed ω is collected by the encoder Mi , and the output speed ω collected by the laser speed sensor i The actual transmission ratio n of the reducer is obtained by the following formula i ; The actual transmission ratio of the reducer is The time domain feature extraction method is mainly used to analyze the actual transmission ratio n of the reducer. i The maximum absolute value F1, mean F2, root mean square error F3, standard deviation F4, kurtosis F5, and skewness F6 are extracted: The maximum absolute value is: F1 = max(n i |) The mean is: The root mean square error is: The standard deviation is: The kurtosis is: The skewness is: The maximum absolute value F1 is usually stable near the theoretical transmission ratio. If F1 is abnormal, it means that there is a problem with the health of the power unit equipment and there is a potential fault. If the root mean square error F3 becomes abnormally large, it means that the power unit is unstable and there may be hidden dangers; The kurtosis F5 reflects the impact characteristics of the data. If F3 is abnormal, it means that there is an impact in the power unit, which may cause damage and failure; The skewness F6 reflects the asymmetry of the data. If F6 is abnormal, it means that the friction or collision in one direction of the power unit is large.

8. The fault diagnosis method of the reducer power unit according to claim 6, characterized in that: In step S3, when the collected data is within the range of normal state, the reducer operates normally; when the collected data is within the range of fault state, the reducer issues an early warning and takes corresponding measures in time according to the fault type.

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