TWI731699B - Method for predicting and compensating frictions of feed system, and computer readable medium - Google Patents

Abstract

A method for predicting and compensating frictions of feed system is disclosed and includes following steps: constantly obtaining current signal and angle-position signal of a motor by a motor driver of a feed system after it is activated; calculating multiple records of friction data of the motor, while the motor rotates, upon each rotating position according to the obtained current signal and angle-position signal; establishing a friction model according to the multiple records of friction data and multiple records of the angle-position signal respectively corresponding to each record of the friction data with respect to each rotating position; importing current angle-position signal of the motor into the friction model for predicting a predicted friction of the feed system; calculating a compensation current based on the predicted friction; and, controlling the motor driver to additionally provide the compensation current to the motor for overcoming the friction for the feed system.

Description

Friction force prediction and compensation method of feed system and computer readable storage medium

The present invention relates to a feed system, in particular to a friction force prediction and compensation method of the feed system.

Generally speaking, the motor used in the feed system (such as automation equipment) will have speed discontinuity at the moment of reversing because there is not enough power to overcome the maximum static friction generated by the mechanical components. Processing lines are generated in each direction, which affects the processing quality and precision of the feed system.

Refer to Figure 1, which is a schematic diagram of the feed system and friction. As shown in Figure 1(a), the feed system 1 is generally equipped with one or more sets of mechanical components 11. After the feed system 1 is started, the motor (not shown in the figure) can be controlled to rotate, and the rotation of the motor can be used to The mechanical assembly 11 is driven to move repeatedly in directions such as up, down, left, right, front, and back, so as to achieve the purpose of processing.

To drive the mechanical assembly 11 to move in the opposite direction, the motor must be reversed. As mentioned above, the motor will not be able to overcome the static friction force caused by the mechanical assembly 11 due to insufficient power at the moment of reverse rotation, so a circular trajectory 2 as shown in FIG. 1(b) will be formed. As shown in Figure 1(b), the feed system 1 There will be sharp corners at the reversing point 20 of the motor, which means that the power of the motor at the reversing point 20 is not enough to cope with the corresponding friction.

In order to solve the above-mentioned problems, those skilled in the art really need a set of novel systems and methods. They can analyze the motors of the feed system to predict the power required by the motors to overcome the frictional forces at various rotational positions. To compensate, and to improve the processing quality and precision of the feed system.

The main purpose of the present invention is to provide a method for predicting and compensating the friction force of a feed system and a computer-readable storage medium, which can predict the friction force after the feed system is started, and provide additional compensation by the motor Electric current to overcome the predicted friction.

In order to achieve the above-mentioned purpose, the friction prediction and compensation method of the feed system of the present invention is applied to a feed system. The feed system has at least one set of mechanical components, a motor that guides the mechanical components to act, and electrical connections. The motor also controls a motor driver that controls the rotation of the motor, and the friction prediction and compensation method of the feed system includes at least the following steps: a) The motor driver continuously captures a current signal and a corner position signal when the motor is rotating; b) According to the current The signal and the angular position signal estimate the friction of the motor at each rotation position, and generate multiple friction data; c) Perform calculations based on the multiple friction data and the angular position signal corresponding to each friction data to establish the motor A friction model; d) Incorporate the current angular position signal of the motor into the friction force model to predict a predicted friction force of the feed system; e) calculate a compensation current based on the predicted friction force; and f) control the motor driver to apply additional compensation current to motor.

In order to achieve the above-mentioned purpose, the computer-readable storage medium of the present invention records a computer-readable program code, and after the program code is executed, the following steps can be performed: a) Continued by a motor drive of a feed system Capture a current signal and an angular position signal when a motor of the feed system rotates; b) Estimate a friction force of the motor at each rotation position based on the current signal and angular position signal, and generate multiple friction data; c) Perform calculations based on multiple friction data and angular position signals corresponding to each friction data to establish a friction model for the motor; d) incorporate the current angular position signal of the motor into the friction model to predict a feed system Predict the friction force; e) calculate a compensation current based on the predicted friction force; and f) control the motor driver to additionally apply a compensation current to the motor.

Compared with the related art, the feed system of the present invention can provide an additional compensation current to the motor, so that the motor can overcome the friction on the feed system when the motor is running, thereby overcoming the problem of insufficient power when the motor is reversed. , And then improve the processing quality and precision that the feed system can provide.

In addition, by continuously predicting and monitoring the friction force, the present invention can also determine the current health status of the feed system based on the friction related parameters at different time points, and then determine whether the feed system needs maintenance or replacement.

1, 3: Feed system

11, 33: mechanical components

2: Follow a circular trajectory

20: Reversing point

31: Motor drive

311: Application

312: Friction Model

32: Motor

331: bed

332: Slide

333: Stage

41: Follow a circular trajectory before compensation

42: Follow circular trajectory after compensation

S10~S26: Compensation steps

S30~S50: update steps

S60~S82: Evaluation steps

Figure 1 is a schematic diagram of the feed system and friction.

Fig. 2 is a first specific embodiment of a block diagram of the feeding system of the present invention.

Fig. 3 is a first specific embodiment of a flowchart of the prediction and compensation method of the present invention.

Fig. 4 is a first specific embodiment of the friction force comparison schematic diagram of the present invention.

Fig. 5 is a first specific embodiment of the friction force model update flowchart of the present invention.

Fig. 6 is a first specific embodiment of the health state assessment flowchart of the present invention.

With regard to a preferred embodiment of the present invention, the detailed description is given below in conjunction with the drawings.

The present invention discloses a method for predicting and compensating the friction force of the feed system, which is mainly used to predict the friction force during the operation of the feed system, and timely compensate the motor inside the feed system, thereby avoiding the problem of the motor. The power is not enough to overcome the friction of the feed system and affect the processing quality and precision provided.

Firstly, please refer to FIG. 2, which is a first specific embodiment of the block diagram of the feeding system of the present invention. The friction force prediction and compensation method of the present invention (hereinafter referred to as the compensation method in the specification) is mainly applied to the feed system 3 as shown in FIG. 2. In the embodiment of FIG. 2, the feed system 3 mainly includes a motor driver 31, a motor 32 that is electrically connected to the motor driver 31 and controlled by the motor driver 31, and at least one that is pulled by the rotation of the motor 32 to perform relative operations. Group mechanical components 33.

In the embodiment of FIG. 2, the feeding system 3 is an automated equipment. The mechanical assembly 33 includes a bed 331, a plurality of slide rails 332 arranged on the bed 331, and a slide rail 332. The upper carrier 333, wherein the carrier 333 can be pulled by the rotation of the motor 32 to move back and forth on the bed 331 along the sliding rail 332. However, the above description is only one specific embodiment of the present invention, but it is not limited to the above.

In this embodiment, an application program 311 is stored in the motor driver 31, and the motor driver 31 can implement the compensation method of the present invention by executing the application program 311. Specifically, the compensation method of the present invention mainly monitors and captures the rotation data of the motor 32 through the motor driver 31, and estimates the friction force on the feed system 3 (for example, when the motor 32 is at each rotation position) based on these rotation data The maximum static friction brought by the mechanical component 33). Based on the estimated friction force, the application 311 can further establish a friction force model 312 for the state of the motor 32.

In the present invention, the frictional force model 312 is mainly a function of frictional force and position (detailed later). The aforementioned frictional force refers to the frictional force that the motor 32 needs to overcome during the operation of the feed system 3, and the aforementioned position refers to the various rotational positions of the motor 32.

With the friction force model 312 established, the application 311 can easily predict the friction force that the feed system 3 will face during the operation of the feed system 3, and control the motor driver 31 to compensate for the rotation of the motor 32. This allows the motor 32 to overcome the actual friction force in accordance with the prediction. Through the compensation method of the present invention, the feed system 3 can effectively eliminate the reversing sharp angle of the motor 32 at the reversing position. By timely providing the motor 32 with enough power to overcome the friction at different time points, the feed system 3 can be improved. 3. The processing quality and precision that can be provided.

In the embodiment of FIG. 2, at least one computer-readable storage medium (not shown in the figure) is configured inside the motor driver 31, such as a hard disk, non-volatile memory, flash memory, or read-only memory. Not limited. The computer-readable storage medium records a program code that can be executed by the computer, And the aforementioned application program 311 is constituted by the program code. After the motor driver 31 executes the relevant code in the application program 311, it can execute each step of the compensation method of the present invention.

In other embodiments, the computer-readable storage medium may also exist independently in an external device such as a controller, a personal computer, a notebook computer, or a server connected to the feeding system 3. In this embodiment, the program code (ie, the application program 311) can be executed by an external device such as a controller, a personal computer, a notebook computer, or a server connected to the feeding system 3, and the program code (ie, the application program 311) can be executed after being executed. The system 3 is controlled to execute each step in the compensation method of the present invention through the feeding system 3, and is not limited to the structure shown in FIG. 2.

Please also refer to FIG. 3, which is the first specific embodiment of the flow chart of the prediction and compensation method of the present invention. FIG. 3 discloses the detailed steps of the compensation method of the present invention, and the compensation method of the present invention is mainly applied to the feeding system 3 shown in FIG. 2, but is not limited.

First, the user activates the feeding system 3 when necessary (step S10). After the feeding system 3 is activated, the application program 311 is executed by the motor driver 31 or the aforementioned controller, personal computer, notebook computer, or server connected to the feeding system 3, so as to be executed by the application program 311 To control the feeding system 3 to implement the compensation method of the present invention. For ease of description, the following will take the application program 311 executed by the motor driver 31 in the feed system 3 as an example for description.

After step S10, the motor driver 31 controls the motor 32 to rotate, and continuously captures the current signal and the angular position signal when the motor 32 rotates (step S12). Specifically, the current signal is used to indicate the magnitude of the current received when the motor 32 is at each rotation position, and the angular position signal is used to indicate the current rotation position of the motor 32.

In one embodiment, the motor driver 31 can continuously control the motor 32 to rotate after the feed system 3 is activated, and continuously capture the current signal and the angular position signal of the motor 32. To another In an embodiment, the motor driver 31 may first control the motor 32 to perform a circular motion after the feed system 3 is activated, and sequentially capture the current signal and the angular position signal when the motor 32 is at each rotation position during the circular motion. Until the circular motion is completed. However, the foregoing are only part of the specific implementation examples of the present invention, but are not limited to the foregoing.

When the motor driver 31 obtains sufficient data (for example, the number of current signals and angular position signals is greater than the threshold value), the motor driver 31 can estimate the motor 32 separately based on the current signals and angular position signals of the motor 32 at each rotation position The friction force at each rotation position, and multiple pieces of friction force data are generated (step S14). Specifically, in step S14, the motor driver 31 estimates the friction force faced by the feeding system 3 when the motor 32 is at each rotation position, and records it as multiple friction data.

In one embodiment, the motor driver 31 can mainly calculate the friction force of the motor 32 at each rotation position according to the following two sets of formulas: Formula 1: C _m =J×α+sgn(ω)×f _c +ω×B +C _g .

Formula 2: C _f =C _m -J×α-ω×BC _g .

In the above formula 1 and formula 2, C _m is the current signal, J is the moment of inertia of the motor 32 , α is the angular acceleration of the motor 32, ω is the angular velocity of the motor 32, sgn() represents the forward and reverse information of the motor 32, f _c is the Coulomb friction force, B is the viscous friction coefficient, C _g is a constant, and C _f is the friction force of the feed system 3.

In formula 1, the motor driver 31 can first calculate the angular acceleration α and the angular velocity ω of the motor 32 according to the angular position signal of the motor 32 at each rotational position and the corresponding time, and then estimate the above-mentioned moment of inertia J by the least square method , Viscous friction coefficient B, Coulomb friction force f _c and constant C _g . The least square method is a common technical means in the technical field, and will not be repeated here.

The current signal C _m , angular acceleration α, and angular velocity ω of the motor 32 are known (under some hardware architectures, the current signal C _m , angular acceleration α, and angular velocity ω may be directly obtained from the motor driver 31 ), and When the moment of inertia J, the coefficient of viscous friction B and the constant C _{g are calculated, the motor driver 31 can calculate the friction force C f of the} feed system 3 when the motor 32 is at each rotation position according to the above formula 2.

After step S14, the motor driver 31 further performs calculations based on the multiple pieces of estimated friction data (respectively corresponding to the different rotation positions of the motor 32) and the angular position signals corresponding to each piece of friction data, so as to establish one for the motor 32 Friction force model 312 (step S16).

Specifically, the motor driver 31 in step 16 mainly establishes the friction force model 312 according to the following formula:

In the above formula three, u is the step function, a _i is the first model parameter, b _i is the second model parameter, c _i is the third model parameter, and d is the fourth model parameter.

In one embodiment, the motor driver 31 mainly performs a curve fitting operation on the friction force of the motor 32 at each rotation position based on the above formula three to obtain the first model parameter, the second model parameter, and the first model parameter. Three model parameters and fourth model parameters. After the first model parameter, the second model parameter, the third model parameter, and the fourth model parameter are known, the motor driver 31 can establish the friction force model 312.

As mentioned above, the friction force model 312 in the present invention is a function of friction force and position, which means that during the operation of the feed system 3, only the current rotational position (ie, the angular position signal) of the motor 32 is integrated Into the friction force model 312, the current friction force of the feed system 3 can be directly obtained, And it can predict the friction force that the feed system 3 will face (that is, corresponding to the next rotation position of the motor 32).

In one of the embodiments of the present invention, the friction force estimation procedure in step S14 and the friction force model establishment procedure in step 16 can be continuously executed in the background. In other words, after the feed system 3 is activated, the motor driver 31 can continuously estimate the friction force of the motor 32 at each rotational position through the execution of the application program 311, and continue to build/update the friction force model 312, but does not apply it. limited.

Specifically, the state of the motor 32 may change with the operating time of the feed system 3 (for example, wear, insufficient lubricating oil, etc.), resulting in a change in the overall friction. In view of this, by continuously executing the steps S14 and S16 in the background, the friction force model 312 can be closer to the current state of the motor 32, and the friction force predicted by the friction force model 312 can be more accurate.

After step S16, the motor driver 31 obtains the current angular position signal of the motor 32 (step S18), and incorporates the angular position signal into the friction force model 312 to directly obtain the corresponding predicted friction force through the friction force model 312 (step S20) . In this embodiment, the motor driver 31 mainly incorporates the current angular position signal of the motor 32 into the friction force model 312 to obtain the friction force of the feed system 3 when the motor 32 reaches the next rotation position (that is, the said Predict friction). In this way, the motor driver 31 can compensate the friction force that the feed system 3 is about to face in advance.

After step S20, the motor driver 31 further executes a specific algorithm or a look-up table method (not shown in the figure) based on the obtained predicted friction force to calculate the corresponding compensation current (step S22). Then, the motor driver 31 additionally applies the compensation current to the motor 32 (step S24), so that the motor 32 has sufficient power to overcome the actual friction force in accordance with the prediction. Specifically, the magnitude of the compensation current corresponds to the magnitude of the predicted frictional force. When the motor 32 receives the compensation current, its rotational force is sufficient to overcome the frictional force of the feed system 3 to rotate smoothly.

After step S24, the motor driver 31 determines whether the feed system 3 is closed (step S26), and continues to execute steps S18 to S24 before the feed system 3 is closed, so as to continuously obtain information based on the current rotation position of the motor 32 The friction force is predicted, and additional compensation current is continuously provided to the motor 32 based on the predicted friction force.

In one embodiment, the motor driver 31 continuously outputs current to the motor 32 during the operation of the feeding system 3 to make the motor 32 rotate. As mentioned above, at the moment when the motor 32 is reversed (for example, when the mechanical assembly 33 is to be controlled to move in the opposite direction), the motor 32 will not have enough power to overcome the friction of the feed system 3, so the motor 32 Discontinuous speed occurs at the commutation point. Therefore, in the aforementioned step S24, the motor driver 31 additionally applies the compensation current to the motor 32, so that the motor 32 has sufficient power to overcome the actual friction that is about to be faced.

However, the foregoing is only one of the specific implementation examples of the present invention. The compensation method of the present invention is not limited to being applied to the reversing position of the motor, but can be continuously applied during the operation period of the feed system 3.

Please also refer to FIG. 4, which is a first specific embodiment of the friction force comparison schematic diagram of the present invention. FIG. 4 shows the circular trajectory 41 before compensation and the circular trajectory 42 after compensation of the motor 32. Specifically, the circular trajectory 41 before compensation records the trajectory generated by the circular motion of the control motor 32 when the compensation method of the present invention is not used, and the circular trajectory 42 after compensation records the trajectory generated by the compensation method of the present invention. After the method, the motor 32 is controlled to follow the trajectory generated by the circular motion.

It can be clearly seen from FIG. 4 that before the compensation method of the present invention is used (that is, regardless of the friction force, the motor driver 31 will not provide additional compensation current to the motor 32), the motor 32 will appear at the commutation position. Obviously sharp reversing angles indicate that the motor 32 does not have enough power to overcome the frictional force and discontinuous speed occurs when the motor 32 rotates in the reverse direction. In contrast, after using the compensation method of the present invention Later, the quadrant error of the motor 32 at the commutation position has been greatly reduced. This is because the power of the motor 32 during reverse rotation has been compensated in advance by the additional compensation current provided by the motor driver 31, so the compensation of the motor 32 follows a circular trajectory 42 It will be more stable than following the circular trajectory 41 before compensation.

As mentioned above, in order to make the friction force model 312 more consistent with the current state of the motor 32, and thereby make the prediction of the friction force more accurate, the present invention enables the motor driver 31 to continuously perform the friction force model 312 through the execution of the application program 311. Update. However, continuously updating the friction force model 312 will consume more computing resources of the motor driver 31. Therefore, in another embodiment, the motor driver 31 can update the friction force model 312 when necessary.

Refer to FIG. 5, which is a first specific embodiment of the friction force model update flowchart of the present invention. In this embodiment, the user first controls the feeding system 3 to start when needed (step S30). After the feed system 3 is started, the motor driver 31 controls the motor 32 to rotate, and the motor driver 31 (or an external device connected to the feed system 3) can execute the application program 311 to continuously capture the current of the motor 32 Signals and angular position signals (step S32). Based on the captured current signals and angular position signals, the friction force of the motor 32 at each rotation position is estimated, and then the friction force model 312 is established (step S34).

In this embodiment, the friction force model 312 established by the motor driver 31 in step S34 is the first friction force model, and the motor driver 31 regards the first friction force model as an estimated friction force model of the feed system 3 (step S36). After the estimated friction force model is established, the motor driver 31 can incorporate the current angular position signal of the motor 32 into the estimated friction force model to perform the friction compensation action as described above (that is, based on the predicted friction force). Force to provide additional compensation current to the motor 32).

After step S36, the motor driver 31 continues to capture the current signal and angular position signal of the motor 32 (step S38), and re-estimates the friction force of the motor 32 at each rotation position, and generates multiple friction data, and then according to Re-estimated friction data and corresponding The angular position signals of each friction force are calculated to establish a second friction force model (step S40). The establishment of the above-mentioned second friction force model refers to controlling the motor 32 to perform at least one circular motion, and perform the circular motion at least once. The current signal and the angular position signal of the motor 32 when the motor 32 is at each rotation position are sequentially captured. In this embodiment, the motor driver 31 establishes the estimated friction force model (that is, the first friction force model) and the second friction force model based on the same method, but the time point for establishing the second friction force model is later than establishing the estimated friction force model. The time point of the friction force model, therefore, the predicted friction force based on the second friction force model is closer to the current state of the motor 32 than the predicted friction force based on the estimated friction force model.

After step S40, the motor driver 31 compares the estimated friction force model with the second friction force model (step S42) to determine whether the difference between the estimated friction force model and the second friction force model is smaller than the first threshold Value (step S44). In this embodiment, the motor driver 31 determines which friction force model is to be used to predict the friction force during the next operation period based on the difference between the estimated friction force model and the second friction force model.

As shown in Fig. 5, if the difference between the estimated friction force model and the second friction force model is less than the first threshold, it means that the estimated friction force model established earlier still conforms to the current state of the motor 32, and therefore the motor driver 31 directly The second friction force model established later is discarded (step S46), and the estimated friction force model is maintained to predict the friction force of the feed system 3.

If the difference between the estimated friction force model and the second friction force model is not less than the first threshold value, it means that the friction force predicted by the estimated friction force model does not meet the current state of the motor 32, so the motor driver 31 directly The established second friction force model is used to update the estimated friction force model established earlier (or directly replace the estimated friction force model), which means that the second friction force model is used as the new estimated friction force model (step S48 ).

After step S46 and step S48, the motor driver 31 determines whether the feed system 3 is turned off (step S50), and repeatedly executes steps S38 to S48 before the feed system 3 is turned off to continuously establish the second friction force model , Continue to update the estimated friction model, and continue to use the estimated friction model to predict the friction of the feed system 3 until the feed system 3 is turned off.

With the technical solution disclosed in FIG. 5, the motor driver 31 continuously monitors the current signal and the angular position signal when the motor 32 rotates, but does not need to frequently update the estimated friction force model used to predict the friction force of the feed system 3. The efficiency of the motor driver 31 can be moderately saved.

It is worth mentioning that in the above step S42, the motor driver 31 mainly calculates the relative error between the complex model parameters in the estimated friction force model and the complex model parameters in the second friction force model to determine the estimated friction. Whether the difference between the force model and the second friction force model is smaller than the first threshold value.

。然而，因為建立模型時所採用的數據(即，電流訊號、角位置訊號)不同，因此估測摩擦力模型與第二摩擦力模型中的模型參數(例如公式三中的a_i、b_i、c_i、d)的數值會所有不同。 In one embodiment, the estimated friction force model and the second friction force model are both the formula three disclosed above:

. However, because the data used to build the model (ie, current signal, angular position signal) are different, the model parameters in the estimated friction force model and the second friction force model (for example, a _i , b _i , The values of c _i and d) will all be different.

、

，以此類推)，並且判斷該些模型參數的相對誤差是否分別小於所述第一門檻值。上述相對誤差的運作屬於本技術領域的常用技術手段，於此不再贅述。 In this embodiment, the motor driver 31 mainly calculates the relative error between the complex model parameter in the estimated friction force model and the complex model parameter in the second friction force model (for example,

,

, And so on), and determine whether the relative errors of these model parameters are respectively smaller than the first threshold value. The operation of the above relative error belongs to the common technical means in the technical field, and will not be repeated here.

In this embodiment, the motor driver 31 directly discards the second friction force model when the relative errors of the model parameters are smaller than the first threshold value, and maintains the friction force estimation model to perform the friction force prediction action of the feed system 3 . In addition, when the relative error of one or more model parameters is not less than the first threshold value, the motor driver 31 directly replaces the friction force estimation model established earlier with the second friction force model established later, and uses it instead. The second friction force model performs the friction force prediction operation of the feed system 3.

With the above technical solution, the compensation method of the present invention can predict the friction force of the feed system 3 through the friction force model 312, and then provide an additional compensation current to the motor 32 of the feed system 3 to compensate for the friction force. In this way, the processing quality and precision of the feed system 3 can be effectively improved.

Another technical solution of the present invention is that by monitoring the complex model parameters in the friction force model 312 for a long time, the compensation method of the present invention can further determine the current health status of the feeding system 3 (and the motor 32).

Refer to FIG. 6, which is a first specific embodiment of the health state assessment flowchart of the present invention. As shown in Figure 6, the user first activates the feed system 3 (step S60). After the feed system 3 is activated, the motor driver 31 controls the motor 32 to rotate, and captures the current signal and angle of the motor 32 during rotation. Position signal (step S62). In addition, the motor driver 31 estimates the friction force of the motor 32 at each rotation position based on the captured current signal and the angular position signal, and thereby establishes the friction force model 312 (step S64).

It is worth mentioning that the friction model 312 established in the above step S64 refers to capturing the motor 32 under the best condition of the motor 32 (for example, the motor has just been replaced with a new one, or the maintenance operation of the motor has just been completed). Current signals and angular position signals, and based on these current signals and angular position signals. Established a reference friction model. More specifically, the friction force predicted by the reference friction force model will correspond to the friction force at each rotation position when the motor 32 rotates in an optimal state.

After the establishment of the reference friction force model is completed, the motor driver 31 can perform the friction force compensation action of the feed system 3 by using the reference friction force (step S66). The friction compensation action in this embodiment is similar to steps S18 to S24 shown in FIG. 3 (that is, the angular position signal of the motor 32 is incorporated into the reference friction model 12 to obtain the predicted friction force, and based on the predicted friction force Calculate and provide the corresponding compensation current), which will not be repeated here.

During the operation of the feeding system 3, the motor driver 31 continuously records the operating time of the feeding system 3, and determines whether the preset inspection period has passed (step S68). In the technical solution disclosed in FIG. 6, the motor driver 31 mainly determines whether to perform an assessment of the health status of the feeding system 3 based on whether the inspection period has elapsed or not. More specifically, the motor driver 31 evaluates the current health status of the motor 32 of the feeding system 3 when the operation time of the feeding system 3 is longer than the inspection period.

In one embodiment, the inspection period is two to four weeks from when the feed system 3 is started, the motor 32 is replaced, or the motor 32 completes maintenance, but it is not limited to this.

If it is determined in step S68 that the inspection period has not elapsed, it means that there is no need to assess the health status of the feed system 3 at present, so the motor driver 31 will perform step S66 again to continue according to the reference friction model (or as shown in Fig. 5). The estimated friction force described in the embodiment) predicts and compensates the friction force of the feed system 3.

If it is determined in step S68 that the inspection period has exceeded, it means that the health status of the feeding system 3 needs to be evaluated at present, and therefore the motor driver 31 is based on the current signal and the angular position of the motor 32 in real time. The setting signal estimates the current friction force of the motor 32 at each rotation position, and establishes another friction force model 312 based on the multiple friction forces and the corresponding angular position signals (step S70).

In the above step S70, the motor driver 31 may, for example, control the motor 32 to perform a circular motion again, and sequentially record the current signal and angular position signal of the motor 32 during the circular motion to estimate the current state of the motor 32. Friction at each rotational position.

The friction model 312 established in step S70 refers to capturing the current signal and angular position signal of the motor 32 (that is, after having rotated for a period of time equivalent to the aforementioned inspection period), and based on these current signals and A test friction model established by the angular position signal. More specifically, the friction force predicted by the test friction force model will match the friction force at each rotation position when the motor 32 rotates in the current state.

After step S70, the motor driver 31 compares the reference friction force model with the test friction force model (step S72) to determine whether the difference between the reference friction force model and the test friction force model is less than the second threshold value (step S74). ). In this embodiment, the motor driver 31 evaluates the current health status of the feed system 3/motor 32 based on the difference between the reference friction model and the test friction model.

If the difference between the reference friction model and the test friction model is less than the second threshold value, it means that the state of the feed system 3/motor 32 has not changed much, so the motor driver 31 will determine that the feed system 3 is still in a healthy state ( Step S76), so there is no need for maintenance or replacement.

Next, the motor driver 31 determines whether the feed system 3 is turned off (step S82), and repeatedly executes steps S66 to S80 before the feed system 3 is turned off, so as to continuously build the test friction force model and continue to compare the reference friction force. The model is compared with the test friction model, and the feed system 3 is continuously confirmed to be in a healthy state until the feed system 3 is shut down.

If the difference between the reference friction model and the test friction model is not less than the second threshold value, it means that the status change of the feed system 3/motor 32 since the start/replacement/maintenance has exceeded a tolerable range, so the motor drive 31 It is determined that the feed system 3 is currently in an unhealthy state (step S78), and needs to be maintained or replaced. In addition, in order to remind relevant personnel to maintain or replace the feed system 3 or the motor 32, the motor driver 31 may further issue a warning signal (step S80). In one embodiment, the motor driver 31 can issue a warning signal in the form of text, image, or sound through a display or a buzzer (not shown) on the feeding system 3, or transmit the warning signal to and from the feeder. System 3 displays on an external device connected by wire or wirelessly, and is not limited.

In the above step 72, the motor driver 31 mainly calculates the relative error between the complex model parameters in the reference friction force model and the complex model parameters in the test friction force model to determine the difference between the reference friction force model and the test friction force model. Whether the difference is less than the second threshold value. Wherein, the comparison method adopted in step S72 is similar to the comparison method adopted in step S42 of FIG. 5 described above, and will not be repeated here.

One is worth, in addition to the motor driver 31 can be compared to a plurality of model parameters (e.g. the formula III _{a i, b i, c i} , d) based on the friction model 312, also by the formula The multiple model parameters in Formula One and Formula Two are used to compare the similarity between the reference friction force model and the test friction force model.

As mentioned in the foregoing, the compensation method of the present invention can be mainly through formula one: C _m =J×α+sgn(ω)×f _c +ω×B+C _g and formula two: C _f =C _m -J× α-ω×BC _{g is} used to estimate the friction force of the motor 32 at each rotation position. In this embodiment, the motor driver 31 can simultaneously use the Coulomb friction force f _c , the viscous friction coefficient B and the constant C _g in the above formula as the model parameters, and refer to the Coulomb friction force f in the friction force model. _C, B and viscous friction coefficient constant C _g respectively of Coulomb friction model test friction f _c, viscous frictional coefficient C _g and a constant B for comparison, this way, can make the results more accurate than .

In this embodiment, the motor driver 31 directly determines that the feed system 3 is still in a healthy state when the relative errors of the model parameters of the reference friction model and the test friction model are respectively smaller than the second threshold value. Moreover, when the relative error of one or more model parameters of the motor driver 31 is not less than the second threshold value, it is determined that the feed system 3 is currently in an unhealthy state and needs to be maintained or replaced.

With the above technical solution, the compensation method of the present invention can predict and compensate the friction force of the feed system 3 through the friction force model 312, and use the friction force model 312 to monitor the change of the friction force for a long time, and then evaluate the feed force. The health status of system 3. In this way, the maintenance and replacement of the feed system 3 can be performed effectively and timely, which is quite convenient.

The compensation method of the present invention can be mainly implemented by computer executable program codes and recorded in a computer readable storage medium. In the foregoing embodiment, the computer-readable storage medium is mainly configured in the feeding system 3, and the motor driver 31 of the feeding system 3 directly executes the relevant program codes to execute each step of the compensation method of the present invention.

In other embodiments, the computer-readable storage medium may be configured in an external device such as a controller, a personal computer, a notebook computer, or a server, which is wired or wirelessly connected to the feeding system 3, and is used by these external devices. Relevant program codes are executed instead of the motor driver 31 to execute each step of the compensation method of the present invention.

More specifically, when the motor driver 31, controller, personal computer, notebook computer or server executes the relevant program code recorded in the computer-readable storage medium, at least the feeding system 3 can be controlled to execute the following The steps: (1) Continuously extract the current signal and angular position signal of the motor 32 of the feed system 3 during rotation from the motor driver 31 of the feed system 3; (2) Estimate separately based on the captured current signal and angular position signal The friction force of the motor 32 at each rotation position, and generate multiple friction force data; (3) The calculation is performed based on the estimated friction data and the angular position signal corresponding to each friction force to establish the friction force for the motor 32 Model 312; (4) incorporate the current angular position signal of the motor 32 into the established friction model 312 to predict the predicted friction of the feed system 3; (5) calculate the corresponding compensation current based on the predicted friction; and (6) Control the motor driver 31 to additionally apply the compensation current to the motor 32, so that the motor 32 has sufficient power to overcome the actual friction force in accordance with the prediction.

The above are only preferred specific examples of the present invention, and are not limited to the scope of the patent of the present invention. Therefore, all equivalent changes made by using the content of the present invention are included in the scope of the present invention in the same way, and they are all included in the present invention. Bright.

S10~S26: Compensation steps

Claims (13)

A method for predicting and compensating the friction force of a feeding system is applied to a feeding system. The feeding system has at least one set of mechanical components, a motor that guides the mechanical components to act, and is electrically connected to the motor and controls the motor A motor driver that rotates and includes the following steps: a) The motor driver captures a current signal and a position signal when the motor rotates; b) Estimating a frictional force of the motor based on the current signal and the position signal, And generate a friction force data; c) calculate a formula based on the friction force data and the position signal corresponding to the friction force data to establish a friction force model for the motor, the formula is:

, Where u is a step function, a _i is a first model parameter, b _i is a second model parameter, c _i is a third model parameter, d is a fourth model parameter; d1) the current The position signal is incorporated into the friction force model to predict a predicted friction force of the feed system; e) a corresponding compensation current is calculated based on the predicted friction force; and f) the motor driver is controlled to additionally apply the compensation current to The motor. The friction prediction and compensation method of the feed system according to claim 1, which further includes the following steps: g) after step f, determine whether the feed system is closed; and h) continue before the feed system is closed Perform this step d to this step f. The friction force prediction and compensation method of the feed system according to claim 1, wherein in step a, the motor driver controls the motor to perform a circular motion, and sequentially captures the time when the motor is at each rotation position The current signal and the position signal. The friction force prediction and compensation method of the feed system according to claim 1, wherein the step b is to calculate the friction force of the motor according to a first formula: C _f =C _m -J×α-ω×BC _g , Where C _{f is} the friction force, C _{m is} the current signal, J is a moment of inertia of the motor, α is an angular acceleration of the motor, ω is an angular velocity of the motor, B is a viscous friction coefficient, C _g is a constant. The friction force prediction and compensation method of the feed system as described in claim 4, wherein the step b also executes a second formula: C _m =J×α+sgn( ω )×f _c +ω×B+C _g , Where sgn() represents the forward and reverse information of the motor, f _c is a Coulomb friction force, and the motor driver calculates the angle of the motor according to the position signal and time of the motor at each position in the step b Acceleration and the angular velocity, and estimate the moment of inertia, the viscous friction coefficient, the Coulomb friction and the constant by the least square method. The friction force prediction and compensation method of the feed system according to claim 1, wherein the step c is to perform a curve fitting on the friction forces of the motor at each rotation position based on the third formula Perform operations to obtain the first model parameter, the second model parameter, the third model parameter, and the fourth model parameter, respectively. The friction force prediction and compensation method of the feed system according to claim 1, wherein the friction force model is an estimated friction force model, and the friction force prediction and compensation method further includes the following steps: i) Re-estimate the friction force of the motor based on the current signal and the position signal, and generate the friction force data; j) Perform calculations based on the re-estimated friction force data and the position signal corresponding to each friction force to Establish a second friction force model; k) compare the estimated friction force model with the second friction force model; l) when the difference between the estimated friction force model and the second friction force model is less than a first When the threshold value is used, the second friction force model is discarded; m) when the difference between the estimated friction force model and the second friction force model is not less than the first threshold value, the second friction force model is used to update the estimation A friction force model; and n) before the feed system is closed, execute the step i to the step m again according to the estimated friction force model. The friction force prediction and compensation method of the feed system according to claim 7, wherein the step k is to perform a relative error between the complex model parameter in the estimated friction force model and the complex model parameter in the second friction force model And determine whether the relative error of each model parameter is smaller than the first threshold value. The friction force prediction and compensation method of the feed system according to claim 1, wherein the friction force model is a reference friction force model, and the friction force prediction and compensation method further includes the following steps: o) Determine whether a running time Exceed an inspection period; p) re-execute the step d to the step f before the operation time exceeds the inspection period; q) re-estimate the motor based on the current signal and the position signal after the operation time exceeds the inspection period The friction force of, and generate the friction force data; r) Perform calculations based on the re-estimated friction force data and the position signal corresponding to each friction force to establish a test friction force model; s) compare the reference friction force model with the test friction force model; t ) When the difference between the reference friction force model and the test friction force model is less than a second threshold value, it is determined that the feed system is currently in a healthy state; and u) the difference between the reference friction force model and the test friction force model When the difference is not less than the second threshold value, it is determined that the feeding system is currently in an unhealthy state, and a warning signal is issued. The friction force prediction and compensation method of the feed system according to claim 9, wherein the step s is to calculate the relative error between the complex model parameter in the reference friction force model and the complex model parameter in the test friction force model , And judge whether the relative error of each model parameter is smaller than the second threshold value. According to claim 10, the friction force prediction and compensation method of the feed system, wherein the inspection period is 2 to 4 weeks. A computer-readable storage medium that records a computer-executable program code. After the program code is executed, the following steps are executed: a) A motor driver of a feed system continuously captures a motor of the feed system. A current signal and a position signal during rotation; b) A friction force of the motor is estimated according to the current signal and the position signal, and a friction force data is generated; c) According to the friction force data and the corresponding friction force The position signal calculates a formula to establish a frictional force model for the motor, and the formula is:

, Where u is a step function, a _i is a first model parameter, b _i is a second model parameter, c _i is a third model parameter, d is a fourth model parameter; d) the current The position signal is incorporated into the friction force model to predict a predicted friction force of the feed system; e) calculate a corresponding compensation current based on the predicted friction force; and f) control the motor driver to additionally apply the compensation current to the motor. The computer-readable storage medium according to claim 12, wherein the program code is executed by the motor driver in the feeding system, or by a controller, a personal computer, or a notebook connected to the feeding system Executed by a computer or a server.

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