Motor inertia estimation device, motor drive control device, and motor inertia estimation method

Abstract

To accurately estimate inertia regardless of a magnitude of acceleration / deceleration of a motor.SOLUTION: An inertia estimation device 16 of a motor 2 includes a filter unit 161 that attenuates frequency characteristics of a physical quantity associated with drive of the motor 2, and an inertia estimation unit 162 that estimates inertia of the motor 2 based on the attenuated physical quantity. In a motor drive control device 1, a drive control unit 12 that controls drive of the motor 2 according to command information related to rotation speed of the motor 2 controls the drive of the motor 2 according to the inertia.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a motor inertia estimation device, a motor drive control device, and a motor inertia estimation method. [Background technology]

[0002] In motor drive control, it is known to estimate inertia and reflect the estimated inertia value in gain adjustment (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-313495 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in motor drive control, if inertia is estimated when the acceleration / deceleration of the motor is small, the noise component in the estimated inertia becomes large, resulting in a large error, i.e., the accuracy of the estimation deteriorates, which is a problem.

[0005] The present invention addresses the above-mentioned problem as an example, and aims to provide a technique for estimating inertia with high accuracy regardless of the magnitude of the acceleration / deceleration of the motor. [Means for solving the problem]

[0006] In order to achieve the above object, the motor inertia estimating device according to the present invention includes a filter unit that attenuates the frequency characteristics of a physical quantity associated with driving of a motor, and an inertia estimating unit that estimates the inertia of the motor based on the attenuated physical quantity. [Effects of the Invention]

[0007] According to the motor inertia estimation device of the present invention, the inertia can be estimated with high accuracy regardless of the magnitude of the acceleration / deceleration of the motor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a functional block diagram illustrating a schematic configuration of a motor drive control device including a motor inertia estimation processing unit according to a first embodiment of the present invention. [Figure 2] 4 is a graph showing an example of a change in the rotation speed of a motor caused by the motor drive control device according to the embodiment. [Figure 3] 4 is a flowchart showing the flow of processing by the motor drive control device according to the first embodiment. [Figure 4] 10 is a graph showing an example of the relationship between the rotation speed of a motor and the amount of inertia estimated by the motor inertia estimation device of the reference example. [Figure 5] 4 is a graph showing an example of the relationship between the rotation speed of a motor and the amount of inertia estimated by the motor inertia estimation device according to the embodiment. [Figure 6] FIG. 6 is a functional block diagram illustrating the schematic configuration of a motor drive control device including a motor inertia estimation device according to a second embodiment of the present invention. [Figure 7] 10 is a flowchart showing a flow of processing by a motor drive control device according to a second embodiment. [Figure 8] FIG. 10 is a functional block diagram illustrating the schematic configuration of a motor drive control device including a motor inertia estimation device according to a third embodiment of the present invention. [Figure 9] 10 is a flowchart showing a flow of processing by a motor drive control device according to a third embodiment. [Figure 10] 10 is a graph showing an example of a change in rotation speed when the amount of movement of the motor caused by the motor drive control device according to the third embodiment is small. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a motor inertia estimation device, a motor drive control device, and a motor inertia estimation method according to embodiments of the present invention will be described with reference to the drawings. In the following description, components common to each embodiment will be designated by the same reference numerals, and repeated description will be omitted.

[0010] [First embodiment] FIG. 1 is a functional block diagram showing a schematic configuration of a motor drive control device 1 including an inertia estimation processing unit 16 for a motor 2 according to a first embodiment of the present invention.

[0011] The motor 2 is a permanent magnet motor. In this embodiment, the motor 2 is, for example, a stepping motor having two-phase (A-phase and B-phase) coils.

[0012] The motor drive control device 1, for example, periodically applies a drive current to the A-phase and B-phase coils of the motor 2, causing the rotor (permanent magnet) of the motor 2 to rotate.

[0013] As shown in FIG. 1, the motor drive control device 1 includes, as functional blocks, a command generation unit 11, a drive control unit 12, a current detection unit 13, a position detection unit 14, a speed calculation unit 15, and an inertia estimation processing unit 16.

[0014] In this embodiment, the motor drive control device 1 is a program processing device (e.g., a microcontroller) having a configuration in which a processor such as a CPU, various storage devices such as RAM and ROM, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output I / F circuit are connected to each other via a bus or dedicated lines.

[0015] The motor drive control device 1 may be configured as a single packaged integrated circuit device (IC), or may be configured as a collection of multiple integrated circuit devices that each realize some of the functional blocks and are each packaged.

[0016] The functional blocks of the motor drive control device 1 are realized, for example, by a processor in a program processing device serving as a control circuit, which executes various arithmetic operations in accordance with programs stored in memory and controls peripheral circuits such as counters and A / D conversion circuits.

[0017] Note that the components of the motor drive control device 1 shown in FIG. 1 are only a part of the whole, and the motor drive control device 1 may have other components in addition to those shown in FIG.

[0018] The command generation unit 11 receives a speed command signal Sc, which is command information related to the rotational speed of the motor 2, and analyzes the received speed command signal Sc to generate a value specifying a target operating state of the motor 2 specified by the speed command signal Sc. The operating state refers to the state of the motor 2 rotating at the speed specified by the speed command signal Sc. The command generation unit 11 outputs the generated value specifying the target operating state of the motor 2 as a trapezoidal speed command to the drive control unit 12. The command generation unit 11 outputs the acceleration / deceleration time Tc included in the value specifying the target operating state of the motor 2 to the frequency determination unit 163. The speed command signal Sc is output, for example, from a higher-level device for controlling the motor 2, which is provided outside the motor drive control device 1.

[0019] The speed command signal Sc includes a value that instructs the motor 2 to reach a target operating state. The speed command signal Sc is, for example, a signal that includes command information that commands the rotational speed of the rotor of the motor 2. The speed command signal Sc includes a target value (target rotational speed) for the rotational speed of the rotor of the motor 2 and an acceleration / deceleration time Tc.

[0020] FIG. 2 is a graph showing an example of changes in the rotation speed of the motor 2 caused by the motor drive control device 1.

[0021] In this embodiment, the speed command signal Sc is a signal for realizing a trapezoidal speed command that performs control in the shortest time while using the maximum output of the motor 2. By using the trapezoidal speed command, for example, the speed of the motor 2 increases from the minimum speed Vf to the maximum speed Vm at the maximum acceleration A. After the speed of the motor 2 increases to the maximum speed Vm, the motor 2 moves at the maximum speed Vm and then decelerates to the target minimum speed Vf at the maximum deceleration -A.

[0022] The drive control unit 12 generates a drive control signal Sd for controlling the drive of the motor 2 in accordance with the trapezoidal speed command output by the command generation unit 11 and the rotational speed ω of the rotor of the motor 2 calculated by the speed calculation unit 15. For example, the drive control signal Sd is a target value of the current of the motor 2, which is generated in accordance with the trapezoidal speed command and the rotational speed ω. The drive control unit 12 generates the drive control signal Sd by performing, for example, a calculation related to speed control in accordance with the trapezoidal speed command and the rotational speed ω. Specifically, the drive control unit 12 calculates a control amount in accordance with the difference Δ between the speed command signal Sc included in the trapezoidal speed command and the rotational speed ω. For example, the drive control unit 12 calculates the drive control signal Sd for the motor 2 by a PI control calculation so that the difference Δ becomes zero. The drive control unit 12 corrects the value of the drive control signal Sd for controlling the drive of the motor 2 based on a parameter vector calculated in accordance with the inertia estimated by the inertia estimation processing unit 16, which will be described later.

[0023] The current detection unit 13 is a functional unit for detecting the drive current I of the coil of each phase of the motor 2 and outputting the detected value to the filter unit 161. The current detection unit 13 is an example of a detection unit that detects a physical quantity associated with driving. The current detection unit 13 is, for example, a shunt resistor connected in series with an inverter circuit between a DC power supply and a ground potential.

[0024] The position detection unit 14 is a functional unit for detecting the rotational position of the rotor of the motor 2. The position detection unit 14 is an example of a detection unit that detects a physical quantity associated with driving, and is, for example, an encoder. The position detection unit 14 outputs a detection value corresponding to the rotational position of the rotor of the motor 2 to the speed calculation unit 15. Note that the position detection unit 14 is not limited to an encoder, and may be a Hall element or the like.

[0025] The speed calculation unit 15 is a functional unit that acquires a measured value of the rotation speed of the rotor of the motor 2. The speed calculation unit 15 calculates the rotation speed ω of the rotor of the motor 2 based on, for example, the detected value of the rotation position output from the position detection unit 14.

[0026] The inertia estimation processing unit 16 is a functional block realized inside the motor drive control device 1, and functions as the inertia estimation device of the present invention. The inertia estimation processing unit 16 is composed of a filter unit 161, an inertia estimation unit 162, and a frequency determination unit 163.

[0027] The filter unit 161 attenuates the frequency characteristics of the detected physical quantities, i.e., the rotation speed ω of the rotor of the motor 2 and the coil drive current I. The filter unit 161 is a low-pass filter that attenuates the frequency characteristics of the rotation speed ω and the drive current I that are equal to or lower than the cutoff frequency fc, in accordance with the cutoff frequency fc determined by the frequency determination unit 163.

[0028] The filter unit 161 may attenuate the frequency characteristics equal to or lower than the cutoff frequency fc for the value of the torque T of the motor 2, instead of the coil drive current I. In this case, the filter unit 161 calculates the torque T of the motor 2 from the drive current I, drive voltage, and rotation speed ω of the motor 2.

[0029] The frequency determination unit 163 determines the cutoff frequency fc of the physical quantity based on the acceleration / deceleration time Tc included in the speed command signal Sc. The acceleration / deceleration time Tc refers to the time required for the speed of the motor 2 to increase from the minimum speed Vf to the maximum speed Vm at the maximum acceleration A, and the time required for the speed of the motor 2 to decelerate from the maximum speed Vm to the target minimum speed Vf at the maximum deceleration -A, both of which are included in the above-mentioned speed command signal Sc. The frequency determination unit 163 calculates the cutoff frequency fc from the acceleration / deceleration time Tc using the following equation (1). In equation (1), N is a constant.

[0030] fc=N×1 / Tc (1)

[0031] The inertia estimation unit 162 estimates the inertia of the motor based on the damped rotation speed ω and the frequency characteristics of the coil drive current I. The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12. The parameter vector can be calculated using the recursive least squares method according to the following equations (2) and (3). In equations (2) and (3), the inertia is JPEG2025140051000002.jpg10127. In addition, in equations (2) and (3), the parameter vector is Let's set the file name to JPEG2025140051000003.jpg6127.

[0032] JPEG2025140051000004.jpg12169

[0033] JPEG2025140051000005.jpg16169

[0034] In equation (2), G n and e n can be calculated using the following equations (4) and (5). In equations (3) to (5), the rotation speed ω is JPEG2025140051000006.jpg10169, and the current I is JPEG2025140051000007.jpg8169, respectively. In equations (3) to (5), λ is the forgetting factor.

[0035] JPEG2025140051000008.jpg13169

[0036] JPEG2025140051000009.jpg13169

[0037] The inertia estimation unit 162 outputs to the drive control unit 12 a parameter vector used to correct the calculated value of the drive control signal Sd.

[0038] FIG. 3 is a flowchart showing the flow of processing by the motor drive control device 1 according to the first embodiment.

[0039] In the motor drive control device 1, the command generating unit 11 outputs a value that specifies a target operating state of the motor 2, generated in response to the speed command signal Sc, to the drive control unit 12 as a trapezoidal speed command (step S101).

[0040] The command generating unit 11 outputs the acceleration / deceleration time Tc to the frequency determining unit 163 (step S102).

[0041] The frequency determination unit 163 determines the cutoff frequency fc of the physical quantity based on the acceleration / deceleration time Tc included in the speed command signal Sc (step S103).

[0042] The filter unit 161 sets the cutoff frequency fc determined by the frequency determination unit 163 (step S104).

[0043] The drive control unit 12 generates a drive control signal Sd that controls the drive of the motor 2 in accordance with the trapezoidal speed command output by the command generation unit 11 and the rotational speed ω of the rotor of the motor 2 calculated by the speed calculation unit 15, and outputs the signal to the motor 2 to drive the motor 2 (step S105).

[0044] The current detection unit 13 detects the coil drive current I output from the drive control unit 12 to the motor 2 (step S106). The detected drive current I is output to the filter unit 161.

[0045] The filter unit 161 performs filtering to attenuate the frequency characteristics of the rotation speed ω and the driving current I that are equal to or lower than the cutoff frequency fc in accordance with the cutoff frequency fc (step S107).

[0046] The inertia estimation unit 162 estimates the inertia of the motor based on the attenuated rotational speed ω and the frequency characteristics of the coil drive current I (step S108). The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12, and outputs the parameter vector to the drive control unit 12. The drive control unit 12 corrects the value of the drive control signal Sd using the parameter vector.

[0047] As described above, the motor drive control device 1 according to this embodiment includes an inertia estimation processing unit 16 that includes a filter unit 161 that attenuates the frequency characteristics of a physical quantity (at least one of the rotational speed ω, drive current I, and torque T) associated with the driving of the motor 2, and an inertia estimation unit 162 that estimates the inertia of the motor 2 based on the attenuated physical quantity. For example, the filter unit 161 is a low-pass filter that attenuates the frequency characteristics of the physical quantity corresponding to a cutoff frequency fc. The cutoff frequency fc is determined by a frequency determination unit 163, for example, based on command information related to the rotational speed ω of the motor 2, for example, a trapezoidal speed command included in a speed command signal Sc.

[0048] Fig. 4 is a graph showing an example of the relationship between the rotation speed ω of the motor 2 and the amount of inertia estimated by the inertia estimation device of the motor 2 of the reference example. Fig. 5 is a graph showing an example of the relationship between the rotation speed ω of the motor 2 and the amount of inertia estimated by the inertia estimation processing unit 16 of the motor 2. The inertia estimation device of the reference example that performs the processing shown in Fig. 4 differs from the inertia estimation processing unit 16 in that it does not have a frequency determination unit 163 that determines the cutoff frequency fc of the physical quantity based on the acceleration / deceleration time Tc. Figs. 4 and 5 show changes in the estimated amount of inertia due to changes in the rotation speed ω of the rotor of the motor 2.

[0049] According to FIG. 5, it can be seen that the inertia estimated by the inertia estimation processing unit 16 has less change in value between the region where the change in rotational speed ω is small, i.e., the region where the acceleration / deceleration A is small, and other regions, compared to the inertia estimated by the inertia estimation device of the reference example shown in FIG.

[0050] Therefore, the inertia estimation processing unit 16 that executes the inertia estimation method shown in the flowchart of Figure 3 and the motor drive control device 1 that is equipped with the inertia estimation processing unit 16 can accurately estimate inertia regardless of the magnitude of the acceleration / deceleration A of the motor 2.

[0051] The frequency determination unit 163 determines the cutoff frequency fc in accordance with the acceleration / deceleration time Tc of the motor 2, and therefore the inertia estimation processing unit 16 and the motor drive control device 1 can accurately estimate the inertia regardless of the magnitude of the acceleration / deceleration A of the motor 2.

[0052] [Second embodiment] A specific example of the second embodiment of the present invention will be described below with reference to the drawings.

[0053] The second embodiment relates to another function realized in the motor drive control device 1 previously described and shown in Fig. 1. Therefore, in the following description, the components of the motor drive control device 1 that are common to the first embodiment are given the same reference numerals, and repeated description will be omitted.

[0054] The specific configuration and operation of the motor drive control device 1 according to the second embodiment will be described in detail below.

[0055] FIG. 6 is a functional block diagram showing a schematic configuration of a motor drive control device 1 including an inertia estimation processing unit 16B for a motor 2 according to a second embodiment of the present invention.

[0056] As shown in FIG. 6, the motor drive control device 1 according to the second embodiment has an inertia estimation processing unit 16B configured differently from the inertia estimation processing unit 16 of the motor drive control device 1 according to the first embodiment described above.

[0057] The inertia estimation processing unit 16B is made up of a filter unit 161B and an inertia estimation unit 162. Unlike the inertia estimation processing unit 16, the inertia estimation processing unit 16B does not have a frequency determination unit 163.

[0058] Similar to the filter unit 161 in the inertia estimation processing unit 16 described above, the filter unit 161B attenuates the frequency characteristics of the detected physical quantities, i.e., the rotational speed ω of the rotor of the motor 2 and the driving current I of the coil. The filter unit 161B is a notch filter that attenuates the frequency characteristics corresponding to a frequency band fb included in the rotational speed ω and the driving current I in accordance with a predetermined frequency band fb. The frequency band fb attenuated by the filter unit 161B can be identified, for example, by analyzing, using FFT (Fast Fourier transform), the waveform of vibration measured when vibration occurs when the motor 2 is driven by the motor drive control device 1 (rotational speed, rotational position, acceleration / deceleration, etc.). Alternatively, a vibration detection unit may be provided in the motor drive control device 1, and the filter unit 161B may be activated when vibration is detected while the motor 2 is being driven.

[0059] Similar to the inertia estimation processing unit 16 described above, the inertia estimation unit 162 estimates the inertia of the motor based on the attenuated rotational speed ω and the frequency characteristics of the coil drive current I. The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12.

[0060] FIG. 7 is a flowchart showing the flow of processing by the motor drive control device 1 according to the second embodiment.

[0061] In the motor drive control device 1, the command generating unit 11 outputs a value that specifies a target operating state of the motor 2, generated in response to the speed command signal Sc, to the drive control unit 12 as a trapezoidal speed command (step S201).

[0062] The drive control unit 12 generates a drive control signal Sd for controlling the drive of the motor 2 in accordance with the trapezoidal speed command output by the command generation unit 11 and the rotational speed ω of the rotor of the motor 2 calculated by the speed calculation unit 15, and outputs the signal to the motor 2 to drive the motor 2 (step S202).

[0063] The current detection unit 13 detects the coil drive current I output from the drive control unit 12 to the motor 2 (step S203). The detected drive current I is output to the filter unit 161.

[0064] The position detector 14 detects the rotational position (angle) of the rotor of the motor 2 (step S204). The position detector 14 outputs a detection value of the rotational position corresponding to the rotational position of the rotor of the motor 2.

[0065] The speed calculation unit 15 calculates the rotation speed ω of the rotor of the motor 2 based on, for example, the detected value of the rotation position output from the position detection unit 14 (step S205).

[0066] The filter unit 161B performs filtering corresponding to the frequency band fb to attenuate the frequency characteristics of the rotation speed ω and the frequency band fb included in the driving current I (step S206).

[0067] The inertia estimation unit 162 estimates the inertia of the motor based on the attenuated rotational speed ω and the frequency characteristics of the coil drive current I (step S207). The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12, and outputs the parameter vector to the drive control unit 12. The drive control unit 12 corrects the value of the drive control signal Sd using the parameter vector.

[0068] As described above, the motor drive control device 1 according to this embodiment includes an inertia estimation processing unit 16B that includes a filter unit 161B that attenuates the frequency characteristics of a physical quantity (at least one of the rotational speed ω, drive current I, and torque T) associated with the driving of the motor 2, and an inertia estimation unit 162 that estimates the inertia of the motor 2 based on the attenuated physical quantity. The filter unit 161B is a notch filter that attenuates the frequency characteristics of the physical quantity corresponding to a predetermined frequency band fb. The frequency band fb is based on, for example, a trapezoidal speed command included in the speed command signal Sc.

[0069] As shown in FIG. 5, in the inertia estimation processing unit 16B, the estimated inertia also changes less between the region where the change in rotation speed ω is small, i.e., the region where the acceleration / deceleration A is small, and other regions, compared to the inertia estimated by the inertia estimation device of the reference example shown in FIG. 4.

[0070] Therefore, the inertia estimation processing unit 16B that executes the inertia estimation method shown in the flowchart of Figure 7 and the motor drive control device 1 equipped with the inertia estimation processing unit 16B can accurately estimate inertia regardless of the magnitude of the acceleration / deceleration A of the motor 2.

[0071] [Third embodiment] A specific example of the third embodiment of the present invention will be described below with reference to the drawings.

[0072] The third embodiment relates to another function realized in the motor drive control device 1 previously described and shown in Fig. 1. Therefore, in the following description, the components of the motor drive control device 1 that are common to the first embodiment are given the same reference numerals, and repeated description will be omitted.

[0073] The specific configuration and operation of the motor drive control device 1 according to the third embodiment will be described in detail below.

[0074] As shown in FIG. 8, the motor drive control device 1 according to the third embodiment has an inertia estimation processing unit 16C whose configuration differs from that of the inertia estimation processing unit 16 of the motor drive control device 1 according to the first embodiment described above.

[0075] The inertia estimation processing unit 16C is made up of a filter unit 161, an inertia estimation unit 162, and a frequency determination unit 163C.

[0076] The frequency determination unit 163C determines the cutoff frequency fc of the physical quantity based on the maximum speed Vm and minimum speed Vf of the motor 2 realized by the speed command signal Sc as described above, and the movement amount (rotation amount) L calculated from the rotation speed of the motor 2 included in the speed command signal Sc and the acceleration / deceleration time Tc. Specifically, the frequency determination unit 163C determines whether the movement amount L satisfies the condition of the following equation (6). Equation (6) determines whether the speed of the motor 2 has not reached the maximum speed Vm. If the condition of equation (6) is satisfied, the frequency determination unit 163C calculates the maximum speed Vm using the following equation (7).

[0077] L≦1 / 2*(Vm+Vf)*((Vm-A) / A)···(6)

[0078] Vm=(2*L*A+Vf 2 ) 1 / 2 ···(7)

[0079] When the condition of equation (6) is satisfied, the frequency determination unit 163C determines the cutoff frequency fc of the physical quantity from the following equation (8) using the maximum speed Vm calculated by equation (7), the acceleration A, and the constant N. Furthermore, when the condition of equation (6) is not satisfied, that is, when the speed of the motor 2 reaches the maximum speed Vm, the frequency determination unit 163C determines the cutoff frequency fc of the physical quantity from the following equation (9) using the maximum speed Vm, the acceleration A, and the constant N acquired from the command generation unit 11. In equations (8) and (9), N is a constant greater than or equal to 1.

[0080] fc=(Vm / A)*N (8)

[0081] fc=1 / (Vm / A)*N (9)

[0082] Similar to the filter unit 161 in the inertia estimation processing unit 16 described above, the filter unit 161 is a low-pass filter that attenuates the frequency characteristics of the rotation speed ω and the drive current I that are equal to or lower than the cutoff frequency fc, in accordance with the cutoff frequency fc determined by the frequency determination unit 163C.

[0083] Similar to the inertia estimation processing unit 16 described above, the inertia estimation unit 162 estimates the inertia of the motor based on the attenuated rotational speed ω and the frequency characteristics of the coil drive current I. The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12.

[0084] FIG. 9 is a flowchart showing the flow of processing by the motor drive control device 1 according to the third embodiment.

[0085] In the motor drive control device 1, the command generating unit 11 outputs a value that specifies a target operating state of the motor 2, generated in response to the speed command signal Sc, to the drive control unit 12 as a trapezoidal speed command (step S301).

[0086] The command generating unit 11 outputs the maximum speed Vm, minimum speed Vf, and movement amount (rotation amount) L of the motor 2 included in the speed command signal Sc to the frequency determining unit 163 (step S302).

[0087] The frequency determination unit 163C determines whether the movement amount L does not reach the maximum speed Vm of the motor 2 according to equation (6) based on the maximum speed Vm, minimum speed Vf, and movement amount (rotation amount) L of the motor 2 contained in the speed command signal Sc (step S303).

[0088] If the maximum speed Vm of the motor 2 has not been reached (S303: YES), the frequency determination unit 163C calculates the maximum speed Vm using equation (7), and determines the cutoff frequency fc of the physical quantity from equation (8) using the maximum speed Vm calculated using equation (7), the acceleration A, and the constant N (step S304).

[0089] When the speed of the motor 2 reaches the maximum speed Vm (S303: NO), the frequency determination unit 163C determines the cutoff frequency fc of the physical quantity from the following equation (9) using the maximum speed Vm, acceleration A, and constant N obtained from the command generation unit 11 (step S305).

[0090] The filter unit 161 sets the cutoff frequency fc determined by the frequency determination unit 163 (step S306).

[0091] The drive control unit 12 generates a drive control signal Sd that controls the drive of the motor 2 in accordance with the trapezoidal speed command output by the command generation unit 11 and the rotational speed ω of the rotor of the motor 2 calculated by the speed calculation unit 15, and outputs the signal to the motor 2 to drive the motor 2 (step S307).

[0092] The current detection unit 13 detects the coil drive current I output from the drive control unit 12 to the motor 2 (step S308). The detected drive current I is output to the filter unit 161.

[0093] The position detector 14 detects the rotational position (angle) of the rotor of the motor 2 (step S309). The position detector 14 outputs a detection value of the rotational position corresponding to the rotational position of the rotor of the motor 2.

[0094] The speed calculation unit 15 calculates the rotation speed ω of the rotor of the motor 2 based on, for example, the detected value of the rotation position output from the position detection unit 14 (step S310).

[0095] The filter unit 161B performs filtering to attenuate the frequency characteristics of the rotation speed ω and the frequency band fb included in the drive current I in accordance with the cutoff frequency fc (step S311).

[0096] The inertia estimation unit 162 estimates the inertia of the motor based on the damped rotational speed ω and the frequency characteristics of the coil drive current I (step S312). The inertia estimation unit 162 estimates the inertia and calculates a parameter vector used to correct the value of the drive control signal Sd generated by the drive control unit 12, and outputs the parameter vector to the drive control unit 12. The drive control unit 12 corrects the value of the drive control signal Sd using the parameter vector.

[0097] As described above, the motor drive control device 1 according to this embodiment includes an inertia estimation processing unit 16C including a filter unit 161 that attenuates the frequency characteristics of a physical quantity (at least one of the rotational speed ω, drive current I, and torque T) associated with the driving of the motor 2, an inertia estimation unit 162 that estimates the inertia of the motor 2 based on the attenuated physical quantity, and a frequency determination unit 163C that determines a cutoff frequency fc based on command information related to the rotational speed ω of the motor 2, such as a trapezoidal speed command included in a speed command signal Sc. The filter unit 161 is a low-pass filter that attenuates the frequency characteristics of the physical quantity corresponding to the cutoff frequency fc. The cutoff frequency fc is determined by the frequency determination unit 163C, for example, in accordance with information included in the trapezoidal speed command, such as the rotation amount L of the motor 2. Specifically, to determine the cutoff frequency fc, the frequency determination unit 163C determines whether the movement amount (rotation amount) L satisfies a condition determined by the maximum speed Vm and the minimum speed Vf, and changes the equation for calculating the cutoff frequency fc depending on the determination result.

[0098] As shown in FIG. 5, in the inertia estimation processing unit 16C, the estimated inertia also changes less between the region where the change in rotational speed ω is small, i.e., the region where the acceleration / deceleration A is small, and other regions, compared to the inertia estimated by the inertia estimation device of the reference example shown in FIG. 4.

[0099] FIG. 10 is a graph showing an example of changes in rotation speed ω when the movement amount L of motor 2 caused by motor drive control device 1 is small.

[0100] 10, when the movement amount L of the motor 2 is small, the movement amount L is reached before the maximum speed Vm included in the trapezoidal speed command is reached. In such a case, if the cutoff frequency fc is set according to the acceleration / deceleration time Tc, the cutoff frequency fc becomes small, and it is conceivable that the signal of the physical quantity will be attenuated more than necessary by filtering by the filter unit 161.

[0101] Therefore, the frequency determination unit 163C of the inertia estimation processing unit 16C determines whether the movement amount L satisfies the condition determined by the maximum speed Vm and the minimum speed Vf, and changes the formula for calculating the cutoff frequency fc according to the determination result.

[0102] Therefore, the inertia estimation processing unit 16C that executes the inertia estimation method shown in the flowchart of Figure 9 and the motor drive control device 1 equipped with the inertia estimation processing unit 16C can accurately estimate inertia regardless of the magnitude of the acceleration / deceleration speed A or the movement amount L of the motor 2.

[0103] In the above embodiment, the inertia estimation processing unit 16 has been described in detail as a functional block built into the motor drive control device 1. However, the inertia estimation device of the present invention may be configured as an external device communicatively connected to the motor drive control device 1, which realizes the functions of the inertia estimation processing units 16, 16B, and 16C described above. In this case, the inertia estimation device is, for example, a program processing device (e.g., a microcontroller) having a configuration in which a processor such as a CPU, various storage devices such as RAM and ROM, and peripheral circuits such as a counter (timer), an A / D conversion circuit, a D / A conversion circuit, a clock generation circuit, and an input / output I / F circuit are connected to each other via a bus or dedicated lines. Furthermore, the functional blocks of the inertia estimation device are realized, for example, by a program processing device serving as a control circuit, in which a processor executes various arithmetic processes in accordance with programs stored in memory and controls peripheral circuits such as the counter and the A / D conversion circuit.

[0104] In addition, those skilled in the art can appropriately modify the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the structure of the present invention, they are of course included in the scope of the present invention. [Explanation of symbols]

[0105] 1...motor drive control device, 2...motor, 11...command generation unit, 12...drive control unit, 13...current detection unit, 14...position detection unit, 15...speed calculation unit, 16, 16B, 16C...inertia estimation processing unit (inertia estimation device), 161, 161B...filter unit, 162...inertia estimation unit, 163, 163C...frequency determination unit, A: acceleration, fb: frequency band, fc: cutoff frequency, Tc: acceleration / deceleration time, Vf: minimum speed, Vm: maximum speed

Claims

1. a filter unit that attenuates the frequency characteristics of a physical quantity associated with the driving of the motor; an inertia estimation unit that estimates the inertia of the motor based on the damped physical quantity; Equipped with Motor inertia estimation device.

2. The physical quantity is at least one of a rotation speed, a drive current, and a torque of the motor.

2. The motor inertia estimation device according to claim 1.

3. the filter unit is a notch filter that attenuates the frequency characteristics of the physical quantity corresponding to a predetermined frequency band.

3. The motor inertia estimation device according to claim 1 or 2.

4. a frequency determination unit that determines a cutoff frequency of the physical quantity based on command information related to the rotational speed of the motor; the filter unit is a low-pass filter that attenuates the frequency characteristic of the physical quantity corresponding to the cutoff frequency.

3. The motor inertia estimation device according to claim 1 or 2.

5. the frequency determination unit determines the cutoff frequency in accordance with an acceleration / deceleration time of the motor obtained based on the command information.

5. The motor inertia estimation device according to claim 4.

6. the frequency determination unit determines the cutoff frequency in accordance with the rotation amount of the motor obtained based on the command information.

5. The motor inertia estimation device according to claim 4.

7. a drive control unit that controls the drive of the motor in accordance with command information related to the rotation speed of the motor; a detection unit that detects a physical quantity associated with the driving; a filter unit that attenuates the frequency characteristics of the detected physical quantity; an inertia estimation unit that estimates the inertia of the motor based on the damped physical quantity; Equipped with the drive control unit controls the drive of the motor in accordance with the inertia. Motor drive control device.

8. detecting a physical quantity associated with driving of the motor; attenuating the frequency characteristics of the detected physical quantity; estimating the inertia of the motor based on the damped physical quantity; To execute A method for estimating motor inertia.

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