JP2012007334A - Motor torque control device of work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve control stability by decreasing control gain in a speed range affected by back lash of gear mechanism, and to prevent reduction of responsiveness using proper control gain in a speed range not affected by back lash of gear mechanism.SOLUTION: The motor torque control device 10 of the embodiment of the present invention is provided with control gain correction means 18 for correcting a control gain G1 used for the calculation of a torque instruction Trd. The control gain correction means 18 includes a speed threshold value ωd0 defining the upper limit of speed range affected by backlash of a speed reducer 8 occurs, and corrects and reduces the control gain G1 when a speed instruction ωd is less than the speed threshold value ωd0.

Description

  The present invention relates to a motor torque control device for a work machine such as a hydraulic excavator that operates an operating body based on torque control of an electric motor (including a motor and a motor generator functioning as a generator).

  In recent years, also in work machines such as hydraulic excavators, in order to achieve energy saving and exhaust gas reduction, an electric system using an electric power device such as an electric motor as a power source, or a hybrid using both an engine and an electric power device The system is being adopted. For example, as one of the working machines adopting such an electric system or a hybrid system, an upper swing body (actuating body) that is swingably provided on a lower traveling body is driven to rotate by an electric motor. It is known (see, for example, Patent Document 1).

  Such a working machine is provided with an electric motor torque control device that performs torque control of the electric motor. For example, as shown in FIG. 11, the conventional motor torque control apparatus 100 includes a speed command calculation means 103 that calculates a speed command ωd based on an operation position of an operation lever 102 that turns the upper swing body 101, and an upper swing. Speed feedback signal reading means 104 for reading the speed feedback signal ω of the body 101, speed deviation calculating means 105 for calculating the speed deviation Δω between the speed command ωd and the speed feedback signal ω, and the torque of the motor 106 based on the speed deviation Δω. Torque command calculation means 107 for calculating the command Trd is provided.

JP 2005-273262 A

  As shown in FIG. 12, the control gain G1 that determines the ratio of the torque command Trd to the speed deviation Δω is used for the calculation of the torque command Trd. The optimum value of the control gain G1 is a value that can achieve both control stability and responsiveness. In general, the maximum gain value is used within a range of gain values that can ensure control stability. . That is, in a system with high control stability, the control gain G1 can be increased to obtain a good response. However, in a system with low control stability, the control gain G1 can be set at the expense of response. It was necessary to make it smaller.

  In particular, in a work machine in which an operating body is linked to an electric motor via a gear mechanism (for example, a gear-type speed reducer 108), backlash existing in the gear mechanism becomes an unstable element of control, and the control gain cannot be increased. There was a problem. That is, the backlash of the gear mechanism increases the minute command response of the electric motor and may cause unstable events such as hunting. In order to prevent this and increase the stability of the control, it is necessary to reduce the value of the control gain, so even in a load situation where a large torque is required, a sufficient torque cannot be generated, and the response There was a problem that the performance decreased.

  In Patent Document 1, the control gain is set to a predetermined value or less at the time of start-up (the turning body detection speed is equal to or less than the set value) or when pressed (the deviation between the turning body speed command and the turning body detection speed is equal to or more than the set value). Although shown, there is no mention of the relationship with the backlash existing in the gear mechanism and the improvement in response when the load is large. Further, in Patent Document 1, since the turning body detection speed is used as a control gain correction condition, it is difficult to grasp the fluctuation in the speed of the motor caused by the backlash of the gear mechanism and reflect it in the control. Moreover, in Patent Document 1, when the deviation between the swing body speed command and the swing body detection speed is equal to or greater than a set value, the control gain is set to a predetermined value or less, so that the control gain decreases in a situation where the operator expects a high response, It can be counterproductive.

The present invention has been created in order to solve these problems in view of the above circumstances, and an operating body is connected to an electric motor through a gear mechanism, and the above-described operation is performed based on torque control of the electric motor. An electric motor torque control device for a work machine that operates an operating body, wherein the electric motor torque control device calculates a speed command based on an operation position of an operating tool that operates the operating body, and the electric motor And / or speed feedback signal reading means for reading the speed feedback signal of the operating body, speed deviation calculating means for calculating a speed deviation between the speed command and the speed feedback signal, and torque of the electric motor based on the speed deviation A torque command calculating means for calculating a command, and a control gain correcting means for correcting a control gain used for calculating the torque command. The control gain correction means includes a speed threshold value that determines an upper limit of a speed range in which the backlash of the gear mechanism affects, and when the speed command or the speed feedback signal of the motor is equal to or lower than the speed threshold value, The gain is corrected to the decreasing side.
The control gain correction means corrects the control gain to an increase side when the speed command or the speed feedback signal of the electric motor exceeds the speed threshold value.
The control gain correction means has a correction calculation pattern for changing a correction value multiplied by the control gain in accordance with the speed command or a speed feedback signal of the electric motor, and the correction value in the correction calculation pattern A maximum speed and a minimum value are determined, and a second speed threshold value greater than the speed threshold value is provided, and when the speed command or the speed feedback signal of the motor is equal to or less than the speed threshold value, the control is performed using the minimum value When the gain is corrected to the decrease side and the speed command or the speed feedback signal of the electric motor exceeds the second speed threshold, the control gain is corrected to the increase side using the maximum value, and the speed When the command or the speed feedback signal of the motor exceeds the speed threshold and is equal to or less than the second speed threshold, the speed command or Using the correction value proportional to the speed feedback signal of the serial motor and correcting the reduction side or the increase side the control gain.
The control gain correction means determines whether the vehicle is accelerating or decelerating based on a comparison between the speed command and the speed feedback signal, and uses different correction calculation patterns for acceleration and deceleration. The control gain is corrected.

According to the first aspect of the present invention, a speed threshold value that determines an upper limit of the speed range in which the backlash of the gear mechanism affects is provided, and when the speed command or the speed feedback signal of the motor is equal to or lower than the speed threshold value, the control gain is decreased. Since the correction is made, the control gain can be reduced to improve the control stability in the speed range where the gear mechanism backlash is affected, while in the speed range where the gear mechanism is not affected by the backlash, By using the control gain, it is possible to prevent a decrease in responsiveness. In particular, when the control gain is corrected according to the speed command, in a situation where the operator expects a high response (the speed command is large), the control operation against the operator's intention is surely corrected. Can be prevented. Also, when the control gain is corrected according to the speed feedback signal of the electric motor, the speed fluctuation caused by the backlash of the gear mechanism is clearly grasped and reflected in the control, compared with the case where the speed feedback signal of the operating body is used. be able to.
According to the invention of claim 2, when the speed command or the speed feedback signal of the motor exceeds the speed threshold value, the control gain is corrected to the increase side. Therefore, in the speed range where the backlash of the gear mechanism does not affect, By applying a control gain as large as possible, it is possible to show a good response even under a heavy load condition.
According to the invention of claim 3, since the control gain can be prevented from changing suddenly between the speed range in which the control gain is corrected to the decreasing side and the speed range in which the control gain is corrected to the increasing side. Thus, it is possible to avoid the occurrence of speed fluctuations and impacts due to a sudden change in control gain.
According to the invention of claim 4, it is determined whether the vehicle is accelerating or decelerating based on the comparison between the speed command and the speed feedback signal, and different correction calculation patterns are used for acceleration and deceleration. Since the control gain is corrected, the control gain can be corrected to reflect the difference in characteristics between acceleration and deceleration.

It is a side view of a hydraulic excavator. It is a control block diagram which shows the control structure of an electric turning system. It is explanatory drawing which shows the correction calculation pattern of the control gain used for motor torque control. It is a flowchart figure which shows the process sequence of electric motor torque control. It is a flowchart figure which shows the process sequence of control gain correction | amendment calculation (pattern A). It is a flowchart figure which shows the process sequence of a control gain correction | amendment calculation (pattern B). It is a flowchart figure which shows the process sequence of control gain correction | amendment calculation (pattern C). It is a control block diagram concerning a second embodiment. It is a control block diagram concerning a third embodiment. It is explanatory drawing which shows the correction calculation pattern of the control gain which concerns on 3rd embodiment. It is a control block diagram concerning a conventional example. (A) is explanatory drawing which shows the example of speed command calculation, (B) is explanatory drawing which shows the example of torque command calculation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a hydraulic excavator that is an example of a work machine. The hydraulic excavator 1 includes a crawler-type lower traveling body 2, an upper revolving body 3 that is rotatably supported by the lower traveling body 2, and the upper revolving body. The working unit 4 is mounted on the body 3, and the working unit 4 is configured by using a boom 5, an arm 6, a bucket 7, and the like.

  FIG. 2 is a control block diagram showing a control configuration of an electric swing system applied to the hydraulic excavator 1. In the hydraulic excavator 1, the upper swing body 3 is connected via a gear type reduction gear (gear mechanism) 8. The upper swing body 3 is connected to the electric motor 9 and is operated to rotate based on torque control of the electric motor 9. In addition, as the electric motor 9, you may use the motor generator which functions as an electric motor and a generator.

  The hydraulic excavator 1 is provided with an electric motor torque control device 10 that performs torque control of the electric motor 9. The motor torque control device 10 according to the present embodiment includes an operation position detection unit 12 that detects an operation position of an operation lever (operation tool) 11, a motor speed detection unit 13 a that detects a speed ωa of the motor 9, and a speed of the upper swing body 3. A detection signal is input from the revolving body speed detection means 13b or the like that detects ωb, and the drive torque of the motor 9 is controlled according to these input signals. If the control target is a motor generator, only the drive torque is controlled. In addition, the regenerative torque can be controlled.

  The motor torque control device 10 includes a speed command calculating unit 14 that calculates a speed command ωd based on the operation position of the operation lever 11, and a speed feedback signal reading unit that reads the speed feedback signal ω of the motor 9 and / or the upper swing body 3. 15, a speed deviation calculating means 16 for calculating a speed deviation Δω between the speed command ωd and the speed feedback signal ω, and a torque command calculating means 17 for calculating a torque command Trd of the electric motor 9 based on the speed deviation Δω. Yes.

  For calculation of the torque command Trd, a control gain G1 that determines the ratio of the torque command Trd to the speed deviation Δω is used. For example, in the case of P control (proportional control), a control gain G1 that is a proportional element is used as a transfer function, and in the case of PI control (proportional integral control), a control gain G1 that is a proportional element and an integral element (T1) / S) is used as the transfer function. T1 is a time constant parameter, and s is a Laplace operator.

  The optimum value of the control gain G1 is a value that can achieve both control stability and responsiveness. In general, the maximum value is used within the range of the control gain that can ensure control stability. However, in the hydraulic excavator 1 that turns the upper swing body 3 via the gear type speed reducer 8, the backlash existing in the speed reducer 8 becomes an unstable element of control, and therefore, the control gain G1 is sacrificed at the sacrifice of responsiveness. It was necessary to make it smaller.

  For example, when the device gain of the reducer 8 (the ratio of the output speed to the command speed) is G2, the device gain G2 is large when the gear is not engaged due to backlash, and the device gain is obtained when the gear is engaged. G2 becomes smaller. Such fluctuation of the device gain G2 increases the minute command response of the electric motor 9 and may cause an unstable event such as hunting. Therefore, conventionally, in order to ensure the stability of the control, the control gain G1 The value of was reduced. As a result, even in a load situation where a large torque is required (load = 1 / M1s + c), a sufficient torque cannot be generated, resulting in a problem that the responsiveness is lowered. M1 is a sum of a pure load and the inertial force of the device, and c is a resistance coefficient of the device.

The above problems can be solved by making the control gain G1 variable according to the operating state. For example, when the gain of the entire system is G0 and T1≈0, the system gain G0 can be expressed by the following equation.
G0 = G1 × G2 / (M1s + c)
Here, when G0 is the optimum system gain, the optimum control gain G1 can be expressed by the following equation.
G1 = G0 / G2 × (M1s + c)
Since the device gain G2 and the load M1 are variables that change according to the driving situation, the control gain G1 can be adjusted (corrected) to an optimum value by grasping the device gain G2 and the load M1. Become. Specifically, the control gain G1 is corrected to the decreasing side in an operating situation where the load is small and backlash is affected, and the control gain G1 is corrected to the increasing side in an operating condition where the load is large. An optimum control gain G1 that can achieve both stability and responsiveness is obtained.
Hereinafter, the correction process of the control gain G1 will be described in detail.

  As shown in FIG. 2, the motor torque control device 10 includes control gain correction means 18 that corrects the control gain G1. The control gain correction means 18 includes a speed threshold ωd0 that defines an upper limit of the speed range in which the backlash of the speed reducer 8 affects, and when the speed command ωd is equal to or less than the speed threshold ωd0, the control gain G1 is corrected to the decreasing side. It has become. In this way, in the speed range where the backlash of the speed reducer 8 is affected, the control gain G1 can be reduced to improve the control stability, while in the speed range where the backlash of the speed reducer 8 is not affected. Can prevent a decrease in responsiveness by using an appropriate control gain G1. In particular, in the present embodiment, the control gain G1 is corrected in accordance with the speed command ωd. Therefore, in a situation where the operator expects a high response (the speed command ωd is large), the operator is urged to correct the control gain G1 to the decreasing side. It is possible to reliably prevent a control action against the intention.

  The control gain correction means 18 corrects the control gain G1 to the increase side when the speed command ωd exceeds the speed threshold value ωd0. In this way, it is possible to apply as large a control gain as possible in a speed range where the backlash of the speed reducer 8 does not affect, and to exhibit good responsiveness even under a heavy load condition. In particular, in the present embodiment, the control gain G1 is corrected according to the speed command ωd, so that the control gain G1 can be reliably increased in a situation where the operator expects a high response.

  Further, as shown in FIG. 3, the control gain correction means 18 has a correction calculation pattern (patterns A to C) for changing the correction value h multiplied by the control gain G1 in accordance with the speed command ωd. Among these correction calculation patterns, patterns B and C define a maximum value hmax and a minimum value hmin of the correction value h in the correction calculation pattern, and have a second speed threshold value ωd1 larger than the speed threshold value ωd0. When ωd is equal to or less than the speed threshold value ωd0, the control gain G1 is corrected to the decreasing side using the minimum value hmin, and when the speed command ωd exceeds the second speed threshold value ωd1, control is performed using the maximum value hmax. The gain G1 is corrected to increase, and when the speed command ωd exceeds the speed threshold value ωd0 and is equal to or less than the second speed threshold value ωd1, the control gain G1 is decreased using a correction value that will be described later in proportion to the speed command ωd. It is set to correct to the side or the increase side. In this way, it is possible to prevent the control gain G1 from changing suddenly between the speed range in which the control gain G1 is corrected to the decreasing side and the speed range in which the control gain G1 is corrected to the increasing side. It is possible to avoid the occurrence of speed fluctuations and impacts accompanying a sudden change in G1.

  The control gain correction means 18 determines whether the vehicle is accelerating or decelerating based on the comparison between the speed command ωd and the speed feedback signal ω, and uses different correction calculation patterns during acceleration and deceleration. The control gain G1 can be corrected. In this way, it is possible to correct the control gain G1 reflecting the difference in characteristics between acceleration and deceleration.

  Next, a specific control procedure of the motor torque control in the motor torque control device 10 will be described with reference to FIGS. However, the control gain G1, the time constant parameter T1, the stop time constant parameter T1stop, the stop correction value hstop, the speed threshold values ωd0, ωd1, and the like are given in advance.

  As shown in FIG. 4, in the motor torque control, the speed command ωd is calculated based on the operation position of the operation lever 11 (S1), and the speed feedback signal ω of the motor 9 and / or the upper swing body 3 is read (S2). ), A speed deviation Δω between the speed command ωd and the speed feedback signal ω is calculated (S3).

  Next, it is determined whether the vehicle is accelerating or decelerating based on a comparison between the speed command ωd and the speed feedback signal ω (S4). When it is determined that the vehicle is accelerating, the correction value h is calculated using the acceleration correction value calculation pattern (see FIG. 3) (S5: see FIGS. 5 to 7), and it is determined that the vehicle is decelerating. In this case, the correction value h is calculated using a correction value calculation pattern (not shown) for deceleration different from that for acceleration (S6).

  Next, it is determined whether or not the upper swing body 3 is in a turning stop state (S7). For example, when the state of the speed command ωd = 0 and the speed feedback signal ω = 0 continues for a predetermined time, it is determined that the turning is stopped. If it is determined that the vehicle is in the turning stop state, the stop correction value hstop is set as the correction value h to output the torque command Trd necessary for holding the stop position, and the stop time constant is set in the time constant parameter T1. The parameter T1stop is set (S8).

Next, the control gain G1 is multiplied by the correction value h to obtain the correction control gain G1 (S9), and the torque command Trd is calculated using the following formula (S10), and the torque output Tr based on the torque command Trd is calculated. (S11).
Torque command Trd = Δω × (G1 × h + T1 / s)

  FIG. 5 is a flowchart showing the processing procedure of the control gain correction calculation (pattern A). When calculating the correction value h using the pattern A, first, is the speed command ωd equal to or less than the speed threshold ωd0? It is determined whether or not (S21). If the determination result is YES, the minimum value hmin is set to the correction value h (S22), and if the determination result is NO, 1 is set to the correction value h (S23).

FIG. 6 is a flowchart showing the processing procedure of the control gain correction calculation (pattern B). When calculating the correction value h using the pattern B, first, is the speed command ωd equal to or less than the speed threshold ωd0? It is determined whether or not (S31). If the determination result is YES, the minimum value hmin is set as the correction value h (S32). On the other hand, if the determination result in step S31 is NO, it is determined whether or not the speed command ωd exceeds the second speed threshold value ωd1 (S33). If the determination result is YES, the maximum value hmax is set to the correction value h (S34). If the determination result is NO, a correction value proportional to the speed command ωd is calculated using the following equation. Then, the correction value h is set (S35).
Correction value h = hmin + {(hmax−hmin) / (ωd1−ωd0)} × (ωd−ωd0)

FIG. 7 is a flowchart showing the processing procedure of the control gain correction calculation (pattern C). When calculating the correction value h using the pattern C, first, is the speed command ωd equal to or less than the speed threshold ωd0? It is determined whether or not (S41). If the determination result is YES, the minimum value hmin is set as the correction value h (S42). On the other hand, when the determination result of step S41 is NO, it is determined whether or not the speed command ωd exceeds the second speed threshold value ωd1 (S43). If the determination result is YES, the maximum value hmax is set to the correction value h (S44). If the determination result is NO, a correction value proportional to the speed command ωd is calculated using the following equation. Then, the correction value h is set (S45).
Correction value h = 1 + {(hmax−hmin) / (ωd1−ωd0)} × (ωd−ωd0)

  According to the present embodiment configured as described above, the upper swing body 3 is connected to the electric motor 9 via the speed reducer 8, and the upper excavator 3 is turned based on the torque control of the electric motor 9. The motor torque control device 10 includes a speed command calculating means 14 for calculating a speed command ωd based on an operation position of an operation lever 11 for turning the upper swing body 3, and an electric motor 9. And / or speed feedback signal reading means 15 for reading the speed feedback signal ω of the upper-part turning body 3, speed deviation calculating means 16 for calculating the speed deviation Δω between the speed command ωd and the speed feedback signal ω, and the speed deviation Δω. Torque command calculating means 17 for calculating the torque command Trd of the motor 9 and a control gain G1 used for calculating the torque command Trd. Control gain correction means 18, the control gain correction means 18 includes a speed threshold ωd0 that defines an upper limit of the speed range in which the backlash of the speed reducer 8 affects, and when the speed command ωd is equal to or less than the speed threshold ωd0, Since the control gain G1 is corrected to the decreasing side, the control gain G1 can be reduced to improve control stability in the speed range where the backlash of the speed reducer 8 affects, while the backlash of the speed reducer 8 is improved. In a speed range where no influence is exerted, it is possible to prevent a decrease in responsiveness by using an appropriate control gain G1. In particular, in the present embodiment, the control gain G1 is corrected in accordance with the speed command ωd. Therefore, in a situation where the operator expects a high response (the speed command ωd is large), the operator is urged to correct the control gain G1 to the decreasing side. It is possible to reliably prevent a control action against the intention.

  Further, when the speed command ωd exceeds the speed threshold value ωd0, the control gain correction means 18 corrects the control gain G1 to the increase side. Therefore, in the speed range where the backlash of the speed reducer 8 does not affect as much as possible. By applying a large control gain, it is possible to show a good response even under a heavy load condition. In particular, in the present embodiment, the control gain G1 is corrected according to the speed command ωd, so that the control gain G1 can be reliably increased in a situation where the operator expects a high response.

  Further, the control gain correction means 18 has a correction calculation pattern (patterns B and C) for changing the correction value h multiplied by the control gain G1 in accordance with the speed command ωd, and the correction value h in the correction calculation pattern And a second speed threshold value ωd1 larger than the speed threshold value ωd0, and when the speed command ωd is equal to or less than the speed threshold value ωd0, the control gain G1 is decreased using the minimum value hmin. When the speed command ωd exceeds the second speed threshold value ωd1, the control gain G1 is corrected to the increasing side using the maximum value hmax, the speed command ωd exceeds the speed threshold value ωd0, and When the speed is less than the second speed threshold value ωd1, the control gain G1 is corrected to the decrease side or the increase side using a correction value proportional to the speed command ωd, so the control gain G1 is corrected to the decrease side. Between the speed range and the speed range where the control gain G1 is corrected to the increase side, the control gain G1 can be prevented from changing abruptly. Can be avoided.

  The control gain correction means 18 determines whether the vehicle is accelerating or decelerating based on the comparison between the speed command ωd and the speed feedback signal ω, and uses different correction calculation patterns during acceleration and deceleration. Since the control gain G1 is corrected, it is possible to correct the control gain G1 reflecting the difference in characteristics between acceleration and deceleration.

  Next, an electric motor torque control device 10B according to a second embodiment of the present invention will be described with reference to FIG. However, about the part which is common in the said embodiment, the description of the said embodiment is used by providing the same code | symbol as the said embodiment.

  FIG. 8 is a control block diagram according to the second embodiment, in which the motor torque control device 10B of the second embodiment calculates the torque command Trd after calculating the torque command Trd based on the control gain G1 before correction. The point which correct | amends Trd based on the correction value h is different from the said embodiment. Even with such an electric motor torque control device 10B, it is possible to achieve the same effects as in the above embodiment, but the time constant parameter T1 is also affected by the correction value h, and therefore caution is required in PI control. is there.

  Next, an electric motor torque control apparatus 10C according to a third embodiment of the present invention will be described with reference to FIGS. However, about the part which is common in the said embodiment, the description of the said embodiment is used by providing the same code | symbol as the said embodiment.

  FIG. 9 is a control block diagram according to the third embodiment, and FIG. 10 is an explanatory diagram showing a control gain correction calculation pattern according to the third embodiment. An electric motor torque control device 10C according to the third embodiment includes: The point which correct | amends the control gain G1 based on the speed feedback signal (omega) (omegaa) of the electric motor 9 is different from the said embodiment. In this way, when the control gain G1 is corrected based on the speed feedback signal ω, the speed fluctuation caused by the backlash of the speed reducer 8 is reduced as compared with the case where the speed feedback signal ω (ωb) of the upper swing body 3 is used. It can be clearly understood and reflected in the control.

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 3 Upper turning body 8 Reduction gear 9 Electric motor 10 Motor torque control apparatus 11 Operation lever 12 Operation position detection means 13a Motor speed detection means 13b Revolving body speed detection means 14 Speed command calculation means 15 Speed feedback signal reading means 16 Speed deviation Calculation means 17 Torque command calculation means 18 Control gain correction means

Claims (4)

An electric motor torque control device for a working machine, wherein an operating body is linked to an electric motor via a gear mechanism, and the operating body is operated based on torque control of the electric motor,
The electric motor torque control device
Speed command calculating means for calculating a speed command based on an operation position of an operating tool for operating the operating body;
Speed feedback signal reading means for reading a speed feedback signal of the electric motor and / or the operating body;
Speed deviation calculating means for calculating a speed deviation between the speed command and the speed feedback signal;
Torque command calculating means for calculating a torque command of the electric motor based on the speed deviation;
Control gain correction means for correcting the control gain used for the calculation of the torque command,
The control gain correction means includes a speed threshold value that determines an upper limit of a speed range in which the backlash of the gear mechanism affects, and when the speed command or the speed feedback signal of the motor is equal to or lower than the speed threshold value, the control gain correction means A motor torque control device for a work machine, wherein the motor torque control device corrects to a decrease side.   2. The electric motor for a work machine according to claim 1, wherein the control gain correction means corrects the control gain to an increase side when the speed command or a speed feedback signal of the electric motor exceeds the speed threshold. Torque control device.   The control gain correction means has a correction calculation pattern for changing a correction value multiplied by the control gain in accordance with the speed command or the speed feedback signal of the motor, and the maximum value of the correction value in the correction calculation pattern And a second speed threshold value that is larger than the speed threshold value, and when the speed command or the speed feedback signal of the motor is equal to or lower than the speed threshold value, the control gain is set using the minimum value. When the speed command or the speed feedback signal of the motor exceeds the second speed threshold value, the control gain is corrected to the increase side using the maximum value, and the speed command or When the speed feedback signal of the motor exceeds the speed threshold and is equal to or lower than the second speed threshold, the speed command or the electric power Working machine motor torque control apparatus according to claim 2, wherein the correcting the reduction side or the increase side the control gain by using the correction value proportional to the speed feedback signal of the machine.   The control gain correction means determines whether the vehicle is accelerating or decelerating based on a comparison between the speed command and the speed feedback signal, and uses the different correction calculation patterns for acceleration and deceleration. The motor torque control device for a work machine according to any one of claims 1 to 3, wherein the gain is corrected.

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