Drive control device, drive control method

Abstract

To secure a damping effect at the time of tire slip while preventing torque offset.SOLUTION: A drive control device that can be mounted on a vehicle having a drive part includes a torque command acquisition part for acquiring or generating a torque command value, a torque correction part for correcting the torque command value using correction torque so as to reduce resonance in the drive part on the basis of a rotation speed of a control object, and an idling information acquisition part for acquiring information on presence / absence of idling of a tire, wherein the torque correction part acquires information on tire idling occurrence by the idling information acquisition part, and then changes a parameter for determining the correction torque from the rotation speed so that the correction torque increases when a magnitude of the torque command value decreases.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, in vehicles in which power is transmitted from an on-board drive unit to the wheels and tires mounted on the wheels via a drive shaft, drive control technology is known that determines the slippage state of the wheels and tires mounted on the wheels and suppresses slippage while taking into account the effect of resonance due to the twisting of the drive shaft. Patent Document 1 discloses a vehicle vibration control device that includes at least a motor / generator as a power source for driving the wheels, a wheel slip control means for controlling the wheel power so that the slip ratio of the wheels becomes a predetermined slip ratio, and a vibration damping control means for suppressing rotational vibration of the wheel drive system from the motor / generator to the wheels by torque control of the motor / generator, characterized in that the vibration damping effect of the vibration damping control means is suppressed when the wheel slip control means is operating. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-273328 [Overview of the project] [Problems that the invention aims to solve]

[0004] The invention described in Patent Document 1 has room for improvement in its handling of tire slippage. [Means for solving the problem]

[0005] A drive control device according to a first aspect of the present invention is a drive control device that can be mounted on a vehicle having a drive unit, and comprises a torque command acquisition unit that acquires or generates a torque command value, a torque correction unit that corrects the torque command value using a correction torque so as to reduce resonance in the drive unit based on the rotational speed of the controlled object, and a slip information acquisition unit that acquires information on whether or not the tires are slipping, wherein the torque correction unit, after acquiring information on the occurrence of tire slippage by the slip information acquisition unit, changes a parameter that determines the correction torque from the rotational speed so as the magnitude of the torque command value decreases, the correction torque increases. A second aspect of the present invention is a drive control method performed by a drive control device that can be mounted on a vehicle having a drive unit, and includes a torque command acquisition step of acquiring or generating a torque command value, a torque correction step of correcting the torque command value using a correction torque so as to reduce resonance in the drive unit based on the rotational speed of the controlled object, and a slip information acquisition step of acquiring information on whether or not the tires are slipping, wherein in the torque correction step, after information on the occurrence of tire slippage is acquired by the slip information acquisition step, the parameter for determining the correction torque from the rotational speed is changed so as the magnitude of the torque command value decreases, the correction torque increases. [Effects of the Invention]

[0006] According to the present invention, it is possible to prevent torque offset while ensuring vibration damping during tire slip. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0007] [Figure 1] Overall configuration diagram of a vehicle equipped with a drive control system. [Figure 2] Diagram illustrating the vehicle's drive system. [Figure 3] Diagram showing the motor's behavior during adhesion and free-spinning. [Figure 4] Block diagram of the drive control device in the first embodiment [Figure 5] Block diagram of simulator tracking control [Figure 6] Figure showing an example of a method for correcting the reference rotational speed [Figure 7] Figure explaining the behavior of the reference rotational speed [Figure 8] Block diagram showing the vibration control method of the high-pass filter FB method [Figure 9] Figure showing an overview of a method for changing the FB gain [Figure 10] Figure showing an example of a method for determining the threshold value [Figure 11] Figure showing an example of a method for restoring the FB gain [Figure 12] Figure showing different methods for restoring the FB gain [Figure 13] Figure showing the result of simulating the torque change during wheel spin [Figure 14] Figure showing the result of simulating the torque change during wheel spin [Figure 15] Figure showing the result of simulating the torque change during wheel spin [Figure 16] Block diagram of the drive control device in the second embodiment [Figure 17] Figure showing the behavior of the torque correction unit when obtaining the brake operation amount as vehicle information [Figure 18] Configuration of vibration control in the torque correction unit when obtaining the tire rotational speed as vehicle information [Figure 19] Figure showing the behavior of the torque correction unit when obtaining the wheel spin information from the upper controller as vehicle information

Embodiments for Carrying Out the Invention

[0008] —First Embodiment— Hereinafter, referring to FIGS. 1 to 15, the first embodiment of the drive control device will be described.

[0009] Figure 1 is an overall configuration diagram of a vehicle 21 equipped with a drive control device 1. The vehicle 21 is equipped with tires 20, wheel speed sensors 31, and wheel cylinders 36. Hereinafter, the wheels and the tires 20 mounted on the wheels will be collectively referred to as "wheels." The tires 20, wheel speed sensors 31, and wheel cylinders 36 are provided at the front and rear, and left and right of the vehicle 21, respectively, and their positions are identified by combinations of F and R and L and R. Specifically, FL wheels refer to the left front wheel, FR wheels to the right front wheel, RL wheels to the left rear wheel, and RR wheels to the right rear wheel, and each of the FL, FR, RL, and RR wheels is fitted with a tire 20FL, 20FR, 20RL, and 20RR that makes contact (adhere) with the road surface. The wheel speed sensors 31 and wheel cylinders 36 are similarly labeled with FL, FR, etc.

[0010] Vehicle 21 is equipped with a motor 22, which serves as a drive device that generates driving torque, i.e., driving force, to control the acceleration and deceleration of vehicle 21 in the direction of travel. The drive control device 1 receives power from a battery (not shown) mounted on vehicle 21 and controls the current of motor 22 to generate driving torque according to the torque command value described later. The driving torque generated by motor 22 is transmitted to the left and right drive shafts 24L and 24R via the differential gear 23, and then to the left and right front tires 20FL and 20FR which are directly connected to each drive shaft 24L and 24R, thereby allowing the drive control device 1 to accelerate and decelerate vehicle 21. Although this description assumes an electric vehicle equipped with motor 22, an engine may be used as the drive device (drive source) instead of motor 22. Also, although this description assumes front-wheel drive, vehicle 21 may be rear-wheel drive or four-wheel drive.

[0011] The vehicle 21 is equipped with a steering control mechanism 30 for controlling the direction of travel, a brake control mechanism 33, and a driving control device 25 (sometimes called a higher-level controller) that calculates command values ​​for the drive control device 1. The vehicle 21 is also equipped with a steering control device 28 that controls the steering control mechanism 30 based on command values ​​from the driving control device 25, and a braking control device 35 that controls the brake control mechanism 33 based on the command values ​​and adjusts the brake force distribution to each wheel.

[0012] Although not shown in detail in Figure 1, the drive control device 1 includes a power semiconductor (e.g., an IGBT) that controls the current of the motor 22 by switching, a CPU, ROM, RAM, and input / output devices for controlling the switching of the power semiconductor. The ROM stores a program that implements the drive control described later. As will be described in detail later, the drive control device 1 performs the following calculation using the torque command value 2 received from the travel control device 25 and the motor rotation angle 60 and motor rotation speed 61 obtained by the rotation angle sensor 51 attached to the motor 22. That is, the drive control device 1 calculates the motor torque to be generated and controls the current flowing to the motor 22 by switching the power semiconductor to obtain this motor torque.

[0013] Next, the operation of the brakes of vehicle 21 will be explained. When the driver is operating vehicle 21, the force applied by the driver to the brake pedal 32 is amplified by a brake booster (not shown) if necessary, and a master cylinder (not shown) generates hydraulic pressure corresponding to that force. The generated hydraulic pressure is supplied via the brake control mechanism 33 to wheel cylinders 36FL, 36FR, 36RL, and 36RR provided on each wheel. The wheel cylinders 36FL to 36RR consist of a cylinder, piston, pad, disc rotor, etc. (not shown), and the piston is propelled by the working fluid supplied from the master cylinder, and the pad connected to the piston is pressed against the disc rotor.

[0014] Since the disc rotor rotates with the wheel, the brake torque acting on the disc rotor becomes the braking force acting between the wheel and the road surface. As a result, braking force can be generated on each wheel in response to the driver's brake pedal operation. It is not mandatory for the vehicle 21 to be equipped with a brake booster or master cylinder. For example, the brake pedal 32 and the brake control mechanism 33 could be directly connected, so that the brake control mechanism 33 operates directly when the driver presses the brake pedal 32.

[0015] The braking control device 35, although not shown in detail in Figure 1, includes, for example, a CPU, ROM, RAM, and input / output devices. The braking control device 35 receives inputs such as a combine sensor 34 capable of detecting longitudinal acceleration, lateral acceleration, and yaw rate, wheel speed sensors 31FL, 31FR, 31RL, and 31RR installed on each wheel, sensor signals from a steering angle detection device 41 via a steering control device 28 (described later), and brake force command values ​​from the aforementioned driving control device 25. The output of the braking control device 35 is connected to a brake control mechanism 33, which has a pump and control valves (not shown), and can generate any braking force on each wheel independently of the driver's brake pedal operation.

[0016] The driving control device 25 communicates a brake force command value to the braking control device 35, thereby generating an arbitrary braking force in the vehicle 21. In autonomous driving where no driver input is required, the driving control device 25 plays a role in automatically applying the brakes. However, the braking control device 35 is not an essential component of the vehicle 21, and other actuators such as brake-by-wire may be used instead.

[0017] Next, the steering operation of the vehicle 21 will be described. The steering torque and steering angle input by the driver via the steering wheel 26 are detected by the steering torque detection device 27 and the steering angle detection device 41, respectively. Based on the detected steering torque and steering angle, the steering control device 28 controls the steering motor 29 to generate assist torque. Although not shown in detail in Figure 1, the steering control device 28, like the braking control device 35, includes, for example, a CPU, ROM, RAM, and input / output devices.

[0018] The steering control mechanism 30 moves due to the combined force of the driver's steering torque and the assist torque from the steering motor 29, thereby operating the front wheels (FL wheels, FR wheels). Meanwhile, the reaction force from the road surface is transmitted to the steering control mechanism 30 in response to the operation of the front wheels, and this is transmitted to the driver as road reaction force. Note that the steering torque detection device 27 is not an essential component of the vehicle 21, and the steering control device 28 may not operate when the driver operates the steering wheel 26, and no assist torque may be generated (a so-called manual steering mechanism).

[0019] The steering control device 28 can generate torque using the steering motor 29 and control the steering control mechanism 30 independently of the driver's steering input. Therefore, the driving control device 25 can control the front wheels to any desired steering angle by communicating steering force command values ​​to the steering control device 28, and plays a role in automatically steering in autonomous driving where there is no driver input. However, the steering control device 28 is not an essential component of the vehicle 21, and the vehicle 21 may be equipped with other actuators such as steer-by-wire.

[0020] Next, the operation of the accelerator of the vehicle 21 will be described. The amount the driver depresses the accelerator pedal 37 is detected by the stroke sensor 38, converted into a torque command value 2 by the driving control device 25, and input to the drive control device 1. The driving control device 25 and the drive control device 1, although not shown in detail in Figure 1, also have components such as a CPU, ROM, RAM, and input / output devices, similar to the braking control device 35. The driving control device 25 controls the motor torque of the motor 22 according to the amount the accelerator pedal 37 is depressed, for example. As a result, the vehicle 21 can be accelerated in response to the driver's accelerator pedal operation.

[0021] Furthermore, the driving control device 25 can command the motor torque of the motor 22 independently of the driver's accelerator operation. Therefore, by communicating the torque command value 2 to the drive control device 1, the driving control device 25 can control the motor torque of the motor 22 to generate any desired acceleration in the vehicle 21, and in autonomous driving where there is no driver input, it plays the role of automatically accelerating.

[0022] Furthermore, on slippery surfaces, the system modifies the torque command value 2 to prevent tire slippage (hereinafter also referred to as "slip"), regardless of the driver's accelerator or brake commands, thereby performing slip control (traction control). Note that the vehicle 21 does not necessarily have to be an electric vehicle with an electric motor as its main drive system; it may also have an engine as its main drive system. In this case, the driving control device 25 calculates the throttle opening degree according to the amount the accelerator pedal 37 is pressed, and the drive control device 1 controls the engine operating state to achieve the throttle opening degree.

[0023] As described above, in this embodiment, the driving control device 25 calculates command values ​​(brake force command value, steering force command value, torque command value 2 (acceleration command value)) based on signals obtained from various sensors and the like installed on the vehicle 21, and transmits the calculated command values ​​(brake force command value, steering force command value, torque command value 2) to each control device (braking control device 35, steering control device 28, drive control device 1), thereby controlling the braking force, front wheel steering angle, acceleration, etc. of the vehicle 21, and allowing arbitrary control of the driving state of the vehicle 21.

[0024] In the above description, the vehicle 21 is equipped with a steering wheel 26, an accelerator pedal 37, and a brake pedal 32, but it does not have to be equipped with these input devices. In this case, it would be a fully autonomous vehicle that does not require driver operation, or a remotely driven vehicle that operates by receiving driving commands remotely, and the driving control device 25 would act as its brain. Alternatively, the driving control device 25 may not exist, and the drive control device 1 may calculate (generate) these command values.

[0025] In the following explanation, for the sake of simplicity, the drive shaft connected to the drive wheel, which is connected to the motor 22 and rotated, will be referred to as the drive shaft 24, the tire mounted on the drive wheel will be referred to as the tire 20, and the sensor installed on the drive wheel to measure the wheel speed will be referred to as the wheel speed sensor 31.

[0026] The drive unit of the vehicle 21 will be described with reference to Figures 2 and 3. The drive unit includes a motor 22, a differential gear 23, and a drive shaft 24. Figure 2(a) shows the component configuration of the drive unit, and Figure 2(b) shows the physical model of the drive unit. The drive torque generated in the motor 22 is transmitted to the differential gear 23 via the reduction gear 52, and is distributed to the left and right wheels by the differential gear 23. The drive torque distributed to the left and right wheels is transmitted to the tires 20 via the drive shaft 24.

[0027] As shown in Figure 2(b), the drive unit is represented by a two-inertia system physical model in which a spring-like drive shaft 24 connects the inertial motor 22 and the tire 20. Although not shown in this figure, the tire 20 is in contact with the road surface, and a nonlinear frictional force is generated between the tire 20 and the road surface. Furthermore, the motor 22 is mounted on the vehicle body via a motor mount 53. Since the motor mount 53 generally has an elastic material for shock absorption, a spring element is also assumed between the motor 22 and the vehicle body, as shown in Figure 2(b).

[0028] Figure 3 shows the behavior of motor 22 during adhesion and free-running. When the torque of motor 22 fluctuates rapidly, vibrations occur in the motor rotation speed 61, as shown in Figure 3. Figure 3(a) shows the behavior of motor 22 during adhesion, and Figure 3(b) shows the behavior of motor 22 during free-running. In both Figures 3, the horizontal axis represents time, and the vertical axis represents the motor rotation speed 61. In Figures 3(a) and (b), a step-like torque is generated in motor 22 from 0.5 seconds. As a result, the motor rotation speed 61 is vibrating from 0.5 seconds.

[0029] The vibration at motor rotation speed 61 is a resonance phenomenon caused by the drive shaft 24 acting as a spring. However, it may also be a resonance phenomenon caused by the spring element of the motor mount 53. It is known that the vibration frequency at motor rotation speed 61 in this case varies depending on whether the tire 20 is in contact with the road surface or is spinning freely. This frequency differs depending on the shape of the tire 20 and drive shaft 24 configured in the vehicle 21, i.e., depending on the vehicle type. In the example shown in Figure 3, when the tire is in contact with the road surface, a vibration of about 4 Hz occurs as shown in Figure 3(a), and when the tire is spinning freely, a vibration of about 10 Hz occurs as shown in Figure 3(b).

[0030] Figure 4 is a block diagram of the drive control device 1. The drive control device 1 includes a torque command acquisition unit 3, a rotational speed calculation unit 4, a slip information acquisition unit 5, and a torque correction unit 6.

[0031] The torque command acquisition unit 3 receives a torque command value 2 from the driving control device 25, which is a higher-level controller. The torque command value 2 is a command value for generating motor torque in the motor 22 in order to generate a predetermined acceleration in the vehicle 21.

[0032] The torque command value 2 is received as a positive value to accelerate the vehicle 21 when, for example, the driver is pressing the accelerator pedal 37. Conversely, when the driver is not pressing the accelerator pedal 37 or is pressing the brake pedal 32, the torque command value 2 is received as a negative value corresponding to regenerative braking or engine braking. The torque command acquisition unit 3 receives the torque command value 2 from the driving control device 25 using digital communication such as CAN (Controller Area Network). As mentioned above, it is also possible that the driving control device 25 does not exist, and the drive control device 1 calculates (generates) the command value.

[0033] The rotational speed calculation unit 4 calculates the motor rotational speed 61 by differentiating the motor rotation angle 60 obtained by the rotational angle sensor 51 attached to the motor 22 with respect to time (calculating the amount of change per unit time). Generally, sensors capable of obtaining the absolute angle of the motor 22, such as encoders and resolvers, are used as the rotational angle sensor 51. The slip information acquisition unit 5 estimates whether the tire 20 is slipping relative to the road surface from the motor rotational speed 61 calculated by the rotational speed calculation unit 4. However, as will be described later, the slip information acquisition unit 5 may also acquire slip detection information and traction control operation information from a higher-level controller (for example, a driving control device 25).

[0034] The slip information acquisition unit 5 can estimate whether the tire 20 is slipping by extracting specific frequency components from the motor rotation speed 61, for example. For example, as shown in Figure 3, for a controlled object where the resonant frequency is about 4 Hz when the tire is in contact with the surface and about 10 Hz when the tire is slipping, the unit extracts either the 10 Hz frequency component or both the 4 Hz and 10 Hz frequency components. Based on the extracted frequency components of the motor rotation speed 61, the slip information acquisition unit 5 determines whether the tire 20 is in a contact state or a slipping state, and outputs the slip determination result as slip information 8. This determination can be made, for example, based on the presence or absence of a predetermined frequency component at the motor rotation speed 61, or by comparing the magnitudes of the first frequency component and the second frequency component at the motor rotation speed 61.

[0035] When the slip information acquisition unit 5 calculates the difference in resonant frequency components between tire adhesion and tire slippage using a bandpass filter or Fourier transform, it determines that the tire is slipping if the resonant frequency component during tire slippage is greater than the resonant frequency component during tire adhesion. Alternatively, when calculating the amplitude using a Fourier transform with frequency f as the resonant frequency during tire slippage, the slip information acquisition unit 5 determines that the tire 20 is in a slipping state if the amplitude exceeds a predetermined value. The slip information 8 obtained by the slip information acquisition unit 5 may be represented, for example, as a binary number with adhesion being 0 and slippage being 1, or as a continuous value from 0 (perfect adhesion) to 1 (slippage) depending on the estimated slip ratio of the tire.

[0036] The torque correction unit 6 corrects the torque to reduce resonance in the drive unit and calculates the final torque value 7 based on the torque command value 2 obtained from the torque command acquisition unit 3, the motor rotation angle 60, the motor rotation speed 61 obtained from the rotation speed calculation unit 4, and the slip information 8 obtained from the slip information acquisition unit 5. Details of this calculation will be described later. Then, the power semiconductor is switched to control the current flowing to the motor 22 so that the motor 22 generates the final torque value 7. In this case, if the motor 22 is a permanent magnet synchronous motor, it is common to perform vector control based on the motor rotation angle 60. The motor rotation angle 60 of the motor 22 is obtained by a rotation angle sensor 51 attached to the motor 22 and input to the rotation speed calculation unit 4 of the drive control device 1.

[0037] Referring to Figures 5 to 7, a torque correction method for reducing resonance in the torque correction unit 6 will be explained.

[0038] Figure 5 is a block diagram of Simulator Following Control (SFC), which is widely used in the drive control device of the vehicle 21. In this control method, first, a band-rejection filter (notch filter) 73 is applied to the torque command value 2 to remove frequency components corresponding to the resonant frequency from the torque command value 2. Next, a correction torque 76, described later, from one sample prior is added to generate the final torque value 7. The final torque value 7 is the torque that the motor 22, which is the target of control, will ultimately generate, and at the same time, the final torque value 7 is input to the simulator 70 within the torque correction unit 6. Based on the input final torque value 7, the simulator 70 generates a reference rotational speed 71 using a physical model of the target of control.

[0039] The role of this reference rotational speed 71 is to represent an ideal rotational speed without vibration. For example, the reference rotational speed 71 without vibration components is obtained by integrating the final torque value 7 and dividing it by the vehicle weight converted to the motor shaft. Then, the difference between the reference rotational speed 71 and the motor rotational speed 61 is calculated using the reference rotational speed 71 as the command value, and this is used as the corrected torque 76 for vibration damping control via the FB (feedback) gain 72. The FB gain 72 represents the multiplication of the proportionality constant, but it may also be combined with a filter having phase lead or phase lag characteristics. In general, the stability of the feedback control tends to improve by including a phase lead compensator.

[0040] This reference rotational speed 71 may exhibit a steady-state deviation from the motor rotational speed 61 due to modeling errors in the physical model of the controlled object and the influence of disturbances. As described later, this steady-state deviation results in an offset of the final torque value 7 to the torque command value 2, which is undesirable. Therefore, the simulator 70 corrects the reference rotational speed 71 by acquiring not only the final torque value 7 but also the motor rotational speed 61 and slip information 8.

[0041] Figure 6 shows an example of a correction method for the reference rotational speed 71. Here, we will explain a correction method using a same-dimensional observer. The same-dimensional observer in Figure 6 assumes that the rotational motion equations of the controlled object can be expressed in the form of the state equation in Equation 1 and the output equation in Equation 2.

[0042] dx / dt = A x + B u ···(Equation 1)

[0043] y = C x ···(Equation 2)

[0044] Here, x represents the state vector, and dx / dt represents the time derivative of the state vector. Also, A, B, and C are matrices determined by the physical model of the controlled object, u is the input to the controlled object, and y is the observable output of the controlled object. Furthermore, in Figure 6, K is the gain matrix, and it works to reduce the error between the estimated output and the actual output by multiplying the difference between the output estimated by the observer and the observed actual output by the K matrix and feeding it back. In Figure 6, the input u is the final torque value of 7, the output y is the motor rotation speed of 61 in the actual controlled object, and the output of the observer is the estimated value of the motor rotation speed of 61. For example, the ideal rotational motion equation that does not include torsional vibration of the drive unit can be expressed as shown in the state equation in Equation 3 and the output equation in Equation 4.

[0045]

number

[0046]

number

[0047] Here, J m The inertia of motor 22 is J L This represents the inertia on the load side. Note that in this modeling, regardless of whether the tire is sticky or slipping, J L Let be the sum of the tires and the body. Also, ω m is the motor rotation speed of 61, N is the reduction ratio between the motor rotation axis and the axle rotation axis, T is the motor rotation speed of 61, T is the reduction ratio between the motor rotation axis and the axle rotation axis.d is the disturbance torque, T m represents the final torque value 7. The reduction ratio is the product of the reduction ratio of the motor's own reduction gear and the differential gear. Since the state vector of this equation of motion is two-dimensional, it will be referred to as the "two-dimensional observer" hereafter.

[0048] On the other hand, as a higher-dimensional modeling, when formulating the equation of rotational motion that separates the inertia of the motor 22 and the tire 20 and includes the torsion between the two, it can be expressed as shown in the state equation of Equation 5 and the output equation of Equation 6.

[0049]

Equation

[0050]

Equation

[0051] Here, J m is the inertia of the motor 22, J L represents the inertia on the load side. However, the inertia on the load side is the sum of the tire and the vehicle body when the tire is adhered, and is the value of only the tire when the tire is spinning. Also, ω m is the motor rotation speed 61, θ s is the torsion angle (the difference between the motor rotation angle 60 and the tire rotation angle), ω w is the tire rotation speed 63, K s is the torsion stiffness of the drive shaft 24, K sd is the torsion viscosity of the drive shaft 24, N is the reduction ratio between the motor rotation axis and the axle rotation axis, T d is the disturbance torque, T m represents the final torque value 7. Since the state vector of this equation of motion is four-dimensional, it will be referred to as the "four-dimensional observer" hereafter.

[0052] As shown in Equation 5, the four-dimensional observer has the inertia J on the load side in the A matrix LThe model includes different values ​​for when the tire is gripping and when it is spinning, so the variable values ​​need to be changed between the two. Also, the K matrix is ​​generally set so that the eigenvalues ​​(observer poles) of matrix A-KC are predetermined values, and if matrix A changes, matrix K must also be changed. Therefore, as shown in Figure 6, the values ​​of matrix A and matrix K are changed based on the spinning information 8. These observer poles have the characteristic that the higher the value set, the closer the observer's estimated value becomes to the actual value. Furthermore, as shown in Figure 6, in addition to the C matrix shown in equation 6, the estimated tire rotation speed 63e, which is an estimated value of the tire rotation speed 63, is obtained by using the C matrix shown in equation 7.

[0053]

number

[0054] Referring to Figure 7, the behavior of the reference rotational speed 71 in the 2D observer and the 4D observer will be explained. Figure 7 shows the simulation results. Figure 7(a) shows the time waveform when the estimated motor rotational speed 61e, which is an estimated value by the 2D observer, is used as the reference rotational speed 71. Figure 7(b) shows the estimated motor rotational speed 61e and estimated tire rotational speed 63e, which are estimated values ​​by the 4D observer. In both Figure 7(a) and Figure 7(b), tire slip occurs at 0.2 seconds, and then, 0.1 seconds later at 0.3 seconds, the higher-level controller (driving control device 25) detects the slippage and reduces the torque command value 2. At this time, a torsional resonance of 12 Hz occurs in the vehicle model assumed in the simulation.

[0055] The simulation results using the two-dimensional observer shown in Figure 7(a) are explained below. When the reference rotational speed 71 for simulator tracking control is set to the motor rotational speed 61, the observer poles are made small to avoid the influence of vibration components. In Figure 7(a), the observer poles are set to 2Hz, which is sufficiently small compared to the torsional resonance frequency. Therefore, torsional vibrations are almost invisible at the reference rotational speed 71. However, there is a delay of about 0.1 seconds compared to the actual motor rotational speed 61, and this delay may affect the vibration damping performance, so the observer poles should be designed to maximize the vibration damping effect. Using a two-dimensional observer has the advantage of providing a clear view of the control design and being easy to implement.

[0056] The simulation results using the 4D observer shown in Figure 7(b) are explained below. As will be explained in detail later, when the reference rotation speed 71 for simulator tracking control is set to the tire rotation speed 63, the vibration damping effect is enhanced by setting the observer poles to sufficiently high accuracy and low error to estimate the tire rotation speed 63. Here, the observer poles are set to 20Hz, a value large compared to the torsional resonance frequency, and in the upper part of Figure 7(b), there is no discrepancy at all between the motor rotation speed 61 and the estimated motor rotation speed 61e. In the lower part of Figure 7(b), there is also little discrepancy between the tire rotation speed 63 and the estimated tire rotation speed 63e after 0.3 seconds.

[0057] The discrepancy between 0.2 and 0.3 seconds in the lower part of Figure 7(b) is due to a modeling error, as the tire slippage information 8 remains in a sticky state only during this 0.1 second period, even though the tire is actually slipping. However, as will be described later, the FB gain 72 of the vibration damping control is reduced during this time period, so the impact on vibration damping control is small. Using a 4D observer allows the observer pole to be raised, thus obtaining the tire rotation speed 63 including vibration. Therefore, by adopting the tire rotation speed 63 as the reference rotation speed 71 for simulator tracking control in "speed difference feedback control," a high vibration damping effect can be obtained. However, the "tire rotation speed 63" referred to here is the value obtained by multiplying the rotation speed difference caused by the gear ratio of the motor 22 and the tire 20 and converting it to the motor shaft.

[0058] The above explains the simulator tracking control as an example of vibration damping control, and describes how to modify the reference rotational speed 71 using an observer. However, the vibration damping control that can be applied within the torque correction unit 6 is not limited to simulator tracking control. For example, Figure 8 shows a vibration damping control method using a high-pass filter FB method. A two-stage high-pass filter is applied to the motor rotational speed 61, the vibration component is extracted, multiplied by the FB gain 72, and subtracted from the torque command value 2 to obtain a final torque value of 7. The high-pass filter FB method is a simple and easy-to-implement method in that it does not require the implementation of the observer mentioned above.

[0059] Referring to Figures 9 to 12, the method by which the torque correction unit 6 changes the FB gain 72 will be explained. It has been known that vibration damping control can sometimes worsen the responsiveness of wheel slip control such as traction control. Therefore, in this embodiment, the FB gain 72 is not increased while the traction control is experiencing a torque change due to slip detection, i.e., a torque decrease, and is increased after the torque has changed sufficiently to enhance the vibration damping effect.

[0060] Figure 9 shows an overview of the method for changing the FB gain 72. The upper part of Figure 9 shows the time change of the torque command value 2 from the higher level, and the lower part of Figure 9 shows the time change of the FB gain 72. The vertical time in the upper and lower parts of Figure 9 coincides. The timing indicated by the first dashed line is called time t11, and the timing indicated by the second dashed line is called time t12.

[0061] In Figure 9, at time t11, some time after time t0 on the left, the higher-level controller detects slippage, and subsequently reduces the torque command value 2. The torque correction unit 6 does not change the FB gain 72 at time t11, but increases the FB gain 72 from time t12, when the torque command value 2 has changed sufficiently. In this way, the torque correction unit 6 increases the FB gain 72 after a predetermined time has elapsed since detecting slippage, or after predetermined conditions have been met.

[0062] Three conditions, for example, can be considered for increasing the FB gain of 72. You may adopt only one of the three conditions described below, or you may adopt multiple conditions. If you adopt multiple conditions, you may use an AND condition, an OR condition, or a combination of both. Specifically, you may increase the FB gain of 72 if the first or second condition is met AND the third condition is also met.

[0063] The first condition is that the change in torque command value 2 after slippage detection exceeds a threshold, as indicated by symbol 81. For example, if the threshold is set to 100 Nm, then if the torque command value 2 at time t11 is 150 Nm and slippage is detected, causing a torque reduction, the point at which the torque command value decreases to 50 Nm (150-100) is t12.

[0064] The second condition is that the torque command value 2 after slippage detection reaches a predetermined threshold, as indicated by reference numeral 82. For example, if the threshold is set to 30 Nm, time t12 will be the point at which the torque command value 2 decreases after time t11 when slippage is detected. In this case, the magnitude of the torque command value 2 at time t11 is not considered. Note that the threshold may be a value based on the torque command value 2 at time t11, rather than the torque command value 2 itself. For example, if the threshold is set to 1 / 2 (50%), then if the torque command value 2 at time t11 is 150 Nm, time t12 will be the point at which the torque decreases to half of that, 75 Nm.

[0065] The third condition is that a predetermined threshold of time elapses from the detection of slippage, as indicated by reference numeral 83. For example, if the threshold is set to 0.2 seconds, then regardless of the change in the torque command value 2 since the detection of slippage, time t12 will be the point in time t11 that has elapsed 0.2 seconds.

[0066] The three conditions described above each have different effective use cases and can be used in combination. Note that Figure 9 shows an example where the FB gain 72 is not increased until the conditions are met; however, the FB gain 72 may be increased simultaneously with the detection of idle speed, and the rate of increase of the FB gain 72 may be increased once the conditions are met.

[0067] Referring to Figure 10, an example of the threshold determination method described above is shown. Here, we will explain the setting of the predetermined value 82, that is, the threshold after the change in the torque command value 2 after slip detection. Figure 10 shows the time progression of the motor rotation speed 61, the estimated tire force value 64, the torque command value 2, and the FB gain 72 from top to bottom. However, in Figure 10, the estimated tire force value 64 converted to the torque of the motor shaft is shown. The four figures shown in Figure 10 have the same time in the vertical direction. The first dashed line shows time t21, and the second dashed line shows time t22. The example of the time progression shown in Figure 10 shows a case where the vehicle 21 enters a low-μ road surface, which is a slippery road surface, while accelerating, the drive wheels slip at time t21, and then the higher-level controller detects the slip a little later and reduces the torque command value 2.

[0068] First, focusing on the motor rotation speed 61, slippage occurs at time t21, and the rotation speed increases sharply. At this time, the estimated tire force 64 decreases sharply. This is because, due to the low friction coefficient on the low-μ surface, sufficient tire force cannot be generated. In this embodiment, the vehicle 21 is assumed to be motor-driven, and the rotation speed ω of the motor 22 m Motor torque (final torque value 7) T m , motor 22 inertia J m By using this, the estimated tire force value 64 is converted to the motor shaft torque T, as shown in equation 8. t It can be estimated as such.

[0069] J m dω m / dt = T m - T t ...(Equation 8)

[0070] This equation 8 represents the inertia J of motor 22. m and the rotation speed ω of motor 22 m The product of these is the motor torque T m and motor shaft equivalent torque T t This indicates that it is equal to the difference between the two values. Therefore, the estimated tire force value 64 immediately after slippage occurs is considered to be the maximum force that can be generated on that road surface, and in order to prevent slippage, it is essential to reduce the motor torque to at least less than that maximum tire force. In this case, by setting the symbol 82S, which is the estimated tire force value 64 immediately after slippage occurs (however converted to motor shaft torque), to a predetermined value 82, and increasing the FB gain 72 after the torque command value 2 falls below the value of symbol 82S, the effect of vibration damping control can be improved without hindering the torque reduction by traction control.

[0071] Up to this point, we have discussed the timing for starting to increase the FB gain 72. In the examples shown up to Figure 10, the FB gain 72 is increased gradually, but the rate of increase may be changed depending on the situation. Alternatively, it may be increased rapidly in steps rather than gradually. In this case, while abrupt changes in torque may induce resonance in the drive unit, the vibration damping effect due to the increase in FB gain 72 will also be improved earlier. Therefore, the rate of change should be determined by which method of increase completes the reduction of vibration during idle speed the fastest overall.

[0072] Up to this point, we have explained how to increase the FB gain 72, but we will now explain an example of how to return the FB gain 72 to its original value with reference to Figure 11. Figure 11 shows, from top to bottom, the time progression of the final torque value 7, the motor rotation speed 61, and the FB gain 72. The three figures shown in Figure 11 have the same vertical time. In this example of time progression, the vehicle 21 enters a low-friction road at some point while accelerating, the drive wheels slip at time t31, the decrease in the torque command value 2 exceeds the threshold at time t32, the FB gain 72 increases, and at time t33 the tires regain adhesion and the torque command value 2 starts increasing again.

[0073] There are at least three possible timings for reducing the FB gain 72. The first timing is when the slip information acquisition unit 5 determines tire adhesion. The second timing is when the amount of change in the motor rotation speed 61 since tire slip was determined has decreased to within a predetermined range. In Figure 11, the magnitude of the motor rotation speed 61 at the time of tire slip detection is represented by a dashed line, and the timing for restoring the FB gain 72 is when the motor rotation speed 61 returns to the value represented by the dashed line. The third timing is when a predetermined time has elapsed. This is based on the idea that if the traction control of the higher-level controller is working properly, tire slip will be suppressed once a sufficient amount of time has elapsed.

[0074] Figure 12 shows another method by which the torque correction unit 6 restores the FB gain 72. From top to bottom, Figure 12 shows the time progression of the torque command value 2, motor rotation speed 61, slip information 8, FB gain 72, and final torque value 7. The five figures shown in Figure 12 have the same vertical time. In this time progression example, at time t41, while the vehicle 21 is accelerating, the driver suddenly takes their foot off the accelerator and applies the brakes. Despite the tires being in a state of adhesion, the sudden change in motor rotation speed at that time was mistakenly judged as slippage. After time t41, the torque command value 2 decreases because the driver has taken their foot off the accelerator, satisfying the condition (threshold) for increasing the FB gain 72. Therefore, the torque correction unit 6 increases the FB gain 72 at time t42, and at time t43, it determines the error in the judgment and restores the FB gain 72 to its original value.

[0075] Thus, even when the tires are in a sticky state, if the wheelspin information acquisition unit 5 incorrectly acquires (or determines) information about wheelspin, and the torque command value 2 from the higher level decreases to a predetermined level or more, the torque correction unit 6 will increase the FB gain 72. An increase in the FB gain 72 in this situation is undesirable, but in this embodiment, it is not possible to avoid increasing the FB gain 72. Due to this increase in the FB gain 72, a torque offset occurs in a direction that hinders deceleration, as shown in the final torque value 7, during the period from time t42 to time t43 in Figure 12. Therefore, after time t42 when the FB gain 72 was increased, the torque correction unit 6 calculates the average value of the deviation between the torque command value 2 and the final torque value 7 over a predetermined period of time. If this average value exceeds a certain value, it determines that wheelspin has been misrecognized and returns the value of the FB gain 72 to its original value.

[0076] For example, if there is no error in the slippage judgment and normal control is being performed, the final torque value 7 will approximately match the torque command value 2, or will repeatedly increase and decrease around the torque command value 2. In contrast, the final torque value 7 at time t42 in Figure 12 shows a continuously widening deviation from the torque command value 2, so at time t43 the time average of the deviation exceeds the threshold, and the torque correction unit 6 judges it to be a misrecognition. Thus, if the slippage information 8 differs from the actual tire condition or differs from the slippage judgment of the higher-level controller, the torque correction unit 6 may mistakenly increase the FB gain 72, and a mechanism to correct this is necessary.

[0077] Furthermore, under similar conditions, if the higher-level controller or the actual tire condition is incorrectly determined to be "slipping" and the slipping information 8 is incorrectly determined to be "sticky," the FB gain 72 will not increase, and therefore the vibration damping effect will not improve, but interference, i.e., torque offset, is unlikely to occur. Also, if the higher-level controller or the actual tire condition is "sticky" and the slipping information 8 is "slipping," and there is no significant change in the torque command value 2 from the higher level, the FB gain 72 will similarly not increase, and the occurrence of torque offset is unlikely.

[0078] Furthermore, while Figures 11 and 12 illustrate a gradual method for reducing the FB gain 72, the rate of change may be varied depending on the situation, similar to the case of increasing the FB gain 72 as described above, and it may be reduced in steps rather than gradually.

[0079] The effects of this embodiment will be explained with reference to Figures 13 to 15. Figures 13 to 15 show the results of a simulation of torque change when slippage occurs. Figures 13 and 14 compare three configurations: one in which the FB gain 72 is not switched and the value of the FB gain 72 is kept high; one in which the FB gain 72 is reduced during the slip prevention control operation; and one in which the above-described embodiment uses a 4D observer. In Figures 13 and 14, these three are described from top to bottom as "(a) No parameter switching", "(b) Known technology", and "(c) This embodiment". Note that in "(b) Known technology", the estimated value of the motor rotation speed 61 is used as the reference rotation speed 71 of the SFC, and in "(c) This embodiment", the estimated value of the tire rotation speed 63 by the 4D observer is used as the reference rotation speed 71 of the SFC. Figure 15 compares the two of these three, excluding "(b) Known technology". First, we will explain with reference to Figures 13 and 14.

[0080] Figures 13 and 14 show the time variation during the same time period. Figure 13 focuses on the discrepancy between the torque command value 2 and the final torque value 7. In Figure 13, the torque command value 2 and the final torque value 7 in each figure are distinguished by sub-numbers a to c. In Figure 13(a), there is a discrepancy between the torque command value 2a and the final torque value 7a, as shown from 0.2 seconds onward. Therefore, the discrepancy is in the acceleration direction and may interfere with the slip prevention control. In Figure 13(b), the torque discrepancy between the torque command value 2b and the final torque value 7b is smaller than in Figure 13(a). In Figure 13(c), similar to Figure 13(b), after the change in torque command value 2c, the discrepancy between the torque command value 2c and the final torque value 7c decreases.

[0081] On the other hand, Figure 14 compares the performance of vibration damping control, focusing on the motor rotation speed 61. In Figure 14(a), the vibration damping effect is high due to the high FB gain 72, and vibration tends to decrease. On the other hand, as in the known technology shown in Figure 14(b), when the FB gain 72 is reduced during the slip prevention control operation, the vibration damping control effect is small, and vibration persists after tire slip detection. In Figure 14(c), vibration occurs from tire slip detection to the increase in FB gain 72, but then the vibration subsides after the increase in FB gain 72. Thus, this embodiment has the advantage that, after a torque change, the deviation between the final torque value 7 and the torque command value 2 is small, and vibration subsides after the parameter change.

[0082] Figure 15 shows a simulation result that differs from Figures 13 and 14, focusing on whether or not a torque offset occurs when the motor rotation speed 61 changes rapidly due to an external disturbance. As shown in Figure 15(a), the motor rotation speed 61 is shown when the driver applies the brakes and decelerates rapidly at 0.3 seconds. Figure 15(b) shows the torque command value 2b and the final torque value 7b when the FB gain 72 is fixed to a large value without switching, and it is shown that there is a discrepancy between the torque command value 2 and the final torque value 7. This discrepancy occurs in the acceleration direction (positive direction), indicating interference with the braking operation.

[0083] On the other hand, Figure 15(c) shows that when the slip information 8 correctly determines or acquires "adhesion" in the tire adhesion state, the FB gain 72 remains small, indicating that the discrepancy between the torque command value 2 and the final torque value 7 is small. Thus, the configuration of this embodiment can reduce torque offset during disturbances, i.e., interference with the higher-level controller, compared to the conventional technology.

[0084] Although Figure 15 illustrates the case where a negative disturbance occurs during deceleration, in actual use cases there are a total of four patterns depending on whether it occurs during acceleration or deceleration, and whether the disturbance is positive or negative. In all cases, the configuration in this embodiment provides the effect of having a small discrepancy between the torque command value of 2 and the final torque value of 7.

[0085] For example, if a positive disturbance such as a downhill slope occurs during acceleration, the motor rotation speed 61 increases rapidly, which in conventional technology works to reduce torque. While this does not affect safety, it may lead to discomfort for the driver. On the other hand, if a negative disturbance occurs during acceleration, such as an uphill slope, wind resistance, or braking, the torque increases in conventional technology, which may cause unintended acceleration. The configuration in this embodiment is advantageous because it minimizes such torque discrepancies. Furthermore, if a positive disturbance such as a downhill slope occurs during deceleration, conventional technology tends to decrease (increase) torque, which may cause problems such as tire lock-up on slippery surfaces. The configuration in this embodiment is advantageous because it minimizes such torque discrepancies.

[0086] In the first embodiment described above, it is possible to perform torsional resonance damping control using only the motor rotation speed 61 information, and to provide a drive control device 1 that ensures a damping effect during tire slip while preventing interference with a higher-level controller, i.e., torque offset.

[0087] According to the first embodiment described above, the following effects and advantages can be obtained. (1) The drive control device 1, which can be mounted on a vehicle 21 having a drive unit such as a motor 22 or an engine, includes a torque command acquisition unit 3 that acquires or generates a torque command value 2, a torque correction unit 6 that corrects the torque command value 2 so as to reduce resonance in the drive unit based on the motor rotation speed 61, which is the rotation speed of the controlled object, and a slip information acquisition unit 5 that acquires information on whether or not the tires are slipping. After the torque correction unit 6 acquires information on the occurrence of tire slippage from the slip information acquisition unit 5, if the magnitude of the torque command value 2 decreases, the torque correction unit 6 changes the FB gain 72, which is a parameter that determines the corrected torque 76 from the motor rotation speed 61, so as to increase the corrected torque 76.Therefore, as shown in Figures 13(c) and 14(c), it is possible to prevent torque offset while ensuring vibration damping effect during tire slip.

[0088] (2) As shown in Figures 5 and 6, the torque correction unit 6 corrects the torque command value 2 based on the difference between the reference rotational speed 71 calculated based on the torque command value 2 and the motor rotational speed 61.

[0089] (3) The torque correction unit 6 modifies the reference rotation speed 71 to reduce the steady-state error between the reference rotation speed 71 and the motor rotation speed 61, which is caused by at least one of the error between the calculation method of the reference rotation speed 71 and the behavior of the controlled object, and disturbances from the road surface that occur on the tire, as shown in Figure 6.

[0090] (4) The torque correction unit 6 changes the calculation method for the reference rotational speed 71, which is calculated based on at least one of the torque command value 2 and the motor rotational speed 61, based on whether or not the tires are slipping, as shown in Figure 6.

[0091] (5) The reference rotational speed 71 is the tire rotational speed 63 predicted by the torque command value 2 and the motor rotational speed 61.

[0092] (6) After the slippage information acquisition unit 5 has determined that the tire is slipping, the torque correction unit 6 changes the magnitude of the FB gain 72 when any of the following conditions are met: the torque command value 2 is less than or equal to a predetermined first threshold (initial value 2S minus the magnitude of the symbol 81), the rate of change of the torque command value 2 is greater than or equal to a predetermined second threshold (ratio of the initial value 2S to the magnitude of the symbol 82), or a predetermined time indicated by the symbol 83 has elapsed.

[0093] (7) The first and second thresholds are set based on the estimated value of the tire force, which is the force generated between the tire and the road surface when tire slippage is detected, i.e., the magnitude of the symbol 82S in Figure 10.

[0094] (8) The torque correction unit 6 changes the magnitude of the FB gain 72, which is a proportional gain for determining the corrected torque 76 from the motor rotation speed 61, as a parameter.

[0095] (9) The torque correction unit 6 gradually increases the magnitude of the proportional gain at a predetermined rate of change.

[0096] (10) After the torque correction unit 6 changes the FB gain 72 to increase the corrected torque 76, the slip information acquisition unit 5 determines tire adhesion, and if at least one of the following conditions is met, the amount of change in rotational speed since the tire slip was determined has decreased to within a predetermined range, a predetermined time has elapsed, or the time average value of the corrected torque 76 exceeds a predetermined value, the FB gain 72 is returned to its original value.

[0097] (11) Resonance includes torsional resonance of the drive shaft 24, which is a transmission member between the drive unit and the tire.

[0098] (12) Resonance includes resonance due to the elasticity of the motor mount 53, which is a mounting member that fixes the drive unit to the vehicle body.

[0099] —Second Embodiment— A second embodiment of the drive control device will be described with reference to Figures 16 to 19. In the following description, the same reference numerals are used for components that are the same as in the first embodiment, and the differences will be explained primarily. Points that are not specifically described are the same as in the first embodiment.

[0100] In the first embodiment described above, the torque correction unit 6 determined tire slippage using only motor rotation speed 61 information and corrected the reference rotation speed 71. This allows the drive control device 1 to use the motor rotation speed 61, which can be acquired at the highest speed and with the highest resolution, thereby exhibiting a high vibration damping effect, and is also advantageous in terms of cost and fault tolerance because it does not need to acquire other information. On the other hand, in order to more reliably solve the torque offset problem described above, vehicle information 65 may be additionally acquired from a higher-level controller, and the FB gain 72 in the present invention may be changed based on the vehicle information 65.

[0101] Figure 16 is a block diagram of the drive control device 1A in the second embodiment. The drive control device 1A includes a torque command acquisition unit 3, a rotational speed calculation unit 4, a slip information acquisition unit 5, a torque correction unit 6, and a vehicle information acquisition unit 9. The operation of the torque command acquisition unit 3 and the rotational speed calculation unit 4 is the same as in the first embodiment, so a description is omitted. The operation of the slip information acquisition unit 5 and the torque correction unit 6 is generally the same as in the first embodiment, and the differences will be explained below.

[0102] The vehicle information acquisition unit 9 acquires vehicle information 65 from the driving control device 25, which is a higher-level controller. The vehicle information 65 includes, for example, the stroke amount of the brake pedal 32 (described later) or the amount of operation (hydraulic pressure, etc.) of the brake control mechanism 33 for each wheel, the brake operation amount 62, the final torque value 7 of the other motors if the vehicle 21 is equipped with multiple motors 22, and the result of the wheel slip detection within the driving control device 25. The vehicle information 65 may also include information representing the driving state of the vehicle 21, such as the translational acceleration and rotational speed of the vehicle 21 and the tire rotation speed 63, as measured by the combine sensor 34. This information is generally acquired via CAN communication.

[0103] Referring to Figure 17, an example of the behavior of the torque correction unit 6 when acquiring the brake operation amount 62 as vehicle information 65 will be explained. Figure 17 shows an example of the time progression of the motor rotation speed 61, vehicle information 65 (brake operation amount 62), reference rotation speed 71, and final torque value 7 from top to bottom. The four figures shown in Figure 17 have the same time in the vertical direction. In Figure 17, at time t51, indicated by the dashed line, the driver applied the brakes and decelerated rapidly.

[0104] First, focusing on the motor rotation speed 61, we see that the motor rotation speed 61 decreases sharply from time t51 when the brakes are applied. At this time, the brake operation amount 62 acquired as vehicle information 65 is 0 before time t51, and then increases sharply from time t51 and converges to a constant value. This assumes that the driver is fully depressing the brake pedal 32. At this time, as shown in the figure for the reference rotation speed 71, the method of calculating the reference rotation speed 71 by the observer shown in equations 5 and 7 results in a deviation (response delay) from the actual motor rotation speed 61. Therefore, by superimposing the acquired brake operation amount 62 onto the input of equations 5 and 7, we obtain the estimated reference rotation speed 71e, which is an estimated value of the reference rotation speed 71, and becomes equivalent to the motor rotation speed 61. As a result, the final torque value 7 becomes the value indicated by sign 7e, and the discrepancy between the final torque value 7 and the torque command value 2 can be further reduced.

[0105] Referring to Figure 18, an example of the configuration of vibration damping control in the torque correction unit 6 when the tire rotation speed 63 is acquired as vehicle information 65 will be explained. Figure 18 is a block diagram of SFC (Speed ​​Difference Feedback) which multiplies the tire rotation speed 63 by a gear ratio consideration gain 75, which is the rotation speed ratio of the motor 22 and the tire 20, to obtain a reference rotation speed 71. This is a speed difference feedback method in which the tire rotation speed 63 acquired as vehicle information 65 is used directly as the reference rotation speed 71, instead of the speed difference feedback using the tire rotation speed 63 by the 4D observer in Figures 13 to 15 of the first embodiment. The tire rotation speed 63 by the 4D observer may have estimation errors and delays due to the magnitude of the observer poles and modeling errors, but by acquiring the tire rotation speed 63 as vehicle information 65, these estimation errors and delays are reduced, and higher performance vibration damping control can be achieved.

[0106] Furthermore, as vehicle information 65, wheel slip information 8e may be obtained from a higher-level controller. In this case, the wheel slip information acquisition unit 5 obtains the determination result of whether or not the tires are slipping from the driving control device 25, which is a higher-level controller, or the operating status of the traction control. The torque correction unit 6 determines the wheel slip information 8 based on these results. The wheel slip determination method based on the change in resonant frequency, as explained with reference to Figure 3, estimates wheel slip from the characteristic behavior of the motor rotation speed 61, and estimation errors and delays may occur. In contrast, higher-level controllers usually perform a more accurate tire slip determination using the tire rotation speed 63 and external information. Therefore, using the determination result of the tire slip determination in the higher-level controller as wheel slip information 8 has the advantage of making the change in FB gain 72 more reliable.

[0107] Referring to Figure 19, an example of the behavior of the torque correction unit 6 when slippage information 8e is acquired from the higher-level controller as vehicle information 65 is shown. Figure 19 shows an example of the time progression of motor rotation speed 61, vehicle information 65 (slippage information 8e from higher level), FB gain 72, torque command value 2, and final torque value 7 from top to bottom. The four figures shown in Figure 19 have the same vertical time. In Figure 19, only the figure for motor rotation speed 61 shows four dashed lines, while the other figures show only the second and fourth dashed lines. The timings shown by each dashed line are called time t61 to time t64, respectively.

[0108] The example of the time progression shown in Figure 19 illustrates that at time t61 during acceleration, the drive wheel enters a low-friction surface, causing wheelspin. A short delay later, at time t62, the higher-level controller detects the wheelspin and performs traction control (torque reduction). Subsequently, at time t63, the wheelspin subsides sufficiently and the tires regain adhesion. A short delay later, at time t64, the higher-level controller determines that adhesion has been restored, increases torque, and resumes acceleration. In reality, vibrations due to resonance would occur in the motor rotation speed 61 for a while from time t61, but these vibrations are omitted in this figure.

[0109] First, focusing on the motor rotation speed 61, at time t0 on the left edge of the diagram, the rotation speed is increasing because of acceleration. However, at time t61, slippage occurs and the rotation speed begins to increase rapidly. From time t62 onward, the rate of increase in rotation speed decreases due to slippage detection and torque reduction by the higher-level controller, and thereafter the rotation speed itself begins to decrease. At time t63, the rotation speed has decreased sufficiently and leveled off, and from time t64 onward, it increases again.

[0110] In this case, the slip information 8e from the higher-level controller detects slippage at time t62, changing its value from 0 to 1, and then changes back to 0 at time t64 when the slippage determination is completed. If this information is used as slippage information 8, the FB gain 72 gradually increases to a constant value after some time has passed since time t62 and the torque command value 2 has decreased sufficiently, and then gradually decreases back to its original value after time t64 when the slippage determination is completed. As a result, the final torque value 7 becomes an oscillatory waveform because torque correction for vibration damping control is performed while the FB gain 72 is increasing. Thus, when slippage information 8e is obtained from the higher-level controller as vehicle information 65, the increase and decrease of the FB gain 72 can be performed more reliably by using the slippage information 8e as is for slippage information 8.

[0111] In the second embodiment described above, by incorporating vehicle information 65, it becomes possible to more reliably correct the reference rotational speed 71 and to more appropriately grasp the timing of the increase and decrease of the FB gain 72. This makes it possible to provide a drive control device 1A that ensures vibration damping effect during tire slip while more reliably preventing interference with a higher-level controller, i.e., torque offset.

[0112] According to the second embodiment described above, the following effects and advantages can be obtained. (13) As shown in Figure 18, the torque correction unit 6 corrects the torque command value 2 based on the difference between the reference rotation speed 71 calculated based on the tire rotation speed 63 and the motor rotation speed 61.

[0113] (14) The drive control device 1A includes a vehicle information acquisition unit 9 that acquires at least one of the following as vehicle information 65: the rotational speed of the tire connected to the controlled object, the amount of mechanical brake acting on the tire, the drive torque of the drive control device 1A that drives the other drive wheels, and tire slippage determination information from a higher-level controller. The torque correction unit 6 corrects the reference rotational speed 71 based on the vehicle information 65.

[0114] (15) The drive control device 1A includes a vehicle information acquisition unit 9 which also functions as a tire rotation speed acquisition unit that acquires the tire rotation speed 63, which is the rotation speed of the tire connected to the controlled object. As shown in Figure 18, the torque correction unit 6 corrects the torque command value 2 based on the difference between the tire rotation speed 63 and the reference rotation speed 71.

[0115] In the first and second embodiments described above, the vehicle 21 was powered by an electric drive motor, but there are no restrictions on the power source as long as power is transmitted to the tires via a thin shaft such as a drive shaft 24. For example, the vehicle 21 could be an engine-powered car, a hybrid vehicle, construction machinery (such as a mining dump truck), or a small mobility vehicle such as a single-seater minicar. Furthermore, distributing power to the left and right wheels via the differential gear 23 is not a mandatory configuration; the vehicle could also be equipped with electric motors independently on the left and right sides, each transmitting power to the left and right wheels via a shaft.

[0116] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, parts of the configuration of each embodiment can be added, deleted, or replaced with other configurations.

[0117] Furthermore, each of the above configurations, functions, processing units, and processing means may be implemented in hardware, either partially or entirely, by designing them as integrated circuits, for example. Alternatively, each of the above configurations and functions may be implemented in software by a processor interpreting and executing programs that implement each function. Information such as programs, tables, and files that implement each function can be stored in memory, storage devices such as hard disks and SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and DVDs. Additionally, control lines and information lines are shown only if deemed necessary for explanation, and not all control lines and information lines are necessarily shown in the actual product. In practice, almost all configurations can be considered interconnected.

[0118] In the embodiments and modifications described above, the configuration of the functional blocks is merely an example. Several functional configurations shown as separate functional blocks may be integrated, or a configuration represented in one functional block diagram may be divided into two or more functions. Furthermore, some of the functions of one functional block may be provided by other functional blocks.

[0119] In the embodiments and modifications described above, the program is stored in a ROM (not shown), but the program may be stored in a rewritable, non-volatile storage device. Furthermore, the drive control device 1 may have an input / output interface (not shown), and the program may be read from another device via the input / output interface and a medium available to the drive control device 1 when needed. Here, the medium refers to, for example, a storage medium detachable from the input / output interface, or a communication medium, i.e., a wired, wireless, optical network, or a carrier wave or digital signal propagating through such a network. Also, some or all of the functions realized by the program may be realized by hardware circuits or an FPGA. [Explanation of Symbols]

[0120] 1, 1A: Drive control device 2: Torque command value 3: Torque command acquisition unit 4: Rotation speed calculation unit 5: Idle Information Acquisition Unit 6: Torque correction unit 7: Final Torque Value 8: Idle information 9: Vehicle Information Acquisition Unit 21: Vehicles 61: Motor rotation speed 63: Tire rotation speed 63e: Estimated tire rotation speed 65: Vehicle Information 71: Standard rotational speed 72: Feedback Gain

Claims

1. A drive control device that can be mounted on a vehicle having a drive unit, A torque command acquisition unit that acquires or generates torque command values, A torque correction unit that corrects the torque command value using a correction torque to reduce resonance in the drive unit based on the rotational speed of the controlled object, It includes a slip information acquisition unit that acquires information regarding whether or not the tires are slipping, The torque correction unit is a drive control device that, after acquiring information on tire slippage by the slippage information acquisition unit, changes the parameters for determining the correction torque from the rotational speed so that the correction torque increases when the magnitude of the torque command value decreases.

2. In the drive control device according to claim 1, The torque correction unit is a drive control device that corrects the torque command value based on the difference between a reference rotational speed calculated based on at least one of the torque command value and the rotational speed, and the rotational speed.

3. In the drive control device according to claim 2, The torque correction unit modifies the reference rotation speed to reduce the steady-state error between the reference rotation speed and the rotation speed, which is caused by at least one of the error between the calculation method of the reference rotation speed and the behavior of the controlled object, and disturbances from the road surface that occur on the tire.

4. In the drive control device according to claim 3, The torque correction unit is a drive control device that changes the calculation method based on whether or not the tires slip.

5. In the drive control device according to claim 2, The aforementioned reference rotational speed is the tire rotational speed predicted by the torque command value and the rotational speed, in a drive control device.

6. In the drive control device according to claim 1, The torque correction unit is a drive control device that, after the slip-slip information acquisition unit has determined that the tire is slipping, changes the parameter when any of the following conditions are met: the torque command value becomes less than or equal to a predetermined first threshold, the rate of change of the torque command value becomes greater than or equal to a predetermined second threshold, or a predetermined time has elapsed.

7. In the drive control device according to claim 6, A drive control device in which the first threshold and the second threshold are set based on an estimated value of the tire force, which is the force generated between the tire and the road surface when it is determined that the tire is slipping.

8. In the drive control device according to claim 1, The torque correction unit is a drive control device that changes the magnitude of the proportional gain for determining the correction torque from the rotational speed as the parameter.

9. In the drive control device according to claim 8, The torque correction unit is a drive control device that gradually increases the magnitude of the proportional gain at a predetermined rate of change.

10. In the drive control device according to claim 1, The torque correction unit modifies the parameters to increase the correction torque, and then, when the slipping information acquisition unit determines tire adhesion, and at least one of the following conditions is met, the amount of change in rotational speed since the determination that the tire is slipping is reduced to within a predetermined range, a predetermined time has elapsed, or the time average value of the correction torque exceeds a predetermined value, the drive control device returns the parameters to their original values.

11. In the drive control device according to claim 3, A drive control device further comprising a vehicle information acquisition unit that acquires at least one of the rotational speed, the amount of mechanical brake applied to the tire, the drive torque of a drive control device that drives other drive wheels, and tire slippage determination information in a higher-level controller as vehicle information, wherein the torque correction unit corrects the reference rotational speed based on the vehicle information.

12. In the drive control device according to claim 1, The system includes a tire rotation speed acquisition unit that acquires the tire rotation speed, which is the rotation speed of the tire connected to the control target, The torque correction unit is a drive control device that corrects the torque command value based on the difference between the tire rotation speed and the rotation speed.

13. In the drive control device according to claim 1, The aforementioned resonance includes torsional resonance of a transmission member disposed between the drive unit and the tire, in a drive control device.

14. A drive control device according to claim 1, The aforementioned resonance includes resonance due to the elasticity of the mounting member that fixes the drive unit to the vehicle, in a drive control device.

15. A drive control method performed by a drive control device that can be mounted on a vehicle having a drive unit, A torque command acquisition step that acquires or generates a torque command value, A torque correction step in which the torque command value is corrected using a correction torque to reduce resonance in the drive unit based on the rotational speed of the controlled object, This includes a step of acquiring wheel spin information to obtain information regarding whether or not the tires are spinning, In the torque correction step, after information on tire slippage is obtained in the slippage information acquisition step, the drive control method changes the parameters that determine the correction torque from the rotational speed so that the correction torque increases when the magnitude of the torque command value decreases.

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