JP2015023691A - Drive control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize improvement of steering stability and reduction of discomfort imparted to a driver by implementing slip restoration processing corresponding to a driving situation.SOLUTION: A drive control device of an electric vehicle 100 calculates an addition torque value by adding a decrement amount of a torque value in a slipping wheel (left rear wheel 108) to a torque value of a drive motor 122 of the same side non-slipping wheel (left front wheel 104), and sets a renewal torque value which is increased in a range that remains within an allowable range as the torque value of the derive motor of the same side non-slipping wheel. In a case where a first condition is satisfied, the difference between the addition torque value and the renewal torque value is subtracted from a present torque value of derive motors 120 and 124 of non-slipping side drive wheels (right front wheel 102, right rear wheel 106), and, in a case where a second condition is satisfied, the difference between the addition torque value and the renewal torque value is added to the present torque value of the derive motors of the non-slipping side drive wheels.

Description

  The present invention relates to a vehicle drive control device that controls torque of a drive motor.

  Conventionally, in an electric vehicle in which four wheels are independently driven by a motor, if any of the driving wheels slips due to freezing or water accumulation, the torque transmitted to the slipping driving wheels is reduced and the number of rotations is reduced. The early recovery from the state is aimed at. At this time, naturally, the torque of the electric vehicle as a whole is reduced. Therefore, the torque transmitted to the slipping drive wheels is reduced, and the torque of the other drive wheels is increased so that the torque of the four wheels as a whole is reduced. It is conceivable to avoid the decrease. However, if the reduced torque of the slipping drive wheel is simply applied to another drive wheel, the drive wheel with the increased torque may slip beyond the limit value of the frictional force generated on the road surface. There is.

  Therefore, in Patent Document 1, the limit value of the frictional force generated on the road surface is calculated from the estimated value of the friction coefficient of the road surface, and priority is given to the drive wheels where the generated frictional force has a large margin with respect to the limit value. A configuration for automatically allocating torque is described. Further, in Patent Document 2, for example, when one of the left and right front wheels slips, such as when the right front wheel slips, the torque of the right rear wheel increases. Is described. In this way, a new yaw moment is prevented from acting on the electric vehicle by controlling the torque.

JP 2001-177906 A JP 2005-20830 A

  For example, when the left rear wheel slips, when reducing the torque of the left rear wheel and increasing the torque of the left front wheel to compensate for the reduced torque of the left rear wheel, the limit value of the frictional force of the road surface acting on the left front wheel The torque can only be increased to a range that does not exceed. As a result, if the torque reduction cannot be compensated for, a decrease in torque can be avoided by increasing the torque of the right and left front wheels, but in this case, a new yaw moment acts on the electric vehicle. Therefore, it is necessary to cancel the generated yaw moment by steering. For example, when traveling at high speed, traveling control by steering is not easy, and the operability is lowered.

  On the other hand, if the right and left front and rear wheel torques are balanced by reducing the right and left front and rear wheel torques instead of increasing the right and left front and rear wheel torques, a new yaw moment will not act on the electric vehicle, and the control Improved safety. However, in this case, the torque of the four wheels as a whole is lowered, and, for example, the acceleration performance is lowered during acceleration, causing the driver to feel uncomfortable.

  Accordingly, an object of the present invention is to provide a vehicle drive control device capable of realizing improvement of operability and reduction of uncomfortable feeling given to a driver by performing slip recovery processing according to driving conditions. To do.

  In order to solve the above-described problems, a drive control device for a vehicle according to the present invention includes four drive motors that independently drive four drive wheels disposed on the front, rear, left, and right of the vehicle, and each drive motor. A drive control device for a vehicle, comprising: a resistance value deriving unit for deriving a road surface resistance value from input information input while the vehicle is running; and a resistance value Based on the road surface resistance value derived by the deriving unit, an allowable range deriving unit for deriving an allowable range of the torque value of each drive motor, and determining whether each drive wheel has a slip wheel in an over-rotation state If the slip wheel determination unit and the slip wheel determination unit determine that there is a slip wheel in an over-rotation state, the torque value of the drive motor for the slip wheel is set to a torque value smaller than the torque value before the determination. Slip The torque value setting unit and the decrease in the torque value in the slip wheel are added to the torque value of the drive motor of the same non-slip wheel, which is the drive wheel arranged in front of or behind the slip wheel, and the added torque value is obtained. An additional torque value calculation unit to be calculated, an allowance determination unit that determines whether the additional torque value calculated by the additional torque value calculation unit is within an allowable range of the torque value in the drive motor of the same non-slip wheel, When the determination unit determines that the additional torque value is within the allowable range of the torque value of the drive motor for the same non-slip wheel, the additional torque value is determined as the torque value of the drive motor for the same non-slip wheel. When it is determined that the added torque value is not within the allowable range of the torque value of the drive motor of the non-slip wheel on the same side, the torque value is increased within the allowable range. When the new torque value is set as the torque value of the drive motor of the same side non-slip wheel, and when the updated torque value is set as the torque value of the drive motor of the same side non-slip wheel A non-slip side torque value setting unit for setting a torque value of one or both of a drive wheel that makes a left-right pair with a slip wheel, and a drive wheel that makes a left-right pair with a non-slip wheel on the same side; And the non-slip side torque value setting unit determines whether the first condition set in advance is satisfied, and if it is determined that the first condition is satisfied, the additional torque is determined from the torque value of the current drive motor. When the torque value obtained by subtracting the difference between the value and the update torque value is set and the second condition preset as the first condition and the exclusive condition is satisfied, the torque value of the current drive motor is Addition Toll A torque value to which a difference between the torque value and the updated torque value is added is set.

  The first condition includes that the vehicle speed is equal to or higher than a predetermined vehicle speed, and the second condition may include that the vehicle speed is lower than the predetermined vehicle speed.

  The non-slip side torque value setting unit determines that the first condition is satisfied when the vehicle speed is equal to or higher than the first threshold, and calculates a difference between the added torque value and the updated torque value from the current torque value of the drive motor. Is set, and when the vehicle speed is less than the second threshold value, which is lower than the first threshold value, it is determined that the second condition is satisfied, and is added to the current drive motor torque value. You may set the torque value which added the difference of a torque value and an update torque value.

  The non-slip side torque value setting unit may set the torque value according to the vehicle speed when the vehicle speed is less than the first threshold and greater than or equal to the second threshold.

  The first condition may include that the road surface resistance value is less than a predetermined value, and the second condition may include that the road surface resistance value is greater than or equal to a predetermined value.

  A non-slip side torque value setting unit, comprising: a travel mode setting unit for setting any one of a plurality of travel modes including a first travel mode and a second travel mode that have at least different torque value setting conditions; Determines that the first condition is satisfied when the first driving mode is set by the driving mode setting unit, and the second condition is satisfied when the second driving mode is set by the driving mode setting unit. May be determined.

  The travel mode setting unit may set the travel mode according to the operation of the driver.

  According to the present invention, it is possible to improve the operability and reduce the uncomfortable feeling given to the driver by performing the slip recovery process according to the driving situation.

It is a figure which shows the structure of an electric vehicle. It is a 1st figure for demonstrating the slip reset process by a drive control apparatus. It is a 2nd figure for demonstrating the slip reset process by a drive control apparatus. It is explanatory drawing for demonstrating the performance conditions of a subtraction setting process and an addition setting process. It is a flowchart which shows the flow of a torque control process. It is a flowchart which shows the flow of a non-slip side torque setting process. It is a figure which shows the structure of the electric vehicle in a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a diagram illustrating a configuration of an electric vehicle 100 (vehicle). As shown in FIG. 1, in an electric vehicle 100, a right front wheel 102, a left front wheel 104, a right rear wheel 106, and a left rear wheel 108 are connected to a drive motor 120 via gears in gear boxes 112, 114, 116, and 118, respectively. , 122, 124, 126. The drive motors 120, 122, 124, and 126 are connected to the battery 136 via inverters 128, 130, 132, and 134, respectively, are rotated by the power supplied from the battery 136, and are obtained by generating power. Is sent to the battery 136. In the electric vehicle 100, the right front wheel 102, the left front wheel 104, the right rear wheel 106, and the left rear wheel 108 are independently driven by driving (rotating) the drive motors 120, 122, 124, and 126 independently. To do.

  The battery 136 is connected to the battery controller 138 and controlled by the battery controller 138. The battery controller 138 is connected to the drive control device 140, monitors the charge / discharge current amount, temperature, and the like of the battery 136, calculates the remaining capacity of the battery 136 based on the charge / discharge current amount, and stores data relating to the battery 136. It outputs to the drive control apparatus 140 as needed.

  The drive control device 140 is a microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and comprehensively controls each unit. The drive control device 140 is connected to each of the wheel rotational speed sensors 142, 144, 146, 148, the accelerator pedal sensor 150, the handle sensor 152, the shift sensor 154, the acceleration sensor 156, and the yaw rate sensor 158, and each sensor (142-158). A signal indicating the value detected in is input. Further, the drive control device 140 is connected to the inverters 128, 130, 132, and 134, and as will be described in detail later, based on signals input from the sensors (142 to 158), the inverters 128, 130, The drive of the drive motors 120, 122, 124, 126 is controlled via 132, 134.

  The wheel rotation speed sensors 142, 144, 146, and 148 are, for example, resolvers, detect the rotation speeds of the right front wheel 102, the left front wheel 104, the right rear wheel 106, and the left rear wheel 108, and drive signals indicating the rotation speeds. Output to the control device 140.

  The accelerator pedal sensor 150 detects the depression amount of the accelerator pedal and outputs a signal indicating the depression amount to the drive control device 140.

  The handle sensor 152 detects the rotation angle of the handle and outputs a signal indicating the rotation angle to the drive control device 140.

  The shift sensor 154 detects the shift position (neutral, drive, back, etc.) inserted by the shift lever, and outputs a signal indicating the shift position to the drive control device 140.

  The acceleration sensor 156 detects the acceleration of the electric vehicle 100 and outputs a signal indicating the acceleration to the drive control device 140.

  The yaw rate sensor 158 detects the yaw rate of the electric vehicle 100 and outputs a signal indicating the yaw rate to the drive control device 140.

  The drive control device 140 acquires signals from the wheel rotation number sensors 142, 144, 146, 148, the accelerator pedal sensor 150, and the handle sensor 152 at predetermined intervals, respectively. When the shift sensor 154 detects that the shift lever is in the drive shift position and a signal indicating the shift position is input to the drive control device 140, the drive control processing of the drive motors 120, 122, 124, 126 is performed. Run.

  When a signal indicating the drive shift position is input, the drive control device 140 expands the drive control processing program stored in the ROM to the RAM and executes the drive control processing, and the drive motors 120, 122, 124, 126. Is controlled. When the drive control device 140 performs drive control of the drive motors 120, 122, 124, and 126, the torque control unit 200, the resistance value deriving unit 202, the allowable range deriving unit 204, the slip wheel determining unit 206, and the slip wheel torque value determining Unit 208, additional torque value calculation unit 210, tolerance determination unit 212, non-slip wheel torque value setting unit 214, and non-slip side torque value setting unit 216.

  The torque control unit 200 calculates an average value of the rotation speeds of the right front wheel 102 and the left front wheel 104. Then, the torque control unit 200 calculates the vehicle speed of the electric vehicle 100 based on the calculated average value. Since the front wheels (the right front wheel 102 and the left front wheel 104) are relatively less likely to slip than the rear wheels (the right rear wheel 106 and the left rear wheel 108), the vehicle speed is calculated by calculating the vehicle speed from the average value of the rotation speed of the front wheels. Accuracy is improved. Further, the torque control unit 200 determines the vehicle speed based on the second or third largest rotational speed among the rotational speeds of the driving wheels of the right front wheel 102, the left front wheel 104, the right rear wheel 106, and the left rear wheel 108. May be calculated. Further, the torque control unit 200 may calculate the vehicle speed based on the number of rotations of drive wheels other than the drive wheel determined by a slip wheel determination unit 206 described later as a slip wheel.

  The torque control unit 200 determines the required power to be output from the drive motors 120, 122, 124, 126 based on the output rotation speed map stored in advance in the ROM based on the accelerator pedal depression amount and the vehicle speed, and the drive motors 120, 122. , 124, 126 are determined. Then, the torque control unit 200 calculates a target torque value, which is a torque value to be output by the drive motors 120, 122, 124, 126, from the determined required power and the target rotational speeds of the drive motors 120, 122, 124, 126. To do.

  Then, the torque control unit 200 controls the inverters 128, 130, 132, and 134 to drive the drive motors 120, 122, 124, and 126 with the calculated target torque value. As a result, the drive motors 120, 122, 124, 126 are driven at the target torque values via the inverters 128, 130, 132, 134.

  The resistance value deriving unit 202 derives a road surface friction coefficient (μ estimated value) that is a road surface resistance value from input information input while the electric vehicle 100 is traveling. About the estimation method of (mu) estimated value, it is disclosed by various existing literatures, for example, Unexamined-Japanese-Patent No. 2008-168877 etc. of the same applicant.

  The estimation method of this μ estimated value will be briefly described. Adaptive control using unknown parameters such as an equivalent cornering power of a drive wheel based on an equation of motion related to the translational motion of the electric vehicle 100 and an equation of motion related to the rotational motion of the electric vehicle 100. To derive the value of the parameter. Then, based on the parameter estimated by the change in the yaw rate of the driving wheel and the parameter estimated by the rotation angle of the steering wheel, the cornering power on the front wheel (right front wheel 102, left front wheel 104) side of the driving wheel, The cornering power on the rear wheels (right rear wheel 106, left rear wheel 108) side is estimated. Then, the μ estimated value is derived from the ratio between the estimated cornering power and the reference equivalent cornering power that is equivalent cornering power on the road surface having a high road surface friction coefficient.

  The allowable range deriving unit 204 derives the allowable range of the target torque value of each of the drive motors 120, 122, 124, 126 based on the μ estimated value derived by the resistance value deriving unit 202. Specifically, the permissible range deriving unit 204 derives the vertical drag of the road surface from the load acting on the road surface from the driving wheel, and derives the maximum value of the frictional force generated on the road surface by the μ estimated value and the normal force. Then, the allowable range deriving unit 204 derives an allowable range of the target torque value based on the maximum value of the frictional force and the outer diameter of the drive wheel. During normal times (when no slip has occurred in any of the drive wheels), the torque control unit 200 generates slip by correcting the target torque value so as not to exceed the allowable range of the derived target torque value. Is suppressed.

  Even if the target torque value is corrected as described above, the slip cannot be completely avoided. For example, it is assumed that any one of four drive wheels rides on a road surface having a low coefficient of friction such as a frozen road surface. At this time, if the vehicle speed is not derived using the rotational speed of the driving wheel on the road surface with a low friction coefficient, the influence of the road surface with a low friction coefficient is not reflected in the μ estimated value, and the road friction coefficient is a high value. It is determined. Then, the allowable range of the target torque value derived by the allowable range deriving unit 204 becomes a value larger than the actual value, and a slip may occur.

  If any of the driving wheels of the right front wheel 102, the left front wheel 104, the right rear wheel 106, and the left rear wheel 108 slips, the drive control device 140 reduces the torque transmitted to the slipping driving wheel and reduces the rotation speed. Thus, an early return from the slip state is attempted (slip return processing). At this time, the drive control device 140 corrects the target torque values of the drive motors 120, 122, 124, 126 connected to the non-slip drive wheels, thereby improving the operability and giving the driver a sense of discomfort. Reduction is possible.

  FIG. 2 is a first diagram for explaining slip recovery processing by the drive control device 140, and FIG. 3 is a second diagram for explaining slip recovery processing by the drive control device 140. 2 and 3, white arrows and black arrows indicate the forces that the driving wheels act on the road surface in the surface direction of the road surface. As shown in FIG. 2A, the electric vehicle 100 travels while turning to the left, and the torque control unit 200 drives the drive motors 120, 122, 124, and 126 at the target torque value.

  As shown in FIG. 2B, it is assumed that, for example, the left rear wheel 108 rides and slips on a road surface having a low friction coefficient (low friction road surface W) such as a frozen road surface.

  The slip wheel determination unit 206 determines whether or not there is a slip wheel in an over-rotation state among the drive wheels. Since the slipping drive wheel rapidly rotates due to idling, the slip wheel determination unit 206 uses the rotation speeds of the drive motors 120, 122, 124, and 126 to drive the right front wheel 102, the left front wheel 104, and the right rear wheel. It is detected whether the driving wheel of the wheel 106 or the left rear wheel 108 is slipping. Here, the left rear wheel 108 is detected as a slipping wheel slipping.

  When the slip wheel determination unit 206 determines that there is a slip wheel in an over-rotation state, the slip wheel torque value determination unit 208 determines target torque values of the drive motors 120, 122, 124, and 126 for the slip wheel. Set to a value smaller than the previous target torque value. Here, the target torque value of the drive motor 126 of the left rear wheel 108 is corrected to a value smaller than the target torque value before determination. Then, as shown in FIG. 2B, the force that the left rear wheel 108 acts on the road surface in the surface direction of the road surface is reduced, and the return of the left rear wheel 108 from the slip state is accelerated.

  The additional torque value calculation unit 210 uses the drive motors 120, 122, 124 of the same non-slip wheel, which is a drive wheel arranged in front of or behind the slip wheel, to decrease the target torque value in the slip wheel. The added torque value is calculated by adding to the target torque value of 126. Here, as shown in FIG. 2C, the left front wheel 104 is selected as the non-slip wheel on the same side, and the target torque value of the drive motor 122 of the left front wheel 104 is reduced by the target torque value of the left rear wheel 108. Are added (indicated by a solid arrow in FIG. 2C), and an added torque value is calculated.

  The allowance determining unit 212 determines whether or not the added torque value calculated by the added torque value calculating unit 210 is within the allowable range of the target torque value in the drive motors 120, 122, 124, and 126 of the same non-slip wheel. judge. Here, for the left front wheel 104, it is determined whether or not the added torque value is within the allowable range of the target torque value derived by the allowable range deriving unit 204.

  The friction circle indicated by the alternate long and short dash line in FIG. 2C indicates the allowable range of the target torque value derived by the allowable range deriving unit 204. The frictional force acting on the driving wheel from the road surface can be any direction of the surface of the road surface around the driving wheel depending on the direction of the load acting on the road surface from the driving wheel. The allowable range of the torque value is indicated by a friction circle. Here, in order to facilitate understanding, among the loads acting in the plane direction of the road surface from the driving wheel to the road surface, the load in the left-right direction of the electric vehicle 100 is not considered, and the load is only in the rear direction of the electric vehicle 100. Is acting.

  The same-side non-slip wheel torque value setting unit 214 determines that the added torque value is within the allowable range of torque values in the drive motors 120, 122, 124, 126 of the same-side non-slip wheel by the allowance determining unit 212. In this case, the added torque value is set as the target torque value of the drive motors 120, 122, 124, 126 for the same non-slip wheel.

  FIG. 2C shows an example of the case where the additional torque value is within the allowable range of the target torque value (within the range of the friction circle) for the left front wheel 104. In such a case, the same-side non-slip wheel torque value setting unit 214 sets the added torque value as it is as the target torque value of the drive motor 122 for the left front wheel 104.

  On the other hand, in the example shown in FIG. 2D, the allowable range of the target torque value of the drive motor 122 of the left front wheel 104 (friction circle indicated by the alternate long and short dash line in FIG. 2D) is greater than that in FIG. The left front wheel 104 is small, and the added torque value is outside the allowable range of the target torque value (out of the range of the friction circle).

  When the same-side non-slip wheel torque value setting unit 214 determines that the added torque value is not within the allowable range of the target torque values of the drive motors 120, 122, 124, 126 of the same-side non-slip wheel. Then, the updated torque value obtained by increasing the torque value within the allowable range is set as the target torque value of the drive motors 120, 122, 124, 126 for the same non-slip wheel.

  Here, as shown in FIG. 3A, an updated torque value obtained by increasing the torque value within the allowable range is set as the target torque value of the drive motor 122 of the left front wheel 104.

  When the updated torque value is set as the target torque value of the drive motors 120, 122, 124, 126 of the same non-slip wheel, the non-slip side torque value setting unit 216, The target torque values 122, 124 and 126 are set. Here, the non-slip side driving wheel indicates a driving wheel that makes a left-right pair with the slip wheel, and a driving wheel that makes a left-right pair with the same-side non-slip wheel.

  In the example illustrated in FIG. 3, the non-slip side torque value setting unit 216 targets any one of the non-slip side drive wheels (the right front wheel 102 and the right rear wheel 106). Then, the non-slip side torque value setting unit 216 adds a torque difference value that is a difference between the addition torque value of the drive motor 122 of the left front wheel 104 and the update torque value to the target torque value of the target drive motors 120 and 124. Or subtract.

  In the example shown in FIG. 3A, the torque difference value is subtracted from the target torque value of the drive motor 120 for the right front wheel 102, and in the example shown in FIG. 3B, the target torque value of the drive motor 120 for the right front wheel 102. The torque difference value is added to 3C, the torque difference value is subtracted from the target torque value of the drive motor 124 for the right rear wheel 106. In the example shown in FIG. 3D, the drive motor 124 for the right rear wheel 106. The torque difference value is added to the target torque value.

  As shown in FIGS. 3A and 3C, the torque difference value is subtracted from the current target torque value of the drive motor 120 of the right front wheel 102 and the current target torque value of the drive motor 124 of the right rear wheel 106. Then (hereinafter referred to as the subtraction setting process), the torques of the left and right drive wheels can be balanced. Therefore, a new yaw moment does not act on the electric vehicle 100, and the maneuverability is improved. However, in this case, the torque of the four drive wheels as a whole decreases, and the driver feels uncomfortable, for example, the acceleration performance decreases during acceleration.

  On the other hand, as shown in FIGS. 3B and 3D, a torque difference value is added to the current target torque value of the drive motor 120 of the right front wheel 102 and the current target torque value of the drive motor 124 of the right rear wheel 106. Is added (hereinafter referred to as addition setting processing), a new yaw moment acts on the electric vehicle 100. Therefore, it is necessary to cancel the generated yaw moment by steering. For example, when traveling at high speed, traveling control by steering is not easy, and the operability is lowered.

  Therefore, the non-slip side torque value setting unit 216 selects and executes a subtraction setting process or an addition setting process according to a preset performance condition.

  FIG. 4 is an explanatory diagram for explaining the performance conditions of the subtraction setting process and the addition setting process. FIG. 4A shows a low friction state in which the μ estimated value is less than a predetermined threshold (for example, 0.5). FIG. 4B shows performance conditions in a high friction state in which the μ estimated value is equal to or greater than a predetermined threshold value.

  In addition to the two driving modes, a sports mode (first driving mode) that prioritizes acceleration and the like, and a normal mode (second driving mode) that prioritizes maneuverability, the electric vehicle 100 can arbitrarily set the characteristics of both driving modes. It is possible to set a transition mode integrated with the selection ratio. In FIG. 4, the legend a indicates the selection ratio of the sport mode, and the legend b indicates the selection ratio of the normal mode.

  Further, the non-slip side torque value setting unit 216 divides, according to the μ estimated value, into two states: a low friction state where the μ estimated value is less than a predetermined threshold value, and a high friction state where the μ estimated value is equal to or greater than the predetermined threshold value. Thus, the driving mode is set using a different threshold value for each state.

When the vehicle speed is equal to or higher than the first threshold value (V ₁ in FIG. 4A) in the low friction state, the normal mode selection ratio is 100% and the sports mode selection ratio is 0%. That is, the traveling mode is set to the normal mode. When the vehicle speed is less than the second threshold value (V ₂ in FIG. 4A) which is lower than the first threshold value, the normal mode selection ratio is 0% and the sports mode selection ratio is 100%. . That is, the travel mode is set to the sport mode.

  The non-slip side torque value setting unit 216 determines whether a first condition set in advance is satisfied, and performs a subtraction setting process when determining that the first condition is satisfied. The non-slip side torque value setting unit 216 performs addition setting processing when a second condition preset as a condition exclusive of the first condition is satisfied.

Specifically, the non-slip side torque value setting unit 216, if the vehicle speed is smaller than the first threshold value (V ₁ or higher), i.e., it is determined that satisfies the first condition when a normal mode, Perform subtraction setting processing. The non-slip side torque value setting unit 216, when the vehicle speed is less than the second threshold value (less than V _2), i.e., it is determined that satisfies the second condition when a sport mode, the addition setting processing I do.

  That is, the first condition includes that the vehicle speed of the electric vehicle 100 is equal to or higher than the predetermined vehicle speed, and the second condition includes that the vehicle speed of the electric vehicle 100 is less than the predetermined vehicle speed. It is.

  In this way, by selecting and performing the subtraction setting process or the addition setting process in accordance with preset performance conditions, slip recovery processing is performed according to the driving situation, improving the operability and giving the driver a sense of incongruity Can be reduced.

  In addition, the subtraction setting process is performed when the vehicle speed is higher than the predetermined vehicle speed, and the addition setting process is performed when the vehicle speed is lower than the predetermined vehicle speed. When the vehicle speed is low and acceleration is important, it is possible to suppress a decrease in torque of the entire drive wheel.

  In addition, by setting the second threshold value to be a value lower than the first threshold value instead of the same value as the first threshold value, a transition section is provided between the normal mode and the sport mode, and both the normal mode and the sport mode are complete. It is possible to increase the degree of freedom of control processing such as performing control that is not the same.

Here, the non-slip side torque value setting unit 216, the vehicle speed is less than the first threshold value (V less than _1), and, if it is smaller than the second threshold value (V ₂ or more) (if a transition mode), the vehicle speed The target torque value is set according to

As shown in FIG. 4A, the selection ratio of the sport mode shown in the legend a is proportionally decreased with respect to the vehicle speed from the second threshold value to the first threshold value, and the selection ratio of the normal mode shown in the legend b is proportional. Increase. Specifically, the selection ratio N in the normal mode is calculated by (V−V ₂ ) / (V ₁ −V ₂ ) where the current vehicle speed is the vehicle speed V. Further, the selection ratio S of the sport mode is calculated by 1-N.

  The non-slip side torque value setting unit 216 multiplies the target torque value calculated by the subtraction setting process when the normal mode selection ratio is 100% by the normal mode selection ratio N according to the vehicle speed. Further, the non-slip side torque value setting unit 216 multiplies the target torque value calculated by the addition setting process when the sport mode selection ratio is 100% by the sport mode selection ratio S corresponding to the vehicle speed. Then, the sum of both multiplication results is set as a new target torque value (ratio setting process).

  Thus, in the transition mode, by setting the target torque value according to the vehicle speed, even if the vehicle speed is between the second threshold value and the first threshold value, it is possible to perform the slip recovery process appropriately corresponding to the driving situation. It becomes.

Further, as shown in FIG. 4B, in the high friction state where the μ estimated value is equal to or greater than the predetermined threshold, the first threshold (V ₃ ) is lower than the first threshold (V ₁ ) in the low friction state. The second threshold value (V ₄ ) is set lower than the second threshold value (V ₂ ) in the low friction state.

  Since the road surface is difficult to slip in the high friction state, the first threshold value and the second threshold value are set so that the sport mode is selected (the selection ratio is increased) even at a higher vehicle speed. In this way, by selectively using the first threshold value and the second threshold value in accordance with the μ estimated value, it is possible to perform the slip recovery process appropriately corresponding to the driving situation.

  FIG. 5 is a flowchart showing the flow of torque control processing. As shown in FIG. 5, the slip wheel determination unit 206 determines whether or not there is a slip wheel in an over-rotation state among the drive wheels (S300). When there is no slip ring (NO in S300), the torque control unit 200 performs a normal torque control process (S302). Then, the process returns to the slip determination process step S300.

  When it is determined that there is a slip ring (YES in S300), the allowable range deriving unit 204 acquires the μ estimated value derived by the resistance value deriving unit 202 (S304), and based on the acquired μ estimated value, An allowable range of the target torque value of the drive motors 120, 122, 124, 126 is derived (S306).

  The slip wheel torque value determination unit 208 sets the target torque value of the drive motor 120, 122, 124, 126 of the slip wheel to a value smaller than the target torque value before determination (S308). The additional torque value calculation unit 210 calculates the additional torque value by adding the decrease of the target torque value in the slip wheel to the target torque value of the drive motors 120, 122, 124, 126 of the same non-slip wheel (S310). ).

  In the allowance determining unit 212, the added torque value calculated by the added torque value calculating unit 210 is within the allowable range (friction circle) of the target torque value in the drive motors 120, 122, 124, 126 of the same non-slip wheel. It is determined whether or not (S312). If within the allowable range (YES in S312), the same-side non-slip wheel torque value setting unit 214 sets the added torque value as the target torque value of the drive motors 120, 122, 124, 126 for the same-side non-slip wheel. (S314). The torque control unit 200 drives the drive motors 120, 122, 124, 126 based on the set target torque value (S316).

  When the added torque value is not within the allowable range of the target torque value (NO in S312), the same-side non-slip wheel torque value setting unit 214 increases the updated torque value by increasing the torque value within the allowable range. It is set as the target torque value of the drive motor 120, 122, 124, 126 for the same non-slip wheel (S318).

  Subsequently, the non-slip side torque value setting unit 216 drives the non-slip side drive wheel when the updated torque value is set as the target torque value of the drive motor 120, 122, 124, 126 of the same side non-slip wheel. The target torque values of the motors 120, 122, 124, 126 are set (S320). The processing flow of the non-slip side torque setting processing step S320 will be described later.

  The torque control unit 200 drives the drive motors 120, 122, 124, 126 based on the set target torque value (S322).

  FIG. 6 is a flowchart showing the flow of the non-slip side torque setting processing step S320. As shown in FIG. 6, the non-slip side torque value setting unit 216 determines whether or not the μ estimated value is less than a predetermined threshold (for example, 0.5) (S350). The non-slip side torque value setting unit 216 determines that the road surface is in a low friction state (S352) when the μ estimated value is less than the predetermined threshold (YES in S350), and when the μ estimated value is equal to or larger than the predetermined threshold (S350). NO), the road surface is determined to be in a high friction state (S354).

  Then, the non-slip side torque value setting unit 216 determines whether or not the vehicle speed is equal to or higher than the first threshold value in the determined friction state (S356). When the vehicle speed is equal to or higher than the first threshold (YES in S356), non-slip side torque value setting unit 216 selects the normal mode as the travel mode (S358). Subsequently, the non-slip side torque value setting unit 216 performs a subtraction setting process (S360). Specifically, the torque difference value, which is the difference between the added torque value calculated in the added torque value calculating step S310 and the updated torque value set in the updated torque value setting step S318, is used as the drive motor 120 for the non-slip drive wheels. , 122, 124, 126 are subtracted from the target torque values. Then, the non-slip side torque setting process ends.

  If the vehicle speed is less than the first threshold (NO in S356), the non-slip side torque value setting unit 216 determines whether the vehicle speed is less than the second threshold in the selected friction mode (S362). . When the vehicle speed is less than the second threshold (YES in S362), the non-slip side torque value setting unit 216 selects the sport mode as the travel mode (S364), and performs an addition setting process (S366). Specifically, the non-slip side torque value setting unit 216 calculates a torque difference value that is a difference between the addition torque value calculated in the addition torque value calculation step S310 and the update torque value set in the update torque value setting step S318. The target torque value of the drive motors 120, 122, 124, 126 of the non-slip drive wheels is added. Then, the non-slip side torque setting process ends.

  When the vehicle speed is equal to or higher than the second threshold value (NO in S362), the non-slip side torque value setting unit 216 derives the sport mode selection ratio S and the normal mode selection ratio N according to the vehicle speed (S368). ), The ratio setting process described above is performed (S370). Then, the non-slip side torque setting process ends.

  As described above, the drive control device 140 can improve the operability and reduce the uncomfortable feeling given to the driver by performing the slip recovery process according to the driving situation.

(Modification)
FIG. 7 is a diagram showing a configuration of an electric vehicle 400 in a modified example. The electric vehicle 400 according to the modification differs from the above-described embodiment only in the operation unit 460 and the drive control device 440. The description of the same configuration as that of the above-described embodiment is omitted, and only the operation unit 460 and the drive control device 440 having different configurations will be described.

  The operation unit 460 receives a driver's operation input for setting the travel mode, and outputs it to the drive control device 440.

  The drive control device 440 is connected to the operation unit 460 in addition to the sensors (142 to 158) described above, and receives a signal indicating a value detected by the operation unit 460.

  Further, when the drive control device 440 performs drive control of the drive motors 120, 122, 124, 126, the torque control unit 200, the resistance value deriving unit 202, the allowable range deriving unit 204, the slip wheel determining unit 206, and the slip wheel torque. It functions as a value determination unit 208, an added torque value calculation unit 210, an allowance determination unit 212, a same-side non-slip wheel torque value setting unit 214, a non-slip side torque value setting unit 416, and a travel mode setting unit 418. Since these functional units are different from the above-described embodiment only in the non-slip side torque value setting unit 416 and the travel mode setting unit 418, the non-slip side torque value setting unit 416 and the travel mode setting unit 418 are described. explain.

  The travel mode setting unit 418 sets one of the travel modes from among a plurality of travel modes including the normal mode and the sport mode in accordance with the driver's operation on the operation unit 460.

  The non-slip side torque value setting unit 416 determines that the first condition is satisfied when the normal mode is set by the travel mode setting unit 418 and the non-slip side torque value setting unit 416 is set to the sports mode by the travel mode setting unit 418. It is determined that the second condition is satisfied.

  The non-slip side torque value setting unit 416 performs subtraction setting processing when the first condition is satisfied. The non-slip side torque value setting unit 416 performs addition setting processing when the second condition is satisfied.

  As described above, by performing the subtraction setting process or the addition setting process according to the travel mode, it is possible to correct the target torque value based on various conditions without being limited to the vehicle speed. In addition, since the driving mode is set according to the operation of the driver by the operation unit 460, the driver's intention is reflected in the setting of the driving mode, and the slipping according to the driving situation and in accordance with the driver's intention. Return processing can be performed.

  In the above-described embodiment, the case where the normal mode is set when the vehicle speed is equal to or higher than the first threshold and the sport mode is set when the vehicle speed is lower than the second threshold smaller than the first threshold is described. For example, using one threshold, the normal mode may be set when the vehicle speed is equal to or higher than the third threshold, and the sport mode may be set when the vehicle speed is lower than the third threshold.

  In the embodiment described above, the first condition includes that the vehicle speed is equal to or higher than the predetermined vehicle speed, and the second condition includes that the vehicle speed is less than the predetermined vehicle speed. Explained the case. However, the first condition may include that the μ estimated value is less than a predetermined value, and the second condition may include that the μ estimated value is greater than or equal to a predetermined value. When the first condition is satisfied, the subtraction setting process is performed, and when the second condition is satisfied, the addition setting process is performed. In this case, when the estimated value of μ is low and stability is important, the generation of a new yaw moment is suppressed, and when the estimated value of μ is high and acceleration is important, the torque reduction of the entire drive wheel is suppressed. Is possible.

  In addition, the parameters included in the first condition and the second condition are not limited to the vehicle speed and the μ estimated value, but may be, for example, the accelerator opening, or the position information of the electric vehicle 100 acquired from the car navigation system or the like. The first condition and the second condition may be set. Further, the first condition and the second condition regarding the information on the outside environment acquired from the outside environment recognition device that detects a specific object such as a vehicle or a traffic light located in front of the host vehicle and performs collision avoidance control or inter-vehicle distance control. May be set.

  In the above-described embodiment, the case where the torque difference value is added to or subtracted from the target torque value of any one of the drive motors 120, 122, 124, 126 of the two non-slip drive wheels is described. did. However, the torque difference value may be distributed to the drive motors 120, 122, 124, 126 of the two non-slip drive wheels, and the distributed value may be added to or subtracted from each target torque value.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  The present invention can be used for a vehicle drive control device for controlling the torque of a drive motor.

100, 400 Electric car (vehicle)
102 Front right wheel (drive wheel)
104 Front left wheel (drive wheel)
106 Right rear wheel (drive wheel)
108 Left rear wheel (drive wheel)
120, 122, 124, 126 Drive motor 140, 440 Drive control device 200 Torque control unit 202 Resistance value deriving unit 204 Tolerable range deriving unit 206 Slip wheel determining unit 208 Slip wheel torque value determining unit 210 Additional torque value calculating unit 212 Allowable determination 214 Non-slip wheel torque value setting unit 216, 416 Non-slip torque value setting unit 418 Travel mode setting unit

Claims (7)

A vehicle comprising: four drive motors that independently drive four drive wheels arranged on the front, rear, left, and right sides of the vehicle; and a torque control unit that controls each drive motor based on a set torque value. A drive control device comprising:
A resistance value deriving unit for deriving a road surface resistance value from input information input during travel of the vehicle;
An allowable range deriving unit for deriving an allowable range of the torque value of each drive motor based on the road surface resistance value derived by the resistance value deriving unit;
A slip wheel determination unit for determining whether there is a slip wheel in an overspeed state in each drive wheel;
If the slip wheel determination unit determines that there is a slip wheel in an over-rotation state, the slip wheel torque that sets the torque value of the drive motor of the slip wheel to a torque value smaller than the torque value before the determination A value setting section;
The amount of decrease in the torque value of the slip wheel is added to the torque value of the drive motor of the same non-slip wheel, which is the drive wheel disposed on the front or rear side of the slip wheel, to calculate the added torque value. An additional torque value calculation unit;
An allowance determining unit that determines whether the added torque value calculated by the added torque value calculating unit is within an allowable range of a torque value in the drive motor of the same non-slip wheel;
When the allowable determination unit determines that the additional torque value is within the allowable range of the torque value in the drive motor of the same-side non-slip wheel, the additional torque value is set to the same-side non-slip wheel. When it is determined that the added torque value is not within the allowable range of the torque value of the drive motor of the non-slip wheel on the same side, the range that falls within the allowable range The same side non-slip wheel torque value setting unit that sets the updated torque value obtained by increasing the torque value in step S3 as the torque value of the drive motor of the same side non-slip wheel;
When the updated torque value is set as the torque value of the drive motor for the non-slip wheel on the same side, a drive wheel that forms a left-right pair with the slip wheel, and a drive wheel that forms a left-right pair with the non-slip wheel on the same side A non-slip side torque value setting unit for setting a torque value of one or both of the drive motors;
With
The non-slip side torque value setting unit is
When it is determined whether the first condition set in advance is satisfied and it is determined that the first condition is satisfied, the difference between the added torque value and the updated torque value is calculated from the torque value of the current drive motor. When the subtracted torque value is set and the second condition preset as a condition exclusive of the first condition is satisfied, the added torque value and the update torque are added to the current torque value of the drive motor. A drive control device for a vehicle, wherein a torque value to which a difference from the value is added is set.   The first condition includes that the vehicle speed is equal to or higher than a predetermined vehicle speed, and the second condition includes that the vehicle speed is less than a predetermined vehicle speed. Vehicle drive control device. The non-slip side torque value setting unit is
When the vehicle speed is equal to or higher than the first threshold, it is determined that the first condition is satisfied, and a torque value obtained by subtracting the difference between the added torque value and the updated torque value from the current torque value of the drive motor is obtained. When the vehicle speed is less than the second threshold value, which is lower than the first threshold value, it is determined that the second condition is satisfied, and the torque value of the current drive motor is The vehicle drive control device according to claim 2, wherein a torque value to which a difference from the updated torque value is added is set. The non-slip side torque value setting unit is
4. The vehicle drive control device according to claim 3, wherein when the vehicle speed is less than the first threshold and greater than or equal to the second threshold, a torque value is set according to the vehicle speed. 5.   The first condition includes that the road resistance value is less than a predetermined value, and the second condition includes that the road resistance value is not less than a predetermined value. The drive control device for a vehicle according to any one of claims 1 to 4. A travel mode setting unit that sets at least one travel mode from a plurality of travel modes including a first travel mode and a second travel mode that have at least different torque value setting conditions;
The non-slip side torque value setting unit is
When the travel mode setting unit sets the first travel mode, it is determined that the first condition is satisfied, and when the travel mode setting unit sets the second travel mode, the first travel mode is set. The vehicle drive control device according to claim 1, wherein it is determined that two conditions are satisfied.   The vehicle drive control device according to claim 6, wherein the travel mode setting unit sets a travel mode in accordance with a driver's operation.

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