JP2014193644A - Forward/backward movement determination apparatus of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forward/backward movement determination apparatus of a vehicle capable of determining precisely a forward/backward movement state of the vehicle, even when forward/backward movement information cannot be obtained from a wheel speed sensor.SOLUTION: A control unit 2 estimates a road surface gradient θ, calculates a required torque Tl(θ) which is required at the minimum for moving a vehicle in a direction shown by a shift position to a road surface having the estimated road surface gradient θ, and determines the forward/backward movement state of the vehicle based on a comparison result between a driving torque Tr and the required torque Tl(θ) of an engine and a present shift position, when wheel speed V (absolute value) detected by a wheel speed sensor 7 is changed via zero.

Description

  The present invention relates to a vehicle forward / reverse determination device that can accurately determine the vehicle's forward / backward travel state.

  Generally, in vehicles such as automobiles, various vehicle controls such as start-up control and constant speed running control are performed. In order to realize these vehicle controls with high accuracy, it is important to correct the required torque of the engine based on the road surface gradient.

  Therefore, conventionally, many proposals have been made for techniques for detecting a road surface gradient. For example, Patent Document 1 discloses a gravitational acceleration sensor (longitudinal acceleration sensor) installed in a traveling direction on a vehicle, A wheel speed sensor, continuously reading the pulse time interval of the wheel speed sensor, and calculating the acceleration A ′ with respect to the road surface of the vehicle based on the temporal variation, and synchronizing the longitudinal acceleration sensor A technique is disclosed in which an output value (acceleration A) is read and a road surface gradient is detected based on the relationship between the deviation between both accelerations A and A ′ and the gravitational acceleration.

Japanese Patent No. 2626033

  By the way, in the technique disclosed in Patent Document 1 described above, it is important that the forward / backward traveling state of the vehicle is appropriately determined in order to accurately detect the road surface gradient. Such forward / reverse determination can be realized by using, for example, a polyphase wheel speed sensor capable of detecting the vehicle forward / reverse state together with the wheel speed. This is more expensive than a single-phase wheel speed sensor intended only for speed detection.

  The present invention has been made in view of the above circumstances, and provides a vehicle forward / reverse determination device that can accurately determine the vehicle's forward / backward travel state even when forward / backward travel information cannot be obtained from a wheel speed sensor. With the goal.

  A vehicle forward / reverse determination device according to an aspect of the present invention includes a shift position detection unit that detects a shift position, a drive torque estimation unit that estimates a drive torque generated by a power source, and a road surface gradient estimation unit that estimates a road surface gradient. And a necessary torque calculating means for calculating a minimum required torque for moving the vehicle in the direction indicated by the shift position with respect to the estimated road surface having the road surface gradient, and detecting an absolute value of the rotational speed of the wheel. The vehicle speed detection means, and when the absolute value of the rotational speed of the wheel changes via zero, the vehicle forward-reverse state based on the comparison result between the drive torque and the required torque and the shift position And a forward / reverse determination means for determining.

  According to the vehicle forward / reverse determination device of the present invention, it is possible to accurately determine the vehicle's forward / backward travel state even when the forward / backward information cannot be obtained from the wheel speed sensor.

Functional block diagram showing the road slope estimation device Explanatory drawing which shows the relationship between the sign of road surface inclination (theta), and a gradient state Flowchart showing a forward / reverse determination routine (part 1) Flowchart showing the forward / reverse determination routine (part 2) Flowchart showing a forward / reverse determination routine (No. 3) Flowchart showing a forward / backward determination verification routine Map showing the relationship between estimated slope and required torque Explanatory drawing which shows an example of transition of the 1st, 2nd road surface gradient Transition diagram of the forward / reverse state when the shift position is in the R range Transition diagram of forward / backward movement when the shift position is in the D range Transition diagram of the forward / reverse state when the shift position is in the N range Transition diagram of the forward / reverse state when the shift position is in the P range

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a functional block diagram showing a road surface gradient estimation device, FIG. 2 is an explanatory diagram showing the relationship between the sign of the road surface gradient θ and the gradient state, and FIGS. 6 is a flowchart showing a forward / backward determination verification routine, FIG. 7 is a map showing the relationship between the estimated slope value and the required torque, and FIG. 8 is an example of the transition of the first and second road surface gradients. FIG. 9 is a transition diagram of the forward / reverse state when the shift position is in the R range, FIG. 10 is a transition diagram of the forward / backward state when the shift position is in the D range, and FIG. FIG. 12 is a transition diagram of the forward / reverse state when the shift position is in the P range.

  In FIG. 1, reference numeral 1 denotes a road surface gradient estimation device mounted on a vehicle. In this embodiment, the road surface gradient estimation device 1 has a function as a forward / backward determination device that determines a forward / backward state of the vehicle. The main part of the road surface gradient estimation device is mainly composed of a control unit 2 composed of a microcomputer or the like.

  The control unit 2 is connected to an engine control unit 5 that controls an engine (not shown) that is a power source. The engine control unit 5 has a function as drive torque estimation means. For example, the engine control unit 5 estimates the engine drive torque based on the intake air amount of the engine and the vehicle speed, and outputs it to the control unit 2.

  Further, the control unit 2 includes an inhibitor switch 6 as a shift position detecting means for detecting the shift position selected by the driver, a wheel speed sensor 7 as a wheel speed detecting means for detecting the rotational speed (wheel speed) of the wheel, Various switches and sensors such as a longitudinal acceleration sensor 8 that detects acceleration (longitudinal acceleration) acting in the longitudinal direction of the vehicle body, a brake pedal switch 9 that is turned on when the driver depresses the brake pedal, and the like are connected. Here, in the present embodiment, the inhibitor switch 6 detects, for example, a drive “D” range, a reverse “R” range, a neutral “N” range, a parking “P” range, and the like as shift positions (shift ranges). . The wheel speed sensor 7 is constituted by, for example, a single-phase wheel speed sensor that detects the wheel speed of the front wheel, and the wheel speed V that does not have information on the rotation direction (that is, the absolute value of the wheel rotation speed). To detect.

  Then, the control unit 2 estimates the road surface gradient θ at the current vehicle position based on each of the input signals described above, and determines whether the vehicle is moving forward or backward (forward, backward, or completely stopped). ).

  For this reason, for example, as shown in FIG. 1, the control unit 2 includes a road surface gradient estimation unit 10 as a road surface gradient estimation unit, a required torque calculation unit 11 as a necessary torque calculation unit, and a front / rear determination unit as a forward / backward determination unit. The advance determination unit 12 is included. Further, the control unit 2 includes a filter processing unit 13 as a smoothing unit and a forward / backward determination verification unit 14 as a forward / backward determination verification unit.

  Here, in the present embodiment, as shown in FIG. 2, a case where the road surface gradient θ indicates a “positive” value is defined as a trailing slope, and a case where the road surface gradient θ exhibits a “negative” value is defined as a trailing slope. To explain.

As shown in FIG. 1, the road surface gradient estimation unit 10 receives shift position information from the inhibitor switch 6, receives wheel speed V (absolute value) of the front wheels from the wheel speed sensor 7, and automatically receives from the longitudinal acceleration sensor 8. A longitudinal acceleration A acting on the car is input. Further, the road surface gradient estimation unit 10 is input with the forward / backward travel information of the host vehicle determined by the forward / backward determination unit 12 described later. Then, the road surface gradient estimation unit 10 gives the rotation direction to the wheel speed V based on the forward / reverse information of the host vehicle, calculates the acceleration A ′ based on the change amount of the wheel speed V, and the following (1) The road surface gradient θ is estimated using the equation.

  Here, g in the equation (1) is a gravitational acceleration. Then, the road surface gradient estimation unit 10 determines whether the road surface is “bottom slope” or “bottom slope” based on the estimated value of the road surface gradient θ.

  For example, the road surface gradient θ estimated in this way is subjected to smoothing processing by filter processing in the filter processing unit 13, and then the necessary torque calculation unit 11, the forward / reverse determination unit 12, and the forward / backward determination verification unit 14. And other various control units including the engine control unit 5 (see FIG. 1).

  The required torque calculation unit 11 receives the road surface gradient (gradient estimation value) θ smoothed by the filter processing unit 13. Further, for example, as shown in FIG. 7, the required torque calculation unit 11 includes a vehicle in a direction indicated by a gradient estimated value θ and a shift position (“R” and “D”) on the road surface having the gradient estimated value θ. The relationship with the minimum required torque Tl (θ) required for moving (running) the vehicle is obtained in advance through experiments, simulations, etc., and stored in a map. Then, the necessary torque calculation unit 11 calculates the necessary torque Tl (θ) based on θ by estimating the gradient with reference to the map.

  The forward / reverse determination unit 12 receives engine drive torque Tr from the engine control unit 5, shift position information from the inhibitor switch 6, and wheel speed V (absolute value) of the front wheels from the wheel speed sensor 7. The longitudinal acceleration A acting on the vehicle is inputted from the longitudinal acceleration sensor 8, and the brake pedal depression information by the driver is inputted from the brake pedal switch 9. Further, the forward / backward determination unit 12 receives the road surface gradient θ smoothed by the filter processing unit 13 and the necessary torque Tl (θ) calculated by the necessary torque calculation unit 11.

  The forward / reverse determination unit 12 cumulatively performs forward / reverse determination using the previous determination result. Basically, when the shift position is at the travel position (“D” or “R”), the wheel When the speed V (absolute value) changes via zero (experience), the forward / reverse state of the vehicle is determined based on the comparison result between the drive torque Tr and the required torque Tl (θ) and the current shift position. judge. However, when the shift position is “N”, the forward / reverse determination unit 12 determines the forward / reverse state based on the wheel speed V and the road surface gradient θ. Further, the forward / reverse determination unit 12 determines the complete stop state of the own vehicle when the wheel speed V is zero and the brake pedal is depressed. When the shift position is “P”, the forward / reverse determination unit 12 determines a complete stop state.

  The forward / backward determination result (including the complete stop state) determined in this way is output to the road surface gradient estimation unit 10 and the forward / backward determination verification unit 14, and various other types including the engine control unit 5. It is output to the control unit or the like (see FIG. 2).

  The forward / reverse determination verification unit 14 receives shift position information from the inhibitor switch 6, and receives the wheel speed V (absolute value) of the front wheels from the wheel speed sensor 7, and the longitudinal acceleration acting on the vehicle from the longitudinal acceleration sensor 8. A is entered. The forward / backward determination verification unit 14 receives the forward / backward determination result determined by the forward / backward determination unit 12.

Based on the wheel speed V, the forward / reverse determination determination unit 14 determines whether the vehicle is traveling at a constant speed or performing acceleration / deceleration traveling. When the acceleration / deceleration traveling is determined after determining the constant speed travel, the forward / reverse determination determination unit 14 determines whether the constant speed travel is determined again, based on the longitudinal acceleration A, the wheel speed V, and the forward / backward determination result. The road gradient [theta] (first road gradient [theta] 1) is estimated using the above equation (1). Further, the forward / backward determination verification unit 14 estimates the road surface gradient θ (second road surface gradient θ2) using the following equation (2) based on the same parameters.

  Here, it is assumed that the second road surface gradient θ2 obtained by the equation (2) is an error (reverse) in the forward / reverse determination result determined by the forward / reverse determination unit 12, as is apparent from the equation. It is the road surface gradient estimated in the case.

  Further, the forward / backward determination verification unit 14 calculates road surface gradient reference values θa1 and θa1 based on the longitudinal acceleration A at each constant speed determined before and after acceleration / deceleration driving, for example, these road surface gradient references A history of the road surface gradient reference value θa during acceleration / deceleration traveling is estimated by linearly connecting the values θa1 and θa1. When the error in the history of the first road surface gradient θ1 is larger than the error in the history of the second road surface gradient θ2 with respect to the history of the road surface gradient reference value θa, the current forward / reverse determination unit 12 determines. It is determined that the forward / reverse state is incorrect. When it is determined that the forward / reverse state is an erroneous determination in this way, the forward / backward determination verification unit 14 instructs the forward / reverse determination unit 12 to correct the determination result of the forward / reverse state.

  Next, the forward / reverse determination performed by the forward / reverse determination unit 12 will be described with reference to the flowchart of the forward / reverse determination routine shown in FIGS.

  This routine is repeatedly executed every set time. When the routine starts, the forward / reverse determination unit 12 first calculates the estimated road surface gradient value θ estimated by the road surface gradient estimation unit 10 in step S101. Read.

  In subsequent step S102, the forward / reverse determination unit 12 determines the currently selected shift position based on an input signal from the inhibitor switch 6, for example.

  The forward / reverse determination unit 12 proceeds to step S103 when it is determined that the shift position is reverse “R” as a result of determination in step S102, and when it is determined that the shift position is drive “D”. Proceeds to step S113, and if it is determined that the shift position is neutral “N”, the process proceeds to step S123. If it is determined in step S102 that the shift position is parking “P”, the forward / reverse determination unit 12 proceeds to step S112 and determines that the current vehicle state is in a complete stop state. , Exit the routine.

  When proceeding from step S102 to step S103, the forward / reverse determination unit 12 checks the previous determination state (forward state, reverse state, or complete stop state).

  The forward / reverse determination unit 12 proceeds to step S104 when determining that the previous determination state is the complete stop state, and proceeds to step S106 when determining that the previous determination state is the forward state. If it is determined that the previous state is the reverse state, the process proceeds to step S108.

  When the process proceeds from step S103 to step S104, the forward / reverse determination unit 12 turns the wheel speed V (absolute value) to a value greater than zero (that is, the wheel speed V changes via zero). ) And whether or not the drive torque Tr is less than the necessary torque Tl (θ).

  If it is determined in step S104 that the wheel speed V (absolute value) has turned to a value greater than zero and the drive torque Tr is less than the required torque Tl (θ), the forward / reverse determination unit 12 Then, the process proceeds to step S110, and after determining that the current vehicle is in a forward state (that is, changed from a complete stop state to a forward state), the routine is exited.

  On the other hand, when it is determined in step S104 that the wheel speed V (absolute value) is still zero, or when it is determined that the drive torque Tr is equal to or greater than the necessary torque Tl (θ), the forward / reverse determination unit 12 In step S105, it is checked whether or not the wheel speed V (absolute value) has turned to a value greater than zero and the drive torque Tr is equal to or greater than the required torque Tl (θ).

  If it is determined in step S105 that the wheel speed V (absolute value) has turned to a value greater than zero and the drive torque Tr is equal to or greater than the required torque Tl (θ), the forward / reverse determination unit 12 Then, the process proceeds to step S111, and after determining that the current vehicle is in the reverse drive state (that is, changed from the complete stop state to the reverse drive state), the routine is exited.

  On the other hand, when it is determined in step S105 that the wheel speed V (absolute value) is still zero, or when it is determined that the drive torque Tr is less than the necessary torque Tl (θ), the forward / reverse determination unit 12 The routine is exited while maintaining the current judgment state (that is, the complete stop state).

  Further, when proceeding from step S103 to step S106, the forward / reverse determination unit 12 indicates that the wheel speed V (absolute value) is zero, or the wheel speed V (absolute value) is a preset threshold value (for example, several km / h) or less is changed to a downward convex shape with the minimum value, and it is checked whether the drive torque Tr is equal to or greater than the required torque Tl (θ). Here, in the scene where the process proceeds to step S106, the forward / reverse state of the host vehicle and the shift position do not match (that is, the host vehicle is in the forward state even though the shift position is “R” indicating reverse travel). In addition to the scene where the vehicle is on an uphill road, for example, the shift position is changed from “D” to “R” without stopping completely while the vehicle is moving forward. A scene immediately after being switched to "is assumed. In such a scene, for example, it is assumed that the wheel rotation direction is reversed without the wheel speed V (absolute value) passing through zero due to wheel spin or the like. Therefore, in order to deal with such a situation, in step S106, a downward convex change in the wheel speed V (absolute value) is also added as a determination requirement in order to relax the condition for determination of reverse travel.

  In step S106, when it is determined that the wheel speed V (absolute value) is zero and the drive torque Tr is equal to or greater than the necessary torque Tl (θ), or the wheel speed V (absolute value) is When it is determined that the value is not more than a preset threshold value, and the driving torque Tr is equal to or greater than the required torque Tl (θ), the forward / reverse determination unit 12 determines whether the forward / reverse determination unit 12 is step S111. And the routine exits the routine after determining that the current vehicle is in the reverse state (ie, the vehicle has changed from the forward state to the reverse state).

  On the other hand, in step S106, the wheel speed V (absolute value) is not zero, and the wheel speed V (absolute value) changes to a downward convex shape having a value equal to or lower than a preset threshold value as a minimum value. If it is determined that the drive torque Tr is less than the required torque Tl (θ), the forward / reverse determination unit 12 proceeds to step S107, the wheel speed V is zero, and the driver determines Check whether the brake pedal is depressed for a certain period of time.

  If it is determined in step S107 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S112. After determining that the current vehicle is in a stopped state (that is, from a forward state to a complete stop state), the routine exits.

  On the other hand, when the wheel speed V is zero and the state where the brake pedal is being depressed by the driver does not continue for a certain time in step S107, the forward / reverse determination unit 12 determines that the current determination state (i.e., forward The routine is exited while maintaining the state.

  When the process proceeds from step S103 to step S108, the forward / reverse determination unit 12 determines whether the wheel speed V (absolute value) is zero and the drive torque Tr is less than the required torque Tl (θ). Check out.

  If it is determined in step S108 that the wheel speed (absolute value) is zero and the drive torque Tr is less than the required torque Tl (θ), the forward / reverse determination unit 12 proceeds to step S110. The vehicle exits the routine after determining that the current vehicle is in a forward state (that is, has changed from a reverse state to a forward state).

  On the other hand, when it is determined in step S108 that the wheel speed (absolute value) is not zero, or when it is determined that the drive torque Tr is equal to or greater than the necessary torque Tl (θ), the forward / reverse determination unit 12 In step S109, it is checked whether or not the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time.

  If it is determined in step S109 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S112. After it is determined that the current vehicle is in a stopped state (that is, the vehicle has changed from a reverse state to a complete stop state), the routine is exited.

  On the other hand, when it is determined in step S109 that the wheel speed V is zero and the state in which the driver depresses the brake pedal does not continue for a certain period of time, the forward / reverse determination unit 12 determines whether the current determination state ( That is, the routine exits while maintaining the reverse state.

  As shown in FIG. 4, when the process proceeds from step S102 to step S113, the forward / reverse determination unit 12 checks the previous determination state (the forward state, the reverse state, or the complete stop state).

  The forward / reverse determination unit 12 proceeds to step S114 when it is determined that the previous determination state is a complete stop state, and proceeds to step S116 when it is determined that the previous determination state is a forward state. If it is determined that the previous state is the reverse state, the process proceeds to step S118.

  When the process proceeds from step S113 to step S114, the forward / reverse determination unit 12 turns the wheel speed V (absolute value) to a value greater than zero (that is, the wheel speed V changes via zero). ) And whether or not the drive torque Tr is equal to or greater than the required torque Tl (θ).

  When it is determined in step S114 that the wheel speed V (absolute value) has turned to a value greater than zero and the drive torque Tr is equal to or greater than the required torque Tl (θ), the forward / reverse determination unit 12 Then, the process proceeds to step S120, and after determining that the current vehicle is in a forward state (that is, changed from a complete stop state to a forward state), the routine exits.

  On the other hand, when it is determined in step S114 that the wheel speed V (absolute value) is still zero, or when it is determined that the drive torque Tr is less than the necessary torque Tl (θ), the forward / reverse determination unit 12 In step S115, it is checked whether or not the wheel speed V (absolute value) has turned to a value larger than zero and the drive torque Tr is less than the required torque Tl (θ).

  If it is determined in step S115 that the wheel speed V (absolute value) has turned to a value greater than zero and the drive torque Tr is less than the required torque Tl (θ), the forward / reverse determination unit 12 Then, the process proceeds to step S121, and after determining that the current vehicle is in the reverse drive state (that is, the vehicle has changed from the complete stop state to the reverse drive state), the routine exits.

  On the other hand, when it is determined in step S115 that the wheel speed V (absolute value) is still zero, or when it is determined that the drive torque Tr is equal to or greater than the necessary torque Tl (θ), the forward / reverse determination unit 12 The routine is exited while maintaining the current judgment state (that is, the complete stop state).

  Further, when proceeding from step S113 to step S116, the forward / reverse determination unit 12 determines whether or not the wheel speed V (absolute value) is zero and the drive torque Tr is less than the required torque Tl (θ). Check out.

  If it is determined in step S116 that the wheel speed (absolute value) is zero and the drive torque Tr is less than the necessary torque Tl (θ), the forward / reverse determination unit 12 proceeds to step S121. After determining that the current vehicle is in the reverse drive state (that is, the vehicle has changed from the forward drive state to the reverse drive state), the routine exits.

  On the other hand, when it is determined in step S116 that the wheel speed (absolute value) is not zero, or when it is determined that the drive torque Tr is equal to or greater than the necessary torque Tl (θ), the forward / reverse determination unit 12 In step S117, it is checked whether or not the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time.

  If it is determined in step S117 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S122. After determining that the current vehicle is in a stopped state (that is, from a forward state to a complete stop state), the routine exits.

  On the other hand, when it is determined in step S117 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver does not continue for a certain period of time, the forward / reverse determination unit 12 determines whether the current determination state ( That is, the routine is exited while the forward movement state is maintained.

  Further, when the process proceeds from step S113 to step S118, the forward / reverse determination unit 12 indicates that the wheel speed V (absolute value) is zero, or the wheel speed V (absolute value) is a preset threshold value (for example, several km / h) or less is changed to a downward convex shape with the minimum value, and it is checked whether the drive torque Tr is equal to or greater than the required torque Tl (θ). Here, in the scene that proceeds to step S118, the forward / reverse state of the host vehicle and the shift position do not match (that is, the host vehicle is in the reverse state although the shift position is “D” instructing forward movement). In addition to the scene where the vehicle is on an uphill road, for example, the shift position can be changed from “R” to “D” without stopping completely while the vehicle is moving backward. A scene immediately after being switched to "is assumed. In such a scene, for example, it is assumed that the wheel rotation direction is reversed without the wheel speed V (absolute value) passing through zero due to wheel spin or the like. Therefore, in order to deal with such a situation, in step S118, a downward convex change in the wheel speed V (absolute value) is also added as a determination requirement in order to relax the conditions for determination of forward travel.

  In step S118, when it is determined that the wheel speed V is zero and the driving torque Tr is equal to or higher than the necessary torque Tl (θ), or the wheel speed V (absolute value) is set in advance. When it is determined that the value is equal to or lower than the threshold and the driving torque Tr is equal to or greater than the necessary torque Tl (θ), the forward / reverse determination unit 12 proceeds to step S120. After determining that the current vehicle is in the forward state (that is, changed from the reverse state to the forward state), the routine exits.

  On the other hand, in step S118, the wheel speed V (absolute value) is not zero, and the wheel speed V (absolute value) changes to a downward convex shape having a value equal to or lower than a preset threshold value as a minimum value. If it is determined that the drive torque Tr is less than the required torque Tl (θ), the forward / reverse determination unit 12 proceeds to step S119, the wheel speed V is zero, and the driver determines Check whether the brake pedal is depressed for a certain period of time.

  If it is determined in step S119 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S122. After it is determined that the current vehicle is in a stopped state (that is, the vehicle has changed from a reverse state to a complete stop state), the routine is exited.

  On the other hand, when it is determined in step S119 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver does not continue for a certain period of time, the forward / reverse determination unit 12 determines the current determination state ( That is, the routine exits while maintaining the reverse state.

  As shown in FIG. 5, when the process proceeds from step S102 to step S123, the forward / reverse determination unit 12 checks the previous determination state (the forward state, the reverse state, or the complete stop state).

  The forward / reverse determination unit 12 proceeds to step S124 when determining that the previous determination state is a complete stop state, and proceeds to step S126 when determining that the previous determination state is a forward state. If it is determined that the previous state is the reverse state, the process proceeds to step S128.

  When the process proceeds from step S123 to step S124, the forward / reverse determination unit 12 turns the wheel speed V (absolute value) to a value greater than zero (that is, the wheel speed V changes via zero). In addition, it is examined whether or not the road surface gradient θ estimated by the road surface gradient estimation unit 10 indicates a rising slope.

  If it is determined in step S124 that the wheel speed V (absolute value) has turned to a value greater than zero and the road surface gradient θ indicates an uphill gradient, the forward / reverse determination unit 12 performs step Proceeding to S130, after determining that the current vehicle is in the forward traveling state (that is, changing from the complete stop state to the forward traveling state), the routine exits.

  On the other hand, when it is determined in step S124 that the wheel speed V (absolute value) is still zero, or when it is determined that the road surface gradient θ does not indicate a rising slope, the forward / reverse determination unit 12 determines whether the wheel speed V (absolute value) does not indicate a rising slope. Then, it is checked whether or not the wheel speed V (absolute value) has turned to a value greater than zero and the road surface gradient θ indicates a trailing slope.

  When it is determined in step S125 that the wheel speed V (absolute value) has turned to a value greater than zero and the road surface gradient θ indicates a trailing slope, the forward / reverse determination unit 12 Proceeding to S131, after determining that the current vehicle is in the reverse drive state (that is, from the complete stop state to the reverse drive state), the routine exits.

  On the other hand, when it is determined in step S125 that the wheel speed V (absolute value) is still zero, or when it is determined that the road surface gradient θ does not indicate the trailing slope, the forward / reverse determination unit 12 The routine is exited while the determination state (that is, the complete stop state) is maintained.

  Further, when the process proceeds from step S123 to step S126, the forward / reverse determination unit 12 checks whether or not the wheel speed V (absolute value) is zero and the road surface gradient θ indicates a trailing slope.

  In step S126, when it is determined that the wheel speed (absolute value) is zero and the road surface gradient θ indicates a downhill gradient, the forward / reverse determination unit 12 proceeds to step S131, The vehicle exits the routine after determining that the vehicle is in the reverse drive state (that is, has changed from the forward drive state to the reverse drive state).

  On the other hand, when it is determined in step S126 that the wheel speed (absolute value) is not zero, or when it is determined that the road surface gradient θ does not indicate the trailing slope, the forward / reverse determination unit 12 performs step S127. Then, it is checked whether or not the wheel speed V is zero and the state where the driver is stepping on the brake pedal continues for a certain period of time.

  In step S127, when it is determined that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S132, After determining that the current vehicle is in a stopped state (that is, from a forward state to a complete stop state), the routine exits.

  On the other hand, when it is determined in step S127 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver does not continue for a certain period of time, the forward / reverse determination unit 12 determines the current determination state ( That is, the routine is exited while the forward movement state is maintained.

  Further, when proceeding from step S123 to step S128, the forward / reverse determination unit 12 checks whether or not the wheel speed V (absolute value) is zero and the road surface gradient θ indicates an uphill gradient.

  In Step S128, when it is determined that the wheel speed V (absolute value) is zero and the road surface gradient θ indicates a rising slope, the forward / reverse determination unit 12 proceeds to Step S130. After determining that the current vehicle is in the forward state (that is, changed from the reverse state to the forward state), the routine exits.

  On the other hand, when it is determined in step S128 that the wheel speed V (absolute value) is not zero, or when it is determined that the road surface gradient θ does not indicate a rising gradient, the forward / reverse determination unit 12 performs step Proceeding to S129, it is checked whether or not the state where the wheel speed V is zero and the brake pedal is being depressed by the driver continues for a certain period of time.

  If it is determined in step S129 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver continues for a certain period of time, the forward / reverse determination unit 12 proceeds to step S132, After it is determined that the current vehicle is in a stopped state (that is, the vehicle has changed from a reverse state to a complete stop state), the routine is exited.

  On the other hand, when it is determined in step S129 that the wheel speed V is zero and the state where the brake pedal is being depressed by the driver does not continue for a certain period of time, the forward / reverse determination unit 12 determines the current determination state ( That is, the routine exits while maintaining the reverse state.

  By such control, for example, as shown in FIGS. 9 to 12, the determination result of the forward / rearward state changes at each shift position.

  Next, verification performed in the forward / reverse determination verification unit 14 for the forward / reverse determination result in the forward / reverse determination unit 12 will be described according to the flowchart of the forward / backward determination verification routine shown in FIG.

  This routine is repeatedly executed every set time. When the routine starts, the forward / reverse determination determination unit 14 first checks in step S201 whether or not it is immediately after the forward / backward determination is switched. .

  If it is determined in step S201 that it is immediately after the forward / backward determination is switched, the forward / backward determination verification unit 14 proceeds to step S202, and records the first and second gradient estimated values θ1 and θ2 described later. After clearing, the process proceeds to step S203.

  On the other hand, if it is determined in step S201 that it is not immediately after the forward / backward determination is switched, the forward / backward determination verification unit 14 proceeds to step S203 as it is.

  When the process proceeds from step S201 or step S202 to step S203, the forward / reverse determination verification unit 14 checks whether the current determination result of the forward / reverse state is a forward state or a reverse state.

  If it is determined in step S203 that the current forward / backward state determination result is not the forward state or the reverse state, that is, if the current forward / backward state determination result is determined to be a complete stop state, the forward / backward determination is performed. The verification unit 14 exits the routine as it is.

  On the other hand, when it is determined in step S203 that the determination result of the current forward / reverse state is the forward state or the reverse state, the forward / backward determination verification unit 14 proceeds to step S204, and the first and second road surface gradients θ1, θ2 is estimated, and these estimation results are stored as a gradient estimated value history.

  In other words, the forward / reverse determination verification unit 14 gives the rotational direction to the wheel speed V (absolute value) based on the current forward / backward determination result and the shift position, and changes the wheel speed V to which the rotational direction is applied. Based on the acceleration A ′ and the longitudinal acceleration A, the road gradient θ (first road gradient θ1) is calculated using the above-described equation (1). Further, the forward / backward determination verification unit 14 estimates the road surface gradient θ (second road surface gradient θ2) using the above-described equation (2) based on the acceleration A ′ and the post-backward acceleration A. Then, the forward / backward determination verification unit 14 stores the estimated first and second road surface gradients θ1 and θ2 as histories (see FIG. 8).

  When the process proceeds from step S204 to step S205, the forward / reverse determination determination unit 14 checks whether or not the current host vehicle is traveling at a constant speed based on the acceleration A '.

  If it is determined in step S205 that the current host vehicle is not traveling at a constant speed, the forward / reverse determination determination unit 14 directly exits the routine.

  On the other hand, if it is determined in step S205 that the current host vehicle is traveling at a constant speed, the forward / reverse determination determination unit 14 proceeds to step S206, estimates the history of the road surface gradient reference value θa, and this road surface gradient reference An error between the value θa and each history of the first and second road surface gradients θ1 and θ2 is calculated.

  That is, considering that the road surface gradient can be accurately calculated from the longitudinal acceleration value when the vehicle is traveling at a constant speed, the forward / reverse determination determination unit 14 determines whether the road surface is based on the longitudinal acceleration A at the time of determining the previous constant speed travel. The slope reference value θa1 is calculated, and the road surface slope reference value θa2 is calculated based on the longitudinal acceleration A in the current constant speed travel. For example, in the example shown in FIG. 8, when the constant speed travel is determined at the timing T1, the forward / reverse determination verification unit 14 determines the road surface gradient from the value of the longitudinal acceleration A at the timing T0 at which the immediately preceding constant speed travel is determined. The reference value θa1 is calculated, and the road surface gradient reference value θa2 is calculated from the value of the longitudinal acceleration A at the current timing T1. Further, for example, the history of the road surface gradient reference value θa from the timing T0 to the timing T1 is estimated by linearly connecting the road surface gradient reference values θa1 and θa2. Then, the forward / backward determination verification unit 14 calculates an error (for example, least square error) between the history of the road surface gradient reference value θa and the history of the first and second road surface gradients θ1 and θ2.

  When the process proceeds from step S206 to step S207, the forward / backward determination verification unit 14 determines that the error between the road surface gradient reference value θa and the first road surface gradient θ1 is greater than the error between the road surface gradient reference value θa and the second road surface gradient θ2. Check if it is too big.

  If it is determined in step S207 that the error between the road surface gradient reference value θa and the second road surface gradient θ2 is large, the forward / reverse determination determination unit 14 proceeds directly to step S209.

  On the other hand, when it is determined in step S207 that the error between the road gradient reference value θa and the first road gradient θ1 is large, the forward / reverse determination determination unit 14 proceeds to step S208 and is determined by the current forward / reverse determination unit 12. It is determined that the current forward state or the reverse state is incorrect, and the forward / backward determination unit 12 is instructed to change to a determination state opposite to the current determination, and then the process proceeds to step S209.

  Then, when the process proceeds from step 207 or step S208 to step S209, the forward / backward determination verification unit 14 clears the history of the first and second gradient estimated values θ1 and θ2, and then exits the routine.

  According to such an embodiment, the minimum necessary torque Tl (θ) required for estimating the road surface gradient θ and moving the vehicle in the direction indicated by the shift position with respect to the road surface having the estimated road surface gradient θ. When the wheel speed V (absolute value) detected by the wheel speed sensor 7 changes via zero, the comparison result between the engine driving torque Tr and the required torque Tl (θ) and the current shift position By determining the forward / reverse state of the vehicle based on the above, the forward / backward state of the vehicle can be accurately determined even when the forward / backward information from the wheel speed sensor 7 cannot be obtained. Therefore, an inexpensive and simple single-phase wheel speed sensor can be effectively applied.

  In this case, if acceleration / deceleration traveling is determined after determining constant speed travel based on the wheel speed V, the longitudinal acceleration A, the wheel speed V, and the forward / backward determination result until the constant speed travel is determined again. Based on the equation (1), the road surface gradient θ (first road surface gradient θ1) is estimated. Further, using the equation (2), the road surface gradient θ ( The second road surface gradient θ2) is estimated, and the road surface gradient reference values θa1 and θa1 are calculated based on the longitudinal acceleration A at the time of each constant speed travel determined before and after the acceleration / deceleration travel, respectively. When the history of the road surface gradient reference value θa is estimated, and the history error of the first road surface gradient θ1 is larger than the history error of the second road surface gradient θ2 with respect to the history of the road surface gradient reference value θa The forward / reverse movement currently determined by the forward / reverse determination unit 12 Therefore, even if there is an erroneous determination in the forward / reverse determination made based on the comparison result between the drive torque Tr and the required torque Tl (θ), the erroneous determination is corrected accurately. can do.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention.

  For example, in the above-described embodiment, an example in which the present invention is applied to a vehicle including a single-phase wheel speed sensor has been described. However, the present invention is not limited to this, for example, a multiphase The present invention can also be applied to a vehicle equipped with a wheel speed sensor of the type. In this case, for example, even when a part of the electromagnetic pickup or the like of the wheel speed sensor breaks down, it is possible to accurately determine the forward / backward traveling state.

1 ... Road surface gradient estimation device (back and forth determination device)
2 ... Control unit 5 ... Engine control unit (drive torque estimating means)
6 ... Inhibitor switch (shift position detection means)
7: Wheel speed sensor (wheel speed detection means)
8 ... Longitudinal acceleration sensor (longitudinal acceleration detection means)
9: Brake pedal switch 10: Road surface gradient estimation unit (road surface gradient estimation means)
11: Necessary torque calculation unit (necessary torque calculation means)
12 ... Forward / reverse determination unit (forward / reverse determination unit)
13: Filter processing unit (smoothing processing means)
14 ... Forward / backward determination verification unit (forward / backward determination verification means)

Claims (5)

Shift position detecting means for detecting the shift position;
Drive torque estimating means for estimating the drive torque generated in the power source;
Road surface gradient estimating means for estimating the road surface gradient;
Necessary torque calculating means for calculating a minimum required torque for moving the vehicle in the direction indicated by the shift position with respect to the estimated road surface having the road surface gradient;
Wheel speed detection means for detecting the absolute value of the rotational speed of the wheel;
When the absolute value of the rotational speed of the wheel changes via zero, a forward / reverse determination means for determining a forward / reverse state of the vehicle based on a comparison result between the drive torque and the required torque and the shift position And a vehicle forward / reverse determination device.   Even if the absolute value of the rotational speed of the wheel does not change via zero, the forward / reverse determination means does not match the previously determined forward / reverse state and the shift position, and the wheel When the absolute value of the rotational speed of the vehicle changes to a downward convex shape having a value equal to or less than a preset threshold as a minimum value, the vehicle front and rear are compared based on the comparison result between the drive torque and the required torque and the shift position. The vehicle forward / reverse determination device according to claim 1, wherein the vehicle advance state is determined.   The longitudinal acceleration acting in the longitudinal direction of the vehicle body and the rotational speed of the wheel until the acceleration / deceleration traveling is determined and the constant speed traveling is determined again after determining the constant speed traveling of the vehicle based on the rotational speed of the wheel. A first road surface gradient is estimated based on the amount of change in the vehicle and the forward / reverse state being currently determined, the amount of change in the longitudinal acceleration, the rotational speed of the wheel, and the forward / backward state currently being determined. The second road surface gradient is estimated on the basis of the opposite state, and the history of the road surface gradient reference value is estimated from the two longitudinal accelerations during the two constant speed travels. When the error in the road gradient history of 1 is larger than the error in the history of the second road gradient, the forward / backward determination verification means for determining that the forward / reverse state currently determined by the forward / reverse determination unit is an error. The claim comprising: Or reverse determination unit before the vehicle according to claim 2.   The road surface gradient estimation means estimates the road surface gradient based on a longitudinal acceleration acting in a longitudinal direction of a vehicle body, a change amount of a rotational speed of the wheel, and the forward / backward moving state currently being determined. The vehicle forward / reverse determination device according to any one of claims 1 to 3.   The vehicle forward / reverse determination device according to any one of claims 1 to 4, further comprising a smoothing processing unit that smoothes the road surface gradient estimated by the road surface gradient estimation unit.

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