Vehicle control device, vehicle control program, and vehicle control method
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- DENSO CORP
- Filing Date
- 2026-01-08
- Publication Date
- 2026-07-30
Smart Images
Figure JP2026000399_30072026_PF_FP_ABST
Abstract
Description
Vehicle control device, vehicle control program, and vehicle control method Cross-reference to related applications
[0001] This application is based on Japanese Application No. 2025-011273 filed on January 27, 2025, the contents of which are incorporated herein by reference.
[0002] The present disclosure relates to a vehicle control device, a vehicle control program, and a vehicle control method for controlling a four-wheel drive vehicle.
[0003] For example, a travel control unit that inputs an accelerator opening signal and a vehicle speed signal and calculates the magnitude of a target torque Tt generated by a drive source using these signals, and a travel control monitoring unit that inputs an accelerator opening signal and a vehicle speed signal and calculates the magnitude of a target torque Ttw generated by a drive source using these signals, and the travel control monitoring unit compares the magnitude of the target torque Ttw with the magnitude of the target torque Tt, and when there is a difference exceeding a predetermined range, transmits a signal indicating a failure. There is a vehicle control device (see Patent Document 1).
[0004] Japanese Unexamined Patent Application Publication No. 2020-18062
[0005] By the way, in a four-wheel drive vehicle, the vehicle is driven by the front-wheel driving force and the rear-wheel driving force. According to the same concept as the vehicle control device described in Patent Document 1, it is necessary to redundantly calculate and monitor the magnitude of the first target torque generated by the drive source of the front wheels, and redundantly calculate and monitor the magnitude of the second target torque generated by the drive source of the rear wheels. In this case, since many new configurations are required, it is not desirable in terms of cost.
[0006] Therefore, it is conceivable to monitor the total target torque, which is the sum of the first target torque and the second target torque. However, when monitoring the total target torque, it is not possible to detect a failure (hereinafter referred to as "reverse-sign torque failure") in which the signs of the first target torque and the second target torque are reversed although the total target torque is within the normal range. When a reverse-sign torque failure occurs, the behavior of the vehicle may become unstable.
[0007] This disclosure was made to solve the above-mentioned problems, and its primary purpose is to suppress the instability of vehicle behavior when a reverse torque fault occurs in a vehicle control device, vehicle control program, and vehicle control method for controlling a four-wheel drive vehicle, without requiring many new configurations.
[0008] A first disclosure for solving the above problems is a vehicle control device for controlling a four-wheel drive vehicle comprising front wheels, a first drive source that generates a driving force to drive the front wheels, rear wheels, and a second drive source that generates a driving force to drive the rear wheels, the control device comprising: a first required torque calculation unit that calculates a first required torque to be required of the first drive source; a second required torque calculation unit that calculates a second required torque to be required of the second drive source; and a reverse sign adjustment unit that, when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are opposite, adjusts the value of at least one of the first required torque and the second required torque to a value closer to zero than before adjustment.
[0009] According to the above configuration, the front wheels are driven by the driving force generated by the first drive source, and the rear wheels are driven by the driving force generated by the second drive source, resulting in a four-wheel drive vehicle. The vehicle is controlled by a vehicle control device.
[0010] Here, the first required torque calculation unit calculates the first required torque to be supplied to the first drive source. Therefore, the driving force that the first drive source uses to drive the front wheels can be controlled by the first required torque calculated by the first required torque calculation unit. In addition, the second required torque calculation unit calculates the second required torque to be supplied to the second drive source. Therefore, the driving force that the second drive source uses to drive the rear wheels can be controlled by the second required torque calculated by the second required torque calculation unit.
[0011] Incidentally, while the total required torque, which is the sum of the first required torque and the second required torque, is within the normal range, there is a risk of a reverse-sign torque failure occurring, where the signs of the first required torque and the second required torque are reversed. In this regard, the reverse-sign adjustment unit adjusts the value of at least one of the first and second required torques to a value closer to zero than before adjustment when the signs of the first and second required torques are reversed. Therefore, when the signs of the first and second required torques are reversed, the difference between the first and second required torques can be reduced. Consequently, even if a reverse-sign torque failure occurs, it is possible to suppress instability in the vehicle's behavior. Furthermore, since there is no need to redundantly calculate and monitor the magnitude of the first required torque and the magnitude of the second required torque, many new configurations are not required.
[0012] The second disclosure is a vehicle control program for controlling a four-wheel drive vehicle comprising front wheels, a first drive source that generates a driving force to drive the front wheels, rear wheels, and a second drive source that generates a driving force to drive the rear wheels, wherein the program causes a computer to perform the following: a process of calculating a first required torque to be requested from the first drive source; a process of calculating a second required torque to be requested from the second drive source; and a process of adjusting the value of at least one of the calculated first required torque and the calculated second required torque to a value closer to zero than before adjustment if the signs of the calculated first required torque and the signs of the calculated second required torque are opposite.
[0013] According to the above configuration, the vehicle control program can achieve the same effects as those described in the first disclosure.
[0014] The above-mentioned and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is a block diagram showing the configuration of a four-wheel drive vehicle equipped with an EVC; Figure 2 is a time chart showing the changes in each required torque when a reverse-sign torque failure occurs in a comparative example; Figure 3 is a block diagram showing the configuration of the EVC and its surroundings; Figure 4 is a flowchart showing the procedures for detecting a reverse-sign torque anomaly, detecting a total torque anomaly, and each F / S; Figure 5 is a diagram showing the manner of anomaly detection and torque adjustment; Figure 6 is a time chart showing the changes in each required torque when a reverse-sign torque failure occurs; and Figure 7 is a block diagram showing the configuration of a four-wheel drive vehicle equipped with an HVC.
[0015] The following describes one embodiment of a vehicle control device for controlling a four-wheel drive electric vehicle, with reference to the drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.
[0016] As shown in Figure 1, the vehicle 2 is equipped with an EVC (Electric Vehicle Controller) 10, an EPS (Electric Power Steering) 20, a brake ECU (Electric Control Unit) 22, a front inverter 24A, a rear inverter 24B, a front motor generator 26A, a rear motor generator 26B, a steering wheel 30, an accelerator pedal 32, a brake pedal 34, an EPS actuator 40, a differential gear 42A, a differential gear 42B, a right front brake 44FR, a left front brake 44FL, a right rear brake 44RR, a left rear brake 44RL, a right front wheel 46FR, a left front wheel 46FL, a right rear wheel 46RR, a left rear wheel 46RL, a battery 50, and an SMR (System Main Relay) 51, etc.
[0017] The right front wheel 46FR and the left front wheel 46FL are steering wheels that determine the direction of travel of vehicle 2. The right front wheel 46FR and the left front wheel 46FL are also drive wheels to which the main required torque is transmitted. The right front wheel 46FR is located on the right front of vehicle 2. The left front wheel 46FL is located on the left front of vehicle 2. "Front" refers to the direction of travel of vehicle 2, which is the upward direction in Figure 1.
[0018] The right front brake 44FR is located on the right front wheel 46FR. The right front brake 44FR operates based on a braking signal input from the brake ECU 22 and applies braking force to the right front wheel 46FR. The left front brake 44FL is located on the left front wheel 46FL. The left front brake 44FL operates based on a braking signal input from the brake ECU 22 and applies braking force to the left front wheel 46FL.
[0019] The right front wheel 46FR and the left front wheel 46FL are configured to change angle to the left and right in sync. The right front wheel 46FR and the left front wheel 46FL are steered by the EPS actuator 40. The EPS actuator 40 is configured to perform steering operations based on the steering signal output from the EPS 20. The EPS 20 receives a steering angle signal. The steering angle signal is a signal output by operating the steering wheel 30. The steering angle signal is a signal that specifies the steering angle intended by the driver.
[0020] Control signals are input to the EPS20 from the EVC10. Brake signals are input to the EPS20 from the brake ECU. The EPS20 calculates a steering signal by performing appropriate calculations based on the steering angle signal, control signal, and brake signal, and inputs it to the EPS actuator 40. The EPS20 inputs the steering signal to the EVC10 and the brake ECU22. The EPS20 is a control device for outputting the steering signal to the EPS actuator 40. The EPS20 is a computer having components such as an interface for sending and receiving signals, a memory for storing information, and a CPU for performing calculations.
[0021] The right rear wheel 46RR and the left rear wheel 46RL are drive wheels to which a secondary required torque smaller than the primary required torque is transmitted. The right rear wheel 46RR is located at the right rear of the vehicle 2. The left rear wheel 46RL is located at the left rear of the vehicle 2. "Rear" refers to the direction of vehicle 2 reversing, which is the downward direction in Figure 1.
[0022] The right rear brake 44RR is located on the right rear wheel 46RR. The right rear brake 44RR operates based on a braking signal input from the brake ECU 22 and applies braking force to the right rear wheel 46RR. The left rear brake 44RL is located on the left rear wheel 46RL. The left rear brake 44RL operates based on a braking signal input from the brake ECU 22 and applies braking force to the left rear wheel 46RL.
[0023] The brake ECU 22 is a control device that outputs braking signals to each brake in order to generate the desired braking force. The brake ECU 22 is a computer having components such as an interface for sending and receiving signals, a memory for storing information, and a CPU for performing calculations. The brake ECU 22 receives a brake operation signal that is output when the brake pedal 34 is operated. The brake ECU 22 receives a control signal from the EVC 10. The brake ECU 22 receives a steering signal from the EPS 20. The brake ECU 22 calculates a braking signal by performing calculations as appropriate based on the brake operation signal, the control signal, and the steering signal. The brake ECU 22 inputs the braking signal to the right front brake 44FR, the left front brake 44FL, the right rear brake 44RR, and the left rear brake 44RL.
[0024] The front motor generator 26A (equivalent to a rotating electric machine and the first drive source) functions as a motor that generates driving force and also functions as a generator that recovers regenerative energy. The front motor generator 26A is rotated by the alternating current output from the front inverter 24A and generates driving torque. The generated driving torque is distributed and transmitted to the right front wheel 46FR and the left front wheel 46FL via the differential gear 42A.
[0025] The rear motor generator 26B (equivalent to a rotating electric machine and the second drive source) functions as a motor that generates driving force and also as a generator that recovers regenerative energy. The rear motor generator 26B is rotated by the alternating current output from the rear inverter 24B and generates driving torque. The generated driving torque is distributed and transmitted to the right rear wheel 46RR and the left rear wheel 46RL via the differential gear 42B.
[0026] The front inverter 24A converts the DC current supplied from the battery 50 via the SMR 51 into AC current and supplies it to the front motor generator 26A at the desired frequency and voltage. Based on the front required torque Tf (corresponding to the first required torque) input from the EVC 10, the front inverter 24A supplies power corresponding to the drive torque generated by the front motor generator 26A.
[0027] The rear inverter 24B converts the DC current supplied from the battery 50 via the SMR 51 into AC current and supplies it to the rear motor generator 26B at the desired frequency and voltage. Based on the rear required torque Tr (corresponding to the second required torque) input from the EVC 10, the rear inverter 24B supplies power corresponding to the drive torque generated by the rear motor generator 26B.
[0028] SMR51 is a relay that switches between a state where power is supplied from the battery 50 to the inverters 24A and 24B and a state where power is cut off. The state of SMR51 is controlled by EVC10.
[0029] The EVC 10 (corresponding to the vehicle control unit) is a control unit that provides integrated control of the vehicle 2. The EVC 10 is a microcomputer (computer) having components such as an interface for sending and receiving signals, a memory (ROM, RAM) for storing information, and a CPU for performing calculations. The EVC 10 receives an accelerator operation signal in response to the operation of the accelerator pedal 32. The EVC 10 receives a steering signal from the EPS 20. The EVC 10 receives a braking signal from the brake ECU 22. The EVC 10 receives a motor current signal from the front inverter 24A. The EVC 10 receives a shift position signal in response to the operation of a shift lever (not shown). The shift position signal includes, for example, a D signal to indicate forward movement and an R signal to indicate reverse movement.
[0030] Incidentally, in order to improve the safety of vehicle 2, it is conceivable to monitor the total required torque Tt, which is the sum of the front required torque Tf and the rear required torque Tr. However, when monitoring the total required torque Tt, it is not possible to detect a reverse-sign torque failure where the total required torque Tt is within the normal range, but the signs of the front required torque Tf and the rear required torque Tr are reversed. A reverse-sign torque failure may occur if specific data in the RAM of the EVC 10 changes to an abnormal value. For example, as shown in Figure 2, suppose the EVC 10 fails at time t11, and the front required torque Tf and the rear required torque Tr become abnormal values. However, in a reverse-sign torque failure where the front required torque Tf becomes a positive abnormal value and the rear required torque Tr becomes a negative abnormal value, and the total required torque Tt does not change before and after the failure, the failure cannot be detected even if the total required torque Tt is monitored. If a reversed torque fault occurs, the torque transmitted to the front wheels 46FR and 46FL and the torque transmitted to the rear wheels 46RR and 46RL will be in opposite directions, which may cause the vehicle 2 to behave in an unstable manner. Therefore, the EVC 10 of this embodiment is equipped with a configuration to detect a reversed torque fault.
[0031] Next, the functional configuration of the EVC 10 will be described with reference to Figure 3. The EVC 10 receives the following inputs: front wheel speed signal, rear wheel speed signal, G sensor signal, motor current signal, accelerator operation signal, brake operation signal, shift position signal, and cruise control request signal. The front wheel speed signal includes a signal indicating the rotational speed of the right front wheel 46FR and a signal indicating the rotational speed of the left front wheel 46FL, i.e., a signal indicating the vehicle speed of vehicle 2. The rear wheel speed signal includes a signal indicating the rotational speed of the right rear wheel 46RR and a signal indicating the rotational speed of the left rear wheel 46RL. The G sensor signal is a signal output by a G sensor (not shown) and indicates the acceleration acting on vehicle 2. The motor current signal is a signal indicating the current value flowing to the motor generators 26A and 26B. The cruise control request signal includes the required torque necessary to maintain a constant distance from the preceding vehicle and a constant vehicle speed when cruise control is being executed. The EVC10 also receives signals related to longitudinal G-force, lateral G-force, yaw rate, and steering angle.
[0032] The EVC10 includes a main microcontroller 60, a monitoring IC 67, a driver IC 68, and a CAN driver 69, etc. The main microcontroller 60 includes a vehicle request calculation unit 61, a rear request calculation unit 62, a subtractor 63, a filter / limiting unit 64, a filter / limiting unit 65, a control monitoring unit 70, and a microcontroller monitoring unit 66, etc.
[0033] The vehicle request calculation unit 61 is the part that calculates the vehicle request torque Tv required for the vehicle 2. The vehicle request calculation unit 61 calculates the vehicle request torque Tv based on signals such as the accelerator operation signal, shift position signal, front wheel speed signal, traction control signal, cruise control request signal, and regenerative braking control signal.
[0034] The rear request calculation unit 62 (corresponding to the second request torque calculation unit) calculates the rear request torque Tr when, for example, either one or both of the right front wheel 46FR and the left front wheel 46FL slip, and it determines that the right rear wheel 46RR and the left rear wheel 46RL need to generate driving force for assistance.
[0035] The subtractor 63 subtracts the rear torque Tr calculated by the rear torque calculation unit 62 from the vehicle torque Tv calculated by the vehicle torque calculation unit 61 to obtain the front torque Tf, and inputs the front torque Tf to the filter / limiting unit 64. The vehicle torque calculation unit 61 and the subtractor 63 constitute the first torque calculation unit.
[0036] The filter / limiting unit 64 performs a filter process or limits the amount of change on the front requested torque Tf to prevent shocks, and outputs the processed front requested torque Tf. The filter / limiting unit 65 performs a filter process or limits the amount of change on the rear requested torque Tr input from the rear request calculation unit 62 to prevent shocks, and outputs the processed rear requested torque Tr.
[0037] The control monitoring unit 70 includes a vehicle request redundancy calculation unit 71, a filter / limit redundancy calculation unit 72, a reverse sign torque abnormality detection unit 73, an F / S (fail-safe) unit 74, an adder 75, a total torque abnormality detection unit 76, and an F / S unit 77, etc.
[0038] The vehicle request redundancy calculation unit 71 is the part that calculates the vehicle monitoring torque TvRef for monitoring the vehicle request torque Tv by performing redundant calculations on the vehicle request torque Tv. The vehicle request redundancy calculation unit 71 calculates the vehicle monitoring torque TvRef based on, for example, an accelerator operation signal, a shift position signal, and a front wheel speed signal. The accelerator operation signal, shift position signal, and front wheel speed signal are highly reliable signals detected by redundant sensors. In addition to these signals, the vehicle request redundancy calculation unit 71 may also take into account a reliable cruise control request signal when calculating the vehicle monitoring torque TvRef.
[0039] The filter / limit redundancy calculation unit 72 applies a filter or limit the amount of change to the vehicle monitoring torque TvRef input from the vehicle request redundancy calculation unit 71 to prevent shocks, and outputs the processed vehicle monitoring torque TvRef.
[0040] The reverse sign torque anomaly detection unit 73 detects an anomaly where the sign of the front requested torque Tf input from the filter / limiting unit 64 and the sign of the rear requested torque Tr input from the filter / limiting unit 65 are reversed. The reverse sign torque anomaly detection unit 73 inputs the detection result to the F / S unit 74.
[0041] The F / S unit 74 receives the rear requested torque Tr from the filter / limiting unit 65 and the detection result from the reverse sign torque anomaly detection unit 73. When the F / S unit 74 receives a detection result indicating that the signs of the front requested torque Tf and the rear requested torque Tr are reversed, it outputs the rear requested torque Tr as 0 (i.e., adjusted to a value closer to 0 than before adjustment). On the other hand, when the F / S unit 74 receives a detection result indicating that the signs of the front requested torque Tf and the rear requested torque Tr are not reversed, it outputs the rear requested torque Tr as is. The reverse sign torque anomaly detection unit 73 and the F / S unit 74 constitute the reverse sign adjustment unit.
[0042] The adder 75 adds the rear requested torque Tr input from the F / S unit 74 and the front requested torque Tf input from the filter / limiting unit 64 to obtain the total requested torque Tt, and inputs the total requested torque Tt to the total torque abnormality detection unit 76.
[0043] The total torque anomaly detection unit 76 detects an anomaly where the absolute value of the difference between the total requested torque Tt input from the adder 75 and the vehicle monitoring torque TvRef input from the filter / limit redundancy calculation unit 72 is greater than a threshold. In other words, the total torque anomaly detection unit 76 detects an anomaly where the total requested torque Tt is outside a predetermined range. The predetermined range is the range where the absolute value of the difference between the total requested torque Tt and the vehicle monitoring torque TvRef is less than or equal to a threshold. The total torque anomaly detection unit 76 inputs the detection result to the F / S unit 77.
[0044] The F / S section 77 receives the front demanded torque Tf from the filter / limiting section 64, the rear demanded torque Tr from the F / S section 74, and the detection result from the total torque abnormality detection section 76. When the F / S section 77 receives a detection result indicating that the absolute value of the difference between the total demanded torque Tt and the vehicle monitoring torque TvRef is greater than the threshold value, it sets the front demanded torque Tf and the rear demanded torque Tr to 0 (that is, adjusts the value of the total demanded torque Tt to a value smaller than before adjustment) and outputs them. On the other hand, when the F / S section 77 receives a detection result indicating that the absolute value of the difference between the total demanded torque Tt and the vehicle monitoring torque TvRef is not greater than the threshold value, it outputs the front demanded torque Tf and the rear demanded torque Tr as they are.
[0045] The front demanded torque Tf and the rear demanded torque Tr output from the F / S section 77 are respectively input to the front inverter 24A and the rear inverter 24B via the CAN driver 69.
[0046] Figure 4 is a flowchart showing the reverse sign torque abnormality detection, the total torque abnormality detection, and the procedures for each F / S. This series of processes is executed by the control monitoring section 70, for example, every 10 ms.
[0047] First, it is determined whether the drive point D determined by the combination of the front demanded torque Tf and the rear demanded torque Tr is within the reverse sign hazard region (S10). Specifically, as shown in FIG. 5, the reverse sign hazard region is set to Tf > 0, and Tr < 0, and |Tf| > ΔTf, and |Tr| > ΔTr. ΔTf is a positive predetermined value (corresponding to the first predetermined value), and ΔTr is a positive predetermined value (corresponding to the second predetermined value). Note that the predetermined value ΔTf and the predetermined value ΔTr may be the same or different. Also, the reverse sign hazard region is set to Tf < 0, and Tr > 0, and |Tf| > ΔTf, and |Tr| > ΔTr. That is, it is determined whether the sign of the front demanded torque Tf and the sign of the rear demanded torque Tr are opposite, and the absolute value of the front demanded torque Tf is greater than the predetermined value ΔTf, and the absolute value of the rear demanded torque Tr is greater than the predetermined value ΔTr.
[0048] In the determination in S10, if it is determined that the drive point D is in the reverse sign hazard region (S10: YES), the rear requested torque Tr is adjusted to a value closer to 0 than before the adjustment (S11). For example, as shown in Figure 5, by setting the rear requested torque Tr to 0, the drive point D1 is changed to the drive point D2, and the drive point D3 is changed to the drive point D4. That is, the value of the rear requested torque Tr is adjusted to a value closer to 0 than before the adjustment, provided that the signs of the front requested torque Tf and the rear requested torque Tr are opposite, the absolute value of the front requested torque Tf is greater than a predetermined value ΔTf, and the absolute value of the rear requested torque Tr is greater than a predetermined value ΔTr. Then, the process proceeds to S12.
[0049] On the other hand, if the determination in S10 determines that the drive point D is not in the reverse sign hazard region (S10: NO), then it is determined whether the drive point D is in the acceleration hazard region or the deceleration hazard region (S12). The acceleration hazard region and the deceleration hazard region are set to a range in which the absolute value of the difference between the total required torque Tt and the vehicle monitoring torque TvRef is greater than a threshold. Specifically, as shown in Figure 5, the acceleration hazard region is set to Tt - TvRef > ΔTt1. The deceleration hazard region is set to Tt - TvRef < ΔTt2. The first threshold ΔTt1 is a positive threshold, and the second threshold ΔTt2 is a negative threshold. In Figure 5, |ΔTt2| > |ΔTt1|. Note that |ΔTt2| and |ΔTt1| may be the same. In other words, it is determined whether the total required torque Tt is outside the safe region (corresponding to a predetermined range), and the safe region is the region between the acceleration hazard region and the deceleration hazard region. Furthermore, in the determination in S12, it may be further specified that the duration of the state in which the drive point D is in the acceleration hazard region or the deceleration hazard region exceeds a predetermined time.
[0050] In the determination in S12, if it is determined that the drive point D is in the acceleration hazard region or the deceleration hazard region (S12: YES), the total required torque Tt is adjusted to a value smaller than before the adjustment (S13). For example, as shown in Figure 5, by setting the front required torque Tf and the rear required torque Tr to 0, the drive point D5 is changed to the drive point D6, and the drive point D2 is changed to the drive point D6. Then the process proceeds to S14.
[0051] On the other hand, if the determination in S12 determines that the drive point D is not in either the acceleration hazard region or the deceleration hazard region (S12: NO), the front requested torque Tf and the rear requested torque Tr are transmitted to the front inverter 24A and the rear inverter 24B, respectively (S14). Then, a return is made (RETURN).
[0052] Furthermore, the process in S10 corresponds to the process of the reverse-sign torque abnormality detection unit 73, the process in S11 corresponds to the process of the F / S unit 74, the process in S12 corresponds to the process of the total torque abnormality detection unit 76, and the process in S13 corresponds to the process of the F / S unit 77.
[0053] Figure 6 is a time chart showing the changes in each required torque when a reverse-sign torque failure occurs. Assume that at time t21, the EVC 10 fails and the front required torque Tf and rear required torque Tr become abnormal values. At time t22, the control monitoring unit 70 determines that the drive point D is in the reverse-sign hazard region and sets the rear required torque Tr to 0. As a result, the total required torque Tt becomes equal to the front required torque Tf. At time t23, the control monitoring unit 70 determines that the drive point D is in the acceleration hazard region and sets the front required torque Tf to 0. This ensures the safety of vehicle 2. If the drive point D is not in the acceleration hazard region after the rear required torque Tr is set to 0 at time t22, the front required torque Tf is maintained as is. In this case, vehicle 2 can continue driving.
[0054] Returning to Figure 3, the microcontroller monitoring unit 66 (corresponding to the abnormality detection unit) monitors the control monitoring unit 70, which includes the reverse sign torque abnormality detection unit 73 and the total torque abnormality detection unit 76. In other words, the microcontroller monitoring unit 66 detects abnormalities in the control monitoring unit 70. More specifically, the microcontroller monitoring unit 66 self-diagnoses the ROM and RAM of the main microcontroller 60, including the control monitoring unit 70, and the FLOW and INSTRUCTION of the software implemented on the main microcontroller 60. The microcontroller monitoring unit 66 inputs the self-diagnosis results to the monitoring IC 67.
[0055] The monitoring IC 67 (corresponding to the monitoring unit) cuts off power via the driver IC 68 to the SMR 51 when the self-diagnosis result input from the microcontroller monitoring unit 66 is abnormal, that is, when the microcontroller monitoring unit 66 detects an abnormality in the control monitoring unit 70.
[0056] The embodiment described in detail above has the following advantages.
[0057] The reverse sign torque anomaly detection unit 73 and the F / S unit 74 adjust the value of the rear requested torque Tr to a value closer to 0 than before adjustment when the signs of the front requested torque Tf and the rear requested torque Tr are reversed. Therefore, when the signs of the front requested torque Tf and the rear requested torque Tr are reversed, the difference between the front requested torque Tf and the rear requested torque Tr can be reduced. Thus, even if a reverse sign torque failure occurs, it is possible to suppress the instability of the vehicle 2's behavior. Furthermore, since it is not necessary to redundantly calculate and monitor the magnitude of the front requested torque Tf and the magnitude of the rear requested torque Tr, many new configurations are not required.
[0058] The reverse sign torque abnormality detection unit 73 and the F / S unit 74 set the value of the rear required torque Tr to 0 when the signs of the front required torque Tf and the rear required torque Tr are reversed. With this configuration, the state in which the signs of the front required torque Tf and the rear required torque Tr are reversed can be easily resolved, and the instability of the vehicle 2's behavior can be easily suppressed.
[0059] The reverse-sign torque anomaly detection unit 73 and the F / S unit 74 adjust the value of the rear requested torque Tr to a value closer to zero than before adjustment, provided that the signs of the front requested torque Tf and the rear requested torque Tr are opposite, the absolute value of the front requested torque Tf is greater than a predetermined value ΔTf, and the absolute value of the rear requested torque Tr is greater than a predetermined value ΔTr. With this configuration, the rear requested torque Tr can be adjusted only when there is a high possibility that the behavior of the vehicle 2 will become unstable, and unnecessary adjustments to the rear requested torque Tr can be suppressed. As a result, it is possible to suppress causing discomfort to the driver.
[0060] - The secondary required torque, the rear required torque Tr, is calculated to be smaller than the primary required torque, the front required torque Tf. Therefore, the vehicle 2 is driven primarily by the primary required torque, the front required torque Tf. The reverse sign torque abnormality detection unit 73 and the F / S unit 74 set only the secondary required torque, the rear required torque Tr, to 0 when the signs of the front required torque Tf and the rear required torque Tr are reversed. This suppresses instability in the vehicle 2's behavior while allowing the vehicle 2 to be driven by the primary required torque. Consequently, even if a reverse sign torque failure occurs, the vehicle 2 can continue to run.
[0061] The total torque abnormality detection unit 76 and the F / S unit 77 adjust the value of the total required torque Tt, which is the sum of the front required torque Tf and the rear required torque Tr, to a value smaller than before adjustment if the total required torque Tt is in the acceleration hazard region or the deceleration hazard region (i.e., outside the safety region). Therefore, even if the total required torque Tt is in the acceleration hazard region or the deceleration hazard region, the total required torque Tt can be reduced by setting the rear required torque Tr to 0 by the reverse sign torque abnormality detection unit 73 and the F / S unit 74. Consequently, when the rear required torque Tr is set to 0 by the reverse sign torque abnormality detection unit 73 and the F / S unit 74, it is possible to suppress unintended acceleration or deceleration of the vehicle 2.
[0062] - The monitoring IC 67 shuts off power via the SMR 51 when an abnormality is detected by the microcontroller monitoring unit 66. Therefore, if an abnormality occurs in the reverse-sign torque abnormality detection unit 73 and the F / S unit 74 and there is a risk that the front required torque Tf and rear required torque Tr cannot be adjusted, power to the motor generators 26A and 26B can be shut off. Thus, the safety of the vehicle 2 can be improved.
[0063] Furthermore, the above embodiment can also be implemented with the following modifications. Parts identical to those in the above embodiment are denoted by the same reference numerals, and their descriptions are used accordingly.
[0064] The monitoring IC 67 can be omitted. The microcontroller monitoring unit 66 can also be omitted.
[0065] - In Figure 5, the predetermined value ΔTf can also be set to 0. That is, in the determination in S10 of Figure 4, the condition that the absolute value of the front required torque Tf is greater than the predetermined value ΔTf can be omitted. In Figure 5, the predetermined value ΔTr can also be set to 0. That is, in the determination in S10 of Figure 4, the condition that the absolute value of the rear required torque Tr is greater than the predetermined value ΔTr can be omitted.
[0066] - In the determination in S10 of Figure 4, if it is determined that the drive point D is in the reverse sign hazard region (S10: YES), the negative value of either the front required torque Tf or the rear required torque Tr may be set to 0 (it may also be adjusted to a value closer to 0 than before the adjustment).
[0067] - In the determination in S10 of Figure 4, if it is determined that the drive point D is in the reverse sign hazard region (S10: YES), the front requested torque Tf may be adjusted to a value closer to 0 than before the adjustment. Also, if it is determined that the drive point D is in the reverse sign hazard region (S10: YES), the front requested torque Tf and the rear requested torque Tr may be adjusted to values closer to 0 than before the adjustment. In other words, if the control monitoring unit 70 determines that the drive point D is in the reverse sign hazard region (S10: YES), it is sufficient to adjust at least one of the front requested torque Tf and the rear requested torque Tr to a value closer to 0 than before the adjustment.
[0068] - The front required torque Tf can be designated as a secondary required torque, and the rear required torque Tr can be designated as the primary required torque.
[0069] - Instead of the front motor generator 26A and front inverter 24A in Figure 1, an engine 26C (corresponding to the first drive source) and an engine ECU 24C can be used, as shown in Figure 7. In this case, instead of the EVC 10 in Figure 1, an HVC (Hybrid Vehicle Controller) 10A can be used, as shown in Figure 7. The engine ECU 24C controls the amount of fuel to be burned by the engine 26C based on the front required torque Tf (corresponding to the first required torque) input from the HVC 10A.
[0070] The EVC 10, HVC 10A and its methods described in this disclosure may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the EVC 10, HVC 10A and its methods described in this disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the EVC 10, HVC 10A and its methods described in this disclosure may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.
[0071] The embodiments and their modifications have been described above with reference to specific examples. However, this disclosure is not limited to these specific examples. Modifications made to these specific examples by those skilled in the art are also included within the scope of this disclosure, as long as they retain the features of this disclosure. The elements, their arrangement, conditions, shapes, etc., of each of the aforementioned specific examples are not limited to those illustrated and can be modified as appropriate. The elements of each of the aforementioned specific examples can be combined in different ways as appropriate, as long as no technical inconsistencies arise.
[0072] The following describes the characteristic configurations extracted from each of the embodiments and modifications described above. [Configuration 1] A vehicle control device (10, 10A) for controlling a four-wheel drive vehicle (2) comprising front wheels (46FR, 46FL), a first drive source (26A, 26C) that generates a driving force to drive the front wheels, rear wheels (46RR, 46RL), and a second drive source (26B) that generates a driving force to drive the rear wheels, comprising: a first required torque calculation unit (61, 63) that calculates a first required torque to be required by the first drive source; a second required torque calculation unit (62) that calculates a second required torque to be required by the second drive source; and a reverse sign adjustment unit (73, 74) that adjusts the value of at least one of the first required torque and the second required torque to a value closer to zero than before adjustment when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are reversed. [Configuration 2] The vehicle control device according to Configuration 1, wherein the reverse sign adjustment unit sets the value of one of the first required torque and the second required torque to 0 when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are reversed. [Configuration 3] The vehicle control device according to Configuration 1 or 2, wherein the reverse sign adjustment unit adjusts the value of at least one of the first required torque and the second required torque to a value closer to 0 than before adjustment, provided that the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are reversed, the absolute value of the first required torque is greater than a first predetermined value, and the absolute value of the second required torque is greater than a second predetermined value. [Configuration 4] A vehicle control device according to Configuration 1 or 2, wherein the sub-required torque, which is one of the first required torque and the second required torque, is calculated to be smaller than the main required torque, which is the other, and the reverse sign adjustment unit sets only the sub-required torque to 0 when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are opposite.[Configuration 5] A vehicle control device according to any one of Configurations 1 to 4, further comprising an absolute value adjustment unit (76, 77) that adjusts the value of the vehicle's required torque to a value smaller than before adjustment when the total required torque, which is the sum of the first required torque and the second required torque, falls outside a predetermined range. [Configuration 6] A vehicle control device according to any one of Configurations 1 to 5, further comprising: the first drive source and the second drive source are rotating electric machines; the vehicle is equipped with a system main relay (51) that supplies and cuts off power to the first drive source and the second drive source; an abnormality detection unit (66) that detects an abnormality in the reverse sign adjustment unit; and a monitoring unit (67) that cuts off power using the system main relay when the abnormality is detected by the abnormality detection unit.
[0073] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.
Claims
1. A vehicle control device (10, 10A) for controlling a four-wheel drive vehicle (2) comprising front wheels (46FR, 46FL), a first drive source (26A, 26C) that generates a driving force to drive the front wheels, rear wheels (46RR, 46RL), and a second drive source (26B) that generates a driving force to drive the rear wheels, the vehicle control device comprising: a first required torque calculation unit (61, 63) that calculates a first required torque to be required by the first drive source; a second required torque calculation unit (62) that calculates a second required torque to be required by the second drive source; and a reverse sign adjustment unit (73, 74) that adjusts the value of at least one of the first required torque and the second required torque to a value closer to zero than before adjustment when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are reversed.
2. The vehicle control device according to claim 1, wherein the reverse sign adjustment unit sets the value of one of the first required torque and the second required torque to 0 when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are opposite.
3. The vehicle control device according to claim 1 or 2, wherein the reverse sign adjustment unit adjusts the value of at least one of the first required torque and the second required torque to a value closer to zero than before adjustment, provided that the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are opposite, and the absolute value of the first required torque is greater than a first predetermined value, and the absolute value of the second required torque is greater than a second predetermined value.
4. The vehicle control device according to claim 1, wherein the sub-required torque, which is one of the first required torque and the second required torque, is calculated to be smaller than the main required torque, which is the other, and the reverse sign adjustment unit sets only the sub-required torque to 0 when the sign of the first required torque calculated by the first required torque calculation unit and the sign of the second required torque calculated by the second required torque calculation unit are opposite.
5. The vehicle control device according to claim 2 or 4, further comprising absolute value adjustment units (76, 77) that adjust the value of the total required torque, which is the sum of the first required torque and the second required torque, to a value smaller than the value before adjustment when the total required torque falls outside a predetermined range.
6. The vehicle control device according to any one of claims 1, 2, or 4, wherein the first drive source and the second drive source are rotating electric machines, the vehicle is equipped with a system main relay (51) for supplying and interrupting power to the first drive source and the second drive source, an abnormality detection unit (66) for detecting an abnormality in the reverse sign adjustment unit, and a monitoring unit (67) for interrupting power by the system main relay when the abnormality is detected by the abnormality detection unit.
7. A vehicle control program for controlling a four-wheel drive vehicle (2) comprising front wheels (46FR, 46FL), first drive sources (26A, 26C) that generate driving force to drive the front wheels, rear wheels (46RR, 46RL), and a second drive source (26B) that generates driving force to drive the rear wheels, wherein the vehicle control program causes a computer (10, 10A) to perform the following: a process of calculating a first required torque to be requested from the first drive source; a process of calculating a second required torque to be requested from the second drive source; and a process of adjusting at least one of the values of the first required torque and the second required torque to a value closer to zero than before adjustment if the signs of the calculated first required torque and the calculated second required torque are opposite.
8. A vehicle control method for controlling a four-wheel drive vehicle (2) comprising front wheels (46FR, 46FL), first drive sources (26A, 26C) that generate driving force to drive the front wheels, rear wheels (46RR, 46RL), and a second drive source (26B) that generates driving force to drive the rear wheels, the method comprising causing a computer (10, 10A) to perform the following: a process of calculating a first required torque to be requested from the first drive source; a process of calculating a second required torque to be requested from the second drive source; and a process of adjusting the value of at least one of the first required torque and the second required torque to a value closer to zero than before adjustment if the signs of the calculated first required torque and the calculated second required torque are opposite.