Vehicle control system

Abstract

Vehicle control system that uses an index to refer to a vehicle's (1) driving state based on a vehicle parameter that indicates a movement of the vehicle (1), and subsequently sets a driving characteristic of the vehicle (1) according to the index, with: a disturbance reduction unit configured to derive the index based on the vehicle parameter from which a fluctuation component, which fluctuates due to a condition of a road surface, is damped, characterized in that The disturbance reduction unit is set up to attenuate a disturbance component of a predetermined frequency, which lies within a predetermined frequency band of the fluctuation component, by filtering the fluctuation component using a bandpass filter with a predetermined frequency property to suppress an influence of a disturbance of the fluctuation component on a resulting index. wherein the bandpass filter has a low-pass filter property that filters a differential value of the output value of a wheel speed sensor (19) and a high-pass filter property that filters an output value of a longitudinal acceleration sensor (25).

Description

Background of the invention 1. Field of the invention

[0001] The invention relates to a vehicle control system that is set up to control behavioral characteristics or acceleration / deceleration characteristics (referred to as "vehicle characteristics") of the vehicle, such as a performance characteristic, steering characteristic and suspension characteristic of the vehicle, so that the driving characteristics correspond to a driving environment and the driver's preferences and intention regarding driving. 2. Description of the state of the art

[0002] While vehicle behavior, such as vehicle speed and direction of travel, varies according to the driver's acceleration / deceleration and steering operations, the relationship between the extent of the driver's operation and the extent of change in behavior is determined not only by energy efficiency, such as fuel economy, but also by characteristics such as ride comfort, quietness, and performance required of the vehicle.

[0003] Meanwhile, the environments in which a vehicle operates encompass a wide range of settings and road types, such as urban areas, highways, winding roads, and uphill and downhill sections. Driver preferences and intentions regarding driving vary, as do the impressions the driver receives from the vehicle during a journey. Therefore, an expected driving characteristic is not necessarily maintained when the driving environment changes or the vehicle is driven by a different driver. As a consequence, the vehicle's handling may deteriorate.

[0004] Therefore, a type of vehicle was developed that allows manual selection of driving characteristics, such as a power output (or acceleration) characteristic and a suspension characteristic relating to the vehicle's behavior, by operating a mode selector switch. Specifically, the vehicle is designed to allow manual selection of a driving mode from, for example, a sport mode, in which the vehicle delivers excellent acceleration performance and the suspension is set somewhat firmer; a normal mode, in which the vehicle accelerates with a relatively low wheel speed and has a relatively soft suspension characteristic; and an ECO mode, in which fuel economy or efficiency is prioritized, by operating the switch.

[0005] Additionally, Japanese Patent Application No. 10-77894 (JP-A-10-77894) discloses a system designed to estimate a vehicle's driving orientation based on the vehicle's output actuation amount. The system described in JP-A-10-77894 is designed to determine a maximum throttle valve opening degree, which serves as the vehicle's output actuation amount. If the deviation between the maximum throttle valve opening degree and the throttle valve opening degree after a predetermined time period (when the maximum throttle valve opening degree reaches its maximum value) exceeds a predetermined criterion value, the estimation of driving orientation based on the throttle valve opening degree is prevented.In particular, it is determined, for example, whether a so-called "chip-in" operation is taking place, such as a sudden pressing down and releasing of operations of an accelerator pedal in a short period of time, which occurs depending on the habit of a driver or a road condition, and if it is determined that the "chip-in" operation is taking place, an estimation of the driving direction is prevented.

[0006] Additionally, Japanese Patent Application Publication No. 8-28640 (JP-A-8-28640) describes a control system for a vehicle equipped with a continuously variable transmission (CVT). The control system is configured to detect the gradient of a road (or the gradient resistance of the vehicle) and then filter the detected gradient using a low-pass filter, thereby preventing oscillation of the shift control due to slight variations in the gradient. The systems described in JP-A-06-249007 are designed to modify a driver's driving attitude or driving characteristics based on the longitudinal acceleration of the vehicle or an accelerator operation by the driver.Therefore, by detecting or estimating the vehicle's acceleration behavior, it is possible to estimate the driver's driving orientation and subsequently incorporate this estimated orientation into vehicle behavior control. However, if, for example, the driver performs a driving operation as described in JP-A-10-77894, such as pressing and releasing the accelerator pedal and pressing the brake pedal, the fluctuation component of the vehicle's acceleration due to the influence of such a driving operation is included as a so-called disturbance component, and as a consequence, the accuracy of the driving orientation estimation may decrease.In contrast to the above, for example, when the vehicle travels along a highly uneven road surface, a road surface with a changing gradient, or the like, the fluctuation component of the vehicle's acceleration due to the influence of the road surface is considered a so-called disturbance component, and as a consequence, the accuracy of estimating a driving orientation may decrease. Thus, the existing state of the art still offers scope for improving the accuracy of estimating a driver's driving orientation and adequately considering a driver requirement or driving orientation within a driving characteristic.

[0007] Furthermore, publication US 2009 / 0 043 474 A1 discloses a control device for controlling the stopping of a vehicle, comprising a speed detection device for detecting a speed of the vehicle from detection results of a speed detector, a setpoint setting device for setting a target acceleration of the vehicle depending on the actual speed when the vehicle is automatically stopped, and a control device for controlling an acceleration of the vehicle to the target acceleration. Summary of the invention

[0008] It is an object of the invention to provide a vehicle control system that ensures that the driver's preferences and intentions regarding driving or vehicle driving conditions are faithfully taken into account by driving characteristics, such as the vehicle's behavior or acceleration.

[0009] The above problem is solved according to the invention by a vehicle control system according to claim 1. Further features and advantageous embodiments are shown in the dependent claims.

[0010] One aspect of the invention provides a vehicle control system that obtains an index, which relates a vehicle's driving state based on a vehicle parameter indicating a vehicle's movement, and subsequently sets a vehicle driving characteristic according to the index, with a disturbance reduction unit configured to obtain the index based on the vehicle parameter, from which a fluctuation component, which fluctuates due to the condition of a road surface, is attenuated, wherein the disturbance reduction unit is configured to attenuate a disturbance component of a predetermined frequency, which lies within a predetermined frequency band of the fluctuation component, by filtering the fluctuation component using a bandpass filter with a predetermined frequency characteristic to suppress an influence of a disturbance of the fluctuation component on a resulting index.and wherein the bandpass filter has a low-pass filter property that filters a differential value of the output of a wheel speed sensor, and a high-pass filter property that filters an output of a longitudinal acceleration sensor.

[0011] According to the aforementioned vehicle control system, for example, if the index is obtained based on a vehicle parameter that indicates a movement of the vehicle, such as vehicle speed, vehicle acceleration, and the rotational speed of each wheel, a fluctuation component of the vehicle parameter due to a condition or road surface is mitigated. In other words, for example, the vehicle control system removes a temporary or instantaneous fluctuation component of the vehicle parameter that occurs due to a rough driving operation, such as sudden acceleration, sudden braking, and sudden steering, or due to a change in a road surface condition, such as unevenness of a road surface and the gradient of a hill.Therefore, it is possible to suppress the influence of a fluctuation in the vehicle parameter on the resulting index, even if the influence is not intended by the driver, and as a consequence, the actual behavior of the vehicle can still be adequately reflected in the index. Thus, the vehicle is capable of providing a driving characteristic suitable for a given driving orientation, a driving environment such as a road surface, or the like.

[0012] Furthermore, if the vehicle's behavior is modified based on its acceleration, or if acceleration is factored into the vehicle's behavior, a temporary or instantaneous fluctuation component of the acceleration due to variations in road surface conditions—that is, a fluctuation component in a specific frequency band, which becomes a disturbance—is removed by the bandpass filter compatible with that specific frequency band. Therefore, it is possible to adequately suppress the influence of acceleration fluctuations—that is, the disturbance component of the fluctuation—on the resulting index, even though the influence is not intended by the driver. Consequently, the vehicle's actual behavior can still be adequately reflected in the index.

[0013] In the present vehicle control system, the vehicle parameter can include vehicle acceleration.

[0014] According to the aforementioned vehicle control system, if the index is obtained based on vehicle acceleration, any fluctuation component of the acceleration due to the driver's driving operation is attenuated. In other words, the vehicle control system removes, for example, any temporary or instantaneous fluctuation component of the acceleration that occurs due to a rough driving operation, such as prompt acceleration, prompt braking, or prompt steering. Therefore, it is possible to suppress the influence of a fluctuation in acceleration on the resulting index, even if the influence is not intended by the driver, and as a consequence, the actual behavior of the vehicle can still be adequately reflected in the index. Thus, the vehicle is able to provide driving characteristics suitable for a given driving direction, driving environment (such as a road surface), or the like.

[0015] Additionally, the vehicle control system may include a disturbance reduction unit to attenuate a disturbance component of a predetermined frequency in the fluctuation component.

[0016] In the aforementioned vehicle control system, a disturbance component of a predetermined frequency within the acceleration fluctuation component, which arises from driver input, is attenuated. In other words, the fluctuation component of a predetermined frequency is eliminated as a disturbance component. Therefore, a disturbance component of the acceleration that negatively impacts the accuracy of the index is removed, and it is possible to maintain the index while still adequately reflecting the actual behavior of the vehicle.

[0017] Additionally, the filter used in the disturbance reduction unit can be the same filter used in a unit different from the disturbance reduction unit, or it can be different from the filter used in a unit different from the disturbance reduction unit. Furthermore, in the filter used in the disturbance reduction unit, a filter property for a component in a longitudinal direction of the vehicle can differ from a filter property for a component in a transverse direction of the vehicle. Finally, the filter used in the disturbance reduction unit can have a filter property that varies according to a speed range of the vehicle. Brief description of the drawings

[0018] The features, advantages and technical and industrial significance of this invention are described below with reference to the attached drawings, in which the same reference numerals denote the same elements, and in which the following applies: Fig. Figure 1 is a block diagram showing a procedure by which accelerations acquired to obtain a command SPI are filtered by a disturbance reduction unit according to an embodiment of the invention. Fig. Figure 2 is a block diagram showing the procedure by which the accelerations that are captured to obtain a command SPI are filtered by the disturbance reduction unit according to the embodiment of the invention, and is a block diagram of a block diagram based on the block diagram of Fig. 1 of the following section; Fig. Figure 3 is a block diagram showing a further procedure by which accelerations detected to obtain a command SPI are filtered by the disturbance reduction unit according to the embodiment of the invention; - Fig. Figure 4 is an example of a characteristic map that is used when a time constant of a transfer function is specified in the block diagram of Fig. The filter shown in section 1 is set; Fig. Figure 5 is a graph showing recorded longitudinal and lateral accelerations recorded on a wheel friction circle; Fig. Figure 6 is a view showing an example of a fluctuation of an instruction SPI obtained on the basis of a fluctuation of the instantaneous SPI; Fig. Figure 7 is a view to illustrate the time integral of a deviation between the instantaneous SPI and the command SPI and a situation where the integral value is reset; Fig. Figure 8 is a characteristic map that shows the relationships between an instruction SPI and a required maximum acceleration rate; Fig. Figure 9 is a graph showing the relationship at each required rotational speed between a vehicle speed and an acceleration with a required acceleration based on an instruction SPI, and a view illustrating a procedure by which a final instruction rotational speed is obtained based on the graph; Fig. Figure 10 is a graph showing the relationship of each gear stage between a vehicle speed and an acceleration with a required acceleration based on an instruction SPI, and a view illustrating a procedure by which a final instruction gear stage is obtained based on the graph; Fig. Figure 11 is a block diagram of a control system that incorporates a correction gear stage and a correction drive force, obtained on the basis of a command SPI, into a shift control system and a machine output control system in a vehicle equipped with a multi-stage automatic transmission; Fig. Figure 12 is a block diagram of a further control that incorporates a correction gear stage and a correction drive force, obtained on the basis of a command SPI, into a shift control and a machine output control in a vehicle equipped with a staged automatic transmission; Fig. 13 is a block diagram of yet another control that incorporates a correction gear stage and a correction drive force, obtained on the basis of a command SPI, in a shift control and a machine output control in a vehicle equipped with a staged automatic transmission; Fig. Figure 14 is a block diagram of a control system that incorporates a correction translation ratio and a correction support torque, obtained on the basis of a command SPI, into a steering property; Fig. Figure 15 is a block diagram of a control system that incorporates a correction vehicle height, a correction damping coefficient, and a correction spring constant, obtained on the basis of a command SPI, into a suspension property; and Fig. Figure 16 is a view that schematically shows a vehicle in which the embodiment of the invention can be applied. Detailed description of implementation examples

[0019] An embodiment of the invention is described with reference to specific examples. In this embodiment, a vehicle subject to control is accelerated, decelerated, or steered by an operation of the driver. A typical example of the vehicle is an automobile that uses an internal combustion engine or motor as a source of propulsion power. Fig. Figure 16 schematically shows an example of the vehicle. The vehicle 1 is an automobile comprising four wheels, consisting of two steered front wheels 2 and two driven rear wheels 3. Each of these four wheels 2 and 3 is mounted on a vehicle body (not shown) via a suspension device 4. Each suspension device 4, like a general known suspension device, consists in principle of a spring and a shock absorber (damper). Fig. Figure 16 shows the shock absorbers 5. Each shock absorber 5 produces a spring effect by utilizing the flow resistance of a fluid, such as a gas or a liquid, and is capable of changing this flow resistance through an actuator, such as a motor 6. This means that if the flow resistance of each shock absorber is increased, the vehicle body can be compressed, providing a so-called firm ride. Furthermore, the handling of the vehicle 1 becomes less comfortable and provides a more sporty feel. It should be noted that the vehicle 1 can be equipped to adjust its ride height by adding or removing pressurized gas to or from these shock absorbers 5.

[0020] Braking devices (not shown) are provided for the corresponding front and rear wheels 2 and 3. The braking devices can be operated to apply a braking force to the corresponding front and rear wheels 2 and 3 when a brake pedal 7 attached to the driver's seat is pressed down.

[0021] The drive shaft of vehicle 1 is a generally known source of drive power, such as an internal combustion engine, a motor and a combination of these. Fig. Figure 16 shows an example of the vehicle 1, which is equipped with an internal combustion engine (engine) 8. A throttle valve 10 for controlling an intake air flow rate is arranged in an intake duct 9 of the engine 8. The throttle valve 10 is an electronic throttle valve. The throttle valve 10 is opened or controlled, for example, by an electrically controlled actuator 11, such as an electric motor or an electromagnetic valve, in order to adjust the degree of opening. Furthermore, the actuator 11 operates according to the depressor range of an accelerator pedal 12 located at the driver's seat, i.e., an accelerator actuation range, in order to adjust the throttle valve 10 to a predetermined degree of opening (throttle opening degree).

[0022] The relationship between accelerator pedal travel and throttle opening can be appropriately adjusted. If the relationship between these approaches a one-to-one ratio, the driver experiences a stronger, more direct feel, and therefore the driving characteristic of vehicle 1 becomes sporty. Conversely, if the relationship between accelerator pedal travel and throttle opening is adjusted so that the throttle opening is relatively smaller than the accelerator pedal travel, the driving characteristic of vehicle 1 becomes smoother. When the motor is used as a drive power source, a power control system, such as an inverter and converter, is provided instead of the throttle valve 10.The current control is designed to adjust an supplied current according to an accelerator actuation range, and to appropriately change the relationship of a current value with respect to an accelerator actuation range, that is, the behavioral characteristic or driving characteristic.

[0023] A transmission 13 is coupled to an output side of the machine 8. The transmission is configured to appropriately change the ratio between an input speed and an output speed, that is, a gear ratio. The transmission 13 is, for example, a generally known transmission, such as a stepped automatic transmission, a continuously variable transmission of the belt type, or a continuously variable transmission of the torsion type. Therefore, the transmission 13 includes an actuator (not shown). The transmission 13 is configured to change the gear ratio in steps or continuously by appropriately controlling the actuator.

[0024] In the transmission control system 13, a shift map, which defines a gear ratio depending on a state of the vehicle 1, such as vehicle speed and accelerator pedal actuation range, is provided beforehand, and shift control is executed according to this shift map. Alternatively, a target output is calculated based on the state of the vehicle 1, such as vehicle speed and accelerator pedal actuation range, a target engine speed is obtained from the target output and an optimal fuel efficiency curve, and then the shift control is executed to achieve the target engine speed.

[0025] In the shift control according to the embodiment of the invention, it is possible to select either a fuel efficiency priority control or a drive force increase control for the basic shift control described above. A fuel efficiency priority control is a control for upshifting at a relatively low vehicle speed, or a control for using a relatively high-speed-side gear ratio (low gear ratio) at a low vehicle speed. Conversely, a drive force increase control or acceleration characteristic enhancement control is a control for upshifting at a relatively high vehicle speed, or a control for using a relatively low-speed-side gear ratio (high gear ratio) at a high vehicle speed.These controls can be implemented, for example, by changing a switching map, correcting a drive request amount, or correcting a calculated transmission ratio.

[0026] It should be noted that a transmission mechanism, such as a torque converter equipped with a locking clutch, may be provided for the vehicle 1 between the machine 8 and the gearbox 13 if necessary. In this configuration, an output shaft of the gearbox 13 is coupled to the rear wheels 3 via a differential 14, which is a final reduction gearbox.

[0027] A steering device 15 rotates the direction of the front wheels 2 for a steering operation. The steering device 15 comprises a steering linkage 17 and an assistance mechanism 18. The steering linkage 17 transmits the rotational movement of a steering wheel 16 to the right and left front wheels 2. The assistance mechanism 18 assists the steering angle or steering force of the steering wheel 16. The assistance mechanism 18 includes an actuator (not shown) and is capable of adjusting the level of assistance provided by the actuator. In particular, if the level of assistance is reduced, the relationship between a steering force and an actual rotational force of the front wheels 2 approximates a one-to-one relationship; that is, the relationship between a steering angle and an actual cornering angle of the front wheels 2 may approximate a one-to-one relationship.As a consequence, the driver experiences a so-called increased direct feeling of steering, and the driving characteristics of vehicle 1 become a so-called sporty feeling.

[0028] It should be noted, although not specifically shown in the drawing, that vehicle 1 is equipped with an anti-lock braking system (ABS), a traction control system (TRC), a vehicle stability control system (VSC), and the like, for stabilizing its behavior or position. The vehicle stability control system (VSC) comprehensively controls these systems. These systems are generally known. These systems are designed to reduce the braking force acting on wheels 2 and 3, or to apply a braking force to wheels 2 and 3 based on a difference between the vehicle body speed and the wheel speed, and simultaneously control an engine torque to prevent wheel lock-up or slippage, thereby stabilizing the behavior of vehicle 1.Additionally, the vehicle 1 may be equipped with a navigation system capable of receiving data related to a road or a planned route (i.e., driving environment), and / or may have a switch for manually selecting a driving mode, such as a sport mode, a normal mode, and a low-fuel-consumption mode (ECO mode). Furthermore, the vehicle 1 may include a four-wheel drive (4WD) mechanism capable of modifying driving characteristics, such as hill-climbing performance, acceleration performance, and cornering performance.

[0029] Furthermore, the vehicle includes 1 various sensors that obtain data for controlling the engine 8, the transmission 13, the shock absorbers 5, the suspension devices 4, the support mechanism 18, the ABS, TRC, VSC, and the like, as described above. The sensors include, for example, a wheel speed sensor 19, an accelerator pedal travel sensor 20, a throttle opening sensor 21, a brake pedal travel sensor 22, an engine speed sensor 23, an output speed sensor 24, a steering angle sensor 25, a longitudinal acceleration sensor 26, a lateral acceleration sensor 27, a yaw rate sensor 28, a roll angle sensor 36, and the like. The wheel speed sensor 19 detects the rotational speed (wheel speed) of each of the front and rear wheels 2 and 3. The accelerator pedal / accelerator actuation circumference sensor 20 detects the depressing circumference of the accelerator pedal 12. The throttle opening degree sensor 21 detects the opening degree of the throttle valve 10.The brake pedal travel sensor 22 detects the travel circumference of the brake pedal 7. The machine speed sensor 23 detects the rotational speed of the machine 1. The output speed sensor 24 detects the output speed of the transmission 13. The steering angle sensor 25 detects the steering angle of the steering wheel 16. The longitudinal acceleration sensor 25 detects the acceleration in the longitudinal direction (front-to-rear direction) of the vehicle 1 (longitudinal acceleration Gx). The lateral acceleration sensor 27 detects the acceleration in the lateral direction (transverse direction) of the vehicle 1 (lateral acceleration Gy). The yaw rate sensor 28 detects the yaw rate of the vehicle 1. The tilt angle sensor 36 detects the gradient of a road surface.It should be noted that the acceleration sensors 26 and 27 can be shared with an acceleration sensor used in vehicle behavior control, such as the aforementioned ABS and VSC, and, if the vehicle 1 is equipped with an airbag, the acceleration sensors 26 and 27 can be shared with an acceleration sensor provided for controlling the application of the airbag. Furthermore, the longitudinal and lateral accelerations Gx and Gy can be obtained by splitting a value detected by an acceleration sensor, which is inclined at a predetermined angle (for example, 45°) with respect to the longitudinal direction of the vehicle on a horizontal plane, into a longitudinal acceleration and a lateral acceleration.Furthermore, instead of measuring the longitudinal and lateral accelerations Gx and Gy with a sensor, these accelerations can be calculated based on the accelerator pedal actuation range, vehicle speed, road load, steering angle, and the like. A composite acceleration, as described below, is not limited to acceleration that includes acceleration components in multiple directions, such as the acceleration component in the longitudinal direction of the vehicle and the acceleration component in the lateral direction. Acceleration in only one direction can also be used as the composite acceleration. For example, acceleration in the longitudinal direction of the vehicle alone can be used as the composite acceleration.

[0030] The aforementioned sensors 19 to 28 are configured to transmit detected signals (data) to an electronic control unit (ECU) 29. The electronic control unit 29 is configured to perform a calculation based on this data and previously stored data and programs, and subsequently output the calculated results as control command signals to the systems described above or to the actuators of these systems.

[0031] As described above, the vehicle control system according to the embodiment of the invention is configured to consider or incorporate the driving state of the vehicle 1 into a behavioral control system. Here, the driving state of the vehicle 1 is expressed by longitudinal acceleration, lateral acceleration, yaw acceleration, roll acceleration, or a resultant acceleration (i.e., composite acceleration) of some of these accelerations in several directions. This means that when the vehicle 1 is caused to travel at a target speed or in a target direction, or when the behavior of the vehicle 1, which is influenced by a driving environment such as a road surface, returns to an initial state, accelerations in several directions typically occur in the vehicle 1.Therefore, in light of this situation, the driving environment or driving orientation may be taken into account to some extent in the driving state of vehicle 1. Based on the foregoing background, the control system according to the embodiment of the invention is configured to take the driving state of vehicle 1 into account or to integrate it into a behavioral control system via vehicle 1.

[0032] Additionally, the behavior of the vehicle 1 includes acceleration characteristics, cornering characteristics, suspension stiffness of the suspension devices 4 (i.e., the extent of compression / rebound and the tendency for compression / rebound to occur), the extent of roll, the extent of pitch, and the like. The control system according to the embodiment of the invention is configured to modify the driving characteristics represented by the aforementioned characteristics based on the driving conditions described above.In this case, the driving characteristics can be changed by using an acceleration in a particular direction or a compound acceleration, which is an example of the driving condition described above; however, to reduce an unpleasant sensation, an index can be used which is obtained by correcting the acceleration or compound acceleration described above.

[0033] As an example of the index, a Sportiness Performance Index (SPI) is described. The Sportiness Performance Index (SPI) is the index that indicates the driver's intention or driving condition. The Sportiness Performance Index that can be applied in the embodiment of the invention is an index obtained by combining accelerations in several directions (in particular, their absolute values). The Sportiness Performance Index is, for example, an acceleration that combines the longitudinal acceleration Gx and the lateral acceleration Gy as an acceleration that is significantly related to the behavior in the direction of travel. For example, the Sportiness Performance Index is calculated by the following mathematical expression. Instantaneous−SPI=(Gx2+Yy2)1 / 2

[0034] Here, the "instantaneous SPI" refers to an index calculated based on accelerations in the corresponding directions at intervals of each moment during the movement of vehicle 1, and is a so-called physical quantity. It should be noted that the "interval of each moment" means each point in time of a repetition, where acceleration measurements and the calculation of an instantaneous SPI based on these measurements are performed repeatedly at predetermined time cycles.

[0035] Additionally, within the longitudinal acceleration Gx used in the preceding mathematical expression, at least one of the acceleration-side and deceleration-side accelerations (i.e., decelerations) can be subjected to a normalization or weighting operation. This means that in an ordinary vehicle, the deceleration-side acceleration is greater than the acceleration-side acceleration; however, the difference is almost imperceptible or undetectable to the driver. In most cases, the driver perceives that the acceleration-side and deceleration-side accelerations are approximately equal.Normalization is a process of correcting such a difference between an actual value and a feeling perceived by the driver, and is a process of increasing the acceleration-side acceleration or decreasing the deceleration-side acceleration for the longitudinal acceleration Gx.

[0036] More precisely, the ratio of the maximum values ​​of these accelerations is obtained, and the acceleration-side or deceleration-side acceleration is multiplied by this ratio. Similarly, the weighting operation can be performed to correct the deceleration-side acceleration with respect to the lateral acceleration. In summary, the weighting operation serves to perform a correction, for example, by assigning a weight to at least one of the longitudinal (forward and backward) accelerations, so that the maximum acceleration in each direction lies on a circle of a given radius, as in the case where the longitudinal and lateral forces that can be produced by a wheel are represented by a wheel friction circle.Through the normalization and weighting operations described above, the extent to which acceleration and deceleration are taken into account by the vehicle's characteristics becomes different. For example, a speed-reducing longitudinal acceleration and a speed-increasing longitudinal acceleration can be subjected to the weighting operation, such that the extent of the influence of the speed-increasing longitudinal acceleration becomes greater than the extent of the influence of the speed-reducing longitudinal acceleration.

[0037] In this way, the actual acceleration and the sensation perceived by the driver differ depending on the direction of the acceleration. For example, it is conceivable that such a difference exists between acceleration in the yaw or roll direction and in a longitudinal direction. Furthermore, in the embodiment of the invention, the control system can be configured to vary the extent to which accelerations in different directions are taken into account in the driving characteristics; in other words, the extent of a change in driving characteristics based on acceleration in one direction differs from the extent of a change in driving characteristics based on acceleration in another direction.

[0038] Fig. Figure 5 shows an example of a wheel friction test circle on which the lateral accelerations Gy detected by the sensor and the longitudinal accelerations Gx, after the normalization and weighting operations described above, are recorded. This is an example where a vehicle is driving on a test track simulating a typical road. Fig. 5. It can be observed that, as a general tendency, the lateral acceleration Gy is likely to be just as large when the vehicle is decelerated to a large extent, and the longitudinal acceleration Gx and the lateral acceleration Gy occur along the wheel friction circle.

[0039] Furthermore, in this embodiment of the invention, a command SPI is obtained from the aforementioned instantaneous SPI. The command SPI is an index used in the control system to modify the driving characteristics and is configured to increase immediately with an increase in the instantaneous SPI, which serves as the basis for calculating the command SPI, and conversely, to decrease with a delay when the instantaneous SPI decreases. In particular, in this embodiment of the invention, the command SPI is configured to decrease based on a factor indicating that a predetermined condition is met. Fig. Figure 6 shows a fluctuation of the instruction SPI, which is obtained based on a fluctuation of an instantaneous SPI. In the example shown here, the instantaneous SPI is represented by... Fig. Five recorded values ​​are specified; whereas the command SPI is set to a local maximum value of the instantaneous SPI and is held at the last value until a predetermined condition is met. That is to say, in the embodiment of the invention, the command SPI is an index that increases rapidly and decreases relatively slowly.

[0040] More precisely, during a period T1 after a start of a control system, the following applies: Fig. 6. For example, when the vehicle decelerates and corners, the instantaneous SPI obtained through the fluctuation in acceleration rises and falls; however, the instantaneous SPI greater than the last local maximum occurs before the predetermined condition described above is satisfied, so the command SPI increases in a stepwise manner. In contrast to t2 or t3, for example, when the vehicle, having cornered and accelerated, begins to drive straight ahead and accelerate, the command SPI decreases because a condition to lower the command SPI is satisfied. Therefore, the condition to reduce the command SPI is satisfied when a condition in which the command SPI is held at the previous large value is not assumed to reflect the driver's intention.In this embodiment, the condition is fulfilled after a specified time has elapsed.

[0041] Specifically, the condition under which the command SPI is held at the previous value is not assumed to reflect the driver's intention. This condition arises when the deviation between the command SPI held at the previous value and the instantaneous SPI occurring in the interim is relatively large, and this deviation continues to be large. Consequently, the command SPI is not reduced due to the instantaneous SPI resulting, for example, from the driver's operation of temporarily releasing the accelerator pedal 12, such as when the vehicle is being steered to perform a turn and accelerate.If a condition exists where, for example, the instantaneous SPI resulting from the driver's operation of continuously releasing the accelerator pedal is lower than the held command SPI, and persists for a predetermined time period, for example, when the vehicle decelerates incrementally, then a condition for reducing the command SPI is determined to be met.

[0042] In this way, the condition for reducing the command SPI can be a duration during which the instantaneous SPI is lower than the command SPI. Additionally, to accurately reflect a current driving state in the command SPI, it is applicable for the condition to reduce the command SPI to be met when a time integral (or an accumulated value) of a deviation between the held command SPI and the instantaneous SPI reaches a predetermined threshold. It should be noted that the threshold can be appropriately set through a driving experiment or a simulation performed according to the driver's intent. When the latter time integral is used, the command SPI is reduced, taking into account a deviation between the command SPI and the instantaneous SPI and a time period, thus enabling control to modify the driving characteristics while still adequately reflecting a current driving state or behavior.is integrated.

[0043] It should be noted that in the Fig. In the example shown in Figure 6, the time period during which the command SPI is held until t2 is longer than the time period during which the command SPI is held until t3; however, this is because the following control is set up to be executed. That is, the command SPI is increased and held at the last stage of the period T1 described above, and subsequently the instantaneous SPI increases at t1 before the condition described above for decreasing the command SPI is met, and furthermore, the integral value is a deviation between the held command SPI and the instantaneous SPI less than or equal to a predetermined value. It should be noted that the predetermined value may be appropriately set by experiment or simulation performed according to the driver's intent, or in consideration of a calculation error of the instantaneous SPI.

[0044] In this way, the fact that the instantaneous SPI is close to the held command SPI means that the vehicle is being brought into an acceleration / deceleration state and / or a cornering state that generated the instantaneous SPI on which the held command SPI is based, or into a condition close to the above. This means that even if a certain time period has elapsed after the command SPI is increased to the held value, the driving state is approximately the same as it was before that time period expired. Therefore, even if the instantaneous SPI is lower than the held command SPI, the time required to fulfill the condition described above for decreasing the command SPI is extended in order to maintain the last command SPI.A control or process for extending the duration can be carried out in such a way that an integrated value (accumulated value) of an elapsed time as described above, or an integral value of a deviation between the command SPI and the instantaneous SPI as described above, is reset, and then the accumulation of an elapsed time or integration of the deviation is resumed, the accumulated value or integral value is reduced by a predetermined amount, or an accumulation or integration is interrupted for a constant time period, or the like.

[0045] Fig. Figure 7 is a time graph illustrating the integration of a deviation between the command SPI described above and the instantaneous SPI, and the time at which the integral value is reset. It should be noted that the hatched area in Fig. 7 corresponds to an integral value of the deviation. In the time diagram of Fig. At point 7, the integral is reset at t11, where the deviation between the instantaneous SPI and the command SPI is less than or equal to a predetermined value Δd, and then integration of the deviation is restarted. Therefore, even if the duration during which the command SPI is held at a predetermined value is extended, the condition for decreasing the command SPI is not met, so the command SPI is held at its last value. Subsequently, after integration resumes, if the instantaneous SPI becomes larger than the held command SPI, the command SPI is updated to the larger value corresponding to the instantaneous SPI and then held at that value, and the integral described above is reset.

[0046] When determining whether the condition for reducing the command SPI is met, based on the aforementioned integral value, it is desirable to vary the magnitude or slope of the reduction. The integral value described above is obtained by integrating the deviation between the held command SPI and the instantaneous SPI with respect to time. Therefore, if the deviation is large, the integral value reaches the predetermined value in a short time period, and subsequently, the condition for reducing the command SPI is met. Conversely, if the deviation is small, the integral value described above reaches the predetermined value in a relatively long time period, and subsequently, the condition for reducing the command SPI is met.

[0047] Therefore, for example, the magnitude or slope of the reduction in command SPI can be varied according to the elapsed time until the condition for reducing command SPI is met. If the aforementioned condition is met within a short time, this means that the width of the decrease in instantaneous SPI relative to the held command SPI is large, and the command SPI deviates significantly from the driver's intention at that time. Subsequently, in such a case, the command SPI will decrease at a high rate or steep slope. Conversely, if the elapsed time period during which the condition for reducing command SPI is met is relatively long, the width of the decrease in instantaneous SPI relative to the held command SPI is small, so the command SPI cannot deviate significantly from the driver's intention at that time.In such a case, the command SPI is gradually reduced at a low rate or small gradient. This quickly and accurately corrects any discrepancy between the command SPI used to set a driving characteristic and the driver's intention, allowing the vehicle's driving characteristic to be adjusted to match the driving conditions.

[0048] The command SPI described above indicates the driving state of vehicle 1 and includes a driving environment, such as a road surface gradient, the presence or absence of a curve and the curve's shape, and the driver's driving orientation. This is because the acceleration of vehicle 1 varies depending on the condition of the road, acceleration / deceleration, and steering operations performed by the driver, based on the condition of the road and also according to these operations. The control system according to the embodiment of the invention is configured to use the command SPI for controlling the driving characteristics of vehicle 1.

[0049] In addition, the driving characteristics in the exemplary embodiment of the invention include acceleration characteristics, steering characteristics, suspension characteristics, noise characteristics, and the like. These characteristics can be appropriately adjusted such that the control characteristics of the throttle valve 10 described above, the shifting characteristics of the transmission 10, the damping characteristics of the shock absorber 5 of each suspension device 4, the support characteristics of the support mechanism 18, and the like, are modified by assigned actuators. A change in the driving characteristics is generally such that, when the command SPI increases, the vehicle is capable of achieving a so-called sportier driving experience.

[0050] As an example of changing the driving characteristics, an example is given in which the acceleration characteristic of vehicle 1 is changed according to the command SPI, with reference to Fig. 8 described. That is, an example is described in which a required maximum acceleration rate is obtained in connection with the command SPI, which was set as described above. In Fig. Section 8 defines the required maximum acceleration rate as a drive force range. For example, a required maximum acceleration rate of 100% indicates that the maximum acceleration achievable by vehicle 1 is possible, and a gear ratio at which the engine speed is at its maximum, or the highest gear ratio (gear ratio at the lowest vehicle speed), is set for transmission 13. Additionally, a required maximum acceleration rate of 50%, for example, indicates that half of the maximum acceleration achievable by vehicle 1 is possible, and a medium gear ratio is set for transmission 13.

[0051] In the Fig. As shown in example 8, if the instruction SPI increases, the required maximum acceleration rate also increases. The solid line in Fig. The specified basic property is obtained by calculating the relationship between an instruction SPI and a required maximum acceleration rate based on data obtained when vehicle 1 is actually driven, and includes appropriate corrections through actual driving or simulation. If a property line is set on a side where the required maximum acceleration rate is greater than that of the basic property, the instantaneous acceleration of vehicle 1 can be relatively large, so the property is a so-called sporty driving property or a sporty acceleration property.Conversely, if the property line is set on a side where the required maximum acceleration rate decreases, the instantaneous acceleration of vehicle 1 can be relatively small, so the property is a so-called comfortable driving property or a comfortable acceleration property. These adjustments (that is, confirming or adjusting) can be made appropriately according to the desired level of serviceability for vehicle 1. It should be noted that the reason the required maximum acceleration rate becomes zero in the base property when the command SPI is greater than zero is because a low-speed driving condition exists, such as driving in a traffic jam or driving the vehicle into a garage, and is not considered in the control for setting or changing the driving properties.

[0052] A control system for modifying the acceleration characteristic by considering the aforementioned required maximum acceleration rate in the shifting characteristic of the transmission 13 is described. In the vehicle 1, equipped with a continuously variable transmission (CVT) as transmission 13, or a hybrid vehicle capable of controlling the engine speed via a motor, a target output is calculated based on a vehicle speed and a drive request amount. Subsequently, a control system is implemented to achieve the engine speed that meets the target output. The relationship between a vehicle speed and an acceleration at each required engine speed is described in Fig. Shown in 9. The command-line SPI based on Fig. The maximum required acceleration rate obtained is related to the relationship in Fig. 9 added. For example, the required maximum acceleration rates of 100% and 50% are added, and indicated by the wide solid lines in Fig. 9 is specified. Therefore, the rotational speed, which is specified by a line passing through an intersection of a line representing a required maximum acceleration obtained from the command SPI and a line representing a vehicle speed at a present time, is a required rotational speed.

[0053] The vehicle 1 equipped with transmission 13, which with reference to Fig. As described in section 16, the system includes a basic shift map to control a gear ratio to be set by the transmission 13. For a continuously variable transmission, the shift map sets a gear ratio according to a vehicle speed and an engine speed. The engine speed obtained from a predetermined vehicle speed and a predetermined gear ratio by using the map is a so-called normal speed. This so-called speed is determined using a Fig. Nine obtained engine speeds are compared (speed-coordinated), and the higher speed is selected. This means that a maximum value is chosen. The selected speed is then instructed as a target value, i.e., a target engine speed. In the continuously variable transmission (CVT), shift control is performed in the direction of a gear ratio corresponding to a lower vehicle speed (high gear ratio). Consequently, as the gear ratio increases, and thus the maximum driving force or engine braking force increases, the vehicle's behavior becomes more responsive, providing a sporty feel or adapting to the driver's driving style or the driving environment, such as the condition of a road.It should be noted that the above control can be executed, for example, when a sport mode is selected using a mode override switch installed on the vehicle, and the control can be prevented when, for example, the sport mode is not selected.

[0054] If, on the other hand, transmission 13 is a stepped transmission, a Fig. The control shown in 10 is carried out. In a shift control via the stepped transmission, a target gear stage is determined, and then a control command signal is issued to an actuator of the transmission 13 to set the specified gear stage. Therefore, the relationship between a vehicle speed and a deceleration is in each gear stage. Fig. Figure 10 shows the lines representing the required maximum accelerations of 100% and 50%. These lines represent the maximum required acceleration rates obtained from the command SPI and are indicated by the wide solid lines in Figure 10. Fig. 10 is specified. Therefore, a gear step defined by the line of a gear step closest to the intersection point between a line indicating the maximum required acceleration received from the command SPI and a line indicating a vehicle speed at a present time is a target gear step.

[0055] If control is carried out by the control system according to the embodiment of the invention, the Fig. The system compares the ten obtained target gear positions with a target gear position based on a previously prepared shift map (for example, the gear ratio obtained based on the accelerator operation and vehicle speed) (coordinates gear positions), and then selects the gear position corresponding to the lower vehicle speed range with a high gear ratio. This means that a minimum value is selected. The gear position selected in this way is then instructed as the final gear position. In the transmission, a shift control is performed towards a gear position corresponding to the lower vehicle speed range (high gear ratio).As a consequence, when the gear ratio increases, or when maximum driving force or machine braking force increases, the behavioral control via vehicle 1 becomes rapid, thereby providing a so-called sporty feel, or being appropriate for a driver's driving style or a driving environment, such as the condition of a busy road. It should be noted that such control via vehicle 1, which is equipped with a stepped transmission, can be configured such that a mode selector switch is provided, and the control is executed when a so-called sporty mode is selected via the switch.

[0056] Next, a control system for correcting a gear stage and a driving force and for changing the driving characteristics according to the correction is described, when the control system according to the embodiment of the invention is applied to the vehicle 1, which includes an internal combustion engine as a driving force source and is equipped with a stepped transmission. Fig. Example 11 illustrates how a target gear ratio and target engine torque are derived from a required drive force. In the basic configuration, a required drive force is first calculated from a vehicle speed and an accelerator pedal actuation range (Block B1). A required drive force is determined based on vehicle weight, power output characteristics, and similar factors. The calculation in Block B1 is performed in such a way that a map defining a required drive force with respect to a vehicle speed and accelerator pedal actuation range is provided, and a required drive force is obtained based on this map. Subsequently, a gear ratio is calculated based on the required drive force (Block B2).

[0057] Shift control via the transmission is performed based on a shift map that defines a gear range or upshift and downshift lines using vehicle speed and required drive force as parameters. The gear is then calculated in block B2 based on this previously prepared shift map. The resulting required gear is output to a shift control device (ECT) B3 as a control command signal, and a shift is subsequently executed in the transmission 13. It should be noted that if a locking clutch (LU) is provided in a power transmission path of the vehicle 1, it is determined whether the locking clutch should be engaged or disengaged based on a previously prepared map, and a control signal for engaging or disengaging the locking clutch is also output.

[0058] On the other hand, a required machine torque is calculated based on the required drive force obtained in block B1 and the current gear stage of transmission 13 (block B4). This means that a machine speed is determined based on the gear stage and the vehicle speed, so that a required machine torque can be calculated based on the machine speed and the required drive force. The machine (ENG) 8 is then controlled to generate the required machine torque (block B5) obtained in this way. In particular, the throttle opening degree is controlled.

[0059] As described above, in the control system according to the exemplary embodiment of the invention, if the longitudinal acceleration Gx, the lateral acceleration Gy, or the combined acceleration (which combines these longitudinal and lateral accelerations) is large, the command SPI increases, and consequently, the required maximum acceleration increases. The required maximum acceleration is determined in the switching control as described in [reference to...]. Fig. 10 described above. If the gear selected based on the command SPI in sport mode is a gear corresponding to a lower vehicle speed than the gear in normal mode, the gear corresponding to the lower vehicle speed will be the final command gear. With reference to Fig. The basic configuration described in section 11 serves to execute the shift control in normal mode, so that if the final command gear stage based on the command SPI is a gear stage of an even lower vehicle speed range, the gear stage in the preceding block B2 is obtained and subsequently set as the required gear stage. As a consequence, a relatively high gear ratio can be obtained, thus increasing the instantaneous acceleration characteristic, which serves as the driving characteristic of vehicle 1.

[0060] Additionally, to adjust the acceleration characteristic according to the command SPI, the power output from machine 8 can be increased or decreased. This control is configured such that a corrective drive force is entered in block B1 above, and then the required drive force, determined based on the basic configuration described above, is increased or decreased by the corrective drive force. It should be noted that it is only necessary for the corrective drive force to be determined based on the command SPI described above.For example, it may only be necessary that the relationship between a command SPI and a correction drive force is defined by an experiment or a simulation, and the relationship may be provided beforehand as data in the form of a map or the like, and the correction drive force may be obtained from the command SPI obtained during driving and the data of the correction drive force map, or the like.

[0061] Fig. Figure 11 shows an example where a gear ratio and a required driving force are obtained simultaneously from a vehicle speed and an accelerator pedal actuation range. As described above, the gear ratio of the stepped transmission is controlled based on a vehicle speed and an accelerator pedal actuation range by reference to a shift map that defines gear ratios or upshift and downshift curves. Therefore, on the one hand, the gear ratio is calculated from a vehicle speed and an accelerator pedal actuation range (Block B11), and on the other hand, a required driving force is calculated from the vehicle speed and the accelerator pedal actuation range (Block B12). This calculation of a required driving force is identical to the calculation described above in Block B1, as shown in Fig. 11 shown.

[0062] The required gear level determined in block B11 is transmitted to the shift control unit (ECT) B13, and subsequently a shift control operation is performed in the transmission 13. It should be noted that if a locking clutch (LU) is provided in a power transmission path of the vehicle 1, it is determined whether the locking clutch is to be engaged or disengaged, based on a previously prepared map, and a control signal for controlling the engagement or disengagement of the locking clutch is also output.

[0063] On the other hand, the required machine torque is calculated based on the required drive force determined in block B12 and an actual gear stage of the gearbox 13 (block B14), and then the machine (ENG) 8 is controlled in such a way as to generate the required machine torque thus obtained (block B15). The control in block B14 is the same as the control in block B4, as in Fig. 11 shown, and the control in block B15 is the same as the control in block B5, as shown in Fig. 11 shown.

[0064] In the case of the in Fig. In the configuration shown in Figure 12, if a final command gear ratio based on the command SPI is a gear ratio on the lower end of the vehicle speed spectrum, the gear ratio is obtained from block B11 and subsequently set as the required gear ratio. As a consequence, a relatively high gear ratio is set, thus increasing the acceleration characteristic, which serves as the driving characteristic of vehicle 1. Additionally, a corrective drive force is input into block B12 according to the command SPI, and the required drive force determined by the basic configuration described above is increased or decreased by the corrective drive force.

[0065] Fig. Figure 13 shows an example in which the transmission 13 and the machine 8 are controlled independently based on vehicle speed and accelerator pedal actuation range. This means that a gear ratio is calculated based on vehicle speed and accelerator pedal actuation range (block B21), the calculated required gear ratio is transmitted to the shift control device (ECT) B22, and subsequently the shift control is executed in the transmission 13. These controls are identical to the controls in block B11 and block B13, which are described in Fig. 12 are shown.

[0066] On the other hand, a throttle opening degree is calculated based on an accelerator actuation range (Block B23), and machine 8 is controlled according to the required throttle opening degree (Block B24). It should be noted that if an electronic throttle valve is provided, the relationship between an accelerator actuation range and a required throttle opening degree is generally non-linear. In a state where the accelerator actuation range is relatively small, a variation in the throttle opening degree with respect to a variation in the accelerator actuation range is small; whereas, when the accelerator actuation range is relatively large, the relationship between a variation in the accelerator actuation range and a variation in the throttle opening degree is close to a one-to-one relationship.

[0067] In the case of the in Fig. In the configuration shown in Figure 13, if the final command gear ratio based on the command SPI is still a gear ratio on the lower end of the vehicle speed spectrum, the gear ratio is obtained from block B21 and subsequently set as the required gear ratio. As a consequence, a relatively high gear ratio is set, so the acceleration characteristic, which serves as the driving characteristic of vehicle 1, increases. Additionally, a correction throttle opening value corresponding to the command SPI is entered into block B23, and the required throttle opening value determined based on the base configuration described above is increased or decreased by the correction throttle opening value. Specifically, if the command SPI becomes large, the output characteristic of the drive source with respect to the acceleration operation can be modified (for example, the output characteristic can be increased).

[0068] As described above, in the control system according to the exemplary embodiment of the invention, when the combined acceleration increases based on an intention to accelerate / decelerate, corner, or the like—for example, when the accelerator pedal 12 is pressed for acceleration, when the brake pedal 7 is pressed for deceleration, when the steering wheel 16 is turned for cornering, or the like—the command SPI increases immediately in accordance with the increase in the combined acceleration. As a consequence, excess driving force increases in accordance with the increase in the command SPI, and the required acceleration is generated instantaneously, thus enabling the vehicle to offer a sporty driving characteristic.The above operation is usually perceived by the driver to cause the vehicle to drive in accordance with a driving environment, such as the gradient of a road, in order to possibly take into account a driving orientation or a driving environment in the changed driving characteristics.

[0069] For example, when vehicle 1 travels uphill, it is moving in the opposite direction to the direction of gravitational acceleration. Therefore, the longitudinal acceleration sensor 25 outputs a larger value than the actual acceleration. Thus, when the vehicle accelerates uphill, the instantaneous SPI increases compared to when vehicle 1 is traveling along a flat road without any incline. Consequently, the command SPI also increases, modifying the acceleration property of vehicle 1 to increase the acceleration force. Therefore, a relatively large driving force can be obtained uphill. Conversely, when traveling downhill, the longitudinal acceleration sensor 25 outputs a smaller value than the actual acceleration, so the instantaneous SPI becomes relatively small when the vehicle decelerates downhill.However, when a braking operation is performed to counteract an increase in vehicle speed downhill, the gravitational acceleration is added to the acceleration associated with the braking operation. This results in a relatively large value output by the longitudinal acceleration sensor 25, and consequently, the instantaneous SPI increases, and the acceleration property is modified to increase the maximum acceleration force. Therefore, a relatively large machine braking force can be obtained. Thus, a separate acceleration / deceleration operation for uphill and downhill travel is unnecessary or facilitated, further improving handling. Additionally, a so-called hill climb / downhill control, such as a commonly known control system to prevent a gear ratio from shifting at high vehicle speeds, can be mitigated or eliminated.

[0070] Additionally, in the control system according to the exemplary embodiment of the invention, when the driving characteristics of vehicle 1 are changed based on accelerations in multiple directions, the extent of the generated acceleration, the magnitude of the acceleration, the driving feel perceived by the driver, or the influence of behavior can vary depending on the direction of the acceleration. In light of the foregoing, the control system according to the exemplary embodiment of the invention adapts the extent of the change in driving characteristics based on an acceleration in a predetermined direction (in other words, the way in which it is taken into account in the driving characteristics) differently from an acceleration in another direction, so that it is still possible to adequately change the driving characteristics based on accelerations in multiple directions.

[0071] It should be noted that in the specific example above, when vehicle 1 begins a journey, acceleration occurs in any longitudinal and lateral direction, and the command SPI consequently increases. Conversely, a decrease in the command SPI is relatively delayed, so the command SPI and the required maximum acceleration rate associated with it can be increased according to a time period that elapses after the start of a journey and a certain distance has been traveled. Therefore, it is possible to increase what is known as sportiness.

[0072] In addition, the factor influencing and determining the driving characteristics of vehicle 1 is not only the acceleration characteristic described above, achieved through control via the gear ratio, but also the output characteristic of the machine torque against an acceleration operation, a steering characteristic which is the relationship of a turning angle of the front wheels 2 with respect to a steering angle or a steering force, the damping characteristic of vibrations or a spring constant of each suspension device 4, the cornering characteristic based on a torque distribution ratio between the front and rear wheels in a four-wheel-drive vehicle, and the like. The control system according to the embodiment of the invention can be configured to modify these characteristics based on an index determined from the accelerations.For example, according to the command SPI described above, the output response of machine 8 is adjusted, specifically the rate of throttle opening is adjusted, the assist torque provided by the assist mechanism 18 is adjusted, giving the driver an appropriately direct feel for the steering, the gear ratio of the steering mechanism 15 is adjusted, and the cornering performance is adjusted by modifying the amount of torque distributed to the rear wheels. The control to change each property can be implemented by modifying the output characteristics of the actuators provided in the corresponding mechanisms.

[0073] Furthermore, the control system according to the embodiment of the invention can also be used when the steering characteristic, the suspension characteristic, or the like, which are one of the driving characteristics of the vehicle 1, are changed to a different situation than when the acceleration characteristic or performance characteristic of the vehicle 1 is changed. Fig. Figure 14 is a block diagram illustrating a control system for changing the steering characteristics based on the SPI described above, and schematically shows, for example, an electric power steering (EPS) mechanism that uses a variable-ratio steering gear (VGRS). A linkage 30 is provided to receive a steering force and move rearward and forward in the transverse (lateral) direction of the vehicle. The linkage 30 is engaged with the gear of a VGRS gear unit 31. A VGRS actuator 32 for changing the gear ratio is attached to the VGRS gear unit 31. Additionally, an EPS geared motor 33 is provided to assist movement of the linkage 30 in a steered direction. Furthermore, a gear ratio calculation unit 34 and an assist torque calculation unit 35 are provided.The transmission ratio calculation unit 34 issues a command signal to the VGRS actuator 32 to change the transmission ratio between the linkage 30 and the VGRS gear unit 31. The support torque calculation unit 35 calculates a torque to be output by the EPS geared motor 33 (pressure force applied to the linkage 30) and then outputs the torque as a command signal. This power transmission steering mechanism and calculation units can be those with generally known configurations.

[0074] The detected vehicle speed, steering angle, and steering torque are input as data into the aforementioned calculation units 34 and 35. This data can be obtained from various sensors, which are provided according to the vehicle speed, steering angle, and steering torque. In addition to this, a correction gear ratio is input as data into the gear ratio calculation unit 34. The correction gear ratio is used to correct a command signal to the VGRS actuator 32 and is configured to adjust the command signal to a value corresponding to the command SPI. Specifically, it is only necessary that a map defining a correction gear ratio in accordance with a command SPI is provided beforehand, and the correction gear ratio is obtained from this map.The relationship between an instruction SPI and a correction translation ratio can be appropriately defined where required.

[0075] On the other hand, a correction support torque is input as data into the support torque calculation unit 35 in addition to the vehicle speed, steering angle, and steering torque. The correction support torque is used to correct a command signal to the IPS geared motor 33 and is configured to set the command signal to a value corresponding to the command SPI. Specifically, it is only necessary that a map is pre-prepared which defines a correction support torque corresponding to a command SPI, and a support torque is obtained from the map. The relationship between a command SPI and a correction support torque can be appropriately defined where necessary.

[0076] Therefore, in the case of the in Fig. In the configuration shown in Figure 14, the translation ratio of the VGRS unit 31 is changed according to the command SPI obtained on the basis of accelerations occurring in vehicle 1, and a torque that assists a steering force is changed.

[0077] Additionally shows Fig. 15 An example of a control system for changing the suspension characteristic based on the command SPI described above, and an example set up to control the vehicle height, the damping coefficient of vibrations, and a spring constant by means of a (not shown) variable suspension mechanism. Fig. A computing unit 40 is provided to calculate the required values ​​for vehicle height, vibration damping coefficient, and spring constant. Computing unit 40 consists primarily of a microcomputer. Computing unit 40 is configured to obtain the required vehicle height, damping coefficient, and spring constant by using input data and previously stored data.For example, the following data is input: vehicle speed, a signal detected by a height control sensor of the front right (FR) wheel, a signal detected by a height control sensor of a front left (FL) wheel, a signal detected by a height control sensor of a rear right (RR) wheel, a signal detected by a height control sensor of a rear left (RL) wheel, a signal detected by a vertical G (acceleration) sensor of a front right (FR) wheel, a signal detected by a vertical G (acceleration) sensor of a front left (FL) wheel, a signal detected by a vertical G (acceleration) sensor of a rear right (RR) wheel, a signal detected by a vertical G (acceleration) sensor of a rear left (RL) wheel, and the like. These are identical to those of the generally known system.

[0078] Then, in which Fig. In the example shown in Figure 15, a correction vehicle height, a correction damping coefficient, and a correction spring constant are entered as data for controlling the suspension characteristics. The correction vehicle height is data for correcting the vehicle height according to the command SPI described above. For example, a map is prepared beforehand that defines a correction vehicle height according to a command SPI, and then a correction vehicle height can be obtained from the map.

[0079] Additionally, the correction damping coefficient is data used to correct damping coefficients in devices and mechanisms that provide a vibration damping function, such as shock absorbers. For example, a characteristic map is previously provided that defines a correction damping coefficient in accordance with a command SPI, and a correction damping coefficient can be obtained from the characteristic map.

[0080] Similarly, the correction spring constant data is used to correct the spring constant in each shock absorber 4. For example, a map is pre-prepared that defines a correction spring constant in accordance with a command SPI, and a correction spring constant can be obtained from the map.

[0081] The computing unit 40 is configured to perform a calculation using the data described above, to output the calculated required vehicle height to a vehicle height control unit 41 as a control command signal, and subsequently to control the vehicle height to match the command SPI. Specifically, if the command SPI is relatively large, the vehicle height is controlled to be relatively low. Additionally, the computing unit 40 is configured to output the calculated required damping coefficient to a damping coefficient control unit 42 as a control command signal, and subsequently to control the damping coefficient to match the command SPI. Specifically, if the command SPI is relatively large, the damping coefficient is controlled to be relatively large.Furthermore, the calculation unit 40 is configured to output the calculated required spring constant to a spring constant control unit 43 as a control command signal, and subsequently to control the spring constant in such a way as to correspond to the command SPI. In particular, if the command SPI is relatively large, the spring constant is controlled in such a way as to be relatively large.

[0082] In this way, the control system according to the embodiment of the invention is able to modify the suspension characteristic, which is an example of the driving characteristic, according to a control index, such as a command SPI, which is obtained on the basis of an instantaneous acceleration (in particular a longitudinal acceleration Gx and a lateral acceleration Gy), and to adjust the suspension characteristic to suit the driving condition of the vehicle 1. As a consequence, in the case of so-called smooth driving, in which longitudinal and / or lateral accelerations are relatively small, the suspension characteristic becomes a so-called smooth characteristic in order to improve driving comfort; whereas in the case of so-called fast driving, in which longitudinal and / or lateral accelerations are necessarily relatively high, the suspension characteristic becomes a so-called firm characteristic in order to improve the driving characteristic.

[0083] As described above, the control system according to the exemplary embodiment of the invention is capable of modifying the driving characteristics of the vehicle 1 by appropriately considering or incorporating a driving environment and a driving orientation, and is therefore capable of improving the driving behavior of the vehicle 1. Furthermore, in order to incorporate a driving environment and a driving orientation into a behavioral control system for the vehicle 1 as described above, if a driving orientation is estimated based on the combined acceleration of the vehicle 1, for example, if the combined acceleration of the vehicle 1 varies momentarily or temporarily due to an unintentional driving operation performed by the driver, such as driving on a very bumpy, poor road, or a steep hill, or the like, the fluctuation of the combined acceleration can be considered as a so-called disturbance component.As a consequence, it is likely that it will be difficult to accurately predict a driving direction that corresponds to the driver's intention, i.e., to appropriately set the command SPI described above. If, in the embodiment of the invention, the control system receives an instantaneous SPI for setting a command SPI, particularly to eliminate a disturbance component due to an unintentional driving operation by the driver, the control system filters an acceleration detected by a sensor or a normalized value calculated from a value detected by a sensor, and then calculates an instantaneous SPI based on the filtered composite acceleration.

[0084] In particular, as shown in the block diagrams of Fig. 1 and Fig. 2 shows that first a reference acceleration Gx acca so-called static longitudinal acceleration is calculated, which serves as a reference for a filtering process described below, based on the actuation range of the accelerator pedal 12 (accelerator actuation range) (Block B31). Similarly, a reference deceleration Gx is calculated. dec calculated as a so-called static longitudinal deceleration (that is, a negative acceleration), which is a reference for a filtering described below, based on a brake pedal actuation range 7 (brake actuation range) (block B32).

[0085] It should be noted that at least one, the reference acceleration Gx acc and / or the reference delay Gx decThe values ​​calculated here are preferably subjected to the normalization described above and then used. That is, as described above, in a general car, a deceleration acceleration (i.e., a deceleration) is greater than an acceleration acceleration. Therefore, the reference acceleration Gx is used here. acc subject to normalization, so the value is corrected to increase.

[0086] The calculated reference acceleration Gx acc and reference delay Gx dec Each is subjected to filtering. This means that for the reference acceleration Gx acc For example, filtering is carried out by using the low-pass filter, which is represented by the following transfer function (Block B33). f(s)=1 / (1+s×T21)

[0087] Here is T 21a predetermined time constant taking into account the response property of machine 8, such as a delay in the response of machine 8 to an accelerator operation by the driver, and can also be obtained from a characteristic map which defines the time constant T 21 indicates that, in accordance with the rotational speed of machine 8, as for example in Fig. 4 is shown, it is set.

[0088] Additionally, for the reference delay Gx dec for example, filtering is carried out by using the low-pass filter, which is expressed by the following transfer function (Block B34). f(s)=1 / (1+s×T22)

[0089] Here is T 22 a predetermined time constant taking into account the response property of the braking device, such as a deceleration in response to the braking deceleration to the brake pedal operation by the driver.

[0090] As described above, when a rapid acceleration or braking operation is performed by the driver, a large fluctuation component, that is, a disturbance or disturbance variable that is a fluctuation component of relatively high frequency, momentarily or temporarily appears in the reference acceleration Gx. acc and the reference delay Gx dec occurs. In contrast, as described above, if the reference acceleration Gx acc and the reference delay Gx dec a high-frequency interference component in the longitudinal acceleration, which originates from rough accelerator actuation, brake actuation, or the like, can be removed by filtering through the use of a low-pass filter (in other words, a high-cut filter).

[0091] Subsequently, a preliminary target value Gx* for the longitudinal acceleration is calculated from the acceleration and deceleration filtered as described above (Block B35). That is, as expressed by the following mathematical equation, the filtered value of the reference deceleration Gx dec from the filtered value of the reference delay Gx acc is subtracted to calculate the preliminary target value Gx* of the longitudinal acceleration. Gx*=Gxacc−Gxdec

[0092] On the other hand, a reference lateral acceleration Gy is used. yaw calculated as a so-called static lateral acceleration, which serves as a reference for filtering based on the steering angle of the steering wheel 16 (Block B36). The reference lateral acceleration Gy yaw is calculated, for example, by the following mathematical expression. Gyyaw=Gδr(0)×(1+Tr×s) / (1+2×ζ×s / ωn+s2 / ωn)

[0093] In the preceding mathematical expression (2) ω n a natural frequency in a secondary oscillation system of vehicle 1, ζ is a damping coefficient, Gδr(0) is a frequency transfer function, T r is a time constant. It follows that if the inertial mass of the vehicle is 1 m, the yaw radius of inertia is k, the vehicle speed is V, the wheelbase is 1, and the distance between the center of gravity of the vehicle and the front wheel axle is l. f is the distance between the vehicle's center of gravity and the rear wheel axle l r is the relevant power output of the front wheels 2 K f is the relevant power output of the rear wheels 3 K r is, and the stability factor that indicates the control stability of vehicle 1, A, is the aforementioned natural frequency ω n is expressed by the following mathematical expression. ωn={2×(Kf+Kr) / (m×V)}×(1f×1r / k2)1 / 2×(1+AxV2)1 / 2

[0094] The damping coefficient ζ is expressed by the following mathematical expression. ς={1+k2 / (1f×1r)} / [2×{k2 / (1f×1r)}1 / 2×(1+AxV2)1 / 2]

[0095] The frequency transition function Gδr(0) is expressed by the following mathematical expression. Gδr(0)={1 / (1+AxV2)}×V / 1

[0096] The time constant T r is expressed by the following mathematical expression. Tr=m×1f×V / (2×1×Kr)

[0097] The reference lateral acceleration Gy calculated by the preceding mathematical expression (2) is then yaw for example, subjected to filtering by using the low-pass filter expressed by the following transfer function (Block B37). f(s)=1 / (1+s×T23)

[0098] The filtered lateral acceleration is then set as a preliminary target value Gy* for the lateral acceleration. Here, T 23 a predetermined time constant taking into account the response behavior of the steering device 15, such as a delay in the response of the steering device 15 to the steering operation of the driver.

[0099] As in the case of the reference acceleration Gx described above. acc and reference delay Gx dec It is true that if a rapid steering operation is carried out by the driver, a large fluctuation component, that is, a disturbance or disturbance variable that has a relatively high-frequency fluctuation component, is momentarily or temporarily present in the reference lateral acceleration Gy. yaw occurs. In contrast, as described above, if the reference lateral acceleration Gy yawBy applying a low-pass filter (in other words, a high-cut filter), a high-frequency disturbance component in the lateral acceleration, which results from an unintentional steering operation or the like by the driver, can be removed.

[0100] In this way, if the preliminary target value Gx* for longitudinal acceleration and the preliminary target value Gy* for lateral acceleration are obtained, the preliminary target value Gx* for longitudinal acceleration and the preliminary target value Gy* for lateral acceleration are each further subjected to filtering in order to obtain a target value Gx* filt the longitudinal acceleration and a target value Gy* filt to obtain the lateral acceleration.

[0101] This means that subsequently, as in Fig. As shown in 2, the target value Gx* filtthe longitudinal acceleration is further subjected to filtering by using the low-pass filter, which is expressed by the following transfer function (Block B38). f(s)=1 / (1+sxT24)

[0102] The filtered longitudinal acceleration is the target value Gx* filt The longitudinal acceleration is set here. 24 a predetermined time constant taking into account a pitch resonance frequency of the behavior of vehicle 1 in the pitch direction.

[0103] On the other hand, the preliminary setpoint Gy* of the lateral acceleration is further subjected to filtering by using the low-pass filter, which is expressed by the following transfer function (Block B39). f(s)=1 / (1+sxT25)

[0104] The filtered lateral acceleration is the target value Gy*. filt The lateral acceleration is set here. 25a time constant taking into account a roll resonance frequency of the behavior of vehicle 1 in the roll direction.

[0105] The vehicle 1 exhibits a unique resonant frequency in the pitch direction and a unique resonant frequency in the roll direction, determined by the vehicle body stiffness of the vehicle 1, the damping characteristics of each shock absorber 4, the response of the steering device 15, or similar factors. As described above, when the vehicle is driven in a sport mode, the damping characteristics of each shock absorber 4 are set to be firm, and the response of the steering device 15 is increased. Therefore, if, for example, an acceleration, braking, or steering operation is unintentionally performed by the driver, a resonance in the pitch or roll direction arises in a relatively high-frequency band within the longitudinal or lateral acceleration of the vehicle 1 as a disturbance component.If, in contrast, as described above, the preliminary setpoint values ​​Gx* and Gy* of the longitudinal and lateral acceleration are subjected to filtering by using a low-pass filter (in other words, a high-cut filter) taking into account a pitch resonant frequency and a roll resonant frequency, a high-frequency disturbance component can be removed during driving in a sporty mode.

[0106] Then an instantaneous SPI is generated according to the embodiment of the invention from the setpoint Gx*. filt the longitudinal acceleration and the target value Gy* filt the lateral acceleration, which is obtained as described above, is calculated (Block B40). In particular, by substituting the target value Gx* filt the longitudinal acceleration and the setpoint Gy* filtThe lateral acceleration can be converted into the longitudinal acceleration Gx and the lateral acceleration Gy in the mathematical expression (1) described above, which is the instantaneous SPI. That is, the instantaneous SPI is calculated as follows. Instantaneous SPI=(Gx*filt2+Gy*filt2)1 / 2

[0107] Subsequently, as in the case of the procedure described above, a command SPI is obtained according to the embodiment of the invention based on the instantaneous SPI, which is derived from the setpoint values ​​Gx*. filt and Gy* filt the corresponding accelerations, from which disturbance components were removed by the filtering described above, were calculated.

[0108] Next, the removal of a disturbance component is described as a measure for cases where a fluctuation in acceleration is considered or included as a disturbance component via a momentary or temporary fluctuation in the acceleration of the vehicle 1 due to a change in a road surface condition on which the vehicle 1 is traveling. As described above, the control system according to the embodiment of the invention is capable of modifying the driving characteristics of the vehicle 1 by appropriately considering or incorporating a driving environment or driving orientation, and is capable of improving the driving behavior of the vehicle 1 accordingly.On the other hand, in order to integrate a driving environment or driving orientation into a behavioral control system via vehicle 1 as described above, if a driving orientation is estimated based on the acceleration of vehicle 1—for example, if the acceleration of vehicle 1 fluctuates momentarily or temporarily due to driving on a very bumpy, poor road or a steep hill, or the like—the fluctuation in acceleration can be considered or included as a so-called disturbance component. As a consequence, it may be difficult to estimate precisely a driving orientation that corresponds to the driver's intention, that is, to appropriately set the command SPI described above.If the system described below receives an instantaneous SPI for setting a command SPI, in particular to remove a disturbance component generated due to a change in road surface condition during a journey, the control system is configured to filter a vehicle parameter indicating a movement of the vehicle 1, such as an acceleration obtained from output values ​​of the accelerometers 25 and 26 and the wheel speed sensor 19, by using a bandpass filter that removes a disturbance in a specific frequency band, and to calculate the instantaneous SPI based on the filtered vehicle parameter.

[0109] In particular, as shown by the block diagram of Fig. Figure 3 shows that first a differential value dvx of the output value of the wheel speed sensor 19 is calculated, and then the differential value dvx is subjected to filtering (block B31). In particular, the differential value dvx is subjected to filtering, for example, by using the low-pass filter, which is expressed by the following transfer function. f(s)=1 / (1+sxT1)

[0110] Here, T1 is a predetermined time constant, taking into account, for example, a power transmission characteristic or the like in a drive train from the output shaft of the machine 8 to the rear wheels 3, as in Fig. 16 shown.

[0111] Additionally, the output value Gxsens of the longitudinal acceleration sensor 25 is obtained, and subsequently subjected to filtering (block B32). In particular, the output value Gxsens of the longitudinal acceleration sensor 25 is, for example, filtered by using a high-pass filter, which is expressed by the following transfer function. f(s)=T1 / (1+sxT1)

[0112] As described above, vehicle 1 is equipped with longitudinal acceleration sensor 25, and the longitudinal acceleration of vehicle 1 can be obtained from the output value of the longitudinal acceleration sensor 25. When vehicle 1 travels uphill, a low-frequency fluctuation component of the longitudinal acceleration occurs compared to the case where vehicle 1 travels along a flat road.

[0113] Therefore, if the output value of the longitudinal acceleration sensor 25 is used directly as the longitudinal acceleration of the vehicle 1, as in the case above, a low-frequency fluctuation component of the lateral acceleration, which is not usually expected, can occur as a disturbance component depending on the gradient of a road surface on which the vehicle 1 is traveling. For such a fluctuation component, the output value Gxsens of the longitudinal acceleration sensor 25 is subjected to a high-pass filter (in other words, a low-cut filter) in order to make it possible to remove a specific fluctuation component of a low-frequency band of the output value Gxsens as a disturbance.It should be noted that a specific low-frequency band, from which a disturbance is removed by the high-pass filter, may be set, for example, according to the magnitude of a road surface gradient detected by the tilt angle sensor 36.

[0114] The preliminary target value Gx* for the longitudinal acceleration is calculated from the filtered differential value dvx of the output value of wheel speed sensor 19 and the filtered output value Gxsens of the longitudinal acceleration sensor 25 (block B33). That is, as expressed by the following mathematical expression, the preliminary target value Gx* for the longitudinal acceleration is calculated by adding the filtered value dvx* of the differential value dvx of the output value of wheel speed sensor 19 and the filtered value Gxsens* of the output value Gxsens of the longitudinal acceleration sensor 25. Gx*=dvx*+Gxsens*

[0115] In this way, by adding the filtered value dvx* of the differential value dvx and the filtered value Gxsens* of the output value Gxsens, it is possible to compensate for a gain and a phase deviation between dvx and Gxsens.

[0116] The preliminary setpoint Gx* of the longitudinal acceleration calculated as described above is then subjected to further filtering (Block B34). In particular, the preliminary setpoint Gx* of the longitudinal acceleration is subjected to filtering, for example, by using the low-pass filter, which is expressed by the following transfer function. f(s)=1 / (1+sxT3)

[0117] The filtered longitudinal acceleration is defined as a target value Gx* filtThe longitudinal acceleration is set. Here, T3 is a predetermined time constant taking into account a disturbance variable due to irregularities in a road surface and a disturbance variable included in the output values ​​Gxsens of the longitudinal acceleration sensor 25.

[0118] This means, as described above, that if the irregularities of a road surface on which vehicle 1 is traveling are large, the acceleration of vehicle 1 will fluctuate momentarily or temporarily, and the fluctuation component may be included as a high-frequency disturbance component. Additionally, a disturbance component unavoidably present due to the configuration of a sensor may be included in the output value Gxsens of the longitudinal acceleration sensor 25. Conversely, if the preliminary target value Gx*, calculated from the filtered value dvx* of the differential value dvx and the filtered value Gxsens* of the output value Gxsens as described above, is further subjected to low-pass filtering (in other words, a high-cut filter), then a specific fluctuation component of a high-frequency band of the preliminary target value Gx* of the longitudinal acceleration can be removed as a disturbance.

[0119] On the other hand, the output value Gysens of the lateral acceleration sensor 26 is obtained, and subsequently subjected to filtering (block B35). In particular, the output value Gysens of the lateral acceleration sensor 26 is, for example, subjected to filtering by using the low-pass filter, which is expressed by the following transfer function. f(s)=1 / (1+sxT4)

[0120] The filtered lateral acceleration is defined as a target value Gy*. filt The lateral acceleration is set. Here, T4 is a predetermined time constant, taking into account a disturbance variable contained in the output value Gysens of the lateral acceleration sensor 26.

[0121] This means that, as in the case of the output value Gxsens of the longitudinal acceleration sensor 25 described above, an unavoidable high-frequency disturbance component may be present in the output value Gysens of the lateral acceleration sensor 26 due to the sensor's configuration. Conversely, if the output value Gysens of the lateral acceleration sensor 26 is subjected to low-pass filtering (in other words, high-cut filtering) as described above, a specific fluctuation component of a high-frequency band in the output value Gysens of the lateral acceleration sensor 26 can be removed as a disturbance.

[0122] Then an instantaneous SPI is generated according to the embodiment of the invention from the setpoint Gx*. filt the longitudinal acceleration and the target value Gy* filtthe lateral acceleration, which is obtained as described above, is calculated (Block B36). In particular, by substituting the target value Gx* filt the longitudinal acceleration and the setpoint Gy* filt The lateral acceleration can be converted into the longitudinal acceleration Gx and the lateral acceleration Gy in the mathematical expression (1) described above, which is the instantaneous SPI. That is, the instantaneous SPI is calculated by the following expression. Instantaneous SPI=(Gx*filt2+Gy*filt2)1 / 2

[0123] Subsequently, as in the case of the procedure described above, a command SPI is generated according to the embodiment of the invention based on the setpoint values ​​Gx*. filt and Gy* filt The instantaneous SPI was obtained from the corresponding accelerations, from which disturbance components were removed by the filtering described above.

[0124] The filtering described above can be modified in various ways. For example, a filter for a lateral acceleration component of an acceleration component and a filter for a longitudinal acceleration component of the acceleration component can have filter properties of the same strength or different strengths. Here, the strength of a filter indicates the degree to which a waveform component of an input signal is reduced by processing. If the filter becomes strong, an input signal is processed in such a way that the waveform of an output signal approximates a flat shape. For example, the filter property for a lateral acceleration component can be stronger than the filter property for a longitudinal acceleration component.The above configuration works effectively in a driving environment where a transverse disturbance component is larger than a longitudinal disturbance component. Additionally, for a longitudinal acceleration component, the filtering property of an acceleration component in a braking direction can be stronger than the filtering property of an acceleration component in an acceleration direction (positive in a driving direction). The above configuration works effectively in a vehicle where the control response of a brake is more sensitive than the control response of a drive source.

[0125] Additionally, a filter for an acceleration used to generate a command SPI can be a filter shared with another controller that uses the acceleration, or it can be different from another controller. For example, an acceleration is also used in other controllers, such as ABS, traction control (slip suppression control), and sideslip suppression control (e.g., VSC); however, a command SPI can be generated using an acceleration that has been processed by a second filter with a stronger filtering characteristic than the filtering characteristic of a first filter used in these controllers. In this case, as the filtering characteristic becomes stronger, a delay in the response time occurs.With the above configuration, it is possible to obtain both a disturbance reduction function suitable for sporty performance and a disturbance reduction function, response behavior, and the like that are necessary for further control applications. It should be noted that, to generate a command SPI, the first filter can be used for processing before processing for the second filter.

[0126] Additionally, the same filter can be used regardless of speed, or a filter with different filtering characteristics can be used depending on a speed range. For example, the filtering characteristic can be stronger as the speed approaches a low speed range. With the above configuration, suitable control can be achieved in a starting and low-speed range where the influence of rough driving or road surface tends to be noticeable.

[0127] As described above, the control system according to the embodiment of the invention varies the command SPI, which is obtained as an index indicating the driving state of vehicle 1, at a relatively high rate in one direction to increase the acceleration characteristic of vehicle 1 and in the other direction to decrease the acceleration characteristic of vehicle 1. As a consequence, this can be adequately considered or integrated into a behavioral control system for vehicle 1 using the command SPI.

[0128] Additionally, in the control system according to the embodiment of the invention, the aforementioned command SPI is obtained based on the vehicle parameters of vehicle 1, such as accelerations of vehicle 1 in several directions, in particular the longitudinal and lateral acceleration of vehicle 1, and the command SPI is integrated into the behavioral control of vehicle 1. More precisely, the actuation state or actuation characteristic of an actuator that controls the output of machine 8, an actuator that performs a shift control of the transmission 13, an actuator that controls the operation of each shock absorber 4, an actuator that controls the operation of the steering device 15, and the like, are changed based on the longitudinal and lateral acceleration of vehicle 1 in order to modify the driving characteristics of vehicle 1.

[0129] Vehicle 1 is moving while experiencing not only longitudinal acceleration but also lateral acceleration and acceleration in a curve. Therefore, these multi-directional accelerations are incorporated into the preceding command SPI as vehicle parameters for Vehicle 1. This allows the command SPI to continue to adequately reflect the actual behavior of Vehicle 1. Consequently, it is possible to adjust the driving characteristics while still adequately incorporating the actual behavior of Vehicle 1.

[0130] Furthermore, in the control system according to the exemplary embodiment of the invention, when a command SPI is received based on the vehicle parameter of vehicle 1, such as the longitudinal and lateral acceleration of vehicle 1, fluctuation components of this longitudinal and lateral acceleration are mitigated. In particular, for example, a temporary or momentary large fluctuation component of an acceleration that occurs due to a rough driving operation by the driver, such as rapid acceleration, rapid braking, and rapid steering—that is, a high-frequency fluctuation component of an acceleration that becomes a disturbance variable—is removed by a low-pass filter.Additionally, a large, temporary or instantaneous fluctuation component of acceleration, which occurs due to a change in the condition of a road surface—such as when irregularities in the road surface increase or when the vehicle travels from a flat road to a hill with steep gradients—that is, when a fluctuation component of a specific frequency band becomes a disturbance, is removed by a low-pass filter and / or a high-pass filter. Therefore, it is possible to adequately suppress the influence of an acceleration fluctuation when determining a command SPI, even if the influence was not intended by the driver. As a consequence, the actual behavior of vehicle 1 can still be adequately included or considered in the command SPI.

[0131] It should be noted that in the embodiment of the invention, the command SPI is a parameter used when a so-called actuation property or driving property of the vehicle is changed. For example, the actuation property of the vehicle includes a control property, such as the control amount or control speed of an actuator (for example, a motor, a machine, a switching device, braking devices, and an electric power steering device) to an actuation component (for example, a steering system, an accelerator, and a brake). Additionally, the driving properties of the vehicle include the control property of an actuator (for example, an active stabilization device and an active suspension) of a section in conjunction with driving controlled on the basis of a predetermined command value. Furthermore, Fig.6 an example in which, when the command SPI is increased, the command SPI is quickly increased to a new maximum value of the instantaneous SPI; instead, the command SPI can be increased in a stepwise manner, or cautiously.

[0132] Additionally, the control system described above, according to the embodiment of the invention, can be implemented in combination with the prior art. For example, existing technologies, such as a neurocomputer or a neural network, shown in the system described in JP-A-06-249007, can be applied to the control technology according to the embodiment of the invention to implement the control system according to the embodiment of the invention.

Claims

[1] Vehicle control system which refers to an index that specifies a driving state of a vehicle (1) on the basis of a vehicle parameter that specifies a movement of the vehicle (1), and subsequently sets a driving characteristic of the vehicle (1) according to the index, with: a disturbance reduction unit that is set up to derive the index based on the vehicle parameter from which a fluctuation component, which fluctuates due to a condition of a road surface, is damped, characterized by , that The disturbance reduction unit is set up to attenuate a disturbance component of a predetermined frequency, which lies within a predetermined frequency band of the fluctuation component, by filtering the fluctuation component using a bandpass filter with a predetermined frequency property to suppress an influence of a disturbance of the fluctuation component on a resulting index. wherein the bandpass filter has a low-pass filter property that filters a differential value of the output value of a wheel speed sensor (19) and a high-pass filter property that filters an output value of a longitudinal acceleration sensor (25). [2] Vehicle control system according to claim 1, characterized by , that the vehicle parameter includes an acceleration of the vehicle (1). [3] Vehicle control system according to claim 1 or 2, characterized by , that the disturbance reduction unit is set up to attenuate a disturbance component of a predetermined frequency in the fluctuation component. [4] Vehicle control system according to claim 1, characterized by , that the filter used in the disturbance reduction unit is the same filter used in a unit different from the disturbance reduction unit. [5] Vehicle control system according to claim 1, characterized by, that the filter used in the disturbance reduction unit differs from a filter used in a unit that differs from the disturbance reduction unit. [6] Vehicle control system according to claim 1, characterized by , that in the filter used in the disturbance reduction unit, a filter property for a component in the longitudinal direction of the vehicle differs from a filter property for a component in a transverse direction of the vehicle. [7] Vehicle control system according to claim 1, characterized by , that the filter used in the disturbance reduction unit has a filter property that is varied according to a speed range of the vehicle.

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