JP2012071678A - Vehicle motion control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle motion control device that furthermore facilitates motion control suitable for a traveling state of a vehicle.SOLUTION: The vehicle motion control device 2 includes: a tire temperature acquisition unit 50 which acquires tire temperature of the vehicle 1; and a motion control unit 54 which controls the motion of the vehicle 1. The motion control unit 54 switches the motion control based on the tire temperature acquired in the tire temperature acquisition unit 50, and the motion control based on a prescribed value defined beforehand according to a traveling state of the vehicle 1. Thereby, when performing motion control based on the tire temperature, proper control can be performed by controlling based on the tire temperature which changes when traveling, and when the motion control is performed based on a prescribed value, shortening of operation time and reduction of load of an ECU40 can be performed. As a result, motion control suitable for traveling state of the vehicle 1 can be more easily performed.

Description

  The present invention relates to a vehicle motion control device.

  In recent vehicles, in order to make the motion characteristics during travel of the vehicle desired motion characteristics for the purpose of improving safety and the like, control for further assisting the driver's driving operation is performed. There is something to do. For example, in the vehicle motion control device described in Patent Document 1, a tire is photographed with a camera, the tire temperature and the actual rudder angle are detected from the photographed result, and the detected temperature and actual rudder angle are used to drive the vehicle. By reflecting on the control to be supported, the target control is approached more reliably.

JP 2006-142895 A

  When performing motion control suitable for the current running state of the vehicle when performing vehicle motion control, as in the vehicle motion control device described in Patent Document 1, while acquiring the current state of the vehicle By controlling, it is possible to perform control suitable for the current running state. However, when performing motion control while acquiring the current state of the vehicle in this way, for example, when detecting the tire temperature, the tire temperature is always detected, and the control amount based on the detected tire temperature is calculated. Therefore, since the motion control is performed, the control may be complicated. As described above, when the motion control of the vehicle is performed while acquiring the current state of the vehicle, the control suitable for the current traveling state of the vehicle can be performed, but the control may be complicated. Depending on the traveling state and the control state, it may take time for the control, or a large load may be applied to the traveling state detection means and the control amount calculation device.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle motion control device that can more easily perform motion control suitable for the traveling state of the vehicle.

  In order to solve the above-described problems and achieve the object, a vehicle motion control device according to the present invention includes a tire temperature acquisition unit that acquires a tire temperature of a vehicle, and a motion control unit that controls the motion of the vehicle. The motion control means switches between the motion control based on the tire temperature acquired by the tire temperature acquisition means and the motion control based on a predetermined value in accordance with a running state of the vehicle. It is characterized by.

  The vehicle motion control device further includes vehicle speed acquisition means for acquiring the vehicle speed of the vehicle and outside air temperature acquisition means for acquiring the outside air temperature of the vehicle, wherein the tire temperature acquisition means is the vehicle speed acquisition. Preferably, the tire temperature is acquired based on the vehicle speed acquired by the means and the outside air temperature acquired by the outside air temperature acquiring means.

  In the vehicle motion control device, it is preferable that the predetermined value is a predetermined tire temperature.

  In the vehicle motion control device, the predetermined value is preferably a value used when the motion control is performed based on the tire temperature in the case of a predetermined tire temperature.

  In the vehicle motion control apparatus, the motion control means performs the motion control based on the tire temperature acquired by the tire temperature acquisition means when the vehicle is in normal travel, and the vehicle is in normal travel. If not, it is preferable to perform the motion control by the predetermined value.

  In the vehicle motion control device, it is preferable that the traveling state is determined according to an acceleration generated in the vehicle when the vehicle is traveling.

  In the vehicle motion control device, the traveling state is preferably determined according to a frequency at which the acceleration having a predetermined magnitude occurs.

  In order to solve the above-described problems and achieve the object, a vehicle motion control device according to the present invention includes a tire temperature acquisition unit that acquires a tire temperature of a vehicle, and the motion of the vehicle based on the tire temperature. Motion control means for controlling the tire, wherein the motion control means switches the tire temperature used for motion control of the vehicle according to the running state of the vehicle.

  The vehicle motion control device according to the present invention switches between motion control performed based on the tire temperature acquired by the tire temperature acquisition means and motion control performed based on a predetermined value according to the traveling state of the vehicle. . Thereby, when exercise control is performed based on the tire temperature, appropriate control can be performed by performing control based on the tire temperature that changes during traveling, and when exercise control is performed based on a predetermined value. The calculation time can be shortened.

FIG. 1 is a schematic diagram of a vehicle including a vehicle motion control device according to an embodiment. FIG. 2 is a main part configuration diagram of the vehicle motion control device shown in FIG. 1. FIG. 3 is an explanatory diagram showing the relationship between tire temperature and cornering power. FIG. 4 is an explanatory diagram showing the relationship between tire temperature and self-aligning power. FIG. 5 is an explanatory diagram showing the relationship between tire characteristics and the degree of suppression of behavior change. FIG. 6 is an explanatory diagram of an EPS gain map. FIG. 7 is an explanatory diagram of the occurrence rate of lateral acceleration. FIG. 8 is an explanatory diagram of the occurrence rate of longitudinal acceleration. FIG. 9 is a flowchart illustrating an outline of a processing procedure of the vehicle motion control device according to the embodiment. FIG. 10 is a flowchart showing the processing procedure of the running state determination routine.

  Hereinafter, an embodiment of a vehicle motion control device according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

Embodiment
FIG. 1 is a schematic diagram of a vehicle including a vehicle motion control device according to an embodiment. The vehicle 1 including the vehicle motion control device 2 according to the embodiment is equipped with an engine 12 that is an internal combustion engine as a power source, and can run by the power of the engine 12. An automatic transmission 14 that is an example of a transmission is connected to the engine 12, and the power generated by the engine 12 can be transmitted to the automatic transmission 14. This automatic transmission 14 has a plurality of shift stages, and the power shifted by the automatic transmission 14 is provided on the left and right front wheels provided as drive wheels among the wheels 4 of the vehicle 1 via a power transmission path. 6 is transmitted as a driving force. Thereby, the vehicle 1 can run. Further, the automatic transmission 14 is provided with a vehicle speed sensor 16 that is a vehicle speed detecting means capable of detecting the vehicle speed by detecting the rotational speed of an output shaft (not shown) of the automatic transmission 14.

  Note that the vehicle 1 including the vehicle motion control device 2 according to the embodiment is a so-called front wheel drive vehicle in which the power generated by the engine 12 is transmitted to the front wheels 6 and the front wheels 6 generate driving force. 1 may be a drive type other than the front wheel drive, such as a rear wheel drive that generates a driving force at the rear wheel 8 or a four-wheel drive that generates a driving force at all the wheels 4. Further, a power source other than the internal combustion engine may be used, and an electric motor may be used as the power source, or both the engine 12 and the electric motor may be used.

  The front wheel 6 is provided as a driving wheel and at the same time as a steering wheel. Therefore, the front wheel 6 is provided so as to be steerable by a handle 20 used when a driver performs a driving operation. The handle 20 is connected to an EPS (Electric Power Steering) device 22 that is an electric power steering device, and the front wheel 6 can be steered via the EPS device 22.

  In addition, the vehicle 1 is provided with an outside air temperature sensor 30 that is an outside air temperature detecting unit that detects an outside air temperature that is a temperature outside the vehicle 1. In the outside air temperature sensor 30, at least a part of the detection portion communicates with or is exposed to the outside of the vehicle 1, and thereby the outside air temperature can be detected.

  Among these devices mounted on the vehicle 1, the engine 12, the automatic transmission 14, and the EPS device 22 are mounted on the vehicle 1 and an ECU (Electronic Control Unit) 40 that controls each part of the vehicle 1. And is controlled by the ECU 40 to operate. Further, the vehicle speed sensor 16 and the outside air temperature sensor 30 are connected to the ECU 40, and the vehicle speed sensor 16 and the outside air temperature sensor 30 detect the vehicle speed and the outside air temperature and transmit them to the ECU 40. The ECU 40 can transmit information and send / receive signals to / from each device and sensors connected to the ECU 40 in this way.

  FIG. 2 is a main part configuration diagram of the vehicle motion control device shown in FIG. 1. The ECU 40 includes a processing unit 42 having a CPU (Central Processing Unit) and the like, a storage unit 62 such as a RAM (Random Access Memory), and an input / output unit 64, which are connected to each other and transmit signals to each other. Delivery is possible. The engine 12, the automatic transmission 14, the vehicle speed sensor 16, the EPS device 22, the rudder angle sensor 24, and the outside air temperature sensor 30 connected to the ECU 40 are connected to the input / output unit 64. Signals are input / output to / from these engines 12 and the like. The storage unit 62 stores a computer program for controlling the vehicle motion control device 2.

  Further, the processing unit 42 of the ECU 40 provided in this manner includes a driving operation acquisition unit 44 that is a driving operation acquisition unit that acquires the state of the driving operation of the driver based on the detection result by the steering angle sensor 24, and the vehicle speed. A vehicle speed acquisition unit 46 that is a vehicle speed acquisition unit that acquires the vehicle speed during travel of the vehicle 1 based on the detection result of the sensor 16, and an outside air temperature acquisition unit that acquires the outside air temperature based on the detection result of the outside air temperature sensor 30. An outside air temperature acquisition unit 48, a tire temperature acquisition unit 50 that is a tire temperature acquisition unit for acquiring a tire temperature during traveling of the vehicle 1, and the power generated in the engine 12 are controlled or the automatic transmission 14 is shifted. A travel control unit 52 that is a travel control unit that performs travel control of the vehicle 1 by performing control, a motion control unit 54 that is a motion control unit that controls the motion of the vehicle 1, and a vehicle Has a traveling state determining section 56 is determined traveling state determining means running conditions of the.

  When the vehicle motion control device 2 is controlled by the ECU 40, for example, based on the detection result of the vehicle speed sensor 16 or the like, the processing unit 42 reads and calculates the computer program into a memory incorporated in the processing unit 42. Control is performed by operating the EPS device 22 or the like according to the result of the calculation. At that time, the processing unit 42 appropriately stores a numerical value in the middle of the calculation in the storage unit 62, and takes out the stored numerical value and executes the calculation.

  The vehicle motion control device 2 according to this embodiment is configured as described above, and the operation thereof will be described below. When the vehicle 1 travels, the driving operation state obtained by the driver operating the driving operation means such as an accelerator pedal is acquired by the driving operation acquisition unit 44, and the driving operation state acquired by the driving operation acquisition unit 44 is obtained. In response, the travel control unit 52 controls devices related to travel, such as the engine 12. Thereby, the vehicle 1 travels according to the driving operation of the driver.

  In addition, when there is an input for performing an exercise from the driver or an external input, the vehicle 1 performs an exercise according to the input. For example, when the driver operates the handle 20 when turning the vehicle 1, a steering torque that is a rotational torque when the handle 20 is steered is input to the EPS device 22, and the magnitude of the input steering torque is increased. Accordingly, a pressing force or a tensile force is output from the EPS device 22 to the front wheel 6. At that time, the EPS device 22 gives an assist torque to the steering torque and outputs the assist torque to the front wheels 6. As a result, the direction of the front wheel 6 changes at a steering angle corresponding to the operation of the steering wheel 20, and a lateral force is generated on the front wheel 6. Accordingly, the direction of the front wheel 6 changes and the traveling direction of the entire vehicle 1 changes, so that the vehicle 1 turns.

  In addition, the vehicle 1 is capable of motion control for the purpose of improving safety when the vehicle 1 is traveling, and bringing the motion characteristics of the vehicle 1 closer to the driver's feeling. Specifically, when the driver operates the steering wheel 20, the EPS device 22 applies assist torque to the steering torque to change the direction of the front wheels 6. The assist torque is changed according to the above. Thereby, the driving characteristic with respect to the driving operation by the driver is changed according to the traveling state of the vehicle 1.

  When the vehicle 1 travels, it is provided so that the motion control can be performed by changing the driving characteristics in accordance with the travel state as described above. The travel state of the vehicle 1 used in this case includes wheels The tire temperature which is the temperature of the tire 10 included in the tire 4 is used. That is, in the vehicle motion control device 2 according to the present embodiment, the motion characteristic with respect to the driving operation is changed based on the tire temperature, and the motion control during the traveling of the vehicle 1 is performed.

  Here, the relationship between tire temperature and motion characteristics will be described. When the vehicle 1 travels, the tire 10 of the wheel 4 generates various forces, and the vehicle 1 travels with motion characteristics based on these forces. The vehicle 1 thus travels with a motion characteristic based on the force generated by the tire 10, but the characteristic of the force generated by the tire 10 is highly temperature dependent and changes according to the temperature of the tire 10.

  Thus, as the force that occurs in the tire 10 and affects the motion characteristics when the vehicle 1 travels, cornering power and self-aligning power can be cited. Of these, the cornering power is a force corresponding to the cornering force CF per unit slip angle (side slip angle) β shown in FIG. The slip angle β is an angle formed by the traveling direction of the tire 10 and the tire center plane. The cornering force CF is a component force applied in a direction perpendicular to the traveling direction of the tire 10 when the vehicle 1 is cornered. Yes. That is, the cornering power (CP) is a force in a direction orthogonal to the rotation direction of the wheel 4, that is, a lateral force generated in the tire 10.

  Further, the self-aligning power is a force corresponding to the self-aligning torque SAT per unit slip angle β shown in FIG. The self-aligning torque SAT is a moment generated around the ground contact point (around the vertical axis) of the tire 10, and the front wheel 6 moves straight when the direction of the front wheel 6 is changed with respect to the straight traveling direction of the vehicle 1. It is a restoring force that tries to return to the direction of the direction. In other words, when the tire 10 rolls with a predetermined slip angle β, the force of the cornering force CF deviates from the ground contact center point of the tire 10, so that the slip angle β is reduced around the ground contact center. Force (torque) works in the direction. This force is the self-aligning torque SAT, and the self-aligning torque SAT is a force that affects the straight running stability of the vehicle 1 and the weight of the steering wheel 20 during steering. That is, the self-aligning power (SAP) is a force generated in the tire 10 such that the direction of the wheel 4 is in the direction along the rotation direction with respect to the moving direction of the wheel 4. The straight running stability and the weight during steering change depending on the force generated in the vehicle.

  FIG. 3 is an explanatory diagram showing the relationship between tire temperature and cornering power. FIG. 4 is an explanatory diagram showing the relationship between tire temperature and self-aligning power. The tire 10 is configured such that a tread rubber is disposed on the outer peripheral portion, but the tread rubber changes its state depending on the temperature, and becomes soft and easily deforms as the tire temperature increases. For this reason, when the vertical load is the same, the characteristics of CP and SAP change depending on the tire temperature. For example, CP increases as the tire temperature decreases, as shown in FIG. Decreases as the value increases. Similarly, as shown in FIG. 4, the SAP increases as the tire temperature decreases, and conversely decreases as the tire temperature increases.

  The CP and SAP change with the tire temperature as described above. However, when the CP and SAP change, the driving feeling of the driver when the vehicle 1 travels may also change. For this reason, for example, when the tire 10 is cold at the beginning of traveling of the vehicle 1 and when the temperature of the tire 10 rises after a predetermined time has elapsed after the start of traveling, the CP and SAP change and driving The driver's driving sensation may be different. Specifically, as the temperature of the tire 10 increases and the CP and SAP decrease, the behavior of the vehicle 1 changes with respect to the operating force of the driving operation by the driver and the disturbance input when the vehicle 1 travels. It becomes easy.

  For this reason, in the vehicle motion control device 2 according to the present embodiment, as the temperature of the tire 10 becomes relatively high, the behavior change of the vehicle 1 with respect to an input such as an operating force or a disturbance is suppressed, or the temperature of the tire 10 As the engine speed becomes relatively low, the behavior change of the vehicle 1 with respect to the input of the operating force or disturbance is allowed, and the behavior of the vehicle 1 with respect to the input of the operating force is made as constant as possible regardless of the tire temperature. That is, the change amount of the behavior change with respect to the input to the vehicle 1 is made constant regardless of the tire temperature.

  FIG. 5 is an explanatory diagram showing the relationship between tire characteristics and the degree of suppression of behavior change. A method for making the change amount of the behavior change with respect to the input to the vehicle 1 constant regardless of the tire temperature will be described. The behavior change during the traveling of the vehicle 1 can be arbitrarily controlled. Change according to temperature. Specifically, the behavior change with respect to the input to the vehicle 1 can be suppressed, and the suppression degree L1 of the behavior change is increased as the tire temperature increases as shown in FIG. As a result, a decrease in CP, SAP, or the like that decreases as the tire temperature increases is compensated by changing the motion characteristics of the vehicle 1.

  FIG. 6 is an explanatory diagram of an EPS gain map. When the change amount of the behavior change with respect to the input to the vehicle 1 is made constant regardless of the tire temperature, the motion characteristic of the vehicle 1 is changed in accordance with the tire temperature in this way. This is performed by changing the assist torque generated in the EPS device 22 by the motion control unit 54 of the processing unit 42 of the ECU 40. In other words, the EPS device 22 attempts to reduce the steering force when steering the front wheel 6 by applying the assist torque to the steering torque input to the handle 20 and changing the direction of the front wheel 6. When changing the characteristics, the assist torque is changed according to the tire temperature. Thereby, the actual steering amount with respect to the steering force is changed, and the motion characteristics when the vehicle 1 is traveling are changed.

  As described above, when the assist torque of the EPS device 22 is changed according to the tire temperature, for example, the EPS gain that is a gain when the EPS device 22 is controlled is changed according to the tire temperature. Specifically, the EPS gain, which is a gain at the time of output from the EPS device 22 with respect to the input to the EPS device 22, is adjusted by the motion control unit 54 to decrease as the tire temperature increases, so that the tire temperature is increased. Increase as it gets lower. Thereby, the assist torque of the EPS device 22 is reduced as the tire temperature increases, and the assist torque is increased as the tire temperature decreases.

  In other words, the tire characteristics CP and SAP decrease as the tire temperature increases, so the reaction force when the driver steers, that is, the reaction force against the steering torque also decreases as the tire temperature increases. For this reason, when the tire temperature is high, it is possible to steer even if the force at the time of operation is small compared to the case where the tire temperature is low. As a result, if the assist torque when the tire temperature is high is made the same as the assist torque when the tire temperature is low, the sum of the driver's steering torque and assist torque with respect to the force required for steering The value tends to be excessively large as compared with the case where the tire temperature is low. In this case, the direction of the front wheel 6 may be changed more than necessary, and the behavior of the vehicle 1 may become too large. Therefore, by reducing the EPS gain by the motion control unit 54 so that the assist torque of the EPS device 22 decreases as the tire temperature increases, the behavior of the vehicle 1 is suppressed from becoming too large.

  On the other hand, CP and SAP increase when the tire temperature decreases, so the reaction force against the steering torque also increases as the tire temperature decreases. For this reason, when the tire temperature is low, it is necessary to increase the force at the time of operation as compared with the case where the tire temperature is high. Therefore, by increasing the EPS gain by the motion control unit 54 so that the assist torque of the EPS device 22 increases as the tire temperature decreases, the amount of behavior with respect to the driving operation of the vehicle 1 is ensured. Thereby, the change amount of the behavior change with respect to the input to the vehicle 1 can be made the same regardless of the tire temperature.

  When motion control of the vehicle 1 is performed, the amount of change in behavior during traveling is adjusted by changing the motion characteristics of the vehicle 1 in accordance with the tire temperature as described above. The tire temperature used for this control is: In the vehicle motion control device 2 according to the embodiment, the estimation is based on the vehicle speed and the outside air temperature. Among these, the vehicle speed is acquired by the vehicle speed acquisition unit 46 included in the processing unit 42 of the ECU 40 based on the detection result of the vehicle speed sensor 16, and the outside air temperature is included in the processing unit 42 of the ECU 40 based on the detection result of the outside air temperature sensor 30. Obtained by the outside air temperature obtaining unit 48. The tire temperature is acquired by estimating the tire temperature by the tire temperature acquisition unit 50 included in the processing unit 42 of the ECU 40 based on the vehicle speed and the outside air temperature acquired as described above.

  FIG. 7 is an explanatory diagram of the occurrence rate of lateral acceleration. FIG. 8 is an explanatory diagram of the occurrence rate of longitudinal acceleration. FIG. 7 and FIG. 8 illustrate the degree of occurrence of acceleration during general traveling of the vehicle 1. Here, a tire temperature estimation method will be described. The tire 10 when the vehicle 1 travels generates heat due to energy input from the outside when the vehicle 1 travels. However, the energy input to the tire 10 when the vehicle 1 travels is (Qin = rolling resistance component). Energy + braking drive energy + cornering energy).

Further, in general traveling when the vehicle 1 is traveling, as shown in FIG. 7, about 60% of the traveling time is 0.1 G or less in lateral acceleration, and as shown in FIGS. 90% is 0.4 G or less in both lateral acceleration and longitudinal acceleration. As described above, in general traveling, the vehicle often travels with a small lateral acceleration and longitudinal acceleration in the majority of traveling, and therefore cornering, which is energy generated in the tire 10 when lateral acceleration occurs. The energy for braking and driving, which is the energy generated in the tire 10 when the longitudinal acceleration is generated, can be ignored in general traveling. For this reason, the energy Qin input to the tire 10 is ignored when the cornering energy and the braking / driving energy are ignored, the rolling resistance of the tire is RR, the vehicle speed is V, and the coefficient determined by the tire 10 is set to a. Can be expressed by the following formula (1).
Qin = α · RR · d = α · RR · Δt · V = aV (1)

Further, when the tire temperature Ttire when estimating the temperature of the tire 10 based on the formula (1) is expressed by the formula, when the outside air temperature is Tair and the coefficients b and c determined by the tire 10 are set, the following It can be expressed as equation (2).
Ttire = a · V + b · (Ttire−Tair) + Ttire + c (2)

  Of the coefficients used in the formulas (1) and (2), a is a coefficient related to heat generation of the tire 10 and varies depending on the physical properties of the rubber constituting the tire 10. The coefficient a becomes smaller when rubber having a small hysteresis loss is used. Further, b is a coefficient related to heat dissipation of the tire 10 and varies depending on the size of the tire 10. For example, in the case of the tire 10 having a large size, since the surface area becomes large, it is easy to radiate heat. Such a heat radiating characteristic is represented by a coefficient b. In addition, c is a value that varies depending on the traveling state of the vehicle 1 such as the amount of heat generated by the tire 10 when the steering wheel 20 is steered or the amount of heat generated by applying a brake by a braking device (not shown). Yes. These coefficients a, b, and c are all set as values other than zero.

  When the vehicle 1 travels, the tire temperature acquisition unit 50 uses the equation (2) to calculate the tire temperature Ttire based on the vehicle speed V acquired by the vehicle speed acquisition unit 46 and the outside air temperature Tair acquired by the outside air temperature acquisition unit 48. Estimate and get.

  The tire temperature can be estimated based on the vehicle speed and the outside air temperature as described above, but the tire characteristics that change depending on the tire temperature are such that the CP and the SAP become smaller as the temperature becomes higher as shown in FIGS. It has become. Further, in this tire characteristic, when the tire temperature exceeds a predetermined temperature, changes in CP and SAP with respect to the tire temperature become small.

  On the other hand, since the motion control of the vehicle 1 is performed while estimating the tire temperature, many processes such as calculation are performed at the time of control, and the burden on the ECU 40 is increased. Is higher, the change with respect to the change in the tire temperature is reduced. For this reason, in the vehicle motion control device 2 according to the present embodiment, when the tire temperature is higher than a predetermined temperature, the tire temperature is not estimated, and the motion control is performed assuming that the tire temperature is a preset temperature. Do.

  Such a running state in which the tire temperature becomes high includes a running state in the case where the lateral acceleration and the longitudinal acceleration are large. That is, when the lateral acceleration or the longitudinal acceleration is large, the cornering energy or the braking / driving energy input to the tire 10 is increased, so that the tire temperature is likely to be increased. When is high, motion control is performed without estimating the tire temperature.

  Here, the situation where the lateral acceleration and the longitudinal acceleration tend to be large will be described. In general traveling, as shown in FIGS. 7 and 8, the lateral acceleration and the longitudinal acceleration are about 90% of the traveling time. The frequency at which the lateral acceleration or the longitudinal acceleration becomes 0.4 G or more is about 10% or less of the running time. For this reason, inferring from the state of acceleration during such general traveling, when the frequency at which the lateral acceleration or the longitudinal acceleration is 0.4 G or more is 10% or more with respect to the traveling time, It is possible to determine that the tire temperature is likely to increase due to a large lateral acceleration or longitudinal acceleration, which is a special traveling different from the traveling.

  Therefore, when the frequency at which the lateral acceleration or the longitudinal acceleration is 0.4 G or more is 10% or more with respect to the running time, it is assumed that a special running that is not a normal normal running, for example, a sports running is performed. Determine and exercise control without estimating tire temperature. That is, the traveling state of the vehicle 1 is determined according to the acceleration generated in the vehicle 1 when the vehicle 1 is traveling. Specifically, the traveling state is determined according to the frequency with which a predetermined magnitude of acceleration is generated, If it is determined, motion control is performed without estimating the tire temperature. In this case, the exercise control is performed on the assumption that the tire temperature is a preset temperature, and the temperature set in this way is CP with respect to a change in the tire temperature, as indicated by Tconst in FIGS. And the boundary temperature at which it can be determined that the change in SAP is small.

  That is, when it is determined that the vehicle 1 is traveling in sport, the tire temperature is not estimated by the tire temperature acquisition unit 50, and the tire temperature is assumed to be the set value Tconst, and the motion control is performed. The EPS device 22 is controlled by the unit 54 so that the motion characteristic is a motion characteristic suitable for the case where the tire temperature is Tconst. In this way, the motion control unit 54 switches between motion control based on the tire temperature acquired by the tire temperature acquisition unit 50 and motion control based on a predetermined value according to the traveling state of the vehicle 1. Take control.

  FIG. 9 is a flowchart illustrating an outline of a processing procedure of the vehicle motion control device according to the embodiment. Next, the outline of the control method of the vehicle motion control device 2 according to the present embodiment, that is, the processing procedure of the vehicle motion control device 2 will be described. Note that the following processing is a processing procedure when the motion characteristics of the vehicle 1 are set based on the tire temperature and the motion control of the vehicle 1 is performed. Called and executed every period.

In the processing procedure of the vehicle motion control device 2 according to the present embodiment, first, the vehicle speed V _i and the outside air temperature Tair _i are acquired (step ST101). Note that i used here indicates a counter at the time of control, and is stored in the storage unit 62 of the ECU 40. As for i, i = 0 is calculated when the main switch of the vehicle 1 is turned on or when the motion control by the vehicle motion control device 2 is started, and 0 is put into i. Further, the vehicle speed V _i indicates the vehicle speed V at the time of the counter i that increases as the process of motion control is repeated. Similarly, the outside air temperature Tair _i indicates the outside air temperature Tair at the time of the counter i. The vehicle speed V _i and the outside air temperature Tair _i are obtained by obtaining the vehicle speed V _i from the detection result of the vehicle speed sensor 16 by the vehicle speed obtaining unit 46, and the outside air temperature Tair _i obtaining the detection result of the outside air temperature sensor 30. This is performed by obtaining the data in the part 48.

Next, it is determined whether i ≠ 0 (step ST102). This determination is performed by the motion control unit 54 and it is determined whether i stored in the storage unit 62 is zero. If it is determined by this determination that i is not 0, that is, if i = 0 is determined (No determination in step ST102), tire temperature Ttire _i = outside temperature Tair _i is set (step ST102). ST103). That is, in the case of i = 0, the temperature of the tire 10 is the vehicle 1 because it is immediately after the main switch of the vehicle 1 is turned on or immediately after the start of the motion control by the vehicle motion control device 2. It can be estimated that the energy generated during the traveling of the vehicle has not increased. Therefore, in this case, it is determined that the tire temperature is about the same as the current outside air temperature, and the tire temperature acquisition unit 50 calculates the tire temperature Ttire _i = the outside air temperature Tair _i to the tire temperature Ttire _i. Substitute the value of Tair _i .

  On the other hand, if it is determined that i ≠ 0 (step ST102, Yes determination), it is next determined whether or not the parking is for a long time (step ST104). This determination is performed by the motion control unit 54. Based on the vehicle speed acquired by the vehicle speed acquisition unit 46, the motion control unit 54 determines whether or not the time from when the vehicle speed reaches 0 km / h is a long time. The time used for this determination is set in advance as a threshold of time that can be determined that the temperature of the tire 10 is approximately equal to the outside air temperature by stopping the vehicle 1 for a long time after stopping the vehicle 1. And stored in the storage unit 62. The motion control unit 54 determines whether or not the time after the vehicle speed becomes 0 km / h is equal to or longer than the threshold time stored in the storage unit 62 in this manner. It is determined whether or not there is.

If it is determined by this determination that the vehicle is parked for a long time (step ST104, Yes determination), the tire temperature is determined to be approximately the same as the current outside air temperature, and the tire temperature acquisition unit 50 determines the tire temperature Ttire _i. = Calculate the outside air temperature Tair _i (step ST103). Thereby, the value of the outside air temperature Tair _i is substituted for the tire temperature Ttire _i .

  On the other hand, when it is determined that the parking is not a long time (step ST104, No determination), a running state determination routine is executed (step ST105).

  FIG. 10 is a flowchart showing the processing procedure of the running state determination routine. When the running state determination routine is executed, the running state determination routine stored in the storage unit 62 is called and executed. In this running state determination routine, first, lateral acceleration and longitudinal acceleration are acquired (step ST201). The lateral acceleration and the longitudinal acceleration are detected by an acceleration sensor (not shown) that is mounted on the vehicle 1 and detects the acceleration generated in the vehicle 1, and the detection result is acquired by the traveling state determination unit 56.

  Note that these lateral acceleration and longitudinal acceleration may be obtained by other than detecting with an acceleration sensor. For example, the longitudinal acceleration is estimated based on the operating state of the engine 12, the speed selected by the automatic transmission 14, or the vehicle speed detected by the vehicle speed sensor 16, or decreased based on the operating state of the braking device. You may acquire by estimating speed. Further, the lateral acceleration may be obtained by estimating based on the vehicle speed detected by the vehicle speed sensor 16 and the steering angle detected by the steering angle sensor 24.

  Next, the acceleration occurrence frequency is calculated (step ST202). In this calculation, the running state determination unit 56 continuously acquires lateral acceleration and longitudinal acceleration, and calculates the frequency of occurrence for each magnitude of acceleration as illustrated in FIGS. 7 and 8.

  Next, it is determined whether or not 0.4G frequency> 10% (step ST203). That is, whether or not the time when the longitudinal acceleration or the lateral acceleration is 0.4 G or more with respect to the traveling time of the vehicle 1 exceeds 10% is determined by the acceleration occurrence frequency calculated by the traveling state determination unit 56. Based on this, the traveling state determination unit 56 makes the determination.

  When it is determined by this determination that 0.4G frequency> 10% (step ST203, Yes determination), it is determined that the sport running (step ST204). That is, when performing sport running, the longitudinal acceleration and the lateral acceleration increase in value, and the frequency of increasing the value increases. For this reason, when it is determined that the time during which the longitudinal acceleration or the lateral acceleration is 0.4 G or more exceeds 10%, and it is determined that the vehicle is traveling in a state in which a large acceleration is likely to occur, It is determined that the sport is running.

  On the other hand, when it is determined that 0.4G frequency> 10% is not satisfied (step ST203, No determination), it is determined that the vehicle is traveling normally (step ST205). In other words, during normal driving, the longitudinal acceleration and lateral acceleration are unlikely to increase in value, so it is determined that the time during which the longitudinal acceleration and lateral acceleration are 0.4 G or more is 10% or less, and a large acceleration is generated. If it is determined that the vehicle is traveling in a state where it is not, it is determined that the vehicle is traveling normally.

  As described above, when the traveling state of the vehicle 1 is determined based on the acceleration, the vehicle exits from the traveling state determination routine and returns to the original processing procedure of the motion control. After returning to the original processing procedure, it is next determined whether or not it is a sport run (step ST106). In this determination, it is determined whether or not the traveling state of the vehicle 1 determined in the traveling state determination routine is a sport traveling.

If it is determined by this determination that the traveling state of the vehicle 1 is normal traveling (No determination in step ST106), {tire temperature Ttire _i = a · V _i + b · (Ttire _i-1 −Tair _{i− 1} ) Calculate + Ttire _i-1 + c} (step ST107). That is, when it is determined that the vehicle 1 is traveling normally, the tire temperature acquisition unit 50 acquires the vehicle speed V _i acquired by the vehicle speed acquisition unit 46 and the outside air temperature Tair _i acquired by the outside air temperature acquisition unit 48. Based on the above, the tire temperature Ttire _i is calculated using the above-described equation (2). Here, Ttire _i-1 and Tair _i-1 used for this calculation are the tire temperature and the outside air temperature acquired when the processing procedure of the motion control is called last time and a series of processing is performed. The tire temperature acquisition unit 50 thus estimates the tire temperature by calculating using the vehicle speed and the outside air temperature, and acquires the current tire temperature.

On the other hand, if it is determined that the vehicle 1 is in a sporting state by determining whether or not it is a sporting driving (step ST106, Yes determination), the tire temperature Ttire _i = the set tire temperature Tconst. (Step ST108). That is, when it is determined that the vehicle 1 is performing sport running, the tire temperature acquisition unit 50 calculates tire temperature Ttire _i = set tire temperature Tconst. The set tire temperature Tconst is set in advance as a temperature at which the change in CP and SAP becomes small (see FIGS. 3 and 4) and is stored in the storage unit 62. By performing this calculation, the tire temperature acquisition unit 50 substitutes the value of the set tire temperature Tconst into the tire temperature Ttire _i .

As described above, when the tire temperature Ttire _i is calculated by calculating {Ttire _i = a · V _i + b · (Ttire _i−1 −Tair _i−1 ) + Ttire _i−1 + c} (step ST107), _or, if the calculated tire temperature Ttire _i by calculating the Ttire i = Tconst (step ST 108), _or, in the case of calculating the tire temperature Ttire _i by calculating the Ttire _i = Tair i (step ST 103) Next, motion control is performed based on the tire temperature Ttire _i (step ST109). This motion control is performed by the motion control unit 54. The motion control unit 54 performs motion control by controlling the EPS device 22 based on the tire temperature Ttire _i and the gain map of the EPS device 22 stored in the storage unit 62.

Specifically, the gain map of the EPS device 22 used when performing motion control in this way is a map showing the relationship between tire temperature and EPS gain, as shown in FIG. The EPS gain at the current tire temperature is derived by comparing the calculated tire temperature Ttire _i with this gain map. The motion control unit 54 controls the EPS device 22 using the EPS gain, thereby adjusting the assist torque generated in the EPS device 22 when the driver operates the steering wheel 20 according to the tire temperature. That is, the motion control unit 54 performs motion control by changing motion characteristics according to the tire temperature.

Thus, if motion control is performed based on the tire temperature Ttire _i , then i = i + 1 is calculated (step ST110). That is, by adding a value of i + 1 to i stored in the storage unit 62, 1 is added to i. When i = i + 1 is calculated in this way, the processing procedure is exited.

  In the vehicle motion control device 2 described above, the motion control unit 54 that controls the motion of the vehicle 1 based on the tire temperature switches the tire temperature used for motion control of the vehicle 1 according to the traveling state of the vehicle 1. Thereby, the motion control of the vehicle 1 is not performed by a uniform method, and the motion control can be performed by simple control depending on the traveling state of the vehicle 1. Thereby, the motion control suitable for the traveling state of the vehicle 1 can be performed more easily.

  Specifically, the exercise control is switched according to the traveling state of the vehicle 1, and exercise control performed based on the tire temperature acquired by the tire temperature acquisition unit 50 and exercise control performed based on a predetermined value set in advance. Are switched according to the traveling state of the vehicle 1. Thereby, when exercise control is performed based on the tire temperature, appropriate control can be performed by performing control based on the tire temperature that changes during traveling, and when exercise control is performed based on a predetermined value. The calculation time can be shortened and the load on the ECU 40 can be reduced. As a result, motion control suitable for the traveling state of the vehicle 1 can be performed more easily.

  Further, the motion control unit 54 performs motion control based on the tire temperature acquired by the tire temperature acquisition unit 50 during normal traveling of the vehicle 1, and a preset tire temperature set as a predetermined value during sports traveling of the vehicle 1. Motion control is performed based on Tconst. As a result, during normal travel in which the motion characteristics are likely to change due to changes in tire temperature, appropriate control can be performed by performing motion control based on the tire temperature. Further, during sports running in which exercise characteristics are difficult to change due to changes in tire temperature, exercise control is performed based on a predetermined value, so that the calculation time can be shortened and the load on the ECU 40 can be reduced. As a result, motion control suitable for the traveling state of the vehicle 1 can be performed more easily.

  The tire temperature acquisition unit 50 estimates the tire temperature based on the vehicle speed acquired by the vehicle speed acquisition unit 46 and the outside air temperature acquired by the outside air temperature acquisition unit 48, and acquires the current tire temperature. Therefore, the temperature of the tire 10 can be acquired without providing sensors for detecting the temperature of the tire 10. Thereby, when controlling the motion of the vehicle 1 based on the tire temperature, it can be easily performed, and the manufacturing cost can be reduced. That is, when the vehicle 1 travels, the tire 10 rotates, so it is difficult to provide sensors for detecting the temperature on the rotating tire 10 in this way, which easily leads to an increase in manufacturing cost. Become. On the other hand, in the vehicle motion control device 2 according to the embodiment, the tire temperature is acquired based on the vehicle speed and the outside air temperature, and therefore the tire temperature can be easily acquired. As a result, motion control suitable for the traveling state of the vehicle 1 can be more easily performed while suppressing an increase in manufacturing cost.

  Further, the predetermined value used for the exercise control when it is determined that the sport running is performed is a set tire temperature Tconst which is a predetermined tire temperature. For this reason, when it is determined that the vehicle 1 is performing sports travel when performing motion control of the vehicle 1, the calculation time can be shortened or the ECU 40 can be controlled by performing control based on the set tire temperature Tconst. Control suitable for the traveling state of the vehicle 1 can be performed while reducing the load of the vehicle. As a result, motion control suitable for the traveling state of the vehicle 1 can be performed more easily.

  Further, since the traveling state of the vehicle 1 that is a reference for switching the motion control is determined according to the acceleration generated in the vehicle 1 when the vehicle 1 is traveling, the traveling state of the vehicle 1 that affects the tire temperature is more appropriately determined. can do. As a result, the motion control suitable for the traveling state of the vehicle 1 can be performed more reliably.

  Further, since the traveling state of the vehicle 1 is further determined according to the frequency at which a predetermined magnitude of acceleration occurs, the traveling state of the vehicle 1 can be determined based on the acceleration over a predetermined traveling time. The traveling state of 1 can be accurately determined. As a result, the motion control suitable for the traveling state of the vehicle 1 can be performed more reliably.

  In the vehicle motion control device 2 according to the embodiment, a set tire temperature Tconst that is a preset tire temperature is used as a predetermined value used when performing motion control during sports running of the vehicle 1, and this setting is performed. Although exercise control is performed based on the tire temperature Tconst, the predetermined value used for exercise control during sports running may be other than the set tire temperature Tconst. For example, a value used when exercise control is performed based on the tire temperature in the case of a predetermined tire temperature may be used as the predetermined value used when exercise control during sport running is performed. That is, the case where the exercise control is performed by the EPS device 22 will be described. An EPS gain in the case of a predetermined tire temperature is set in advance as in the set tire temperature Tconst, and the set EPS gain is set during sports running. It may be used as a predetermined value used when performing motion control.

  As described above, when the predetermined value of the EPS gain is set, when it is determined that the vehicle 1 is performing sport running, the EPS device 22 is controlled by the set value of the EPS gain. Change motion characteristics to characteristics suitable for sports driving. As a result, when it is determined that the sport running is performed, the EPS device 22 can be directly controlled by the set value of the EPS gain without deriving the EPS gain based on the tire temperature. Can be omitted. Therefore, the calculation time can be shortened and the load on the ECU 40 can be reduced more reliably. As a result, motion control suitable for the traveling state of the vehicle 1 can be performed more reliably and easily.

  In the vehicle motion control device 2 according to the embodiment, the motion control of the vehicle 1 is performed by controlling the EPS device 22, but the motion control of the vehicle 1 is performed using a device other than the EPS device 22. May be. For example, when an ARS (Active Rear Steering) device that is an active rear wheel steering device that steers the rear wheel 8 according to the traveling state of the vehicle 1 is provided, the vehicle is operated by steering the rear wheel 8 with the ARS device. One motion control may be performed. In this case, the control amount at the time of steering the rear wheel 8 is changed based on the tire temperature during normal traveling, and the control amount based on the predetermined tire temperature or the predetermined control amount during sports traveling. By controlling, the motion control of the vehicle 1 is switched.

  In addition, when a VSC (Vehicle Stability Control) device that is a behavior stabilization device that stabilizes the behavior by controlling the driving force and the braking force according to the traveling state of the vehicle 1 is provided, the driving is performed by the VSC device. The motion control of the vehicle 1 may be performed by controlling the force and the braking force. In this case, the control amount of the driving force and the braking force is changed based on the tire temperature during normal traveling, and is controlled with a control amount based on a predetermined tire temperature or a predetermined control amount during sports traveling. Thus, the motion control of the vehicle 1 is switched.

  Further, when the suspension device of the wheel 4 is provided with an adaptive variable suspension system (AVS) device that is a damping force variable device capable of adjusting a damping force when the wheel 4 is stroked by the suspension device, the suspension is attenuated by the AVS device. The motion control of the vehicle 1 may be performed by adjusting the force. In this case, the control amount of the damping force is changed based on the tire temperature during normal running, and is controlled with a control amount based on a predetermined tire temperature during sports running or a predetermined control amount, The motion control of the vehicle 1 is switched.

  As described above, the apparatus in the case of performing the motion control of the vehicle 1 can change the control amount of the apparatus based on the tire temperature, and can perform the motion control by changing the control amount in this way. If it is an apparatus, the kind of apparatus and the method of control are not ask | required.

  Further, in the vehicle motion control device 2 according to the embodiment, the tire temperature is obtained by estimation based on the vehicle speed and the outside air temperature, but the tire temperature may be obtained by a method other than this. For example, the tire temperature may be estimated based on other than the vehicle speed and the outside air temperature, or a detection means such as a sensor for detecting the tire temperature is provided, and the tire temperature is obtained by detecting with such a detection means. May be. The method of acquiring the tire temperature is not limited as long as the method can acquire the temperature that changes when the vehicle 1 travels as appropriate.

  In the vehicle motion control device 2 according to the embodiment, when it is determined whether or not the traveling state of the vehicle 1 is sports traveling, the time during which the longitudinal acceleration and the lateral acceleration are 0.4 G or more is 10%. However, the determination may be made based on other determination criteria. That is, if the traveling state of the vehicle 1 is a criterion in which the tire temperature is a traveling state in which the tire temperature is in a temperature range in which the change in tire characteristics such as CP and SAP becomes small with respect to the change in the tire temperature, the determination criterion. The judgment method is not questioned.

  For example, when a determination method different from the above-described determination method is illustrated, the output characteristics of the engine 12 and the damping force characteristics of the suspension device can be switched to a plurality of modes, and the vehicle 1 having a mode suitable for sports driving can be switched. In this case, the traveling state of the vehicle 1 may be determined based on the selected mode. That is, in this case, when a mode suitable for sports driving is selected, it may be determined that the driving state of the vehicle 1 is sports driving.

  As described above, the vehicle motion control device according to the present invention is useful for a vehicle that performs motion control during traveling of the vehicle, and is particularly suitable for performing motion control according to tire temperature.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Vehicle motion control apparatus 4 Wheel 10 Tire 16 Vehicle speed sensor 22 EPS apparatus 30 Outside temperature sensor 40 ECU
44 driving operation acquisition unit 46 vehicle speed acquisition unit 48 outside air temperature acquisition unit 50 tire temperature acquisition unit 52 travel control unit 54 motion control unit 56 travel state determination unit

Claims (8)

Tire temperature acquisition means for acquiring the tire temperature of the vehicle;
Motion control means for controlling the motion of the vehicle;
With
The motion control means switches between the motion control based on the tire temperature acquired by the tire temperature acquisition means and the motion control based on a predetermined value in accordance with a running state of the vehicle. A vehicle motion control device. Vehicle speed acquisition means for acquiring the vehicle speed of the vehicle;
Outside temperature acquisition means for acquiring the outside temperature of the vehicle;
With
The tire temperature acquisition unit acquires the tire temperature based on the vehicle speed acquired by the vehicle speed acquisition unit and the outside air temperature acquired by the outside air temperature acquisition unit. Vehicle motion control device.   The vehicle motion control device according to claim 1, wherein the predetermined value is a predetermined tire temperature.   The vehicle motion control device according to claim 1, wherein the predetermined value is a value used when the motion control is performed based on the tire temperature in the case of a predetermined tire temperature.   The movement control means performs the movement control based on the tire temperature acquired by the tire temperature acquisition means when the vehicle is running normally, and when the vehicle is not running normally, the movement control means performs the movement control according to the predetermined value. The vehicle motion control device according to claim 1, wherein motion control is performed.   The vehicle movement control device according to claim 1, wherein the traveling state is determined according to an acceleration generated in the vehicle when the vehicle is traveling.   The vehicle movement control device according to claim 6, wherein the running state is determined according to a frequency at which the acceleration having a predetermined magnitude occurs. Tire temperature acquisition means for acquiring the tire temperature of the vehicle;
Motion control means for controlling the motion of the vehicle based on the tire temperature;
With
The vehicle motion control device, wherein the motion control means switches the tire temperature used for motion control of the vehicle according to a running state of the vehicle.

Images