JP2022064472A - Index calculation system and program - Google Patents

Abstract

To provide a system and a program which can provide an index for evaluating the responses (side slip and yaw motion) at the extremely early stage of the minute steering of a vehicle.SOLUTION: An index calculation system for calculating an index for evaluating the responses at the extremely early stage of the steering of a vehicle comprises: input reception means which receives at least the inputs of a mass m of the vehicle, load distributions (Wf:Wr) of front and rear wheels of the vehicle and a distance I between a shaft of the front wheel and a shaft of the rear wheel of the vehicle; and computing means which calculates a value equivalent to the yawing inertial moment around the center of percussion to the lateral force acting on the front wheel at the extremely early stage of the steering of the vehicle as an index on the basis of the input mass m, load distributions (Wf:Wr) and distance I.SELECTED DRAWING: Figure 10

Description

The present invention relates to a system and a program for calculating an index for evaluating the response at the initial stage of steering of a vehicle.

The driver who drives the vehicle steers (steering wheel operation) in order to drive a curve, change lanes, and the like. Steering by the driver with respect to the vehicle, the longitudinal direction of the vehicle is the x-axis, the rotational motion (roll) around the x-axis, the lateral direction of the vehicle is the y-axis, the rotational motion around the y-axis (pitch), and up and down z. Generates three-dimensional sprung vehicle motion such as axial translational motion (heave). Therefore, the influence of the three-dimensional vehicle motion on the steering characteristic evaluation can be identified quantitatively from the magnitude of the identification parameter by identifying the steering motion of the driver as a driver model.

When a moving vehicle is steered, lateral acceleration is generated along with translational motion (side slip) in the y-axis direction and rotational (yaw) motion around the z-axis, thereby causing roll motion. For example, when step steering input is performed for a vehicle traveling at 72 km / h (20 m / s), the rotation speed (yaw rate) around the z-axis of the vehicle and the speed component in the x-axis direction of the center of gravity of the vehicle. Inverse positive contact (side slip angle) of the velocity component in the y-axis direction occurs, and the time for the side slip angle to reverse from positive to negative is about 0.2 seconds, during which the yaw angle is about 2 degrees. Therefore, skidding and yaw motion, which are minute planar motions at the initial stage of steering pole, cannot be ignored, and it is necessary to consider these planar motions as well. By the way, it is the mass of the vehicle in a broad sense that forms the inertial term related to the skid motion, and it is the yawing inertia moment that forms the inertial term related to the yaw motion.

In the evaluation of a vehicle controlled to have a pitch motion synchronized with the roll, it is known that the pitch associated with the roll is recognized as a yaw or a roll motion, not as a pitch motion (for example, non-patent literature). 1). From this, it is necessary to consider an index that combines the mass of the vehicle and the yaw moment of inertia, which centrally looks at both the skid motion and the yaw motion as a response at the initial stage of the minute steering pole.

By the way, a vehicle yawing moment of inertia is known as an index for evaluating yaw motion (see, for example, Non-Patent Document 2). The normalized vehicle yawing moment of inertia In is the vehicle yawing moment of inertia I, the vehicle inertia mass _m , the distance between the front axis and the center of gravity point l _f , and the distance between the rear axis and the center of gravity point l. If _r , it is represented by I / (m × l _f × _{l r} ), and in the case of a general passenger car, In is in the vicinity of 1. From this, the vehicle yawing moment of inertia I can be expressed by approximately m × l _f × l _r .

Hideki Sakai, Yasushi Yamamoto, "Damping force control that emphasizes transient turning sensation", Proceedings of the Society of Automotive Engineers of Japan, Society of Automotive Engineers of Japan, 2012, Vol. 43, No. 3, p. 709-716 Shuichi Nakamura, Sadayuki Tsugawa, Masaki Yamamoto, Nobuyuki Takeda, "Automobile Project Development Engineering-Environment, ITS, Athletic Performance, Logistics- (Lecture Text of" Automotive Engineering ", Faculty of Engineering, University of Tokyo)", Gihodo Publishing, May 1, 2001 , P. 136-137

Since the above-mentioned vehicle yawing moment of inertia I is the yawing moment of inertia around the center of gravity of the vehicle, the distance from the center of gravity is whether a heavy object such as an engine is in front of or behind the center of gravity of the vehicle. If they are the same, they will be the same size.

However, the response that the driver feels at the initial stage of the minute steering pole of the vehicle differs depending on the position of the heavy object, and the response at the initial stage of the minute steering pole of the vehicle is determined only by the magnitude of the yawing moment of inertia I around the center of gravity. Cannot be evaluated. Therefore, an index for evaluating the response at the initial stage of the minute steering pole of the vehicle is required, and it has been desired to provide a system or the like for calculating the index.

The present invention is a system for calculating an index for evaluating a response at the initial stage of steering of a vehicle in view of the above problems.
An input receiving means that accepts input of at least the mass m of the vehicle, the load distribution of the front and rear wheels of the vehicle ( _WF : _Wr ), and the distance l between the axles of the front wheels and the axles of the rear wheels of the vehicle.
Calculated based on the input mass m, load distribution (W _f : W _r ), and distance l, using the value corresponding to the yawing moment of inertia around the strike center against the lateral force acting on the front wheels at the initial stage of steering of the vehicle as an index. An index calculation system including a calculation means for performing is provided.

According to the present invention, it is possible to provide an index for evaluating a response (both skidding and yaw motion) at the initial stage of a minute steering pole of a vehicle, and it is possible to provide a system capable of providing the index. Become.

The figure which showed the plane 2 degree of freedom motion of a vehicle simplified. The figure which showed the position of the strike center by considering the lateral force acting on the front wheel at the initial stage of the steering pole as the strike force. The figure which showed the idea of degenerate derivation of the rotational motion around the center of gravity point and the translational motion of the center of gravity point as the motion around the center of gravity at the initial stage of the steering pole. The figure explaining the rotational motion around the strike center at the initial stage of a steering pole. The figure explaining the difference between the moment of inertia around the center of gravity point and the moment of inertia around the center of gravity due to the difference in the position of the engine. The figure which showed the relationship between the value corresponding to the moment of inertia around the center of gravity point and the value corresponding to the moment of inertia around the center of gravity due to the difference in the load distribution of the front and rear wheels. The figure which showed the specification of each car shown in FIG. The figure explaining the difference of the moment of inertia around the strike center depending on the position of a transmission. The figure which showed the configuration example of the system which calculates the index for evaluating the response at the initial stage of steering of a vehicle. The figure which showed an example of the hardware configuration of the system shown in FIG. The flowchart which showed an example of the process executed by the system shown in FIG.

The index calculation system of the present invention is a system for calculating an index for evaluating the response at the initial stage of steering of the vehicle, and evaluates both skidding and yaw motion as the response immediately after the driver operates the steering wheel. Calculate the index for. The vehicle may be a truck or the like as well as a passenger car. Hereinafter, the index calculated by the system will be described with the vehicle as a passenger car.

FIG. 1 is a simplified view showing the plane motion of the vehicle. The vehicle shown in FIG. 1 is a flat two-wheel model in which a four-wheeled vehicle is replaced with a vehicle equipped with two equivalent front and rear wheels. In the example shown in FIG. 1, the mass of the vehicle is m, the yawing moment of inertia of the vehicle is I, the vehicle speed is V, the vehicle side slip angle is β, the yaw rate is r, the steering angle is δ, and the lateral action acting on the front wheel axis (front axis). The force (cornering force) is 2Y _f , and the cornering force acting on the shaft (rear shaft) of the rear wheel is 2Y _r . 2Y _f is a cornering force for two front wheels, and 2Y _r is a cornering force for two rear wheels. Also, in the range where the skid angle is very small, the cornering stiffness for the two front wheels is 2K _f and the cornering stiffness for the two rear wheels is 2K _r for the rising gradient (cornering stiffness) of the cornering force with respect to the skid angle. do. Further, the distance between the front axle and the rear axle (wheelbase) is l, the distance from the front axle to the center of gravity of the vehicle is l _f , and the distance from the rear axle to the center of gravity of the vehicle is l _r .

Then, the equation of motion of the lateral motion of the vehicle can be expressed by the following equation 1.

The equation of motion of the yaw motion in the lateral motion can be expressed by the following equation 2.

Since the cornering forces F _yf and F _yr for each of the front and rear wheels are proportional to the cornering stiffness K _f and _Kr of the front and rear wheels and the side slip angle β of the front and rear wheels, they can be expressed by the following equation 3.

When the above formula 3 is applied to the above formulas 1 and 2, respectively, the following formulas 4 and 5 are obtained.

The skid angle β _f of the front wheels and the skid angle β _r of the rear wheels are expressed by the following equation 6.

By substituting the above equation 6 into each of the above equations 4 and 5, the following equations 7 and 8 are obtained.

By rearranging the above equations 7 and 8, it can be expressed by an equation of matrix notation as shown in the following equation 9.

By Laplace transforming both sides of the above equation 9, and rearranging them, it can be expressed as the following equation 10.

When the above equation 10 is modified, it becomes the following equation 11. In the formula 11, a ₁₁ , a ₁₂ , a ₂₁ , a ₂₂ and b ₁₁ are represented by the following formula 12.

The transfer function of the skid angle β and the yaw rate r with respect to the steering angle δ can be expressed as the following equations 13 and 14 based on the above equation 11.

In the above equations 13 and 14, the natural frequency ω _n and the damping coefficient ζ common to both are expressed by the following equations 15 and 16.

In the above formulas 15 and 16, A is called a stability factor and is expressed as the following formula 17.

In the above equation 14, G _δ ^r (0) is a yaw rate gain and is represented by the following equation 18. In the above equation 13, G _δ ^β (0) is a skid gain and is expressed by the following equation 19. In the above equation 14, _Tr is a yaw rate first-order advance time constant and is expressed by the following equation 20. In the above equation 13, T _β is a first-order advance time constant of the skid angle and is represented by the following equation 21.

The natural frequency ω _n or the like calculated by the above equations 15 to 21 is an index called a response parameter.

By the way, the vehicle motion at the initial stage of the steering pole (t → 0) can be described by the skid angle β and the yaw rate r as shown in the above equation 1. When the driver turns the steering wheel, it is considered that the lateral motion of the vehicle is felt as a complex response in which the skid angle β and the yaw rate r are combined according to the input of the steering angle δ. Therefore, it is assumed that the driver cannot completely separate and detect the side slip angle β and the yaw rate r that constitute the lateral motion. Then, as shown in the above equations 13, 19, and 20, the mass m of the vehicle as the responsiveness index of the side slip angle β is taken out by itself, and as shown in the above equations 14, 18, and 21, the vehicle mass m is taken out by itself. It is considered impossible to take out the yawing moment of inertia I as a response index of the yaw response by itself and express the complex response felt by the driver.

Referring to the above equations 13 and 14, since the order of the Laplace operator s in the denominator of the transfer function is 2, the skid angle β and the yaw rate r are delayed in the first-order response of the second order with respect to the steering angle δ. It can be thought of as a system. In the primary response delay system, since the output phase is delayed from the input phase, the skid angle β and the yaw rate r are delayed with respect to the input steering angle δ.

Referring to the above equation 6, at the moment when the steering angle δ is input (at the initial stage of steering pole), the skid angle β and the yaw rate r are very small, so that the skid angle β _r of the rear wheels becomes very small, and the rear wheel is rear. The lateral force generated by the ring is almost equal to zero. On the other hand, the side slip angle β _f of the front wheels includes the steering angle δ generated at the same time as steering. For this reason, at the initial stage of steering, the tire lateral force applied to the vehicle is only the front wheels.

In a vehicle, the front wheels are generally located in front of the center of gravity. Then, at the initial stage of the steering pole, the center of gravity of the front wheel, that is, the center of rotation at that moment, occurs behind the center of gravity on the x-axis about the front-rear direction of the vehicle.

With reference to FIG. 2, the position of the strike center at the initial stage of the steering pole will be described. Assuming that the distance between the center of gravity C _p and the center of gravity C _g is _xp , a lateral velocity v (= V × β) is generated at the impact center C _p , and the lateral velocity v and the yaw rate r are the arm lengths. It is balanced with the value obtained by multiplying the distance x _p . Based on this condition, the transfer function of the above equations 13 and 14 can be described as the following equation 22.

When the distance x _p between the center of gravity C _p and the center of gravity C _g with respect to the step input 1 / s is calculated using the above equation 22, it is obtained as the following equation 23.

The initial value x _p (0 ₊ ) of the distance x _p between the strike center C _p and the center of gravity point C _g with respect to the step input 1 / s is the initial value theorem representing the initial value (t = 0) of the original function of the Laplace transform. Can be calculated by the following equation 24.

As the approximate value of the yawing moment of inertia I, the following equation 25 described in Non-Patent Document 2 can be used.

When the above formula 25 is applied to the above formula 24, the distance x _p can be expressed as the following formula 26.

With reference to the above equation 26, it can be seen that the strike center C _p is near the distance of l _r rearward from the center of gravity point C _g . This indicates that it is near the rear axle connecting the two rear wheels.

On the other hand, the initial value theorem can be applied to the above equations 14 and 13, and the initial values of the yaw angular acceleration and the lateral acceleration of the center of gravity can be calculated by the following equations 27 and 28.

The time change of the lateral velocity v of the center of gravity point C _g is as shown in the following equation 29.

In the strike center C _p , the relationship shown in the following equation 30 is established based on the condition that the lateral velocity v and the value obtained by multiplying the yaw rate r by the distance x _p which is the length of the arm are balanced.

When the relationship shown in the above formula 30 is applied to the above formula 29, the relationship shown in the following formula 31 is derived.

With reference to the above equation 31, it can be seen that the consideration of the strike center at the initial stage of the steering pole does not violate the condition of the initial value obtained from the equation of motion. This is because the same result can be obtained by applying the relationship shown in the above equation 30. Therefore, in consideration of the striking heart, the side slip angle β with two degrees of freedom and the yaw rate r are treated in a unified manner, the front wheel lateral force is regarded as the striking force, and the responsiveness to the striking force is evaluated. Here, when β and r are handled in a unified manner, it will be described as being aggregated in r.

FIG. 3 is a diagram showing the concept of deriving the motion around the center of gravity C _p from the rotational motion around the center of gravity C _g and the translational motion around the center of gravity C _g at the initial stage of the steering pole. Let the vehicle be a rigid body, and consider the movement of the rigid body. The motion of a rigid body is composed of a rotational motion around the center of gravity of the rigid body and a translational motion of the center of gravity. The translational motion is a motion in which each point constituting the rigid body moves in parallel in the same direction (in this case, a motion in which the points move in parallel to either the left or right side). When rotational motion and translational motion occur at the same time, it is a synthetic motion that combines rotational motion and translational motion.

At the initial stage of the steering pole, it can be replaced with the rotation around the strike center near the center of the rear axle as described above. Considering the dimension of kinetic energy that can handle translational motion and rotational motion in common, and expressing the vehicle's moment of inertia I and yaw rate r, the rotational kinetic energy _Krot can be expressed by the following equation 32. ..

Next, consider the kinetic energy K _tran of the translational motion of the center of gravity. The kinetic energy K _tran is expressed by the following equation 33 using the mass m of the vehicle and the lateral velocity v. The lateral speed v is expressed by v = x _p x r using the distance x _p from the center of gravity to the center of gravity and the yaw rate r, and since the center of gravity is near the rear axis, the distance x _p is , The distance from the center of gravity to the rear axis can be replaced with l _r .

Since the total kinetic energy K _tot can be calculated by the sum of the rotational kinetic energy K _rot and the translational kinetic energy K _tran , the following equation 34 is derived.

Here, consider the kinetic energy when the vehicle is rotating at the yaw rate r around the strike center. Assuming that the center of gravity is on the rear axis and the distance x _p from the center of gravity to the center of gravity is equal to the distance l _r from the center of gravity to the rear axis, consider the moment of inertia I _p around the center of gravity. Since the yawing moment of inertia I around the center of gravity is known, the moment of inertia of the axis parallel to the axis passing through the center of gravity and at a distance l _r , that is, the moment of inertia I _p around the center of gravity is determined by the parallel axis theorem. It can be expressed as the equation 35 of.

The kinetic energy K _rp when the vehicle is rotating at the yaw rate r around the strike center is expressed by the following equation 36 using the moment of inertia I _p around the strike center and the yaw rate r.

The kinetic energy K _rp obtained by the above formula 36 is equal to the total kinetic energy K _tot obtained by the above formula 34. Therefore, the translational motion and the rotational motion at the initial stage of the steering pole can be replaced with the motion around the strike center. The difficulty of generating the motion around the strike center can be evaluated by the magnitude of the inertia of the rotation that tries to maintain the rotational motion around the strike center, that is, the value corresponding to the moment of inertia _Ip around the strike center. The moment of inertia around the center of gravity is not set to I _p , but the value equivalent to I _p . This is because they are thinking, not the moment of inertia at the exact position of the center of gravity. It can be considered that the smaller the value corresponding to the moment of inertia _Ip , the better the steering response at the initial stage of the steering electrode because the rotation can be performed with a smaller kinetic energy.

When evaluating using the moment of inertia _Ip around the strike center, the following points should be noted. FIG. 4 is a diagram illustrating a rotational motion around the strike center at the initial stage of the steering pole. For the sake of brevity, it is assumed in FIG. 4 that a striking force acts on the front wheels by steering and that the striking center _Cp , which is the center of rotation due to the striking force, is on the rear axle.

The equation of motion of rotation around the strike center can be expressed by the following equation 37 based on the above equation 5.

The equation of motion shown in the above equation 37 is the same equation of motion as the pendulum around the fixed axis. However, in the case of a pendulum, a restoring force works, but in this equation of motion, there is no restoration term, so it will continue to rotate. Therefore, it is not possible to apply Newton's law around the strike heart to describe the overall lateral motion of the vehicle (it cannot express the motion of the vehicle without limitation).

Vehicles such as passenger cars receive force only from the front wheels at the initial stage of steering. Therefore, considering the striking force from the front wheels and the striking center, it is not meaningless to adopt the moment of inertia _Ip around the striking center as an index indicating the response at the initial stage of steering and the ease of movement.

When the above formula 25 is applied to the above formula 36, it can be expressed as the following formula 38.

In the above formula 38, for the mass m of the vehicle and the wheelbase l, the values described in the vehicle verification, the catalog, etc. that must be carried in the vehicle can be used. In addition, the front axle load W _f and the rear axle load W _r are also described in vehicle verifications and catalogs. Therefore, the distance l _r from the center of gravity point to the rear axle can be calculated by the following equation 39 using the front axle load W _f and the rear axle load W _r .

From these facts, if the values described in the vehicle verification and catalogs are used, the moment of inertia _Ip around the strike center can be easily calculated from the above equation 38, and even without specialized knowledge, at the initial stage of steering. An index that can easily evaluate the response can be obtained.

The results of actually calculating the moment of inertia _Ip using the above equation 38 and verifying the usefulness of the obtained index are shown below. FIG. 5 is a diagram illustrating the difference between the moment of inertia around the center of gravity and the moment of inertia around the center of gravity due to the difference in the position of the engine. It is assumed that the center of gravity of the vehicle body of mass m _B excluding the engine of mass m _E is in the center of the wheelbase l of the vehicle. Vehicles are classified according to the position of the engine and the drive wheels. The drive wheels are classified as rear wheel RR, the engine is located between the front and rear axles, and the drive wheels are classified as rear wheel midship. Of the midships, vehicles with the engine located in front of the center of the wheelbase are classified as front midships, and vehicles with the engine located behind the center of the wheelbase are classified as rear midships.

In the case of the front midship, as shown in FIG. 5, since the heavy engine is located in front, the center of gravity of the entire vehicle is shifted forward by _x0 . Therefore, the axis in the left-right direction ( _y0 axis) passing through the center of gravity moves by about _x0 and becomes the y-axis. Assuming that the distance from the center of gravity of the entire vehicle to the engine is xE, the following equation 40 is established from the balance of the moments around the y-axis when the vehicle body is viewed from the side.

Solving the above equation 40 for x ₀ gives the following equation 41.

Here, assuming that the moment of inertia of the engine is _IE and the moment of inertia of the vehicle body is IB, the moment of _inertia I ₀ around the center of gravity of the entire vehicle can be expressed by the following equation 42 according to the parallel axis theorem. can.

In the case of the rear midship in which the engine shown in FIG. 5 is mounted behind the center of gravity point, the moment of inertia around the center of gravity point of the entire vehicle can be calculated in the same manner as described above. In these calculations, if the engine mass is the same and the engine is shifted by the same distance, the front midship and the rear midship will have the same result. The driver feels a difference in the response at the initial stage of steering, that is, the ease of movement between the front midship and the rear midship (for example, motor fan illustrated, Vol.94 midship combat power, front midship superiority pp. See .52-55 ISBN: 9784779622205), but the same result would not match the response felt by the driver.

For the front midship, the value I _iFM corresponding to the moment of inertia I _p around the strike center is calculated by the following equation 43.

For the rear midship, the value I _iRM corresponding to the moment of inertia I _p around the strike center is calculated by the following equation 44.

With reference to the above equations 43 and 44, the value of the rear midship is smaller than the value of the front midship, and the driver's value cannot be evaluated only by the conventional moment of inertia around the center of gravity obtained from the above equation 42. It was found to be a rational index for the response evaluation at the initial stage of the steering pole.

It should be noted that the mass of the entire vehicle is the sum of the mass of the engine and the mass of the vehicle body, and both the front midship and the rear midship have the same mass. In the conventional evaluation method using the yawing moment of inertia around the center of gravity, when both the front midship and the rear midship have the same mass, the yawing moment of inertia around the center of gravity also has the same value. The response evaluation of the time cannot be performed properly.

FIG. 6 is a diagram showing the relationship between the value corresponding to the moment of inertia around the center of gravity and the value corresponding to the moment of inertia around the center of gravity due to the difference in the load distribution of the front and rear wheels. The values corresponding to each moment of inertia shown in FIG. 6 were calculated using the above equations 25 and 38 based on the data obtained from vehicle verification, catalogs, and the like. In particular, we picked up three characteristic vehicles A, B, and C and evaluated them. The values of each result in FIG. 6 are the values of the results calculated for vehicles having different ratios of the front wheel load and the rear wheel load. Each value is a value when the ratio of the front wheel load and the rear wheel load is set to each ratio. The specifications of vehicles A, B, and C are shown in FIG.

The specifications of the vehicle are the specifications and data of the individual elements that make up the performance, properties, shape, etc. of the vehicle, and are the mass (kg), wheelbase (mm), front wheel load (%), and rear wheel load (%) of the vehicle. %) And so on. In FIG. 7, the distance from the center of gravity point to the front axis l _f (m), the distance from the center of gravity point to the rear axis l _r (m), and the moment of inertia I (kg) around the center of gravity point calculated based on these data.・ M ² ), moment of inertia around the center of gravity (kg ・ m ² ), and its ratio are included.

The vehicle A is a front-heavy lightweight FF vehicle in which the front wheel load is larger than the rear wheel load. Vehicle B is a lightweight FR vehicle with a front midship that has the same front wheel load and rear wheel load. The vehicle C is a rear heavy medium-weight RR vehicle in which the rear wheel load is larger than the front wheel load.

Comparing the vehicles A to C, the moment of inertia I around the center of gravity is the smallest in the vehicle A and the largest in the vehicle C. Further, the moment of inertia I around the center of gravity of the vehicle B is close to the moment of inertia I around the center of gravity of the vehicle A, and if only the moment of inertia I around the center of gravity is compared, the evaluations of the vehicles A and B are in competition. High, vehicle C has a low rating.

However, in terms of the actual feeling of the driver riding (general / subjective evaluation), the vehicle B has a higher evaluation than the vehicle A, and the vehicle B and the vehicle C have a competitive evaluation. By the way, the vehicle C is a European vehicle whose unique handling is often highly evaluated.

Therefore, when referring to the moment of inertia _Ip around the strike center of the vehicles A to C, the vehicle C is the smallest, the vehicle B antagonizes the vehicle C, and the vehicle A is the largest. This is almost in line with the above general and subjective evaluation. From this, it was found that the moment of inertia _Ip around the strike center represented by the above equation 38 is effective as an index for response evaluation at the initial stage of the steering pole.

FIG. 8 is a diagram illustrating a difference in the moment of inertia around the strike center depending on the position of the transmission. In an FR (front engine / rear drive) vehicle that drives the rear wheels, the mechanical energy (rotational energy) generated by the engine in front is used by the transmission to change the ratio of the rotational speed, and the rear axle is used as power. It is transmitted to the differential gear device (differential gear) provided in the above via the propeller shaft. The differential gear distributes power to the left and right tires.

As shown in FIG. 8A, in a normal transmission vehicle, the heavy engine and the transmission are integrally configured, so that the weight ratio on the front wheel side is high. In order to improve the maneuverability and maneuverability of the vehicle, it is effective to lower the center of gravity, collect heavy objects in the center of the vehicle, or balance the weight in front of and behind the vehicle. Therefore, in recent years, as shown in FIG. 8B, an increasing number of vehicles have adopted a trans-axle in which a heavy engine and a transmission are separated and the transmission is arranged on the rear axle side. A trans-askle vehicle is a vehicle in which the engine and transmission are separated and the transmission and differential gear are integrated.

In the normal transmission vehicle shown in FIG. 8A, in the case of the front midship, the engine is located between the front axle and the center of gravity point, and the transmission is located between the center of gravity point and the engine. Therefore, the transmission is relatively close to the center of gravity. On the other hand, in the transmission vehicle shown in FIG. 8B, since the transmission is integrated with the differential gear of the rear axle, the transmission is arranged at a position farther from the center of gravity than in a normal transmission vehicle. It will be.

When the transmission, which is a heavy object, is arranged at a position far from the center of gravity point, the moment of inertia I around the center of gravity point becomes large. Therefore, the trans-axle vehicle shown in FIG. 8 (b) is shown in FIG. 8 (a). The moment of inertia I around the center of gravity is larger than that of a normal transmission vehicle.

In the trans-axle vehicle shown in FIG. 8 (b), the transmission, which is a heavy object, is arranged near the rear axle where the impact center is located. Therefore, in the rotation centered on the impact center, the transmission is located far from the rear axle. , Compared with the normal transmission vehicle shown in FIG. 8 (a), it becomes easier to rotate. Therefore, the moment of inertia _Ip around the strike center is smaller in the trans-askle vehicle shown in FIG. 8 (b).

The fact that the moment of inertia I _p around the strike center is small indicates that the nose rotates around the strike center with a small force and the responsiveness at the initial stage of the steering pole is good. Although it is a driver's feeling, the fact that the trans-askle method is adopted for high-performance FR vehicles that specialize in kinetic performance is thought to be related to the small moment of inertia _Ip around the strike center. Be done. Even in the latest electric vehicles, there is a tendency to use a rear motor and a rear drive, which is also considered to be related to the small moment of inertia _Ip around the strike center.

From the above, when evaluating the response at the initial stage of steering of the vehicle, the moment of inertia I around the center of gravity cannot be properly evaluated only by the mass m of the vehicle and the yawing moment of inertia I around the center of gravity. Appropriate evaluation can be performed by introducing _p and using the moment of inertia I _p around the center of gravity.

The calculation method of the moment of inertia _Ip around the strike center is summarized below. The mass m of the vehicle, the wheelbase l, and the load distribution of the front and rear wheels ( _WF : _Wr ) can be obtained from data such as vehicle verification and catalogs. Therefore, it is possible to determine which method to adopt depending on whether or not the moment of inertia I around the center of gravity is known.

When the moment of inertia I around the center of gravity point is known, the distance l _f between the front axis and the center of gravity point and the distance l _r between the center of gravity point and the rear axis are calculated by the following equation 45.

Using the distances l _f and l _r calculated by the above formula 45, the moment of inertia I _p around the strike center of the vehicle is calculated by the following formula 46.

The above formula 46 is a formula in which the distance from the center of gravity to the center of gravity is the distance _lr from the center of gravity to the axis of the rear wheel. However, when the moment of inertia I around the center of gravity is known, the above formula is used. The distance l _f can be calculated from 45 and substituted into the above equation 26 to calculate the distance from the center of gravity to the center of gravity as I / (ml _f ). Therefore, the moment of inertia I _p around the strike center of the vehicle can be calculated by using the distance I / (ml _f ) instead of the distance l _r in the above equation 46.

If the moment of inertia I around the center of gravity is not known, the distance _lr is calculated by the above equation 45. The moment of inertia _Ip around the strike center of the vehicle is calculated by the following equation 47 using the calculated distance _lr .

As described above, an index for evaluating the response at the initial stage of steering of the vehicle can be provided, and an example of a system configuration for calculating the index is shown in FIG. The index calculation system can be configured by, for example, an information processing device such as a PC. The information processing device 10 is a general computer, and includes a CPU (Central Processing Unit) 20, a ROM (Read Only Memory) 21, a RAM (Random Access Memory) 22, and an HDD (Hard Disk Drive) 23. It includes an output I / F 24, a communication I / F 25, a bus 26, an input device 27, and a display device 28. The information processing apparatus 10 may include a DVD-RW (Digital Versatile Disk Rewritable) drive, a media I / F, a microphone, a speaker, and the like.

The CPU 20 controls the operation of the entire information processing apparatus 10. The ROM 21 stores a program used to drive the CPU 20. The RAM 22 provides a working area for the CPU 20. The HDD 23 stores various programs and data.

The input / output I / F 24 is an interface for connecting the input device 27 and the display device 28. The input device 27 is a device for inputting various instructions such as a mouse and a keyboard, characters, numbers, and the like. The display device 28 is a device that displays a cursor such as a display, a pointer, a menu, characters, numbers, images, and the like.

The communication I / F 25 is an interface for communicating data using the network 12. The bus 26 is an address bus, a data bus, or the like for electrically connecting each component such as the CPU 20.

FIG. 10 is a block diagram showing an example of the functional configuration of the information processing apparatus 10. Each function included in the information processing apparatus 10 can be realized by a processing circuit such as a CPU 20. The processing circuit is a processor programmed to execute each function by a program, an ASIC (Application Specific Integrated Circuit) designed to execute each function, a DSP (Digital Signal Processor), and an FPGA (Field Programmable Gate). Array) etc. shall be included.

The information processing device 10 includes an input receiving unit 30, a calculation unit 31, and a control unit 32. The input receiving unit 30 receives inputs of the mass m of the vehicle, the wheelbase l, and the load distributions W _f and W _r of the front and rear wheels, which are data such as vehicle verification and catalogs. When the moment of inertia I around the center of gravity is known, the input receiving unit 30 can also receive the input of the moment of inertia I around the center of gravity.

The calculation unit 31 determines whether or not the input reception unit 30 has received the input of the moment of inertia I around the center of gravity. When accepted, the calculation unit 31 calculates the distance _lr from the center of gravity point to the rear axis by the above equation 45. The distance from the center of gravity to the center of gravity may be calculated by the above I / (ml _f ). Then, the calculation unit 31 calculates the moment of inertia _Ip around the strike center by the above equation 46. On the other hand, if it is not accepted, the calculation unit 31 calculates the distance _lr from the center of gravity point to the rear axis by the above equation 45. Then, the calculation unit 31 calculates the moment of inertia _Ip around the strike center by the above equation 47.

The control unit 32 evaluates the response at the initial stage of the steering pole of the vehicle based on the moment of inertia _Ip around the strike center calculated by the calculation unit 31, and displays the evaluation result on a display unit such as a display. The control unit 32 can compare with the moment of inertia _Ip around the strike center of another vehicle calculated by the calculation unit 31 and evaluate whether the response is good or bad depending on the magnitude of the moment of inertia Ip. This makes it possible to evaluate the response at the initial stage of the steering electrode in vehicles having different drive systems such as FF, FR front midship, and RR, and the response at the initial stage of the steering electrode between vehicles having the same drive system.

In order to facilitate such evaluation, the control unit 32 may create a graph as shown in FIG. 7 and display it on the display unit. The information processing device stores the calculated moment of inertia _Ip around each hitting center in association with the vehicle identification information for identifying the vehicle in order to create such a graph and display it on the display unit. Can be provided. As the vehicle identification information, a vehicle name described in a vehicle verification, a catalog, or the like can be mentioned.

FIG. 11 is a flowchart showing an example of the processing executed by the index calculation system. This process starts from step 100, and in step 101, input of data such as vehicle verification and a catalog is accepted. The input data includes at least the mass m of the vehicle, the wheelbase l, the load distribution W _f of the front and rear wheels, and W _r . It should be noted that these data may be stored in association with the vehicle name in advance, the input of the vehicle name may be accepted, and these data may be acquired based on the input vehicle name.

In step 102, it is determined whether or not the input of the moment of inertia I around the center of gravity is accepted. If accepted, the process proceeds to step 103, and the distance l _r from the center of gravity to the rear axle is calculated by the above equation 45 using the wheelbase l, the load distribution W _f of the front and rear wheels, and W _r among the input data. do. Then, in step 104, the moment of inertia I _p around the center of gravity is calculated by the above equation 46 using the mass m of the vehicle, the moment of inertia I around the center of gravity, and the calculated distance l _r .

On the other hand, when the input of the moment of inertia I around the center of gravity is not accepted in step 102, the wheelbase l, the load distributions W _f and W _r of the front and rear wheels are used among the input data, and the above equation 45 is used. Calculate the distance _lr from the center of gravity to the rear axle. Then, in step 106, the moment of inertia _Ip around the strike center is calculated by the above equation 47 using the mass m of the vehicle, the wheelbase l, and the calculated distance _lr .

In step 107, the response at the initial stage of the steering pole of the vehicle is evaluated based on the calculated moment of inertia _Ip around the strike center, and the evaluation result is displayed. The evaluation result is, for example, "Because the moment of inertia _Ip around the strike center is smaller than that of the vehicle A, the responsiveness at the initial stage of the steering pole is better than that of the vehicle A." Since this is an example, the evaluation results are not limited to this. After displaying the evaluation result, the process proceeds to step 108 to end this process.

As described above, it is possible to calculate and provide an index for evaluating the response at the initial stage of the steering electrode. By providing this index, the kinetic performance of the vehicle can be optimized.

Although the index calculation system and the program of the present invention have been described in detail with the above-described embodiments, the present invention is not limited to the above-mentioned embodiments, and other embodiments, additions, changes, and deletions are made. Such as, can be changed within the range that can be conceived by those skilled in the art, and is included in the scope of the present invention as long as the action / effect of the present invention is exhibited in any of the embodiments.

10 ... Information processing device 20 ... CPU
21 ... ROM
22 ... RAM
23 ... HDD
24 ... Input / output I / F
25 ... Communication I / F
26 ... Bus 27 ... Input device 28 ... Display device 30 ... Input reception unit 31 ... Calculation unit 32 ... Control unit

Claims (6)

It is a system that calculates an index for evaluating the response at the initial stage of steering of the vehicle.
Input reception that accepts input of at least the mass m of the vehicle, the load distribution ( _WF : _Wr ) of the front and rear wheels of the vehicle, and the distance l between the axles of the front wheels and the axles of the rear wheels of the vehicle. Means and
Based on the input mass m, the load distribution (W _f : W _r ), and the distance l, it corresponds to the yawing moment of inertia around the strike center with respect to the lateral force acting on the front wheels at the initial stage of the steering pole of the vehicle. An index calculation system including a calculation means for calculating a value as an index. When the input receiving means receives the input of the vehicle yawing moment of inertia I around the center of gravity of the vehicle, the calculation means of the vehicle is based on the load distribution (W _f : W _r ) and the distance l. The distance lf from the axis of the front wheel to the center of gravity of the vehicle is calculated, and based on the calculated distance _lf , the mass m, and the moment of _inertia I of the vehicle yawing, the action is applied to the front wheel of the vehicle from the center of gravity of the vehicle. The distance to the center of inertia (I / (ml _f )) with respect to the lateral force to be applied is calculated, and the value obtained by multiplying the square of the calculated distance (I / (ml _f )) by the mass m is added to the value obtained. The index calculation system according to claim 1, wherein the index is calculated by adding the vehicle yawing moment of inertia I. When the input receiving means receives the input of the vehicle yawing moment of inertia I around the center of gravity of the vehicle, the calculation means of the vehicle is based on the load distribution (W _f : W _r ) and the distance l. The distance rl from the center of gravity of the vehicle to the axis of the rear wheel of the vehicle is calculated as the distance from the center of gravity to the center of inertia with respect to the lateral force acting on the front wheels of the vehicle, and the calculated distance _ll is _squared . The index calculation system according to claim 1, wherein the index is calculated by adding the vehicle yawing moment of inertia I to the value obtained by multiplying the mass m. When the input receiving means does not receive the input of the vehicle yawing moment of inertia around the center of gravity of the vehicle, the calculation means has the center of gravity of the vehicle based on the load distribution (W _f : W _r ) and the distance l. The distance _rl to the axis of the rear wheel of the vehicle is calculated as the distance from the point to the center of gravity with respect to the lateral force acting on the front wheel of the vehicle, and the calculated distance _rl and the distance received by the input receiving means are received. The index calculation system according to claim 1, wherein the index is calculated by multiplying l by the mass m. A storage means for storing each of the vehicle identification information for identifying one or more vehicles in association with each index calculated for each vehicle.
The input receiving means receives input of at least one vehicle identification information in addition to the mass, the load distribution, and the distance, and the calculation means receives an index based on the mass, the load distribution, and the distance. After calculating, at least one index associated with the at least one vehicle identification information is acquired from the storage means, and the acquired at least one index is compared with the calculated index to steer the vehicle. The index calculation system according to any one of claims 1 to 4, which includes a control means for evaluating an initial response. It is a program for causing a computer to execute a process of calculating an index for evaluating the response at the initial stage of steering of a vehicle.
At least a step of accepting inputs of the mass m of the vehicle, the load distribution ( _WF : _Wr ) of the front and rear wheels of the vehicle, and the distance l between the axles of the front wheels and the axles of the rear wheels of the vehicle. ,
Based on the input mass m, the load distribution (W _f : W _r ), and the distance l, it corresponds to the yawing moment of inertia around the strike center with respect to the lateral force acting on the front wheels at the initial stage of the steering pole of the vehicle. A program that executes a step of calculating a value as an index.

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