KR20160046747A - Steering supporting apparatus for vehicle - Google Patents

Abstract

Provided is a steering assist apparatus (10) for a vehicle, including a transmission device (22) configured to transmit a force and a displacement relating to steering between a steering wheel (18) and steered wheels (20L, 20R), a power steering device (12) configured to apply an assist torque to the transmission device, and a control device (50). When assuming the steering wheel, the transmission device, the power steering device, and the steered wheels as a steering system, the control device is configured to calculate, based on a product of a steering angular velocity and a derivative of the steering angular velocity, a product of the steering angular velocity and a steering torque, and a product of a steering angle and a derivative of the steering torque, a change rate (dDE) of an energy of the steering system, and control the assist torque based on the change rate of the energy of the steering system.

Description

{STEERING SUPPORTING APPARATUS FOR VEHICLE}

The present invention relates to a steering assist apparatus for a vehicle, and more particularly, to a steering assist apparatus that supports steering by adjusting a force relating to steering.

BACKGROUND ART [0002] Vehicles such as automobiles are generally equipped with a steering assist device that supports steering by adjusting a force related to steering, such as a steering assist force. This type of steering assist device is preferable not only to reduce the driver's steering burden but also to adjust the steering-related force in accordance with the driver's intention.

For example, the following Patent Document 1 related to the applicant of the present application discloses a steering assist device for changing the adjustment of the force with respect to steering according to whether or not the steering uniformity rate is calculated and the magnitude of the steering uniformity rate is larger than the reference value . In particular, the steering uniformity is calculated as the product of the steering angular speed and the steering torque and the product of the steering angle and the differential value of the steering torque. According to the steering assist device described in Patent Document 1, the force relating to the steering can be adjusted in a manner better reflecting the intention of the driver than when the magnitude of the steering uniformity is not considered.

International Publication No. 2014-087546

[Problems to be solved by the invention]

However, according to the configuration described in Patent Document 1, even if it is discriminated whether the magnitude of the steering uniformity rate is larger than the reference value, the adjustment of the power relating to the steering can not be appropriately changed depending on the steering situation.

For example, even if steering is started in a state where the steering wheel is in a neutral region (a straight forward position or a vicinity of the vehicle), steering torque does not occur immediately, and in a steering range in which the steering range from the neutral position is small, The size of the steering uniformity is very small. Therefore, in the situation where the steering wheel is in the neutral region, even if it is discriminated whether the magnitude of the steering uniformity rate is larger than the reference value, the adjustment of the force with respect to the steering can not be appropriately changed in accordance with the steering situation.

In the case where the driver rotates the steering wheel in the neutral region while the driver is resistant to the self-aligning torque, a suitable drag or damping force is given to the rotation of the steering wheel so that the driver can steer the steering wheel desirable. On the other hand, when the steering wheel is rotated toward the neutral position by the self-aligning torque in the vicinity of the neutral position, the drag force against the rotation of the steering wheel is preferably low so that the steering wheel quickly returns to the neutral position Do.

According to the structure disclosed in Patent Document 1, when the steering wheel rotates toward the neutral position in the vicinity of the neutral position, it is determined whether the rotation of the steering wheel is caused by the operation of the driver, Can not be determined. Therefore, it is not possible to appropriately change the steering force or the like in accordance with the steering situation. Further, in order to distinguish and determine the situation, it is necessary to determine whether or not the driver is putting his hand on the steering wheel, that is, a so-called hand-off situation.

Further, when the steering wheel is rotated by the driver's steering operation and the steering wheel is rotated by the force received from the road surface such as the self-aligning torque, if the rotational directions of the steering wheel are the same, . Therefore, even if the magnitude of the steering uniformity is determined to be larger than the reference value, the adjustment of the steering force can not be appropriately changed in accordance with the steering situation.

The present invention has been made in view of the above-described circumstances in the steering assist system described in Patent Document 1. It is a principal object of the present invention to provide an improved steering assist device relating to the above.

[Means for Solving the Problems and Effects of the Invention]

According to one embodiment of the present invention, there is provided a steering apparatus including a steering wheel operated by a driver, a steering wheel, and a transmitting device for transmitting a force and a displacement relating to steering between the steering wheel and the steered tire wheel A steering force applying device which is applied to a vehicle provided with an adjusting force applying device for giving an adjusting force for adjusting a force relating to steering to the transmitting device and a control device for controlling an adjusting force applied to the transmitting device by the adjusting force applying device Wherein the steering angle detecting device includes a steering angle detecting device for detecting a steering angle and a steering torque detecting device for detecting a steering torque, and the control device obtains a steering angle, a differential value of the steering angle and a differential value of the steering torque, The transmission device, the adjusting force applying device, and the steering wheel as a steering system, the product of the steering angular speed and the differential value of the steering angular speed, Wherein the vehicle steering assist apparatus calculates the rate of change of the energy of the steering system based on the product of the steering torque and the steering angle and the derivative of the steering angle and the steering torque and controls the steering force based on the rate of change of the steering system energy / RTI >

According to the above configuration, the rate of change of the steering system energy is calculated based on the product of the steering angular speed and the derivative of the steering angular speed, the product of the steering angular speed and the steering torque, and the derivative of the steering angle and the steering torque , And the adjustment force is controlled based on the change rate of the energy of the steering system. Since the rate of change of the steering system energy represents the direction and degree of input of energy to the steering system, the steering force can be controlled according to the input direction and degree of energy to the steering system. Also, as will be described later in detail, the input of the energy of the steering system depends on whether the change rate of the energy of the steering system is a large value as a rate of change of increase or a large value as a rate of change of decrease, Positive) input steering wheel is a reverse input by receiving a force from the road surface.

In particular, the rate of change of the energy of the steering system is calculated based on the product of the steering angular speed and the differential value of the steering angular speed. The differential value of the steering angular velocity and the steering angular velocity greatly changes from the steering torque and its differential value even when steering is started in a situation where the steering wheel is in the neutral region. Therefore, compared with the case of judging based on the steering torque ratio described in Patent Document 1, which does not include the product of the steering angular speed and the differential value of the steering angular speed, in the situation where the steering wheel is in the neutral region, It can be properly controlled.

Further, the situation in which the steering wheel rotates can be determined early, compared with the case where the product of the steering angular velocity and the differential value of the steering angular velocity is not considered. Therefore, even when the driver starts the quick steering operation, for example, the driver can be assisted effectively by controlling the adjustment force early by determining the state of the input. Even when the driver hands off the steering wheel at the end of turning and the steering wheel is quickly returned to the neutral position by the self-aligning torque in the vicinity of the neutral position, the situation of the reverse input is determined early , The adjusting force can be controlled so that the drag force against the rotation of the steering wheel is reduced. In this case, it is not necessary to judge whether or not the hand drop situation is present.

In addition, when the steering wheel is rotated (positive input) by the driver's steering operation and the steering wheel is also rotated by the force received from the road surface (reverse input) and their rotational directions are the same, Although not outside, the steering wheel rotates. According to the above configuration, since the product of the steering angular velocity and the differential value of the steering angular velocity is considered, the above-described rotation of the same direction can also be determined. Therefore, when the positive input and the reverse input to the steering system are in phase The adjustment force can be controlled.

In the above configuration, the control device is characterized in that the inertia yaw moment based on the mass of the movable member including at least the steering wheel and the differential value between the steering angular velocity and the steering angular velocity, The derivative of the product of the product of the steering angular speed and the steering torque and the product of the steering angle and the differential value of the steering torque may be calculated as the rate of change of the energy of the steering system.

According to the above configuration, as described in detail later, it is possible to calculate the rate of change of the energy of the steering system as the sum of the rotational energy and the elastic energy corresponding to the internal energy and the PV day in the enthalpy theory of thermodynamics have. Therefore, it is possible to accurately determine whether the input / output of energy to the steering system, that is, the input state of energy to the steering system, is a positive input or a reverse input.

When the change rate of the energy of the steering system is the change rate of the increase, the steering assist force is set to be larger than that when the change rate of the energy of the steering system is not the change rate of the increase It may be increased.

According to the above configuration, when the rate of change of the energy of the steering system is the rate of change of increase, that is, when the energy is inputted into the steering system, the steering assist force is increased can do. Therefore, when the steering operation is being performed by the driver, the assistance of the driver's steering operation is increased by correcting the increase in the steering assist force, thereby making it easier for the driver to perform the steering operation.

In the above arrangement, the steering force is at least one of the steering damping force and the steering frictional force, and when the rate of change of the energy of the steering system is a rate of decrease of the steering system, At least one of the steering damping force and the steering frictional force may be increased as compared with the case where the steering gear is not used.

According to the above arrangement, at least one of the steering damping force and the steering frictional force can be increased when the change rate of the energy of the steering system is the change rate of decrease, as compared with the case where the change rate of the energy of the steering system is not the change rate of decrease. Therefore, when the steering operation is not performed by the driver, at least one of the steering damping force and the steering frictional force is increased and the degree of rotation of the steering wheel by the disturbance received from the road surface by the steered tire is reduced, The stability can be improved.

In the above configuration, the control device determines whether the input state of the energy to the steering system is the state of the constant input by the driver's steering or the state of the reverse input by the steering wheel receiving the force from the road surface , The amount of correction of the steering assist force in the situation of reverse input is made smaller than the amount of correction amount of the steering assist force in the situation of positive input, .

According to the above configuration, since the steering assist force is controlled based on both the change rate of the steering system energy and the input state of the energy to the steering system, the steering assist force Can be more preferably controlled. That is, when the input state of the energy to the steering system is the input state by the driver's steering, the magnitude of the correction amount of the steering assist force can be made smaller than in the case of the reverse input state, It is possible to reduce the risk of overheating.

In the above configuration, the control device determines whether the input state of the energy to the steering system is the state of the correct input based on the steering of the driver, the state of the reverse input caused by the steering wheel receiving the force from the road surface, The amount of correction of at least one of the steering damping force and the steering frictional force in the reverse input state is larger than the magnitude of at least one correction amount of the steering damping force and the steering frictional force in the forward input state, The amount of correction of at least one of the damping force and the steering friction force may be changed.

According to the above configuration, at least one of the steering damping force and the steering frictional force is controlled based on both the change rate of the steering system energy and the input state of the energy to the steering system, so that when the input state of the energy to the steering system is not determined At least one of the steering damping force and the steering frictional force can be more preferably controlled. That is, the magnitude of at least one of the steering damping force and the steering frictional force in the reverse input situation is larger than the magnitude of at least one correction amount of the steering damping force and the steering frictional force in the positive input state. Therefore, in the reverse input situation, at least one of the steering damping force and the steering frictional force can be made larger than the situation of the positive input, and the fear that the steering wheel is rotated due to disturbance from the road surface of the steered tire can be reduced more effectively .

Further, in the above arrangement, the control device determines whether or not the state of the input of the energy to the steering system based on the product of the differential value of the steering torque and the steering torque and the rate of change of the energy of the steering system, It may be determined whether or not the situation of the input is the situation of the reverse input by the steering wheel receiving the force from the road surface.

According to the above configuration, the change rate of the energy of the steering system and the differential value of the steering torque and the steering torque provided for the calculation are used to determine whether the input state of the energy to the steering system is the state of the positive input or the state of the reverse input . In addition, a special device for determining the input direction such as two torque sensors is unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically showing a first embodiment of a steering assist system for a vehicle according to the present invention; Fig.
2 is a block diagram of an assist torque calculating device for calculating the assist torque Ta in the first embodiment.
3 is a flowchart for calculating a correction gain by the correction gain calculation block shown in FIG.
4 is a block diagram of an assist torque calculating apparatus for calculating an assist torque Ta in a second embodiment of the steering assistance system for a vehicle according to the present invention.
5 is a flowchart (first half) for calculating a correction gain by a correction gain calculation block in the second embodiment.
6 is a flowchart (second half) for calculating the correction gain by the correction gain calculation block in the second embodiment.
7 is a diagram showing a model of the steering apparatus for calculating the rate of change dDE of the driving energy.
Fig. 8 is a diagram showing an example of changes in the rate of change dDE of driving energy and the variation rate PS described in Patent Document 1 with respect to a situation in which the steering direction is reversed.
Fig. 9 is a diagram showing an example of changes in the driving force energy change rate dDE and the uniformity PS described in Patent Document 1 with respect to a situation in which the hands are laid in the second half of the reciprocating steering.
10 is a graph showing an example of change in the rate of change dDE (upper end) of the driving energy and the index value Iin (lower end).
11 is a view showing another example of the change in the rate of change dDE (upper end) and the value Iin (lower end) of driving energy.
Fig. 12 is a diagram showing the relationship between the steering angle &thetas; at a certain vehicle speed and the control current Ic to the electric power steering apparatus and the permissible range thereof.

[First Embodiment]

Fig. 1 is an explanatory view schematically showing a first embodiment of a steering system 10 for a vehicle according to the present invention. The steering assistance device 10 of this embodiment is applied to a vehicle 14 equipped with a column assist electric power steering device (EPS) 12. Further, the electric power steering device may be a power steering device of another type, such as a rack coaxial electric power steering device, for example, a rack coaxial type, as long as the assist torque can be controlled.

In Fig. 1, the vehicle 14 is provided with a steering device 16, which is a steering system of the vehicle. The steering apparatus 16 includes a steering wheel 18 operated by a driver, left and right front wheels 20L and 20R as steering wheels and steering wheel 18 and front wheels 20L and 20R. And a transmission device 22 for transmitting a force and a displacement with respect to each other. The transmission device 22 includes an upper steering shaft 24 that rotates together with the steering wheel 18, an intermediate shaft 26, and a steering mechanism 28. The intermittent shaft 26 is connected to the lower end of the upper steering shaft 24 via the universal joint 30 at the upper end and is connected to the pinion shaft 28 of the steering mechanism 28 via the universal joint 32 at the lower end 34).

The steering mechanism 28 includes a rack-and-pinion type steering unit 36 and tie rods 38L and 38R. The steering unit 36 includes a pinion shaft 34, To linear motion in the horizontal direction, and conversely, the reverse conversion is performed. The tie rods 38L and 38R are pivotally attached to the front end of the rack bar 40 at the inner end and the outer ends of the tie rods 38L and 38R are connected to the left and right front wheels 20L and 20R. (Not shown) of the knuckle arms 42L and 42R.

The rotational displacement and the rotational torque of the steering wheel 18 are converted by the transmitting device 22 into the oscillating and rotating torque around the king pin axis (not shown) of the front wheels 20L and 20R, 20R. The oscillating and rotating torque around the king pin axes received by the left and right front wheels 20L and 20R from the road surface 44 is transmitted to the steering wheel 18 as rotational displacement and rotational torque respectively by the transmitting device 22 .

The steering assist device (10) has an electric power steering device (12). 1, the power steering device 12 includes an electric motor 46 and a conversion device 48, but the conversion device 48 includes a worm gear fixed to the rotary shaft of the electric motor 46 and a worm gear fixed to the upper steering shaft 24, respectively. The rotation torque of the electric motor 46 is converted into rotation torque around the upper steering shaft 24 by the conversion device 48 and transmitted to the upper steering shaft. Therefore, the power steering device 12 functions as an adjusting force applying device for giving an assist torque as an adjusting force for adjusting the steering-related force to the upper steering shaft 24 of the transmitting device 2. [

The steering assist device 10 has an electronic control device 50. [ The electronic control unit 50 controls the rotation torque of the electric motor 46 to control the assist torque applied to the upper steering shaft 24 by the power steering device 12 And functions as a device. Signals indicating the steering angle? And the steering torque T are inputted from the steering angle sensor 52 and the torque sensor 54 provided on the upper steering shaft 24, respectively. A signal representing the vehicle speed V is also input to the electronic control unit 50 from the vehicle speed sensor 56. [

The electronic control device 50 includes a microcomputer having a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other by a bidirectional common bus. The ROM includes a control program, And so on. The steering angle sensor 52 and the torque sensor 54 detect the steering angle &thetas; and the steering torque Ts in the case of steering in the leftward turning direction of the vehicle.

The microcomputer of the electronic control unit 50 calculates an assist torque torque Tt based on the steering angle?, The steering torque T, and the vehicle speed V according to the block diagram shown in Fig. 2 and the flowchart shown in Fig. And functions as a device 62.

First, the block diagram shown in Fig. 2 will be described. In addition, the drawings in each block shown in Fig. 2 schematically show a map used in the calculation in the corresponding block.

The assist torque calculating device 62 calculates the target assist torque Tat as a sum of the basic assist torque, the attenuation control amount, the friction control amount, and the return control amount for returning the steering wheel 18 to the neutral position. The assist torque calculation device 62 has a basic assist torque calculation block 64, an attenuation control amount calculation block 66, a friction control amount calculation block 68 and a feedback control amount calculation block 70. [ The assist torque calculation device 62 has a gain calculation block 72 for the attenuation control amount, a gain calculation block 74 for the friction control amount, and a gain calculation block 76 for the feedback control amount.

The basic assist torque calculation block 64 calculates the basic assist torque Tab based on the steering torque T and the vehicle speed V so that the larger the steering torque T becomes, the larger the steering torque T becomes and the smaller the vehicle speed V becomes. The signal representing the basic assist torque Tab is output to the multiplier 78. [

The attenuation control amount calculation block 66 calculates the attenuation control amount Td based on the differential value d? Of the steering angle so that the larger the magnitude of the differential value (steering angular velocity) d? Of the steering angle? The gain calculation block 72 for the attenuation control amount is set such that the gain Kd for the attenuation control amount is smaller in the low speed range than in the micro speed range and increases in the middle speed range as the vehicle speed V becomes higher And calculates a gain Kd for the attenuation control amount. The signal indicating the attenuation control amount Td and the signal indicating the gain Kd for the attenuation control amount are outputted to the multiplier 80 and outputted as a signal indicating the product Td · Kd of the attenuation control amount Td calculated by the multiplier 80 and the attenuation control amount gain Kd Is outputted to the multiplier 82 as the post-correction damping control amount Tda.

In the friction control amount calculation block 68, a signal indicating the friction torque Tf calculated by the friction torque calculation block 84 based on the steering torque T and a signal indicating the steering angle? Are inputted. The friction control amount calculation block 68 calculates a basic friction control amount Tfb based on the friction torque Tf and the steering angle?. The gain calculation block 74 for friction control amount calculates the friction control amount gain Kf based on the vehicle speed V so as to increase as the vehicle speed V becomes higher in a low middle speed range and becomes a constant value in a high speed range. The signal indicating the basic friction control amount Tfb and the signal indicating the gain Kf for the friction control amount are outputted to the multiplier 86 and multiplied by the product Tfb · Kf of the basic friction control amount Tfb calculated by the multiplier 86 and the gain for friction control amount Kf Is outputted to the multiplier 88 as the corrected friction control amount Tfa.

The friction torque Tf is a torque acting as a friction drag against the driver's steering operation. For example, the friction torque Tf may be calculated according to the teachings of Japanese Patent Application Laid-Open No. 2009-126244 filed by the present applicant.

In the return control amount calculation block 70, a signal indicating the deviation? D? Of the steering angular velocity is inputted. The deviation? D? Of the steering angular velocity is calculated by subtracting the steering angular velocity d? By the adder 92 from the target steering angular velocity d? T calculated by the target steering angular velocity calculation block 90 based on the steering angle?. The feedback control amount calculation block 70 calculates the feedback control amount Tr based on the deviation? D? Of the steering angular velocity so that the magnitude becomes larger as the deviation? D? Of the steering angular velocity becomes larger. The gain calculation block 76 for the return control amount calculates the gain Kr for the return control amount based on the vehicle speed V so that the gain control block gain calculation block 76 becomes smaller as the vehicle speed V becomes higher and becomes a constant value in the high speed range. The signal indicating the return control amount Tr and the signal indicating the return control amount gain Kr are output to the multiplier 94 and represent the product Tr · Kr of the feedback control amount Tr calculated by the multiplier 94 and the gain for return control amount Kr The signal is output to the multiplier 96 as the feedback control amount Tra after correction.

2, in the maps of the blocks 64, 66, 70, 84, and 90, values such as the basic assist torque Tab and the like to be calculated are shown only for the positive values, such as the steering torque T It is not. However, the value to be calculated when the variable is a negative value is a point symmetric value of the value shown with respect to the origin.

The assist torque calculation device 62 includes a correction gain calculation block 98 for calculating the rate of change dDE of the driving energy with respect to the steering device 16 and calculating a correction gain for the basic assist torque Tab or the like based on the rate of change dDE, Lt; / RTI > The rate of change dDE of the driving energy is a value calculated based on the model 100 of the steering device 16 (steering system) shown in Fig.

As shown in Fig. 7, in the model 100, the driver's hand 102 and the rigid steering wheel 18 are referred to as a steering wheel 18 '. Also, the mass of the main movable member of the steering apparatus 16 is concentrated on the steering wheel 18 ', and the inertial yaw moment of the steering wheel 18' is I. The steering apparatus 16 except for the steering wheel 18 is an elastic body having a spring constant k of a torsional deformation and not having a mass.

The driving energy DE of the model 100, which is the energy held by the model 100, is the sum of the rotational energy and the elastic energy corresponding to the internal energy and the PV in the thermodynamic enthalpy theory, respectively. Therefore, the driving energy DE of the model 100 is represented by the following equation (1), assuming that the differential value of the steering angle?, Which is the rotational angle of the steering wheel 18 ', is d?.

The torque Tsat, which is generated when the end of the transmission device 22, that is, the end on the steering wheel 18 'side, is rotated by the angle? By the force from the steering wheel side, is Tsat, (2).

From the above equations (1) and (2), therefore, the driving energy DE of the model 100 is expressed by the following equation (3).

The inflow of energy into the model 100 and the outflow of energy from the model 100, i.e., the change in the driving energy DE of the model 100, can be judged by the sign of the differential value. By differentiating the equation (3), the differential value of the driving energy DE, that is, the rate of change dDE is expressed by the following equation (4).

Since the sign of the steering torque T is opposite to the sign of the torque Tsat and -Tsat = T, the equation (4) can be rewritten to the following equation (5), assuming that the differential value of the steering torque T is dT. (1), (2) and (3) of the following formula (5) are referred to as PO terms, P1 terms and P2 terms, respectively.

The correction gain calculation block 98 calculates a correction gain for each control amount in accordance with the flowchart shown in Fig. The drawings in the frames of each step shown in Fig. 3 schematically show the maps used in the calculation in the corresponding step. 3 is executed by the electronic control unit 50 repeatedly at predetermined time intervals when the ignition switch not shown in Fig. 1 is turned on. This also applies to the control according to the flowchart shown in Figs. 5 and 6 in the second embodiment described later.

First, in step 10, a signal indicating the steering angle? Detected by the steering angle sensor 52 is read. In step 20, the differential value d? Of the steering angle?, The differential value dd? The differential value dT of the steering torque T is calculated. The differential value d? Of the steering angle may be a value detected as the steering angular velocity, and the second differential value dd? Of the steering angle may be calculated as the differential value of the detected steering angular velocity d ?.

In step 30, the rate of change dDE of the driving energy DE is calculated according to the above equation (5). The inertial yaw moment I in the calculation of the rate of change dDE may not be a value considering the mass of all the movable members of the driver's hand and the steering device 16. [ For example, the inertia yaw moment I is a value based on the mass of the driver ' s hand and the steering wheel 18, the value of the driver's hand, the steering wheel 18 and the rotational member (the upper steering shaft 24, (26), and the like).

In step 40, the rate of change dDE of the driving energy DE is subjected to the low-pass filter process so that the rate of change dDEf of the driving energy after the low-pass filter process in which the high-frequency noise component is removed is calculated.

In step 50, the basic gain Kabb for the basic assist torque Tab is calculated based on the rate of change dDEf of the driving energy after the low-pass filter processing. In this case, when the rate of change dDEf is a positive value, the basic gain Kabb is calculated as a positive value (1 or less) that increases as the rate of change dDEf increases. On the other hand, when the rate of change dDEf is equal to or smaller than a preset negative reference value, the basic gain Kabb is calculated as a negative value (-1 or more) in which the absolute value increases as the rate of change dDEf decreases. Further, when the rate of change dDEf is larger than the negative reference value and equal to or smaller than 0, the basic gain Kabb is calculated so as to increase as the rate of change dDEf increases.

Also, the basic gain Kabb may be calculated to a constant value of 1 or less when the rate of change dDEf is a positive value. Further, the basic gain Kabb may be calculated to be a negative constant value of -1 or more when the rate of change dDEf is equal to or smaller than a preset negative reference value.

In step 60, the vehicle speed gain Kvab for the basic assist torque Tab is calculated based on the vehicle speed V as a positive value (not more than 1) that becomes smaller as the vehicle speed V becomes higher.

In step 70, the correction gain Kab for the basic assist torque Tab is calculated as the sum (Kabb · Kvab + 1) of the product of the basic gain Kabb and the vehicle speed gain Kvab and 1.

In step 80, the basic gain Kdab for the post-correction attenuation control amount Tda is calculated based on the rate of change dDEf of the driving energy after the low-pass filter process. In this case, when the rate of change dDEf is a positive value, the basic gain Kdab is calculated as a negative value (-1 or more) in which the absolute value increases as the rate of change dDEf increases. On the other hand, when the rate of change dDEf is equal to or smaller than a preset negative reference value, the basic gain Kdab is calculated as a positive value (1 or less) that increases with the decrease of the rate of change dDEf. Further, when the rate of change dDEf is larger than the negative reference value and equal to or smaller than 0, the basic gain Kdab is calculated so as to decrease as the rate of change dDEf increases.

In step 90, the vehicle speed gain Kvda for the post-correction attenuation control amount Tda is calculated as a positive value (1 or less) as the vehicle speed V becomes higher based on the vehicle speed V. [

In step 100, the correction gain Kda for the post-correction attenuation control amount Tda is calculated as the sum (Kdab · Kvda + 1) of the product of the basic gain Kdab and the vehicle speed gain Kvda and 1.

In step 110, the basic gain Kfab for the post-correction friction control amount Tfa is calculated based on the rate of change dDEf of the driving energy after the low-pass filter processing. In this case, when the rate of change dDEf is a positive value, the basic gain Kfab is calculated as a negative value (-1 or more) in which the absolute value increases as the rate of change dDEf increases. On the other hand, when the rate of change dDEf is equal to or smaller than a preset negative reference value, the basic gain Kfab is calculated as a positive value (1 or less) that increases with the decrease of the rate of change dDEf. Further, when the rate of change dDEf is larger than the negative reference value and equal to or smaller than 0, the basic gain Kfab is calculated so as to decrease as the rate of change dDEf increases.

In step 120, the vehicle speed gain Kvfa for the post-correction friction control amount Tfa is calculated based on the vehicle speed V as a positive value (1 or less) as the vehicle speed V becomes higher.

In step 130, the correction gain Kfa for the post-correction friction control amount Tfa is calculated as the sum (Kfab · Kvfa + 1) of the product of the basic gain Kfab and the vehicle speed gain Kvfa and 1.

The matters related to the arithmetic operations in the above-described steps 50 to 130 are described in the international publication of Patent Document 1 described above.

In step 140, the basic gain Krab for the feedback control amount Tra after correction is calculated based on the rate of change dDEf of the driving energy after the low-pass filter processing. In this case, when the rate of change dDEf is a positive value, the basic gain Krab is calculated as a negative value (-1 or more) in which the absolute value increases as the rate of change dDEf increases. On the other hand, when the rate of change dDEf is equal to or less than a predetermined negative reference value, the basic gain Krab is calculated as a positive value (1 or less) that increases with the decrease of the rate of change dDEf. Further, when the rate of change dDEf is larger than the negative reference value and equal to or smaller than 0, the basic gain Krab is calculated so as to decrease as the rate of change dDEf increases.

Further, the basic gains Kdab, Kfab, and Krab may be computed to a constant negative value of -1 or more when the rate of change dDEf is a positive value. Further, the basic gains Kdab, Kfab, and Krab may be calculated to a constant value of 1 or less when the rate of change dDEf is equal to or smaller than a preset negative reference value.

In step 150, the vehicle speed gain Kvra for the corrected return control amount Tra is calculated to be a positive constant value (1 or less) regardless of the vehicle speed V. [ Further, the vehicle speed gain Kvra may be calculated as a positive value (1 or less) that becomes slightly larger as the vehicle speed V becomes higher.

In step 160, the correction gain Kra for the corrected feedback control amount Tra is calculated as the product Krab · Kvra of the basic gain Krab and the vehicle speed gain Kvra.

The matters relating to the arithmetic operations in the above-mentioned steps 140 to 160 are described in Japanese Patent Application Laid-Open No. 2014-148178 filed by the applicant of the present application.

2, the correction gains Kab, Kda, Kfa, and Kra calculated in the correction gain calculation block 98 as described above are output to the multipliers 78, 82, 88, and 96, respectively. The output of the multiplier 78, that is, the signal indicative of the product of the basic assist torque Tab and the correction gain Kab, Tab · Kab is input to the adder 106.

A signal indicating the product Tda · Kda of the output of the multiplier 82, that is, the corrected attenuation control amount Tda and the correction gain Kda is also input to the adder 106. [ A signal indicating the sum (Tab · Kab + Tda · Kda) of the output of the adder 106, that is, the product Tab · Kab and the product Tda · Kda is input to the adder 108.

A signal indicating the product of the output of the multiplier 88, that is, the product of the corrected friction control amount Tfa and the correction gain Kfa, is also input to the adder 108. [ The signals representing the outputs of the adder 108, i.e., the sum of the products Tab Kab, Tda Kda and Tfa Kfa (Tab Kab + Tda Kda + Tfa Kfa) are input to the adder 110.

A signal indicating the product Tra · Kra of the output of the multiplier 96, that is, the correction return amount Tra after correction and the correction gain Kra is also input to the adder 110. The signals indicating the outputs of the adder 110, i.e., the sum of the products Tab Kab, Tda Kda, Tfa Kfa and Tra Kra (Tab Kab + Tda Kda + Tfa Kfa + Tra Kra) And is used as a signal indicative of a target assist torque Tat for controlling the steering device 12. [

As can be seen from the above description, the target assist torque Tat is calculated based on the basic assist torque (Tab Kab), the attenuation control amount Tda · Kda, the friction control amount Tfa · Kfa and the steering wheel 18 to the neutral position And a return control amount (Tra · Kra) for returning. The gains Kab, Kda, Kfa, and Kra of the control amounts are variably controlled based on the rate of change dDE of driving energy in accordance with the flowchart shown in Fig.

Particularly, in steps 20 and 30, the rate of change dDE of driving energy is calculated. In step 40, the rate of change dDEf of the driving energy in which the noise component of high frequency is removed by the low-pass filter processing is calculated. Then, the basic gains Kabb, Kdab, Kfab and Krab are calculated in steps 50, 80, 110 and 140 based on the rate of change dDEf of the driving energy after the low-pass filtering process, It is set variable depending on the size. Therefore, it is possible to appropriately change the amount of correction of each component (basic assist torque, damping control amount, friction control amount, and return control amount) of the target assist torque Tat as the adjustment force.

When the rate of change dDEf is large, that is, when the rate of change dDEf is large at a rate of increase in increase, the torque applied to the steering apparatus 16 from the road surface through the steered tire wheel is generally small. It is considered that the situation of the positive input given to the device 16 is satisfied.

According to the control of each gain performed in accordance with the flowchart shown in Fig. 3, the larger the change rate dDEf is, the larger the basic assist torque Tab, and the damping control amount Tda, the friction control amount Tfa and the return control amount Tra can be made smaller. Therefore, it is possible to reduce the steering resistance caused by the torque of the damping control, the torque of the friction control, and the return torque to the neutral position while assisting the steering of the driver, thereby making it easier to perform the steering operation by the driver.

Further, when the steering operation is performed in the direction of the neutral position by the driver in the state in which the control for returning the steering wheel 18 to the neutral position is performed by the return control amount Tra, the rate of change dDEf is determined to be positive, The return control amount Tra is reduced, and the assist torque is lowered. Therefore, in this situation, the return control amount Tra is not reduced, but the value is controlled to the same value as when the rate of change dDEf is negative or zero, thereby making it easy for the driver to perform steering in the neutral position direction.

On the other hand, when the change rate dDEf is negative and the absolute value is large, that is, when the absolute value is large at a rate of change of the change rate dDEf, the energy applied to the steering apparatus 16 by the driver's steering is 0 or a small value , It is considered that the situation of a large reverse input is inputted from the road surface to the steering apparatus 16 via the steered tire wheel.

According to the control of each gain performed in accordance with the flowchart shown in Fig. 3, as the change rate dDEf becomes negative and the absolute value becomes larger, the basic assist torque Tab is decreased and the damping control amount Tda, the friction control amount Tfa, can do. Therefore, the steering resistance can be increased without unnecessarily assisting the steering of the driver, so that the steering wheel 18 is driven to rotate due to the disturbance, and the steering stability can be improved.

Since the rate of change dDEf of the driving energy includes the term P0 related to the product of the steering angular speed and the differential value of the steering angular velocity, the steering wheel 18 is relatively largely changed even in the case where the steering wheel 18 is in the neutral region . Therefore, as compared with the determination based on the index value that does not include the term P0, in the situation where the steering wheel is in the neutral region, the change of the steering situation is determined early and thereby the basic assist torque Tab Can be controlled.

For example, FIG. 8 shows an example of the change in the specific force PS described in Patent Document 1, which is the sum of the rate of change dDE of driving energy and the term of P2 and the term of P2 for the situation in which the steering direction is reversed. It can be seen that the rate of change dDE changes from a negative value to a positive value at a point of time t1 earlier than a point of time t2 when the uniformity PS changes from a negative value to a positive value.

Fig. 9 shows an example of the change rate dDE of the driving energy and the variation rate PS described in Patent Document 1 with respect to a situation in which the hands-off is performed in the second half of the reciprocating steering. The uniformity PS is a negative value after the time point t3 when the hands are placed, whereas the rate of change dDE of the driving energy is a negative value immediately after the time point t3, but once it becomes a positive value, . In this phenomenon, the steering wheel 18 rotates immediately after the hands are placed and energy is given to the steering apparatus 16, whereby the rate of change dDE becomes once a positive value, but the rate of change and the dDE is again negative.

According to the first embodiment, it is possible to determine the rotational behavior of the steering wheel 18 by fluctuation over the positive / negative change rate dDE in a situation in which the hands are released in the second half of the reciprocating steering. Therefore, it is possible to appropriately control the increase / decrease of the basic assist torque Tab or the like in accordance with the rotational behavior of the steering wheel 18 in a situation where hand placement is performed without the necessity of judging hand placement.

Further, when the steering wheel 18 is rotated in the same direction by positive input and reverse input, the steering torque and its rate of change are only small. Therefore, this situation can not be determined depending on the unity PS. However, even in this situation, the steering wheel rotates, and therefore, the steering angle? Changes, and the steering angular velocity d? And its differential value dd? Change relatively large. Therefore, according to the rate of change dDE of the driving energy, even in the case where the positive input and the reverse input to the steering system are in phase, the increase / decrease control of the basic assist torque Tab or the like can be properly performed have. In addition, the above-mentioned operational effects are obtained similarly in the second embodiment described later.

[Second Embodiment]

4 is a block diagram of an assist torque calculation device 62 for calculating an assist torque Ta in a second embodiment of the steering system 10 for a vehicle according to the present invention. In Fig. 4, the same parts as those shown in Fig. 2 are denoted by the same reference numerals as those in Fig.

In the first embodiment, when the torque of the reverse input is large, it is possible to determine the reverse input and control the assist torque accordingly. However, even if the reverse input is generated, the reverse input can not be determined when the torque is small, and therefore, the assist torque can not be controlled in accordance with the reverse input.

In the second embodiment, the product dT · T of the steering torque T and the differential value dT thereof and the rate of change dDE of the driving energy as the index value Iin for determining whether the input to the steering apparatus 16 is the forward input or the reverse input, DTTDDE is calculated. When the input is the positive input, the product dT · T varies in phase with the rate of change dDE of the driving energy. However, when the input is the opposite input, the product dT · T changes inversely to the rate of change dDE of the driving energy. Therefore, the index value Iin is an index value indicating the ratio of the positive input and the reverse input to the total input to the steering apparatus 16, and the higher the ratio of the positive input to the total input, , And conversely, the higher the ratio of the reverse input to the total input, the more the absolute value of the index value Iin becomes negative.

For example, in a situation where the rate of change dDE of the driving energy changes as shown in the upper part of Fig. 10 and Fig. 11, Think about changing cases.

The region A is a region in which the rate of change dDE and the index value Iin are both positive, and the region B is a region in which the rate of change dDE is negative and the index value Iin is positive. The region C is a region in which the rate of change dDE is positive and the index value Iin is negative, and the region D is a negative region in which both the rate of change dDE and the index value Iin are negative.

The characteristics required of the steering apparatus 16 for the regions A to D are shown in Table 1 below. The area A is the area where the responsiveness of the steering should be emphasized, and the area B is the area where the stability of the steering should be important. The area C is an area where the degree of importance of responsiveness of the steering is to be reduced as compared with the case of the area A. [ The area C is an area where the degree of importance of response is to be reduced and corrected than in the case of area A so that the original response is obtained. The area D is an area where the responsiveness of the steering should be more emphasized than in the case of the area B. The required characteristics common to the areas A and B are steering characteristics that match the steering operation of the driver, and the demand characteristics common to the areas C and D are characteristics to reduce the burden on the driver due to the disturbance.

In this embodiment, the blocks other than the correction gain calculation block 98 of the assist torque calculation device 62 function in the same manner as the corresponding blocks in the first embodiment. 3, 5 and 6, the correction gain calculation block 98 calculates the correction gain Tda for the basic assist torque Tab, the post-correction attenuation control amount Tda, the post-correction friction control amount Tfa, and the corrected feedback control amount Tra Gain Kaba, Kdaa, Kfaa, and Kraa. The correction gains Kaba, Kdaa, Kfaa, and Kraa are output to the multipliers 78, 82, 86, and 96, respectively.

Steps 10 to 160 of the flowchart shown in Fig. 3 are executed in the same manner as in the first embodiment, and steps 210 to 420 of the flowcharts shown in Fig. 5 and Fig.

In step 210, a signal indicating the steering torque T detected by the steering torque sensor 54 is read, and in step 220, the differential value dT of the steering torque T is calculated.

In step 230, the product dT 占 의 of the steering torque T and the differential value dT thereof is calculated and the product dT 占 T is subjected to the low-pass filter processing, thereby calculating the product dT 占 후 after the low-

In step 240, the index value Iin of the input direction determination is calculated as the product dT · Tf · dDEf of the product dT · Tf after the low pass filter process and the rate of change dDEf of the driving energy after the low pass filter process.

In step 270, a basic gain Kiabb for the basic assist torque Tab is calculated based on the index value Iin of the input direction determination. In this case, when the index value Iin is a positive value, the basic gain Kiabb is calculated as a positive value (not more than 1) that increases with increase in the index value Iin. Conversely, when the index value Iin is equal to or smaller than a preset negative reference value, the basic gain Kiabb is calculated as a positive value (a value close to 0) in which the absolute value decreases in accordance with the decrease of the index value Iin. When the index value Iin is larger than the negative reference value and equal to or smaller than 0, the basic gain Kiabb is calculated so as to increase as the index value Iin increases.

Further, the basic gain Kiabb may be calculated to a constant value of 1 or less when the index value Iin is a positive value. The basic gain Kiabb may be calculated to a constant value close to 0 when the index value Iin is equal to or smaller than a preset negative reference value.

In step 280, the vehicle speed gain Kviab for the basic assist torque Tab is calculated based on the vehicle speed V as a positive value (not more than 1) that becomes smaller as the vehicle speed V becomes higher.

In step 290, the correction gain Kiab for the basic assist torque Tab is calculated as a product (Kiabb · Kviab) of the basic gain Kiabb and the vehicle speed gain Kviab.

In step 300, the corrected correction gain Kaba for the basic assist torque Tab is calculated as the sum (Kab + Kiab) of the correction gain Kab calculated in step 70 and the correction gain Kiab calculated in step 290. [

In step 310, a basic gain Kidab for the post-correction attenuation control amount Tda is calculated based on the input value determination index value Iin. In this case, when the index value Iin is a positive value, the basic gain Kidab is calculated as a positive value (a value close to 0) which decreases in accordance with the increase of the index value Iin. Conversely, when the index value Iin is equal to or smaller than a preset negative reference value, the basic gain Kidab is calculated as a positive value (1 or less) that increases in accordance with the decrease of the index value Iin. Further, when the index value Iin is larger than the negative reference value and smaller than or equal to 0, the basic gain Kidab is calculated so as to decrease as the index value Iin increases.

In step 320, the vehicle speed gain Kvida for the post-correction attenuation control amount Tda is calculated based on the vehicle speed V as a positive value (1 or less) as the vehicle speed V becomes higher.

In step 330, the correction gain Kida for the post-correction attenuation control amount Tda is calculated as the product (Kidab · Kvida) of the basic gain Kidab and the vehicle speed gain Kvida.

In step 340, the corrected correction gain Kdaa for the post-correction attenuation control amount Tda is calculated as the sum (Kda + Kida) of the correction gain Kda calculated in step 100 and the correction gain Kida calculated in step 330. [

In step 350, a basic gain Kifab for the post-correction friction control amount Tfaa is calculated based on the index value Iin of the input direction determination. In this case, when the index value Iin is a positive value, the basic gain Kifab is calculated as a positive value (a value close to 0) which decreases in accordance with the increase of the index value Iin. On the other hand, when the index value Iin is equal to or smaller than a predetermined negative reference value, the basic gain Kifab is calculated as a positive value (1 or less) that increases with the decrease of the index value Iin. Further, when the index value Iin is larger than the negative reference value and smaller than or equal to 0, the basic gain Kifab is calculated so as to decrease as the index value Iin increases.

In step 360, the vehicle speed gain Kvifa for the post-correction friction control amount Tfa is calculated based on the vehicle speed V as a positive value (1 or less) as the vehicle speed V increases.

In step 370, the correction gain Kifa for the post-correction friction control amount Tfa is calculated as a product (Kifab · Kvifa) of the basic gain Kifab and the vehicle speed gain Kvifa.

In step 380, the corrected correction gain Kfaa for the corrected friction control amount Tfa is calculated as the sum (Kfa + Kifa) of the correction gain Kfa calculated in step 130 and the correction gain Kifa calculated in step 370. [

In step 390, the basic gain Kirab for the feedback control amount Tra after correction is calculated based on the index value Iin of the input direction determination. In this case, when the index value Iin is a positive value, the basic gain Kirab is calculated as a positive value (a value close to 0) that decreases in accordance with the increase of the index value Iin. Conversely, when the index value Iin is equal to or lower than a preset negative reference value, the basic gain Kirab is calculated as a positive value (1 or less) that increases in accordance with the decrease of the index value Iin. Further, when the index value Iin is larger than the negative reference value and equal to or smaller than 0, the basic gain Kirab is calculated so as to decrease as the index value Iin increases.

In step 400, the vehicle speed gain Kvira for the post-correction return control amount Tra is calculated based on the vehicle speed V as a positive value (1 or less) as the vehicle speed V increases.

In step 410, the correction gain Kira for the corrected feedback control amount Tra is calculated as a product (Kirab · Kvira) of the basic gain Kirab and the vehicle speed gain Kvira.

In step 420, the corrected correction gain Kraa for the corrected feedback control amount Tra is calculated as the sum (Kra + Kira) of the correction gain Kra calculated in step 160 and the correction gain Kira calculated in step 410. [

Further, the basic gains Kidab, Kifab, and Kirab may be calculated to a constant value close to 0 when the index value Iin is a positive value. The basic gains Kidab, Kifab, and Kirab may be calculated to a constant value of 1 or less when the index value Iin is equal to or smaller than a preset negative reference value.

As can be seen from the above description, according to the second embodiment, the index value Iin for determining whether the input to the steering apparatus 16 is the forward input or the reverse input is calculated. The correction gains Kab, Kda, Kfa, and Kra are variably controlled not only in accordance with the rate of change dDEf of the driving energy, but also in accordance with the index value Iin, as in the first embodiment. Therefore, as shown in Table 1, the regions A to D can be discriminated according to the sign of the rate of change dDEf and the index value Iin, and the assist torque Ta can be controlled so as to have characteristics suitable for the region.

That is, according to the second embodiment, the magnitude of the basic assist torque or the like is controlled based on both the result of the determination of the input situation based on the rate of change dDEf of the driving energy and the result of the determination of the input situation based on the indicator value Iin can do. Therefore, compared to the case of the first embodiment in which the magnitude of the basic assist torque or the like is controlled based only on the determination result of the input situation based on the rate of change dDEf of the driving energy, the basic assist torque, Can be preferably controlled.

Particularly, in the region A, the magnitude of the basic assist torque (Tab Kab) is increased so as to obtain a characteristic in which the responsiveness of the steering by the driver is emphasized. In the region B, the attenuation control amount Tda · Kda and the friction control amount Tfa · Kfa (to be described later) are adjusted so that the degree of rotation of the steering wheel 18 due to the disturbance from the road surface is reduced, ), And the amount of the return control amount Tra · Kra become larger. In the area C, the increase amount of the magnitude of the basic assist torque Tab is reduced as compared with the case of the area A, so that the responsiveness of the steering by the driver is not excessive. Further, in the region D, the amount of increase in the magnitude of the damping control amount, the friction control amount, and the return control amount is increased as compared with the case of the region B, so that the characteristic in which the steering stability is more emphasized is obtained.

Further, according to the second embodiment, the index value Iin is calculated as the product dT · T · dDE of the product dT · T of the steering torque T and the differential value dT thereof and the rate of change dDE of the driving energy. Therefore, it is judged whether the input state of the energy to the steering system is the state of the positive input or the state of the reverse input by using the variation rate dDE of the steering system energy, the steering torque T provided for the calculation and the differential value dT of the steering torque can do. In addition, a special device for determining the input direction such as two torque sensors is unnecessary.

While the present invention has been described in detail with reference to the specific embodiments thereof, it will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, but various other embodiments are possible within the scope of the present invention will be.

For example, in each of the embodiments described above, the rate of change of the energy of the steering system is the differential value dDE of the driving energy DE, which is the energy of the steering system, but the difference (time derivative) of the driving energy DE .

In each of the above embodiments, the target assist torque Tat is calculated based on the basic assist torque Tab · Kab, the attenuation control amount Tda · Kda, the friction control amount Tfa · Kfa and the steering wheel 18 at the neutral position And a return control amount (Tra · Kra) for returning the control amount However, at least one of the damping control amount, the friction control amount, and the return control amount may be corrected so as not to be corrected in accordance with the change rate dDEf of the driving energy DE.

In the second embodiment described above, in order to determine whether the input to the steering apparatus 16 is a forward input or a reverse input, a product dT by the product of the steering torque T and its derivative value dT multiplied by the rate of change dDE of driving energy The index value Iin of the input direction determination is calculated by T · dDE. However, the determination of the input direction may be performed by other means.

For example, it is assumed that the relationship between the steering angle &thetas; in a certain vehicle speed and the control current Ic to the electric power steering apparatus 12 is a relationship represented by a solid line in Fig. 12, and the allowable range is indicated by a hatched area. When the relationship between the steering angle &thetas; and the control current Ic is within the range indicated by the hatched area, it is determined that the positive input (small reverse input) is present. When the relationship between the steering angle & , It may be judged that the situation is a reverse input.

Further, for example, two torque sensors are provided on the upper steering shaft 24 at positions spaced apart in the extending direction of the upper steering shaft 24, and the input to the steering device 16 is determined by the phase difference between the detected values of the two torque sensors. It may be determined whether the input is input or inverted input.

Further, the input direction is determined based on the product of the product of the steering torque T and the differential value dT and the rate of change of the uniformity PS by the product dT · T · dPS with dPS, with the rate of change of the uniformity PS described in Patent Document 1 being dPS . Also, since the index value Iin has a larger variation range than the product dT 占 d dPS, the index value Iin allows the input direction to be suitably adjusted even when the input direction changes frequently, particularly at the time of traveling on a bad road .

(EN) A steering control system for an electric power steering system comprising a steering wheel, a steering wheel, a steering wheel, a steering wheel, and a steering wheel. Each sensor, 54: torque sensor, 56: vehicle speed sensor, 62: assist torque calculating device

Claims (7)

The present invention is applied to a vehicle having a steering wheel operated by a driver, a steering wheel, and a steering device including a transmission device for transmitting a force and a displacement relating to steering between the steering wheel and the steered tire wheel, And a control device for controlling an adjusting force applied to the transmitting device by the adjusting force applying device, the steering assist device comprising:
A steering angle detecting device for detecting a steering angle,
A steering torque detecting apparatus for detecting a steering torque,
Wherein the control device acquires the steering angular speed, the differential value of the steering angular speed, and the differential value of the steering torque, and sets the steering angular velocity and the steering angular velocity Of the steering system based on the product of the product of the steering angular speed and the steering torque, and the product of the steering angle and the differential value of the steering torque, and calculates the change rate of the energy of the steering system based on the change rate of the energy of the steering system Thereby controlling the steering force. The method according to claim 1,
Wherein the control device is a movable member that constitutes the steering system and is characterized in that the product of at least the inertia yaw moment based on the mass of the movable member including at least the steering wheel and the differential value of the steering angular velocity and the steering angular velocity, And the derivative of the sum of the product of the steering angle and the differential value of the steering torque as the rate of change of the energy of the steering system. 3. The method according to claim 1 or 2,
The steering force is a steering assist force,
Wherein the control device increases the steering assist force when the rate of change of the energy of the steering system is a rate of change of the increase in the rate of change of the energy of the steering system is not the rate of change of the increase. 3. The method according to claim 1 or 2,
Wherein the adjusting force is at least one of a steering damping force and a steering frictional force,
Wherein the control device increases at least one of the steering damping force and the steering frictional force when the rate of change of the energy of the steering system is a rate of decrease of the energy of the steering system, Steering assist device. The method of claim 3,
Wherein the control device determines whether the input state of the energy to the steering system is a state of positive input based on a steering of the driver and a state of reverse input due to the steering wheel receiving a force from the road surface, Changing the amount of correction of the steering assist force so that the magnitude of the correction amount of the steering assist force in the state becomes smaller than the magnitude of the correction amount of the steering assist force in the state of the positive input, Car steering assistance device. 5. The method of claim 4,
Wherein the control device determines whether the input state of the energy to the steering system is a state of positive input based on a steering of the driver and a state of reverse input due to the steering wheel receiving a force from the road surface, So that the magnitude of at least one of the steering damping force and the steering frictional force in the situation is larger than the magnitude of at least one of the steering damping force and the steering frictional force in the forward input state , The steering damping force, and the steering friction force. The method according to claim 5 or 6,
Wherein the control device determines whether the input state of the energy to the steering system is a state of correct input based on the steering of the driver based on the product of the differential value of the steering torque and the steering torque and the rate of change of the energy of the steering system, And determines whether or not the steering wheel is in a state of reverse input by receiving force from the road surface.

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