JP5056351B2 - Electric power steering device - Google Patents

Description

  The present invention relates to a technical field of a vehicle steering control device (control device for an electric power steering device) for controlling, for example, an electric power steering device of a vehicle.

  An electric power steering apparatus that assists steering by driving an electric motor in accordance with a steering torque applied by a driver (occupant) steering operation in a vehicle such as an automobile and applying an assist assist torque to a steering mechanism including a front wheel. in use. In such an electric power steering device, as described in Patent Document 1, the electric power steering device is controlled so that the vehicle behavior or the characteristic of the steering angle with respect to the steering torque changes according to the frequency of the steering torque. There is a configuration. With this configuration, the vehicle behavior can be further stabilized while assisting the steering torque of the driver.

JP 2006-315632 A

  However, depending on the steering input of the driver, the above-described damping control will be worsened and the steering feeling will be worsened. Specifically, when phase compensation by the above-described EPS device is performed on a driver who performs a steering operation with a steering angle input (that is, when damping control is performed), the driver feels that the steering is heavy and the steering feeling is deteriorated. become.

  The present invention has been made in view of, for example, the above-described problems. For example, the driver's steering characteristics are grasped, and a compensation operation is performed on the steering assist force of the EPS device based on the characteristics, thereby enabling a wide range of drivers. It is an object of the present invention to provide a steering assist device for a vehicle that can give a good steering feeling to a vehicle.

  In order to solve the above-described problems, a vehicle steering control device according to the present invention includes a steering force applying unit that applies an auxiliary steering force based on a driver's steering input, and a steering torque and a steering angle that are detected by the steering input. A detecting means; a calculating means for calculating a steering characteristic of the driver based on the steering torque and the steering angle detected by the first detecting means; the steering characteristic; and a reference determined based on the steering torque and the steering angle. Calculating means for calculating a correlation with the steering characteristic; changing means for changing a mode of the compensating operation for compensating the auxiliary steering force based on the correlation calculated by the calculating means; and the compensating operation. Control means for controlling the steering force applying means so as to apply the auxiliary steering force.

  According to the vehicle steering control device of the present invention, the auxiliary steering force is applied to reduce the driver's steering burden according to the steering torque or the steering angle detected according to the driver's steering input by the operation of the steering force applying means. Is granted.

  Particularly in the present invention, when a driver's steering input is performed, the steering characteristics are calculated based on the steering torque and the steering angle at the steering input. The driver's steering characteristics typically include, for example, the frequency characteristics of the gain of the steering angle with respect to the steering torque and the frequency characteristics of the phase relationship between the steering torque and the steering angle. Of course, as other characteristics, for example, the frequency characteristic of the yaw rate of the vehicle with respect to the steering torque may be calculated as the steering characteristic.

  The calculated driver steering characteristic (that is, the actually inputted steering characteristic) is used for the calculation operation in the calculation means. The calculating means calculates a correlation (for example, a correlation value) between the steering characteristics of the driver and the reference steering characteristics determined based on the steering torque and the steering angle.

  Here, the reference steering characteristic is typically a characteristic that serves as a reference for determining whether the driver's steering input is a steering torque input or a steering angle input, and a reference for appropriately performing the determination. Any aspect can be taken.

  Thereafter, based on the correlation computed by the computing means, the compensation means compensates the auxiliary steering force (for example, damping control, steering return control, proportional value of the rear wheel lateral force and The aspect of damping control or the like according to the differential value is changed. For example, the mode of the compensation operation may be changed depending on whether or not the correlation indicates a predetermined relationship. In this case, as a matter of course, it is preferable that the change operation of the mode of the compensation operation based on the correlation is defined so that the driver's steering feeling can be improved. As a result, an auxiliary steering force that has been compensated in a manner appropriately corresponding to the steering characteristics of the driver is applied.

  Thus, after determining the driver's steering characteristics from the relationship between the steering angle of the driver's steering input and the frequency characteristics of the steering torque, the compensation operation for the auxiliary steering force applied by the steering force applying means based on the determination result is performed. The aspect can be changed. That is, a suitable compensation operation can be performed for the steering characteristics of each driver. As a result, it is possible to achieve steering assistance that gives a good impression on the steering characteristics of the individual drivers. Specifically, it is possible to achieve a good steering assist for both a driver that mainly inputs a steering angle and a driver that mainly inputs a steering torque.

  In one aspect of the vehicle steering control device according to the present invention, the calculation means depends on the first input characteristic indicating a characteristic of a steering input depending on the steering torque and the steering angle as the reference steering characteristic. A correlation with each of the second input characteristics indicating the characteristics of the steering input is calculated, and the changing means is relatively approximate to the steering characteristics among the first input characteristics and the second input characteristics, or The aspect of the compensation operation is changed so as to perform the compensation operation according to the input characteristics that are similar or coincident.

  According to this aspect, the calculating means typically appears as the first steering characteristic indicating the steering input characteristic depending on the steering torque as the reference steering characteristic (in other words, for example, when steering torque input is performed). Steering characteristics) and second input characteristics indicating the characteristics of the steering input depending on the steering angle (in other words, steering characteristics that typically appear when steering angle input is performed, for example) The correlation with the steering characteristics of the driver is calculated.

  That is, by the operation of the calculating means, the degree of approximation, similarity, or coincidence of the steering characteristics of the driver with respect to the two basic characteristics of the first input characteristic and the second input characteristic is calculated as a correlation.

  At this time, if the steering characteristic of the driver approximates, is similar to or coincides with the first input characteristic, a compensation operation according to the first input characteristic is performed. On the other hand, if the steering characteristic of the driver is close to, similar to or coincides with the second input characteristic, a compensation operation according to the second input characteristic is performed. As a result, it is possible to achieve steering assistance that gives a good impression on the steering characteristics of individual drivers.

  In the above description, the mode of the compensation operation is changed based on the correlation between the steering characteristic of the driver and the two input characteristics (that is, the first input characteristic and the second input characteristic). However, the mode of compensation operation may be changed based on the correlation between the driver's steering characteristics and three or more input characteristics.

  In another aspect of the vehicle steering control device of the present invention, the vehicle steering control device further includes recording means for recording the steering characteristics in the steering input of the driver, and the calculation means is recorded in the recording means. A correlation between the obtained steering characteristic and the reference steering characteristic is calculated.

  According to this aspect, the steering characteristic calculated when the driver's steering input is performed is recorded, and the calculation for obtaining the correlation between the recorded steering characteristic and the reference steering characteristic is performed. By this operation, it is possible to accumulate the driver steering characteristics recorded during driving of the vehicle, and by performing calculations based on the accumulated driver steering characteristics, the driver's steering characteristics are more impressive. Steering assistance can be achieved.

  In another aspect of the vehicle steering control apparatus according to the present invention, the calculating means calculates a frequency characteristic of the gain of the steering angle with respect to the steering torque as the steering characteristic.

  According to this aspect, when calculating the steering characteristic from the steering input of the driver, it is possible to calculate with high accuracy based on the steering frequency characteristic of the gain of the steering angle with respect to the steering torque at the steering input. As a result, it is possible to achieve a good impression of steering assistance corresponding to the steering characteristics of the driver with high accuracy.

  In another aspect of the vehicle steering control apparatus of the present invention, the calculation means calculates a frequency characteristic of a phase relationship between the steering torque and the steering angle as the steering characteristic.

  According to this aspect, when calculating the steering characteristic from the steering input of the driver, it is possible to calculate with high accuracy based on the steering frequency characteristic of the phase of the steering torque and the steering angle at the steering input. As a result, it is possible to achieve a good impression of steering assistance corresponding to the steering characteristics of the driver with high accuracy.

  In another aspect of the vehicle steering control device of the present invention, the calculation means calculates a correlation between the steering characteristic in the steering input of the driver and the preset reference steering characteristic.

  According to this aspect, for example, at the vehicle production stage, the reference steering characteristics are set in advance based on various conditions that can be read based on the vehicle characteristics (for example, vehicle weight, tire characteristics, or vehicle type) of the vehicle. Therefore, it is possible to set a reference steering characteristic that is suitable for the vehicle and is performed with high accuracy of compensation operation.

  Alternatively, the vehicle steering control device further includes a second detection unit that detects a vehicle characteristic based on a vehicle state, and an adjustment unit that adjusts the reference steering characteristic according to the vehicle characteristic. Calculates the correlation between the steering characteristics and the reference steering characteristics adjusted by the adjusting means.

  Here, the reference steering characteristic determined based on the steering torque and the steering angle changes at any time according to a change in vehicle characteristics such as the weight of the vehicle or the state of the tire, for example. On the other hand, if the calculation is always performed using the same input characteristics, the accuracy of the correlation deteriorates.

  According to this aspect, when the reference steering characteristic is changed due to the above-described factors, the changed vehicle characteristic is detected by the operation of the second detection unit, and the vehicle characteristic is determined by the operation of the adjustment unit. Thus, the reference steering characteristic is adjusted. As a result, even when the vehicle conditions change, the reference steering characteristics are adjusted following the changes to prevent the calculation accuracy of the steering characteristics from being reduced, and the steering assist that is good for the driver is achieved. I can do it.

  In addition, as a mode of adjusting the above-described reference steering characteristic, by setting a reference steering characteristic corresponding to various vehicle characteristics in advance, the vehicle characteristic detected by the second detection unit is approximated, similar, or coincident with the vehicle characteristic. Reference steering characteristics corresponding to existing vehicle characteristics may be applied, and for example, adjustment may be performed as needed based on a characteristic value indicating the detected vehicle characteristics.

  In another aspect of the vehicle steering control apparatus of the present invention, the recording means records the steering characteristic in the steering input of the driver when the acceleration of the vehicle is in a predetermined condition.

  According to this aspect, in a situation where the acceleration of the vehicle exceeds a predetermined range set in advance, the steering characteristic in the steering input of the driver is expected to deviate from the original steering characteristic of the driver. Does not record the steering characteristics. As a result, when recording the steering characteristics, it is possible to record the steering characteristics of the original driver with high accuracy.

  In another aspect of the vehicle steering control apparatus according to the present invention, the calculation means correlates the steering characteristic in the steering input of the driver and the reference steering characteristic when the acceleration of the vehicle is in a predetermined condition. Is calculated.

  According to this aspect, in a situation where the acceleration of the vehicle exceeds a predetermined range set in advance, the steering characteristic in the steering input of the driver is expected to deviate from the original steering characteristic of the driver. The calculation based on the steering characteristic is not performed. As a result, when performing calculations based on the steering characteristics, it is possible to perform calculations with high accuracy with respect to the original driver steering characteristics.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(1) Basic Configuration First, the basic configuration of the embodiment according to the vehicle steering control device of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the basic configuration of a vehicle adopting the embodiment of the vehicle steering control device of the present invention.

  As shown in FIG. 1, the vehicle 1 includes front wheels 5 and 6 and rear wheels 7 and 8. At least one of the front wheels and the rear wheels is driven by obtaining the driving force of the engine, and the front wheels are steered, whereby the vehicle 1 can travel in a desired direction.

  The front wheels 5 and 6, which are steered wheels, are steered by an electric power steering device 10 that is driven according to the steering wheel 11 being steered by a driver. Specifically, the electric power steering device 10 is, for example, a rack and pinion type electric power steering device, and includes a steering shaft 12 having one end connected to the steering wheel 11 and the other of the steering shaft 12. A rack and pinion mechanism 16 connected to the end of the steering wheel, a steering angle sensor 13 that detects a steering angle θ that is a rotation angle of the steering wheel 12, and a steering torque MT that is applied to the steering shaft 12 by the steering wheel 11 is detected. And an electric motor 15 that generates an auxiliary steering force that reduces the steering burden on the driver and applies the auxiliary steering force to the steering shaft 12 via a reduction gear (not shown).

  In such an electric power steering apparatus 10, the ECU 30 is based on the steering angle θ output from the steering angle sensor 13, the steering torque MT output from the torque sensor 14, and the vehicle speed V output from the vehicle speed sensor 41. A target assist torque T that is a torque generated by the electric motor 15 is calculated.

  The target assist torque T is output from the ECU 30 to the electric motor 15, and the electric motor 15 is driven by supplying a current corresponding to the target assist torque T to the electric motor 15. As a result, a steering assist force is applied from the electric motor 15 to the steering shaft 12, and as a result, the driver's steering burden is reduced. In addition, the rack and pinion mechanism 16 converts the force in the rotational direction of the steering shaft 12 into the force in the reciprocating direction of the rack bar 17. Both ends of the rack bar 17 are connected to the front wheels 5 and 6 through tie rods 18, and the directions of the front wheels 5 and 6 change according to the reciprocating motion of the rack bar 17.

  Furthermore, in the embodiment according to the vehicle steering control device of the present invention, the ECU 30 outputs the steering angle θ output from the steering angle sensor 13 and the steering torque MT output from the torque sensor 14 by the ECU 30 every time the driver inputs steering. Based on this, the steering characteristic of the steering input is calculated. Further, the ECU 30 calculates a correlation between the steering characteristics of the driver and the reference steering characteristics based on the steering torque and the steering angle. Based on the calculated correlation, the ECU 30 compensates the steering assist force applied based on the target assist torque AT described above (for example, a damping control operation, a steering return control operation, or a front wheel In addition, the driving of the electric motor is controlled so as to perform these compensation operations while appropriately determining the mode of the control operation for further applying a correction torque based on the lateral force of at least one of the rear wheels.

  Further, the ECU 30 confirms the state of the vehicle based on the vehicle weight M output from the weight sensor 42, the lateral G output from the lateral G sensor 43, and the yaw rate γ output from the yaw rate sensor 44. When a change occurs in the state of the vehicle, the above-described reference steering characteristics are adjusted based on the change.

(2) Operation Principle Next, the operation of the electric power steering apparatus 10 according to the present embodiment will be described in more detail with reference to FIG. FIG. 2 is a flowchart conceptually showing the entire operation of the electric power steering apparatus 10.

  As shown in FIG. 2, the basic assist torque AT that is the base of the auxiliary steering force to be applied from the electric motor 15 is calculated by the operation of the ECU 30 (step S <b> 10). When calculating the basic assist torque AT, first, the ECU 30 reads various signals (for example, the vehicle speed V, the steering torque MT, etc.) necessary for calculating the basic assist torque AT. Subsequently, the basic assist torque AT is calculated based on the read various signals.

  Here, a specific example of the calculation operation of the basic assist torque AT will be described with reference to FIG. FIG. 3 is a graph showing the basic assist torque AT.

  As shown in FIG. 3, the basic assist torque AT may be calculated based on, for example, a graph (or mapping) showing a relationship between the steering torque MT and the basic assist torque AT. More specifically, in order to secure play of the steering wheel 11, the basic assist torque is calculated as 0 when the steering torque MT is relatively small. When the steering torque MT becomes a certain level, a larger basic assist torque AT is calculated as the steering torque MT increases. When the steering torque MT is larger than a predetermined value, a constant basic assist torque AT that does not vary depending on the magnitude of the steering torque MT is calculated. At this time, the basic assist torque AT may be reduced as the vehicle speed V increases.

  Needless to say, the calculation operation of the basic assist torque AT illustrated here is merely an example, and may be calculated using another method.

  Returning to FIG. 2, subsequently, the vehicle acceleration A is acquired by the operation of the ECU 30 (step S11). As a specific example, it is based on the operation of receiving the input of the vehicle speed V detected by the operation of the vehicle speed sensor 41 and calculating the ECU 30.

  Subsequently, it is determined by the operation of the ECU 30 whether or not the vehicle acceleration A acquired in step S11 is within a predetermined range (step S12). When the vehicle acceleration A exceeds the predetermined range (step S12: No), the compensation control in this embodiment is not performed, and the acquisition and determination of the vehicle acceleration A are continued.

  When the vehicle acceleration A is within the predetermined range (step S12: Yes), the steering torque MT and the steering angle θ are subsequently acquired by the operation of the ECU 30 (step S13). Specifically, the steering torque MT detected by the torque sensor 14 and the steering angle θ detected by the steering angle sensor 13 are output to the ECU 30.

  Subsequently, the steering characteristics of the driver's steering input are calculated by the operation of the ECU 30 based on the steering torque MT and the steering angle θ acquired in step S13 (step S14). Here, examples of the steering characteristic include a steering frequency characteristic of the gain of the steering angle θ with respect to the steering torque MT at the steering input of the driver, and a steering frequency characteristic of the phase relationship between the steering torque MT and the steering angle θ.

  Further, by the operation of the ECU 30, the correlation between the steering characteristic in the steering input of the driver calculated in step S14 (hereinafter referred to as “driver steering characteristic” as appropriate) and a preset reference input characteristic is calculated ( Step S15). Here, in order to express the correlation, an appropriate numerical value may be calculated.

  Here, the calculation of the correlation between the driver steering characteristic and the reference steering characteristic will be described with reference to FIGS. Here, the value MT-Ratio is used to represent the correlation.

  FIGS. 4A and 4B show a specific example (broken line portion) of the driver steering characteristic (solid line portion) and the reference steering characteristic. The horizontal axis represents the steering frequency and the vertical axis represents the steering torque MT. This is represented on the graph with the gain of the steering angle θ (FIG. 4A) or the phase relationship between the steering torque MT and the steering angle θ (FIG. 4B).

  In calculating the correlation between the driver steering characteristic and the reference steering characteristic, in the simplest form, the driver's steering input is steered depending on whether the driver steering characteristic is above or below the reference steering characteristic. It is determined whether the torque input or the steering angle input. For example, in FIG. 4A, when there is a driver steering characteristic above the reference steering characteristic (that is, when the driver has a higher gain than the reference steering characteristic), the driver's steering input is the steering angle input and below. In this case (that is, when the gain is lower than the reference steering characteristic), it is determined that the driver's steering input is a steering torque input.

  Of course, it goes without saying that the correlation between the driver steering characteristic and the reference steering characteristic may be calculated based on other numerical processes.

  FIGS. 5A and 5B are another specific examples of characteristic diagrams showing the driver steering characteristic (solid line part) and the reference steering characteristic (broken line part). In such an aspect, the integrated value of the difference obtained by subtracting the reference steering characteristic from the driver steering characteristic in the frequency band where the driver steering characteristic is located above the reference steering characteristic (that is, the area of FIG. 5A), and the reference steering characteristic The steering input of the driver is the steering torque input based on the ratio of the difference value obtained by subtracting the reference steering characteristic from the driver steering characteristic in the frequency band where the driver steering characteristic is located below (that is, the area in FIG. 5B). Or a steering angle input is determined. For example, when the ratio in the frequency band where the driver steering characteristic is located above the reference steering characteristic is large, it is determined that the steering input of the driver is a steering angle input.

  Of course, it goes without saying that the correlation between the driver steering characteristic and the reference steering characteristic may be calculated based on the result obtained by performing other numerical processing on the integral value.

  FIGS. 6A and 6B are characteristic diagrams showing the correlation between the driver steering characteristic and the reference steering characteristic. In this aspect, the reference steering characteristic is composed of two curves, a steering angle input characteristic that typically appears when the steering angle is input, and a steering torque input characteristic that typically appears when the steering torque is input. .

  In this aspect, in calculating the correlation between the driver steering characteristic and the reference steering characteristic, for example, the integrated value of the difference between the characteristics at a predetermined frequency (or frequency band), that is, FIG. 6A and FIG. An area of a figure surrounded by a curve representing each characteristic of the graph in (b) and a straight line representing a predetermined frequency (or at least two straight lines representing a threshold of a predetermined frequency band) is used. More specifically, the curve of the steering angle input characteristic, the curve of the steering torque input characteristic, the curve of the driver's steering characteristic and the steering torque input characteristic in the area of the figure surrounded by the straight line indicating the predetermined frequency, and the predetermined The ratio of the area of the figure surrounded by the straight line indicating the frequency (or at least two straight lines indicating the threshold of the predetermined frequency band) is calculated as MT-Ratio which is an example of one index indicating the correlation. The In this case, the closer the driver steering characteristic is to the steering torque input characteristic, the closer MT_Ratio approaches “1”. On the other hand, the closer the driver steering characteristic is to the steering angle input characteristic, the closer MT_Ratio approaches “0”.

  Further, MT_Ratio (hereinafter referred to as “MT_Ratio_gain”) calculated from the frequency characteristic of the gain of the steering angle θ in the steering torque MT shown in FIG. 6A may be used as MT-Ratio representing the correlation. . Alternatively, MT_Ratio (hereinafter referred to as “MT_Ratio_phase”) calculated from the frequency characteristics of the phase relationship between the steering torque MT and the steering angle θ shown in FIG. 6B may be used as MT-Ratio representing the correlation. Good. Alternatively, an overall MT_Ratio (hereinafter referred to as “MT_Ratio_Total”) derived from both of the calculation results (that is, each of MT_Ratio_gain and MT_Ratio_phase) may be used. In this case, if A and B (where A + B = 1) are predetermined coefficients, MT_Ratio_Total may be calculated according to the following formula: MT_Ratio_Total = A × MT_Ratio_gain + B × MT_Ratio_phase.

  Furthermore, the MT-Ratio is a continuous numerical value indicating how the driver steering characteristic is related to the steering angle input characteristic and the steering torque input characteristic as described above. However, the actual driver steering characteristic directly indicates the model characteristic determined to be the closest among two or more preset model characteristics (for example, the above-described steering torque input characteristic and steering angle input characteristic). It may be a digital value. For example, when MT_Ratio calculated from the graphs shown in FIGS. 6A and 6B is 0.5 or more, it is considered that the driver steering characteristic is closer to the steering torque input characteristic than the steering angle input characteristic. It is done. Therefore, in this case, it may be calculated as MT_Ratio = 1. For example, when MT_Ratio calculated from the graphs shown in FIGS. 6A and 6B is less than 0.5, it is considered that the driver steering characteristic is closer to the steering angle input characteristic than the steering torque input characteristic. It is done. Therefore, in this case, calculation may be performed with MT_Ratio = 0.

  It should be noted that the operation of calculating the correlation of the steering characteristics exemplified here is merely an example, and it goes without saying that the calculation may be performed using other methods.

  Returning to FIG. 2 again, based on the correlation of the steering characteristics calculated in step S15 (that is, MT_Ratio in this embodiment), the ECU 30 changes the mode of the compensation operation for compensating the basic assist torque AT, The operation of the electric motor 15 is controlled so as to achieve the compensation operation based on the change (step S16). For example, when the driver steering characteristic matches or approximates the steering torque input characteristic (for example, when MT_Ratio≈1), or when the driver steering characteristic is closer to the steering torque input characteristic than the steering angle input characteristic (for example, MT_Ratio ≧ In the case of 0.5), it is preferable to change the mode of the compensation operation so that the compensation operation is performed in a mode suitable for the steering torque input characteristics. On the other hand, when the driver steering characteristic matches or approximates the steering angle input characteristic (for example, when MT_Ratio≈0), or when the driver steering characteristic is closer to the steering angle input characteristic than the steering torque input characteristic (for example, MT_Ratio) In the case of <0.5), it is preferable to change the mode of the compensation operation so that the compensation operation is performed in a mode suitable for the steering angle input characteristics.

  Alternatively, instead of changing the mode of the compensation operation alternatively, the mode of the compensation operation may be changed in an analog manner based on the value of MT_Ratio. For example, numerical values such as various parameters specifying the compensation operation may be appropriately adjusted based on the value of MT_Ratio. This is particularly effective when MT_Ratio takes a value other than 0 or 1. For example, when the driver steering characteristic is close to the steering torque input characteristic but not far from the steering angle input characteristic (for example, when the value of MT_Ratio = 0.5 to about 0.75), the steering torque input characteristic is It is preferable to change the mode of the compensation operation so that the compensation operation is performed in a mode that is suitably adapted to the steering angle input characteristics. Similarly, for example, when the driver steering characteristic is close to the steering angle input characteristic but not far from the steering torque input characteristic (for example, when the value of MT_Ratio = 0.25 to about 0.5), the steering angle It is preferable to change the mode of the compensation operation so that the compensation operation is performed in a mode that suitably matches the input characteristics but also appropriately matches the steering torque input characteristics.

  In addition to the steering assist operation for applying the basic assist torque AT calculated by the vehicle speed V and the steering torque MT, the driver steering characteristics are calculated from the steering torque MT and the steering angle θ in the driver's steering input by the above-described operation, By performing an operation of changing the steering assist compensation based on the correlation between the driver steering characteristic and a preset reference steering characteristic, the auxiliary steering force that has been compensated in a manner appropriately corresponding to the driver steering characteristic is obtained. Is granted. Therefore, a suitable compensation operation can be performed for each driver steering characteristic. As a result, it is possible to achieve a good steering assistance for the steering input of each driver. Specifically, it is possible to achieve favorable steering assistance (in other words, steering assistance that does not cause a sense of incongruity) for both the driver that mainly inputs the steering angle and the driver that mainly inputs the steering torque.

  Further, during the above-described operation, the ECU 30 may be set to record the steering characteristic (that is, the driver steering characteristic) in the steering input of the driver in the memory 31 at an arbitrarily set timing. Along with this operation, the ECU 30 may be set to read the steering characteristics recorded in the memory 31 together with the detected steering characteristics of the driver's steering input and use them for the calculation in calculating the steering characteristics.

  According to this operation, the driver steering characteristics can be accumulated and used for calculating the correlation to be based on when the compensation operation is changed. For this reason, for example, even when the driver performs a steering input that deviates from the accumulated conventional (ie, original) steering characteristics, not only the steering characteristics in the steering input but also the accumulated conventional steering characteristics Compensation operation based on the included correlation is performed. As a result, even in the case described above, the steering feeling suddenly changes greatly for the driver, but the situation can be avoided, and the usual and good steering assistance can be achieved.

(First modified operation example)
Next, a first modified operation example of the vehicle steering control device according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart showing in more detail the operation when the electric power steering apparatus 10 in the vehicle steering control apparatus according to this modified operation example performs the compensation control (step S16) in the flowchart of FIG. . FIG. 8 is a graph showing a gain coefficient related to the gain of the compensation control based on the correlation of the steering characteristics in the compensation control.

  When the correlation between the driver steering characteristic and the reference input characteristic is calculated and compensation control is performed based on the correlation, in the first modified operation example, the gain coefficient relating to the gain of compensation control based on the correlation is calculated. Calculated. The gain coefficient does not necessarily match the value indicating the correlation as in the above-described MT-Ratio, and may be a coefficient indicating the amount of compensation control based on the correlation.

  In the operation of the first modified operation example, after the correlation between the driver steering characteristic and the reference steering characteristic in the operation example according to the present invention is calculated (step S15 in FIG. 2), compensation control is performed based on the correlation. A target gain coefficient indicating the compensation gain is calculated (step S20).

  At the same time, the current gain coefficient used for the current compensation control is calculated (step S21). Next, the ECU 30 compares the target gain coefficient with the current gain coefficient (step S22). In this comparison, the difference between the target gain coefficient and the current gain coefficient is noted, and when the difference is an amount within a certain range (step S22: No), the current gain coefficient is the same as the value of the target gain coefficient. Then, a compensation operation based on the updated current gain coefficient value is performed (step S25).

  On the other hand, when the difference between the target gain coefficient and the current gain coefficient is a certain amount or more (step S22: Yes), as shown in FIG. 8, the change of the current gain coefficient with respect to time keeps a constant slope. The current gain coefficient is brought close to the target gain coefficient value (step S23), and then a compensation operation based on the updated current gain coefficient value is performed similarly (step S25).

  For example, when the driver changes in the same vehicle equipped with the vehicle steering control device according to this modified operation example by the above-described operation, the old driver steering characteristic seems to have a certain difference from the new driver steering characteristic. Even in such a case, the steering control can be performed so as to give a sense of incongruity by not gradually changing the gain of the compensation operation but gradually adjusting the gain.

(Second modified operation example)
Next, with reference to FIG. 9, a second modified operation example in which the reference input characteristic resetting operation resulting from the change of the vehicle characteristic in the vehicle steering control device according to the present invention will be described. FIG. 9 is a conceptual flowchart when the electric power steering apparatus 10 in the vehicle steering control apparatus according to this modified operation example performs the above-described operation.

  In order to perform compensation control based on the driver steering characteristic, in the second modified operation example, the driver steering characteristic and a preset reference input characteristic (that is, the steering torque input characteristic and the steering angle input characteristic, or the first input) And the second input characteristic) are calculated (step S15 in FIG. 2), and the mode of compensation operation is changed based on the correlation (step S16 in FIG. 2).

  However, the reference input characteristics described above change due to changes in vehicle characteristics such as changes in vehicle weight and tires.

  In the second modified operation example, the vehicle characteristics are acquired by the operation of the ECU 30 (step S30). More specifically, each vehicle characteristic related to the reference input characteristic detected by the operation of the weight sensor 42 and other various sensors (not shown) is received and acquired by the ECU 30.

  Subsequently, the reference input characteristic is reset based on the acquired vehicle characteristic (step S31). Here, the resetting of the reference input characteristics may be performed by identifying a preset vehicle model as a reference from the detected vehicle characteristics, and setting the reference input characteristics set in the vehicle model. Alternatively, it may be calculated based on a value indicating the detected vehicle characteristic.

  Next, the reset reference input characteristic is used for calculation of the correlation with the driver steering characteristic (step S15), and the compensation operation is changed based on the correlation (step S16).

  According to the operation of the second modified operation example, the reference input characteristic is changed even when the vehicle characteristic changes due to, for example, a change in the number of passengers, loading weight, or tire of the vehicle. Although the accuracy of the compensation control derived from the correlation is lowered, the situation can be avoided and compensation control corresponding to the vehicle characteristics after the change can be achieved.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and vehicle steering control with such changes is possible. The apparatus is also included in the technical scope of the present invention.

It is a schematic block diagram which shows notionally the basic composition of the embodiment concerning the steering control device for vehicles of the present invention. It is a flowchart which shows notionally the whole operation | movement of embodiment which concerns on the steering control apparatus for vehicles of this invention. It is a graph which shows a basic assist torque. It is a characteristic view which shows the frequency characteristic of a torque and a phase in a driver steering characteristic and a reference | standard steering characteristic. FIG. 6 is a deformation characteristic diagram showing frequency characteristics of torque and phase in driver steering characteristics and reference steering characteristics. FIG. 7 is a characteristic diagram showing frequency characteristics of torque and phase in driver steering characteristics and steering torque input characteristics and steering angle input characteristics. It is a flowchart which shows notionally the compensation control operation | movement of the steering control apparatus for vehicles which concerns on a 1st modification operation example. It is a graph which shows the gain coefficient which concerns on the gain of compensation control. It is a flowchart which shows notionally the reset operation | movement of the input characteristic resulting from the change of the vehicle characteristic of the steering control apparatus for vehicles which concerns on a 2nd modified operation example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 5, 6 Front wheel 7, 8 Rear wheel 10 Electric power steering apparatus 11 Steering wheel 13 Steering angle sensor 14 Torque sensor 15 Electric motor 30 ECU
31 Memory 41 Vehicle speed sensor 42 Weight sensor 43 Lateral G sensor 44 Yaw rate sensor

Claims (8)

Steering force applying means for applying an auxiliary steering force based on a driver's steering input;
First detection means for detecting a steering torque and a steering angle in the steering input;
Calculating means for calculating a steering characteristic of the driver based on a steering torque and a steering angle detected by the first detecting means;
Arithmetic means for calculating a correlation between the steering characteristic and a reference steering characteristic determined based on the steering torque and the steering angle;
Changing means for changing the mode of compensation operation for compensating the auxiliary steering force based on the correlation calculated by the calculating means;
Control means for controlling the steering force applying means to apply the auxiliary steering force subjected to the compensation operation , and
The calculation means includes a first input characteristic indicating a steering input characteristic depending on the steering torque and a second input characteristic indicating a steering input characteristic depending on the steering angle as the reference steering characteristic. The correlation of
The changing means performs the compensation operation according to an input characteristic that is relatively close to, similar to, or coincident with the steering characteristic among the first input characteristic and the second input characteristic. the vehicle steering control apparatus characterized that you change the mode of operation. The vehicle steering control device further includes recording means for recording the steering characteristic in the steering input of the driver,
The vehicle steering control device according to claim 1 , wherein the calculating unit calculates a correlation between the steering characteristic recorded in the recording unit and the reference steering characteristic. The calculating means, the frequency characteristics of the gain of the steering angle relative to the steering torque, vehicle steering control device according to claim 1 or 2, characterized in that calculated as the steering characteristic. The calculating means, the steering torque and the frequency characteristic of the phase relationship of the steering angle, the vehicle steering control device according to claim 1, wherein the calculating to any one of 3 as the steering characteristic. Said calculation means, said steering characteristic in the steering input of the driver, preset vehicle of any one of claims 1 4, characterized by calculating the correlation between said reference steering characteristic Steering control device. The vehicle steering control device comprises:
Second detection means for detecting vehicle characteristics based on the state of the vehicle;
Adjusting means for adjusting the reference steering characteristic according to the vehicle characteristic; and the calculating means calculates a correlation between the steering characteristic and the reference steering characteristic adjusted by the adjusting means. The vehicle steering control device according to claim 5 . The vehicle steering control device according to claim 2 , wherein the recording unit records the steering characteristic in the steering input of the driver when the acceleration of the vehicle is in a predetermined condition. It said calculating means, when the acceleration of the vehicle is in a predetermined condition, and the steering characteristics in a steering input of the driver, of claims 1 to 5, characterized in that for calculating the correlation between said reference steering characteristic The vehicle steering control device according to any one of the preceding claims.

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