JP7316136B2 - electric power steering device - Google Patents

Description

The present invention relates to an electric power steering system.

Patent Document 1 discloses an electric power unit that includes a steering portion that steers wheels, an electric portion that applies drive torque to the steering portion via a transmission mechanism, and a control portion that controls driving of the electric portion. A steering device is disclosed.

JP 2013-159165 A

In the electric power steering apparatus described in Patent Document 1, a driving torque is applied from an electric part to a steering part via a transmission mechanism in which backlash exists, such as a speed reduction mechanism or a rack and pinion mechanism. Therefore, when the steering direction is opposite to the previous steering direction, the driving torque of the electric part is not applied to the wheels until the backlash existing on the path for transmitting the driving torque of the electric part to the wheels is reduced. There is a delay between steering and when the wheels begin to turn.

On the other hand, when the steering direction is the same as the previous steering direction, the backlash on the path for transmitting the driving torque of the electric part to the wheels is reduced, so the wheels respond to steering. steer with good responsiveness.

Therefore, for example, when the vehicle is steered in either the left or right direction from a state in which steering is not being performed and the vehicle is traveling straight ahead, the wheels are turned after the steering is performed depending on whether or not backlash exists on the torque transmission path in the steering direction. Since the time required to start steering changes, the operability of the vehicle may deteriorate.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the operability of a vehicle equipped with an electric power steering system.

According to the present invention, an electric power steering device acquires information on an electric unit that generates a drive torque for steering wheels, a control unit that controls the driving of the electric unit, and information on the own vehicle and a preceding vehicle running in front of the own vehicle. and an information acquisition unit, wherein the control unit predicts the steering state of the own vehicle based on the information of the preceding vehicle acquired by the information acquisition unit, and based on the prediction result of the steering prediction unit, the wheels A pressing control unit that generates a pressing torque in the electric unit that reduces the play on the path that transmits the driving torque to the steering wheel, and determines that the pressing control unit does not need to perform control when the steering wheel is being operated by the driver. and a control execution determination unit that determines that execution of control by the pressing control unit is necessary when the steering wheel is not operated by the driver.

According to the present invention, the electric drive unit generates a pressing torque that closes the gap on the path for transmitting the driving torque to the wheels according to the steering state of the own vehicle predicted based on the information of the preceding vehicle. In this way, the slack on the torque transmission path is reduced before steering is performed, so that the wheels are steered stably with good responsiveness in response to steering.

Moreover, the present invention is characterized in that the magnitude of the pressing torque is set to a magnitude that does not allow the wheels to be steered.

In this invention, the magnitude of the pressing torque is set to a magnitude that does not allow the wheels to be steered. Therefore, the slack on the torque transmission path can be reliably reduced before steering is performed without affecting the operation of the vehicle. As a result, the wheels are stably steered with good responsiveness in response to steering, and the operability of the vehicle equipped with the electric power steering device can be improved.

Further, according to the present invention, the electric power steering apparatus further includes a steering state detector for detecting the steering state of the wheels, and the pressing torque is set to a magnitude that does not change the detection value of the steering state detector. It is characterized by being set.

In this invention, the magnitude of the pressing torque is set to a magnitude that does not change the detection value of the steering state detector. That is, the pressing torque is set to a magnitude that does not allow the wheels to be steered. Therefore, the slack in the torque transmission path can be closed before steering is performed without affecting the operation of the vehicle. As a result, the wheels are stably steered with good responsiveness in response to steering, and the operability of the vehicle equipped with the electric power steering device can be improved.

Further, according to the present invention, the steering prediction unit predicts the predicted steering direction of the own vehicle based on the information about the steering direction of the preceding vehicle acquired by the information acquisition unit, and the pressing control unit controls the pressing torque generated by the electric unit. is controlled to act in the predicted steering direction predicted by the steering prediction section.

In this invention, the pressing torque generated by the electric section acts in the predicted steering direction predicted by the steering prediction section. By applying pressing torque so as to reduce the leeway on the torque transmission path in the predicted steering direction of the own vehicle thus predicted, the leeway on the torque transmission path is reduced before steering is performed. can be done. As a result, the wheels are stably steered with good responsiveness in response to steering, and the operability of the vehicle equipped with the electric power steering device can be improved.

Further, according to the present invention, the steering predicting unit, based on the information about the steering point of the preceding vehicle acquired by the information acquiring unit, performs steering of the own vehicle until the vehicle reaches the predicted steering point. predicts at least one of the predicted arrival times, and the pressing control unit generates pressing torque in the electric unit when the distance of the vehicle to the predicted steering point is less than a predetermined distance or when the predicted arrival time is less than a predetermined time. It is characterized by

In the present invention, the electric portion generates pressing torque when the distance of the vehicle to the predicted steering point is less than a predetermined distance or when the predicted arrival time until the vehicle reaches the predicted steering point is less than a predetermined time. In this way, by causing the electric unit to generate pressing torque when the host vehicle approaches the predicted steering point, it is possible to close the slack in the torque transmission path immediately before the steering is performed. As a result, the wheels are stably steered with good responsiveness in response to steering, and the operability of the vehicle equipped with the electric power steering device can be improved.

Further, in the present invention, the control unit includes an inter-vehicle distance calculation unit that calculates the inter-vehicle distance between the own vehicle and the preceding vehicle based on the information of the own vehicle and the preceding vehicle acquired by the information acquisition unit, and the vehicle speed of the own vehicle. and a reference inter-vehicle distance calculator for calculating the reference inter-vehicle distance, and the steering predictor predicts the steering state of the own vehicle when the inter-vehicle distance is equal to or greater than the reference inter-vehicle distance.

In this invention, the steering state of the own vehicle is predicted by the steering prediction unit when the inter-vehicle distance is greater than or equal to the reference inter-vehicle distance. When the vehicle-to-vehicle distance is relatively short in this way, the power consumption of the electric drive unit can be reduced by suppressing the current supply to the electric drive unit without predicting the steering state of the host vehicle.

Further, according to the present invention, the information acquisition unit acquires information of a plurality of preceding vehicles, and the steering prediction unit predicts the steering state of the own vehicle based on the steering information of the plurality of preceding vehicles acquired by the information acquisition unit. is characterized by predicting

Further, the present invention is characterized in that the steering prediction unit predicts that when the steering directions of a plurality of preceding vehicles are the same at a specific point, the own vehicle will also be steered in the same direction at the specific point. .

In these inventions, the steering state of the host vehicle is predicted based on the steering information of a plurality of preceding vehicles. By predicting the steering state of the own vehicle based on the steering information of a plurality of preceding vehicles in this manner, the steering state of the own vehicle can be accurately predicted.

According to the present invention, it is possible to improve the operability of a vehicle equipped with an electric power steering device.

1 is a configuration diagram of an electric power steering device according to an embodiment of the present invention; FIG. 1 is a block diagram of an electric power steering device according to an embodiment of the invention; FIG. FIG. 4 is a first explanatory diagram for explaining a processing procedure when reducing the slack on the torque transmission path in the electric power steering device according to the embodiment of the present invention; FIG. 5 is a second explanatory diagram for explaining a processing procedure when reducing the slack on the torque transmission path in the electric power steering device according to the embodiment of the present invention; FIG. 5 is a third explanatory diagram for explaining a processing procedure when reducing the slack on the torque transmission path in the electric power steering device according to the embodiment of the invention; 4 is a flow chart showing a processing procedure when reducing the slack on the torque transmission path in the electric power steering system according to the embodiment of the invention;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

An electric power steering device 100 (hereinafter referred to as "steering device 100") according to an embodiment of the present invention will be described with reference to FIG. The steering device 100 is mounted on a vehicle and assists the steering force applied to the steering wheel 10 by the driver to steer the wheels 1 .

As shown in FIG. 1, the steering device 100 includes a steering shaft 20 that rotates by steering torque input from a steering wheel 10, and a rack shaft that serves as a steering portion that steers wheels 1 as the steering shaft 20 rotates. 30 and.

The steering shaft 20 includes an input shaft 21 that rotates as the driver operates the steering wheel 10, an output shaft 22 that displaces the rack shaft 30, and a torsion bar that connects the input shaft 21 and the output shaft 22. 23 and .

The rack shaft 30 is a shaft-shaped member that extends in the left-right direction of the vehicle and is connected to the wheel 1 via tie rods 41 and knuckle arms 42 .

The tie rod 41 is swingably connected to the rack shaft 30 via a ball joint 43 provided at the end of the rack shaft 30 . Note that the connecting portion that connects the rack shaft 30 and the tie rod 41 is not limited to the ball joint 43, and another type of universal joint may be used.

The output shaft 22 and the rack shaft 30 are connected to each other via a rack and pinion mechanism as a transmission mechanism including a pinion gear 22a provided at the end of the output shaft 22 and a rack gear 30a provided on the rack shaft 30. .

The pinion gear 22a and the rack gear 30a are meshed with each other, and the torque of the output shaft 22 is converted into a load in the axial direction of the rack shaft 30 via the pinion gear 22a and the rack gear 30a and transmitted to the rack shaft 30. As a result, the rack shaft 30 is displaced in the axial direction by the transmitted torque, and the wheels 1 are steered via the tie rods 41 .

The steering device 100 also includes an electric motor 50 as an electric unit that is driven to assist steering force in response to a steering operation, and a transmission mechanism that decelerates the rotation of the electric motor 50 and transmits it to the steering shaft 20. and a deceleration unit 52 .

The speed reducer 52 is a worm gear mechanism including a worm shaft 53 driven by the electric motor 50 and a worm wheel 54 provided on the output shaft 22 . The worm shaft 53 and the worm wheel 54 mesh with each other, and the torque of the electric motor 50 is transmitted to the output shaft 22 via the worm shaft 53 and the worm wheel 54 . The torque transmitted from the electric motor 50 to the output shaft 22 is further transmitted to the rack shaft 30 via the pinion gear 22a and the rack gear 30a.

The steering device 100 further includes a steering torque sensor 61 that detects torque acting on the torsion bar 23 and a controller 60 that controls driving of the electric motor 50 according to the detected value of the steering torque sensor 61 .

The controller 60 includes a CPU (Central Processing Unit) that performs arithmetic processing, a ROM (Read-Only Memory) that stores control programs and the like executed by the CPU, and a RAM (random access memory) that stores the calculation results of the CPU and the like. and a microcomputer including The controller 60 may be composed of a single microcomputer, or may be composed of a plurality of microcomputers.

The steering torque sensor 61 detects the steering torque applied to the input shaft 21 in accordance with the driver's steering operation, and outputs a voltage signal corresponding to the detected steering torque to the controller 60 . The controller 60 calculates the torque output by the electric motor 50 based on the voltage signal from the steering torque sensor 61, and controls the driving of the electric motor 50 so that the torque is generated.

Thus, in the steering device 100 having the above configuration, the steering torque sensor 61 detects the steering torque applied to the input shaft 21, and the controller 60 controls the driving of the electric motor 50 based on the detection result. It is possible to assist the driver's steering operation.

Here, in the steering device 100 configured as described above, driving torque is applied from the electric motor 50 to the rack shaft 30 via a transmission mechanism in which backlash exists, such as the speed reduction unit 52 and the rack and pinion mechanism. In addition, there is considerable play in the link mechanism such as the tie rod 41 and the knuckle arm 42 that connect the rack shaft 30 and the wheel 1 . That is, in the steering device 100 having the above configuration, there is play such as backlash that is intentionally provided on the path through which the driving torque of the electric motor 50 is transmitted to the wheels 1 .

Therefore, when the operating direction of the steering wheel 10 is the direction opposite to the previous operating direction, the electric motor 50 is not operated until the slack existing on the path for transmitting the drive torque of the electric motor 50 to the wheels 1 is reduced. The driving torque of 50 is not transmitted to the wheel 1. Therefore, there is a delay between when the electric motor 50 starts assisting in response to the driver's operation of the steering wheel 10 and when the wheels 1 actually start turning.

On the other hand, when the operation direction of the steering wheel 10 is the same as the previous operation direction, the play on the route for transmitting the driving torque of the electric motor 50 to the wheels 1 is reduced, that is, there is no play. It has become. Therefore, when the electric motor 50 starts assisting in response to the operation of the steering wheel 10 by the driver, the wheels 1 begin to steer with good responsiveness.

Therefore, for example, when the steering wheel 10 is steered in either the right or left direction from a straight running state in which the driver does not operate the steering wheel 10, the steering wheel 10 can be steered depending on whether or not there is play on the torque transmission path in the steering direction. The time from when the wheel 1 is turned to when the wheel 1 starts to steer changes. For this reason, the operability of the vehicle is degraded, and as a result, there is a risk that the driver's operational feeling will deteriorate.

Also, when a relatively large driving torque is generated in the electric motor 50, the backlash is rapidly reduced. There is a possibility that the gear rattling noise is generated in the transmission mechanism and gives discomfort to the driver.

In this embodiment, in order to avoid the occurrence of the phenomenon described above, the direction in which the driver operates the steering wheel 10 is predicted, and the play is controlled before the driving torque as the assist force is applied from the electric motor 50. By causing the electric motor 50 to generate pressing torque for tightening, the play on the path for transmitting the driving torque of the electric motor 50 to the wheel 1 is reduced in advance.

Next, with reference to FIGS. 1 and 2, a description will be given of a configuration that is provided in the steering device 100 having the above-described configuration to perform idle suppression control for preliminarily reducing the idle on the torque transmission path. FIG. 2 is a block diagram of the control system of the steering device 100. As shown in FIG.

As shown in FIG. 1, the steering device 100 includes a steering angle sensor 62 provided on the input shaft 21 for detecting the steering angle, which is the rotation angle of the steering wheel 10, a vehicle speed sensor 63 for detecting the speed of the own vehicle, a rack A steering state sensor 64 as a steering state detector that detects the steering state of the wheels 1 based on the amount of movement of the shaft 30 in the axial direction, and wirelessly obtains information on the own vehicle and the preceding vehicle traveling in front of the own vehicle. and an information acquisition unit 65 for acquiring information. The detected values detected by these sensors and the information obtained by the information obtaining section 65 are input to the controller 60 described above.

The steering angle sensor 62 has a center gear (not shown) that rotates together with the input shaft 21 and two outer gears (not shown) that mesh with the center gear. The rotation angle, that is, the rotation angle of the input shaft 21 is detected.

The steering state sensor 64 is a displacement sensor that detects the amount of movement of the rack shaft 30 in the axial direction. For example, a capacitance type or eddy current type displacement sensor is used. The steering state sensor 64 may be any sensor that can directly or indirectly detect the steering state of the wheels 1. It may be one that detects displacement. That is, the steering state sensor 64 can detect the displacement state of the portion that is displaced as the wheels 1 are steered without being affected by the backlash of the transmission mechanism.

The information acquisition unit 65 has a GPS (Global Positioning System) receiver and an external communication device. The information acquisition unit 65 receives radio waves transmitted from a plurality of GPS satellites by a GPS receiver, acquires the position information of the vehicle, and uses an external communication device to detect a plurality of units, such as 3 to 5 units, traveling in front of the vehicle. Acquire the position information and steering information of the preceding vehicle.

The steering information acquired by the external communication device of the information acquisition section 65 includes at least the steering direction and the position information of the vehicle when the steering is performed. Note that the preceding vehicle traveling in front of the own vehicle includes a vehicle that can be visually recognized in front of the driver and means a vehicle that has passed through the lane in which the own vehicle is traveling before the own vehicle. In other words, the external communication device acquires information as to where the vehicle that passed through the lane in which the vehicle is traveling ahead of the vehicle traveled while being steered in which direction, left or right.

The external communication device is, for example, a vehicle-to-vehicle communication device capable of transmitting and receiving vehicle information to and from an external communication device mounted on a preceding vehicle. In addition, the external communication device is not limited to the inter-vehicle communication device, and if it is possible to acquire the position information and steering information of the preceding vehicle traveling in front of the own vehicle, it communicates with the cloud network via the access point. It may be a device. In this way, by acquiring information from the cloud server, even if there is no preceding vehicle with which the vehicle-to-vehicle communication device can communicate, the vehicle passes through the lane in which the vehicle is traveling ahead of the vehicle. It is possible to acquire the information of the nearest multiple vehicles.

Next, with reference to FIG. 2, the functions of the controller 60 to which information is input from the sensors described above will be described.

The controller 60 includes a control execution determination unit 60a for determining whether or not to perform idle suppression control, and a control execution determining unit 60a for determining whether or not to perform idle suppression control, as functions for executing idle suppression control in the steering device 100 configured as described above. A vehicle-to-vehicle distance calculation unit 60b that calculates the vehicle-to-vehicle distance to the preceding vehicle, and a vehicle-to-vehicle distance that calculates a reference vehicle-to-vehicle distance between the vehicle and a preceding vehicle traveling in front of the vehicle according to the vehicle speed of the vehicle. A calculation unit 60c, a preceding vehicle information storage unit 60d that stores position information and steering information of multiple preceding vehicles acquired by an information acquisition unit 65, and multiple preceding vehicles stored in the preceding vehicle information storage unit 60d. A steering prediction unit 60e for predicting the steering state of the own vehicle based on the steering information of the steering prediction unit 60e, and based on the result predicted by the steering prediction unit 60e and the position information of the own vehicle acquired by the information acquisition unit 65. It has a pressing control section 60f that causes the electric motor 50 to generate pressing torque, and a current supply section 60g that supplies a current to the electric motor 50 according to a command from the pressing control section 60f. It should be noted that the control execution determination unit 60a and the like represent the respective functions of the controller 60 as virtual units, and do not mean that they physically exist.

The control execution determination unit 60a determines whether or not the play suppression control should be executed based on whether the steering wheel 10 is being operated by the driver. When the steering wheel 10 is being operated by the driver, that is, when the wheels 1 are turning left or right, there is no play in the torque transmission path. In such a case, it is determined that idle suppression control does not need to be executed because it is not necessary to perform idle reduction control.

On the other hand, when the steering wheel 10 is not operated by the driver, if the steering wheel 10 is operated in the direction opposite to the direction of the previous operation, there is a possibility that there is a gap in the torque transmission path. have a nature. In such a case, it is determined that idle suppression control needs to be performed because it is necessary to perform idle reduction control.

Specifically, when the detected value of the steering torque sensor 61 is equal to or less than a predetermined value and the detected value of the steering angle sensor 62 is equal to or less than a predetermined value, the control execution determination unit 60a determines that the steering wheel 10 is moved by the driver. Since it is not operated, it is determined that idle suppression control needs to be performed. Since there is a high possibility that the wheel 10 is being operated by the driver, it is determined that play suppression control does not need to be performed.

The predetermined value used for the above determination is set in consideration of the dead zone of each sensor and the fluctuation range of the detection value of each sensor that occurs only when the driver touches the steering wheel 10 . Note that only one of the steering torque sensor 61 and the steering angle sensor 62 may be used for the above determination.

Further, the control execution determination unit 60a determines whether idle suppression control should be executed based on the inter-vehicle distance between the own vehicle and the preceding vehicle traveling in front of the own vehicle. When the inter-vehicle distance between the own vehicle and the preceding vehicle traveling in front of the own vehicle is relatively short, it is conceivable that the vehicle is in a traffic jam. If the idle suppression control is performed when the distance between the vehicle and the preceding vehicle is relatively short, such as in a traffic jam, current is frequently supplied to the electric motor 50, resulting in an increase in power consumption. There is a risk of

In order to prevent the current from being wasted in this way, the control execution determination unit 60a performs idle suppression control when the inter-vehicle distance between the own vehicle and the preceding vehicle is longer than a predetermined reference inter-vehicle distance. is to be executed.

Specifically, the control execution determination unit 60a executes the idle suppression control when the inter-vehicle distance D calculated by the inter-vehicle distance calculation unit 60b is greater than or equal to the reference inter-vehicle distance D1 calculated by the reference inter-vehicle distance calculation unit 60c. If the inter-vehicle distance D is less than the reference inter-vehicle distance D1, it is determined that the idle suppression control should not be executed.

The vehicle-to-vehicle distance calculation unit 60b calculates the vehicle-to-vehicle distance D based on the position information of the own vehicle acquired by the information acquisition unit 65 and the position information of the preceding vehicle. A reference inter-vehicle distance D1 is calculated based on the vehicle speed of the own vehicle detected in . The reference inter-vehicle distance D1 is a so-called safe inter-vehicle distance. If the speed exceeds 80 km/h, it is the value of the speed per hour (eg, 80 m). Maps and formulas used to calculate the reference inter-vehicle distance D1 are stored in advance in the ROM of the controller 60 or the like.

When the vehicle speed detected by the vehicle speed sensor 63 is low, e.g. Based only on the vehicle speed of the vehicle, it may be determined that the idle suppression control should not be executed. A value detected by an inter-vehicle distance detector that detects the inter-vehicle distance using a laser or the like may be used as the inter-vehicle distance D used for determination in the control execution determination unit 60a.

When the steering predicting unit 60e receives a command from the control execution determining unit 60a that has determined to execute the idle suppression control, the steering predicting unit 60e will predict the vehicle in the future based on the steering information of the plurality of preceding vehicles stored in the preceding vehicle information storing unit 60d. Predict which direction the car will be steered, left or right, at which position.

Next, prediction of the steering direction and steering position of the own vehicle by the steering prediction unit 60e will be described with reference to FIGS. 3 to 5. FIG. 3 to 5 show the case where three vehicles A to C are traveling ahead of the own vehicle in the lane in which the own vehicle is traveling, with the lapse of time.

As shown in FIG. 3, when the steering direction of the preceding vehicle A traveling in front of the own vehicle changes, the information acquisition unit 65 obtains the steering direction of the preceding vehicle A and the position information of the preceding vehicle A when the steering was performed. and stored in the preceding vehicle information storage unit 60d. In the example shown in FIG. 3, the information that the preceding vehicle A is steered to the left at the steering point G is stored in the preceding vehicle information storage unit 60d.

Subsequently, as shown in FIG. 4, when the steering direction of the preceding vehicle B traveling in front of the own vehicle changes, the steering direction of the preceding vehicle B and the position information of the preceding vehicle B when the steering was performed are information. It is acquired via the acquisition unit 65 and stored in the preceding vehicle information storage unit 60d. In the example shown in FIG. 4, information that, like the preceding vehicle A, the preceding vehicle B is steered to the left at the steering point G is stored in the preceding vehicle information storage unit 60d.

Furthermore, as shown in FIG. 5, when the steering direction of the preceding vehicle C running immediately in front of the own vehicle changes, the steering direction of the preceding vehicle C and the position information of the preceding vehicle C when the steering was performed are information. It is acquired via the acquisition unit 65 and stored in the preceding vehicle information storage unit 60d. In the example shown in FIG. 5, information indicating that the preceding vehicle C is steered to the left at the steering point G is stored in the preceding vehicle information storage unit 60d, like the preceding vehicle A and the preceding vehicle B.

The steering predicting unit 60e refers to the steering information of the three preceding vehicles A to C stored in the preceding vehicle information storing unit 60d. Since the vehicle has been steered, it is predicted that the own vehicle will also be steered to the left at the same steering point G. In this case, the steering predicting unit 60e sets the left direction as the predicted steering direction of the own vehicle, and sets the steering point G at which the preceding vehicle C traveling immediately in front of the own vehicle was steered to the predicted steering point G1. Output to the pressing control unit 60f. Note that the predicted steering point G1 is not a strictly specified position, but is set as an approximate area on the driving lane, as shown in FIG. 5, taking into account GPS signal errors and data processing errors. be done.

On the other hand, if all three preceding vehicles A to C are not steered in the same direction, for example, if only one vehicle is steered, there is a possibility that an intersection or branch road exists at the steered position. Therefore, the steering prediction of the host vehicle is suspended.

In this way, the steering prediction unit 60e predicts the steering direction of the own vehicle and the steering prediction point where the own vehicle will be steered based on the steering information of the plurality of preceding vehicles A to C stored in the preceding vehicle information storage unit 60d. Predict G1. The number of preceding vehicles used for prediction in the steering prediction unit 60e is not limited to three, and may be one, two, or four or more. In order to improve the accuracy of predicting the steering direction and steering position of the own vehicle, it is preferable to use information from a plurality of vehicles (three or more). Further, the predicted steering point G1 is not the steering point G at which the preceding vehicle C running immediately in front of the host vehicle was steered, but a point including all the steering points G of the preceding vehicles A to C used for prediction. or the average of these points.

The preceding vehicle information storage unit 60d stores the steering information of a preset number of preceding vehicles at any time, while the steering information of the preceding vehicle at the point where the own vehicle has passed is deleted at any time. By updating the information stored in this way to new information, it becomes possible to accurately predict the steering direction and steering position of the own vehicle, and the data storage area can be reduced.

The pressing control unit 60f causes the electric motor 50 to generate a pressing torque for closing the slack when the position of the own vehicle approaches the steering prediction point G1 predicted by the steering prediction unit 60e. Here, even if the electric motor 50 is caused to generate a pressing torque to reduce the play when there is a considerable distance to the predicted steering point G1, when the predicted steering point G1 is reached, the play will again occur due to vibrations or the like during traveling. may have occurred. Therefore, the pressing control section 60f causes the electric motor 50 to generate pressing torque when the position of the own vehicle approaches the steering prediction point G1 to some extent.

Specifically, when the distance L from the vehicle position acquired by the GPS receiver of the information acquisition unit 65 to the steering prediction point G1 predicted by the steering prediction unit 60e becomes equal to or less than a predetermined distance L1, current is supplied. A command is sent to the section 60g to supply the electric motor 50 with current.

In addition, the idle suppression control must be executed before the vehicle is steered, that is, before the vehicle reaches the steering prediction point G1. set. Since the time required for the vehicle to reach the predicted steering point G1 varies depending on the vehicle speed of the vehicle, it is preferable to consider the vehicle speed of the vehicle when setting the predetermined distance L1.

The direction of the current supplied to the electric motor 50, that is, the direction of rotation of the electric motor 50 is included in the command from the pressing control unit 60f to the current supply unit 60g. The direction of rotation of the electric motor 50 commanded from the pressing control section 60f to the current supply section 60g is the predicted steering direction predicted by the steering prediction section 60e, and the pressing torque generated by the electric motor 50 is predicted by the steering prediction section 60e. Acts on predicted predictive steering direction.

The current supply unit 60g supplies a predetermined weak current in order to generate pressing torque in the electric motor 50 according to a command from the pressing control unit 60f.

Here, the magnitude of the pressing torque is sufficient as long as it can mainly reduce the backlash between the pinion gear 22a and the rack gear 30a and the backlash between the worm shaft 53 and the worm wheel 54, and the rack shaft 30 is displaced. In other words, it is set to a size that prevents the wheels 1 from being steered.

Therefore, the magnitude of the current supplied from the current supply section 60g to the electric motor 50 may be controlled based on the detected value of the steering state sensor 64 that detects the amount of axial movement of the rack shaft 30. For example, the current supplied to the electric motor 50 may be gradually increased, and the current supply may be stopped when the detected value of the steering state sensor 64 changes.

Next, with reference to the flow chart of FIG. 6 in addition to FIGS. The control shown in FIG. 6 is repeatedly executed by the controller 60 at predetermined time intervals.

First, in step S11, the control execution determination unit 60a determines whether or not the vehicle is being steered. If it is determined in step S11 that the vehicle is being steered, it is not necessary to reduce the slack, so the process is temporarily terminated.

On the other hand, if it is determined in step S11 that the vehicle is not being steered, the process proceeds to step S12. is calculated.

Subsequently, in step S13, the reference inter-vehicle distance calculation unit 60c calculates the reference inter-vehicle distance D1.

Next, in step S14, the calculated inter-vehicle distance D and the reference inter-vehicle distance D1 are compared in the control execution determining section 60a.

If the inter-vehicle distance D is less than the reference inter-vehicle distance D1, there is a possibility that the vehicle is in a traffic jam, so the process is temporarily terminated.

If the vehicle-to-vehicle distance D is equal to or greater than the reference vehicle-to-vehicle distance D1, it is determined that there is a need to perform idle suppression control, and the process proceeds to step S15.

In step S15, the steering information of the preceding vehicle is sequentially acquired by the preceding vehicle information storage unit 60d.

In the subsequent step S16, the steering prediction unit 60e determines whether or not the acquired steering information of the preceding vehicle matches a predetermined number of vehicles. For example, if the number of vehicles to be determined is set to three in advance, it is determined whether or not the steering positions and steering directions of the three preceding vehicles are the same.

In step S16, if the steering information of the preceding vehicle does not match or if the acquired steering information does not reach the predetermined number, the process proceeds to step S17 to update the steering information of the preceding vehicle.

On the other hand, if the steering information of the preceding vehicle matches in step S16, the process proceeds to step S18, and the predicted steering prediction point G1 of the own vehicle is set.

In the subsequent step S19, the pressing control unit 60f determines whether or not the distance L from the position of the host vehicle to the predicted steering point G1 has become equal to or less than the predetermined distance L1.

When the vehicle gradually approaches the predicted steering point G1 and the distance L from the position of the vehicle to the predicted steering point G1 becomes equal to or less than the predetermined distance L1, the process proceeds to step S20.

In step S20, current is supplied from the current supply section 60g to the electric motor 50 according to the command from the pressing control section 60f.

The electric motor 50 to which the electric current is supplied generates pressing torque that acts in the predicted steering direction predicted by the steering prediction unit 60e. Reduce the backlash between

In this manner, by causing the electric motor 50 to generate a pressing torque for closing the slack before the vehicle reaches the predicted steering point G1, the driving torque of the electric motor 50 can be increased before the vehicle is steered. It becomes possible to reduce the play on the route to be transmitted to the wheel 1 in advance. Therefore, the wheels 1 are stably steered with good responsiveness in accordance with the steering, regardless of the type of steering, and as a result, the operability of the vehicle can be improved. The operational feeling of the driver can be improved.

According to the above embodiment, the following effects are obtained.

In the steering device 100, the electric motor 50 is caused to generate pressing torque that closes the leeway on the torque transmission path in accordance with the steering direction and steering position of the own vehicle predicted based on the steering information of the preceding vehicles A to C. there is In this manner, the slack in the torque transmission path is reduced before steering is performed, so that the wheels 1 are steered stably with good responsiveness in response to the steering. It is possible to improve the operability of the vehicle provided with and improve the driver's operation feeling.

In addition, in the steering device 100, before the electric motor 50 generates a relatively large driving torque for steering the wheels 1, the slack in the torque transmission path is reduced. Therefore, the relatively large drive torque prevents the pinion gear 22a from hitting the rack gear 30a and the worm shaft 53 from hitting the worm wheel 54, thereby suppressing gear rattling noise in the transmission mechanism. . As a result, it is possible to prevent the driver from feeling uncomfortable.

Next, a modification of the above embodiment will be described. Modifications as shown below are also within the scope of the present invention, and it is possible to combine the configuration shown in the modification with the configuration described in the above embodiment, or to combine the configurations described in different modifications below. is also possible.

In the above embodiment, whether or not the position of the vehicle has approached the predicted steering point G1 predicted by the steering prediction section 60e is determined based on the distance L of the vehicle to the predicted steering point G1. Instead of this, the determination as to whether the position of the vehicle has approached the predicted steering point G1 to some extent may be made based on the predicted arrival time T until the vehicle reaches the predicted steering point G1.

Specifically, in the steering prediction unit 60e, in addition to the steering prediction point G1, the arrival prediction time T until the own vehicle reaches the steering prediction point G1 is predicted as needed based on the vehicle speed of the own vehicle. At 60f, when the predicted arrival time T becomes less than or equal to the predetermined time T1, it is determined that the position of the own vehicle has approached the steering prediction point G1 to some extent, and the electric motor 50 is caused to generate pressing torque. In the pressing control unit 60f, when the predicted arrival time T becomes equal to or less than the predetermined time T1, or when the distance L to the steering prediction point G1 becomes equal to or less than the predetermined distance L1, or both of these It may be determined that the position of the own vehicle has approached the predicted steering point G1 to some extent when the condition is satisfied.

Further, in the above embodiment, the output of the electric motor 50 is applied to the output shaft 22 connected to the input shaft 21 that rotates with the steering operation. The shaft to which the output of the electric motor 50 is applied is not limited to this, and may be the rack shaft 30, for example.

Moreover, when the output shaft is not connected to the input shaft that rotates with the steering operation, as in the steer-by-wire system, the output of the electric motor 50 may be applied to the output shaft.

Further, in the above-described embodiment, the steering device 100 is steered by the driver. Since the slack in the torque transmission path is reduced before the automatic steering is performed, the wheels 1 are steered stably with good response in response to the automatic steering, and as a result, It is possible to improve the operability of the automatic driving vehicle provided with the steering device 100 .

Further, in the above embodiment, the two wheels 1 are steered by the electric motor 50 via the rack shaft 30 . Alternatively, an independent steering system may be used in which each wheel 1 is steered by an electric motor 50 provided for each wheel 1 via a transmission mechanism or a link mechanism. In this case also, before the steering is performed, the slack in the transmission mechanism and the link mechanism interposed between the wheels 1 and the electric motor 50 is reduced, so that the wheels 1 are steered stably with good responsiveness in response to the steering. As a result, the operability of the vehicle equipped with the steering device 100 can be improved, and the driver's operation feeling can be improved.

In the above embodiment, a rack and pinion mechanism having a pinion gear 22a and a rack gear 30a is used as a transmission mechanism for transmitting the rotation of the output shaft 22 to the wheels 1. A link mechanism having a pitman arm that is angled may also be used. In this case also, the link mechanism is closed before the steering is performed, so that the wheels 1 are steered stably with good responsiveness in response to the steering. The operability of the vehicle can be improved, and the operational feeling of the driver can be improved.

Further, in the above-described embodiment, the electric motor 50 is caused to generate a pressing torque that closes the slack regardless of whether there is a slack in the predicted torque transmission path in the steering direction of the own vehicle. Alternatively, the electric motor 50 may be caused to generate a pressing torque that closes the slack only when it is determined that there is slack on the torque transmission path in the predicted steering direction of the vehicle. Regarding the presence or absence of clearance in the torque transmission path, for example, if the predicted steering direction of the vehicle is different from the direction in which the vehicle was steered immediately before, there is clearance, and the predicted steering direction of the vehicle is different. , and the direction in which the vehicle was steered immediately before are the same, it may be determined that there is no play.

Configurations, functions, and effects of embodiments of the present invention will be collectively described below.

The steering device 100 includes an electric motor 50 that generates drive torque for steering the wheels 1, a controller 60 that controls the driving of the electric motor 50, and information on the own vehicle and preceding vehicles A to C traveling in front of the own vehicle. The controller 60 includes a steering prediction unit 60e for predicting the steering state of the own vehicle based on the information on the preceding vehicles A to C obtained by the information acquisition unit 65, and a steering prediction unit 60e. and a pressing control unit 60f that causes the electric motor 50 to generate pressing torque that closes the play on the path for transmitting the driving torque to the wheels 1 based on the prediction result of .

In this configuration, the electric motor 50 is caused to generate pressing torque that closes the leeway on the torque transmission path according to the steering direction and steering position of the own vehicle predicted based on the steering information of the preceding vehicles A to C. . In this manner, the slack in the torque transmission path is reduced before steering is performed, so that the wheels 1 are steered stably with good responsiveness in response to the steering. It is possible to improve the operability of the vehicle provided with and improve the driver's operation feeling.

Further, in this configuration, before the electric motor 50 generates a relatively large drive torque for steering the wheels 1, the slack in the torque transmission path is reduced. Therefore, the relatively large drive torque prevents the pinion gear 22a from hitting the rack gear 30a and the worm shaft 53 from hitting the worm wheel 54, thereby suppressing gear rattling noise in the transmission mechanism. . As a result, it is possible to prevent the driver from feeling uncomfortable.

Also, the magnitude of the pressing torque is set to a magnitude that does not allow the wheels 1 to be steered.

In this configuration, the magnitude of the pressing torque is set to a magnitude that does not allow the wheels 1 to be steered. Therefore, the slack on the torque transmission path can be reliably reduced before steering is performed without affecting the operation of the vehicle. As a result, the wheels 1 are stably steered with good responsiveness in response to the steering operation, and the operability of the vehicle equipped with the steering device 100 can be improved, and the driver's operation feeling can be improved. can be done.

Further, the steering prediction unit 60e predicts the predicted steering direction of the own vehicle based on the information about the steering directions of the preceding vehicles A to C acquired by the information acquisition unit 65, and the pressing control unit 60f controls the electric motor 50 to The electric motor 50 is controlled so that the generated pressing torque acts in the predicted steering direction predicted by the steering prediction section 60e.

In this configuration, the pressing torque generated by the electric motor 50 acts in the predicted steering direction predicted by the steering prediction section 60e. By applying the pressing torque so as to reduce the slack on the torque transmission path in the predicted steering direction of the own vehicle in this way, the slack on the torque transmission path is reliably reduced before steering is performed. can be kept As a result, the wheels 1 are stably steered with good responsiveness in response to the steering operation, and the operability of the vehicle equipped with the steering device 100 can be improved, and the driver's operation feeling can be improved. can be done.

Further, based on the information about the steering points G of the preceding vehicles A to C acquired by the information acquisition unit 65, the steering prediction unit 60e determines the steering prediction point G1 where the own vehicle is steered and the steering prediction point G1. The pressing control unit 60f predicts at least one of the estimated arrival time T until the arrival of the steering point G1. When it is pressed, the electric motor 50 is caused to generate pressing torque.

In this configuration, when the distance L of the vehicle to the predicted steering point G1 is equal to or less than the predetermined distance L1 or the predicted arrival time T until the vehicle reaches the predicted steering point G1 is equal to or less than the predetermined time T1, the electric motor 50 is caused to generate pressing torque. By generating pressing torque in the electric motor 50 when the own vehicle approaches the predicted steering point G1 in this way, the slack on the torque transmission path can be reliably reduced immediately before the steering is performed. As a result, the wheels 1 are stably steered with good responsiveness in response to the steering operation, and the operability of the vehicle equipped with the steering device 100 can be improved, and the driver's operation feeling can be improved. can be done.

The controller 60 also includes an inter-vehicle distance calculation unit 60b that calculates an inter-vehicle distance D between the own vehicle and the preceding vehicle C based on the information of the own vehicle and the preceding vehicle C acquired by the information acquisition unit 65, and a reference inter-vehicle distance calculation unit 60c for calculating the reference inter-vehicle distance D1 based on the reference inter-vehicle distance D1.

In this configuration, the steering state of the own vehicle is predicted by the steering prediction unit 60e when the inter-vehicle distance D is greater than or equal to the reference inter-vehicle distance D1. When the inter-vehicle distance D is relatively short and there is a risk of traffic congestion, the steering state of the host vehicle is not predicted, and frequent current supply to the electric motor 50 is suppressed. power consumption can be reduced.

Further, the information acquisition unit 65 acquires information on the preceding vehicles A to C, and the steering prediction unit 60e acquires information on the preceding vehicles A to C based on the steering information on the preceding vehicles A to C acquired by the information acquisition unit 65. Predict the steering state of the own vehicle.

Further, when the steering directions of the preceding vehicles A to C are the same at a specific steering point G, the steering prediction unit 60e predicts that the own vehicle will also be steered in the same direction at the specific steering point G.

In these configurations, the steering state of the host vehicle is predicted based on the steering information of the preceding vehicles A to C. By predicting the steering state of the own vehicle based on the steering information of a plurality of preceding vehicles A to C in this manner, the steering state of the own vehicle can be predicted more efficiently than in the case of prediction based on the steering information of a single preceding vehicle. It can be predicted with high accuracy.

The steering device 100 further includes a steering state sensor 64 that detects the steering state of the wheels 1, and the pressing torque is set to a magnitude that does not change the detection value of the steering state sensor 64.

In this configuration, the magnitude of the pressing torque is set to a magnitude that does not change the detection value of the steering state sensor 64 . That is, the pressing torque is set to a magnitude that does not allow the wheels 1 to be steered. Therefore, the slack on the torque transmission path can be reliably reduced before steering is performed without affecting the operation of the vehicle. As a result, the wheels 1 are stably steered with good responsiveness in response to the steering operation, and the operability of the vehicle equipped with the steering device 100 can be improved, and the driver's operation feeling can be improved. can be done.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

DESCRIPTION OF SYMBOLS 100... Electric power steering apparatus (steering apparatus), 1... Wheel, 22a... Pinion gear (transmission mechanism), 30... Rack shaft (steering part), 30a... Rack gear (transmission mechanism) , 50... Electric motor (electric part), 52... Reduction part (transmission mechanism), 60... Controller (control part), 60a... Control execution determination part, 60b... Inter-vehicle distance calculation part , 60c...reference inter-vehicle distance calculation unit, 60d...preceding vehicle information storage unit, 60e...steering prediction unit, 60f...pressing control unit, 60g...current supply unit, 61...steering Torque sensor 62 Steering angle sensor 63 Vehicle speed sensor 64 Steering state sensor 65 Information acquisition unit

Claims (8)

an electric part that generates drive torque for steering the wheels;
a control unit that controls driving of the electric unit;
an information acquisition unit that acquires information on the own vehicle and a preceding vehicle traveling in front of the own vehicle,
The control unit
a steering prediction unit that predicts a steering state of the host vehicle based on the information of the preceding vehicle acquired by the information acquisition unit;
a pressing control unit that causes the electric unit to generate a pressing torque that closes the play on a path for transmitting the driving torque to the wheels based on the prediction result of the steering prediction unit;
When the steering wheel is being operated by the driver, it is determined that the pressing control unit does not need to perform control, and when the steering wheel is not being operated by the driver, it is determined that the pressing control unit needs to perform control. and a control execution determination unit for determining . 2. The electric power steering apparatus according to claim 1, wherein the magnitude of said pressing torque is set to a magnitude that does not allow said wheels to be steered. Further comprising a steering state detector that detects a steering state of the wheel,
3. The electric power steering apparatus according to claim 2, wherein the magnitude of said pressing torque is set to a magnitude that does not change the detection value of said steering state detector. The steering prediction unit predicts a predicted steering direction of the own vehicle based on the information about the steering direction of the preceding vehicle acquired by the information acquisition unit,
4. The pressing control section controls the electric section so that the pressing torque generated by the electric section acts in the predicted steering direction predicted by the steering prediction section. 1. The electric power steering device according to claim 1. Based on the information about the steering point of the preceding vehicle acquired by the information acquisition unit, the steering prediction unit is configured to steer the own vehicle until the vehicle reaches the predicted steering point. predict at least one of the predicted arrival times of
The pressing control unit causes the electric unit to generate the pressing torque when the distance of the vehicle to the predicted steering point is equal to or less than a predetermined distance or the predicted arrival time is equal to or less than a predetermined time. The electric power steering device according to any one of claims 1 to 4. The control unit
an inter-vehicle distance calculation unit that calculates an inter-vehicle distance between the own vehicle and the preceding vehicle based on the information of the own vehicle and the preceding vehicle acquired by the information acquisition unit;
a reference inter-vehicle distance calculation unit that calculates a reference inter-vehicle distance based on the vehicle speed of the own vehicle;
The electric power steering apparatus according to any one of claims 1 to 5, wherein the steering prediction unit predicts the steering state of the own vehicle when the inter-vehicle distance is equal to or greater than the reference inter-vehicle distance. . The information acquisition unit acquires information on the plurality of preceding vehicles,
7. The steering predicting unit predicts the steering state of the own vehicle based on the steering information of the plurality of preceding vehicles acquired by the information acquiring unit. The electric power steering device described in . 4. The steering predicting unit predicts that, when the steering directions of the preceding vehicles are the same at a specific point, the own vehicle will also be steered in the same direction at the specific point. 8. The electric power steering device according to 7.

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