JP5998960B2 - Driving assistance device - Google Patents

Description

The present invention relates to a driving support device .

  As a conventional driving support device and a control device mounted on a vehicle, for example, Patent Literature 1 discloses a steering wheel state detection device. This steering wheel steering state detection device detects a steering wheel steering state (when steering, releasing, holding, etc.) by the driver according to the work amount obtained by integrating the product of the time differential value of the steering angle and the steering torque.

JP 2004-175122 A

  By the way, the steering wheel state detection device described in Patent Document 1 described above, for example, when performing driving support according to the detection result, there is room for further improvement so that the driving support more reflects the driver's intention. There is.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a driving support device capable of realizing driving support reflecting the driver's intention.

  In order to achieve the above object, a driving support device according to the present invention includes a support device that performs driving support for a steering operation on a steering member of a vehicle, a steering angle detection device that detects a steering angle of the steering member, A torque detection device that detects a torque acting on a steering shaft that rotates together with the steering member, and the assist device are controlled, and return control that assists the switchback steering operation toward the neutral position of the steering member can be executed. A reference value in which a steering power according to a product of a parameter related to the steering angle detected by the steering angle detection device and a parameter related to the torque detected by the torque detection device is set in advance. The control amount of the return control is changed between the case described above and the case where the steering power is smaller than the reference value.

  In the driving support device, the control device may control the control amount of the return control relative to the steering power when the steering power is equal to or higher than the reference value, compared to the case where the steering power is smaller than the reference value. Can be made smaller.

  Further, in the driving support device, the control device is configured when the steering power is equal to or higher than the reference value and the torque detected by the torque detection device is equal to or higher than a predetermined torque set in advance. It is possible to make the control amount of the return control relatively small as compared with the case where the steering power is smaller than the reference value.

  In the driving support device, the control device may change a control amount of the return control according to the steering power when the steering power is smaller than the reference value.

  Further, in the driving support device, the control device continues the return control when the steering power is smaller than the reference value, while the steering power is increased when the steering power is equal to or higher than the reference value. The return control can be suppressed as compared with a case where the rate is smaller than the reference value.

  In the driving support device, the steering power is a product of a steering speed corresponding to the steering angle detected by the steering angle detection device and the torque detected by the torque detection device, or the steering angle detection device It can be calculated based on one or both of the products of the detected steering angle and the torque differential value corresponding to the torque detected by the torque detector.

  In order to achieve the above object, a control device according to the present invention controls a support device that performs driving support for a steering operation on a steering member of a vehicle, and assists a switchback steering operation toward a neutral position side of the steering member. And a steering power according to a product of a parameter related to a steering angle of the steering member and a parameter related to a torque acting on a steering shaft rotating together with the steering member. The control amount of the return control is changed between a case where the reference value is equal to or greater than a set reference value and a case where the steering power is smaller than the reference value.

The driving support device according to the present invention has an effect that driving support reflecting the driver's intention can be realized.

FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of the driving support apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the ECU according to the first embodiment. FIG. 3 is a diagram illustrating the meaning represented by the steering power in the driving support device according to the first embodiment. FIG. 4 is a diagram illustrating the meaning represented by the steering power in the driving support device according to the first embodiment. FIG. 5 is a schematic diagram illustrating an example of a traveling state of a vehicle equipped with the driving support apparatus according to the first embodiment. FIG. 6 is a diagram illustrating a compensation range for target return control. FIG. 7 is a block diagram illustrating an example of a schematic configuration of a target return control unit of the ECU according to the first embodiment. FIG. 8 is an example of a torque gain map of the ECU according to the first embodiment. FIG. 9 is a flowchart illustrating an example of control by the ECU according to the first embodiment. FIG. 10 is an example of an active torque gain map of the ECU according to the first embodiment. FIG. 11 is an example of a passive torque gain map of the ECU according to the first embodiment. FIG. 12 is a block diagram illustrating an example of a schematic configuration of a target return control unit of the ECU according to the second embodiment. FIG. 13 is a flowchart illustrating an example of control by the ECU according to the second embodiment.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of the driving support apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a schematic configuration of the ECU according to the first embodiment. 3 and 4 are diagrams for explaining the meanings represented by the steering power in the driving support apparatus according to the first embodiment. FIG. 5 is a schematic diagram illustrating an example of a traveling state of a vehicle equipped with the driving support apparatus according to the first embodiment. FIG. 6 is a diagram illustrating a compensation range for target return control. FIG. 7 is a block diagram illustrating an example of a schematic configuration of a target return control unit of the ECU according to the first embodiment. FIG. 8 is an example of a torque gain map of the ECU according to the first embodiment. FIG. 9 is a flowchart illustrating an example of control by the ECU according to the first embodiment. FIG. 10 is an example of an active torque gain map of the ECU according to the first embodiment. FIG. 11 is an example of a passive torque gain map of the ECU according to the first embodiment.

  A driving support apparatus 1 according to the present embodiment shown in FIG. 1 is mounted on a vehicle 2 and can perform driving support on the vehicle 2 and detects a driver's operation intention based on information on a steering system of the vehicle 2. It also has a function as an operation detection device. The driving support device 1 typically performs an active operation on the steering member and a passive operation on the steering member as operations reflecting the driver's operation intention based on a predetermined index corresponding to the information of the steering system. Make a distinction. And the driving assistance apparatus 1 implement | achieves the driving assistance which reflected the driver | operator's intention by reflecting the said determination result in the various control in the vehicle 2. FIG.

  Here, the active operation on the steering member is typically an operation in which the driver's intention to operate is relatively strongly reflected. On the other hand, the passive operation on the steering member is typically an operation in which the driver's steering intention is reflected relatively weakly, for example, a passive operation corresponding to disturbance or stability compensation. More specifically, the active operation on the steering member may include, for example, an aggressive steering operation in which the driver tries to move the vehicle 2 to the target position. The active operation is typically a state of actively working, a state of so-called myoelectricity, a state of actively issuing a command from the brain, etc. The operation is such that the vehicle 2 is shifted from the straight traveling state to the turning state by applying a force. On the other hand, the passive operation with respect to the steering member is, for example, a steering operation in which the driver tries to maintain the vehicle 2 at the target position against disturbance, a release operation in which the driver releases the hand, or a constant traveling direction of the vehicle 2 A steering operation for holding the steering member to maintain the steering member may be included. The passive operation is, for example, an operation in which a hand is put on the steering member to deal with road surface disturbance or the like.

  The driving support device 1 of the present embodiment reflects the determination result of the active operation and the passive operation based on the steering power in the driving support control of the steering system of the vehicle 2. Thereby, the driving assistance device 1 performs driving assistance of a steering system that does not depend on characteristics of the driver, for example.

  Specifically, as shown in FIG. 1, the driving support device 1 is mounted on a vehicle 2 and can support driving with the vehicle 2, and a steering angle sensor 10 as a steering angle detection device. And a torque sensor 11 as a torque detection device and an ECU 20 as a control device for controlling the support device 3. The steering angle sensor 10 detects the steering angle of a steering wheel (hereinafter abbreviated as “steering” unless otherwise specified) 4 as a steering member of the vehicle 2. The torque sensor 11 detects torque acting on a steering shaft (hereinafter, abbreviated as “shaft” unless otherwise specified) 5 as a steering shaft portion that rotates together with the steering 4. The support device 3 of this embodiment performs driving support for the steering operation to the steering 4 and includes a steering device 30 that constitutes a steering system of the vehicle 2.

  Here, the steering device 30 is mounted on the vehicle 2 and is a device for steering the steered wheels 40 of the vehicle 2. The steering device 30 of the present embodiment is a so-called electric power steering device (EPS) that assists the steering force of the vehicle 2 with the power of an electric motor or the like. The steering device 30 assists the driver's steering operation (steering operation) by driving an electric motor or the like so as to obtain a steering assist force corresponding to the steering force applied to the steering 4 from the driver.

  Specifically, as shown in FIG. 1, the steering device 30 includes a steering 4 as a steering member, a shaft 5 as a steering shaft, an R & P gear mechanism (hereinafter referred to as “gear mechanism” unless otherwise specified). 6), a pair of left and right tie rods 7, and an EPS device 8 as a steering actuator.

  The steering 4 is a member that can be rotated in the direction around the rotation axis X <b> 1 and is provided in the driver's seat of the vehicle 2. The driver can perform a steering operation (steering operation) by rotating the steering 4 about the rotation axis X1. That is, in the vehicle 2 on which the steering device 30 is mounted, the steering wheel 40 is steered by turning the steering 4 by the driver.

  The shaft 5 forms a rotating shaft portion of the steering 4. The shaft 5 has one end connected to the steering 4 and the other end connected to the gear mechanism 6. That is, the steering 4 is connected to the gear mechanism 6 via the shaft 5. The shaft 5 can rotate around the central axis along with the steering 4 as the driver rotates the steering 4. The shaft 5 may be divided into a plurality of members such as an upper shaft, an intermediate shaft, and a lower shaft, for example.

  The gear mechanism 6 mechanically connects the shaft 5 and the pair of tie rods 7. The gear mechanism 6 has, for example, a so-called rack and pinion type gear mechanism, and the rotational movement around the central axis of the shaft 5 corresponds to the left-right direction of the pair of tie rods 7 (typically corresponding to the vehicle width direction of the vehicle 2). ) Convert to linear motion.

  Each of the pair of tie rods 7 has a base end connected to the gear mechanism 6 and a tie rod end forming a front end connected to each steered wheel 40 via a knuckle arm. That is, the steering 4 is connected to each steered wheel 40 via the shaft 5, the gear mechanism 6, each tie rod 7, and the like.

  The EPS device 8 constitutes the support device 3 and is a steering actuator that operates in response to a steering operation to the steering 4. The EPS device 8 assists the steering operation (steering operation) on the steering 4 by the driver, and generates torque for assisting the steering operation. The EPS device 8 outputs a steering assist force (assist torque) that assists the steering force (torque) input to the steering 4 by the driver. In other words, the EPS device 8 supports the driver's steering operation by driving the steering wheel 40 of the vehicle 2 with an electric motor or the like. The EPS device 8 assists the driver's steering operation by applying an assist torque to the shaft 5. Here, the assist torque is torque that assists torque corresponding to the steering force input to the steering 4 by the driver.

  The EPS device 8 here has a motor 8a as an electric motor and a speed reducer 8b. The EPS device 8 of this embodiment is a column EPS device in which a motor 8a is provided on a shaft 5 such as an intermediate shaft, for example, a so-called column assist type assist mechanism.

  The motor 8a is a column assist electric motor that generates rotational power (motor torque) when electric power is supplied. For example, the motor 8a generates assist torque as a steering assist force. The motor 8a is connected to the shaft 5 through the speed reducer 8b or the like so as to be able to transmit power, and applies a steering assist force to the shaft 5 through the speed reducer 8b or the like. The speed reducer 8 b decelerates the rotational power of the motor 8 a and transmits it to the shaft 5.

  In the EPS device 8, when the motor 8a is rotationally driven, the rotational power (torque) generated by the motor 8a is transmitted to the shaft 5 via the speed reducer 8b, thereby performing steering assist. At this time, the rotational power generated by the motor 8a is decelerated by the speed reducer 8b, the torque is increased, and the torque is transmitted to the shaft 5. The EPS device 8 is electrically connected to an ECU 20 described later, and the drive of the motor 8a is controlled.

  The steering angle sensor 10 detects the steering angle of the steering 4 as described above, and is a rotation angle sensor in the steering system. Here, the steering angle sensor 10 detects the steering angle as an absolute angle. The steering angle sensor 10 detects a steering angle (steering wheel steering angle) that is a rotation angle of the steering 4. The steering angle detected by the steering angle sensor 10 is detected, for example, as a positive value on the counterclockwise side and a negative value on the clockwise side with reference to the neutral position of the steering wheel 4, but the reverse may be possible. The neutral position of the steering wheel 4 is a position serving as a reference for the steering angle, and is typically the position of the steering wheel 4 when the vehicle 2 travels straight ahead. The steering angle detected by the steering angle sensor 10 is 0 ° at the neutral position of the steering 4. The steering angle sensor 10 is electrically connected to the ECU 20 and outputs a detection signal corresponding to the detected steering angle to the ECU 20.

  Note that the steering angle detection device of the driving support device 1 is not limited to the steering angle sensor 10, and for example, the rotation angle sensor 12 that detects the rotation angle of the rotor shaft of the motor 8 a, the rack stroke or pinion rotation angle of the gear mechanism 6. A sensor (not shown) for detecting, a sensor (not shown) for detecting the turning angle of the steered wheels 40, or the like can also be used. In this case, if the steering angle detection device is a sensor that detects the steering angle as a relative angle, such as the rotation angle sensor 12, for example, if the steering angle detection device has a function capable of acquiring the absolute angle of the steering 4 separately. Good.

  The torque sensor 11 detects torque acting on the shaft 5 as described above. Here, the torque sensor 11 detects torque acting on the shaft 5, in other words, torque generated on the shaft 5. The torque sensor 11 detects, for example, torque acting on a torsion bar (not shown) that is a torsion member that constitutes a part of the EPS device 8. The torque detected by the torque sensor 11 (hereinafter sometimes referred to as “steering torque”) is typically driver steering that acts on the shaft 5 in accordance with the steering force input to the steering 4 from the driver. The torque reflects the disturbance torque input to the shaft 5 from the steering wheel 40 via the tie rod end in accordance with the torque, road surface disturbance input to the steering wheel 40, and the like. For example, the torque detected by the torque sensor 11 is detected as a positive value on the counterclockwise side and a negative value on the clockwise side, but this may be reversed. The torque sensor 11 is electrically connected to the ECU 20 and outputs a detection signal corresponding to the detected steering torque to the ECU 20.

  The ECU 20 controls each part of the vehicle 2 on which the driving support device 1 is mounted. The ECU 20 is an electronic circuit mainly composed of a known microcomputer including a CPU, a ROM, a RAM, and an interface. The ECU 20 is electrically connected to various sensors such as the torque sensor 11, the steering angle sensor 10, the rotation angle sensor 12, and the EPS device 8 described above. The rotation angle detected by the rotation angle sensor 12 is used, for example, for current control (output control) to the motor 8a by the ECU 20. Here, the ECU 20 is further electrically connected to the vehicle speed sensor 13 and the like. The vehicle speed sensor 13 detects a vehicle speed that is the traveling speed of the vehicle 2. In addition to this, the ECU 20 may be electrically connected to various sensors such as a current sensor that detects various currents, a lateral G sensor that detects lateral acceleration acting on the vehicle 2, and a detector.

  The ECU 20 receives electrical signals (detection signals) corresponding to the detection results from various sensors, and outputs a drive signal to the EPS device 8 according to the input detection results to control the drive. The ECU 20 can execute control for adjusting the torque generated by the EPS device 8 based on the detected steering operation physical quantity.

  For example, the ECU 20 controls the EPS device 8 based on the steering torque detected by the torque sensor 11 and adjusts and controls the assist torque generated by the EPS device 8 and acting on the shaft 5. The ECU 20 adjusts the output torque of the motor 8a by adjusting the motor supply current, which is the supply current to the motor 8a, and adjusts the assist torque. Here, the motor supply current is a current having a magnitude that allows the EPS device 8 to generate a predetermined torque required. At this time, the ECU 20 may control the motor supply current to the motor 8a based on the rotation angle detected by the rotation angle sensor 12, for example.

  In the steering device 30 configured as described above, the torque generated by the EPS device 8 under the control of the ECU 20 and the like are applied to the shaft 5 together with the steering torque input to the steering 4 from the driver. When the steering force and the steering assist force are applied to the tie rod 7 from the shaft 5 through the gear mechanism 6, the steering device 30 responds to the driver steering torque generated by the driver and the torque generated by the EPS device 8. The steering wheel 40 is steered by being displaced in the left-right direction by the axial force of the magnitude. As a result, the steering device 30 can steer the steered wheels 40 by the steering force input to the steering 4 from the driver and the steering assist force generated by the EPS device 8, thereby the steering by the driver. The operation can be assisted, and the burden on the driver can be reduced during the steering operation.

  The ECU 20 of the present embodiment executes, for example, assist control, damping control, target return control, and the like as control related to steering system driving support using the steering device 30 constituting the support device 3. The ECU 20 can control the EPS device 8 of the steering device 30 based on the detection results of the various sensors described above, and can execute assist control, damping control, and target return control. These controls are performed by adjusting the torque generated by the EPS device 8.

  As described above, the assist control is a control for generating an assist force that assists the steering operation on the steering 4 by the driver by the EPS device 8. Damping control is control in which the EPS device 8 generates a damping force that simulates damping corresponding to the viscosity characteristic of the steering device 30. The steering device 30 tends to suppress the steering speed of the steering wheel 4 by applying a damping force that acts in a direction to suppress the steering speed of the steering wheel 4 by the damping control. Can be granted. The target return control is a return control that assists the steering operation for returning the steering wheel 4 toward the neutral position. More specifically, in the target return control, a steering wheel return force (handle return torque) is applied in the neutral position direction of the steering wheel 4 by the EPS device 8 in accordance with the target steering speed, so that the steering wheel 4 is smoothly in the neutral position. It is control to return to the side. The return control of the present embodiment is described as target return control corresponding to the target steering speed, but is not limited to this, and instead of the target steering speed, the return control is performed toward the neutral position side according to the steering angle. This may be so-called steering wheel return control that assists the switch back steering operation.

  FIG. 2 is a block diagram illustrating an example of a schematic configuration of the ECU according to the first embodiment. The ECU 20 includes, for example, an assist control unit 21, a damping control unit 22, a target return control unit 23, an adder 24, and the like in terms of functions.

  The assist control unit 21 calculates a basic assist control amount in the assist control. The assist control unit 21 receives a detection signal corresponding to the vehicle speed V from the vehicle speed sensor 13 and receives a detection signal corresponding to the steering torque T from the torque sensor 11. The assist control unit 21 calculates a target assist torque according to a basic assist force as a basic assist control amount by various methods based on the input detection signal. The assist control unit 21 outputs a current command value signal corresponding to the calculated basic assist control amount to the adder 24.

  The damping control unit 22 calculates a damping control amount in the damping control. The damping control unit 22 receives a detection signal corresponding to the vehicle speed V from the vehicle speed sensor 13, and receives a detection signal corresponding to the steering speed θ ′ based on the steering angle θ from the steering angle sensor 10. The damping control unit 22 calculates a torque corresponding to the target damping force as a damping control amount by various methods based on the input detection signal. The damping control unit 22 outputs a current command value signal corresponding to the calculated damping control amount to the adder 24.

  The target return control unit 23 calculates a target return control amount in the target return control. The target return control unit 23 receives a detection signal corresponding to the vehicle speed V from the vehicle speed sensor 13, receives a detection signal corresponding to the steering torque T from the torque sensor 11, and performs steering based on the steering angle θ from the steering angle sensor 10. A detection signal corresponding to the speed θ ′ is input, a detection signal corresponding to the motor angular speed ω based on the rotation angle of the rotor shaft of the motor 8a is input from the rotation angle sensor 12, and the steering angle sensor 10 corresponds to the steering angle θ. Detection signal is input. The target return control unit 23 calculates a handle return torque corresponding to a target steering speed as a target return control amount by various methods based on the input detection signal. The target return control unit 23 outputs a current command value signal corresponding to the calculated target return control amount to the adder 24.

  The adder 24 receives a current command value signal corresponding to the basic assist control amount from the assist control unit 21, and receives a current command value signal corresponding to the damping control amount from the damping control unit 22. A current command value signal corresponding to the target return control amount is input. The adder 24 is a target steering control amount (current command value corresponding to the final target torque) obtained by adding the basic assist control amount, the damping control amount, and the target return control amount based on the input current command value signal. ) Is calculated. The adder 24 outputs a current command value signal corresponding to the calculated target steering control amount to the EPS device 8 as an EPS assist command, and controls the motor 8a of the EPS device 8. Thereby, ECU20 implement | achieves the above assist control, damping control, and target return control.

  Then, the ECU 20 of the present embodiment uses the steering 4 as a predetermined index according to the information of the steering system based on the parameter related to the steering angle detected by the steering angle sensor 10 and the parameter related to the steering torque detected by the torque sensor 11. The active operation on the steering wheel 4 and the passive operation on the steering wheel 4 are distinguished and determined. Here, the ECU 20 determines the active operation and the passive operation based on the steering power according to the product of the parameter related to the steering angle detected by the steering angle sensor 10 and the parameter related to the steering torque detected by the torque sensor 11. . The ECU 20 can detect the strength of the active operation and the passive operation and then apply the control to the control.

  The ECU 20 of the present embodiment controls the steering device 30 that constitutes the support device 3 based on the determination result, and changes the control amount of the driving support by the support device 3, here the target return control using the steering device 30. To do. That is, the ECU 20 controls the steering device 30 based on the steering power corresponding to the product of the parameter related to the steering angle detected by the steering angle sensor 10 and the parameter related to the steering torque detected by the torque sensor 11, and performs target return control. Change the control amount. For example, the ECU 20 changes the control amount of the target return control when the steering power is equal to or higher than a preset reference value and when the steering power is smaller than the reference value.

  Here, the steering power used for the control by the ECU 20 will be described. The steering power typically has a tendency to represent a transient steering operation by the driver's intention.

The steering power is an index that represents the power in the steering operation of the driver with respect to the steering 4, and is a physical quantity that represents energy used per unit time. The steering power P can be expressed by the following mathematical formula (1) using the steering work W when the time is “t”. Here, the steering work amount W is an index representing work in the steering operation of the driver with respect to the steering 4 and is a physical quantity representing used energy.

P = dW / dt (1)

Here, the steering power P is, for example, the product of the steering speed (corresponding to the differential value of the steering angle) θ ′ corresponding to the steering angle θ detected by the steering angle sensor 10 and the steering torque T detected by the torque sensor 11. Alternatively, it is calculated based on one or both of the product of the steering angle θ detected by the steering angle sensor 10 and the torque differential value T ′ corresponding to the steering torque T detected by the torque sensor 11. The steering power P based on the product [θ ′ · T] of the steering speed θ ′ and the steering torque T typically has a tendency to reflect a course change intention or the like in a transient steering operation by a driver's intention. It is in. On the other hand, the steering power P based on the product [θ · T ′] of the steering angle θ and the torque differential value T ′ typically corresponds to the reverse input from the road surface in the transient steering operation by the driver's intention. It tends to reflect the intentions of others. For example, the ECU 20 detects an active operation on the steering 4 when the steering power P is equal to or higher than a preset power reference (reference value) ThP, and the steering power P is smaller than the power reference value ThP. In this case, a passive operation on the steering 4 is detected.
The setting of the work rate reference value ThP will be described in detail later.

The ECU 20 is based on one or both of the product [θ ′ · T] of the steering speed θ ′ and the steering torque T or the product [θ · T ′] of the steering angle θ and the torque differential value T ′. The steering power P is calculated, the driver's intention is determined based on this, and reflected in the control using the support device 3 (steering device 30). The ECU 20 may determine the driver's intention using one of the steering power P based on the product [θ ′ · T] and the steering power P based on [θ · T ′]. However, the determination of the driver's intention may be performed using both of them. Further, the ECU 20 determines a driver's intention by calculating a steering power P obtained by combining the steering power based on the product [θ ′ · T] and the steering power based on the product [θ · T ′]. May be performed. The ECU 20 can calculate the steering power P using, for example, the following formula (2).

P = A · [θ ′ · T] + B · [θ · T ′] (2)

  In the above formula (2), “A” and “B” are coefficients, which are suitable values that can be set as appropriate based on various conditions, actual vehicle evaluation, and the like. The ECU 20 arbitrarily sets the coefficients A and B in the above formula (2), for example, according to the use of the calculated steering power P, the characteristics of the vehicle 2, the characteristics of the driver, and the like. Can be adjusted. For example, when it is desired to change the driving support by determining the active operation and the passive operation reflecting the driver's intention to change the course, the ECU 20 sets the steering power by setting A = 1 and B = 0. The calculation formula of P can be simplified. Similarly, when it is desired to change the driving support by determining the active operation and the passive operation while reflecting the intention of the driver to respond to the reverse input, the ECU 20 performs steering by setting A = 0 and B = 1. The calculation formula of the work rate P can be simplified. Further, the ECU 20 can calculate the steering power P by combining the product [θ ′ · T] and the product [θ · T ′] at a desired ratio by arbitrarily adjusting the coefficients A and B. . Thereby, since ECU20 can change distribution of the reflection degree of each intention in the steering work rate P, it becomes possible to determine active operation and passive operation appropriately according to a situation, and to change driving assistance.

The ECU 20 may further calculate the steering power P by applying Stevens' law to the above formula (2). In this case, for example, the ECU 20 may apply [k1 · θ ′ ^a1 · k2 · T ^a2 ] instead of [θ ′ · T] in the above formula (2). Similarly, the ECU 20 may apply [k3 · θ ^a3 · k4 · T ' ^a4 ] instead of [θ · T'] in the above formula (2), for example. “K1”, “k2”, “k3”, “k4”, “a1”, “a2”, “a3”, “a4” are coefficients and can be set as appropriate based on various conditions, actual vehicle evaluation, and the like. Conformity value. As a result, the ECU 20 can linearly convert a non-linear physical quantity with respect to the driver's feeling, for example, so that the steering power P can be set to a value more suited to the driver's feeling and more Judgment and driving support according to the sense of the person.

  Next, the meaning represented by the steering power P calculated as described above will be described with reference to FIGS. FIG. 3 is an example of a steering characteristic diagram for explaining the meaning represented by the steering power P based on the product [θ ′ · T], in which the horizontal axis represents the steering torque T and the vertical axis represents the steering speed θ ′. FIG. 4 is an example of a steering characteristic diagram illustrating the meaning represented by the steering power P based on the product [θ · T ′], where the horizontal axis indicates the (steering) torque differential value T ′ and the vertical axis indicates the steering angle θ. It is said.

  In FIG. 3, an equal driver intention line L11 indicated by a plurality of dotted lines is a set of operating points (a combination of the steering speed θ ′ and the steering torque T) representing the equal driver intention. Here, since the steering power P can be used as an indicator representing the driver's intention, the operating point representing the equal driver intention is, in other words, the steering power P (that is, the product [θ ′ · T]). This corresponds to a combination of the steering speed θ ′ and the steering torque T that are equivalent. That is, each equal driver intention line L11 is a set of combinations of the steering speed θ ′ and the steering torque T at which the steering power P is equal. When [θ ′ · T] = P (constant), since it can be transformed to θ ′ = P / T, each equal driver intention line L11 is a right-angled hyperbola. For example, the operating point A and the operating point B in FIG. 3 are both located on the same equal driver intention line L11. Therefore, the combination of the steering speed θ ′ and the steering torque T at the operating point A and the combination of the steering speed θ ′ and the steering torque T at the operating point B are determined by the driver performing the steering operation with the same steering intention. Can be seen as being.

  For example, when the driver performs an active operation on the steering 4, the operating point determined by the combination of the steering speed θ ′ and the steering torque T is located in the vicinity of the region T 11 in the steering characteristic diagram shown in FIG. Tend to. On the other hand, for example, when the driver performs a passive operation on the steering 4, the operating point determined by the combination of the steering speed θ ′ and the steering torque T is located in the vicinity of the regions T12, T13, and T14 in FIG. There is a tendency. More specifically, when the driver does not perform the steering operation itself as the passive operation, the operating point determined by the combination of the steering speed θ ′ and the steering torque T is located in the vicinity of the region T12 in FIG. There is a tendency. When the driver holds the steering as the passive operation, the operating point determined by the combination of the steering speed θ ′ and the steering torque T tends to be located in the vicinity of the region T13 in FIG. When passive operation is performed by the driver (or when there is no axial force such as jack-up), the operating point determined by the combination of the steering speed θ ′ and the steering torque T is in the vicinity of the region T14 in FIG. Tend to be located.

  The relationship between each operating point as shown in FIG. 3 and each region T11, T12, T13, T14 can be specified in advance according to the actual vehicle evaluation or the like. Therefore, the ECU 20 can determine the driver's intention according to the region where the operating point determined by the combination of the detected steering speed θ ′ and the steering torque T is located in the steering characteristic diagram shown in FIG. . That is, for example, when the operating point determined by the combination of the steering speed θ ′ and the steering torque T is in the region T11, the ECU 20 can estimate and determine that the driver has performed an active operation.

  The power reference value ThP used for discrimination between the active operation and the passive operation described above is based on the steering power P when the active operation is performed and the steering power P when the passive operation is performed. Are preset. Here, for example, the first power reference value ThP1 is set based on the steering characteristic diagram shown in FIG. The first power reference value ThP1 is a power reference value ThP set for the steering power P based on the product [θ ′ · T]. The first power reference value ThP1 can be set based on the equal driver intention line L11 located at the boundary between the active operation region and the passive operation region in the steering characteristic diagram shown in FIG. That is, for example, an equal driver intention line L11 (or an operating point determined by a combination of the steering speed θ ′ and the steering torque T) located at the boundary between the active operation area and the passive operation area based on the actual vehicle evaluation or the like is set. Identify. Then, the steering power P (product [θ ′ · T]) represented by the specified equal driver intention line L11 (or operating point) is set as the first power reference value ThP1.

  Similarly, an equal driver intention line L21 indicated by a plurality of dotted lines in FIG. 4 is a set of operating points (a combination of the steering angle θ and the torque differential value T ′) representing the equal driver intention. In other words, the operating point representing the equal driver intention corresponds to a combination of the steering angle θ and the torque differential value T ′ having the same steering power P (that is, the product [θ · T ′]). That is, each equal driver intention line L21 is a set of combinations of the steering angle θ and the torque differential value T ′ at which the steering power P becomes equal. When [θ · T ′] = P (constant), since it can be transformed to θ = P / T ′, each equal driver intention line L21 is a right-angled hyperbola.

  For example, when the driver performs an active operation on the steering wheel 4, the operating point determined by the combination of the steering angle θ and the torque differential value T ′ is in the vicinity of the region T21 in the steering characteristic diagram shown in FIG. Tend to be located. On the other hand, for example, when the driver performs a passive operation on the steering wheel 4, the operating point determined by the combination of the steering angle θ and the torque differential value T ′ is located in the vicinity of the regions T22, T23, and T24 in FIG. Tend to. More specifically, when the driver does not perform the steering operation itself as the passive operation, the operating point determined by the combination of the steering angle θ and the torque differential value T ′ is located in the vicinity of the region T22 in FIG. Tend to. As a passive operation, when a steering operation is performed against disturbance by the driver, the operating point determined by the combination of the steering angle θ and the torque differential value T ′ tends to be located in the vicinity of the region T23 in FIG. . As a passive operation, when the driver performs a steering operation during a turn, the operating point determined by the combination of the steering angle θ and the torque differential value T ′ tends to be located in the vicinity of the region T24 in FIG.

  The relationship between each operating point as shown in FIG. 4 and each region T21, T22, T23, T24 can be specified in advance according to actual vehicle evaluation or the like. Therefore, the ECU 20 can determine the driver's intention according to the region where the operating point determined by the combination of the detected steering angle θ and the torque differential value T ′ is located in the steering characteristic diagram shown in FIG. it can.

  Here, for example, the second power reference value ThP2 is set based on the steering characteristic diagram shown in FIG. The second power reference value ThP2 is a power reference value ThP that is set with respect to the steering power P based on the product [θ · T ′]. The second power reference value ThP2 can be set based on the equal driver intention line L21 located at the boundary between the active operation region and the passive operation region in the steering characteristic diagram shown in FIG. That is, for example, an equal driver intention line L21 located at the boundary between the active operation region and the passive operation region based on actual vehicle evaluation or the like (or an operating point determined by a combination of the steering angle θ and the torque differential value T ′). Is identified. Then, the steering power P (product [θ · T ′]) represented by the specified equal driver intention line L21 (or operating point) is set as a second power reference value ThP2.

  The power reference value ThP is calculated as a steering power P obtained by combining the product [θ ′ · T] and the product [θ · T ′] at a desired ratio using the above formula (2) or the like. When determining an active operation and a passive operation, they may be set in the same manner as described above.

  For example, the ECU 20 determines that the steering power P is the power reference value ThP based on the power reference value ThP set as described above and the steering power P calculated using Equation (2) or the like. The active operation is detected in the above case, and the passive operation is detected when the steering power P is smaller than the power reference value ThP. Then, the ECU 20 changes the control amount of the target return control using the steering device 30 between the active operation and the passive operation. That is, in other words, the ECU 20 performs target return control using the steering device 30 when the steering power P is equal to or higher than the power reference value ThP and when the steering power P is smaller than the power reference value ThP. Change the control amount. For example, the ECU 20 individually calculates the steering power P based on the product [θ ′ · T] and the steering power P based on the product [θ · T ′], and changes the control amount of the target return control. In this case, the above-described first power reference value ThP1 and second power reference value ThP2 may be used as the power reference value ThP.

  In addition, the magnitude of the steering power P represents the strength of the driver's intention (will of active operation, will of passive operation). Therefore, the ECU 20 may reflect the calculated magnitude of the steering power P in the control amount of the target return control. That is, the ECU 20 may change the control amount (assist torque, motor supply current, etc.) of the EPS device 8 (steering actuator) of the steering device 30 constituting the support device 3 based on the steering power P. . Thereby, the ECU 20 can reflect the strength of the driver's intention detected through the steering power P in the target return control, compensate the strength of the driver's intention, and drive according to the strength of the driver's intention. Can provide support.

  As described above, the ECU 20 according to the present embodiment changes the control amount of the target return control between the active operation and the passive operation based on the steering power P and the power reference value ThP.

  Here, for example, as illustrated in FIG. 5, a case where the vehicle 2 on which the driving support device 1 is mounted is traveling on a highway ramp way or the like will be described as an example. The compensation range of the target return control in this case will be described with reference to FIG. In the upper left table in FIG. 6, for example, the compensation range of the target return control by the ECU according to the comparative example that determines the presence or absence of the target return control according to the magnitude of the steering torque T is shown. In this case, the ECU according to the comparative example, when the vehicle 2 is traveling on a highway rampway or the like, if the absolute value of the steering angle θ is larger than a predetermined value and the absolute value of the steering torque T is smaller than a predetermined value (0 It is determined that the operation is a hand-off operation. In this case, the ECU according to the comparative example can obtain the control effect of assisting the switch-back steering operation by releasing the target by performing the target return control. On the other hand, if the absolute value of the steering angle θ is larger than a predetermined value and the steering torque T is larger than a predetermined value, the ECU according to the comparative example determines that the operation is a cutting operation. In this case, the ECU according to the comparative example does not perform the target return control during the cutting operation regardless of the active operation or the passive operation.

  However, even in such a cutting operation, there is a scene where it is desired to improve the steering wheel return characteristic by performing the target return control depending on the situation, but whether or not the target return control according to the magnitude of the steering torque T is determined. However, it tends to be difficult to classify detailed control. For example, when an active operation is performed, such as when the driver wants to further cut and bend due to the driver's active intention, the target return control can be suppressed to achieve clean steering characteristics. On the other hand, for example, when a passive operation is performed, such as passively applying a torque to a change in vehicle behavior due to a disturbance or the like, the target return control is continued to assist the switchback steering operation and to improve the steering wheel return characteristic. It is possible to improve.

  Therefore, as described above, the ECU 20 of the present embodiment discriminates the driver's active operation and passive operation based on the steering power P and the power reference value ThP, and in the case of active operation and passive operation. Then, the control amount of the target return control is changed. The ECU 20 performs target return control (driving support) corresponding to the active operation with respect to the steering 4 when the steering power P is equal to or higher than the power reference value ThP, and steering when the steering power P is smaller than the power reference value ThP. The target return control (driving support) corresponding to the passive operation with respect to 4 is assumed. As a result, the ECU 20 achieves driving assistance that reflects the driver's intention.

  Here, the ECU 20 uses the steering power P1 based on the product [θ ′ · T] and the product [θ · T ′] as an index for determining active operation and passive operation, that is, the steering power P. Is used, and the first work rate reference value ThP1 and the second work rate reference value ThP2 are used as the work rate reference value ThP. When the steering power P1 is equal to or higher than the first power reference value ThP1, or when the steering power P2 is equal to or higher than the second power reference value ThP2, the ECU 20 is assumed to have been actively operated by the driver. judge. The ECU 20 determines that the driver has performed a passive operation when the steering power P1 is smaller than the first power reference value ThP1 and the steering power P2 is smaller than the second power reference value ThP2.

  The ECU 20 continues the target return control when it is determined that a passive operation has been performed by the driver, as shown in the table regarding the compensation range of the target return control at the lower right in FIG. When it is determined that an active operation has been performed by a person, the target return control is suppressed as compared with a case where it is determined that a passive operation has been performed. That is, the ECU 20 performs the target return control when the steering power P (steering power P1, steering power P2) is smaller than the power reference value ThP (first power reference value ThP1, second power reference value ThP2). On the other hand, when the steering power P is equal to or higher than the power reference value ThP, the target return control is suppressed as compared with the case where the steering power P is smaller than the power reference value ThP.

  Specifically, the ECU 20 is a power factor reference in which a steering power P corresponding to a product of a parameter related to the steering angle θ detected by the steering angle sensor 10 and a parameter related to the steering torque T detected by the torque sensor 11 is set. When the value is equal to or greater than the value ThP, the target return control is suppressed by relatively reducing the target return control amount of the target return control as compared with the case where the steering power P is smaller than the power reference value ThP. That is, the ECU 20 is typically based on the steering power P (steering power P1, steering power P2) and the power reference value ThP (first power reference value ThP1, second power reference value ThP2). Thus, when it can be determined that the driver has performed an active operation, the target return control is suppressed by relatively reducing the target return control amount as compared with the case where it can be determined that the driver has performed a passive operation.

  Here, as an example, the ECU 20 has a steering power P (steering power P1, steering power P2) equal to or higher than a power reference value ThP (first power reference value ThP1, second power reference value ThP2). In this case, when the steering torque T detected by the torque sensor 11 is equal to or greater than a predetermined torque set in advance, the target return control amount is relatively compared with the case where the steering power P is smaller than the power reference value ThP. By making it smaller, target return control is suppressed.

  On the other hand, when the steering power P (the steering power P1, the steering power P2) is smaller than the power reference value ThP (the first power reference value ThP1, the second power reference value ThP2), the ECU 20 By changing the target return control amount according to the rate P, the target return control is continued. That is, in this case, the ECU 20 continues the target return control even when the steering torque T is equal to or greater than a predetermined torque set in advance, and adjusts the target return control amount according to the steering power P.

  For example, the ECU 20 of the present embodiment makes a target based on the steering power P by making the torque gain used when the target return control unit 23 calculates the target return control amount variable based on the steering power P. Change the return control amount.

  FIG. 7 is a block diagram illustrating an example of a schematic configuration of the target return control unit 23. The target return control unit 23 is, for example, functionally conceptually, a steering speed target value calculation unit 23a, a subtractor 23b, a P control amount calculation unit 23c, a vehicle speed gain calculation unit 23d, a differential calculation unit 23e, an index calculation unit 23f, active A passive determination unit 23g, an LPF (low-pass filter) 23h, a torque gain calculation unit 23i, a multiplier 23j, an LPF (low-pass filter) 23k, a guard processing unit 23l, and the like are configured.

  The steering speed target value calculation unit 23a calculates a target steering speed (target steering angular speed) in the target return control. A detection signal corresponding to the steering angle θ is input from the steering angle sensor 10 to the steering speed target value calculation unit 23a. The steering speed target value calculation unit 23a calculates a target steering speed based on the input detection signal, and outputs a calculation signal corresponding to the target steering speed to the subtractor 23b. The steering speed target value calculation unit 23a calculates a target steering speed from the steering angle θ based on, for example, a target steering speed map (or a mathematical model corresponding thereto). The steering speed target value calculation unit 23a typically sets the target steering speed to 0 when the steering angle θ is 0 (neutral position), and moves toward the neutral direction side as the absolute value of the steering angle θ increases. Increase the absolute value of the target steering speed.

  The subtracter 23b receives a calculation signal corresponding to the target steering speed from the steering speed target value calculation unit 23a, and a detection signal corresponding to the motor angular speed ω corresponding to the rotation angle of the rotor shaft of the motor 8a from the rotation angle sensor 12. Is entered. The subtractor 23b calculates a target steering speed difference value Δθ ′ obtained by subtracting the current motor angular speed ω from the target steering speed as a feedback control amount based on the input calculation signal and detection signal. The subtractor 23b outputs a calculation signal corresponding to the calculated target steering speed difference value Δθ ′ to the P control amount calculation unit 23c.

  The P control amount calculation unit 23c calculates a control amount of so-called PID control (Proportional Integral Derivative Controller). The P control amount calculator 23c receives a calculation signal corresponding to a target steering speed difference value Δθ ′ that is a difference between the target steering speed and the current motor angular speed ω from the subtractor 23b. The P control amount calculation unit 23c calculates a target handle return torque that is the basis of the target return control amount based on the input calculation signal. The P control amount calculator 23c outputs a current command value signal corresponding to the calculated target handle return torque to the multiplier 23j.

  The vehicle speed gain calculating unit 23d calculates a vehicle speed gain used when calculating the target return control amount. The vehicle speed gain calculation unit 23d receives a detection signal corresponding to the vehicle speed V from the vehicle speed sensor 13. The vehicle speed gain calculation unit 23d calculates a vehicle speed gain based on the input detection signal, and outputs a gain signal corresponding to the vehicle speed gain to the multiplier 23j. The vehicle speed gain calculation unit 23d calculates a vehicle speed gain from the vehicle speed V based on, for example, a vehicle speed gain map (or a mathematical model corresponding thereto). The vehicle speed gain calculation unit 23d typically decreases the vehicle speed gain as the vehicle speed V increases. Thus, the ECU 20 can relatively reduce the target return control amount as the vehicle speed V increases.

  The differential calculation unit 23e calculates a torque differential value T ′ of the steering torque T. The differential calculation unit 23 e receives a detection signal corresponding to the steering torque T from the torque sensor 11. The differential calculation unit 23e calculates a torque differential value T ′ of the steering torque T based on the input detection signal, and outputs a calculation signal corresponding to the torque differential value T ′ to the index calculation unit 23f.

  The index calculator 23f calculates an index for determining active operation and passive operation. The index calculation unit 23 f receives a detection signal corresponding to the steering speed θ ′ based on the steering angle θ from the steering angle sensor 10, and receives a detection signal corresponding to the steering torque T from the torque sensor 11. Is input with a detection signal corresponding to the steering angle θ, and a calculation signal corresponding to the torque differential value T ′ is input from the differential calculation unit 23e. The index calculation unit 23f of the present embodiment uses, as the index, a first power calculation unit 23m that calculates a steering power P1 based on the product [θ ′ · T], and a steering based on the product [θ · T ′]. A second power calculation unit 23n that calculates the power P2 is included. The index calculation unit 23f is not limited to this, and may be configured without any of the first work rate calculation unit 23m and the second work rate calculation unit 23n, or the product [θ ′ · T] and the product An arithmetic unit that calculates a steering power P obtained by combining [θ · T ′] may be included.

  The first power calculation unit 23m receives a detection signal corresponding to the steering speed θ ′ based on the steering angle θ from the steering angle sensor 10 and a detection signal corresponding to the steering torque T from the torque sensor 11. The first power calculation unit 23m calculates the product of the steering speed θ ′ (t) in the current control cycle and the steering torque T (t) in the current control cycle based on the input detection signal. Thus, the steering power P1 is calculated. The first power calculation unit 23m outputs a calculation signal corresponding to the calculated steering power P1 to the active / passive determination unit 23g.

  The second power calculation unit 23n receives a detection signal corresponding to the steering angle θ from the steering angle sensor 10, and receives a calculation signal corresponding to the torque differential value T ′ from the differential calculation unit 23e. Based on the input detection signal and calculation signal, the second power calculation unit 23n calculates the steering angle θ (t) in the current control cycle and the torque differential value T ′ (t) in the current control cycle. The steering power P2 is calculated by calculating the product. The second power calculation unit 23n outputs a calculation signal corresponding to the calculated steering power P2 to the active / passive determination unit 23g.

  The active / passive determination unit 23g determines the driver's active / passive operation. The active / passive determination unit 23g receives a calculation signal corresponding to the steering power P1 from the first power calculation unit 23m, and receives a calculation signal corresponding to the steering power P2 from the second power calculation unit 23n. . The active / passive determination unit 23g performs an active operation by the driver based on the input calculation signal and the first power reference value ThP1 and the second power reference value ThP2 set in advance as described above. Determine whether it has been done.

Here, the active / passive determination unit 23g performs an active operation by the driver when it is determined that a period satisfying one or more of the following conditions 1 and 2 has continued for a predetermined period set in advance. It is determined that On the other hand, when the active / passive determination unit 23g determines that a period that satisfies one or more of the following conditions 1 and 2 is not less than a predetermined period, neither of the following conditions 1 or 2 is satisfied. It is determined that the driver has performed a passive operation. The predetermined period may be set in advance as a period during which active operation and passive operation can be reliably determined, for example.

(Condition 1) The steering power P1 is greater than or equal to the first power reference value ThP1 (P1 ≧ ThP1).

(Condition 2) The steering power P2 is equal to or greater than the second power reference value ThP2 (P2 ≧ ThP2).

  Here, when the active / passive determination unit 23g determines that the period satisfying one or more of the above conditions 1 and 2 has continued for a predetermined period, the driver performs an active operation. Although described as what is determined to have been made, it is not limited to this. For example, the active / passive determination unit 23g may determine that an active operation has been performed by the driver when it is determined that the period satisfying all of the above conditions 1 and 2 has continued for a predetermined period. .

  Then, the active / passive determination unit 23g outputs, to the LPF 23h, a calculation signal corresponding to an index representing the strength of the passive operation together with the determination signal corresponding to the determination result. Here, as described above, the magnitude of the steering work rate P also represents the strength of the driver's intention (intention of active operation, intention of passive operation). Therefore, here, the active / passive determination unit 23g outputs a calculation signal corresponding to the steering power P to the LPF 23h as an index indicating the strength of the passive operation. The index indicating the strength of the passive operation is that as the steering power P is relatively large (the steering power P is smaller than the work power reference value ThP and the absolute value is relatively small), the intention of the passive operation is relatively This means that the steering power P is relatively small (the steering power P is smaller than the work power reference value ThP and the absolute value is relatively large), and the intention of the passive operation is relatively strong ( Large). The active / passive determination unit 23g uses the steering power P1 input from the first power calculation unit 23m and the steering power input from the second power calculation unit 23n as the steering power P indicating the strength of the passive operation. An arithmetic signal corresponding to the steering power P obtained by combining the product [θ ′ · T] and the product [θ · T ′] based on the rate P2 or the above-described equation (2) is output to the LPF 23h. In this case, the coefficients A and B may be set to arbitrary values.

  The LPF 23h receives from the active / passive determination unit 23g a determination signal corresponding to the determination result regarding the active operation and a calculation signal corresponding to an index (steering power P) indicating the strength of the passive operation. The LPF 23h applies a frequency component other than a predetermined low frequency component for the purpose of noise removal for the purpose of stabilization of control with respect to the calculation signal corresponding to the index (steering work rate P) indicating the strength of the passive operation input. Perform filtering to be removed. The LPF 23h outputs a determination signal corresponding to the determination result for the active operation and the calculation signal subjected to the filter process to the torque gain calculation unit 23i.

  The torque gain calculation unit 23i calculates a torque gain used when calculating the target return control amount. The torque gain calculation unit 23i receives a detection signal corresponding to the steering torque T from the torque sensor 11, receives a determination signal corresponding to the determination result regarding the active operation from the LPF 23h, and an index (steering work) indicating the strength of the passive operation. An arithmetic signal (filtered signal) corresponding to the rate P) is input. The torque gain calculation unit 23i calculates a torque gain based on the input detection signal, determination signal, and calculation signal, and outputs a gain signal corresponding to the torque gain to the multiplier 23j.

  When it is determined by the active / passive determination unit 23g that the driver has performed an active operation, the torque gain calculation unit 23i is passive by the driver if the steering torque T is equal to or greater than a predetermined torque. The torque gain is relatively reduced as compared with the case where it is determined that the operation has been performed. Thereby, the ECU 20 is in a case where the steering power P (steering power P1, steering power P2) is equal to or higher than the power reference value ThP (first power reference value ThP1, second power reference value ThP2). Thus, when the steering torque T is equal to or greater than the predetermined torque, the target return control amount can be made relatively small as compared with the case where the steering power P is smaller than the power reference value ThP.

  On the other hand, when the active / passive determining unit 23g determines that the driver has performed a passive operation, the torque gain calculating unit 23i performs torque according to an index (steering power P) indicating the strength of the passive operation. Change the gain. Thus, the ECU 20 performs steering when the steering power P (steering power P1, steering power P2) is smaller than the power reference value ThP (first power reference value ThP1, second power reference value ThP2). The target return control amount can be changed according to the work rate P.

  As an example, the torque gain calculation unit 23i calculates a torque gain from the steering torque T based on, for example, a torque gain map (or a mathematical model corresponding to this) m1 as illustrated in FIG. Here, in the torque gain map m1, the horizontal axis indicates the steering torque T, and the vertical axis indicates the torque gain. The torque gain map m1 describes the relationship between the steering torque T and the torque gain. The torque gain map m1 is stored in the storage unit of the ECU 20 after the relationship between the steering torque T and the torque gain is set in advance based on actual vehicle evaluation and the like.

  In the torque gain map m1 illustrated in FIG. 8, the line L31 represents the torque gain when it is determined that the driver has performed an active operation, and the line L32 has been determined to have been passively operated by the driver. Represents the torque gain in the case. A plurality of lines L32 are set according to an index (steering power P) indicating the strength of passive operation. When it is determined that the driver has actively operated the torque gain, that is, the steering power P (steering power P1, steering power P2) is the power reference value ThP (first power reference value ThP1). , When the steering torque T is less than the predetermined torque, the steering torque T is constant when the steering torque T is lower than the predetermined torque, and when the steering torque T is higher than the predetermined torque, as shown by the line L31. As T increases, it decreases and finally becomes zero. Here, the predetermined torque may be arbitrarily set in advance according to, for example, actual vehicle evaluation. Further, when it is determined that the driver has performed a passive operation, that is, when the steering power P is smaller than the power reference value ThP, the torque torque T is calculated as indicated by a line L32. The region below the predetermined torque is equivalent to the case where the driver performs an active operation, is greater than 0 when the steering torque T is greater than the predetermined torque, and is larger than the torque gain when the driver performs the active operation. Set to a value. When it is determined that the driver has performed the passive operation, the torque gain decreases as the index indicating the strength of the passive operation decreases (increases in the steering power P) and at least the steering torque T Becomes constant in the region of the upper limit torque (upper limit torque> predetermined torque) or more. Here, the upper limit torque may be arbitrarily set in advance according to, for example, actual vehicle evaluation. When it is determined that the driver has performed an active operation, the torque gain calculation unit 23i determines from the steering torque T a torque gain during active operation (hereinafter referred to as “active torque gain” based on the line L31 of the torque gain map m1. And a gain signal corresponding to the active torque gain is output to the multiplier 23j. When it is determined that the driver has performed a passive operation, the torque gain calculation unit 23i, based on the line L32 of the torque gain map m1, determines the torque gain (hereinafter referred to as “passive torque gain”) from the steering torque T. And a gain signal corresponding to the passive torque gain is output to the multiplier 23j.

  The multiplier 23j amplifies the current command value signal corresponding to the target handle return torque by the vehicle speed gain and the torque gain. The multiplier 23j receives a current command value signal corresponding to a basic target handle return torque from the P control amount calculator 23c, and receives a gain signal corresponding to the vehicle speed gain from the vehicle speed gain calculator 23d. A gain signal corresponding to the torque gain is input from the calculation unit 23i. The multiplier 23j multiplies the current command value signal corresponding to the target steering wheel return torque by the vehicle speed gain and the torque gain, amplifies the signal, calculates the target steering wheel return torque corrected by the vehicle speed gain and the torque gain, and performs the correction. The current command value signal corresponding to the target handle return torque is output to the LPF 23k.

  At this time, the multiplier 23j is calculated by the torque gain calculation unit 23i when it is determined that the driver has performed an active operation, that is, when the steering power P is equal to or higher than the power reference value ThP. The corrected target handle return torque is calculated using the above-described active torque gain. As a result, the ECU 20 compares the corrected target handle return torque relative to the case where it is determined that the driver has performed a passive operation (when the steering power P is smaller than the power reference value ThP). Thus, the final target return control amount can be made relatively small.

  On the other hand, when it is determined that the driver has performed a passive operation, that is, when the steering power P is smaller than the power reference value ThP, the multiplier 23j calculates the above-described value calculated by the torque gain calculator 23i. The corrected target handle return torque is calculated using the passive torque gain. As a result, the ECU 20 can adjust the corrected target handle return torque according to the steering power P, which is an index indicating the strength of passive operation, and eventually the final target according to the driver's intention. The return control amount can be adjusted.

  The LPF 23k receives a current command value signal corresponding to the corrected target handle return torque from the multiplier 23j. The LPF 23k performs a filtering process for removing a frequency component other than a predetermined low frequency component for the purpose of noise removal for the purpose of stabilizing the control on the current command value signal corresponding to the inputted target handle return torque. The LPF 23k outputs the current command value signal subjected to the filtering process to the guard processing unit 23l.

  The guard processing unit 23l receives a current command value signal corresponding to the target handle return torque after the filtering process from the LPF 23k. The guard processing unit 23l performs a guard process on the current command value signal corresponding to the target handle return torque after the filter process based on a predetermined upper and lower limit value in order to suppress a sudden change in the target return control amount, The final target return control amount is calculated, and a current command value signal corresponding to the target return control amount (final target handle return torque after guard processing) is output to the adder 24.

  As a result, the ECU 20 can realize target return control that reflects the driver's intention according to each case when an active operation is performed or a passive operation is performed. That is, the ECU 20 continues the target return control when it is determined that a passive operation has been performed by the driver, while it is determined that a passive operation has been performed when it is determined that an active operation has been performed by the driver. The target return control can be suppressed as compared with the case where the target return control is performed.

  Next, an example of control by the ECU 20 will be described with reference to FIG. Note that these control routines are repeatedly executed at a control cycle of several ms to several tens of ms.

  First, the ECU 20 measures the steering torque T, the steering speed θ ′, and the steering angle θ based on the detection results of the steering angle sensor 10 and the torque sensor 11 (step ST1).

  Next, the ECU 20 calculates a torque differential value T ′ = dT / dt based on the steering torque T measured in step ST1 (step ST2).

  Next, based on the steering torque T, the steering speed θ ′, the steering angle θ, and the torque differential value T ′ calculated in step ST2, the ECU 20 performs the steering power P1 in the current control cycle. = Θ ′ (t) · T (t) and steering power P2 = θ (t) · T ′ (t) are calculated (step ST3).

  Next, the ECU 20 determines whether or not an active operation is performed by the driver based on the steering power P1 and the steering power P2 calculated in step ST3 (step ST4). The ECU 20 determines whether or not an active operation has been performed by the driver, for example, by determining whether or not the state of (P1 ≧ ThP1) or (P2 ≧ ThP2) has continued for a predetermined period or longer.

  When it is determined in step ST4 that the driver has performed an active operation (step ST4: Yes), the ECU 20 selects an active torque gain as a torque gain used when calculating the target return control amount (step ST5), which will be described later. The process proceeds to step ST7. In this case, the ECU 20 calculates an active torque gain from the steering torque T based on, for example, an active torque gain map (or a mathematical model corresponding thereto) m1-1 illustrated in FIG. Note that the active torque gain map m1-1 illustrated in FIG. 10 corresponds to a map corresponding to the line L31 of the torque gain map m1 described in FIG.

  On the other hand, if the ECU 20 determines in step ST4 that no active operation has been performed by the driver, that is, a passive operation has been performed (step ST4: No), the ECU 20 is passive as a torque gain used in calculating the target return control amount. A torque gain is selected (step ST6), and the process proceeds to step ST7 described later. In this case, the ECU 20 calculates a passive torque gain from the steering torque T based on, for example, a passive torque gain map (or a mathematical model corresponding thereto) m1-2 as illustrated in FIG. Note that the passive torque gain map m1-2 illustrated in FIG. 11 corresponds to a map corresponding to the line L32 of the torque gain map m1 described in FIG. In the passive torque gain map m1-2 in FIG. 11, three lines L32a, L32b, and L32c are illustrated as the line L32, and an index representing the strength of the passive operation is based on the above-described formula (2). In this example, the steering power P, which is a combination of the product [θ ′ · T] and the product [θ · T ′], is used. In this case, the passive torque gain decreases as the steering power P increases.

  In the process of step ST7, the ECU 20 calculates a target return control amount using the torque gain selected in step ST5 or step ST6, and issues an EPS assist command based on the target return control amount to the EPS device 8. The target return control is executed by executing the compensation control for the target return control amount (step ST7), the current control cycle is terminated, and the next control cycle is started.

  In the driving support device 1 configured as described above, when the steering power corresponding to the product of the parameter related to the steering angle and the parameter related to the steering torque is equal to or higher than a preset reference value, When the value is smaller than the reference value, the control amount of the driving support by the support device 3, here, the target return control using the steering device 30 is changed. Thereby, the driving assistance apparatus 1 can implement | achieve the target return control which reflected the driver | operator's intention according to each, when an active operation is made, a passive operation is made, etc. In other words, the driving support device 1 determines the active operation and the passive operation by distinguishing them based on the steering power and the like, and reflects the determined operation intention of the driver in the target return control, so that the driver feels uncomfortable. Less driving assistance can be provided.

  More specifically, the driving support device 1 has a case where the steering power is equal to or higher than the power reference value (when it can be determined as an active operation), and a case where the steering power is smaller than the power reference value (when it can be determined as a passive operation). ), The steering wheel return torque by the target return control is made relatively small. Thus, the driving support device 1 continues the target return control as usual when the steering power is smaller than the power reference value, while the steering power is higher than the work power when the steering power is equal to or higher than the power reference value. The target return control can be suppressed as compared with the case where it is smaller than the rate reference value.

  Here, the driving assistance device 1 is the steering power when the steering power is equal to or higher than the power standard value (when it can be determined as active operation) and the steering torque is equal to or higher than a predetermined torque set in advance. Is smaller than the case where the power is smaller than the power reference value, and the target return control amount is relatively small, typically 0. As a result, when it can be determined that the driver has performed an active operation on the steering wheel 4, the driving support device 1 can suppress the driver's operation from being restricted by the target return control. It is possible to suppress the hindering of the comfortable steering operation.

  On the other hand, the driving assistance device 1 changes the target return control amount according to the steering power when the steering power is smaller than the power reference value (when it can be determined as passive operation). As a result, the driving support device 1 can improve the steering wheel return characteristic when the steering torque is large, for example, even when the driver performs a passive operation. As a result, when it can be determined that the driver has performed a passive operation on the steering 4, the driving support device 1 can appropriately apply the steering wheel return torque by the target return control, and the operation by the driver can be performed easily. Can be made.

  As a result, the driving support device 1 is actively operated when, for example, when the vehicle 2 is traveling on a highway ramp way or the like, and when it is desired to further cut and turn with the driver's active intention. In such a case, by suppressing the target return control, a clear steering characteristic can be obtained. On the other hand, the driving assistance device 1 continues the target return control when the passive operation is performed, for example, when passively applying torque to a change in vehicle behavior due to a disturbance or the like, thereby performing the return steering operation. Auxiliary steering wheel return characteristics can be improved.

  According to the driving support device 1 according to the embodiment described above, the support device 3 that performs driving support for the steering operation of the vehicle 2 to the steering 4, the steering angle sensor 10 that detects the steering angle of the steering 4, and the steering A torque sensor 11 that detects torque acting on the shaft 5 that rotates together with the ECU 4, and an ECU 20 that controls the support device 3 and can execute a return control that assists the steering operation to return to the neutral position of the steering 4. Prepare. The ECU 20 sets a reference value (a steering power P1, P2, etc.) corresponding to a product of a parameter related to the steering angle detected by the steering angle sensor 10 and a parameter related to the torque detected by the torque sensor 11 in advance. The control amount of the target return control (return control) is changed depending on whether it is greater than or equal to the first work rate reference value ThP1, the second work rate reference value ThP2, etc. .

  Therefore, the driving assistance device 1 and the ECU 20 are driving assistance that reflects the driver's intention based on the steering power when the driver performs an active operation or when a passive operation is performed. Thus, target return control can be realized, and for example, driving assistance with less discomfort for the driver can be performed.

  As described above, the return control according to the present embodiment is described as target return control. However, the present invention is not limited to this, and the handle return that assists the switchback steering operation toward the neutral position according to the steering angle is merely performed. Control etc. may be sufficient. Even in this case, the driving support device 1 and the ECU 20 can realize the steering wheel return control that reflects the driver's intention based on the steering power.

[Embodiment 2]
FIG. 12 is a block diagram illustrating an example of a schematic configuration of a target return control unit of the ECU according to the second embodiment. FIG. 13 is a flowchart illustrating an example of control by the ECU according to the second embodiment. The driving support device and the control device according to the second embodiment are different from the first embodiment in the content of the control. In addition, about the structure, operation | movement, and effect which are common in embodiment mentioned above, the overlapping description is abbreviate | omitted as much as possible. Moreover, FIG. 1 etc. are referred suitably about each structure of the driving assistance apparatus which concerns on Embodiment 2, and a control apparatus.

  The ECU 20 of the driving support device 201 of this embodiment illustrated in FIG. 12 is configured to include a target return control unit 223 in place of the target return control unit 23 (see FIG. 2) in terms of functional concept. The target return control unit 223 according to the present embodiment directly calculates the torque gain based on the steering power P without performing the active / passive operation determination based on the steering power P, and the target return control amount. Thus, a target return control amount reflecting the driver's intention is calculated.

  The target return control unit 223 is, for example, functionally conceptually, a steering speed target value calculation unit 23a, a subtractor 23b, a P control amount calculation unit 23c, a vehicle speed gain calculation unit 23d, a differential calculation unit 23e, an index calculation unit 223f, and an LPF. (Low-pass filter) 223g, passive operation gain calculation unit 223h, multiplier 23j, LPF (low-pass filter) 23k, guard processing unit 23l and the like. The steering speed target value calculation unit 23a, subtractor 23b, P control amount calculation unit 23c, vehicle speed gain calculation unit 23d, differentiation calculation unit 23e, multiplier 23j, LPF (low pass filter) 23k, and guard processing unit 23l are shown in FIG. Therefore, the description thereof is omitted as much as possible.

  In addition to the first power calculation unit 23m and the second power calculation unit 23n, the index calculation unit 223f of the present embodiment performs steering based on the product [θ ′ · T] as an index for setting the torque gain. A third power calculation unit 223o that calculates a steering power P obtained by combining the power P1 and the steering power P2 based on the product [θ · T ′] is included. The third power calculation unit 223o is based on the above-described formula (2), the steering power P1 calculated by the first power calculation unit 23m, the steering power P2 calculated by the second power calculation unit 23n, and Is calculated. In this case, the coefficients A and B may be set to arbitrary values. The third power calculation unit 223o outputs a calculation signal corresponding to the combined steering power P to the LPF 223g. As described above, the magnitude of the steering power P also represents the strength of the driver's intention (intention of active operation, intention of passive operation). The index calculator 223f may output a calculation signal corresponding to the steering power P1 or the steering power P2 to the LPF 223g instead of the combined steering power P.

  The LPF 223g receives a calculation signal corresponding to the steering power P from the third power calculation unit 223o of the index calculation unit 223f. The LPF 223g performs a filter process for removing a frequency component other than a predetermined low frequency component for the purpose of noise removal for the purpose of stabilizing the control on the calculation signal corresponding to the steering power P. The LPF 223g outputs the calculation signal subjected to the filter processing to the passive operation gain calculation unit 223h.

  The passive operation gain calculator 223h calculates a torque gain used when calculating the target return control amount. The passive operation gain calculation unit 223h receives a calculation signal (filtered signal) corresponding to the steering power P from the LPF 223g. The passive operation gain calculation unit 223h calculates a torque gain based on the input calculation signal, and outputs a gain signal corresponding to the torque gain to the multiplier 23j.

  As an example, the passive operation gain calculation unit 223h calculates a torque gain from the steering power P based on, for example, a torque gain map (or a mathematical model corresponding to this) m2 as illustrated in FIG. Here, in the torque gain map m2, the horizontal axis indicates the steering power P, and the vertical axis indicates the torque gain. The torque gain map m2 describes the relationship between the steering power P and the torque gain. The torque gain map m2 is stored in the storage unit of the ECU 20 after the relationship between the steering power P and the torque gain is set in advance based on actual vehicle evaluation and the like. In the torque gain map m2, the torque gain indicates that the strength of the active operation performed by the driver increases as the steering power P increases, and the power corresponding to the power reference value ThP (in the torque gain map m2) For example, it represents that the strength of the passive operation increases as the steering power P decreases with the boundary at the intersection of the vertical axis and the horizontal axis. In the torque gain map m2, the torque gain decreases with an increase in the steering power P, and finally becomes 0 in a region equal to or higher than the first predetermined power. Further, in the torque gain map m2, the torque gain increases as the steering power P decreases, and becomes constant in a region below the second predetermined power. Here, the first predetermined power and the second predetermined power may be arbitrarily set in advance according to, for example, actual vehicle evaluation. The first predetermined power and the second predetermined power are typically set according to the above-described predetermined torque and upper limit torque. The above power reference value ThP is located between the first predetermined power and the second predetermined power. The torque gain map m2 indicates that when the steering power P is equal to or higher than the power reference value ThP (when it can be determined that the driver has performed an active operation), or when the steering power P is smaller than the power reference value ThP (the driver The torque gain is set so that the return control amount is relatively small as compared with the case where it is possible to determine that the passive operation has been performed. More specifically, the torque gain map m2 indicates that when the steering power P is smaller than the power reference value ThP, the target return control is continued as usual, and when the steering power P is equal to or higher than the power reference value ThP, The torque gain is set so that the target return control amount is relatively suppressed as compared with the case where the work rate P is smaller than the work rate reference value ThP. The passive operation gain calculator 223h calculates a torque gain from the steering power P based on the torque gain map m2, and outputs a gain signal corresponding to the torque gain to the multiplier 23j.

  Therefore, the ECU 20 can change the control amount of the target return control based on the steering power P by making the torque gain variable based on the steering power P by the passive operation gain calculating unit 223h. That is, the ECU 20 typically has the steering power P smaller than the power reference value ThP when the steering power P is equal to or higher than the power reference value ThP (when it can be determined that an active operation has been performed by the driver). Compared to the case (when it can be determined that the driver has performed a passive operation), the torque gain can be made relatively small, and the target return control amount can be made relatively small. That is, for example, the ECU 20 continues the target return control when the steering power P is smaller than the power reference value ThP, while the steering power P is equal to the steering power P when the steering power P is above the power reference value ThP. It is possible to suppress the target return control as compared with the case where it is smaller than the work rate reference value ThP.

  Next, an example of control by the ECU 20 will be described with reference to FIG. Also here, the description overlapping with FIG. 9 is omitted as much as possible.

  After the process of step ST2, the ECU 20 performs the current control cycle based on the steering torque T, the steering speed θ ′, the steering angle θ, and the torque differential value T ′ calculated in step ST2. Steering power P1 = θ ′ (t) · T (t) and steering power P2 = θ (t) · T ′ (t) are calculated. Then, the ECU 20 calculates the steering power P = A · P1 + B · P2 based on the calculated steering powers P1 and P2 and the preset coefficients A and B (step ST203).

  Next, the ECU 20 performs a low-pass filter (LPF) process on the calculation signal corresponding to the steering power P calculated in step ST203 (step ST204).

  Next, the ECU 20 calculates a torque gain based on the steering power P that has been subjected to the low-pass filter process in step ST204 (step ST205), and proceeds to the process of step ST7. For example, the ECU 20 calculates a torque gain from the steering power P based on the above-described torque gain map m2 (see FIG. 12).

  The driving assistance device 201 configured as described above has a case where the steering power corresponding to the product of the parameter related to the steering angle and the parameter related to the steering torque is equal to or higher than a preset reference value, When the value is smaller than the reference value, the control amount of the driving support by the support device 3, here, the target return control using the steering device 30 is changed. Thereby, the driving assistance apparatus 201 can implement | achieve the target return control which reflected the driver | operator's intention according to each, when an active operation is made, a passive operation is made, etc. That is, the driving support device 201 can perform driving support with less discomfort for the driver by reflecting the driver's operation intention in the target return control based on the steering power.

  Here, the driving assistance device 201 continues the target return control as usual when the steering power is smaller than the power reference value, while the steering power is higher than the work power when the steering power is equal to or higher than the power reference value. The target return control can be suppressed as compared with the case where it is smaller than the rate reference value. As a result, the driving support device 201 can suppress that the operation by the driver is restricted by the target return control when the driver performs an active operation on the steering 4, and the driver can comfortably operate. Hindering the steering operation can be suppressed. Further, when the driver performs a passive operation on the steering 4, the driving support device 201 can appropriately apply the steering wheel return torque by the target return control, and can make the operation by the driver easier. .

  The driving support device 201 and the ECU 20 according to the embodiment described above reflect the intention of the driver based on the steering power when the driver performs an active operation or when a passive operation is performed. In this case, the target return control can be realized. For example, it is possible to perform the driving support with less discomfort for the driver.

  In addition, the driving assistance apparatus and control apparatus which concern on embodiment of this invention mentioned above are not limited to embodiment mentioned above, A various change is possible in the range described in the claim. The driving support device and the control device according to the present embodiment may be configured by appropriately combining the components of the respective embodiments described above.

  In the above description, the control device of the driving support device has been described as being an ECU that controls each part of the vehicle. However, the present invention is not limited to this. For example, each control device is configured separately from the ECU and is mutually detected by the ECU. It may be configured to exchange information such as signals, drive signals, and control commands.

  In the above description, the steering device is a column assist type column EPS device. However, the present invention is not limited to this and can be applied to any of a pinion assist type and a rack assist type.

1,201 Driving support device 2 Vehicle 3 Support device 4 Steering (steering member)
5 Shaft (steering shaft)
8 EPS device 10 Steering angle sensor (steering angle detection device)
11 Torque sensor (torque detection device)
20 ECU (control device)
23, 223 Target return control unit 23a Steering speed target value calculation unit 23b Subtractor 23c P control amount calculation unit 23d Vehicle speed gain calculation unit 23e Differential calculation unit 23f, 223f Index calculation unit 23g Active / passive determination units 23h, 23k, 223g LPF
23i Torque gain calculating unit 23j Multiplier 23l Guard processing unit 23m First power calculating unit 23n Second power calculating unit 30 Steering device 40 Steering wheel 223h Passive operation gain calculating unit 223o Third power calculating unit

Claims (4)

A support device that performs driving support for a steering operation to a steering member of a vehicle;
A steering angle detection device for detecting a steering angle of the steering member;
A torque detection device that detects torque acting on a steering shaft that rotates together with the steering member;
A control device that controls the support device and is capable of executing a return control for assisting a switchback steering operation toward the neutral position side of the steering member;
The control device, when the steering power according to the product of the parameter related to the steering angle detected by the steering angle detection device and the parameter related to the torque detected by the torque detection device is greater than or equal to a preset reference value, The control amount of the return control is changed when the steering power is smaller than the reference value, and the torque detected by the torque detector is preset when the steering power is equal to or higher than the reference value. When the torque is equal to or greater than the predetermined torque, the control amount of the return control is relatively reduced as compared with the case where the steering power is smaller than the reference value . 2. The driving support device according to claim 1, wherein the control device changes a control amount of the return control according to the steering power when the steering power is smaller than the reference value. The control device continues the return control when the steering power is smaller than the reference value, while the steering power is smaller than the reference value when the steering power is equal to or higher than the reference value. it suppresses the return control in comparison with the driving support device according to claim 1 or 2, characterized in. The steering power is a product of a steering speed corresponding to the steering angle detected by the steering angle detection device and a torque detected by the torque detection device, or a steering angle detected by the steering angle detection device and the torque detection. driving support apparatus according to any one of claims 1 to 3 device is characterized in that it is calculated on the basis of either or both of the product of the torque differential value corresponding to the torque detected.

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