JP6631268B2 - Steering gear - Google Patents

Description

  The present invention relates to the technical field of a steer-by-wire steering device.

  Steer-by-wire steering devices are known. For example, Patent Document 1 discloses a steering device capable of changing a rotation ratio of a turning angle of a wheel to a steering angle of a steering member (for example, a steering wheel). In particular, Patent Document 1 discloses that the rotation ratio used when the vehicle is running automatically is made larger than the rotation ratio used when the vehicle is not running automatically, thereby reducing the movement of the steering member during the automatic running. A steering device to reduce is described.

JP 2004-224238 A

  The steering device described in Patent Literature 1 switches the rotation ratio when a vehicle that is automatically traveling ends automatic traveling or a vehicle that has not automatically traveled newly starts automatic traveling. However, when the rotation ratio is simply switched, after the rotation ratio is switched, the steering angle is zero but the turning angle is not zero (or the turning angle is zero). The steering angle is not zero). For example, if the rotation ratio of the turning angle to the steering angle is 2, the steering angle is +5 degrees, and the turning ratio is switched to 1 under the condition that the turning angle is +10 degrees, the steering member is only +5 degrees. Although the steering angle has become 0 degree by being returned, the turning angle has not become 0 degree (specifically, the turning angle has become +5 degree by returning the wheel by +5 degrees. Situation). As a result, a passenger operating the steering member may feel uncomfortable. On the other hand, by changing the turning angle or the steering angle at the same time as the switching of the rotation ratio, it is possible to satisfy the condition that the turning angle becomes zero when the steering angle becomes zero even after switching the rotation ratio. Switching the rotation ratio is theoretically possible. For example, assume that the rotation ratio of the turning angle to the steering angle is 2, the steering angle is +5 degrees, and the turning ratio is switched to 1 in a situation where the turning angle is +10 degrees. In this case, in order to switch the rotation ratio so as to satisfy the condition that the turning angle becomes zero when the steering angle becomes zero even after switching the rotation ratio, the steering angle is changed at the same time as the rotation ratio is switched. It is necessary to change from +5 degrees to +10 degrees or to change the turning angle from +10 degrees to +5 degrees. However, such a change in the steering angle or the turning angle may also give the occupant an uncomfortable feeling.

  The problems to be solved by the present invention include, for example, those described above. The present invention relates to a steer-by-wire system that can reduce a sense of discomfort given to a passenger when switching a relationship between a steering angle of a steering member and a turning angle of a wheel in accordance with switching of a traveling mode of a vehicle. It is an object to provide a steering device.

  A first aspect of a steering device according to the present invention is directed to a vehicle capable of switching a traveling mode between a manual mode in which the vehicle travels based on an operation of a passenger and an automatic mode in which the vehicle travels automatically without operation of the passenger. A steer-by-wire steering device for steering, wherein the steering member is operable by the occupant to turn the wheels of the vehicle and has the same posture every time the vehicle rotates a predetermined angle; and A first actuator that can drive the steering member so that the steering angle of the member becomes a first target angle; and a second actuator that can drive the wheel so that the turning angle of the wheel becomes a second target angle. Detecting means for detecting the steering angle and the turning angle; and a first function defining a correspondence relationship between the steering angle and the turning angle when the traveling mode of the vehicle is the manual mode. On the basis of the First calculating means for calculating the second target angle corresponding to the steering angle detected by the detecting means; and when the traveling mode of the vehicle is the automatic mode, the steering angle and the turning angle are calculated. Based on a second function that defines a correspondence relationship to be satisfied and the amount of change in the steering angle with respect to the turning angle is smaller than the first function, the second function corresponds to the turning angle detected by the detection unit. And a second calculating means for calculating the first target angle, wherein the first calculating means is configured to calculate the first target angle based on the first function when the traveling mode is switched from the automatic mode to the manual mode. Before calculating the second target angle, (i) a first condition that a correspondence between the steering angle and the turning angle detected by the detection unit at the timing when the traveling mode is switched is satisfied; ii) The turning angle is (B) a second condition that the attitude of the steering member is equal to the attitude of the steering member when the steering angle is zero; and (iii) the steering angle with respect to the steering angle. The detection means based on a third function defining a correspondence relationship between the steering angle and the turning angle so as to satisfy a third condition that a change tendency is most similar to a change tendency in the first function. Calculates the second target angle corresponding to the detected steering angle, and the second calculating means calculates the second target angle based on the second function when the traveling mode is switched from the manual mode to the automatic mode. Before calculating the first target angle by using the second function, (i) the first condition, (ii) the second condition, and (iii) the changing tendency of the turning snake angle with respect to the steering angle are determined by the second function. Most similar to the changing trend in The first target corresponding to the turning snake angle detected by the detection means based on a fourth function that defines a correspondence relationship that the steering angle and the turning snake angle should satisfy so as to satisfy a fourth condition of Calculate the angle.

  According to the first aspect of the steering device of the present invention, when the traveling mode is switched from the automatic mode to the manual mode, the third function is calculated before the second target angle is calculated based on the first function. The second target angle is calculated based on. Therefore, as compared with the case where the driving mode is switched from the automatic mode to the manual mode and the calculation of the second target angle based on the first function is started at the same time, the steering angle and the turning angle are changed in accordance with the switching of the driving mode of the vehicle. When switching the function that defines the correspondence with the steering angle, the discomfort given to the occupant is reduced. Similarly, when the traveling mode is switched from the manual mode to the automatic mode, the first target angle is calculated based on the fourth function before the first target angle is calculated based on the second function. . Therefore, as compared with the case where the driving mode is switched from the manual mode to the automatic mode and the calculation of the first target angle based on the second function is started at the same time, the steering member is steered in accordance with the switching of the driving mode of the vehicle. When the function that defines the correspondence between the angle and the turning angle of the wheel is switched, the discomfort given to the occupant is reduced.

FIG. 1 is a block diagram illustrating a configuration of the vehicle according to the first embodiment. FIG. 2 is a graph showing a steering function used in the first embodiment. FIG. 3 is a block diagram illustrating a configuration of the vehicle according to the second embodiment. FIG. 4 is a graph showing a steering function used in the second embodiment. FIG. 5 is a graph showing a steering function used in the second embodiment. FIG. 6 is a graph showing a steering function used in the second embodiment. FIG. 7 is a graph showing a steering function used in the second embodiment. FIG. 8 is a graph showing a steering function used in the second embodiment. FIG. 9 is a graph showing a steering function used in the second embodiment. FIG. 10 is a graph showing a steering function used in the second embodiment. FIG. 11 is a graph showing a steering function used in the second embodiment. FIG. 12 is a graph showing a steering function used in the second embodiment. FIG. 13 is a block diagram illustrating a configuration of the vehicle according to the third embodiment. FIG. 14 is a graph showing a steering function used in the third embodiment. FIG. 15 is a graph showing a steering function used in the third embodiment. FIG. 16 is a graph showing a steering function used in the third embodiment. FIG. 17 is a graph showing a steering function used in the third embodiment. FIG. 18 is a graph showing a steering function used in the third embodiment. FIG. 19 is a graph showing a steering function used in the third embodiment. FIG. 20 is a graph showing a steering function used in the third embodiment. FIG. 21 is a graph showing a steering function used in the third embodiment.

(1) First Embodiment Hereinafter, a vehicle 1 to which a first embodiment of a steering device of the present invention is applied will be described with reference to FIG. As shown in FIG. 1, the vehicle 1 includes wheels (turning wheels) 11 and a steering device 13 of a steer-by-wire system that can turn the wheels 11 (that is, can steer the vehicle 1).

  The steering device 13 includes a turning angle monitoring device 131 that is a specific example of a “detecting unit”, a target steering angle calculating unit 132 that is a specific example of a “second calculating unit”, and one of a “first actuator”. A steering actuator 133 as a specific example, a steering wheel 134 as a specific example of a “steering member”, a steering angle monitoring device 135 as a specific example of a “detecting unit”, and a specific example of a “first calculating unit” It includes a target turning angle calculation unit 136 as an example, a turning actuator 137 as a specific example of the “second actuator”, a running mode determination unit 138, and a function setting unit 139.

  The turning angle monitoring device 131 detects the turning angle θ of the wheel 11. The turning angle monitoring device 131 sends the detected turning angle θ (hereinafter, the turning angle θ detected by the turning angle monitoring device 131 is referred to as “turn angle θd”) to the target steering angle calculating section 132. Output. The target steering angle calculation unit 132 calculates a target steering angle φtg, which is a target value of the steering angle φ of the steering wheel 134, based on the turning angle θd. In particular, the target steering angle calculation unit 132 corresponds to the turning angle θd based on a steering function f (particularly, a steering function fa to be described later) that defines a correspondence relationship between the steering angle φ and the turning angle θ. The target steering angle φtg is calculated. The target steering angle calculation unit 132 outputs the calculated target steering angle φtg to the steering actuator 133. The steering actuator 133 rotates the steering wheel 134 so that the steering angle φ of the steering wheel 134 matches the target steering angle φtg.

  The steering wheel 134 is an operation member that can be operated (specifically, can be rotated) by a passenger to control the turning direction of the vehicle 1. The steering wheel 134 has a shape that becomes the same posture every time the steering wheel 134 is rotated by a predetermined angle. An example of such a shape is a shape in which the steering wheel 134 is symmetric with respect to a predetermined reference line passing through the center of rotation of the steering wheel 134. An example of a shape that becomes line symmetric is a shape such as the letter “H”. In this case, the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 180 degrees. An example of a line-symmetric shape is a shape such as the letter “T”. In this case, the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 360 degrees.

  The steering angle monitoring device 135 detects the steering angle φ of the steering wheel 134. The steering angle monitoring device 135 outputs the detected steering angle φ (hereinafter, the steering angle φ detected by the steering angle monitoring device 135 is referred to as “steering angle φd”) to the target turning angle calculation unit 136. The target turning angle calculation unit 136 calculates a target turning angle θtg, which is a target value of the turning angle θ, based on the steering angle φd. In particular, the target turning angle calculation unit 136 corresponds to the steering angle φd based on a steering function f (particularly, a steering function fm described later) that defines a correspondence relationship between the steering angle φ and the turning angle θ. The target turning angle θtg is calculated. The target rotatable angle calculating section 136 outputs the calculated target rotatable angle θtg to the rotatable actuator 137. The torsion actuator 137 turns and snakes the wheels 11 so that the torsion angle θ matches the target torsion angle θtg.

  The traveling mode determination unit 138 determines whether the traveling mode of the vehicle 1 is the automatic mode or the manual mode. Therefore, the vehicle 1 can travel in the automatic mode and can travel in the manual mode. The traveling mode determination unit 138 outputs the determination result to the function setting unit 139.

  The automatic mode is a traveling mode in which the vehicle 1 automatically travels without being based on an operation by the occupant (for example, an operation using the steering wheel 134, an accelerator pedal (not shown), a brake pedal (not shown), or the like). When the vehicle 1 is traveling in the automatic mode, the turning angle θ of the wheels 11 is set so that the vehicle 1 appropriately sets a desired traveling route (traveling locus) regardless of whether or not the passenger operates the steering wheel 134. The traveling is controlled by an automatic traveling control unit (not shown) (for example, a controller). Therefore, when the vehicle 1 is traveling in the automatic mode, the target turning / shake angle calculating unit 136 does not need to calculate the target turning / turning angle θtg based on the steering angle φd. For this reason, the snake actuator 137 snakes the wheel 11 under the control of the automatic traveling control unit instead of snaking the wheel 11 based on the target snake angle θtg. On the other hand, when the vehicle 1 is traveling in the automatic mode, the target steering angle calculation unit 132 calculates the target steering angle φtg based on the turning angle θd. Further, the steering actuator 134 rotates the steering wheel 134 based on the target steering angle φtg. As a result, the occupant can relatively easily recognize the turning direction (traveling direction) of the vehicle 1 running in the automatic mode from the movement of the steering wheel 134.

  The manual mode is a traveling mode in which the vehicle 1 travels based on a passenger's operation. When the vehicle 1 is traveling in the manual mode, the target turning / shake angle calculating unit 136 calculates the target turning / turning angle θtg based on the steering angle φd reflecting the operation result of the occupant. Further, the snake actuator 137 snakes the wheels 11 based on the target snake angle θtg. As a result, the turning angle θ of the wheels 11 is controlled according to the operation of the steering wheel 134 by the rider. On the other hand, when the vehicle 1 is traveling in the manual mode, the target steering angle calculation unit 132 does not have to calculate the target steering angle φtg based on the turning angle θd. Further, the steering actuator 134 does not have to rotate the steering wheel 134 based on the target steering angle φtg.

  The function setting unit 139 sets the steering function f. In particular, the function setting unit 139 sets the steering function f based on the determination result of the traveling mode determination unit 138.

  Specifically, when the vehicle 1 is traveling in the automatic mode, the function setting unit 139 determines the steering angle φ and the turning angle as the steering function f under the situation where the vehicle 1 is traveling in the automatic mode. A steering function fa that defines the correspondence that should be satisfied with θ is set. As described above, when the vehicle 1 is traveling in the automatic mode, the target steering angle φtg is calculated based on the steering angle θd, while the target steering angle θtg is calculated based on the steering angle φd. Is not calculated. Therefore, it can be said that the steering function fa is a steering function f that defines the correspondence between the turning angle θd and the target steering angle φtg. That is, it can be said that the steering function fa is a steering function f that the target steering angle calculation unit 132 should refer to when calculating the target steering angle φtg. When the function setting unit 139 sets the steering function fa as the steering function f, the target steering angle calculation unit 132 calculates the target steering angle φtg based on the steering function fa and the turning angle θd.

  On the other hand, when the vehicle 1 is traveling in the manual mode, the function setting unit 139 determines, as the steering function f, the steering angle φ and the turning angle θ in a situation where the vehicle 1 is traveling in the manual mode. A steering function fm that defines the correspondence that should be satisfied is set. As described above, when the vehicle 1 is traveling in the manual mode, the target turning angle θtg is calculated based on the steering angle φd, while the target steering angle φtg is calculated based on the turning angle θd. Is not calculated. Therefore, it can be said that the steering function fm is a steering function f that defines the correspondence between the steering angle φd and the target turning angle θtg. In other words, it can be said that the steering function fm is a steering function f that the target turning angle calculating section 136 should refer to for calculating the target turning angle θtg. When the function setting unit 139 sets the steering function fm as the steering function f, the target turning angle calculation unit 136 calculates the target turning angle θtg based on the steering function fm and the steering angle φd.

  The function setting unit 139 may store the steering functions fa and fm in advance. Each of the steering functions fa and fm may be appropriately calculated (generated) by the function setting unit 139.

Hereinafter, the steering functions fa and fm will be described in more detail with reference to FIG. As shown in FIG. 2, the steering function fa is specified by a relational expression “φ = fa (θ)”. Therefore, the target steering angle φtg is calculated from the relational expression “φtg = fa (θd)”. Further, the steering function fm is specified by a relational expression of “φ = fm (θ)”. Therefore, the target turning angle θtg is calculated from the relational expression “θtg = fm ⁻¹ (φd)”. In this embodiment, the unit of the angle is “degree”.

  In the example shown in FIG. 2, the steering function fa is a linear function. Specifically, in the example shown in FIG. 2, the relational expression of “φ = fa (θ)” is the relational expression of “φ = (180 / θmax) × θ”. Note that “θmax” is the maximum value (upper limit value) of the turning angle θ. For this reason, this relational expression means that when the vehicle 1 is running in the automatic mode, the steering wheel 134 rotates a half turn (rotates 180 degrees) when the wheels 11 are turned to the maximum extent. I have. However, the steering function fa shown in FIG. 2 is only an example. For this reason, a steering function fa different from the steering function fa shown in FIG. 2 may be used. For example, a steering function fa specified by a relational expression of “φ = (Ka / θmax) × θ (where Ka is an arbitrary constant)” may be used. For example, a steering function fa that is a non-linear function may be used.

  In the example shown in FIG. 2, the steering function fm is a linear function. Specifically, in the example shown in FIG. 2, the relational expression of “φ = fm (θ)” is the relational expression of “φ = (540 / θmax) × θ”. This relational expression indicates that, when the vehicle 1 is running in the manual mode, the wheel 11 is maximally turned when the occupant rotates the steering wheel 134 one rotation and a half turn (turns 540 degrees). Means However, the steering function fm shown in FIG. 2 is only an example. For this reason, a steering function fm different from the steering function fm shown in FIG. 2 may be used. For example, a steering function fm specified by a relational expression of “φ = (Km / θmax) × θ (where Km is an arbitrary constant)” may be used. For example, a steering function fm that is a non-linear function may be used.

  In the first embodiment, in particular, as shown in FIG. 2, the change amount of the steering angle φ with respect to the turning angle θ in the steering function fa is smaller than the change amount of the steering angle φ with respect to the turning angle θ in the steering function fm. . That is, the change amount Δφa of the steering angle φ with respect to the predetermined change amount Δθ of the turning angle θ in the steering function fa is smaller than the change amount Δφm of the steering angle φ with respect to the predetermined change amount Δθ of the turning angle θ in the steering function fm. . In other words, the gradient of the steering function fa (that is, Δφa / Δθ) is smaller than the gradient of the steering function fm (that is, Δφm / Δθ). As a result, when the vehicle 1 is traveling in the automatic mode, the rotation amount of the steering wheel 134 is smaller than when the vehicle 1 is traveling in the manual mode. Therefore, when the vehicle 1 is traveling in the automatic mode, the occupant can recognize the turning direction from the movement of the steering wheel 134 without being bothered by the movement of the steering wheel 134.

(2) Second Embodiment Next, a vehicle 2 to which a steering device according to a second embodiment of the present invention is applied will be described.

  In the first embodiment described above, when the traveling mode of the vehicle 1 is switched from the automatic mode to the manual mode, the steering function f is simultaneously switched from the steering function fa to the steering function fm. Similarly, when the traveling mode of the vehicle 1 is switched from the manual mode to the automatic mode, the steering function f is simultaneously switched from the steering function fm to the steering function fa. In this case, if the steering function f is simply switched, after the steering function f is switched, the turning angle θ is not zero, but the turning angle θ is not zero (or the turning angle θ). Is not zero, but the steering angle φ is not zero). Such a situation occurs when the steering function f is switched under a situation where the steering angle φ and the turning angle θ are not zero. That is, such a situation occurs when the steering function f is switched under a situation where the steering angle φ and the turning angle θ are different from the value corresponding to the intersection of the steering function fa and the steering function fm. Occurs. For example, in the example shown in FIG. 2, when the steering function f switches from the steering function fa to the steering function fm under a situation where the steering angle φ is φa (≠ 0) and the turning angle θ is θa (≠ 0). Is assumed. In this case, in order to maintain the continuity of the steering angle φ and the turning angle θ before and after the switching of the steering function f, the steering function f is switched to the steering function fm. And switching to a steering function fmp (see the relational expression indicated by the dotted line in FIG. 2) that passes through the coordinates (φa, θa). For this reason, as is clear from FIG. 2, the turning angle θ is not zero even though the steering angle φ is zero (or the steering angle φ is zero even when the turning angle θ is zero). Is not zero). Therefore, there is a possibility that a technical problem that a passenger operating the steering wheel 134 feels great discomfort may occur. In order to avoid such a situation from occurring, the steering function f switches from the steering function fa to the steering function fm under the condition that the steering angle φ is φa and the turning angle θ is θa, and at the same time, the steering angle φ Is also possible to switch from the steering angle φa corresponding to the steering function fa and the turning angle θa to the steering angle φm corresponding to the steering function fm and the turning angle θa. However, since the steering angle φ suddenly changes (that is, the steering wheel 134 suddenly rotates) with the switching of the steering function f, there is a technical problem that the occupant operating the steering wheel 134 feels great discomfort. It is still possible.

  The second embodiment of the steering device of the present invention suppresses the occurrence of such a technical problem that may occur when the steering function f is switched. Hereinafter, the vehicle 2 to which the second embodiment of the steering device of the present invention is applied will be described with reference to FIG. Note that the same components as those of the vehicle 1 described above are denoted by the same reference numerals, and a detailed description thereof will be omitted.

  As shown in FIG. 3, the vehicle 2 of the second embodiment is different from the vehicle 1 of the first embodiment in that the steering device 23 includes a function setting unit 239 instead of the function setting unit 139. Is different. Other components of the vehicle 2 may be the same as the other components of the vehicle 1.

  When the running mode of the vehicle 1 is switched from the manual mode to the automatic mode, the function setting unit 239 sets the steering function f to the steering function fm instead of switching the steering function f from the steering function fm to the steering function fa. Is switched to the steering function fa0. When the traveling mode of the vehicle 1 is switched from the automatic mode to the manual mode, the function setting unit 239 sets the steering function f to the steering function fa instead of switching the steering function f from the steering function fa to the steering function fm. Is switched to the steering function fm0. Hereinafter, the steering functions fa0 and fm0 will be described in more detail with reference to FIGS.

  FIG. 4 shows the steering function fm0. The steering function fm0 is a steering function f that satisfies the following three conditions (first condition, second condition, and third condition). That is, the steering function fm0 is a steering function f that defines a correspondence relationship between the steering angle φ and the turning angle θ to satisfy the following three conditions.

  The first condition is a correspondence relationship between the turning angle θd detected by the turning angle monitoring device 131 when the driving mode is switched and the steering angle φd detected by the steering angle monitoring device 135 when the driving mode is switched. Is satisfied. In the following description, the turning angle θd detected by the turning angle monitoring device 131 when the traveling mode is switched is referred to as “reference turning angle θ0”. Further, the steering angle φd detected by the steering angle monitoring device 135 at the time when the driving mode is switched is referred to as “reference steering angle φ0”. Therefore, the first condition is a condition that φ0 = fm0 (θ0) is satisfied. In other words, the first condition is a condition that the steering function fm0 is a function passing through the coordinates P1 (φ0, θ0).

  The second condition is a condition that makes it possible to make the attitude of the steering wheel 134 coincide with the attitude of the steering wheel 134 when the steering angle φ becomes zero under the condition that the turning angle θ becomes zero. Hereinafter, the attitude of the steering wheel 134 when the steering angle φ becomes zero is referred to as “first reference attitude”. Specifically, it is assumed that the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates a predetermined angle R. In this case, the attitude of the steering wheel 134 when the steering angle φ becomes zero, and the attitude and the steering angle φ of the steering wheel 134 when the steering angle φ becomes + k × R (k is an integer of 1 or more). Each of the postures of the steering wheel 134 when k × R is the first reference posture. Therefore, the second condition is a condition that 0 = fm0 (0), + k × R = fm0 (0) or −k × R = fm0 (0) is satisfied. In other words, the second condition is a condition that the steering function fm0 is a function passing through the coordinates (0, 0), the coordinates (+ k × R, 0), or the coordinates (−k × R, 0).

  FIG. 4 shows an example in which the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 360 degrees. In this case, the attitude of the steering wheel 134 when the steering angle φ becomes zero, the attitude of the steering wheel 134 when the steering angle φ becomes +360 degrees, and the attitude of the steering wheel 134 when the steering angle φ becomes -360 degrees. Are the first reference postures. Therefore, in the example shown in FIG. 4, the second condition is a condition that 0 degrees = fm0 (0), +360 degrees = fm0 (0) or −360 degrees = fm0 (0). In other words, the second condition is that the steering function fm0 is a function that passes through the coordinates P2 '' (0, 0), the coordinates P2 '(+360, 0), or the coordinates P2 (-360, 0).

  The third condition is that the changing tendency of the turning angle θ with respect to the steering angle φ in the steering function fm0 is most similar to the changing tendency of the turning angle θ with respect to the steering angle φ in the steering function fm. Here, the “change tendency” typically means the inclination of the steering function f. Therefore, the “state in which the change tendency of the steering function fm0 is most similar to the change tendency of the steering function fm” is typically a condition in which the sign of the slope of the steering function fm0 matches the sign of the slope of the steering function fm. Is satisfied, the inclination of the steering function fm0 is closest to the inclination of the steering function fm. " More specifically, “the state where the change tendency of the steering function fm0 is most similar to the change tendency of the steering function fm” is typically “the sign of the inclination of the steering function fm0 is equal to the sign of the inclination of the steering function fm. Under the condition that the condition of coincidence is satisfied, this means a state in which a steering angle φ2 described later is closest to a steering angle φ1 described later.

  A plurality of steering functions fm0 satisfying both the first and second conditions described above may exist. The third condition can specify one steering function fm0 actually used to calculate the target turning angle θtg from among the plurality of steering functions fm0. For example, in the example shown in FIG. 4, as the steering function fm0 satisfying both the first and second conditions, the steering function fm0-1 passing through the coordinate P1 (φ0, θ0) and the coordinate P2 (−360, 0), the coordinate A steering function fm0-2 passing through P1 (φ0, θ0) and coordinates P2 ′ (+360, 0), and a steering function fm0− passing through coordinates P1 (φ0, θ0) and coordinates P2 ″ (0, 0). 3 (= steering function fa) exists. Here, the changing tendency of the steering function fm0-1 is more similar to the changing tendency of the steering function fm as compared to the changing trends of the steering functions fm0-2 and fm0-3. Therefore, in the example shown in FIG. 4, the steering function fm0-1 is the steering function fm0 actually used for calculating the target turning angle θtg.

  The steering function fm0 that satisfies these three conditions is calculated by the function setting unit 239 according to the following procedure. First, the function setting unit 239 calculates a linear steering function fm ′ passing through the coordinates P1 (φ0, θ0) and having the same inclination as the steering function fm. Thereafter, the function setting unit 239 calculates a steering angle φ1 satisfying φ1 = fm ′ (0). That is, the function setting unit 239 calculates the steering angle φ1 corresponding to the coordinates of the intersection of the steering function fm ′ and the straight line defining the turning angle θ = 0. Thereafter, the function setting unit 239 calculates a steering angle φ2 which is closest to the steering angle φ1 and at which the attitude of the steering wheel 134 becomes the first reference attitude. In the example shown in FIG. 4, the steering angle φ2 is −360 degrees. Thereafter, the function setting unit 239 calculates a steering function fm0 passing through the coordinates P1 (φ0, θ0) and the coordinates P2 (φ2, 0).

  However, the steering function fm0 passing through the coordinates P1 (φ0, θ0) and the coordinates P2 (φ2, 0) surely satisfies the above-described first and second conditions, but does not satisfy the third condition (particularly, the steering operation). The sign of the slope of the function fm0 may not be the same as the sign of the slope of the steering function fm). If the calculated steering function fm0 does not satisfy the third condition, the function setting unit 239 newly sets the steering angle φ2 that is the second closest to the steering angle φ1 and the attitude of the steering wheel 134 is the first reference attitude. calculate. After that, the function setting unit 239 newly sets the steering function fm0 based on the newly calculated steering angle φ2. Thereafter, the function setting unit 239 repeats the same operation until the steering function fm0 satisfying the third condition is calculated.

  When the traveling mode of the vehicle 1 is switched from the automatic mode to the manual mode, the target turning angle calculation unit 136 first calculates the target turning angle θtg based on the steering function fm0. As a result, at the timing when the steering angle φ becomes φ2 (−360 degrees in FIG. 4), the attitude of the steering wheel 134 becomes the first reference attitude and the turning angle θ becomes zero. Therefore, a situation does not occur in which the attitude of the steering wheel 134 is not at the first reference attitude even though the turning angle θ is zero. The state where the attitude of the steering wheel 134 is the first reference attitude is substantially equivalent to the state where the steering angle φ is zero. Therefore, a situation does not occur in which the turning angle θ is not zero even when the steering angle φ is zero (that is, the attitude of the steering wheel 134 is the first reference attitude). In other words, a situation does not occur in which the steering angle φ is not zero even though the turning angle θ is zero (that is, the attitude of the steering wheel 134 is not the first reference attitude). Therefore, the steering device 23 can reduce a sense of discomfort that the passenger may have when the traveling mode is switched from the automatic mode to the manual mode (that is, the steering function f is switched).

  While the target turning angle calculation unit 136 is calculating the target turning angle θtg based on the steering function fm0, the turning angle θ may become zero. In this case, as shown in FIG. 5, the function setting unit 239 changes the steering function f from the steering function fm0 to the steering function having the same inclination as the steering function fm and passing through the coordinate P2 (φ2, 0). fm0 '. The operation of switching the steering function f to the steering function fm0 'substantially corresponds to the operation of switching the steering function f to the steering function fm. This is because a state in which both the steering angle φ and the turning angle θ are zero in the steering function fm is substantially equivalent to a state in which the steering angle φ is φ2 and the turning angle θ is zero in the steering function fm0 ′. This is because they are the same. Accordingly, the target turning angle calculation unit 136 can substantially calculate the target turning angle θtg based on the steering function fm. That is, in the second embodiment, when the traveling mode of the vehicle 1 is switched from the automatic mode to the manual mode, the target turning angle calculation unit 136 first calculates the target turning angle θtg based on the steering function fm0. Then, an operation of calculating the target turning angle θtg based on the steering function fm is performed.

  FIG. 6 shows the steering function fm0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fm0 shown in FIG. However, in the example shown in FIG. 6, the steering angle φ2 becomes zero. For this reason, the steering function fm0 matches the steering function fa.

  FIG. 7 shows the steering function fa0. Similarly to the steering function fm0, the steering function fa0 is a steering function f that satisfies the above-described first to third conditions. However, the third condition that the steering function fa0 satisfies is that, compared to the third condition that the steering function fm0 satisfies, the changing tendency of the turning angle θ with respect to the steering angle φ in the “steering function fa0” is The difference is that the condition is the most similar to the change tendency of the turning angle θ with respect to the steering angle φ. Accordingly, the steering function fa0 is determined by the above-described first and second conditions, and the tendency of the change of the turning angle θ with respect to the steering angle φ in the steering function fa0 is the changing tendency of the turning angle θ with respect to the steering angle φ in the steering function fa. It can be said that the steering function f satisfies the fourth condition that is most similar to the following.

  The function setting unit 239 calculates the steering function fa0 by performing the same procedure as that to be performed when calculating the steering function fm0. Specifically, the function setting unit 239 calculates a linear steering function fa ′ that passes through the coordinates P1 (φ0, θ0) and has the same inclination as the steering function fa. Thereafter, the function setting unit 239 calculates a steering angle φ1 satisfying φ1 = fa ′ (0). Thereafter, the function setting unit 239 calculates a steering angle φ2 which is closest to the steering angle φ1 and at which the attitude of the steering wheel 134 becomes the first reference attitude. Thereafter, the function setting unit 239 calculates a steering function fa0 passing through the coordinates P1 (φ0, θ0) and the coordinates P2 (φ2, 0).

  FIG. 7 shows an example in which the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 360 degrees. In the example shown in FIG. 7, the steering angle φ2 which is closest to the steering angle φ1 and in which the attitude of the steering wheel 134 is the first reference attitude should be originally +360 degrees. However, the sign of the slope of the steering function fa0 passing through the coordinates P1 (φ0, θ0) and the coordinate P2 (+360, 0) is not the same as the sign of the slope of the steering function fa. For this reason, 0 degree which is the second closest to the steering angle φ1 and in which the attitude of the steering wheel 134 is the first reference attitude is used as the steering angle φ2. Therefore, the steering function fa0 is a steering function f passing through the coordinates P1 (φ0, θ0) and the coordinates P2 (0, 0). In the example shown in FIG. 7, the steering function fa0 matches the steering function fm.

  When the traveling mode of the vehicle 1 is switched from the manual mode to the automatic mode, the target steering angle calculation unit 132 first calculates a target steering angle φtg based on the steering function fa0. As a result, at the timing when the steering angle φ becomes φ2 (0 degrees in FIG. 7), the attitude of the steering wheel 134 becomes the first reference attitude and the turning angle θ becomes zero. Therefore, a situation does not occur in which the attitude of the steering wheel 134 is not at the first reference attitude even though the turning angle θ is zero. Therefore, the steering device 23 can reduce a sense of discomfort that a passenger may have when the traveling mode is switched from the manual mode to the automatic mode (that is, the steering function f is switched).

  While the target steering angle calculator 132 calculates the target steering angle φtg based on the steering function fa0, the turning angle θ may become zero. In this case, the function setting unit 239 may switch the steering function f from the steering function fa0 to the steering function fa0 ′ having the same inclination as the steering function fa and passing through the coordinate P2 (φ2, 0). . The operation of switching the steering function f to the steering function fa0 'substantially corresponds to the operation of switching the steering function f to the steering function fa. Therefore, the target steering angle calculation unit 132 can substantially calculate the target steering angle φtg based on the steering function fa. That is, in the second embodiment, when the traveling mode of the vehicle 1 is switched from the manual mode to the automatic mode, the target steering angle calculation unit 132 first calculates the target steering angle φtg based on the steering function fa0. After that, the operation of calculating the target steering angle φtg based on the steering function fa is performed.

  FIG. 8 shows the steering function fa0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fa0 shown in FIG. FIG. 9 shows a situation where the coordinate P1 (φ0, θ0) is different from the steering function fm0 shown in FIG. 4, and the attitude of the steering wheel 134 is the same every time the steering wheel 134 rotates 180 degrees. 9 shows the steering function fm0 calculated under the following condition. FIG. 10 shows the steering function fm0 calculated in a situation where the coordinates P1 (φ0, θ0) are different from the steering function fm0 shown in FIG. FIG. 11 shows a situation where the coordinate P1 (φ0, θ0) is different from the steering function fa0 shown in FIG. 7, and the attitude of the steering wheel 134 is the same every time the steering wheel 134 rotates 180 degrees. 9 shows the steering function fa0 calculated under the following condition. FIG. 12 shows the steering function fa0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fa0 shown in FIG.

(3) Third Embodiment Next, a vehicle 3 to which a third embodiment of the steering device of the present invention is applied will be described.

  In the above-described second embodiment, the uncomfortable feeling that the occupant may have with the switching of the driving mode (switching of the steering function f) is reduced. On the other hand, in the second embodiment, the wheels 11 rotate to the maximum under a situation where the target turning angle θtg is calculated based on the steering function fm0 or the target steering angle φtg is calculated based on the steering function fa0. When the snake is turned (ie, the turning angle θ becomes θmax), the posture of the steering wheel 134 is different from the posture that the steering wheel 134 should take when the wheel 11 is turned to the maximum. There is a possibility that it will be. For example, in the example shown in FIG. 4, when the wheel 11 is turned to the maximum extent, the steering angle φ should be 540 degrees. However, when the wheel 11 is turned to the maximum extent under the condition that the target turning angle θtg is calculated based on the steering function fm0, the steering angle φ becomes 540 degrees (or 540 degrees ± 360 degrees × k). ). Therefore, there is a possibility that a technical problem that a passenger operating the steering wheel 134 feels great discomfort may occur.

  The third embodiment of the steering device of the present invention suppresses the occurrence of such a technical problem that may occur when the wheels 11 are turned to the maximum extent. Hereinafter, the vehicle 3 to which the third embodiment of the steering device of the present invention is applied will be described with reference to FIG. Note that the same components as those of the vehicle 2 described above are given the same reference numerals, and detailed description thereof will be omitted.

  As shown in FIG. 13, the vehicle 3 of the third embodiment is different from the vehicle 2 of the second embodiment in that the steering device 33 includes a function setting unit 339 instead of the function setting unit 239. Is different. Other components of the vehicle 3 may be the same as other components of the vehicle 2.

  The function setting unit 339 is different from the function setting unit 239 in that the set steering functions fm0 and fa0 are different from the steering functions fm0 and fa0 of the second embodiment, respectively. Hereinafter, the steering functions fa0 and fm0 of the third embodiment will be described in more detail with reference to FIGS.

  FIG. 14 shows the steering function fm0. Among the steering functions fm0, a steering function fm2 that defines a correspondence relationship between the steering angle φ and the steering angle θ within a range equal to or smaller than the reference steering angle θ0 is the same as the steering function fm0 of the above-described second embodiment. . Therefore, the steering function fm2 is a function that passes through the coordinates P1 (φ0, θ0) and the coordinates P2 (φ2, 0). On the other hand, among the steering functions fm0, the steering function fm4 that defines the correspondence relationship between the steering angle φ and the steering angle θ in a range equal to or greater than the reference steering angle θ0 is defined by the above-described first condition and the following. The steering function f satisfies two conditions (fifth condition and sixth condition).

  The fifth condition is a condition that makes it possible to make the attitude of the steering wheel 134 coincide with the second reference attitude under the situation where the turning angle θ becomes θmax. The second reference attitude is the attitude of the steering wheel 134 when the turning angle θ becomes θmax in a situation where the target turning angle θtg is calculated based on the steering function fm. Specifically, it is assumed that the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates a predetermined angle R. Here, in a situation where the target turning angle θtg is calculated based on the steering function fm, when the turning angle θ becomes θmax, the steering angle φ becomes φmax. In this case, the attitude of the steering wheel 134 when the steering angle φ becomes φmax, the attitude of the steering wheel 134 when the steering angle φ becomes φmax + k × R, and the steering wheel when the steering angle φ becomes φmax−k × R Each of the postures 134 is the second reference posture. Therefore, the fifth condition is a condition that φmax = fm4 (θmax), φmax + k × R = fm4 (θmax) or φmax−k × R = fm4 (θmax). In other words, the second condition is that the steering function fm4 is a function that passes the coordinates (φmax, θmax), (φmax + k × R, θmax) or the coordinates (φmax−k × R, θmax).

  FIG. 14 shows an example in which the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 360 degrees. Further, FIG. 14 shows an example in which the steering angle φ becomes 540 degrees when the wheel 11 is maximally turned while the target turning angle θtg is calculated based on the steering function fm. In this case, the attitude of the steering wheel 134 when the steering angle φ becomes 540 degrees, the attitude of the steering wheel 134 when the steering angle φ becomes +180 degrees, and the attitude of the steering wheel 134 when the steering angle φ becomes -180 degrees. Each of the attitude of the steering wheel 134 when the attitude and the steering angle φ become −540 degrees becomes the second reference attitude. Therefore, in the example shown in FIG. 14, the fifth condition satisfies +540 degrees = fm4 (θmax), +180 degrees = fm4 (θmax), −180 degrees = fm4 (θmax), or −540 degrees = fm4 (θmax). That is the condition. In other words, the fifth condition is that the steering function fm4 is such that the coordinate P3 (+180, θmax), the coordinate P3 ′ (−180, θmax), the coordinate P3 ″ (+540, θmax) or the coordinate P3 ′ ″ (−540, θmax). ).

  The sixth condition is a condition that the changing tendency of the turning angle θ with respect to the steering angle φ in the steering function fm4 is most similar to the changing tendency of the turning angle θ with respect to the steering angle φ in the steering function fm. There may be a plurality of steering functions fm4 that satisfy both the first and fifth conditions described above. The sixth condition can specify one steering function fm4 actually used to calculate the target turning angle θtg from among such a plurality of steering functions fm4. For example, in the example shown in FIG. 14, as the steering function fm4 satisfying both the first and fifth conditions, the steering function fm4-1 passing through the coordinate P1 (φ0, θ0) and the coordinate P3 (+180, θmax), and the coordinate P1 (Φ0, θ0) and a steering function fm4-2 passing through coordinates P3 ′ (−180, θmax), a steering function fm4-3 passing through coordinates P1 (φ0, θ0) and coordinates P3 ″ (+540, θmax), In addition, there is a steering function fm4-4 passing through the coordinates P1 (φ0, θ0) and the coordinates P3 ′ ″ (−540, θmax). Here, the changing tendency of the steering function fm4-1 is more similar to the changing tendency of the steering function fm as compared with the changing trends of the steering functions fm4-2 to fm4-4. Therefore, in the example shown in FIG. 14, the steering function fm4-1 is the steering function fm4 actually used to calculate the target turning angle θtg.

  The steering function fm4 that satisfies these three conditions is calculated by the function setting unit 339 according to the following procedure. First, the function setting unit 339 calculates the steering function fm 'described above. Thereafter, the function setting unit 339 calculates a steering angle φ3 that satisfies φ3 = fm ′ (θmax). Thereafter, the function setting unit 339 calculates a steering angle φ4 closest to the steering angle φ3 and at which the attitude of the steering wheel 134 becomes the second reference attitude. That is, the function setting unit 339 calculates the coordinates P3 (φ4, θmax). In the example shown in FIG. 14, the steering angle φ4 is +180 degrees. Thereafter, the function setting unit 339 calculates a steering function fm4 passing through the coordinates P1 (φ0, θ0) and the coordinates P3 (φ4, θmax).

  However, the steering function fm4 passing through the coordinates P1 (φ0, θ0) and the coordinates P3 (φ4, θmax) surely satisfies the above-described first and fifth conditions, but does not satisfy the sixth condition (particularly, the steering operation). The sign of the slope of the function fm4 may not be the same as the sign of the slope of the steering function fm). If the calculated steering function fm4 does not satisfy the sixth condition, the function setting unit 339 newly sets the steering angle φ4 that is the second closest to the steering angle φ3 and the attitude of the steering wheel 134 is the second reference attitude. calculate. After that, the function setting unit 339 newly sets the steering function fm4 based on the newly calculated steering angle φ4. Thereafter, the function setting unit 339 repeats the same operation until the steering function fm4 satisfying the sixth condition is calculated.

  When the traveling mode of the vehicle 1 is switched from the automatic mode to the manual mode, the target turning / shake angle calculating unit 136 firstly sets the target turning / shake angle θtg based on the steering function fm0 including the steering functions fm2 and fm4. Is calculated. As a result, the attitude of the steering wheel 134 becomes the second reference attitude at the timing when the wheels 11 are turned to the maximum extent. Therefore, the steering device 33 can alleviate the uncomfortable feeling that the occupant may have when the wheel 11 is turned to the maximum extent.

  FIG. 15 shows the steering function fm0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fm0 shown in FIG.

  FIG. 16 shows the steering function fa0. The steering function fa2 that defines the correspondence between the steering angle φ and the steering angle θ within the range of the reference steering angle θ0 or less in the steering function fa0 is the same as the steering function fa0 of the above-described second embodiment. . Therefore, the steering function fa2 is a function that passes through the coordinates P1 (φ0, θ0) and the coordinates P2 (φ2, 0). On the other hand, the steering function fa4 that defines the correspondence between the steering angle φ and the steering angle θ in the range of the reference steering angle θ0 or more of the steering function fa0 is the same as the first steering function fm4 described above. , A steering function f satisfying the fifth and sixth conditions. However, in the fifth condition that the steering function fa4 satisfies, the “target steering angle φtg” is calculated based on the “steering function fa” in the second reference attitude, as compared with the fifth condition that the steering function fm4 satisfies. This is different in that the steering wheel 134 is in the posture when the turning angle θ becomes θmax under the situation. Further, the sixth condition that the steering function fa4 satisfies is that, compared to the sixth condition that the steering function fm4 satisfies, the change tendency of the turning angle θ with respect to the steering angle φ in the “steering function fa4” The difference is that the condition is the most similar to the change tendency of the turning angle θ with respect to the steering angle φ. Therefore, the steering function fa4 is determined by the above-described first and fifth conditions and the change tendency of the turning angle θ with respect to the steering angle φ in the steering function fa4. This is the steering function f that satisfies the seventh condition that it is most similar to the tendency.

  The function setting unit 339 calculates the steering function fa4 by performing the same procedure as that to be performed when calculating the steering function fm4. Specifically, the function setting unit 339 calculates the above-described steering function fa '. Thereafter, the function setting unit 339 calculates a steering angle φ3 that satisfies φ3 = fa ′ (θmax). Thereafter, the function setting unit 339 calculates a steering angle φ4 which is closest to the steering angle φ3 and at which the attitude of the steering wheel 134 becomes the third reference attitude. Thereafter, the function setting unit 339 calculates a steering function fa4 passing through the coordinates P1 (φ0, θ0) and the coordinates P3 (φ4, θmax).

  FIG. 16 shows an example in which the attitude of the steering wheel 134 becomes the same every time the steering wheel 134 rotates 360 degrees. Further, FIG. 16 shows an example in which the steering angle φ becomes 180 degrees when the wheels 11 are turned to the maximum extent in a situation where the target turning angle θtg is calculated based on the steering function fa. In the example shown in FIG. 16, the steering angle φ4 that is closest to the steering angle φ3 and the attitude of the steering wheel 134 is the second reference attitude is +540 degrees. Therefore, the steering function fa4 is a steering function f passing through the coordinates P1 (φ0, θ0) and the coordinates P3 (+540, θmax).

  When the traveling mode of the vehicle 1 is switched from the manual mode to the automatic mode, the target steering angle calculation unit 132 first calculates the target steering angle φtg based on the steering function fa0 including the steering functions fa2 and fa4. I do. As a result, the attitude of the steering wheel 134 becomes the second reference attitude at the timing when the wheels 11 are turned to the maximum extent. Therefore, the steering device 33 can alleviate the uncomfortable feeling that the occupant may have when the wheel 11 is turned to the maximum extent.

  FIG. 17 shows the steering function fa0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fa0 shown in FIG. FIG. 18 shows a situation where the coordinate P1 (φ0, θ0) is different from the steering function fm0 shown in FIG. 14, and the attitude of the steering wheel 134 is the same every time the steering wheel 134 rotates 180 degrees. 9 shows the steering function fm0 calculated under the following condition. FIG. 19 shows the steering function fm0 calculated in a situation where the coordinates P1 (φ0, θ0) are different from the steering function fm0 shown in FIG. FIG. 20 shows a situation where the coordinates P1 (φ0, θ0) are different from those of the steering function fa0 shown in FIG. 16, and the attitude of the steering wheel 134 is the same every time the steering wheel 134 rotates 180 degrees. 9 shows the steering function fa0 calculated under the following condition. FIG. 21 shows the steering function fa0 calculated under the situation where the coordinates P1 (φ0, θ0) are different from the steering function fa0 shown in FIG. In the example shown in FIG. 21, the steering angle φ4 which is closest to the steering angle φ3 and the attitude of the steering wheel 134 is the second reference attitude should be originally +360 degrees. However, the sign of the inclination of the steering function fa4 passing through the coordinates P1 (φ0, θ0) and the coordinate P3 (+360, θmax) is not the same as the sign of the inclination of the steering function fa. Therefore, +540 degrees, which is the second closest to the steering angle φ3 and in which the attitude of the steering wheel 134 is the second reference attitude, is used as the steering angle φ4. Therefore, the steering function fa4 is a steering function f passing through the coordinates P1 (φ0, θ0) and the coordinates P3 (+540, θmax).

  The present invention can be appropriately modified without departing from the gist or the idea of the present invention which can be read from the claims and the entire specification, and a steering device with such a change is also included in the technical idea of the present invention. It is.

DESCRIPTION OF SYMBOLS 1, 2, 3 Vehicle 11 Wheel 13 Steering device 131 Steering angle monitoring device 132 Target steering angle calculating unit 133 Steer actuator 134 Steering wheel 135 Steering angle monitoring device 136 Target turning angle calculating unit 137 Swing actuator 139, 239, 339 Function setting section f, fm, fa, fm0, fa0 Steering function φ Steering angle φtg Target steering angle φ0 Reference steering angle θ Rolling angle θtg Target rolling angle θ0 Reference rolling angle

Claims (1)

A steer-by-wire steering device for steering a vehicle capable of switching a driving mode between a manual mode that runs based on an operation of a passenger and an automatic mode that runs automatically without an operation of the passenger. hand,
A steering member that is operable by the occupant to roll the wheels of the vehicle and that has the same posture each time the vehicle rotates a predetermined angle;
A first actuator that can drive the steering member so that the steering angle of the steering member becomes a first target angle;
A second actuator capable of driving the wheel so that the turning angle of the wheel becomes a second target angle;
Detecting means for detecting the steering angle and the turning angle,
When the traveling mode of the vehicle is the manual mode, the driving mode corresponds to the steering angle detected by the detection unit based on a first function that defines a correspondence relationship to be satisfied by the steering angle and the turning angle. First calculating means for calculating the second target angle;
When the traveling mode of the vehicle is the automatic mode, a change in the steering angle with respect to the steering angle is defined by defining a correspondence relationship between the steering angle and the steering angle and comparing with the first function. A second calculating means for calculating the first target angle corresponding to the turning angle detected by the detecting means, based on a second function that reduces the amount.
When the travel mode is switched from the automatic mode to the manual mode, the first calculation means may calculate (i) the travel mode before calculating the second target angle based on the first function. A first condition that the correspondence between the steering angle and the turning angle detected by the detection means is satisfied at the timing when the turning is switched, and (ii) the steering is performed under the condition that the turning angle becomes zero. The second condition that the posture of the member is equal to the posture of the steering member when the steering angle is zero, and (iii) the changing tendency of the turning snake angle with respect to the steering angle is represented by the first function. The steering angle corresponds to the steering angle detected by the detection means based on a third function that defines a correspondence relationship that the steering angle and the turning angle should satisfy so as to satisfy a third condition of being most similar to the change tendency. The second eye To calculate the corner,
When the traveling mode is switched from the manual mode to the automatic mode, the second calculating means may: (i) calculate the first target angle before calculating the first target angle based on the second function; And (iii) the second condition, and (iii) the steering angle so that the changing tendency of the turning angle with respect to the steering angle is most similar to the changing tendency in the second function. A steering function that calculates the first target angle corresponding to the turning angle detected by the detection unit, based on a fourth function that defines a correspondence relationship between the turning angle and the turning angle.

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