JP5992237B2 - Steering assist control device - Google Patents

Description

  The present invention relates to a steering assist for driving a traveling motor so that the steering can be easily performed in a vehicle equipped with a traveling motor capable of independently steering each wheel and independently driving each wheel. The present invention relates to a control device.

There is a turning device that turns each wheel independently (for example, Patent Document 1). In such an automobile with each wheel independently steered, there has also been proposed a vehicle in which all wheels are drive wheels and can be laterally moved and rotated on the spot. A vehicle in which each wheel can be steered independently and all wheels are drive wheels has an advantage that a special traveling form such as lateral movement or on-site rotation can be adopted.
In addition, a technique that utilizes the difference in driving force between the left and right driving wheels for steering a vehicle has been proposed (for example, Patent Documents 2 and 3).

JP 2012-45989 A JP-A 48-44914 Japanese Patent Application No. 2005-178527

Many of the above-described steering devices that independently steer each wheel have a large kingpin offset, which is a distance from the point where the kingpin centerline, which is the steering centerline, intersects the road surface to the ground contact center of the tire. When this kingpin offset is large, the load of the steering drive source becomes large at the time of turning, so that the capacity of the turning drive source becomes large and the turning device becomes large.
Therefore, in the vehicle provided with the above-described steering device, it was considered to assist the steering by applying a driving force to the left and right driving wheels. However, appropriate steering assist cannot be performed unless the drive mode such as the rotation direction and torque of the driving motor for the drive wheels driven for the steering assist is set correctly. In particular, if the direction of rotation of the traveling motor is not correct, the steering load will be increased.

  An object of the present invention is to provide a steering assist control device that can appropriately perform quick steering while suppressing an increase in the load of a steering drive source even in a vehicle using a steering device having a large kingpin offset. .

The steering assist control device of the present invention includes three or more wheels 1 and 2, a steering device 4 that can steer each of the wheels 1 and 2 independently, and performs steering by each of the steering drive sources 10, A steering motor 6 for independently driving the wheels 1 and 2; and a steering control means 32 for controlling the steering drive source 10 based on an input signal from a steering input means 51; 4 is a steering assist control apparatus for a vehicle having a kingpin offset L1, the so steered during the that by the turning device 4 steering is facilitated the run line motor 6 of the wheels 2 The steering assist drive means 35 controls the output of the travel motor 6, and the drive assist drive means 35 has a plurality of drive modes for driving the travel motor 6. The turning of the steering device 4 is determined. Depending on the circumstances, by selecting the drive mode, wherein the TURMERIC line control of the output. The “steering status of the steering device 4” means the degree of load acting on the steering drive source 10 of the steering device 4 and what kind of steering input to the steering device 4. And a combination of modes before and after mode switching when a travel mode to be described later is set. The “drive mode” refers to the rotational direction and the magnitude of torque of the traveling motor 6 as described later, for example.

  According to this configuration, the steering assist driving means 35 controls the output of the traveling motor 6 of each of the wheels 1 and 2 so that the steering is promoted during the steering by the steering device 4. Even in a vehicle using the steering device 4 having a large kingpin offset L1, an increase in the load of the steering drive source 10 can be suppressed and rapid steering can be performed. Further, regarding the control of this output, the steering assist driving means 35 has a plurality of driving modes for driving the traveling motor 6, and depends on the steering situation of the steering device 4. Since the drive mode is selected and the output is controlled, appropriate steering assistance can be performed.

  One of the plurality of types of driving modes is the rotational direction of each traveling motor 6 and the magnitude of the torque of each traveling motor 6. When assisting the turning by the output of the traveling motor 6, if the rotational direction of the traveling motor 6 is not appropriate, the load of the turning is increased and the turning state of the turning device 4 is increased. Accordingly, by appropriately selecting the rotation direction of the traveling motor 6, appropriate steering assistance can be performed. Further, since it is considered that the appropriate torque value of the traveling motor 6 for assisting the steering differs depending on the combination of modes before and after the switching, the rotation direction of the traveling motor 6 is set depending on the combination of the modes before and after the switching. In addition, it is preferable to set the torque of the traveling motor 6 for proper steering.

In the present invention, as a mode for driving the vehicle, a normal mode that is a mode in which the vehicle travels forward and backward, a parking mode in which the vehicle is stopped, and the left and right wheels 1 and 2 are steered in opposite directions to each other. , 2 is a lateral movement mode in which the vehicle runs sideways with respect to the vehicle, and the left and right wheels 1, 1, 2, 2 are steered in opposite directions, and all the wheels 1, 2 are inclined with respect to the vehicle. Mode setting means 34a for setting the in-situ rotation mode for rotating the vehicle around the center of the vehicle as the steering assist drive means 35 for each mode combination before and after switching when switching the mode, Of the driving modes, the rotational direction of each of the traveling motors and the magnitude of torque may be determined.
When switching the travel mode, the vehicle is steered, and the vehicle is largely steered in a stationary state where the travel is stopped. It is preferable to assist the rudder. However, in the configuration in which the steering in various modes as described above can be performed, the driver determines which direction of rotation of the traveling motor 6 for assisting the steering is to be performed and how the magnitude of the torque is to be determined. Is difficult to determine during operation. In this regard, if the rotation direction and the magnitude of torque of each traveling motor 6 for assisting the steering are determined for each combination of modes before and after the switching, it is only necessary to select the mode after the switching. The direction of rotation and the magnitude of torque of the traveling motor 6 for assisting the rudder are correctly determined.

In the present invention, the selection of the rotation direction of the traveling motor 6 and the magnitude of the torque by the steering assist driving means 35 may be performed based on an input signal from the steering input means 51. The steering input means 51 is a steering wheel, a joystick, an operation button, or the like. When the steering input means 51 is operated, the direction in which the driver wants to steer is determined. Therefore, by using the information, the rotation direction of the traveling motor 6 for steering assist is correctly determined. Further, when the steering angle of the steering wheel is large or when the rate of change of the steering angle is large, the turning angle becomes large and the turning speed becomes fast, so that the driving time and load of the turning drive source 10 become large. However, by determining the magnitude of the torque so that the torque for assisting the steering by the traveling motor 6 is increased, the steering can be quickly performed even if the steering drive source 10 has a small rated output. It can be carried out. In particular, when the steering input means 51 is operated while the vehicle is stopped, the load of the steering drive source 10 increases, so that the steering assist is provided by the driving force of the left and right wheel driving motors 6. By doing so, the effect of speeding up the steering is great.
Even when the mode setting means 34a for setting the normal mode, the parking mode, the lateral movement mode, and the spot rotation mode is provided, the steering input means 51 is operated in the normal mode. It is preferable that selection of the rotation direction of the traveling motor 6 and the magnitude of torque by the assist driving unit 35 is performed based on an input signal from the steering input unit 51. Also in this case, the effect of the steering assist by the driving force of the traveling motor 6 is great at the time of stationary.

In the present invention, the direction and torque determined according to the detected value of the load of the steering drive source 10 for the selection of the rotational direction and torque magnitude of the traveling motor 6 by the steering assist drive means 35. May be selected.
When the steered drive source 10 is operated, a load is generated in the steered drive source 10, and the direction of the load can be detected from the current of the steered drive source 10 such as a servo motor. By determining the rotation direction of the traveling motor 6 in the direction in which the load is reduced from the detected load direction, the rotation direction of the traveling motor 6 for the steering assist is correctly determined. Further, by detecting the load of the steering drive source 10 composed of a servo motor or the like, the degree of margin of the steering drive source 10 can be known. Therefore, according to the detected value of the load of the steering drive source 10, when the margin of the steering drive source 10 is small, the torque for the steering assist of the traveling motor 6 is increased and the margin of the steering drive source 10 is increased. When is large, more appropriate steering assist can be performed by reducing the torque for the steering assist of the traveling motor 6.
Also in this case, when the steering input means 51 is operated while the vehicle is stopped, the load of the steering drive source 10 increases, so that the steering force of the left and right wheels is driven by the driving force of the driving motor 6 for the left and right wheels. By performing the assist, the effect of speeding up the steering is great.
Even in the case where the mode setting means 34a for setting each mode is provided, in the normal mode, the turning direction and the magnitude of the torque are not determined until the turning is started by the input of the steering input means 51. Therefore, in order to perform the steering assist by driving the traveling motor 6, it is necessary to determine the rotational direction of the traveling motor 6 and the magnitude of the torque. In this case, by selecting the direction and the magnitude of torque determined according to the detected value of the load of the turning drive source 10, the rotational direction and the magnitude of the torque of the traveling motor 6 for turning assistance are selected. Is correctly defined.

In the present invention, as one of the plurality of types of drive modes to be selected, only the magnitude of the torque of the traveling motor 6 may be used. If the torque of the traveling motor 6 for turning assistance can be set appropriately, turning assistance can be performed more appropriately.
In the case of including the mode setting means for setting each mode, it is preferable to include the magnitude of the torque of the traveling motor 6 as one of the plurality of types of driving modes to be selected in the normal traveling mode. . Since the rotational direction of the traveling motor 6 has already been determined during normal traveling, the torque may be increased or decreased with respect to the rotational direction.

  In the present invention, the traveling motor 6 may be the motor 6 constituting the in-wheel motor driving device 5. When the in-wheel motor driving device 5 is used, the degree of freedom of all-wheel steering and driving mode by all-wheel driving is increased, but there is a disadvantage that a portion to be steered by the steering device 4 is large and heavy. By using the steering assist control device, it is possible to appropriately perform quick steering while suppressing an increase in the load of the steering drive source 10.

The steering assist control device according to the present invention includes three or more wheels, a steering device that can independently steer each wheel and that steers by a steering drive source, and drives each wheel independently. A steering assist control device for a vehicle, comprising: a traveling motor; and a steering control unit that controls the steering drive source based on an input signal from a steering input unit, wherein the steering device has a kingpin offset. , comprising a steering assist drive means performs the control of the output of the run-row motors of the wheels as steered during turning by the turning device is facilitated, the steering assist drive means, the travel For controlling the output of the motor for driving, a plurality of driving modes for driving the traveling motor are defined, and the driving mode is selected according to the steering situation of the steering device, and the output control is performed. the line song Me, King Even in a vehicle emissions offset using the large turning device, it is possible to properly carry out rapid steered suppressing an increase in the steering drive source load.

It is a top view which shows arrangement | positioning of the drive system and steering system of a vehicle to which the steering assist control apparatus which concerns on one Embodiment of this invention is applied. It is explanatory drawing which showed the block diagram which shows the structure of the control system of the vehicle on the top view of FIG. It is the side view and sectional view which show an example of the steering device of the vehicle. Perspective and explanatory view of an operation direction of an example of the joystick is the steering input means in the same vehicle. It is explanatory drawing of each mode of the vehicle. It is explanatory drawing which shows the rotation direction of the motor for driving | running | working at the time of the mode change of the vehicle.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing an arrangement of a drive system and a steering system of an electric vehicle that is a vehicle equipped with a steering assist control device according to this embodiment. This automobile is a four-wheeled vehicle provided with two left and right wheels 1 and 1 as front wheels and two right and left wheels 2 and 2 as rear wheels. A steering device 4 that can be steered independently is provided. These steered devices 4 are steer-by-wire types that are not mechanically connected to the steering input means. Each of the wheels 1 and 2 is a driving wheel in the illustrated example, and is independently driven by an in-wheel motor driving device 5 including a driving motor 6.

  The in-wheel motor drive device 5 includes a wheel bearing 7 that supports the wheels 1 and 2, the traveling motor 6 that includes an electric motor, and the wheel bearing that decelerates the rotation output from the traveling motor 6. 7 and a speed reducer 8 that transmits the rotation side raceway ring (not shown). The traveling motor 6 is a synchronous motor such as an IPM motor in this example, but may be an induction motor or a direct current motor. The in-wheel motor drive device 5 includes the wheel bearing 7, the drive source 6, and the speed reducer 8 that are installed in a common housing or coupled together to be integrated. The integrated in-wheel motor drive device 5 is installed in the vehicle body 3 so as to be rotatable around the turning center axis 20 in the vertical direction via the turning device 4 and the suspension 40.

  As shown in FIG. 3, the in-wheel motor drive device 5 incorporates braking means 35 that is disposed inside the rim W of the wheels 1 and 2 and brakes the rim W. In the figure, the illustration of the traveling motor and the speed reducer of the in-wheel motor drive device 5 is omitted. The in-wheel motor drive device 5 has a part of the housing serving as a hub carrier 14, and has an upper staple 14 a and a lower stay 14 b that protrude inward in the vehicle body width direction above and below the hub carrier 14.

  The upper stay 14a is connected to the tip of the upper arm 41 of the suspension 40 via an upper joint 43 provided at the tip. The lower stay 14b is connected to the tip of the lower arm 42 of the suspension 40 via a lower joint 44 provided at the tip. A straight line passing between the centers of the upper joint 43 and the lower joint 44 becomes a kingpin center line K of the suspension 40. The distance from the point where the kingpin center line K intersects the road surface to the ground contact center of the tires of the wheels 1 and 2 is the kingpin offset L1. In this example, the point at which the kingpin center line K intersects the road surface has a large kingpin offset L1 that is a position away from the tire.

  In this example, the upper joint 43 includes an upper arm 41 and a T-shaped member 45 provided at the tip of the upper arm 41. The T-shaped member 45 includes a shaft-like horizontal member 45a extending in the horizontal direction and a vertical member 45b protruding from the center in the length direction of the horizontal member 45a. The horizontal member 45a is disposed so that the length direction thereof faces the longitudinal direction of the vehicle body with respect to a bracket provided at the tip of the upper arm 41, and is supported rotatably. Therefore, the vertical member 45b can swing with respect to the vehicle body width direction. The center line of the vertical member 45b coincides with the kingpin center line K. The vertical member 45 b functions as the turning center axis 20 in the vertical direction of the turning device 4.

  The steered device 4 has a steered drive source 10 composed of a motor such as a servomotor. The output shaft 11 of the steering drive source 10 is connected to a worm 13 supported by a gear case 12 via a rotation transmission mechanism (not shown) including a gear train, and the worm 13 is connected to the turning center shaft 20. Is engaged with a worm wheel 21 fixed to the outer periphery of the worm wheel. The gear case 12 is fixed to the hub carrier 14 and is rotatable with respect to the worm wheel 21.

  For this reason, when the worm 13 is rotated by the drive of the turning drive source 10, the worm 13 receives a reaction force from the worm wheel 21 and rotates around the turning center axis 20 together with the gear case 12. By this rotation, the wheels 1 and 2 are steered.

  This automobile has a structure including the steering mechanism 4 in which all the wheels 1 and 2 can be independently steered, and a structure in which all the wheels 1 and 2 can be independently driven. ) And a non-normal traveling mode that is an in-situ rotation mode or a lateral movement mode illustrated in FIGS. 5B and 5C, respectively. Moreover, it is possible to take the parking mode of FIG.

  The in-situ rotation form in FIG. 5B is a moving form in which the vehicle body 3 is rotated on the spot (rotation radius is substantially zero) around the center of the vehicle body 3. Specifically, the in-situ rotation mode is such that the wheels 1 and 2 are directed in a direction along a common virtual circumference C (that is, a tangential direction), and the wheels 1 and 2 that are driving wheels are As seen from the center O side of the circumference, this is a moving form in which they are rotationally driven in the same direction as indicated by arrows in the figure. Therefore, the left and right wheels 1, 1, 2, 2 are steered in the opposite directions from the straight traveling direction. The in-situ rotation mode can be rotated in either the left or right direction by switching the rotation direction of the wheels 1 and 2 that are drive wheels to forward and reverse.

  The lateral movement mode in FIG. 5C is a movement mode in which the vehicle body 3 is moved in a direction just beside or close to the beside. Specifically, the lateral movement mode is a mode in which the wheels 1 and 2 are turned sideways with respect to the vehicle body 3 and the wheels 1 and 2 serving as driving wheels are rotated so as to roll in the same lateral direction. Although the change from the straight traveling state to the lateral movement mode depends on the configuration of the steering mechanism 4, in this example, the turning angle is not simply increased, but the front wheel 1 in FIG. As shown in the middle of turning, the left and right wheels 1 and 1 are turned in opposite directions so as to be line targets with each other, so that the wheels 1 and 1 are turned sideways. The same applies to the rear wheels 2 and 2. In this way, when the wheels are steered and moved in the lateral direction, the left and right wheels 1, 1, 2, and 2 are opposite to each other when the wheels 1 and 2 that are the drive wheels are rotated to roll in the same lateral direction. Will be driven to rotate.

  In the parking mode of FIG. 5 (D), the left and right wheels 1 and 1 that are front wheels have a turning angle that opens to the front, and the left and right wheels 2 and 2 that become rear wheels have a turning angle that opens to the back. Stop the vehicle. Each turning angle may be, for example, about 45 °, or may be an angle at which the wheels 1 and 2 are directed radially with the center of the vehicle body 3 as the radial center. By parking the front and rear wheels 1, 1, 2, and 2 as left and right turning angles as described above, it is possible to prevent the vehicle from moving unexpectedly during parking due to a slope of the road surface or the like.

  The normal traveling mode of FIG. 5 (A) is a normal straight traveling or traveling in a curved line direction of the arc, and is a traveling mode other than the in-situ rotating mode and the laterally moving mode. In the normal travel mode, the left and right wheels 1, 1, 2 and 2 are steered in the same direction.

  In FIG. 1, the driving operation system will be described. A seat serving as a driver's seat 11 and a passenger seat 12 is provided in the passenger compartment 3a of the vehicle body 3. As a driving operation system, a joystick 51 serving also as a steering input means and an accelerator operating means, and a brake operator 56 are provided. Is provided. The brake operator 56 includes a brake pedal and the like, and is provided on the floor portion in front of the driver's seat 11.

The joystick 51 is a general term for input operation means that can input both the direction and the operation amount with a single operator touched by the driver. In this embodiment, for example, a lever-type joystick 51 shown in FIG. 4 is provided. ing. The joystick 51 can be operated by tilting the lever 51a, which is a manipulator, in an arbitrary direction of 360.degree. From the upright state where the lever 51a is in the neutral position. The joystick 51 is provided with various operation buttons 52 to 55 . In this example, the joystick 51 is installed on the dashboard 24 in front of the driver's seat 11 via a joystick installation seat as shown in FIG.

An example of operation input of the joystick 51 is as follows.
(In normal mode)
The torque of the traveling motor 6 is designated by the operation amount of the front / rear operation. When the joystick 51 is completely tilted forward, the maximum torque is generated in the forward direction. Moreover, when it is tilted completely backward, the maximum torque is generated in the reverse direction.
It should be noted that an accelerator operation amount (corresponding to a pedal-type accelerator depression amount) can be input according to a tilt amount of the joystick 51 (a tilt angle from a neutral position).
The turning angle of the steering device is specified by the operation amount of the left / right operation. When the joystick 51 is completely tilted to the right, the turning angle of the tire becomes an angle determined to the right. Further, when the joystick 51 is completely tilted leftward, the turning angle of the tire becomes an angle determined to the left. The “fixed angle” is set as appropriate.
The steering amount (corresponding to the operation angle of a general passenger car handle) can be input according to the amount of tilt of the joystick 51 (the angle of tilt from the neutral position).

(In case of in-situ rotation mode)
The amount of operation for front and back operations is ignored.
The torque of the traveling motor 6 is designated by the operation amount of the left / right operation. When the joystick 51 is completely tilted to the right, the maximum clockwise torque is generated. Further, when it is completely tilted to the left, the maximum counterclockwise torque is generated.
It should be noted that an accelerator operation amount (corresponding to a pedal-type accelerator depression amount) can be input according to a tilt amount of the joystick 51 (a tilt angle from a neutral position).

(When in horizontal movement mode)
The amount of operation for front and back operations is ignored.
The torque of the traveling motor 6 is designated by the operation amount of the left / right operation. When the joystick 51 is completely tilted to the right, the maximum torque in the right direction is generated. Moreover, when it is tilted completely to the left, the maximum torque in the left direction is generated.
It should be noted that an accelerator operation amount (corresponding to a pedal-type accelerator depression amount) can be input according to a tilt amount of the joystick 51 (a tilt angle from a neutral position).

(When in parking mode)
The amount of operation for front and back operations is ignored.
The amount of left / right operation is also ignored.

  The steering input means may be a steering wheel (not shown) instead of the joystick 51. Further, the accelerator operation means may be an accelerator pedal instead of the joystick 51.

The control system will be described with reference to FIG. ECU31 is overall control of the automobile, an electric control unit for cooperative control, consisting microcontroller Pew capacitor and the electronic circuit. The ECU 31 may be composed of a plurality of ECUs classified by function. Here, the ECU 31 will be described as a group of the plurality of ECUs. The ECU 31 includes a steering control unit 32, a travel drive control unit 33, a mode switching control unit 34, and a steering assist drive unit 35.

  The turning control means 32 receives a steering direction signal from the turning input means, in the illustrated example, the steering direction signal input by the joystick 51, and issues a drive command to the turning drive source 10 of each turning device 4. It is a means to give.

  The travel drive control means 33 is a drive command such as a torque command to the inverter device 39 of the travel motor 6 of each wheel in accordance with the accelerator operation amount of the accelerator operation means, in the illustrated example, the accelerator operation amount signal input by the joystick 51. Is a means for outputting. The accelerator operation amount signal is an acceleration command, a deceleration command, or a speed maintenance command.

  The inverter device 39 includes an inverter that changes DC power of a battery (not shown) into AC power for driving the traveling motor 6 and an electronic circuit that controls the inverter.

  The mode switching control means 34 is a means for selecting a traveling mode by switching between a normal mode, a parking mode, a lateral movement mode, and an in-situ rotation mode by a mode switching signal. The mode switching signal is input to the ECU 31 from a combination of a plurality of button operations provided on a dedicated mode switching operation means, for example, the joystick 51.

The mode switching control unit 34 has a mode setting unit 34a in which commands for turning and driving are set for each mode, and commands in the selected mode set in the mode setting unit 34a. And output to the steering control means 32 and the travel drive control means 33.
The setting contents in each mode of the mode setting unit 34a will be described.
In the in-situ rotation mode, as described above with reference to FIG. 5B, a command for turning the steered device 4 of each wheel, a rotation direction of each traveling motor 6, and a torque command value are set. The torque command value is a constant value, for example.
In the lateral movement mode, as described above with reference to FIG. 5C, a command for turning the steered device 4 of each wheel, a rotation direction of each traveling motor 6, and a torque command value are set. The torque command value is a constant value, for example.
In the normal mode, the steering and traveling commands are not set in particular, and the input signals input from the steering input means such as the joystick 51 and the accelerator input means are used as they are for the steering control means 32 and the traveling drive control means 33. Give to.
In the parking mode, as described above with reference to FIG. 5D, a command for turning the steering device 4 of each wheel is set.

  In FIG. 2, the steering assist driving means 35 is a means for controlling the output of the traveling motor 6 for each of the wheels 1 and 2 so that the steering is promoted during the turning by the steering device 4. A plurality of drive modes for driving the traveling motor 6 are determined for the steering assist drive means 35 to control the output, and the drive mode is determined according to the state of the steering of the steering device 4. To control the output. The “driving mode for driving the traveling motor 6” here refers only to the rotation direction of the traveling motor 6 and the magnitude of the torque or the magnitude of the torque. The “steering status of the steering device” means the degree of load acting on the steering drive source of the steering device and what kind of steering input is given to the steering device 4. And a combination of modes before and after mode switching when a driving mode described later is set.

  The steering assist driving means 35 selects a driving mode according to the steering situation detection unit 35a for detecting the steering situation of the steering device 4 and the steering situation detected by the steering situation detection unit 35a. And a situation corresponding drive unit 35b for controlling the output of the traveling motor 6.

  In this embodiment, the steering assist driving means 35 has the following functions. The turning assist driving means 35 determines the rotation direction and torque magnitude of each traveling motor 6 for each combination of modes before and after switching when switching the modes set in the mode switching setting means 34a. Yes. As a specific example, FIG. 6 shows an example of the rotation direction of one traveling motor 6. As shown in FIG. 6, the case where the normal mode is switched to the lateral movement mode, the parking mode, and the in-situ rotation mode is shown. In addition, the rotation direction of the traveling motor 6 when switching from an arbitrary mode to another arbitrary mode is set. In the figure, the mode is set to the clockwise direction in the mode switching connected by the solid arrow, and the counterclockwise direction is set in the mode switching connected by the dashed arrow. The magnitude of the torque sets the rotational direction of the traveling motor 6 when switching from an arbitrary mode to another arbitrary mode, and the magnitude of the torque of the traveling motor 6 when each of these switching is performed. This is also set.

  When switching the travel mode, the vehicle is steered, and the vehicle is largely steered in a stationary state where the travel is stopped. It is preferable to assist the rudder. As a result, even in a vehicle using the steering device 4 having a large kingpin offset L1, an increase in the load of the steering drive source 10 can be suppressed and rapid steering can be performed. However, in the configuration in which the steering in various modes as described above can be performed, the driver determines which direction of rotation of the traveling motor 6 for assisting the steering is to be performed and how the magnitude of the torque is to be determined. Is difficult to determine during operation. In this regard, if the rotation direction and the magnitude of torque of each traveling motor 6 for assisting the steering are determined for each combination of modes before and after the switching, it is only necessary to select the mode after the switching. The direction of rotation and the magnitude of torque of the traveling motor 6 for assisting the rudder are correctly determined.

  Further, the steering assist driving means 35 performs the following control. The direction of rotation of the traveling motor 6 and the magnitude of torque are selected based on the input signal from the steering input means 51. This control is applied when the normal mode is selected when the mode setting means 34a is provided as described above. The steering input means 51 is a steering wheel, a joystick, an operation button, or the like.

When the steering input means 51 is operated, the direction in which the driver wants to steer and the steering angle are determined. Therefore, by using this information, the rotational direction and torque of the traveling motor 6 for steering assist can be determined. The size is correctly determined. In particular, when the steering input means 51 is operated while the vehicle is stopped, the load of the steering drive source 10 increases, so that the steering assist is provided by the driving force of the left and right wheel driving motors 6. By doing so, the effect of speeding up the steering is great.
Even when the mode setting means 34a for setting the normal mode, the parking mode, the lateral movement mode, and the spot rotation mode is provided, the steering input means 51 is operated in the normal mode. Selection of the direction of rotation of the traveling motor 6 and the magnitude of torque by the assist drive means 35 can be performed based on an input signal from the steering input means 51. Also in this case, the effect of the steering assist by the driving force of the traveling motor 6 is great at the time of stationary.

Instead of the configuration in which the rotation direction and torque magnitude of the traveling motor 6 by the steering assist driving means 35 are selected based on the input signal from the steering input means 51, the load of the steering drive source 10 is changed. The rotational direction and the magnitude of torque may be determined according to the detected value.
When the steered drive source 10 is operated, a load is generated in the steered drive source 10, and the direction and magnitude of the load can be detected from the current of the steered drive source 10 such as a servo motor. By determining the rotation direction of the traveling motor 6 in the direction in which the load is reduced from the detected load direction, the rotation direction of the traveling motor 6 for the steering assist is correctly determined. Further, the degree of margin of the steering drive source 10 can be found from the magnitude of the load. Therefore, more appropriate turning assist can be performed by changing the magnitude of the torque in accordance with the detected value of the load of the turning drive source 10.
Also in this case, when the steering input means 51 is operated while the vehicle is stopped, the load of the steering drive source 10 increases, so that the steering force of the left and right wheels is driven by the driving force of the driving motor 6 for the left and right wheels. By performing the assist, the effect of speeding up the steering is great.
Even in the case where the mode setting means 34a for setting each mode is provided, in the normal mode, the turning direction and the magnitude of the torque are not determined until the turning is started by the input of the steering input means 51. Therefore, in order to perform the steering assist by driving the traveling motor 6, it is necessary to determine the rotational direction of the traveling motor 6 and the magnitude of the torque. In this case, by determining the direction and the magnitude of the torque determined according to the detected value of the load of the turning drive source 10, the rotational direction and the magnitude of the torque of the traveling motor 6 for turning assistance are determined. Is correctly defined.

In the above description, the rotation direction of the traveling motor 6 and the selection of the magnitude of the torque have been described. However, only the magnitude of the torque of the traveling motor 6 may be selected as the drive mode to be selected.
When the mode setting means 34a for setting each mode is provided, the rotational direction of the traveling motor 6 has already been determined when traveling in the normal traveling mode, so the torque may be increased or decreased with respect to the rotational direction. .

  For example, the steering assist driving means 35 determines the magnitude of the torque of the traveling motor 6 by an input signal from a joystick 51 as the steering input means. The steering input means may be a steering wheel, an operation button, or the like. When the steering angle of the joystick 51 or the steering wheel is large, or when the rate of change of the steering angle is large, the driving time and load of the steering drive source 10 are increased. By increasing the torque, even if the turning drive source 10 has a small rated output, the turning can be performed quickly.

  The steering assist drive means 35 determines the magnitude of the torque of the traveling motor 6 according to the detected value of the load of the steering drive source 10 instead of determining the magnitude of the torque by the input signal of the steering input means. Also good. By detecting the load of the steering drive source 10 composed of a servo motor or the like, the degree of margin of the steering drive source 10 can be determined. Therefore, according to the detected value of the load of the steering drive source 10, when the margin of the steering drive source 10 is small, the torque for the steering assist of the traveling motor 6 is increased and the margin of the steering drive source 10 is increased. When is large, more appropriate steering assist can be performed by reducing the torque for the steering assist of the traveling motor 6.

  Moreover, in the said embodiment, although the motor 6 for driving | running | working was set to the motor 6 which comprises the in-wheel motor drive device 5, when the in-wheel motor drive device 5 is used, freedom of the travel mode by all-wheel steering and all-wheel drive is possible. Although the degree increases, there is a disadvantage that a portion to be steered by the steering device 4 is large and heavy, but by using the steering assist control device of the present invention, an increase in the load of the steering drive source 10 can be suppressed quickly. Can be properly steered.

  The present invention is not limited to a vehicle in which the traveling motor 6 constitutes the in-wheel motor drive device 5, and is installed on the chassis to the wheels 1 and 2 via a drive transmission system such as a drive shaft and a constant velocity joint. The present invention can also be applied to a vehicle that transmits rotation. Further, the present invention can be applied not only to a four-wheel vehicle but also to a three-wheel, six-wheel, etc. vehicle.

DESCRIPTION OF SYMBOLS 1, 2 ... Wheel 3 ... Car body 4 ... Steering device 5 ... In-wheel motor drive device 6 ... Traveling motor 7 ... Wheel bearing 8 ... Reduction gear 10 ... Steering drive source 14 ... Hub carrier 20 ... Steering center axis 21 ... Worm wheel 31 ... ECU
32 ... Steering control means 33 ... Traveling drive control means 34 ... Mode switching control means 34a ... Mode setting means 35 ... Steering assist driving means 40 ... Suspension 51 ... Joystick (steering input means)
K ... Kingpin center line L1 ... Kingpin offset

Claims (6)

From three or more wheels, a steering device that can steer each wheel independently and steer by each steering drive source, a traveling motor that drives each wheel independently, and a steering input means A steering control means for controlling the steering drive source based on an input signal, the steering assist control device in a vehicle in which the steering device has a kingpin offset,
Comprising a steering assist drive means performs the control of the output of the run-row motors of the wheels as steered at by that turning the steering equipment is promoted, the steering assist drive means, For controlling the output of the traveling motor, a plurality of driving modes for driving the traveling motor are defined, and the driving mode is selected according to the situation of the steering of the steering device. steering assist control apparatus characterized the TURMERIC line control of the output. In Claim 1, as the mode for running the vehicle, a normal mode in which the vehicle travels forward and backward, a parking mode for stopping the vehicle, and the left and right wheels are steered in opposite directions to all the wheels in the vehicle. On the other hand, a lateral movement mode in which the vehicle travels sideways as a sideways direction, and an in-situ rotation mode in which the left and right wheels are steered in opposite directions and the vehicle is rotated around the center of the vehicle with all wheels being oblique to the vehicle. And mode setting means for setting
The steering assist drive means determines the rotation direction of each driving motor and the magnitude of the torque of each driving motor for each combination of modes before and after switching when switching the mode. A steering assist control device.   3. The steering assist control according to claim 1, wherein the steering assist driving means determines a rotation direction of the traveling motor and a magnitude of torque of the traveling motor by an input signal from the steering input means. apparatus.   3. The steering assist driving means according to claim 1, wherein the steering assist driving means determines a rotation direction of the traveling motor and a magnitude of torque of the traveling motor according to a detected value of a load of the steering driving source. Steering assist control device.   3. The steering assist control device according to claim 2, wherein the plurality of types of driving modes selected are magnitudes of torques of the respective traveling motors.   6. The steering assist control device according to claim 1, wherein the traveling motor is a motor that constitutes an in-wheel motor drive device.

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