JP2017001562A - Steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve cost reduction while maintaining safety in a steering control device having a steer-by-wire structure.SOLUTION: A steering control device comprises: a first steering shaft 3 which is rotated in association with steering operation by an operator; a second steering shaft 4 which is connected to a rack shaft 5 for steering a wheel 2; a clutch 6 for changeover between connection and disconnection of the first steering shaft 3 and the second steering shaft 4; steering motors 31, 36 which give a steering force onto the rack shaft 5 in the state that the clutch 6 is disconnected; and a reaction force motor 41 which gives a reaction force onto the steering shaft 3 in the state that the clutch 6 is disconnected. The reaction force motor 41 can give an assist force for assisting steering operation by the operator onto the first steering shaft 3 in the state the clutch 6 is connected.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steering control device.

  Patent Document 1 discloses a steering control having a steer-by-wire structure that drives and controls a first steering motor and a second steering motor according to a steering command value and drives and controls a reaction force motor according to a reaction force command value. An apparatus is disclosed.

  The steering control device disclosed in Patent Document 1 mechanically connects the steering system by connecting a clutch when an abnormality occurs in the control system of the second steering controller that controls the driving of the second steering motor. Then, assist control by the first turning motor is executed to reduce the operation burden on the driver.

JP 2014-156151 A

  Generally, a steering control device having a steer-by-wire structure has two steered motors for driving, as in Patent Document 1, and there is an abnormality in one of the control systems that control the drive of each steered motor. Even if it occurs, a steerable motor that can be driven is secured, and the safety is high. However, having two steering motors causes an increase in the cost of the steering control device.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to reduce costs while maintaining safety in a steering control device having a steer-by-wire structure.

  The first invention includes a connection switching unit that switches connection and disconnection between the first steering shaft and the second steering shaft, a steering motor that applies a steering force to the rack shaft in a state where the connection switching unit is disconnected, A reaction force motor that applies a steering reaction force to the first steering shaft in a state in which the connection switching unit is disconnected, and the reaction force motor allows a driver to perform a steering operation in a state in which the connection switching unit is connected. An assisting force to assist can be applied to the first steering shaft.

  In the first invention, the reaction force motor applies a steering reaction force to the first steering shaft in a state in which the connection switching unit is disconnected, and applies an assist force to the first steering shaft in a state in which the connection switching unit is connected. It can be granted. Thus, the reaction force motor has two functions.

  In the second invention, when an abnormality occurs in the steering motor or the system that controls the steering motor, the connection switching unit is connected, and the reaction force motor has an assist force that assists the steering operation by the driver. It is provided to the first steering shaft.

  In the second invention, the reaction force motor applies a steering reaction force to the first steering shaft in a normal state, and performs assist control when an abnormality occurs in the steering motor or the system that controls the steering motor. Therefore, the cost can be reduced while maintaining safety.

  The third invention further includes a torque sensor for detecting a steering torque input by a steering operation by the driver, and when an abnormality occurs in the steering motor or a system for controlling the steering motor, the connection switching unit is In addition to being connected, the reaction force motor is characterized in that an assist force for assisting the steering operation by the driver is applied to the first steering shaft based on the detection result of the torque sensor.

  In 3rd invention, even if it is a case where abnormality generate | occur | produces in the steering motor or the system which controls a steering motor, stable assist control can be performed.

  The fourth invention is characterized in that there is only one steering motor.

  In the fourth invention, the cost can be reduced.

  According to a fifth aspect of the present invention, the steered motor includes a plurality of systems having a motor coil and a controller that drives the motor coil.

  In the fifth invention, since two or more drive systems are secured even at the time of fail safe, safety can be improved.

  According to the present invention, in a steering control device having a steer-by-wire structure, it is possible to reduce costs while maintaining safety.

1 is a configuration diagram of a steering control device according to a first embodiment of the present invention. FIG. It is a block diagram of the steering control apparatus which concerns on 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
A steering control apparatus 100 according to a first embodiment of the present invention will be described with reference to FIG.

  The steering control device 100 assists steer-by-wire control in which the wheel 2 is steered in accordance with the operation state of the steering wheel 1 by the driver and the operation of the steering wheel 1 by the driver (hereinafter referred to as “steering operation”). Both the assist control and the assist control are possible.

  The steering control device 100 includes a first steering shaft 3 that rotates in response to a steering operation by a driver, a second steering shaft 4 that is connected to a rack shaft 5 that steers the wheel 2, a first steering shaft 3, and a first steering shaft 3. 2 and a clutch 6 as a connection switching unit for switching between connection and disconnection with the steering shaft 4.

  The clutch 6 is an electromagnetic clutch, which cuts the first steering shaft 3 and the second steering shaft 4 when the electromagnetic coil is excited, and mechanically connects the first steering shaft 3 and the second steering shaft 4 when the electromagnetic coil is not excited. Connect to. Steer-by-wire control is performed when the clutch 6 is disconnected, and assist control is performed when the clutch 6 is connected.

  The second steering shaft 4 connects the input shaft 11 connected to the clutch 6, the pinion shaft 12 formed with the pinion gear 12 a meshing with the rack gear 5 a formed on the rack shaft 5, and the input shaft 11 and the pinion shaft 12. And a torsion bar 13.

  When the steering wheel 1 is operated with the clutch 6 connected, the first steering shaft 3 and the second steering shaft 4 rotate, and the rotation is converted into linear motion by the pinion gear 12a and the rack gear 5a, and the knuckle arm The wheel 2 is steered via 14.

  The first steering shaft 3 is provided with a steering angle sensor 21 that detects a steering angle that is a rotation angle of the steering wheel 1. Although not shown, the rudder angle sensor 21 includes a center gear that rotates integrally with the first steering shaft 3 and two outer gears that mesh with the center gear, and is based on a change in magnetic flux accompanying the rotation of the two outer gears. Thus, the rotation angle of the center gear, that is, the rotation angle of the first steering shaft 3 is calculated.

  The second steering shaft 4 is provided with a torque sensor 22 that detects a steering torque input by a driver's steering operation when the clutch 6 is connected. The torque sensor 22 detects the steering torque based on the torsional deformation of the torsion bar 13 accompanying the relative rotation between the input shaft 11 and the pinion shaft 12.

  The steering control device 100 applies a steering reaction force to the first steering shaft 3 while the steering motor 31 applies a steering force to the rack shaft 5 with the clutch 6 disconnected, and the clutch 6 is disconnected. A reaction force motor 41.

  The driving force of the steered motor 31 is output to the pinion shaft 12 with the rotational speed reduced by the speed reduction mechanism 32. Therefore, when the first turning motor 31 is driven in a state where the clutch 6 is disconnected, a turning force for turning the wheel 2 is applied to the rack shaft 5 through the pinion shaft 12. Further, when the first turning motor 31 is driven in a state where the clutch 6 is connected, an assist force that assists the steering operation by the driver is applied to the pinion shaft 12. The speed reduction mechanism 32 includes a worm shaft 32 a connected to the output shaft of the steering motor 31, and a worm wheel 32 b that meshes with the worm shaft 32 a and is connected to the pinion shaft 12.

  The driving force of the reaction force motor 41 is output to the first steering shaft 3 with the rotational speed reduced by the speed reduction mechanism 42. When the reaction force motor 41 is driven with the clutch 6 disengaged, a steering reaction force is applied to the first steering shaft 3 in response to the driver's steering operation. As a result, a pseudo steering wheel weight can be given to the driver's steering operation. The speed reduction mechanism 42 includes a worm shaft 42 a connected to the output shaft of the reaction force motor 41, and a worm wheel 42 b that meshes with the worm shaft 42 a and is connected to the first steering shaft 3.

  The steering control device 100 further includes a steering controller 35 that controls the driving of the steering motor 31 and a reaction force controller 45 that controls the driving of the reaction force motor 41. The steered controller 35 and the reaction force controller 45 are connected to each other via a communication line 50 so that they can communicate with each other. In addition to the detection signal of the steering angle sensor 21 and the detection signal of the torque sensor 22, vehicle state information such as the vehicle speed is input to the steering controller 35 and the reaction force controller 45.

  Next, steering control by the steering control device 100 will be described.

  Normally, the clutch 6 is disengaged and steer-by-wire control is performed. In the steer-by-wire control, the steering controller 35 controls the steering motor 31 according to the operation state of the steering wheel 1 to steer the wheels 2. Specifically, the steering controller 35 sets a target turning angle based on the detection result of the steering angle sensor 21 and the vehicle speed, and the steering motor so that the turning angle of the wheel 2 matches the target turning angle. 31 is controlled. Further, in the steer-by-wire control, the reaction force controller 45 controls the reaction force motor 41 according to the steered state of the wheel 2 and applies a steering reaction force to the steering wheel 1. Specifically, the reaction force controller 45 sets a target steering reaction force corresponding to the reaction force received from the road surface by the steering operation, and the steering reaction force applied to the first steering shaft 3 matches the target steering reaction force. Thus, the reaction force motor 41 is controlled.

  When each of the steering controller 35 and the reaction force controller 45 determines that there is an abnormality in its own control system, the clutch 6 is connected and the steering control is switched from the steer-by-wire control. The clutch 6 switches from the disconnected state to the connected state when an abnormality occurs in any of the control systems of the steering controller 35 and the reaction force controller 45. Here, the control system is a system that controls the steered motor 31 including the steered motor 31 and the steered controller 35 itself in the case of the steered controller 35, and the reaction system in the case of the reaction force controller 45. This system controls the reaction force motor 41 including the force motor 41 and the reaction force controller 45 itself.

  When the reaction force controller 45 determines that there is an abnormality in its own control system, the abnormality information is transmitted from the reaction force controller 45 to the steering controller 35 and the clutch 6 is connected. The steered controller 35 controls the steered motor 31 based on the detection result of the torque sensor 22 so that an assist force for assisting the steering operation by the driver is applied to the pinion shaft 12. At this time, the reaction force motor 41 is disconnected from the reaction force controller 45 so as not to be a load for the steering operation, and is in a no-load state. Thus, when abnormality occurs in the reaction force motor 41 or the system that controls the reaction force motor 41, assist control by the steered motor 31 is performed.

  On the other hand, when the steering controller 35 determines that there is an abnormality in its own control system, the abnormality information is transmitted from the steering controller 35 to the reaction force controller 45 and the clutch 6 is connected. The reaction force controller 45 controls the reaction force motor 41 based on the detection result of the torque sensor 22 such that an assist force that assists the steering operation by the driver is applied to the first steering shaft 3. At this time, the steered motor 31 is disconnected from the steered controller 35 so as not to be a load for the steering operation and is in a no-load state. Thus, when abnormality occurs in the steering motor 31 or the system that controls the steering motor 31, assist control by the reaction force motor 41 is performed. The driving force of the reaction force motor 41 is output to the first steering shaft 3 with the rotational speed reduced by the speed reduction mechanism 42 so that the assist control by the reaction force motor 41 is possible.

  According to the above 1st Embodiment, there exists an effect shown below.

  The reaction force motor 41 normally performs steer-by-wire control that applies a steering reaction force to the steering wheel 1. On the other hand, if an abnormality occurs in the steering motor 31 or the system that controls the steering motor 31, the first steering wheel Assist control for applying assist force to the shaft 3 is performed. That is, the reaction force motor 41 has two functions. Thus, since the reaction force motor 41 functions as an assist motor that performs assist control at the time of fail-safe, the steering control device 100 is safe even though the number of steered motors is only one. Sex is secured. Therefore, the cost can be reduced while maintaining safety.

  Below, the modification of the said 1st Embodiment is demonstrated.

  (1) In the first embodiment, the steered motor 31 is connected to the pinion shaft 12 connected to the steering wheel 1. Instead of this, in addition to the pinion shaft 12, a second pinion shaft that meshes with the rack gear 5a formed on the rack shaft 5 may be provided, and the steered motor 31 may be connected to the second pinion shaft. That is, it may be a dual pinion type having two pinion shafts.

  (2) The first embodiment is configured to be switched from steer-by-wire control to assist control during fail-safe. Instead of this, a configuration may be adopted in which the steering control is switched from the steer-by-wire control to the assist control by a driver's operation even during normal times.

  (3) In the first embodiment, the steered motor 31 may be a fault tolerant motor including a plurality of systems having a motor coil and a controller that drives the motor coil. If the steered motor 31 is configured in this way, two or more drive systems are secured even during fail-safe, and safety can be improved.

Second Embodiment
A steering control device 200 according to a second embodiment of the present invention will be described with reference to FIG. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to FIG. 2 and the same structure as the said 1st Embodiment, and description is abbreviate | omitted.

  Although there is one steering motor in the first embodiment, the steering control device 200 according to the second embodiment is different from the first embodiment in that it includes two steering motors. This will be specifically described below.

  The steering control device 200 applies a steering force to the rack shaft 5 in a state where the clutch 6 is disconnected, in addition to the first steering motor 31 and the first steering controller 35 having the same configuration as the first embodiment. And a second turning controller 37 for controlling the driving of the second turning motor 36. The first turning controller 35, the second turning controller 37, and the reaction force controller 45 are connected to each other via a communication line 50 so that they can communicate with each other.

  The steering control device 200 further includes a second pinion shaft 16 in addition to the first pinion shaft 12 having the same configuration as that of the first embodiment. The second pinion shaft 16 has a second pinion gear 16 a that meshes with a rack gear 5 a formed on the rack shaft 5. Thus, the steering control device 200 is a dual pinion type having two pinion shafts.

  The driving force of the second turning motor 36 is output to the second pinion shaft 16 with the rotational speed reduced by the speed reduction mechanism 38. Therefore, when the second turning motor 36 is driven in a state where the clutch 6 is disconnected, a turning force for turning the wheel 2 is applied to the rack shaft 5 through the second pinion shaft 16. Further, when the second steering motor 36 is driven with the clutch 6 connected, an assist force that assists the steering operation by the driver is applied to the rack shaft 5 through the second pinion shaft 16. The speed reduction mechanism 38 has a worm shaft 38 a connected to the output shaft of the second steering motor 36, and a worm wheel 38 b that meshes with the worm shaft 38 a and is connected to the second pinion shaft 16.

  Next, steering control by the steering control device 200 will be described.

  Normally, the clutch 6 is disengaged and steer-by-wire control is performed. In the steer-by-wire control, the first turning controller 35 controls the first turning motor 31 according to the operation state of the steering wheel 1, and the second turning controller 37 depends on the operation state of the steering wheel 1. The second steering motor 36 is controlled. Thereby, the wheel 2 is steered. The first turning motor 31 and the second turning motor 36 share the necessary turning force and output it. The reaction force motor 41 applies a steering reaction force to the first steering shaft 3 as in the first embodiment.

  The clutch 6 switches from a disconnected state to a connected state when an abnormality occurs in any of the control systems of the first steering controller 35, the second steering controller 37, and the reaction force controller 45.

  When the reaction force controller 45 determines that there is an abnormality in its own control system, the abnormality information is transmitted from the reaction force controller 45 to the first steering controller 35 and the second steering controller 37 and the clutch 6 Is connected. The first turning controller 35 is configured so that the first turning motor 31 applies an assisting force to the first pinion shaft 12 for assisting the steering operation by the driver based on the detection result of the torque sensor 22. 31 is controlled. Further, the second turning controller 37 performs the second turning so that the second turning motor 36 applies an assisting force to the second pinion shaft 16 for assisting the steering operation by the driver based on the detection result of the torque sensor 22. The rudder motor 36 is controlled. The first turning motor 31 and the second turning motor 36 share the necessary assist force and output it. Thus, even when an abnormality occurs in the reaction force motor 41 or the system that controls the reaction force motor 41, the assist control by the first turning motor 31 and the second turning motor 36 is performed, and two The above drive system is secured.

  On the other hand, when the first turning controller 35 determines that there is an abnormality in its own control system, the abnormality information is transmitted from the first turning controller 35 to the second turning controller 37 and the reaction force controller 45. At the same time, the clutch 6 is connected. Based on the detection result of the torque sensor 22, the second steering controller 37 provides the second steering motor 36 with an assist force that assists the steering operation by the driver to the second pinion shaft 16. 36 is controlled. Further, the reaction force controller 45 controls the reaction force motor 41 based on the detection result of the torque sensor 22 so that the reaction force motor 41 provides the first steering shaft 3 with an assist force that assists the steering operation by the driver. . The second turning motor 36 and the reaction force motor 41 share the required assist force and output it. Thus, even if an abnormality occurs in the first steering motor 31 or the system that controls the first steering motor 31, assist control by the second steering motor 36 and the reaction force motor 41 is performed. Two or more drive systems are secured.

  Similarly, even when an abnormality occurs in the second turning motor 36 or the system that controls the second turning motor 36, the assist control by the first turning motor 31 and the reaction force motor 41 is performed. More than one drive system is secured.

  According to the above 2nd Embodiment, there exists an effect shown below.

  The reaction force motor 41 normally performs steer-by-wire control that applies a steering reaction force to the steering wheel 1, while an abnormality occurs in the first steering motor 31 or the system that controls the first steering motor 31, and When an abnormality occurs in the second steering motor 36 or the system that controls the second steering motor 36, assist control for applying an assist force to the first steering shaft 3 is performed. That is, the reaction force motor 41 has two functions. Thus, since the reaction force motor 41 functions as an assist motor that performs assist control during fail-safe, two or more drive systems are ensured even during fail-safe. Therefore, safety can be improved despite the fact that the number of steering motors is two, which is the same as the conventional number. Therefore, safety can be improved without increasing the cost. In other words, the cost can be reduced while maintaining safety.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  In the present embodiment, the first steering shaft 3 that rotates in accordance with the steering operation by the driver, the second steering shaft 4 that is connected to the rack shaft 5 that steers the wheels 2, the first steering shaft 3, and the second steering shaft 3. The clutch 6 that switches connection and disconnection of the steering shaft 4, the steering motors 31 and 36 that apply a steering force to the rack shaft 5 in a state where the clutch 6 is disconnected, and a state where the clutch 6 is disconnected A reaction force motor 41 for applying a steering reaction force to the steering shaft 3, and the reaction force motor 41 provides an assist force for assisting a steering operation by the driver in a state where the clutch 6 is connected to the first steering shaft. 3 can be granted.

  In this configuration, the reaction force motor 41 applies a steering reaction force to the first steering shaft 3 when the clutch 6 is disconnected, and applies an assist force to the first steering shaft 3 when the clutch 6 is connected. Is possible. Thus, the reaction force motor 41 has two functions. Therefore, in the steering control device 100 having the steer-by-wire structure, the cost can be reduced while maintaining safety.

  In this embodiment, when an abnormality occurs in the steering motors 31, 36 or the system that controls the steering motors 31, 36, the clutch 6 is connected and the reaction force motor 41 is steered by the driver. An assist force for assisting the operation is applied to the first steering shaft 3.

  In this configuration, the reaction force motor 41 normally applies a steering reaction force to the first steering shaft 3, while an abnormality occurs in the steering motors 31, 36 or the system that controls the steering motors 31, 36. Performs assist control. Therefore, the cost can be reduced while maintaining safety.

  Further, in the present embodiment, the torque sensor 22 that detects the steering torque input by the steering operation by the driver is further provided, and an abnormality has occurred in the steering motors 31, 36 or the system that controls the steering motors 31, 36. In this case, the clutch 6 is connected, and the reaction force motor 41 applies to the first steering shaft 3 an assist force that assists the steering operation by the driver based on the detection result of the torque sensor 22.

  In this configuration, stable assist control can be performed even when an abnormality occurs in the steering motors 31 and 36 or the system that controls the steering motors 31 and 36.

  In this embodiment, there is only one steering motor.

  With this configuration, the cost can be reduced.

  In the present embodiment, the steered motors 31 and 36 include a plurality of systems having a motor coil and a controller that drives the motor coil.

  In this configuration, since two or more drive systems are ensured even during fail-safe, safety can be improved.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, in the said 1st Embodiment, the case where the steering motor was one was shown, and in the said 2nd Embodiment, the case where there were two steering motors was shown. However, the number of steered motors is not limited to this, and any configuration that includes at least one steering motor may be used.

  Moreover, in the said embodiment, the drive force of the steering motors 31 and 36 was demonstrated to the pinion shafts 12 and 16 via the deceleration mechanisms 32 and 38. Alternatively, a configuration (belt drive system) in which the driving force of the steering motor is applied to the rack shaft 5 via a speed reduction mechanism having a pulley and a belt may be used. It is good also as a structure (direct drive system) given directly to a rack axis without going through a mechanism.

DESCRIPTION OF SYMBOLS 100,200 ... Steering control apparatus, 1 ... Steering wheel, 2 ... Wheel, 3 ... 1st steering shaft, 4 ... 2nd steering shaft, 5 ... Rack axis, 6. ..Clutch (connection switching unit), 12 ... pinion shaft, 13 ... torsion bar, 16 ... second pinion shaft, 21 ... steer angle sensor, 22 ... torque sensor, 31 ... -Steering motor, 35 ... Steering controller, 36 ... Second steering motor, 37 ... Second steering controller, 41 ... Reaction force motor, 45 ... Reaction force controller

Claims (5)

A first steering shaft that rotates in accordance with a steering operation by a driver;
A second steering shaft coupled to a rack shaft for steering the wheels;
A connection switching unit that switches connection and disconnection between the first steering shaft and the second steering shaft;
In a state where the connection switching unit is disconnected, a steering motor that applies a steering force to the rack shaft,
A reaction force motor for applying a steering reaction force to the first steering shaft in a state where the connection switching portion is disconnected,
The steering control device according to claim 1, wherein the reaction force motor can apply an assist force to assist a steering operation by a driver to the first steering shaft in a state where the connection switching unit is connected.   When an abnormality occurs in the steering motor or a system that controls the steering motor, the connection switching unit is connected, and the reaction force motor has an assist force that assists a steering operation by a driver. The steering control device according to claim 1, wherein the steering control device is applied to one steering shaft. A torque sensor for detecting a steering torque input by a steering operation by the driver;
When an abnormality occurs in the steering motor or a system that controls the steering motor, the connection switching unit is connected, and the reaction force motor is driven by a driver based on a detection result of the torque sensor. The steering control device according to claim 2, wherein an assist force for assisting a steering operation is applied to the first steering shaft.   The steering control device according to any one of claims 1 to 3, wherein the number of the steering motor is only one.   The steering control device according to any one of claims 1 to 4, wherein the steering motor includes a plurality of systems including a motor coil and a controller that drives the motor coil.

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