JP4404256B2 - Vehicle travel control device - Google Patents

Description

  The present invention relates to a traveling control technique for a vehicle including a power steering device.

  2. Description of the Related Art Conventionally, there is a steer-by-wire type power steering device in which a steering handle and a steered wheel are not mechanically linked as one of devices that control a forklift that is a cargo handling vehicle. Such a power steering apparatus detects, for example, an operation angle of a steering wheel as an electric signal, and drives a steering motor based on the electric signal so that the steering angle of the steering wheel corresponds to the operation angle. Is configured to steer.

  In a vehicle equipped with a steer-by-wire power steering device, the steering handle and the steered wheels are not mechanically connected, so that a situation occurs in which the operation angle of the steering handle does not match the steered angle of the steered wheels. For example, when the steered wheel is caught in a groove or the like, even if the steering handle is operated, the steered wheel is maintained at a constant steering angle regardless of the operation angle of the steering handle. When the steered wheel suddenly escapes from the groove under such circumstances, there is a problem that the steered wheel suddenly turns to an angle corresponding to the operation angle of the steering handle, and the behavior of the vehicle becomes unstable. Moreover, since the vehicle starts to move in a direction unrelated to the operation angle of the steering wheel, there is a problem that the driver cannot drive the vehicle as expected.

  As a countermeasure against this, Patent Document 1 described later discloses a technique for stopping the steering motor when the difference between the steering wheel operating angle and the steering wheel steering angle exceeds a predetermined value, and decelerating or stopping the traveling motor. Technology is disclosed. Patent Document 2 discloses a technique for suppressing an accelerator command value when the steering handle is turning more than a predetermined angle from a straight traveling position at the time of starting in order to increase safety when the vehicle starts in an unintended direction. Has been. Patent Document 3 describes a technique for stopping the start of a vehicle when a target rudder angle and an actual rudder angle are deviated.

JP 2001-30935 A JP 2003-171095 A JP 2003-34262 A

  In a steer-by-wire power steering system, if the steering angle of the steering wheel is controlled to follow the steering wheel operating angle, a steering tracking delay may occur when the driver suddenly operates the steering wheel. It is done. When the steering tracking delay occurs, the vehicle travels in a state where the steered wheels are directed in a direction different from the direction instructed by the steering wheel. Therefore, the vehicle cannot be turned as intended by the driver. There is a problem that the operation is uncomfortable.

  Also, for example, when the steered wheel gets stuck in a groove, it is known that the steering wheel operating angle and the steered wheel steering angle do not match, and the vehicle is driven to escape the steered wheel from the groove. It is also necessary to simply stop the steering motor or stop the traveling motor when the difference between the steering wheel operating angle and the steering wheel steering angle exceeds a predetermined value. There are also situations that cannot be met. Of course, if the motor is suddenly stopped or decelerated, there is a risk of warping.

  The present invention has been proposed based on such circumstances, and it is an object of the present invention to prevent the driver from feeling uncomfortable with respect to the steering operation while ensuring the safety of traveling. .

To achieve the above object, the present invention provides a vehicle travel control device including a power steering device that performs steering by electrically interlocking a steering handle and a steered wheel, and a travel drive device that travels and drives a drive wheel. The steering angle detecting means for detecting the steering angle of the steering wheel, the steering angle detecting means for detecting the steering angle of the steering wheel, and the difference in angle between the steering wheel operating angle and the steering wheel steering angle. Determining means for determining whether or not the angle is equal to or greater than a predetermined angle; and when the angle difference is determined to be equal to or greater than the predetermined angle, the driving of the travel drive device is stopped, and the angle difference is equal to the predetermined angle. provided with a drive control means for releasing the travel drive stops when it is determined that less than, comprising a releasing operation means to be operated for releasing the traveling drive stop of the travel drive device, Serial drive control means, when the releasing operation means is operated, and the configuration and cancels the traveling drive stop of the travel drive apparatus regardless of the determination result by the determination unit.

  According to the travel control device having the above-described configuration, when the angle difference between the steering wheel operation angle and the steering wheel steering angle exceeds a predetermined angle, the driving wheel is not driven to travel, and the vehicle travels only by inertia. . For this reason, the traveling speed of the vehicle is moderately reduced without operating the braking device, and the turning radius can be reduced. In addition, when the steered wheel turns and the angle difference between the steering angle and the operation angle becomes smaller and becomes smaller than the predetermined angle, the driving drive of the driving wheel is resumed, so the running speed is not reduced too much and smooth turning is made. It can be carried out.

Furthermore, it comprises release operation means operated to release the travel drive stop of the travel drive device, the drive control means when the release operation means is operated regardless of the determination result by the determination means With the configuration in which the travel drive stop of the travel drive device is released , the driver can arbitrarily release the stop of the travel drive by operating the release operation means. For example, when it is necessary to drive the vehicle in a situation where the steered wheel gets stuck in a groove and the angle difference between the steering angle and the operation angle is equal to or larger than a predetermined angle, the stop of the driving drive is canceled and the vehicle is not inconvenient. Can be run.

Further, in place of the release operation means includes timer means prior SL angular difference counts the at which time the predetermined angle or more, the drive control means, when the time by the time counting means reaches a predetermined time The travel drive stop of the travel drive device is canceled regardless of the determination result by the determination means, so that the stop of the travel drive can be automatically canceled, the steering angle and the operation angle When it is necessary to drive and drive the vehicle in a situation where the angle difference is greater than or equal to a predetermined angle, the vehicle can be driven without inconvenience. Further, a predetermined time is required until the stop of the traveling drive is released, and the driver can prepare for the resumption of the traveling drive during that time.

  In addition, in the said structure, when the said angle difference is more than the said predetermined angle, it is preferable to provide the alerting | reporting means which alert | reports an alarm. As a result, the driver can easily recognize whether or not the traveling drive is stopped. Therefore, it is necessary to operate the steering handle to make the operation angle and the steering angle smaller than a predetermined angle, or the traveling It can be determined whether or not it is necessary to cancel the drive stop.

  In the present invention, when the difference between the rudder angle and the operation angle is equal to or greater than a predetermined angle, the traveling drive is stopped and the vehicle travels inertially, so the traveling speed of the vehicle is moderately reduced and the turning radius is reduced. can do. Further, after the traveling drive is stopped, when the steered wheel turns and the difference between the steering angle and the operation angle becomes small, the traveling drive of the drive wheel is resumed, so that a smooth turn can be performed. Furthermore, since the stop of the traveling drive can be released, the vehicle can travel without inconvenience when it is necessary to drive the vehicle in a situation where the angle difference between the steering angle and the operation angle is equal to or larger than a predetermined angle. be able to.

  Hereinafter, embodiments in which the present invention is applied to a walkie-type forklift will be described in detail with reference to the drawings. In this specification, the direction on the machine frame 2 side is expressed as the front, and the direction on the fork 3 side is expressed as the rear when the walker type forklift 1 is viewed from the side.

  As shown in FIG. 1, a wake-type forklift 1 is supported by a battery case 4 that houses a battery behind a machine frame 2 so that the battery case 4 can be moved up and down, and a fork 3 is fixed to the bottom of the battery case 4. The battery case 4 and the fork 3 are moved up and down by a lift cylinder 5 supported by the machine casing 2. Further, the machine frame 2 supports a travel motor 7 as a travel drive device via a motor base 6, and is steered via a gear housing 8 that is supported by the motor base 6 so as to be rotatable about a longitudinal axis. A front wheel 9 used both as a wheel and a drive wheel is supported so as to be rotatable around a horizontal axis. A steering motor 10 is supported on the motor base 6, and the front wheel 9 is steered by rotating the gear housing 8 and the front wheel 9 about the longitudinal axis by the steering motor 10. The front wheels 9 are driven to travel by a travel motor 7 and are braked by an electromagnetic brake 11 disposed on the upper side of the travel motor 7. The upper part of the machine casing 2 is covered with a cover 12. In the figure, reference numeral 13 denotes a rear wheel provided below the fork 3.

  A steering handle 20 is provided at the upper end of the cover 12. The steering handle 20 includes a handle column 21 provided to be rotatable around a vertical axis, and a handle bar 22 having a base end supported on an upper portion of the handle column 21 so as to be swingable up and down. A handle 23 is provided at the distal end of 22. Further, the handle bar 22 is provided with an accelerator 24, an alarm lamp 33 and a release switch 34 which will be described later.

  A potentiometer 31 as an operation angle detection means driven by the handle column 21 is provided at the attachment portion of the steering handle 20 of the cover 12. When the handle column 21 is rotated around the vertical axis together with the handle bar 22, The potentiometer 31 detects the operating angle of the steering handle 20. Further, the motor base 6 is provided with a potentiometer 32 as a steering angle detection means driven by the gear of the gear housing 8, and the actual steering angle of the front wheel 9 is detected by the potentiometer 32. The steering motor 10 is driven and controlled by the steering control device 40 so that the actual steering angle coincides with the target steering angle corresponding to the operation angle of the steering handle 20 detected by the potentiometer 31. In the cover 12, in addition to the steering control device 40, a travel control device 50 that includes a determination unit 51 and a drive control unit 52 and controls the travel motor 7 is provided.

  Next, the traveling control process of this embodiment will be described with reference to FIGS.

  When the operation angle of the steering handle 20 detected by the potentiometer 31 and the rudder angle detected by the potentiometer 32 are input to the determination means 51 while the walker type forklift 1 is traveling, the determination means 51 determines the operation angle and the steering angle. An angle difference is calculated, and it is determined whether or not the angle difference is equal to or greater than a predetermined angle (allowable value) set in advance (S1). Here, when the angle difference is greater than or equal to the allowable value, the determination unit 51 notifies the drive control unit 52 of this fact, and the drive control unit 52 indicates that the angle difference between the operation angle and the steering angle is greater than or equal to the allowable value. Is turned on (S2), and the drive control means 52 is instructed to stop driving. The drive control means 52 stops the travel drive of the travel motor 7 by, for example, stopping or interrupting the current supplied to the travel motor 7 (S3).

  In a state where there is an angle difference between the operation angle and the steering angle, the steering motor 10 is drive-controlled and the front wheels 9 are steered, and the angle difference becomes small. However, if the angle difference is greater than or equal to an allowable value, the drive control means 52 continues the driving stop of the traveling motor 7 (S4: Yes → S7: No). When the front wheel 9 is further steered and the angle difference becomes smaller than the allowable value, the determination unit 51 notifies the drive control unit 52 of this, and the drive control unit 52 releases the travel drive stop of the travel motor 7 and the accelerator 24. The travel drive control of the travel motor 7 according to the operation amount is restarted, and the alarm lamp 33 is turned off (S4: No → S5 → S6).

  As described above, when the angle difference between the operation angle of the steering wheel 20 and the steering angle of the front wheel 9 exceeds an allowable value, that is, when a tracking delay occurs in the steering, the front wheel 9 is not driven to travel. The walk-type forklift 1 travels by inertia and turns while slowly decelerating. Further, when the follow-up delay is eliminated and the angle difference between the steering angle and the operation angle becomes smaller than the allowable value, the traveling drive of the front wheels 9 is resumed, so that the vehicle can smoothly turn. In addition, the driver can easily confirm whether or not the traveling motor 7 can be driven by checking whether or not the alarm lamp 33 is in the lit state. By operating the angle difference to be smaller than the allowable value, the stop of the travel drive by the drive control means 52 is released, and the travel drive of the travel motor 7 can be made possible.

  When the driver operates the release switch 34 in a state where the drive control unit 52 stops the travel drive of the travel motor 7, the drive control unit 52 assumes that an operation for canceling the travel drive stop has been performed, and an alarm lamp 33. Is turned off and the travel drive stop is canceled (S7: Yes → S5 → S6). For this reason, even when it is necessary to travel and drive the walker type forklift 1 in a situation where the angle difference between the steering angle and the operation angle is greater than or equal to the allowable value, the walker type forklift 1 can be driven without any inconvenience. In addition, when the angle difference between the operation angle and the steering angle is smaller than the allowable value, the travel drive of the travel motor 7 is not stopped (S1: No).

  In the above description, the case where the walkie-type forklift 1 is running has been described, but the same processing is performed even when the walkie-type forklift 1 is stopped. That is, when the driver activates the walker type forklift 1, the operation angle and the steering angle are input to the determination means 51, and the angle difference is calculated. At this time, if the angle difference is equal to or larger than the allowable value, the traveling drive of the traveling motor 7 is stopped, and the start of the walker type forklift 1 is suppressed. In this state, when the front wheel 9 is steered by the steering motor 10 and the angle difference becomes smaller than the allowable value, the traveling motor 7 can be driven. That is, when the angle difference between the operation angle and the rudder angle is greater than or equal to the allowable value, the walker type forklift 1 does not start, so that the wake type forklift 1 can be prevented from starting in an unintended direction.

  In the above embodiment, the driver can release the travel drive stop by operating the release switch 34. However, for example, the time during which the above-described angle difference is equal to or greater than the allowable value is continued. It is good also as a structure which time-measures with a timer and cancels the driving stop of the drive control means 52 automatically when this time reaches the predetermined time set beforehand. In this way, as in the above-described embodiment, even when it is necessary to drive the walker type forklift 1 while the angle difference between the rudder angle and the operation angle is greater than or equal to the allowable value, the walker type forklift can be operated without inconvenience. 1 can be run. In addition, since it takes a predetermined time to cancel the stop of the travel drive, the driver can prepare for the restart of the travel drive during that time, and safety can be ensured.

It is a side view of the walk type forklift according to the present invention. It is a side view of the principal part of the walk type forklift concerning the present invention. It is a functional block diagram of the present invention. It is a flowchart of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Walk type forklift 7 Traveling motor 9 Front wheel 10 Steering motor 20 Steering handle 24 Accelerator 31 Potentiometer 32 Potentiometer 33 Warning lamp 34 Release switch 40 Steering control device 50 Traveling control device 51 Judgment means 52 Drive control means

Claims (2)

In a vehicle travel control device including a power steering device that performs steering by electrically interlocking a steering handle and a steered wheel, and a travel drive device that travels and drives a drive wheel,
An operation angle detection means for detecting an operation angle of the steering wheel, a steering angle detection means for detecting a steering angle of the steering wheel, and an angle difference between the operation angle of the steering wheel and the steering angle of the steering wheel is a predetermined value. Determining means for determining whether or not the angle is equal to or greater than an angle; and when the angle difference is determined to be equal to or greater than the predetermined angle, the driving of the travel drive device is stopped, and the angle difference is less than the predetermined angle. Drive control means for releasing the travel drive stop when determined, and a release operation means operated to release the travel drive stop of the travel drive device,
The travel control device for a vehicle , wherein when the release operation unit is operated, the drive control unit cancels the travel drive stop of the travel drive device regardless of a determination result by the determination unit. In a vehicle travel control device including a power steering device that performs steering by electrically interlocking a steering handle and a steered wheel, and a travel drive device that travels and drives a drive wheel,
An operation angle detection means for detecting an operation angle of the steering wheel, a steering angle detection means for detecting a steering angle of the steering wheel, and an angle difference between the operation angle of the steering wheel and the steering angle of the steering wheel is a predetermined value. Determining means for determining whether or not the angle is equal to or greater than an angle; and when the angle difference is determined to be equal to or greater than the predetermined angle, the driving of the travel drive device is stopped, and the angle difference is less than the predetermined angle. Drive control means for releasing the travel drive stop when it is determined, and time measuring means for measuring the time when the angle difference is equal to or greater than the predetermined angle,
The drive control means releases the travel drive stop of the travel drive apparatus regardless of the determination result by the determination means when the time by the time measuring means reaches a predetermined time. .

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