JP2012076651A - Vehicle steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle steering device which is excellent in energy-saving and improves durability.SOLUTION: When non-energy-saving steering, such as stationary steering or steering/loading concurrent operation, is performed, a warning light as a recognition means is turned on (step S5) to notify a driver about non-energy-saving steering. A gain k2 of a steering angle speed proportional component of a target steering reaction force Th* is doubled (Step S6) to correct and increase the target steering reaction force Th*. An increase in steering reaction force surely notifies the driver about the non-energy-saving steering. A reaction force control unit functions as a recognition means for notifying the driver about the non-energy-saving steering.

Description

  The present invention relates to a vehicle steering apparatus for a cargo handling vehicle.

In an electric vehicle, in order to warn of a decrease in the remaining amount of battery power for traveling, an electric vehicle has been proposed in which the steering assist force is corrected to the decreasing side when the remaining amount decreases (see, for example, Patent Document 1). ).
In addition, in a battery-type forklift that divides hydraulic oil from a hydraulic pump driven by an electric motor and supplies the hydraulic oil to a cargo handling control device and a hydraulic power steering device, respectively, when the cargo handling device is switched to a non-operation state, There has been proposed a hydraulic control device that prevents the kickback to the steering wheel from occurring by gradually reducing the rotational speed of the electric motor (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 6-191418 (FIGS. 2, 6 and 14th to 15th paragraphs of the specification) JP 2006-347536 A

  On the other hand, in the system in which hydraulic oil from the hydraulic pump driven by the engine is divided and supplied to the cargo handling control device and the hydraulic power steering device, when the cargo handling operation and steering are performed simultaneously, the pressure of the hydraulic pump decreases. . For this reason, the driver has to depress the accelerator pedal to increase the engine speed. Therefore, the fuel consumption has deteriorated.

Also, as in Patent Document 2, even in a system in which a hydraulic pump is driven by an electric motor, a system that is driven by an engine in order to prevent a decrease in applied voltage to the electric motor when cargo handling work and steering are performed simultaneously. As in the case of, it was necessary to increase the engine speed. For this reason, fuel consumption has deteriorated.
Further, in the case of a battery-type forklift, there is a problem that a large current is drawn from the battery at the same time when cargo handling and steering are performed simultaneously, and as a result, the battery voltage decreases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle steering apparatus that is excellent in energy saving and can improve durability.

  To achieve the above object, the present invention steers the steered wheels (6) in the vehicle steering device (1) in which the mechanical connection between the steering member (10) and the steered mechanism (A1) is broken. Steering actuator (12), a reaction force actuator (13) for applying a steering reaction force to the steering member, and a cargo handling actuator (28, 31) for driving the lifting and lowering cargo handling device (3) , Recognition means (39, 72, 73) for allowing the driver to recognize that it is non-energy-saving steering when non-energy-saving steering including at least one of stationary steering and cargo handling simultaneous steering with cargo handling work is performed A vehicle steering apparatus is provided (claim 1).

According to the present invention, when non-energy-saving steering such as stationary steering or cargo handling simultaneous steering is performed, the recognition means causes the driver to recognize that it is non-energy-saving steering. A driver who recognizes that the steering is non-energy-saving steering can improve the driving method, and as a result, wasteful energy consumption can be eliminated. In addition, since the load on the vehicle steering device is reduced, the durability can be improved.
Further, the recognition means may include a warning device (39) that emits sound or light (claim 2). In this case, it is possible to give a warning to the driver who is performing non-energy-saving steering by sound or light so that the driver can be surely aware that the energy-saving steering is being performed.

Further, a reaction force control unit (73) for controlling the reaction force of the reaction force actuator is provided, and the reaction force control unit increases and corrects the target steering reaction force (Th ^* ) when the non-energy-saving steering is performed. Therefore, it may function as the recognition means (claim 3). In this case, when the non-energy-saving steering is performed, the steering reaction force is increased, so that the driver can be surely noticed that the non-energy-saving steering is being performed.

  The target steering reaction force may include a steering angular velocity proportional component (k2, k3, θh ′), and the steering angular velocity proportional component may include a gain (k2) that changes according to the remaining energy (B). (Claim 4). In this case, the gain of the steering angle proportional component of the target steering reaction force is changed according to the remaining amount of energy such as the remaining amount of gasoline or the remaining amount of battery. For example, when the remaining battery level becomes less than a predetermined value, the gain is increased according to the decrease in the remaining battery level. As a result, the driver can be more surely aware that the non-energy-saving steering is being performed, and the driver can be guided to cancel the non-energy-saving steering. As a result, useless energy consumption can be suppressed.

  In addition, a steering control unit (72) that performs steering control of the steering actuator is provided, and the steering control unit recognizes the steering by reducing and correcting a target steering force when the non-energy-saving steering is performed. It may function as a means (claim 5). By reducing the steering force during non-energy-saving steering, the driver can be more surely aware that the vehicle is performing non-energy-saving steering, and wasteful energy consumption can be suppressed.

  Further, the steering control unit includes a current control means (85) for PWM-controlling the power supplied to the steering actuator, and a duty command value (Dr) for PWM control when the non-energy-saving steering is performed. And a duty command value correcting means (84) for correcting the decrease in accordance with the amount (B). In this case, during non-energy-saving steering, the duty command value of PWM control is changed according to the remaining energy. For example, when the remaining battery level becomes less than a predetermined value, the duty command value is decreased according to the decrease in the remaining battery level. As a result, it is possible to limit the steering force, to make the driver more sure that he is performing non-energy-saving steering, and to suppress wasteful energy consumption.

  Further, there may be provided a storage device (71) for storing the history of non-energy-saving steering together with the position information output from the omnidirectional positioning system (GPS) (70). In this case, for example, a place where non-energy-saving steering is frequently occurring can be identified in the factory premises, and at such a corner, for example, at a turning corner, an improvement such as a gentle turning angle or widening of the road width is performed. The driver's consciousness can be improved by reducing unnecessary steering. As a result, energy-saving steering can be promoted, and the load on the vehicle steering apparatus can be reduced by executing energy-saving steering, thereby improving durability. The history of non-energy-saving steering may include a history of energy consumption in addition to the history of stationary steering and simultaneous handling of cargo handling.

  In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

1 is a schematic side view showing a schematic configuration of a forklift as a cargo handling vehicle including a vehicle steering apparatus according to an embodiment of the present invention. It is the schematic for demonstrating the principle of operation which raises / lowers a fork. It is a block diagram which shows the electric constitution of a forklift. It is a block diagram of the reaction force control part of ECU. It is a map figure of battery residual quantity-coefficient k3. It is a flowchart which shows the flow of the main control of ECU. It is a block diagram of the steering control part of ECU of the steering apparatus for vehicles of another embodiment of this invention. FIG. 8 is a map of remaining battery capacity-coefficient k4 in the embodiment of FIG. 8 is a flowchart showing a main control flow of the ECU in the embodiment of FIG. It is a flowchart which shows the flow of the main control of ECU of another embodiment of this invention. It is a flowchart which shows the flow of the main control of ECU of another embodiment of this invention.

A preferred embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic side view showing a schematic configuration of a forklift as a cargo handling vehicle according to an embodiment of the present invention. Referring to FIG. 1, a forklift 1 includes a vehicle body 2, a cargo handling device 3 provided at a front portion of the vehicle body 2, a counterweight 4 provided at a rear portion of the vehicle body 2, and a driving wheel that supports the vehicle body 2. As a front wheel 5 and a rear wheel 6 as a steered wheel, a vehicle drive source 7 including, for example, an engine, a hydraulic pump 8 as a hydraulic source, and a vehicle steering device 9 for steering the rear wheel 6 I have.

The hydraulic pump 8 is driven by an electric motor 61. An electric motor 61 that drives the hydraulic pump 8 and a battery 62 that supplies electric power to a steering actuator 12 and a reaction force actuator 13 described later of the vehicle steering device 9 are mounted on the vehicle body 2.
The vehicle steering device 9 is configured as a so-called steer-by-wire vehicle steering device in which the mechanical connection between the steering member 10 that is a handwheel with a knob and the rear wheel 6 that is a steered wheel is broken. ing. As a steered wheel, a single rear wheel 6 may be provided at the center in the left-right direction of the vehicle body 2, or the rear wheels 6 may be provided on the left and right sides of the vehicle body 2, respectively.

  The vehicle steering device 9 includes the steering member 10 and, for example, an electric motor for turning the rear wheel 6 as a steered wheel in accordance with an operation of the steering member 10, and an ECU 11 (electronic control unit) as control means. A steering actuator 12 that is driven and controlled by the ECU 11, and a reaction force actuator 13 that is driven by the ECU 11. Further, the vehicle steering device 9 includes a steering angle sensor 14 that detects the steering angle of the steering member 10 and a turning angle sensor 15 that detects the turning angle of the rear wheel 6.

The rear wheel 6 as a steered wheel is rotatably supported by a substantially vertical support member 16. The support member 16 is supported through a bearing 17 held by the vehicle body 2 so as to be rotatable about a substantially vertical rotation axis C1.
The rotation of the output shaft of the steering actuator 12 is decelerated via the transmission mechanism 18 and transmitted to the support member 16. The transmission mechanism 18 is provided such that a drive member 19 made of, for example, a drive gear that rotates along with the output shaft of the steering actuator 12, and a support member 16 around the rotation axis C1 so that the support member 16 can rotate along with the drive gear. It has a driven member 20 made of, for example, a driven gear. The transmission mechanism 18 and the turning actuator 12 constitute a turning mechanism A1.

Although not shown, the power of the drive source 7 such as an engine is transmitted to a transmission that performs forward / reverse switching and a shift operation via a torque converter, and further transmitted to left and right front wheels 5 (drive wheels) via a differential. It has become so. The transmission includes a forward clutch and a reverse clutch.
The forklift 1 includes a cab 22 including a driver seat 21. The cab 22 is formed on the vehicle body 2 so as to be surrounded by the frame 23.

  The cargo handling device 3 is lifted and lowered by a pair of left and right outer masts 24 supported by the vehicle body 2 so as to be tiltable about the lower end 24 a, an inner mast 25 supported by the outer mast 24 so as to be lifted and lowered, and the outer mast 24. The lift bracket 26 is supported so as to be supported, and a pair of left and right forks 27 that are attached to the lift bracket 26 and serve as a loading portion for loading a load.

  A tilt cylinder 28 as a cargo handling actuator is interposed between a predetermined portion of the outer mast 24 and a predetermined portion of the vehicle body 2. The tilt cylinder 28 includes a cylinder body 29 having one end that is swingably connected to a predetermined portion of the vehicle body 2, and a rod 30 that protrudes from the other end of the cylinder body 29. The tip of the rod 30 is slidably connected to a predetermined portion of the outer mast 24. As the rod 30 of the tilt cylinder 28 extends and contracts, the outer mast 24 is displaced into an upright posture and a tilted posture.

  Also, a lift cylinder 31 is provided as a cargo handling actuator for moving the inner mast 25 up and down using the outer mast 24 as a guide. The lift cylinder 31 has a cylinder body 32 fixed to the outer mast 24 and a rod 33 protruding from the cylinder body 32. The tip of the rod 33 is fixed to a mounting portion 25 a provided at a predetermined portion of the inner mast 25.

A load sensor 34 as load detecting means for detecting the load of the cargo handling device 3 is attached to the lower part of the cylinder body 32 of the lift cylinder 31. A signal from the load sensor 34 is input to the ECU 11.
In the front part of the cab 22, an operation stand 35 is provided on the bottom surface 22 a of the cab 22, and the driver seat 21 is fixed to the rear part of the cab 22.

  The operation stand 35 includes the operation member 10, a lift operation lever 36 for lifting and lowering the fork 27, and a tilt for swinging the outer mast 24 as a plurality of operation elements for the driver to operate manually. An operation lever 37 and a forward / reverse switching lever 38 are provided. Further, a warning light 39 as a warning device for warning non-energy-saving steering is fixed at a position where the frame 23 on the operation stand 35 is highly visible. The operation stand 35 is provided with various switches not shown.

  In the vicinity of the base of the operation stand 35, an accelerator pedal 40, a brake pedal 41, and a clutch pedal 42 are provided on the bottom surface 22a of the cab 22 as a plurality of operation elements for the driver to operate with his / her feet. Yes. Although the accelerator pedal 40, the brake pedal 41, and the clutch pedal 42 are actually arranged side by side in a direction perpendicular to the paper surface (corresponding to the left-right direction of the vehicle), they are schematically shown in FIG. In FIG. 1, the layout of the lifting / lowering operation lever 36, the tilt operation lever 37, and the forward / reverse switching lever 38 as operation elements is also schematically shown.

  Referring to FIG. 2 that conceptually shows the principle of the operation of raising and lowering the fork 27, a sprocket 43 is rotatably supported on the upper portion of the inner mast 25, and a chain 44 is wound around the sprocket 43. It has been. One end 44 a of the chain 44 is fixed to a fixing portion 24 b provided on the outer mast 24, and the other end 44 b of the chain 44 is fixed to the lift bracket 26. Thereby, the lift bracket 26 and the fork 27 are suspended using the chain 44.

  When the inner mast 25 rises with the extension of the rod 33 of the lift cylinder 31, the sprocket 43 rises with respect to the fixing portion 24 b of the outer mast 24, and the lift bracket 26 and the fork as the loading portion are connected via the chain 44. 27 is raised. The amount by which the fork 27 rises with respect to the ground surface 48 is twice the amount by which the rod 33 of the lift cylinder 31 extends.

A stroke sensor 45 as a loading portion height detecting means for detecting the height of the fork 27 as the loading portion is provided, and a signal from the stroke sensor 45 is input to the ECU 11. A rotary encoder may be used as the stroke sensor 45.
Specifically, a wire 46 having one end locked to the other end 44 b of the chain 44 is wound around a wire drum 47 rotatably supported by the outer mast 24, and the other end of the chain 44 together with the fork 27. When 44b moves up and down, the wire 46 is unwound from the wire drum 47 or unwound. At this time, the ECU 11 detects the number of rotations of the wire drum 47 with a rotary encoder as the stroke sensor 45, calculates the unwinding amount of the wire 46 from the wire drum 47 based on the detected value, and based on the calculated value. Thus, the loading portion height H, which is the height of the fork 27 from the ground surface 48, is detected.

  FIG. 3 is a block diagram showing the main electrical configuration of the forklift 1. Referring to FIG. 3, the ECU 11 includes a steering angle sensor 14 for detecting the steering angle θh of the steering member 10, and a turning angle sensor 15 for detecting the turning angle θw of the rear wheel 6 as a turning wheel. , A vehicle speed sensor 49 for detecting the vehicle speed, a load sensor 34 as a load detecting means for detecting a load W of the fork 27 serving as the loading unit, and a loading unit height which is the height of the fork 27 serving as the loading unit Stroke sensor 45 as a loading portion height detecting means for detecting H, elevating operation lever position sensor 50 for detecting the position of elevating operation lever 36, and tilt operating lever for detecting the position of tilt operating lever 37 As a position sensor 51, a forward / reverse selector switch 52 that operates in response to switching of the forward / reverse switching lever 38, and an energy remaining amount detecting means for detecting the remaining amount of the battery 62 So that the signal from the respective current sensors 54 as a current detecting means for detecting a current flowing through the electric motor 61 for battery residual quantity sensor 53 and the hydraulic pump 8,.

  In addition, the current position information of the vehicle output from the GPS 70 (omnidirectional positioning system) is input to the ECU 11. The GPS 70 has a known configuration including an orientation sensor, a GPS receiver, a map data storage unit and a memory, and a control unit connected thereto. The ECU 11 has a memory 71 as a storage device for storing a history of non-energy-saving steering described later together with position information acquired from the GPS 70 (omnidirectional positioning system).

Further, the ECU 11 has a steering control unit 72 for driving control (steering control) of the steering actuator 12 and a reaction force control unit 73 for driving control (reaction force control) of the reaction force actuator 13. is doing.
Further, the ECU 11 controls the steering actuator 12, the reaction force actuator 13, the lift control valve 55 including an electromagnetic proportional control valve that controls the supply of hydraulic oil from the hydraulic pump 8 to the lift cylinder 31, and the tilt from the hydraulic pump 8. A tilt control valve 56 comprising an electromagnetic proportional control valve for controlling the supply of hydraulic oil to the cylinder 28, and an electromagnetic proportional control valve for controlling the supply of hydraulic oil to the hydraulic cylinder for engaging / disengaging the forward clutch. The forward clutch control valve 57, the reverse clutch control valve 58, which is an electromagnetic proportional control valve for controlling the supply of hydraulic fluid to the hydraulic cylinder for engaging / disengaging the reverse clutch, and the warning lamp 39 are turned on / off. A signal is output to each of the warning light switch 59 and the electric motor 61 for driving the hydraulic pump 8. That.

The ECU 11 performs various controls. For example, the steering control unit 72 of the ECU 11 obtains the target turning angle θw ^* based on the steering angle θh input from the steering angle sensor 14 and the vehicle speed V input from the vehicle speed sensor 49, and from the turning angle sensor 15. The steering actuator 12 is driven and controlled so that the turning angle θw (actual turning angle) detected based on the above signal approaches the target turning angle θw ^* (that is, turning control is performed).

  In addition, the reaction force control unit 73 of the ECU 11 generates the torque for applying the steering reaction force according to the road surface reaction force to the steering member 10 by the reaction force actuator 13 and the steering angle input from the steering angle sensor 14. The reaction force actuator 13 is driven and controlled based on the steering angular velocity θh ′ obtained by differentiating the input steering angle θh (that is, reaction force control is performed).

Further, the ECU 11 sends a control signal to the lifting control valve 55 that controls the supply of hydraulic oil from the hydraulic pump 8 to the lift cylinder 31 according to the position of the lifting operation lever 36 input from the lifting operation lever position sensor 50. Output.
Further, the ECU 11 sends a control signal to the tilt control valve 56 that controls the supply of hydraulic oil from the hydraulic pump 8 to the tilt cylinder 28 according to the position of the tilt operation lever 37 input from the tilt operation lever position sensor 51. Output.

In addition, the ECU 11 outputs a control signal to the forward clutch control valve 57 in response to the forward / reverse switching switch 52 being switched to forward, and the hydraulic pump is operated from the hydraulic pump 8 to operate the forward clutch. Allow oil to be supplied.
Further, the ECU 11 outputs a control signal to the reverse clutch control valve 58 in response to the forward / reverse changeover switch 52 being switched to the reverse direction, and the hydraulic cylinder for operating the reverse clutch is operated from the hydraulic pump 8. Allow oil to be supplied.

As shown in FIG. 4, the reaction force control unit 73 included in the ECU 11 includes a target steering reaction force calculation unit 74 that calculates a target steering reaction force Th ^* , and a target steering reaction force acquired from the target steering reaction force calculation unit 74. A target steering reaction force correction unit 75 that corrects Th ^* when predetermined (when non-energy-saving steering is performed), and a reaction force actuator based on the target steering reaction force Th ^* acquired from the target steering reaction force correction unit 75 13 includes a current control unit 76 that performs PWM (Pulse Width Modulation) control on the power supplied to the power supply 13, and a k3 calculation unit 77 that calculates the coefficient k3 based on the battery remaining amount B input from the battery remaining amount sensor 53. .

Further, the ECU 11 includes a steering angular velocity calculation unit 78 that calculates the steering angular velocity θh by differentiating the steering angle θh input from the steering angle sensor 14, a stationary steering determination unit 79, and a cargo handling simultaneous steering determination unit 80. Yes.
The target steering reaction force calculation unit 74 calculates the target steering reaction force Th ^* using the following equation (1), where k1, k2, and k3 are constants.

Th ^* = k1 · θh + k2 · k3 · θh '(1)
The front term k1 · θh on the right side is a steering angle proportional component, and the rear term k2, k3 · θh 'on the right side is a steering angular velocity proportional component.
Of the gains k2 and k3 of the steering angular velocity proportional component, k2 is a gain used to increase and correct the steering angular velocity proportional component during non-energy-saving steering (stationary steering and simultaneous cargo handling steering).

Of the gains k2 and k3 of the steering angular velocity proportional component, k3 is a gain used to correct the steering angular velocity proportional component according to the remaining battery charge B. In other words, gain k3 is target steering reaction force Th ^* energy of (more specifically, the target steering reaction force Th ^* of the steering angular velocity proportional component k2 · k3 · θh ') increasing rate increasing when the non-energy-saving steering It is a gain for changing according to the battery remaining amount B as a remaining amount.

  The gain k3 is obtained using the battery remaining amount-k3 map shown in FIG. The gain k3 is set to 1 in the region where the steering is barely possible and the remaining battery charge B is less than 10%. In the region where the remaining battery charge B is 10% or more and less than 20%, the gain k3 is set to 1.5, for example. In the region where the battery remaining amount B is 20% or more and less than 50%, the gain k3 increases proportionally from 1 to, for example, 1.5 as the battery remaining amount B decreases. The gain k3 is set to 1 in the region where the remaining battery charge B is 50% or more.

The stationary determination unit 79 determines whether stationary steering is performed based on the vehicle speed V input from the vehicle speed sensor 49 and the steering angular velocity θh ^* input from the steering angular velocity calculation unit 78. Specifically, stationary steering is performed when the vehicle speed V is equal to or less than a predetermined value V1 (V ≦ V1) and the steering angular velocity θh ′ is equal to or greater than a predetermined value θh1 ′ (θh ′ ≧ θh1 ′). Is determined. The stationary determination unit 79 outputs a correction command signal to the target steering reaction force correcting unit 75 when determining that the stationary steering is performed.

  The simultaneous loading / unloading steering determination unit 80 performs the loading operation based on the current i input from the current sensor 54 that detects the current flowing in the electric motor 61 for the hydraulic pump 8 and the steering angular velocity θh ′ input from the steering angular velocity calculation unit 78. It is determined whether or not the cargo handling simultaneous steering is being performed at the same time. When it is determined that the cargo handling simultaneous steering is performed, a correction command signal is output to the target steering reaction force correction unit 75.

  When the cargo handling operation is being performed, in order to supply hydraulic pressure to the lift cylinder 31 and the tilt cylinder 28 as the cargo handling actuator, the current i flowing through the electric motor 61 of the hydraulic pump 8 is greater than or equal to a predetermined value i1 (i ≧ i1). By detecting this, it is detected that cargo handling work is being performed. On the other hand, during steering, since the steering angular velocity θh ′ is equal to or greater than a predetermined value θh1 ′ (θh ′ ≧ θh1 ′), this is detected to detect that steering is being performed.

When the target steering reaction force correction unit 75 receives a correction command signal from the stationary determination determination unit 79 or the cargo handling simultaneous steering determination unit 80, the coefficient k2 of the steering angular velocity proportional component of the above equation (1) is, for example, 2 · k2. By replacing, the target steering reaction force Th ^* is increased and corrected based on the above equation (1).
FIG. 6 is a flowchart showing the main operation of the ECU 11. Referring to FIG. 6, ECU 11 reads the signal from each sensor in step S <b> 1, and then, in step S <b> 2, sets each gain k <b ^{> 1} , k <b ^> 2, k <b ^{> 3} as a fixed constant, Set based on 1). The gain k3 is set to 1 regardless of the remaining battery charge B (k3 = 1).

Next, in step S3, it is monitored whether or not stationary steering is performed, and in step S4, whether or not simultaneous cargo handling steering is performed is monitored.
Specifically, in step S3, the detected vehicle speed V is equal to or less than a predetermined value V1 (V ≦ V1), and the steering angular velocity θh ′ obtained by differentiating the detected steering angle θh is a predetermined value θh 1. If it is above, it is determined that stationary steering is being performed.

In step S4, the current i acquired from the current sensor 54 (the current flowing through the electric motor 61 that drives the hydraulic pump 8) is equal to or greater than a predetermined value i1 (i ≧ i1) (that is, a cargo handling operation is performed). And when the steering angular velocity θh ^* obtained by differentiating the steering angle θh acquired from the steering angle sensor 14 is not zero (that is, steering is being performed), It is determined that steering is being performed.

If it is determined in step S3 that it is not stationary steering (NO in step S3), and if it is determined in step S4 that it is not simultaneous loading / unloading steering (NO in step S4). Then, the process jumps from step S5 to step S8 and proceeds to step S9, where the reaction force control of the reaction force actuator 13 is executed based on the target steering reaction force Th ^* . That is, a normal steering reaction force is used.

  On the other hand, if it is determined in step S3 that it is stationary steering (YES in step S3), the process proceeds to step S5. Further, when it is determined in step S3 that it is not stationary steering (in the case of NO in step S3), and it is determined in step S4 that it is simultaneous handling of cargo handling (in the case of YES in step S4). The process proceeds to step S5.

In step S5, an ON signal is output to the warning light switch 59, the warning light 39 is turned on, and a warning to the effect that the non-energy-saving steering is given to the driver.
Next, in step S6, the gain k2 is increased and corrected by replacing the gain k2 of the steering angular velocity proportional component k2 · k3 · θh ′ of the target steering reaction force Th ^* with, for example, 2 · k2.

Then, in step S7, based on the battery remaining amount B obtained from the remaining battery level sensor 53, with the remaining battery capacity -k3 map of FIG 5, the target steering reaction force Th ^* of the steering angular velocity proportional component k2 · k3 · A gain k3 of θh ′ is set. The gain k3 is a coefficient for adjusting the increase rate when the gain k2 is increased and corrected according to the remaining battery charge B. The gain k3 is corrected to increase from 1 to a maximum of 1.5, for example, when the remaining battery charge B is in the range of 10% or more and less than 50%.

Next, in step S8, the target steering reaction force Th ^* is calculated based on the equation (1) using the gain k2 that has been corrected for increase and the gain k3 for adjusting the increase rate of the gain k2 according to the remaining battery charge B. Increase the correction.
Next, in step S9, the memory 71 indicates that non-energy-saving steering (stationary steering or cargo handling simultaneous steering) has been performed, together with position information acquired from the omnidirectional positioning system (GPS) when the non-energy-saving steering is performed. To remember. Then, it progresses to step S10.

In step S10, the reaction force actuator 13 is driven and controlled (steering control) based on the target turning reaction force Th ^* . That is, when non-energy-saving steering is being performed, the reaction force generated by the reaction force actuator 13 increases.
According to the present embodiment, when non-energy-saving steering such as stationary steering or simultaneous cargo handling steering is performed, the warning light 39 as a recognition means is turned on to allow the driver to recognize that it is non-energy-saving steering. A driver who recognizes that the steering is non-energy-saving steering can improve the driving method, and as a result, wasteful energy consumption can be eliminated. Moreover, since the load concerning the vehicle steering device 9 is reduced, durability can be improved.

In particular, when non-energy-saving steering is performed, the target steering reaction force Th ^* is increased and corrected, thereby increasing the steering reaction force, so that the driver can be surely aware that the vehicle is performing non-energy-saving steering. . That is, the reaction force control unit 73 functions as a recognition unit that makes the driver recognize non-energy-saving steering.
Further, the increase rate of the target steering reaction force Th ^* during non-energy-saving steering is changed according to the remaining battery charge B. Specifically, when the battery remaining amount B is in the range of 20 to 50%, the steering angular velocity proportional component of the target steering reaction force Th ^* is proportionally increased as the battery remaining amount B decreases. As a result, the steering reaction force increases according to the degree of consumption of the battery 62, so that the driver can be guided to cancel the non-energy-saving steering. As a result, useless energy consumption can be suppressed, and consumption of the battery 62 can be suppressed.

As a warning device, a warning device using a warning buzzer or other sound (including sound) may be used instead of the warning light 39. By giving a warning by sound or light to the driver who is performing non-energy-saving steering, the driver can be surely aware that the energy-saving steering is being performed.
Further, since the history of non-energy-saving steering is stored in the memory 71 together with the position information output from the GPS 70 that is an omnidirectional positioning system, for example, a place where non-energy-saving steering frequently occurs can be specified in the factory premises. For example, it is possible to improve the driver's consciousness, for example, by making the turning angle gentler or widening the road at a turning angle, or by reducing unnecessary steering. As a result, energy-saving steering can be promoted, and the load on the vehicle steering device 9 can be reduced by executing energy-saving steering, thereby improving durability.

The history of non-energy-saving steering may include a history of energy consumption (gasoline consumption and battery current consumption) in addition to the history of stationary steering and cargo handling simultaneous steering. For example, by creating an energy consumption map in the factory premises, etc., there is an effect of improving the consciousness of ensuring that the driver performs non-energy-saving steering in a place where the energy consumption is large.
In the embodiment of FIG. 4, the target steering reaction force Th ^* is corrected to be increased during non-energy-saving steering, but instead of this or in combination with this, as in another embodiment shown in FIG. In addition, the steering force may be corrected to decrease. Referring to FIG. 7, the turning control unit 72 included in the ECU 11 includes a target turning angle calculation unit 81 that calculates a target turning angle θw ^* , and a target turning angle acquired from the target turning angle calculation unit 81. a duty command value setting unit 82 for setting a duty command value (duty ratio) of a PWM signal for driving the steering actuator 12 based on θw ^* and the deviation of the steering angle θw acquired from the steering angle sensor 15.

  Further, the steering control unit 72 sets the duty limit coefficient k4 based on the battery remaining amount B acquired from the battery remaining amount sensor 53 using the battery remaining amount-duty limit value map shown in FIG. The duty command value acquired from the duty command value setting unit 82 is multiplied by the duty limit coefficient k4 acquired from the duty limit coefficient setting unit 83 in a predetermined case (when non-energy-saving steering is performed). Thus, a duty command value correction unit 84 that corrects the duty command value, and a current control unit 85 that PWM-controls the power supplied to the steering actuator 12 based on the duty command value acquired from the duty command value correction unit 84. Have.

In the constituent elements of FIG. 7, the same constituent elements as those of FIG. 4 are denoted by the same reference numerals as those of the constituent elements of FIG.
As shown in FIG. 8, the duty limit coefficient k4 is set to 1 in the region where the remaining battery capacity is 50% or more. In the region where the remaining battery capacity is 20% or more and less than 50%, the duty limit coefficient k4 is proportionally decreased from 1 to 0.5, for example, as the remaining battery capacity B decreases. In an area where the remaining battery charge B is less than 20%, the duty limit coefficient k4 is set to 0.5.

FIG. 9 is a flowchart showing the main operation of the ECU 11 in the embodiment of FIG. Referring to FIG. 8, ECU 11 reads the signal from each sensor in step P <b ^{> 1,} and then in step P <b ^{> 2} , target turning angle θw ^* and turning angle sensor acquired from target turning angle calculation unit 81. On the basis of the deviation of the turning angle θw acquired from 15, the duty command value Dr of the PWM signal is calculated.

Next, in step P3, it is monitored whether or not stationary steering is performed, and in step P4, whether or not simultaneous cargo handling steering is performed is monitored.
Specifically, in step P3, the detected vehicle speed V is equal to or less than a predetermined value V1 (V ≦ V1), and the steering angular velocity θh ′ obtained by differentiating the detected steering angle θh is a predetermined value θh 1. If it is above, it is determined that stationary steering is being performed.

In Step P4, the current i acquired from the current sensor 54 (current flowing through the electric motor 61 that drives the hydraulic pump 8) is equal to or greater than a predetermined value i1 (i ≧ i1) (that is, cargo handling work is performed). And when the steering angular velocity θh ^* obtained by differentiating the steering angle θh acquired from the steering angle sensor 14 is not zero (that is, steering is being performed), It is determined that steering is being performed.

  If it is determined in step P3 that it is not stationary steering (NO in step S3), and if it is determined in step P4 that it is not simultaneous cargo handling steering (NO in step P4), Then, the process jumps from Step P5 to Step P8 and proceeds to Step P9, and the turning control of the turning actuator 12 is executed based on the set duty command value Dr. That is, a normal turning force is used.

  On the other hand, if it is determined in step P3 that the steering is stationary (YES in step P3), the process proceeds to step P5. Further, when it is determined in step P3 that it is not stationary steering (in the case of NO in step P3), and it is determined in step P4 that it is simultaneous steering with cargo handling (in the case of YES in step P4). The process proceeds to Step P5.

In Step P5, an ON signal is output to the warning light switch 59, the warning light 39 is turned on, and a warning to the effect that the non-energy-saving steering is given to the driver.
Next, in step P6, based on the remaining battery level B acquired from the remaining battery level sensor 53, the duty limit coefficient k4 is set using the remaining battery level-duty limit coefficient map shown in FIG. The duty limit coefficient k4 is made smaller than 1 in the range where the remaining battery charge B is less than 50%.

In step P7, the duty command value Dr thus set is multiplied by the duty limit coefficient k4 to reduce and correct the duty command value Dr.
Next, in step P8, the memory 71 indicates that non-energy-saving steering (stationary steering or simultaneous cargo handling steering) has been performed, together with position information acquired from the GPS 70 (omnidirectional positioning system) when the non-energy-saving steering is performed. To remember. Thereafter, the process proceeds to Step P10.

In Step P9, the electric power supplied to the turning actuator 12 is PWM-controlled by the current control unit 85 based on the duty command value Dr, thereby drivingly controlling the turning actuator 12 (steering control). That is, when non-energy-saving steering is performed, the turning force generated by the turning actuator 12 decreases.
According to the present embodiment, when non-energy-saving steering such as stationary steering or simultaneous cargo handling steering is performed, the warning light 39 as a recognition means is turned on to allow the driver to recognize that it is non-energy-saving steering. A driver who recognizes that the steering is non-energy-saving steering can improve the driving method, and as a result, wasteful energy consumption can be eliminated. Moreover, since the load concerning the vehicle steering device 9 is reduced, durability can be improved.

  In particular, when non-energy-saving steering is performed, on the condition that the battery remaining amount B is less than 50%, the duty command value Dr is corrected to decrease, so that the steering force by the steering actuator 12 decreases. The driver can be surely noticed that the vehicle is performing non-energy-saving steering. That is, the steered control unit 72 functions as a recognition means for recognizing that the driver is performing non-energy-saving steering.

  Further, the duty limit coefficient k4 that is multiplied by the duty command value Dr during non-energy-saving steering is changed according to the remaining battery charge B. Specifically, the duty limit coefficient k4 is proportionally decreased as the battery remaining amount B decreases in the range where the battery remaining amount B is 20 to 50%. As a result, the turning force decreases in accordance with the degree of consumption of the battery 62, so that the driver can be guided to cancel the non-energy-saving steering. As a result, useless energy consumption can be suppressed, and consumption of the battery 62 can be suppressed.

  Further, since the history of non-energy-saving steering is stored in the memory 71 together with the position information output from the GPS 70 that is an omnidirectional positioning system, for example, a place where non-energy-saving steering frequently occurs can be specified in the factory premises. For example, it is possible to improve the driver's consciousness, for example, by making the turning angle gentler or widening the road at a turning angle, or by reducing unnecessary steering. As a result, energy-saving steering can be promoted, and the load on the vehicle steering device 9 can be reduced by executing energy-saving steering, thereby improving durability.

The history of non-energy-saving steering may include a history of energy consumption (gasoline consumption and battery current consumption) in addition to the history of stationary steering and cargo handling simultaneous steering. For example, by creating an energy consumption map in the factory premises, etc., there is an effect of improving the consciousness of ensuring that the driver performs non-energy-saving steering in a place where the energy consumption is large.
FIG. 10 shows a modification of the embodiment of FIG. This embodiment is different from the embodiment of FIG. 6 in that steps S61 to S63 are added instead of step S6 of the embodiment of FIG. In step S61, for example, based on the change in the remaining battery charge B as the remaining energy, it is determined whether or not the power consumption of the battery 62 as the energy consumption for the immediately preceding predetermined time (for example, 30 seconds) is greater than or equal to a predetermined value. Is done. The energy consumption may be a gasoline consumption.

In step S61, when the energy consumption is equal to or greater than a predetermined value (YES in step S61), the process proceeds to step S62. In step S62, the gain k2 is increased and corrected by replacing the gain k2 of the steering angular velocity proportional component k2 · k3 · θh ′ of the target steering reaction force Th ^* with, for example, 3 × 3. In step S61, if the energy consumption is less than the predetermined value (NO in step S61), the process proceeds to step S63. In Step S63, the gain k2 is increased and corrected by replacing the gain k2 with, for example, 2 × 2 · 2.

By increasing the rate of increase of the steering reaction force when the energy consumption for the last 30 seconds is equal to or greater than a predetermined value, the driver can be surely recognized that the non-energy-saving steering is performed. In the present embodiment, step S7 can be abolished.
FIG. 11 shows a modification of the embodiment of FIG. This embodiment is different from the embodiment of FIG. 9 in that steps P61 and P62 are added between step P6 and step P7 of the embodiment of FIG. In step P61, for example, based on a change in the remaining battery level B as the remaining energy level, it is determined whether or not the power consumption amount of the battery 62 as the energy consumption amount for the immediately preceding predetermined time (for example, 30 seconds) is equal to or greater than a predetermined value. Is done. The energy consumption may be a gasoline consumption.

In step P61, if the energy consumption is equal to or greater than the predetermined value (YES in step P61), the process proceeds to step P62. In step P62, the duty limit coefficient is decreased and corrected by replacing the duty limit coefficient k4 with, for example, 0.5 × k4, which is ½ times.
In step P61, if the energy consumption is less than the predetermined value (NO in step P61), the process proceeds to step P7.

By increasing the rate of increase of the turning force when the energy consumption for the last 30 seconds is equal to or greater than a predetermined value, the driver can be surely recognized that the non-energy-saving steering is performed.
The present invention is not limited to the above-described embodiments. For example, during non-energy-saving steering, the steering reaction force reduction correction of the embodiments of FIGS. 4 to 10 and the embodiments of FIGS. The steering force increase correction may be used in combination. In addition, various modifications can be made within the scope of the claims of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Forklift (cargo handling vehicle), 2 ... Vehicle body, 3 ... Cargo handling device, 6 ... Rear wheel (steered wheel), 9 ... Vehicle steering device, 10 ... Steering member, 11 ... ECU (control means), 12 ... Steering Actuator, 13 ... Reaction force actuator, 14 ... Steering angle sensor (steering angle detecting means), 15 ... Steering angle sensor (steering angle detecting means), 28 ... Tilt cylinder (loading actuator), 31 ... Lift cylinder (loading actuator) ), 39 ... Warning light (recognition means), 49 ... Vehicle speed sensor, 53 ... Battery remaining amount sensor (energy remaining amount detection means), 54 ... Current sensor, 59 ... Warning light switch, 62 ... Battery, 70 ... GPS ( (Omnidirectional positioning system), 71 ... memory (storage device), 72 ... steering control unit (recognition means), 73 ... reaction force control unit (recognition means), 77 ... k3 calculation unit, 83 ... duty limit Number setting unit, 84 ... Duty command value correction unit (duty command value correction unit), 85 ... Current control unit (current control unit), A1 ... Steering mechanism, B ... Battery remaining amount (energy remaining amount), Dr ... Duty Command value, i ... current, k2 ... gain, k3 ... coefficient, k4 ... duty limit coefficient, θh ... steering angle, θw ... turning angle, θw ^* ... target turning angle, Th ^* ... target steering reaction force, V ... Vehicle speed

Claims (7)

In the vehicle steering apparatus in which the mechanical connection between the steering member and the steering mechanism is broken,
A steering actuator for steering the steered wheels;
A reaction force actuator for applying a steering reaction force to the steering member;
A cargo handling actuator for driving a lifting and lowering cargo handling device;
A non-energy-saving steering including at least one of a stationary steering and a cargo-handling simultaneous steering with a cargo-handling operation, and a recognition means for allowing the driver to recognize that the vehicle is a non-energy-saving steering. A vehicle steering device.   2. The vehicle steering apparatus according to claim 1, wherein the recognition means includes a warning device that emits sound or light. In Claim 1 or 2, comprising a reaction force control unit for controlling the reaction force of the reaction force actuator,
The said reaction force control part is a vehicle steering device which functions as the said recognition means by carrying out the increase correction | amendment of the target steering reaction force when the said non-energy-saving steering is performed. In Claim 3, the target steering reaction force includes a steering angular velocity proportional component,
The steering angular velocity proportional component is a vehicle steering apparatus including a gain that changes in accordance with the remaining energy. In any one of Claims 1-4, The steering control part which carries out steering control of the said steering actuator is provided,
The steering control unit is a vehicle steering device that functions as the recognition unit by reducing and correcting a target steering force when the non-energy-saving steering is performed.   6. The steering control unit according to claim 5, wherein when the non-energy-saving steering is performed, the duty control value of the PWM control is determined according to the remaining amount of energy when the non-energy-saving steering is performed. And a duty command value correcting means for correcting the decrease.   7. The vehicle steering apparatus according to claim 1, further comprising a storage device that stores a history of non-energy-saving steering together with position information output from an omnidirectional positioning system (GPS).

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