JP2019109863A - Drive steering device of unmanned carrier - Google Patents

Abstract

To provide a drive steering device of an unmanned carrier with which it is possible to cause a carriage to travel while being changed from one posture to another.SOLUTION: The drive steering device of an unmanned carrier comprises: a front wheel drive unit attached to a loading platform, for driving a front wheel; a rear wheel drive unit attached to a loading platform 21, for driving a rear wheel; a displacement detector 61 for detecting the position and posture of the loading platform and outputting a travel error Δy between the detected position and an external position command value yand a posture error Δψ between the detected posture and an external posture command value ψ; and a drive steering control unit 62 for generating a front and a rear wheel speed command signal (v, v) and a front and a rear wheel steering angle command signal (Δθ, Δθ) on the basis of the travel error Δy, the posture error Δψ and an external speed command signal (v). The drive steering control unit 62 includes a steering angle control unit 66 for generating a front and a rear wheel steering angle command signal (Δθ, Δθ) so that the travel error Δy and the posture error Δψ are cleared.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a drive steering apparatus for an unmanned transfer vehicle.

  2. Description of the Related Art An unmanned transport vehicle that transports objects such as parts and boxes automatically without using human hands is used in manufacturing factories that manufacture products and warehouses that store and manage products. The unmanned transport vehicle includes a loading platform on which an object to be transferred is placed, and a drive steering device that moves the loading platform along a designated trajectory defined on the floor surface by a magnetic tape, a marker, or the like. The drive steering apparatus comprises at least two omnidirectional drive units provided with drive steered wheels, and a controller for controlling the omnidirectional drive units.

  Patent Document 1 discloses a drive steering method for driving steered wheels of two omnidirectional drive units provided in the lower part of the bed of such an unmanned transfer vehicle. In the drive steering method of Patent Document 1, the front wheel steering angle command for the front drive steering wheel and the speed command for the center point of the platform are acquired as external commands, and the coordinates of the turning center are obtained based on the front wheel steering angle command and the speed command. Position, rear wheel steering angle command, turning radius of center point, turning radius of front drive steering wheel, and turning radius of rear drive steering wheel are calculated, and front and rear omnidirectional drive to realize these commands Control the unit.

JP, 2010-256941, A

  According to the invention of Patent Document 1, the unmanned transfer vehicle is drive-steered so that the front and rear drive steered wheels draw an arc centered on the turning center. However, in the drive steering method of Patent Document 1, since the turning center is determined on the X axis extending along the vehicle width direction from the center point of the loading platform, the movement path of the unmanned transfer vehicle is significantly restricted. Further, in the invention of Patent Document 1, the unmanned transfer vehicle is maintained in a posture in which the main axis (for example, the longitudinal axis of the unmanned transfer vehicle) and the tangent of the designated trajectory are always parallel.

  An object of the present invention is to provide a drive steering apparatus for an unmanned transfer vehicle capable of traveling while changing a platform in various postures.

(1) The drive steering apparatus (for example, drive steering apparatus 3 described later) according to the present invention drives and steers an unmanned transport vehicle (for example, unmanned transport vehicle 1 described later) traveling based on a predetermined external command. And mounted on a platform (for example, a loading platform 21 described later), and in response to a first speed command (v _F ^* ) and a first steering angle command (Δθ _F ^* ), a first drive steering wheel (for example A first drive unit (for example, a front wheel drive unit 4F described later) for driving the front wheel 41F), and the second speed command (v _R ^* ) and a second steering angle command (Δθ _R ^* ) attached to the base portion The second drive unit (for example, a rear wheel drive unit 4R described later for driving the second drive steering wheel (for example, a rear wheel 41R described later) according to Misalignment (Δy) between the sensor and external position command and inspection A displacement detector (for example, a displacement detector 61 described later) that outputs an attitude deviation (Δψ) between the outgoing attitude and the external attitude command, and the positional deviation, the attitude deviation, and the external speed command (v ^* ) And a controller (e.g., a controller 6, 6A described later) that generates the first and second speed commands and the first and second steering angle commands, and the controller is configured to A steering angle control unit (for example, steering angle control units 66 and 66A described later) that generates the first and second steering angle commands so as to eliminate the deviation and the attitude deviation is characterized.

  (2) In this case, the steering angle control unit generates a first control input (α) according to the positional deviation (eg, traveling error feedback controllers 661 and 661A described later), and the attitude The first feedback controller (for example, posture error feedback controllers 662 and 662A described later) that generates a second control input (β) according to the displacement, and the first and second displacement controllers do not interfere with the displacement and the displacement. And a non-interference controller (for example, non-interference controllers 663 and 663A described later) that generate the first and second steering angle commands based on the second control input.

(3) In this case, when both of the first control input and the second control input are 0, the non-interference controller is configured such that both the first steering angle command and the second steering angle command have predetermined reference axes For example, it is preferable to generate the first and second steering angle commands so as to be parallel to the main axis O _AGV and the advancing axis O _Δ ) described later.

(4) In this case, an axis connecting the first steering axis of the first drive steering wheel and the second steering axis of the second drive steering wheel (for example, a mounting axis _OPWS described later) and the main shaft of the base ( For example, it is preferable that the main axis O _AGV described later is inclined at a predetermined mounting angle (φ _AGV ) at the center point of the pedestal, and the reference axis is parallel to the main axis.

(5) In this case, the non-interference controller sets the first control input as α, the second control input as β, an angle between the mounting shaft and the main shaft as φ _AGV, and the first steering shaft Preferably, a distance along the mounting axis between the wheel and the second steering axis is H _AGV, and the first steering angle command Δθ _F ^* and the second steering angle command Δθ _R ^* are generated according to the following equation .

(6) In this case, preferably, the reference axis is parallel to the advancing axis of the platform (for example, the advancing axis O _Δ described later).

(7) In this case, the non-interference controller sets the first control input to α and the second control input to β, and the first steering axis of the first drive steering wheel and the second of the second drive steering wheel 2 An angle formed by a mounting shaft connecting the steering shaft and the main shaft is φ _AGV , a distance along the mounting shaft between the first steering shaft and the second steering shaft is H _AGV , and the advancing shaft Preferably, the first steering angle command Δθ _F ^* and the second steering angle command Δθ _R ^* are generated according to the following equation, where λ is an angle formed by the mounting shaft and the mounting shaft.

(8) In this case, the drive steering device detects a steering angle (Δθ _F ) of the first drive steering wheel and generates a first steering angle detection signal (for example, front wheel steering described later) Angle sensor 47F), and a second steering angle detector (for example, a rear wheel steering angle sensor 47R described later) that detects a steering angle (Δθ _R ) of the second drive steering wheel and generates a second steering angle detection signal And the control device calculates an axial minute movement distance (dl) which is a minute movement distance of the platform along the attachment axis based on the first and second steering angle detection signals. A minute movement distance calculation unit (for example, a minute movement distance calculation unit 64, 64A described later) is provided, and the first and second feedback controllers execute the first and second feedback control rules according to the feedback control law using the axial minute movement distance as a variable. Generate second control input Rukoto is preferable.

(9) In this case, the drive steering device detects a steering angle (Δθ _F ) of the first drive steering wheel and generates a first steering angle detection signal (for example, front wheel steering described later) Angle sensor 47F), and a second steering angle detector (for example, a rear wheel steering angle sensor 47R described later) that detects a steering angle (Δθ _R ) of the second drive steering wheel and generates a second steering angle detection signal , And the control device is a mounting shaft connecting the first steering shaft of the first drive steering wheel and the second steering shaft of the second drive steering wheel (for example, a mounting shaft _OPWS described later). A minute movement distance calculation unit (compute movement distance (dl) in the axial direction, which is a minute movement distance along the mounting axis of the platform, based on the first and second steering angle detection signals. For example, a minute movement distance calculation unit 64, 64A) described later is provided, and the first and Feedback controller preferably generates said first and second control input in accordance with the feedback control law which said axial small moving distance as a variable.

(10) In this case, the control device is configured to move the minute movement distance (dl _F cos _{F F} ) along the attachment axis of the first drive steering wheel and the minute movement distance along the attachment axis of the second drive steering wheel A speed control unit (for example, described later) that generates the first and second speed commands based on the first and second steering angle detection signals and the external speed command so that (dl _F cos _{F F} ) becomes equal. Preferably, the speed control unit 65, 65A) is provided.

  (1) The drive steering apparatus according to the present invention uses three of the external speed command, the external position command, and the external attitude command as the external command, and the first detector based on the external command by the deviation detector and the controller. A first speed command and a first steering angle command for the steered wheels and a second speed command and a second steering angle command for the second drive steered wheels are generated. In particular, the deviation detector detects a positional deviation between the detection position of the platform and the external position command and a posture deviation between the detected attitude of the pedestal and the external attitude command, and the controller detects the misalignment by the deviation detector. First and second steering angle commands for the first and second drive steered wheels are generated so that the detected positional deviation and attitude deviation are eliminated. Thus, it is possible to cause the platform to travel at a speed according to the external speed command along a path according to the external position command, in a posture according to the external posture command. That is, according to the present invention, the specified route can be made to travel at the specified speed while changing the platform in various postures according to the external posture command, so the position of the turning center is limited as in the prior art. It is possible to realize traveling with a higher degree of freedom than in the past.

  (2) If the steering angles of the first and second drive steered wheels are independently changed without setting any restraint condition, both the position and the attitude of the base change. Therefore, in the present invention, the first feedback controller generates a first control input according to the positional deviation, the second feedback controller generates a second control input according to the posture deviation, and the non-interference controller further generates these positional deviations. The first and second steering angle commands are generated based on the first and second control inputs so as not to interfere with the attitude deviation. Thus, according to the present invention, positional deviation and posture deviation can be controlled independently, and travel with a high degree of freedom can be realized smoothly.

  (3) In the non-interference controller of the present invention, when the first and second control inputs are both 0, that is, when there is no positional deviation and posture deviation, both the first and second steering angle commands are on the reference axis. The first and second steering angle commands are generated to be parallel to each other. Thereby, when there is no positional deviation and posture deviation, the directions of the first and second drive steered wheels can be aligned with a predetermined reference axis, and convenience can be improved.

  (4) In the present invention, the first and second drive units are mounted on the base portion such that the mounting shaft of each drive steering wheel and the main shaft of the base portion are inclined at the mounting angle at the central point. Here, the main axis corresponds to, for example, a longitudinal axis when the base portion is rectangular in plan view. When the unmanned transport vehicle travels along a linear route, in many cases, the base portion is controlled so that its main axis and a magnetic tape, a marker or the like specifying the linear route overlap. In the present invention, by tilting the attachment shaft and the main shaft, the automated guided vehicle can be made to travel such that the first and second drive steered wheels do not step on the magnetic tape, the marker or the like provided on the floor surface. Also, by making the main axis parallel to the basic traveling direction of the automatic guided vehicle parallel to the reference axis as described above, the orientations of the first and second drive steered wheels when there is no positional deviation and posture deviation. Can be made parallel to this basic direction of travel, further improving convenience.

(5) The non-interference controller of the present invention generates the first steering angle command Δθ _F ^* and the second steering angle command Δθ _F ^* in accordance with the above equations (1-1) and (1-2). Thereby, positional deviation and attitude deviation can be controlled independently, and when there is no positional deviation and attitude deviation, the directions of the first and second drive steering wheels can be aligned parallel to the basic traveling direction . In addition, the convenience can be further improved.

  (6) In the present invention, by making the advancing axis of the base portion parallel to the reference axis, when there is no positional deviation and posture deviation, the direction of the first and second drive steering wheels is set to the advancing of the base portion Since the alignment can be made parallel to the axis, the convenience can be further improved.

(7) The non-interference controller of the present invention generates the first steering angle command Δθ _F ^* and the second steering angle command Δθ _F ^* according to the above equations (2-1) and (2-2). Thereby, positional deviation and attitude deviation can be controlled independently, and when there is no position deviation and attitude deviation, the directions of the first and second drive steering wheels can be aligned parallel to the advancing axis of the base. Therefore, the convenience can be further improved.

  (8) In the present invention, based on the first and second steering angle detection signals, the axial minute movement distance which is the minute movement distance along the mounting axis is calculated. The first and second feedback controllers generate the first and second control inputs in accordance with a feedback control rule that uses the small axial movement distance as a variable. This allows the response to distance to be constant. In other words, the automatic guided vehicle can travel along a constant route regardless of the speed.

  (9) According to the present invention, the same effect as the above (8) is exerted.

  (10) Since the first and second drive units are attached to the base portion, the distance along the attachment axis between the first drive steering wheel and the second drive steered wheel is always constant. Therefore, the speed control unit of the present invention is configured such that the minute movement distance along the attachment axis of the first drive steering wheel and the minute movement distance along the attachment axis of the second drive steering wheel are equal, in other words, By generating the first and second speed commands such that the component of the velocity vector of the drive steered wheel along the attachment axis and the component of the velocity vector of the second drive steered wheel along the attachment axis are equal. It is possible to prevent the drive steered wheels from idling and the application of excessive force between the drive steered wheels. Therefore, according to the present invention, wasteful consumption of power can be suppressed while realizing traveling with higher freedom than in the case where the position of the turning center is limited as in the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the automatic guided vehicle which concerns on 1st Embodiment of this invention, and its drive steering apparatus. It is a top view of a trolley | bogie and is a figure for demonstrating the definition of the various parameters prescribed | regulated in a control apparatus. It is a figure which shows the structure of the control circuit of a control apparatus. It is a figure for demonstrating the procedure of position / attitude | position gap | deviation detection control. It is a top view of a trolley | bogie and is a figure for demonstrating the specific procedure of drive steering control in a drive steering control part. It is a block diagram of a drive steering control part. It is a figure which shows an example of the control result of the trolley | bogie by a control apparatus. It is a figure which shows the structure of the control apparatus of the drive steering apparatus which concerns on 2nd Embodiment of this invention. It is a top view of a trolley | bogie and is a figure for demonstrating the specific procedure of drive steering control in a drive steering control part.

First Embodiment
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the configuration of an automatic guided vehicle 1 and a drive steering apparatus 3 according to the present embodiment.

  The unmanned transport vehicle 1 is configured by combining a carriage 2 and a drive steering device 3 which is attached to the carriage 2 and travels the carriage 2 along a linear guide line L previously disposed on the floor surface F. Be done.

  The dolly 2 has a rectangular plate-shaped loading section 21, casters 22 provided at four corners of the loading section 21 on the floor F side, and a frame erected at the short side edge section 24RR of the loading section 21. And a handle 23 in the shape of a circle. In the following, for convenience of explanation, the short side edge 24RR side of the loading section 21 provided with the handle 23 is referred to as the rear side of the bogie 2, and the short side edge 24FF not provided with the handle 23 is provided as a bogie It is called the front side of 2. In addition, the definition of the front and back of these trolley | bogies 2 is a thing for convenience of explanation, and the advancing direction of the trolley | bogie 2 is not limited to this direction. Moreover, although the case where a conveyance target object (not shown) is mounted in the loading platform 21 and self-propelled by the unmanned conveyance vehicle 1 alone is described below, the present invention is not limited to this. The unmanned transfer vehicle 1 can also be used as a tow truck for pallets, for example, by connecting a pallet (not shown) on which the object to be transferred is mounted and the carriage 2.

  The drive steering device 3 includes a front wheel drive unit 4F including a front wheel 41F which is a drive steerable wheel capable of both rotational drive and steering, and a rear wheel 41R which is a drive steerable wheel capable of both rotational drive and steering. Wheel drive unit 4R, front sensor 5F and rear sensor 5R for detecting the position and attitude of load carrier 21 relative to floor surface F, battery B for supplying power to drive units 4F and 4R, and each sensor 5F , And 5R, and the control device 6 that controls each of the drive units 4F and 4R.

  The front wheel drive unit 4F is attached to the front side of the floor surface F of the loading section 21, more specifically, on the short side edge 24FF side and near the long side edge 25L. The front wheel drive unit 4F includes a front wheel 41F in contact with the floor F, and a drive unit 42F that drives and steers the front wheel 41F according to a front wheel speed command signal and a front wheel steering angle command signal described later transmitted from the control device 6. . When the front wheel speed command signal and the front wheel steering angle command signal are input, the drive unit 42F rotationally drives the front wheel 41F so that these commands are realized, or the front wheel steering with the front wheel 41F perpendicular to the bed 21 The steering drive is performed centering on the shaft 43F. Hereinafter, the rotational speed of the front wheel 41F is also referred to as the front wheel speed, and the angle of the front wheel 41F around the front wheel steering shaft 43F is also referred to as the front wheel steering angle.

  The front wheel drive unit 4F detects a front wheel speed and detects a front wheel speed sensor 46F (see FIG. 3 described later) that transmits a front wheel speed detection signal corresponding to the detected value to the control device 6, and a front wheel steering angle A front wheel steering angle sensor 47F (see FIG. 3 described later) that transmits a front wheel steering angle detection signal corresponding to the detected value to the control device 6 is provided.

  The rear wheel drive unit 4R is attached at a position behind the front wheel drive unit 4F on the floor F side of the loading section 21, more specifically on the short side edge 24RR side and near the long side edge 25R. Be The rear wheel drive unit 4R drives and steers the rear wheel 41R according to a rear wheel 41R in contact with the floor F and a later-described rear wheel speed command signal and a rear wheel steering angle command signal transmitted from the control device 6 And 42R. When the rear wheel speed command signal and the rear wheel steering angle command signal are input, the drive unit 42R rotationally drives the rear wheel 41R to realize these commands, or the rear wheel 41R with respect to the loading platform 21. The steering drive is performed around the vertical rear wheel steering shaft 43R. Hereinafter, the rotation speed of the rear wheel 41R is also referred to as rear wheel speed, and the angle around the rear wheel steering shaft 43R of the rear wheel 41R is also referred to as rear wheel steering angle.

  The rear wheel drive unit 4R also detects a rear wheel speed and transmits a rear wheel speed detection signal according to the detected value to the control device 6 (see FIG. 3 described later), and a rear wheel steering A rear wheel steering angle sensor 47R (see FIG. 3 described later) that detects an angle and transmits a rear wheel steering angle detection signal according to the detected value to the control device 6 is provided.

The front sensor 5F is attached to the front side of the floor F side of the loading section 21. More specifically, the front sensor 5F is provided on the main axis O _AGV described later in plan view and on the front side of the center point P _AGV (see FIG. 2 described later). For example, a camera that captures an image of the floor surface F is used as the front sensor 5F. The front sensor 5F captures an image including the guiding line L in the floor surface F, and transmits an image signal to the control device 6.

The rear sensor 5 </ b> R is attached to the rear side of the floor surface F of the loading section 21 with respect to the front sensor 5 </ b> F. More specifically, the rear sensor 5R is provided on the main axis O _AGV described later in plan view and on the rear side of the central point P _AGV (see FIG. 2 described later). For example, a camera that captures an image of the floor surface F is used as the rear sensor 5R. The rear sensor 5 </ b> R captures an image including the guiding line L in the floor surface F, and transmits an image signal to the control device 6. The position and posture of the loading platform 21 with respect to the guide line L are specified by calculation in the deviation detector 61 described later based on the image signals obtained by the front sensor 5F and the rear sensor 5R.

  The battery B is attached to, for example, the handle 23 side of the loading unit 21. The control device 6 is attached to, for example, the handle 23 of the carriage 2.

  Next, with reference to the plan view of the carriage 2 of FIG. 2, the definition of various parameters and coordinate systems defined in the control device 6 in order to grasp the position and attitude of the carriage 2 will be described.

As described above, the front wheel steering shaft 43F of the front wheel 41F and the rear wheel steering shaft 43R of the rear wheel 41R are provided diagonally with respect to the bed 21 of the truck 2 in a plan view. Hereinafter, an axis passing through the front wheel steering shaft 43F and the rear wheel steering shaft 43R is referred to as a mounting axis _OPWS . The A on the mounting shaft _{O PWS,} the midpoint between the front wheel steering shaft 43F and the rear wheel steering shaft 43R of the center point _{P AGV} bogie 2. In the following, the distance along the mounting axis _OPWS between the front wheel steering shaft 43F and the rear wheel steering shaft 43R is referred to as front and rear wheel distance H _AGV .

In the following, an axis parallel to the long side edge portions 25L and 25R of the loading section 21 and passing through the center point P _AGV is referred to as a main axis O _{AGV of the} carriage 2. In the following, the angle formed by the mounting axis _OPWS and the spindle _OAGV is referred to as a mounting angle _φAGV .

The front wheel 41F is rotatably provided centering on a front wheel rotation shaft 45F parallel to the loading section 21. Hereinafter, the rotational speed of the front wheel rotating shaft 45F around the front wheel 41F of the front wheel speed _{v F.} The front wheel speed v _F is detected by the front wheel speed sensor 46F which is provided in the front wheel drive unit 4F (see FIG. 3).

Further, the front wheel 41F is rotatably provided centering on a front wheel steering shaft 43F which is perpendicular to the loading section 21. Hereinafter, an angle formed by the traveling direction of the front wheel 41F and the main axis O _AGV is referred to as a front wheel steering angle Δθ _F. The front-wheel steering angle [Delta] [theta] _F is detected by the front-wheel steering angle sensor 47F provided in the front wheel drive unit 4F (see FIG. 3 described later). In the following, angle between the traveling direction and the mounting shaft O _PWS of the front wheels 41F, i.e., angular obtained by subtracting the mounting angle phi _AGV from the front wheel steering angle [Delta] [theta] _F that front-wheel steering angle [rho _F.

The rear wheel 41 </ b> R is provided rotatably about a rear wheel rotation axis 45 </ b> R parallel to the loading section 21 as a central axis. Hereinafter, the rotational speed of around wheel axle 45R of the rear wheel 41R as the rear wheel speed v _R. The rear wheel speed v _R is detected by the after provided to the rear wheel drive unit 4R wheel speed sensor 46R (see FIG. 3).

The rear wheel 41 </ b> R is rotatably provided centering on a rear wheel steering shaft 43 </ b> R perpendicular to the loading section 21. Hereinafter, an angle formed by the traveling direction of the rear wheel 41R and the main axis O _AGV is referred to as a rear wheel steering angle Δθ _R. The rear wheel steering angle Δθ _R is detected by a rear wheel steering angle sensor 47R (see FIG. 3 described later) provided in the rear wheel drive unit 4R. In the following, a rear angle between the traveling direction and the mounting shaft O _PWS ring 41R, i.e. angle obtained by subtracting the mounting angle phi _AGV from the rear wheel steering angle [Delta] [theta] _R be that the rear wheel steering angle [rho _R.

Further, in the control device 6, the position of the center point P _AGV of the carriage 2 is divided into two Cartesian coordinate systems of the spindle coordinate system (see solid line arrow in FIG. 2) and the mounting axis coordinate system (see dashed line arrow in FIG. 2). To grasp.

The main axis coordinate system is a coordinate system in which the X axis and the main axis O _AGV are parallel and the front wheel 41 F side of the main axis O _AGV is the positive side of the X axis. In the following, the position vector of the central point P _AGV in the main axis coordinate system is denoted as P _AGV ^AGV = [x _AGV ^AGV , y _AGV ^AGV ].

The mounting axis coordinate system, is its X-axis and the mounting shaft O _PWS are parallel, and the coordinate system of the front wheel 41F side and the positive side of the X-axis of the mounting shaft O _PWS. In the following, the position vector of the center point P _AGV in the mounting axis coordinate system is expressed as P _AGV ^PWS = [x _AGV ^PWS , y _AGV ^PWS ]. Note that the position vector of the main axis coordinate system and the position vector of the mounting axis coordinate system can be mutually converted by a conversion matrix shown in equation (8-1) described later.

Further, in the control device 6, the posture of the carriage 2 is grasped by a vehicle body angle which is an angle formed by the main axis O _AGV and a predetermined reference axis O _BS . In the present embodiment, the reference axis O _BS is taken as the reference tangent O _L of the induction line L as described later with reference to FIG. 4, but the present invention is not limited to this.

  FIG. 3 is a diagram showing a configuration of a control circuit of the control device 6. As shown in FIG. The control device 6 controls the front wheel drive unit 4F and the rear wheel drive unit 4R so as to eliminate the deviation detected by the deviation detector 61 and the deviation detected by the deviation detector 61. And a control unit 62.

  The shift detector 61 is a position / attitude described below based on the image signals transmitted from the front sensor 5F and the rear sensor 5R provided on the carriage 2, the external position command signal, and the external attitude command signal. By performing the shift detection control, the position error signal and the attitude shift signal are generated and transmitted to the drive steering control unit 62.

FIG. 4 is a plan view of the carriage 2 and is a view for explaining the procedure of position / posture shift detection control in the shift detector 61. As shown in FIG. In FIG. 4, a guiding line L disposed on the floor F, and a central point P _{AGV serving as} a reference for specifying the position of the truck 2 with respect to the floor F of the truck 2 and the floor of the truck 2 The main spindle O _{AGV as} a reference in specifying the attitude with respect to the plane F is illustrated.

First, the shift detector 61 obtains information on the position and the shape of the guiding line L based on the image signals transmitted from the front sensor 5F and the rear sensor 5R. Next, in the deviation detector 61, based on the acquired information, the intersection of the position of the central point P _AGV in the main axis coordinate system and the line passing through the central point P _AGV and perpendicular to the main axis O _AGV and the induction line L and it calculates the position of the reference point P _L is. In the following, it sets the position of the origin of the spindle coordinate system to the reference point P _L. Thus, the position of the center point _{P AGV} bogie 2 is represented by the distance _y ^{AGV AGV} from the reference point _{P L} to the center point _{P AGV.} Hereinafter, the distance between the center point P _AGV and the reference point P _L will be referred to as a detected travel position y _AGV ^{AGV of} the carriage 2. Further, the deviation detector 61 calculates the direction of the reference tangent line _{L L} which is a tangent at the reference point P _L of the induction line L based on the acquired information, and further the angle 成 す formed by the main axis O _AGV and the reference tangent line _{L L} Calculate Hereinafter, an angle formed by the main axis O _AGV and the reference tangent O _L is referred to as a detected vehicle body angle 。.

In the deviation detector 61, an external position command signal corresponding to a position command value y ^* corresponding to a command value for the detected traveling position y _AGV ^AGV by using a wireless communication means not shown, and for the detected vehicle body angle ψ An external attitude command signal corresponding to an attitude command value ψ ^* corresponding to the command value is acquired. Next, deviation detector 61 calculates traveling error Δy (= y ^* −y _AGV ^AGV ) by subtracting detected traveling position y _AGV ^AGV from position command value y ^* , and further detects attitude from attitude command value ψ ^* The attitude error Δψ is calculated by subtracting ψ, and a position error signal according to the traveling error Δy and an attitude deviation signal according to the attitude error Δψ are output to the drive steering control unit 62.

As described above, in the control device 6, by using the external position command signal and the external attitude command signal, the distance between the center point P _AGV of the carriage 2 and the induction line L, and the guidance of the main axis O _AGV of the carriage 2 The angle with respect to the tangent of the line L can be freely specified. That is, when it is desired to cause the carriage 2 to travel so that its center point P _AGV traces directly above the induction line L, the position command value y ^* of the external position command signal may be set to 0. When it is desired to travel so that the main axis O _AGV is always parallel to the tangent of the induction line L, the attitude command value ψ ^* of the external attitude command signal may be set to zero.

Returning to FIG. 3, the drive steering control unit 62 determines the driving speed Δy and the attitude error Δψ detected by the deviation detector 61, the external speed command signal according to the command value v ^* for the speed of the carriage 2, and each drive unit By performing the drive steering control described below based on the steering angles Δθ _F and Δθ _{R of} both wheels detected by the steering angle sensors 47F and 47R provided in 4F and 4R, the running error Δy and the attitude In accordance with the command value v _F ^* for the front wheel speed v _F and the command value v _R ^* for the rear wheel speed v _R so that the error Δψ becomes 0 and the command value v ^* is realized a wheel speed command signal after, the front-wheel steering angle and the front wheel steering angle command signal according to the command value [Delta] [theta] _F ^* for [Delta] [theta] _F, wheel steering angle command signal after corresponding to the command value [Delta] [theta] _R ^* with respect to the rear wheel steering angle [Delta] [theta] _R And generate Inputting a et command signals each drive unit 4F, the 4R.

  Before describing the specific procedure of the drive steering control in the drive steering control unit 62, the equation of motion established for the bogie 2 will be described with reference to FIG.

First, since the front wheel 41F and the rear wheel 41R are fixed to the front wheel steering shaft 43F and the rear wheel steering shaft 43R with respect to the bogie 2, the front and rear wheel distance H _AGV is always constant. Therefore, as shown in FIG. 5, the small moving distance dl along the mounting shaft _{O PWS} of the carriage 2, and the small moving distance dl _F of the front wheels 41F, and small moving distance dl _R of the rear wheels 41R, between the The following equation (3) is established. In addition, in FIG. 5, in order to make an understanding easy, the micro movement distance dl is exaggerated and illustrated.

When the front wheel 41F and the rear wheel 41R move without idling, respectively, both the wheels 41F and 41R move on the circumference centered on the virtual turning center point R _AGV . Further, as shown in FIG. 5, the position of the turning center point R _{AGV is determined by} the position of the center point P _AGV of the bed 21, the front wheel steering angle _{F F,} and the rear wheel steering angle _{R R.} The front wheel turning radius R _F is the distance between the wheel turning radius R _R and the front wheel 41F and pivot point R _AGV after the distance between the rear wheels 41R and pivot point R _AGV each respective steering angle The following equations (4-1) and (4-2) are calculated using ρ _F and _{R R.}

Also the use of the front wheel turning radius _{R F} and small moving distance dl _F, relative small variation dψ of the vehicle body angle ψ of bed section 21, the following formulas (5-1) and (5-2) is derived. Therefore, the following equation (5-2) is an equation of motion with respect to the body angle of the truck 2.

As shown in FIG. 5, the minute change amount dP _F ^PWS of the position vector P _F ^PWS of the front wheel 41F in the mounting axis coordinate system and the minute change amount dP _R ^PWS of the position vector P _R ^PWS of the rear wheel 41R are respectively It becomes like 6-1) and (6-2).

Therefore, for the small variation dP _AGV ^PWS of the position vector P _AGV ^PWS in the mounting axis coordinate system of the center point P _AGV of the platform 21 which is the middle point of the front wheel 41F and the rear wheel 41R, the following equations (7-1) and (7-2) is derived. Therefore, the following equation (7-2) is an equation of motion of the position vector P _AGV ^PWS = [x _AGV ^PWS , y _AGV ^PWS ] in the mounting axis coordinate system.

The equation of motion shown in the above equation (7-2) is an equation of motion for the position vector P _AGV ^PWS in the mounting axis coordinate system based on the mounting axis. Therefore, the equation of motion for the position vector P _AGV ^AGV = [x _AGV ^AGV , y _AGV ^AGV ] in the major axis coordinate system multiplies the transformation matrix Q _AGV shown in the following equation (8-1) by the equation (7-2) Thus, the following equation (8-2) is derived.

Next, by introducing three parameters (α, β, γ), the equation of motion for the position and posture of the carriage 2 shown in the above equations (5-2) and (8-2) can be expressed by the following equation (9- Rewrite as shown in 1) and (9-2).

Here, the parameter γ is represented by the following equation (10) from the above equation (9-1).

From the above equations (9-1) and (9-2), the front wheel steering angle Δθ _F and the rear wheel steering angle Δθ _R are expressed by the following equations (11-1) and (11) using the parameters (α, β, γ) It can be expressed as 11-2). That is, assuming that the parameter α is the output of a feedback controller having the traveling error Δy as an input, and the parameter β is an output of a feedback controller having the posture error Δψ as an input, If the front wheel steering angle Δθ _F and the rear wheel steering angle Δθ _R are determined based on the non-interference operation shown in the following equations (11-1) and (11-2), the running error Δy and the attitude error Δψ are made independent. Means that it can be controlled.

  Next, referring to the block diagram of FIG. 6, a specific procedure for generating the front wheel speed command signal, the rear wheel speed command signal, the front wheel steering angle command signal, and the rear wheel steering angle command signal in the drive steering control unit 62 Explain.

The drive steering control unit 62 calculates the value of the minute movement distance dl along the attachment axis _OPWS of the carriage 2 and the angle parameter calculation unit 63 which calculates the value of the angle parameter γ defined by the equation (10). a small moving distance calculating unit 64, the front wheel speed value v _F ^* and the rear wheel velocity value v and the speed control unit 65 which calculates the _R ^*, front-wheel steering angle command value [Delta] [theta] _F ^* and the rear wheel steering angle command value [Delta] [theta] _R ^And a steering angle control unit 66 for calculating ^* .

Angle parameter calculation unit 63 sets a predetermined mounting angle φ _AGV , front wheel steering angle Δθ _F detected by front wheel steering angle sensor 47 _F, and rear wheel steering angle Δθ _R detected by rear wheel steering angle sensor 47 _R The value of the angle parameter γ is calculated by performing the calculation shown in the above equation (10) using

Speed control unit 65 calculates external speed command value v ^* , the value of angle parameter γ calculated by angle parameter calculation unit 63, front wheel steering angle Δθ _F detected by front wheel steering angle sensor 47F, and rear wheel steering angle a wheel steering angle [Delta] [theta] _R after being detected by the sensor 47R, by using a small moving distance _{dl F cosρ} F along the mounting shaft _{O PWS} front wheels 41F, minute along the mounting shaft _{O PWS} of the rear wheel 41R The front wheel speed command value v _F ^* and the rear wheel speed command value v _R ^* are calculated so that the movement distance dl _R cos _{R R} becomes equal, that is, the above equation (3) is satisfied. The speed control unit 65 also generates a front wheel speed command signal according to the calculated front wheel speed command value v _F ^* and a rear wheel speed command signal according to the rear wheel speed command value v _R ^* , and drives these command signals Input to units 4F and 4R.

More specifically, the speed control unit 65 performs the calculation shown in the following equation (12) based on the external speed command value v ^* , the angle parameter γ, and the detected steering angles _{F F} and _{R R.} It calculates a front wheel speed instruction value v _F ^* and the rear wheel speed value v _R ^* by.

The minute movement distance calculation unit 64 sets the attachment axis of the center point P _AGV of the carriage 2 for a minute time dt based on the value of the angle parameter γ calculated by the angle parameter calculation unit 63 and the external speed command value v ^*. Calculate the value of the small movement distance dl along O _PWS . More specifically, the minute movement distance calculation unit 64 calculates the value of the minute movement distance dl by performing calculation according to the following equation (13).

The steering angle control unit 66 uses the value of the minute movement distance dl calculated by the minute movement distance calculation unit 64, and the running error Δy and the attitude error Δ 検 出 detected by the shift detector 61 to obtain the running error Δy. The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated so that both the posture error Δ に な る become zero. The steering angle control unit 66 also generates a front wheel steering angle command signal and a rear wheel steering angle command signal according to the calculated front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^*. Are input to the drive units 4F and 4R.

More specifically, the steering angle control unit 66 includes a traveling error feedback controller 661, a posture error feedback controller 662, and a non-interference controller 663. By using these, the traveling error Δy and the posture error Δψ also the command value such that 0 Δθ _F ^*, and calculates the [Delta] [theta] _R ^*.

  The running error feedback controller 661 performs a calculation according to a known feedback control rule based on the running error Δy detected by the deviation detector 61 to make the first control input α such that the running error Δy becomes zero. The first control input α is generated and input to the non-interference controller 663.

More specifically, as shown in the following equation (14), the running error feedback controller 661 sets the first control input α in accordance with the PID control law that uses the minute movement distance dl calculated by the minute movement distance calculation unit 64 as a variable. Generate Here, in the following equation (14), the coefficients K _Py , K _Dy and K _Iy are PID control coefficients.

  The posture error feedback controller 662 performs a calculation according to a known feedback control rule based on the posture error Δψ detected by the deviation detector 61, thereby setting the second control input β to make the posture error Δψ 0. The second control input β is generated and input to the non-interference controller 663.

More specifically, the posture error feedback controller 662 sets the second control input β in accordance with the PID control law with the micro movement distance dl calculated by the micro movement distance calculation unit 64 as a variable as shown in the following equation (15) Generate Here, in the following equation (15), coefficients K _{P ψ} , K _{D ψ} and K I _ψ are PID control coefficients.

The non-interference controller 663 is controlled by the first control input α, the second control input β, a predetermined mounting angle φ _AGV, and the angle parameter calculator 63 so that the traveling error Δy and the attitude error Δψ do not interfere with each other. Based on the calculated value of the angle parameter γ, the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated. More specifically, the non-interference controller 663 performs the operation according to the following equations (16-1) and (16-2) derived using the above equations (11-1) and (11-2) The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated.

By the way, in consideration of convenience by the user, when both of the traveling error Δy and the attitude error Δψ are zero, the control inputs α and β which are the outputs of the respective feedback controllers 661 and 662 are both zero, and further non-interference It is preferable that the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* calculated by the controller 663 be parallel to a predetermined reference axis (for example, the main shaft O _{AGV of the} truck 2) . Therefore, the non-interference controller 663 performs front wheel steering angle command value Δθ _F ^* and rear wheel steering according to the following equations (17-1) and (17-2) instead of the above equations (16-1) and (16-2) The angle command value Δθ _R ^* may be calculated.

In the above equations (17-1) and (17-2), α ₀ is the integral constant in the above equations (9-1) and (9-2), and is determined using the mounting angle φ _AGV and the angle parameter γ as follows: It represents by Formula (18-1). Thereby, the said Formula (17-1) and (17-2) are rewritten by following formula (18-2) and (18-3). In the non-interference controller 663, the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated according to the following equations (18-2) and (18-3). When the control inputs α and β are 0, the front wheel 41F and the rear wheel 41R can be parallel to the main shaft O _AGV .

FIG. 7 is a view showing an example of the control result of the carriage 2 by the control device 6 as described above. More specifically, in FIG. 7, the position command value y ^* is changed stepwise at time t1 from the state (Δy = Δψ = 0) in which the vehicle is traveling according to the external position command signal and the external attitude command signal, Furthermore, after that, at time t2, when posture command value ψ ^* is changed in a step-like manner, it is a figure showing a time change of detected traveling position y _AGV ^AGV and detected posture ψ.

As shown in FIG. 7, when position command value y ^* is changed stepwise at time t1, shift detector 61 detects a travel error Δy which is a shift between detected travel position y _AGV ^AGV and position command value y ^*. The steering angle control unit 66 calculates the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* such that the detected travel error Δy becomes zero. As a result, the detected traveling position y _AGV ^AGV changes rapidly to follow the position command value y ^* .

After that, when the attitude command value ψ ^* is changed stepwise at time t2, the deviation detector 61 detects an attitude error Δψ which is a deviation between the detected attitude ψ and the attitude command value ψ ^*, and the steering angle control unit 66 The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated so that the detected attitude error Δψ becomes zero. As a result, the detected attitude 速 や か quickly changes so as to follow the attitude command value ψ ^* .

Here, as shown in FIG. 7, even if the position command value y ^* changes stepwise at time t1, the detected posture ψ hardly changes. Further, even if the attitude command value ψ ^* changes stepwise at time t2, the detected traveling position y _AGV ^AGV hardly changes. Therefore, according to the steering angle control unit 66 according to the present embodiment, by using the traveling error feedback controller 661, the attitude error feedback controller 662, and the non-interference controller 663, the traveling error Δy and the attitude error Δψ are controlled independently. It became clear that it was possible.

  According to the drive steering device 3 of the AGV according to the present embodiment, the following effects can be obtained.

(1) Drive steering device 3 drives deviation detector 61 and external position command signal (v ^* ), external position command signal (y ^* ), and external attitude command signal (ψ ^* ) using shift detector 61 as an external command. The front wheel speed command signal (v _F ^* ) and the front wheel steering angle command signal (Δθ _F ^* ) for the front wheel 41 _F and the rear wheel speed command signal (v _R for the rear wheel 41 _R are controlled by the steering control unit 62 based on these external commands. ^* ) And a rear wheel steering angle command signal (Δθ _R ^* ) are generated. In particular, in the deviation detector 61, a traveling error Δy between the detected traveling position y _AGV ^{AGV of} the platform 21 and the external position command value y ^* and a detected attitude ψ of the platform 21 and the external attitude command value ψ ^* At the drive steering control unit 62, the front and rear wheel steering angle command signals for the front wheel 41F and the rear wheel 41R are detected so that the running error .DELTA.y and the posture error .DELTA. Generate Δθ _F ^* , Δθ _R ^* ). As a result, the speed corresponding to the external speed command signal (v ^* ) is taken along the path according to the external position command signal (y ^* ) with the loading section 21 in the attitude according to the external attitude command signal (ψ ^* ) It can be run at That is, according to the drive steering device 3, the designated route can be made to travel at the designated speed while changing the carriage 2 in various postures according to the external posture command signal. It is possible to realize traveling with a higher degree of freedom than in the case where the position is limited.

(2) If the steering angles of the front wheel 41F and the rear wheel 41R are independently changed without providing any restraint condition, both the position and the posture of the bed portion 21 change. Therefore, in the drive steering device 3, the running error feedback controller 661 generates a first control input α according to the running error Δy, and the attitude error feedback controller 662 generates a second control input β according to the attitude error Δψ. Based on the first and second control inputs α and β, the front wheel and rear wheel steering angle command signals (Δθ _F ^* and Δθ _R ^* ) are calculated by the non-interference controller 663 so that the travel error Δy and the attitude error Δψ do not interfere. Generate As a result, according to the drive steering device 3, since the traveling error Δy and the attitude error Δψ can be controlled independently, traveling with a high degree of freedom can be realized smoothly.

(3) When the first and second control inputs α and β are both 0, that is, when there is no travel error Δy and attitude error Δψ, the non-interference controller 663 controls the front wheel steering angle command value Δθ _F ^* and the rear The front wheel and rear wheel steering angle command signals are generated such that the wheel steering angle command values Δθ _R ^* are both parallel to the reference axis. Thus, when there is no traveling error Δy and no posture error Δψ, the directions of the front wheel 41F and the rear wheel 41R can be aligned on a predetermined reference axis, and convenience can be improved.

(4) In the driving steering device 3, the front and rear wheel drive unit 4F, the 4R, mounting angle in the main shaft _{O AGV} and the center point _{P AGV} mounting axis _{O PWS} and bed portion 21 of the front wheel 41F and rear wheel 41R phi _AGV It attaches to the loading part 21 so that it inclines by. Thereby, the bogie 2 can be made to travel so that the front wheel 41F and the rear wheel 41R do not step on the guiding line L provided on the floor surface F. Further, by making the main axis O _AGV parallel to the basic traveling direction of the carriage 2 parallel to the reference axis as described above, when there is no travel error Δy and attitude error Δψ, the front wheel 41F and the rear wheel 41R Since the orientation can be made parallel to this basic traveling direction, the convenience can be further improved.

(5) The non-interference controller 663 calculates the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _F ^* according to the above equations (18-2) and (18-3). Thereby, it is possible to independently control the running error Δy and the attitude error Δψ, and further, when there is no running error Δy and the attitude error Δψ, the direction of the front wheel 41F and the rear wheel 41R is a basic traveling direction of the main axis O _AGV Can be aligned parallel to In addition, the convenience can be further improved.

(6) The minute movement distance calculation unit 64 calculates the minute movement distance dl along the attachment axis _OPWS based on the front wheel and rear wheel steering angle detection signals (Δθ _F , Δθ _R ). In addition, the running error and attitude error feedback controllers 661 and 662 generate the first and second control inputs α and β according to a feedback control rule using the minute movement distance dl as a variable. This allows the response to distance to be constant. In other words, the truck 2 can be traveled along a fixed route regardless of the speed.

(7) front and rear wheel drive unit 4F, since 4R is attached to the bed portion 21, the distance _{H AVG} along the mounting shaft _{O PWS} between the front wheel 41F and rear wheel 41R is always constant. Therefore, the speed control unit 65 makes the minute movement distance dl _F cos _{F F} along the attachment axis O _PWS of the front wheel 41 _F equal to the minute movement distance dl _R cos _{R R} along the attachment axis O _PWS of the rear wheel 41 _R. a component along the mounting shaft O _PWS velocity vector of the front wheel 41F in other words, as the component along the mounting shaft O _PWS velocity vector of the rear wheels 41R are equal, the front and rear wheels speed command signal (v _{By generating F} ^* and v _R ^* ), it is possible to prevent the front wheel 41F or the rear wheel 41R from idling and the application of an unreasonable force between the two wheels. Therefore, according to the drive steering device 3, wasteful consumption of electric power can be suppressed while realizing traveling with a higher degree of freedom than in the case where the position of the turning center is limited as in the prior art.

Second Embodiment
Next, a drive steering apparatus for an unmanned carrier according to a second embodiment of the present invention will be described with reference to the drawings. In the following, the same components as those of the drive steering apparatus according to the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

  FIG. 8 is a view showing a configuration of a control device 6A of the drive steering apparatus according to the present embodiment. The control device 6A according to the present embodiment differs from the control device 6 according to the first embodiment in the specific procedure of the drive steering control.

  First, with reference to the plan view of the carriage 2 of FIG. 9, the definition of various parameters and coordinate systems defined in the control device 6A for grasping the position and attitude of the carriage 2 will be described.

In the present embodiment, the direction in which the center point P _AGV of the carriage 2 _travels is referred to as the traveling direction of the carriage 2. Further, an axis parallel to the traveling direction and passing through the central point P _AGV is referred to as a traveling axis O _Δ . In the following, the angle between the advancing axis O _Δ and the mounting axis O _PWS is referred to as the advancing angle λ.

In the control device 6A, the position of the central point P _AGV of the carriage 2 is divided into two Cartesian coordinate systems of a traveling axis coordinate system (see solid arrows in FIG. 9) and a mounting axis coordinate system (see dashed arrows in FIG. 9). To grasp.

The attachment axis coordinate system is a coordinate system in which the X axis and the attachment axis _OPWS are parallel to each other and the front wheel 41F side of the attachment axis _OPWS is the positive side of the X axis, as in the first embodiment. . In the following, the position vector of the center point P _AGV in the mounting axis coordinate system is expressed as P _AGV ^PWS = [x _AGV ^PWS , y _AGV ^PWS ].

The traveling axis coordinate system is a coordinate system in which the X axis is parallel to the traveling axis O _{Δ of the} carriage 2 and the traveling direction, and the traveling direction of the carriage 2 is on the positive side. Hereinafter, the position vector of the central point P _AGV in the advancing axis coordinate system is denoted as P _AGV ^Δ = [x _AGV ^Δ , y _AGV ^Δ ]. The position vector of the mounting axis coordinate system and the position vector of the advancing axis coordinate system can be mutually converted by a conversion matrix Q _Δ shown in the following equation (19).

Therefore, using this transformation matrix Q _Δ , the equation of motion for the position vector P _AGV ^PWS in the mounting axis coordinate system (see the above equation (7-2)) is the position vector P _AGV ^Δ = [x _AGV in the advancing axis coordinate system ^It can be derived as shown in the following equation (20) as an equation of motion for ^Δ , y _AGV ^Δ ].

Further, by introducing three parameters (α, β, γ), the equation of motion for the position and posture of the carriage 2 shown in the above equations (5-2) and (20) can be expressed by the following equations (21-1) and It is rewritten as shown in 21-2).

Here, the parameter γ is represented by the following equation (22) from the above equation (21-1).

From the above equations (21-1) and (21-2), the front wheel steering angle Δθ _F and the rear wheel steering angle Δθ _R are expressed by the following equations (23-1) and (23) using the parameters (α, β, γ) It can be expressed as in 23-2). That is, assuming that the parameter α is the output of a feedback controller having the traveling error Δy as an input, and the parameter β is an output of a feedback controller having the posture error Δψ as an input, If the front wheel steering angle Δθ _F and the rear wheel steering angle Δθ _R are determined by the non-interference operation shown in the following equations (23-1) and (23-2), the running error Δy and the attitude error Δψ are made independent. Means that it can be controlled.

  Next, referring to the block diagram of FIG. 8, a specific procedure for generating the front wheel speed command signal, the rear wheel speed command signal, the front wheel steering angle command signal, and the rear wheel steering angle command signal in the drive steering control unit 62A. Explain.

Drive steering control unit 62A calculates the angle parameter calculation unit 63A which calculates the value of the angle parameter γ defined by the equation (22), the value of the small moving distance dl along the mounting shaft O _PWS of the truck 2 Small travel distance calculation unit 64A, advancing angle calculation unit 67A for calculating the value of advancing angle λ, speed control unit 65A for calculating front wheel speed command value v _F ^* and rear wheel speed command value v _R ^* , front wheel steering And a steering angle control unit 66A that calculates an angle command value Δθ _F ^* and a rear wheel steering angle command value Δθ _R ^* .

The advancing angle calculation unit 67A calculates the value of the advancing angle λ which is an angle formed by the advancing axis OA and the attachment axis _OPWS (see FIG. 9). More specifically, the advancing angle calculation unit 67A is an attitude command value that is a command value for the vehicle body angle ψ (the angle between the reference axis O _BS (that is, the reference tangent O _L of the induction line _L ) and the main axis O _AGV ). The value of the advancing angle λ is calculated according to the following equation (24) by using ψ ^* and a mounting angle φ _AGV which is an angle formed by the main axis O _AGV and the mounting axis O _PWS .

The angle parameter calculation unit 63A uses the front wheel steering angle Δθ _F detected by the front wheel steering angle sensor 47F and the rear wheel steering angle Δθ _R detected by the rear wheel steering angle sensor 47R to obtain the above equation (22). The value of the angle parameter γ is calculated by performing the calculation shown in FIG.

Speed control unit 65A uses external speed command value v ^* , front wheel steering angle Δθ _F detected by front wheel steering angle sensor 47F, and rear wheel steering angle Δθ _R detected by rear wheel steering angle sensor 47R. Thus, the minute movement distance dl _F cos _{F F} along the attachment axis O _PWS of the front wheel 41 _F and the minute movement distance dl _R cos _{R R} along the attachment axis O _PWS of the rear wheel 41 _R become equal, ie The front wheel speed command value v _F ^* and the rear wheel speed command value v _R ^* are calculated so that the equation (3) is satisfied. The speed control unit 65 also generates a front wheel speed command signal according to the calculated front wheel speed command value v _F ^* and a rear wheel speed command signal according to the rear wheel speed command value v _R ^* , and drives these command signals Input to units 4F and 4R.

More specifically, in the speed control unit 65A, the front wheel speed command is performed by performing the calculation shown in the following equation (25) based on the external speed command value v ^* and the detected steering angles _{F F} and _{R R.} the value _v ^{F *} and the rear wheel velocity value _v to calculate the ^{R *.}

The minute movement distance calculation unit 64A is detected by the value of the angle parameter γ calculated by the angle parameter calculation unit 63A, the front wheel steering angle Δθ _F detected by the front wheel steering angle sensor 47F, and the rear wheel steering angle sensor 47R. Based on the rear wheel steering angle Δθ _R , the front wheel speed v _F detected by the front wheel speed sensor 46 _F, and the rear wheel speed v _R detected by the rear wheel speed sensor 46 _R , the center of the truck 2 for a minute time dt The value of the minute movement distance dl along the mounting axis O _PWS of the point P _AGV is calculated. More specifically, the minute movement distance calculation unit 64A calculates the value of the minute movement distance dl by performing calculation according to the following equation (26).

The steering angle control unit 66A uses the value of the minute movement distance dl calculated by the minute movement distance calculation unit 64A, and the running error Δy and the attitude error Δ 算出 calculated by the deviation detector 61 to obtain a running error Δy. The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated so that both the posture error Δ に な る become zero. The steering angle control unit 66 also generates a front wheel steering angle command signal and a rear wheel steering angle command signal according to the calculated front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^*. Are input to the drive units 4F and 4R.

More specifically, the steering angle control unit 66A includes a traveling error feedback controller 661A, a posture error feedback controller 662A, and a non-interference controller 663A, and by using these, the traveling error Δy and the posture error Δψ also the command value such that 0 Δθ _F ^*, and calculates the [Delta] [theta] _R ^*.

  The running error feedback controller 661 A performs a calculation according to a known feedback control rule based on the running error Δy detected by the shift detector 61 to make the first control input α such that the running error Δy becomes zero. The first control input α is generated and input to the non-interference controller 663A.

More specifically, as shown in the following equation (27), the running error feedback controller 661A uses the first control input α in accordance with the PID control law with the minute movement distance dl calculated by the minute movement distance calculation unit 64A as a variable. Generate Here, in the following equation (27), the coefficients K _Py , K _Dy and K _Iy are PID control coefficients.

  Attitude error feedback controller 662 A performs a calculation according to a known feedback control rule based on attitude error Δψ detected by shift detector 61 to make a second control input β such that attitude error Δψ is zero. The second control input β is generated and input to the non-interference controller 663A.

More specifically, as shown in the following equation (28), the posture error feedback controller 662A uses the second control input β in accordance with a PID control rule that uses the minute movement distance dl calculated by the minute movement distance calculation unit 64A as a variable. Generate Here, in the following equation (28), coefficients K _{P ψ} , K _{D ψ} and K I _ψ are PID control coefficients.

The non-interference controller 663A is controlled by the first control input α, the second control input β, a predetermined attachment angle φ _AGV, and the angle parameter calculator 63A so that the traveling error Δy and the attitude error Δψ do not interfere with each other. The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated based on the calculated value of the angle parameter γ and the value of the advancing angle λ calculated by the advancing angle calculation unit 67A. Do. More specifically, the non-interference controller 663A performs the operation according to the following equations (29-1) and (29-2) derived using the above equations (23-1) and (23-2) The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* are calculated.

By the way, in consideration of convenience by the user, when both of the running error Δy and the attitude error Δψ are zero, the control inputs α and β which are the outputs of the respective feedback controllers 661A and 662A are both zero, and further non-interference The front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* calculated by the controller 663A may be parallel to a predetermined reference axis (for example, the advancing axis O _Δ of the carriage 2) preferable. Therefore, the non-interference controller 663A controls the front wheel steering angle command value Δθ _F ^* and the rear wheel steering according to the following equations (30-1) and (30-2) instead of the above equations (29-1) and (29-2) The angle command value Δθ _R ^* may be calculated.

In the above formulas (30-1) and (30-2), α ₀ is an integral constant in the above formulas (21-1) and (21-2), and using the advancing angle λ and the angle parameter γ, the following formula (31-1). Thereby, the above formulas (30-1) and (30-2) are rewritten by the following formulas (31-2) and (31-3). The non-interference controller 663A calculates the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value Δθ _R ^* according to the following equations (31-2) and (31-3) to obtain the feedback controllers 661A and 662A. When the control inputs α and β are 0, the front wheel 41F and the rear wheel 41R can be made parallel to the advancing axis O _Δ .

The above formulas (31-2) and (31-3) can be expressed by the following formulas (32-3) using the angles δ _F and δ _R defined by the following formulas (32-1) and (32-2). And (32-4) can also be rewritten.

  The drive steering apparatus according to the present embodiment has the following effects in addition to the effects of the above (1) to (7).

(8) In the drive steering apparatus, by making the advancing axis O _Δ of the loading platform 21 parallel to the reference axis, when there is no travel error Δy and posture error Δψ, the directions of the front wheel 41F and the rear wheel 41F are set. Since the alignment can be made parallel to the advancing axis O _Δ of the loading section 21, the convenience can be further improved.

(9) In the non-interference controller 663A, the front wheel steering angle command value Δθ _F ^* and the rear wheel steering angle command value according to the above equations (31-2) and (31-3) or (32-3) and (32-4) Calculate Δθ _F ^* . Thereby, the traveling error Δy and the attitude error Δψ can be controlled independently, and when there is no traveling error Δy and the attitude error Δψ, the directions of the front wheel 41F and the rear wheel 41R are parallel to the traveling axis O _Δ of the truck 2 The convenience can be further improved because it can be aligned.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to this. The detailed configuration may be changed as appropriate within the scope of the present invention.

1 ... unmanned transport vehicle 2 ... truck 21 ... loading platform (platform)
3 ... Drive steering device 4F ... Front wheel drive unit (first drive unit)
4R ... rear wheel drive unit (second drive unit)
41F ... front wheel (first drive steering wheel)
41R ... rear wheel (second drive steering wheel)
43F: front wheel steering shaft (first steering shaft)
43R ... rear wheel steering shaft (second steering shaft)
47F ... front wheel steering angle sensor (first steering angle detector)
47R ... rear wheel steering angle sensor (second steering angle detector)
6, 6 A: Control device 61: Deviation detector 62: Drive steering control unit (control device)
65, 65A ... speed control unit 66, 66A ... steering angle control unit 661, 661A ... running error feedback controller (first feedback controller)
662, 662 A ... attitude error feedback controller (second feedback controller)
663, 663A ... non-interference controller

Claims (10)

A drive steering apparatus for an unmanned carrier, which travels based on a predetermined external command, comprising:
A first drive unit attached to the base and driving the first drive steering wheel according to the first speed command and the first steering angle command;
A second drive unit attached to the base and driving a second drive steering wheel in accordance with a second speed command and a second steering angle command;
A displacement detector that detects the position and orientation of the pedestal, and outputs a positional deviation between the detected position and an external position command, and an attitude deviation between the detected attitude and an external attitude command;
And a controller configured to generate the first and second speed commands and the first and second steering angle commands based on the position shift, the attitude shift, and an external speed command.
The control apparatus includes a steering angle control unit that generates the first and second steering angle commands such that the positional deviation and the attitude deviation are eliminated. The steering angle control unit
A first feedback controller generating a first control input according to the positional deviation;
A second feedback controller that generates a second control input according to the attitude deviation;
And a non-interference controller that generates the first and second steering angle commands based on the first and second control inputs so that the positional deviation and the attitude deviation do not interfere with each other. The drive steering device of the unmanned carrier according to Item 1.   When the first control input and the second control input are both 0, the non-interference controller causes both the first steering angle command and the second steering angle command to be parallel to a predetermined reference axis. The drive steering apparatus for an unmanned transfer vehicle according to claim 2, wherein the first and second steering angle commands are generated. The mounting shaft connecting the first steering shaft of the first drive steering wheel and the second steering shaft of the second drive steering wheel and the main shaft of the base are inclined at a predetermined mounting angle at the center point of the base Yes,
The drive steering apparatus for an unmanned transfer vehicle according to claim 3, wherein the reference axis is parallel to the main axis. The non-interference controller sets the first control input as α, the second control input as β, an angle between the mounting shaft and the main shaft as φ _AGV, and the first steering shaft and the second steering shaft The first steering angle command Δθ _F ^* and the second steering angle command Δθ _R ^* are generated according to the following equation, with H _{AGV as} the distance along the mounting axis between them. Drive steering device for an unmanned carrier according to the invention.

  The drive steering apparatus for an unmanned transfer vehicle according to claim 3, wherein the reference axis is parallel to the advancing axis of the platform. The non-interference controller sets the first control input as α, the second control input as β, and connects a first steering axis of the first drive steering wheel and a second steering axis of the second drive steering wheel. _{Let the} angle between the mounting shaft and the main shaft be φ _AGV , let the distance along the mounting shaft between the first steering shaft and the second steering shaft be H _AGV, and let the advancing shaft and the mounting shaft 7. The drive steering system for an unmanned carrier according to claim 6, wherein the first steering angle command Δθ _F ^* and the second steering angle command Δθ _R ^* are generated according to the following equation, where λ is an angle formed.

A first steering angle detector that detects a steering angle of the first drive steering wheel and generates a first steering angle detection signal;
And a second steering angle detector that detects a steering angle of the second drive steering wheel and generates a second steering angle detection signal,
The control device includes a minute movement distance calculation unit configured to calculate an axial minute movement distance which is a minute movement distance of the base along the attachment axis based on the first and second steering angle detection signals.
The said 1st and 2nd feedback controller produces | generates the said 1st and 2nd control input according to the feedback control law which made the said axial small moving distance a variable, The 4th, 2nd, 3rd, 3rd The drive steering apparatus for an unmanned carrier according to claim 1. A first steering angle detector that detects a steering angle of the first drive steering wheel and generates a first steering angle detection signal;
And a second steering angle detector that detects a steering angle of the second drive steering wheel and generates a second steering angle detection signal,
The control device defines an axis connecting the first steering axis of the first drive steering wheel and the second steering axis of the second drive steering wheel as a mounting axis, and determines the first and second steering angle detection signals. A minute movement distance calculation unit configured to calculate an axial minute movement distance which is a minute movement distance of the platform along the mounting axis,
The said 1st and 2nd feedback controller produces | generates the said 1st and 2nd control input according to the feedback control law which made the said axial small movement distance a variable, The 2nd, 3rd, 6th in any one of the Claims 2 to 3 characterized by the above-mentioned. The drive steering apparatus for an unmanned carrier according to claim 1.   The control device is configured to make the first and the second driving steered wheels equal in minute travel distance along the attachment axis of the first drive steered wheel and in the second drive steered wheel along the attachment axis. 10. The drive steering apparatus for an unmanned transfer vehicle according to claim 8, further comprising a speed control unit that generates the first and second speed commands based on a steering angle detection signal and the external speed command.

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