JP2008126709A - Unmanned carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an unmanned carrier which eliminates distortion of a harness arranged between the upper and lower structures. <P>SOLUTION: The unmanned carrier 1 is equipped with a travel drive unit 2 which changes an advancing direction of a vehicle by turning in a plane an axle shaft 7 having driving wheels 11 provided at both ends thereof and independently driven by respective motors 8. The unmanned carrier 1 is further equipped with a spindle 3 which rotates the axle shaft 7 around its own shaft and supports the center to be turnable in the plane; axle shaft rotation means (21-26) for rotating the axle shaft 7 around its own axis extending in a longitudinal direction of the axle shaft 7 in accordance with the direction and amount of turn around the spindle 3 of the axle shaft 7; and a harness 12 passed through inside the spindle 3 from a control means arranged in a vehicle body upper structure of the vehicle, laid to the axial end of the axle shaft 7 from an end of the spindle 3 and connected to the respective motors 8 and a peripheral equipment 10 through inside the axle shaft 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an automatic guided vehicle capable of changing a course without changing a direction of a vehicle by changing a driving direction by a traveling drive unit, and in particular, straddling a traveling drive unit capable of changing a direction and a vehicle upper structure. The present invention relates to an automatic guided vehicle suitable for eliminating twisting of a power supply and signal harness arranged.

  2. Description of the Related Art Conventionally, there has been proposed an automatic guided vehicle capable of branching by switching the direction of a wheel to a branching direction without changing the direction of the automatic guided vehicle on a branch road where magnetic tapes intersect (see Patent Document 1).

This is an unrailed automatic guided vehicle that runs along a track laid on the floor surface, and a pair of left and right drive wheels are arranged so as to be capable of turning with a vertical support shaft and a turning bracket interposed in the center of the carriage frame. It is an unrailed automatic guided vehicle with caster wheels at the front and back, and a pair of left and right drive wheels around the center of the bogie frame by the vertical support shaft and swivel bracket while the bogie frame is fixed in the forward and backward running posture The direction of the driving wheel can be switched between front and rear traveling and transverse traveling by turning the vehicle.
JP-A-5-270396

  By the way, as in the above-described conventional example, in an automatic guided vehicle or a self-propelled robot provided with a pair of left and right drive wheels arranged to be rotatable with a vertical support shaft and a turning bracket interposed in a lower structure, a battery and a control device are provided. Because it is arranged in the upper structure, wiring between the lower structure and the upper structure that turns harnesses such as a power line that supplies power to the drive motor of the drive wheel and a signal line to the sensor that detects rotation of the drive wheel There is a need to. Since these harnesses are twisted when the lower structure turns, they may interfere with the road surface or the upper structure of the carriage, or may be caught in the drive wheels and disconnected. In particular, when the lower structure is largely swung, the above problem becomes significant. In order to eliminate the twist of the harnesses, it is conceivable to limit the turning range of the lower structure, but in that case, there is a problem that the direction changing function of the automatic guided vehicle or the self-propelled robot is limited. .

  Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an automatic guided vehicle suitable for eliminating twisting of harnesses arranged between upper and lower structures of a vehicle.

  The present invention relates to an automatic guided vehicle including a travel drive unit that is capable of changing a propulsion direction of a vehicle by turning an axle shaft that is provided with driving wheels independently driven by a drive motor at both ends in a plane. According to the direction and amount of the pivot of the axle shaft around the support shaft, and the support shaft that supports the central portion of the axle shaft so as to be rotatable around the longitudinal axis of the axle shaft and capable of turning in a plane. Axle shaft rotating means for rotating the axle shaft about its own axis extending in the longitudinal direction, and control means arranged in the vehicle body upper structure of the vehicle through the support shaft from the tip of the support shaft. And a harness connected to one of the shaft end sides and connected to the drive motor and peripheral devices from the shaft end of the axle shaft through the axle shaft.

  Therefore, in the present invention, the axle shaft can be rotated around the longitudinal axis of the axle shaft itself, and the central portion thereof is supported by the support shaft so as to be able to turn in a plane, and the turning direction of the axle shaft around the support shaft is supported. Depending on the amount, the axle shaft rotating means rotates the axle shaft about its own axis extending in the longitudinal direction, so that the tip of the supporting shaft passes through the inside of the supporting shaft from the control means arranged in the vehicle body superstructure. The axle shaft on the tip side of the power supply line connected to the drive motor of the drive wheel from the shaft end of the axle shaft to the shaft end side of the axle shaft is twisted to the harness. The twisting of the harness can be eliminated, and even if the axle shaft is swung continuously continuously, the harness is twisted and the road surface or the upper structure of the carriage is removed. Or interfere with, possible to prevent disconnection involved in the driving wheels. For this reason, the trouble of restricting the direction changing function of the automatic guided vehicle or the self-propelled robot by restricting the turning range of the axle shaft does not occur.

  Hereinafter, the automatic guided vehicle of the present invention is explained based on one embodiment shown in Drawings 1-8. 1 is a plan view showing a layout of a travel drive unit of an automatic guided vehicle, FIG. 2 is a schematic configuration diagram of the travel drive unit, FIGS. 3 and 4 are cross-sectional views showing details of the travel drive unit, and FIGS. Schematic diagram and control block diagram for explaining the direction change control of the travel drive unit, FIGS. 7 and 8 are explanatory diagrams for explaining the operation of the travel reaction force support mechanism of the travel drive unit of this embodiment and the comparative example, FIG. These are the figures explaining the vector structure of the driving | running | working reaction force support mechanism of this embodiment.

  In FIG. 1, an automatic guided vehicle 1 according to this embodiment includes four sets of traveling drive units 2 positioned at respective corners of a lower portion of a vehicle body 1A constituting an upper structure. As shown in FIG. 2, the travel drive unit 2 includes a support shaft 3 that is fixed upright from the vehicle body 1A toward the floor, an arm 5 that is pivotally supported by the support shaft 3, and a tip thereof. An offset arm 4 having a longitudinal axis 6 that protrudes downward from the longitudinal axis of the offset arm 4 and a central portion in the longitudinal direction that is disposed in a lateral direction orthogonal to the longitudinal axis 6 of the offset arm 4 and is rotatable about an axis extending in the longitudinal direction. Axle shaft 7 that is pivotally supported by vertical axis 6, and arranged at both ends of axle shaft 7, drive motor 8, reduction gear 9, and motor encoder 10 of drive motor 8 are built in, and drive from built-in drive motor 8 is performed. Drive wheels 11 driven by a force through a speed reducer 9.

  As shown in FIG. 1, the offset arm 4 and the axle shaft 7 can pivot together on a plan view. A harness 12 such as a power line to the left and right drive motors 8 and a signal line from each motor encoder 10 is provided in a harness protector (not shown) that is passed between the shaft end of the axle shaft 7 and the shaft end of the support shaft 3. It is connected to a controller and a battery (not shown) disposed in the upper structure via the support shaft 3.

  In the traveling drive unit 2, a bevel gear 21 </ b> A fixed to the axle shaft 7 and a bevel gear 21 </ b> B arranged so as to be rotatable around the vertical axis 6 of the offset arm 4 are meshed with a gear ratio of “1”. ing. A belt 26 is wound around a pulley 24 fixed to a hollow shaft 23 connected to a bevel gear 21 </ b> B rotatably provided around the longitudinal axis 6 and a pulley 25 fixed to the support shaft 3. : 1 pulley ratio. These bevel gears 21A and 21B and the pulley winding portions 24 to 26 constitute an axle shaft rotating mechanism. Although the axle shaft 7 and the hollow shaft portion 23 disposed rotatably around the longitudinal axis 6 of the offset arm 4 have been described for transmitting rotation via the bevel gears 21A and 21B, Any other means may be used as long as both are rotationally conductive at 1: 1. In addition, the hollow shaft portion 23 and the support shaft 3 have been described as transmitting rotations using the pulleys 24 and 25 and the winding belt 26. However, gears are fixed to the hollow shaft portion 23 and the support shaft 3, respectively. These gears may be engaged with each other via an idler gear.

  The cross-sectional view of the travel drive unit 2 shown in FIG. 3 is a cross-sectional view including the center of the support shaft along the line AA in FIG. As shown in FIG. 3, the support shaft 3 is formed in a hollow shape and is fixed to the vehicle body 1A, and supports the arm portion 5 of the offset arm 4 through a pair of bearings 4A so as to be pivotable. The pulley 25 is fixed so as not to rotate. A harness 12 such as a power line or a signal line connected to a controller (not shown) and a battery, which is arranged in the upper structure, is inserted into the hollow hole of the support shaft 3 and passes through the harness protector 12A from the lower opening end to the axle shaft. 7 enters the axle shaft 7 from the shaft end and is electrically connected to the motor 8 and the motor encoder 10 arranged inside each drive wheel 11.

  When the travel drive unit 2 turns about the support shaft 3, the pulley 27 is integrally fixed to the end of the offset arm 4 on the support shaft 3 side, and the other end of the belt 28 wound around the pulley 27 is connected to the steering encoder 29. By winding it around the detection pulley 30, it can be detected by the steering encoder 29, and the detected turning angle signal is output to the controller.

  The cross-sectional view of the travel drive unit 2 shown in FIG. 4 is a cross-sectional view including the center of the vertical axis 6 and the axle shaft 7 along the line BB in FIG. As shown in FIG. 4, the vertical axis 6 of the offset arm 4 includes a lower shaft 6 </ b> A that rotatably supports the center portion of the axle shaft 7 via a bearing, and an upper shaft connected to the lower shaft 6 </ b> A via a pin 13. 6B. The upper shaft 6B is divided into an upper portion 6B1 and a lower portion 6B2 in the axial direction, and is combined in a nested manner. The upper shaft 6B is extended and biased by a suspension spring 14 inserted therein. The suspension spring 14 absorbs an impact when the driving wheel 11 is moved up and down by the unevenness of the floor surface during traveling by the driving wheel 11. A hollow shaft 23 integrally provided with a pulley 24 is rotatably supported on a divided upper shaft 6B of the vertical axis 6 via a bearing. Further, a hollow bevel gear 21 </ b> B formed in a hollow shape is rotatably supported on a lower shaft 6 </ b> A connected via a pin 13 of the vertical axis 6 via a bearing. The bevel gear 21B and the hollow shaft 23 provided with the pulley 24 are connected via a flexible bellows 22 so as to allow relative movement in the axial direction of the both, but to rotate integrally in the rotational direction. Yes. The bevel gear 21 </ b> B is configured to mesh 1: 1 with a bevel gear 21 </ b> A fixed to the axle shaft 7.

  Although a detailed mechanism is not shown inside the drive wheel 11, a stator of the drive motor 8 is disposed on the inner periphery and fixed to the axle shaft 7, and a driving force is applied to the reduction gear 9 on the outer periphery. A rotor is arranged so that output is possible. The drive motor 8 is not limited to the above-described structure, but any drive motor 8 may be used as long as the drive reaction force from the output unit is received by the axle shaft 7. The reduction gear 9 decelerates the driving force output from the motor 8 and transmits it to the driving wheel 11 as a rotational driving force. Since the reduction gear 9 is arranged in an annular space excluding the space occupied by the drive motor 8 arranged around the axle shaft 7 in the drive wheel 11, it is desirable to use the reduction gear 9 by a planetary gear mechanism. The rotation of the drive motor 8 is detected by the motor encoder 10 and fed back to the controller.

  In the axle shaft rotating mechanism having the above-described configuration, when the axle shaft 7 and the offset arm 4 turn around the support shaft 3 in accordance with a steering operation described later, the pulley 24 supported on the longitudinal axis 6 is supported. Since the belt 26 is wound around the pulley 25 fixed to the shaft 3, only the revolution around the support shaft 3 is allowed, and the hollow shaft 23 and the bevel gear 21B also revolve in the same manner (the direction of the hollow shaft 23 is determined in advance). Only in the set direction, the direction does not change by turning). That is, the hollow shaft 23 is rotated in a direction opposite to the direction in which the offset arm 4 turns, and is rotated in a direction to return a relative rotational difference of the hollow shaft 23 with respect to the support shaft 3. Then, when the offset arm 4 makes a round around the support shaft 3, the hollow shaft 23 is rotated at a rate of just one rotation in a direction to return relative rotation with respect to the support shaft 3. The rotation of the hollow shaft 23 is transmitted to the axle shaft 7 by meshing of the bevel gears 21A and 21B, and the axle shaft 7 is similarly opposite to the twist when the offset arm 4 makes a full turn around the support shaft 3. It will be rotated once to the side. Accordingly, the harness protector 12A that accommodates and connects the support shaft 3 and the axle shaft 7 with the harnesses 12 does not cause a relative rotational difference at both ends. It is prevented from occurring.

  The driving direction of the vehicle by the travel drive unit 2 is that the axle shaft 7 does not turn around the support shaft 7 when both the drive wheels 11 are driven at a constant speed by the drive motor 8 respectively. The support shaft 3 is pushed through the axle shaft 7 in a direction (driving direction) orthogonal to the vehicle, and the vehicle is moved. In this case, the combined forces in the driving direction of both drive wheels 11 are matched. When the average speed of both the drive wheels 11 becomes zero, that is, when both the drive wheels 11 are driven at the same speed in opposite directions, the axle shaft 7 and the offset arm 4 are moved around the support shaft 3. It is possible to change the driving direction to the support shaft 3 (steering operation, steering operation) by rotating. When the driving speed of the left and right drive wheels 11 is different, the support shaft 3 is rotated according to the average speed of the drive wheels 11 while rotating the axle shaft 7 and the offset arm 4 around the support shaft 3. It is also possible to drive the vehicle by pushing the button.

  FIG. 5 shows the detection procedure by the rotation detection sensors 10 and 29 provided in the travel drive unit 2, and the direction indicated by each arrow is positive, and the direction opposite to the arrow is negative. FIG. 6 shows a control block for the steering operation of the travel drive unit 2. Hereinafter, the steering operation of the traveling drive unit 2 in the automatic guided vehicle 1 of the present embodiment will be described based on the control block shown in FIG.

  The rotation angles θ 1 and θ 2 of the drive motor 8 are detected by the motor encoders 10, and the turning angle θs of the offset arm 4 is detected by the steering encoder 29. Since the rotation angles θ1 and θ2 of the drive motors 8 include the rotation component θs around the axle shaft 7 of the axle shaft 7 itself caused by the turning of the offset arm 4, the rotation of the axle shaft 7 is blocked in the blocks B1 and B2. An addition correction and a subtraction correction of the rotation component θs around the axis are executed, and each actual rotation angle is calculated. Further, the angular velocities (dθ1 / dt, dθ2 / dt) of each motor 8 and the steering angular velocity (dθs / dt) by the offset arm 4 are calculated by the blocks C1, C2, Cs, and the axes of the axle shaft 7 are calculated in the blocks D1, D2. Addition correction and subtraction correction of the surrounding angular velocity components (dθs / dt) are executed, and each actual angular velocity is calculated. In the block E1, the angular position of the travel drive unit 2 is always estimated based on the calculation results of the blocks B1, B2, D1, and D2.

  Therefore, when a target angular position command (for example, an angle signal with the left steering direction being positive and the right steering direction being negative with reference to when the vehicle is going straight) is given in block E3, in block E3, the target angular position command and the block A difference from the estimated angle position value from E1 is calculated, and each drive motor 8 is driven according to the difference, and control is performed so that the estimated angle position value reaches the target angle position command.

  Therefore, when the command angle position by the target angle position command E2 is changed, the left and right drive motors 8 are differentially controlled so that the new command angle position is obtained, and the steering angle of the travel drive unit 2 is changed to the axle shaft 7. The rotation is controlled while weaving the rotation around the longitudinal axis. Further, even when the vehicle is traveling while maintaining the command angle position based on the target angle position command E2, even if there is a possibility of disturbance in the traveling direction due to disturbance from the road surface, the axle shaft 7 The direction of travel can be maintained while weaving rotation about the longitudinal axis.

  The traveling direction of the vehicle can be changed variously according to the respective driving directions of the traveling drive units 2 arranged at the four corners of the vehicle.

  When the vehicle is moved straight, these travel drive units 2 are all steered in the same direction (front, rear, lateral, diagonal, etc.) to drive the drive wheels 11 at the same speed in the same direction. This makes it possible to drive the vehicle straight in that direction without changing the posture (orientation). A state indicated by a solid line in FIG. 1 indicates a case where the vehicle is driven forward, and a state indicated by a broken line indicates a case where the vehicle is driven laterally without changing its posture.

  When turning the vehicle, the steering angle of each traveling drive unit 2 (for example, the front left and right if it is a large turn) so that the extension line of each axle shaft 7 intersects at the center (turning center) to turn. Only the travel drive unit 2 is steered, and if it is a small turn, the front and rear travel drive units 2 are steered), and the drive speed of each drive wheel 11 is controlled so as to obtain an angular steering angle, thereby turning the vehicle. be able to.

  When the vehicle is turned on the spot, the steering angle position of each traveling drive unit 2 is calculated so that the vehicle center is the turning center, and each traveling drive unit 2 is controlled to the required steering angle. The vehicle can be turned on the spot by driving each driving wheel 11 of each traveling drive unit 2 at a constant speed.

  In the automatic guided vehicle 1 of the present embodiment, as shown in FIG. 1, the bevel gear 21 </ b> A disposed on the axle shaft 7 is disposed between the left and right traveling drive units 2 between the left and right traveling drive units 2. Are arranged on the right side (center side in the vehicle left-right direction), and the connection port to the axle shaft 7 of the harness protector 12A of the harnesses 12 connected to the support shaft 3 is also arranged on the right side (center side in the vehicle left-right direction). On the other hand, in the front and rear traveling drive units 2, the bevel gear 21 </ b> A disposed on the axle shaft 7 is disposed on the left side (center side in the vehicle left-right direction), and the axle of the harness protector 12 </ b> A of the harnesses 12 connected to the support shaft 3. The connection port to the shaft 7 is also arranged on the left side (center side in the vehicle left-right direction). That is, the left and right traveling drive units 2 of the vehicle are arranged symmetrically on the left and right.

  The rotation of the axle shaft 7 around the axis associated with the turning of the offset arm 4 is such that the bevel gear 21A on the axle shaft 7 side is arranged on the right side which is the vehicle center side in the left traveling drive unit 2, while In the drive unit 2, the bevel gear 21 </ b> A on the axle shaft 7 side is arranged on the left side which is the center side of the vehicle, so that the left and right traveling drive units 2 can be in opposite directions, and as a result, the respective axle shafts 7. The harness protector 12 </ b> A of the harness 12 that is connected to the support shaft can be connected from the vehicle center side end face.

  By the way, in the automatic guided vehicle 1 of this embodiment, in the state shown in a plan view, the offset arm 4 is inclined to the side where the bevel gear 21 </ b> A disposed on the axle shaft 7 is not orthogonal to the axle shaft 7. The axis of the support shaft 3 is offset from the axis of the longitudinal axis 6 in the direction of the axle shaft 7 by a distance S2.

  That is, between the left and right traveling drive units 2, in the left and right traveling drive units 2, the support shaft 3 is offset to the right side (the center side in the vehicle left and right direction) with respect to the axle shaft 7, In the travel drive unit 2, the support shaft 3 is offset to the left side (center side in the vehicle left-right direction) with respect to the axle shaft 7.

  FIG. 7 shows the traveling drive unit 2 in the left front of the vehicle. FIG. 8 shows a comparative example in which the offset arm 4 is laid out at right angles to the axle shaft 7. When a driving force in the forward direction C is applied to the driving wheel 11 of the traveling driving unit 2 shown in FIGS. 7 and 8 by the driving motor 8, a reaction force against the driving force of the driving wheel 11 is applied to the axle shaft 7. This reaction force acts in the direction of rotating the axle shaft 7 in the direction opposite to the driving force (in the direction of arrow D in the figure), and this acting force is transmitted to the hollow shaft 23 by the meshing of the bevel gears 21A and 21B. It acts to rotate the pulley 24 (see arrow E). The rotational force applied to the pulley 24 increases the tension on one side (right side in the illustrated example) of the belt 26 and decreases the tension on the other side (left side). Due to this unbalanced belt tension, a moment is generated which causes the offset arm 4 to turn in the direction of arrow F (here, counterclockwise).

  In the comparative example shown in FIG. 8, since there is no acting force to cancel the turning moment of the offset arm 4, the offset arm 4 rotates about the support shaft 3 in the counterclockwise direction in FIG. The traveling direction of the vehicle is changed to the left front, and the course of the vehicle changes in the direction of arrow G.

  However, in the traveling drive unit 2 shown in FIG. 7 according to the present embodiment, since the support shaft 3 and the longitudinal axis 6 are offset S2 in the lateral direction, the driving force of the drive wheels 11 acts and the axle shaft 7 Is pushed to the support shaft 3 side (the left and right drive wheels 11 have a force in the forward direction equivalent to the drive force acting on the road surface), the moment due to the drive in the direction of arrow H obtained by multiplying this forward force by the offset S2 is generated. appear. The moment H due to this driving is opposite to the turning moment F of the offset arm 4, and they cancel each other, so that the offset arm 4 does not turn and the traveling direction of the traveling drive unit 2 is the vehicle. Maintained in forward direction J. Here, the traveling drive unit 2 on the front left side of the vehicle has been described as a representative. However, the direction of each moment is also reversed in other traveling drive units 2, for example, the traveling drive unit 2 on the right front. Then, the traveling direction of the vehicle is maintained in the forward direction.

  FIG. 9 is a schematic diagram of the travel drive unit 2 (the right travel drive unit 2), and a method for setting the offset S2 of the support shaft 3 will be described below. Here, the radius of the drive wheel 11 is “r”, the center point of both drive wheels 11 is “O1”, the distance from the center point to the ground point of the drive wheel 11 is “d”, and the two offsets are “S1, S2”, respectively. ”, The support shaft 3 is“ O2 ”. The driving force applied to the road surface from the drive wheels 11 is “f”.

  As shown in FIG. 6, the traveling drive unit 2 is actively driven with the left and right drive wheels 11 controlled, and assumes the ideal state in which the torque of the left and right drive wheels 11 is balanced. When driving, the vehicle rotates at the same speed V, and the traveling drive unit 2 goes straight at V. The output torque M1 of the drive wheel 11 is M1 = f · r.

  The rotational moment N2 with respect to the support shaft O2 due to the propulsive force f of the drive wheel 11 can be expressed as N2 = f (d + S2) −f (d−S2) = 2f · S2, and this rotational moment N2 is represented by the traveling drive unit. 2 tends to be clockwise.

  On the other hand, the counter torque M′1 with respect to the output torque of the drive wheel 11 acts to rotate the axle shaft 7 around the axis, and acts on the pulley 24 fixed to the hollow shaft 23 via the bevel gear 21 and the hollow shaft 23. Then, it acts on the support shaft 3 via the belt 26 as a rotational moment N1.

  The rotational moment N1 with respect to the support shaft O2 is N1 = 2M′1 = 2 (f · r) (note: since it is torque by the two drive wheels 11), this rotational moment N1 is The travel drive unit 2 tends to rotate counterclockwise.

  In order to balance and cancel the rotational moment N1 and the rotational moment N2, it is necessary to set N1 = N2, that is, 2f · r = 2f · S2. Therefore, the offset S2 = the driving wheel radius r can be canceled out.

  In the above-described embodiment, the axle shaft rotating means for rotating the axle shaft 7 around its own axis extending in the longitudinal direction by the same angle as the turning amount in response to the turning of the axle shaft 7 around the support shaft 3. As described above, although a pair of pulleys 24, 25, a belt 26 and a bevel gear 21 are used, although not shown in the figure, for example, around the horizontal axis perpendicular to the longitudinal direction of the offset arm 4 at the tip of the offset arm 4 A pair of turnable direction change pulleys can be arranged, and a pulley fixed to the support shaft 3 and a cog belt or the like can be wound around these pulleys and the axle shaft 7. Crossed helical gears that mesh with each other at a gear ratio of 1: 1 may be disposed at a portion where the crossing points.

  In the above embodiment, the traveling drive unit 2 has been described in which the axle shaft 7 and the support shaft 3 intersect with each other while being offset by the offset arm 4. It may be.

  In the above-described embodiment, the automatic guided vehicle 1 has been described in which the traveling drive units 2 are arranged so as to be able to turn at the four corners. A caster wheel may be arranged, a traveling drive unit may be arranged to be able to turn at the center, and caster wheels may be arranged at four corners.

  In the present embodiment, the following effects can be achieved.

  (A) In the automatic guided vehicle 1 including the traveling drive unit 2 that can change the propulsion direction of the vehicle by turning the axle shaft 7 having driving wheels 11 that are independently driven by the drive motor 8 at both ends in a plane. The axle shaft 7 is rotatable about the longitudinal axis of the axle shaft 7 itself and supports a central portion of the axle shaft 7 so as to be rotatable in a plane. Axle shaft rotating means (21-26) for rotating the axle shaft 7 around its own axis extending in the longitudinal direction according to the direction and amount of turning, and control means arranged in the vehicle body upper structure of the vehicle The drive motor 7 and peripheral devices are passed through the support shaft 3 from the tip end of the support shaft 3 to the shaft end side of the axle shaft 7 and from the shaft end of the axle shaft 7 through the axle shaft 7. To 10 It comprises a harness 12 to be continued, the.

  That is, by rotating the axle shaft 7 around its own axis extending in the longitudinal direction by the axle shaft rotating means (21 to 26) according to the turning direction and amount of the axle shaft 7 around the support shaft 3, the vehicle From the control means disposed in the upper structure of the vehicle body through the support shaft 3 to the shaft end side of the axle shaft 7 from the tip of the support shaft 3, and from the shaft end of the axle shaft 7 to the axle shaft 7 The axle shaft 7 on the distal end side of the harness 12 connected to the drive motor 8 of the drive wheel 11 is always rotated in a direction to eliminate the twist of the harness 12, and the twist of the harness 12 can be eliminated. Even if the axle shaft 7 is swung continuously and greatly, it is possible to prevent the harness 12 from being twisted and interfering with the road surface or the upper structure of the carriage, or being caught in the drive wheel 11 and being disconnected. For this reason, the malfunction of restrict | limiting the turning range of the axle shaft 7 and restrict | limiting the direction change function of an automatic guided vehicle or a self-propelled robot does not generate | occur | produce. Further, since the axle shaft 7 is provided with driving wheels 11 that are rotationally driven by the driving motor 8 at both ends, the axle shaft 7 can be turned by making the both driving wheels 11 differential, and the traveling direction of the vehicle can be changed. It can be changed freely.

  (A) As the axle shaft rotating means (21-26), the axle shaft rotates about the vertical axis in the direction opposite to the turning direction and at an angle corresponding to the turning amount in accordance with the turning of the axle shaft 7 with respect to the support shaft 3. For example, the rotating member is arranged by fixing a pulley 25 or a gear fixed to the support shaft 3, while the pulley 24 or the gear having the same diameter is also fixed as the rotating member, and both are fixed by a belt 26 or an idler gear. It can be constructed by connecting it so that it can be transmitted, and the direction of rotation of the rotating member is changed to turn around the horizontal axis (for example, by a bevel gear 21 having a gear ratio of 1: 1 or an umbrella-shaped friction wheel) and an axle. By comprising the conversion mechanism that transmits to the shaft 7, the twist of the harness 12 can be eliminated even when the propulsion direction by the traveling drive unit 2 is continuously changed. That.

  (C) The travel drive unit 2 includes an axle shaft 7 rotatably supported on the tip of an offset arm 4 rotatably disposed on the support shaft 3, and the axle shaft 7 The rotating means (21 to 26) is disposed at the tip end portion of the offset arm 4 so as to be rotatable around an axis parallel to the support shaft 3, and reverses depending on the turning angle of the offset arm 4 around the support shaft 3. A rotating member 24 that is rotated in the direction and at an angle corresponding to the turning amount, a bevel gear 21B that rotates together with the rotating member 24, and a bevel gear 21A that is fixed to the axle shaft 7 so as to mesh with the bevel gear 21B. By providing the conversion mechanism thus configured, the travel drive unit 2 can be turned instantly without causing twisting or temporarily stopping of the harness 12, and holon such as forward / backward movement, left / right translation, and turning. Click (holonomic) to the omnidirectional can change the propulsion direction.

  (D) The axle shaft 7 is urged to rotate about its own axis by the driving reaction force of the drive wheel 11 held by the axle shaft 7, thereby causing the support shaft 3 to pass through the conversion mechanism and the rotating member. By arranging the axle shaft 7 to be inclined in a plane with respect to the offset arm 4 in a direction that cancels the turning moment to turn around, the driving reaction force against the drive wheels 11 fluctuates at the time of starting and at the time of acceleration. Even during deceleration, turning of the axle shaft 7 due to the driving reaction force is suppressed, and the vehicle can travel stably in the propulsion direction.

  (E) The support shaft 3 is offset in the direction of the axle shaft 7 by the radial dimension of the drive wheel 11 with respect to the central portion of the axle shaft 7 that is supported and connected to the offset arm 4. The propulsion direction does not change even when starting, accelerating, decelerating, etc., in which the turning of 7 is surely offset and the driving reaction force against the driving wheel 11 fluctuates.

  (F) The travel drive unit 2 includes a steering angle detection means 29 that detects the turning angle θs in the plane of the axle shaft 7 and a motor that detects the rotation angles θ1 and θ2 of the left and right drive motors 8 with respect to the axle shaft 7. An encoder 10 and a control means for controlling the rotation angle of the left and right drive motor 8, wherein the control means adds the detected steering angle θs to either the left or right detection motor rotation angle θ1, and the other The actual motor rotation angle obtained by subtracting the detected motor rotation angle θ2 and the detected angular velocity component of the steering angle θs are added to the angular velocity component of one detected motor rotation angle θ1, and the other Travel driving based on each actual motor rotational angular velocity obtained by subtracting the angular velocity component of the detected motor rotational angle θ2 and the angular velocity component of the steering angle θs. Estimating the angular position of the knitting 2, the estimated angular position is respectively controlling the left and right driving motor 8 so that the target angle position command. For this reason, when the command angle position by the target angle position command E2 is changed, the left and right drive motors 8 are differentially controlled so that the new command angle position is obtained, and the steering angle θs of the travel drive unit 2 is changed to the axle. It is controlled while incorporating the rotation of the shaft 7 around the longitudinal axis. Further, even when the vehicle is traveling while maintaining the command angle position based on the target angle position command E2, even if there is a possibility of disturbance in the traveling direction due to disturbance from the road surface, the axle shaft 7 It is possible to run without disturbing the traveling direction while incorporating the rotation around the longitudinal axis.

  Although the present invention has been described with respect to an embodiment for an automatic guided vehicle, the present invention can also be applied to a mobile robot that horizontally moves in various directions by a traveling drive unit.

The top view which shows the layout of the traveling drive unit of the automatic guided vehicle which shows one Embodiment of this invention. The schematic block diagram of a traveling drive unit similarly. Sectional drawing which shows the detail of the traveling drive unit in alignment with the AA cross section of FIG. Sectional drawing which shows the detail of the traveling drive unit which follows the BB cross section of FIG. Schematic explaining the direction change control of the travel drive unit. The control block diagram explaining the control of the direction change of a traveling drive unit. Explanatory drawing explaining the effect | action of the traveling reaction force support mechanism of a traveling drive unit. Explanatory drawing explaining the effect | action of the traveling reaction force support mechanism of the traveling drive unit of a comparative example. The figure explaining the vector structure of the driving | running | working reaction force support mechanism of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic guided vehicle 2 Travel drive unit 3 Support shaft 4 Offset arm 5 Arm 6 Vertical axis 7 Axle shaft 8 Drive motor 9 Deceleration mechanism 10 Motor encoder 11 Drive wheel 12 Harness

Claims (8)

In an automatic guided vehicle including a traveling drive unit capable of changing a propulsion direction of a vehicle by turning an axle shaft having driving wheels driven at each end independently by a driving motor in a plane,
A support shaft that can rotate the axle shaft around a longitudinal axis of the axle shaft itself and pivotally support the axle shaft in a plane;
Axle shaft rotating means for rotating the axle shaft around its own axis extending in the longitudinal direction according to the direction and amount of turning of the axle shaft around the support shaft;
The control means arranged in the vehicle body superstructure of the vehicle passes through the support shaft from the tip of the support shaft to one of the axle shaft ends, and passes through the axle shaft from the axle end of the axle shaft. And a harness connected to the drive motor and peripheral devices.   The axle shaft rotating means includes a rotating member that rotates in the direction opposite to the turning direction and at an angle corresponding to the turning amount around the vertical axis according to the turning of the axle shaft with respect to the support shaft, and the rotation of the rotating member The automatic guided vehicle according to claim 1, further comprising: a conversion mechanism that converts the direction of rotation into a rotation about a horizontal axis and transmits the rotation to the axle shaft.   The unmanned conveyance according to claim 1 or 2, wherein the traveling drive unit changes the traveling direction of the vehicle by causing the axle shaft to turn in a plane by making the pair of drive motors differential. car. The travel drive unit has an axle shaft supported at the tip of an offset arm rotatably arranged on the support shaft so as to be rotatable about the axis of the axle shaft itself.
The axle shaft rotating means is disposed at the tip of the offset arm so as to be rotatable around an axis parallel to the support shaft, and in a reverse direction and in a turning amount according to a turning angle around the support shaft of the offset arm. A rotating member that is driven to rotate at a corresponding angle, a bevel gear that rotates together with the rotating member, and a conversion mechanism that includes a bevel gear fixed to the axle shaft so as to mesh with the bevel gear. The automatic guided vehicle according to any one of claims 1 to 3.   The support shaft is provided with a pulley or gear fixed, the rotating member is constituted by a pulley or a gear, and the pulley or gear provided on the support shaft is connected to the rotating member by a belt or idler gear so as to be capable of transmission. The automatic guided vehicle according to any one of claims 2 to 4, wherein the automatic guided vehicle is provided.   The axle shaft is turned around its own axis through the conversion mechanism and the rotary member by being urged to rotate about its own axis by the driving reaction force of the drive wheel held by the axle shaft, thereby turning around the support shaft. 6. The automatic guided vehicle according to claim 4, wherein an axle shaft is inclined with respect to the offset arm in a plane in a direction in which the offset is offset.   7. The support shaft according to claim 4, wherein the support shaft is offset in a direction of the axle shaft by a radial dimension of the drive wheel with respect to a central portion of the axle shaft supported and connected to the offset arm. The automatic guided vehicle as described in one. The travel drive unit includes a steering angle detection unit that detects a turning angle in a plane of the axle shaft, a motor rotation angle detection unit that detects a rotation angle of the left and right drive motors with respect to the axle shaft, and a rotation of the left and right drive motors Control means for controlling the angle,
The control means detects each actual motor rotation angle obtained by adding the detected steering angle to either the left or right detection motor rotation angle and subtracting it from the other detection motor rotation angle. The actual angular speed component of the steering angle is obtained by adding the angular velocity component of the detected steering angle to the angular velocity component of one detected motor rotational angle and subtracting it from the angular velocity component of the other detected motor rotational angle. 8. The angular position of the traveling drive unit is estimated based on the angular velocity component, and the left and right drive motors are controlled so that the estimated angular position becomes a target angular position command. The automatic guided vehicle as described in any one of.