JP2017228158A - Unmanned conveyance system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an unmanned conveyance system comprising a guidance method having disturbance resistance.SOLUTION: In an unmanned conveyance system 500 having a pallet 200 comprising a base 210 and legs 220 and an unmanned carrier 100 comprising a lifter 140 lifting up and supporting the pallet 200, a travel device 120 and a control section 160 and causing the unmanned carrier 100 to travel to a prescribed position among the legs 220 of the pallet 200, an undersurface of the base 210 is provided with a bracket 230 protruding downward and extending so as to pass through a center line of the pallet 200. The unmanned carrier 100 comprises at least three laser sensors 150, and a control section 160 performing operation on the basis of data obtained from the laser sensors 150. A distance to the bracket 230 is detected by the laser sensors 150, an angle of the travel device 120 is adjusted on the basis of the data by the control section 160, and the unmanned carrier 100 is guided to an appropriate position.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a technique for guiding an automatic guided vehicle, and more particularly, to a technique for accurately guiding an automatic guided vehicle between legs of a pallet without depending on an installation position of a leg of the pallet.

  There are cases where an automated guided vehicle is used in a factory to move a pallet on which a large transported object is placed. However, there are cases in which the pallet is not accurately installed at a predetermined installation location. In such a case, in order to move the automatic guided vehicle between the pallet legs, it is necessary to correct the driving route. For this reason, an operator uses a controller such as a pendant switch to operate the automatic guided vehicle so that the automatic guided vehicle is properly placed between the pallet legs. Then, after the automatic guided vehicle is moved between the pallet legs, the pallet is lifted by the automatic guided vehicle and transported as it is.

  However, it is difficult to move the automatic guided vehicle between the legs of the pallet when the legs of the vertically long pallet are narrow and the approach angle of the automatic guided vehicle is large with respect to the pallet. For this reason, in addition to the operator who operates the controller of the automatic guided vehicle, a large number of supervisory workers are required, and an operation of carefully guiding the automatic guided vehicle is necessary. For this reason, a technique for solving this problem has been desired.

  Patent Document 1 discloses a technique related to an automatic guided vehicle and an automatic guided vehicle. The automated guided vehicle that has entered the lower side of the pallet from the entrance measures the distance to the derivative provided on the lower surface of the pallet base using the first and second laser sensors. Then, control is performed in the traveling direction so that the measured value matches the target value stored in the laser measurement memory. Here, since the derivative is continuously provided along the center line extending in the front-rear direction of the pedestal regardless of the installation state of the legs, the guided vehicle is guided regardless of the installation conditions of the legs. I can do it.

  Patent Document 2 discloses a technique related to a guided traveling method for an omnidirectional automatic guided vehicle. As a precondition, the automatic guided vehicle sets a target point that is a distance L away from the guidance sensor at the front of the vehicle body, and calculates the steering angle of the steered wheel by calculation based on the distance L and the guidance deviation detected by the guidance sensor. . At this time, the steering angle is corrected according to the condition of the distance L with respect to the induced deviation, thereby improving the straight traveling performance and convergence performance during straight traveling.

  Patent Document 3 discloses a technique related to a steering drive method and apparatus for an automatic guided vehicle. A steering drive wheel is provided at one diagonal position of the automatic guided vehicle, and a free caster is provided at the other diagonal position of the automatic guided vehicle. Then, when performing steering drive control of the steering drive wheels by the control device, the turning center point of the automatic guided vehicle is set on the X coordinate axis that is the center line in the vehicle width direction passing through the central point of the automatic guided vehicle. Further, based on the input steering angle of the front steering drive wheel and the speed at the center point, a control value for steering the steering drive wheel is calculated. In this way, the steering drive of the automatic guided vehicle during semi-automatic travel is controlled.

JP 2012-198756 A Japanese Patent No. 4089344 Japanese Patent No. 5407514

  However, it has been found that there is a problem in guiding the automatic guided vehicle even when the automatic guided system described in Patent Document 1 is used. Although the place where the automatic guided vehicle is moved is paved by being struck by concrete or the like in a factory, disturbances may occur due to rough floors or small obstacles. In such a case, the guidance of the automatic guided vehicle is not completed successfully, and troubles such as re-guidance occur.

  Patent Document 1 proposes a method of guiding the derivative provided along the center line extending in the front-rear direction of the pallet and the center line of the automatic guided vehicle, but for example, an automatic guided vehicle When the angle deviation from the bracket provided at the center of the pallet and the distance between the automatic guided vehicle and the bracket are obtained and the angle deviation and the distance are corrected to be small, the calculation methods as shown in Patent Document 2 and Patent Document 3 Can be considered. However, in any technique, the position of the turning center is limited and complicated calculation is required, so that there is a possibility that the automatic guided vehicle cannot be guided appropriately.

  Accordingly, an object of the present invention is to provide an unmanned conveyance system equipped with a guidance method that is resistant to disturbances in order to solve such problems.

  In order to achieve the above object, an unmanned conveyance system according to an aspect of the present invention has the following characteristics.

(1) A pallet comprising a platform for placing a conveyed product, and a leg that supports the platform, lifting means for lifting and supporting the pallet, a plurality of independently controllable traveling devices, An automatic guided vehicle comprising: a control unit that controls a traveling device; and the automatic guided vehicle travels the automatic guided vehicle to a position between the legs that can lift the pallet by the lifting unit. In the lower surface of the pedestal portion, a detected body that protrudes downward and extends so as to penetrate the center line of the pallet is provided, and the automatic guided vehicle is provided with at least three distance measuring means, Based on the data obtained from the distance measuring means, the control means detects the distance to the detected object by the distance measuring means, and the control means adjusts the steering angle of the traveling device based on the data. The unmanned Inducing Okukuruma in position, characterized by.

  According to the aspect described in the above (1), since the automatic guided vehicle is guided by including the three distance measuring means, it is possible to appropriately guide while suppressing the influence of the disturbance.

(2) In the unmanned conveyance system according to (1), the distance measuring unit uses a distance sensor that calculates a distance by emitting a specific wavelength and measuring a reflected wave thereof. The distance measuring means includes a first distance sensor, a second distance sensor, and a third distance sensor, wherein the first distance sensor is near the front end of the automatic guided vehicle, and the second distance sensor is the first distance sensor. The third distance sensor is arranged in the vicinity and in front of the center of the automatic guided vehicle, behind the center of the automatic guided vehicle and in front of the rear end, and the first distance sensor and the second distance sensor, or Using the data obtained from the first distance sensor and the third distance sensor, a turning center of the automatic guided vehicle is calculated by an arithmetic unit provided in the control means, and a turning radius that is a distance from the turning center is calculated. Calculating a steering angle of the serial traveling device, it is preferable.

  According to the aspect described in (2) above, the distance to the detected object attached to the pallet is detected using a distance sensor, and the rudder angle of the traveling device is determined according to the distance to control the automatic guided vehicle. It becomes possible. At this time, the first distance sensor is provided in the vicinity of the front end, and the second distance sensor is disposed behind the first distance sensor, in the vicinity of the first distance sensor, and in front of the center of the automatic guided vehicle. The third distance sensor is arranged behind the center of the automatic guided vehicle and ahead of the rear end. For this reason, the second distance sensor detects the position of the automatic guided vehicle at the initial stage of entry, and the third distance sensor can be used for position detection after the intermediate stage of the automatic guided vehicle to improve detection accuracy.

  Moreover, in order to achieve the said objective, the automatic guided system by another aspect of this invention has the following characteristics.

(3) A pallet including a platform portion on which a conveyed product is placed; a leg portion that supports the platform portion; lifting means that lifts and supports the pallet; a plurality of independently controllable traveling devices; An automatic guided vehicle comprising: a control unit that controls a traveling device; and the automatic guided vehicle travels the automatic guided vehicle to a position between the legs that can lift the pallet by the lifting unit. In which a virtual origin is defined on the center line of the automatic guided vehicle, and the travel position of the automatic guided vehicle is corrected so that the virtual origin is located immediately below the center line of the pallet.

  According to the aspect described in (3) above, the turning center can be determined by a relatively simple calculation of determining the virtual origin and determining the turning center. As a result, since there is no need to perform complicated calculation at high speed when guiding the automatic guided vehicle, highly accurate guidance can be realized at a relatively low cost.

It is a side view of the automatic guided system of this embodiment. It is a top view of the unmanned conveyance system of this embodiment. It is an AA arrow line view of FIG. 1 of the automatic guided system of this embodiment. It is a bottom view of the automatic guided vehicle of this embodiment. It is a flowchart regarding control of the unmanned conveyance system of this embodiment. It is explanatory drawing regarding the virtual point and distance used for the virtual origin position shift calculation of this embodiment. It is a graph which shows a mode that an automatic guided vehicle is guided with respect to the pallet of this embodiment. It is a graph regarding the measurement distance with the bracket by a distance sensor of this embodiment. It is a graph regarding the rudder angle of a travel axis of this embodiment. It is the graph regarding the rudder angle of the travel axis | shaft at the time of the disturbance in the prior art prepared for the comparison. It is a graph regarding the rudder angle of the traveling axis when a disturbance occurs in the present embodiment.

  First, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the side view of the unmanned conveyance system 500 of this embodiment is shown. FIG. 2 shows a top view of the automatic transport system 500. In FIG. 2, the lifter 140 is omitted. In FIG. 3, the AA arrow line view of the unmanned conveyance system 500 is shown. It corresponds to the AA arrow view of FIG. The automatic guided system 500 of this embodiment includes an automatic guided vehicle 100 and a pallet 200.

  The automatic guided vehicle 100 includes a vehicle body 110, a plurality of traveling devices 120, a plurality of lifters 140, and a plurality of laser sensors 150 that are distance measuring means. The vehicle body 110 is formed narrower in the traveling direction of the automatic guided vehicle 100. This shape matches the shape of the pallet 200.

  In FIG. 4, the bottom view of the automatic guided vehicle 100 is shown. The travel device 120 includes a first travel device 121, a second travel device 122, a third travel device 123, a fourth travel device 124, a fifth travel device 125, a sixth travel device 126, a seventh travel device 127, and an eighth travel. It consists of 10 traveling devices: a device 128, a ninth traveling device 129, and a tenth traveling device 130. Each traveling device 120 is disposed on the lower surface of the vehicle body 110 and has a rotation axis on the Z axis when the longitudinal direction of the vehicle body 110 is an X axis, and the angle can be arbitrarily changed. Moreover, each traveling device 120 includes two wheels, and the wheels are connected by an axle. At least some of the traveling devices 120 are drive wheels. In the present embodiment, the first traveling device 121, the second traveling device 122, the fifth traveling device 125, the sixth traveling device 126, the ninth traveling device 129, and the tenth traveling device 130 are drive wheels. In addition, the steering angle of each traveling device 120 can be arbitrarily controlled.

  The first traveling device 121 and the second traveling device 122 are arranged in front of the vehicle body 110 in the first row. The third traveling device 123 and the fourth traveling device 124 are arranged in a second row a little behind them, and the fifth traveling device 125 and the sixth traveling device 126 are the third row immediately behind the second row. Are arranged side by side. The seventh traveling device 127 and the eighth traveling device 128 are arranged in the fourth row with a little separation behind the third row, and the ninth traveling device 129 and the tenth traveling device 130 are located immediately behind the fourth row. Arranged side by side in the fifth column.

  The lifters 140 are provided at six locations on the upper surface of the vehicle body 110. The lifter 140 includes a hydraulic mechanism (not shown), and is lifted up and down in the height direction of the automatic guided vehicle 100 under the control of a control unit 160 and the like described later. The lifter 140 is used to lift the pallet 200 after the automatic guided vehicle 100 moves under the pallet 200 and the upper surface of the lifter 140 comes into contact with the lower surface of the pallet 200 to push it up. In addition, the vehicle body 110 includes a control unit 160 including an arithmetic device, and an operation pendant (not shown) is connected to the control unit 160 via a wire. The automatic guided vehicle 100 can be guided by the operation pendant.

  As shown in FIG. 4, two laser sensors 150 are provided in three rows, and a total of six laser sensors 150 are attached to the upper surface of the vehicle body 110. As shown in FIG. 3, the laser sensor 150 detects the bracket 230 provided at the lower center of the base 210 of the pallet 200 when at least a part of the automatic guided vehicle 100 enters the lower side of the pallet 200. It is fixed to the vehicle body 110 so that the light L is emitted at a constant angle.

  The laser sensor 150 includes six sensors: a first sensor 151, a second sensor 152, a third sensor 153, a fourth sensor 154, a fifth sensor 155, and a sixth sensor 156. The first sensor 151 corresponding to the first distance sensor and the second sensor 152 make a pair, the third sensor 153 corresponding to the second distance sensor and the fourth sensor 154 make a pair, and the third distance sensor The corresponding fifth sensor 155 and sixth sensor 156 are used in pairs.

  The first sensor 151 and the second sensor 152 are attached to the left and right near the front end of the vehicle body 110, that is, on the first line L1. The third sensor 153 and the fourth sensor 154 are arranged on the left and right sides of the forward side of the vehicle body 110 and at the same position as the first row of the traveling device 120 as viewed from above the vehicle body 110, that is, aligned on the second line L2. ing. The fifth sensor 155 and the sixth sensor 156 are arranged on the left and right sides, that is, on the third line L3, side by side behind the center of the vehicle body 110 and behind the third row of the traveling device 120.

  Therefore, it can be said that the first line L1, the second line L2, and the third line L3 are lines through which the optical axis of the laser sensor 150 passes. That is, the laser beam L overlaps on this line. Each sensor is arranged so that the distance from the center in the width direction (center line CL) of the vehicle body 110 is equal.

  As shown in FIG. 1, the pallet 200 includes a base 210 formed of a substantially trapezoidal plate material, leg portions 220 fixedly provided so as to protrude below the base 210, and a bracket 230 on the lower surface of the base 210. Provided. A work 280 is placed on the upper surface of the base 210. A bracket 230 is attached to the lower surface of the base 210 so as to penetrate the centers of the upper and lower sides of the trapezoid. The bracket 230 is preferably made of a metal member that reflects the laser emitted from the laser sensor 150 well and protrudes at a uniform height in the longitudinal direction of the base 210. Note that the material of the bracket 230 is not limited to metal, and any material can be used as long as it reflects the laser well.

  The leg portion 220 is provided so as to protrude below the base 210. The leg part 220 has a function of supporting the base 210 on which the work 280 is placed. A total of ten leg portions 220 are provided along the hypotenuse portion of the base 210, but the number of the leg portions 220 is not particularly limited.

  Next, control of the automatic transport system 500 will be described. FIG. 5 shows a flowchart relating to control of the automatic transport system 500. The contents are roughly described below.

  First, the measurement result of the laser sensor 150 is acquired in S10. The measurement data of the six laser sensors 150 described above is passed to the control unit 160 as a read value. In S11, it is determined whether or not the read value in the first line L1 satisfies the “condition”. As described above, the first sensor 151 and the second sensor 152 are arranged in the first line L1, and if the read values of the first sensor 151 and the second sensor 152 satisfy the “condition”, the process proceeds to S12. If the “condition” is not satisfied, the process proceeds to S21.

  Specifically, the “condition” is to check whether the reading values of the first sensor 151 and the second sensor 152 are abnormal, or whether the change in the reading value of the first sensor 151 or the second sensor 152 is 20 mm or less, Alternatively, it is checked whether the reading value of the first sensor 151 or the second sensor 152 is 1 m or more. The change in the reading value of the first sensor 151 or the second sensor 152 is related to the scan timing of the laser sensor 150 and the speed of the automatic guided vehicle 100, but in this embodiment, the change of the automatic guided vehicle 100 exceeds 20 mm. Therefore, it is determined as abnormal.

  In the present embodiment, the distance from the first sensor 151 or the second sensor 152 to the center of the automatic guided vehicle 100 is 2 m, and when the position of the bracket 230 is 1 m or more away from the center of the automatic guided vehicle 100, the automatic guided vehicle 100 is in contact with the pallet 200, that is, it is determined as abnormal.

  In S12, the first position data LZS1 is acquired. Here, the first position data LZS1 is defined as the distance from the center of the vehicle body 110 to the bracket 230 in the first line L1, and the first sensor 151 and the second sensor 152 arranged in the first line L1. Calculate from at least one of the readings.

  In S13, it is determined whether the read value in the third line L3 satisfies the “condition”. As described above, the fifth sensor 155 and the sixth sensor 156 are arranged in the third line L3. The “condition” here is also set in the same manner as in S11. If the reading values of the fifth sensor 155 and the sixth sensor 156 satisfy the condition, the process proceeds to S14, and if the condition does not satisfy the condition, the process proceeds to S16.

  If the reading values of the fifth sensor 155 and the sixth sensor 156 satisfy the condition, the third position data LZS3 is acquired in S14. Here, the third position data LZS3 is defined as the distance from the center of the vehicle body 110 to the bracket 230 on the third line L3, and is read by the fifth sensor 155 and the sixth sensor 156 arranged on the third line L3. Calculate from at least one of the values.

数式１に用いられるＬＺＳｎは、第１ポジションデータＬＺＳ１、第２ポジションデータＬＺＳ２、第３ポジションデータＬＺＳ３の何れかである。また、Ｌ_ｓ１は車体１１０の先端から第１ラインＬ１までの距離であり、Ｌ_ｓ２は車体１１０の先端から第２ラインＬ２までの距離である。θ_ｎは仮想原点ＶＰｎと旋回中心ＡＲを結ぶ直線と、旋回中心ＡＲから車体１１０の幅方向の中心線ＣＬに引いた垂線がなす角である。図６に、仮想原点位置ずれ計算に用いた仮想点と距離に関する説明図を示す。 In S15, the turning center AR is calculated from the first position data LZS1 and the third position data LZS3.

LZSn used in Equation 1 is any one of the first position data LZS1, the second position data LZS2, and the third position data LZS3. Further, L _s 1 is a distance from the front end of the vehicle body 110 to the first line L1, and L _s 2 is a distance from the front end of the vehicle body 110 to the second line L2. θ _n is an angle formed by a straight line connecting the virtual origin VPn and the turning center AR and a perpendicular drawn from the turning center AR to the center line CL in the width direction of the vehicle body 110. FIG. 6 is an explanatory diagram regarding virtual points and distances used for calculating the virtual origin position deviation.

A first angle θ ₁ formed by a straight line connecting the first virtual origin VP1 and the turning center AR and a perpendicular PL drawn to the turning center AR and the center line CL in the width direction of the vehicle body 110 is the first virtual origin VP1 and the turning center AR. Is equal to the angle formed by the straight line intersecting the straight line passing through the first virtual origin VP1 and the center line CL. This holds true for the first triangle A ₁ and the second triangle A ₂ is in a similar relationship. The first triangle A ₁ whose vertices pivot AR shown in FIG. 6, since the first virtual home VP1 say that it second triangle A ₂ and similar relation to the apex, each of the angles equal.

The third angle θ ₃ formed by the perpendicular line PL and the straight line connecting the turning center AR and the third virtual origin VP3 is a straight line intersecting the turning center AR and the straight line passing through the third virtual origin VP3 and the center line CL. Is the same as the angle formed by. This holds for the third triangle B ₁ and the fourth triangle B ₂ are in similar relationship. Since it can be said the turning center AR shown in FIG. 6 and the third triangle B ₁ whose vertices third virtual origin VP3 and fourth triangle B ₂ whose apexes and similar relationships, each of the angles are equal. Equation 1 uses this relationship to determine θ _n .

次に、数式２を用いて中心線ＣＬから旋回中心ＡＲまでの距離Ａを算出する。数式２も、旋回中心ＡＲを頂点とする第１三角形Ａ_１は第１仮想原点ＶＰ１を頂点とする第２三角形Ａ_２と、旋回中心ＡＲを頂点とする第３三角形Ｂ_１は第３仮想原点ＶＰ３を頂点とする第４三角形Ｂ_２と、それぞれ相似関係にある為、これを利用して距離Ａを算出できる。なお、数式２の場合は、中心線ＣＬに対して左側に第２三角形Ａ_２が位置し、中心線ＣＬに対して右側に第４三角形Ｂ_２が位置しているので、数式２で距離Ａを求められるが、この位置関係によっては符合を変化させる必要がある。

Next, a distance A from the center line CL to the turning center AR is calculated using Formula 2. In Equation 2, the first triangle A ₁ having the turning center AR as the vertex is the second triangle A ₂ having the first virtual origin VP1 as the vertex, and the third triangle B ₁ having the turning center AR as the vertex is the third virtual origin. a fourth triangle B ₂ whose vertices VP3, since in the similar relationship each can calculate the distance a by using this. In the case of Equation 2, the second triangle A ₂ is located on the left side with respect to the center line CL, and the fourth triangle B ₂ is located on the right side with respect to the center line CL. However, depending on the positional relationship, it is necessary to change the sign.

そして、数式３を用いて、旋回中心ＡＲから第１走行装置１２１または第２走行装置１２２までの車体１１０の長手方向の距離、すなわち垂線ＰＬから第２ラインＬ２までの第１距離ＦＢを求める。こうして距離Ａと第１距離ＦＢより旋回中心ＡＲが算出される。

Then, using Formula 3, a longitudinal distance of the vehicle body 110 from the turning center AR to the first traveling device 121 or the second traveling device 122, that is, a first distance FB from the perpendicular PL to the second line L2 is obtained. Thus, the turning center AR is calculated from the distance A and the first distance FB.

また、数式４を用いて、旋回中心ＡＲから第９走行装置１２９又は第１０走行装置１３０までの車体１１０の長手方向の第２距離ＲＢを算出できる。ここで、距離ＷＢは第１走行装置と第２走行装置の配置されている第１列から第９走行装置と第１０走行装置の配置される第５列までの距離を示している。

Further, the second distance RB in the longitudinal direction of the vehicle body 110 from the turning center AR to the ninth traveling device 129 or the tenth traveling device 130 can be calculated using Formula 4. Here, the distance WB indicates the distance from the first row where the first traveling device and the second traveling device are arranged to the fifth row where the ninth traveling device and the tenth traveling device are arranged.

  If the reading value of the sixth sensor 156 does not satisfy the condition in the fifth sensor 155, it is determined in S16 whether the reading value in the second line L2 satisfies the “condition”. As described above, the third sensor 153 and the fourth sensor 154 are arranged in the second line L2. The “condition” here is set in the same manner as in S11. If the read values of the third sensor 153 and the fourth sensor 154 satisfy the “condition”, the process proceeds to S17, and if the read value does not satisfy the “condition”, the process proceeds to S21.

  In S17, second position data LZS2 is acquired. Here, the second position data LZS2 is defined as a distance from the center of the vehicle body to the bracket 230 in the second line L2, and reading values of the third sensor 153 and the fourth sensor 154 arranged in the second line L2. It calculates from at least one of these.

Ｓ１９にて、各走行装置の舵角δ_ｎと速度Ｖ_ｎを算出する。Ｓ１５又はＳ１８で旋回中心ＡＲを算出した後、第１走行装置１２１乃至第１０走行装置１３０の各軸の舵角δ_ｎを、三角関数を用いて算出する。 In S18, the turning center AR is calculated from the first position data LZS1 and the second position data LZS2. Calculation of the turning center AR uses Formula 1, Formula 3, Formula 4, and Formula 5 below.

In S19, the steering angle δ _n and the speed V _n of each traveling device are calculated. After calculating the turning center AR in S15 or S18, the steering angle δ _n of each axis of the first traveling device 121 to the tenth traveling device 130 is calculated using a trigonometric function.

数式６に用いられるＶは、ユーザーが任意に定める。またＲ_ｍａｘはＲｎの最大値を用いている。この数式６によって、走行装置１２０である、第１走行装置１２１、第２走行装置１２２、第５走行装置１２５、第６走行装置１２６、第９走行装置１２９、及び第１０走行装置１３０の各軸の速度が決定される。そしてＳ２０にて算出した舵角δ_ｎと速度Ｖ_ｎの通り、各走行装置を制御する。 Also, the turning radius R _{n of} each axis can be calculated using the steering angle δ _n and the three-square theorem. In either case, mathematical expressions are omitted. The speed V _n can be calculated using the following equation.

V used in Equation 6 is arbitrarily determined by the user. R _max is the maximum value of Rn. According to Equation 6, each axis of the first traveling device 121, the second traveling device 122, the fifth traveling device 125, the sixth traveling device 126, the ninth traveling device 129, and the tenth traveling device 130, which is the traveling device 120. The speed is determined. Then, each traveling device is controlled according to the steering angle δ _n and the speed V _n calculated in S20.

  In the automatic guided system 500 of the present embodiment, the automatic guided vehicle 100 is guided under the pallet 200 in the above flow.

  As a concept, two arbitrary points on the center line CL of the vehicle body 110 of the automatic guided vehicle 100 are set as the virtual origin. In the present embodiment, the vehicle body 110 is provided by guiding the automatic guided vehicle 100 so that the first virtual origin VP1 and the third virtual origin VP3 are overlapped with the bracket 230 so that the first virtual origin VP1 and the third virtual origin VP3 overlap each other. It is possible to move to the position.

  Then, if the traveling direction of the virtual origin is the tangential direction of the turning locus of the virtual origin, the turning center exists on the perpendicular drawn from the virtual origin. Therefore, the point at which the turning centers of the first virtual origin VP1 and the third virtual origin VP3, which are the two virtual origins, coincide with each other, and the turning center AR of the automatic guided vehicle 100 can be determined. In the present embodiment, since an example using the first position data LZS1 and the third position data LZS3 is shown, the first virtual origin VP1 and the third virtual origin VP are used as the virtual origin. Therefore, when using the second position data LZS2, the second virtual origin VP2 is set.

  Since the unmanned conveyance system 500 of the present embodiment has the configuration described above, the following effects and operations are achieved. First, since the automatic guided system 500 in this embodiment is provided, it is possible to provide a guidance method that is strong against disturbance of the automatic guided vehicle 100.

  This is because the unmanned conveyance system 500 of the present embodiment includes a pallet 200 that includes a base 210 on which the workpiece 280 is placed and a leg portion 220 that supports the base 210, a lifter 140 that lifts and supports the pallet 200, and a plurality of lifters 140. An automatic guided vehicle 100 including a traveling device 120 that can be independently controlled, and the automatic guided vehicle 100 travels to a position between legs 220 that can lift the pallet 200 by a lifter 140. A bracket 230 is provided on the lower surface of the base 210 so as to protrude downward and extend through the center line of the pallet 200. The automatic guided vehicle 100 includes at least three laser sensors 150 and the laser sensor 150. A controller 160 for operating based on the received data, and a laser sensor 150 Detecting the distance to the bracket 230 to adjust the angle of the traveling device 120 based on the data by the control unit 160, is because those which induce AGV 100 in position.

FIG. 7 is a graph showing how the automatic guided vehicle 100 is automatically guided with respect to the pallet 200. The state of the movement of the automatic guided vehicle 100 is overwritten every 5 seconds, and the center of the automatic guided vehicle 100 is shifted from the center of the pallet 200 by a deviation angle θ ₀ at the initial position in FIG. From this state, the state where the automatic guided vehicle 100 is automatically guided and fits under the pallet 200 is shown. In FIG. 8, the graph regarding the measurement distance with the bracket by a distance sensor is shown. The vertical axis represents the position (m) of the laser sensor 150, and the horizontal axis represents the elapsed time (seconds). In FIG. 9, the graph regarding the steering angle of a traveling apparatus is shown. The vertical axis represents the angle (deg), and the horizontal axis represents the elapsed time (seconds).

  The laser sensor 150 attached to the vehicle body 110 includes a first sensor 151 and a second sensor 152 provided on the first line L1, and a third sensor 153 and a fourth sensor 154 provided on the second line L2. Alternatively, the first sensor 151 and the second sensor 152 provided on the first line L1 and the fifth sensor 155 and the sixth sensor 156 provided on the third line L3 are used as a set. Is done. As shown in FIG. 4, the first line L1 is provided at the front end of the vehicle body 110, but may be disposed slightly behind the front end from the viewpoint of sensor protection. However, since the first sensor 151 and the second sensor 152 arranged in the first line L1 have a function of detecting the vehicle body 110 when it enters the pallet 200, the first sensor 151 and the second sensor 152 are arranged as close to the tip of the vehicle body 110 as possible. It is desirable.

  As described above, the second line L <b> 2 is provided in the first row of the traveling devices, that is, around the first traveling device 121 and the second traveling device 122. Since this position should be closer to the first line, it is preferable that the position be located near the tip of the vehicle body 110 and in front of the center of the vehicle body 110 at a level that does not hinder the angle detection. This is due to the desire to detect the position of the vehicle body 110 using the sensor 150 as early as possible. With the configuration of the present embodiment, guidance can be started from a position where both the first line L1 and the second line L2 intersect the bracket 230.

  On the other hand, since the third line L3 is provided behind the fifth traveling device 125 and the sixth traveling device 126 and behind the center of the vehicle body 110, the third line L3 moves to a position where it intersects the bracket 230. After that, it can be used for guiding the automatic guided vehicle 100. The result is the range of use of the second position data LZS2 and the range of use of the third position data LZS3 shown in FIG. The setting of the third line L3 is preferably a position as far as possible from the top of the vehicle body 110 in consideration of correction of the vehicle body 110. However, if the vehicle is placed too far behind the vehicle body 110, most of the vehicle body 110 is placed on the pallet 200. The section that can be used for guidance is shortened because it falls below. For this reason, in the present embodiment, the third line L3 is disposed so as to be located slightly rearward from the center of the vehicle body 110.

The inclination of the vehicle body 110 can be detected more preferentially by the fifth sensor 155 and the sixth sensor 156 that are further away from the first sensor 151 and the second sensor 152. This is because the laser sensor 150 detects the distance, and therefore the difference tends to increase greatly when the distance from the head of the automatic guided vehicle 100 is increased. And the graph regarding the steering angle of each axis | shaft shown in FIG. 9 also shows the same tendency. It can be seen that the rudder angle δ _{n of} each axis also converges to an angle of 0 over time. That is, it can be said that the third position data LZS3 is more advantageous for detection than the second position data LZS2. As a result, it is advantageous for guiding the automatic guided vehicle 100.

  Next, the situation when a disturbance is applied to the automatic guided vehicle 100 will be described. The disturbance may occur when the road surface on which the automatic guided vehicle 100 passes is uneven or noise is generated in the laser sensor 150, and is a situation assumed in actual operation. In FIG. 10, the graph regarding the steering angle of the traveling apparatus 120 when the disturbance prepared for the comparison in a prior art generate | occur | produces is shown. FIG. 10 shows a case where the sensors provided in the third line L3, that is, the fifth sensor 155 and the sixth sensor 156 are not used. In FIG. 11, the graph regarding the steering angle of the traveling apparatus 120 when the disturbance generate | occur | produces of this embodiment is shown. FIG. 10 and FIG. 11 both show the situation when a disturbance is applied 50 seconds after the start of guidance. All were compared by applying disturbance under the same conditions.

  As can be seen from the comparison, when the sensors provided for the third line L3, that is, the fifth sensor 155 and the sixth sensor 156 are not used, it can be seen that the steering angle of each axis is greatly disturbed. According to the example, the position can be corrected without being greatly disturbed. That is, even when a disturbance occurs, the position can be quickly corrected with the automatic guided vehicle 100 according to the present embodiment.

  The first position data LZS1 to the third position data LZS3 use two laser sensors 150 each. Any of these may be used for distance measurement, but it is desirable to complement the data with each other. By doing so, it is possible to cope with a disturbance. As a result, it is possible to accurately grasp the position of the vehicle body 110 and contribute to accurate guidance of the automatic guided vehicle 100. Of course, when no disturbance occurs, unmanned conveyance using only the third sensor 153 and the fourth sensor 154 of the second line L2, or the fifth sensor 155 and the sixth sensor 156 of the third line L3. The car 100 can be guided.

  In addition, as an unmanned transport system, an unmanned transport system such as that shown in Patent Document 1 has been devised in the past. However, in the actual site, the automatic guided vehicle has not been guided because it does not meet the cost.

  However, in the present embodiment, a pallet including a pedestal portion on which a conveyed product is placed, a leg portion that supports the pedestal portion, lifting means that lifts and supports the pallet, and a plurality of independently controllable traveling devices. And a control means for controlling the traveling device, and the automatic guided vehicle travels to a position between the leg portions where the pallet can be lifted by the lifting means. In the automatic guided system, a virtual origin is defined on the center line of the automatic guided vehicle, and the traveling position of the automatic guided vehicle is corrected so that the virtual origin is located immediately below the center line of the pallet. It proposes an automated transport system.

  That is, the pallet 200 including the base 210 on which the work 280 is placed, the leg portion 220 that supports the base 210, the lifter 140 that lifts and supports the pallet 200, and a plurality of independently controllable traveling devices 120 are provided. In the unmanned transport system 500 that includes the transport vehicle 100 and travels the unmanned transport vehicle 100 to a position between the leg portions 220 where the pallet 200 can be lifted by the lifter 140, a virtual origin is set on the center line of the unmanned transport vehicle 100. And the traveling position of the automatic guided vehicle 100 is corrected so that the virtual origin is located immediately below the center line of the pallet 200.

As a result, for example, the first virtual origin VP1 and the third virtual origin VP3, which are the virtual origins shown in FIG. 6, are determined as two arbitrary points on the center line CL of the vehicle body 110, and based on this, the first triangle A ₁ and the second triangle _{a 2} and the third triangle _{B 1} and the fourth triangle _{B 2} is set. Then, using the similarity of these triangles, the turning center AR is obtained. Then, the automatic guided vehicle 100 is moved to a predetermined position under the pallet 200 by determining and moving the rudder angle δ of each axis so as to realize the required turning center AR and turning radius. It is possible to guide to the position.

  As mentioned above, although embodiment of the automatic guided system 500 concerning this invention was described, this invention is not necessarily limited to this, A various change is possible in the range which does not deviate from the meaning. For example, the shape of the vehicle body 110 of the automatic guided vehicle 100 shown in the present embodiment has a substantially trapezoidal shape. However, the shape is not limited to this shape, and for example, a shape as in Patent Document 1 can be applied. is there. Further, the shape of the pallet 200 is not limited to this. Further, in the present embodiment, there are six driving wheels of the traveling device 120, but it is not hindered to increase or decrease these.

  In this embodiment, the virtual origin is calculated as the first virtual origin VP1 and the third virtual origin VP3. However, as described above, the virtual origin can also be calculated using the second virtual origin. As described above, the virtual origin may be any two points on the center line CL of the vehicle body 110 of the automatic guided vehicle 100 as the virtual origin, and by using other than the first virtual origin VP1 to the third virtual origin VP3, The automatic guided vehicle 100 can be guided.

  In addition, in the present embodiment, the first virtual origin VP1 is determined at the intersection of the second line L2 and the center line CL of the automatic guided vehicle 100, the distance from the second virtual origin VP2 to the second line L2, and the third The virtual origin is determined so that the distance from the virtual origin VP3 to the third line L3 is equal to the distance from the first virtual origin VP1 to the first line L1, but the position of the virtual origin is not limited to this. Absent. Even in this case, if the traveling direction of the virtual origin is the tangential direction of the turning locus of the virtual origin, the automatic guided vehicle 100 is guided by setting so that the turning center exists on the perpendicular drawn from the virtual origin.

100 automatic guided vehicle 110 vehicle body 120 traveling device 140 lifter 150 laser sensor 200 pallet 210 base 220 leg 230 bracket 280 work 500 automatic guided system

Claims (3)

A pallet comprising a platform on which the object is placed and a leg that supports the platform;
A lifting means for lifting and supporting the pallet, a plurality of independently controllable traveling devices, and a control means for controlling the traveling device, and an automatic guided vehicle,
In the unmanned transport system that travels the automatic guided vehicle to a position between the legs that can lift the pallet by the lifting means,
On the lower surface of the pedestal portion, a detected object is provided that protrudes downward and extends through the center line of the pallet,
The automatic guided vehicle is provided with at least three distance measuring means, and the distance to the detected object is detected by the distance measuring means by the control means based on data obtained from the distance measuring means, Adjusting the steering angle of the traveling device based on the data by the control means, and guiding the automatic guided vehicle to an appropriate position;
Unmanned transport system. In the unmanned conveyance system of Claim 1,
The distance measuring means uses a distance sensor that calculates a distance by emitting a specific wavelength and measuring a reflected wave thereof,
The three distance measuring means comprise a first distance sensor, a second distance sensor, and a third distance sensor,
The first distance sensor is in the vicinity of the front end of the automatic guided vehicle, the second distance sensor is in the vicinity of the first distance sensor and before the center of the automatic guided vehicle, and the third distance sensor is in the automatic guided vehicle. Located behind the center of the car and ahead of the rear end,
Using the data obtained from the first distance sensor and the second distance sensor, or the first distance sensor and the third distance sensor, the turning center of the automatic guided vehicle is calculated by an arithmetic unit provided in the control means. And calculating the steering angle of the traveling device from a turning radius that is a distance from the turning center,
Unmanned transport system. A pallet comprising a platform on which the object is placed and a leg that supports the platform;
A lifting means for lifting and supporting the pallet, a plurality of independently controllable traveling devices, and a control means for controlling the traveling device, and an automatic guided vehicle,
In the unmanned transport system that travels the automatic guided vehicle to a position between the legs that can lift the pallet by the lifting means,
A virtual origin is defined on the center line of the automatic guided vehicle, and the travel position of the automatic guided vehicle is corrected so that the virtual origin is located immediately below the center line of the pallet;
Unmanned transport system.

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