JPH09301680A - Overhead traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control lowering of a hand without accurate teaching or any guide poles by providing a workpiece detection sensor for detecting the position of a workpiece and a hand control means for stopping lowering of the hand based on a workpiece detecting signal in the hand. SOLUTION: When a hand 12 is brought close to a target position and loading is carried out, a workpiece is detected by a workpiece detection sensor in the vicinity of a centering member 120 positioned close to the holding plate 010 of a workpiece upper end. Chucking is not allowed in this position, lowering of the hand 12 is continued, a lowering distance during this time is read by an encoder and the movement of the hand 12 is stopped when it is lowered by a specified length after the detection of the workpiece. Then, a chuck 126 is rotated, the workpiece is held and the hand 12 is experimentally raised by a specified length. Then, when the workpiece detection sensor is changed from a closed state (workpiece detected) to an open state (workpiece not detected), the hand 12 is raised understanding that loading is stably carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead traveling vehicle for holding and transporting a work by a hand, and more particularly, to lowering control of the hand.

[0002]

2. Description of the Related Art Overhead traveling vehicles are used to convey goods and products (work) in factories and warehouses. The overhead traveling vehicle travels while being supported by, for example, rails laid along the ceiling of the building, and the hoisting unit provided in the main body moves the hand up and down. A guide pole provided on the ground station is used for lowering the hand, and when the pole detection sensor provided on the hand detects the guide pole, the hand is stopped and the works to be conveyed are loaded or unloaded.

However, when the guide pole is used, the position where loading and unloading can be performed is limited to a predetermined position. If you do not use a guide pole here, how much the hand should descend for loading and unloading,
It is necessary to teach in advance. Teaching is learning the descending position of the hand, and loading and unloading cannot be done without teaching correctly. Therefore, teaching needs to be performed accurately, which requires a lot of time and labor.

[0004]

An object of the present invention is to 1) enable a hand descending control without accurate teaching and without using a guide pole (claims 1 to 3), and 2) workpiece detection sensor. Then, the lowering control of the hand and the two detections that the work is stably held are performed (Claim 3).

[0005]

According to the present invention, there is provided a main body supported by a traveling rail for traveling, a hoisting unit provided at a lower portion of the main body, and a hand provided with a chuck for raising and lowering by the hoisting unit and holding a work. In the overhead traveling vehicle provided, a work detection sensor for detecting the work position is provided in the hand, and a hand control means for stopping the lowering of the hand based on a work detection signal from the work detection sensor. It is characterized by being provided.

A position sensor such as a photoelectric sensor, an infrared sensor, or an ultrasonic sensor is used as the workpiece detection sensor.
Light, infrared rays, ultrasonic waves, or the like that reach the light receiving portion or the receiving portion without being reflected by the work may be used, or light, infrared rays, ultrasonic waves, or the like reflected or scattered by the work may be used. Although the hand may be stopped immediately after the work is detected by the work detection sensor, the hand may be lowered for a predetermined time or a predetermined distance before actually stopping the hand. This time and distance depend on the positional relationship between the workpiece detection sensor and the chuck.For example, when the workpiece detection sensor is above the chuck, the workpiece detection sensor detects the upper end of the workpiece and the like, and then the workpiece is not held by the chuck. You just have to lower the distance until it becomes possible.

[0007] Preferably, the hand control means is configured to further lower the hand for a predetermined length to stop the lowering of the hand after the work is detected by the work detection sensor. That is, the shape of the work is known for the overhead traveling vehicle by teaching or the like, and it is already known how much the work can be chucked if the descent is continued after the work is detected. Therefore, if the distance between them is controlled by open loop, or in the case of the embodiment, the rotation speed of the hoisting motor for lowering the hand is read by an encoder and lowered, the hand can be stopped at a chuckable position.

Further, preferably, the work detection sensor is provided above the chuck at a position where the work is not detected when the work is held stably and the work is detected when the work becomes unstable. Preferably, a plurality of work detecting sensors are provided to detect the presence or absence of inclination of the work and to adopt a majority logic or the like to eliminate a detection error.

[0009]

According to the present invention, the position of the work with respect to the hand is detected by the work detecting sensor. Taking loading as an example, a work detection sensor detects a work, and if necessary, the work is further lowered for a predetermined length to stop the hand. In the case of unloading, when the work lands on the ground, the work floats from the chuck, and this is detected by the work detection sensor to stop the hand. Since the chuck is usually fitted in the groove or hole of the work, it is often not possible to chuck immediately after the work lands.In such a case, as in the case of loading, the specified length is required. Further descend and chuck. Therefore, no guide pole is required, and teaching before loading and unloading is also unnecessary or simplified (Claim 1).

According to the second aspect of the present invention, after the work is detected by the work detection sensor, the hand is lowered by a predetermined length by open loop control or by monitoring the rotation speed of the hoisting motor by the encoder. For this reason, the hand can be accurately lowered to a position where it can be chucked accurately in both loading and unloading.

According to the third aspect of the present invention, the work detection sensor is used both for controlling the lowering of the hand and for detecting whether or not the work is held stably. The sensor does not detect the work when the chuck fits in the groove or hole provided in the work and holds it stably. If the holding becomes unstable and the work floats from the chuck, the sensor detects the work. For this reason, the work detection sensor can be used both for lowering the hand and for detecting the holding state of the work.

[0012]

1 to 17 show an overhead traveling vehicle according to an embodiment.
First, the overall structure of the overhead traveling vehicle and the structure of the bogie will be described. FIG.
Shows the overall structure of the overhead traveling vehicle 2, 01 is a rail laid along the ceiling of a building such as a clean room or a factory,
Reference numeral 02 denotes a rail, and reference numeral 03 denotes a communication cable between the overhead traveling vehicle 2 and the management center. The overhead traveling vehicle 2 has two trolleys 4,
4, and each truck 4 includes a bumper 6. The main body 8 is connected to the carts 4 and 4 by a pivot shaft 32 shown in FIGS. 2 to 4, and a hoisting unit 10 is provided below the main body 8. Then, the hoisting unit 10 raises and lowers the hand 12, and the hand 12 holds and transports a work 04 such as a SMIF pod containing a semiconductor substrate. Reference numerals 14 and 14 denote a pair of fall prevention members for preventing the work 04 from dropping when the hand 12 is lifted and the work 04 is transported.

[0013]

[Dolly] FIG. 2 shows the structure of the trolleys 4 and 4 viewed from a direction perpendicular to the traveling direction of the overhead traveling vehicle 2, FIG. 3 shows the structure of the trolleys 4 and 4 viewed from the ceiling side, and FIG. The section of the carriage 4 in a direction perpendicular to 01 is shown. In these figures, the covers and the like of the carts 4 and 4 are removed. Referring to FIG. 4 to illustrate the mounting of the trolleys 4 and 4 on the rail 01, 05
Is a support for the rail 01, which has a function of adjusting the height of the rail 01, and is covered with a cover 06. Reference numeral 08 denotes an overhead line for supplying power to the overhead traveling vehicle 2, and reference numeral 09 denotes a mark for transmitting a stop position and the like to the overhead traveling vehicle 2.

As shown in FIGS. 2 to 4, traveling motors 16 and 17 are provided for each carriage 4 substantially horizontally along the longitudinal direction of the carriage 4 (direction parallel to the rails 01). The motor shaft 20 is substantially horizontal, for example, in a range of ± 10 degrees with respect to a horizontal plane. A brake is not provided for the traveling motors 16 and 17, and a brake 18 such as an electromagnetic brake is provided separately. The motor shaft 20 and the brake shaft 22 of the brake 18 are connected to the hypoid gear 24, the rotation direction is changed by 90 degrees, the traveling shaft 25 is rotated, and the traveling wheels 26 are driven. Here, the running wheel 26 has a vertical rotating surface, but may be horizontal. Two
Reference numeral 8 denotes a guide roller for preventing each truck 4 from coming off the rail 01. For example, eight guide rollers are provided for each truck 4 as shown in FIGS. Guide rollers 28, 28 are also provided at the tip of the bumper 6, and the bumper 6 is
To make it run smoothly. Reference numeral 30 denotes a current collector rotatable about a vertical axis, which receives power from the overhead wire 08 and
Power is supplied to 6, 17 and so on.

Numerals 32, 32 are pivot shafts for connecting the carts 4, 4 to the main body 8. As a result, the pair of carts 4 and 4 act as bogies with respect to the main body 8. 34, 34
Is a pivot shaft connecting the bumpers 6, 6 to the carts 4, 4, and is connected to the covers 15, 15 of the carts 4, 4. The bumper 6 travels on the rail portion 02 by the guide roller 28, and can be turned with respect to the carriage 4 by the pivot shaft 34. Proximity sensor 3 at the tip of bumpers 6 and 6
6 is provided to detect a preceding traveling vehicle, an obstacle, and the like. Reference numeral 38 denotes a reading sensor provided to face the mark 09.
The stop position and the like are detected by assisting the control data built in the main body 8.

The features of the carts 4 and 4 will be described. It is important that the overhead traveling vehicle 2 used in a crane room or the like has a small volume. In the case of the truck 4, since the space along the longitudinal direction of the rail 01 is allocated to the overhead traveling vehicle 2, it is important to reduce the width and height of the truck 4, 4 with respect to the rail 01. In the embodiment, the traveling wheels 26 are located near the center of the carriage 4 along the longitudinal direction, the traveling motors 16 and 17 are on one side, and the brakes 18 are on the other side.
There is. The traveling motors 16 and 17 are partially
Sticking out from. The motor shaft 20 and the brake shaft 22 are substantially horizontal, for example, in a range of ± 10 degrees with respect to a horizontal plane, and their directions are parallel to the traveling direction of the carriage 4. Therefore, the longitudinal directions of the motors 16 and 17 and the brake 18 are parallel to the longitudinal direction of the rail 01, and the height and width of the carts 4 and 4 are reduced. The motor shaft 20 and the brake shaft 22 are connected to the hypoid gear 24, and drive the traveling wheels 26 by changing the direction of the rotating shaft to a right angle. In the hypoid gear 24, its axial direction does not intersect with the axial directions of the motor shaft 20 and the brake shaft 22. For example, in FIG.
Are simply arranged in parallel without overlapping. When the hypoid gear 24 is used, power can be transmitted more reliably with a thinner gear than a bevel gear, and therefore, the thickness of the gear portion can be reduced, and the height of the carts 4 can be reduced.

The traveling motors 16, 17 and the brake 18 are separately provided, and are disposed so as to be substantially opposed to each other around the traveling wheel 26. Since the motors 16 and 17 and the brake 18 are separated from each other, the motor can be miniaturized, and the load on them can be reduced by the traveling wheel 2.
6 are dispersed on both sides and become stable. If the brake 18 is integrated with the traveling motors 16 and 17, the size of the motor becomes large, and the traveling wheels 26 must be arranged substantially at the center of the truck 4, so that the truck 4 becomes large. Further, the load is concentrated on one side of the carriage 4 and becomes unstable.

Next, the two carts 4 and 4 are separated from the main body 8 and connected by pivot shafts 32 and 32. Since the motors 16 and 17 are provided for each truck 4, the diameters of the motors 16 and 17 and the brake 18 decrease, and the height and width of the trucks 4 and 4 decrease. In addition, since the trolleys 4 and 4 are pivotally connected to the main body 8, as shown in FIG. 5, the overhead traveling vehicle 2 can smoothly turn a curve, and the work 04 is less shaken. Further, since the front and rear bumpers 6 and 6 are connected to the carts 4 and 4 by the pivot shaft 34, the bumpers 6 and 6 bend with respect to the cart 4 along the direction of the rail 01, and the other overhead traveling ahead by the proximity sensor 36. The vehicle can be reliably detected, and even if a collision occurs, the truck 4 can be prevented from directly colliding. On the other hand, if the bumpers 6, 6 are not pivotally connected to the carts 4, 4, the direction of the proximity sensor 36 is fixed to the direction of the cart 4,
It may happen that the traveling vehicle 2 ahead of the curve cannot be detected.

[0019]

[Winding Unit] FIGS. 6 to 8 show a winding unit 10 according to an embodiment. The hoisting unit 10 is supported by the lower portion of the main body 8, and a hoisting unit base 40 has three hoisting drums 42 disposed on the bottom surface thereof.
Each winding drum 42 is divided into two parts, and one rope 42 is used to wind two ropes, belts, tapes, or the like, and the hand 12 is wound using a total of six ropes 80. Further, the winding drum 42 is disposed, for example, along each side of the equilateral triangle, and a separation prevention roller 44 is provided outside the drum 42 as viewed from the center of the unit 10.
To prevent the rope 80 from coming off the drum 42.

Reference numerals 46 and 47 denote two sets of hoisting motors, in which brakes 48 such as electromagnetic brakes are separately provided. Reference numeral 50 denotes a motor shaft, 52 denotes a brake shaft, which is arranged in a substantially horizontal axial direction, for example, within a range of ± 10 degrees from a horizontal plane. As a result, the motors 46 and 47 and the brake 48 can be arranged substantially horizontally with the same height as the drum 42. A drive gear such as a hypoid gear 54 is provided at the center of the winding unit 10, that is, at the center of the triangle formed by the three drums 42, and a transmission spur gear 56 is provided on the common shaft 55.
The hypoid gear 54 converts the rotation of the motors 46 and 47 about the horizontal direction to the rotation about the height direction, and may use a bevel gear or the like. However, the hypoid gear 54 is preferable because the thin and reliable power can be transmitted. The spur gear 56 drives the drum 42 via a spur gear 58 on the drum 42 side. A bevel gear 60 is provided on the rotation shaft of the spur gear 58 to rotate the bevel gear 62 of the drum 42. Instead of the spur gears 58, 58, a helical gear or the like may be used.
64 is a guide pin for positioning with the hand 12.

The operation of the winding unit 10 will be described with reference to FIG. 7. The rope 8 is attached to three points of the hand 12, for example, the point P.
0, and from each point, the rope 80 is divided into two and extends upward, and the two drums 42, 4 arranged on two sides of the triangle are provided.
Wind up with 2. Here, when the hand 12 is at the lowest position, the rope 80 is inside the drum 42, and as the winding proceeds, the winding position moves to the outside of the drum 42.
As a result, the rope 80 is on an isosceles triangle with each point P as the vertex, and the interval between the winding positions of the two drums 42, 42 decreases as the hand 12 rises. For this reason, at the position where the hand 12 is located below, the interval between the winding positions is large, and when the hand 12 is raised, the interval between the winding positions is reduced, and the angle formed by the two ropes 80 fixed to the same point is determined by the hand 12. It can be almost constant regardless of the rise and fall of. For this reason, the hand 12 can be stably held irrespective of the height position, and the torque required for winding up becomes substantially constant.
That is, the larger the angle between the two ropes 80, 80, the more stably the hand 12 can be held, but on the other hand, the torque required for winding increases. In the embodiment, the angle formed by the two ropes is made constant regardless of the height, and the hand 12 is stably wound up or down with almost constant torque. In the embodiment, since the hand 12 is moved up and down using the six ropes 80, even if one rope is cut, the hand 12 does not tilt and the work 04 can be stably conveyed.

Next, the size of the winding unit 10 will be considered. 6 and 7, the motor 4
8 and the position of the drum 42 in the height direction are aligned and arranged substantially horizontally. For this reason, the height of the hoisting unit 10 is reduced, and the area occupied by the hypoid gear 54 and the spur gear 56 is reduced by overlapping them vertically. Considering the transmission of the rotation from the motors 46 and 47, the rotation of the motors 46 and 47 having the rotation axis in a substantially horizontal direction is converted to a substantially right angle by the hypoid gear 54, transmitted to the spur gears 56 and 58, and transmitted to the bevel gears 60 and 62. Then, the rotation is converted into a horizontal rotation again and transmitted to the drum 42.

The three drums 42 are on three sides of an equilateral triangle, and a space is created on a line connecting each vertex position and the hypoid gear 54 at the center. The motors 46, 47 and the brake 48 are arranged on this line, so that the plane size of the unit 10 can be minimized. In addition, since the brake 48 is separated from the motors 46 and 47, the size of each motor 46 and 47 can be reduced, and the drum 42, the motors 46, 47 and the brake 48 are arranged substantially uniformly around the hypoid gear 54, The load on the winding unit 10 is evenly distributed. As a result, the horizontal movement of the hoisting unit 10 using the later-described lateral movement rail 78 is facilitated.

[0024]

[Lateral movement of the hoisting unit] Lateral movement of the hoisting unit 10 will be described. 6, 7, and 9, reference numeral 70 denotes a lateral movement motor for laterally moving the hoisting unit 10 with respect to the main body 8, reference numeral 72 denotes a brake thereof, and reference numeral 74 denotes a pulley, which is driven by the rotation of the motor 70. A belt 90 is attached to the pulley 74, and a threaded shaft 92 is rotated. 94 and 96 are bearings, and 76 is a female ball screw. Of these members, the female ball screw 76 is attached to the hoisting unit 10, and the other members are attached to the main body 8. Conversely, the female ball screw 76 may be attached to the main body 8 and another member may be attached to the winding unit 10 side, but this is not preferable because the weight of the winding unit 10 increases. These are collectively referred to as a feed mechanism of a winding mechanism. Note that a simple cylindrical female screw may be used instead of the female ball screw 76. At the bottom of the main body 8, there are provided lateral movement rails 78, 78 shown in FIGS.
The forward and backward movement of the female ball screw 76 allows the hoisting unit 10 to move on the rail 78.

In this way, the female ball screw 76 moves forward and backward with respect to the threaded shaft 92 by the rotation of the motor 70, and the hoisting unit 10 moves on the laterally moving rail 78. For this reason, the work 04 located in a place other than immediately below the traveling rail 01 can be loaded and unloaded, and restrictions on the position of the work 04 are greatly eased. This means that restrictions on the arrangement of ground stations (not shown) are relaxed, and the ground stations can be arranged at desired positions. In addition, the degree of freedom in the arrangement of the traveling rail 01 is increased, and the installation of the rail 01 is facilitated.

The hoisting unit 10 with respect to the rail 01
The range in which the traverse can be
If the carriage 4 is fixed to the rail 01 in a stable manner, the range of lateral movement increases accordingly. Further, in the embodiment, the main body 8 is provided separately from the carriage 4, so that the lateral movement rail 78 is provided on the main body 8. However, if the main body 8 is integrated with the carriage 4, the lateral movement rail 78 is provided on the bottom of the carriage 4.
Will be provided.

[0027]

[Hand] The hand 12 will be described with reference to FIGS. In FIG. 10 and FIG. 11, 100 is the hand body,
It is suspended by a rope 80 from the winding unit 10.
Reference numeral 102 is a rotating plate, and the hand body 10 is driven by a motor 104.
Rotate with respect to zero. 106 is a brake, 108 is a shaft, 110 is a bevel gear connected to the shaft 108, and rotates a belt drive gear (not shown) to drive the toothed belt 112 and rotate the hand body 102. Reference numeral 114 is a mounting portion of the rope 80 (point P above), and 116
Is a positioning hole for the guide pin 64.

As shown in FIG. 11, the rotating plate 102 is provided with a substantially hemispherical centering member 120 and a spring 122 for pressing the centering member 120 downward, and the work 0
The holding plate 010 of No. 4 is engaged with the hole provided in the center and centered. Further, for example, 3 is provided on the rotating plate 102.
A set of chucks 126 is provided, and the chuck shafts 124 are rotated around the chucks 126 to fit into the recesses or holes provided in the holding plate 010.

Referring to FIG. 12 and FIG. 13, the related members of the chuck 126 are shown.
It is provided inside the, 130 is a motor with a brake, for example, 1
Reference numeral 32 is a bevel gear provided in the center of the cam plate 128, and reference numeral 134 is a cam groove. And the cam plate 128
Is rotated by a built-in motor 130 and is rotated by a bevel gear 132. A roller 136 is arranged in the cam groove 134 and driven by the rotation of the cam plate 128, the rotation of the roller 136 is transmitted to the gear 138, and meshes with the gear provided on the chuck shaft 124 to rotate the chuck 126. 14
Reference numeral 0 is a guide roller for smoothly rotating the cam plate 128.

Position of holding plate 010, that is, work 0
In order to detect the position of the upper part of 1, the work detection sensor is constituted by the light projecting section 142 and the light receiving section 143 using visible light, and the optical axis is arranged slightly above the fitting projection of the chuck 126. That is, the holding plate 010 is in a slightly raised position until the projection at the tip of the chuck 126 fits into the recess of the holding plate 010, and blocks the optical axis between the light projecting unit 142 and the light receiving unit 143. On the other hand, when the projection at the tip of the chuck 126 is fitted in the recess of the holding plate 010, the position of the holding plate 010 is relatively lowered, and the light from the light projecting unit 142 can be received by the light receiving unit 143. In this way, the chuck 126 for the holding plate 010 is
Detects if the hold of is complete. Although the transmitted light from the light projecting unit 142 to the light receiving unit 143 is used here, the reflected light or scattered light from the holding plate 010 is received by the light receiving unit 143.
Alternatively, the position of the holding plate 010 may be detected by a distance sensor such as an ultrasonic sensor.

As for the operation of the hand 12, the rotating plate 102 is rotated in advance before loading and unloading to rotate the workpiece 04 in the correct direction. When the hand 12 descends, the centering member 120 engages with the hole provided in the holding plate 010, and the position of the hand 12 with respect to the work 04 is finely corrected by the centering member 120 to perform centering. Although the hemispherical centering member 120 is used here, it is not limited to the hemispherical centering member 120 as long as it has a convex shape and a smooth tip. Further, by providing a protrusion for centering on the holding plate 010,
The hand 12 may be provided with a hole or a recess that engages with this protrusion.

When centering is completed, the motor 130
Thus, the cam plate 128 is rotated, and the roller 136 is driven along the cam groove 134. This rotation is the gear 13
8 rotation, the chuck shaft 124 is rotated, and the chuck 126 is rotated from the outer side to the inner side of the work 04.
The holding plate 010 is fitted and held in the recess provided in the holding plate 010.
Until the projection at the tip of the chuck 126 fits in the recess, the holding plate 010 is in a position slightly pushed up with respect to the hand 12, and the optical path between the light projecting unit 142 and the light receiving unit 143 is blocked. , It can detect that the retention is not completed. Similarly, even if the holding plate 010 and the chuck 126 are disengaged from each other while the work 04 is being conveyed, it can be detected because the optical axis between the light projecting unit 142 and the light receiving unit 143 is blocked.

[0033]

[Control] FIGS. 14 to 17 show control of the traveling motors 16 and 17 and the hoisting motors 46 and 47. Reference numeral 150 denotes a power supply board, which is supplied with power from the overhead lines 08 and 08 and includes two parts, an external power supply 152 for driving a motor and the like and a control power supply 154 for driving a control circuit. The external power supply 152 is, for example, 28V, and the traveling motor 1
6, 17 and hoisting motors 46 and 47, a power source V1 for driving the lateral movement motor 70 and the hand rotation motor 104, for example, a 24V power source V2, and for driving various sensors, a 24V power source, for example. Supply with V3. The control power source 154 is, for example, a 5V power source V4.
Supply. Reference numeral 156 denotes a main controller which includes a CPU and a memory, 158 denotes a communication modem, and 160 denotes a coupler for transmission and reception with the communication cable 03. 162
Is an input / output, which inputs signals from various sensors such as S1 to S3 and receives remote control signals such as infrared rays and ultrasonic waves.

Reference numeral 164 denotes a servo unit, which is a position calculation unit 168 for calculating a speed based on signals from the rotary encoders E1 and E2, and a position calculation unit 168 for calculating a position by integrating the speeds calculated by the speed calculation unit 166. Also, a target current determination unit 170 for determining a target value of the drive current with reference to the calculated speed and position. Among them, the rotary encoder E1 is, for example, a motor shaft 20 of the traveling motor 16.
Of the motor shaft 50 of the winding motor 46, for example, by the rotary encoder E2. Two drivers 172 and 174 are connected to the servo unit 164, and each of the drivers 172 and 174 has a current sensor 17 for measuring an output current (load current of the motor).
6,178 are provided. And drivers 172, 17
4 is a drive motor 1 via switches 180 and 182.
The connection can be switched between the 6 and 17 side and the winding motors 46 and 47 side.

Reference numeral 184 is a driver for controlling the lateral movement motor 70, and E3 is a rotary encoder for detecting the number of rotations of the lateral movement motor 70. Reference numeral 186 denotes a cable for controlling the hand control unit 188 by the main controller 156, which transmits a control signal from the main controller 156 to the hand control unit 188 and connects the power supply V2. This cable 186 is used for the hand 12
Also serves as a rope 80 for winding up or down.

The hand control unit 188 is provided with a CPU 190, a work detection unit 192, a servo unit 194 and a memory 196, and the work detection unit 192 is connected to the light receiving units 143, 143 and 143 of three work detection sensors. In the case of the descending control, in order to eliminate the error of each sensor, it is assumed that the work is detected by the majority logic of the signals of the three sensors and the work is detected when at least two sensors detect the work 01. . Further, in detecting whether the holding of the work 01 is stable or unstable, for example, when even one sensor detects the work, it becomes unstable and noise is removed. Therefore, when the work 01 is detected for a time longer than the width of noise such as chattering. The retention is unstable. The work detection unit 192 transfers a work detection signal to the main controller 156, and controls the hoisting motors 46 and 47 via the servo unit 164. Further, the servo section 194 controls the hand rotation motor 104 via the driver 198, and E4 is an encoder for reading the number of rotations of the hand rotation motor 104.

15 to 17, the traveling motor 16,
The control algorithm of the motor 17 and the hoisting motors 46 and 47 will be described. Traveling motors 16 and 17 and hoisting motor 4
It is not possible to drive 6 and 47 at the same time. When the carts 4 and 4 are traveling, the hoist motors 46 and 47 are stopped. Therefore, the servo unit 164 is the main controller 1
The presence or absence of a traveling command is checked by the signal of 56. When there is a traveling command, the switches 180 and 182 are switched to connect the traveling motor 16 to the driver 172 and the traveling motor 17 to the driver 174. In addition, a signal corresponding to the magnitude of the target current value is input to the drivers 172 and 174 according to the target speed. The drivers 172 and 174 have gains adjusted so as to correct slight deviations in output characteristics between the traveling motors 16 and 17, and supply equal driving currents to the motors 16 and 17 from the drivers 172 and 174. This drive current, that is, the load current of the motors 16 and 17 is monitored by the current sensors 176 and 178, and the drivers 172 and 174 are monitored.
To control the traveling motors 16 and 17.

Here, the fact that the load currents of the two traveling motors 16 and 17 are equal means that the output torques of the motors 16 and 17 are equal. And this is
This means that the traveling load of the overhead traveling vehicle is evenly distributed to the two traveling motors 16 and 17 and is synchronized.

The rotary encoder E1 detects the rotation speed of the traveling motor 16, here, the rotation speed of the motor shaft 20. No encoder is provided for the traveling motor 17. The signal from the encoder E1 is sent to the servo section 164
Is input to the speed calculation unit 166, and the speed calculation unit 166 converts this into the speed of the overhead traveling vehicle. On the other hand, the position calculation unit 16
8 integrates the speed of the overhead traveling vehicle and converts it into the traveling distance.
From these, the traveling state of the overhead traveling vehicle, that is, the speed and the position are determined, and when approaching the target position, the target current determination unit 17
In the case of 0, the target current is reduced to decelerate, and then the brakes 18, 18 are driven near the target position to stop the overhead traveling vehicle.

When the overhead traveling vehicle reaches the target position, the hoisting unit 10 lowers the hand 12. Hand one
2 is input from the main controller 156 to the servo unit 164, and switches 180 and 182 are switched to drive the driver 172 to the hoist motor 46 and the driver 1
74 is connected to the hoist motor 47. The number of revolutions of the hoist motor 46, here the number of revolutions of the motor shaft 50, is read by the rotary encoder E2, and the
No encoder is provided for 7. Since the traveling motors 16 and 17 and the hoisting motors 46 and 47 are both driven by the common power supply V1, the drivers 172 and 174 can also be used.

The raising and lowering starts by lowering the hand 12. Therefore, the servo section 164 inputs the target current value to the drivers 172 and 174, and the drivers 172 and 174 have already adjusted the gain so as to correct a slight difference in output characteristics between the hoist motors 46 and 47. Supply drive current. The drive current (load current) is detected by the current sensors 176 and 178, and the
174 is feedback-controlled. Further, the rotational speed of the hoist motor 46 is detected by the rotary encoder E2, and the lowering speed is controlled by the speed calculator 166, and the position of the hand 12 is detected by the position calculator 168. When the hand 12 approaches the stop target position, the servo unit 164 changes the target current value and decelerates the hand 12, for example.

FIG. 16 shows the operation after the hand 12 approaches the target position. Centering member 1 for loading
The work detection sensor detects the work in the vicinity of 20 in contact with the holding plate 010 at the upper end of the work 01. At this position, chucking is impossible, and the hand 12 continues to descend, and the descending distance during this time is read by the encoder E2, and the hand 12 is stopped when it descends for a predetermined length after the workpiece is detected. Therefore, chucking is possible, and the hand 12 stops while the centering member 120 performs centering. Here, the chuck 126 is rotated to rotate the workpiece 01.
Is held and the hand 12 is experimentally raised by a predetermined length.
Then, the state of the work detection sensor is closed (workpiece is detected)
It should change to open (without detecting the work). Depending on the stop position of the hand, the state of the sensor may change from open to open and then to open. Then, when the state of the work detection sensor changes from closed to open, the hand 12 rises because stable loading is performed, and when not, the hand 12 is lowered again to perform chucking again.

In the case of unloading, when the work 01 lands on the ground, the holding plate 01 floats from the chuck 126,
The optical axis of the work detection sensor is closed. Then, as in the case of loading, the hand 12 is lowered while detecting the descending distance by the rotary encoder E2 for a predetermined length, and then the chuck 126 is rotated to unload the load. Next, the hand 12 is lifted and moved to the next destination.

FIG. 17 shows the relationship between the lowering of the hand 12 and the state of the work detection sensor. The work detection sensor is located above the chuck 126, and its state changes from open to closed as it descends. If the descent is still continued, the state of the sensor changes to open again. And what is used in the embodiment is the change from the first opening to the closing and the change from the closing to the opening at the time of rising. Along with this, the rotatable position of the chuck 126 is a position where the hand 12 is lowered by a predetermined length after the state of the sensor is changed from open to closed. Note that it is possible to check the completion of the descent by changing from the state of the sensor to open → closed → open, but it is difficult to distinguish it from the noise in chattering in this way. . Therefore, in the embodiment, after the change from open to closed, the descending distance is read by the encoder E2 to confirm the completion of descending.

In the embodiments, the structures of the specific carriage, main body, hoisting unit, hand and the like are shown, but these are optional and the centering member or the like in the hand may not be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of an overhead traveling vehicle according to an embodiment.

FIG. 2 is a front view of a main part of a bogie section of the overhead traveling vehicle according to the embodiment.

FIG. 3 is a plan view of a main part of a bogie section of the overhead traveling vehicle according to the embodiment.

FIG. 4 is a cross-sectional view of a main part of the bogie of the overhead traveling vehicle according to the embodiment in a vertical plane.

FIG. 5 is a diagram showing a traveling state of the overhead traveling vehicle according to the embodiment on a curve of a bogie unit.

FIG. 6 is a front view of a main part of the winding unit according to the embodiment.

FIG. 7 is a bottom view of the winding unit according to the embodiment.

FIG. 8 is a diagram showing connection of a motor, a brake, and a hypoid gear in the hoisting unit of the embodiment.

FIG. 9 is a diagram showing a disassembled state of the hoisting unit in the height direction in the embodiment.

FIG. 10 is a view showing a disassembled state along the rotating plate of the hand in the embodiment.

FIG. 11 is a diagram showing a disassembled state of the hand in the height direction according to the embodiment.

FIG. 12 is a diagram showing a disassembled state along the cam plate of the hand in the embodiment.

FIG. 13 is a sectional view in the height direction of the main part of the hand according to the embodiment.

FIG. 14 is a control block diagram of the overhead traveling vehicle according to the embodiment.

FIG. 15 is an operation flowchart of the overhead traveling vehicle of the embodiment.

FIG. 16 is a flowchart showing the operation of the hand in the overhead traveling vehicle of the embodiment.

FIG. 17 is a characteristic diagram showing the operation of the hand in the overhead traveling vehicle of the embodiment.

[Explanation of symbols]

01 rail 90 belt 02 rail part 92 screw shaft 03 communication cable 94 bearing 04 work 96 bearing 05 support 100 hand body 06 cover 102 turning plate 07 ceiling 104 hand turning motor 08 overhead line 106 brake 09 mark 108 shaft 010 holding plate 110 bevel gear 2 overhead traveling vehicle 112 toothed belt 4 bogie 114 rope attachment part 6 bumper 116 positioning hole 8 main body 120 centering member 10 winding unit 122 spring plate 12 hand 124 chuck shaft 14 fall prevention member 126 chuck 15 cover 128 cam plate 16, 17 Travel Motor 130 Motor 18 Brake 132 Bevel Gear 20 Motor Shaft 134 Cam Groove 22 Brake Shaft 136 Roller 24 Hypoid Gear 1 8 gear 25 traveling shaft 140 guide roller 26 traveling wheel 142 light emitting part 28 guide roller 143 light receiving part 30 current collector 150 power supply board 32 pivot shaft 152 external power supply 32 pivot shaft 154 control power supply 36 proximity sensor 156 main controller 38 reading sensor 158 modem 40 Winding unit base 160 Coupler 42 Winding drum 162 Input / output 44 Disengagement prevention roller 164 Servo unit 46, 47 Winding motor 166 Speed calculation unit 48 Brake 168 Position calculation unit 50 Motor shaft 170 Target current determination unit 52 Brake shaft 172, 174
Driver 54 Hypoid Gear 176,178
Current sensor 55 Common axis 180,182
Switch 56 Spur gear 184 Driver 58 Spur gear 186 Cable 60 Bevel gear 188 Hand control part 62 Bevel gear 190 CPU 64 Guide pin 192 Work detection part 70 Lateral movement motor 194 Servo part 72 Brake 196 Memory 74 Pulley 198 Driver 76 Female ball screw E1, E2, E3, E
4 Encoder 78 Horizontal movement rail V1, V2
Motor power 80 rope V3
Sensor power supply V4 Control circuit power supply S1, S2, S3 Sensor

Claims (3)

[Claims] 1. A ceiling traveling provided with a main body supported by a traveling rail to travel, a winding unit provided at a lower portion of the main body, and a hand provided with a chuck for raising and lowering by the winding unit and holding a work. The vehicle is provided with a work detection sensor for detecting the work position in the hand, and a hand control means for stopping the descending of the hand based on a work detection signal from the work detection sensor. The feature is an overhead traveling vehicle. 2. The ceiling according to claim 1, wherein the hand control means is configured to further lower the hand for a predetermined length to stop the lowering of the hand after the work is detected by the work detection sensor. Traveling vehicle. 3. The work detection sensor, above the chuck, does not detect the work during stable holding of the work,
The overhead traveling vehicle according to claim 1 or 2, wherein the overhead traveling vehicle is provided at a position where a workpiece is detected when holding of the workpiece becomes unstable.