JPH0753504B2 - Loading platform - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a loading platform of a carrier vehicle that automatically travels in a workplace, and more specifically, three directions of two directions in a horizontal plane and a rotation direction around a vertical axis. Unidirectional positioning device.

[Prior art]

Transport vehicles, especially unmanned transport vehicles, have made great strides in the last few years as core devices in factory automation.

A conventional unmanned transport vehicle has a loading platform on the top surface for placing an article to be transported, and transports the article to a station provided in each step. Then, the transfer device provided in the station automatically transfers the article from the unmanned transport vehicle to each station.

On the other hand, the stopping accuracy of the automatic guided vehicle is about ± 10 mm with respect to the traveling direction and the direction intersecting with it, and about ± 1 ° with respect to the rotation direction around the vertical axis. Since the relative stop position accuracy depends on the stop accuracy of the automatic guided vehicle, it has the same value as the stop accuracy. Due to the error in the stop accuracy, a deviation occurs between the relative stop position between the transfer device and the loading platform and the regular relative stop position. When mounting, a structure that eliminates the deviation is provided in the transfer device or the transportation vehicle. Alternatively, it was necessary to improve the stopping accuracy of the automated guided vehicle.

As a publicly known means for improving the stopping accuracy, a plurality of hydraulic jacks are provided on an unmanned transfer vehicle, and a conical female hole is formed in the rod portion of the hydraulic jack. A plurality of positioning projections each having a conical male portion having a matching shape are provided corresponding to the mounting positions of the hydraulic jacks, and when the unmanned guided vehicle stops at the station, the hydraulic jacks are advanced and the positioning projections are moved to the outside. There is a means for fitting and positioning. As a result, the automatic guided vehicle is lifted from the floor and positioned at the regular stop position.

[Problems to be Solved by the Invention]

However, in the above-mentioned means, the positioning protrusions obstruct traveling, and a large number of additional equipment such as a hydraulic power source is required, resulting in an increase in price and a complicated structure. Further, since the means positions by the engagement of the female hole and the male part, the accuracy of the positioning is deteriorated due to the wear of the female hole and the male part, and dust is generated by the abrasion powder, such as in a semiconductor manufacturing factory. It could not be used in the environment where the positioning accuracy and cleanliness were specified.

Further, since the transfer device is provided for each station, if the transfer device is provided with a structure that eliminates the deviation,
Since a large number of such structures are required, the price of the entire system increases.

Further, when providing a structure for eliminating the above-mentioned deviation in the transport vehicle, it is considered that the traveling direction and the direction intersecting with it are positioned by using a ball screw, and the vertical rotation direction is rotated by a gear mechanism for positioning. However, the ball screw and gear mechanism require a lot of installation space, have a large number of parts, and are heavy, and the ball screw and gear mechanism have backlash. There was a problem that the cost was high. Furthermore, when a ball screw and a gear mechanism are used, dust due to abrasion powder is generated, and it is necessary to take a dustproof measure over a wide range.

The present invention has been made in view of the above circumstances, and performs positioning of a carrier loading platform in two directions in a horizontal plane and in three rotational directions about a vertical axis by using an eccentric cam having a preload applied to the outer periphery. Accordingly, it is an object of the present invention to provide a loading platform that is small in size and light in weight and can be positioned cleanly with high precision and at low cost by using low precision components.

[Means for Solving the Problems]

A loading platform according to the present invention is provided in an automatically traveling transportation vehicle, and includes a rotation platform rotatable about a vertical axis of the transportation vehicle, a first movable platform movable separately in two directions in a horizontal plane, and a first transportation platform. A loading unit having two moving bases, the driving unit being provided on each of the transport vehicle, the rotating base, and the first moving base, and including a plurality of eccentric cams and a drive motor for rotating the eccentric cams; A follower unit provided on each of the rotating table, the first moving table, and the second moving table, and having a cam groove for allowing the eccentric cam to roll while applying a preload to the outer circumference of the eccentric cam of each drive section. With and
The rotary movement of the drive unit is used to move and position the rotary base provided with the driven unit, the first movement base, and the second movement base in different directions with respect to the transport vehicle. .

[Action]

In the present invention, positioning of the stop position of the loading platform of the transport vehicle in two directions in the horizontal plane and in three directions around the vertical axis is performed.
An eccentric cam with a preload applied to the outer circumference is used to enable compact, lightweight and highly accurate positioning.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof.

FIG. 1 is a left side view of a carrier vehicle equipped with a loading table according to the present invention, and the direction of the carrier vehicle is indicated by a white arrow.

In the figure, 1 is supported by a pair of left and right driving wheels 2 (right driving wheel is not shown) and four auxiliary wheels 3 and 3 provided on the front, rear, left and right (right auxiliary wheel is not shown). It is an aircraft. The drive wheels 2 are attached to the center of the machine body 1 so as to be appropriately spaced apart from each other, and drive motors (not shown) are coaxially and directly connected to each other. The drive motors are individually driven to steer the machine body 1 and simultaneously drive them. Move Aircraft 1 forward and backward. Further, the auxiliary wheels 3, 3 are rotatably mounted around the vertical axis of the machine body 1 and are attached to the front and rear parts of the machine body 1 at appropriate intervals.

A loading platform 4 for placing an article to be conveyed is provided on the upper portion of the machine body 1 so that its center is the same as that of the machine body 1, and the loading platform 4 is provided in the central portion of the machine body 1 in the traveling direction of the machine body 1. Positioning means 5 in each direction for performing three-dimensional positioning in a direction orthogonal to the traveling direction and a rotation direction around the vertical axis of the machine body 5
It is attached to the machine body 1 so as to be movable and rotatable in the three directions by x, 5y, and 5θ. Further, the positioning means 5x, 5y, 5θ in each direction can be separately driven in the three directions by the driving units 6x, 6y, 6θ in the three directions. On the other hand, optical sensors 7 _A and 7 _B using an industrial TV camera for detecting the stop position of the body 1 are attached to the front and rear of the center of the body 1 at a distance L from the center of the body 1, respectively. The optical sensor 7 is provided with two positioning marks 8 and 8 on the floor 9 at the same intervals as the optical sensors 7 _A and 7 _B , in which a black square is drawn at the center of a white square, indicating the stop position of each step. detecting the stop position the machine body 1 _{by a,} 7 _B is imaged. Further, a positioning control device 9 is provided inside the machine body 1 to apply a drive signal to the respective drive parts 6x, 6y, 6θ from the positions of the imaged positioning marks 8, 8.

FIG. 2 is a partially cutaway side view showing each positioning means provided with the drive unit of the loading platform, which is an essential part of the present invention. The positioning means 5x, 5y, 5θ are attached to the front and rear of the central portion of the machine body 1. The base 57 is fastened and mounted on two brackets 12, 12 each having a rectangular flat plate fixed to the center of the vertical member of the inverted L-shape and having its longitudinal direction orthogonal to the traveling direction of the machine body 1. There is.

The base 57 is in the form of a square flat plate having a side slightly shorter than the length of the loading table in the left-right direction, has a cylindrical boss portion on the upper side of the central portion thereof, and a slewing bearing 52θ is provided inside the boss portion. A drive motor 66θ using a stepping motor for turning is attached to the lower side of the rear center of the platform 57 with its output shaft facing upward. An eccentric shaft 62θ having a predetermined amount of eccentricity with respect to the output shaft is provided at the tip of the drive motor 66θ via a flexible joint 61θ.
Are connected, and two ball bearings 63θ, 63θ, which are eccentric cams, are fitted on the upper end of the eccentric shaft 62θ. Also base 5
7 has a mounting flange in the lower part on the upper side of the rear center, a cylindrical bearing box 64θ is mounted coaxially with the drive motor 66θ, and the eccentric shaft 62θ is internally fitted to the upper end of the bearing box 64θ. Is supported by two ball bearings 65θ, 65θ.
A turntable 50θ, which will be described later, turns around a turning bearing 52θ due to the amount of eccentricity of the eccentric shaft 62θ.

The inner ring of the slewing bearing 52θ has a flat plate shape having substantially the same outer shape as that of the base 57, and a rotary table 50θ having a cylindrical boss portion downward in the central portion.
The boss portion is fitted inside, and the rotary table 50θ is rotatable by the swing bearing 52θ in the rotation direction around the vertical axis of the machine body 1 (hereinafter referred to as θ direction). . In addition, a bearing box 64 having a cylindrical shape at the lower center of the front part of the turntable 50θ and having mounting flanges at the upper and lower ends thereof, respectively.
x is attached, and a drive motor 66x including a stepping motor for moving in the front-rear direction (hereinafter referred to as x direction) is attached to the lower mounting flange with its output shaft facing upward. At the tip of the drive motor 66x,
An eccentric shaft 62x having a predetermined eccentric amount is connected to the drive motor output shaft via a flexible joint 61x, and two ball bearings, which are eccentric cams, are provided at the upper end of the eccentric shaft 62x. 63x, 6
3x is fitted. The eccentric shaft 62x is rotatably supported by two ball bearings 65x, 65x fitted in the upper portion of the bearing box 64x, and the first moving table 50x described later is supported by the eccentric amount of the eccentric shaft 62x. Move in the x direction. Further, four moving guides 52x, 52x in the x-direction, which are formed by using rail portions of the linear guides, are appropriately separated from each other on the front and rear portions of the rotary table 50θ, and their longitudinal directions are substantially aligned with the x-direction of the machine body 1 and attached. Has been.

FIG. 3 is an enlarged perspective view showing the mounting state of the eccentric cam, which is one of the constituent members of the drive unit, with respect to the loading table. The ball bearings 63θ, 63θ, which are the eccentric cams, have a rectangular flat plate shape and have a corner at one end. A lower cam receiver 54θ and a lower cam receiver 54θ that form a driven part having a rod-shaped convex portion and an elongated eccentric eccentric cam groove 59θ having a longitudinal direction in the same direction as the convex portion in the center thereof. The upper cam receiver 53θ is fitted inside the upper cam receiver 53θ formed with an eccentric cam groove 58θ similar to the lower cam 54θ mounted on the upper side of 54θ.
Is slidable in a direction orthogonal to the longitudinal direction of the eccentric cam groove with respect to the lower cam receiver 54θ by adjusting screws 55θ and 55θ that are screwed together in the longitudinal direction of the convex portion of the lower cam receiver 54θ. Yes. The lower cam bearing 54θ and the upper cam bearing 53θ are the eccentric cams, and the outer ring of the upper ball bearing 63θ of the two ball bearings 63θ, 63θ is the eccentric cam groove 58θ of the upper cam bearing 53θ.
Adjusting bolt 55 is pressed against the side surface on the θ side, and the lower ball bearing 63
Adjusting bolt 55θ so that the outer ring of θ is pressed into contact with the side surface of the eccentric cam groove 59θ of lower cam receiver 54θ opposite to the adjusting bolt 55θ.
Is adjusted by the above, thereby preloading each outer ring. When this adjustment is completed, the rotation of the adjusting bolt 55θ is blocked by the lock nut 56θ. The lower cam receiver 54θ and the upper cam receiver 53θ are attached to the center of the rear part of the turntable 50θ.

On the other hand, four upper guides 51x, which are formed by using rolling portions of linear guides that engage with the movement guides 52x, 52x ... Attached to the turntable 50θ and roll with respect to the movement guides 52x, 52x. 51
x ... is attached to the bottom of the first moving table 50x, the first moving table
The 50x is rotatable in the x direction with respect to the rotary base 50θ.

The first moving table 50x has a flat plate shape having substantially the same outer shape as that of the rotating table 50θ, and a bearing box 64y having a cylindrical shape and having mounting flanges at the upper and lower portions is attached to the lower center of the left side thereof. Has been. Further, a drive motor 66y, which uses a stepping motor for moving in the direction orthogonal to the traveling direction, that is, the left-right direction of the machine body 1 (hereinafter referred to as y direction), is attached to the lower mounting flange with its output shaft facing upward. ing.
An eccentric shaft 62y having a predetermined eccentric amount with respect to the output shaft of the drive motor 66y is connected to the tip of the drive motor 66y via a flexible bearing 61y, and the eccentric shaft 62y has an upper end portion. Two ball bearings 63y, 63y, which are eccentric cams, are externally fitted.
The eccentric shaft 62y is rotatably supported by two ball bearings 65y, 65y fitted in the upper portion of the bearing box 64y.
The second moving table y described later moves in the y direction due to the eccentricity amount. In addition, on the upper center of the front part of the first moving table 50x, the rotating table 5
Upper cam receiver 53θ and lower cam receiver 54θ mounted on 0θ
Upper cam receiver 53x and lower cam receiver 54x with the same structure as
Are mounted with the longitudinal direction of the eccentric cam grooves 58x, 59x as the y direction. Further, four y-direction movement guides 52y, 52y ... Using linear guide rail portions are attached to the right and left front and rear portions of the upper side of the first moving table 50x as appropriate. Then, the four upper guides 51y, 51y ... Using the rolling parts of the linear guides form a rectangular flat plate-like second moving table 50y.
Is attached to the lower portion of the second guide so as to engage with the movement guides 52y, 52y ..., And the second movement base 50y can be rolled in the y direction. Further, the lower left center of the second moving base 50y is engaged with the ball bearings 63y and 63y, and the upper cam receiver 53θ and the lower cam receiver 54y are engaged.
Upper cam receiver 53y and lower cam receiver 5 with the same structure as θ
4y is mounted with the eccentric cam grooves 58y and 59y having the longitudinal direction as the x direction and the upper and lower sides being opposite to the upper cam receiver 53θ and the lower cam receiver 54θ. A loading section 41 for loading the articles forming the loading table 4 is attached to the upper part of the second moving table 50y.

FIG. 4 is a block diagram showing the configuration of a positioning control device for a guided vehicle according to the present invention, in which the positioning control device 9 detects the positions of the positioning markers 8, 8 imaged by the optical sensors 7 _A , 7 _B. Center position of the visual field of the detection unit 91 and the optical sensor
Center of gravity position P _A ′ of positioning markers 8, 8 detected as P _A , P _B
The deviations from P _B ′ are calculated, and based on the deviations, the positioning correction values Δx, Δy, in the x-direction, the y-direction, and the θ-direction for positioning the loading table 4 of the transport vehicle in the direction for eliminating the deviation amount.
Positioning correction value calculation unit 92 for calculating Δθ and each calculated positioning correction value Δx, Δy, Δθ and each drive motor 66x, 66y,
The relationship with the number of pulses given to 66θ is memorized, and based on the memory, a predetermined number of pulses Lx, Ly, for each drive motor 66x, 66y, 66θ.
A motor drive unit 93 that gives Lθ is provided.

Next, a method of controlling the transport vehicle and calculating a positioning correction value at the stop position according to the present invention will be described. The positioning correction values Δx, Δy, Δθ are the drive parts 6x, 6y, 6θ of the loading table 4 in order to match the center position G of the loading table 4 and its x direction with the intermediate position G ′ of the positioning markers 8, 8 and its installation direction. The above deviation is eliminated.

FIG. 5 is a flow chart showing the flow of control.
Although the figure is for explaining the method of calculating the positioning correction value,
The transfer vehicle is automatically driven toward a station provided in each process by a predetermined guiding device, and the positioning mark 8,
The black circle at the center of 8 is stopped at a position where the visual fields of the optical sensors 7 _A and 7 _B can be captured. When the transport vehicle stops, the positioning markers 8 and 8 are imaged by the optical sensors 7 _A and 7 _B , and based on the imaging result, the position detecting unit 91 sets the intermediate position G ′ of the positioning markers 8 and 8 as the origin and sets the installation direction thereof. The distances d _XA , d _YA , d _XB , between the center positions PA, PB of the visual field and the positioning markers P _A ′, P _B ′ in a coordinate system with the X ′ axis as the Y ′ axis and the direction orthogonal to the X ′ axis.
d _{Calculate YB} . In the positioning correction value calculation unit 92, the respective positioning correction values Δx, Δy, Δθ are calculated by the calculation method described later from the respective distances d _XA , d _XB , d _YA , d _YB obtained by the position detection unit 91.
To calculate. Then, the motor drive unit 93 outputs the respective positioning correction values Δx, Δy, Δθ to the required pulses Lx, Ly, L of each drive motor.
Converted to θ, the required pulse numbers Lx, Ly, Lθ are output from the drive motors 66x, 66y, 66θ.

As a result, the loading platform 4 is positioned.

On the other hand, the calculation of each of the positioning correction values Δx, Δy, Δθ is performed when the position of the center of gravity of the positioning markers 8, 8 is captured within the field of view of the optical sensors 7 _A , 7 _B shown by the two-dot chain line in FIG. d _XA , d _YA , d
_XB , d _XY is required. The positioning correction values Δx, Δy, and Δθ are calculated by the following equations according to the calculated distances.

However, 2L: Installation distance of positioning mark 8,8 Each positioning correction value Δx, Δy, according to the above equations (1) to (3)
Calculate Δθ, output a predetermined number of pulses Lx, Ly, Lθ corresponding to each positioning correction value Δx, Δy, Δθ from the motor drive unit 93, and drive each drive motor 66x, 66y, 66θ to load the platform. Position 4 at the proper stop position. The amounts of movement and rotation in the three directions due to the amount of eccentricity are sufficiently large with respect to the amount of deviation (± 15 mm in the x direction and ± 20 in the y direction in this embodiment).
mm, θ direction ± 2 °), the relative positional accuracy between the loading platform and the transfer device is ± 1 mm in the x and y directions, and the allowable value in the θ direction, even if the transport vehicle stop accuracy is not sufficient. It became possible to keep it within.

Further, in this embodiment, since the eccentric cam using the ball bearing is used and the outer ring is preloaded, the structure of the positioning means can be simplified and the play between the eccentric cam and the eccentric cam groove can be suppressed. This enabled smooth positioning.

In this embodiment, the stepping motor is used as the drive motor, but the present invention is not limited to this, and any motor capable of position control such as a servo motor with an encoder may be used.

〔effect〕

As described above in detail, in the loading table according to the present invention, positioning in two directions in the horizontal plane and in three directions of the rotation around the vertical axis is performed by the drive unit using the eccentric cam having a preload applied to the outer circumference. As a result, the drive unit can be made compact and lightweight at low cost, and the stop position can be positioned with high accuracy.
The present invention has excellent effects.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a left side view of a carrier vehicle equipped with a loading table according to the present invention.
The figure is a partially cutaway side view showing the positioning means of the loading platform,
FIG. 4 is an enlarged perspective view showing the mounting state of the eccentric cam, FIG. 4 is a block diagram showing the configuration of the positioning control device, FIG. 5 is a flow chart showing the flow of control, and FIG. 6 is a method of calculating the positioning value. It is a figure. 1 ... machine, 5x ... x direction positioning means 5y ... y direction positioning means, 5θ ... θ direction positioning means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Sunao 4-17-88, Tsurumi, Tsurumi-ku, Osaka City, Osaka Prefecture Tsubakimoto Chain Co., Ltd. (56) Reference JP-A-60-107452 (JP, A) Sho 55-32376 (JP, U)

Claims (1)

[Claims] 1. A turntable that is provided in an automatically traveling transport vehicle and is rotatable about a vertical axis of the transport vehicle, and a first movable platform and a second movable platform that are separately movable in two directions in a horizontal plane. A loading platform having: a transport platform, a rotary platform, and a first moving platform,
A drive unit including a plurality of eccentric cams and a drive motor for rotating the eccentric cams, and a rotary base, a first movable base, and a second movable base, each of which is provided on the outer periphery of the eccentric cam of each drive unit. A driven portion having a cam groove that allows rolling of the eccentric cam while applying a preload to each of them, and a rotary base provided with the driven portion by the rotational movement of the driving portion, a first movement and a second movement. A loading platform, characterized in that the moving platform is configured to move and position in different directions with respect to the transport vehicle.