AU613054B2 - Perfected robot - Google Patents

Description

JJJIJL2 11111 1.4 111111.6 jjII.25 I1.4 iI Australia 6 1 Form PATENTS ACT 1952 COMPWLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: pplication Number, Lodged: 0 oo 00omplete Specification-Lodged: 0 Accepted: Lapsed: Published: Priority: 0 0 0 0 0 Related Art: TO BE CQMPLE~TED BY APPLICANT Name of Applicant: S.T.I.M.A. ENGINEERING DI MANIA DOTT. INC. ION C.S.n.c.

via Ripalta Arpina 26012 CASTELILEONE (Cremona) Italy Address of Applicant: ION MANIA Actual Inventor: Address for Service: CALLINANS Patent Attorneys, of 48-50 Bridge Road, Richmiond, State of Victoria, AustraliLa.

Complete Specifictitlon for the invntion entitled: "PERFECTED ROBOT" The following statement is a full description of this invention, including the best method of performirgj it known to me Note, The description Is to be typtd In doutzilde-,pqclng, pica typo face, in an area not exceeding 250 mm in dopti\t and 160 mm In width, en tough white paper of good quality and It is to be inserted Inside this form, -2- The need to supply machines that repeat the same processes on pieces already processed by other machines has led to a search for a mechanism that substitutes man to free him from an alienating work and reduce costs with machines acting even faster than man himself. Furthermore, the appearance of processes of principally chemical nature, and, more particularly, nuclear chemistry, has made it necessary to substitute man with automated mechanisms.

For this, since the years immediately after the end of the war, numerous mechanically operated machines have been developed, first with electromechanical and then electronic controls. Today the use of automated ,18, mechanisms is widespread with all highly repetitive mechanical processes. The simple name of automation has bee replaced iby a more imaginative, but universally adopted one of "robot", to define, in particular, an automated mechanism with various functions, of greater precision, more programmable with electronic ca. -s and in perspective also capable of making autonomous decisions.

Many roboticized mechanisms are noted, to which various functions have been imposed, but their application is linked to high precision of the movement that the terminal element or grippers can make, the. piece being generally gripped and its topographic size small with respec4 to the mechanical structure of the robot. In fact, even a small angular error at the base of the robot is amplified by the high ratio existing between body size of the robot and that of the piece to be gripped.

The clearances which the mechanical moving parts tolerate among one another are very impoitant for both initial mechanical processing and for the increase of said clearances arising from mtechanical wear due to friction.

Also, to have good practicability of the robot with respect to the variation of their topographic position, a wise possibility of adjustment of the gripper position is recessary before the order of damping or grip. For this

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-3equivalent multiple body adjustments are made, first to displacement of the human ody, i.e. practically of displacement towards the work station, and then to the angular depth adjustment on the piece to be processed, practically corresponding to the work of human hand and fingers.

It is also necessary that the grippers are motorized with practicable heads, not only fur universal displacements, as space coordinates, but also for reduced bulk, to penetrate between parts to be maintained or re-moved, but preserving a strong gripping power. This invention cafely meets all these Lteeds.

In fact, it reaches and grips the piece through, for examples, sev-en linear or 16 angular movements, three of them concentrated on the gripper. This remains slim and compact as motorization takes place without small motors placed in situ and without the bulk of cables which connect them to the electric system.

The head, which carries the grippers, is only moved with mechanical metal tubes which take their power from small motors located at the opposite end of the arm carrying the head.

Finally, a factor essential for the invention consists in the fact that the effect oi clearances, both of initial processing and derived from wear, are cancelled, creating a coupling between the driving mechanism and the driven mechanisms always in pair, the first being a driving element placed on fixed seat, while the second, coherent with the first, is instead placed on a support stressed to ensure tiht in the point of action the driven element always presses on the driving element. Also, to reduce wear, on all transfer mechanisms the noted method of the recirculating ball bearing, which changes the slip friction of all moving parts to a rolling friction between the balls and the parts in pressure on same.

To make the rhole innovative concept of the invention, in the robot S, afield clearer, even when mechanisms already noted in the mechanical field in '1 1. J .n alay in p. th s bi a' d e p o xde 20 wil h scn, oeen ih h irt i ntedpacdo aspor tese i; -4general are used, one of its applications to a typical robot structure i3 illustrated, using the enclosed drawings, from which the essentially innovative part can be deduced, overlooking small assembly particulars and worksho; methods noted in the techniques of the field. The enclosed drawings indicate: Fig. 1 the kinematic diagram of the proposed robot, indicating the movements required; Fig. 2 the diagram -f the reduction mechanism of the clearance between parts in mechanical u.-pling, in the drawing in the pairs of gearings; Fig. 3 a method of practically setting the sequence of the parts that S0 implement the movement of Fig. 1; Fig. 4 a method of obtaining a transfer of the base table according to axis X 1 of the diagram in Fig. 1; Fig. 5 indicates in plan how rotation Rb 1 of Fig. 1 is obtained applying the priniple of Fig. 2; Figs. 6A and 6B indicate how the abovementioned rotation mechanism appears in side view and vertical section; Figs. 7A, 7B and 7C indicate how vertical slip of the head of the robot carrying the arm is obtained; Fig. 8 indicates how at the top of the body of 7A, 7B and 7C is mounted the horizontal arm, complete with motors at one end, driving the metal tubes which lead to the opposite end towards the head; I Figs. 9 and 9B indicate in a vertical section and one in plane how the rotations move according to the angles of the grippers; Figs. 10A, 10B and 10C indicate how grippers clamping or expansion is obtained with rack driven by piston with large surface.

Fig. 1 schematically shows how it is possible, through an automated S mechanism fixed to the ground in a fixed point to grip an object placed 11 f in a different point in space, having as object its own axis of any inclination, The automated mechanism, which we call according to current use, "robot", has a body formed by a table, a vertical body and a horizontal arm, which reaches the object to be gripped by two movements of the table, one traverse along axis X 1 one of rotation of same for 360' Rbl, one of vertical traverse Z 1 for the vertical body, another of traverse along Y 1 of the horizontal body perpendicular to axis X 1 At the top of the horizontal arm the articulated head makes three angular adjustmenti, R 1 in the vertical plane of the arm, R 2 of rotation round the 13 axis of said arm, R 3 round an axis perpendicular to the former one.

With the coordinaitd succession of these movements, the robot fixed in has brought its grippers to centre the preferential coordinates and angles to be able to clamp with reciprocal slip of the grippers according to the concurrent lines F.

The following figures show a schematic application of the above principles on a robot model It should also be noted that the position of the grippers with respect to object must be sought with extreme precision in both the Cartesian and angular coordinates.

These movements should be soft and essentially independent from the clearance of the mechanisms and their wear state.

Fo. this reason, in this invention a double coupling is made between driving mechanism and driven mechanism, as schematically shown in Fig. 2, where we see that a cog-wheel is engaged in two wheels acting together, a first driving mechanism on fixed isupport like that driven imechanism, a second cooperating with the first supported by an elastic support, which forces driving wheel and driven wheel into immediate contact in the point where force P is I T i- ~I "Sr~ -6- 0

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4 exercised, including each reciprocal removal due to clearance of the mechanism.

The system applies for each mechanism of engagement.

Fig. 3 shows how the principles are put into practice in a robot.

On a hollow base 1, in which are mounted the movement mechanisms for traverse movements according to an axis X 1 perpendicular to the plane of the drawing, a table 2, capable of traverse movement, and a support 3, complete with rotation mechanism, which supports the vertical body 4 complete with motors and mechanisms of vertical elevation. At the top of said vertical body is mounnted the horizontal arm 5, complete with motor and devices of slip along the 10 axis Y 1 perpendicular to X 1 *At one end of said arm is mounted head 6 with two axes Y 1 and tl, S incorporating the rotation mechanisms R 1

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2 and R 3 Said horizontal arm carries at the opposite end to the head three motors which guarantee said movements without any connection blocking the section of the head and arm.

Along the second axis t 1 of the head are mounted the expandable claws 8, each driven by a suitable double rack.

In particular, in Fig. 4 it is schematically indicated how table 2 moves back and forward in one direction or the other, with respect to hollow base 1.

This transfer is made by means of operation of a motor 10 which presses in rotation a recirculating ball nut 11 round a threaded shaft 12 placed in hollow base 1, motor and nut 11 made integral by a support or similar 13 to the lower part of table 2.

To prevent possible clearances between the balls of nut 11 and the screw of shaft 12, said threaded shaft 12 is adjustably preloaded, at one end, by return spring 14.

Fig. 5 shows how rotation of support 3 is obtained through elimination /Ci i Pj INc

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-7of the influence of clearance. It is seen, in fact, how a bevelled gear 30 integral by keying to axis 39 supporting the vertical body and a ring gear 31 are engaged in two worm screws 32 and 32', which rotate at the same sp',ed from the opposite side of the gear, generating two thrusts V and V 1 which make the ring gear rotate according to Rb 1 The two screws are moved by a single motor 33, which rotates, by means of a couple of pulleys 34 with toothed belt, the screw 32, at a given speed, while, by means of a couple of pulleys 35 and a couple of gears 36, it conducts the screw 32' at the same speed as 32.

The two screws 32 and 32' act in synchronism on the bevelled gear but 19 shaft 36 of screw 32' is supported in contrast with thrust by the axially elastic support 37', while axis 36 rotates on a rigid support and from i' a so called "encoder" 38 is derived. Here an application of the general principle illustrated in Fig. 2 is practically accomplished.

Figs. 6A and 6B show the above mechanism in side view and median section.

Figs. 7A and 7B show the vertical module 4 formed by two coaxial elements 41 and 42 sliding from one to the other telescopically, an element 41 being fixed to base 40 integral to the rotating table, element 42 being integral with the upper head 43 to the horizontal arm 5. Operation of the telescopic movement is obtained by means of a motor 44 made integra to the hollow base 40, in which power is transmitted, through a couple 45 of pulleys with toothed belt, to the shaft of a worm screw 46, rotating in a multiple ball support, coupled with a recirculating ball nut 47 integral to the sliding element 42. The slip of said element is guided by a slider with two vertical blades 48 sliding between two recircui.ting ball chutes 49 obtained at the top of fixed element 41, as can be better seen in Fig. 7C, which illustrates a section according to a plane of layout VII-VII. The weight of the driven mechanism is the element of contrast that ,V "T l elimizates the influence of vertical clearance between the two parts driven and driving, while the position and ball structure of chute 49 essentially cancels lateral skidding.

Fig. 8 shows the construction of horizontal arm 5, which is connected and made integral to the head of the vertical element by a motor 51, through the couple of pulleys 52 with toothed belts, rotating on a multi-sphere belt 53 and operating with a recirculating ball nut 54 made integral to tubular support 55. At the two ends of said tubular elerment, capable of sliding along axis Y 1 YI are mounted from one side the coupling ring nut 56 of the head with the concentric 19 supports of two metal- tubes and the central shaft, from the opposite side three motors 57-57'-57", flanked and operating by means of an equal number of pulleys with toothed belts 58-58'58" a first metal tube, the central shaft and the second metal tube. In this way the tube of the horizontal arm remains completely smooth on the outside, free from cables or other transmissions, while the withdrawal of the small motors to the rear limit makes it possible to reduce the overall dimensions of the head near the coupling space to a minimum. This increases the practicability of the operating head in the work area.

Figs. 9A and 9B show two sections of head 6 which can be coupled on the horizontal arm 5, by means of ring nut 56, entering collar 60. In the head, through bevel gears 62 driven by central shaft 63, rotation R 3 of the driven shaft 64 integral to the grippers-holder ring nut 65 is determined. In the same head, through the end of a metal tube engaged in teeth of head 66, a second gearing 67, capable of making the support in which the second axis 64 rotates rotate according to R 1 Finally, the second metal tube can make the entire head rotate round axis Y 1

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1 in a normal plane in the drawing. It is thus possible, starting from small motors 57-57'57" to obtain all required angles at the central axis of the 9P -9grippers. The grippere, fixed to ring nut 65, are driven by two :racks 81-81' which force the grippers 82-83' or the gearing to approach or move apart, guided by chutes 83-83', as shown in Fig. In Figs. 10B and 10C, which show a section with layout X-X, we see how a couple of pistons of large surface area 84 commands withdrawal (Fig or approach (Fig. 10C) of the grippers. The mechanical particulars of assembly and coupling forming part of the common technique and therefore not particularly claimed are not indicated or described in detail. However, with the described devices movements on the "fingers" can be obtained or grippers with precisions of 1/10 of millimetre, precision preservable in time.

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Claims (9)

1. A multifunctional robot or automaton, being electrically or electronically controlled externally of said robot, said robot including a rotatable base table, a vertically disposed body on said base table, a horizontal arm on said vertically disposed body and a gripper means on said horizontal arm, wherein positioning of said gripper means is controlled by three directional movements of said vertically disposed body and said horizontal arm together with rotation movement of said base table, coupling of said vertically disposed body and said horizontal arm being designed to overcome slackness caused by manufacturing tolerances or wear and all other couplings in said robot using a recirculating ball nut.

2. The robot according to claim 1, wherein said base table is horizontally moved in one direction or the other by a motor connected to a recirculating ball nut rotating round a threaded shaft adjustably prloaded at one end.

3. The robot according to claim 1 or claim 2, wherein said table is rotated up to 360 due to the action of a double worm screw coupling, in which a stress is applied along the axis of one of said worm screws.

4. The robot according to any one of claims 1 to 3, wherein the body is formed by two elements with telescopic slip controlled by a vertically disposed worm screw rotating on recirculating ball nuts, a movable telescopic element being guided on a fixed telescopic element by a double laminar slider sliding in double slip seats.

The robot according to any one of claims 1 to 4, wherein the horizontal arm slides to and from the vertical, disposed I ody due to the movement of a screw acting on a recirculating ball nut.

6. The robot according to claim 5, wherein said horizontal arm has a tubular structure with a central axis and at least two concentric metal tubes rotatable by three small motors located at a rear end, said tubes terminating at r ,r a front end on concentric supports and being fitted with axial tooth projections for coupling on seats of said gripper means.

7. The robot according to any one of claims I to 6, wherein directional movements are obtained by means of three angular adjustments using ring gears driven by metal tubes rotating inside said horizontal arm.

8. The robot according to any one of claim 1 to 7, wherein said gripper means is mounted on a rotating vertical axis are driven by parallel slip of two racks driven by a piston.

9. A multiffunctional robot or automaton as claimed in claim 1, substantially as described herein with reference to the accompanying drawings. DA T ED this 9th day of May, 1991. S.T.I.M4.A. ENGINEERING DE MANIA DOTT. ING. ION C.S.n~c. By its Patent Attorneys: CALLINAN LAWRIE