SU1355477A1 - Assembly robot - Google Patents

Abstract

This invention relates to robotics and can be used in mechanical engineering for automating an assembly. The aim of the invention is to simplify the design and improve the positioning. The robot operates in a rectangular coordinate system and contains frame 1 with work table 2, two working heads 13 and 14 mounted on carriages 11 and 12 connected to carriage 4. Carriages are driven by following pneumatic actuators whose pneumatic cylinders are aligned with pipe guides, and the pistons, consisting of two parts, connected by a spring, are connected to the carriage by means of flexible tapes, clinging to the rollers. The pneumatic drives of the carriage movement are equipped with linear photopulse position sensors consisting of a ruler mounted on a guide and a read head mounted on the carriage. The digital control system contains programmable controllers connected to the movement sensors with switchgear by braking devices and to the control computer of the upper level. 2 hp f-ly, 10 ill. I (L J3 16 with SD SP 4

Description

This invention relates to robotics and can be used in mechanical engineering for automating an assembly.

The purpose of the invention is to simplify the design and improve positioning accuracy.

FIG. 1 shows the assembly robot, a general view; in fig. 2 - upper and lower bridges; in fig. 3 - carriage with a pair of guides, front view; in fig. four -

Visible and has pneumatic diaphragm actuator movement.

The position sensor of each carriage consists of a ruler 44 mounted on one of each pair of carriage movement guides, and a reading head 45 mounted on each carriage opposite the reference ruler. The reading head 45 consists of a case with a mask 46 and a fastening strap 47, on which the carriage motion light-emitting device is mounted, a general view; on Yu are the radiators 48 and the photodetectors 49. The mark is a thumbnail. 5 - Norwegian; in fig. 6 - position sensor; in fig. 7 is a block diagram of a position sensor; in fig. 8 is a diagram of the location of the reference mark zero carriage position; in fig. 9 is a block diagram of an assembly robot control system; in fig. 10 - graphs of the formation of the reference signal zero.

The assembly robot contains a frame 1 with a working table 2 installed on it and, regarding the zero position of the sensor, is made in the form of a reflecting bar 50 having a pitch width at one of the ends of the support of the ruler, so that in the zero position of the carriage scientific research institute the label is opposite one of the two slots 51 masks. The position sensor also contains signal-shaping devices with a block 52 for detecting the direction of movement, a block 53 (device) of forming with signaling means 3, along which a 20 reference bar moves and a reversible counter 54,

connected to the control device 55.

the bridges comprising the carriage 4 and the brackets 5 and 6. On the carriage 4 and the brackets 5 and 6, perpendicular to the arrangement of the guides 3, guides 7-10 are fixed, along which the carriages 11 and 12 with the working heads 13 and 14 mounted on them, and the rotation and vertical movement drives of the tongs 15 and 16 are equipped with command execution sensors (not shown), with the carriages 11 and 12 mounted on the respective guides using a linear ball bearing 17 and rollers 18 and 19. The guides 7 and 9 are made in the form of a pipe, inside each one of them There is a piston 20, which transmits the force to the carriage through the belts 21 and 22, which run around the rollers 23 and 24 mounted on the carriage 4 and the brackets 5 and 6. The other ends of these belts are fixed in the sliders 25 and 26 connected to the carriage by means of bolts 27 and 28. The drive of the carriage 4 serves as a pneumatic cylinder 29, which transmits the force to the carriage through the belts 30 running around rollers 31 mounted on section 1. The piston of each carriage movement actuator consists of two parts 32 and 33 interconnected by a spring (compensator) 34, mouth mounted between the nut 35, connected to part 32, and the ring 36, connected to part 33 by means of a pin 37. The element of the piston 32 is connected to the tape 21, and the element 33 - to the tape 22. Parallel to the movement of the carriages 4, 11 and 12 are installed lanes 38, 39 and 40, with strip 38 fixed on frame 1, strip 39 on carriage 4 and bracket 5, and strip 40 on carriage 4 and bracket 6. Each of these brake lanes is located between the friction linings 41 and 42 of the braking device 43, mounted on an appropriate carriage. Moreover, the pad 41 is fixed, and the pad 42 pod30

35

The control device is an electronic digital computer, such as Electronics-60,

25 connected via a standard I / O interface 56 with execution control sensors 57 and 58 discrete command actuators, I / O teletype 59 and programmable controllers 60 controlling actuating follow-up pneumatic actuators that are connected to reversible counters 54 and discrete switching equipment 61 of the drives carriage movement.

Assembly robot works as follows.

Before assembling the next part with the base part mounted on the desktop of the robot 2 and interchanged with respect to its coordinate system, the control device 55 transmits to the controllers 60

40 controlling the follow-up pneumatic drives of the movement of the carriages information about the necessary movements, while the controller of the actuator of the carriage 4 receives the abscissa of the initial position intended for assembly of the part located in one of the

45 feeders in zone A (Fig. 2), the ordinate of the location of this part enters the controller of the drive of the upper bridge carriage 11, and the controller of the drive of the carriage 12 of the lower bridge receives the ordinate of the installation location of this part on the base. FIG. 2 are also indicated; B — operation zone of the upper head 13; C — operation zone of the lower head 14. Each of the controllers, having taken the values of these coordinates, compares them with the indicators of the corresponding position sensors and, by comparison, generates a command to move each carriage. At this command, the compressed air enters one or another cavity of the pneumatic cylinder and the piston 20 comes into motion

55

Visible and has pneumatic diaphragm actuator movement.

The position sensor of each carriage consists of a ruler 44 mounted on one of each pair of carriage movement guides, and a reading head 45 mounted on each carriage opposite the reference ruler. The reading head 45 consists of a body with a mask 46 and a mount plate 47 on which light emitters 48 and photodetectors 49 are mounted. The zero position of the sensor is made in the form of a reflecting bar 50 having a pitch width at one of the ends of the ruler support, so that The zero position of the carriage indicated by the label is located opposite one of the two slots 51 of the mask. The position sensor also contains signal-shaping devices -c with a direction-detecting unit 52 a block 53 (device) of forming a zero-point signal and a reversible counter 54,

0

five

The control device is an electronic digital computer, such as Electronics-60,

connected via a standard I / O interface 56 with execution control sensors 57 and 58 discrete command actuators, with I / O teletype 59 and programmable controllers 60 controlling actuating follow-up pneumatic actuators that are associated with reversible counters 54 and discrete switching equipment 61 motion drives carriages.

Assembly robot works as follows.

Before assembling the next part with the base part mounted on the desktop of the robot 2 and interchanged with respect to its coordinate system, the control device 55 transmits to the controllers 60

0 control of the following movement of the carriages by the movement of the carriages, information about the necessary movements, while the controller of the actuator of the carriage 4 receives the abscissa of the initial position intended for assembling the part located in one of

5 feeders in zone A (Fig. 2), the ordinate of the location of this part enters the controller of the drive of the upper bridge carriage 11, and the controller of the drive of the carriage 12 of the lower bridge receives the ordinate of the installation location of this part on the base. FIG. 2 are also indicated; B — operation zone of the upper head 13; C — operation zone of the lower head 14. Each of the controllers, having taken the values of these coordinates, compares them with the indicators of the corresponding position sensors and, by comparison, generates a command to move each carriage. At this command, compressed air enters a particular cavity of the pneumatic cylinder and the piston 20 comes into motion

five

moving, at the same time moving the corresponding carriage by means of flexible tapes. When each carriage moves, the raster optical coupling of the strokes of the reference ruler 44 with masks of the read head 45c modulates sinusoidal signals in photoreceivers 49, which are further converted into square and then pulsed in blocks 52 and 53, and using at least two pairs of photoreceivers and light insulation - readers are needed to determine the displacement of the read head 45 by the sign of the phase shift of the periodic signals modulated in the photoreceiver of each pair. The direction of movement is determined in impulse blocks 52 and 53.

The number of slots in the masks of the read head 45 is determined by the linear dimensions of the entrance pupil of the photodetector and is chosen so that the width

The zero signal is read by the position sensor as follows.

When the carriage moves due to a periodic change in the light intensity of the photoreceivers 49, their resistances change accordingly according to the laws:

RI L + a sin-0.t; R2 L -f and sin -f l;

where Ri is the resistance of the first photodetector;

R2 is the resistance of the second photodetector;

A - constant signal component;

a is the scale factor of the sinusoid;

D - the period of the strokes of the sensor line;

V is the speed of the carriage;

t - time

In this case, the sum of the resistances of successively connected photodetectors in a given mask was not less than a diameter of 20; the left position was constant and equal to

of the specified entrance pupil. In this case, if the mask slots coincide with the reflecting lines of the ruler 44 when the reading head 45 moves, the photodetector is as light as possible with a light emitter, illuminating half of the area of its entrance pupil, and the maximum amplitude of the output periodic signal.

The reversible counter 54 included in the sensor counts the incoming pulses from block 52 and transmits to the controller in parallel code the absolute value of the position coordinate of the corresponding carriage. According to the processing results received from the information sensor, the controller, using the algorithm programmed in it, generates and transmits control signals to the pneumatic actuator and its braking device and thereby realizes the positioning of the carriage in the given coordinate.

After the carriages 11 and 12 come out in two coordinates to the indicated point, the braking devices fix them in this position. Having received positioning confirmation signals from the controllers 60, the control device 55 sends a command to par 25

thirty

35

40

R «RI +, where (tc the resistance of the circuit of the reference channel zero in the zero position of the carriage (Fig. 10).

When the coordinates are zero, the periodicity of the illumination of one of the photodetectors is violated by the reference zero mark and both photodetectors 49 are maximally illuminated. Their total resistance is equal to

R «« B Rt + R2 2 (A-a), where the resistance of the circuit of the reference channel is zero in the zero position of the carriage;

RI is the resistance of the photodetector reading the origin signal at the zero position. At this moment, the zero signal in the photodetector circuit of the zero channel is modulated.

t and 1o p

tVrtWK

where 1o - current zero signal;

and external applied voltage. During operation of the robot, plastic stretching of the flexible head 13 on the gripping of the part and other ribbons in the movement drives can be made by moving it to the interface with the base part mounted on the table 2. This command is processed similarly to the cases considered. .

The upper head 13 in the assembly process carries out the mating of parts, and the lower head 14 performs, if necessary, auxiliary technological operations.

Before starting work, when the robot is turned on or when the coordinates are checked, the proTOK, the negative effect of which on the robot's dynamics, is eliminated by a compensator 34 installed between the elements 32 and 33 constituting the piston. The compensator works as follows. When assembling and adjusting the drives for moving the carriages by bolts 27 and 28 through slides 25 and 26, belts 21 and 22, the components of the piston 32 and 33 are maximally extended up to the stop of the pin 37

the process of operation of the head 13 and 14 is outputted to the 55 left end of the groove in the element 33. When

to its original position, and when the sensors read the zero signal, the values of the reversible counters are reset.

In this way, the spring 34 is maximally compressed, which ensures the preliminary tension of the flexible bands 21 and 22 and compensates for the zero-signal readout by the position sensor as follows.

When the carriage moves due to a periodic change in the light intensity of the photoreceivers 49, their resistances change accordingly according to the laws:

RI L + a sin-0.t; R2 L -f and sin -f l;,

where Ri is the resistance of the first photodetector;

R2 is the resistance of the second photodetector;

A - constant signal component;

a is the scale factor of the sinusoid;

D - the period of the strokes of the sensor line;

V is the speed of the carriage;

t - time

In this case, the sum of the resistances of successively connected photodetectors in the zero position is constant and equal to

R «RI +, where (tc the resistance of the circuit of the reference channel zero in the zero position of the carriage (Fig. 10).

When the coordinates are zero, the periodicity of the illumination of one of the photodetectors is violated by the reference zero mark and both photodetectors 49 are maximally illuminated. Their total resistance is equal to

R «« B Rt + R2 2 (A-a), where the resistance of the circuit of the reference channel is zero in the zero position of the carriage;

RI is the resistance of the photodetector reading the origin signal at the zero position. At this moment, the zero signal in the photodetector circuit of the zero channel is modulated.

t and 1o p

tVrtWK

tOK, the negative effect of which on the dynamics of the robot is eliminated by a compensator 34 installed between the elements 32 and 33 constituting the piston. The compensator works as follows. When assembling and adjusting the drives for moving the carriages by bolts 27 and 28 through slides 25 and 26, belts 21 and 22, the components of the piston 32 and 33 are maximally extended up to the stop of the pin 37

 the left end of the groove in the element 33. When

This spring 34 is maximally compressed, which provides a preliminary tension of flexible belts 21 and 22 and compensates for plastic stretching of said belts during operation of the drive by the amount of mutual convergence of the moving elements of the piston 32 and 33. At the same time, the spring 34 is always outside the power circuit: a loaded piston element - a tape - a slider - a carriage, and cannot compress at large accelerations, they appear in the drive during start and braking. In addition, the compensator produces a constant tension that is unloaded in the given direction of movement of the belt, thereby preventing it from sliding off the roller.

Claims (3)

1. An assembly robot containing a frame with a working table, two bridges with a drive for moving them, mounted on rails fixed on the frame, two carriages with a drive for moving them, mounted on rails located on bridges perpendicular to the frame rails, working heads with rotation and vertical displacement drives mounted on carriages, sensors for positioning bridges and carriages with reference devices of their zero coordinates and programmable digital control device, characterized in that, in order to simplify Designed to improve positioning accuracy, it is equipped with braking mechanisms for bridges and carriages, each of which is made in the form of a strip tensioned parallel to the respective guides, and friction linings with their movement mounted on the carriage and on the bridge with the ability to interact with the corresponding strip , while the bridges are located on both sides of the desktop, the guides are made in the form of two pipes, each of the drives you move / 5 filled in the form of a piston consisting of two parts connected by a spring and located in one of the pipes of the guide, and two belts, one ends of which are connected to the piston, and the other, respectively, to the carriage or to the bridge, and each position sensor is made in the form of a reflecting and light absorbing lines alternating with equal pitch mounted on a guide line, and a reading head located opposite to it, connected to the carriage or bridge, the head consisting of at least two pairs of photodetectors and light emitters facing the ruler, and between the photodetector of each pair and the ruler a mask is additionally installed, equipped with several transparent strokes with a step equal to the step of the ruler strokes, in addition, the masks of each pair of photodetectors and transmitter emitters are offset one 0 another by an amount equal to the ratio of the half step of the ruler lines to the number of pairs of photodetectors and light emitters. 2. The robot according to claim 1, characterized in that 5 the zero coordinate coordinate device is made in the form of two additional pairs of photodetectors and light emitters located in the read head, and slots are made in the mask, the distance between which is equal to an integer number of reflection steps: them and the absorbing strokes of the ruler plus the step plow, and the width of one of the reflective strokes of the ruler is equal to the step length; at the zero position of the carriage, this stroke is opposite one of the additional photoreceivers. five 3. Robot on PP. 1 and 2, characterized in that it is equipped with programmable controllers that connect the control device with the drives for moving carriages or bridges. 24 24 d W g In tfue.Z 18 7 /9 eight fie.Z if3 cg 2 FIG. 32 I 35 3 I 1 F 36 37 33 F / / FIG. five 6 9 L7 fie.b Fie.7 II11 Mil II ip: V / / D1 51 Fig.8 (f} ue.9