IT8320363A1 - METHOD AND EQUIPMENT FOR PROGRAMMING A ROBOT - Google Patents

Description

Description of the Invention which is entitled:

? METHOD AND EQUIPMENT FOR PROGRAMMING A ROBOT ",

SUMMARY

The present invention relates to a method and an apparatus for programming in a simple, economical but nevertheless precise and reliable way, a mobile robot with continuity. , whose movement sequences are controlled by motorized operators controlled by electrical output signals coming from a programmable memory, so that the robot is moved manually in the desired way during the programming phase and the movement sequences during this programming phase are stored in a memory in the form of electrical signals. The method includes in particular the steps of fixing a handle having a plurality of of sensors, to the said robot in a position. of sensors, in a different position on the robot, move the latter according to a desired sequence of movements by means of the said handles, connect the signals coming from the sensors placed in the handles directly to the motorized operators for robots, and simultaneously store these signals as signals programming (F1g. 1).

The present invention relates to a method and an apparatus for programming a robot and more? particularly an apparatus incorporating two programming handles which can be operated simultaneously, each to provide programming according to multiple functions. axes or coordinates. Apparatus have been proposed for programming a robot with a continuous path, in which the movement sequences are controlled by motors controlled by electrical output signals coming from a programmable memory. The robot? manually moved as desired during a programming process and movement? Stored in the memory in the form of electrical signals, after which these signals can drive the motors in the course of a subsequent operation. These robots have been found to be of advantageous use in spray painting processes, in which there is a spraying sequence that can be interrupted and a sequence for replacing the workpiece. In such systems? It is necessary that the robot is counterbalanced as regards the movable arms and that the control mechanism of the individual axes allows to carry out a sequence of movements suitable for being controlled by externally available control signals. In many known robots there is an energized transmission to control the robot arm, and with these robots it is difficult to carry out a programming procedure in which the arm is moved manually by an operator through a sequence of movements. When is such a type of robot used,? It is possible to move the robot arm manually only when coupling means or the like are provided for disengaging the controls. Are these robots sometimes equipped with an additional arm, called the prographing arm. does it have the same number of degrees of freedom? of the main arm? but it constitutes a device equipped with sensors that can? be easily moved manually to follow the manipulations of an operator. However, these programmer arms are relatively complex and expensive and require that they be adjusted to the same position that the robot assumes during its normal work sequences. Other robot controls have been suggested that use a single handle to produce controllable robot programming signals, but still a single handle system? relatively complicated and expensive and is relatively heavy, due to the need to house a large number of sensors. Furthermore, a single handle control provides programming signals which are relatively inaccurate and are sometimes difficult to process in a computer. The use of a single handle also entails the need for a fast and therefore expensive computer to rapidly manipulate the various signals produced.

The main purpose of the present invention is now to propose a method and an apparatus for programming a robot in a simple and economical, but nevertheless precise and reliable way.

According to an embodiment of the present invention, two handles are fixed in suitable positions on the robot for programming, providing signals to a unit. programming and control. The unit command programming? in turn connectable to the control element and / or to the robot command, to control the mechanical parts of the robot during

operation. In the course of the programming, emperor grasps the grips and d? start at the desired movements. Sensors placed in the handles detect their movements and produce signals which are fed to the unit? programming command, which stores digital signals corresponding to the movements of the handles. To the operator? only minimal force is required to manipulate the handles, why? Not ? need to provide the operating force with which the robot? commanded. Each of the two handles incorporates more? sensors to detect signals according to pi? axes, so that a plurality? command signals are simultaneously produced by each of the two handles. There? allows a simplification of the unit? of command of the programming, since? the signals developed by the handles are precise and the fact that they are available simultaneously makes it possible to use a computer more? slower and less expensive than those previously used to process signals.

In carrying out the present invention, neither is required. special the grafts for s to engage the commands, n? means to counterbalance the center of gravity of the robot components. The programming handles are detachable after the programming process, so that they can be used to program another robot.

The present invention illustrates an economical programming process, since? it allows high transmission ratios between the drive and the articulation, without interfering with the programming process, and also makes it possible to use relatively small and cheap drive motors since they are not? no center of gravity counterweight required.

These and other objects and advantages of the present invention will become apparent from an examination of the following description and the accompanying drawings, in which; figure 1? a schematic view of the installation as a whole, for illustration of the present invention;

figure 2? a longitudinal sectional view of a programming handle for movement along three axes;

Figure 3 illustrates a modification of the handle of Figure 2;

Figure 4 illustrates a further modification of the programming handle;

figure 5? an elevation view of the handle of figure 4;

figure 6? an operation block diagram illustrating signal processing;

figure 7? an operation block diagram, illustrating the conversion of handle signals into coordinates for the robot *

Referring initially to Figure 1, in it? illustrated a robot 10 that has 6 degrees of freedom? or 6 axes ^ -a6. The axis a ^? a vertical axis, while the axes a2-a4 are all horizontal axes, around which some sections of the arm are rotatable. The axes a ^ -ag are orthogonal with respect to the axis a4, so that the extremity? of the robot arm can? be positioned in any position. A conventional paint spray gun 11? connected to the extremity? free front of the robot arm.

Furthermore, ? expected a unit? and control circuit 12 which contains signal processing and control circuits which will be described more? dictate- "gliat sniente later.

Two handles 13 and 14 are connected to different parts of the robot arm, the front handle 14 being connected to the paint spray gun 11, while the rear handle 13? connected to the robot arm between the axes a3 a4.

Both handles are connected to the arm

of the robot in a detachable way, so that they can be removed when not used to program the robot arm. Both handles are connected via cables 13a and Ma to the unit? programming and control 12. How? shown in Figure 1, the rear programming handle 13 detects three orthogonal axes Xh, Yh and Zh, while the front programming handle 14 detects two straight axes YVo and Yvu, as well as? a rotation movement Zv around the longitudinal axis of the gun 11, derived from the signals YVo and Yvu.

An illustrative embodiment of the rear programming handle? shown in longitudinal section in Figure 2. The handle 13 has a hollow internal core 20 having an upper end flange 20a adapted to be fastened to the robot 10 by means of screws, bolts or the like. The soul 20? surrounded by the casing 21 of the handle, which? it is preferably flexible and can be displaced with respect to the core 20 along three axes Xh, Yh and Zh. Individual wall sensors are provided for detecting movements according to each of the axes, each sensor having a spring to determine a normal or rest condition thereof. For the x axis? a sensor 23x is provided, interposed between the core 20 and the external part of the handle 13, while a spring 22x? interposed between the core 20 and the external part of the handle diametrically opposite to the sensor 23x and serves to push the core 20 towards the outside of the handle 13, where? placed the sensor 23x. The corresponding 23y sensor? mounted in an orthogonal position to the sensor 23x? to detect the movement in the Y direction, and it too has a spring corresponding to the spring 22x for the X axis. lower soul 20? disposed a sensor 23 z to detect movement in the z direction, sensor which? interposed between the core 20 and a terminal plug which closes the bottom of the handle 13. A spring 22z normally urges the end plug downwards with respect to the core 20, to determine a normal or rest position for the sensor 23z. A safety switch 24? mounted in the external part of the handle 13 and? adapted to operate in the mode of an "auto stop" switch, so that the programming equipment is only operational when the operator's hand is in operation. positioned on the handle 13 so as to activate the switch 24.

Each of the sensors and the switch 24 are connected to the programming and control apparatus by means of one or more? cables, illustrated in figure 2 with the references I 3ax, I 3ay, I3az and 24a.

It is evident that, although in fig. 2 lines for four signals are illustrated,? possible to provide lines for one or more? additional signals, to establish a common reference connected to a second terminal of each switch or sensor.

The switch 24 operates to open or close the connection between its line 24a and a reference potential, while each of the sensors provides the variable signal on its respective command line, so that the voltage or current present on the line indicate the relative position of the sensor.

Figure 3 illustrates an illustrative embodiment of the front handle 14? It has a hollow internal core 30, with an upper end flange 30a adapted to be fixed to the gun 11 by means of bolts, screws or the like. Three sensor-spring pairs are arranged in the handle, namely a 32yo spring and a 33yo sensor for l? YVo axis, a 32yu spring and a 33yu sensor for the YVu axis and a 32zv spring with a 33zv sensor for the Zv axis. The sensor for the Zv axis? disposed between the core 30 and an end cap which closes the end? bottom of the handle 31, to detect movement in and around the longitudinal axis of the handle 31. The sensors 33yo and 33yu are adapted to detect the movement of oscillation or rotation around an axis normal to the plane of the drawing on which fig.3 appears. Each of the sensors? connected to the unit? 12 of programming and command by means of command lines 14 which include lines 14ayo, 14ayu and I4azv.

Although not shown in fig. 3, the handle 14? also preferably equipped with an automatic stop switch similar to the switch 24 of the handle 13. This switch 34? illustrated in fig. 1?

In operation, during the programming phase the handles 13 and 14 are connected in the suitable points of the robot 10 and of the spray gun 11, how? illustrated in fig. 1. If desired, an automatic zero registration is performed when the unit? command 12? inserted, before the handles are grasped. The operator grasps the two handles and presses the safety switches 24 and 34 to cause the robot to operate. When either of the switches 24 and 34? released, the command of the robot? off.

By holding the programming handles, the operator moves these handles to perform a work cycle, moving the robot arm and spray gun as desired. The force exerted by the operator on the casings 21 and 31 of the handles during this procedure causes a relative movement of the three sensors 23 of the handle 13 and of the three sensors 33 of the handle 14, such as to produce signals on the corresponding signal lines directed to the unit? control 12. These signals correspond to the direction of the force that is applied to the different handles by the operator. Based on these signals, the unit? 12 controls the robot drive motors in such a way that the motorized control of the robot is controlled to do so. that the robot arm and the spray gun carry out the movements corresponding to the direction of the forces applied by the operator to the handles d? programming. Do not ? It is necessary that the operators exert excessively high forces on the programming handles, since? the movements of the robot arm and spray gun are controlled by the normal motorized operators of the robot complex. At the same time, the sequences d? movement are stored in a conventional way in the memory of the robot, programming so? the robot.

The programming procedure described above can? to be carried out without emitting paint through the spray gun; or alternatively can? to be carried out with the emission of paint. In this last case, in the front handle 14? a switch is arranged to operate the paint valve and this switch is operated at times when paint remission is desired. After programming is complete, the handles 13 and 14 can be removed from the robot arm and spray gun, while the control lines between the programming handles and the unit are removed. 12 are detached.

Figures 4 and 5 illustrate an alternative embodiment of handles which can be used to constitute the front programming handle 14. The handle of Figures 4 and 5 has an internal core 40 which? surrounded by the handle shell 41. A 42 leaf spring? interposed between the core 40 and the inside of the casing 41, while two wire strain gauges 43 are mounted on the leaf spring. The Mayo and I4ayu lines for signals

are attached to the strain gauges and provide signals to the unit? 12 for programming and command, in response to the bending of the leaf spring 42 due to the force applied between the casing 41 and the core 40. Two leaf springs 44 are provided for the z axis and are fixed between the core 40 and the housing of the spray gun 11, while an I4az line for signals connects strain gauges mounted on springs to the unit? 12 for programming and control to provide signals corresponding to the bending of the two leaf springs 44. A safety switch 45? mounted on the handle and on the same? also mounted a paint valve control switch 46.

1 two switches are connected to the unit? 12 programming and command by means of further command lines (not illustrated).

The operation of the handle illustrated in figures 4 and 5? similar to the one described above, with the exception that strain gauges are used to send the force detection signal to the location of the sensors described above with reference to Figures 2 and 3.

When the handle of figures 4 and 5? used, the movements along the axes a5 and a6 are determined by the sum and difference, respectively, of the two signals yo and yu. The sum of the two signals? relative to a force directed in a straight direction, while the difference between the two signals? relative to a twisting or rotational force. When ? once the programming operation of the equipment has started, the a1 rest values of yo and yu are measured, with a correction applied to each of them so that the sum and the difference are both equal to zero. The generation of a zero point signal has the advantage of significantly facilitating a registration of the equipment.

The present invention is not? limited to the illustrated exemplary embodiments of the handles. Alternatively, for example, two handles could respectively command a different plurality. of robot joints. Furthermore, the sensors can be of any desired type, as? It is only essential that they generate command signals corresponding to the applied forces. The command signals can be processed by means of standard computers and processors, as will result? evident to oar experts. An exemplifying provision through which can? be carried out this processing,? illustrated in figure 6.

According to Fig. 6, the analog signals fed by the handles 13,14 are initially amplified in the analog amplifier 100 with partial decoupling and identification of the limit values. The amplified signals are then converted into digital signals in the multiplexer and converter AD 101, and then fed to the programming computer 102 in which a digital decoupling, a correction from the digital signals to the robot coordinates and a digital adjustment are carried out, the components 100, 101 and 102 belonging all to the unit? command 12. This unit? ? connected to the robot 10 through a bus system 103, connected in turn bi-uniquely to the axis commands al, a2, a3, a4, a5, a6, respectively 104, 105, 106, 107, 108, 109. The same system 103? moreover connected to a central computer 110 having inputs 111 and outputs 112, to a safety computer 113, with inputs coming from safety circuits 114 and one or more? outputs for an alarm 115, as well as? to an apparatus 116 of evaluation and memorization, as well as? for selecting the program, having inputs corresponding to the controls 117 of the valves of the automatic guns, the signals 118 for selecting the program and for starting it and 119 for regulating the speed. With the arrangement of handles according to fig. 1, the conversion on the robot coordinates is carried out with a modality? in-line feed, as shown in fig. 7. With reference to Fig. 7, the signals yh and zv can be directly assigned, through the elements 120 and 121 for determining the nominal value, to the motorized operators (robot adjustment servocircuits 122 and 123) of the axes ai and a4 respectively. The signals xh and z? I (of the rear handle) produce, through the apparatus 124, the command signals for the motorized operators 125 and 126 of the axes a2 and a3, in conjunction with the and the cosine of the angles? 2 and 3 around these axes. The sum signal of the front handle, Yvo Yv, emitted by component 127, d? place to a variable command, in 128, for the axis a5, while the difference of signals Yvo? Yvu d? gives rise to a variable command, at 129, for the rotation movement around the axis a6. The control signals are fed to the robot in the form of control signals, carrying out a control relative to all the controlled axes. At the same time, the signals are also written into the robot's memory. The memory is that? scheduled. Logic elements are provided for the choice of the program, the choice of the speed, the start-up, the command of the tool, etc., together with a circuit

Claims (12)

1) Method for programming a continuous motion robot, whose motion sequences are controlled by motorized operators controlled by electrical output signals from a programmable memory, so that the robot is moved manually in the desired way during the programming and the movement sequences during this programming step are stored in a memory in the form of electrical signals, the method comprising the steps of: connecting a handle having a plurality of of sensors to said robot in one position; connect a second handle having a plurality of of sensors to said robot in a different position; moving the said robot through a desired sequence of movements by means of the said handles; connecting the signals derived from the sensors within said handles directly to the motorized operators of the robot; and simultaneously storing said signals as programming signals. 2) Method according to claim 1, wherein the sensors of each handle detect the movement around three independent axes. 3) Method according to claim 1, wherein some of the signals generated by the sensors are sum signals, at least one signal being however a differential signal. 4) Method according to claim 1, wherein the signals generated during the program process are subjected to a comparison with limit values, the movement of the robot being interrupted following the exceeding of a limit value. 5) Method according to claim 1, wherein said handles are detachably fixed. 6) Method according to claim 1, comprising the step of stopping the movement of the robot when the operator leaves the handle. 7) Method according to claim 1, comprising the step of carrying out an initial correction on the zero point of the signals emitted by the sensors, before grasping the handle. 8) Method according to claim 1, comprising the step of feeding the output of the programming and control device to the robot on a single divided line, and of using the control means of the robot to feed the control signals to the motorized operators of the robot on one side and to the memory of the robot control means, on the other side. 9) Apparatus for carrying out the method according to claim 1, comprising two handles that can be connected to the robot and / or to the tool carried by the robot, each of said handles being constituted by an internal core, by a casing which can be moved with respect to the core internal, by at least one spring which opposes the displacement of the casing, and by at least one sensor (23) sensitive to variations in the position of the casing (21), as well as by at least one sensor (23) sensitive to variations in the position of the casing (21), a unit? of programming and command whose entry? connected via signal lines to the handle sensors and whose output? connected on the one hand to the motorized operators of the robot along control lines and, on the other hand, to the memory of the control means of the robot, along lines which supply writing data signals to said memory. 10) Apparatus according to claim 9, with pneumatically controlled motorized operators which can be operated on digitally controllable valves, in which said unit? of programming and command contains analog-digital converters, the command lines coming out of the unit? being connected to the motorized actuating valves. 11. Apparatus according to claim 9, wherein each handle comprises a safety switch, and wherein means are provided for connecting the two safety switches in series. 12) Equipment according to l? claim 9, wherein said handles are detachably fixed to the robot and / or to the tool carried by the robot.