JPS6336918B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot that appropriately controls the position of a moving member that supports an operating element. Generally, commercially available industrial robots include cylindrical coordinate type, rectangular coordinate type, reference coordinate type, and articulated type robots. In order to reduce the unit price of these industrial robots, so-called standard specification robots are mass-produced in which the maximum movement strokes, ie, the maximum operating ranges, of various moving members are appropriately selected. On the other hand, during use, it is unlikely that the entire maximum operating range of a robot with the above-mentioned standard specifications is effectively used, and in most cases, the operating range is limited to a certain operating range within the above-mentioned maximum operating range. There are many things. Moreover, the operating range specified during use is approximately determined by the size of the actuated object, that is, the workpiece, and the robot may be operated by frequently replacing workpieces of different sizes. By the way, in industrial robots, the robot is operated by operating a microcomputer based on numerical data or input data through a so-called teaching operation, or the robot is operated by a fixed electrical sequence control device. Conventionally, the operating range of a robot has only been electrically selected. For example, Figures 1 and 2
As shown in the figure, the angle at which the rotating member of the robot, that is, the movable member 1, can rotate in the _Θ1 direction or the _Θ2 direction with respect to the _Y1 - _Y2 line is indicated by α+Δα, and the movable member 1 When the maximum operating range that can be repeatedly operated is indicated by an angle of 2α, in order to select the operating range of the movable member 1 at an angle of α ₁ + α ₂ , for example, rotational drive for rotating the moving member 1 is required. Machine 1
0 electrically limit the total number of pulses in the Θ ₁ and Θ ₂ directions to correspond to _the angles α ₁ and _{α 2} , or
The rotation speed in relation to the direction is detected by a rotation detector, and the input data is such that the drive of the rotary drive machine is stopped when this detection signal, for example, the number of detection pulses of an encoder, reaches a value corresponding to the angle: α ₁ and α ₂ . At present, it has been limited to electrically limiting the amount of electricity.
By the way, in an industrial robot, if various cables are broken or the original position returns to an abnormal position due to an unexpected cause, the movable member 1 may overrun or run out of control beyond the operating range in the Θ ₁ direction or Θ ₂ direction. , whereby the operating element 7 supported by the movable member should be inherently safe, that is, the safe area: the area B 1 and A ₅ to A ₅ surrounded by A ₁ to A ₄ .
It invades the area B ₂ surrounded by A ₈ . Therefore, in the above case, when a worker was in the supposed safe area B ₁ or B ₂ or when other equipment was being installed, the operating elements and their supporting members could be used to protect the worker or the equipment. This may cause personal injury or damage to equipment or parts of the robot. When the robot is operating normally like this,
Areas B ₁ and B ₂ are safe areas, but
If the robot operated abnormally due to an unexpected cause, areas _B1 and _B2 could no longer be considered safe areas. In particular, the occurrence of a personal injury accident is the worst situation for a worker, and for this reason, the robot's maximum operating range has to be regarded as a dangerous range in case of an emergency. Therefore, even though the actual operating area is relatively small, a large installation area must be secured in order to operate the robot safely, making it impossible to use the factory site effectively.

An object of the present invention is to provide an industrial robot that eliminates the above-mentioned conventional drawbacks.

The present invention will be explained in detail below with reference to the illustrated embodiments. Now, to describe the multi-joint arm type industrial robot, 1 is a movable member supported so as to be freely pivotable in the horizontal direction relative to the fixed member 2, and 3 and 4 are each rotatably supported relative to the movable member 1. A lower arm and a link lever, 5 is a rear arm rotatably supported by the link lever 4, 6 is an upper arm rotatably supported by the lower arm 3 and the rear arm 5, respectively;
The lower arm 3, link lever 4, and rear arm 5 form a parallel link mechanism. At the end of the upper arm 6 an operating element 7, for example a welding torch, is supported directly or via a suitable drive mechanism. 8 and 9 are first and second rotary drive machines supported by the moving member 1, the lower arm 3 is vertically rotated by the first rotary drive machine 8 via a reducer, and the upper arm 6 is rotated by the first rotary drive machine 8 via a reducer. The lower arm 3 and the upper arm 6 are pivoted in the vertical direction via the link lever 4 and the rear arm 5, which are rotated by the second rotary drive machine 9. Further, the moving member 1 is rotated in the horizontal direction by a third rotary drive machine 10 via a speed reducer.

By the way, as shown in FIG. 2, the moving member 1
The maximum turning angle that can be operated by repeating is set to 2α,
The maximum angle of use of the moving member 1 that is actually used is α ₁ +
Let α be ₂ . In FIG. 3, for example, 11 and 1
Reference numeral 2 denotes first and second abutting members L 1 to L ₂ which are fastened to the movable member 1 so that their positions can be freely set in the circumferential direction.
Ln and R1 _to Rn are, for example, first detectors suitably arranged on the movable member 1, and are constituted by, for example, a plurality of proximity switches. 13 is, for example, a stopper fixedly fastened to the fixed member 2;
and 15 are, for example, a second detector disposed near the stopper 13 to detect the positions of the contact members 11, 12, and are, for example, a limit switch. In the state shown in FIG. 3, by tightening the first and second contact members 11 and 12 to the movable member 1, for example,
R ₄ and L ₃ detectors are activated. The maximum turning angles of the moving member 1 in the Θ ₁ direction and Θ ₂ direction in this state are β ₁ and β ₂ , and when the moving member 1 turns by the angles; β ₁ and β ₂ , the first or second The abutting members 11 or 12 are respectively stoppers 13
comes into contact with. Note that the second detectors 14 and 15 detect detection signals at a position slightly before the position where the contact members 11 and 12 contact the stopper 13, and at a position where the movable member 1 exceeds the angles α ₁ and α ₂ . is arranged so that it occurs. That is, the relationships β ₁ >α ₁ and β ₂ >α ₂ hold.

Generally, industrial robots operate based on electrical command signals, but in the above-mentioned robots, the electrical command signals are actually activated in response to the detection signal of the first detector set at an appropriate position. The maximum permissible value of the electrical command signal input to the robot's drive system is limited. That is, for example, when the abutting members 11 _{and 12} are set at the positions shown in FIG. The maximum permissible value of the electrical command signal taken into the drive system is electrically selected so that the maximum usable angles in _{the 1} direction and the Θ ₂ direction are, for example, α ₁ and α ₂ .

In the above, when the robot is operating normally, the working area of the robot is areas _B3 and _B4 limited by the angle _α1 + _α2 . Moreover, during work, the reason why the contact members 11 and 12 are set in the state shown in FIG. 3 is to limit the working area of the robot to the area shown by the angle α ₁ + α ₂ . , in this case, the moving member 1
Even if input data is input that generates an electrical command signal to move the angle by an angle of α ₁ + α ₂ or more, the detection signal of the first detector when the abutment members 11 and 12 are set in position will cause The moving member 1 does not move beyond a predetermined angle of use; α ₁ +α ₂ .

By the way, when an abnormal situation occurs due to an unexpected cause, the robot may turn in the _Θ1 direction or _Θ2 direction beyond the above-mentioned operating areas _B3 and _B4 .
For example, when the robot turns in the _Θ1 direction and the turning angle becomes _β1 , the first contact member 11 comes into contact with the stopper 13, so the movable member 1 is mechanically restrained and thereafter rotates in the _Θ1 direction. It does not turn around.
Similarly, in the Θ ₂ direction, if the movable member 1 rotates by an angle β ₂ from the reference position indicated by the line Y ₁ -Y ₂ , the moving member 1 will not rotate in the Θ ₂ direction thereafter. By the way, in these cases, at a position slightly before the position where the contact members 11 and 12 contact the stopper 13,
Alternatively, the second detectors 14 and 15 are activated at a position where the movable member 1 exceeds the angle α ₁ or α ₂ , and the abnormal state is detected by this detection signal, and the abnormal state is notified to the operator by, for example, an alarm means. At the same time, the robot control power is turned off by appropriate control means to stop various drives. In this case, the rotating moving member has inertia due to the weight of the moving member and each part mounted on the moving member, so even if the rotary drive machine is de-energized, it will not stop immediately. . In this case, even if the movable member turns further due to inertia, the abutment members 11 and 12 abut against the stopper 13, so that the movable member is reliably stopped. In this way, the second detector 14,
15, the robot control power is turned off, and the detector is not constantly activated.

When an abnormal situation occurs due to an unexpected cause as described above, the robot turns beyond the predetermined operating range, but the turning range of the moving member is limited by a mechanical position restraint mechanism consisting of a contact member and a stopper. Moreover, an abnormal situation can be reliably known from the detection signal of the second detector.

FIG. 4 is a diagram showing another embodiment of the first detector of the present invention, for example, the conductive members 16, 17.
Electricity is applied between the ends of the detector 1 and the contact members 11 and 12, and the detector
The permissible movement value of the moving member 1 is limited based on the current values detected at 8 and 19.

By the way, when the positions of the contact members 11 and 12 are kept unchanged, that is, as shown by the two-dot chain line in FIG. 3, the moving member and the contact member are fixed, and two stoppers are provided on the fixed member side. When provided, the operating range of the robot can be appropriately selected by setting these two stoppers at appropriate positions. In this case, if the first detector is disposed on the fixed member side, each stopper and the first
The position of each stopper may be appropriately set while the arrangement with the detector remains unchanged. Of course,
If the first detector is disposed near the movable abutment member, it is only necessary to appropriately set the positions of the respective stoppers. Furthermore, it is also possible to leave the abutment member and stopper that define the maximum movable area of the robot as they are, and to create and install a new abutment member or stopper that is disposed in a variable setting position. Further, the second detector is disposed on the side of the abutting member that is fixed to the moving member, the side of the abutting member that is disposed in a variable position with respect to the moving member, or the side of a stopper that is disposed as a variable position with respect to the moving member. You can also. Furthermore, the first and second detectors may be any type of limit switch, proximity switch, photoelectric switch, or the like. Note that if the stopper and the second detector are fixed to the fixed member, the first detector is arranged to the movable member, and the abutting member is set to be variable in position with respect to the movable member, the movable member, That is, when changing the operating range of the robot, it is only necessary to change the set position of the abutment member, and therefore the control cables of the first and second detectors remain unchanged.
The occurrence of disconnection accidents is minimized compared to when the control cables are relocated. Also the second
If a detector is provided, the rotary drive machine can be put into a non-driving state in the event of an abnormal condition, so the rotary drive machine can be used for a long life without being overloaded. By activating the alarm means based on the detection signal of the second detector, the abnormal state can be detected early and reliably, but the provision of the second detector can nevertheless be omitted. Furthermore, a cutting tool, a paint spray gun, a gripping tool, an assembly tool, etc. can be appropriately selected as operating elements. Furthermore, industrial robots such as multi-joint type, cylindrical coordinate type, and polar coordinate type include swinging movements in the horizontal direction or vertical direction, but the operating speed of the tip part that makes such a swinging action is compared to the rotating base part. When this type of robot goes out of control, it instantly reaches the end of its maximum operating range, so it is impossible to avoid the rotating tip, and the inertia of the tip is large. Therefore, if a worker is hit by this tip member, there is a very high probability that the worker will be fatally injured.For this reason, the present invention is particularly effective for industrial robots having rotating movable members. Of course, it can also be applied to robots using Cartesian coordinates. Further, an appropriate shock absorber may be provided to weaken or eliminate the shock when the abutting member and the stopper abut.

As described above, according to the present invention, the stopper and the abutting member that can come into contact with each other are arranged relative to the movable member and the fixed member, and the operating element is applied to the movable member whose operation area is restricted in both moving directions. In an industrial robot that supports and controls the position of the movable member, the stopper or the abutting member is disposed at a variable tightening setting position so that the set contact interval between the stopper and the abutting member is variable. A position detection signal corresponding to the set tightening position of the stopper or the contact member is output, and in response to the position detection signal, the operating range of the movable member, whose operating range is until the stopper and the contact member come into contact, is electrically controlled. By arranging a detector for setting the industrial robot, the operating range of the industrial robot is limited in response to the detection signal of the first detector, so if a command signal that exceeds the operating range is accidentally sent Even if this occurs, the robot will not move beyond the predetermined operating range, and if the robot operates abnormally, the moving member will be restrained by a mechanical position restraint mechanism and the swing operating range will be limited. The area other than this swing operation area is definitely a safe area, and worker safety is inevitably strictly observed.
Moreover, since various equipment can be placed in this safe area, the factory site can be used effectively, and there is no need to worry about the robot coming into contact with various equipment and damaging various parts of the robot, as in the past. do not have. Furthermore, as mentioned above, if the second detector is provided, when the robot operates abnormally, the abnormal state can be reliably and quickly detected by the detection signal of the second detector, and the moving member can be quickly detected. Since the rotary drive machine for turning can be put into a non-driving state, the rotary drive machine will not be overloaded, and there is an advantage that the rotary drive machine can be used for a long time.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of an industrial robot to which the present invention is applied, FIG. 2 is a plan view of FIG. FIG. 4 is a diagram showing a modification of the main part of the present invention. DESCRIPTION OF SYMBOLS 1... Moving member, 2... Fixed member, 7... Operating element, 10... Rotating drive machine, 11, 12... Contact member, 13... Stopper, _L1 ~Ln, _R1 ~Rn...
...first detector, 14,15...second detector.

Claims (1)

[Claims] 1. A first member 1 and a second member 2 that are connected so as to be relatively movable, a drive machine 10 that moves the second member 2 relative to the first member 1, and a control device that controls the drive machine 10. , first member 1 or second member 2
a stopper 13 fixed to either one of the
A contact member 11 is fixed to the other of the first member 1 or the second member 2 so as to be able to come into contact with a stopper 13. In an industrial robot regulated by a contact member 11, the fixing position of one or both of the stopper 13 and the contact member 11 is variable, and the fixing position of the stopper 13 or the contact member 11 is variable. A detector R for detecting the fixed position is provided, and the control device inputs the output signal of the detector to prevent the second member from moving outside the relative movable area regulated by the stopper and the abutting member. An industrial robot characterized in that the driving machine is controlled to prohibit movement.