JPS5848317B2 - How to check the safety of industrial robots - Google Patents

Description

[Detailed description of the invention] The present invention relates to a safety confirmation method for industrial robots.

Industrial robots have been put into practical use in response to demands for labor-saving, rationalization of work, etc. due to rising labor costs, and are proving to be very effective.

Particularly in machine factories where a large number of machine tools are installed, having industrial robots perform simple services such as replacing workpieces and tools for each machine tool has achieved remarkable effects, and the demand for this is increasing every year. It is increasing year by year.

FIG. 1 shows an example of such an industrial robot, with FIG. 1A being a plan view and FIG. 1B being a side view.

Among them, 1 is a mechanical hand that grips the workpieces when exchanging them, 2 is a wrist that can rotate and swing up and down, 3 is an extendable arm, 4 is a casing that can move up and down and rotate about the axis Y, 5 is a frame, 6 is a teaching operation panel for teaching robot movements, 7 is an operation panel for operator operation, 8
It sequentially memorizes teaching contents based on instructions from the teaching operation panel 6, such as operation position (point), operation speed, type of service, etc., and operates the mechanical hand 1, wrist 2, arm 3, and casing 4 according to the teaching contents. This is the control unit that carries out the operation.

Now, in such a playback type industrial robot,
In advance, teach the service operation from the teaching operation panel 6,
The teaching contents (hereinafter referred to as robot command data) are stored in the memory in the crawler leg 8, and each time there is a service request from the machine side, a series of robot command data is sequentially read out and service is repeatedly provided to the machine. .

This robot command data consists of service codes that instruct the point information to be serviced, the operating speed, the arm of the hand at the point, the exchange of signals with the machine tool, and the like.

In addition, the above teaching generally includes (l) setting of a memory address where robot command data is to be stored, (2) jog feeding (
(3) Setting the point position information and speed command value, (4) Setting the robot service code. By repeating the sequence of (1) to (4) above, the work is completed. A series of robot movements are taught to the machine.

Therefore, unless there is any failure in the control system or mechanism of the robot, the robot will correctly replace the workpiece and remove chips after completing positioning at the predetermined operating speed in accordance with the robot command data each time a service request is made. , tool exchange, hand control, and other services are executed one after another.

By the way, in a system consisting of such a machine tool and a robot, damage to the mechanical parts has conventionally occurred due to mutual interference between the machines.

This is because, even if an obstacle is placed in the machine tool or robot operating area after the above teaching, or the relative positioning of the machine tool and robot is changed for some reason, etc. This is because the robot may be moved according to the previous teaching without changing the teaching contents.

In such a case, the movable part of the robot will collide with an obstacle or machine tool and be damaged.

Furthermore, there are cases where a failure occurs in the control system, causing the robot to run out of control, and in such cases, mechanical parts may be damaged due to collision between the robot and the machine tool.

As described above, the conventional system has the disadvantage that not only mechanical parts may be damaged, but also safety measures for workers are not considered.

This is because a worker may accidentally intrude into the operating area of a machine tool or a robot, but conventional systems have no countermeasures against such situations.

The present invention aims to improve the above-mentioned conventional drawbacks and to provide a new safety confirmation method that can prevent damage to mechanical parts and danger to workers.

In order to achieve the above-mentioned objects of the present invention, the present invention provides for attaching a plurality of tactile sensors to either or both of an industrial robot and a machine serviced by the robot, and operating the robot according to a predetermined operation sequence. When the tactile sensor is operated, it is determined whether the detection output of the tactile sensor at a predetermined time is in an acceptable state that has been stored or set in advance, and if it is not in the acceptable state, the industrial robot or A method for confirming the safety of an industrial robot is provided, which is characterized by stopping the operation of one or both of the machines.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a schematic diagram showing an embodiment of the present invention, in which 10 is a numerical control device that supports a machine tool, 11 is a machine tool, 12 is a robot that services the machine tool 11, and 81
-S5 are tactile sensors such as pressure-sensitive switches and microswitches; among these, tactile sensors S1 to S3 are installed at appropriate locations on movable parts of the robot, such as mechanical hands, and tactile sensors S4 to S5 are installed at appropriate locations on the machine tool 11. mounted on.

Note that these plurality of tactile sensors may be attached to an appropriate location on either the machine tool 11 or the robot 12.

FIG. 3 is a block diagram showing a circuit for realizing the safety confirmation method according to the present invention, where 1 to I5 are inverter FF. ~FF, is a flip-flop that is reset at the time of initialization, and is set and reset by the output of each antenna sensor S1~S, AG1~AG3 are AND gates, and TIM counts the time from the start of service, for example, a predetermined time. The timer, WR, which outputs a signal every time, is in the permissible state setting mode, and each time a signal is generated from the timer TIM, a writing circuit writes the content of the output of each tactile sensor S0 to S as a permissible state to the memo IJ MEM; The MEM outputs the output of each antenna sensor at times t1, t2...tn...
As shown in Fig. 4, the memory for storing data in chronological order, RD, is being serviced by the robot at time 11, 1.
2...tn...... A continuation circuit that reads out the memory contents corresponding to that time every time, RG is a register that temporarily stores the contents read out by RD, and COM is a register for each flip. This comparison circuit compares the contents of flops FF1 to FF5 with the contents of register RG and outputs a mismatch signal NE when the contents differ.

Next, the operation of the above circuit will be explained.

After teaching, when the mode is set to allowable state, the signal PM
S becomes 'l''.

On the other hand, when the robot 12 starts servicing the machine tool 11 according to the teaching content, the service starting signal SS
becomes ``l''.

When the signal SS becomes '1', the timer TIM starts counting the time, and when time t0 elapses, it outputs the signal TS.

This signal TS opens the AND gate AG1, and the write circuit WR writes the detection outputs of the touch sensors S1 to S5 at the time t1 to the address AD of the memory MEM.

From then on, Kuima TIM will change to time 11, 12...tn
Every time . . . is detected, the signal TS becomes 1l",
The detection outputs of the tactile sensor at these times are sequentially stored in addresses AD2, AD3, . . . ADn, .

Note that at this time, since the signal PMS indicating that the permissible state is being set is being applied to the comparison circuit COM, the comparison circuit has stopped the comparison operation.

As described above, in the embodiment shown in FIG. 3, predetermined times 11, 12-...tn...
Although the tactile sensor detection outputs in ... are stored in the memory in chronological order as permissible states, they may be stored in the memory simultaneously at the time of teaching.

Now, once the storage operation of the permissible state in the memory is completed, the safety confirmation operation according to the present invention can be performed thereafter.

Next, this safety confirmation operation will be explained.

When the service by the robot is started, the service start signal SS becomes 1l", the timer TIM starts counting time, and the times t1, t2...trr...
The timer outputs the signal TM, and the output of the AND gate AG2 becomes '1'.

Therefore, the readout circuit RD operates at each of these times t1, t2...
. . . Memo IJMEM address AD1, AD2.
. . . The contents are read out and stored in register RG.

On the other hand, the output of each tactile sensor S1 to S5 attached to the machine tool or robot is from the flip-flop FF1.
~FF, respectively, and their momentary states are stored in the flipflop group.

On the other hand, the output of the flip-flop and the contents of the register are each manually inputted to a comparison circuit COM, where they are compared at each time t1, t2, . . . .

Therefore, if the tactile sensor detection output does not match the contents of the register due to the mutual arrangement of the machines being different or the robot running out of control, the mismatch signal NE is immediately output.

The discrepancy signal NE is outputted as an emergency stop signal via the AND gate AG3, and the operation of one or both of the machine tool and the robot is immediately stopped.

In the figure, NGS is a signal for ignoring the safety confirmation function according to the present invention.

Furthermore, even if the robot is operating correctly,
If a worker enters the machine tool operating area or the robot robot operating area and touches the tactile sensor, an emergency stop signal is immediately output and the robot and/or the machine The machine will come to an emergency stop, preventing danger to workers.

Although the present invention has been described above according to the above embodiments, the present invention is not limited to these examples and can be modified in various ways.

For example, although the permissible state is stored in the memory, it may also be set in a switch or the like.

In addition, although we have explained the case where the output of the tactile sensor is automatically read and stored in the memory, if the permissible state at each time is known, it may be configured to be input manually from, for example, a teaching operation panel. It's okay.

Furthermore, the memory storage contents can be configured so that they can be manually modified as appropriate.

As described in detail above, according to the present invention, it is possible to prevent damage to mechanical parts due to mutual interference between machines, and to improve the safety of workers, which has a significant effect.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the external appearance of an industrial robot, Fig. 2 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 3 is a block diagram showing an embodiment of the invention, and Fig. 4 is FIG. 2 is an explanatory diagram illustrating the storage state of a memory. In the figure, 1 is a mechanical hand, 2 is a wrist, 3 is an arm, 4 is a casing, 5 is a frame, 6 is a teaching operation panel, 7 is an operation panel, 8 is a control unit, 10 is a numerical control device, and 11 is a machine tool , 12 is the robot, Y is the axis, S1 to S5 are antenna sensors, I1 to I5 are inverters, AG1 to AG3 are AND gates, TIM is a timer, MEM is a memory, WR is a write circuit, RD is a read circuit, and COM is a The comparator, RG, is a register.

Claims (1)

[Scope of Claims] 1. When a plurality of tactile sensors are attached to either or both of an industrial robot or a machine serviced by the robot, and the robot is operated according to a predetermined operation sequence, the predetermined number of tactile sensors is Determine whether or not the detected output at the time is in an acceptable state that has been stored or set in advance, and if it is not in the acceptable state, operate either or both of the industrial robot or machine. A method for confirming the safety of an industrial robot, which is characterized by stopping the robot. 2. The method for confirming the safety of an industrial robot according to claim 1, wherein the detected outputs of each of the tactile sensors during normal operation of the industrial robot are stored as an acceptable state. 3. A patent characterized in that permissible states at a number of points in time are stored in advance, and it is sequentially determined whether the detection output of the tactile sensor at the time corresponding to each of these points is in the permissible state. A method for confirming the safety of an industrial robot according to claim 1 or 2. 4. Claims characterized in that the industrial robot is a playback type industrial robot, and when teaching robot motion to the robot, each tactile sensor output at each of the predetermined times is stored as an allowable state. 1st
A method for confirming the safety of an industrial robot as described in Section 3 or Section 3.