TWI592265B - Safety control method of mechanical arm - Google Patents

Description

Safety control method for robot arm

The present invention relates to a robotic arm, and more particularly to a method of safely controlling a robotic arm.

Most of the robotic arms are used in automation equipment, but in some cases, it is still necessary for the operator to operate the robot arm up close. For example, when the robot arm is in the teaching mode, the operator uses the hand-held teach pendant to fine-tune the robot arm. The position is such that the robot arm operates exactly according to the set trajectory. Even if the robot is in automatic mode, the operator can observe the operation of the robot arm at close range. Since the robot usually works very fast and usually outputs a considerable amount of force, it is necessary to avoid the operator being too close to the robot arm or to avoid the robot arm operating too fast when the operator approaches, so that the operator is not hit by the robot arm. Injured.

In order to make the robot arm safer to use, a conventional method uses a detecting device to plan a working area. When the operator is in the working area, the operating speed of the robot arm is limited to a specific speed (for example, 250 mm/s). In the following, however, this practice still does not ensure the safety of the operator when teaching the robot arm at close range. Another practice is to provide a scanning sensor near the robot arm that detects an operator entering an alarm range and issues an alarm. However, this practice prevents the operator from teaching the robot arm up close. Moreover, in the above two methods, the working area or the scanning range does not change with the operation of the robot arm, so there may still be a safe dead angle, and the safety is still insufficient.

In view of the above-mentioned deficiencies, the main object of the present invention is to provide a safety control method for a robot arm, which can improve the safety of the use of the robot arm.

In order to achieve the above object, the safety control method for the robot arm provided by the present invention comprises the following steps: Mounting a sensing unit to a robot arm and setting at least one control distance to form an imaginary limit range that varies with the operation of the robot arm by the position of the sensing unit and the at least one control distance And b. causing a device under test to move with a user, and detecting, by the signal of the sensing unit and the signal of the device under test, whether the device under test is within the imaginary limit; when the device under test Located within this imaginary limit, the speed of the robot arm is limited.

Since the sensing unit is disposed on the robot arm, when the robot arm operates, the sensing unit and the imaginary limitation range formed by the robot arm move along with the robot arm, and the device under test can be installed on a manual The operation device (such as the teach pendant) of the robot arm is operated or placed on the user so that the device under test moves with the user, so that the problem of a safe dead angle can be avoided, and thus the safety is high.

The sensing unit may include a sensing device or a plurality of sensing devices disposed at different positions, and the step b may detect the distance between the device under test and the sensing devices (ie, the detection distance), and further detect the The device under test approaches the speed of each sensing device (ie, the detection speed). When the detection distance is less than the set control distance, or the detection speed is greater than the predetermined control speed, the operating speed of the robot arm is limited. In addition, the manner in which the speed of the robot arm is limited in the step b can stop the robot arm, or the operating speed of the robot arm can be limited to a predetermined limit speed. When the detection distance is less than a predetermined smaller control distance, or the detection speed is greater than a predetermined larger control speed, the operating speed of the robot arm can be restricted again, which can further improve the user's close proximity to the robot arm. Safety when teaching.

The detailed construction, features, assembly or use of the safety control method for the robot arm provided by the present invention will be described in the detailed description of the subsequent embodiments. However, it should be understood by those of ordinary skill in the art that the present invention is not limited by the scope of the invention.

10‧‧‧Sensor unit

12‧‧‧Sensing device

20‧‧‧ Robotic arm

30‧‧‧ imaginary limits

31‧‧‧First imaginary range

32‧‧‧second hypothetical range

40‧‧‧Device under test

50‧‧‧Operator

60‧‧‧ Controller

70‧‧‧Sensor unit

71‧‧‧First sensing device

72‧‧‧Second sensing device

D‧‧‧Control distance

D1‧‧‧First control distance

D2‧‧‧Second control distance

D3‧‧‧Great control distance

D4‧‧‧Small control distance

d‧‧‧Detection distance

D1‧‧‧first detection distance

D2‧‧‧second detection distance

1 is a safety control method for a robot arm according to a first preferred embodiment of the present invention FIG. 2 is a perspective view of a mechanical arm system provided by the first preferred embodiment of the present invention; FIG. 3 and FIG. 4 are similar to FIG. 1 except that part of the flow is different; 5 is a perspective view of a mechanical arm system according to a second preferred embodiment of the present invention; FIG. 6 is a perspective view of a mechanical arm system according to a third preferred embodiment of the present invention; A flowchart of a safety control method for a robot arm provided by the third preferred embodiment of the present invention; and FIG. 8 is similar to FIG. 2, but shows the robot arm system.

The Applicant first describes the same or similar elements or structural features thereof in the embodiments and the drawings which will be described below.

Referring to FIG. 1 and FIG. 2, a safety control method for a robot arm according to a first preferred embodiment of the present invention includes the following steps:

Mounting a sensing unit 10 to a robot arm 20 and setting at least one control distance D to form a movement with the robot arm 20 by the position of the sensing unit 10 and the at least one control distance D The imaginary limit of change is 30.

In the present embodiment, the sensing unit 10 includes only one sensing device 12, and this step a only sets a control distance D of the sensing device 12, and the imaginary limiting range 30 is the ball with the sensing device 12. The sphere and the control distance D are spherical imaginary ranges of the radius.

b. Detecting a device under test 40 as a user moves, and detecting whether the device under test 40 is located within the imaginary limit range 30 by the signal of the sensing unit 10 and the signal of the device under test 40; The device under test 40 is located within the imaginary limit range 30, thereby limiting the operating speed of the robot arm 20.

In this embodiment, the device under test 40 is mounted on a device for manual operation. An operating device 50 of the robot arm 20, which can be a teach pendant or a hand-held actuating switch; thereby, when a user (such as an operator) holds the operating device 50 to manually operate the robot arm 20 at any time The device under test 40 moves with the user. Alternatively, the device under test 40 may be disposed on the user's clothing or on the safety accessory worn by the user, and thus may move with the user.

The sensing device 12 and the device under test 40 are arranged to detect a detection distance d, that is, the distance between the sensing device 12 and the device under test 40, in order to determine the detection distance d. As a basis for judging the distance between the user and the robot arm 20. The sensing device 12 can be a non-directional wireless signal receiver (such as an RFID reader), and the device under test 40 can be a wireless signal transmitter (such as an RFID tag), and the sensing device 12 receives the received signal. The signal of the measuring device 40 generates a signal corresponding to the detection distance d, and then transmits the signal to a controller 60 for automatically controlling the robot arm 20, so that the controller 60 senses the detection distance d. When the detection distance d is smaller than the control distance D, it indicates that the device under test 40 is located within the imaginary limit range 30, and the controller 60 limits the operating speed of the robot arm 20. The manner of limiting the operating speed of the robot arm 20 in this step b can stop the robot arm 20 from operating or limit the operating speed of the robot arm 20 to a predetermined limit speed to avoid the user being too close to the The robot arm 20 is in danger.

As shown in FIG. 3, the step b can detect a detection speed by calculating a change of the detection distance d with time, and the detection speed is a speed at which the device under test 40 approaches the sensing device 12. When the detection distance d is less than the control distance D, or the detection speed is greater than a predetermined one of the control speeds, the controller 60 limits the operating speed of the robot arm 20, even if the robot arm 20 stops operating or the robot arm 20 The operating speed is limited below a predetermined limit speed to avoid danger by the user being too close to the robot arm 20 or approaching the robot arm 20 too quickly. Alternatively, as shown in FIG. 4, the step b may limit the operating speed of the robot arm 20 when the detection distance d is less than the control distance D and the detection speed is greater than the control speed.

Since the sensing unit 10 is disposed on the robot arm 20, when the robot arm 20 is operated, the sensing unit 10 moves with the robot arm 20, more specifically, the center position of the imaginary restriction range 30 As the posture of the robot arm 20 changes, the imaginary limit range 30 continues to be covered in a more dangerous area, so that the problem of a safe dead angle can be avoided, so The safety control method of the robot arm provided by the invention has high safety.

In order to more effectively prevent the user from being hit by the robot arm 20, a plurality of sensing devices can be mounted on the robot arm 20, such as the robot arm system provided in a second preferred embodiment of the present invention shown in FIG. The second sensing device is mounted on the robot arm 20 to further improve the safety of the robot arm 20. The difference between the embodiment and the first preferred embodiment described above is described in detail below.

In the step a of the embodiment, a sensing unit 70 is mounted on the robot arm 20, and the sensing unit 70 includes a first sensing device 71 and a second sensing disposed at different positions of the robot arm 20. The device 72, the control distance set in the step a includes a pair of first control distances D1 that should be the first sensing device 71, and a pair of second control distances D2 that should be the second sensing device 72. Therefore, the imaginary limit range 30 of the embodiment is a combination of a first imaginary range 31 and a second imaginary range 32, wherein the first imaginary range 31 is the center of the first sensing device 71 and The first control distance D1 is a spherical imaginary range of a radius, and the second imaginary range 32 is a spherical imaginary range in which the second sensing device 72 is a spherical center and the second control distance D2 is a radius, when the robot arm 20 When operating and changing its posture, the size and position of the imaginary limit range 30 will change accordingly.

In the step b of the embodiment, a first detection distance d1 and a second detection distance d2 are detected by the signals of the two sensing devices 71 and 72 and the signal of the device under test 40. The first detection distance d1 is The distance between the first sensing device 71 and the device under test 40 is the distance between the second sensing device 72 and the device under test 40. When the first detection distance d1 is less than the first control distance D1, or the second detection distance d2 is less than the second control distance D2, the controller 60 limits the operating speed of the robot arm 20, even if the robot arm 20 The operation is stopped or the operating speed of the robot arm 20 is limited to a predetermined limit speed. In other words, regardless of whether the device under test 40 is close to the first sensing device 71 or the second sensing device 72, the robot arm 20 is limited in its operating speed, so that the safety of the user can be further ensured.

The step b of the present embodiment can also be used as a condition for limiting the operating speed of the robot arm 20 by the speed of the device under test 40, which is the first sensing device 71 and the first The second sensing device 72 can respectively correspond to a predetermined one of the first control speed and the second control speed, and the step b further detects a first detection speed and a second detection speed, where the first detection speed is the device under test 40 is close to the speed of the first sensing device 71, the second detecting speed The speed at which the device under test 40 approaches the second sensing device 72. When the first detection speed is greater than the first control speed or the second detection speed is greater than the second control speed, the controller 60 limits the operating speed of the robot arm 20, even if the robot arm 20 stops operating or The operating speed of the robot arm 20 is limited to a predetermined limit speed.

As shown in FIGS. 6 and 7 in a third preferred embodiment of the present invention, the same sensing device may also correspond to a plurality of control distances to limit the segmentation according to the degree to which the user approaches the robot arm 20. The operating speed of the robot arm 20. In the third preferred embodiment, the sensing device 12 corresponds to a larger control distance D3 and a smaller control distance D4. When the detection distance d is smaller than the larger control distance D3, the controller 60 limits the mechanism. The operating speed of the arm 20 is also limited to the operating speed of the robot arm 20 below a predetermined larger limiting speed; when the detecting distance d is less than the smaller control distance D4, the controller 60 limits the robot arm again. The operating speed of 20 is also such that the mechanical arm 20 is stopped or the operating speed of the robot arm 20 is limited to a predetermined lower limit speed.

In this way, when the robot arm 20 is in the teaching mode, and the user holds the operating device 50 to teach in the vicinity of the robot arm 20, the operating speed of the robot arm 20 is initially reduced to not exceed the greater control speed. When the user needs to control the robot arm 20 more precisely, and thus closer to the robot arm 20 to confirm its positioning, the operating speed of the robot arm 20 will be reduced again to not exceed the smaller control speed, or stop working. To ensure the safety of users. Similarly, when the robot arm 20 is in the automatic mode, if the user approaches the robot arm 20, the robot arm 20 will also be initially decelerated. If the user is closer to the robot arm 20, the robot arm 20 will be decelerated again, even Emergency stop to ensure the safety of the user.

In addition, the step b can also utilize a predetermined one of the smaller control speeds and a larger control speed as conditions for limiting the operating speed of the robot arm 20, that is, when the device under test 40 approaches the sensing device 12 When the speed (detection speed) is greater than the smaller control speed, the controller 60 limits the operating speed of the robot arm 20 to a predetermined one of a larger limit speed; when the detection speed is greater than the larger control speed, the control The device 60 limits the operating speed of the robot arm 20 to a predetermined lower limit speed or stops the robot arm 20 from operating.

When there are multiple mechanical arm systems operating in the vicinity of each other, for example, there are two mechanical arm systems as shown in FIG. 2 in FIG. 8, and in this case, the sensing unit 10 mounted on each robot arm 20 can also be sensed. Measuring the device 40 of the other robotic arm system to ensure that The safety of the user of the robotic arm system.

Finally, it is to be noted that the constituent elements disclosed in the foregoing embodiments are merely illustrative and are not intended to limit the scope of the present invention, and alternative or variations of other equivalent elements should also be the scope of the patent application of the present application. Covered.

10‧‧‧Sensor unit

12‧‧‧Sensing device

20‧‧‧ Robotic arm

30‧‧‧ imaginary limits

40‧‧‧Device under test

50‧‧‧Operator

60‧‧‧ Controller

D‧‧‧Control distance

d‧‧‧Detection distance

Claims (5)

A safety control method for a robot arm includes the following steps: a. mounting a sensing unit to a robot arm and setting at least one control distance to form a position of the sensing unit and the at least one control distance a hypothetical limit range that varies with the operation of the robot arm; and b. causes a device under test to move with a user, and detects the device under test by the signal of the sensing unit and the signal of the device under test Whether it is located within the imaginary limit; when the device under test is within the imaginary limit, the operating speed of the robot arm is limited; the sensing unit includes a first sensing device and a second sensing device, the at least a control distance includes a first control distance corresponding to the first sensing device and a second control distance corresponding to the second sensing device; a first detection distance and a second detection distance are detected in the step b, The first detection distance is a distance between the first sensing device and the device under test, and the second detection distance is a distance between the second sensing device and the device under test; when the first detection is When controlled from less than the first distance or the second distance is less than the detection distance of the second control, the operating speed of the robot is restricted. The method for safety control of a robot arm according to claim 1, wherein the first sensing device and the second sensing device respectively correspond to a predetermined one of a first control speed and a second control speed, the step b Further detecting a first detection speed and a second detection speed, wherein the first detection speed is a speed at which the device under test approaches the first sensing device, and the second detection speed is a proximity of the device under test to the second sense Measuring device speed; when the first detection speed is greater than the first When a control speed or the second detection speed is greater than the second control speed, the operating speed of the robot arm is limited. A safety control method for a robot arm includes the following steps: a. mounting a sensing unit to a robot arm and setting at least one control distance to form a position of the sensing unit and the at least one control distance a hypothetical limit range that varies with the operation of the robot arm; and b. causes a device under test to move with a user, and detects the device under test by the signal of the sensing unit and the signal of the device under test Whether it is within the imaginary limit; when the device under test is within the imaginary limit, the operating speed of the robot arm is limited; the sensing unit includes a sensing device, and the at least one control distance includes a corresponding sensing One of the devices has a larger control distance and a smaller control distance; in the step b, a detection distance is detected, the detection distance is a distance between the sensing device and the device under test; when the detection distance is smaller than the larger control distance The operating speed of the robot arm is limited, and when the detecting distance is less than the smaller control distance, the operating speed of the robot arm is again restricted. The method for safety control of a robot arm according to claim 3, wherein in the step b, a detection speed is detected, the detection speed is a speed at which the device under test approaches the sensing device; when the detection speed is greater than When one of the smaller control speeds is scheduled, the operating speed of the robot arm is limited, and when the detection speed is greater than a predetermined one of the larger control speeds, the operating speed of the robot arm is again restricted. The method for controlling the safety of the robot arm according to claim 3, wherein the method for limiting the operating speed of the robot arm in the step b is The operating speed of the robot arm is limited to a predetermined one of the larger limiting speeds; the manner of limiting the operating speed of the robot arm in the step b is to stop the mechanical arm or limit the operating speed of the robot arm to a predetermined speed. One is below the lower limit speed.