robot systems

Abstract

This system provides a robot system that allows for easy installation of image sensors on various industrial robots and enables high-precision position measurement. [Solution] The robot system 1 includes an industrial robot 10 that performs work in a workspace by operating a robot arm 12, an image sensor 20 that measures the position of an object while the industrial robot 10 is operating, and a sensor base 30 for mounting the image sensor 20, which is provided between the robot arm 12 and the installation surface 2 of the industrial robot 10 in the workspace and remains stationary even while the industrial robot 10 is operating. The image sensor 20 is a fisheye camera or a wide-angle camera. At least four or more image sensors 20 are arranged on the sensor base 30 at intervals in the circumferential direction surrounding the base of the industrial robot 10, and the overlapping portion where the imaging ranges of adjacent image sensors 20 in the circumferential direction overlap is continuous over 360° around the industrial robot 10.

Description

Technical Field

[0001] The present invention relates to a robot system including an industrial robot and an image sensor.

Background Art

[0002] An industrial robot is an industrial machine that performs various operations within a work space by operating a robot arm. Patent Document 1 describes a system that captures an image (video) around the robot by an image sensor during the operation of the industrial robot and uses it for measuring the position of workers around the robot. The measurement results are used for predicting collisions between the industrial robot and the workers, and if necessary, the industrial robot is made to perform an avoidance operation to avoid collisions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The image sensor is generally attached above the industrial robot on the condition that it does not limit the operating range of the robot arm, and is particularly often attached to the ceiling of the work space. However, it takes time and effort to attach the image sensor to the ceiling.

[0005] In addition, the usage environment of industrial robots is diverse, and there are cases where there is no ceiling at an appropriate height in the work space. In such cases, it is necessary to assemble a scaffold or the like for attaching the image sensor within the work space so as not to limit the operating range of the robot arm, and the installation work of the scaffold or the like becomes a large-scale task.

[0006] In addition, there are examples of attaching image sensors to the robot arm of industrial robots, but there are concerns that the accuracy of position measurement by the image sensor will decrease because the image sensor moves along with the movement of the robot arm.

[0007] This invention has been made in view of the above-mentioned problems, and aims to provide a robot system that allows for easy installation of image sensors on various industrial robots and enables high-precision position measurement. [Means for solving the problem]

[0008] The present invention, which solves the aforementioned problems, is a robot system comprising: an industrial robot that performs work in a workspace by operating a robot arm; an image sensor that measures the position of an object while the industrial robot is in operation; and a sensor base for mounting the image sensor, which is provided between the robot arm and the installation surface of the industrial robot in the workspace and remains stationary even while the industrial robot is in operation, wherein the image sensor is a fisheye camera or a wide-angle camera, and at least four of the image sensors are arranged on the sensor base at intervals in the circumferential direction surrounding the base of the industrial robot, and the overlapping portion where the imaging ranges of adjacent image sensors in the circumferential direction overlap is continuous over 360° around the industrial robot.

[0009] The sensor base is, for example, a mounting platform on which the base of the industrial robot is mounted. In some cases, multiple industrial robots may be mounted on a single mounting platform.

[0010] It is also desirable that the image sensor be able to switch between an ON state, where image acquisition is being performed, and an OFF state, where image acquisition is not being performed, individually. [Effects of the Invention]

[0011] The present invention provides a robot system that allows for easy installation of image sensors on various industrial robots and enables highly accurate position measurement. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic plan view illustrating an example of a robot system according to an embodiment of the present invention. [Figure 2] Figure 1 is a perspective view showing a schematic of the robot system. [Figure 3] Figure 1 is a schematic plan view showing the imaging range of one image sensor. [Figure 4] This is a schematic plan view showing the overlapping portion A and non-overlapping portion B of the imaging ranges of adjacent image sensors in Figure 1. [Figure 5] Figure 2 is a perspective view showing a modified sensor-based design. [Figure 6] Figure 2 is a perspective view showing another modified sensor-based design. [Figure 7] This is a schematic plan view illustrating an example where only some of the image sensors are turned on. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described in detail below with reference to the drawings.

[0014] Figure 1 is a schematic plan view showing an example of a robot system 1 according to an embodiment of the present invention. Figure 2 is a schematic perspective view showing the robot system 1 of Figure 1.

[0015] The main components of the robot system 1 consist of an industrial robot 10, an image sensor 20, and a sensor base 30.

[0016] The industrial robot 10 performs various tasks in a workspace such as a factory by operating its robotic arm 12. The industrial robot 10 is installed on the installation surface 2 in the workspace via a frame 4.

[0017] The industrial robot 10 has a base link 11 and a robot arm 12. The base link 11 is a member for supporting the robot arm 12 and is provided at the base of the industrial robot 10. The robot arm 12 is configured by rotatably connecting a plurality of arm members 121. A robot hand (not shown) according to the work content is provided at the tip of the robot arm 12. Note that the "base" refers to the end portion on the opposite side of the tip of the robot arm 12 where the robot hand is provided in the industrial robot 10.

[0018] The operation of the robot arm 12 is controlled by a control device (not shown) of the industrial robot 10. In this embodiment, the industrial robot 10 is a vertically articulated robot, but it is not limited to this. For example, a horizontally articulated robot or the like may be used.

[0019] The image sensor 20 is a sensor that images the surroundings of the industrial robot 10 during the operation of the industrial robot 10 and measures the position of the object. The object to be position-measured is a person, an object, or the like that moves within the work space and may come into contact with the industrial robot 10. From the viewpoint of safety, it is necessary to avoid contact between the object and the industrial robot 10. The control device of the industrial robot 10 causes the industrial robot 10 to perform an avoidance operation for avoiding contact between the object and the industrial robot 10 according to the result of the position measurement of the object.

[0020] The image sensor 20 of this embodiment is a fish-eye camera using a fish-eye lens, and has a main body 21 and a lens unit 22 to form a main part. By using a fish-eye camera as the image sensor 20, a wide-range image (video) can be imaged by one image sensor 20, and the number of image sensors 20 installed for imaging the surroundings of the industrial robot 10 can be reduced. Note that the image sensor 20 may be a wide-angle camera using a wide-angle lens, and the same effect can be obtained by this. The image sensor 20 is communicably connected by wire using a cable (not shown) or the like to the control device of the industrial robot 10. Note that the connection between the image sensor 20 and the control device may be wireless.

[0021] The sensor base 30 is an attachment portion for attaching the image sensor 20, and is provided between the robot arm 12 of the industrial robot 10 and the installation surface 2. The sensor base 30 of the present embodiment is an installation base for installing the industrial robot 10, and the base of the industrial robot 10 is installed on the sensor base 30.

[0022] The sensor base 30 is fixed to the pedestal 4 on the installation surface 2, and is in a stationary state even during the operation of the industrial robot 10 and does not move. Note that the fixing position of the sensor base 30 in the work space is not limited to the pedestal 4. Also, the fixing method of the sensor base 30 is not particularly limited.

[0023] The sensor base 30 of the present embodiment is a rectangular plate-like member having a certain thickness. However, the shape and dimensions of the sensor base 30 are not particularly limited. Also, the material of the sensor base 30 is not particularly limited as long as it has a certain rigidity. For example, steel materials or the like can be used.

[0024] The main body 21 of the image sensor 20 is attached to the upper surface of the sensor base 30. The image sensors 20 are arranged on the sensor base 30 with at least four or more spaced apart in the circumferential direction surrounding the base of the industrial robot 10. In the example of FIG. 1, four image sensors 20 are arranged at the four corners of the upper surface of the sensor base 30, and the distances between adjacent image sensors 20 in the circumferential direction are equal to each other.

[0025] FIG. 3 is a plan view schematically showing the imaging range by one image sensor 20 of FIG. 1. The imaging range by the image sensor 20 is, in a plane, a range of an angle of view θ of about 200° centered on the image sensor 20 outside the image sensor 20. During the operation of the industrial robot 10, this imaging range does not change. Note that "outside" refers to the side away from the base of the industrial robot 10.

[0026] The position measurement of an object by the image sensor 20 is performed by the control device of the industrial robot 10 detecting the presence of a common object from images captured by adjacent image sensors 20 in the circumferential direction and calculating the position of the detected object. The position of the object can be calculated using the positions of the adjacent image sensors 20 and the position of the object in the image captured by each image sensor 20 (i.e., the direction of the object as seen from each image sensor 20), using the conventional triangulation method.

[0027] Therefore, the position measurement of an object can only be performed in the overlapping portion where the imaging ranges of the adjacent image sensors 20 overlap, and cannot be performed in the non-overlapping portions where the imaging ranges do not overlap.

[0028] Figure 4 is a schematic plan view showing the overlapping portion A and non-overlapping portion B of the imaging ranges of the adjacent image sensors 20 in Figure 1. As shown in Figure 4, in this embodiment, the non-overlapping portion B is a portion that protrudes outward in a convex shape from each image sensor 20. If L is the distance from the base of the industrial robot 10 to the outer end of the non-overlapping portion B, then the overlapping portion A is continuous over 360° around the industrial robot 10 in the outer region 3 where the distance from the base of the industrial robot 10 is greater than L. Therefore, in this robot system 1, it is possible to measure the position of an object over 360° around the industrial robot 10.

[0029] In this embodiment, it is assumed that the robot arm 12 stops moving after detecting an object at a predetermined distance from the base of the industrial robot 10, and the minimum distance at which the detected object does not come into contact with the robot arm 12 before it stops is determined. This distance is set considering the movement speed of the object, the movement speed of the robot arm 12 before it stops, and the time from when the object is detected until the robot arm 12 stops moving. The field of view, arrangement, and number of image sensors 20 (four or more) are determined so that the distance L is shorter than the set distance. The distance L is not particularly limited as long as it is shorter than the set distance. For example, it can be the maximum distance that the tip of the robot arm 12 can reach.

[0030] As described above, in this embodiment, a sensor base 30 is fixed between the robot arm 12 of the industrial robot 10 and the mounting surface 2, the base of the industrial robot 10 is mounted on the sensor base 30, and four or more image sensors 20 are installed on the sensor base 30 at intervals in the circumferential direction surrounding the base of the industrial robot 10. The overlapping portion A of the imaging ranges of adjacent image sensors 20 in the circumferential direction is made continuous over a 360° radius around the industrial robot 10.

[0031] This allows for easy installation of the image sensor 20 on various industrial robots 10, enabling high-precision position measurement of objects within a 360° radius around the industrial robot 10. Furthermore, the image sensor 20 does not restrict the operating range of the robot arm 12, nor does the movement of the robot arm 12 reduce the accuracy of position measurement by the image sensor 20.

[0032] Furthermore, since the sensor base 30 in this embodiment is a mounting stand on which the base of the industrial robot 10 is attached, there is no need to modify the industrial robot 10 in order to attach the image sensor 20, making the installation of the image sensor 20 even easier.

[0033] However, the present invention is not limited to the above-described embodiments. For example, the sensor base 30 in this embodiment is a solid rectangular plate-shaped member, but the sensor base 30 may have a cavity inside, and the aforementioned cable can be passed through the cavity.

[0034] Furthermore, although the image sensor 20 is placed on the upper surface of the sensor base 30 in the example shown in Figure 2, the placement of the image sensor 20 on the sensor base 30 is not limited to this.

[0035] Figure 5 is a perspective view showing a modified sensor base 30a of the sensor base 30 in Figure 2. The sensor base 30a is a cylindrical member, and the image sensor 20 is positioned on the side surface of the sensor base 30a. In the example in Figure 5, the main body 21 of the image sensor 20 is embedded in the side surface of the sensor base 30a. Note that the mounting surface 2 and the stand 4 are not shown in Figure 5. This is also the case in Figure 6, which will be described later.

[0036] Furthermore, although the example in Figure 2 shows one industrial robot 10 installed on one sensor base 30, the number of industrial robots 10 installed on the sensor base 30 is not particularly limited.

[0037] Figure 6 is a perspective view showing a sensor base 30b, which is another modified example of the sensor base 30 in Figure 2. The sensor base 30b has a rectangular plane, and multiple industrial robots 10 (two in the example in Figure 6) are installed at intervals along the long side of the sensor base 30b. The field of view, arrangement, and number of image sensors 20 on the sensor base 30b can be determined in the same way as described above.

[0038] In this way, by installing multiple industrial robots 10 on a single sensor base 30b, the image sensor 20 on the sensor base 30b can be shared among multiple industrial robots 10, reducing the number of image sensors 20 per industrial robot 10.

[0039] Furthermore, although the sensor base 30 in this embodiment is a mounting base for the base of the industrial robot 10, it is not particularly limited as long as it is positioned between the robot arm 12 of the industrial robot 10 and the mounting surface 2 and remains stationary even while the industrial robot 10 is in operation. For example, the base link 11 (see Figure 2) of the base of the industrial robot 10 does not move and remains stationary while the industrial robot 10 is in operation, so the base link 11 may be used as the sensor base and the image sensor 20 may be attached to the side surface of the base link 11.

[0040] Furthermore, depending on the operating environment of the industrial robot 10, there may be cases where it is not necessary to measure the position of an object in a 360° radius. In such cases, it is conceivable to skip position measurement for objects detected in areas where position measurement is not required, but it is also possible to individually switch each image sensor 20 between an ON state (capturing image) and an OFF state (not capturing image). By turning on only some image sensors 20 and turning off the others, it becomes possible to customize the imaging range to suit the operating environment of the industrial robot 10, thereby achieving energy savings by reducing power consumption. In addition, the processing speed when measuring the position of an object will also be improved.

[0041] Figure 7 is a schematic plan view showing an example in which only some of the image sensors 20 are turned on. In this example, there is an obstruction 40 outside the industrial robot 10 that blocks the movement of the object, and the object can only approach the industrial robot 10 from the direction without the obstruction 40, i.e., from the upper side in the figure. In the example of Figure 7, by turning on only the two image sensors 20 located on the upper side in the figure and performing imaging, the object located on the upper side in the figure as seen from the industrial robot 10 can be detected in the overlapping portion A of the imaging ranges of the two image sensors 20, and its position can be measured.

[0042] In addition, the industrial robot 10 may be equipped with sensors such as torque sensors to detect contact with an object, which further improves the safety of the industrial robot 10 during operation.

[0043] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention. [Explanation of symbols]

[0044] 1: Robot System 2: Installation surface 10: Industrial robots 11: Base Link 12: Robotic Arm 20: Image sensor 30, 30a, 30b: Sensor base

Claims

1. Industrial robots that perform tasks within a workspace by operating a robotic arm, An image sensor that measures the position of an object while the industrial robot is in operation, A sensor base for mounting the image sensor is provided between the robot arm and the mounting surface of the industrial robot in the workspace, and remains stationary even while the industrial robot is in operation. It has, The aforementioned image sensor is a fisheye camera or a wide-angle camera. At least four of the image sensors are arranged on the sensor base at intervals in the circumferential direction surrounding the base of the industrial robot. A robot system characterized in that the overlapping portion where the imaging ranges of adjacent image sensors in the circumferential direction overlap is continuous over a 360° radius around the industrial robot.

2. The robot system according to claim 1, characterized in that the sensor base is a mounting stand on which the base of the industrial robot is mounted.

3. The robot system according to claim 2, characterized in that a plurality of the industrial robots are provided on a single mounting base.

4. The robot system according to claim 1, characterized in that the image sensor can be individually switched between an ON state in which imaging is being performed and an OFF state in which imaging is not being performed.

Images