Robotic system

Abstract

The present invention provides a robot system capable of easily generating a complete three-dimensional point group for a measurement object. The robot system comprises: a robot having an arm; a three-dimensional sensor mounted on the arm; and a three-dimensional point group generation unit that generates a three-dimensional point group for the measurement object based on three-dimensional data obtained by measuring the measurement object using the three-dimensional sensor. The three-dimensional point group generation unit generates the three-dimensional point group for the measurement object by synthesizing the three-dimensional data obtained by measuring the measurement object in an arbitrary coordinate system within the robot's operating area while changing the position of the three-dimensional sensor by moving the arm.

Description

Technical Field

[0001] The present invention relates to a robot system. Background Art

[0002] Conventionally, there are known robot systems that use a robot with an arm capable of gripping a workpiece to perform work (e.g., see Patent Document 1). The robot arm is equipped with a camera for identifying the workpiece. The robot system pre-stores the three-dimensional shape of the workpiece, and then recognizes the workpiece based on the three-dimensional shape recognized by the arm's camera, and grips the workpiece with the arm.

[0003] In a robot system that collaborates with a machine tool to process workpieces, the robot's arm grips the workpiece, performing the following tasks: placing the workpiece onto the machine tool's worktable before processing and removing the workpiece from the table after processing. The robot's arm movements during these operations are pre-trained by the operator. The robot's operating area can contain various obstacles that could interfere with the robot, so the operator must train the arm movements to prevent interference with obstacles.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-319938 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] To prevent interference between the robot and obstacles, it is also known to use a 3D sensor, fixed at a location separate from the robot, to pre-measure obstacles and generate a 3D point cloud of the obstacles. In this case, the robot uses the 3D point cloud to determine the presence of obstacles within its operating range and then maneuvers to avoid interference with the obstacles.

[0009] However, fixed-position three-dimensional sensors may not be able to measure areas, resulting in data omissions. For example, a fixed-position three-dimensional sensor cannot identify an area hidden in the shadow of an obstacle, resulting in data omissions. Therefore, when there are other obstacles in the shadow of the obstacle, the robot's arm may interfere with the obstacle during operation. In order to avoid data omissions, it is also considered to set up multiple three-dimensional sensors, or to change the position of the three-dimensional sensor and re-measure. However, in these cases, each time the three-dimensional sensor is set up, it needs to be calibrated, which is not practical. Therefore, a robot system is desired that can simply generate a three-dimensional point group without data omissions for the measurement object.

[0010] Solutions for solving problems

[0011] A robot system involved in one embodiment of the present disclosure comprises: a robot having an arm; a three-dimensional sensor arranged on the arm; and a three-dimensional point group generating unit, which generates a three-dimensional point group of the measurement object based on three-dimensional data obtained by measuring the measurement object by the three-dimensional sensor, wherein the three-dimensional point group generating unit synthesizes the three-dimensional data obtained by measuring the measurement object in an arbitrary coordinate system within the working area of ​​the robot while changing the position of the three-dimensional sensor by moving the arm to generate the three-dimensional point group of the measurement object.

[0012] Effects of the Invention

[0013] According to one embodiment, a robot system can be provided that can easily generate a three-dimensional point group without omissions for a measurement object. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a perspective view showing a robot system.

[0015] Figure 2 This is a block diagram showing the configuration of the robot system according to the first embodiment.

[0016] Figure 3 This is a flowchart illustrating a process for generating a robot motion program in the robot system according to the first embodiment.

[0017] Figure 4 This is a flowchart illustrating processing when generating a three-dimensional point group in the robot system according to the first embodiment.

[0018] Figure 5 It is a diagram illustrating the operation for generating a three-dimensional point group in the robot system according to the first embodiment.

[0019] Figure 6 This is a block diagram showing the configuration of a robot system according to the second embodiment.

[0020] Figure 7 It is a diagram illustrating an operation for generating a three-dimensional point group in the robot system according to the second embodiment.

[0021] Figure 8 This is an explanatory diagram for explaining the measurement range of a three-dimensional sensor when measuring a measurement object. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0023] (Overview of the Robot System)

[0024] Figure 1 The robot system 1 shown is installed near a processing chamber 100 where workpieces are processed. The robot system 1 includes a robot 3 mounted on a base 2 and a robot controller 4 that controls the operation of the robot 3. A plurality of workpieces W, which are to be worked on by the robot 3, are arranged on the base 2. A machine tool 200 is installed within the processing chamber 100 to perform predetermined processing on the workpieces W.

[0025] The robot 3 is a multi-jointed robot having an arm 32 movable in any direction via multiple joints on top of a main body 31 fixed to a base 2. The arm 32 is provided at the tip with a grip 33 for gripping a workpiece W, a three-dimensional sensor 34 capable of capturing images of the outside world, and a hand guide 35 for manually moving the arm 32 when gripped by an operator.

[0026] The robot 3 has a position detection sensor 36 (see Figure 2 The position detection sensor 36 is composed of, for example, an angle sensor provided on a drive motor (not shown) corresponding to the drive shaft of each joint of the arm 32. The position detection sensor 36 can obtain the rotation angle of each drive motor of the arm 32. This allows the position and posture of the gripping portion 33 of the arm 32 of the robot 3 to be detected.

[0027] The robot 3 moves its arm 32 through the opening 102 of the processing chamber 100, whose door 101 is open, and then moves according to a motion path based on the robot's motion program. This allows the robot 3 to place the unprocessed workpiece W, held by the gripping unit 33, onto the worktable 201 of the machine tool 200 within the processing chamber 100. Furthermore, the robot 3 moves the processed workpiece W, gripped by the gripping unit 33, from the worktable 201 of the machine tool 200. At this time, the robot 3's arm 32 is required to move in a manner that avoids interfering with obstacles such as the outer wall 103 of the processing chamber 100, including the door 101, or devices and components within the processing chamber 100.

[0028] The three-dimensional sensor 34 is comprised of, for example, a visual sensor. The three-dimensional sensor 34 images the outer wall 103 of the processing chamber 100, the interior of the processing chamber 100, and the workpiece W within the robot 3's operating area as measurement objects, acquiring three-dimensional data of the measurement objects. Specifically, the three-dimensional sensor 34 measures three-dimensional data, such as the distance distribution to the measurement objects, and outputs this data to the robot controller 4. The three-dimensional sensor 34 is mounted on the tip of the arm 32 alongside the grip 33, and its relative position with respect to the arm 32 is predetermined through calibration. Therefore, the position and posture of the grip 33 of the arm 32 are detected by the position detection sensor 36, and the position and posture of the three-dimensional sensor 34 are also detected.

[0029] (First embodiment of the robot system)

[0030] Figure 2 The configuration of the robot system 1 according to the first embodiment is shown. The robot control device 4 includes a three-dimensional point cloud generation unit 41 , an obstacle information generation unit 42 , a storage unit 43 , a control unit 44 , an arm driving unit 45 , and a robot motion program generation unit 46 .

[0031] The 3D point cloud generation unit 41 generates and outputs a 3D point cloud based on the 3D data measured by the 3D sensor 34. A 3D point cloud is a collection of multiple points distributed on the surface of one or more objects (measurement objects) existing in three-dimensional space. The 3D point cloud generation unit 41 generates a 3D point cloud of the measurement object by synthesizing the multiple 3D data measured by the 3D sensor 34 and outputs the generated 3D point cloud to the obstacle information generation unit 42. Furthermore, if the measurement object is a workpiece W, the 3D point cloud generation unit 41 outputs the measured 3D point cloud of the workpiece W to the storage unit 43.

[0032] The obstacle information generation unit 42 generates obstacle information based on the three-dimensional point group of the measurement object, which is an obstacle, generated by the three-dimensional point group generation unit 41. This obstacle information indicates the locations of obstacles within the working area of ​​the robot 3 that could potentially interfere with the movement of the arm 32. Since the working range of the robot 3 (the range of movement of the arm 32) is predetermined, the locations of obstacles that could potentially interfere with the arm 32 can be determined within the three-dimensional point group. The obstacle information generated by the obstacle information generation unit 42 is transmitted to the storage unit 43, where it is stored and registered.

[0033] The control unit 44 controls the arm driving unit 45 based on the position information of the arm 32 detected by the position detection sensor 36. The control unit 44 controls the arm driving unit 45 to move the arm 32 and to cause the gripping unit 33 to grip the workpiece W.

[0034] The robot motion program generation unit 46 generates a motion program for the robot 3 to perform work on the workpiece W. The robot motion program includes information about the motion path of the robot 3 during work. The motion path of the robot 3 is created based on the obstacle information generated by the obstacle information generation unit 42. The robot motion program generated by the robot motion program generation unit 46 is sent to the storage unit 43, where it is stored and registered.

[0035] Then, based on Figure 3 The flowchart shown in FIG. 1 is used to explain a process of generating a robot motion program for performing work on a workpiece W in the robot system 1 . The process of generating the robot motion program is executed according to a predetermined process program pre-stored in the robot control device 4 .

[0036] First, the robot motion program generator 46 acquires and registers the initial position of the robot 3 (S1). The initial position of the robot 3 is acquired by the position detection sensor 36. Next, the robot motion program generator 46 controls the arm drive unit 45 via the control unit 44 to move the arm 32, and the three-dimensional sensor 34 measures the workpiece W. This acquires and registers the position of the workpiece W (S2). The robot motion program generator 46 then creates the initial robot motion program (S3).

[0037] The initially created robot motion program is a tentative motion program that includes the motion path of the robot 3 until the arm 32 grasps the workpiece W and places it on, for example, the worktable 201. Information about obstacles that could interfere with the arm 32 is not necessarily reflected in this motion program. Therefore, the robot motion program generator 46 switches the robot system 1 mode to the obstacle information generation mode and acquires and registers the obstacle information (S4).

[0038] Further based on Figure 4 The flowchart shown in FIG. 4 is used to illustrate the specific processing for obtaining obstacle information in step S4.

[0039] First, the arm 32 is moved to change the position of the three-dimensional sensor 34 relative to the object being measured, thereby acquiring three-dimensional data (S41). The object being measured is an object within the operating range of the robot 3 that could interfere with the arm 32. Specifically, the object being measured is the outer wall 103 of the processing chamber 100, or devices and components located within the processing chamber 100.

[0040] In this embodiment, the movement of the arm 32 when the three-dimensional sensor 34 measures the object to be measured is as follows: Figure 5Specifically, the operator OP manually grasps the handheld guide 35 at the front end of the arm 32 and directly moves the arm 32 manually in an arbitrary coordinate system within the operating range of the robot 3 while checking whether there are any obstacles in the movement path of the arm 32.

[0041] Even if there are hidden obstacles that are not visible from the robot 3 within the operating range of the robot 3 (for example, devices and components hidden behind the door 101 and the outer wall 103), the robot 3 can still move forward by Figure 5 As shown, the operator OP manually moves the arm 32 to the vicinity of the hidden obstacle to reliably perform measurement.

[0042] As described above, while the operator OP manually moves the arm 32 relative to the object being measured, the three-dimensional sensor 34 measures the object in an arbitrary coordinate system within the operating range of the robot 3 and acquires a plurality of three-dimensional data. The three-dimensional sensor 34 outputs the acquired plurality of three-dimensional data to the three-dimensional point cloud generation unit 41 of the robot control device 4.

[0043] The 3D point cloud generator 41 synthesizes a plurality of 3D data acquired by the 3D sensor 34 to generate a 3D point cloud of the measurement object ( S42 ). The 3D point cloud data generated by the 3D point cloud generator 41 is output to the obstacle information generator 42 .

[0044] The obstacle information generation unit 42 generates obstacle information related to the positional information of obstacles that may interfere with the arm 32 based on the three-dimensional point cloud sent from the three-dimensional point cloud generation unit 41 (S43). The obstacle information generated by the obstacle information generation unit 42 is stored in the storage unit 43 (S44). This terminates the obstacle information generation mode.

[0045] After obtaining the obstacle information through the above steps, the robot motion program generation unit 46 returns to Figure 3 The process is shown in FIG. The robot motion program generator 46 modifies the initially created robot motion program based on the obstacle information acquired in the obstacle information generation mode (S5). Thus, the robot motion program generator 46 reflects all obstacles that could potentially interfere with the arm 32 based on the obstacle information and generates a robot motion program that includes a motion path for the robot 3 that avoids interference with obstacles. The generated robot motion program is sent to the storage unit 43 and stored.

[0046] The robot system 1 then automatically operates the robot 3 based on a robot motion program that includes information about obstacles that could potentially interfere with the arm 32, thereby performing the task of grasping and transporting the workpiece W (S6). Because the robot motion program that operates the automatically operated robot 3 includes the obstacle information, which is composed of a comprehensive three-dimensional point group including information about hidden obstacles that are not visible from the location where the robot 3 is installed, interference between the arm 32 and obstacles during the robot 3's operation is reduced or eliminated.

[0047] The robot system 1 according to the first embodiment achieves the following advantages. Specifically, the three-dimensional point cloud generation unit 41 generates a three-dimensional point cloud of the object by synthesizing three-dimensional data obtained by measuring the object while changing the position of the three-dimensional sensor 34 by moving the arm 32 in an arbitrary coordinate system within the robot 3's work area. This allows for the simple generation and acquisition of a three-dimensional point cloud for the object without missing any data.

[0048] The three-dimensional point cloud generation unit 41 synthesizes the three-dimensional data of the object being measured, obtained by the operator OP manually moving the arm 32 to change the position of the three-dimensional sensor 34, to generate a three-dimensional point cloud of the object. This allows the object to be measured from various viewpoints, and the three-dimensional sensor 34 can easily and comprehensively measure obstacles within the robot 3's operating range.

[0049] Obstacle information acquired in this way does not change even if the movement path of the robot 3 changes due to a change in the type of workpiece W. Therefore, there is no need to regenerate new obstacle information using the three-dimensional sensor 34 or re-teach the movement path of the arm 32 every time the type of workpiece W changes.

[0050] The three-dimensional sensor 34 provided on the arm 32 also serves as a three-dimensional sensor used during operation to recognize the workpiece W. Therefore, there is no need to provide separate three-dimensional sensors for generating obstacle information and for recognizing the workpiece W, and an inexpensive robot system 1 can be constructed.

[0051] The 3D point cloud generation unit 41 synthesizes the 3D data of the object being measured, obtained by the operator OP directly grasping the handheld guide 35 of the arm 32 and manually moving the arm 32 to change the position of the 3D sensor 34, thereby generating a 3D point cloud of the object. This allows for easy generation of a comprehensive 3D point cloud. However, the 3D point cloud generation unit 41 may also synthesize the 3D data of the object being measured, obtained by the operator OP directly grasping the handheld guide 35 of the arm 32 and manually moving the arm 32 to change the position of the 3D sensor 34, thereby generating a 3D point cloud of the object.

[0052] (Second embodiment of the robot system)

[0053] In the robot system 1 according to the first embodiment, the operator OP manually moves the arm 32 while checking for the presence of obstacles while measuring the object using the three-dimensional sensor 34. However, the positional relationship between obstacles within the operating range of the robot 3 and the robot 3 may already be roughly determined. In such cases, the robot system 1 may automatically move the arm 32 based on a predetermined operating program.

[0054] Figure 6 The structure of the robot system 1A according to the second embodiment is shown. In the robot control device 4A, Figure 2 The robot control device 4 shown has an additional operation program storage unit 47 for generating obstacle information.

[0055] The obstacle information generation operation program storage unit 47 stores in advance an obstacle information generation operation program for automatically moving the arm 32 when measuring the measurement object using the three-dimensional sensor 34. The obstacle information generation operation program includes operation commands for the robot 3 for moving the arm 32 within a range where it is assumed that obstacles known in advance will not interfere with the arm 32. Therefore, when the robot operation program generation unit 46 of the robot control device 4A uses the three-dimensional sensor 34 to measure the measurement object in the obstacle information generation mode, as shown in FIG. Figure 7 As shown, the arm driving unit 45 is controlled based on the obstacle information generation operation program to automatically move the arm 32 .

[0056] In the robot system 1 equipped with the robot control device 4A, the specific operation when measuring the object to be measured using the three-dimensional sensor 34 is based on Figure 4 That is, in Figure 4In step S41, the robot motion program generator 46 reads the obstacle information generation motion program from the obstacle information generation motion program storage unit 47 to replace the operator OP in manually moving the arm 32. Based on the read obstacle information generation motion program, the robot motion program generator 46 controls the arm drive unit 45 via the control unit 44 to automatically move the arm 32, thereby performing measurement of the measurement object by the three-dimensional sensor 34. In this way, the three-dimensional data obtained by the three-dimensional sensor 34 measuring the obstacles existing in the working range of the robot 3 is obtained. Thereafter, the following steps are executed: Figure 4 The same processing is performed from step S42 to step S44 shown.

[0057] In this robot system 1A, similar to the robot system 1 according to the first embodiment, a three-dimensional point cloud can be easily generated for the measurement object without missing any data. Since the operator OP does not need to manually move the arm 32, obstacle information can be acquired more quickly and easily.

[0058] It is desirable to generate an action program for generating obstacle information based on the measurement range of the three-dimensional sensor 34. Figure 8 As shown, the obstacle information generation action program causes the robot 3 to move in such a way that the measurement range X1 of the three-dimensional sensor 34 before the arm 32 moves is close to the measurement range X2 of the three-dimensional sensor 34 after the arm 32 moves, or in such a way that the measurement range X1 and the measurement range X2 partially overlap. Figure 8 The outer wall surface 103 of the processing chamber 100 is shown as the measurement object and is measured by the three-dimensional sensor 34. Therefore, even when the arm 32 is automatically moved to measure the measurement object, the three-dimensional sensor 34 can measure the measurement object without omission.

[0059] The storage unit 43 may also function as the obstacle information generation operation program storage unit 47. The obstacle information generation operation program may be read into the robot control unit 4A from, for example, an external storage device such as a server, when the three-dimensional sensor 34 measures the measurement object. The robot control unit 4A may also be configured to include a switch (not shown) that switches whether the movement of the arm 32 during measurement of the measurement object by the three-dimensional sensor 34 is performed manually by the operator OP or automatically based on the obstacle information generation operation program, allowing the operator OP to select either mode.

[0060] In the above embodiments, the three-dimensional point cloud generation unit 41, the obstacle information generation unit 42, and the robot motion program generation unit 46 constitute part of the functions of the robot control unit 4 or 4A, but this is not limiting. At least one of the three-dimensional point cloud generation unit 41, the obstacle information generation unit 42, and the robot motion program generation unit 46 may be provided separately from the robot control unit 4 or 4A. The arm drive unit 45 may also be provided separately from the robot control unit 4 or 4A. The obstacle information generation motion program storage unit 47 may also be provided separately from the robot control unit 4A.

[0061] Description of Reference Numerals

[0062] 1. 1A: Robot system; 3: Robot; 32: Arm; 34: Three-dimensional sensor; 41: Three-dimensional point group generation unit; 43: Obstacle information generation unit; 46: Robot motion program generation unit; W: Workpiece.

Claims

1. A teaching system for generating a motion program for a robot, the teaching system comprising: a robot having an arm; a three-dimensional sensor disposed on the arm; a three-dimensional point group generating unit for generating a three-dimensional point group of the measurement object based on three-dimensional data obtained by measuring the measurement object using the three-dimensional sensor; an obstacle information generating unit configured to generate obstacle information based on the three-dimensional point group; as well as a robot motion program generating unit that generates a robot motion program including a motion path of the robot that avoids interference with obstacles based on the obstacle information; The three-dimensional point group generating unit generates the three-dimensional point group of the measurement object by synthesizing the three-dimensional data obtained by measuring the measurement object in an arbitrary coordinate system within the working area of ​​the robot while directly moving the arm by the operator to change the position of the three-dimensional sensor. The robot operation program generating unit stores the robot operation program in a storage unit.

2. The teaching system according to claim 1, wherein: The three-dimensional sensor also serves as a three-dimensional sensor for recognizing a workpiece.

3. A robot control device for controlling a robot having an arm provided with a three-dimensional sensor, the robot control device comprising: a three-dimensional point group generating unit for generating a three-dimensional point group of the measurement object based on three-dimensional data obtained by measuring the measurement object using the three-dimensional sensor; an obstacle information generating unit configured to generate obstacle information based on the three-dimensional point group; as well as a robot motion program generating unit that generates a robot motion program including a motion path of the robot that avoids interference with obstacles based on the obstacle information; The three-dimensional point group generating unit generates the three-dimensional point group of the measurement object by synthesizing the three-dimensional data obtained by measuring the measurement object in an arbitrary coordinate system within the working area of ​​the robot while directly moving the arm by the operator to change the position of the three-dimensional sensor. The robot operation program generating unit stores the robot operation program in a storage unit.

4. The robot control device according to claim 3, wherein: The three-dimensional sensor also serves as a three-dimensional sensor for recognizing a workpiece.

Images