JP6904759B2 - Robot movement speed control device and method - Google Patents

Description

The present invention relates to a movement speed control device and a method for limiting the movement speed of an industrial robot when teaching (teaching) the robot.

In the teaching playback type robot, it is necessary to teach the robot in advance the operation to be executed by the robot. When teaching the working position of a horizontal articulated robot, the operation is performed in the Cartesian coordinate system (XYZ coordinate system), and the moving speed of the robot is the working point (the point to be taught and generally the tip of the arm). Specify by the linear velocity of. During normal operation, no one enters the robot's operating space and there is no harm to the operator, but when teaching the robot, the worker (also called a teacher) who teaches. ) Will approach the robot, and the movement of the robot may cause harm to the teacher. In particular, in teaching of a so-called transfer robot that conveys an article in a narrow space called a chamber or the like, the instructor enters the chamber and teaches, so that the robot is more likely to collide with the instructor. In order to eliminate the risk of such harm, it is required that the moving speed of the tip of the robot during teaching be set to a predetermined upper limit speed (for example, 250 mm / sec) or less.

Patent Document 1 discloses that a detection device for detecting the position of a teacher is provided, and the operating speed of the robot is automatically reduced when the teacher approaches the robot. Patent Document 2 discloses that the acceleration and speed of the tip end portion of the robot arm are detected, and the robot is stopped in an emergency when either of them becomes larger than a predetermined value. Patent Document 3 is for driving each axis so as to move the tip of the robot at a speed as close as possible to the speed commanded by an operation command from the teaching device while limiting the moving speed of the tip of the robot to a predetermined upper limit speed or less during teaching. It discloses a method of calculating the command speed of. Patent Document 4 does not relate to ensuring safety during teaching, but when the rated speed is determined for each axis of the robot, the speed of each axis is based on the speed data of the robot tip given by teaching. Is calculated and the speed data is corrected when the rated speed of any of the axes is exceeded.

International Publication No. 2004/09303 Japanese Unexamined Patent Publication No. 6-91587 Japanese Unexamined Patent Publication No. 9-1903060 Japanese Unexamined Patent Publication No. 5-233052

The method of detecting the position of the teacher as described in Patent Document 1 requires a detection device, so that it tends to be large-scale and the cost tends to increase. The method of ensuring the safety of the teacher without providing a detection device for detecting the position of the teacher is basically to set the speed of the tip of the robot to be equal to or less than a predetermined upper limit speed. However, considering, for example, a horizontal articulated robot in which two arms are connected so that both of these arms can move in a horizontal plane (XY plane), the connection position between the arms rather than the tip of the robot (that is, that is). The joints) may move faster. It is possible to limit the moving speed of the robot by calculating the speed of the joints one by one, but the burden of calculation processing is large. Therefore, it is desired that the moving speed of the robot during teaching can be limited by a simple mechanism in consideration of joints that may move at high speed.

An object of the present invention is to provide a moving speed control device and a method capable of further improving the safety of the robot during teaching with a simple mechanism when there is a part that moves faster than the tip of the robot. be.

The movement speed control device of the present invention includes a main body, a first arm whose one end side is connected to the main body, a first motor that rotates the first arm with respect to the main body, and one end side of the other end of the first arm. A movement speed control device that controls a robot that is a horizontal articulated robot including at least a second arm connected to the side and a second motor that rotates the second arm with respect to the first arm, and is an orthogonal coordinate system. When teaching a horizontal articulated robot, input instructions for movement speed using different limit values determined based on the coordinates of the position of the tip of the robot on the second arm side in the orthogonal coordinate system. When the value exceeds the limit value, the robot is moved by the movement speed that limits the input instruction value by the limit value, and the limit value based on the current position of the tip after movement is equal to or more than the input instruction value and the robot's current position. the moving speed queries of speed increase when below the input instruction value, a control unit Before moving the robot by the moving speed indicated by the input instruction value when the increase instruction is inputted to the query.

In the method of the present invention, the main body portion, the first arm whose one end side is connected to the main body portion, the first motor that rotates the first arm with respect to the main body portion, and one end side are connected to the other end side of the first arm. It is a method of controlling a robot which is a horizontal articulated robot including at least a second arm for rotating the second arm with respect to the first arm, and a horizontal articulated robot in an orthogonal coordinate system. When teaching a horizontal articulated robot under control, the input instruction value for the movement speed is set using a different limit value that is determined based on the coordinates of the position of the tip of the robot on the second arm side in the orthogonal coordinate system. When the limit value is exceeded, the robot is moved by the movement speed that limits the input instruction value by the limit value, and the limit value based on the current position of the tip after movement is equal to or more than the input instruction value and the robot's current movement. query the speed increase when the speed falls below the input instruction value, Before moving the robot by the moving speed indicated by the input instruction value when the increase instruction is inputted to the query.

When the tip of the horizontal articulated robot is moved by the control by the Cartesian coordinate system, the movement locus of the connecting portion of the two arms becomes large, and this connecting portion (joint portion or elbow of the robot) may move at high speed. This movement is an unexpected movement for the teacher and may not be avoided by the teacher, but it approaches the robot by limiting the movement speed by a limit value determined based on the coordinates of the tip in the Cartesian coordinate system. It is possible to increase the safety for the teacher. The limit value can be set so that, for example, the shorter the distance between the tip and the origin of the Cartesian coordinate system, the smaller the limit value. Alternatively, for example, the coordinates of the tip can be set to (x, y) so that the smaller of | x | and | y |, the smaller the limit value.

In the present invention, one end side of the first arm is set as the origin, and a plane including the origin and parallel to the movable range of the tip can be divided into a plurality of regions, and a single limit value can be set for each region. .. By setting the limit value in this way, the calculation load can be reduced as compared with the case where the angular velocity of each joint is calculated and the movement speed is limited. The area can be divided into a area defined by a square centered on the origin in a plane including the origin and parallel to the movable range of the tip. When the area is set in this way, assuming that the XY coordinates of the tip position are (x, y), simply apply a comparison formula for x and y or a formula for calculating the sum of the absolute values of x and y. The limit value can be determined, and the calculation load is light. As another method of dividing the region, it can be a region defined by concentric circles centered on the origin. In this case, a square operation is required, but the movement speed is not excessively limited.

In the present invention, when the current moving speed exceeds the limit value based on the current position of the tip while the robot is moving, the moving speed of the robot may be updated by the limit value based on the current position of the tip. .. With such a configuration, safety can be further improved, for example, when the tip of the robot moves so as to approach the origin. Further, in the present invention, during the continuous period of the operation for instructing the movement of the robot, the robot is moved at the movement speed limited at the start of this period, and when the operation is restarted after the operation is completed, the resumption is resumed. The moving speed may be limited based on the coordinates of the tip of the time. In this configuration, the movement speed is limited according to the position of the tip at that time each time the operation for instructing the movement is restarted. Therefore, the calculation load is reduced as compared with the case where the tip position is sequentially acquired, and the operation is substantially reduced. The safety can be further improved. Here, the operation of instructing the movement of the robot is, for example, an operation of pressing a push button provided on the teaching pendant. The robot continues to move while the push button is pressed, and when the finger is released from the push button, the robot continues to move. It stops the movement of.

In the present invention, the movement speed control device is configured as a teaching pendant connected to the robot controller of the robot, and the teaching pendant is provided with an auxiliary storage unit for storing a parameter table that describes a limit value according to the coordinates of the tip. The input indicated value may be limited by using the limit value obtained by referring to the parameter table. With this configuration, the processing load can be distributed without imposing a processing load on the robot controller. Further, when the teaching pendant is connected to the robot controller, the parameter table may be read from the robot controller into the auxiliary storage unit. Since the teaching pendant is a small device and can be shared with other robots, by allowing the parameter table to be read from the robot controller into the teaching pendant, teaching of multiple types of robots using a single teaching pendant It will be possible to carry out with higher safety.

According to the present invention, when there is a portion that moves faster than the tip of the robot, the safety when teaching the robot is further enhanced by a simple mechanism.

It is a figure which shows an example of the structure of the robot to which the moving speed limiting method of this invention is applied. It is a block diagram which shows the structure of a robot controller and a teaching pendant. It is a flowchart explaining the process of limiting the moving speed of a robot. It is a figure which shows an example of the contents of a parameter table. It is a figure explaining the relationship between the position of a tip and the moving speed after restriction. It is a flowchart explaining another example of the process which limits the moving speed of a robot. It is a figure explaining an example of the moving motion of a robot. It is a figure explaining another example of the moving motion of a robot.

Next, an embodiment of the present invention will be described with reference to the drawings. In the present invention, when teaching a horizontal articulated robot by operating in a Cartesian coordinate system (XYZ coordinate system), the tip of the robot moves based on the positional relationship between the tip of the robot and the origin O preset in the robot. The speed of the robot during teaching is limited by the position of the tip of the robot (XY coordinates) so that the robot can operate at low speed when it is close to the origin O and the robot can operate at high speed when the tip is away from the origin O. ..

FIG. 1 shows an example of a robot to which the movement speed control method based on the present invention is applied in one embodiment of the present invention, and FIG. 1A is a perspective view showing a movable portion of the robot 10. , (B) is a mechanical diagram of the robot 10. Here, it is assumed that the Cartesian coordinate system (XYZ coordinate system) is defined as indicated by the arrows in the figure. The robot 10 is a horizontal articulated robot, and includes an arm portion including a first arm 13 and a second arm 15 connected to each other via a connecting portion 14. The base end side of the first arm 13 is attached to the main body portion 11 via the connecting portion 12, and the first arm 13 is rotatable about the connecting portion 12 in the XY plane. Further, the base end side of the second arm 15 is connected to the tip end side of the first arm via the connecting portion 14, and the second arm 15 can rotate around the connecting portion 14 in the XY plane. Further, a hand 17 is provided on the tip end side of the second arm 15 via a connecting portion 16. The connecting portions 12, 14 and 16 are all made of, for example, a cylindrical joint, a motor and a speed reducer. The robot 10 is used for transporting articles and the like, and the hand 17 is always oriented in the same direction in the XY plane by a link or the like or by motor control. That is, the hand 17 only translates in the XY plane. The movable range of the hand 17 is the XY plane or a plane parallel to the XY plane. In the following description, it is assumed that the movable range of the hand 17 is the XY plane, ignoring the thickness of the first arm 13 and the second arm 15 in the Z direction.

The robot 10 is further provided with a robot controller 30 that causes the robot to perform a predetermined movement by driving motors 22, 24, 26, ... Provided in the robot 10. Here, the motors 22, 24, and 26 are, for example, motors built in the connecting portions 12, 14, and 16 and used for rotating the arms 13, 15 and the hand 17, respectively.

A teaching pendant 40 operated by the instructor when teaching the robot 10 is connected to the robot controller 30 via a cable 50. The robot controller 30 includes a robot drive unit 31 including a driver for driving motors 22, 24, 26, ..., A calculation unit 32 that performs calculations necessary for the robot 10 to execute a predetermined movement, a flash memory, and the like. It has an auxiliary storage unit 33 including the auxiliary storage unit 33, and a communication unit 34 that communicates with the teaching pendant 40 via the cable 50. The auxiliary storage unit 33 stores the operation parameters of the robot 10 and the like as a parameter file, and also stores the teaching result and the like.

The teaching pendant 40 includes an input unit 41 composed of a touch panel, buttons, switches and the like for inputting commands from the instructor, a display unit 42 composed of a liquid crystal display and the like for displaying information to the instructor, and teaching. It has a control unit 43 that controls the robot during necessary calculations and teaching, an auxiliary storage unit 44 including a flash memory, and a communication unit 34 that communicates with the robot controller 30 via a cable 50. .. The auxiliary storage unit 44 stores a parameter file related to the specifications and operating conditions of the robot 10. The teaching pendant 40 itself can be used in common by different types of robots, and when connected to a robot to be taught, the above-mentioned parameter file related to the robot is read from the robot and stored in the auxiliary storage unit 44. do. In the present embodiment, the moving speed of the robot at the time of teaching is limited based on the position of the tip of the robot 10, but how to limit the moving speed differs depending on the specifications of the robot and the like. Therefore, the parameter file for limiting the movement speed is also stored in advance in the auxiliary storage unit 33 of the robot controller 30 of the robot for each robot, and when the teaching pendant 40 is connected, the auxiliary storage unit of the robot controller 30 is stored. From 33, it can be stored in the auxiliary storage unit 44 of the teaching pendant 40. In the present embodiment, the process of limiting the moving speed itself is executed by the teaching pendant 40, and the moving speed command after the limitation is sent from the teaching pendant 40 to the robot controller 30, so that the teaching pendant 40 limits the moving speed based on the present invention. It corresponds to the device.

In the teaching of the robot 10, the hand 17 is set as the teaching target and the hand 17 is moved to the target position. As described above, since the hand 17 only translates in the XY plane, the moving speed in the Cartesian coordinate system is the same throughout the hand 17. Therefore, in the following description, the position of the connecting portion 16 between the hand 17 and the second arm 15 is treated as the tip of the second arm 15 of the robot 10, that is, the tip of the arm portion, and this tip is used as a working point. The moving speed of the robot 10 during teaching is limited based on the position of this tip in the Cartesian coordinate system, that is, the coordinate value of the tip. In the robot 10 shown in FIG. 1, the position of the working point of the robot 10 is determined by the rotation of the two axes of the first arm 13 and the second arm 15. Here, assuming that the work point is moved by a certain distance in the XY plane based on the Cartesian coordinate system, the rotation angles of the arms 13 and 15 are such that the work point is near the outer circumference or the center of the work area of the robot 10. It depends on what you have. Considering that the connecting portion 14 between the first arm 13 and the second arm 15 is an elbow or a joint portion in the arm portion, the movement of the elbow portion is such that the movement distance of the tip portion is short and the movement thereof is near the center of the work area. Even if the speed is slow, it may rotate larger and faster than the teacher expected. Since the rotation of the elbow portion is centered on the connecting portion 12 between the main body portion 11 and the first arm 13, the position of the connecting portion 12 on the XY plane is set as the origin O in the following description.

The control unit 43 of the teaching pendant 40 controls the position of the tip of the second arm 15, which is a work point, by the Cartesian coordinate system based on the input to the input unit 41. At this time, the control unit 43 controls the robot 10 with different upper limit values determined based on the coordinates of the tip of the second arm 15 in the XY coordinate system in order to prevent the elbow from rotating large and fast during teaching. do. This upper limit value is called a limit value. FIG. 3 shows a procedure of a specific example of such a process. First, in step 101, the moving speed is input to the input unit 41 in order for the instructor to set the moving speed of the robot. For example, with 250 mm / sec as 100%, the moving speed is input by the instructor inputting a numerical value in the range of 1 to 100%. The movement speed input by the instructor is defined as the input instruction value Vin. The control unit 43 acquires the coordinate value of the position of the tip of the second arm 15 in step 102, and acquires the limit value Vlim of the moving speed corresponding to the acquired position in step 103. The limit value Vlim may be determined, for example, based on a parameter table read in advance from the robot controller 30 into the auxiliary storage unit 44 of the teaching pendant 40, or may be obtained by calculation. A specific example of the limit value Vlim corresponding to the position of the tip of the second arm 15 will be described later, but the point is that when the tip of the second arm is close to the origin O, the limit value Vlim is reduced. That is.

Next, in step 104, the control unit 43 determines whether or not the input instruction value Vin is larger than the limit value Vlim. When the input instruction value Vin exceeds the limit value Vlim (Vin> Vlim), the limit value Vlim is set as the speed command value Vcmd in step 105, and in other cases, the input instruction is in step 106. The value Vin is used as it is as the speed command value Vcmd. If the speed command value Vcmd is determined in step 105 or 106, the control unit 43 sends a speed command to the robot controller 30 in step 110 so as to drive the robot by the speed command value Vcmd. In this way, when the input instruction value Vin for the moving speed is larger than the limit value Vlim determined according to the position of the tip of the second arm 15 at the time when the input instruction value Vin is input, the robot 10 , The movement speed is limited to the limit value Vlim and operates.

When using the teaching pendant 40 in which the robot 10 moves only during the period when a specific switch such as an operation button is operated during teaching, when the above process is executed, the operation button is operated. The movement is started based on the limit value at that time, and the speed is maintained while the operation button is operated. If you release your finger from the operation button here, it will be in the non-operation state, so if the operation button is operated again after the non-operation state, the limit value will be set according to the position of the tip at the time of re-operation. The robot can be made to start moving at a limited movement speed. By adopting such an operation mode, the moving speed can be set according to the position of the tip of the robot 10, so that the teaching efficiency can be improved. Further, when the tip of the robot 10 moves in a direction approaching the origin O, the moving speed is further restricted as the tip approaches the origin by performing the intermittent operation in this way, so that the safety is further enhanced. Here, the limit value is set according to the position of the tip at the time of re-operation, but as will be described later, the current position of the tip is acquired in real time while the operation button is being operated, and the current position of the tip is acquired according to the acquired position. The movement speed may be limited.

Next, a method of determining the limit value Vlim corresponding to the position of the tip of the second arm 15 will be described. FIG. 4 shows an example of the contents of the parameter table used to determine the limit value Vlim. Here, an index L indicating how far the tip of the second arm 15 is from the origin O is introduced. The index L is introduced to prevent the tip of the second arm 15 from moving unexpectedly fast because it is near the origin O, and as a whole, it becomes a small value when the tip is near the origin O. Is determined to be. However, the magnitude of the actual distance (Euclidean distance) does not necessarily have to be the magnitude of the index L as it is. The parameter table as shown in FIG. 4 is used when the XY plane is divided into a plurality of regions and each region defines a single limit value Vlim according to how far the region is from the origin. It is a thing. In the example shown here, the index L is divided into five stages of 0 or more and less than D1, D1 or more and less than D2, D2 or more and less than D3, D3 or more and less than D4, and D4 or more, and each of these stages is restricted. The values V1, V2, V3, V4 and V5 are assigned. Here, V1 <V2 <V3 <V4 <V5, and the smaller the index L, the smaller the limit value Vlim. Then, by searching this parameter table based on the index L, the limit value Vlim can be obtained.

FIG. 5 is a diagram showing the relationship between the position of the tip of the input instruction value Vin at the time of input and the upper limit of the moving speed limited by the limit value Vlim (that is, the limit value Vlim). Let (x, y) be the coordinates of the position of the tip of the second arm 15 on the XY plane. FIG. 5A shows a case where the larger of the absolute value | x | of the X coordinate and the absolute value | y | of the position of the tip of the second arm 15 on the XY plane is used as the index L. There is. The region for each limit value Vlim is defined by a square centered on the origin and having sides parallel to each of the X-axis and the Y-axis. In the illustrated one, if the tip position is P1, the limit value is V3, and if the tip position is P2, the limit value is V4. In the one shown in FIG. 5A, since the index L is derived by finding the XY coordinates of the tip position and performing only a few comparison operations, the amount of calculation for obtaining the index L is small and the calculation is performed at high speed. Has the advantage of being able to do. On the other hand, in the one shown in FIG. 5B, the normal distance (Euclidean distance) between the tip position of the second arm 15 and the origin O in the XY plane is used as an index L (that is, L ² = x ² + y ² ). Zones are divided for each index L. In other words, the region defined by the concentric circles in the XY plane is the region of each limit value Vlim. P1 and P2 in FIG. 5 (b) are at the same positions on the XY plane as P1 and P2 in FIG. 5 (a), but in the case shown in FIG. 5 (b), if the position of the tip is P1. As in the case of FIG. 5 (a), the limit value is V3, and if the position of the tip is P2, the limit value becomes larger than in the case of FIG. 5 (a) and becomes V5. When the distance is used as the index L, a square operation for each of the X and Y coordinates of the tip position and an operation for obtaining the sum thereof are required in addition to the comparison operation, which increases the amount of calculation, but the actual distance. Since it is based on, there is an advantage that the movement speed is not excessively limited as shown here with respect to the position P2. As a modification of the one shown in FIG. 5A, there is one in which L = | x | + | y |. In this case, the region for each index L is a region defined by a square whose diagonal lines are the X-axis and the Y-axis.

In the one shown in FIG. 5, the XY plane is divided into several regions, and the limit value Vlim is set based on which region the position of the tip of the second arm 15 exists, but the index L The method of determining the limit value Vlim according to the above is not limited to this. For example, the limit value Vlim may be set by a function that increases monotonically according to the index L (for example, a linear function proportional to the index L). The index L here may be a normal distance or may be the larger of the absolute value of the X coordinate and the absolute value of the Y coordinate of the tip position.

In the process shown in the flowchart in FIG. 3, the moving speed of the robot 10 is limited based on the index L of how far the tip of the second arm 15 is from the origin O at the time when the input instruction value Vin is input. ing. Here, consider a case where the robot 10 is moved in a direction in which the tip of the arm portion moves away from the origin O, as in the movement from the position P3 to the position P4 in FIG. 5A. At this time, the moving speed is limited by V3, which is the limit value at the position P3, and the robot 10 moves at a speed equal to or lower than the limit value V3. However, since the limit value Vlim increases as the distance from the origin O increases, the moving speed of the robot 10 is increased within the range of the input instruction value Vin, and a safety problem is unlikely to occur. Further, in the case of a movement approaching the origin O such as the movement from the position P5 to the position P6 in FIG. 5B, when the movement is performed at the limit value V4 corresponding to the position P5, in the vicinity of the position P6. The elbow movement speed may be excessive. Therefore, it is conceivable to change the control for limiting the moving speed of the robot 10 every moment according to the current position of the tip of the second arm 15. FIG. 6 shows a process in which the control of the movement speed limit is changed at any time according to the current position of the tip.

In the process shown in FIG. 6, the process of steps 101 to 106, 110 is performed in the same manner as that shown in FIG. After the execution of step 110, the control unit 43 acquires the current position of the tip in step 111, and acquires the limit value Vlim corresponding to the current position acquired in step 112. The current position does not mean the position at the time of input of the input instruction value Vin, but the position of the tip at the present time during the movement of the robot 10. The method for obtaining the limit value Vlim is the same as that described with reference to FIG. Next, in step 113, the control unit 43 determines whether the input instruction value Vin is larger than the speed command value Vcmd at that time and is equal to or less than the limit value Vlim corresponding to the current position (that is, Vlim ≧ Vin> Vcmd). To judge. When Vlim ≧ Vin> Vcmd, the moving speed can be increased to the input instruction value Vin. Therefore, in step 114, the control unit 43 refers to the instructor via the display unit 42. An inquiry is made as to whether or not to increase the speed, and in step 115, it is determined whether or not the instructor has instructed to increase the speed. The speed increase instruction is input by the teacher operating, for example, a button provided on the teaching pendant 40. When it is determined in step 115 that the speed increase instruction has been given, the control unit 43 sets the input instruction value Vin already input in step 101 as the speed command value Vcmd in step 116, and then the process proceeds to step 119. move on. On the other hand, when there is no instruction to increase the speed in step 115, the process proceeds to step 119 without changing the speed command value Vcmd.

If Vlim ≧ Vin> Vcmd does not hold in step 113, the control unit 43 determines in step 117 whether the speed command value Vcmd exceeds the limit value Vlim, and if it exceeds the limit value Vlim, step 118. In, the movement speed is limited by setting the limit value Vlim to the speed command value Vcmd, and after the movement speed is limited, the process proceeds to step 119. If Vcmd> Vlim is not set in step 117, the process proceeds to step 119 without changing the speed command value Vcmd. In step 119, the control unit 43 determines whether or not a predetermined end condition, for example, a condition such as the robot 10 moving to a designated position is satisfied, and if the end condition is not satisfied, the step Returning to 110, the robot 10 is driven by the speed command value Vcmd at that time, and if the termination condition is satisfied, the driving of the robot is terminated in step 120. When returning to step 110, the speed command value Vcmd up to that point and the speed command value Vcmd defined in step 116 or step 118 may be significantly different. In that case, control may be performed so that the moving speed changes gently. Also in the process shown in FIG. 6, the moving speed of the robot 10 is limited by the limit value Vlim determined based on the index L determined by the position of the tip of the robot 10, but in particular, it changes at any time according to the current position of the tip. Limited by the limit value Vlim.

7 and 8 show the results of simulating the movements of the arms 13, 15 and the hand 17 when the tip of the robot 10 is moved by 400 mm in the −Y direction, assuming the robot shown in FIG. Shown. In these figures, the angle toward the counterclockwise direction with respect to the Y-axis direction is positive, the azimuth angle of the tip of the arm portion viewed from the origin is θ1, and half of the angle formed by the first arm 13 and the second arm 15 is defined as θ1. It is set to θ2. FIG. 7 shows a case where the elbow of the robot 10 is closed to some extent (in other words, the tip is close to the origin O) and the XY coordinates of the tip of the arm portion 10 are (470,200) at the initial position. It shows the movement. FIG. 7 (a) shows the state at the initial position, FIG. 7 (b) shows the state in the middle of moving by -200 mm in the Y-axis direction, and FIG. 7 (c) shows the final state, that is, the XY coordinates of the tip. Indicates a state in which is (470, -200). On the other hand, FIG. 8 shows the movement when the elbow of the robot 10 is opened to some extent (the tip is far from the origin O) and the XY coordinates of the initial position of the tip are (1800,200). There is. FIG. 8A shows the state at the initial position, FIG. 8B shows the state in the middle of moving by −200 mm in the Y-axis direction, and FIG. 8C shows the final state, that is, the XY coordinates of the tip. Indicates a state in which is (1800, -200). In the one shown in FIG. 7, the movement of the elbow (the joint portion 13 between the first arm 13 and the second arm 15) is larger than the movement of the tip of the robot 10, which regulates the speed of the tip. It is not possible to sufficiently suppress the speed of movement of the elbow by itself. On the other hand, in the one shown in FIG. 8, the movement of the elbow is smaller than the movement of the tip. From FIGS. 7 and 8, when teaching, when the tip of the robot is close to the origin O, the robot is operated at a low speed, and when the tip is away from the origin O, the moving speed is set so that the robot can operate at a high speed. It can be seen that the restriction can prevent the elbow portion of the robot from moving at an unexpected speed for the teacher.

In the embodiment described above, by making the teaching pendant 40 function as a movement speed limiting device, it is not necessary to cause the robot controller to execute a process for limiting the moving speed based on the limit value. There is no risk of putting on. Further, since this movement speed limit is required only at the time of teaching, it is not necessary to incorporate the function for the movement speed limit into the robot controller. The parameter table itself required for the movement speed limit is stored in the robot controller in advance, and the parameter table is read into the teaching pendant when the teaching pendant 40 is connected. It becomes possible to execute using the same teaching pendant 40 for the robot. Alternatively, the parameter table for each robot model may be stored in the teaching pendant 40 in advance, and the parameter table may be selected according to the model when teaching.

The robot to which the present invention can be applied is not limited to the horizontal articulated robot having the first arm 13 and the second arm 15 shown in FIG. For example, a robot in which a telescopic joint is provided between the main body portion 11 and the connecting portion 12 so that the portion from the first arm 13 to the hand 17 can be moved up and down in the Z-axis direction in the same posture, or an XY plane. The present invention can also be applied to a robot in which a third arm that rotates inside is further provided at the tip of the second arm 15, a robot equipped with a tool that moves in the Z-axis direction in the hand 17. When applying the present invention to a robot moving in the Z direction, for example, the XYZ space is divided into several small spaces, and the moving speed is limited according to which small space the tip of the robot is in. You may do so.

10 ... Robot, 11 ... Main body, 12, 14, 16 ... Connecting, 13, 15 ... Arm, 17 ... Hand, 22, 24, 26 ... Motor, 30 ... Robot controller, 31 ... Robot drive, 32 ... Calculation Units, 33, 44 ... Auxiliary storage unit, 40 ... Teaching pendant, 43 ... Control unit, 50 ... Cable.

Claims (14)

A main body, a first arm whose one end side is connected to the main body, a first motor that rotates the first arm with respect to the main body, and a first arm whose one end is connected to the other end of the first arm. A movement speed control device for controlling a robot, which is a horizontal articulated robot, including at least two arms and a second motor for rotating the second arm with respect to the first arm.
The robot is controlled by the orthogonal coordinate system, and when teaching the robot, the robot is moved by using a different limit value determined based on the coordinates of the position of the tip of the robot on the second arm side in the orthogonal coordinate system. When the input instruction value for speed exceeds the limit value, the robot is moved by a movement speed that limits the input instruction value by the limit value, and the limit value based on the current position of the tip after movement is set. When the current movement speed of the robot is equal to or higher than the input instruction value and the current movement speed of the robot is lower than the input instruction value, a speed increase inquiry is made, and when an ascending instruction is input to the inquiry, the movement indicated by the input instruction value is performed. a control unit Before moving the robot by the speed, the moving speed control. Said one end of said first arm to the original point, a plane parallel to the movable range of the tip comprises said origin, is divided into a plurality of regions, and a single said limit value is defined for each of the regions The moving speed control device according to claim 1. The moving speed control device according to claim 2, wherein the region is a region defined by a square centered on the origin. The moving speed control device according to claim 2, wherein the region is a region defined by concentric circles centered on the origin. When the current moving speed exceeds the limit value based on the current position of the tip while the robot is moving, the control unit updates the moving speed of the robot by the limit value based on the current position of the tip. , The moving speed control device according to any one of claims 1 to 4. Wherein, during the period in which the continuation of operation to specify the movement of the robot, moving said robot by moving speed that is limited at the start of the period, the operation after the termination of the operation is resumed The moving speed control device according to any one of claims 1 to 4 , wherein the moving speed of the robot is limited based on the coordinates of the tip at the time of restarting. The movement speed control device is configured as a teaching pendant connected to the robot controller of the robot.
The teaching pendant has an auxiliary storage unit that stores a parameter table that describes the limit value according to the coordinates.
The moving speed control device according to any one of claims 1 to 6, wherein the control unit limits the input instruction value by using the limit value obtained by referring to the parameter table. The moving speed control device according to claim 7, wherein the parameter table is read from the robot controller into the auxiliary storage unit when the teaching pendant is connected to the robot controller. A main body, a first arm whose one end is connected to the main body, a first motor that rotates the first arm with respect to the main body, and a first arm whose one end is connected to the other end of the first arm. A method of controlling a robot, which is a horizontal articulated robot, including at least two arms and a second motor for rotating the second arm with respect to the first arm.
When the robot is controlled in the Cartesian coordinate system to teach the robot, different limit values determined based on the coordinates of the position of the tip of the robot on the second arm side in the Cartesian coordinate system are used. When the input instruction value for the movement speed exceeds the limit value, the robot is moved by the movement speed that limits the input instruction value by the limit value, and the limit value based on the current position of the tip after movement. Is equal to or greater than the input instruction value and the current moving speed of the robot is less than the input instruction value, an inquiry for speed increase is made, and when an increase instruction is input to the inquiry, the input instruction value indicates. mETHOD Before moving the robot by the moving speed. Wherein said one end of the first arm to the original point, a plane parallel to the movable range of the distal end including said origin is divided into a plurality of regions, defining a single of the limit value for each said region, claim 9. The method according to 9. The method according to claim 10, wherein the region is a region defined by a square centered on the origin. The method according to claim 10, wherein the region is a region defined by concentric circles centered on the origin. 9. To the robot, when the current moving speed exceeds the limit value based on the current position of the tip while the robot is moving, the moving speed of the robot is updated by the limit value based on the current position of the tip. The method according to any one of 12. During the period in which the continuation of operation to specify the movement of the robot, moving said robot by moving speed that is limited at the start of the period, when the operation after the termination of the operation is resumed, the The method according to any one of claims 9 to 12 , wherein the moving speed of the robot is limited based on the coordinates of the tip at the time of resumption.

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