Route determination device and numerical control device

Abstract

A route determination device according to one aspect of the present disclosure determines an escape route from a prohibited area in which entry of a movable part of an industrial machine is prohibited to a non-prohibited area in which entry of the movable part is not prohibited, and comprises: a candidate setting unit that sets a plurality of candidate routes serving as candidates for the escape route on the basis of the position of the movable part and the range of the prohibited area; and a route determination unit that determines the escape route from among the candidate routes by calculating evaluation values of the candidate routes on the basis of a preset evaluation criterion.

Description

Routing device and numerical control device

[0001] The present invention relates to a path determination device and a numerical control device.

[0002] For example, in industrial machinery such as robots and machine tools, a prohibited area may be set to prohibit the entry of a moving part such as a head. If a moving part enters the prohibited area, the industrial machinery may be stopped due to an error, but the operation of the moving part to leave the prohibited area may be permitted to prevent a decrease in the availability rate. For this reason, a technology has been proposed in which, if the current position of the moving part is within the prohibited area, the moving part to be controlled is moved in the direction of the movement command issued at that time, and a determination is made as to whether the moving part to be controlled will leave the prohibited area (see, for example, Patent Document 1).

[0003] Japanese Patent Application Publication No. 6-348327

[0004] The movement that allows the movable part to escape from the prohibited area can be extremely diverse. For example, if the prohibited area is an area surrounded by a non-prohibited area that does not prohibit the movable part from entering, the movable part can eventually escape from the prohibited area no matter which direction the movable part is moved in. For this reason, it is convenient to know a movement path that can efficiently allow the movable part to escape from the prohibited area.

[0005] A route determination device according to one aspect of the present disclosure is a route determination device that determines an escape route from a prohibited area in an industrial machine that prohibits the entry of moving parts to a non-prohibited area that does not prohibit the entry of the moving parts, and includes a candidate setting unit that sets multiple candidate routes as escape route candidates based on the position of the moving parts and the range of the prohibited area, and a route determination unit that determines the escape route from among the candidate routes by calculating an evaluation value of the candidate routes based on a predetermined evaluation criterion.

[0006] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be limited to the disclosed exemplary embodiments.

[0007]

[0023] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of an industrial machine 1 equipped with a numerical control device according to an embodiment of the present disclosure. In this embodiment, the industrial machine 1 is a machine tool equipped with a drive mechanism 10, a path determination device 20, and a numerical control device 30.

[0008] The drive mechanism 10 moves a movable part 11 such as a tool or a workpiece. As in the present embodiment, the drive mechanism 10 may be a Cartesian coordinate type drive mechanism having an X-direction drive shaft 12, a Y-direction drive shaft 13, and a Z-direction drive shaft 14, but is not limited to this and may have any configuration, such as a vertical articulated robot or a delta-type robot. Furthermore, depending on the configuration of the drive mechanism 10, the movement of the movable part 11 may be a relative movement with respect to another configuration.

[0009] 2 , in the industrial machine 1, when it is determined that the movable part 11 is present in a prohibited area Ar (area outside the dashed dotted line) in which entry of the movable part 11 is prohibited, the path determination device 20 determines an escape path Re for the movable part 11 from the prohibited area Ar to a non-prohibited area An (area inside the dashed dotted line) in which entry of the movable part 11 is not prohibited. The path determination device 20 itself is an embodiment of a path determination device according to the present disclosure.

[0010] The path determination device 20 may be realized by, for example, a single or multiple computer devices having a memory, a processor, an input / output interface, etc., and executing an appropriate control program. The path determination device 20 may be realized by an independent computer device, or may be integrated with the numerical control device 30 or another device. Specifically, the path determination device 20 may be realized as an additional function of a management computer that monitors the industrial machine 1, a server that provides information such as operating conditions to the industrial machine 1, or the like, and typically may be realized as an additional function of the numerical control device 30 that controls the drive mechanism 10.

[0011] The route determination device 20 includes a candidate setting unit 21, a route determination unit 22, and a notification unit 23. These components of the route determination device 20 categorize the functions of the route determination device 20, and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0012] The candidate setting unit 21 sets one or more, preferably multiple, candidate escape route candidates, Rn (n is a natural number), based on the current position Po of the movable part 11 and the range of the prohibited area Ar. The candidate routes Rn set by the candidate setting unit 21 preferably include one or more of the following: a route that reverses the route taken by the movable part 11 to move from the non-prohibited area An to the prohibited area Ar; a route that moves the movable part 11 linearly in the axis direction of a coordinate system that identifies the position of the movable part 11; a route that takes the shortest time to reach the non-prohibited area An; and a route that is the shortest in linear distance to the non-prohibited area An. Setting such typical routes as the candidate routes Rn makes it relatively easy to set the candidate routes Rn and facilitates the movable part 11 to escape from the prohibited area Ar along the finally determined escape route Re. The "coordinate system" that identifies the position of the movable part 11 is typically a coordinate system in which each axis coincides with the direction of the drive axes 12, 13, and 14 of the drive mechanism 10, but it may also be another coordinate system that the numerical control device 30 uses at least temporarily and that can be converted into and out of the coordinate system of the drive mechanism 10, such as a work coordinate system based on the orientation of the work.

[0013] Furthermore, the candidate route Rn set by the candidate setting unit 21 is not limited to a complete route connecting the current position Po of the movable part 11 and the outer edge of the prohibited area Ar as shown in Fig. 2, but may be set as a plurality of routes that can be drawn by setting a plurality of nodes within the prohibited area Ar through which the movable part 11 passes and connecting these nodes. Such nodes may be lattice points or square areas within the lattice that are set in an area that includes the entire prohibited area Ar, as shown in Fig. 3. By setting a large number of candidate routes using a plurality of nodes, a more appropriate escape route Re can be selected.

[0014] The route determination unit 22 determines an escape route Re from among the candidate routes Rn by calculating an evaluation value for the candidate routes based on predetermined evaluation criteria. The evaluation criteria preferably include one or more of the following: the degree of match with the previous movement path of the movable part 11; the total distance traveled by the movable part 11 until it reaches the non-prohibited area An; and the total travel time for the movable part 11 until it reaches the non-prohibited area An. Using such evaluation criteria allows the movable part 11 to quickly and reliably escape into the non-prohibited area An. Note that the drive speeds of the drive shafts 12, 13, and 14 may differ. In such cases, the evaluation may be based on the total distance traveled and the total travel time. The evaluation criteria may use any one of these values ​​as the evaluation value, or may use the calculated value of a formula that uses these multiple values ​​as variables.

[0015] Furthermore, when the candidate setting unit 21 sets candidate routes Rn using a plurality of nodes, the route determination unit 22 may use the partial evaluation values ​​between the nodes as values ​​calculated based on the total travel distance, total travel time, etc. As described above, when the evaluation values ​​between the nodes are not constant, the route determination unit 22 may calculate the evaluation values ​​using a breadth-first search algorithm such as the Dijkstra algorithm. By using such a well-known evaluation method, an appropriate escape route Re can be efficiently selected.

[0016] As a specific example, a case will be described with reference to FIG. 3 in which the movable part 11 moves linearly on the X-Y plane, candidate paths are set in the X-axis direction or the Y-axis direction, and the escape route Re is set as the path with the smallest total movement distance. The candidate setting unit 21 sets a plurality of nodes arranged in a grid pattern on the X-Y plane. The path determination unit 22 first sets a two-dimensional tensor (matrix) in which each element corresponds to one node and grids in the non-prohibited area An are represented by 1 and grids in the prohibited area Ar are represented by 0. If the values ​​of the matrix elements are represented as N(i,j) using row direction number i and column direction number j, and the initial values ​​of row direction number i and column direction number j are the numbers of the nodes corresponding to the current position Po of the movable part 11, then the value of the element N(i,j) is 0. Next, the process of checking the values ​​of the matrix elements N(i,j) is repeated until the value N(i,j) of the element at the position where i is added by 1 (i = i + 1) becomes 1. The difference between the value of row direction number i when the component value N(i, j) becomes 1 and the initial value of row direction number i is the total movement distance in the positive X-axis direction of the movable part 11 until it reaches the non-prohibited area An. Furthermore, when the value of row number i reaches the maximum row number of the matrix, it is determined that there is no path in the positive X-axis direction for the movable part 11 to reach the non-prohibited area An (lowest evaluation). Similarly, the total movement distance in the negative X-axis direction, the total movement distance in the positive Y-axis direction, and the total movement distance in the negative Y-axis direction can be calculated, and the path with the smallest total movement distance among these can be determined as the escape route Re.

[0017] In addition, if the direction of the escape route Re is not specified, the route determination unit 22 may repeatedly check the values ​​N(i, j) of the matrix components corresponding to multiple nodes whose cumulative evaluation value from the current position Po of the movable part 11 is constant, in order of decreasing cumulative evaluation value, and may determine the candidate route Rn whose component value N(i, j) first becomes 1 as the escape route Re.

[0018] The route determination unit 22 may use multiple evaluation criteria with a set priority order. Specifically, when the route determination unit 22 cannot narrow down the candidate routes Rn to one using the evaluation criteria with a higher priority order, the route determination unit 22 may be configured to select the candidate route Rn with a higher evaluation score based on the evaluation criteria with the next highest priority order as the escape route Re from among the candidate routes Rn with a higher evaluation score based on the evaluation criteria with the next highest priority order. This allows for a complex judgment using multiple relatively simple evaluation criteria, making it possible to select an appropriate escape route Re relatively easily.

[0019] The notification unit 23 notifies other devices, such as the numerical control device 30, of the escape route Re determined by the route determination unit 22. This allows the numerical control device 30 to automatically control the drive mechanism 10 to move the movable part 11 along the escape route Re and cause the movable part 11 to escape from the prohibited area Ar to the non-prohibited area An. Furthermore, if the notification unit 23 is unable to narrow down the candidate routes Rn to one, the notification unit 23 may be configured to present the remaining highly rated candidate routes Rn to the user and ultimately determine one escape route Re based on the user's selection. Therefore, the device used by the notification unit 23 to notify the user may be an alarm device, such as a rotating light or buzzer, that notifies the user.

[0020] The numerical control device 30 controls the drive mechanism 10. The numerical control device 30 also passes position information of the movable part 11 to the path determination device 20 and changes the control of the drive mechanism 10 in response to a notification from the notification unit 23. The numerical control device 30 may be configured to include a program control unit 31, a movement prohibition unit 32, and an escape execution unit 33. The numerical control device 30 may be realized by one or more computer devices that have, for example, a memory, a processor, an input / output interface, etc. and execute appropriate control programs. The above-mentioned components of the numerical control device 30 are merely classifications of the functions of the numerical control device 30 and may not be clearly distinguishable in terms of physical configuration and program configuration.

[0021] The program control unit 31 controls the operation of the drive mechanism 10 in accordance with the work program, and causes the drive mechanism 10 to perform operations such as machining intended by the work program. The configuration of the program control unit 31 can be the same as that of a conventional numerical control device.

[0022] The movement prohibition unit 32 prohibits the movable part 11 from moving along a path different from the escape route Re determined by the path determination unit 22. This prevents the movable part 11 from moving around inside the prohibited area Ar and interfering with other components. The movement prohibition unit 32 may permit the movable part 11 to move along a path that is within a certain error range, rather than just a path that completely matches the escape route Re. This improves the possibility that the program control unit 31 can continue operation without causing any problems.

[0023] The escape execution unit 33 controls the drive mechanism 10 to move the movable part 11 along the escape route Re determined by the route determination unit 22. The escape execution unit 33 may be configured to interrupt the control by the program control unit 31, cause the movable part 11 to escape into the non-prohibited area An, and then resume control by the program control unit 31. In this way, by providing the escape execution unit 33 that automatically causes the movable part 11 to escape along the escape route Re, it is possible to more effectively prevent problems such as the movable part 11 interfering with other components while completing the control by the program control unit 31.

[0024] As described above, the path determination device 20 determines an escape path Re that allows the movable part 11 to efficiently escape from the prohibited area Ar to the non-prohibited area An, thereby more reliably preventing problems such as interference with the movable part 11.

[0025] The following supplementary notes are further disclosed regarding the above-described embodiment and modified examples. (Supplementary Note 1) A route determination device (20) determines an escape route from a prohibited area, which prohibits the entry of a movable part (11), to a non-prohibited area, which does not prohibit the entry of the movable part (11), in an industrial machine (1), and includes a candidate setting unit (21) that sets a plurality of candidate routes that are candidates for the escape route based on the position of the movable part (11) and the range of the prohibited area, and a route determination unit (22) that determines the escape route from the candidate routes by calculating an evaluation value of the candidate route based on a preset evaluation criterion.

[0026] (Supplementary Note 2) In the route determination device (20) of Supplementary Note 1, the multiple candidate routes may include one or more of a route that reverses the route that the movable part (11) took to move from the non-prohibited area to the prohibited area, a route that moves the movable part (11) in a straight line in the axial direction of a coordinate system that identifies the position of the movable part (11), a route that takes the shortest time to move to the non-prohibited area, and a route that has the shortest straight-line distance to the non-prohibited area.

[0027] (Supplementary Note 3) In the path determination device (20) of Supplementary Note 1 or 2, the evaluation criteria may include one or more of the degree of match with the past movement path of the movable part (11), the total movement distance of the movable part (11) until it reaches the non-prohibited area, and the total movement time of the movable part (11) until it reaches the non-prohibited area.

[0028] (Supplementary Note 4) In the route determination device (20) of any one of Supplementary Notes 1 to 3, the route determination unit (22) may use a plurality of evaluation criteria with a set priority order.

[0029] (Supplementary Note 5) The route determination device (20) of any one of Supplementary Notes 1 to 4 may further include a notification unit (23) that notifies the user of the escape route determined by the route determination unit (22).

[0030] (Supplementary Note 6) A numerical control device (30) that controls an industrial machine (1) and includes the route determination device (20) of any one of Supplementary Notes 1 to 5, and includes a movement prohibition unit (32) that prohibits the movement of the movable part (11) along a route different from the escape route determined by the route determination unit (22).

[0031] (Supplementary Note 7) The numerical control device (30) of Supplementary Note 6 may further include an escape execution unit (33) that moves the movable unit (11) along the escape route determined by the route determination unit (22).

[0032] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these.

[0033] REFERENCE SIGNS LIST 1 Industrial machine 10 Drive mechanism 11 Movable part 20 Path determination device 21 Candidate setting unit 22 Path determination unit 23 Notification unit 30 Numerical control device 31 Program control unit 32 Movement prohibition unit 33 Escape execution unit An Non-prohibited area Ar Prohibited area Re Escape route Rn Candidate route

Claims

1. A route determination device for determining an escape route from a prohibited area in an industrial machine that prohibits the entry of moving parts to a non-prohibited area that does not prohibit the entry of the moving parts, comprising: a candidate setting unit that sets multiple candidate routes to be escape route candidates based on the position of the moving parts and the extent of the prohibited area; and a route determination unit that determines the escape route from among the candidate routes by calculating an evaluation value of the candidate routes based on a preset evaluation criterion.

2. The path determination device of claim 1, wherein the plurality of candidate paths include one or more of the following: a path that reverses the path that the movable part took to move from the non-prohibited area to the prohibited area; a path that moves the movable part in a straight line in the axis direction of a coordinate system that identifies the position of the movable part; a path that takes the shortest time to move to the non-prohibited area; and a path that has the shortest straight-line distance to the non-prohibited area.

3. A path determination device as described in claim 1 or 2, wherein the evaluation criteria include one or more of the following: the degree of match with the past movement path of the movable part; the total movement distance of the movable part until it reaches the non-prohibited area; and the total movement time of the movable part until it reaches the non-prohibited area.

4. A route determination device according to any one of claims 1 to 3, wherein the route determination unit uses a plurality of evaluation criteria with a set priority.

5. A route determination device according to any one of claims 1 to 4, further comprising a notification unit that notifies the user of the escape route determined by the route determination unit.

6. A numerical control device that controls industrial machinery and is equipped with a route determination device according to any one of claims 1 to 5, and that is equipped with a movement prohibition unit that prohibits movement of the movable part along a route different from the escape route determined by the route determination unit.

7. The numerical control device according to claim 6, further comprising an escape execution unit that moves the movable unit along the escape route determined by the route determination unit.

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