JP2017107432A - Production performance evaluation device of machine system and production performance evaluation method of machine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production performance evaluation device of a machine system capable of performing a machine system design at high efficiency.SOLUTION: A production performance evaluation device includes: state transition definition means 11 for defining a state transition probability and an operation time between component states with respect to the component state defined by a position or an attitude which the component could take before and after the work process of a machine system; and route extraction means 12 for extracting a transition route from an initial state to a target state on the basis of the state transition probability and the operation time. The production performance evaluation device further includes: route cycle time calculation means 13 for calculating a route cycle time which is an expectation value of the time required for transiting between the component states for the route from the state transition probability and the operation time; and expectation tact time calculation means 14 for calculating an expectation tact time which is a time required for one component to become a target state by a machine system from the transition route extracted by the route extraction means 12.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a machine system production performance evaluation apparatus and a machine system production performance evaluation method for analyzing production performance in a machine system that automatically performs product production.

  The productivity of a production system consisting of multiple mechanical systems should be evaluated by the production system designer based on the production volume, the area occupied by the mechanical system, the mechanical system failure rate, and the required investment amount to improve productivity. Determine the possible configurations. As a means to automatically perform these evaluations, the capacity of the production equipment to be applied is defined, the production efficiency is calculated based on the defined capacity, and the problematic production equipment is transferred to another production equipment. Patent Document 1 proposes a production efficiency evaluation method for switching comparison examination.

JP-A-8-77247

  In recent years, due to changes in demands on production systems, there is an increasing need to handle various types of parts in one production system. For this reason, designing a mechanical system based on the premise that “no failure will occur” as in the past would result in a complicated design and a dedicated machine. There is a problem that you can not. On the other hand, by utilizing sensors such as vision sensors and force sensors for mechanical systems, it is possible to handle a wide variety of parts in the same system and to absorb positioning errors that occur in production equipment. Mechanical systems that can do this have been proposed.

  In such a mechanical system, it is possible to construct a configuration in which a working state is recognized and automatically recovered using a sensor even in a state where an error has occurred in the past, such as failure in gripping an object. As a result, a simple robot production facility that eliminates the positioning device and jig for the target component (workpiece) can be configured.

  However, it is difficult to apply a conventional productivity evaluation method to such a mechanical system. For example, conventionally, a machine system or worker is defined as each production facility by a failure rate or work efficiency, and attention has been paid to whether or not the arrangement satisfies the tact time as a required specification. On the other hand, in a system that allows error states and failures and automatically recovers, the tact time cannot be predicted by simply accumulating cycle times in order to allow failures. In other words, it is difficult to quantitatively predict how much production performance actually has even when continuously operating by the conventional evaluation method.

  Further, if the production target value for the mechanical system is quantitatively calculated based on the conventional evaluation method, it is necessary to improve the mechanical system that realizes the production target value. In this case, the frequency of failure for each operation should be improved, but it has been difficult to quantitatively express the design improvement target value inside the mechanical system.

  The present invention has been made in view of the above, and in a mechanical system that can tolerate error states and failures and can be automatically restored, to quantitatively calculate production performance and to study design improvements It is an object of the present invention to obtain a machine system production performance evaluation apparatus that can perform a machine system design with high efficiency by presenting the calculation result to.

  In order to solve the above-described problems and achieve the object, the present invention provides a state transition probability between component states with respect to a component state defined by positions or postures that the component can take before and after the work process of the mechanical system. State transition defining means for defining work time, and path extracting means for extracting a transition route from the initial state to the target state based on the state transition probability and the work time. Further, a route cycle time calculating means for calculating a route cycle time, which is an expected value of the time taken for transition between component states, with respect to the route from the state transition probability and the work time, a route cycle time, a route And an expected tact time calculating means for calculating an expected tact time that is a time required for one component to reach a target state in the mechanical system from the transition path extracted by the extracting means.

  According to the machine system production performance evaluation device of the present invention, in a machine system that can tolerate error states and failures and can be automatically restored, the production performance can be quantitatively calculated and design improvement can be studied. By presenting the result of the calculation, the mechanical system can be designed with high efficiency.

The figure which shows the structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 1 of this invention. The figure which shows the mechanical system evaluation apparatus using the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 1. FIG. The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 1. FIG. The figure which shows the operation | movement of a robot and state transition diagram in Embodiment 1 in association with each other The figure which shows the operation | movement of a robot and state transition diagram in Embodiment 1 in association with each other The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 2. FIG. The figure which shows the other example of a function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 2. FIG. The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 3. FIG. The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 4. FIG. The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 5. FIG. The figure which shows the function structure of the production performance evaluation apparatus of the mechanical system which concerns on Embodiment 6. FIG. The figure which shows the hardware constitutions of the production performance evaluation apparatus of a mechanical system

  A machine system production performance evaluation apparatus and a machine system production performance evaluation method according to an embodiment of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a production performance evaluation apparatus for a mechanical system according to Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating a mechanical system evaluation apparatus using the mechanical system production performance evaluation apparatus according to the first embodiment. First, processing contents of the production performance evaluation apparatus 1 for a mechanical system according to Embodiment 1 and definitions of terms used in the following description will be described.

  As shown in FIG. 1, the production performance evaluation device 1 of a mechanical system is a device that receives state transition information 101 and outputs production performance information 102. In FIG. 2, a mechanical system having a robot 2 and a conveyor 3 as constituent elements is taken as an example of a mechanical system whose production performance is evaluated by the production performance evaluation apparatus 1 of the mechanical system. Each component is controlled by the controller 4. Whether each operation of each component has been successful is acquired by using the vision sensor 2c provided in the robot 2 as to whether or not the work target has been put in a desired state as a result of the work of the mechanical system. It is determined by doing. The machine system data including information on whether or not the operation is successful is managed by the information integration device 5. Note that the information integration device 5 refers to a device that can determine the state by using various input information such as a programmable logic controller such as a sequencer in an integrated manner and determines the next processing. .

  In particular, two pieces of data that are state transition information 101 are extracted from the mechanical system data. The first data extracted is the state transition probability. The state transition probability is data obtained from the total number of operations and the success or failure of the operation, and indicates the frequency of occurrence of the component state during the operation. The second data to be extracted is the work time per time.

  These two data are input to the production performance evaluation apparatus 1 of the mechanical system mounted on the personal computer, and the production performance information 102 calculated by the production performance evaluation apparatus 1 of the mechanical system is displayed on the display device 6. However, as a system provided by the present invention, the mounting position of the vision sensor 2c is not limited to the position shown in FIG.

  Here, in the machine system data, based on the design information of the machine system, the contents of work performed in the machine system, the context of each work content, the time required for each work, the state transition of the position and orientation of parts in each work Probability is included. The time required for each work is called a work time. Further, the state transition information 101 indicates the state transition probability, the context of each work content, and the work time.

  A possible state and a state to be distinguished are defined as a “component state”, including a state in which a part to be worked is in a stable posture and a state in which it is unstable. In the mechanical system, it is described by a model in which the robot 2 or the automatic machine changes the state of a component and changes the “component state” to a desired position and orientation.

  For example, when considering the “component state” of a dice, the dice eye is a criterion for distinguishing the component state. That is, it can be defined that there are six “component states” in the dice by distinguishing whether the surface showing any number of dice eyes 1 to 6 is visible on the upper surface. Furthermore, when a specific position and posture are reached, it may be difficult to continue the work. A component state is also defined in such a state, and is defined as one of the entire component states. At this time, for example, in the case of a dice, the posture is the same as that of the component states 1 to 6 in the component state where it is difficult to continue the operation, but when it is in a position outside the robot movable range or attached to the robot This includes a case where it is difficult to continue the work because it faces a direction that cannot be gripped by the end effector. Such a component state that is difficult to continue is defined as belonging to the seventh “component state”.

  Next, when the robot 2 or the mechanical system operates a part to change the position and orientation, this operation is called “work”. The time taken to process one work is called “work time”. At this time, the working time may be variable. In the following description, it is assumed that the work is processed in a certain time, that is, the “work time” is constant.

  Here, in the component states defined by a finite number, the ratio of the transition between the component state before execution of a certain operation and the component state after execution of a certain operation is considered. In other words, the state transition probability is defined as the part state that was taken after a certain amount of production processing was performed as a state transition between part states that occurred through work and divided by the total number of production processes. . In the case of a dice, for example, it is the “state” that indicates how much the work that has been changed from a state in which the dice eye is 1 to a state in which the dice eye is 2 is performed with respect to the total number of trials of the work. It is defined as one of “transition probabilities”.

  The state transition probability is defined for each part. At the design stage, the machine system determines the number of parts that have entered each part state based on the actual production volume of work processes performed in other mechanical systems in the past. It can be determined by the value divided by the total number of parts worked on.

  Next, the configuration of the production performance evaluation apparatus for the machine system according to the first embodiment and the production performance evaluation procedure will be described with reference to FIGS. FIG. 3 is a diagram illustrating a functional configuration of the production performance evaluation apparatus for the mechanical system according to the first embodiment. 4 and 5 are diagrams showing the operation of the robot 2 and the state transition diagram in the first embodiment in association with each other. In the example shown in FIG. 4 and FIG. 5, it is shown that the operation 1 that is the operation of taking out the components takes 5 seconds, and the operation 2 that aligns the extracted components takes 10 seconds.

  First, in the state transition defining means 11 shown in FIG. 3, the work performed by the machine system is the work W1 as the first work, the work W2 as the next work, and the kth work as the work performed in the machine system. It is assumed that the work Wk (k = 1, 2,... N). A component state of a certain component is defined as a component state Si (i = 1, 2,..., M). Further, a probability that another part state Sj is generated from a part state Si having the work Wk is a state transition probability P (Si; Wk; Sj). It is assumed that the component state and the next component state are exhaustively connected, but the state transition probability (Si; Wk; Sj) = 0 is set for those in which state transition cannot occur.

  Based on these, all the component states that can be taken before and after the work Wk are defined for the target mechanical system. At this time, if a state where it is difficult to continue the operation occurs, this is defined as one state. Next, the state transition probability P (Si; Wk; Sj) between the component states that can be taken before and after the work, and the time taken to perform the work Wk once are defined as the work time T (Wk).

  Since the time required for one operation can be defined as fixed in an automatic device, for the sake of simplicity, it is assumed here that one operation is always performed at the same time without depending on the component state. . However, when the work execution time varies depending on the part state Si when the work Wk is performed, the part time is defined as the work time T (Si; Wk; Sj). It can also be defined in a form dependent on.

  Information indicating the state transition probability 103 and work time 104 and their connection relationship, that is, the information representing the state transition diagram shown in FIG. 4 is input to the route extracting means 12 shown in FIG. The state transition information 101 is also input to the route cycle time calculation unit 13. The route extraction unit 12 performs a process of extracting a route that can reach a state that can be counted as a production amount. The extracted route information 105 is input to the route cycle time calculation means 13. First, in the mechanical system, all the component states in the first work are set to the initial state. In addition, a component state that is in a work completion state in the mechanical system is set as a target state. That is, the state in operation 1 is called an initial state, and the state in operation N is called a target state. The paths that can reach the target state from the initial state are all transition paths that reach the target state in the work N from the component state that can occur in the work 1. The process of extracting all the transition paths is a process of extracting a path that can reach a state that can be counted as a production amount.

In the route cycle time calculation unit 13 shown in FIG. 3, the route cycle time Tr (Si; Wk; Sj) 106 is changed in state transition for each of all routes obtained from the route information 105 input from the route extraction unit 12. The calculation is performed by Expression (1) using the probability 103 and the work time 104.
Tr (Si; Wk; Sj) = T (Wk) / P (Si; Wk; Sj) (1)
Note that “/” in equation (1) represents division.

The calculated path cycle time 106 is input to the expected tact time calculation means 14. The expected tact time calculation means 14 uses the route cycle time 106 as the processing capacity obtained by summing up the production efficiencies of all the extracted routes, and the expected tact time is the time taken to reach the target state per part. It outputs as 107. An example of the definition of the expected tact time 107 is shown below. First, in order to obtain the expected number of processes for each route, a route tact time that is an expected tact time for each route is calculated. By simply adding the route cycle times, for example, the route tact time Tr sum (l) (l = 1, 2,... Nl, where Nl is a natural number) can be defined as follows. Since l means a route, if there are N routes that reach the target state, Nl = N.
Tr sum (l) = Tr (Si1; W1; Sj1) + Tr (Si2; W1; Sj2) +... + Tr (Si _N ; W _N ; Sj _N ) (2)
However, n is a natural number of 3 or more. Also, since one route l is targeted, when a part state Sj with a work Wk is placed in the next work Wk + 1 and starts with a part state Si, two states, that is, Sjn-1 is equal to Sin. warn.

  The reciprocal number of each route cycle time Tr sum (l) (l = 1, 2,..., Nl) of all routes obtained as the route tact time Tr sum (l) for each route is expected for each route. This is expressed as the expected production number Nrsum per unit time of the route, which is the production number per unit time.

In other words, the expected tact time is in units of [seconds / piece], but when the tact time between routes is added together, the expected per unit time of the route representing the production amount is not a simple sum of time. The expected production amount Nest added after the conversion into the expression of the production number Nrsum (l) [pieces / second] is calculated. In general, “tact time” is expressed by production time / production amount, but in the present invention, it is defined as production time / production amount in a mechanical system.
Nest = Σ Expected number of production per unit time of route Nrsum (l) (3)

Further, the expected tact time Test is calculated by taking the reciprocal of the expected production amount Nest.
Test = (1 / Nest) (4)
With the above procedure, the expected tact time can be calculated.

  Here, as an example of a specific change amount calculation method, a change amount calculation method in the case shown in FIG. 4 will be described. In FIG. 4, a mechanical system using two robots 2 (2a, 2b) is configured, and each robot 2 performs one work.

  As the work contents, the robot 2a performs the bin picking work as the first work W1, and the robot 2b performs the part aligning work for grasping and aligning the bin picked parts as the second work W2. The parts when the robot 2a completes the work are installed on a table called a temporary table, and the robot 2b picks up the parts from the temporary table and aligns the parts.

  Each operation by the robots 2a and 2b is assumed to be performed in a certain time, and is defined as T (W1) = 5 seconds and T (W2) = 10 seconds. That is, this means that the operation W1 is performed once and parts are supplied to the next process every 5 seconds, and the operation W2 is performed in the subsequent process and the alignment completion product appears every 10 seconds.

  A mechanical system in which the robots 2a and 2b are arranged so that these processes are performed in series will be described as an example. At this time, the parts to be aligned have, for example, six stable postures such as dice, and can assume six posture states in any work.

  Since there are various states of parts in the initial state of bin picking, there are states of i = 1, 2, 3, 4, 5, 6 as the initial state Si (k = 1).

  Next, when the robot 2a completes the bin picking work, seven of j = 1, 2, 3, 4, 5, 6, and 7 are defined as Sj (k = 1) that can be taken by the temporary table. Is done. j = 7 represents a failure state. The failure state belongs to any posture of j = 1 to 6, but is in a state where it is difficult to continue the work, and represents a component state to be dealt with by line-out or the like.

  The state transition probabilities of the state transition to the temporary table by the bin picking work are P (Si, W1, S1) = 0.4, P (Si, W1, S2) = 0.3, P (Si, W1, S3). ) = 0.1, P (Si, W1, S4) = 0.05, P (Si, W1, S5) = 0.05, P (Si, W1, S6) = 0.05, P (Si, W1) , S7) = 0.15. However, Si includes all states, and such a definition is made when the initial state such as bin picking is not clearly understood.

  Further, as described later, when the state moved to the temporary placement table is a state other than the state S1 and the state S2, a part state in which parts cannot be arranged as the next operation is set. Therefore, a plurality of component states in which component alignment cannot be performed are collected as one state. Therefore, the state transition probability actually handled is P (Si, W1, S1) = 0.4, which transitions from the initial state to state 1, and P (Si, transitions from the initial state to state 2, as shown in FIG. , W1, S2) = 0.3, and three state transition probabilities of P (Si, W1, S3, S4, S5, S6, S7) = 0.4, which transition from the initial state to state 3, are summarized.

  The part state in which parts cannot be arranged means a part state in which an operation for changing the front and back of the part state is taken out from the temporary placement table by the robot that performs the part alignment operation. In this case, the line-out is performed without performing the parts alignment operation itself. Line-out refers to removing a part, work-in-process, or product that is subject to line-out from the production line once there are defective products or some problems while people or machines work on the production line. Yes.

  Next, with respect to the component alignment work by the robot 2b, it is assumed that the state Si (k = 2) before alignment is only i = 1, 2 and that the components cannot be aligned from other states. That is, it is assumed that component alignment cannot be performed when the state is other than i = 1 or 2. In this case, the state transition includes three states including two i = 1, 2 and i = 3,4,5,6 and one of the failed states (exceptional states such as missed and line-out). I can think.

  When the component alignment completion posture is set to i = 1, among these three states, the state transition probability P (S1, W2, S1) = 0.7, P (S2, W2) for the state of i = 1, 2 , S1) = 0.3. State transition does not occur from i = 3, 4, 5, 6 and a state where it is difficult to continue the operation (exceptional state such as missing and line-out), so P (S3, S4, S5, S6, S7, W2) , S1) = 0.0.

In such state transition, there are two paths that can reach the target state. The route 1 has a route of state Si → S1 → S1 and Tr sum (1), and the route 2 has a route of Si → S2 → S1 and Tr sum (2). For each path, Tr (Si; Wk; Sj) = T (Wk) / P (Si; Wk; Sj) is obtained, and Tr sum (1) and Tr sum (2) are obtained.
Tr (Si; W1; S1) = T (W1) / P (Si; W1; S1) = 5 / 0.4 = 12.5
Tr (S1; W2; S1) = T (W2) / P (S1; W2; S1) = 10 / 0.7 = 14.3
Tr sum (1) = Tr (Si; W1; S1) + Tr (S1; W2; S1) = 26.8
Tr (Si; W1; S2) = T (W1) / P (Si; W1; S2) = 5 / 0.3 = 16.7
Tr (S2; W2; S1) = T (W2) / P (S2; W2; S1) = 10 / 0.3 = 33.3
Tr sum (2) = Tr (Si; W1; S2) + Tr (S2; W2; S1) = 50.0
It becomes.

From the above results, when calculating the expected production amount Nest and the expected tact time Test,
Nest = Σ [1 / (Trsum (l))] = (1 / 26.8 + 1 / 50.0) = 0.0573
Test = 1 / Nest = 1 / 0.0573 = 17.5
It becomes.

  In the above calculation, the expected tact time is calculated as 17.5 [seconds / piece] (see also FIG. 5). In the first embodiment, the production performance information 102 output from the production performance evaluation apparatus for the mechanical system shown in FIG. 1 is the expected tact time.

  As described above, the machine system production performance evaluation apparatus 1 calculates the path cycle time based on the work time in each work and the state transition probability of the component state when each work is performed. Since the expected tact time is calculated from the determined path cycle time, the path cycle time and the expected tact time can be displayed to the system designer as the production performance of the mechanical system. In other words, the ability to quantify the production performance of a mechanical system that can be tolerated automatically and allowed to recover can be used to determine whether the mechanical system has the productivity required by the designer. . Therefore, it is possible to shorten the examination time in the concept design and modification design stages.

  Up to this point, the method of calculating the sum of the route tact time (the reciprocal of the expected number of productions Nr [unit / second] per unit time of the route) between each operation has been introduced. is there. Specifically, the following procedure is used to calculate the expected production number Nrsum per unit time of the direct route.

  First, paying attention to a certain route l, the route cycle time Tr (Si1; W1; Sj1) at the head of the route is compared with the work time T (W2) of the next process. If the work time T of the next process is smaller, it is assumed that the rate-limiting step of the process is in the process W1, and first, the production quantity per work unit is Nr (Si; Wk; Sj) = 1 / Tr (Si; Wk; Sj).

The production efficiency after that is defined as follows depending on the state transition probability P (Si; Wk; Sj) of the subsequent process.
Nrsum (l) = Tr (Si1 ; W1; Sj1) * P (Si2; W2; Sj2) ··· * P (Si N; W N; Sj N) ··· (5)
However, n is a natural number of 3 or more. * Is a symbol representing multiplication.

In the size comparison, if the subsequent process is large, the next process (W2 work in this case) is replaced with the work at the head, and the path cycle time Tr (Si2; W2; Sj2) is obtained and similarly compared. This is repeated until the working time becomes smaller. In the case where repeated until the final work, Nrsum (l) = Tr is defined as _{(Sin; Sjn; W N)} . Subsequent processing can calculate Nest as described above.

Embodiment 2. FIG.
FIG. 6 is a diagram illustrating a functional configuration of the production performance evaluation apparatus for the mechanical system according to the second embodiment. In the second embodiment, in order to satisfy the takt time of the entire production system, when the target takt time of the mechanical system to be evaluated is determined, the design time for satisfying the target takt time can be shortened. it can. In addition, the same code | symbol is attached | subjected about the component similar to the said Embodiment 1, and the overlapping description is abbreviate | omitted.

  The state transition change amount calculation means 21 shown in FIG. 6 compares the expected tact time (Test) 107 obtained by the expected tact time calculation means 14 described in Embodiment 1 with the target tact time (Tdes) 201. When the target tact time 201 is larger, the change amount of the state transition probability and the work time is set to 0, the change amount is added to the state transition information 101, and the state transition information 202 is based on the state transition change amount. The data is output and stored in the work time / state transition probability storage means 22. The design change information indicates a change amount of at least one of the state transition probability and the work time of each component state. The design change information is output as a part of the production performance information 102 shown in FIG. 1 and is information for presenting the designer that the design change is not required.

  On the other hand, the expected tact time (Test) 107 obtained by the expected tact time calculation means 14 is compared with the target tact time (Tdes) 201. If the target tact time (Tdes) 201 is smaller, the expected tact time (Tdes) 201 is smaller. Since the time does not reach the target tact time, the amount of change in the state transition information necessary to make the expected tact time reach the target tact time is calculated.

  Here, considering a specific example of the same conditions as in the first embodiment, the expected tact time is calculated as 17.5 [seconds / piece]. Here, when the target tact time is 16.5 [seconds / piece], the state transition change amount calculating means 21 changes the state transition information 101 necessary for realizing the target tact time by some methods. Is calculated. Specifically, a change amount of at least one of the state transition probability and the work time which is the state transition information 101 is calculated.

  When only the state transition probability is changed, the target tact time is increased by increasing the state transition probability of P (S1, W2, S1) or P (S2, W2, S1) when performing the part alignment work from the temporary table. Here are some candidate routes that can achieve: Here, weighting that the improvement of the work success rate of parts alignment is more effective than the improvement of raising the work success rate of various bin picking due to the change of the part state and the part state due to gripping. .

  Here, as an example, when each of P (S1, W2, S1) and P (S2, W2, S1) is changed independently, the one with the smallest amount of change is selected.

  At this time, when the state transition probability of P (S1, W2, S1) is improved to 0.8, the expected tact time is 16.7 [seconds / piece], and the state of P (S2, W2, S1) When the transition probability is improved to 0.4, 16.3 [seconds / piece] is obtained. The state transition change amount calculating means 21 outputs that the minimum change amount is selected and the state transition probability of P (S2, W2, S1) is improved by 0.1 to 0.4. However, the determination method of the state transition change amount can be redefined by the user by determining the priority order and the evaluation function according to the purpose. Therefore, it is not restricted to this method.

  FIG. 7 shows a configuration that does not include the working time / state transition probability storage means 22, but the state transition information 202 based on the state transition change amount output by the state transition change amount calculation means 21 is not stored once. The same effect is exhibited with the configuration of FIG. When the work time / state transition probability storage means 22 is included, it is possible to select a work time / state transition probability selectively from the past history and compare the results.

  By applying a machine system production performance evaluation device that performs the above processing, the designer can shorten the period of design improvement that satisfies the target tact time, which is the target specification, in a short time. it can.

Embodiment 3 FIG.
FIG. 8 is a diagram illustrating a functional configuration of the production performance evaluation apparatus for the mechanical system according to the third embodiment. In the third embodiment, when the target tact time of the machine to be evaluated is determined in order to satisfy the tact time of the entire production system, it can be specifically exchanged as a design change means for satisfying the target tact time. By limiting the number of devices, the examination time can be further reduced as compared with the configuration of the second embodiment. In addition, the same code | symbol is attached | subjected about the component similar to the said Embodiment 1 and Embodiment 2, and the overlapping description is abbreviate | omitted.

  The device selection unit 31 shown in FIG. 8 can output, as device information 301, information on a device that can be replaced based on device information registered as a design option registered in advance. Here, the device information 301 specifically includes the shape of the fingertip of the robot hand and the product type of the robot hand regarding points related to the work of grasping the object. In addition, as a method of conveying and supplying an object, it refers to a device that can be replaced in order to transition an object to a target state in a mechanical system, such as a parts feeder or a belt conveyor. The device selection unit 31 registers the state transition probability 103 and the work time 104 in advance in the work time / state transition probability storage unit 22 for each possible combination of devices for each target operation. For each combination, it is possible to specify the device information 301 in accordance with the designer's instruction, and switch the state transition information 101 in the state transition definition means 11 to output it.

  The state transition definition unit 11 can calculate the path cycle time 106 and the expected tact time 107 in each device configuration using the state transition probability 103 in the device specified according to the device information 301.

  With the above configuration, the system designer can easily compare and examine the path cycle time and expected tact time for each assumed device configuration, so the machine system can meet the target tact time, which is the target specification, in a short time. Design improvement can be completed in a short period of time.

Embodiment 4 FIG.
FIG. 9 is a diagram illustrating a functional configuration of the production performance evaluation apparatus for the mechanical system according to the fourth embodiment. In the fourth embodiment, not only the takt time of the entire production system is satisfied, but also the cost due to the constituent devices can be evaluated. By evaluating the target takt time of the machinery and equipment, and satisfying the target takt time and satisfying the initial investment and operation cost of the equipment when the target cost of equipment configuration is established. Can be designed. With the configuration of the fourth embodiment, the rework due to the fact that the cost for constructing and operating the mechanical system does not satisfy the target cost is reduced, so that the design time can be further shortened. In addition, the same code | symbol is attached | subjected about the component similar to the said Embodiment 1-3, and the overlapping description is abbreviate | omitted.

  The state transition information 101 is input from the state transition definition unit 11 to the cost calculation unit 41 shown in FIG. Device information 401 is input from the device selection unit 31 to the cost calculation unit 41. The cost calculation unit 41 calculates a cost based on the state transition information 101 and the device information 401.

  Here, the device information 401 includes the procurement cost of the device alone, the start-up cost related to the device, the life of the device, the replacement part replacement frequency and the cost required for the device maintenance, and the operation cost including the power consumption. Contains. The cost calculation unit calculates the device operation cost information 402 from the device information 401, the state transition information 101, the device investment calculated based on the period during which the mechanical system is operated, and inputs the device operation cost information 402 to the state transition change amount calculation unit 21. .

  The state transition change amount calculation means 21 compares the target cost 403 with the equipment investment and equipment operation cost information 402, and when the equipment investment and equipment operation cost information 402 becomes larger than the target cost 403, the state transition change amount calculation means 21 The other device information 301 is output and input to the state transition definition unit 11. For example, when the equipment investment and equipment operation cost information 402 becomes larger than the target cost 403, the state transition probability 103 is deteriorated by changing the design partly such as simplifying the fingertip shape of the robot hand with the same equipment configuration. However, when the cost can be reduced, the definition of the device information 301 in the device selection means 31 can be considered in the same manner by treating it as another configuration even when the device itself is not changed.

  With the above configuration, when the target tact time of the machine is determined, the target tact time is satisfied, and when the target cost of the device configuration is determined, the initial investment and operation cost of the device are satisfied. By evaluating the above, it is possible to further shorten the design time as compared with the third embodiment.

Embodiment 5. FIG.
FIG. 10 is a diagram illustrating a functional configuration of a production performance evaluation apparatus for a mechanical system according to the fifth embodiment. In the fifth embodiment, a configuration is further added to the fourth embodiment in which a part state defined as being difficult to continue by the state transition defining unit 11 is redefined as being able to continue working. is there. As described above, when the means of increasing the state transition can be evaluated, the configuration of the fifth embodiment can improve the overall production efficiency when it is difficult to improve the state transition probability 103 of a certain component state. Paths are generated and system design changes can be completed early. In addition, about the component similar to the said Embodiment 1-4, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the state transition definition changing unit 51 shown in FIG. 10, in order to increase the route information 105 output by the route extracting unit 12 when it is desired to change the value of the expected tact time after the evaluation once in the design stage, The definition unit 11 performs a design change in which part or all of the part states defined as being difficult to continue work are changed to a part state that can be connected to the target state. Thereby, the state transition information 501 in which the state transition probability 103 of the changed component state is updated is output and input to the route extraction unit 12. For example, in the case of a dice, let us consider a case where it is desired to complete the work with even-numbered eyes “2”, “4”, and “6” facing upward. Assume that it is assumed that the state transition is performed by executing the second operation only for those that have taken the even state “2”, “4”, and “6” in the state where the first operation is completed. In this case, it is conceivable to create a hand specialized for grasping “2”, “4”, and “6”. However, if the tact time does not increase, even if the odd number states are “1”, “3”, and “5” when the first work is completed, the hand design can be changed to allow the second work. , You can increase the overall tact time. Considering this as a state transition, this corresponds to creating a connectable transition by adding a measure such as modifying the system to a state transition that has been impossible to connect.

  With the above configuration, compared to the fourth embodiment, when making a design change at the examination stage, the improvement of the expected tact time reaches the target tact time 201 only by improving the design of the state transition probability 103 included in the existing route information 105. If the target cost is high or the target cost is high, the design can be presented to the designer as a whole to meet the target cost and the target tact time by increasing the number of target parts and increasing the number of paths. The effect that can be obtained.

Embodiment 6 FIG.
FIG. 11 is a diagram illustrating a functional configuration of the production performance evaluation apparatus for the mechanical system according to the sixth embodiment. In the sixth embodiment, in contrast to the first embodiment, the state transition probability 103 input to the state transition definition unit 11 is simulated by simulating the behavior of a part and using a simulation that may cause a failure. In addition, the embodiment further includes a configuration in which the state transition probability 103 can be obtained even if there is no operation record of the mechanical system. In addition, about the component similar to the said Embodiment 1-5, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the sixth embodiment, in addition to the configuration of the first embodiment, mechanical system operation simulation means 61 shown in FIG. 11 is provided. The mechanical system operation simulation means 61 uses the simulation reproducing the behavior of the robot, the mechanical system and the parts reproducing the relative dimensional relationship similar to the real space, and actually operates the robot and the mechanical system on the simulation to continue the work. Reproduce the impossible state. For example, when the contact phenomenon between objects is simulated, and the object cannot be gripped unless certain conditions are met, or the image processing using a vision sensor is simulated, and the shape, position, and orientation of the object cannot be recognized correctly In addition, the state of failing to grasp the object is reproduced. A feature of the sixth embodiment is that the state transition probability 103 is statistically obtained by performing repeated work using such mechanical system operation simulation means 61.

  With the above configuration, it is possible to define the state transition probability 103 without using past knowledge about the state transition probability 103 of the actual mechanical system and the actual operation result of the actual mechanical system, thereby reducing the prototype evaluation of the mechanical system. In addition, the design time can be shortened.

  FIG. 12 is a diagram illustrating a hardware configuration of a production performance evaluation apparatus for a mechanical system. The production performance evaluation apparatus 1 for a mechanical system exemplified in the first to sixth embodiments includes, for example, a CPU (Central Processing Unit) 1a and a memory 1b. In the machine system production performance evaluation apparatus 1, by executing a program, a CPU (Central Processing Unit) 1a causes a state transition definition means 11, a path extraction means 12, a path cycle time calculation means 13, an expected tact time calculation means 14, and a state. It functions as a transition change amount calculation unit 21, a device selection unit 31, a cost calculation unit 41, a state transition definition change unit 51, and a mechanical system operation simulation unit 61. A memory 1b such as a ROM (Read Only Memory) functions as the working time / state transition probability storage means 22. The program executed by the CPU 1a may be stored in the memory 1b or may be stored in another storage medium. When the device selection unit 31 also has a function of registering device information, the function part for registering information may be realized by the memory 1b.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  DESCRIPTION OF SYMBOLS 1 Machine system production performance evaluation apparatus, 2, 2a, 2b Robot, 2c Vision sensor, 3 Conveyor, 4 Control controller, 5 Information integration device, 6 Display apparatus, 11 State transition definition means, 12 Path extraction means, 13 Path cycle Time calculation means, 14 Expected tact time calculation means, 21 State transition change amount calculation means, 22 Work time / state transition probability storage means, 31 Device selection means, 41 Cost calculation means, 51 State transition definition change means, 61 Mechanical system operation Simulation means.

Claims (7)

A state transition defining means for defining a state transition probability and a working time between the component states with respect to a component state defined by positions or postures that the component can take before and after the work process of the mechanical system;
Path extraction means for extracting a transition path from an initial state to a target state based on the state transition probability and the work time;
A path cycle time calculating means for calculating a path cycle time, which is an expected value of the time taken for transition between the component states, with respect to the transition path, from the state transition probability and the work time;
Expected tact time calculating means for calculating an expected tact time that is a time required for one part to reach a target state in the mechanical system from the path cycle time and the transition path extracted by the path extracting means. An apparatus for evaluating production performance of a mechanical system. When the expected tact time is larger than a target tact time that is a target tact time, at least one change amount of the state transition probability and the work time is determined for at least one of the transition paths, A state transition change amount calculating means for changing at least one of the state transition probability and the work time by the change amount;
The machine system production performance evaluation apparatus according to claim 1, wherein the expected tact time calculation means calculates the expected tact time again based on the changed transition probability and the work time.   The machine state production performance evaluation apparatus according to claim 2, wherein the state transition change amount calculating means determines the change amount candidates for a plurality of the transition paths. When the expected tact time is larger than a target tact time that is a target tact time, the apparatus further includes a device selection unit that outputs device information indicating a replaceable device among devices included in the mechanical system,
The machine system performance evaluation apparatus according to claim 1, wherein the expected tact time calculation means calculates the expected tact time when the device is replaced.   The machine system production performance evaluation apparatus according to claim 1, further comprising cost calculation means for calculating a cost related to a device of the mechanical system. Mechanical system operation simulation means for simulating the behavior of the mechanical system and the component,
The machine state production performance evaluation apparatus according to claim 1, wherein the state transition defining unit defines the state transition probability based on a simulation result. Defining a state transition probability and a working time between the component states with respect to a component state defined by positions or postures that the component can take before and after the work process of the mechanical system;
Extracting a transition path from an initial state to a target state based on the state transition probability and the working time;
Calculating a path cycle time, which is an expected value of the time taken to transition between the component states, with respect to the path from the state transition probability and the work time;
A step of calculating an expected tact time, which is a time required for one component to reach a target state in the mechanical system, from the path cycle time and the transition path extracted by the path extraction unit. A production system performance evaluation method.

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