Self-adaptive production control unit based on hormone regulation mechanism

Abstract

According to the self-adaptive production control unit based on the hormone regulation and control mechanism, the overstock task variable quantity and the product-in-process fluctuation quantity are introduced into controller parameter design, correlation between controller parameters and workshop system performance indexes is achieved, and the robustness of a control system is improved. When the control unit is in a conventional state, compared with a traditional controller, the designed controller is better in system stability. The production capacity can be adjusted in time, overstocked tasks can be rapidly eliminated, and meanwhile in the whole production capacity adjusting process, the product stock can be kept within a reasonable fluctuation range. In a limit state, when a product stock reaches a certain limit value, the damping characteristic of a workshop manufacturing system is limited to a certain extent. The backlog task controller based on the hormone regulation and control mechanism can regulate and control the production process more stably, and the production process is prevented from being excessively fluctuated. The value of the key parameter-production advance period of the system is changed, the system sensitivity is low, and the system requirements under different working conditions can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial automation control, and in particular to an adaptive production controller suitable for discrete manufacturing workshops, which realizes dynamic production regulation by combining bionics principles with control theory. Background Art

[0002] The goals of production control vary in different manufacturing system environments. In the current environment, discrete manufacturing workshops generally arrange production according to customer orders. In actual operation, the system first needs to determine the order in which orders are released. The order is generally determined by the order in which the orders arrive, and then the production of products is specifically arranged based on the order in which the orders are released. For the entire system, it is necessary to make decisions on the optimization of order production sequencing based on the system's comprehensive performance indicators. At the same time, the workshop manufacturing system is driven by orders (confirmed orders and intended orders). The number of orders and their specific product requirements determine the production tasks within the system at different times. The large or small number of order tasks in certain periods may cause the company's production load rate to be high or even idle.

[0003] Therefore, during the design phase of the production controller, the following two aspects need to be considered: first, how to determine the order placement rate based on the production control target; second, what production capacity control strategy should be adopted to deal with disturbances - fluctuations in order tasks after the order is placed. Figure 1 The figure shows a cascade production controller model proposed from the perspective of control theory. The controller has four basic control loops: order generation, order release, order sequencing, and capacity control.

[0004] The basic idea of ​​the cascade control model is to nest multiple closed loops together and divide the controllers into master and slave controllers. The target value of the slave controller is determined by the set value of the master controller, and the master controller acts on the outer loop at a lower operating frequency. Figure 1 In the model shown, the order generation layer and the order release layer are merged into one layer to form the production planning layer; at the same time, order scheduling and capacity control are classified as the execution layer of the workshop or workstation, and the following is established: Figure 2 The production control system model shown is based on the backlog task controller and work-in-process controller.

[0005] This model integrates concepts from load control and constraint theory, employing control theory to establish a dual closed-loop control system with work-in-process (WIP) and backlog as core variables. The system's design philosophy is to first convert discrete orders into continuous ones at the planning level, using the order flow as the controller's input variable. The WIP controller then adjusts the order flow in real time to maintain WIP at an appropriate level, ensuring equipment utilization at the shop floor level. This ensures a fast, accurate, and stable order flow, thereby ensuring reliable delivery dates. Furthermore, during the actual operation of the shop floor manufacturing system, internal and external disturbances such as urgent orders and rework can cause the system's actual production capacity to deviate from the planned value, resulting in backlogs. To address this, the system must adjust the production capacity of key resources to stimulate order placement, thereby controlling WIP and achieving synchronized production. By controlling the order placement rate and production capacity to address external demand uncertainty, this approach provides a strategy for upper-level decision-making in shop floor manufacturing systems.

[0006] Others have designed proportional-control-based WIP controllers and backlog controllers by defining average WIP inventory and backlog tasks, respectively. Simulation results show that appropriately adjusting the controller proportional coefficient can effectively reduce the backlog. Regarding the parameter selection of the backlog controller, some have proposed using PID control to control the backlog task, but they have not addressed the optimization of PID parameters and have only presented simulation results based on proportional control. These studies all share a common shortcoming: the controller parameter settings are influenced by subjective factors and are not linked to the specific manufacturing process.

[0007] Discrete manufacturing plants are complex, large-scale systems, making accurate mathematical models nearly impossible to establish. Empirical design methods are often used to determine controller parameters, but these parameters are subject to subjective factors and are detached from actual on-site state feedback. Consequently, when the system's internal structure changes or external disturbances vary significantly, the control system's performance often declines significantly, or even becomes unstable, resulting in poor robustness of the system controller. Furthermore, plant manufacturing systems are frequently subject to internal and external disturbances. Conventional linear feedback control systems struggle to design appropriate production control strategies that ensure the plant system's performance reaches or approaches its desired values. Adaptive control, however, is an effective approach to addressing these challenges.

[0008] The hormone regulation mechanism in the neuroendocrine system has advantages such as good adaptability and stability, and has superior control performance compared to traditional PID controllers. Research on the biological control theory of the neuroendocrine system will provide new approaches to solving some complex problems. Summary of the Invention

[0009] The purpose of the present invention is to provide an adaptive production control unit based on a hormone regulation mechanism to solve the problems raised in the above background technology:

[0010] (1) How to dynamically adjust control parameters through bionic principles to solve the problems of poor robustness and slow response speed of traditional controllers and achieve workshop production balance under complex disturbances.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] An adaptive production control unit based on hormone regulation mechanism;

[0013] Includes backlog task controller, work-in-progress controller and system output threshold module;

[0014] The backlog controller acts as the main controller, eliminating backlogs by adjusting production capacity; the work-in-process controller acts as the auxiliary controller, stabilizing production by adjusting work-in-process levels and assisting the backlog controller in controlling the entire production process.

[0015] The control rules of the backlog task controller and the work-in-process controller are both based on the hormone regulation mechanism. Output threshold modules are introduced into the backlog task controller and the work-in-process controller to make them meet the actual regulation requirements and not exceed the physical conditions of the actual workshop manufacturing system.

[0016] The input and output parameters of the adaptive production control unit based on hormone regulation mechanism are described as follows:

[0017] In a workshop manufacturing system in equilibrium, the order quantity and order scheduling are equivalently simplified to the initial input rate of order release, which flows into the backlog task controller as the input source of the adaptive production control unit based on the hormone regulation mechanism;

[0018] The difference between the order rate and the actual production rate accumulated over a certain period of time is the backlog task, which serves as another input to the backlog task controller. Any changes in external demand will be directly reflected in the backlog task controller.

[0019] The product of the initial order input rate and the planned production lead time is the planned or ideal work-in-process inventory, and the difference between this and the actual work-in-process is used as the input to the work-in-process controller;

[0020] The output of the adaptive production control unit based on the hormone regulation mechanism takes the actual productivity and actual work-in-process inventory of the workshop manufacturing system as the main reference indicators.

[0021] On the basis of the above technical solution, the present invention can also be improved as follows.

[0022] Furthermore, when the shop floor manufacturing system is in equilibrium, its output rate is equal to the order input rate;

[0023] If the workshop manufacturing system cannot complete the production tasks on time due to random disturbance factors, resulting in a backlog of tasks, the backlog task controller can control or eliminate the backlog of tasks in the workshop manufacturing system by adjusting the production capacity of the workshop manufacturing system.

[0024] The backlog task is defined with an adjustment strategy based on planned capacity output, as follows:

[0025] B(t)=∫C a (t)dt-∫C p (t)dt (1)

[0026] Among them, Cp(t) represents the planned production capacity of the workshop manufacturing system, Ca(t) represents the actual production capacity of the workshop manufacturing system, and the production capacity and backlog tasks are compared to two hormones in the workshop manufacturing system. Considering the actual working conditions, the backlog task hormone is controlled by the production capacity hormone. If the backlog task is not equal to zero, it means that the workshop manufacturing system is affected by the disturbance factors and loses balance. At this time, the workshop manufacturing system is restored to balance by regulating the secretion of the production capacity hormone. The backlog task controller can be expressed as:

[0027] C a (t)=(αF up (B(t))+1)C p (t) (2)

[0028] Where:

[0029]

[0030] T bl =C f (t)(C f (t)-C p (t))

[0031] In the above formula, F up (B(t)) is the adaptive control function of the backlog task of the hormone regulation mechanism. The value of its control gain changes with the fluctuation of the backlog task B(t). Obviously, as B(t) increases, F up As the value of (B(t)) increases, the adjustment speed of the workshop manufacturing system becomes faster; a is the correction coefficient of the backlog task controller, where 0<α<1; C f (t) is the limit or rated production capacity of the workshop manufacturing system, and Tbl is the adjustment threshold of the backlog task controller.

[0032] Furthermore, as the deviation between the input rate and the output rate of the workshop manufacturing system accumulates over time, a work-in-progress inventory is formed, which causes a hysteresis effect in the workshop manufacturing system. The work-in-progress inventory of the workshop manufacturing system is:

[0033] WIP(t)=W in (t)-W o (t)+W d (t) (3)

[0034] In the above formula, W in (t) represents the input quantity of the workshop manufacturing system, W o (t) is the output of the workshop manufacturing system, W d (t) is the disturbance amount;

[0035] The main function of the work-in-process controller is to maintain the stability of the work-in-process by adjusting the order input rate during the production capacity adjustment process of the workshop manufacturing system, thereby maintaining the stability of the entire production process. The work-in-process inventory value is the ideal value WIP*. When the work-in-process inventory fluctuates due to disturbances or other factors, its deviation is:

[0036] eWIP(t)=WIP * (t)-WIP(t) (4)

[0037] Among them, WIP * (t) is the ideal work-in-process inventory, WIP(t) is the actual work-in-process inventory, and when the work-in-process inventory deviation is not zero, the control strategy of the work-in-process controller should satisfy:

[0038]

[0039] Where:

[0040]

[0041] T wip =WIP * (t)

[0042] Among them, I a (t) is the adjusted order entry rate, I a0 (t) is the initial order input rate; F up (eWIP(t)) and F down (eWIP(t)) is the WIP control function; β is the WIP controller adjustment factor and 0<β<1; T wip It is the threshold for work-in-process inventory control;

[0043] Order input rate and work-in-process inventory deviation are two hormones in the workshop manufacturing system, and their hormone secretion rate and hormone concentration are defined as I a(t) and eWIP(t), the order input rate is regulated by the secretion of the deviation hormone of the work-in-process inventory. When the workshop manufacturing system is affected by disturbance factors, the inherent balance of the workshop manufacturing system is broken and the order task volume is released to the workshop in advance; or when the production capacity is adjusted, the work-in-process inventory needs to be adjusted synchronously to improve equipment utilization;

[0044] When the work-in-process controller detects deviations in the work-in-process, it stimulates the secretion of order input rate hormones. Under the interaction of the two hormones, the work-in-process inventory level is stabilized again.

[0045] After adopting this structure, the hormone regulation mechanism of the biological neuroendocrine system is simulated, and a two-layer collaborative control architecture is designed. The backlog task controller (main controller), analogous to the growth hormone-releasing hormone (GHRH) regulation unit, dynamically adjusts the workshop production capacity to eliminate backlog tasks; the work-in-process controller (auxiliary controller), analogous to the somatostatin (SRIF) regulation unit, stabilizes the work-in-process inventory (WIP) by adjusting the order input rate; the output threshold module limits the adjustment range of production capacity to ensure compliance with the physical constraints of the workshop.

[0046] This adaptive production control unit based on the hormone regulation mechanism designs an adaptive production controller based on the hormone regulation control architecture, and designs the parameters of the adaptive production controller by drawing on the hormone regulation law. The backlog task change and work-in-process fluctuation are introduced into the controller parameter design, so that the controller parameters are associated with the performance indicators of the workshop manufacturing system, thereby improving the robustness of the control workshop manufacturing system.

[0047] The adaptive production control unit based on hormone regulation mechanism has the following advantages:

[0048] (1) Under normal conditions, the designed controller has better stability in the workshop manufacturing system than the traditional controller. It can adjust production capacity in a timely manner to quickly eliminate backlog tasks. At the same time, it can keep the product inventory within a reasonable fluctuation range during the entire production capacity adjustment process.

[0049] (2) Under the extreme state, when the work-in-process inventory reaches a certain limit, the damping characteristics of the workshop manufacturing system are limited to a certain extent. The backlog task controller based on the hormone regulation mechanism can regulate the production process more smoothly and avoid excessive fluctuations in the production process.

[0050] (3) Changing the value of the key parameter of the workshop manufacturing system - the production lead time. The workshop manufacturing system has low sensitivity and can adapt to the needs of the workshop manufacturing system under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a principle diagram of a cascade production control model based on cybernetics in the prior art.

[0052] Figure 2 The present invention is a schematic diagram of a backlog task controller of a closed-loop production control system in the prior art.

[0053] Figure 3 It is a schematic diagram of the growth hormone regulation model in the prior art.

[0054] Figure 4 This is a schematic diagram of the adaptive production control unit based on the hormone regulation mechanism in the embodiment of the adaptive production control unit based on the hormone regulation mechanism.

[0055] Figure 5 This is a schematic diagram of a backlog task controller in an embodiment of the adaptive production control unit based on the hormone regulation mechanism.

[0056] Figure 6 This is a schematic diagram of a product controller in an embodiment of the adaptive production control unit based on hormone regulation mechanism. DETAILED DESCRIPTION

[0057] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0058] The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only implementations.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0060] This adaptive production control unit based on hormone regulation mechanism transforms the traditional Figure 3 The growth hormone regulation model is combined with industrial production, and the GHRH neuroregulatory unit corresponds to the backlog task controller, and the SRI F neuroregulatory unit corresponds to the work-in-process controller (the work-in-process controller can also be called the work-in-process inventory controller). The actuator pituitary gland corresponds to the control object - the workshop manufacturing system, and the GH concentration in the body corresponds to the backlog task value and the work-in-process inventory. Figure 4The adaptive production control unit based on hormone regulation mechanism is shown.

[0061] Based on the coordination mechanism of the neuroendocrine system, the workshop system operates under a neuroregulatory mechanism under normal conditions. However, when the manufacturing system changes due to disturbances (such as the addition of urgent orders), the workshop system adaptively adjusts system parameters based on hormonal regulation to achieve rebalancing. When the workshop manufacturing system is disrupted by changes in external demand or the addition of urgent orders, its original balance is disrupted, and its system performance (system production capacity is insufficient) subsequently declines. The workshop manufacturing system uses hormonal-like regulation to adjust production capacity and order release rate in real time to keep backlogs and work-in-process inventory (WIP) within a normal fluctuation range.

[0062] Based on the aforementioned hormone regulation system, taking backlog and work-in-progress (WIP) as examples, we compare them to the two hormones of the shop floor manufacturing system, equating backlog deviation and WIP deviation to corresponding changes in hormone concentrations, and the order flow input rate and production capacity adjustment rate to the secretion rates of the affected hormones. Based on the aforementioned neuroendocrine hormone Hill function regulation principle, we construct an adaptive production control law for the shop floor manufacturing system. By monitoring the backlog and WIP of the shop floor manufacturing system, we can regulate the shop floor's production capacity and order input rate in real time, achieving rapid overall optimization and resource balancing of the shop floor manufacturing system under disturbances.

[0063] The meanings of the parameters in this adaptive production control unit based on hormone regulation mechanism are as follows:

[0064] T d : Production capacity adjustment delay time;

[0065] T lt : Actual production lead time;

[0066] PR: productivity;

[0067] T lt* : Planned production lead time;

[0068] WIP: actual work-in-process inventory level;

[0069] WIP*: Planned or desired work-in-process inventory level.

[0070] Figure 4 The adaptive controller shown here is designed to maintain stable production within the shop floor manufacturing system despite disturbances. By quickly and smoothly eliminating backlogs and maintaining work-in-process inventory at a reasonable level, the system exhibits a certain degree of "damping" characteristics.

[0071] Includes backlog task controller, work-in-progress controller and system output threshold module;

[0072] The backlog task controller and the work-in-process controller form a two-tier collaborative control architecture. The backlog task controller acts as the main controller, eliminating backlog tasks by adjusting production capacity; the work-in-process controller acts as the auxiliary controller, stabilizing production by adjusting the work-in-process level and assisting the backlog task controller in controlling the entire production process.

[0073] The control rules of the backlog task controller and the work-in-process controller are both based on the hormone regulation mechanism. Considering the physical limitations of actual workshop manufacturing systems during the regulation process (such as the inability to infinitely adjust production capacity and the limited number of work-in-process inventory locations), output threshold modules are introduced into the backlog task controller and the work-in-process controller to ensure that they meet actual regulation requirements and do not exceed the physical conditions of the actual workshop manufacturing system.

[0074] The input and output parameters of the adaptive production control unit based on hormone regulation mechanism are described as follows:

[0075] For a workshop manufacturing system in a balanced state, the order quantity and order scheduling are equivalently simplified to the initial input rate of order release, which then flows into the backlog task controller as one of the input sources of the adaptive production control unit based on the hormone regulation mechanism.

[0076] The difference between the order rate and the actual production rate accumulated over a certain period of time Td is the backlog task, which serves as another input to the backlog task controller. Therefore, any external demand changes (such as urgent orders, etc.) will be directly reflected in the backlog task controller.

[0077] The product of the initial order input rate and the planned production lead time (Tlt*) is the planned or ideal work-in-process inventory (WIP*), and the difference between it and the actual work-in-process (WIP) serves as the input to the work-in-process controller.

[0078] The output of the adaptive production control unit based on the hormone regulation mechanism takes the actual productivity (PR) and actual work-in-process inventory (WIP) of the workshop manufacturing system as the main reference indicators.

[0079] When the shop floor manufacturing system is in steady state (equilibrium), its output rate is equal to the order input rate;

[0080] When the input and output of the workshop manufacturing system do not match each other for a period of time, the work-in-progress inventory in the workshop manufacturing system will continue to fluctuate. For example, when the input rate of the workshop manufacturing system is greater than the actual production rate, the work-in-progress inventory will continue to increase. Conversely, the amount of work-in-progress inventory in the workshop manufacturing system will continue to decrease. When the workshop manufacturing system faces disturbances such as changes in demand, the workshop manufacturing system loses balance. As time accumulates and production capacity is insufficient, the backlog of tasks in the workshop manufacturing system will gradually increase.

[0081] According to the above analysis, this adaptive production control unit based on hormone regulation mechanism is designed in combination with control theory. Figure 5 The backlog task controller based on the hormone regulation mechanism shown in the figure is a simplified closed-loop control loop model. Normally, when the workshop manufacturing system is in equilibrium, it rationally allocates orders to match equipment loads and completes planned production tasks sequentially. However, if random disturbances, such as urgent orders or equipment failures, prevent the workshop manufacturing system from completing production tasks on schedule, resulting in a backlog, the backlog task controller can control or eliminate the backlog by adjusting the production capacity of the workshop manufacturing system.

[0082] In order to facilitate intuitive observation of the basic dynamic characteristics of the workshop manufacturing system and take into account the design of backlog task control, the backlog task is defined based on the adjustment strategy of planned capacity output. Its expression is as follows:

[0083] B(t)=∫C a (t)dt-∫C p (t)dt (1)

[0084] Among them, Cp(t) represents the planned production capacity of the workshop manufacturing system (ideally, when the workshop manufacturing system is in a balanced state, this value is equal to the customer demand), and Ca(t) represents the actual production capacity of the workshop manufacturing system. The production capacity and backlog tasks are compared to two hormones in the workshop manufacturing system. Considering the actual working conditions, the backlog task hormone is controlled by the production capacity hormone. If the backlog task is not equal to zero, it means that the workshop manufacturing system is affected by the disturbance factor (here, taking the emergency order as an example) and loses balance. At this time, the workshop manufacturing system is restored to balance by regulating the secretion of the production capacity hormone. Therefore, the backlog task controller can be expressed as:

[0085] C a (t)=(αF up (B(t))+1)C p (t) (2)

[0086] Where:

[0087]

[0088] T bl =C f (t)(C f (t)-C p (t))

[0089] In the above formula, F up (B(t)) is the adaptive control function of the backlog task of the hormone regulation mechanism. The value of its control gain changes with the fluctuation of the backlog task B(t). Obviously, as B(t) increases, F up As the value of (B(t)) increases, the adjustment speed of the workshop manufacturing system becomes faster. a is the correction coefficient of the backlog task controller, where 0<α<1; C f (t) is the limit or rated production capacity of the workshop manufacturing system, and Tbl is the adjustment threshold of the backlog task controller.

[0090] In actual operating conditions, adjustments to the production capacity of a workshop manufacturing system have a certain delay time; different adjustment ranges or adjustment methods result in different response delay times. The impact of the production capacity adjustment range and delay time on the dynamic characteristics of a workshop manufacturing system is well known. Furthermore, when adjusting production capacity, the duration of the adjusted production capacity must also be considered. For example, a large production capacity adjustment range may result in a short duration of operation, or a slow response time may result in a long duration of operation. A correction factor a is introduced in the controller parameter design to represent the weighting of these factors. Therefore, when a workshop manufacturing system is affected by factors such as urgent orders, it is necessary to consider multiple compromises when adjusting production capacity using a backlog task controller. This requires quickly eliminating backlog tasks to meet customer needs while ensuring a certain level of economic efficiency.

[0091] Work-in-process (WIP) is the accumulation of material flow over time. It characterizes the state of the shop floor manufacturing system and provides sufficient information flow for decision-making. Work-in-process inventory imbues the shop floor manufacturing system with a certain degree of inertia (or damping characteristics), providing data and information sources for dynamic analysis of the shop floor manufacturing system. The deviation between the input rate and output rate of the shop floor manufacturing system accumulates over time, forming work-in-process inventory and causing hysteresis in the shop floor manufacturing system. The above analysis shows that the work-in-process inventory of the shop floor manufacturing system is:

[0092] WIP(t)=W in (t)-W o (t)+W d (t) (3)

[0093] In the above formula, W in (t) represents the input quantity of the workshop manufacturing system, W o (t) is the output of the workshop manufacturing system, W d(t) is the disturbance amount, such as the disturbance amount caused by emergency orders.

[0094] like Figure 6 As shown in the figure, the main function of the designed work-in-process controller is to maintain the stability of the work-in-process by adjusting the order input rate during the production capacity adjustment process of the workshop manufacturing system, thereby maintaining the stability of the entire production process. Ideally, the work-in-process inventory value is the ideal value WIP*. When the work-in-process inventory fluctuates due to disturbances or other factors, its deviation is:

[0095] eWIP(t)=WIP * (t)-WIP(t) (4)

[0096] Among them, WIP * (t) is the ideal work-in-process inventory, and WIP(t) is the actual work-in-process inventory. When the work-in-process inventory deviation is not zero, the control strategy of the work-in-process controller should satisfy:

[0097]

[0098] Where:

[0099]

[0100] T wip =WIP * (t)

[0101] Among them, I a (t) is the adjusted order entry rate, I a0 (t) is the initial order input rate; F up (eWIP(t)) and F down (eWIP(t)) is the WIP control function; β is the WIP controller adjustment factor and 0<β<1; T wip This is the work in process inventory control threshold.

[0102] Similar to the design process of the backlog task controller mentioned above, the order input rate and work-in-process inventory deviation are regarded as two hormones in the workshop manufacturing system, and their hormone secretion rate and hormone concentration are defined as I a (t) and eWIP(t). The order input rate is regulated by the secretion of the hormone "Work in Process Inventory Deviation." When the workshop manufacturing system is affected by disturbances that disrupt its inherent balance, such as when the workshop manufacturing system is constrained by customer delivery deadlines and orders are released to the workshop in advance, or when production capacity is adjusted, the work in process inventory needs to be adjusted simultaneously to improve equipment utilization. When the work in process controller detects a deviation in the work in process (the secretion of the hormone "Work in Process Inventory"), it stimulates the secretion of the hormone "Order Input Rate." Through the interaction of these two hormones, the work in process inventory level is stabilized again.

[0103] The above is only one embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the principles of the present invention, and these should also be regarded as falling within the scope of protection of the present invention.

Claims

1. An adaptive production control unit based on hormone regulation mechanism, characterized by: Includes backlog task controller, work-in-progress controller and system output threshold module; The backlog controller acts as the main controller, eliminating backlogs by adjusting production capacity; the work-in-process controller acts as the auxiliary controller, stabilizing production by adjusting work-in-process levels and assisting the backlog controller in controlling the entire production process. The control rules of the backlog task controller and the work-in-process controller are both based on the hormone regulation mechanism. Output threshold modules are introduced into the backlog task controller and the work-in-process controller to make them meet the actual regulation requirements and not exceed the physical conditions of the actual workshop manufacturing system. The input and output parameters of the adaptive production control unit based on hormone regulation mechanism are described as follows: In a workshop manufacturing system in equilibrium, the order quantity and order scheduling are equivalently simplified to the initial input rate of order release, which flows into the backlog task controller as the input source of the adaptive production control unit based on the hormone regulation mechanism; The difference between the order rate and the actual production rate accumulated over a certain period of time is the backlog task, which serves as another input to the backlog task controller. Any changes in external demand will be directly reflected in the backlog task controller. The product of the initial order input rate and the planned production lead time is the planned or ideal work-in-process inventory, and the difference between this and the actual work-in-process is used as the input to the work-in-process controller; The output of this adaptive production control unit based on hormone regulation mechanism takes the actual productivity and actual work-in-process inventory of the workshop manufacturing system as the main reference indicators.

2. The adaptive production control unit based on hormone regulation mechanism according to claim 1 is characterized by: When the shop floor manufacturing system is in equilibrium, its output rate is equal to the order input rate; If the workshop manufacturing system cannot complete the production tasks on time due to random disturbance factors, resulting in a backlog of tasks, the backlog task controller can control or eliminate the backlog of tasks in the workshop manufacturing system by adjusting the production capacity of the workshop manufacturing system. The backlog task is defined with an adjustment strategy based on planned capacity output, as follows: B(t)=∫C a (t)dt-∫C p (t)dt (1) Among them, Cp(t) represents the planned production capacity of the workshop manufacturing system, Ca(t) represents the actual production capacity of the workshop manufacturing system, and the production capacity and backlog tasks are compared to two hormones in the workshop manufacturing system. Considering the actual working conditions, the backlog task hormone is controlled by the production capacity hormone. If the backlog task is not equal to zero, it means that the workshop manufacturing system is affected by the disturbance factors and loses balance. At this time, the workshop manufacturing system is restored to balance by regulating the secretion of the production capacity hormone. The backlog task controller can be expressed as: C a (t)=(αF up (B(t))+1)C p (t) (2) Where: T bl =C f (t)(C f (t)-C p (t)) In the above formula, F up (B(t)) is the adaptive control function of the backlog task of the hormone regulation mechanism. The value of its control gain changes with the fluctuation of the backlog task B(t). Obviously, as B(t) increases, F up As the value of (B(t)) increases, the adjustment speed of the workshop manufacturing system becomes faster; a is the correction coefficient of the backlog task controller, where 0<α<1; C f (t) is the limit or rated production capacity of the workshop manufacturing system, and Tbl is the adjustment threshold of the backlog task controller.

3. The adaptive production control unit based on hormone regulation mechanism according to claim 1 is characterized by: The deviation between the input rate and output rate of the workshop manufacturing system accumulates over time, forming a work-in-progress inventory, which causes a hysteresis effect in the workshop manufacturing system. The work-in-progress inventory of the workshop manufacturing system is: WIP(t)=W in (t)-W o (t)+W d (t) (3) In the above formula, W in (t) represents the input quantity of the workshop manufacturing system, W o (t) is the output of the workshop manufacturing system, W d (t) is the disturbance amount; The main function of the work-in-process controller is to maintain the stability of the work-in-process by adjusting the order input rate during the production capacity adjustment process of the workshop manufacturing system, thereby maintaining the stability of the entire production process. The work-in-process inventory value is the ideal value WIP*. When the work-in-process inventory fluctuates due to disturbances or other factors, its deviation is: eWIP(t)=WIP * (t)-WIP(t) (4) Among them, WIP * (t) is the ideal work-in-process inventory, WIP(t) is the actual work-in-process inventory, and when the work-in-process inventory deviation is not zero, the control strategy of the work-in-process controller should satisfy: Where: T wip =WIP * (t) Among them, I a (t) is the adjusted order entry rate, I a0 (t) is the initial order input rate; F up (eWIP(t)) and F down (eWIP(t)) is the WIP control function; β is the WIP controller adjustment factor and 0<β<1; T wip It is the threshold for work-in-process inventory control; Order input rate and work-in-process inventory deviation are two hormones in the workshop manufacturing system, and their hormone secretion rate and hormone concentration are defined as I a (t) and eWIP(t), the order input rate is regulated by the secretion of the deviation hormone of the work-in-process inventory. When the workshop manufacturing system is affected by disturbance factors, the inherent balance of the workshop manufacturing system is broken and the order task volume is released to the workshop in advance; or when the production capacity is adjusted, the work-in-process inventory needs to be adjusted synchronously to improve equipment utilization; When the work-in-process controller detects deviations in the work-in-process, it stimulates the secretion of order input rate hormones. Under the interaction of the two hormones, the work-in-process inventory level is stabilized again.

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