Oht adaptive robust constraint following control method, oht system and product

Abstract

The application discloses an OHT adaptive robust constraint following control method, an OHT system and a product, and relates to the fields of automatic material handling systems and motion control technologies.The OHT adaptive robust constraint following control method of the application constructs structural consistency constraints between mechanisms of an OHT system in an over-parameterized coordinate space in an explicit manner, compiles the structural consistency constraints and end trajectory servo constraints into unified constraints, further constructs a virtual generalized input comprising a nominal Udwadia-Kalaba constraint compensation term, a constraint error feedback term and a leakage type adaptive robust compensation term, and converts a 10-dimensional over-parameterized virtual generalized input into a 4-dimensional actual execution input through virtual work equivalent projection, so that the control result in the constraint space is applied to four motion channels of a trolley, a sliding table, a lifting device and a rotating device, and the trajectory tracking precision, the structural constraint maintaining capability and the anti-disturbance robustness of the OHT system are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of automated material handling systems and motion control technology, specifically to: 1. an adaptive robust constraint following control method for OHT (Overhead Hoist Transport); 2. an OHT system; 3. a computer program product. Background Technology

[0002] In semiconductor manufacturing workshops, OHT systems are responsible for the automated handling of wafer cassettes or carriers. Their positioning accuracy, docking reliability, and handling stability directly affect production cycle time and wafer safety.

[0003] See Figure 1 An OHT system typically includes a trolley mechanism that runs along a track, a slide mechanism for lateral adjustment relative to the trolley, a lifting mechanism for raising and lowering the load, and a rotary mechanism for fine-tuning the end angle. x (Displacement along the track direction) y (Lateral displacement of the slide mechanism) z (Longitudinal displacement of the lifting mechanism) 、 (The rotation angle of the rotary mechanism) has a total of 4 degrees of freedom. The end of the OHT system is usually equipped with an actuator (such as a gripper) driven by the rotary mechanism.

[0004] Existing control schemes often simplify the OHT control problem into a trajectory tracking problem with independent coordinates. Typical schemes include PID / PD control, input shaping, sliding mode control, model predictive control, and conventional adaptive control. These schemes can achieve basic position tracking or sway suppression under specific operating conditions. However, for OHT systems, controlling only the coordinate error is insufficient, and situations can easily arise where the coordinate tracking error is small, but the system motion does not meet structural compatibility requirements. Moreover, OHT systems are also affected by factors such as load mass variations, track friction variations, lift damping variations, installation deviations, track disturbances, sensor errors, and unmodeled dynamics. Existing control methods struggle to simultaneously guarantee trajectory tracking accuracy, constraint consistency, and disturbance rejection robustness. Summary of the Invention

[0005] Therefore, it is necessary to address the problem that existing control schemes for OHT systems often result in small coordinate tracking errors but the system motion does not meet structural compatibility requirements, making it difficult to simultaneously guarantee trajectory tracking accuracy, constraint consistency, and disturbance rejection robustness. This necessitates providing an OHT adaptive robust constraint following control method, OHT system, and related products.

[0006] This invention is achieved using the following technical solution: In a first aspect, the present invention discloses an OHT adaptive robust constraint following control method, which includes: Step 1: Obtain the desired trajectory of the OHT system in the current control cycle. q d Actual minimum coordinate vector q m and will q m Perform coordinate linear mapping to obtain the actual overparameterized coordinate vector. ; Step two, based on , q d For the OHT system, structural consistency constraints and end-point trajectory servo constraints are generated, and a unified constraint following form is used to extract the input control parameters for the current control cycle; the input control parameters include: a unified constraint matrix. A Unified constraint on the right-hand vector c Target constraint acceleration vector b Constrained following error β ; Step 3: Calculate the virtual generalized input based on the input control parameters of the current control cycle. t ;in, ; p 1 is the nominal Udwadia-Kalaba constraint compensation term; p 2 represents the constraint error feedback term. p 3 represents the leaky adaptive robust compensation term; Step four, use virtual work equivalent projection to... t Converted into the actual generalized input of the OHT system u ; Step 5, according to u The corresponding control is applied to the trolley mechanism, slide mechanism, lifting mechanism, and slewing mechanism, and then enters the next control cycle.

[0007] The implementation of this OHT adaptive robust constraint following control method is based on the method or process of embodiments of this disclosure.

[0008] Secondly, the present invention discloses an OHT system that employs the OHT adaptive robust constraint following control method disclosed in the first aspect.

[0009] The implementation of such an OHT system is based on the method or process of an embodiment of this disclosure.

[0010] Thirdly, the present invention discloses a computer program product, comprising a computer program. When executed by a processor, the computer program implements the steps of the OHT adaptive robust constraint following control method disclosed in the first aspect.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention explicitly constructs structural consistency constraints between various mechanisms of the OHT system in an overparameterized coordinate space, and integrates the structural consistency constraints and the end-point trajectory servo constraints into a unified constraint. This enables the OHT system to maintain the structural compatibility relationship between the trolley mechanism, slide mechanism, lifting mechanism, and rotary mechanism while following the desired end-point trajectory. Furthermore, it constructs a virtual generalized input consisting of a nominal Udwadia-Kalaba constraint compensation term, a constraint error feedback term, and a leakage-type adaptive robust compensation term. Through virtual work equivalent projection, the 10-dimensional overparameterized virtual generalized input is converted into a 4-dimensional actual execution input. Without adding additional actuators, the constraint space control results can be applied to the four motion channels of the trolley, slide, lifting, and rotary, effectively improving the trajectory tracking accuracy, structural constraint maintenance capability, and disturbance rejection robustness of the OHT system.

[0012] 2. The virtual generalized input of the present invention utilizes the nominal control action required to satisfy the unified constraint, uses the constraint error feedback term to suppress the system deviation from the unified constraint manifold, and uses the leakage-type adaptive robust compensation term to compensate for the bounded unknown uncertainties caused by load changes, friction changes, damping changes, track disturbances, installation errors, unmodeled dynamics and external disturbances, thus ensuring the accuracy of input control.

[0013] 3. The leakage-type adaptive robust compensation term of the present invention uses the forward Euler method to discretely update the adaptive parameter estimate, keeping it at a reasonable value and avoiding affecting the stability of control and engineering feasibility. Attached Figure Description

[0014] To more clearly illustrate the solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the OHT system. Figure 2 The flowchart is for the OHT adaptive robust constraint following control method provided in Embodiment 1 of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] Example 1 It should be noted that, as described in the background art, the OHT system includes at least: a trolley mechanism running along the track, a slide mechanism for lateral adjustment relative to the trolley, a lifting mechanism for raising and lowering the load, and a rotary mechanism for fine-tuning the end angle; the end of the OHT system is equipped with an actuator driven by the rotary mechanism.

[0020] This embodiment 1 provides an OHT adaptive robust constraint following control method, which aims to control the above-mentioned OHT system through multiple control cycles so that its end effector follows the desired trajectory.

[0021] like Figure 2 As shown, this OHT adaptive robust constraint following control method includes: Step 1: Obtain the desired trajectory of the OHT system in the current control cycle. q d Actual minimum coordinate vector q m and will q m Perform coordinate linear mapping to obtain the actual overparameterized coordinate vector. .

[0022] in, q d Includes: the desired displacement along the orbital direction xd Horizontal desired displacement y d Longitudinal expected displacement z d Expected rotation angle ;Right now .

[0023] q m The minimum generalized coordinate system corresponding to the OHT system represents the four actual execution degrees of freedom of the OHT system, which are four dimensions in total. q m It can be represented as: In the formula, x This indicates the displacement of the trolley mechanism along the track direction. y This indicates the lateral displacement of the slide mechanism. z Indicates the longitudinal position of the actuator reference point. This indicates the rotation angle of the rotary mechanism.

[0024] and The corresponding overparameterized coordinate system for the OHT system—characterizing the structural consistency relationships between the various mechanisms of the OHT system—has 10 dimensions. Therefore, It can be represented as: In the formula, x c Represents the coordinates of the reference point of the trolley mechanism along the track direction; x s , y s Indicates the coordinates of the reference point of the slide mechanism; x h , y h , z h Indicates the coordinates of the reference point for the lifting mechanism; x t , y t , z t This represents the coordinates of the actuator's reference point; where, z = z t , z h = z + d 40 , d 40 This indicates a fixed vertical geometric offset between the reference point of the lifting mechanism and the reference point of the actuator.

[0025] It is important to note that if the minimum generalized coordinate system and the overparameterized coordinate system satisfy a linear mapping relationship, then...q m , satisfy: ; In the formula, T Represents a constant matrix. c 0 indicates the same as d 40 The relevant constant vectors.

[0026] Furthermore, taking the first and second derivatives of the above equation, we have: ; ; In the formula, This represents the actual minimum velocity vector of the OHT system in the current control cycle; This represents the actual overparameterized velocity vector of the OHT system in the current control cycle; This represents the actual minimum acceleration vector of the OHT system in the current control cycle; This represents the actual overparameterized acceleration vector of the OHT system in the current control cycle.

[0027] After the above coordinate linear mapping, although the OHT system has only four independent degrees of freedom, it can explicitly express structural constraints in a high-dimensional coordinate space.

[0028] Step two, based on , q d For the OHT system, structural consistency constraints and end-point trajectory servo constraints are generated, and a unified constraint following form is used to extract the input control parameters (including: unified constraint matrix) for the current control cycle. A Unified constraint on the right-hand vector c Target constraint acceleration vector b Constrained following error β ).

[0029] Specifically, based on actual overparameterized coordinate vectors Structural consistency constraints are constructed based on the geometric relationship with the OHT system, and the structural consistency constraint matrix is ​​extracted. A s Based on the expected trajectory q d The operation of the OHT system requires the construction of end-point trajectory servo constraints and the extraction of the task selection matrix. A t Task constraint right-hand vector c t Then, the two constraints are merged, and a unified constraint matrix is ​​extracted. A Unified constraint on the right-hand vectorc Target constraint acceleration vector b Constrained following error β .

[0030] The specific process of step two is as follows: 201. Based on the geometric relationship of the OHT system, we know that: The trolley mechanism, slide mechanism, lifting mechanism, and actuator satisfy positional consistency in the track direction (i.e.: The horizontal direction also satisfies positional consistency (i.e.: ).

[0031] See above. z = z t , z h = z + d 40 That is: z t - z + d 40 =0. Therefore, the position-level structural consistency constraints can be compiled as follows: .

[0032] Differentiating the above position-level structural consistency constraints yields the velocity-level structural consistency constraints (by taking the first derivative of these six equations with respect to time, and following...). (The order of components is used to write the derivative equation in matrix form). ;in, A s It is a constant matrix. .

[0033] Furthermore, by differentiating the structural consistency constraints of the velocity stage, we obtain the structural consistency constraints of the acceleration stage: .

[0034] Therefore, structural consistency constraints include the aforementioned position-level structural consistency constraints, velocity-level structural consistency constraints, and acceleration-level structural consistency constraints.

[0035] 202. First, from The reference point coordinates of the actuator and the rotation angle of the rotary mechanism are selected to form the actuator tracking variable vector. And construct tracking error .

[0036] Then, a first-order servo constraint is introduced: This transforms trajectory tracking into a constrained following problem. In the formula, forq t The first derivative; The task convergence gain matrix is ​​either positive definite or diagonally positive definite.

[0037] Expanding the first-order servo constraints along the track direction, lateral direction, longitudinal direction, and rotation direction respectively, we obtain: ; In the formula, They represent x t , y t , z t , The first derivative; They represent x d , y d , z d , The first derivative; K x , K y , K z , These represent the trajectory error convergence gain along the track direction, lateral direction, longitudinal direction, and rotation direction, respectively; e x , e y , e z These represent the position tracking errors along the track direction, laterally, and longitudinally, respectively. This indicates the tracking error of the rotation angle.

[0038] because Therefore: Substituting the first-order servo constraints into the above, we obtain the end-point trajectory servo constraints: .

[0039] It should be noted that, A t c t This corresponds to a parametric coordinate system: ; .

[0040] 203. A s , A t Merge by row ;Will c tExpand to This leads to the first-order unified constraint: Then define the constraint following error. ;in, β When the value is 0, both the structural consistency constraint and the end-point trajectory servo constraint are satisfied.

[0041] Differentiating the above first-order unified constraint yields the unified constraint for the acceleration level: , b As the right-hand side of the unified constraint of the acceleration level, it is used to characterize the target acceleration that the system should satisfy under the current state and the desired trajectory.

[0042] b satisfy: ;in, express c The first derivative, express A The first derivative. Because... A Since it is a constant matrix, Therefore, .

[0043] Step 3: Calculate the virtual generalized input based on the input control parameters of the current control cycle. t .

[0044] t Even with a parametric coordinate system, it is still 10-dimensional. t It consists of three parts: the nominal Udwadia-Kalaba constraint compensation item. p 1. Constraint error feedback term p 2. Leakage-type adaptive robust compensation term p 3, that is: .

[0045] 301, for p For example, it is based on the OHT nominal dynamic model constructed in the overparameterized coordinate system, and is used to generate the virtual generalized force required to satisfy the unified constraints under the OHT nominal dynamic model conditions.

[0046] The expression for the OHT nominal kinetic model is as follows: ; In the formula, M 0 represents the nominal inertia matrix, which can generally be set as a constant diagonal matrix, i.e.: , diag(.) represents a diagonal matrix with the elements within the parentheses as the main diagonal elements and the rest as zero; m c Indicates the equivalent mass of the trolley mechanism; m sIndicates the equivalent mass of the slide mechanism; m h This indicates an improvement in the equivalent quality of the organization; m t This represents the equivalent mass of the actuator and the load it carries. It represents the equivalent moment of inertia of the rotary mechanism about its axis of rotation; The nominal non-inertial generalized term is represented, which includes the equivalent viscous damping and gravity terms for each channel; for simplicity, it will be... Abbreviated as f 0.

[0047] It should be noted that this method uses equivalent lumped mass and a constant diagonal inertia matrix to describe the main motion of the OHT system. Therefore, the nominal dynamic model of OHT does not explicitly retain the Coriolis / eccentric terms, and the unmodeled velocity-related coupling, frictional changes, and disturbances are all incorporated as bounded uncertainties into the subsequent adaptive robust compensation. That is, the bounded uncertainties can be expressed as: ;Δ M、 Δ f This represents the uncertainties caused by load changes, friction changes, damping changes, track disturbances, installation errors, flexibility effects, and external disturbances.

[0048] So, based on And the OHT nominal dynamic model, construct p 1: ; In the formula, the superscript "+" indicates the Moore-Penrose generalized inverse.

[0049] 302. Regarding p In point 2, it is to suppress the deviation of the actual system from the unified constraint manifold.

[0050] p The expression for 2 is: ; In the formula, k fb To constrain the error feedback gain, k fb >0; P m The constraint error weight matrix satisfies: .

[0051] p 2. Enhances the correction effect when the constraint error is large, and forms a dissipation term in the dynamics of the constraint error.

[0052] 403, for p 3, in particular, addresses the bounded but unknown uncertainties in actual OHT systems.

[0053] make For adaptive parameter estimates, If the vector is a non-negative basis function, then the uncertainty envelope is estimated. , t Indicates time.

[0054] See the definition above. Let the terminal velocity vector satisfy: .

[0055] because As a non-negative basis function vector that can be pre-selected based on system state and time, in this embodiment 1, only the vector with respect to the system state and time is selected. The relevant special cases are: ; In the formula, the first term Characterizing the squared-type uncertainty of velocity, the second term The third term, constant 1, characterizes linear velocity-type friction or damping uncertainty, while the constant 1 in the third term characterizes constant or slowly varying bias disturbances.

[0056] Let auxiliary variables And construct a continuous robust normalization function. ,in, e This represents the robustness threshold, used to avoid singularities and suppress excessive switching near constrained manifolds; e >0.

[0057] So, p The expression for 3 is: ; It is important to note that if If it's a conventional adaptive law, then under continuous disturbances or insufficient excitation, the estimated parameters may continuously increase, affecting control stability and engineering feasibility. Therefore, it is recommended to... Discrete updates are performed using the forward Euler method (i.e., using the parameter estimates of the current control cycle to calculate the parameter estimates of the next control cycle).

[0058] Specifically, The update formula is: ; In the formula, They represent the first k +1 control cycle and the first k The adaptive parameter estimate for each control cycle; Δ t Indicates the time interval between adjacent control cycles; Indicates the first k A vector of non-negative basis functions for each control cycle; Indicates the first kConstrained following error for each control cycle; k 1 is the adaptive gain and k 1 > 0 is used to make the parameter estimate increase as the constraint following error and uncertainty basis function increase; k 2 is the leakage coefficient and k 2 > 0 is used to suppress parameter drift caused by long-term disturbances or insufficient excitation.

[0059] That is, in the first k Within each control cycle, the system state and constraint following error are calculated... and will For the k Uncertainty envelope estimation and robust compensation calculation in +1 control cycle, thereby achieving cycle-by-cycle updating of parameter estimates, Keep it within a reasonable range.

[0060] Step four, use virtual work equivalent projection to... t Converted into the actual generalized input of the OHT system u ;in, , u x This represents the actual generalized driving force of the trolley mechanism along the track direction. u y This represents the actual generalized driving force in the lateral direction of the slide mechanism. u z This indicates an increase in the organization's actual, broad driving force in the vertical direction. This represents the actual driving torque of the rotary mechanism.

[0061] As can be seen from the aforementioned definition, t Located in a parametric coordinate space, it is 10-dimensional, but the OHT system actually only has 4 motion channels (i.e., 4 independent degrees of freedom), therefore it cannot be... t Instead of directly executing commands, they need to be projected into the four-dimensional actual execution space.

[0062] From the linear coordinate mapping relationship, we know that the allowable virtual displacement satisfies: ; According to the invariance of virtual work, we have: ; therefore, u It can be written as: .

[0063] In other words, the structural constraint line only generates virtual constraint forces within the constraint space, and does not require the OHT system to add additional actuators. The final control quantity is still applied to the four motion channels of the trolley, lateral movement, lifting and rotation.

[0064] Step 5, according to uThe corresponding control is applied to the trolley mechanism, slide mechanism, lifting mechanism, and slewing mechanism, and then enters the next control cycle.

[0065] In a real OHT system, the actual generalized input is... u In u x , u y , u z , The underlying servo drivers of each mechanism further convert these into corresponding motor torque, current, or speed control commands to be applied. Of course, as described above, after completing... u After applying control, it is recommended to update first. Then proceed to the next control cycle.

[0066] In summary, the OHT adaptive robust constraint following control method provided in Embodiment 1 explicitly constructs structural consistency constraints between various mechanisms of the OHT system in the overparameterized coordinate space, and integrates the structural consistency constraints and the end-point trajectory servo constraints into a unified constraint. This allows the OHT system to maintain the structural compatibility relationship between the trolley mechanism, slide mechanism, lifting mechanism, and slewing mechanism while following the desired end-point trajectory. Furthermore, it utilizes nominal Udwadia-Kalaba constraint compensation terms to generate nominal control actions that satisfy the unified constraints, uses constraint error feedback terms to suppress the system's deviation from the unified constraint manifold, and uses leakage-type adaptive robust compensation terms to compensate for bounded unknown uncertainties caused by load changes, friction changes, damping changes, track disturbances, installation errors, unmodeled dynamics, and external disturbances, thus forming a virtual generalized input. Then, through virtual work equivalent projection, the 10-dimensional overparameterized virtual generalized input is converted into a 4-dimensional actual execution input. Without adding additional actuators, the constraint space control results can be applied to the four motion channels of the trolley, slide, lifting, and slewing, effectively improving the trajectory tracking accuracy, structural constraint maintenance capability, and disturbance rejection robustness of the OHT system.

[0067] This embodiment 1 also discloses an OHT system, which adopts the above-mentioned OHT adaptive robust constraint following control method and can also achieve the same technical effect as the above method.

[0068] Example 2 To illustrate the effectiveness of the OHT adaptive robust constraint following control method provided in Example 1, this Example 2 performs motion simulation of the OHT system in the MATLAB environment.

[0069] First, adopt the complete The OHT system was controlled. Results show that, under fundamental uncertainties including time-varying mass, damping variations, and unmodeled residual dynamics, the actual trajectories of the four motion channels (trolley, slide, lifting, and rotation) quickly approach the desired trajectory after the initial transient, with the trajectory tracking error remaining near zero. The unified constraint following error norm decays rapidly and remains bounded, indicating that both structural consistency constraint residuals and end-point trajectory servo constraint residuals are effectively suppressed, and both types of constraints are well satisfied simultaneously. The adaptive parameter estimates change smoothly and remain bounded throughout the simulation, and the four actual generalized inputs also remain bounded, without any sustained high-frequency chattering.

[0070] Secondly, a virtual generalized input with leakage-type adaptive robust compensation terms is adopted. Control the OHT system and integrate it with the complete system. Ablation comparisons were performed. The comparison results showed that... Although it can achieve basic stability and constrained following, it suffers from significant residual tracking and constrained following errors under the influence of uncertainties; further... p After step 3, the residual errors of each channel and the norm of the unified constraint following error further decreased, while the overall amplitude of the actual generalized input remained at a similar level. This indicates that the performance improvement comes from the active compensation for unknown uncertainties and disturbance residuals, rather than simply increasing the control action.

[0071] Next, the method of Example 1 is compared with the PD control method with nominal gravity compensation: To quantitatively evaluate control performance, the following three performance indicators are used: 1. Longitudinal tracking error integral index (IAE) z 1. It is used to evaluate the longitudinal trajectory tracking accuracy; 2. Unified constraint following error integral index I β It is used to evaluate the cumulative deviation of uniform constraints; 3. Integrated control action index I u It is used to evaluate the overall control effect of the actuator.

[0072] 1. Under the same conditions of desired trajectory, initial conditions, controlled object model with uncertainties, and actual input definition, the two methods are compared. The results show that the method in Example 1 achieves smaller tracking errors in all four motion channels (cart, slide, lifting, and rotation) and significantly reduces the uniform constraint following error. Specifically, compared with the PD control method, the method in Example 1 has a lower IAE (Intra-Effective Field)... z Approximately 94.7% reduction, I β It decreased by approximately 95.3%, while I u The increase of only about 1.0% indicates that the method of Example 1 can achieve higher trajectory tracking accuracy and constraint retention capability with essentially the same actuator action.

[0073] 2. Different disturbance conditions were set (including only the condition with basic uncertainty, high-frequency disturbance condition, low-frequency disturbance condition, and strong low-frequency disturbance condition), and the two methods were compared. The results showed that the method in Example 1 could keep the longitudinal tracking error near zero and make the uniform constraint following error significantly smaller than that of the PD control method, indicating that it has good suppression capabilities for rapid oscillation disturbances, slow-changing continuous disturbances, and strong low-frequency disturbances.

[0074] As can be seen from the above simulation, the method in Example 1 can simultaneously achieve end-point trajectory tracking, structural consistency maintenance, adaptive parameter boundedness, and smooth output of actual execution input under the presence of uncertainty and external disturbances. This verifies that the combination of nominal constraint compensation, constraint error feedback, and leakage-type adaptive robust compensation can effectively improve the control accuracy and disturbance rejection robustness of the OHT system.

[0075] Example 3 This embodiment 3 discloses a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the OHT adaptive robust constraint following control method disclosed in embodiment 1.

[0076] The computer equipment can be a mobile terminal or a fixed terminal. Examples of mobile terminals include mobile phones, laptops, digital radio receivers, personal digital assistants (PDAs), tablet computers (PADs), portable multimedia players (PMPs), and in-vehicle terminals (such as in-vehicle navigation terminals); examples of fixed terminals include digital TVs and desktop computers.

[0077] This embodiment 3 also discloses a readable storage medium that stores computer program instructions. When the computer program instructions are read and executed by the processor, the steps of the OHT adaptive robust constraint following control method disclosed in embodiment 1 are performed.

[0078] The readable storage medium may include, but is not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the above.

[0079] This embodiment 3 also discloses a computer program product, including a computer program. When executed by a processor, this computer program implements the steps of the OHT adaptive robust constraint following control method disclosed in embodiment 1.

[0080] It should be noted that the computer program used to execute the above can be written in one or more programming languages ​​or a combination thereof. These programming languages ​​include object-oriented programming languages—such as Java, Smalltalk, and C++—as well as conventional procedural programming languages—such as C or similar languages. The computer program can be executed entirely on the user's computer, partially on the user's computer, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer through any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN).

[0081] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An OHT adaptive robust constraint following control method, characterized in that, It includes: Step 1: Obtain the desired trajectory of the OHT system in the current control cycle. q d Actual minimum coordinate vector q m and will q m Perform coordinate linear mapping to obtain the actual overparameterized coordinate vector. ; Step two, based on , q d For the OHT system, structural consistency constraints and end-point trajectory servo constraints are generated, and a unified constraint following form is used to extract the input control parameters for the current control cycle; the input control parameters include: a unified constraint matrix. A Unified constraint on the right-hand vector c Target constraint acceleration vector b Constrained following error β ; Step 3: Calculate the virtual generalized input based on the input control parameters of the current control cycle. τ ;in, ; p 1 is the nominal Udwadia-Kalaba constraint compensation term; p 2 represents the constraint error feedback term. p 3 represents the leaky adaptive robust compensation term; Step four, use virtual work equivalent projection to... τ Converted into the actual generalized input of the OHT system u ; Step 5, according to u The corresponding control is applied to the trolley mechanism, slide mechanism, lifting mechanism, and slewing mechanism, and then enters the next control cycle.

2. The OHT adaptive robust constraint following control method according to claim 1, characterized in that, The OHT system includes: a trolley mechanism that runs along the track, a slide mechanism that adjusts laterally relative to the trolley, a lifting mechanism for raising and lowering the load, and a rotary mechanism for fine-tuning the end angle; wherein, the end of the OHT system is equipped with an actuator driven by the rotary mechanism.

3. The OHT adaptive robust constraint following control method according to claim 2, characterized in that, In step one, , x d This represents the desired displacement along the orbital direction. y d This represents the expected lateral displacement. z d This represents the expected longitudinal displacement. Indicates the expected rotation angle; , x This indicates the displacement of the trolley mechanism along the track direction. y This indicates the lateral displacement of the slide mechanism. z Indicates the longitudinal position of the actuator reference point. Indicates the rotation angle of the rotary mechanism; , x c Represents the coordinates of the reference point of the trolley mechanism along the track direction; x s , y s Indicates the coordinates of the reference point of the slide mechanism; x h , y h , z h Indicates the coordinates of the reference point for the lifting mechanism; x t , y t , z t Indicates the coordinates of the actuator's reference point; , , ; T Represents a constant matrix. c 0 indicates AND d 40 The relevant constant vectors; d 40 This indicates a fixed vertical geometric offset between the lifting mechanism reference point and the actuator reference point; This represents the actual minimum velocity vector of the OHT system in the current control cycle; This represents the actual overparameterized velocity vector of the OHT system in the current control cycle; This represents the actual minimum acceleration vector of the OHT system in the current control cycle; This represents the actual overparameterized acceleration vector of the OHT system in the current control cycle.

4. The OHT adaptive robust constraint following control method according to claim 3, characterized in that, Step two includes: Based on actual overparameterized coordinate vectors Structural consistency constraints are constructed based on the geometric relationship with the OHT system, and the structural consistency constraint matrix is ​​extracted. A s Based on the expected trajectory q d The operation of the OHT system requires the construction of end-point trajectory servo constraints and the extraction of the task selection matrix. A t Task constraint right-hand vector c t Then, the two constraints are merged, and a unified constraint matrix is ​​extracted. A Unified constraint on the right-hand vector c Target constraint acceleration vector b Constrained following error β .

5. The OHT adaptive robust constraint following control method according to claim 4, characterized in that, Structural consistency constraints include: position-level structural consistency constraints, velocity-level structural consistency constraints, and acceleration-level structural consistency constraints; The expression for the location-level structural consistency constraint is: ; The expression for the velocity stage structural consistency constraint is: ; ; The expression for the structural consistency constraint of the acceleration stage is: ; Or / and, the expression for the end-point trajectory servo constraint is: ; ; ; They represent x d , y d , z d , The first derivative; K x , K y , K z , These represent the trajectory error convergence gain along the track direction, lateral direction, longitudinal direction, and rotation direction, respectively; e x , e y , e z These represent the position tracking errors along the track direction, laterally, and longitudinally, respectively. This indicates the tracking error of the rotation angle; or / and, , , , .

6. The OHT adaptive robust constraint following control method according to claim 1, characterized in that, In step three, p The expression for 1 is: ； In the formula, M 0 represents the nominal inertia matrix; f 0 represents a nominal non-inertial generalized term; p The expression for 2 is: ； In the formula, k fb To constrain the error feedback gain, k fb >0; P m This is the constraint error weight matrix; p The expression for 3 is: ； In the formula, m Indicates auxiliary variables; ; This represents the envelope of the estimated uncertainty; ; These are the adaptive parameter estimates. A vector of non-negative basis functions; ; γ ( m ) represents a continuous robust normalization function; ; ε This represents the robustness threshold.

7. The OHT adaptive robust constraint following control method according to claim 1 or 6, characterized in that, Discrete updates are performed using the forward Euler method, and the update formula is as follows: ； In the formula, They represent the first k +1 control cycle and the first k The adaptive parameter estimates for each control cycle; Δ t Indicates the time interval between adjacent control cycles; Indicates the first k A vector of non-negative basis functions for each control cycle; Indicates the first k Constrained following error for each control cycle; k 1 is the adaptive gain and k 1 > 0; k 2 is the leakage coefficient and k 2 > 0.

8. The OHT adaptive robust constraint following control method according to claim 5, characterized in that, In step four, ; T Represents a constant matrix; , u x This represents the actual generalized driving force of the trolley mechanism along the track direction. u y This represents the actual generalized driving force in the lateral direction of the slide mechanism. u z This indicates an increase in the organization's actual, broad driving force in the vertical direction. This represents the actual driving torque of the rotary mechanism.

9. An OHT system, characterized in that, It employs the OHT adaptive robust constraint following control method as described in any one of claims 1-8.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the OHT adaptive robust constraint following control method as described in any one of claims 1-8.

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