Intelligent nozzle deflection control method based on vector control

Abstract

The invention discloses an intelligent nozzle deflection control method based on vector control, and relates to the field of nozzle positioning control, and the method comprises the following steps: constructing a basic vector of nozzle deflection by using space vector voltage synthesis and coordinate transformation; based on the basic vector of nozzle deflection, generating a control instruction by using an improved self-adaptive predictive compensation and multi-level control strategy; and outputting a driving signal of the servo motor by utilizing a space vector pulse width modulation technology according to the control instruction. Space vector voltage synthesis, coordinate transformation, self-adaptive predictive compensation and a multi-level control strategy are innovatively combined, the limitation of traditional PID control in a nonlinear system is effectively overcome, the implementation difficulty of a complex intelligent control algorithm is avoided, the dynamic characteristics of the nozzle are fully considered, and the control precision of the nozzle is improved. Accurate control can be achieved in high-speed movement, and the control precision and the response speed of the spray head are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nozzle control, and in particular to a nozzle deflection intelligent control method based on vector control. Background Art

[0002] With the rapid development of industrial automation and intelligent manufacturing, high-precision and high-efficiency inkjet technology plays an increasingly important role in product identification, packaging printing and other fields. As an indispensable component of industrial production, the performance of the inkjet system directly affects product quality and production efficiency. In many inkjet systems, nozzle control is the key link to achieve precise positioning and high-quality printing. Traditional nozzle control mainly relies on mechanical structure and simple motor control, which is difficult to meet the requirements of modern industrial production for high precision, high speed and flexibility; therefore, the development of advanced nozzle control technology has become an important research direction in the field of automation control, attracting the attention of many researchers.

[0003] At present, the nozzle control technology has made some progress. Common control methods include PID control, fuzzy control and neural network control, which can achieve precise positioning of the nozzle by adjusting the speed and direction of the motor. Among them, PID control is widely used because of its simple and easy implementation characteristics. It optimizes the system response by adjusting the proportional, integral and differential parameters; fuzzy control and neural network control introduce intelligent algorithms, which can better handle nonlinear and time-varying characteristics; in addition, some researchers have also proposed a closed-loop control method based on visual feedback, which can accurately adjust the nozzle position by capturing the nozzle position in real time. The application of these technologies has greatly improved the performance of the inkjet system and made the nozzle control more accurate and stable.

[0004] However, the existing nozzle control technology still has some limitations. First, although the traditional PID control is simple and easy to use, its control effect is often unsatisfactory when facing complex nonlinear systems, and it is difficult to meet high-precision requirements; secondly, although the intelligent control algorithm has strong adaptability, its complex structure and cumbersome parameter adjustment process increase the difficulty of system implementation and the computational burden; thirdly, although the method based on visual feedback can improve the control accuracy, it is highly dependent on ambient light and image processing algorithms, and may be limited in certain application scenarios; in addition, the existing technology generally lacks sufficient consideration of the dynamic characteristics of the nozzle, and it is difficult to achieve precise control in high-speed motion. Therefore, the development of a new nozzle control method that can take into account control accuracy, response speed and ease of implementation is still an important topic of current research.

[0005] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0006] In response to the problems in the related technology, the present invention proposes an intelligent control method for nozzle deflection based on vector control, which has the advantages of innovatively combining space vector voltage synthesis, coordinate transformation, adaptive prediction compensation and multi-level control strategy, avoiding the difficulty of implementing complex intelligent control algorithms, achieving precise control in high-speed motion, and improving the accuracy and response speed of nozzle control, thereby solving the problems in the prior art that when faced with complex nonlinear systems, the control effect is often unsatisfactory, it is difficult to meet high-precision requirements, there is a general lack of sufficient consideration of the dynamic characteristics of the nozzle, and it is difficult to achieve precise control in high-speed motion.

[0007] To this end, the specific technical solution adopted by the present invention is as follows:

[0008] A method for intelligently controlling nozzle deflection based on vector control, the method comprising the following steps:

[0009] S1. Use space vector voltage synthesis and coordinate transformation to construct the basic vector for nozzle deflection;

[0010] S2, based on the basic vector of nozzle deflection, using improved adaptive prediction compensation and multi-level control strategy, generate control instructions;

[0011] S3, according to the control instruction, using the space vector pulse width modulation technology, output the driving signal of the servo motor;

[0012] Using space vector voltage synthesis and coordinate transformation, constructing the basic vector for nozzle deflection includes the following steps:

[0013] S11, based on the nozzle position information, using the improved double-link inverse kinematics equation, obtaining the target deflection angle of the nozzle;

[0014] S12, based on the target deflection angle, using the nozzle deflection control equation to obtain the control vector required for the nozzle deflection;

[0015] S13. Based on the control vector, the basic vector for nozzle deflection is generated by utilizing the space vector voltage synthesis principle.

[0016] Furthermore, based on the nozzle position information, using the improved double-link inverse kinematics equation, obtaining the target deflection angle of the nozzle includes the following steps:

[0017] S111, using a sensor to obtain nozzle position information, where the nozzle position information includes the current position, current speed, and current angular velocity of the current nozzle;

[0018] S112, predicting the position of the nozzle at the next moment based on the nozzle position information;

[0019] S113, calculating the target deflection angle of the nozzle according to the prediction result of the nozzle position at the next moment.

[0020] Further, according to the prediction result of the nozzle position at the next moment, calculating the target deflection angle of the nozzle includes the following steps:

[0021] S1131. Calculate the original deflection angle of the nozzle based on the improved double-link inverse kinematics equation;

[0022] The expression for calculating the original deflection angle of the nozzle is:

[0023]

[0024] θ2=arccos((R 2 +L1 2 -L2 2 ) / (2L1×R));

[0025]

[0026] In the formula, and Respectively represent the position coordinates of the nozzle in the horizontal and vertical directions at the next moment; R represents the distance from the nozzle to the origin; θ1 represents the original angle of the nozzle; θ2 represents the connecting rod angle; L1 represents the length of the first virtual connecting rod; L2 represents the length of the second virtual connecting rod; Indicates the original deflection angle of the sprinkler head;

[0027] S1132, generating a dynamic compensation item based on the current speed of the nozzle;

[0028] S1133. Calculate the target deflection angle according to the original deflection angle of the nozzle and the dynamic compensation item.

[0029] Further, based on the target deflection angle, using the nozzle deflection control equation, obtaining the control vector required for nozzle deflection includes the following steps:

[0030] S121. Establish a nozzle deflection control equation according to the target deflection angle, and calculate the control force required for nozzle deflection;

[0031] S122, based on the control force required for the nozzle deflection, using trigonometric function decomposition to obtain the horizontal component and the vertical component of the control force;

[0032] S123. Generate a control vector according to the horizontal component and the vertical component of the control force using the polar coordinate conversion formula.

[0033] Furthermore, based on the control vector and utilizing the space vector voltage synthesis principle, generating the basic vector for nozzle deflection includes the following steps:

[0034] S131. According to the principle of space vector voltage synthesis, define the basic vector of space vector voltage;

[0035] S132, using coordinate transformation, decomposing the control vector to obtain magnetic flux components and torque components;

[0036] S133, calculating the action time of two adjacent basic vectors based on the decomposed components;

[0037] S134. Generate a basic vector sequence for nozzle deflection according to the calculated action time.

[0038] Furthermore, based on the basic vector of the nozzle deflection, the control instructions are generated by utilizing the improved adaptive prediction compensation and multi-level control strategy, including the following steps:

[0039] S21, establishing a nozzle motion prediction equation based on the basic vector of nozzle deflection;

[0040] S22, updating the control parameters using an adaptive prediction compensation algorithm according to the nozzle motion prediction result;

[0041] S23. Based on the updated control parameters, a multi-level control strategy is used to generate a control instruction for the nozzle deflection. The control instruction for the nozzle deflection includes an orthogonal axis voltage instruction and a direct axis voltage instruction.

[0042] Furthermore, based on the basic vector of the nozzle deflection, establishing the nozzle motion prediction equation includes the following steps:

[0043] S211, calculating an equivalent voltage vector according to a basic vector for nozzle deflection control;

[0044] S212, calculating the motor torque based on the equivalent voltage vector;

[0045] S213. Based on the motor torque and the torque balance equation, a nozzle motion prediction equation is established.

[0046] Further, according to the nozzle motion prediction result, using the adaptive prediction compensation algorithm, updating the control parameters includes the following steps:

[0047] S221, calculating the predicted value of the nozzle position based on the nozzle motion prediction equation;

[0048] S222, calculating the prediction error according to the nozzle position prediction value;

[0049] S223. Based on the prediction error, the control parameters are optimized using an adaptive algorithm.

[0050] Further, based on the updated control parameters, using a multi-level control strategy, generating a control instruction for nozzle deflection includes the following steps:

[0051] S231, generating a desired orthogonal axis current using a position control layer strategy according to the updated control parameters;

[0052] S232, generating an orthogonal axis voltage command based on the desired orthogonal axis current using a torque control layer strategy;

[0053] S233. Generate a direct shaft voltage command based on the direct shaft current and using the flux control layer strategy.

[0054] Further, according to the control instruction, using the space vector pulse width modulation technology, outputting the driving signal of the servo motor includes the following steps:

[0055] S31, based on the control instruction, using coordinate transformation to obtain the voltage component in the stationary coordinate system;

[0056] S32, calculating the action time of the switch state according to the voltage component in the stationary coordinate system using the principle of space vector pulse width modulation;

[0057] S33. Based on the action time of the switch state, a modulation algorithm is used to output a driving signal of the servo motor.

[0058] The beneficial effects of the present invention are:

[0059] (1) The present invention effectively overcomes the limitations of traditional PID control in nonlinear systems by innovatively combining space vector voltage synthesis, coordinate transformation, adaptive prediction compensation and multi-level control strategy, avoids the difficulty of implementing complex intelligent control algorithms, and gets rid of the dependence of visual feedback methods on the environment; it not only improves the accuracy and response speed of nozzle control, but also simplifies the system implementation process and reduces maintenance costs. By fully considering the dynamic characteristics of the nozzle, the present invention can achieve precise control in high-speed motion, meet the strict requirements of modern high-speed inkjet printing systems, and provide a new and efficient solution for nozzle control technology, showing obvious advantages in control performance, system implementation and application adaptability.

[0060] (2) The present invention can more accurately predict and control the position of the nozzle by introducing improved double-link inverse kinematics equations and dynamic compensation terms, effectively improving the control accuracy. It not only takes into account the static position of the nozzle, but also takes into account dynamic factors such as speed and acceleration, so that the control system can better cope with nonlinear changes in high-speed motion. Secondly, the basic vector is generated by adopting the principle of space vector voltage synthesis, and combined with coordinate transformation technology, precise control of nozzle deflection is achieved. This method overcomes the limitations of traditional PID control in dealing with complex nonlinear systems and can maintain high-precision control under various working conditions. In addition, by introducing an adaptive prediction compensation algorithm, the control parameters can be dynamically adjusted according to the actual operating conditions, further improving the accuracy and robustness of the control. The application of multi-level control strategies, including position control, torque control and flux control, can comprehensively and accurately control the movement of the nozzle, which not only improves the control accuracy, but also optimizes the operating efficiency of the motor. The comprehensive application of these technologies enables the present invention to always maintain high-precision nozzle control in a high-speed and complex working environment, significantly improving the overall performance.

[0061] (3) The present invention avoids the cumbersome parameter adjustment process in the traditional intelligent control algorithm by rationally designing the control structure, greatly simplifies the difficulty of system implementation and reduces the development cost; secondly, the introduction of the adaptive prediction compensation algorithm can automatically adapt to different working conditions without frequent manual intervention, thereby enhancing the adaptability and stability of the system. This feature enables the present invention to be widely used in different types of inkjet printing equipment and has good versatility; furthermore, the present invention does not rely on a complex visual feedback system and gets rid of the dependence on ambient light and image processing algorithms, so that the nozzle can maintain stable performance in various application scenarios; in addition, by adopting the space vector pulse width modulation technology, it can quickly generate accurate driving signals, improve the real-time control, and meet the needs of high-speed printing; finally, the present invention fully considers the dynamic characteristics of the nozzle, and realizes the precise control of the nozzle in high-speed motion by establishing an accurate motion prediction equation. This method of comprehensively considering the dynamic characteristics of the system improves the control accuracy, stability and reliability, and makes the technical solution more adaptable and has a wider application prospect in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0063] Figure 1It is a flow chart of a method for intelligent control of nozzle deflection based on vector control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0065] According to an embodiment of the present invention, a method for intelligent control of nozzle deflection based on vector control is provided.

[0066] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to one embodiment of the present invention, a method for intelligent control of nozzle deflection based on vector control is provided, and the method for intelligent control of nozzle deflection based on vector control comprises the following steps:

[0067] S1. Use space vector voltage synthesis and coordinate transformation to construct the basic vector for nozzle deflection;

[0068] S2, based on the basic vector of nozzle deflection, using improved adaptive prediction compensation and multi-level control strategy, generate control instructions;

[0069] S3, according to the control instruction, using the space vector pulse width modulation technology, output the driving signal of the servo motor;

[0070] Using space vector voltage synthesis and coordinate transformation, constructing the basic vector for nozzle deflection includes the following steps:

[0071] S11, based on the nozzle position information, using the improved double-link inverse kinematics equation, obtaining the target deflection angle of the nozzle;

[0072] S12, based on the target deflection angle, using the nozzle deflection control equation to obtain the control vector required for the nozzle deflection;

[0073] S13. Based on the control vector, the basic vector for nozzle deflection is generated by utilizing the space vector voltage synthesis principle.

[0074] In one embodiment, based on the nozzle position information, using the improved double-link inverse kinematics equation, obtaining the target deflection angle of the nozzle includes the following steps:

[0075] S111, using a sensor to obtain nozzle position information, where the nozzle position information includes a current position, a current speed, and a current angular speed of the nozzle;

[0076] Specifically, based on the feedback data of the nozzle position collected by the sensor, the current position (x, y) and current speed (v x ,v y ) and current angular velocity w;

[0077] S112, predicting the position of the nozzle at the next moment based on the nozzle position information;

[0078] Specifically, based on the basic principles of kinematics, the concepts of uniform linear motion and uniform angular circular motion are combined. First, it is assumed that the nozzle performs uniform linear motion, and then the trajectory deviation caused by the angular velocity is superimposed. This superposition can approximate the actual motion well in a short time and can provide better predictions when computing resources are limited.

[0079] Specifically, the nozzle position information obtained in step S111 is used to predict the position of the nozzle at the next moment. The expression is:

[0080]

[0081] Wherein, Ts is the preset sampling period, which is 0.01 seconds in this embodiment; the predicted position coordinates of the nozzle at the next moment are As output, it is used to calculate the target deflection angle next.

[0082] S113, calculating the target deflection angle of the nozzle according to the prediction result of the nozzle position at the next moment.

[0083] In one embodiment, according to the prediction result of the nozzle position at the next moment, calculating the target deflection angle of the nozzle includes the following steps:

[0084] S1131. Calculate the original deflection angle of the nozzle based on the improved double-link inverse kinematics equation;

[0085] It should be noted that the two-link inverse kinematics equation is a basic concept in robotics and motion control. It is used to describe a system consisting of two connected rigid rods, where the first link (length L1) is fixed at the origin, the second link (length L2) is connected to the end of the first link, and the end effector of the system (in this case, the nozzle) is located at the end of the second link; the inverse kinematics problem is to solve the process of solving the angle that the two links should rotate so that the end effector reaches the target position (x, y) of the end effector when the target position (x, y) of the end effector is known.

[0086] In the present application, the double-link inverse kinematics equation is used as a mathematical model to describe and control the movement of the nozzle, thereby providing a simple and effective method to describe the movement of the nozzle in a two-dimensional plane, which can well capture the nonlinear relationship between the nozzle position and the control parameters. Compared with more complex models, the calculation of the double-link model is relatively simple and fast, and is suitable for real-time control; in addition, by adjusting the length of the virtual link (L1 and L2), it can adapt to different nozzle systems and working ranges; in the present application, the traditional double-link inverse kinematics equation is improved, and a speed compensation term is added to better adapt to the needs of high-speed inkjet printing. This improvement enables the model to take into account the dynamic characteristics of the nozzle and improves the control accuracy and response speed.

[0087] Specifically, a) first, measure the actual position of the nozzle at different deflection angles; b) then, use an optimization algorithm (the least square method is used in this embodiment) to fit these data points to obtain the best L1 and L2 values; c) finally, verify and fine-tune these parameters through actual testing. In this embodiment, through the above steps, it is finally determined that the lengths of the two virtual connecting rods suitable for this nozzle are L1 = 100 mm; L2 = 80 mm.

[0088] Specifically, according to step S112, the position coordinates of the nozzle at the next moment are obtained. Calculate the distance R from the nozzle to the origin, the expression is:

[0089]

[0090] Then calculate the original angle of the nozzle, the expression is:

[0091]

[0092] Then, using the virtual connecting rod length (L1, L2), the connecting rod angle θ2 is calculated, and the expression is:

[0093] θ2=arccos((R 2 +L1 2 -L2 2 ) / (2L1×R));

[0094] Finally, calculate the original deflection angle of the nozzle

[0095] In the formula, and They represent the horizontal and vertical position coordinates of the nozzle at the next moment respectively; R represents the distance from the nozzle to the origin; θ1 represents the original angle of the nozzle; θ2 represents the connecting rod angle; L1 represents the length of the first virtual connecting rod; L2 represents the length of the second virtual connecting rod; Indicates the original deflection angle of the sprinkler head.

[0096] S1132, generating a dynamic compensation item based on the current speed of the nozzle;

[0097] Specifically, based on the current nozzle speed (v x ,v y ) and speed compensation coefficient α, calculate the dynamic compensation term, the expression is

[0098] Specifically, a) test at different speeds and record the deviation between the actual position of the nozzle and the target position; b) if the deviation increases at high speed, appropriately increase the α value; if over-compensation occurs, reduce the α value; c) repeat the test until the minimum average deviation is obtained in the entire speed range. In the above embodiment, after multiple experiments and optimizations, the speed compensation coefficient α is finally determined to be 0.002rad·s2 / mm2.

[0099] S1133. Calculate the target deflection angle according to the original deflection angle of the nozzle and the dynamic compensation item.

[0100] Specifically, based on the basic deflection angle calculated in step S1131 and the dynamic compensation term generated in step S1132 Calculate the final target deflection angle The expression is

[0101] In one embodiment, based on the target deflection angle, using the nozzle deflection control equation, obtaining the control vector required for nozzle deflection includes the following steps:

[0102] S121. Establish a nozzle deflection control equation according to the target deflection angle, and calculate the control force required for nozzle deflection;

[0103] Specifically, based on the target deflection angle The nozzle deflection control equation is established to calculate the control force F required for nozzle deflection. The expression is:

[0104]

[0105] In the formula, is the PID control parameter; It is the current nozzle deflection angle.

[0106] S122, based on the control force required for the nozzle deflection, using trigonometric function decomposition to obtain the horizontal component and the vertical component of the control force;

[0107] Specifically, based on the control force F calculated in step S121, the horizontal component F of the control force is obtained by using the trigonometric function decomposition principle. xand the vertical component F y , the expression is

[0108] S123. Generate a control vector according to the horizontal component and the vertical component of the control force using the polar coordinate conversion formula.

[0109] Specifically, according to the control force horizontal component F obtained in step S122 x and the vertical component F y , using the polar coordinate conversion formula, generate the control vector in polar coordinate form (|F|,θ F ), the expression is:

[0110]

[0111] θ F =arctan(F y ,F x );

[0112] Where |F| is the modulus of the control vector, which indicates the magnitude of the control force required for nozzle deflection; θ F It is the argument of the control vector, indicating the direction of the control force required for nozzle deflection.

[0113] In one embodiment, based on the control vector and using the space vector voltage synthesis principle, generating the basic vector for nozzle deflection includes the following steps:

[0114] S131. According to the principle of space vector voltage synthesis, define the basic vector of space vector voltage;

[0115] Specifically, in order to achieve precise deflection control of the nozzle, six basic control vectors V1 (100), V2 (110), V3 (010), V4 (011), V5 (001), and V6 (101) are defined; these vectors represent different combination states of the two servo motors that drive the nozzle deflection, and the three-digit number in the brackets represents the state of the two servo motors and an auxiliary control signal. These six basic control vectors constitute six key points in the nozzle deflection control space and are used to synthesize any required nozzle deflection control instructions.

[0116] Specifically, the first two digits of the three-digit number correspond to the two servo motors that control the horizontal and vertical deflection of the nozzle; the third digit represents an auxiliary control signal for fine-tuning or balance control; the number "1" indicates that the corresponding control unit is in a forward drive state, and the number "0" indicates that the corresponding control unit is in a reverse drive or stationary state.

[0117] For example, in the above embodiment, V1 (100) indicates that the horizontal deflection motor is driven in the forward direction, and the vertical deflection motor and the auxiliary control are stationary; V2 (110) indicates that the horizontal and vertical deflection motors are driven in the forward direction at the same time, and the auxiliary control is stationary; V3 (010) indicates that only the vertical deflection motor is driven in the forward direction, and the horizontal deflection motor and the auxiliary control are stationary. These six basic control vectors represent the key control states of the nozzle deflection system. By reasonably combining these basic vectors, any desired deflection control instructions can be synthesized in the control space, thereby realizing precise control of the nozzle position.

[0118] S132, using coordinate transformation, decomposing the control vector to obtain magnetic flux components and torque components;

[0119] It should be noted that the α-β coordinate system (stationary coordinate system) is a stationary two-phase coordinate system commonly used in motor control, also known as the Clarke coordinate system.

[0120] Specifically, a) the control vector (|F|,θ F ) is converted into the components (Fα, Fβ) in the α-β coordinate system, and the expressions are Fα=|F|*cos(θF); Fβ=|F|*sin(θF);

[0121] b) Perform Park transformation to obtain the flux component Fd and the torque component Fq, expressed as Fd = Fα*cos(θe)+Fβ*sin(θe); Fq = -Fα*sin(θe)+Fβ*cos(θe); where θe is the electrical angle of the motor.

[0122] S133, calculating the action time of two adjacent basic vectors based on the decomposed components;

[0123] Specifically, a) determine the sector N (N = 1, 2, ..., 6) where the control vector is located; b) calculate the action time of two adjacent basic vectors, the expression is:

[0124]

[0125] T0=T s -T1-T2;

[0126] In the formula, T0 is the action time of the zero vector, T1 and T2 are the action times of two adjacent non-zero vectors, and F max is the maximum output force of the system, T s is the switching cycle.

[0127] S134. Generate a basic vector sequence for nozzle deflection according to the calculated action time.

[0128] Specifically, a) the switching order and duration of the basic vector are determined according to the sector N and the action time T1, T2, and T0; b) a PWM signal sequence is generated to control the switching state of the three-phase inverter; c) the PWM signal is converted into a control signal to drive two servo motors to achieve precise deflection control of the nozzle.

[0129] Specifically, according to the calculated action times T1, T2 and T0, the time distribution of the six basic vectors V1 to V6 is determined to form a basic vector sequence {V1, V2, ..., V n}.

[0130] In one embodiment, based on the basic vector of the nozzle deflection, using the improved adaptive prediction compensation and multi-level control strategy, generating the control instruction includes the following steps:

[0131] S21, establishing a nozzle motion prediction equation based on the basic vector of nozzle deflection;

[0132] S22, updating the control parameters using an adaptive prediction compensation algorithm according to the nozzle motion prediction result;

[0133] S23. Based on the updated control parameters, a multi-level control strategy is used to generate a control instruction for the nozzle deflection, wherein the control instruction for the nozzle deflection includes an orthogonal axis voltage instruction and a direct axis voltage instruction.

[0134] In one embodiment, establishing a nozzle motion prediction equation based on the basic vector of nozzle deflection includes the following steps:

[0135] S211, calculating an equivalent voltage vector according to a basic vector for nozzle deflection control;

[0136] Specifically, based on the nozzle deflection control basic vector sequence {V1, V2, ..., V n}, calculate the equivalent voltage vector V eq , the expression is V eq =(1 / T s )×Σ(V i ×T i );where T s is the switching period, T i is the action time of the ith basis vector.

[0137] S212, calculating the motor torque based on the equivalent voltage vector;

[0138] Specifically, using the equivalent voltage vector V eq , establish the motor torque equation and calculate the motor torque T e , the expression is T e =(3 / 2)×p×(ψf ×i q +(L d -L q )*i d *i q ), where p is the pole pair number, ψ f is the permanent magnet flux, L d and L q is the d-axis and q-axis inductance, i d and i q are the d-axis and q-axis currents.

[0139] S213, based on the motor torque T e , based on the torque balance equation, the nozzle motion prediction equation is established.

[0140] Specifically, using the motor torque T e According to the moment balance equation, the nozzle motion prediction equation is established, and the expression is dω / dt=(K t / J)×T e -(B / J)×ω-(1 / J)×T L (θ,ω); dθ / dt=ω; where t is the nozzle movement time, K t is the torque constant, J is the nozzle moment of inertia, T e is the motor torque, B is the damping coefficient, T L (θ, ω) is the load torque, θ is the nozzle deflection angle, and ω is the nozzle angular velocity.

[0141] In one embodiment, based on the prediction result of the nozzle movement, using the adaptive prediction compensation algorithm, updating the control parameters includes the following steps:

[0142] S221, calculating the predicted value of the nozzle position based on the nozzle motion prediction equation;

[0143] Specifically, the nozzle motion prediction equation established in step S213 is used to calculate the nozzle position prediction value θ(k+1) by numerical integration method, and the expression is:

[0144] ω(k+1)=ω(k)+T s ×(a×T e (k)-b×ω(k)-c×T L (θ(k),ω(k)));

[0145] θ(k+1)=θ(k)+(T s / 2)×(ω(k)+ω(k+1));

[0146] Where θ(k+1) is the predicted value of the nozzle position at the next moment; ω(k+1) is the predicted value of the nozzle angular velocity at the next moment; θ(k) is the actual position of the nozzle at the current moment; ω(k) is the actual angular velocity of the nozzle at the current moment; T s is the switching cycle; Te(k) is the motor torque at the current moment; T L (θ(k), ω(k)) is the load torque at the current moment; a is the motor torque control parameter; b is the damping control parameter; c is the load torque control parameter; k represents the current moment, and k+1 represents the next moment.

[0147] S222, calculating the prediction error according to the nozzle position prediction value;

[0148] Specifically, the nozzle position prediction value θ(k+1) calculated in step S221 and the actual measured value θ m (k+1), calculate the prediction error e(k+1), the expression is e(k+1)=θ m (k+1)-θ(k+1).

[0149] S223. Based on the prediction error, the control parameters are optimized using an adaptive algorithm.

[0150] Specifically, a) using the prediction error e(k+1) calculated in step S222, the control parameters are optimized according to the adaptive algorithm, and the expression is:

[0151] a(k+1)=a(k)+γ a ×e(k+1)×T e (k);

[0152] b(k+1)=b(k)-γ b ×e(k+1)×ω(k);

[0153] c(k+1)=c(k)-γ c ×e(k+1)×T L (θ(k),ω(k));

[0154] Where a(k+1), b(k+1), c(k+1) are the updated motor torque control parameters, damping control parameters and load torque control parameters respectively; a(k), b(k), c(k) are the three corresponding current control parameters; γ a ,γ b ,γ c are three corresponding adaptive gain coefficients; T e (k) is the motor torque at the current moment (unit: N·m); ω(k) is the nozzle angular velocity at the current moment; TL(θ(k), ω(k)) is the load torque at the current moment.

[0155] Specifically, b) update the load compensation function, the expression is:

[0156] T L (θ(k+1),ω(k+1))=T L (θ(k),ω(k))+γ L *e(k+1)*sign(ω(k));

[0157] Where TL(θ(k+1),ω(k+1)) is the updated load torque estimate; T L (θ(k),ω(k)) is the current load torque estimate; γ L is the adaptive gain coefficient of load compensation; sign(·) is the sign function.

[0158] In one embodiment, based on the updated control parameters, using a multi-level control strategy, generating a control instruction for nozzle deflection includes the following steps:

[0159] S231, generating a desired orthogonal axis current using a position control layer strategy according to the updated control parameters;

[0160] Specifically, according to the target deflection angle and the current actual deflection angle Using the position control layer strategy, the desired q-axis current iq* is first generated, expressed as

[0161]

[0162] Then calculate the feedforward compensation term iq ff , the expression is

[0163]

[0164] In the formula, are the proportional parameter, integral parameter and differential parameter of the position controller respectively; s is the Laplace operator, which is used to represent the integral operation; J is the moment of inertia; K t is the torque constant; B is the damping coefficient; TL pred To predict the load torque.

[0165] S232, generating an orthogonal axis voltage command based on the desired orthogonal axis current using a torque control layer strategy;

[0166] Specifically, according to the expected orthogonal axis current iq* and the actual orthogonal axis current iq, the orthogonal axis voltage command uq is generated by using the torque control layer strategy, and the expression is:

[0167] uq=(Kp q +Ki q / s)(iq-iq)+ωe×(Ld ×i d +ψ f );where Kp q and Ki q is the torque controller parameter, ωe is the electrical angular velocity, Ld is the d-axis inductance, id is the d-axis current, ψ f is the permanent magnet flux.

[0168] S233. Generate a direct shaft voltage command based on the direct shaft current and using the flux control layer strategy.

[0169] Specifically, a) according to the expected direct shaft current id* (set to 0 in this embodiment) and the actual direct shaft current id, the direct shaft voltage command ud is generated by using the flux control layer strategy, and the expression is ud = (Kp d +Ki d / s)(id*-id)–ωe×Lq×iq; where, Kp d and Ki d is the flux controller parameter, Lq is the q-axis inductance; b) output control instructions ud and uq for subsequent drive signal generation.

[0170] In one embodiment, according to the control instruction, using the space vector pulse width modulation technology, outputting the driving signal of the servo motor includes the following steps:

[0171] S31, based on the control instruction, using coordinate transformation to obtain the voltage component in the stationary coordinate system;

[0172] It should be noted that the stationary coordinate system (α-β coordinate system) is a stationary two-phase coordinate system commonly used in motor control, also known as the Clarke coordinate system. It is a transformation from a three-phase stationary coordinate system to a two-phase stationary coordinate system. This coordinate system is a stationary coordinate system fixed to the motor stator; at the same time, it can convert three-phase quantities (a, b, c) into two-phase quantities (α, β), which simplifies calculation and control.

[0173] Specifically, a) according to the direct axis voltage command ud and the orthogonal axis voltage command uq obtained in step S23, the voltage components (uα, uβ) in the α-β coordinate system are obtained by inverse Park transformation, and the expressions are uα=ud×cos(θ)-uq×sin(θ); uβ=ud×sin(θ)+uq×cos(θ); wherein θ is the motor rotor position angle;

[0174] b) Based on the voltage components in the α-β coordinate system, calculate the amplitude |U| and angle θ of the synthetic voltage vector u , the expression is

[0175]

[0176] θ u =arctan(uβ,uα).

[0177] S32, calculating the action time of the switch state according to the voltage component in the stationary coordinate system using the principle of space vector pulse width modulation;

[0178] Specifically, a) according to the angle θ of the voltage vector u , determine the sector N (N = 1, 2, ..., 6) where the voltage vector is located, the expression is N = 1 + floor (3θ u / π); b) using the magnitude |U| and angle θ of the synthetic voltage vector u , calculate the action time of two adjacent switch states, the expression is:

[0179]

[0180] T0=T s -Ta-Tb;

[0181] Where, T a is the action time of the first effective vector, indicating the first basic vector in the sector; T b is the action time of the second effective vector, indicating the second basic vector in the sector; T0 is the total action time of the zero vector, used to adjust the amplitude of the output voltage; T s is the switching period; Udc is the DC bus voltage.

[0182] S33. Based on the action time of the switch state, a modulation algorithm is used to output a driving signal of the servo motor.

[0183] Specifically, an optimized PWM drive sequence is generated according to the determined sector N and the calculated action times Ta, Tb, and T0. For sector N, a corresponding switching sequence is determined (for example, when N=1, the sequence is 000-100-110-111-110-100-000), and the duration of each switching state is calculated according to T0, Ta, and Tb.

[0184] Specifically, the generated PWM drive sequence is output to the power module to convert the switch sequence into a high and low level sequence of three phases (A, B, C), and a PWM waveform is generated according to the high and low level sequence and the corresponding duration.

[0185] Specifically, based on the generated PWM waveform, the final driving signal is output through the power module to control the movement of the servo motor and achieve precise nozzle deflection control.

[0186] In summary, with the help of the above technical scheme of the present invention, by innovatively combining space vector voltage synthesis, coordinate transformation, adaptive prediction compensation and multi-level control strategy, the limitations of traditional PID control in nonlinear systems are effectively overcome, the difficulty of implementing complex intelligent control algorithms is avoided, and the dependence of visual feedback methods on the environment is broken; not only the accuracy and response speed of nozzle control are improved, but also the system implementation process is simplified and the maintenance cost is reduced. By fully considering the dynamic characteristics of the nozzle, the present invention can achieve precise control in high-speed motion, meet the strict requirements of modern high-speed inkjet printing systems, and provide a new and efficient solution for nozzle control technology. The scheme has shown obvious advantages in terms of control performance, system implementation and application adaptability. By introducing the improved double-link inverse kinematics equation and dynamic compensation term, the present invention can more accurately predict and control the position of the nozzle, effectively improving the control accuracy. It not only considers the static position of the nozzle, but also takes into account dynamic factors such as speed and acceleration, so that the control system can better cope with nonlinear changes in high-speed motion. Secondly, the basic vector is generated by adopting the principle of space vector voltage synthesis, combined with coordinate transformation technology, to achieve precise control of nozzle deflection. This method overcomes the limitations of traditional PID control in dealing with complex nonlinear systems and can be used in various High-precision control is maintained under working conditions; in addition, by introducing an adaptive predictive compensation algorithm, the control parameters can be dynamically adjusted according to the actual operating conditions, further improving the accuracy and robustness of the control. The application of multi-level control strategies, including position control, torque control and flux control, can comprehensively and accurately control the movement of the nozzle, which not only improves the control accuracy, but also optimizes the operating efficiency of the motor; the comprehensive application of these technologies enables the present invention to always maintain high-precision nozzle control in a high-speed and complex working environment, significantly improving the overall performance; the present invention avoids the cumbersome parameter adjustment process in the traditional intelligent control algorithm by reasonably designing the control structure, greatly The difficulty of implementing the system is simplified and the development cost is reduced; secondly, the introduction of the adaptive prediction compensation algorithm can automatically adapt to different working conditions without frequent manual intervention, thereby enhancing the adaptability and stability of the system. This feature enables the present invention to be widely used in different types of inkjet printing equipment and has good versatility; furthermore, the present invention does not rely on a complex visual feedback system and gets rid of the dependence on ambient light and image processing algorithms, so that the nozzle can maintain stable performance in various application scenarios; in addition, by adopting the space vector pulse width modulation technology, it can quickly generate accurate drive signals, improve the real-time control, and meet the needs of high-speed printing;Finally, the present invention fully considers the dynamic characteristics of the nozzle, and realizes precise control of the nozzle in high-speed motion by establishing an accurate motion prediction equation. This method of comprehensively considering the dynamic characteristics of the system improves the control accuracy, enhances stability and reliability, and makes the technical solution more adaptable and has a wider application prospect in practical applications. ;

[0187] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for intelligent control of nozzle deflection based on vector control, characterized in that: The nozzle deflection intelligent control method based on vector control comprises the following steps: S1. Use space vector voltage synthesis and coordinate transformation to construct the basic vector for nozzle deflection; S2, based on the basic vector of nozzle deflection, using improved adaptive prediction compensation and multi-level control strategy, generate control instructions; S3, according to the control instruction, using the space vector pulse width modulation technology, output the driving signal of the servo motor; The method of constructing the basic vector of nozzle deflection by using space vector voltage synthesis and coordinate transformation includes the following steps: S11, based on the nozzle position information, using the improved double-link inverse kinematics equation, obtaining the target deflection angle of the nozzle; S12, based on the target deflection angle, using the nozzle deflection control equation to obtain the control vector required for the nozzle deflection; S13. Based on the control vector, the basic vector for nozzle deflection is generated by utilizing the space vector voltage synthesis principle.

2. According to claim 1, a method for intelligent control of nozzle deflection based on vector control is characterized in that: The method of obtaining the target deflection angle of the nozzle based on the nozzle position information and using the improved double-link inverse kinematics equation comprises the following steps: S111, using a sensor to obtain nozzle position information, where the nozzle position information includes a current position, a current speed, and a current angular speed of the nozzle; S112, predicting the position of the nozzle at the next moment based on the nozzle position information; S113, calculating the target deflection angle of the nozzle according to the prediction result of the nozzle position at the next moment.

3. The method for intelligent control of nozzle deflection based on vector control according to claim 2, characterized in that: The step of calculating the target deflection angle of the nozzle according to the prediction result of the nozzle position at the next moment comprises the following steps: S1131. Calculate the original deflection angle of the nozzle based on the improved double-link inverse kinematics equation; The expression for calculating the original deflection angle of the nozzle is: θ2=arccos((R 2 +L1 2 -L2 2 ) / (2L1×R)); In the formula, and Respectively represent the position coordinates of the nozzle in the horizontal and vertical directions at the next moment; R represents the distance from the nozzle to the origin; θ1 represents the original angle of the nozzle; θ2 represents the connecting rod angle; L1 represents the length of the first virtual connecting rod; L2 represents the length of the second virtual connecting rod; Indicates the original deflection angle of the sprinkler head; S1132, generating a dynamic compensation item based on the current speed of the nozzle; S1133. Calculate the target deflection angle according to the original deflection angle of the nozzle and the dynamic compensation item.

4. The method for intelligent control of nozzle deflection based on vector control according to claim 1, characterized in that: The method of obtaining the control vector required for the nozzle deflection based on the target deflection angle and using the nozzle deflection control equation comprises the following steps: S121. Establish a nozzle deflection control equation according to the target deflection angle, and calculate the control force required for nozzle deflection; S122, based on the control force required for the nozzle deflection, using trigonometric function decomposition to obtain the horizontal component and the vertical component of the control force; S123. Generate a control vector according to the horizontal component and the vertical component of the control force using the polar coordinate conversion formula.

5. The method for intelligent control of nozzle deflection based on vector control according to claim 1, characterized in that: The method of generating a basic vector for nozzle deflection based on a control vector and utilizing the principle of space vector voltage synthesis comprises the following steps: S131. According to the principle of space vector voltage synthesis, define the basic vector of space vector voltage; S132, using coordinate transformation, decomposing the control vector to obtain magnetic flux components and torque components; S133, calculating the action time of two adjacent basic vectors based on the decomposed components; S134. Generate a basic vector sequence for nozzle deflection according to the calculated action time.

6. The method for intelligent control of nozzle deflection based on vector control according to claim 1, characterized in that: The method of generating control instructions based on the basic vector of nozzle deflection and utilizing improved adaptive prediction compensation and multi-level control strategy includes the following steps: S21, establishing a nozzle motion prediction equation based on the basic vector of nozzle deflection; S22, updating the control parameters using an adaptive prediction compensation algorithm according to the nozzle motion prediction result; S23. Based on the updated control parameters, a multi-level control strategy is used to generate a control instruction for the nozzle deflection, wherein the control instruction for the nozzle deflection includes an orthogonal axis voltage instruction and a direct axis voltage instruction.

7. The method for intelligent control of nozzle deflection based on vector control according to claim 6, characterized in that: The method of establishing the nozzle motion prediction equation based on the basic vector of nozzle deflection comprises the following steps: S211, calculating an equivalent voltage vector according to a basic vector for nozzle deflection control; S212, calculating the motor torque based on the equivalent voltage vector; S213. Based on the motor torque and the torque balance equation, a nozzle motion prediction equation is established.

8. The method for intelligent control of nozzle deflection based on vector control according to claim 6, characterized in that: The updating of control parameters by using an adaptive prediction compensation algorithm according to the nozzle motion prediction result comprises the following steps: S221, calculating the predicted value of the nozzle position based on the nozzle motion prediction equation; S222, calculating the prediction error according to the nozzle position prediction value; S223. Based on the prediction error, the control parameters are optimized using an adaptive algorithm.

9. The method for intelligent control of nozzle deflection based on vector control according to claim 6, characterized in that: The method of generating a control instruction for nozzle deflection based on the updated control parameters and using a multi-level control strategy comprises the following steps: S231, generating a desired orthogonal axis current using a position control layer strategy according to the updated control parameters; S232, generating an orthogonal axis voltage command based on the desired orthogonal axis current using a torque control layer strategy; S233. Generate a direct shaft voltage command based on the direct shaft current and using the flux control layer strategy.

10. The method for intelligent control of nozzle deflection based on vector control according to claim 1, characterized in that: The method of outputting a driving signal of the servo motor by using space vector pulse width modulation technology according to the control instruction comprises the following steps: S31, based on the control instruction, using coordinate transformation to obtain the voltage component in the stationary coordinate system; S32, calculating the action time of the switch state according to the voltage component in the stationary coordinate system using the principle of space vector pulse width modulation; S33. Based on the action time of the switch state, a modulation algorithm is used to output a driving signal of the servo motor.

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