阅读说明：本技术 异构多阀并联驱动电液伺服系统及控制方法 (Heterogeneous multi-valve parallel drive electro-hydraulic servo system and control method ) 是由 苏世杰 潘纬鸣 唐文献 陈赟 薛挺 王真心 于 2020-04-27 设计创作，主要内容包括：本发明公开了一种异构多阀并联驱动电液伺服系统及控制方法,包括柱塞泵,柱塞泵通过多个并联的各个伺服阀和比例阀与液压缸连通,液压缸的活塞杆信号连接位移传感器,位移传感器与控制器的输入端信号连接,控制器的输出端与各个比例阀和伺服阀信号连接,控制器根据油量剩余总量按照比例阀和伺服阀的工作优先级进行分配,根据分配的油量设置控制电压。本发明通过通过多阀并联协调控制方法弥补了比例阀存在的死区和响应速度慢等问题,在满足高精度、快响应、大流量等性能的同时,还通过异构多阀的并联结构节约了成本,并通过自适应鲁棒算法解决了存在的自适应可调参数和外部干扰等问题。(The invention discloses a heterogeneous multi-valve parallel driving electro-hydraulic servo system and a control method thereof, wherein the heterogeneous multi-valve parallel driving electro-hydraulic servo system comprises a plunger pump, the plunger pump is communicated with a hydraulic cylinder through a plurality of parallel servo valves and proportional valves, a piston rod of the hydraulic cylinder is in signal connection with a displacement sensor, the displacement sensor is in signal connection with an input end of a controller, an output end of the controller is in signal connection with the proportional valves and the servo valves, the controller distributes according to the residual total amount of oil according to the working priority of the proportional valves and the servo valves, and control voltage is set according to the distributed oil. The invention makes up the problems of dead zone, slow response speed and the like of the proportional valve by a multi-valve parallel coordination control method, saves the cost by a parallel structure of heterogeneous multi-valves while meeting the performances of high precision, fast response, large flow and the like, and solves the problems of self-adaptive adjustable parameters, external interference and the like by a self-adaptive robust algorithm.)

1. The utility model provides a heterogeneous many valves drive electricity liquid servo system that connects in parallel which characterized in that, includes the plunger pump, the oil tank is connected to the plunger pump oil inlet, the plunger pump oil-out passes through behind the check valve through branch road intercommunication each parallelly connected servo valve and proportional valve, and the oil return opening of each servo valve and proportional valve passes through pipeline and oil tank intercommunication, and the oil-out of each servo valve and proportional valve passes through pipeline and pneumatic cylinder intercommunication, the piston rod signal connection displacement sensor of pneumatic cylinder, displacement sensor and the input signal connection of controller, the output and each proportional valve and the servo valve signal connection of controller.

2. The heterogeneous multi-valve parallel drive electro-hydraulic servo system as claimed in claim 1, wherein the plunger pump is electrically connected with a three-phase motor, and the three-phase motor controls the plunger pump to work.

3. The heterogeneous multi-valve parallel drive electro-hydraulic servo system as claimed in claim 1, wherein the one-way valve is communicated with an oil tank through an oil return branch, and an overflow valve and an oil filter are arranged on the oil return branch.

4. The control method of the heterogeneous multi-valve parallel drive electro-hydraulic servo system according to claim 1, characterized by comprising the following steps:

(1) the controller calculates and obtains the target displacement x of the current hydraulic cylinder according to the working time T of the system_dAnd to x_dFirst derivative ofSecond derivative of

(2) Calculating to obtain the total flow Q of the hydraulic cylinder according to the obtained target displacement, the displacement deviation and the derivative_y(T), the calculation formula is as follows:

wherein d is_y、M_y、B_y、D_yAnd C_yAll the parameters are self-adaptive adjustable parameters obtained by a hydraulic system through a mathematical model;

(3) taking the total flow obtained in the step (2) for driving the hydraulic cylinder to move as an initial residual total flow, and taking the initial residual total flow Q_yi(T)＝Q_y(T)；

(4) And sequentially distributing the residual total flow to the flow of each proportional valve according to the working priority of each proportional valve, and obtaining the control voltage of the proportional valve in the current control period according to the distributed flow, wherein the control voltage is as follows:

when Q is_yi(T)＞f_i(U_pi(T-t)+ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)+ΔU_pi；

When Q is_yi(T)＜f_i(U_pi(T-t)-ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)-ΔU_pi；

When f is_i(U_pi(T-t)-ΔU_pi)≤Q_yi(T)≤f_i(U_pi(T-t)+ΔU_pi) When is, Q_yi(T) > 0 then the proportional valve P_iIs set to

Wherein the content of the first and second substances,indicating the maximum increment of the control voltage, U, per control cycle_pimaxIndicating the proportional valve P_iMaximum output voltage of, T_piIndicating the proportional valve P_iResponse time of spool, D_iIndicating the proportional valve P_iThe dead zone of (a) is,K_piindicating the proportional valve P_iT denotes a control period, f_i(U_pi(T-t)+ΔU_pi) Indicating the maximum flow f of the proportional valve output of the current control cycle_i(U_pi(T-t)-ΔU_pi) Indicating the minimum flow, U, of the proportional valve output for the current control cycle_pi(T-T) represents the voltage output by the proportional valve for the last control cycle;

(5) the residual flow after the flow of each proportional valve is distributed sequentially distributes the flow of each servo valve according to the working priority of the servo valve, and the control voltage of the servo valve in the current control period is obtained according to the distributed flow, which is specifically as follows:

when g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-t)+ΔU_si；

When Q is_yi(T)＜g_i(U_si(T-t)-ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-t)-ΔU_si；

When g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to

Wherein S is_iIncrement of voltage value ofU_simaxIs a servo valve S_iMaximum output voltage of, T_siServo valve S_iValve element response time, g_i(U_si(T-t)+ΔU_si) Representing the maximum value of the flow that can be output by the servo valve in the current control period, g_i(U_si(T-t)-ΔU_si) Represents the minimum value, U, of the flow that can be output by the servo valve in the current control period_si(T-T) tableDisplaying the output voltage of the servo valve in the last control period;

(6) working time T < T_max0And (3) carrying out control of the next control period, updating the self-adaptive adjustable parameters, and repeating the steps (1) - (5) until T is more than or equal to T_max0The system stops the control.

5. The control method of the heterogeneous multi-valve parallel drive electro-hydraulic servo system according to claim 4, wherein the step (1) is performed according to a preset function x_dF (t) calculating the target displacement of the hydraulic cylinder according to e x_p-x_dAnd calculating the displacement deviation.

6. The control method of the heterogeneous multi-valve parallel drive electro-hydraulic servo system according to claim 4, wherein the step (6) of updating the adaptive adjustable parameters specifically comprises the following steps:

adaptive adjustable parameter M_yAccording to the formulaPerforming updating when updating value M_y＞M_ymaxWhen M is in contact with_y＝M_ymax(ii) a When updating value M_y＜M_yminWhen M is in contact with_y＝M_ymin；

Adaptive adjustable parameter B_yAccording to the formulaPerforming updating when updating value B_y＞B_ymaxWhen, B_y＝B_ymax(ii) a When updating value B_y＜B_yminWhen, B_y＝B_ymin；

Adaptive adjustable parameter C_yAccording to the formulaPerforming updating when updating value C_y＞C_ymaxWhen, C_y＝C_ymax(ii) a When updating value C_y＜C_yminWhen, C_y＝C_ymin；

Adaptive tunable parameter D_yAccording to the formula

Adaptive adjustable parameter d_yAccording to the formula

Wherein M is_ymin、M_ymaxAre respectively M_yMinimum and maximum of, B_ymin、B_ymaxAre respectively B_yMinimum and maximum of, C_ymin、C_ymaxAre respectively C_yMinimum and maximum of, D_ymin、D_ymaxAre respectively D_yMinimum and maximum of d_ymin、d_ymaxAre respectively d_yλ is the system gain.

Technical Field

The invention relates to an electro-hydraulic servo system and control, in particular to a heterogeneous multi-valve parallel driving electro-hydraulic servo system and a control method.

Background

The electro-hydraulic servo is widely applied in industrial production, and along with the technical progress, the requirements on the flow and response speed performance of an electro-hydraulic servo system are higher and higher, so that a large-flow and high-precision electro-hydraulic servo valve is produced. However, the low-speed performance of the high-flow electro-hydraulic servo valve is not ideal and the cost is high. In order to save cost and meet the requirement of high-precision control, the scheme of parallel control by using a plurality of servo valves/proportional valves has certain theoretical and implementation significance.

Chinese patent CN201210467404.2 discloses a "hydraulic parallel speed change-over circuit connection method", which realizes the switching circuit of two times of feeding speeds by connecting two speed regulating valves in parallel and by using the speed regulating valves, and the position control precision of the system is improved by the method. Secondly, the Chinese patent application No. CN200820087129.0 discloses a large-flow high-frequency response electro-hydraulic servo valve based on a parallel pilot stage, the patent provides a method for connecting a plurality of small-flow servo valves in parallel to be equivalent to a large-flow servo valve, then the synchronization of the output flow of each servo valve is realized through a synchronous control algorithm, and the method effectively improves the response precision and the flow of the system.

Although the control accuracy and the response speed of the electro-hydraulic servo system are improved by the methods, the control is usually performed by a synchronous control method because the same valves are connected in parallel, and the synchronous control requires that the performance indexes of the valves in the system are consistent as much as possible, so that the cost of the system is increased and the reliability of the system is reduced.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a heterogeneous multi-valve parallel drive electro-hydraulic servo system and a control method, and solves the problems of high requirements on performance indexes of valves, low reliability and high cost in synchronous control in the conventional multi-valve parallel system.

The technical scheme is as follows: the heterogeneous multi-valve parallel driving electro-hydraulic servo system comprises a plunger pump, wherein an oil inlet of the plunger pump is connected with an oil tank, an oil outlet of the plunger pump is communicated with all parallel servo valves and proportional valves through a one-way valve and then through a branch, oil return ports of all the servo valves and the proportional valves are communicated with the oil tank through pipelines, oil outlets of all the servo valves and the proportional valves are communicated with a hydraulic cylinder through pipelines, a piston rod of the hydraulic cylinder is in signal connection with a displacement sensor, the displacement sensor is in signal connection with an input end of a controller, and an output end of the controller is in signal connection with all the proportional valves and the servo valves.

The plunger pump is electrically connected with a three-phase motor, and the three-phase motor controls the plunger pump to work.

In order to ensure the pipeline pressure on the main oil return pipeline, the one-way valve is communicated with the oil tank through an oil return branch, and the oil return branch is provided with an overflow valve and an oil filter.

The invention relates to a control method of a heterogeneous multi-valve parallel drive electro-hydraulic servo system, which comprises the following steps:

(1) the controller calculates and obtains the target displacement x of the current hydraulic cylinder according to the working time T of the system_dAnd to x_dFirst derivative of

Second derivative ofAnd third derivative

The displacement sensor R collects the actual displacement x at the current moment_pComparing the actual displacement x_pAnd a target displacement x_dObtaining the displacement deviation e and calculating the first derivative of e

Second derivative ofThird derivative

(2) Calculating to obtain the total flow Q of the hydraulic cylinder according to the obtained target displacement, the displacement deviation and the derivative_y(T), the calculation formula is as follows:

wherein d is_y、M_y、B_y、D_yAnd C_yAll the parameters are self-adaptive adjustable parameters obtained by a hydraulic system through a mathematical model;

(3) taking the total flow obtained in the step (2) for driving the hydraulic cylinder to move as an initial residual total flow, and taking the initial residual total flow Q_yi(T)＝Q_y(T)；

(4) And sequentially distributing the residual total flow to the flow of each proportional valve according to the working priority of each proportional valve, and obtaining the control voltage of the proportional valve in the current control period according to the distributed flow, wherein the control voltage is as follows:

when Q is_yi(T)＞f_i(U_pi(T-t)+ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)+ΔU_pi；

When Q is_yi(T)＜f_i(U_pi(T-t)-ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)-ΔU_pi；

When f is_i(U_pi(T-t)-ΔU_pi)≤Q_yi(T)≤f_i(U_pi(T-t)+ΔU_pi) When is, Q_yi(T) > 0 then the proportional valve P_iIs set to

Q_yi(T) < 0, the control voltage is set to

Wherein the content of the first and second substances,indicating the maximum increment of the control voltage, U, per control cycle_pimaxIndicating the proportional valve P_iMaximum output voltage of, T_piIndicating the proportional valve P_iResponse time of spool, D_iIndicating the proportional valve P_iDead zone of, K_piIndicating the proportional valve P_iT denotes a control period, f_i(U_pi(T-t)+ΔU_pi) Indicating the maximum flow f of the proportional valve output of the current control cycle_i(U_pi(T-t)-ΔU_pi) Indicating the minimum flow, U, of the proportional valve output for the current control cycle_pi(T-T) represents the voltage output by the proportional valve for the last control cycle;

(5) the residual flow after the flow of each proportional valve is distributed sequentially distributes the flow of each servo valve according to the working priority of the servo valve, and the control voltage of the servo valve in the current control period is obtained according to the distributed flow, which is specifically as follows:

when g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-t)+ΔU_si；

When Q is_yi(T)＜g_i(U_si(T-t)-ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-t)-ΔU_si；

When g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to

Wherein S is_iIncrement of voltage value ofU_simaxIs a servo valve S_iMaximum output voltage of, T_siServo valve S_iValve element response time, g_i(U_si(T-t)+ΔU_si) Representing the maximum value of the flow that can be output by the servo valve in the current control period, g_i(U_si(T-t)-ΔU_si) Represents the minimum value, U, of the flow that can be output by the servo valve in the current control period_si(T-T) represents the output voltage of the servo valve in the last control period;

(6) working time T < T_max0And (3) carrying out control of the next control period, updating the self-adaptive adjustable parameters, and repeating the steps (1) - (5) until T is more than or equal to T_max0The system stops the control.

Wherein, the step (1) is according to a preset function x_dF (t) calculating the target displacement of the hydraulic cylinder according to e x_p-x_dAnd calculating the displacement deviation.

The step (6) of updating the adaptive adjustable parameters specifically comprises the following steps:

adaptive adjustable parameter M_yAccording to the formulaPerforming updating when updating value M_y＞M_ymaxWhen M is in contact with_y＝M_ymax(ii) a When updating value M_y＜M_yminWhen M is in contact with_y＝M_ymin；

Adaptive adjustable parameter B_yAccording to the formula

Performing updating when updating value B_y＞B_ymaxWhen, B_y＝B_ymax(ii) a When updating value B_y＜B_yminWhen, B_y＝B_ymin；

Adaptive adjustable parameter C_yAccording to the formulaPerforming updating when updating value C_y＞C_ymaxWhen, C_y＝C_ymax(ii) a When updating value C_y＜C_yminWhen, C_y＝C_ymin；

Adaptive tunable parameter D_yAccording to the formula

Updating is carried out when the value D is updated_y＞D_ymaxWhen D is_y＝D_ymax(ii) a When updating value D_y＜D_yminWhen D is_y＝D_ymin；

Adaptive adjustable parameter d_yAccording to the formulaPerforming updating when the updated value d is_y＞d_ymaxWhen d is greater than_y＝d_ymax(ii) a When updating value d_y＜d_yminWhen d is greater than_y＝d_ymin；

Wherein M is_ymin、M_ymaxAre respectively M_yMinimum and maximum of, B_ymin、B_ymaxAre respectively B_yMinimum and maximum of, C_ymin、C_ymaxAre respectively C_yMinimum and maximum of, D_ymin、D_ymaxAre respectively D_yMinimum and maximum of d_ymin、d_ymaxAre respectively d_yλ is the system gain.

Has the advantages that: the invention makes up the problems of dead zone, slow response speed and the like of the proportional valve by a multi-valve parallel coordination control method, saves the cost by a parallel structure of heterogeneous multi-valves while meeting the performances of high precision, fast response, large flow and the like, and solves the problems of self-adaptive adjustable parameters, external interference and the like by a self-adaptive robust algorithm.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic control flow diagram of the present invention;

FIG. 3 is a simulation diagram incorporating the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the heterogeneous multi-valve parallel drive electro-hydraulic servo system mainly includes: plunger pump 6, three-phase motor 7, proportional valve P ₁3. Proportional valve P₂… … proportional valve P _m2, servo valve S _m+19. Servo valve S_m+2… … Servo valve S _n10, a check valve 8, a hydraulic cylinder 1, an overflow valve 4, a displacement sensor 12, a controller 11 and an oil filter 5. The three-phase motor 7 is connected with the plunger pump 6, an oil inlet of the plunger pump 6 is connected with the oil tank, the three-phase motor rotates to drive the plunger pump to work, and the plunger pump starts to supply oil to the hydraulic system; the output hydraulic oil flows to the one-way valve through an oil outlet of the plunger pump, flows to the oil filter through the one-way valve, and then flows to an oil inlet of each servo valve and an oil inlet of each proportional valve through the high-pressure hose. The overflow valve is arranged on the main oil return pipeline to ensure the pipeline pressure, and the hydraulic oil is connected with the high-pressure hose through the oil return ports of each servo valve and each proportional valve and flows to the oil tank. The hydraulic cylinder is connected with the oil outlet of each servo valve and the oil outlet of each proportional valve, and a piston rod of the hydraulic cylinder is connected with the displacement sensor; the signal output end of the displacement sensor 12 is connected with the input end of the controller 11, and n output ends of the controller 11 are respectively connected with the proportional valve P₁……P_mControl signal input and servo valve S_m+1……S_nThe control signal input ends are connected.

The control method of the invention specifically comprises the following steps:

(1) the controller calculates and obtains the target displacement x of the current hydraulic cylinder according to the working time T of the system_d，x_dF (t), and for x_dFirst derivative of

Second derivative of

And third derivativeThe displacement sensor R collects the actual displacement x at the current moment_pAccording to e ═ x_p-x_dObtaining the displacement deviation e and calculating the first derivative of e

Second derivative of

Third derivative

(2) And calculating the total flow for driving the hydraulic cylinder to move according to the obtained target displacement, the displacement deviation and the derivative, wherein the calculation formula is as follows:

wherein d is_y、M_y、B_y、D_yAnd C_yAll the parameters are self-adaptive adjustable parameters obtained by a hydraulic system through a mathematical model;

(3) taking the total flow of the hydraulic cylinder driven to move in the step (2) as an initial residual total flow, and taking the initial residual total flow Q_yi(T)＝Q_y(T)；

(4) And sequentially distributing the residual total flow to the flow of each proportional valve according to the working priority of each proportional valve, and obtaining the control voltage of the proportional valve in the current control period according to the distributed flow, wherein the control voltage is as follows:

when Q is_yi(T)＞f_i(U_pi(T-t)+ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)+ΔU_pi；

When Q is_yi(T)＜f_i(U_pi(T-t)-ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)-ΔU_pi；

When f is_i(U_pi(T-t)-ΔU_pi)≤Q_yi(T)≤f_i(U_pi(T-t)+ΔU_pi) When is, Q_yi(T) > 0 then the proportional valve P_iIs set to

Q_yi(T) < 0, the control voltage is set to

Wherein the content of the first and second substances,

indicating the maximum increment of the control voltage, U, per control cycle_pimaxIndicating the proportional valve P_iMaximum output voltage of, T_piIndicating the proportional valve P_iResponse time of spool, D_iIndicating the proportional valve P_iDead zone of, K_piIndicating the proportional valve P_iT denotes a control period, f_i(U_pi(T-t)+ΔU_pi) Indicating the maximum flow f of the proportional valve output of the current control cycle_i(U_pi(T-t)-ΔU_pi) Indicating the minimum flow, U, of the proportional valve output for the current control cycle_pi(T-T) represents the voltage output by the proportional valve for the last control cycle;

(5) the residual flow after the flow of each proportional valve is distributed sequentially distributes the flow of each servo valve according to the working priority of the servo valve, and the control voltage of the servo valve in the current control period is obtained according to the distributed flow, which is specifically as follows:

when g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-1)+ΔU_si；

When Q is_yi(T)＜g_i(U_si(T-t)-ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-1)-ΔU_si；

When g is_i(U_si(T-t)-ΔU_si)≤Q_yi(T)≤g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to

Wherein S is_iIncrement of voltage value ofU_simaxIs a servo valve S_iMaximum output voltage of, T_siServo valve S_iValve element response time g_i(U_si(T-t)+ΔU_si) Representing the maximum value of the flow that can be output by the servo valve in the current control period, g_i(U_si(T-t)-ΔU_si) Represents the minimum value, U, of the flow that can be output by the servo valve in the current control period_si(T-T) represents the output voltage of the servo valve in the last control period;

(6) working time T < T_max0Then, the next control period is controlled, the self-adaptive adjustable parameters are updated, and then the steps (1) - (5) are repeated until T is more than or equal to T_max0And the system stops control, and the updating of the self-adaptive adjustable parameters specifically comprises the following steps:

adaptive adjustable parameter M_yAccording to the formulaPerforming updating when updating value M_y＞M_ymaxWhen M is in contact with_y＝M_ymax(ii) a When updating value M_y＜M_yminWhen M is in contact with_y＝M_ymin；

Adaptive adjustable parameter B_yAccording to the formulaPerforming updating when updating value B_y＞B_ymaxWhen, B_y＝B_ymax(ii) a When updating value B_y＜B_yminWhen, B_y＝B_ymin；

Adaptive adjustable parameter C_yAccording to the formulaPerforming updating when updating value C_y＞C_ymaxWhen, C_y＝C_ymax(ii) a When updating value C_y＜C_yminWhen, C_y＝C_ymin；

Adaptive tunable parameter D_yAccording to the formula

Updating is carried out when the value D is updated_y＞D_ymaxWhen D is_y＝D_ymax(ii) a When updating value D_y＜D_yminWhen D is_y＝D_ymin；

Adaptive adjustable parameter d_yAccording to the formulaPerforming updating when the updated value d is_y＞d_ymaxWhen d is greater than_y＝d_ymax(ii) a When updating value d_y＜d_yminWhen d is greater than_y＝d_ymin；

Wherein M is_ymin、M_ymaxAre respectively M_yMinimum and maximum of, B_ymin、B_ymaxAre respectively B_yMinimum and maximum of, C_ymin、C_ymaxAre respectively C_yMinimum and maximum of, D_ymin、D_ymaxAre respectively D_yMinimum and maximum of d_ymin、d_ymaxAre respectively d_yλ is the system gain.

When carrying out simulation test aiming at the system:

(1) numbering the proportional valves according to the response speeds of the proportional valves, wherein the proportional valve with the slowest response speed is numbered as P₁The proportional valve number of the response time is P₂,., the proportional valve with the fastest response is numbered P_m. Numbering the servo valves according to the response speeds of the servo valves, wherein the servo valve with the slowest response speed is numbered S_m+1The servo valve number with the second slowest response is S_m+2,., the servo valve with the fastest response is numbered S_n. The priority of operation of the proportional valve and the servo valve is thus P₁＞P₂＞...＞P_m＞S_m+1＞S_m+2＞...＞S_nThe control period t is 1 ms; working time T; total working time T_max(ii) a Total flow Q of the system_y(T), proportional valve P_iControl voltage U of_pi(T), output flow rate Q_pi(T), wherein i represents the serial number of the valve, i is more than or equal to 1 and less than or equal to m; servo valve S_iControl voltage U of_si(T), output flow rate Q_si(T), wherein i represents the serial number of the valve, and m +1 is not less than i not more than n; target displacement x of hydraulic cylinder H_d，x_dF (T) is a function that varies with the operating time T. Each control period of the system calculates the target displacement x at the current moment according to the working time T_d(ii) a Actual trajectory x of hydraulic cylinder H_pAnd each control cycle of the system can carry out actual displacement x through the displacement sensor_pSampling is carried out; the target displacement x is obtained in each control cycle of the system_dAnd the actual displacement x_pTaking the difference to obtain the displacement deviation, i.e. e ═ x_p-x_dPresetting a system adaptive adjustable parameter M_y，M_ymin、M_ymaxAre respectively M_yMinimum and maximum, system adaptive adjustable parameter B_y，B_ymin、B_ymaxAre respectively B_yMinimum and maximum, system adaptive adjustable parameter C_y，C_ymin、C_ymaxAre respectively C_yMinimum and maximum, system adaptive adjustable parameter D_y，D_ymin、D_ymaxAre respectively D_yMinimum and maximum values of; system adaptive adjustable parameter d_y， d_ymin、d_ymaxAre respectively d_yMinimum and maximum values of; the system gain is lambda;

the proportional valve P being dependent on the physical characteristics of the proportional valve_iOutput flow rate Q of_pi(T) and a control voltage U_pi(T) formula:

k in formula ①_piIndicating the proportional valve P_iGain of (D)_iIndicating the proportional valve P_iWherein i is more than or equal to 1 and less than or equal to m.

Setting proportional valve P_iHas a maximum output voltage of U_pimaxProportional valve P_iValve core response time of T_piProportional valve P_iHas a voltage value increment of

Defining the servo valve S according to the physical characteristics of the servo valve_iOutput flow rate Q of_si(T) and a control voltage U_si(T) formula:

Q_si(T)＝g_i(U_i(T))＝K_siU_si(T) ②

k in formula ②_siIndicating a servo valve S_iWherein m +1 is not less than i not more than n.

Servo valve S_iHas a maximum output voltage of U_simaxA servo valve S_iValve core response time of T_si，S_iIncrement of voltage value of

(2) Initializing the parameters, specifically:

working time T is 0 ms; total working time T_max300 ms; control voltage U of proportional valve_pi(T) ═ 0V, where i ═ 1, 2, 3, …, m; control voltage U of servo valve_si(T) ═ 0V, where i ═ m +1, m +2, m +3, …, n; m_y0＝4.5×10^-7，M_ymin＝1×10^-7、M_ymax＝10×10^-7；B_y0＝8.5×10^-5，B_ymin＝1×10^-5、B_ymax＝9×10^-5；C_y0＝0.36，C_ymin＝0.1、C_ymax＝0.6；D_y0＝5.3×10^-7，D_ymin＝1×10^-7、D_ymax＝10×10^-7；d_y0＝0， d_ymin＝-10×10^-7、d_ymax＝10×10^-7；λ₀110; initialization x_dAnd the function F (T) is a slope curve with 20 slope and 1mm amplitude.

(3) The system starts/continues to work, and the working time T is T + 1. System according to function x_dF (t) calculating the current target displacement x_dAnd to x_dFirst derivative ofSecond derivative ofThird derivativeMeanwhile, the displacement sensor R collects the actual displacement x at the current moment_pAnd sends it to the motion control card C; the system calculates the displacement deviation e and calculates the first derivative thereof

Second derivative of

Third derivative

(4) According to the formulaCalculating the current sumFlow rate Q_y(T)。

(5) The system is used for obtaining the total flow Q in the step (4)_y(T) carrying out flow distribution.

Let Q_yi(T) is the residual flow, let Q_yi(T)＝Q_y(T), i is 1, and the process proceeds to step (5.1).

(5.1) the system distributes flow to each proportional valve according to the operating priority of the proportional valve:

(5.1.1) when Q_yi(T)＞f_i(U_pi(T-t)+ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)+ΔU_pi。

(5.1.2) when Q is_yi(T)＜f_i(U_pi(T-t)-ΔU_pi) While, the proportional valve P_iIs set to U_pi(T)＝U_pi(T-t)-ΔU_pi。

(5.1.2) cases of dividing (5.1.1) and (5.1.2), when Q is_yi(T) > 0 proportional valve P_iIs set toWhen Q is_yiWhen (T) < 0, the control voltage is set to

(5.1.4) the flow is then further dispensed by the next proportional valve, i.e. i + 1. The system is based on formula Q_yi(T)＝Q_y(i-1)(T)-f_(i-1)(U_p(i-1)(T)) calculating the residual flow rate and returning to step (5.1.1). Until i > m, proceed to step (5.2).

(5.2) the system distributes the residual flow to each servo valve according to the working priority of the servo valve:

(5.2.1) when Q_yi(T)＞g_i(U_si(T-t)+ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-1)+ΔU_si；

(5.2.2) when Q is_yi(T)＜g_i(U_si(T-t)-ΔU_si) Time, servo valve S_iIs set to U_si(T)＝U_si(T-1)-ΔU_si；

(5.2.3) otherwise, the servo valve S_iIs set to

(5.2.4) then the next servo valve continues to dispense flow, i.e., i +1, the system follows equation Q_yi(T)＝Q_y(i-1)(T)-f_(i-1)(U_p(i-1)(T)) calculating the residual flow rate, returning to step (5.2.1) until i>When n, go to step (6).

(6) The system updates the adaptive adjustable parameters of the next control period.

(7) And (4) returning to the step (3) if the working time T is less than 300ms, and automatically stopping control and setting the control signal output of all valves to be 0 if T is more than or equal to 300 ms.

The simulation result is shown in fig. 3, and it can be seen from fig. 3 that the response speed and tracking accuracy of the tracking curve of the control method of the invention are obviously improved compared with the existing single-valve PID control method.