Parameter matching and optimization method of valve-controlled hydraulic driver for non-smooth load trajectory

Abstract

The application discloses a valve-controlled hydraulic driver parameter matching and optimization method for a non-smooth load trajectory, and the method comprises the following steps: determining an expression equivalent to a load from a retracted working condition to an extended working condition of a hydraulic driver according to an effective pressure of a hydraulic system; determining a parameter to be solved of the load equivalent expression according to a load power distribution, and performing load equivalence; determining a close envelope method of an output characteristic curve of the hydraulic driver to the equivalent load trajectory based on the equivalent load trajectory, and matching the hydraulic driver parameter; and optimizing the hydraulic driver parameter suitable for machining and selection based on a speed square stiffness of the hydraulic driver. The method can widen the application range of the existing hydraulic driver parameter matching method, and can perform parameter matching on the non-smooth load trajectory. Meanwhile, the application provides a hydraulic driver parameter optimization method for machining and selection, so as to ensure that the hydraulic driver used in engineering can meet the demand of driving the load.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic technology, particularly the field of hydraulic servo technology, and specifically relates to a method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories. Background Technology

[0002] Hydraulic technology is one of the key technologies in modern transmission and control, possessing advantages such as a high power-to-weight ratio, fast response speed, and high control precision, holding an irreplaceable position in both military and civilian fields. Compared to pump-controlled hydraulic systems, valve-controlled hydraulic systems offer higher dynamic response, primarily consisting of a hydraulic oil source and a hydraulic actuator. The hydraulic oil source generates high-pressure hydraulic oil, while the hydraulic actuator drives the load. The parameters of the hydraulic actuator are calculated and matched based on the load trajectory (the curve formed by load force and load velocity in the force-velocity plane). If the matched hydraulic actuator parameters are unsuitable, the hydraulic actuator cannot fully drive the load, leading to malfunction of the hydraulic system. Therefore, matching the hydraulic actuator parameters is particularly important in the system design process.

[0003] In various valve-controlled hydraulic systems, the load trajectory under actual operating conditions is usually a non-smooth curve. Combining the working characteristics of the hydraulic actuator, and taking the extension of the hydraulic actuator piston rod as the positive direction, the hydraulic actuator and its load can be divided into four operating conditions: resistance extension condition (the load is positive, the hydraulic actuator does positive work, and the directions of its force and velocity are both positive), resistance retraction condition (the load is positive, the hydraulic actuator does positive work, and the directions of its force and velocity are both negative), overrun extension condition (the load is negative, the hydraulic actuator does negative work, the direction of its force is negative, and the direction of its velocity is positive), and overrun retraction condition (the load is negative, the hydraulic actuator does negative work, the direction of its force is positive, and the direction of its velocity is negative).

[0004] The traditional method for matching hydraulic actuator parameters was proposed by American engineer Merritt in "Hydraulic Control Systems". This method is mainly aimed at the impedance extension condition of hydraulic actuators and the corresponding smooth load trajectory. The hydraulic actuator parameters are matched by coinciding the maximum power point of the hydraulic actuator output characteristic curve with the maximum power point of the load trajectory. Then, the envelope of the hydraulic actuator output characteristic curve to the load trajectory is verified under other conditions. If it cannot completely enclose the load trajectory, the hydraulic actuator parameters need to be increased to meet the requirements of the hydraulic actuator driving the load. This process is repeated iteratively until suitable hydraulic actuator parameters are matched.

[0005] In summary, comparing existing hydraulic actuator parameter matching methods with actual requirements reveals the following two limitations:

[0006] 1. It is difficult to apply to non-smooth load trajectories with general characteristics, and the matching process for the four operating conditions of hydraulic actuators is complex.

[0007] 2. The hydraulic actuator parameters obtained from matching are difficult to directly apply to the processing and selection of its components, and there is a lack of methods for optimizing hydraulic actuator parameters. Summary of the Invention

[0008] The purpose of this invention is to provide a method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories, so as to overcome the limitations of existing hydraulic actuator parameter matching methods. This invention is also applicable to parameter matching of valve-controlled hydraulic motors / oscillating cylinders.

[0009] The non-smooth load trajectory refers to the non-smooth load trajectory formed under actual working conditions due to the irregular motion requirements of the load and the superposition of different types of load forces. The corresponding smooth load trajectory is a special case of the non-smooth load trajectory. The hydraulic actuator parameter optimization method refers to further optimizing the hydraulic actuator parameters according to the processing and selection requirements of the parts, so that the optimized hydraulic actuator still meets the driving requirements of the load.

[0010] To achieve the above objectives, the present invention provides the following solution:

[0011] (1) Based on the effective pressure of the hydraulic system, determine the equivalent expression of the hydraulic actuator retracted load to the extended load; including: the equivalent expression of the load force and load speed of the hydraulic actuator resistive retracted load to the resistive extended load, and the equivalent expression of the load force and load speed of the hydraulic actuator over-retracted load to the over-extended load.

[0012] (2) Based on the load power distribution, determine the parameters to be determined in the load equivalent expression (the ratio of the two chamber areas of the hydraulic actuator and hydraulic cylinder); convert the retracted load of the hydraulic actuator into the extended load to obtain the equivalent load trajectory.

[0013] (3) Based on the equivalent post-load trajectory, determine the tight envelope method of the hydraulic actuator output characteristic curve to the equivalent post-load trajectory, and match the hydraulic actuator parameters; the hydraulic actuator output characteristic curve is divided into the relationship between force and velocity in the force-velocity (Fv) plane, and the relationship between force and velocity square (Fv) plane. 2 The relationship between force and the square of velocity in a plane;

[0014] (4) Based on the speed square stiffness of the hydraulic actuator, optimize the hydraulic actuator parameters suitable for processing and selection; the speed square stiffness is the reciprocal of the slope of the output characteristic curve of the hydraulic actuator in the force-speed square plane.

[0015] Further, in step (1), the effective pressure of the hydraulic system is the maximum effective pressure that the hydraulic system can provide to the hydraulic actuator.

[0016] Furthermore, based on the effective pressure of the hydraulic system, the equivalent expression for the hydraulic actuator's retracted load to its extended load is determined, specifically including:

[0017] Based on the effective pressure of the hydraulic system, determine the output characteristic expressions of the hydraulic actuator under impedance and overrun conditions;

[0018] Based on the power properties of the hydraulic actuator and the load, determine the equivalent load expression for the hydraulic actuator retracted load to the hydraulic actuator extended load.

[0019] Furthermore, based on the load power distribution, the parameters to be determined in the load equivalent expression are identified, and load equivalence is performed, specifically including:

[0020] Based on the power distribution under the impedance condition of the hydraulic actuator, the parameters to be determined in the equivalent expression of the load are determined, namely the area ratio of the two chambers of the hydraulic cylinder.

[0021] Based on the load equivalent expression and its parameters, the retracted load of the hydraulic actuator is equivalent to the extended load.

[0022] Furthermore, based on the equivalent post-load trajectory, a method for determining the tight envelope of the hydraulic actuator output characteristic curve to the equivalent post-load trajectory is used to match the hydraulic actuator parameters, specifically including:

[0023] Based on the two convex points of the equivalent load trajectory, calculate the slope of the hydraulic actuator output characteristic curve in the force-velocity square plane, and determine the envelope method of the hydraulic actuator output characteristic curve on the load trajectory under this slope.

[0024] Based on the slope of the hydraulic actuator output characteristic curve, the two convex points of the equivalent load trajectory, and the maximum force and maximum speed points of the equivalent load trajectory, the reference points that tightly enclose the hydraulic actuator output characteristic curve and the load trajectory under different slopes are determined.

[0025] Based on the slope and reference point of the hydraulic actuator output characteristic curve, the envelope method of the hydraulic actuator output characteristic curve to the load trajectory under different slopes is determined, and then the expression of hydraulic actuator parameters is obtained.

[0026] Based on the design requirements of a hydraulic valve-controlled actuator system, a hydraulic actuator parameter matching index is established. The hydraulic actuator parameter matching index includes the maximum power supplied by the hydraulic actuator and the speed square stiffness. The maximum power supplied by the hydraulic actuator is the maximum power consumed by the hydraulic actuator.

[0027] Based on the hydraulic actuator parameter expression and hydraulic actuator parameter matching index, the hydraulic actuator parameters are matched; the hydraulic actuator parameters include the hydraulic cylinder piston area and the servo valve oil passage area.

[0028] Furthermore, in step (3), the hydraulic actuator parameters include the hydraulic cylinder piston area and the servo valve oil passage area.

[0029] Furthermore, based on the velocity-square stiffness of the hydraulic actuator, optimized hydraulic actuator parameters suitable for machining and selection are obtained, specifically including:

[0030] Calculate the velocity square stiffness of the hydraulic actuator based on the matched hydraulic actuator parameters;

[0031] Based on the speed square stiffness of the hydraulic actuator, optimize the piston diameter of the hydraulic cylinder, the piston rod diameter, and the no-load flow rate of the servo valve in the hydraulic actuator.

[0032] Furthermore, in step (4), the hydraulic actuator parameters applicable to processing and selection include the hydraulic cylinder piston diameter, piston rod diameter, and servo valve no-load flow rate.

[0033] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] This invention provides a method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories. First, it determines the equivalent expression of the hydraulic actuator's retracted load to its extended load. Then, based on the parameters to be determined from the equivalent load expression, it determines a method for tightly enveloping the hydraulic actuator's output characteristic curve with the equivalent load trajectory. Finally, it optimizes to obtain hydraulic actuator parameters suitable for manufacturing and selection. Traditional hydraulic actuator parameter matching methods are only applicable to smooth load trajectories. The load matching method provided by this invention can match non-smooth load trajectories, broadening the application scope of existing hydraulic actuator parameter matching methods. Simultaneously, it proposes a matching method for the parameters to be determined from the equivalent load expression, increasing the degree of freedom in hydraulic actuator parameter matching.

[0035] This invention provides a method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories. This method is designed for non-smooth load trajectories, broadening the applicability of existing hydraulic actuator parameter matching methods. Furthermore, it directly integrates four load conditions during the matching process, simplifying the existing hydraulic actuator parameter matching process. At the same time, it provides a hydraulic actuator parameter optimization method for machining and selection, ensuring that the hydraulic actuator used in practice can meet the requirements of the driving load. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. The present invention is also applicable to the corresponding problems in load matching of hydraulic valve-controlled motor / swing cylinder systems. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart illustrating the parameter matching and optimization method for valve-controlled hydraulic actuators for non-smooth load trajectories according to the present invention.

[0038] Figure 2 This is a flowchart illustrating a specific embodiment of the present invention;

[0039] Figure 3 This invention relates to the impedance (overshoot) output characteristics of the hydraulic actuator under extension / retraction conditions.

[0040] Figure 4 This invention describes the non-smooth load trajectory of the hip joint of a certain type of hydraulic quadruped robot under a trot gait at 4 km / h.

[0041] Figure 5 For the present invention Figure 4 The load trajectory of the retracted operating load is equivalent to that of the extended operating load;

[0042] Figure 6 This is the equivalent load trajectory in the force-velocity square plane of the present invention;

[0043] Figure 7 This is a tight envelope diagram of the output characteristic curve of the hydraulic actuator based on the convex point of the load trajectory according to the present invention on the load trajectory;

[0044] Figure 8 This is the envelope diagram of the hydraulic actuator output characteristic curve against the load trajectory when the slope is increased according to the present invention;

[0045] Figure 9 This is the envelope diagram of the hydraulic actuator output characteristic curve against the load trajectory when the slope is reduced according to the present invention;

[0046] Figure 10 This is the envelope of the load trajectory obtained by the hydraulic actuator matched in this invention;

[0047] Figure 11 This is a comparison diagram of the load trajectory envelope before and after the optimization of the hydraulic actuator parameters of the present invention;

[0048] Figure 12 This is a comparison diagram of the envelope of the load trajectory on the force-velocity plane before and after the optimization of the hydraulic actuator parameters of the present invention. Detailed Implementation

[0049] 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 protection scope of the present invention.

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Figure 1 This is a flowchart illustrating the parameter matching and optimization method for valve-controlled hydraulic actuators for non-smooth load trajectories according to the present invention. Figure 2 This is a flowchart illustrating a specific embodiment of the present invention. For example... Figures 1-2 As shown, the parameter matching and optimization method for valve-controlled hydraulic actuators oriented to non-smooth load trajectories of the present invention includes the following steps:

[0052] Step 100: Based on the effective pressure of the hydraulic system, determine the equivalent expression for the hydraulic actuator's retracted load to its extended load. The specific steps are as follows:

[0053] Step 101: Determine the output characteristic expressions of the hydraulic actuator under impedance and overrun conditions based on the effective pressure of the hydraulic system;

[0054] The effective system pressure is defined as the maximum effective pressure p that the hydraulic system can provide to the hydraulic actuator. n Its expression is:

[0055]

[0056] In the formula, n is the area ratio of the two chambers of the hydraulic cylinder, n = A2 / A1, where A1 is the area of ​​the rodless chamber of the hydraulic cylinder and A2 is the area of ​​the rod-side chamber of the hydraulic cylinder; p s p0 is the system pressure, v is the system return back pressure, and p is the speed of the hydraulic cylinder piston. n1 p is the maximum effective pressure when the piston of the hydraulic cylinder moves in the forward direction. n2 This is the maximum effective pressure when the piston of the hydraulic cylinder moves in the reverse direction.

[0057] Based on the effective pressure of the hydraulic system, the output characteristic expression of the hydraulic actuator under various operating conditions is determined as follows:

[0058]

[0059] In the formula, F is the output force of the hydraulic actuator; p1 is the pressure in the rodless chamber of the hydraulic cylinder, p2 is the pressure in the rod chamber of the hydraulic cylinder; Cd A is the flow coefficient at the servo valve throttle orifice. v ρ is the oil passage area of ​​the servo valve; p is the hydraulic oil density; L ρ is the load pressure of the hydraulic actuator; k is the ratio of the load pressure to the effective system pressure.

[0060] Based on the direction of the output force and speed of the hydraulic actuator, the output characteristics of the hydraulic actuator are divided into four operating conditions: resistance extension, resistance retraction, overshoot extension, and overshoot retraction. Figure 3 As shown.

[0061] Step 102: Based on the power properties of the hydraulic actuator and the load, determine the equivalent load expression that equates the retracted load of the hydraulic actuator to the extended load.

[0062] The output force of the hydraulic actuator is equal to the load force. If the direction is not considered, according to equation (2), the impedance extends to the load characteristic point m1(F) of the working condition. L1 ,v L1 ), exceeding the load characteristic point m2 (F) of the extended working condition L2 ,v L2 ), impedance retraction load characteristic point m3 (F) L3 ,v L3 ) and the over-retraction load characteristic point m4(F) L4 ,v L4 The load capacity satisfies:

[0063]

[0064] In the formula, p L1 p indicates the load pressure when the impedance is extended; L2 Indicates the load pressure exceeding the extended working condition; p L3 p represents the load pressure during impedance retraction. L4 k1 represents the load pressure when the load exceeds the retraction condition; k2 represents the ratio of the load pressure to the effective system pressure when the load exceeds the extension condition; k3 represents the ratio of the load pressure to the effective system pressure when the load exceeds the retraction condition; k4 represents the ratio of the load pressure to the effective system pressure when the load exceeds the retraction condition.

[0065] Similarly, the output speed of the hydraulic actuator is equal to the load speed. If direction is not considered, according to equation (2), the load speed at each load characteristic point under each working condition satisfies:

[0066]

[0067] In the resistive extension and resistive retraction conditions, the hydraulic actuator performs positive work; in the over-extension and over-retraction conditions, the hydraulic actuator performs negative work. Furthermore, the ratio of the load pressure corresponding to the maximum output power of the hydraulic actuator in the resistive extension and resistive retraction conditions to the effective system pressure is equal, which can also be analogized to other characteristic points. Therefore, the load in the resistive retraction condition of the hydraulic actuator is equivalent to the load in the resistive extension condition of the hydraulic actuator, and the load in the over-retraction condition of the hydraulic actuator is equivalent to the load in the over-extension condition of the hydraulic actuator. In the equivalence process, let k1 = k3 and k2 = k4. According to equation (3), the equivalent expression for the load force at the load characteristic point is:

[0068]

[0069] Similarly, according to equation (4), the equivalent expression for the load speed at the load characteristic point is:

[0070]

[0071] Based on equations (5) and (6), the equivalent expression for the load power is determined as follows:

[0072]

[0073] Where, N L1 N represents the power at the load characteristic point under impedance extension. L2 To exceed the power characteristic point of the extended operating load, N L3 N represents the power at the load characteristic point under impedance-recovery conditions. L4 The power exceeding the load characteristic point of the retracted operating condition.

[0074] Step 200: Based on the load power distribution, determine the parameters to be calculated in the load equivalent expression, and perform load equivalence. The specific steps are as follows:

[0075] Step 201: Determine the parameters to be determined in the equivalent expression of the load based on the power distribution of the load under the impedance condition of the hydraulic actuator.

[0076] According to equation (7), the parameters to be determined for the load equivalent are, namely, the area ratio n of the two chambers of the hydraulic cylinder. 31 for:

[0077]

[0078] In the formula, N L3 N represents the power at the load characteristic point under impedance-recovery conditions. L31 For N L3 The power equivalent to the impedance extending from the load characteristic point, where p0 represents the system return oil back pressure, p s This indicates the system's oil supply pressure.

[0079] Since the area ratio of the two chambers of a hydraulic cylinder is the ratio of the area of ​​the rod-side chamber to the area of ​​the rodless chamber, its value range satisfies 0 < n ≤ 1. Therefore, according to n 31 The relationship between the value of 1 and the value of 1 can be divided into the following two cases:

[0080] ①If 0 < n 31 If ≤1, then n=n 31 ;

[0081] ②If n 31 If the value is greater than 1, then the area ratio of the two chambers of the hydraulic cylinder is calculated according to the stability criterion of the pressure bar.

[0082] Step 202: Based on the equivalent load expression and its parameters, the retracted load of the hydraulic actuator is equivalent to the extended load; this includes equivalently converting the retracted load of the hydraulic actuator to the extended load of the hydraulic actuator, and converting the over-retracted load of the hydraulic actuator to the over-extended load; thus obtaining the equivalent load trajectory.

[0083] Step 300: Based on the equivalent load trajectory, determine the tight envelope method of the hydraulic actuator output characteristic curve to the equivalent load trajectory, and match the hydraulic actuator parameters. The specific process is as follows:

[0084] Step 301: Based on the two convex points of the equivalent load trajectory, calculate the slope of the hydraulic actuator output characteristic curve in the force-velocity square plane, and determine the envelope method of the hydraulic actuator output characteristic curve on the load trajectory under this slope.

[0085] Based on the equivalent load trajectory (force-velocity plane), the load trajectory on the force-velocity square plane is obtained. Then, based on the two convex points of the equivalent load trajectory on the force-velocity square plane, the slope of the hydraulic actuator output characteristic curve on the force-velocity square plane is calculated, denoted as k. g0 ;

[0086] Based on the slope of the hydraulic actuator output characteristic curve in the force-velocity square plane, determine the value at k. g0 The method of enveloping the output characteristic curve of a hydraulic actuator with respect to the load trajectory under slope; the enveloping method refers to taking the line connecting the two convex points of the equivalent load trajectory as the output characteristic curve of the hydraulic actuator in the force-velocity square plane.

[0087] Step 302: Based on the slope of the hydraulic actuator output characteristic curve, the two convex points of the equivalent load trajectory, and the maximum force point and maximum speed point of the equivalent load trajectory, determine the reference point where the hydraulic actuator output characteristic curve and the load trajectory are closely enveloped under different slopes.

[0088] Based on the equivalent load trajectory, the coordinates of two convex points in the force-velocity square plane, the coordinates of the maximum force point and the maximum velocity point of the load trajectory are obtained. The coordinates of the convex point closest to the maximum force point are denoted as (F...). Lf0 v 2 Lf0 The coordinates of the convex point near the maximum velocity point are (F) Lv0 v 2 Lv0 The coordinates of the point of maximum force are (F) Lfmax v 2 Lfmax The coordinates of the point of maximum velocity are (F) Lvmax v 2 Lvmax );

[0089] In the force-velocity square plane, adjust the slope of the hydraulic actuator output characteristic curve so that from 0 degrees to the slope k g0 Within the corresponding angle, m power mechanism output characteristic curves are uniformly distributed. The slope of the hydraulic actuator output characteristic curve is denoted as k. gi where i = 1, 2, 3, ..., m;

[0090] Based on the coordinates of the two convex points, the maximum velocity point, and the maximum force point in the force-velocity square plane, the slope of the hydraulic actuator output characteristic curve is obtained as k. gi At that time, the coordinates of the reference point (F) where the hydraulic actuator output characteristic curve closely encloses the load trajectory. Li , ):

[0091]

[0092] In the force-velocity square plane, adjust the slope of the hydraulic actuator output characteristic curve so that at a slope k g0 Within the corresponding angle to -90 degrees, l power mechanism output characteristic curves are evenly distributed. The slope of the hydraulic actuator output characteristic curve is denoted as k. gj , where j = 1, 2, 3, ..., l;

[0093] Based on the coordinates of the two convex points, the maximum velocity point, and the maximum force point in the force-velocity square plane, the slope of the hydraulic actuator output characteristic curve is obtained as k. gj At that time, the coordinates of the reference point where the output characteristic curve of the hydraulic actuator closely encloses the load trajectory are:

[0094]

[0095] Step 303: Based on the slope of the hydraulic actuator output characteristic curve and its reference point, determine the envelope method of the hydraulic actuator output characteristic curve to the load trajectory under different slopes, and derive the expression of the hydraulic actuator parameters.

[0096] Based on the slope of the hydraulic actuator output characteristic curve and its corresponding reference point coordinates, determine the hydraulic actuator output characteristic curve under different slopes, and complete the tight envelope of the hydraulic actuator output characteristic curve to the load trajectory under different slopes.

[0097] In the force-velocity square plane, based on the slope of the hydraulic actuator output characteristic curve and its corresponding reference point, the expression for the hydraulic actuator parameters is derived as follows:

[0098] Based on the selected r hydraulic actuator output characteristic curves with different slopes, the slope is represented by k. gr Where r = 1, 2, 3, ..., m + l + 1 (slope greater than k) g0 There are m, less than k g0 There are l, which equals k. g0 There is one, meaning the maximum value of r is m+l+1). The corresponding hydraulic actuator parameters are calculated as follows:

[0099]

[0100] Among them, A 1r This represents the area of ​​the rodless chamber of the hydraulic cylinder corresponding to the output characteristic curve of the hydraulic actuator with different slopes (F). Lr , A represents the coordinates of the reference point corresponding to the output characteristic curve of the hydraulic actuator with different slopes for the r-th time. vr P represents the servo valve oil passage area corresponding to the output characteristic curve of the hydraulic actuator with different slopes for the r-th time. n This indicates the effective pressure of the system.

[0101] Step 304: Based on the design requirements of the valve-controlled hydraulic actuator system, establish hydraulic actuator parameter matching indicators;

[0102] To balance the weight and control performance of the hydraulic actuator, a parameter matching index J for the hydraulic actuator is established. h for:

[0103]

[0104] In the formula, N p The maximum power supplied to the hydraulic actuator is proportional to the weight of the hydraulic actuator. Let α be the speed square stiffness of the hydraulic actuator, which is positively correlated with the control energy of the hydraulic actuator; α is a weighting coefficient related to the maximum power supplied by the hydraulic actuator; β is a weighting coefficient related to the speed square stiffness of the hydraulic actuator; and satisfy α+β=1. By adjusting the values ​​of α and β, different hydraulic actuator parameters can be obtained.

[0105] The expression for the maximum power supplied by the hydraulic actuator is:

[0106] N p =P s A1max(v eL (13)

[0107] In the formula, v eL Equivalent post-load speed;

[0108] The expression for the velocity-square stiffness of a hydraulic actuator is:

[0109]

[0110] Step 305: Match the hydraulic drive parameters based on the hydraulic drive parameter expression and hydraulic drive parameter matching index;

[0111] Based on the selected r hydraulic actuator output characteristic curves with different slopes, calculate the corresponding hydraulic actuator parameters, and quantize the maximum supply power and speed square stiffness of the r hydraulic actuators to 0-100 respectively.

[0112] The maximum supply power and speed square stiffness of the quantified hydraulic actuator are added together. Based on the maximum value of the sum of the two quantified indices, the hydraulic actuator parameters are matched and obtained, denoted as A. 1opt and A vopt .

[0113] Step 400: Based on the velocity-square stiffness of the hydraulic actuator, optimize and obtain hydraulic actuator parameters suitable for machining and selection. The specific process is as follows:

[0114] Step 401: Calculate the velocity square stiffness of the hydraulic actuator based on the hydraulic actuator parameters and equation (14):

[0115]

[0116] Step 402: Optimize the hydraulic cylinder piston diameter, piston rod diameter, and servo valve no-load flow rate in the hydraulic actuator based on the speed square stiffness of the hydraulic actuator;

[0117] Calculate the piston diameter D of the hydraulic cylinder based on the area of ​​the rodless chamber of the hydraulic cylinder. opt for:

[0118]

[0119] Based on the calculation results of equation (16), the hydraulic cylinder piston diameter is optimized by rounding upwards, and the piston rod diameter is optimized by rounding downwards, resulting in the optimized hydraulic cylinder piston diameter D. optR and piston rod diameter d optR They are respectively:

[0120] D optR =roundup(D opt (17)

[0121]

[0122] In the formula, roundup is the round-up function and rounddown is the round-down function.

[0123] Calculate the optimized rodless chamber area A of the hydraulic cylinder based on the optimized piston diameter. 1optR for:

[0124]

[0125] Based on the optimized piston rod diameter and the area of ​​the rodless chamber of the hydraulic cylinder, calculate the optimized ratio n of the two chamber areas of the hydraulic cylinder. R for:

[0126]

[0127] Based on the principle that the speed square stiffness of the hydraulic actuator is equal before and after optimization, the oil passage area A of the servo valve is optimized. voptR for:

[0128]

[0129] Based on the optimized oil flow area of ​​the servo valve, calculate the no-load flow rate of the servo valve, and select a suitable servo valve from the market.

[0130] Based on the optimized oil passage area of ​​the servo valve, the no-load flow rate Q0 of the servo valve is calculated as follows:

[0131]

[0132] In the formula, p c The test system pressure corresponds to the no-load flow rate of the servo valve.

[0133] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0134] like Figure 4The image shows the non-smooth load trajectory of the hip joint of a certain type of hydraulic quadruped robot under a trot gait at 4 km / h. This invention uses this as the load trajectory in an embodiment. System pressure p s =21MPa, return oil back pressure p0=0.5MPa, servo valve throttle port flow coefficient C d =0.69, hydraulic oil density ρ = 890 kg / m³ 3 The test system pressure p corresponding to the no-load flow rate of the servo valve c =21MPa.

[0135] According to the flowchart of a specific implementation example of the present invention, the embodiment includes the following steps:

[0136] Step 100: Based on the effective pressure of the hydraulic system, determine the equivalent expression for the hydraulic actuator retracted load to the extended load.

[0137] Step 101: Determine the output characteristic expressions of the hydraulic actuator under impedance and overrun conditions based on the effective pressure of the hydraulic system;

[0138] The effective system pressure is:

[0139]

[0140] The output characteristic expressions for the hydraulic actuator under impedance and overrun conditions are as follows:

[0141]

[0142] Step 102: Based on the power properties of the hydraulic actuator and the load, determine the equivalent load expression that equates the load corresponding to the retracted hydraulic actuator condition to the extended hydraulic actuator condition.

[0143] The equivalent expression for load capacity is:

[0144]

[0145] The equivalent expression for load speed is:

[0146]

[0147] The equivalent expression for load power is:

[0148]

[0149] Step 200: Based on the load power distribution, determine the parameters to be determined in the load equivalent expression, and perform load equivalence.

[0150] Step 201: Determine the parameters to be determined in the equivalent expression of the load based on the power distribution of the load corresponding to the impedance condition of the hydraulic actuator.

[0151] The maximum power point of the load under the hydraulic actuator's retracted load condition is equivalent to that under the retracted load condition, and the equivalent power is equal to the maximum power point of the load under the retracted load condition. Based on... Figure 4 The load trajectory characteristics shown can be used to obtain N. L3 =0.8117kW, N L31 =2.5397kW.

[0152] The parameters to be determined for the load equivalent are:

[0153]

[0154] Since 0 < n 31 ≤1, therefore we take n = n 31 =0.48.

[0155] The effective system pressure of the valve-controlled hydraulic actuator is determined as follows:

[0156]

[0157] Step 202: Based on the load equivalent expression and its parameters, the load of the hydraulic actuator in retraction mode is equivalent to the load in extension mode, such as... Figure 5 As shown, the equivalent load trajectory is mapped from the force-velocity plane to the force-velocity square plane, as follows: Figure 6 As shown.

[0158] Step 300: Based on the equivalent load trajectory, determine the tight envelope method of the hydraulic actuator output characteristic curve to the equivalent load trajectory, and match the hydraulic actuator parameters.

[0159] Step 301: Based on the two convex points of the equivalent load trajectory, calculate the slope of the hydraulic actuator output characteristic curve in the force-velocity square plane, and determine the envelope method of the hydraulic actuator output characteristic curve on the load trajectory under this slope.

[0160] The two convex points of the equivalent load trajectory in the force-velocity square plane are determined to be (642.899, 5.51341) and (5977.13, 0.168071).

[0161] Based on the two convex points of the equivalent load trajectory in the force-velocity square plane, the slope k of the hydraulic actuator output characteristic curve in the force-velocity square plane is calculated. g0 = -0.9979, obtaining the envelope of the hydraulic actuator output characteristic curve with respect to the load trajectory in the force-velocity square plane, such as Figure 7 As shown.

[0162] Step 302: Based on the slope of the hydraulic actuator output characteristic curve, the two convex points of the equivalent load trajectory, and the maximum force point and maximum speed point of the equivalent load trajectory, determine the reference point where the hydraulic actuator output characteristic curve and the load trajectory are closely enveloped under different slopes.

[0163] Based on the equivalent load trajectory, the coordinates of two convex points in the force-velocity square plane, the coordinates of the maximum force point and the maximum velocity point of the load trajectory are obtained. The coordinates of the convex point close to the maximum force point are (5977.13, 0.168071), the coordinates of the convex point close to the maximum velocity point are (642.899, 5.51341), the coordinates of the maximum force point are (5979.84, 0.165396), and the coordinates of the maximum velocity point are (623.162, 5.58006).

[0164] In the force-velocity square plane, adjust the slope of the hydraulic actuator output characteristic curve so that from 0 degrees to the slope k g0 Within the corresponding angle, 15 power mechanism output characteristic curves are evenly distributed. The slope of the hydraulic actuator output characteristic curve is denoted as k. gi Where i = 1, 2, 3, ..., 15, the slopes of the adjusted 15 hydraulic actuator output characteristic curves are as follows: k g1 =-0.0021, k g2 =-0.0545, k g3 =-0.1072, k g4 =-0.1604, k g5 =-0.2146, k g6 =-0.2701, k g7 =-0.3271, k g8 =-0.3861, k g9 =-0.4475, k g10 =-0.5119, k g11 =-0.5798, k g12 =-0.6519, k g13 =-0.7292, k g14 =-0.8126, k g15 = -0.9035;

[0165] Based on the coordinates of the two convex points, the maximum velocity point, and the maximum force point in the force-velocity square plane, the slope of the hydraulic actuator output characteristic curve is obtained as k. giAt that time, the coordinates of the reference points that closely enclose the output characteristic curve of the hydraulic actuator with the load trajectory are: (623.162, 5.5801), (624.4778, 5.5756), (625.7936, 5.5712), (627.1094, 5.5667), (628.4252, 5.5623), (629.7410, 5.5578), (631.068, 5.5801). 5534), (632.3726,5.5490), (633.6884,5.5445), (635.0042,5.5401), (636.3200,5.5356), (637.6358,5.5312), (638.9516,5.5267), (640.2674,5.5223), (641.5832,5.5179);

[0166] In the force-velocity square plane, adjust the slope of the hydraulic actuator output characteristic curve so that at a slope k g0 Within the corresponding angle to -90 degrees, 14 power mechanism output characteristic curves are evenly distributed. The slope of the hydraulic actuator output characteristic curve is denoted as k. gj (For ease of representation, k will be...) g0 Let it be k g16 After adjustment, it is less than k g0 The first slope is denoted as k. g17 ), where j = 17, 18, 19, ..., 30, the slopes of the adjusted 14 hydraulic actuator output characteristic curves are respectively: k g17 =-1.1143, k g18 =-1.2391, k g19 =-1.3811, k g20 =-1.5452, k g21 =-1.7383, k g22 =-1.9701, k g23 =-2.2552, k g24 =-2.6167, k g25 =-3.0930, k g26 =-3.7535, k g27 =-4.7373, k g28 =-6.3705, k g29 =-9.6395, k g30 = -19.5769;

[0167] Based on the coordinates of the two convex points, the maximum velocity point, and the maximum force point in the force-velocity square plane, the slope of the hydraulic actuator output characteristic curve is obtained as k. gjAt that time, the coordinates of the reference points where the hydraulic actuator output characteristic curve and the load trajectory are closely enveloped are: (5977.3236, 0.1679), (5977.5171, 0.1677), (5977.7107, 0.1675), (5977.9042, 0.1673), (5978.0979, 0.1671), (5978.2914, 0.1669), (59 78.4850,0.1667), (5978.6786,0.1665), (5978.8721,0.1664), (5979.0657,0.1662), (5979.2593,0.1660), (5979.4529,0.1658), (5979.6464,0.1656), (5979.8400,0.1654);

[0168] Step 303: Based on the slope of the hydraulic actuator output characteristic curve and its reference point, determine the envelope method of the hydraulic actuator output characteristic curve to the load trajectory under different slopes, and derive the expression of the hydraulic actuator parameters.

[0169] Based on the slope of the hydraulic actuator output characteristic curve and its corresponding reference point coordinates, the hydraulic actuator output characteristic curves under different slopes are determined, and a tight envelope of the load trajectory by the hydraulic actuator output characteristic curves under different slopes is completed, such as... Figure 8 and Figure 9 As shown;

[0170] In the force-velocity square plane, based on the slope of the hydraulic actuator output characteristic curve and its corresponding reference point, derive the expressions for the hydraulic actuator parameters, A1, A... v The unit is m 2 :

[0171]

[0172] Step 304: Based on the design requirements of the valve-controlled hydraulic actuator system, establish hydraulic actuator parameter matching indicators;

[0173] According to equation (11), calculate the maximum supply power and speed square stiffness of the hydraulic actuators for r different hydraulic actuators, with units of W and N·s, respectively. 2 / m 2 :

[0174]

[0175] The maximum supply power and speed square stiffness of different hydraulic drives are quantized to the range of 0 to 100:

[0176]

[0177] Step 305: Match the hydraulic drive parameters based on the hydraulic drive parameter expression and hydraulic drive parameter matching index;

[0178] α is a weighting coefficient related to the maximum power supplied by the hydraulic actuator; β is a weighting coefficient related to the speed square stiffness of the hydraulic actuator; and α+β=1, then by adjusting the values ​​of α and β, different hydraulic actuator parameters can be matched; in this embodiment, α=0.501 and β=0.499 are taken, and combined with equation (12) to obtain the matching index values ​​of different hydraulic actuator parameters:

[0179]

[0180] Take the maximum value among the hydraulic actuator parameter matching index values ​​in equation (33), and the corresponding hydraulic actuator parameters are the hydraulic actuator parameters that meet the requirements of the valve-controlled hydraulic system:

[0181]

[0182] The envelope of the load trajectory corresponding to the hydraulic actuator in equation (34) is as follows: Figure 10 As shown.

[0183] Step 400: Based on the speed square stiffness of the hydraulic actuator, optimize to obtain hydraulic actuator parameters suitable for machining and selection.

[0184] Step 401: Calculate the velocity square stiffness of the hydraulic actuator based on its parameters:

[0185]

[0186] Step 402: Optimize the piston diameter and piston rod diameter of the hydraulic cylinder based on the area of ​​the rodless chamber of the hydraulic cylinder;

[0187] Based on the area of ​​the rodless chamber of the hydraulic cylinder, the piston diameter of the hydraulic cylinder is calculated as follows:

[0188]

[0189] The hydraulic cylinder piston diameter is optimized by rounding upwards, and the piston rod diameter is optimized by rounding downwards, resulting in the following optimized hydraulic cylinder piston and piston rod diameters:

[0190] D optR =roundup(D opt )=21mm (37)

[0191]

[0192] Step 403: Optimize the oil passage area of ​​the servo valve based on the optimized hydraulic cylinder piston diameter;

[0193] The optimized area of ​​the rodless chamber of the hydraulic cylinder is calculated as follows:

[0194]

[0195] The optimized ratio of the two chamber areas of the hydraulic cylinder is calculated as follows:

[0196]

[0197] Based on the fact that the velocity square stiffness of the hydraulic actuator is equal before and after optimization, the optimized oil passage area of ​​the servo valve is:

[0198]

[0199] Step 404: Calculate the no-load flow rate of the servo valve based on the optimized oil flow area of ​​the servo valve, and select a suitable servo valve on the market.

[0200] The servo valve's no-load flow rate is calculated as follows:

[0201]

[0202] Based on the matched hydraulic actuator parameters (Equation 34) and the optimized hydraulic actuator parameters (Equations 39 and 41), the following is obtained: Figure 11 The figure shown is a comparison of the load trajectory envelope before and after the optimization of the hydraulic actuator parameters of the present invention. Figure 12 The figure shown is a comparison of the envelope of the load trajectory on the force-velocity plane before and after the optimization of the hydraulic actuator parameters of the present invention.

[0203] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories, characterized in that: (1) Based on the effective pressure of the hydraulic system, determine the equivalent expression of the hydraulic actuator retracted load to the extended load, including: the equivalent expression of the load force and load speed of the hydraulic actuator resistive retracted load to the resistive extended load, and the equivalent expression of the load force and load speed of the hydraulic actuator over-retracted load to the over-extended load. (2) Based on the load power distribution, determine the area ratio of the two chambers of the hydraulic actuator hydraulic cylinder in the load equivalent expression, and convert the retracted working condition load of the hydraulic actuator into the extended working condition load to obtain the equivalent load trajectory. (3) Based on the equivalent post-load trajectory, determine the tight envelope method of the hydraulic actuator output characteristic curve to the equivalent post-load trajectory, and match the hydraulic actuator parameters; the hydraulic actuator output characteristic curve is divided into the relationship between force and velocity in the force-velocity (Fv) plane, and the relationship between force and velocity square (Fv) plane. 2 The relationship between force and the square of velocity in a plane; (4) Based on the speed square stiffness of the hydraulic actuator, optimize the hydraulic actuator parameters suitable for processing and selection; the speed square stiffness is the reciprocal of the slope of the output characteristic curve of the hydraulic actuator in the force-speed square plane.

2. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories according to claim 1, characterized in that, In step (1), the effective pressure of the hydraulic system is the maximum effective pressure that the hydraulic system can provide to the hydraulic actuator.

3. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories according to claim 1, characterized in that, The process of determining the equivalent expression for the hydraulic actuator's retracted load to its extended load based on the effective pressure of the hydraulic system specifically includes: Based on the effective pressure of the hydraulic system, determine the output characteristic expressions of the hydraulic actuator under impedance and overrun conditions; Based on the power properties of the hydraulic actuator and the load, determine the equivalent load expression for the hydraulic actuator retracted load to the hydraulic actuator extended load.

4. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories according to claim 1, characterized in that, The step of determining the parameters to be calculated in the load equivalent expression based on the load power distribution and performing load equivalence specifically includes: Based on the power distribution under the impedance condition of the hydraulic actuator, the parameters to be determined in the equivalent expression of the load are determined, namely the area ratio of the two chambers of the hydraulic cylinder. Based on the equivalent load expression and the obtained ratio of the two chamber areas of the hydraulic cylinder, the retracted load of the hydraulic actuator is equivalent to the extended load.

5. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories as described in claim 1, characterized in that, The method for determining the tight envelope of the hydraulic actuator output characteristic curve to the equivalent load trajectory based on the equivalent load trajectory, and matching the hydraulic actuator parameters, specifically includes: Based on the two convex points of the equivalent load trajectory, calculate the slope of the hydraulic actuator output characteristic curve in the force-velocity square plane, and determine the envelope method of the hydraulic actuator output characteristic curve on the load trajectory under this slope. Based on the slope of the hydraulic actuator output characteristic curve, the two convex points of the equivalent load trajectory, and the maximum force and maximum speed points of the equivalent load trajectory, the reference points that tightly enclose the hydraulic actuator output characteristic curve and the load trajectory under different slopes are determined. Based on the slope and reference point of the hydraulic actuator output characteristic curve, the envelope method of the hydraulic actuator output characteristic curve to the load trajectory under different slopes is determined, and then the expression of hydraulic actuator parameters is obtained. Based on the design requirements of a hydraulic valve-controlled actuator system, a hydraulic actuator parameter matching index is established. The hydraulic actuator parameter matching index includes the maximum power supplied by the hydraulic actuator and the speed square stiffness. The maximum power supplied by the hydraulic actuator is the maximum power consumed by the hydraulic actuator. Based on the hydraulic actuator parameter expression and hydraulic actuator parameter matching index, the hydraulic actuator parameters are matched; the hydraulic actuator parameters include the hydraulic cylinder piston area and the servo valve oil passage area.

6. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories according to claim 1, characterized in that, In step (3), the hydraulic drive parameters include the hydraulic cylinder piston area and the servo valve oil passage area.

7. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories as described in claim 1, characterized in that, The optimization of hydraulic actuator parameters based on the velocity-square stiffness of the hydraulic actuator to obtain parameters suitable for machining and selection specifically includes: Calculate the velocity square stiffness of the hydraulic actuator based on the hydraulic actuator parameters; Based on the speed square stiffness of the hydraulic actuator, optimize the piston diameter of the hydraulic cylinder, the piston rod diameter, and the no-load flow rate of the servo valve in the hydraulic actuator.

8. The method for parameter matching and optimization of valve-controlled hydraulic actuators for non-smooth load trajectories according to claim 1, characterized in that, In step (4), the hydraulic actuator parameters applicable to processing and selection include the hydraulic cylinder piston diameter, piston rod diameter, and servo valve no-load flow rate.

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