阅读说明：本技术 适应发动机变推力工况的伺服机构液动机能源匹配方法 (Servo mechanism hydraulic motor energy matching method adapting to variable thrust working condition of engine ) 是由 肖雪 刘洪� 兰天 陈克勤 赵迎鑫 薛婵 麻翠娟 吴泽旭 刘会祥 谢海丰 于 2021-08-06 设计创作，主要内容包括：一种适应发动机变推力工况的伺服机构液动机能源匹配方法,步骤一,获取伺服机构持续摆动速度ω、伺服机构摇摆力臂R、伺服机构能源参数和结构参数；步骤二,根据步骤一获取的伺服机构持续摆动速度ω、伺服机构摇摆力臂R、伺服机构能源参数和结构参数,设计并选定液压泵的排量V′-(p)；步骤三,考虑液动机输出功率和液压泵输入功率的功率平衡关系,设计并选定液动机的排量V′-(m)；步骤四,根据选定的液压泵排量V′-(p)和液动机排量V′-(m),对引流煤油压力变化下的液动机恒速功能进行验证,完成匹配。本发明可根据引流煤油压力的变化范围,快速确定液压泵、液动机排量的合理比值,实现引流能源功率与液压能源功率匹配,并通过液动机进油口处的恒速阀保持动力组件转速恒定。(A servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of an engine comprises the following steps of obtaining the continuous swing speed omega of a servo mechanism, the swing force arm R of the servo mechanism, the energy parameters and the structural parameters of the servo mechanism; step two, designing and selecting the displacement V 'of the hydraulic pump according to the continuous swing speed omega of the servo mechanism, the swing moment arm R of the servo mechanism, the energy parameter and the structural parameter of the servo mechanism, which are obtained in the step one' p (ii) a Step three, considering the power balance relation between the output power of the hydraulic engine and the input power of the hydraulic pump, designing and selecting the displacement V 'of the hydraulic engine' m (ii) a Step four, according to the selected hydraulic pump displacement V' p And hydraulic motor displacement V' m And verifying the constant-speed function of the hydraulic motor under the condition of changing the pressure of the drainage kerosene to finish matching. The invention can be used according to the followingThe change range of the flow kerosene pressure quickly determines the reasonable ratio of the discharge capacities of the hydraulic pump and the hydraulic motor, realizes the matching of the drainage energy power and the hydraulic energy power, and keeps the constant rotating speed of the power assembly through a constant speed valve at the oil inlet of the hydraulic motor.)

1. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine is characterized by comprising the following steps:

acquiring a continuous swing speed omega of a servo mechanism, a swing force arm R of the servo mechanism, energy parameters and structural parameters of the servo mechanism; the energy parameters comprise the pressure p of the drainage kerosene_mDrainage oil return pressure p_m0Rated system operating pressure p_pHydraulic pump return pressure p_p0Pressure drop delta p at fixed orifice of constant speed valve_vHydraulic motor comprehensive efficiency eta_mHydraulic motor volumetric efficiency eta_mvHydraulic pump comprehensive efficiency eta_pHydraulic pump volumetric efficiency eta_pvThe working speed n of the hydraulic pump_pAnd the operating speed n of the hydraulic motor_m(ii) a Structural parameters includeActuator piston area A; the constant speed valve is connected in series at an oil inlet of the hydraulic motor;

step two, calculating the displacement V of the hydraulic pump according to the continuous swing speed omega of the servo mechanism, the swing force arm R of the servo mechanism, the energy parameter and the structural parameter of the servo mechanism, which are obtained in the step one_pIs selected from the design range, and one hydraulic pump displacement value V 'meeting the requirement is selected from the design range'_p；

Displacement V of hydraulic pump_pIs designed within a range of

Step three, the hydraulic motor and the hydraulic pump adopt a coaxial design, namely n_m＝n_pConsidering the power balance relation between the output power of the hydraulic engine and the input power of the hydraulic pump, the displacement V 'of the hydraulic pump is selected according to the step two'_pTo calculate the displacement V of the hydraulic motor_mThe design range of (1), and selecting a hydraulic engine displacement value V 'meeting the requirement from the design range'_m；

Hydraulic motor displacement V_mIs designed within a range of

Step four, selecting the displacement V 'of the hydraulic pump according to the step two and the step three'_pAnd hydraulic motor displacement V'_mAnd verifying the constant speed function under the change of the drainage pressure, and completing the energy source matching of the hydraulic motor of the servo mechanism after the verification is passed.

2. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 1, characterized in that: the constant-speed valve comprises a constant-difference pressure-reducing valve and a fixed throttling hole, the fixed throttling hole is arranged at an oil outlet of the constant-difference pressure-reducing valve, and a valve core opening x of the constant-speed valve_vWill follow the pressure p of the drained kerosene_mAnd the pressure difference before and after the fixed orifice is kept constant through changing, so that the flow rate of the oil liquid is constant.

3. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 2, characterized in that: in step four, the selected hydraulic pump displacement V 'is verified using the method'_pAnd hydraulic motor displacement V'_m：

S1, according to the selected hydraulic pump displacement V'_pAnd hydraulic motor displacement V'_mCalculating the cross-sectional area A of the fixed orifice of the constant-speed valve₀And the pressure drop Δ p over the hydraulic motor_m；

S2, utilizing pressure drop Δ p on hydraulic motor_mPressure drop delta p at fixed orifice of constant speed valve_vAnd the pressure p of the drainage kerosene_mCalculating the pressure drop deltap over the spool of the constant speed valve_sA range of (d);

s3, fixing the orifice according to the cross-sectional area A of the constant speed valve₀And pressure drop Δ p across the spool of the constant speed valve_sCalculating the constant speed valve spool opening x_v；

S4, if the calculated constant speed valve core opening x_vWithin a reasonable range, then verify passed, otherwise reselect the hydraulic pump displacement V'_pAnd hydraulic motor displacement V'_m。

4. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 3, characterized in that: in step S4, the constant speed valve spool opening x_vThe reasonable range is 0.2-1.5 mm.

5. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 3, characterized in that: in step S1, the pressure drop Δ p across the hydraulic motor is calculated using the following formula_m；

In the formula, p_v2The pressure at the upper end of the valve core of the constant-speed valve.

6. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 5, characterized in that: in the step S1, the cross-sectional area a of the constant speed valve fixed orifice₀Satisfies the following conditions:

wherein, C_d0To fix the flow coefficient of the orifice, ρ is the density of the tapped kerosene.

7. The servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 3, characterized in that: in step S3, the pressure drop Δ p across the spool of the constant speed valve is calculated using the following equation_sThe range of (A):

Δp_s＝p_m-p_m0-Δp_v-Δp_m。

8. the servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine as claimed in claim 3, characterized in that: in step S3, the constant speed valve spool opening x is calculated using the following formula_v；

Wherein, C_svIs the flow coefficient at the valve core of the constant-speed valve, W_svIs a fixed orifice area gradient.

Technical Field

The invention belongs to the field of rocket servo mechanism design, and relates to a servo mechanism hydraulic motor energy matching method adapting to a variable thrust working condition of a liquid oxygen kerosene engine.

Background

At present, liquid oxygen kerosene rockets at home and abroad adopt an engine variable thrust adjusting technology to reduce flying dynamic pressure and overload. This technique results in significant changes in kerosene pressure after the pump, which places adaptive service requirements on the associated servomechanism. For a servo mechanism scheme of a high-pressure kerosene drive actuator of a direct drainage engine, the kerosene pressure changes in a large range, so that the oil supply pressure of a servo valve deviates from the rated design working condition, and the control performance is influenced.

Disclosure of Invention

The technical problem solved by the invention is as follows: the method overcomes the defects of the prior art, provides the servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine, ensures the oil supply pressure of the servo valve to be within the rated design working condition when the thrust of the liquid oxygen kerosene engine is adjusted in a large range, and realizes the stable control of the rotating speed of the servo power assembly and the reasonable matching of the drainage energy power and the hydraulic energy power of the servo mechanism.

The technical scheme of the invention is as follows:

the servo mechanism hydraulic motor energy matching method adapting to the variable thrust working condition of the engine comprises the following steps:

acquiring a continuous swing speed omega of a servo mechanism, a swing force arm R of the servo mechanism, energy parameters and structural parameters of the servo mechanism; the energy parameters comprise the pressure p of the drainage kerosene_mDrainage oil return pressure p_m0Rated system operating pressure p_pHydraulic pump return pressure p_p0Pressure drop delta p at fixed orifice of constant speed valve_vHydraulic motor comprehensive efficiency eta_mHydraulic motor volumetric efficiency eta_mvHydraulic pump comprehensive efficiency eta_pHydraulic pump volumetric efficiency eta_pvThe working speed n of the hydraulic pump_pAnd the operating speed n of the hydraulic motor_m(ii) a The structural parameters include the actuator piston area A; the constant speed valve is connected in series at an oil inlet of the hydraulic motor;

step two, calculating the displacement V of the hydraulic pump according to the continuous swing speed omega of the servo mechanism, the swing force arm R of the servo mechanism, the energy parameter and the structural parameter of the servo mechanism, which are obtained in the step one_pSelecting a hydraulic pump displacement value V satisfying the requirement from the design range_p′；

Displacement V of hydraulic pump_pIs designed within a range of

Step three, the hydraulic motor and the hydraulic pump adopt a coaxial design, namely n_m＝n_pConsidering the power balance relation between the output power of the hydraulic engine and the input power of the hydraulic pump, the displacement V 'of the hydraulic pump is selected according to the step two'_pTo calculate the displacement V of the hydraulic motor_mThe design range of (1), and selecting a hydraulic engine displacement value V 'meeting the requirement from the design range'_m；

Hydraulic motor displacement V_mIs designed within a range of

Step four, selecting the displacement V 'of the hydraulic pump according to the step two and the step three'_pAnd hydraulic motor displacement V'_mAnd verifying the constant speed function under the change of the drainage pressure, and completing the energy source matching of the hydraulic motor of the servo mechanism after the verification is passed.

The constant-speed valve comprises a constant-difference pressure-reducing valve and a fixed throttling hole, the fixed throttling hole is arranged at an oil outlet of the constant-difference pressure-reducing valve, and a valve core opening x of the constant-speed valve_vWill follow the pressure p of the drained kerosene_mAnd the pressure difference before and after the fixed orifice is kept constant through changing, so that the flow rate of the oil liquid is constant.

In step four, the selected hydraulic pump displacement V 'is verified using the method'_pAnd hydraulic motor displacement V'_m：

S1, according to the selected hydraulic pump displacement V'_pAnd hydraulic motor displacement V'_mCalculating the cross-sectional area A of the fixed orifice of the constant-speed valve₀And the pressure drop Δ p over the hydraulic motor_m；

S2, utilizing pressure drop Δ p on hydraulic motor_mPressure drop delta p at fixed orifice of constant speed valve_vAnd the pressure p of the drainage kerosene_mCalculating the pressure drop deltap over the spool of the constant speed valve_sA range of (d);

s3, fixing the orifice according to the cross-sectional area A of the constant speed valve₀And pressure drop Δ p across the spool of the constant speed valve_sCalculating the constant speed valve spool opening x_v；

S4, if the calculated constant speed valve core opening x_vWithin a reasonable range, then verify passed, otherwise reselect the hydraulic pump displacement V'_pAnd hydraulic motor displacement V'_m。

In step S4, the constant speed valve spool opening x_vThe reasonable range is 0.2-1.5 mm.

In step S1, the pressure drop Δ p across the hydraulic motor is calculated using the following formula_m；

In the formula, p_v2The pressure at the upper end of the valve core of the constant-speed valve.

The step S1Middle constant speed valve fixed orifice cross-sectional area A₀Satisfies the following conditions:

wherein, C_d0To fix the flow coefficient of the orifice, ρ is the density of the tapped kerosene.

In step S3, the pressure drop Δ p across the spool of the constant speed valve is calculated using the following equation_sThe range of (A):

Δp_s＝p_m-p_m0-Δp_v-Δp_m。

in step S3, the constant speed valve spool opening x is calculated using the following formula_v；

Wherein, C_svIs the flow coefficient at the valve core of the constant-speed valve, W_svIs a fixed orifice area gradient.

Compared with the prior art, the invention has the beneficial effects that:

(1) the method is simple, efficient and easy to implement, and can quickly determine the reasonable ratio of the displacement of the hydraulic pump and the hydraulic motor of the servo mechanism according to the variation range of the pressure of the drainage kerosene;

(2) by adopting the design method, the reasonable matching of the drainage energy power and the system hydraulic energy power under the large-range variable thrust regulation of the liquid oxygen kerosene engine can be ensured, and the margin is provided, so that the oil supply pressure of the servo valve is ensured to be within the rated design working condition, the constant rotating speed of the servo power assembly is realized, and the self-adaptive control of the servo mechanism is realized.

Drawings

FIG. 1 is a schematic diagram of the operation of a hydraulic motor drainage type servo mechanism;

FIG. 2 is a simplified schematic diagram of a servo energy apparatus;

fig. 3 is a flow chart of the energy matching method of the present invention.

Detailed Description

The invention is further elucidated with reference to the drawing.

The invention provides a servo mechanism hydraulic motor energy matching method by adopting a hydraulic motor drainage engine high-pressure kerosene scheme so as to adapt to the variable thrust working condition of an engine.

The invention adopts a constant-speed hydraulic motor drainage scheme, reasonably matches the power of drainage energy and system hydraulic energy, quickly determines the displacement of a hydraulic pump and the hydraulic motor, and keeps the rotating speed of a power assembly constant through a constant-speed valve so as to adapt to the large-range change of the kerosene pressure after the pump caused by the thrust adjustment of an engine.

The working principle diagram of the hydraulic motor flow-guiding type servo mechanism is shown in figure 1. High-pressure kerosene enters the hydraulic motor 1 through a hose, a drainage high-pressure kerosene filter 6 and a constant-speed valve 5 after a primary pump of the engine, the hydraulic motor 1 is driven to rotate, and the constant-speed valve 5 maintains the constant output of the rotating speed of the hydraulic motor 1. The hydraulic motor 1 drives the motor 2 to rotate through the overrunning clutch 4, and then drives the hydraulic pump 3 to rotate at a high speed, so that hydraulic energy required by the actuator is generated. The kerosene which has done work is discharged from the oil outlet of the hydraulic motor and returns to the front of the engine pump through the return oil low-pressure kerosene oil filter 7 and the hose.

Under the thrust adjusting working condition of the liquid oxygen kerosene engine, the kerosene pressure after the primary pump is obviously reduced, and for a liquid engine running constantly, the input power of the liquid oxygen kerosene engine is also reduced. In order to maintain the stable operation of the servo mechanism energy system under the minimum throttling condition, the matching relationship between the input energy and the system hydraulic energy power needs to be adjusted. A simplified servo energy device model is shown in fig. 2. During flight, the motor is not operated, and is omitted here.

Acquiring a continuous swing speed omega of a servo mechanism, a swing force arm R of the servo mechanism, energy parameters and structural parameters of the servo mechanism; wherein the energy parameter comprises the pressure p of the drainage kerosene_mDrainage oil return pressure p_m0Rated system operating pressure p_pHydraulic pump return pressure p_p0Pressure drop delta p at fixed orifice of constant speed valve_vHydraulic motor comprehensive efficiency eta_mHydraulic motor volumetric efficiency eta_mvHydraulic pump comprehensive efficiency eta_pHydraulic pump volumetric efficiency eta_pvThe working speed n of the hydraulic pump_pAnd the operating speed n of the hydraulic motor_m(ii) a The structural parameters include the actuator piston area a.

Output power P of hydraulic motor_mWith the pressure p of kerosene drained by hydraulic motor_mThe relationship (c) is shown in the formula (1).

Throttling operation of engine, guiding kerosene pressure p_mWill decrease, therefore, the output power P of the hydraulic motor_mWill be reduced.

The power of the hydraulic energy source is determined by the power of the hydraulic pump. Input power P of hydraulic pump of servo mechanism_pDetermined by equation (2).

Considering the power balancing relationship and preserving the design margin is:

P_m≥P_p (3)

the hydraulic motor and the hydraulic pump are designed coaxially, so that the hydraulic motor and the hydraulic pump have the following structure:

n_m＝n_p (4)

the relation between the discharge capacity of the hydraulic pump and the discharge capacity of the hydraulic motor obtained by the joint type (1) to (4) is shown as the formula (5):

V_pis the displacement of a hydraulic pump, V_mIs the displacement of the hydraulic motor.

According to the formula (5), the matching of the input energy and the hydraulic power of the hydraulic motor can adapt to the large-range change of the diversion pressure and the thrust of the engine only by properly taking the displacement ratio of the hydraulic pump and the hydraulic motor according to the thrust adjusting working condition.

The method for keeping the rotating speed of the power assembly constant is to serially connect a constant speed valve at the oil inlet of the hydraulic motor,the constant-speed valve consists of a fixed-differential pressure reducing valve and a fixed throttle orifice, and the fixed-differential pressure reducing valve keeps the front and back pressure difference of the fixed throttle orifice constant, so that the flow rate of oil is constant. If the kerosene pressure p is introduced_mDecreasing, the pressure p at the lower end of the valve core of the constant speed valve_v1Will be reduced therewith, the pressure p at the lower end of the valve core_v1With the pressure p at the upper end of the spool_v2The difference in (c) decreases. Under the action of spring, the whole valve body moves downwards, and the valve core is opened x_vIncreased flow rate Q through the constant speed valve_mIncrease, in turn, p_v1Increase, p_v1And p_v2The difference in (c) is reduced and a new equilibrium is reached and vice versa.

The characteristic functions of the constant-speed valve are as equations (6) to (8).

A_s(p_v1-p_v2)＝K_sx_s+F_f(x_v) (8)

Wherein A is_sCross-sectional area of constant-speed valve spool, K_sConstant velocity valve internal spring rate, x_sFor constant rate of pre-compression of the valve spring, F_f(x_v) Is the hydraulic power at the valve core of the constant speed valve. C_d0To fix the flow coefficient of the orifice, ρ is the density of the tapped kerosene. C_svIs the flow coefficient at the valve core of the constant-speed valve, W_svIs a fixed orifice area gradient. A. the₀The cross-sectional area of the orifice is fixed for the constant speed valve.

Equation (6) represents the flow rate from the engine into the constant speed valve spool, and equation (7) represents the flow rate through the fixed orifice. Pressure drop delta p at a fixed orifice of a constant speed valve_vSubstantially unchanged, and can be regarded as a constant, the flow Q in the formula (7)_mIs a constant. To ensure the flow Q in formula (6)_mConstant rate valve spool opening x_vWill follow the pressure p of the drained kerosene_mAnd (4) changing.

Equation (8) is a force balance equation at both sides of the constant speed valve spool. Generally, the spring force is much greater than the hydraulic force F at the spool_f(x_v) The pressure drop deltap at the fixed orifice of the constant-speed valve_vCan be approximated by equation (9), the pressure drop Δ p over the spool_sAs equation (10), the pressure drop Δ p over the hydrostatic machine_mAs shown in formula (11).

Thus diverting the high pressure kerosene pressure p_mCan be expressed as:

as can be seen from equation (12), only the high pressure kerosene pressure p is directed_mAnd constant speed valve spool opening x_vFor variable quantities, i.e. constant speed valves, the change in the pilot pressure can be accommodated by adjusting the spool opening.

As shown in fig. 3, the energy matching method of the present invention includes the following steps:

acquiring a continuous swing speed omega of a servo mechanism, a swing force arm R of the servo mechanism, energy parameters and structural parameters of the servo mechanism; the energy parameters comprise the pressure p of the drainage kerosene_mDrainage oil return pressure p_m0Rated system operating pressure p_pHydraulic pump return pressure p_p0Pressure drop delta p at fixed orifice of constant speed valve_vHydraulic motor comprehensive efficiency eta_mHydraulic motor volumetric efficiency eta_mvHydraulic pump comprehensive efficiency eta_pLiquid medicineVolumetric efficiency eta of the pump_pvThe working speed n of the hydraulic pump_pWorking speed n of hydraulic motor_m(ii) a The structural parameters include the actuator piston area A;

step two, calculating the displacement V of the hydraulic pump according to the continuous swing speed index omega of the servo mechanism, the swing force arm R of the servo mechanism, the energy parameter and the structural parameter of the servo mechanism, which are obtained in the step one_pIs selected as a minimum design value of the hydraulic pump, and a displacement V of the hydraulic pump meeting the requirement is selected_p', a certain margin can be reserved;

displacement V of hydraulic pump_pSatisfy the requirement of

Step three, the hydraulic motor and the hydraulic pump adopt coaxial design, namely n_m＝n_pAnd considering the power balance relation between the output power of the hydraulic motor and the input power of the hydraulic pump, selecting the displacement V 'of the hydraulic pump according to the step two'_pTo calculate the displacement V of the hydraulic motor_mIs selected as a minimum design value of (1), and one hydraulic motor displacement V 'meeting the requirement is selected from the minimum design values'_mA certain margin can be reserved;

displacement V of hydraulic motor_mSatisfy the requirement of

Step four, selecting the displacement V 'of the hydraulic pump according to the step two and the step three'_pAnd hydraulic motor displacement V'_mAnd verifying the constant speed function under the change of the drainage pressure, and if the constant speed function passes the change of the drainage pressure, finishing the energy matching.

In step four, the selected hydraulic pump displacement V 'is verified using the following method'_pAnd hydraulic motor displacement V'_mWhether it is appropriate:

s1, according to the selected hydraulic pump displacement V'_pAnd hydraulic motor displacement V'_mCalculating the cross-sectional area A of the fixed orifice of the constant-speed valve₀And the pressure drop Δ p over the hydraulic motor_m；

S2, setting the pressure drop delta p at the fixed throttle of the constant speed valve_v2MPa, drainage kerosene pressure p_mThe variation range of (1) is 19-24 MPa, and the pressure drop delta p on the hydraulic motor obtained by combining S1_mCalculating the pressure drop Deltap on the spool of the constant speed valve_sA range of (d);

Δp_s＝p_m-p_m0-Δp_v-Δp_m

s3, fixing the orifice according to the cross-sectional area A of the constant speed valve₀And pressure drop Δ p across the spool of the constant speed valve_sCalculating the constant speed valve spool opening x_vA range of (d);

s4, opening x of the valve core of the constant speed valve obtained in S3_vIs within a reasonable range of 0.2-1.5 mm, the discharge volume V of the selected hydraulic pump is considered_p' and hydraulic motor displacement V_m' proper, otherwise, reselection is required.

Example (b):

the design of the displacement of the hydraulic pump and the displacement of the hydraulic motor and the matching calculation flow of the drainage pressure and the opening of the valve core of the constant-speed valve are shown in figure 3. The main design parameters of the servo mechanism under the thrust adjusting working condition of the engine are shown in the table 1.

TABLE 1 Servo mechanism Main design parameters

According to different drainage kerosene pressures, the internal parameters of the hydraulic motor are calculated, and the results are shown in the table 2. It can be clearly seen that the constant speed valve can adjust the pressure drop at the valve body by changing the opening of the valve core to adapt to different pressures of the drained kerosene.

TABLE 2 Main calculation parameters of hydraulic motor

Experiments prove that the parameter design can adapt to the pressure change of the drainage kerosene, the reasonable matching of the power of the hydraulic energy and the power of the kerosene energy is realized, the oil supply pressure of the servo valve is ensured to be in a rated design working condition, and the constant rotating speed of the power assembly can be kept.

The invention can quickly determine the reasonable ratio of the discharge capacities of the hydraulic pump and the hydraulic motor according to the variation range of the pressure of the drainage kerosene, ensure that the oil supply pressure of the servo valve is in a rated design working condition, realize the matching of the drainage energy power and the hydraulic energy power, and keep the rotating speed of the power assembly constant through the constant-speed valve at the oil inlet of the hydraulic motor.

Those skilled in the art will appreciate that the invention may be practiced without these specific details.