Device and test method for verifying the control law of autorotation descent of turboshaft engine

Abstract

The present invention discloses a device and a test method for verifying the autorotation and descent control law of a turboshaft engine, comprising a central transmission shaft, a first power mechanism, a second power mechanism, a dynamometer assembly and a load rod, wherein the first power mechanism comprises a turboshaft engine, a first transmission shaft, a first clutch and a first controller, and the first transmission shaft is controlled to engage / disengage with the central transmission shaft by the first clutch, and the second power mechanism comprises a motor, a second transmission shaft and a second controller; the device can truly simulate the change of the turboshaft engine load during the autorotation and descent of a helicopter and its exit process, thereby verifying the autorotation and descent control law, providing a basis for the design and improvement of the autorotation and descent control law, and effectively avoiding the risks brought by flight verification.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopters, and in particular to a device for verifying the autorotation and gliding control law of a turboshaft engine. In addition, the present invention also relates to a test method using the device for verifying the autorotation and gliding control law of a turboshaft engine. Background Art

[0002] The turboshaft engine is one of the main power sources of helicopters. Its typical features are: a power turbine is installed after the gas generator, so that the high-temperature and high-pressure gas is further expanded in the power turbine, and the power is output through the power turbine output shaft. The power output of the turboshaft engine power turbine is transmitted to the helicopter rotor and other rotating parts through the helicopter transmission system. The helicopter rotor collective pitch will change with the position of the collective pitch rod, which in turn affects the rotor load driven by the power turbine.

[0003] Figure 1 The control principle of a typical turboshaft engine is given. Turboshaft engines generally use constant power turbine speed control to maintain the helicopter's rotor speed at a fixed speed, that is, the speed reference value Np0, which can effectively improve the aerodynamic efficiency of the engine power turbine and the helicopter rotor, and avoid the helicopter and engine's rotation system working near the critical speed. On the basis of constant power turbine speed control, the engine control system will make advance compensation for the engine's fuel supply according to the signal of the collective pitch lever, that is, perform collective pitch compensation, to adapt to the load changes caused by the change in the rotor collective pitch, such as Figure 1 As shown. In the process of quickly pushing up or pulling down the collective pitch lever, the total torque of the helicopter rotor changes very quickly, which will cause the power turbine speed Np to change. The engine control system will determine the target acceleration rate Ngdot0 of the gas generator rotor based on the difference between Np and the speed reference value Np0 and the collective pitch compensation requirement, and then use the difference between Ngdot0 and the actual acceleration rate Ngdot to determine the change in fuel flow △Wf, adjust the gas generator speed Ng and other parameters to prevent the power turbine speed and rotor speed from exceeding the acceptable range.

[0004] Autorotation is a special working state of helicopters that distinguishes them from general fixed-wing aircraft. Autorotation may occur during helicopter maneuvering or rapid landing. At the same time, helicopters do not have the ejection and life-saving equipment of fixed-wing aircraft. In the event of all engine failures, autorotation landing is the only way to ensure the safety of the helicopter. Therefore, simulating helicopter autorotation and exit has become an important subject in helicopter flight training. When simulating autorotation, the helicopter will rush to the ground quickly, and the engine will be in a low power state. After exiting the autorotation, the engine will accelerate to a higher power state, so this is a high-risk subject.

[0005] To simulate an autorotation descent, the pilot will quickly pull down the collective pitch lever to reduce the collective pitch of the helicopter rotor. The helicopter will lower its altitude due to the reduction in lift, and the airflow will exert force on the rotor from bottom to top, thereby converting the potential energy of the helicopter into the kinetic energy of the rotor's autorotation. When the rotor is sufficient to achieve autorotation, the helicopter is in an autorotation descent state. In the process of entering the autorotation descent, the rotor speed will gradually increase and exceed the speed corresponding to the power turbine speed reference value. Under the action of constant power turbine speed control, the power turbine speed of the engine will eventually return to the reference value, thereby forming a speed difference, causing the clutch between the engine and the helicopter transmission system to disengage. At this time, the engine is in a lower working state due to the lack of rotor load. When exiting the autorotation descent, the pilot may need to quickly push up the collective pitch lever. The rotor speed decreases due to the increase in collective pitch, causing the clutch between the engine and the helicopter transmission system to re-engage. After engagement, the power turbine speed will be subject to a sharp increase in load. A typical autorotation descent and exit process is as follows: Figure 2 shown.

[0006] During the autorotation descent, the power turbine speed is no longer affected by the rotor collective pitch, and the collective pitch compensation is generally set to 0. When exiting the autorotation descent, the load on the power turbine increases sharply, and it is necessary to prevent the power turbine speed from sagging too much. The general method is to increase the power turbine output power in advance to cater to the rotor load. To achieve the above functions, the maximum threshold value CLPmax and the minimum threshold value CLPmin of the collective pitch lever CLP are set in the engine control system for the autorotation descent process. CLPmax corresponds to the state of re-engagement of the helicopter clutch, which can be determined according to the characteristics of the helicopter rotor. When CLP is greater than CLPmax, the collective pitch compensation adopts 100% of the normal compensation amount. More importantly, in order to increase the power in advance and improve the adaptability of the control law to different conditions, it is necessary to reasonably determine the specific value of CLPmin and the collective pitch compensation between CLPmin and CLPmax.

[0007] If the CLPmin value is too high and the total distance compensation between CLPmin and CLPmax is too small, the engine power may be insufficient during meshing, resulting in excessive droop of the power turbine speed. If the CLPmin value is too small and the total distance compensation between CLPmin and CLPmax is too large, the engine power may be too large, resulting in the power turbine speed exceeding the acceptable range, and even causing serious overspeed.

[0008] Therefore, it is crucial to design special control laws for turboshaft engines for the autorotation descent and its exit process. At present, the control laws for the autorotation descent and its exit process are mainly verified by combining semi-physical simulation of the engine control system with flight verification. However, the semi-physical simulation of the engine control system is limited by the accuracy of the model, and direct flight verification will face greater risks. Summary of the invention

[0009] The present invention provides a device for verifying the control law of autorotation descent of a turboshaft engine, so as to solve the problem that the prior art verifies the control law of autorotation descent and its exit process, mainly by combining semi-physical simulation of the engine control system with flight verification; however, the semi-physical simulation is subject to the accuracy of the model, and the control law verified by the simulation often needs to be adjusted after flight verification, and during the flight verification, the power turbine speed may excessively droop or overspeed, bringing a greater technical problem of flight risk.

[0010] According to one aspect of the present invention, there is provided a device for verifying the control law of autorotation and gliding of a turboshaft engine, comprising a central transmission shaft, a first power mechanism for driving the central transmission shaft, a second power mechanism for driving the central transmission shaft, a dynamometer assembly connected to the central transmission shaft for simulating a helicopter rotor and measuring torque, and a load rod for simulating a helicopter collective pitch rod, wherein the first power mechanism comprises a turboshaft engine, a first transmission shaft for driving the central transmission shaft, a first clutch for connecting the turboshaft engine and the first transmission shaft, and a first controller for receiving a signal from the load rod to control the rotation speed of the turboshaft engine, and the turboshaft engine is controlled to engage / disengage with the first transmission shaft through the first clutch, and the second power mechanism comprises a motor, a second transmission shaft for driving the central transmission shaft, and a second controller for receiving a signal from the load rod to control the rotation speed of the motor.

[0011] Furthermore, a first bevel gear is arranged on the end of the first transmission shaft away from the first clutch, a second bevel gear is arranged on the end of the second transmission shaft away from the motor, a third bevel gear is arranged on the first end of the central transmission shaft, and the first bevel gear and the second bevel gear are both meshed with the third bevel gear.

[0012] Furthermore, the motor is connected to the second transmission shaft via a gear box, and a second clutch is disposed on the gear box, and the second transmission shaft is controlled to engage / disengage with the motor via the second clutch.

[0013] Furthermore, the dynamometer assembly includes a hydraulic dynamometer for simulating the load of a helicopter rotor, a torsion disc for measuring the torque of the hydraulic dynamometer, a flywheel for simulating the rotational inertia of the helicopter rotor, and a third controller for switching the control mode of the hydraulic dynamometer. The hydraulic dynamometer, the torsion disc and the flywheel are connected in sequence through a rotor member, the flywheel is connected to the second end of the central transmission shaft, and the third controller is communicatively connected to the load rod.

[0014] Furthermore, the control modes of the third controller include a valve position mode, a constant speed control mode and a torque closed-loop control mode, and the control modes of the second controller include a motor torque closed-loop control mode and a motor speed control mode.

[0015] According to another aspect of the present invention, a test method for verifying the autorotation and descent control law of a turboshaft engine is also provided, using the above-mentioned device for verifying the autorotation and descent control law of a turboshaft engine, comprising the following steps:

[0016] S1. According to the data provided by the helicopter, the maximum threshold value CLPmax, the minimum threshold value CLPmin and the collective pitch compensation value of the collective pitch lever position CLP are written into the first controller. When CLPmin≤the load lever position CLP value<CLPmax, the collective pitch compensation value is set to 30% to 80% of the normal compensation value according to the calculation result;

[0017] S2, stabilize the speed of the turboshaft engine to the speed reference value Np0, select the valve position mode of the third controller, operate the water inlet valve opening knob on the third controller interface to obtain the minimum valve opening of the hydraulic dynamometer, and after stable operation for 2-3 minutes, obtain the minimum torque M0 of the hydraulic dynamometer through the torque measuring disk;

[0018] S3, setting the load rod position CLP value corresponding to the minimum torque M0 of the hydraulic dynamometer to CLPmax, and setting the control rule for the load rod position CLP value < CLPmax interval, so that the torque closed-loop control target value of the hydraulic dynamometer in this interval is maintained at the minimum torque M0;

[0019] S4. When the load rod position CLP value is ≥ CLPmax, the second controller adopts the motor torque closed-loop control mode, and calculates the motor torque value M1 when the hydraulic dynamometer is the minimum torque M0 according to the transmission ratio of the gearbox, and uses M1 as the target value of the motor torque closed-loop control; when the load rod position CLP value is < CLPmax, the second controller adopts the motor speed control mode, and calculates the motor speed value V0 when the speed of the turboshaft engine is ≥ 101% Np0 according to the transmission ratio of the gearbox, and uses V0 as the motor speed control target value;

[0020] S5. Setting the relationship between the load rod position CLP value and the motor torque in the second controller, when the load rod position CLP value ≥ CLPmax, the torque output by the motor makes the output shaft speed of the hydraulic dynamometer under the condition of minimum torque M0 equal to the speed reference value Np0 of the turboshaft engine; when the load rod position CLP value < CLPmax, the torque output by the motor makes the output speed of the hydraulic dynamometer under the condition of minimum torque M0 greater than or equal to 101% Np0;

[0021] S6, push up the load rod to make the load rod position CLP value ≥ CLPmax, start the turboshaft engine, run it to the flight slow state, and verify whether the speed of the turboshaft engine and the speed of the hydraulic dynamometer are both the speed reference value Np0;

[0022] S7, pull down the load rod so that the load rod position CLP value = 0°, the hydraulic dynamometer will be maintained at the minimum torque M0 state, the motor output torque increases, so that the speed of the hydraulic dynamometer is higher than the speed reference value Np0 of the turboshaft engine, verify whether the first transmission shaft is disengaged from the turboshaft engine, and whether the speed of the turboshaft engine is finally stabilized to the speed reference value Np0;

[0023] S8. In the range of 0°≤CLP value of load rod position<CLPmin, move the load rod to verify whether the parameters of the turboshaft engine change and whether the total pitch compensation amount is 0;

[0024] S9, pushing the load lever position CLP value from 0° to the high-power state position of the turboshaft engine, re-engaging the first transmission shaft with the turboshaft engine through the first clutch, and simulating the continued increase of the helicopter rotor collective pitch after engagement, and verifying whether the fluctuation of the power turbine speed is within an acceptable range during this process;

[0025] S10, increasing the motor speed control target value V0 of the motor, and verifying the rationality of the autorotation glide control law when the turboshaft engine re-engages at different speeds.

[0026] Further, in the step S9, verifying whether the fluctuation of the power turbine speed is within an acceptable range specifically includes: if the speed of the turboshaft engine drops too much, reducing CLPmin in the first controller setting, or increasing the collective pitch compensation amount between CLPmin and CLPmax; if the speed of the turboshaft engine overspeeds, increasing CLPmin in the first controller setting, or reducing the collective pitch compensation amount between CLPmin and CLPmax.

[0027] Furthermore, in step S9, the load rod position CLP value is pushed up from 0° to the high-power position of the turboshaft engine, and the push-up time is 0.5-20 seconds.

[0028] Furthermore, in step S9, the load rod position CLP value is pushed up from 0° to the high-power position of the turboshaft engine, and the push-up time is verified starting from 20 seconds, and then verified step by step by 0.5 seconds each time, and finally multiple verifications are performed with 0.5 seconds.

[0029] Furthermore, in step S5, when the load rod position CLP value is less than CLPmax, the torque output by the motor should make the output speed of the hydraulic dynamometer under the condition of minimum torque M0 be 102% Np0.

[0030] The present invention has the following beneficial effects:

[0031] The device for verifying the control law of autorotation and descent of a turboshaft engine of the present invention comprises a first transmission shaft and a second transmission shaft respectively located on both sides of a central transmission shaft, the central transmission shaft is used to realize the convergence of torque, and can converge the torque from the first transmission shaft and the second transmission shaft to a central transmission shaft, the turboshaft engine is connected to the first clutch through a coupling, the first clutch is connected to the first transmission shaft through a coupling or a spline structure, the torque generated by the turboshaft engine is transmitted to the dynamometer assembly through the first transmission shaft and the central transmission device, the motor is connected to the second transmission shaft through a coupling or a spline structure, and the torque generated by the motor is transmitted to the dynamometer assembly through the second transmission shaft and the central transmission device; the load rod is used to simulate the collective pitch rod on the helicopter, and the position and speed signal of the load rod will be transmitted to the first controller, the second controller and the dynamometer assembly; the first controller is used to receive the signal from the load rod, control the parameters such as the fuel flow rate of the turboshaft engine, so that the power turbine speed of the turboshaft engine is maintained at a fixed speed reference value Np0, and the speed reference value Np0 does not change with the change of the load rod position; when the speed of the turboshaft engine output shaft is higher than the speed of the central transmission shaft, the first The clutch is in an engaged state, so that the first transmission shaft drives the central transmission shaft, and the torque of the turboshaft engine output shaft is transmitted to the central transmission shaft to drive the central transmission shaft to rotate; when the speed of the central transmission shaft is higher than the speed of the turboshaft engine output shaft, the first clutch is disengaged, and the central transmission shaft is driven by the motor; the second controller is used to receive a signal from the load rod, and perform closed-loop control on the speed and torque of the motor, and the torque target value changes with the change of the load rod position; the output speed of the motor is adjusted by the second controller, so that the speed of the dynamometer component and the first transmission shaft is higher than the speed reference value Np0 of the turboshaft engine, so as to realize the disengagement of the first clutch; after the load is quickly pushed up, the second controller only outputs a lower torque, the speed of the dynamometer component and the first transmission shaft is reduced, and the first clutch is engaged; it has a simple structure and is easy to operate. By controlling the engagement state of the turboshaft engine and the first transmission shaft, it can truly simulate the helicopter's autorotation descent and its exit process during the bench test, so that the autorotation descent control law can be fully verified and optimized before the test flight, providing a basis for the design and improvement of the autorotation descent control law, and can effectively avoid the risks brought by flight verification.

[0032] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] Figure 1 This is the control schematic diagram of a typical turboshaft engine;

[0035] Figure 2 This is a schematic diagram of a typical autorotation descent and exit process;

[0036] Figure 3 It is a structural schematic diagram of a device for verifying the autorotation and gliding control law of a turboshaft engine according to a preferred embodiment of the present invention;

[0037] Figure 4 It is a schematic structural diagram of a central transmission shaft according to a preferred embodiment of the present invention.

[0038] Legend:

[0039] 1. Central transmission shaft; 11. Third bevel gear; 2. First power mechanism; 21. Turboshaft engine; 22. First transmission shaft; 221. First bevel gear; 23. First clutch; 24. First controller; 3. Second power mechanism; 31. Motor; 32. Second transmission shaft; 321. Second bevel gear; 33. Second clutch; 34. Second controller; 35. Gearbox; 4. Dynamometer assembly; 41. Hydraulic dynamometer; 42. Flywheel; 43. Torsion measuring disc; 44. Third controller; 5. Load rod. DETAILED DESCRIPTION

[0040] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0041] like Figure 3 and Figure 4 As shown, the device for verifying the autorotation and gliding control law of a turboshaft engine in this embodiment includes a central transmission shaft 1, a first power mechanism 2 for driving the central transmission shaft 1, a second power mechanism 3 for driving the central transmission shaft 1, a dynamometer assembly 4 connected to the central transmission shaft 1 for simulating a helicopter rotor and measuring torque, and a load rod 5 for simulating a helicopter collective pitch rod. The first power mechanism 2 includes a turboshaft engine 21, a first transmission shaft 22 for driving the central transmission shaft 1, a first clutch 23 for connecting the turboshaft engine 21 and the first transmission shaft 22, and a first controller 24 for receiving a signal from the load rod 5 to control the rotation speed of the turboshaft engine 21. The first clutch 23 controls the first transmission shaft 22 to engage / disengage with the central transmission shaft 1. The second power mechanism 3 includes a motor 31, a second transmission shaft 32 for driving the central transmission shaft 1, and a second controller 34 for receiving a signal from the load rod 5 to control the rotation speed of the motor 31.

[0042] In the device for verifying the control law of the autorotation and descent of the turboshaft engine of this embodiment, the first transmission shaft 22 and the second transmission shaft 32 are respectively located on both sides of the central transmission shaft 1. The central transmission shaft 1 is used to realize the convergence of torque, and can converge the torque from the first transmission shaft 22 and the second transmission shaft 32 to a central transmission shaft 1. The turboshaft engine 21 is connected to the first clutch 23 through a coupling, and the first clutch 23 is connected to the first transmission shaft 22 through a coupling or a spline structure. The torque generated by the turboshaft engine 21 is transmitted to the dynamometer component 4 through the first transmission shaft 22 and the central transmission device 1, and the motor 31 is connected to the second clutch 23 through a coupling or a spline structure. The transmission shaft 32 is connected, and the torque generated by the motor 31 is transmitted to the dynamometer assembly 4 through the second transmission shaft 32 and the central transmission device 1; the load rod 5 is used to simulate the collective pitch rod on the helicopter, and the position and speed signal of the load rod 5 will be transmitted to the first controller 24, the second controller 34 and the dynamometer assembly 4; the first controller 24 is used to receive the signal from the load rod 5, control the fuel flow and other parameters of the turboshaft engine 21, so that the power turbine speed of the turboshaft engine 21 is maintained at a fixed speed reference value Np0, and the speed reference value Np0 does not change with the change of the position of the load rod 5; when the output shaft speed of the turboshaft engine 21 is higher than the speed of the central transmission shaft 1 When the first clutch 23 is in the engaged state, the first transmission shaft 22 drives the central transmission shaft 1, and the output shaft torque of the turboshaft engine 21 is transmitted to the central transmission shaft 1, driving the central transmission shaft 1 to rotate; when the speed of the central transmission shaft 1 is higher than the output shaft speed of the turboshaft engine 21, the first clutch 23 is disengaged, and the central transmission shaft 1 is driven by the motor 31; the second controller 34 is used to receive the signal from the load rod 5, and perform closed-loop control on the speed and torque of the motor 31, and the torque target value changes with the position of the load rod 5; the output speed of the motor 31 is adjusted by the second controller 34, so that the speed of the dynamometer assembly 4 and the first transmission shaft 22 It is higher than the speed reference value Np0 of the turboshaft engine 21, so that the first clutch 23 is disengaged; after the load 5 is pushed up quickly, the second controller 34 only outputs a lower torque, the speed of the dynamometer component 4 and the first transmission shaft 22 is reduced, and the first clutch 23 is engaged; it has a simple structure and is easy to operate. By controlling the engagement state of the turboshaft engine 21 and the first transmission shaft 22, it can truly simulate the helicopter's autorotation and descent and its exit process during the bench test, so that the autorotation and descent control law can be fully verified and optimized before the test flight, providing a basis for the design and improvement of the autorotation and descent control law, and effectively avoiding the risks brought by flight verification.

[0043] In this embodiment, a first bevel gear 221 is arranged on the end of the first transmission shaft 22 away from the first clutch 23, a second bevel gear 321 is arranged on the end of the second transmission shaft 32 away from the motor 31, and a third bevel gear 11 is arranged on the first end of the central transmission shaft 1, and the first bevel gear 221 and the second bevel gear 321 are both engaged with the third bevel gear 11; the engagement is achieved through the bevel gear structure, the structure is simple, and the turboshaft engine 21 and the motor 31 can be respectively arranged on both sides of the central transmission shaft 1, which is easy to install.

[0044] In this embodiment, the motor 31 is connected to the second clutch 33 via a gear box 35; the gear box 35 is connected to the second clutch 33 via a coupling, which can reduce the rotation speed from one side of the motor 31 and increase the torque.

[0045] The motor 31 is connected to the second transmission shaft 32 through a gear box 35. The gear box 35 is provided with a second clutch 33, and the second transmission shaft 32 is controlled to engage / disengage with the motor 31 through the second clutch 33; the gear box 35 is connected to the second clutch 33 through a coupling, which can reduce the rotation speed from one side of the motor 31 and increase the torque; when the output shaft speed of the gear box 35 is higher than the rotation speed of the central transmission shaft 1, the second clutch 33 is in an engaged state, so that the second transmission shaft 32 drives the central transmission shaft 1, and the output shaft torque of the gear box 35 is transmitted to the central transmission shaft 1, driving the central transmission shaft 1 to rotate; when the rotation speed of the central transmission shaft 1 is higher than the output shaft speed of the gear box 35, the second clutch 33 is in a disengaged state, preventing the central transmission shaft 1 from driving the motor to over-rotate; it has a simple structure and is easy to operate.

[0046] In this embodiment, the dynamometer assembly 4 includes a hydraulic dynamometer 41 for simulating the load of a helicopter rotor, a torsion plate 43 for measuring the torque of the hydraulic dynamometer 41, a flywheel 42 for simulating the moment of inertia of a helicopter rotor, and a third controller 44 for switching the control mode of the hydraulic dynamometer 41. The hydraulic dynamometer 41, the torsion plate 43 and the flywheel 42 are connected in sequence through a rotor member, the flywheel 42 is connected to the second end of the central transmission shaft 1, and the third controller 44 is communicatively connected to the load rod 5; the hydraulic dynamometer 41 is used as a dynamometer to simulate the rotor load of the helicopter; the flywheel 42 is used to simulate the moment of inertia of the helicopter rotor and the transmission system; the torsion plate 43 is used to measure the torque of the hydraulic dynamometer 41, and the measured torque can be transmitted to the third controller 44, thereby realizing torque closed-loop control of the hydraulic dynamometer 41; it can simulate the helicopter rotor and measure the torque.

[0047] In this embodiment, the control modes of the third controller 44 include valve position mode, constant speed control mode and torque closed-loop control mode, and the control modes of the second controller 34 include motor torque closed-loop control mode and motor speed control mode.

[0048] A test method for verifying the autorotation descent control law of a turboshaft engine, using the device for verifying the autorotation descent control law of a turboshaft engine as described above, includes the following steps:

[0049] Step 1: Referring to Table 1, according to the data provided by the helicopter side, write the collective pitch lever position CLPmax corresponding to the engagement of the helicopter clutch into the first controller 24; according to the semi-physical simulation results of the control system, preliminarily determine CLPmin and the collective pitch compensation amount, and write them into the first controller 24; when the collective pitch lever position CLP value < CLPmin, the collective pitch compensation is 0, that is, when the collective pitch lever moves in this interval during the test, there will be no additional fuel flow increase; when CLPmin ≤ collective pitch lever position CLP value < CLPmax, the collective pitch compensation amount is set to 30% to 80% of the normal compensation amount according to the calculation result, that is, 30% ≤ x ≤ 80%; when the collective pitch lever position CLP value > CLPmax, the collective pitch compensation amount is the normal value.

[0050] Table 1 Collective pitch compensation amount for autorotation descent control

[0051] Load lever (same as helicopter collective pitch lever) position Total distance compensation % CLP<CLPmin 0 CLPmin≤CLP<CLPmax X% CLP ≥ CLPmax 100%

[0052] Step 2: Start the turboshaft engine 21 and run it to the flight idle state. The output shaft speed of the turboshaft engine 21 is stabilized at the speed reference value Np0; at this time, the third controller 44 selects the valve position mode, operates the water brake 41 water inlet valve opening knob on the third controller 44 interface, obtains the minimum valve opening of the water brake 41, and after stabilizing for 2 - 3 minutes, the minimum torque M0 of the water brake 41 can be obtained through the torque measuring disc 43, and then the turboshaft engine 21 stops;

[0053] Step 3: In the third controller 44, set the law of the torque closed-loop control mode to determine the relationship between the torque of the water brake 41 and the collective pitch lever position CLP value; according to the data provided by the helicopter, determine the collective pitch lever position CLP value corresponding to the maximum torque of the output shaft of the turboshaft engine 21; according to the results of Step 1 and Step 2, set the collective pitch lever position CLP value corresponding to the minimum torque M0 of the water brake 41 as CLPmax; set the control law for the interval where the collective pitch lever position CLP value < CLPmax, so that the target value of the torque closed-loop control of the water brake 41 in this interval remains the minimum torque M0, to avoid control fluctuations of the water brake 41 caused by too low torque target values.

[0054] Step 4. When the load rod position CLP value ≥ CLPmax, the second controller 34 adopts the motor torque closed-loop control mode, and calculates the torque value M1 of the motor 31 when the hydraulic dynamometer 41 is the minimum torque M0 according to the transmission ratio of the gear box 35, and uses M1 as the target value of the motor torque closed-loop control; when the load rod position CLP value < CLPmax, the second controller 34 adopts the motor speed control mode, and calculates the speed value V0 of the motor 31 when the output shaft speed of the turboshaft engine 21 is ≥101%Np0 according to the transmission ratio of the gear box 35, and uses V0 as the target value of the motor speed control.

[0055] The switching of the control mode of the second controller 34 can be completed within 1ms. When the load rod position CLP value ≥ CLPmax, the motor 31 and the turboshaft engine 21 jointly drive the hydraulic dynamometer 41 to rotate; when the load rod position CLP value < CLPmax, the motor 31 drives the hydraulic dynamometer 41 to rotate at a speed higher than 100% Np0, and the output shaft of the turboshaft engine 21 will fluctuate in speed due to load changes, the first transmission shaft 22 is disengaged from the central transmission shaft 1, and the turboshaft engine 21 will return to a speed of 100% Np0.

[0056] Step five, setting the relationship between the load rod position CLP value and the torque of the motor 31 in the second controller 34, when the load rod position CLP value ≥ CLPmax, the torque output by the motor 31 should make the output shaft speed of the hydraulic dynamometer 41 under the condition of minimum torque M0 equal to the speed reference value Np0 of the turboshaft engine 21 speed; when the load rod position CLP value < CLPmax, the torque output by the motor 31 should make the output speed of the hydraulic dynamometer 41 under the condition of minimum torque M0 greater than or equal to 101% Np0.

[0057] Optionally, in step five, when the load rod position CLP value is less than CLPmax, the torque output by the motor 31 should make the output speed of the hydraulic dynamometer 41 under the condition of minimum torque M0 be 102% Np0.

[0058] Step 6: Push up the load rod 5 to make the load rod position CLP value ≥ CLPmax, start the turboshaft engine 21, run it to the flight slow state, and verify whether the speed of the turboshaft engine 21 and the speed of the hydraulic dynamometer 41 are both the speed reference value Np0.

[0059] Step seven, slowly pull down the load rod 5 so that the load rod position CLP value = 0°, the hydraulic dynamometer 41 will be maintained in the minimum torque M0 state, the output torque of the motor 31 will increase, and the speed of the hydraulic dynamometer 41 will be higher than the speed reference value Np0 of the turboshaft engine 21, verifying whether the first transmission shaft 22 is disengaged from the turboshaft engine 21, and whether the speed of the turboshaft engine 21 is finally stabilized to the speed reference value Np0.

[0060] Step 8: In the range of 0°≤load rod position CLP value<CLPmin, move the load rod 5 to verify whether the parameters of the turboshaft engine 21 are unchanged and whether the total pitch compensation amount is zero.

[0061] Step nine, push the load rod position CLP value from 0° to the high-power state position of the turboshaft engine 21, re-engage the first transmission shaft 22 with the turboshaft engine 21 through the first clutch 23, and simulate the continued increase of the helicopter rotor collective pitch after engagement. During this process, observe whether the fluctuation of the power turbine speed is within an acceptable range.

[0062] If the speed of the turboshaft engine 21 drops too much, CLPmin is reduced in the setting of the first controller 24, or the collective pitch compensation amount between CLPmin and CLPmax is increased; if the speed of the turboshaft engine 21 overspeeds, CLPmin is increased in the setting of the first controller 24, or the collective pitch compensation amount between CLPmin and CLPmax is reduced.

[0063] Push the load rod position CLP value from 0° to the high power position of the turboshaft engine 21, and the push-up time is 0.5-20 seconds.

[0064] The load rod position CLP value is pushed up from 0° to the high-power position of the turboshaft engine 21. The push-up time is verified starting from 20 seconds, then gradually decreased by 0.5 seconds each time, and finally verified at 0.5 seconds; the rationality of the autorotation descent control law of the turboshaft engine 21 under different push-rod times can be verified.

[0065] Step 10: Increase the motor speed control target value V0 of the motor 31 to verify the rationality of the autorotation glide control law when the turboshaft engine 21 re-engages at different speeds until the engagement speed requirement of the helicopter is met.

[0066] The test method for verifying the control law of the autorotation and gliding of the turboshaft engine of the present embodiment is as follows: when the load lever position CLP value is greater than or equal to the collective pitch lever position corresponding to the engagement of the helicopter clutch, the rotation speed of the turboshaft engine 21 and the rotation speed of the hydraulic dynamometer 41 are both the rotation speed reference value Np0 of the rotation speed of the turboshaft engine 21, and the motor 31 and the turboshaft engine 21 jointly drive the hydraulic dynamometer 41 to rotate; when the load lever position CLP value is less than the collective pitch lever position corresponding to the engagement of the helicopter clutch, the output torque of the motor 31 increases, so that the rotation speed of the hydraulic dynamometer 41 is higher than the rotation speed reference value Np0 of the turboshaft engine 21, the first transmission shaft 22 is disengaged from the central transmission shaft 1, and the hydraulic dynamometer 41 is driven by the motor 31. 1 rotates, and the speed of the turboshaft engine 21 finally stabilizes to the speed reference value Np0; pushing the load rod 5 from 0° to the high-power state position of the turboshaft engine 21 can realize the re-engagement of the first transmission shaft 22 and the turboshaft engine 21, and simulate the continued increase of the helicopter rotor collective pitch after engagement; by observing whether the fluctuation of the power turbine speed is within an acceptable range, the autorotation and descent control law of the turboshaft engine 21 is optimized; it can truly simulate the change of the turboshaft engine load during the helicopter's autorotation and descent and its exit process, and then realize the verification of the autorotation and descent control law, provide a basis for the design and improvement of the autorotation and descent control law, and can effectively avoid the risks brought by flight verification.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for verifying the control law of autorotation and descent of a turboshaft engine, characterized in that: The invention comprises a central transmission shaft (1), a first power mechanism (2) for driving the central transmission shaft (1), a second power mechanism (3) for driving the central transmission shaft (1), a dynamometer assembly (4) connected to the central transmission shaft (1) for simulating a helicopter rotor and measuring torque, and a load rod (5) for simulating a helicopter collective pitch rod, wherein the first power mechanism (2) comprises a turboshaft engine (21), a first transmission shaft (22) for driving the central transmission shaft (1), and a second power mechanism (3) for connecting the turboshaft engine (21) and the first transmission shaft (22). A first clutch (23) and a first controller (24) for receiving a signal from the load rod (5) to control the rotation speed of the turboshaft engine (21), wherein the turboshaft engine (21) is controlled to engage / disengage with the first transmission shaft (22) through the first clutch (23), and the second power mechanism (3) comprises a motor (31), a second transmission shaft (32) driven by the motor (31) to drive the central transmission shaft (1), and a second controller (34) for receiving a signal from the load rod (5) to control the rotation speed of the motor (31).

2. The device for verifying the autorotation and gliding control law of a turboshaft engine according to claim 1, characterized in that: A first bevel gear (221) is arranged on one end of the first transmission shaft (22) away from the first clutch (23), a second bevel gear (321) is arranged on one end of the second transmission shaft (32) away from the motor (31), a third bevel gear (11) is arranged on the first end of the central transmission shaft (1), and the first bevel gear (221) and the second bevel gear (321) are both meshed with the third bevel gear (11).

3. The device for verifying the autorotation and gliding control law of a turboshaft engine according to claim 1 or 2, characterized in that: The motor (31) and the second transmission shaft (32) are connected via a gear box (35); a second clutch (33) is arranged on the gear box (35); and the second clutch (33) is used to control the engagement / disengagement of the second transmission shaft (32) and the motor (31).

4. The device for verifying the autorotation and gliding control law of a turboshaft engine according to claim 3, characterized in that: The dynamometer assembly (4) comprises a hydraulic dynamometer (41) for simulating a helicopter rotor load, a torsion plate (43) for measuring the torque of the hydraulic dynamometer (41), a flywheel (42) for simulating the rotational inertia of the helicopter rotor, and a third controller (44) for switching a control mode of the hydraulic dynamometer (41); the hydraulic dynamometer (41), the torsion plate (43) and the flywheel (42) are connected in sequence via a rotor member; the flywheel (42) is connected to the second end of the central transmission shaft (1); and the third controller (44) is in communication connection with the load rod (5).

5. The device for verifying the autorotation and gliding control law of a turboshaft engine according to claim 4, characterized in that: The control mode of the third controller (44) includes a valve position mode, a constant speed control mode and a torque closed-loop control mode, and the control mode of the second controller (34) includes a motor torque closed-loop control mode and a motor speed control mode.

6. A test method for verifying the autorotation glide control law of a turboshaft engine, characterized in that: The device for verifying the autorotation and gliding control law of a turboshaft engine according to claim 5 comprises the following steps: S1. According to the data provided by the helicopter, the maximum threshold value CLPmax, the minimum threshold value CLPmin and the collective pitch compensation value of the collective pitch lever position CLP are written into the first controller (24). When CLPmin≤the load lever position CLP value<CLPmax, the collective pitch compensation value is set to 30% to 80% of the normal compensation value according to the calculation result. S2, stabilizing the speed of the turboshaft engine (21) to a speed reference value Np0, selecting a valve position mode on the third controller (44), operating the water inlet valve opening knob on the interface of the third controller (44), obtaining the minimum valve opening of the hydraulic dynamometer (41), and obtaining the minimum torque M0 of the hydraulic dynamometer (41) through the torque measuring disk (43) after stable operation for 2-3 minutes; S3, setting the load rod position CLP value corresponding to the minimum torque M0 of the hydraulic dynamometer (41) to CLPmax, and setting the control rule for the load rod position CLP value < CLPmax interval so that the torque closed-loop control target value of the hydraulic dynamometer (41) in this interval is maintained at the minimum torque M0; S4, when the load rod position CLP value is ≥ CLPmax, the second controller (34) adopts the motor torque closed-loop control mode, calculates the torque value M1 of the motor (31) when the hydraulic dynamometer (41) is the minimum torque M0 according to the transmission ratio of the gear box (35), and uses M1 as the target value of the motor torque closed-loop control; when the load rod position CLP value is < CLPmax, the second controller (34) adopts the motor speed control mode, calculates the speed value V0 of the motor (31) when the speed of the turboshaft engine (21) is ≥ 101% Np0 according to the transmission ratio of the gear box (35), and uses V0 as the motor speed control target value; S5. Setting a relationship between a load rod position CLP value and a torque of the motor (31) in the second controller (34), wherein when the load rod position CLP value is ≥ CLPmax, the torque output by the motor (31) makes the output shaft speed of the hydraulic dynamometer (41) equal to a speed reference value Np0 of the turboshaft engine (21) under a minimum torque M0 condition; and when the load rod position CLP value is < CLPmax, the torque output by the motor (31) makes the output speed of the hydraulic dynamometer (41) under a minimum torque M0 condition greater than or equal to 101% Np0. S6, pushing up the load rod (5) so that the load rod position CLP value ≥ CLPmax, starting the turboshaft engine (21), running it to a flight slow state, and verifying whether the speed of the turboshaft engine (21) and the speed of the hydraulic dynamometer (41) are both the speed reference value Np0; S7, pulling down the load rod (5) so that the load rod position CLP value = 0°, the hydraulic dynamometer (41) will be maintained at the minimum torque M0 state, the output torque of the motor (31) will increase, so that the speed of the hydraulic dynamometer (41) is higher than the speed reference value Np0 of the turboshaft engine (21), verifying whether the first transmission shaft (22) is disconnected from the turboshaft engine (21), and whether the speed of the turboshaft engine (21) is finally stabilized to the speed reference value Np0; S8, within the range of 0°≤CLP value of the load rod position<CLPmin, move the load rod (5) to verify whether the parameters of the turboshaft engine (21) change and whether the total pitch compensation amount is 0; S9, pushing the load lever position CLP value upward from 0° to a high-power state position of the turboshaft engine (21), reengaging the first transmission shaft (22) and the turboshaft engine (21) through the first clutch (23), and simulating a continued increase in the helicopter rotor collective pitch after engagement, during which process verifying whether the fluctuation of the power turbine rotation speed is within an acceptable range; S10, increasing the motor speed control target value V0 of the motor (31), and verifying the rationality of the autorotation glide control law when the turboshaft engine (21) re-engages at different speeds.

7. The test method for verifying the autorotation and gliding control law of a turboshaft engine according to claim 6, characterized in that: In the step S9, verifying whether the fluctuation of the power turbine speed is within an acceptable range specifically includes: if the speed of the turboshaft engine (21) drops too much, reducing CLPmin in the first controller (24) setting, or increasing the collective pitch compensation amount between CLPmin and CLPmax; if the speed of the turboshaft engine (21) overspeeds, increasing CLPmin in the first controller (24) setting, or reducing the collective pitch compensation amount between CLPmin and CLPmax.

8. The test method for verifying the autorotation and gliding control law of a turboshaft engine according to claim 7, characterized in that: In step S9, the load rod position CLP value is pushed up from 0° to a high-power position of the turboshaft engine (21), and the push-up time is 0.5-20 seconds.

9. The test method for verifying the autorotation and gliding control law of a turboshaft engine according to claim 8, characterized in that: In step S9, the load rod position CLP value is pushed up from 0° to the high power position of the turboshaft engine (21), and the push-up time is verified starting from 20 seconds, and then verified step by step by 0.5 seconds each time, and finally verified multiple times with 0.5 seconds.

10. The test method for verifying the autorotation and gliding control law of a turboshaft engine according to claim 6, characterized in that: In the step S5, when the load rod position CLP value is less than CLPmax, the torque output by the motor (31) should make the output speed of the hydraulic dynamometer (41) under the condition of minimum torque M0 be 102% Np0.

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