A demonstration experimental device for conservation of momentum based on the principle of a twin-rotor helicopter

Abstract

The invention discloses a momentum conservation demonstration experiment device based on the principle of a twin-rotor helicopter, which relates to the technical field of teaching aids for theoretical mechanics courses, and includes an upper rotor structure, a lower rotor structure, a tail rotor, a fuselage, and a base; the upper rotor structure includes a main shaft I, and the lower rotor structure includes a main shaft II, and the lower ends of the main shaft I and the main shaft II extend into the main shaft bearing seat inside the fuselage; the fuselage is provided with motors I and II for controlling the rotation of the main shaft I and the main shaft II respectively; the tail rotor is installed on the motor III, and the motor III is installed on the steering gear at the tail of the fuselage; the fuselage is provided with a conductive slip ring, and the rotor of the conductive slip ring is fixed to the lower part of the fuselage; the base is provided with a rectangular support frame assembly, and the rectangular support frame assembly is provided with a support column that can move up and down, and the stator of the conductive slip ring is installed at the upper end of the support column. The upper rotor structure, the lower rotor structure, and the tail rotor of the invention can be set separately according to the operator's requirements.

Description

Technical Field

[0001] The invention relates to the technical field of theoretical mechanics course teaching aids, in particular to a momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter. Background Art

[0002] In theoretical mechanics courses, conservation of angular momentum is one of the three major conservation laws in mechanics. Currently, there are four main experimental devices for conservation of angular momentum in experimental teaching.

[0003] The first type: a new type of quantitative verification of the law of conservation of momentum developed by Zhejiang University City College, application (patent) number: 201810039008.7. The device consists of a shooting gun base, a shooting gun support column, a shooting gun, a free-rotating disk, a bullet chamber, a photoelectric gate fixed disk, upper and lower wheel axle fixed columns, a free-rotating shaft, a wheel axle fixed column support leg and an electric control box; a leveling support leg is provided under the shooting gun base, and a balance hammer is provided on the shooting gun base; the shooting gun support column is fixed to the shooting gun base with a support column fixing screw, and the shooting barrel fixing screw is screwed to the shooting gun support column at the corresponding position of the shooting gun barrel of the shooting gun. The shooting gun rod hits the bullet and obtains a large momentum, and then enters the bullet chamber fixed at the edge of the free-rotating disk, so that the free-rotating disk obtains a momentum moment, and this momentum moment also includes the bullet itself, which essentially verifies the correctness of the law of conservation of momentum moment of the particle group.

[0004] The second type: The momentum conservation experiment instrument introduced in the "Self-braking Moment Conservation Demonstration Instrument" published by Ling Xianghu et al. of Jianghan Petroleum College in the 9th volume, issue 1 of "College Physics Experiment" in March 1996. The device consists of a rotating impeller connected to a micro motor through a hollow sleeve, and then fixed in the middle of a rotating beam, on which a battery, switch, and balancing screws are fixed; the above equipment is fixed to a circular chassis through ball bearings and conical support rods. When the rotating impeller rotates, the beam will rotate in the opposite direction of the impeller, thereby demonstrating the conservation of momentum.

[0005] The third type: The angular momentum demonstration device introduced in the article "Design of Angular Momentum Demonstration Instrument" published by Lang Cheng et al. of Jilin Institute of Chemical Technology in the journal "Physical Experiment" Vol. 24 No. 3 in March 2004. This device installs two identical wheels on a freely rotating beam, and uses two ropes to tie the two ends of a horizontal spring. The other ends of the ropes are tied to the shafts of the two wheels. Depending on the direction of the wire wrapped around the wheels, the two wheels can rotate in opposite or same directions. When rotating in the same direction, the free rotating beam drives the two wheels to rotate in opposite directions. When rotating in opposite directions, the rotating beam is stationary. The rotational inertia of the wheels can also be different to demonstrate the phenomenon that the angular momentum of the rotating beam changes when the speed is the same but the direction is opposite.

[0006] The fourth type: The torque mutation angular momentum conservation demonstration experiment device introduced in "A New Angular Momentum Conservation Demonstration Experiment Device" published by Lu Junling of Tsinghua University in the 7th issue of Volume 23 of the Journal of University Physics in July 2004. The device consists of a frame, a ball-bar system, a support rod equipped with a precision spherical bearing, and a soft filament. Two steel balls with a mass of m are connected by a light rigid rod with a length of 2l to form a ball-bar system. The midpoint of the ball-bar system is connected to a precision spherical bearing, and the fixed ball of the spherical bearing is connected to the support rod, which is fixed on the frame base. The first step is to operate the ball-bar system to deviate from the horizontal state and tilt. Due to the decrease in the moment of inertia, its rotation around the vertical axis gradually accelerates. The second step is to operate randomly during the high-speed rotation of the tilted ball-bar system around the vertical axis. After the experimenter suddenly lets go, the ball-bar system will perform uniform circular motion around the center in the plane determined by the instantaneous velocity of the connecting rod and the ball.

[0007] The first type of experimental equipment is based on the principle of a shooting gun. It has a relatively complex structure and is rarely seen in real life. It is highly professional. The second type of experimental instrument uses a single rotating impeller and only demonstrates the reverse rotation of the rotating beam when the rotor rotates. It is similar to a single-rotor helicopter model without a tail rotor, so it lacks the balancing effect of the tail rotor, the rotation speed is also uncontrollable, and there is no quantitative measurement of the parameters related to the moment of momentum. The third type of experimental equipment uses the pre-stored energy of the spring to make the same turntable rotate in different or the same direction, and observes the different rotation phenomena of the supporting rotating beam, thereby demonstrating the conservation of the moment of momentum; it can also change the rotation speed of the supporting rotating beam when the moment of inertia of the turntable changes, thereby demonstrating the law of conservation of the moment of momentum. However, the use of springs as energy cannot be demonstrated continuously, the rotation speed of the turntable cannot be controlled, and it cannot be controlled alone. At the same time, there is also a lack of quantitative measurement of the parameters related to the moment of momentum. The fourth type of experimental equipment is mainly aimed at the changes in the rotation speed and angle when the moment of inertia changes after the structure rotates, thereby demonstrating the law of conservation of the moment of momentum. However, it only demonstrates the phenomenon caused by the change in the magnitude of the moment of momentum, does not involve the phenomenon caused by the change in the direction of the moment of momentum, and lacks quantitative measurement of the parameters related to the moment of momentum. Summary of the invention

[0008] Purpose of the invention: In order to better demonstrate the application of the momentum moment principle in engineering, the present invention provides a momentum moment conservation demonstration experimental device based on the principle of a twin-rotor helicopter, so that the upper rotor structure, the lower rotor structure and the tail rotor can be individually set according to the operator's requirements.

[0009] Technical solution: A momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter, comprising an upper rotor structure, a lower rotor structure, a tail rotor, a fuselage and a base; the upper rotor structure comprises a main shaft I, the lower rotor structure comprises a main shaft II, the lower ends of the main shaft I and the main shaft II extend into the interior of the fuselage and are installed on the main shaft bearing seat in the fuselage; the fuselage is provided with a motor I and a motor II for controlling the rotation of the main shaft I and the main shaft II respectively; the tail rotor is installed on the motor III, and the motor III is installed on the steering gear at the tail of the fuselage; the fuselage is provided with a conductive slip ring, and the rotor of the conductive slip ring is fixed to the lower part of the fuselage; the base is provided with a rectangular support frame assembly, and the rectangular support frame assembly is provided with a support column that can move up and down, and the stator of the conductive slip ring is installed at the upper end of the support column.

[0010] Furthermore, a photoelectric encoder is fixed to the lower part of the fuselage.

[0011] Furthermore, the rectangular support frame assembly includes an upper fixed beam, a lower fixed beam, a movable beam and left and right guide light rods; the upper and lower ends of the guide light rod are connected to the upper fixed beam and the lower fixed beam respectively; the movable beam can move up and down along the guide light rod, and the two ends of the movable beam are connected to the two guide light rods respectively through linear bearings; a center hole that passes through the upper and lower parts is provided at the center of the upper fixed beam; the lower fixed beam is connected to the base; a multi-component force sensor is fixed on the upper side of the movable beam, and a transition pressure head is fixed on the lower side of the movable beam; a lift sensor is fixed on the upper side surface of the lower fixed beam; the movable beam is pressed on the lift sensor through the transition pressure head; a torque sensor is fixedly connected to the upper end of the support column, the torque sensor is fixedly connected to the stator of the conductive slip ring, and the lower end of the support column passes through the center hole and is fixedly connected to the multi-component force sensor.

[0012] Furthermore, the motor III is installed on the servo at the tail of the fuselage through a bracket, and a thrust sensor is provided on the bracket.

[0013] Furthermore, a rotor motor driver, a tail rotor motor driver and a servo driver are provided in the fuselage; the rotor motor driver is used to control the operation of the motors I and II; the tail rotor motor driver is used to control the operation of the motor III; and the servo driver is used to control the operation of the servo.

[0014] Furthermore, a wireless controller is provided in the fuselage, and the control lines of the rotor motor driver, tail rotor motor driver and servo driver are all connected to the wireless controller, and the wireless controller is connected to the main control computer via a wireless network; the power supplies of the rotor motor driver, tail rotor motor driver, servo driver and wireless controller are all provided through conductive slip rings; a wireless main control box is provided on the base; the photoelectric signal line of the photoelectric encoder, the signal line of the torque sensor, the signal line of the lift sensor, the signal line of the multi-component force sensor and the power line of the conductive slip ring stator are all connected to the wireless main control box, and the wireless main control box is connected to a 220V power line.

[0015] Furthermore, the upper rotor structure also includes a hub I, a pair of rotors I, a plurality of adjustment rods I and an adjustment disk I; the rotor I is installed on the hub I, the adjustment disk I is arranged below the hub I and parallel to the hub I, and the hub I is connected to the adjustment disk I through the adjustment rod I; the hub I and the adjustment disk I are fixed on the main shaft I; the lower rotor structure also includes a hub II, a pair of rotors II, an adjustment rod II, an adjustment disk II, and a main shaft II; the rotor II is installed on the hub II, the adjustment disk II is arranged below the hub II and parallel to the hub II, and the hub II is connected to the adjustment disk II through the adjustment rod II; the hub II and the adjustment disk II are fixed on the main shaft II.

[0016] Furthermore, the main shaft I 5 and the main shaft II 10 are located on the same axis, the main shaft II 10 is a hollow shaft, and the main shaft I 5 passes through the main shaft II 10; a synchronous gear pinion I is installed on the rotating shaft of the motor I, a synchronous gear large wheel I is installed at the lower end of the main shaft I, and the synchronous gear pinion I is connected to the synchronous gear large wheel I through a synchronous belt I; a synchronous gear pinion II is installed on the rotating shaft of the motor II, a synchronous gear large wheel II is installed at the lower end of the main shaft II, and the synchronous gear pinion II and the synchronous gear large wheel II are connected through a synchronous belt II.

[0017] Furthermore, the base is a tripod base, and three adjustable support feet are installed below the tripod base, and rollers are installed at the lower ends of the adjustable support feet.

[0018] Beneficial effects:

[0019] 1. In order to better demonstrate the application of the principle of momentum in engineering, the twin-rotor helicopter's coaxial twin-propeller design is changed to an independent-axis design. The rotation speed and direction of each rotor can be set individually according to the operator's requirements, and the tail rotor rotation speed and the direction of the tail rotor placed at the tail of the fuselage can be controlled separately;

[0020] 2. Four sensors that can measure different parameters are installed on the structure of the demonstration experimental device, which can quantitatively measure the rotation speed of the rotor and tail rotor, the lift generated by the rotor, the thrust generated by the tail rotor, the speed, direction, acceleration, torque and forward force of the fuselage rotation;

[0021] 3. The device of the present invention can demonstrate six modes. In different modes, different phenomena can be explained according to the principle of conservation of angular momentum, and how a helicopter uses the principle of conservation of angular momentum to adjust the lift of the fuselage, fix the flight direction of the fuselage, adjust the flight direction of the fuselage, adjust the forward force of the fuselage, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a structural diagram of the main control computer in the present invention;

[0024] Figure 3 for Figure 1 A magnified schematic diagram of part A;

[0025] Figure 4 for Figure 1 Schematic diagram of the enlarged portion B. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0027] like Figure 1 As shown, the present invention provides a momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter, including an upper rotor structure, a lower rotor structure, a tail rotor 40, a fuselage 44 and a base 32.

[0028] The upper rotor structure includes a main shaft I5, a hub I1, a pair of rotors I2, a plurality of adjustment rods I3 and an adjustment disk I4; the rotor I2 is installed on the hub I1, the adjustment disk I4 is arranged below the hub I1 and parallel to the hub I1, the hub I1 and the adjustment disk I4 are connected through the adjustment rod I3; the hub I1 and the adjustment disk I4 are fixed on the main shaft I5.

[0029] The lower rotor structure includes a main shaft II 10, a hub II 6, a pair of rotors II 7, a plurality of adjustment rods II 8 and an adjustment disk II 9; the rotor II 7 is mounted on the hub II 6, the adjustment disk II 9 is arranged below the hub II 6 and parallel to the hub II 6, the hub II 6 and the adjustment disk II 9 are connected through the adjustment rod II 8; the hub II 6 and the adjustment disk II 9 are fixed on the main shaft II 10.

[0030] A main shaft bearing seat 11, motor I1 2, motor II 13, rotor motor driver 36, tail rotor motor driver 38, steering gear driver 39 and conductive slip ring 20 are arranged inside the fuselage 44, and a steering gear 43 is arranged at the tail of the fuselage 44; the rotor of the conductive slip ring 20 is fixed to the lower part of the fuselage 44, and a photoelectric encoder 21 is also fixed to the lower part of the fuselage.

[0031] The lower ends of the main shaft I 5 and the main shaft II 10 extend into the interior of the fuselage 44 and are installed on the main shaft bearing seat 11 in the fuselage 44. The main shaft I 5 and the main shaft II 10 are located on the same axis, and the main shaft II 10 is a hollow shaft. The main shaft I 5 passes through the main shaft II 10; the rotor motor driver 36 is used to control the operation of the motor I 12 and the motor II 13; the motor I12 and the motor II 13 are used to control the rotation of the main shaft I 5 and the main shaft II 10 respectively; a synchronous gear pinion I14 is installed on the rotating shaft of the motor I12, and a synchronous gear wheel I16 is installed on the lower end of the main shaft I 5, and the synchronous gear pinion I14 is connected to the synchronous gear wheel I16 through a synchronous gear belt I15; a synchronous gear pinion II 17 is installed on the rotating shaft of the motor II 13, and a synchronous gear wheel II 17 is installed on the lower end of the main shaft II 10 18, the synchronous gear small wheel II 17 and the synchronous gear large wheel II 18 are connected by a synchronous toothed belt II 19.

[0032] The tail rotor 40 is mounted on the motor III 41, and the motor III 41 is mounted on the steering gear 43 through a bracket 42, and a thrust sensor is provided on the bracket 42; the tail rotor motor driver 38 is used to control the operation of the motor III 41; and the steering gear driver 39 is used to control the operation of the steering gear 43.

[0033] A rectangular support frame assembly is provided on the base 32, and the rectangular support frame assembly includes an upper fixed beam 24, a lower fixed beam 31, a movable beam 28, and two left and right guide light rods 25; the upper and lower ends of the guide light rod 25 are connected to the upper fixed beam 24 and the lower fixed beam 31 respectively; the movable beam 28 can move up and down along the guide light rod 25, and the two ends of the movable beam 28 are connected to the two guide light rods 25 respectively through linear bearings 27; a central hole penetrating up and down is provided at the center of the upper fixed beam 24; the lower fixed beam 31 is connected to the base 32. A multi-component force sensor 26 is fixed on the upper side of the movable beam 28, and a transition pressure head 29 is fixed on the lower side of the movable beam 28; a lift sensor 30 is fixed on the upper side of the lower fixed beam 31; the movable beam 28 presses on the lift sensor 30 through the transition pressure head 29.

[0034] The rectangular support frame assembly is provided with a support column 23 which can move up and down, the upper end of the support column 23 is fixedly connected with a torque sensor 22, the torque sensor 22 is fixedly connected to the stator of the conductive slip ring 20, and the lower end of the support column 23 passes through the center hole and is fixedly connected to the multi-component force sensor 26.

[0035] A wireless controller 37 is also provided in the fuselage 44 , and control lines of the rotor motor driver 36 , the tail rotor motor driver 38 , and the servo driver 39 are all connected to the wireless controller 37 , and the wireless controller 37 is connected to the main control computer 35 via a wireless network.

[0036] The power supplies of the rotor motor driver 36 , the tail rotor motor driver 38 , the steering gear driver 39 , and the wireless controller 37 are all provided through the conductive slip ring 20 .

[0037] A wireless main control box 33 is provided on the base 32; the photoelectric signal line of the photoelectric encoder 21, the signal line of the torque sensor 22, the signal line of the lift sensor 30, the signal line of the multi-component force sensor 26 and the power line of the stator of the conductive slip ring 20 are all connected to the wireless main control box 33, and the wireless main control box 33 is connected to a 220V power line 34.

[0038] The base 32 is a tripod base, and three adjustable support legs 45 are installed below the tripod base, and rollers are installed at the lower ends of the adjustable support legs 45. The adjustable support legs 45 can adjust the level of the base, and the adjustable support legs 45 are provided with rollers for easy transportation.

[0039] When performing a demonstration experiment, the working state of the present invention can be divided into six demonstration modes:

[0040] (1) Upper rotor structure state mode

[0041] When the rotor motor driver drives motor Ⅰ and hub Ⅰ alone, the upper rotor structure rotates clockwise, and the lift F and the drag moment M are generated due to air resistance. r The lift F will drive the entire fuselage, photoelectric encoder, torque sensor, support column, multi-component force sensor, moving beam, linear bearing and transition pressure head to rise. The lift sensor will measure the lift F at this time. The photoelectric encoder can measure the instantaneous speed v and acceleration a of the fuselage corner and their directions at this time. The torque sensor will measure the reverse torque M applied by motor I to the base. c , because the resistance is M r The fuselage will rotate in the opposite direction of the rotation of rotor I, and when it reaches a certain speed, that is, when the resistance couple formed by the rotation of the fuselage and the friction force formed by the conductive slip ring equals the force couple formed by the stroke, the speed is constant, a=0, and the corresponding software in the main control computer displays all variables (F, v, a, M c )’s change curve.

[0042] (2) Upper rotor structure + tail rotor balance state mode

[0043] In the first state, the tail rotor motor driver drives the tail rotor, and the servo drives the thrust sensor and bracket, the tail rotor motor and the tail rotor to automatically rotate to the left side of the fuselage. The wireless controller will adjust the speed of the tail rotor according to the speed measured by the photoelectric encoder. At this time, the thrust sensor can measure the thrust F of the tail rotor. t , when the thrust of the tail rotor F t The torque generated is M t Can offset air resistance r At this time, the fuselage is stationary, a = 0. If you need to change the flight direction θ, you can change the tail rotor thrust F by reducing or increasing the tail rotor speed. t and torque M t After reaching the specified angle, the fuselage needs to be balanced again using the principle of moment balance. The software in the main control computer displays all variables (F, F t ,v,a,M c ,θ) change curve.

[0044] (3) Lower rotor structure status mode

[0045] When the rotor motor driver drives motor II and hub II alone, the lower rotor structure rotates counterclockwise, and the lift F and the drag force M are generated due to air resistance. r The lift sensor will measure the lift F at this time, the photoelectric encoder can measure the instantaneous speed v and acceleration a and direction of the fuselage angle at this time, and the torque sensor can measure the reverse torque -M applied by motor II to the base c , because the resistance is even-M rThe fuselage will rotate in the opposite direction of rotor II, and when it reaches a certain speed, that is, when the resistance couple formed by the rotation of the fuselage and the friction force formed by the conductive slip ring are equal, the speed is constant, a=0, and the software in the main control computer displays all variables (F, v, a, M c )’s change curve.

[0046] (4) Lower rotor structure + tail rotor balance state mode

[0047] In the third state, the tail rotor motor driver drives the tail rotor, and the servo drives the thrust sensor and bracket, the tail rotor motor and the tail rotor to automatically rotate to the right side of the fuselage. The wireless controller will adjust the speed of the tail rotor according to the photoelectric encoder. At this time, the thrust sensor and bracket can measure the thrust of the tail rotor. When the thrust F of the tail rotor is t The generated couple - M t Can offset air resistance even-M r At this time, the fuselage is stationary, a = 0. If you need to change the flight direction θ, you can change the tail rotor thrust F by reducing or increasing the tail rotor speed. t and couple M t After reaching the specified angle, the fuselage needs to be balanced again using the principle of moment balance. The software in the main control computer displays the change curves of all variables.

[0048] (5) Dual rotor balance mode

[0049] When the rotor motor driver drives motor I, hub I, motor II, and hub II simultaneously, the upper rotor structure rotates clockwise and the lower rotor structure rotates counterclockwise. The upper and lower rotor structures will generate the same lift F1 and F2 and drag moment M due to air resistance. r1 、M r2 The lift sensor will measure the lift at this time as F = F1 + F2, the photoelectric encoder can measure the instantaneous velocity v and acceleration a and direction of the fuselage at this time, and the torque sensor will measure the reverse torque M applied by the fuselage to the base. c If the two rotors are loaded at the same speed and the wind angle is the same, the fuselage is stationary, M r1 =-M r2 , M c =0, v=0, a=0 and direction θ is stable. If you need to change the flight direction θ, you can change θ by reducing or increasing the speed of any rotor to make the upper and lower rotor force couples different. After reaching the specified angle, you need to balance the fuselage again using the principle of momentum balance (actual twin-rotor helicopters are generally coaxial and do not use this principle to adjust the direction). The software in the main control computer displays all variables (F, F t ,v,a,M c ,θ) change curve.

[0050] (6) Dual rotor + tail rotor mode

[0051] In the fifth state, the tail rotor motor driver drives the tail rotor. At this time, the servo drives the thrust sensor and bracket, the tail rotor motor and the tail rotor to automatically rotate to the rear of the fuselage. At this time, the tail rotor, as a rear propeller, will apply a thrust F to the tail of the fuselage. t , this thrust will be used as the forward force, and will change the forward force F in the fifth state. x ≠0, F y ≠0, change the flight direction θ and the fifth state, the software in the main control computer displays all variables (F, F t ,v,a,M c ,θ) change curve.

[0052] In order to better demonstrate the application of the principle of conservation of momentum on helicopters, the present invention simplifies the original model, changes each transmission mechanism to a separate control, and adds a force sensor and a speed sensor, so that some important parameters about the momentum can be measured. Not only can different motion phenomena be observed, but also the signals collected by each sensor can be displayed in the form of curves through the supporting software to see the change process of each parameter. Wireless signal communication is adopted, and no complicated wiring is required. It can work continuously by providing a DC power supply to the fuselage.

[0053] The present invention can explain different phenomena according to the principle of conservation of momentum in different demonstration modes, and explain how the helicopter uses the principle of conservation of momentum to adjust the lift of the fuselage, fix the flight direction of the fuselage, adjust the flight direction of the fuselage, adjust the forward force of the fuselage, etc. In different working modes, each rotor speed, fuselage reverse torque, fuselage lift, fuselage forward force, tail rotor thrust, fuselage instantaneous angle, rotation speed and torque can be quantitatively measured:

[0054] 1) In the first four modes, the rotation of the fuselage can be demonstrated based on the conservation of momentum when there is no tail rotor in different rotation directions of the rotor. The same momentum can also balance the fuselage principle for a twin-rotor helicopter in different rotation directions. In the upper rotor structure + tail rotor balance state and lower rotor structure + tail rotor balance state modes, the fuselage speed feedback signal can be used to control the tail rotor speed in a closed loop to balance the fuselage. When there is a tail rotor, explain the principle of the tail rotor balancing the fuselage based on the conservation of momentum principle;

[0055] 2) In modes (5) and (6), the tail rotor can be used as an auxiliary thrust when the twin rotors are working.

[0056] Through the experiments demonstrated by the present invention, the principle of balancing the fuselage of a single-rotor + tail-rotor helicopter according to the conservation of momentum can be mastered, as well as the principle of self-balancing fuselage of a double-rotor without tail-rotor and the principle of a double-rotor + tail-rotor helicopter, as well as the relevant mechanisms of helicopter heading control and lift generation can be mastered. Therefore, the device has good promotional properties.

[0057] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A demonstration experimental device for conservation of momentum based on the principle of a twin-rotor helicopter, characterized in that: It comprises an upper rotor structure, a lower rotor structure, a tail rotor (40), a fuselage (44) and a base (32); The upper rotor structure comprises a main shaft I (5), and the lower rotor structure comprises a main shaft II (10), the lower ends of the main shaft I (5) and the main shaft II (10) extend into the interior of the fuselage and are mounted on a main shaft bearing seat (11) in the fuselage (44); a motor I (12) and a motor II (13) are provided in the fuselage (44) for respectively controlling the rotation of the main shaft I (5) and the main shaft II (10); the tail rotor (40) is mounted on the motor III (41), and the motor III (41) is mounted on a steering gear (43) at the tail of the fuselage (44); a conductive slip ring (20) is provided in the fuselage, and a rotor of the conductive slip ring (20) is fixed to the lower part of the fuselage (44); a rectangular support frame assembly is provided on the base (32), and a support column (23) movable up and down is provided on the rectangular support frame assembly, and a stator of the conductive slip ring (20) is mounted on the upper end of the support column (23); A photoelectric encoder (21) is fixed to the lower part of the fuselage; The rectangular support frame assembly comprises an upper fixed beam (24), a lower fixed beam (31), a movable beam (28) and two left and right guide light rods (25); the upper and lower ends of the guide light rod 25 are respectively connected to the upper fixed beam (24) and the lower fixed beam (31); the movable beam (28) can move up and down along the guide light rod (25), and the two ends of the movable beam (28) are respectively connected to the two guide light rods (25) through linear bearings (27); a central hole penetrating from top to bottom is provided at the center of the upper fixed beam (24); the lower fixed beam (31) is connected to the base (32); A multi-component force sensor (26) is fixed on the upper side of the movable crossbeam (28), and a transition pressure head (29) is fixed on the lower side of the movable crossbeam (28); a lift sensor (30) is fixed on the upper side of the lower fixed crossbeam (31); the movable crossbeam (28) presses on the lift sensor (30) through the transition pressure head (29); a torque sensor (22) is fixedly connected to the upper end of the support column (23), the torque sensor (22) is fixedly connected to the stator of the conductive slip ring (20), and the lower end of the support column (23) passes through the center hole and is fixedly connected to the multi-component force sensor (26); The motor III (41) is mounted on a steering gear (43) at the tail of a fuselage (44) via a bracket (42), and a thrust sensor is provided on the bracket (42); The upper rotor structure further comprises a hub I (1), a pair of rotors I (2), a plurality of adjustment rods I (3) and an adjustment disk I (4); the rotor I (2) is mounted on the hub I (1), the adjustment disk I (4) is arranged below the hub I (1) and parallel to the hub I (1), the hub I (1) and the adjustment disk I (4) are connected via the adjustment rods I (3); the hub I (1) and the adjustment disk I (4) are fixed on the main shaft I (5); the lower rotor structure further comprises a rotor A hub II (6), a pair of rotor blades II (7), an adjusting rod II (8), an adjusting disk II (9), and a main shaft II (10); the rotor blade II (7) is mounted on the hub II (6); the adjusting disk II (9) is arranged below the hub II (6) and parallel to the hub II (6); the hub II (6) and the adjusting disk II (9) are connected via the adjusting rod II (8); the hub II (6) and the adjusting disk II (9) are fixed on the main shaft II (10); The main shaft I 5 and the main shaft II 10 are located on the same axis, the main shaft II 10 is a hollow shaft, and the main shaft I 5 passes through the main shaft II 10; a synchronous gear pinion I (14) is mounted on the rotating shaft of the motor I (12), a synchronous gear wheel I (16) is mounted on the lower end of the main shaft I (5), and the synchronous gear pinion I (14) and the synchronous gear wheel I (16) are connected via a synchronous toothed belt I (15); a synchronous gear pinion II (17) is mounted on the rotating shaft of the motor II (13), a synchronous gear wheel II (18) is mounted on the lower end of the main shaft II (10), and the synchronous gear pinion II (17) and the synchronous gear wheel II (18) are connected via a synchronous toothed belt II (19).

2. The angular momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter according to claim 1 is characterized in that: A rotor motor driver (36), a tail rotor motor driver (38) and a steering gear driver (39) are provided in the fuselage; the rotor motor driver (36) is used to control the operation of the motor I (12) and the motor II (13); the tail rotor motor driver (38) is used to control the operation of the motor III (41); and the steering gear driver (39) is used to control the operation of the steering gear (43).

3. The angular momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter according to claim 2 is characterized in that: A wireless controller (37) is provided in the fuselage (44); control lines of the rotor motor driver (36), the tail rotor motor driver (38), and the steering gear driver (39) are all connected to the wireless controller (37); and the wireless controller (37) is connected to the main control computer (35) via a wireless network; The power supplies of the rotor motor driver (36), the tail rotor motor driver (38), the steering gear driver (39), and the wireless controller (37) are all provided through the conductive slip ring (20); A wireless main control box (33) is provided on the base (32); the photoelectric signal line of the photoelectric encoder (21), the signal line of the torque sensor (22), the signal line of the lift sensor (30), the signal line of the multi-component force sensor (26) and the power line of the stator of the conductive slip ring (20) are all connected to the wireless main control box (33), and the wireless main control box (33) is connected to a 220V power line (34).

4. The angular momentum conservation demonstration experimental device based on the principle of a twin-rotor helicopter according to claim 1 is characterized in that: The base (32) is a tripod base, and three adjustable support legs (45) are installed below the tripod base. Rollers are installed at the lower ends of the adjustable support legs (45).

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