A transmission system for automatic weapon parts impact fatigue test

Abstract

The application discloses a transmission system for impact fatigue test of automatic weapon parts, which drives the cam rotation by a power source to push the push rod assembly inside the push rod, so that the push rod impacts the piston rod, and then the tested automatic weapon moves and is basically consistent with the live ammunition shooting working condition. The system is composed of a support, a push rod assembly, a cam, a shaft sleeve, a bearing, a bearing cover plate and a cam shaft; the cam is a disc-shaped cam with the motion form of push stroke-far rest-return stroke-near rest, the push stroke motion curve change distance is consistent with the recoil stroke of the piston rod of the tested automatic weapon under the live ammunition shooting working condition; the motion law of the cam return stroke period is the terminal velocity motion law, and the motion type is the cycloid, so that the push rod assembly stably returns to the initial position; the cam, the shaft sleeve, the bearing, the bearing cover plate, the cam shaft and the push rod assembly are installed on the support; the application can simulate the impact fatigue life test of the main parts of the automatic weapon.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of automatic weapon test design, in particular to a transmission system for simulating the impact fatigue life test of the main parts of a gas-operated automatic weapon. BACKGROUND

[0002] During the test and development stage and the actual use process of an automatic weapon, many problems are often exposed, so researchers need to improve and optimize according to the relevant problem data reflected by the automatic weapon. A gas-operated automatic weapon is provided with a gas guiding device, which functions to push the piston with the propellant gas guided from the side hole of the barrel to ensure that the movable parts complete the automatic action. In this movement process, the propellant gas pushes the piston rod, and then drives all the movable parts to move. Since the propellant gas pressure is a dynamic quantity, it has the characteristics of high load intensity and short action time, which leads to mutual collision of the movable parts during the movement process, and inevitably generates a large impact load, affecting the strength and life of the key parts, and further leading to the failure of the entire gun to meet the life requirement.

[0003] At present, the impact fatigue test of automatic weapon parts is relatively less used in the field of automatic weapons. In the past, the reliability test mostly relied on repeated live firing. During the process of optimizing the structure of the reliability test live firing, it may pose unpredictable dangers to the test personnel. The existing impact fatigue test of automatic weapon parts can only perform impact fatigue test on single or partial parts of the automatic weapon, and the state observation and monitoring of the parts and the collection of related test data are not convenient, and the operation process of the test system is complicated. SUMMARY

[0004] The purpose of the present application is to provide a transmission system for impact fatigue test of automatic weapon parts, so as to realize the impact fatigue life simulation test of the main parts of a gas-operated automatic weapon, verify the impact fatigue performance of the parts, and find the weak points of the parts.

[0005] The technical solution for achieving the purpose of the present application is as follows:

[0006] A transmission system for impact fatigue test of automatic weapon parts, comprising:

[0007] a support, a cam rotatingly supported on the support, the cam being used to drive the push rod in the external push rod assembly to reciprocate and impact the piston rod under the driving of an external driving mechanism, so as to simulate the movement of the automatic mechanism;

[0008] The cam is a push stroke-far rest-return stroke-near rest motion form cam, the push stroke curve change distance is consistent with the recoil stroke of the test automatic weapon piston rod under the live ammunition shooting working condition, the return stroke motion law adopts the terminal velocity and the cycloid motion law combination, so that the push rod assembly returns to the initial position stably, the push stroke tail end is connected with the return stroke head end through an arc, this section is a far rest curve, the return stroke tail end is connected with the push stroke head end through an arc, this section is a near rest curve;

[0009] The cam rotation time is same with the single shot time of the automatic weapon.

[0010] Compared with the prior art, the present application has the following advantages:

[0011] (1) the cam push stroke motion curve of the transmission system adopts the five-term modified constant velocity motion law, the law can better fit the motion law of the test automatic weapon piston rod under the action of the propellant gas, and has good motion characteristics, so as to avoid the rigid or flexible impact with the push rod assembly during the impact fatigue test. The initial recoil kinetic energy applied at the tail end of the push rod assembly can simulate the propellant action, so as to ensure that the automatic mechanism completes the whole automatic cycle, so as to realize the impact fatigue life simulation test of the main parts of the gas guided automatic rifle, and the motion trend of the motion mechanism of the test automatic weapon (such as the maximum speed of the automatic mechanism) and the live ammunition shooting are basically the same, and the working state of the automatic weapon parts is basically the same as the actual shooting;

[0012] (2) the best acceleration angle and deceleration angle of the cam push stroke motion curve adopting the five-term modified constant velocity motion law are determined by the particle swarm optimization algorithm, so as to improve the fitting degree of the push stroke motion law and the actual motion law of the piston rod, and the cam mechanism has good motion characteristics during the impact simulation test.

[0013] (2) the most suitable base circle radius and eccentric distance are obtained by optimizing part of the structure parameters of the cam component through the particle swarm optimization algorithm, so as to reduce the contact stress and the mass of the transmission system, and ensure the structural strength.

[0014] (3) the weight of the cam is reduced by topological optimization of the cam structure, so as to reduce the torque borne by the cam shaft, and reduce the stress generated by high speed impact and push rod assembly impact during work;

[0015] (4) the part of sliding friction between the push rod and the cam is changed into rolling friction by the roller installed at the front end of the push rod assembly, so as to reduce the friction resistance and increase the motion flexibility;

[0016] (5) the relative position between the push rod assembly and the cam is adjusted by screwing the push rod assembly and the support, so as to facilitate the adjustment.

[0017] (6) By fixing all components of the transmission system together on the same support, the influence of vibration transmission caused by the separate clamping and fixing of different components on the test can be eliminated. Attached Figure Description

[0018] Figure 1 This is the overall assembly drawing of the transmission system;

[0019] Figure 2 This is an exploded view of the transmission system;

[0020] Figure 3 This is a schematic diagram of a cam.

[0021] Figure 4 A two-dimensional diagram of the cam;

[0022] Figure 5 This is a schematic diagram of the push rod assembly;

[0023] Figure 6 A schematic diagram of the piston rod and push rod assembly;

[0024] Figure 7 This is a schematic diagram illustrating the motion pattern during the precession phase.

[0025] Figure 8 This is a schematic diagram illustrating the motion pattern during the return journey.

[0026] Figure 9 Schematic diagram of a disc cam mechanism with an offset direct-acting roller follower;

[0027] Figure 10 Here is a flowchart of the particle swarm optimization algorithm;

[0028] Figure 11 To optimize the diagram of the front pressure angle;

[0029] Figure 12 This is a schematic diagram of the optimized pressure angle. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] Combination Figure 1 , Figure 2 This embodiment provides a transmission system for impact fatigue testing of automatic weapon components. The system uses a power source to drive a camshaft, which in turn rotates a cam 3. This rotation pushes a push rod assembly 2, and the push rod 2a inside the push rod assembly 2 strikes a piston rod 8, thus ensuring that the movement of the tested automatic weapon is essentially consistent with the conditions of live-fire shooting. The transmission system consists of a support 1, a push rod assembly 2, a cam 3, a bushing 4, a bearing 5, a bearing cover plate 6, and a camshaft 7.

[0032] The cam 3 is rotatably supported on the support 1 through a shaft sleeve 4, a bearing 5, and a bearing cover plate 6, a cam shaft 7 is used to drive the cam 3 to rotate under an external motor, a push rod assembly 2 is fixed on the support 1, a push rod 2a is arranged in the push rod assembly 2, a return spring 2b is arranged between the push rod 2a and the push rod assembly 2 shell, a piston rod 8 is arranged in the support 1, and the push rod 2a reciprocates and impacts the piston rod 8 under the action of the cam 3 and the return spring 2b.

[0033] The piston rod 8 belongs to a component of the automatic weapon to be tested, and the whole gun structure is not the focus of the patent, so it is not described in detail. The purpose of the design of the patent is to provide a transmission system. Through the transmission mode of the transmission system, an effect that can replace the real shooting working condition is generated, that is, the mechanism designed in the patent continuously impacts the head of the piston rod 8 in the push rod assembly 2 to continuously drive the piston rod 8 to move backward, wherein after the piston rod 8 is impacted to move backward, the piston rod 8 is returned under the action of the return spring 2b to accept the next impact of the mechanism.

[0034] Hereinafter, the direction indicated by the impacted surface of the piston rod 8 is the front end.

[0035] In combination Figure 3 , Figure 4 , the push stroke section 3a of the cam 3 is divided into an acceleration section s1, a constant speed section s2, and a deceleration section s3, which are designed to ensure that the automatic mechanism completes the whole automatic cycle, and the generated effect is basically consistent with the movement trend of each stage of the movement mechanism (such as the maximum speed of the automatic mechanism) of the automatic weapon to be tested and the real bullet shooting; the movement law of the return stroke period 3b of the cam 3 adopts a combination of terminal speed and cycloid movement law, so that the push rod assembly returns to the initial position smoothly. The structure of the cam 3 is topologically optimized, so that it has smaller mass and higher strength.

[0036] In combination Figure 5 , a roller is additionally installed at the front end of the push rod 2a assembly, which converts part of the sliding friction between the push rod 2a and the cam into rolling friction, reduces the friction resistance, and increases the movement flexibility.

[0037] In combination Figure 6 , the rear end surface of the push rod 2a in the push rod assembly 2 cooperates with the front end surface of the piston rod 8, and the shape of the end impact surface is designed to be consistent with the front end surface of the piston rod 8 to reduce stress concentration during impact.

[0038] In combination Figure 1 , the push rod assembly 2 in the device described in the patent is installed on the support 1 through threaded connection to control the distance between the push rod assembly 2 and the cam 3, the cam 3 is installed on the cam shaft 7, and shaft sleeves 4, bearings 5, and bearing cover plates 6 are installed at both ends to ensure normal movement. The rear end of the push rod 2a in the push rod assembly 2 cooperates with the piston rod 8.

[0039] The working process of the mechanism is as follows: firstly, the relative position of the push rod assembly 2 and the cam 3 is adjusted through the threads between the push rod assembly 2 and the support 1, the cam shaft 7 is driven under the driving of the power source, the cam shaft 7 drives the cam 3 to rotate through the spline connection, the cam 3 pushes the push rod assembly 2 to rotate, in this process, the cam 3 is loaded through the push curve 3a, the push rod 2a compresses the return spring 2b to move backward, and collides with the piston rod 8 of the automatic weapon to apply initial kinetic energy, drives the piston rod 8 to recoil, and the loading process is basically consistent with the actual shooting condition of the automatic weapon, thereby completing the subsequent automatic cycle process of the test automatic weapon; when the automatic weapon completes a series of actions such as recoil and shell ejection, it starts to return, the push rod 2a moves forward under the action of the return spring 2b during the return process, returns to the initial position, and waits for the second impact; after the cam push section 3a is completed, the cam experiences the far rest, return and near rest periods to complete one shot, and the length of one rotation of the cam is the same as the length of single shot of the automatic weapon.

[0040] The cam 3 is a disc-shaped cam with the motion form of push - far rest - return - near rest. By designing the curves of each stage of the cam, the cam motion can drive the push rod assembly 2 to make the automatic action of the automatic weapon basically consistent with the automatic action under the actual bullet shooting condition; by optimizing the design of the base circle radius and the eccentric distance of the cam 3, the cam can meet the requirements of strength, mass and the like.

[0041] Firstly, the push curve of the cam is designed. The push curve of the cam is designed to make the motion curve of the motion parts (such as the receiver, the head and the like) of the automatic weapon basically consistent with that under the actual bullet shooting condition.

[0042] Firstly, a suitable motion law is selected to be applied to the cam push. The push curve of the cam adopts a five-term modified constant velocity motion law, which can better fit the motion law of the piston rod of the test automatic weapon under the action of the propellant gas, and has good motion characteristics to avoid rigid or flexible impact with the push rod assembly during the impact fatigue test. The push curve of the cam uses one-half of the motion period of the quintic polynomial to replace the initial and final stages of the constant velocity motion law, combines the motion curves to form the motion law of the push period. The motion law can be divided into three sections, i.e. the acceleration section s1, the constant velocity section s2 and the deceleration section s3. The displacement expression of the follower in the push period is:

[0043]

[0044] In the formula, h1, h2 and h are respectively the stroke of the acceleration section, the stroke of the deceleration section and the total stroke; φ1, φ2 and φ are respectively the acceleration angle, the deceleration angle and the total push angle; The angle independent variables of the push acceleration section, the constant velocity section and the deceleration section are respectively s1, s2 and s3; wherein s1 in s2 in Wherein φ1, φ2 formula for:

[0045]

[0046] The schematic diagram of the motion law of the push phase is shown in Figure 7 .

[0047] Second, based on the selected quintic correction constant motion law, the improved fast particle swarm optimization algorithm (APSO) is used to optimize the cam push phase acceleration angle φ1 and deceleration angle φ2. From equation (1), when the to-be-determined constant is determined, the push phase acceleration angle φ1 and deceleration angle φ2 affect the fitting degree of the motion law and the actual motion law of the piston rod and the motion characteristics of the cam mechanism in the push phase. Select φ1, φ2 as the optimization design variables, [φ1, φ2] = [x1, x2].

[0048] The displacement-time curve of the test automatic weapon piston rod is converted into a displacement-angle curve, and a reference sample set Y(x) = [y1, y2, y3...y i ...y n ] is formed as the true value. The design variables x1, x2 that meet the constraint condition are brought into the motion law curve equation, and the displacement point set corresponding to the cam profile curve is obtained, denoted as S(x) = [s1, s2, s3...s i ...s n ]. The fitting degree R 2 is taken as the index of the fitting degree of the design curve to the reference sample, and the calculation method is shown in equations (3) and (4).

[0049]

[0050]

[0051] In the formula, SST, SSR, SSE are total sum of squares, regression sum of squares and residual sum of squares respectively; n is the total number of samples; is the mean of the reference sample ordinate; y i is the i-th reference sample ordinate value; s i is the i-th displacement point ordinate value.

[0052] The objective function f1(x) is constructed. The standard deviation between the design curve and the reference curve is required to be as small as possible, so that the fitting degree of the design curve and the reference curve is as high as possible. The objective function f1(x) is:

[0053]

[0054] In the formula, f1(x) is the standard deviation between the design curve and the reference curve.

[0055] At the same time, the velocity deviation is required as the second objective function. Since the motion law of the cam push curve is a five-term modified constant velocity motion curve, the velocity changes in the process of acceleration-constant velocity-deceleration, so the difference between the maximum velocity v0 of the cam push curve and the reference curve is considered to construct the objective function. Then,

[0056]

[0057]

[0058] In the formula, is the angle independent variable of the acceleration segment; f2(x) is the maximum velocity of the cam push curve and the difference between the maximum velocity v0 of the reference curve.

[0059] Set the remaining related constraints:

[0060]

[0061] In the formula, X max is the maximum value of the sum of the acceleration angle φ1 and the deceleration angle φ2, x max is the maximum value of the acceleration angle φ1 and the deceleration angle φ2.

[0062] The unified objective function form can be expressed as:

[0063] min F1(x)=w1f1(x)+w2f2(x) (9)

[0064] In the formula, F1(x) is the objective function of the acceleration angle and deceleration angle optimization model, and w1 and w2 are the weighting coefficients of the sub-target.

[0065] Thus, the optimal values of the acceleration angle φ1 and the deceleration angle φ2 can be obtained.

[0066] After the cam push curve is designed, the cam return curve is designed, which satisfies the requirement of making the push rod assembly return to the initial position smoothly.

[0067] First, select a suitable motion law for the cam return. The return motion curve adopts a combination of terminal velocity and cycloid motion law, which can make the push rod assembly return to the initial position smoothly and avoid impact during the return process.

[0068] The displacement s4 and velocity v1 of the terminal velocity segment are:

[0069] v1=C (10)

[0070]

[0071] The displacement s5 of the cycloid segment is:​

[0072]

[0073] where v1 is the terminal velocity, C is a constant, h4, h5, h' are the terminal velocity start offset point, the terminal velocity end offset point and the total return stroke respectively, and h' = h; φ3, φ4, φ' are the terminal velocity start angle, the terminal velocity end angle and the total return stroke angle respectively; are the angle independent variables of the terminal velocity segment and the cycloid segment respectively; where in s4 in s5

[0074] Secondly, based on the above displacement formula and the requirements of the automatic weapon's action, the values of the terminal velocity start angle φ3 and the terminal velocity end angle φ4 are determined by taking the cam return stroke curve and the pressure angle between the push rod as the main parameters, which can ensure that the pressure angle of the return stroke segment is small. Since the cam return stroke motion curve design does not need to be strictly the same as the automatic weapon's action curve, only the stable reset of the push rod assembly is required, therefore, the particle swarm optimization algorithm is not used to optimize the values.

[0075] The motion law of the return stroke period is shown in Figure 8 .

[0076] After the cam push stroke and return stroke curves are designed, the push stroke curve and the return stroke curve are connected at both ends. The tail end of the push stroke is connected to the head end of the return stroke through a circular arc, which is a far rest curve, and the radius is R 远 , and the corresponding circular arc angle is φ 远 ; the tail end of the return stroke is connected to the head end of the push stroke through a circular arc, which is a near rest curve, and the radius is R 近 = r b , and the corresponding circular arc angle is φ 近 , where r b is the base circle radius.

[0077] After the curves of each stage of the cam are designed, in order to ensure that the transmission structure of the impact simulation test system has good transmission performance, the structure parameters of the cam need to be further designed and optimized. In this case, the pressure angle and the base circle radius of the cam are mainly designed and optimized. By limiting the pressure angle, the transmission performance of the mechanism can be optimized; by optimizing the design to minimize the base circle radius, the mass of the cam component can be reduced, and the load and torque of the driving motor can be reduced.

[0078] As shown in Figure 9 , the pressure angle and the base circle radius of the cam are mainly determined by the distance y of the roller center to the x-axis in the vertical direction and the eccentricity e on the base circle, therefore, the first step is to select the design variables:

[0079] x = [x3, x4] = [y, e] (13)

[0080] Base circle radius r b is:

[0081]

[0082] Second step, the constraint function is established.

[0083] (1) The curvature radius constraint. To avoid motion distortion, the minimum curvature radius is constrained, and the constraint condition is established:

[0084]

[0085] R K = R B -r T (16)

[0086] In the formula, v is the vertical speed of the follower, s is the vertical distance from the roller center to the base circle on the theoretical profile curve, R B is the theoretical curvature radius, R K is the curvature radius of the contact point on the actual profile of the cam, r T is the roller radius, η is the correction coefficient, η takes ±1, and the remaining parameters are shown in Figure 9 .

[0087] (2) The constraint condition is established by the cam contact stress condition σ Hmax ≤ [σ H ], where [σ H ] is the allowable stress.

[0088] The maximum contact stress between the cam and the roller is:

[0089]

[0090] In the formula, R f is the curvature radius of the contact point on the follower; ν c and ν f are the Poisson's ratios of the cam and the follower roller respectively; E c and E f are the elastic moduli of the cam and the follower roller respectively; g is the contact width of the cam and the follower (usually the thickness of the cam); F N is the normal pressure of the cam pair.

[0091] (3) Base circle radius constraint, in order to ensure that the cam has sufficient structural strength to meet r b ≥ [r b ], the constraint condition is established.

[0092] For steel cams, the allowable radius is:

[0093] [r b ]=1.75r b +r T +6 (18)

[0094] (4) Cam pressure angle constraint:

[0095]

[0096] (5) Set the rest of the relevant constraints:

[0097]

[0098] In the formula, x' max is the maximum value of the parameter y, and x" max is the maximum value of the eccentricity e.

[0099] Third, establish constraint targets.

[0100] Minimize the cam pressure angle as the constraint target.

[0101] min f3(x)=max[α1,α2,α3…α i …α n ] (21)

[0102] In the formula, α i is the i-th pressure angle value, and f3(x) is the minimum cam pressure angle.

[0103] Minimize the base circle radius as the constraint target.

[0104]

[0105] In the formula, f4(x) is the minimum base circle radius of the cam.

[0106] The unified target function form can be expressed as:

[0107] min F2(x)=w3f3(x)+w4f4(x) (23)

[0108] In the formula, F2(x) is the base circle radius and pressure angle optimization model target function, and w3, w4 are the weighting coefficients of the sub-target.

[0109] Fourth, based on the above constraint functions and constraint targets, the particle swarm algorithm is used for calculation.

[0110] The optimization design of power transmission mechanism mainly optimizes the base circle radius and eccentricity of cam. Among many design values, the best set of design parameters is found to make the cam component better achieve the expected motion law in the process of impact simulation test and have good dynamic characteristics. The particle swarm algorithm has good universality, simple rules and is suitable for processing various types of objective functions and constraints. The basic flow of the algorithm is shown in Figure 10 .

[0111] From Figure 10 It can be seen that when the particle swarm algorithm is calculated, a group of particles is initialized to start from a random solution, and the optimal solution and fitness are found by updating iteration. In the process of each updating iteration, the particle updates itself by searching the optimal solution and individual extreme value and group extreme value found by the individual and the whole particle swarm, and the speed and individual position expression are:

[0112] v is (t+1) = ωv is (t) + c1r 1s (p is (t) - x is (t)) + c2r 2s (p gs (t) - x gs (t)) (24)

[0113] x is (t+1) = x is (t) + v is (t+1) (25)

[0114] In the formula, ω is the inertia weight; v is (t+1) represents the speed of the particle at t+1; v is (t) represents the speed of the particle at t; x is (t+1) represents the position of the particle at t+1; x is (t) represents the position of the particle at t; x gs (t) represents the position of the whole particle swarm at t; c1 and c2 are learning factors; r 1s and r 2s represent the uniform distribution of random numbers on [0,1]; i = [1, m], m is the number of particles; s = [1, S], S is the space dimension; p is (t) represents the optimal position searched by the particle at t; p gs (t) represents the optimal position searched by the whole particle swarm at t.

[0115] The particle swarm optimization algorithm is used to design and optimize the structural parameters of the cam component, the optimal position searched by the entire particle swarm is determined, the corresponding optimal y and e are obtained, and then the optimized base circle radius and pressure angle are obtained. The schematic diagram of the pressure angle before optimization is shown in Figure 11 , and the schematic diagram of the pressure angle after optimization is shown in Figure 12 .

Claims

1. A drive system for automatic weapon component impact fatigue testing, characterized by, Comprise: A support, a cam rotatingly supported on the support, the cam being configured to reciprocate a push rod in an external push rod assembly under driving of an external driving mechanism to impact a piston rod to simulate a movement of an automatic machine; The cam is a push stroke-far rest-return stroke-near rest movement form cam, a push stroke change is used to simulate a propellant gas pushing, a push stroke curve change distance is consistent with a recoil stroke of the piston rod of the automatic weapon under a live ammunition shooting working condition; a return stroke movement law is combined with a terminal velocity and a cycloid movement law to make the push rod assembly stably return to an initial position; A push stroke tail end is connected with a return stroke head end through an arc, and this section is a far rest curve; a return stroke tail end is connected with a push stroke head end through an arc, and this section is a near rest curve; A cam rotation time is same as a single shot time of the automatic weapon; The push stroke section is composed of an acceleration section s1, a constant speed section s2 and a deceleration section s3, and meets: wherein: In the formula: h1, h2, h are the stroke of acceleration section, deceleration section and total stroke respectively; φ1, φ2, φ are the acceleration angle, deceleration angle and total angle of stroke respectively; are the angle independent variables of the acceleration section, constant speed section and deceleration section of the stroke respectively; wherein Optimization design is performed on a push stroke acceleration angle φ1 and a deceleration angle φ2 of the cam push stroke period: φ1, φ2 are selected as optimization design variables, and [φ1, φ2] is defined as [x1, x2]; The displacement-time curve of the automatic weapon piston rod of the subject is converted into a displacement-angle curve to form a reference sample point set Y(x) = [y1, y2, y3...y i ...y n ] as a true value. The design variables x1 and x2 that satisfy the constraint condition are brought into the motion law curve equation to obtain a displacement point set corresponding to the cam profile curve, denoted as S(x) = [s1, s2, s3...s i ...s n ]. The goodness of fit R 2 As an index of the goodness of fit of the design curve to the reference points, a target function f1(x) and f2(x) are constructed, a unified target function minF1(x)=w1f1(x)+w2f2(x) is set, a constraint is set, and the optimal values of the acceleration angle φ1 and the deceleration angle φ2 are obtained. Wherein, w1, w2 are weighting coefficients of f1(x) and f2(x) respectively, f1(x) is the standard deviation between the design curve and the reference curve, f2(x) is the difference between the maximum speed v of the cam push and the maximum speed v0 on the reference curve x1 of the cam push and the maximum speed v0 on the reference curve The objective function f1(x) is: The objective function f2(x) is: min f2(x) = v x1 - v0; Constraints are set: wherein: X max x is the maximum value of the acceleration angle φ1 and the deceleration angle φ2 and max x is the maximum value of the acceleration angle φ1 and the deceleration angle φ2 and 2. The drive system for automatic weapon part impact fatigue testing of claim 1, wherein, A displacement s4 and a velocity v1 of the terminal velocity section of the return stroke section are: v1=C A displacement s5 of the cycloid section is: In the formula, C is a constant, h4, h5, h' are respectively the terminal velocity start offset point, the terminal velocity end offset point and the total return stroke; φ3, φ4, φ' are respectively the terminal velocity start angle, the terminal velocity end angle and the total return stroke angle; are respectively the angle independent variables of the terminal velocity section and the cycloid section; wherein 3. The drive system for automatic weapon part impact fatigue testing of claim 2, wherein, The cam base circle radius is minimized through optimization design to reduce the cam mass: Design variables are selected as x and e, and x=[x3, x4]=[y, e] Wherein y and e are respectively a distance of a push rod roller center to an x axis in a vertical direction and an eccentricity on the base circle; A constraint function is established: A maximum contact stress between the cam and the roller is: R K = R B -r T where v is the speed of the follower in the perpendicular direction, s is the perpendicular distance from the center of the roller to the base circle on the theoretical profile curve, R B is the theoretical radius of curvature, R K is the radius of curvature of the contact point on the actual profile of the cam, r T is the roller radius, and η is a correction factor. Cam contact stress condition: σ Hmax ≤ [σ H ]; [σ H ] is the allowable stress; A unified target function form can be expressed as: where R f is the radius of curvature of the contact point on the follower; v c and v f are the material Poisson's ratios of the cam and follower rollers, respectively; E c and E f are the material elastic moduli of the cam and follower rollers, respectively; g is the contact width of the cam with the follower; F N is the normal force of the cam pair; Base circle radius constraint: r b ≥ [r b ]; r b is the base circle radius; Allowable radius: [r b ] = 1.75r b + r T + 6; Cam pressure angle constraint: The remaining relevant constraints: where x' is the maximum value of the parameter y, x" max is the maximum value of the parameter y, x" max is the maximum value of the eccentricity e; Minimize cam pressure angle as a constraint objective: min f3(x) = max [a1, a2, a3... a i ... a n ] Minimizing the base circle radius as a constraint target: minF2(x)=w3f3(x)+w4f4(x) Based on the above constraint functions and constraint targets, particle swarm optimization algorithm is used to design and optimize the structure parameters of the cam component, an optimal position searched by the whole particle swarm is determined, corresponding optimal y and e are obtained, and then an optimized base circle radius and a pressure angle are obtained. In the formula, F2(x) is a base circle radius, pressure angle optimization model objective function, w3, w4 are respectively weighted coefficients of f3(x) and f4(x); α i is the i-th pressure angle value, f3(x) is the minimum pressure angle of the cam, and f4(x) is the minimum base circle radius of the cam. The push rod assembly and the base are connected through threads.

4. The drive system for automatic weapon part impact fatigue testing of claim 1, wherein, ​

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