Variable-frequency drop hammer impact testing machine and automatic cycle control method thereof

Abstract

The invention provides a variable-frequency drop hammer impact testing machine. An electrical part of the variable-frequency drop hammer impact testing machine comprises a first proximity switch, a second proximity switch, a third proximity switch, a fourth proximity switch, an automatic / manual selection switch, a lifting button, a lowering button, a stop button, a programmable controller, a frequency converter and a pneumatic electromagnetic directional valve, the first proximity switch, the second proximity switch, the third proximity switch, the fourth proximity switch, the automatic / manual selection switch, the lifting button, the lowering button and the stop button are respectively connected with X0-X7 input pins of the programmable controller; output pins Y0-Y5 of the programmable controller are correspondingly connected with a forward rotation pin, a reverse rotation pin, a starting pin, a first constant speed pin and a second constant speed pin of the frequency converter and the pneumatic electromagnetic reversing valve respectively; the first proximity switch, the second proximity switch, the third proximity switch and the fourth proximity switch are sequentially arranged on the testing machine from top to bottom.

Description

Technical Field

[0001] The present disclosure relates to the field of automated product control methods, and in particular to a variable frequency drop hammer impact testing machine and an automatic cycle control method thereof. Background Art

[0002] A drop hammer impact tester is a material mechanics testing device that uses a drop hammer to impact a test piece. It is used to evaluate the bending strength, fatigue characteristics, fracture toughness and other properties of the test piece under impact load. It is widely used in various industries and can be divided into two types: single impact and continuous impact. For continuous impact testing machines, the number of impacts is often large, even thousands of times. Even if each test cycle is shortened by 1 second, the saving of the entire test time is considerable. Therefore, in order to improve efficiency, the running time of a test cycle is minimized as much as possible while meeting the safety, component and mechanism limit capacity range. The single running cycle of the existing impact testing machines on the market is often a rough estimate during the design, without rigorous calculation, so the single running cycle is generally not optimal. Summary of the invention

[0003] In response to the above technical problems in the related art, the present disclosure proposes a variable frequency drop hammer impact testing machine that can screen out products within the required power range before installation and has fast response, no overshoot and high precision, which can overcome the above shortcomings of the prior art.

[0004] To achieve the above technical objectives, the technical solution of the present disclosure is implemented as follows: The first object of the present disclosure is to provide a variable frequency drop weight impact testing machine, comprising a mechanical part and an electrical part that cooperate with each other, wherein the mechanical part comprises a reduction motor, a guide wheel, a steel wire rope, a base, a channel steel column, a drop weight, two cylindrical guide rails, a grabbing mechanism, a top plate, a chain, a sprocket set, a wedge mechanism, a cylinder mounting plate, a first cylinder, and a second cylinder; The first cylinder and the second cylinder are symmetrically arranged on the left and right sides of the base, and the cylinder bodies of the first cylinder and the second cylinder are respectively fixedly connected to the channel steel column through the cylinder mounting plate; The reduction motor is arranged inside the base, the output shaft of the reduction motor is connected with the guide wheel key, one end of the steel wire rope is fixed and wound around the guide wheel, and the other end of the steel wire rope passes through the inside of the channel steel column from bottom to top and is connected with one end of the chain; The top plate is arranged on the top of the mechanical part, the sprocket set is arranged on the top of the top plate, and the other end of the chain is hung downward on the top of the grabbing mechanism after passing through the sprocket set; The drop hammer is located directly below the grabbing mechanism, and a ball head is provided on the top of the drop hammer that can be inserted into the grabbing mechanism and reliably connected thereto; the two cylindrical guide rails are located between the base and the top plate in the longitudinal direction, and the two cylindrical guide rails are located on the left and right sides of the base in the transverse direction, and the drop hammer and the grabbing mechanism can be slidably connected to the two cylindrical guide rails respectively; The electrical part includes the first proximity switch, the second proximity switch, the third proximity switch, the fourth proximity switch, the automatic / manual selection switch, the lifting button, the lowering button, the stop button, the programmable controller, the frequency converter, and the pneumatic electromagnetic reversing valve; The first proximity switch, the second proximity switch, the third proximity switch, the fourth proximity switch, the automatic / manual selection switch, the lifting button, the lowering button, and the stop button are respectively connected to the X0--X7 input pins of the programmable controller; The Y0-Y5 output pins of the programmable controller are respectively connected to the forward, reverse, start, first constant speed, second constant speed pins of the frequency converter and the pneumatic electromagnetic reversing valve; The first proximity switch, the second proximity switch, the third proximity switch, and the fourth proximity switch are sequentially arranged on the testing machine from top to bottom.

[0005] Preferably, the first proximity switch, the second proximity switch, the third proximity switch and the fourth proximity switch are arranged on the channel steel column in sequence from top to bottom.

[0006] Preferably, the grabbing mechanism is provided with a connection socket for inserting the ball head. During implementation, when the drop hammer and the grabbing mechanism slide to the point where they can dock, the ball head is inserted upward into the connection socket, thereby completing the reliable connection of the drop hammer and the grabbing mechanism.

[0007] Preferably, the first cylinder and the second cylinder are high-speed cylinders with the same specifications.

[0008] Preferably, the fourth proximity switch is an omnipolar Hall proximity switch.

[0009] Preferably, the frequency converter is provided with a deceleration ramp parameter T ud , deceleration ramp parameter T dd ; n dmax The speed of the reduction motor corresponding to the maximum linear speed during lowering; n umax The speed of the reduction motor corresponding to the maximum linear speed during lifting; The maximum vertical movement stroke of the grabbing mechanism is H; The equivalent diameter of the guide wheel after the steel wire rope is wound is d; The reduction ratio of the reduction motor is i.

[0010] Preferably, when the gripping mechanism slides until the wedge-shaped mechanism is fully inserted therein, the first proximity switch is flush with the upper plane of the gripping mechanism; The distance between the second proximity switch and the first proximity switch is ; The distance between the third proximity switch and the first proximity switch is .

[0011] Preferably, the fourth proximity switch is located between the upper plane at the initial position of the drop hammer and the third proximity switch; an opening is provided on the side of the drop hammer facing the fourth proximity switch, a permanent magnet is provided in the opening, and the length of the permanent magnet is consistent with the depth of the opening.

[0012] Preferably, when the grabbing mechanism is connected and drives the drop weight to move up and down, the first proximity switch, the second proximity switch and the third proximity switch can all sense the grabbing mechanism, and the fourth proximity switch can thereby sense the permanent magnet.

[0013] Preferably, the acceleration ramp parameter T of the frequency converter is ua Determined by formula 1 as the initial setting value: (Formula 1); Wherein, m is the total mass of the grabbing mechanism and the drop weight; n umax The speed of the reduction motor corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor; η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time that can be set for the inverter.

[0014] Preferably, the deceleration ramp parameter T of the frequency converter is ud Determined by formula 2 as the initial setting value: (Formula 2); Among them, n umax The speed of the reduction motor corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor; g is the acceleration due to gravity; T min The minimum ramp time that can be set for the inverter.

[0015] Preferably, the acceleration ramp parameter T of the frequency converter is da Determined by formula 3 as the initial setting value: (Formula 3); Among them, n dmax The speed of the reduction motor corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor; g is the acceleration due to gravity; T min The minimum ramp time that can be set for the inverter.

[0016] Preferably, the deceleration ramp parameter T of the frequency converter is dd Determined by formula 4 as the initial setting value: (Formula 4); Where m is the total mass of the grabbing mechanism and the drop weight; n dmax The speed of the reduction motor corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor; η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time that can be set for the inverter.

[0017] The second object of the present disclosure is to provide an automatic cycle control method for the variable frequency drop weight impact testing machine, comprising the following steps: S1: Initialization, setting the value of the automatic cycle number N, and clearing the counters C0 and C1 inside the programmable controller to 0; S2: When there is no signal at the input pin X4 of the programmable controller, it is in automatic cycle control mode, and only the output pin Y5 outputs a signal, and the first cylinder and the second cylinder are lifted; S3: When there is a signal on the input pin X5 of the programmable controller, only the output pins Y0, Y2, Y3, and Y5 output signals, and the grabbing mechanism is lifted at the first constant speed setting value, and the delay starts at the same time; S4: After a delay of 0.5 seconds, when there is no signal at the input pin X3 of the programmable controller, it indicates that the grasping mechanism grasps successfully, and only the output pins Y0, Y2, Y3, and Y5 output signals, while C1 is cleared to 0, and the process goes to S6; when there is a signal at the input pin X3 of the programmable controller, it indicates that the grasping mechanism fails to grasp, C1 counts once, and the process goes to S5; S5: If C1>3, continue to S6; otherwise, if C1<3, go to S2; otherwise, if C1=3, go to S8; S6: When there is a signal at the input pin X1 of the programmable controller, only the output pins Y0, Y2, Y3, and Y4 output signals, and the grabbing mechanism decelerates and lifts to a stop; S7: When there is a signal on the input pin X0 of the programmable logic controller, C0 counts once, and at the same time, the delay starts; S8: When the delay seconds later, only the output pins Y1, Y2, Y4, and Y5 output signals, and the grasping mechanism lowers at the second constant speed setting value; S9: When there is a signal on the input pin X2 of the programmable logic controller, only the output pins Y1, Y2, Y3, Y4, and Y5 output signals, the grasping mechanism decelerates and lowers to a stop, and at the same time, the first cylinder and the second cylinder lift up; S10: If C0 < N, return to S3; if C0 = N, end the operation.

[0018] Preferably, the first constant speed setting value is n umax , and the second constant speed setting value is n dmax ; When there are signals on both the first constant speed and the second constant speed pins, the first constant speed setting value is n umax , and the second constant speed setting value is n dmax are both set to 0; g is the acceleration due to gravity, and N is the number of automatically set cycles by the user.

[0019] Preferably, N is determined according to actual needs, and is preferably 5 - 20 times.

[0020] Compared with the prior art, the present disclosure has the following beneficial effects: (1) For the proximity switch installation position parameters of the variable frequency drop hammer impact testing machine of the present disclosure, there are calculation formulas for reference, avoiding the randomness of its installation.

[0021] (2) For the variable frequency drive acceleration and deceleration ramp parameters of the variable frequency drop hammer impact testing machine of the present disclosure, there are calculation formulas for reference, avoiding the blindness in configuring such parameters.

[0022] (3) The automatic cycle control method of the variable frequency drop hammer impact testing machine of the present disclosure can realize the automatic continuous periodic operation of the testing machine, with a short single cycle period, greatly improving the efficiency of the testing machine.

[0023] (4) The automatic cycle control method of the variable frequency drop hammer impact testing machine of the present disclosure has a detection function for unsuccessful grasping of the drop hammer. If the grasping is unsuccessful three times in a row, the machine can automatically stop. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a structural schematic diagram of the variable frequency drop weight impact testing machine described in the present invention.

[0026] Figure 2 This is a diagram of the programmable controller peripheral interface of the electrical part described in the present disclosure.

[0027] In the figure: 1. reduction motor; 2. guide wheel; 3. wire rope; 4. base; 5. channel steel column; 6. drop weight; 601, ball head; 7. fourth proximity switch; 8. third proximity switch; 9. cylindrical guide rail; 10. second proximity switch; 11. grabbing mechanism; 1101, connecting socket; 12. first proximity switch; 13. top plate; 14. chain; 15. sprocket; 16. wedge mechanism; 17. cylinder mounting plate; 18. first cylinder; 19. second cylinder; 20. automatic / manual selection switch; 21. lifting button; 22. lowering button; 23. stop button; 24. programmable controller; 25. frequency converter; 26. pneumatic electromagnetic reversing valve. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0029] like Figure 1-2 As shown, in order to facilitate the understanding of the above technical solutions of the present disclosure, the above technical solutions of the present disclosure are described in detail below through specific usage methods.

[0030] The first object of the present disclosure is to provide a variable frequency drop weight impact testing machine, comprising a mechanical part and an electrical part that cooperate with each other, wherein the mechanical part comprises a reduction motor 1, a guide wheel 2, a steel wire rope 3, a base 4, a channel steel column 5, a drop weight 6, two cylindrical guide rails 9, a grabbing mechanism 11, a top plate 13, a chain 14, a sprocket set 15, a wedge mechanism 16, a cylinder mounting plate 17, a first cylinder 18, and a second cylinder 19; The first cylinder 18 and the second cylinder 19 are symmetrically arranged on the left and right sides of the base 4, and the cylinder bodies of the first cylinder 18 and the second cylinder 19 are fixedly connected to the channel steel column 5 through the cylinder mounting plate 17 respectively; The reduction motor 1 is arranged inside the base 4, the output shaft of the reduction motor 1 is key-connected with the guide wheel 2, one end of the wire rope 3 is fixed and wound around the guide wheel 2, and the other end of the wire rope 3 passes through the inside of the channel steel column 5 from bottom to top and is connected to one end of the chain 14; The top plate 13 is arranged on the top of the mechanical part, the sprocket set 15 is arranged on the top of the top plate 13, and the other end of the chain 14 is hung downward on the top of the grabbing mechanism 11 after passing through the sprocket set 15; The drop hammer 6 is located directly below the grabbing mechanism 11, and a ball head 601 is provided on the top of the drop hammer 6, which can be inserted into the grabbing mechanism 11 and reliably connected thereto; the two cylindrical guide rails 9 are located between the base 4 and the top plate 13 in the longitudinal direction, and the two cylindrical guide rails 9 are located on the left and right sides of the base 4 in the transverse direction, respectively, and the drop hammer 6 and the grabbing mechanism 11 can be slidably connected to the two cylindrical guide rails 9 respectively; The electrical part includes a first proximity switch 12, a second proximity switch 10, a third proximity switch 8, a fourth proximity switch 7, an automatic / manual selection switch 20, a lifting button 21, a lowering button 22, a stop button 23, a programmable controller 24, a frequency converter 25, and a pneumatic electromagnetic reversing valve 26; The first proximity switch 12, the second proximity switch 10, the third proximity switch 8, the fourth proximity switch 7, the automatic / manual selection switch 20, the lifting button 21, the lowering button 22, and the stop button 23 are respectively connected to the X0--X7 input pins of the programmable controller 24; The Y0--Y5 output pins of the programmable controller 24 are respectively connected to the forward rotation, reverse rotation, start, first constant speed, second constant speed pins of the frequency converter 25 and the pneumatic electromagnetic reversing valve 26; The first proximity switch 12 , the second proximity switch 10 , the third proximity switch 8 , and the fourth proximity switch 7 are sequentially arranged on the testing machine from top to bottom.

[0031] In one embodiment, the first proximity switch 12 , the second proximity switch 10 , the third proximity switch 8 , and the fourth proximity switch 7 are sequentially arranged on the channel steel column 5 from top to bottom.

[0032] In one embodiment, the grabbing mechanism 11 is provided with a connection socket 1101 for inserting the ball head 601. In implementation, when the drop hammer 6 and the grabbing mechanism 11 slide to be able to dock, the ball head 601 is inserted upward into the connection socket 1101, thereby completing the reliable connection between the drop hammer 6 and the grabbing mechanism 11.

[0033] In one embodiment, the first cylinder 18 and the second cylinder 19 are preferably high-speed cylinders with the same specifications.

[0034] In one embodiment, the fourth proximity switch 7 is preferably an omnipolar Hall proximity switch.

[0035] In one embodiment, the frequency converter 25 is provided with a deceleration ramp parameter T ud , deceleration ramp parameter T dd ; n dmax is the speed of the reduction motor 1 corresponding to the maximum linear speed during lowering; n umax is the speed of the reduction motor 1 corresponding to the maximum linear speed during lifting; The maximum vertical movement stroke of the grabbing mechanism 11 is H; The equivalent diameter of the guide wheel 2 after being wound with the wire rope 3 is d; The reduction ratio of the reduction motor 1 is i.

[0036] In one embodiment, when the gripping mechanism 11 slides until the wedge-shaped mechanism 16 is fully inserted therein, the first proximity switch 12 is flush with the upper plane of the gripping mechanism 11; The distance between the second proximity switch 10 and the first proximity switch 12 is ; The distance between the third proximity switch 8 and the first proximity switch 12 is .

[0037] In a certain embodiment, the fourth proximity switch 7 is located between the upper plane of the drop hammer 6 at the initial position and the third proximity switch 8; an opening is provided on the side of the drop hammer 6 facing the fourth proximity switch 7, and a permanent magnet is provided in the opening, and the length of the permanent magnet is consistent with the depth of the opening.

[0038] In one embodiment, when the grabbing mechanism 11 is connected and drives the drop weight 6 to move up and down, the first proximity switch 12, the second proximity switch 10, and the third proximity switch 8 can all sense the grabbing mechanism 11, and the fourth proximity switch 7 can thereby sense the permanent magnet.

[0039] In one embodiment, the acceleration ramp parameter T of the inverter 25 is ua Determined by formula 1 as the initial setting value: (Formula 1); Wherein, m is the total mass of the grabbing mechanism 11 and the drop weight 6; n umax The speed of the reduction motor 1 corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor 1; η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time that can be set for frequency converter 25.

[0040] In one embodiment, the deceleration ramp parameter T of the inverter 25 is ud Determined by formula 2 as the initial setting value: (Formula 2); Among them, n umax The speed of the reduction motor 1 corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor 1; g is the acceleration due to gravity; T min The minimum ramp time that can be set for frequency converter 25.

[0041] In one embodiment, the acceleration ramp parameter T of the inverter 25 is da Determined by formula 3 as the initial setting value: (Formula 3); Among them, n dmax The speed of the reduction motor 1 corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor 1; g is the acceleration due to gravity; T min The minimum ramp time that can be set for frequency converter 25.

[0042] In one embodiment, the deceleration ramp parameter T of the inverter 25 is dd Determined by formula 4 as the initial setting value: (Formula 4); Where m is the total mass of the grabbing mechanism and the drop weight; n dmax The speed of the reduction motor 1 corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor 1; η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time that can be set for frequency converter 25.

[0043] The second object of the present disclosure is to provide an automatic cycle control method used by the variable frequency drop weight impact testing machine, comprising the following steps: S1: Initialization, setting the value of the automatic cycle number N, and clearing the counters C0 and C1 inside the programmable controller 24 to 0; S2: When there is no signal at the input pin X4 of the programmable controller 24, it is in the automatic cycle control mode, and only the output pin Y5 outputs a signal, and the first cylinder 18 and the second cylinder 19 are lifted; S3: When there is a signal at the input pin X5 of the programmable controller 24, only the output pins Y0, Y2, Y3, and Y5 output signals, and the grabbing mechanism 11 is lifted at the first constant speed setting value, and the delay starts at the same time; S4: After a 0.5 - second delay, when there is no signal at the input pin X3 of the programmable logic controller 24, it indicates that the grasping mechanism 11 has successfully grasped, and only the output pins Y0, Y2, Y3, Y5 output signals. At the same time, C1 is cleared to 0, and the program transfers to S6; when there is a signal at the input pin X3 of the programmable logic controller 24, it indicates that the grasping mechanism 11 has failed to grasp, C1 counts once, and the program transfers to S5; S5: If C1 > 3, continue to S6; otherwise, if C1 < 3, then transfer to S2; otherwise, if C1 = 3, then transfer to S8; S6: When there is a signal at the input pin X1 of the programmable logic controller 24, only the output pins Y0, Y2, Y3, Y4 output signals, and the grasping mechanism 11 decelerates and rises until it stops; S7: When there is a signal at the input pin X0 of the programmable logic controller 24, C0 counts once, and at the same time, the delay starts; S8: When the delay seconds later, only the output pins Y1, Y2, Y4, Y5 output signals, and the grasping mechanism 11 lowers at the second constant - speed setting value; S9: When there is a signal at the input pin X2 of the programmable logic controller 24, only the output pins Y1, Y2, Y3, Y4, Y5 output signals, the grasping mechanism 11 decelerates and lowers until it stops, and at the same time, the first cylinder 18 and the second cylinder 19 lift up; S10: If C0 < N, return to S3; if C0 = N, end the operation.

[0044] In a certain embodiment, the first constant - speed setting value is n umax , and the second constant - speed setting value is n dmax ; When there are signals at both the first - constant - speed and second - constant - speed pins simultaneously, the first constant - speed setting value is n umax and the second constant - speed setting value is n dmax are both set to 0; g is the acceleration due to gravity, and N is the number of automatically - cycled times set by the user.

[0045] In a certain embodiment, N is determined according to actual needs, and is preferably 5 - 20 times.

[0046] Working principle: This disclosure mainly focuses on improving the electrical part, as well as the parameter setting and control method of the electrical part. The mechanical part can be implemented with reference to the existing technology. For example Figure 1As shown, the mechanical part of the testing machine includes a reduction motor 1, a guide wheel 2, a wire rope 3, a base 4, a channel steel column 5, a drop weight 6, two cylindrical guide rails 9, a grabbing mechanism 11, a top plate 13, a chain 14, a sprocket set 15, a wedge mechanism 16, a cylinder mounting plate 17, a first cylinder 18, and a second cylinder 19; the first cylinder 18 and the second cylinder 17 are symmetrically installed above the base 4, and the cylinder body is fixedly connected to the channel steel column 5 through the cylinder mounting plate 18; the reduction motor The machine 1 is installed inside the base 4, and the output shaft of the reduction motor 1 is connected to the guide wheel 2 through a key; the guide wheel 2 is fixed with a wire rope 3 and wound in the rope groove; the other end of the wire rope 3 is connected to the chain 14, along the inner side of the channel steel column 5, and then connected to the grabbing mechanism 11 after passing through the sprocket 15 installed above the top plate 13; the top of the drop hammer 6 has a protruding ball head 601, which can be inserted into the grabbing mechanism 11 and reliably connected to it; the drop hammer 6 and the grabbing mechanism 11 can slide up and down along the cylindrical guide rails 9 on both sides. Assume that the deceleration and lifting ramp parameter set in the inverter is T ud The deceleration ramp parameter is T dd The maximum vertical movement stroke of the gripping mechanism is H, the equivalent diameter of the guide wheel 2 after the wire rope 3 is wound is d, and the reduction ratio of the reduction motor 1 is i. The first proximity switch 12 to the fourth proximity switch 7 are installed in sequence from the top to the bottom of the testing machine. The installation position of the first proximity switch 12 is the position where the wedge-shaped mechanism 16 is fully inserted into the gripping mechanism 11 and is horizontally aligned with the upper plane of the gripping mechanism 11, and this is used as the relative size zero reference for the installation of the second proximity switch 10 to the third proximity switch 8; the installation position of the second proximity switch 10 is at a distance from the first proximity switch 12. The distance between the third proximity switch 8 and the first proximity switch 12 is ; The fourth proximity switch 7 is located between the third proximity switch 8 and the upper plane of the drop hammer 6 when it is in the initial position; a countersunk hole is opened on the side opposite to the drop hammer 6 and the fourth proximity switch 7, and a cylindrical permanent magnet is installed inside, and the length of the permanent magnet is consistent with the depth of the countersunk hole; when the grasping mechanism 11 is connected to the drop hammer 6 and moves up and down, the first proximity switch 12 to the third proximity switch 8 can all sense the grasping mechanism, and the fourth proximity switch 7 can sense the permanent magnet on the drop hammer 6.

[0047] In order to minimize the operating cycle of the test machine, in addition to the above-mentioned requirements for the installation position of the proximity switch, the inverter acceleration and deceleration ramp parameters also need to be optimized. Specifically, the acceleration ramp parameter T ua , deceleration ramp parameter T ud , Acceleration ramp parameter T da , deceleration ramp parameter T dd Determined by the following formulas as initial setting values: (Formula 1); (Formula 2); (Formula 3); (Formula 4); In the above formulas, m is the total mass of the grabbing mechanism 11 and the drop weight 6; n umax is the speed of the reduction motor 1 corresponding to the maximum linear speed during lifting, which shall not exceed the rated speed of the reduction motor 1; η is the total mechanical efficiency of the testing machine; g is the acceleration of gravity; T min The minimum ramp time allowed for the inverter.

[0048] like Figure 2 As shown, the programmable controller peripheral interface diagram of the electrical part of the test machine, combined with Figure 1 , consisting of the first proximity switch 12 to the fourth proximity switch 7, the automatic / manual selection switch 20, the lifting button 21, the lowering button 22, the stop button 23, the programmable controller 24, the frequency converter 25, and the pneumatic electromagnetic reversing valve 26; the first proximity switch 12 to the fourth proximity switch 7, the automatic / manual selection switch 20, the lifting button 21, the lowering button 22 and the stop button 23 are respectively connected to the input pins X0-X7 of the programmable controller 24; the output pins Y0-Y5 of the programmable controller 24 are respectively connected to the forward, reverse, start, first constant speed, second constant speed pins of the frequency converter 25 and the pneumatic electromagnetic reversing valve 26. The automatic cycle control method of the testing machine corresponding to the interface diagram includes the following steps: (1) Initialization, setting the value of the automatic cycle number N, and clearing the counters C0 and C1 inside the programmable controller 24 to 0; (2) When there is no signal at the input pin X4 of the programmable controller 24, it is in the automatic cycle control mode, and only the output pin Y5 outputs a signal, and the cylinder is lifted; (3) When there is a signal at the input pin X5 of the programmable controller 24, only the output pins Y0, Y2, Y3, and Y5 output signals, and the grabbing mechanism is lifted at the first constant speed setting value, and the delay starts at the same time; (4) After a delay of 0.5 seconds, when there is no signal at the input pin X3 of the programmable controller 24, it indicates that the capture is successful, and only the output pins Y0, Y2, Y3, and Y5 output signals. At the same time, C1 is cleared to 0, and the process goes to step 6. When there is a signal at the input pin X3 of the programmable controller 24, it indicates that the capture is unsuccessful, C1 counts once, and the process goes to the next step. (5) When C1 is less than 3, go to step 2; when C1 is equal to 3, go to step 8; (6) When there is a signal at the input pin X1 of the programmable controller 24, only the output pins Y0, Y2, Y3, and Y4 output signals, and the grabbing mechanism decelerates and lifts to a stop; (7) When there is a signal at the input pin X0 of the programmable controller 24, C0 counts once and the delay starts at the same time; (8) When the delay After seconds, only the output pins Y1, Y2, Y4, and Y5 output signals, and the grabbing mechanism is lowered at the second constant speed setting value; (9) When there is a signal at the input pin X2 of the programmable controller 24, only the output pins Y1, Y2, Y3, Y4, and Y5 output signals, the grabbing mechanism decelerates and lowers to a stop, and the cylinder is lifted at the same time; (10) When C0 is less than N, go to step 3; when C0 is equal to N, end; Where g is the acceleration due to gravity, and N is the number of automatic cycles set manually. The first constant speed setting value is n umax , the second fixed speed setting value is n dmax When the first and second fixed speed pins have signals at the same time, the speed setting value is 0.

[0049] In summary, through the unique design of the present invention, compared with the prior art, the present invention has the following beneficial effects: (a) The two-degree-of-freedom positioning turntable high-precision servo control system provided by the present invention installs the sensors on the final controlled object rather than on the servo motor, which ensures the directness of data acquisition in structure and provides a prerequisite for high-precision control. (b) The various control parameters of the automatic cycle control method provided by the present invention, first of all, have calculation formulas to follow, which is convenient for users; secondly, the control parameters are designed according to the damping ratio of the system open-loop transfer function as critical damping, avoiding the occurrence of overshoot; finally, the parameter adjustment also fully considers the limit output capacity of the servo amplifier within the linear range, so that the response capability of the system is maximized and the response speed is greatly improved. (c) The various operations adopted by the present invention are very common operations, which are very suitable for program design of controllers such as programmable controllers, which is convenient for users.

[0050] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A variable frequency drop weight impact testing machine, comprising a mechanical part and an electrical part that cooperate with each other, wherein the mechanical part comprises a reduction motor (1), a guide wheel (2), a steel wire rope (3), a base (4), a channel steel column (5), a drop weight (6), two cylindrical guide rails (9), a grabbing mechanism (11), a top plate (13), a chain (14), a sprocket group (15), a wedge mechanism (16), a cylinder mounting plate (17), a first cylinder (18), and a second cylinder (19); The first cylinder (18) and the second cylinder (19) are symmetrically arranged on the left and right sides of the base (4), and the cylinder bodies of the first cylinder (18) and the second cylinder (19) are respectively fixedly connected to the channel steel column (5) through the cylinder mounting plate (17); The reduction motor (1) is arranged inside the base (4), the output shaft of the reduction motor (1) is key-connected to the guide wheel (2), one end of the steel wire rope (3) is fixed and wound around the guide wheel (2), and the other end of the steel wire rope (3) passes through the inside of the channel steel column (5) from bottom to top and is connected to one end of the chain (14); The top plate (13) is arranged on the top of the mechanical part, the sprocket group (15) is arranged on the top of the top plate (13), and the other end of the chain (14) is wound around the sprocket group (15) and then hung downward on the top of the grabbing mechanism (11); The drop hammer (6) is located directly below the grabbing mechanism (11), and a ball head (601) is provided on the top of the drop hammer (6) that can be inserted into the grabbing mechanism (11) and reliably connected thereto; the two cylindrical guide rails (9) are located between the base (4) and the top plate (13) in the longitudinal direction, and the two cylindrical guide rails (9) are located on the left and right sides of the base (4) in the transverse direction, respectively; the drop hammer (6) and the grabbing mechanism (11) can be slidably connected to the two cylindrical guide rails (9) respectively; It is characterized in that The electrical part comprises a first proximity switch (12), a second proximity switch (10), a third proximity switch (8), a fourth proximity switch (7), an automatic / manual selection switch (20), a lifting button (21), a lowering button (22), a stop button (23), a programmable controller (24), a frequency converter (25), and a pneumatic electromagnetic reversing valve (26); The first proximity switch (12), the second proximity switch (10), the third proximity switch (8), the fourth proximity switch (7), the automatic / manual selection switch (20), the lifting button (21), the lowering button (22), and the stop button (23) are respectively connected to the X0-X7 input pins of the programmable controller (24); The Y0-Y5 output pins of the programmable controller (24) are respectively connected to the forward rotation, reverse rotation, start, first constant speed, second constant speed pins of the frequency converter (25) and the pneumatic electromagnetic reversing valve (26); The first proximity switch (12), the second proximity switch (10), the third proximity switch (8), and the fourth proximity switch (7) are arranged on the testing machine in sequence from top to bottom.

2. The variable frequency drop weight impact testing machine according to claim 1, characterized in that: The first cylinder (18) and the second cylinder (19) are preferably high-speed cylinders with the same specifications; The fourth proximity switch (7) is preferably an omnipolar Hall proximity switch.

3. The variable frequency drop weight impact testing machine according to claim 2, characterized in that: The frequency converter (25) is provided with a deceleration ramp parameter T ud , deceleration ramp parameter T dd ; n dmax is the speed of the reduction motor (1) corresponding to the maximum linear speed during lowering; n umax The speed of the reduction motor (1) corresponding to the maximum linear speed during lifting; The maximum vertical movement stroke of the grabbing mechanism (11) is H; The equivalent diameter of the guide wheel (2) after being wound around the steel wire rope (3) is d; The reduction ratio of the reduction motor (1) is i.

4. The variable frequency drop weight impact testing machine according to claim 3, characterized in that: When the gripping mechanism (11) slides until the wedge-shaped mechanism (16) is fully inserted therein, the first proximity switch (12) is flush with the upper plane of the gripping mechanism (11); The distance between the second proximity switch (10) and the first proximity switch (12) is 25T ud πd / i; The distance between the third proximity switch (8) and the first proximity switch (12) is H-25T dd πd / i; The fourth proximity switch (7) is located between the upper plane of the drop hammer (6) at the initial position and the third proximity switch (8); an opening is provided on the side of the drop hammer (6) facing the fourth proximity switch (7), and a permanent magnet is provided in the opening, and the length of the permanent magnet is consistent with the depth of the opening; when the grasping mechanism (11) is connected and drives the drop hammer (6) to move up and down, the first proximity switch (12), the second proximity switch (10), and the third proximity switch (8) can all sense the grasping mechanism (11), and the fourth proximity switch (7) can thereby sense the permanent magnet.

5. The variable frequency drop weight impact testing machine according to claim 3, characterized in that: The acceleration ramp parameter T of the frequency converter (25) ua Determined by formula 1 as the initial setting value: Wherein, m is the total mass of the grabbing mechanism (11) and the drop weight (6); n umax The speed of the reduction motor (1) corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor (1); η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time allowed to be set for the frequency converter (25).

6. The variable frequency drop weight impact testing machine according to claim 3, characterized in that: The deceleration ramp parameter T of the frequency converter (25) ud Determined by formula 2 as the initial setting value: Among them, n umax The speed of the reduction motor (1) corresponding to the maximum linear speed during lifting shall not exceed the rated speed of the reduction motor (1); g is the acceleration due to gravity; T min The minimum ramp time allowed to be set for the frequency converter (25).

7. The variable frequency drop weight impact testing machine according to claim 3, characterized in that: The acceleration ramp parameter T of the frequency converter (25) da Determined by formula 3 as the initial setting value: Among them, n dmax The speed of the reduction motor (1) corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor (1); g is the acceleration due to gravity; T min The minimum ramp time allowed to be set for the frequency converter (25).

8. The variable frequency drop weight impact testing machine according to claim 3, characterized in that: The deceleration ramp parameter T of the frequency converter (25) dd Determined by formula 4 as the initial setting value: Where m is the total mass of the grabbing mechanism and the drop weight; n dmax The speed of the reduction motor (1) corresponding to the maximum linear speed during lowering shall not exceed the rated speed of the reduction motor (1); η is the total mechanical efficiency of the testing machine; g is the acceleration due to gravity; T min The minimum ramp time allowed to be set for the frequency converter (25).

9. The automatic cycle control method of the variable frequency drop weight impact testing machine according to claims 3 to 8, characterized in that: The following steps are involved: S1: Initialization, setting the value of the automatic cycle number N, and clearing the counters C0 and C1 inside the programmable controller (24); S2: When there is no signal at the input pin X4 of the programmable controller (24), it is in automatic cycle control mode, and only the output pin Y5 outputs a signal, and the first cylinder (18) and the second cylinder (19) are lifted; S3: When there is a signal at the input pin X5 of the programmable controller (24), only the output pins Y0, Y2, Y3 and Y5 output signals, and the grabbing mechanism (11) is lifted at the first constant speed setting value, and the delay starts at the same time; S4: After a delay of 0.5 seconds, when there is no signal at the input pin X3 of the programmable controller (24), it indicates that the grasping mechanism (11) has grasped successfully, and only the output pins Y0, Y2, Y3, and Y5 output signals, while C1 is cleared to 0, and the process proceeds to S6; when there is a signal at the input pin X3 of the programmable controller (24), it indicates that the grasping mechanism (11) has failed to grasp, C1 counts once, and the process proceeds to S5; S5: If C1>3, continue to S6; otherwise, if C1<3, go to S2; otherwise, if C1=3, go to S8; S6: When there is a signal at the input pin X1 of the programmable controller (24), only the output pins Y0, Y2, Y3, and Y4 output signals, and the grabbing mechanism (11) decelerates and lifts to a stop; S7: When there is a signal on the input pin X0 of the programmable logic controller (24), C0 counts once, and at the same time, the delay starts; S8: When the delay After 10 seconds, only the output pins Y1, Y2, Y4 and Y5 output signals, and the grabbing mechanism (11) is lowered at a second constant speed setting value; S9: When there is a signal on the input pin X2 of the programmable logic controller (24), only the output pins Y1, Y2, Y3, Y4, and Y5 output signals. The grasping mechanism (11) decelerates and lowers until it stops. At the same time, the first cylinder (18) and the second cylinder (19) lift up; S10: If C0 < N, return to S3; if C0 = N, end the operation.

10. The automatic circulation control method according to claim 9, characterized in that: The first constant speed setting value is n umax The second fixed speed setting value is n dmax ; When the first fixed speed pin and the second fixed speed pin have signals at the same time, the first fixed speed setting value is n umax , the second constant speed setting value is n dmax All are set to 0; g is the acceleration due to gravity, and N is the number of automatic cycles set by the user.

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