Automatic excitation device and control method using object gravity method

Abstract

The present application relates to a kind of automatic excitation device and control method using object gravity method, including, force hammer, force hammer longitudinal movement unit, force hammer transverse movement unit and force hammer vertical movement unit, the force hammer longitudinal movement unit is detachably connected with rail, with the longitudinal direction of rail is arranged in the same direction, the force hammer vertical movement unit is vertically arranged on force hammer longitudinal movement unit, force hammer transverse movement unit is vertically arranged on force hammer vertical movement unit, force hammer is movably arranged on force hammer transverse movement unit, sensor is arranged on the force hammer, the force hammer longitudinal movement unit, force hammer transverse movement unit and force hammer vertical movement unit respectively drive force hammer in the longitudinal direction of rail, the lateral direction of rail moves.The present application can carry out full-automatic test, reduce test time, reduce the workload of personnel, and can adjust excitation size, keep the position and force of each knock consistent, avoid the situation of false knock, continuous hit.

Description

Technical Field

[0001] This invention relates to the field of rail testing technology, specifically to an automatic excitation device and control method utilizing the gravity of an object. Background Technology

[0002] To ensure the safety of railway track structures, regular inspections are necessary. Accelerometers are used to detect the natural frequency of the rails. An excitation is applied to the rail using a hammer (with a built-in accelerometer), and the time-domain signals of the excitation and response are collected. Modal analysis is then performed to assess the structural safety of the rails. To ensure data accuracy, each measurement requires only one excitation (continuous application is not allowed) and consistent excitation must be maintained.

[0003] Two excitation methods are commonly used in measurements: hammer excitation and vibrator excitation. Theoretically, the data collected by hammer excitation and vibrator excitation are identical. The only difference is that hammer excitation often involves keeping the accelerometer position constant while moving the hammer excitation position, whereas vibrator excitation involves keeping the excitation point constant while changing the sensor position. For rail modal measurement, the measurement point is fixed and the sensor position cannot be changed. Furthermore, existing vibrators are difficult to install and have insufficient excitation force, hence the hammer excitation method is chosen. However, since hammer striking is done manually, repeated striking cannot guarantee consistency in striking position and force. Furthermore, prolonged manual hammer striking leads to operator fatigue, resulting in problems such as mis-striking, repeated striking, excessively long testing times, and poor consistency. Summary of the Invention

[0004] In view of the above-mentioned shortcomings and deficiencies, the present invention provides an automatic excitation device and control method that utilizes the gravity of an object. The excitation magnitude is adjustable, and the position and force of each tap are consistent, thus avoiding accidental tapping or repeated tapping.

[0005] To achieve the above objectives, the main technical solution adopted by the present invention includes: a hammer, a longitudinal movement unit of the hammer, a transverse movement unit of the hammer, and a vertical movement unit of the hammer. The longitudinal movement unit of the hammer is detachably connected to the rail and is arranged in the same direction as the longitudinal direction of the rail. The vertical movement unit of the hammer is vertically arranged on the longitudinal movement unit of the hammer. The transverse movement unit of the hammer is vertically arranged on the vertical movement unit of the hammer. The hammer is movably arranged on the transverse movement unit of the hammer. A sensor is provided on the hammer. The longitudinal movement unit, the transverse movement unit, and the vertical movement unit of the hammer respectively drive the hammer to move in the longitudinal and transverse directions of the rail.

[0006] The longitudinal motion unit of the hammer includes a first motor, a first lead screw, and a clamping device. The longitudinal motion unit of the hammer is connected to the rail through the clamping device. The output end of the first motor is connected to the first lead screw. A first motion platform is mounted on the first lead screw. By controlling the first motor, the first motion platform moves longitudinally along the rail on the first lead screw.

[0007] The vertical motion unit of the hammer includes a second motor, a second lead screw, and a second motion platform. The output end of the second motor is fixedly connected to the first motion platform of the longitudinal motion unit of the hammer through the second lead screw. The second motion platform is sleeved on the second lead screw. By controlling the second motor, the second motion platform moves vertically along the rail on the second lead screw.

[0008] The lateral movement unit of the hammer includes a third motor and a third lead screw. The third motor is located inside the second motion platform, and the output end of the third motor is connected to the third lead screw. The hammer is mounted on the third lead screw via a connecting rod. By controlling the third motor, the hammer moves laterally along the rail on the third lead screw. The servo motor is connected to the hammer and controls the angle of the hammer in the vertical direction.

[0009] A control method for an automatic excitation device utilizing the gravity of an object involves communicating a first to third motor and a servo motor with an industrial host via Ethernet. The industrial host adjusts the spatial position of the hammer by sending position control commands to the first to third motors; calculates and adjusts the initial deflection angle of the hammer by sending the hammer striking force to the servo motor; and controls the switching on and off of the servo motor by the calculated striking time after the striking begins.

[0010] The process of calculating and adjusting the initial deflection angle of the hammer by sending a hammer strike force to the servo motor is as follows:

[0011] 101) By controlling the first to third motors, the hammer is positioned at the impact test position;

[0012] 102) Converting gravitational potential energy into kinetic potential energy: Where m is the weight of the hammer, g is the acceleration due to gravity, and L is the vertical height of the hammer relative to the rail; the hammer's striking speed is obtained through the formula.

[0013] 103) Calculate the instantaneous impact force F of the strike. , where t is the instantaneous contact time;

[0014] 104) Calculate the pressure P, P Where S is the contact area between the hammer and the rail;

[0015] 105) Calculate the striking force , ,in, ;

[0016] The relationship between the striking force and the deflection angle of the hammer is as follows:

[0017] The formula yields the deflection angle of the hammer. ;

[0018] The method of controlling the servo motor's on / off state by calculating the impact time specifically involves:

[0019] 201) Calculate the period T of the simple pendulum based on the length of the striking pendulum.

[0020] 202) Then set the striking time t of the hammer. 击 It is the sum of half the pendulum's time and the instantaneous contact time t, that is, t 击 = + t.

[0021] The present invention has the following beneficial effects and advantages:

[0022] The present invention utilizes an automatic excitation device and control method based on the gravity of an object to perform fully automatic testing, reduce test time, reduce the workload of personnel, and adjust the excitation magnitude to maintain the consistency of the position and force of each tap, thus avoiding accidental tapping or repeated tapping. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0024] The components are: 1. First motor; 2. Clamping device; 3. First motion platform; 4. First lead screw; 5. Second lead screw; 6. Second motion platform; 7. Second motor; 8. Third lead screw; 9. Servo motor; 10. Force hammer. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings. Figure 1 As shown, the present invention is an automatic excitation device utilizing the gravity of an object, comprising: a hammer 10, a longitudinal movement unit of the hammer, a transverse movement unit of the hammer, and a vertical movement unit of the hammer. The longitudinal movement unit of the hammer is detachably connected to the rail and is arranged in the same direction as the longitudinal direction of the rail. The vertical movement unit of the hammer is vertically arranged on the longitudinal movement unit of the hammer, and the transverse movement unit of the hammer is vertically arranged on the vertical movement unit of the hammer. The hammer 10 is movably arranged on the transverse movement unit of the hammer, and a sensor is provided on the hammer 10. The longitudinal movement unit, the transverse movement unit, and the vertical movement unit of the hammer respectively drive the hammer to move in the longitudinal and transverse directions of the rail.

[0026] The longitudinal motion unit of the hammer includes a first motor 1, a first lead screw 4 and a clamping device 2. The longitudinal motion unit of the hammer is connected to the rail through the clamping device 2. The output end of the first motor 1 is connected to the first lead screw 4. A first motion platform 3 is sleeved on the first lead screw 4. By controlling the first motor 1, the first motion platform 3 is moved longitudinally along the rail on the first lead screw 4.

[0027] Specifically, the first motion platform 3 is set at the rightmost end of the first lead screw 4 as the initial position of the hammer 10 in the longitudinal direction of the rail. The first motor 1 is controlled to realize the forward and reverse rotation of the first lead screw 4. When the first motor 1 rotates forward, it drives the first motion platform 3 to move to the left. When the first motor 1 rotates in reverse, it drives the first motion platform 3 to move to the right. After reaching the designated position, the stop button is pressed, the first motor 1 stops rotating, and the first motion platform 3 no longer moves.

[0028] The vertical motion unit of the hammer includes a second motor 7, a second lead screw 5, and a second motion platform 6. The output end of the second motor 7 is fixedly connected to the first motion platform 3 of the longitudinal motion unit of the hammer through the second lead screw 5. The second motion platform 6 is sleeved on the second lead screw 5. By controlling the second motor 7, the second motion platform 6 can be moved vertically along the rail on the second lead screw 5.

[0029] Specifically, the second motor is a brake motor, meaning that after the second motor is de-energized, the motor shaft is locked. When the hammer head of the hammer 10 is in a vertical position and closest to the first motion platform 3, it is the initial vertical position of the rail. The second motor 7 enables the motor to rotate forward and backward. When the second motor 7 rotates forward, the hammer 10 moves upward. When the second motor 7 rotates backward, the hammer 10 moves downward. After reaching the designated position, pressing the stop button stops the second motor from rotating and the hammer no longer moves.

[0030] The lateral movement unit of the hammer includes a third motor and a third lead screw 8. The third motor is located inside the second motion platform 6, and the output end of the third motor is connected to the third lead screw 8. The hammer 10 is mounted on the third lead screw 8 via a connecting rod. By controlling the third motor, the hammer 10 moves laterally along the rail on the third lead screw 8. The servo motor 9 is connected to the hammer 10, and the servo motor 9 controls the angle of the hammer 10 in the vertical direction.

[0031] Specifically, when the hammer 10 is closest to the second motion platform, it is the initial transverse position of the rail. The third motor enables forward and reverse rotation. When the third motor rotates forward, it moves the hammer 10 forward. When the third motor rotates in reverse, it moves the hammer backward. After reaching the designated position, pressing the stop button stops the third motor, and the hammer stops moving. The servo motor 9 and the connecting rod enable the hammer 10 to rotate 180 degrees. When the hammer 10 is parallel to the ground, it is the initial position of the hammer 10. That is, the hammering force is the greatest when the angle of the servo motor is 0 degrees. The force of the hammer 10 hitting the rail can be adjusted by adjusting the rotation angle of the hammer 10.

[0032] The first to third motors and servo motors communicate with the industrial host via Ethernet. The industrial host adjusts the spatial position of the hammer by sending position control commands to the first to third motors; it calculates and adjusts the initial deflection angle of the hammer by sending the hammer striking force to the servo motor; after the striking begins, it controls the switching on and off of the servo motor by the calculated striking time.

[0033] The process of calculating and adjusting the initial deflection angle of the hammer by sending a hammer strike force to the servo motor is as follows:

[0034] By controlling the first to third motors, the hammer is positioned at the impact test location;

[0035] Converting gravitational potential energy into kinetic potential energy: Where m is the weight of the hammer, g is the acceleration due to gravity, and L is the vertical height of the hammer relative to the rail; the hammer's striking speed is obtained through the formula.

[0036] Calculate the instantaneous impact force F of the strike. , where t is the instantaneous contact time;

[0037] Calculate the pressure P, P Where S is the contact area between the hammer and the rail;

[0038] Calculate the striking force , ,in, ;

[0039] The relationship between the striking force and the deflection angle of the hammer is as follows:

[0040]

[0041] The deflection angle of the hammer is obtained from the formula. ;

[0042] A control method for an automatic excitation device utilizing the gravity of an object, wherein the switching of a servo motor is controlled by calculating the impact time, specifically:

[0043] The period T of the simple pendulum is calculated based on the length of the striking pendulum.

[0044] Then set the impact time t of the hammer. 击 It is the sum of half the pendulum's time and the instantaneous contact time t, that is, t 击 = +t.

[0045] Specifically, in this embodiment, taking a 60kg / m steel rail as an example, the excitation device of the present invention is placed on the test span of the steel rail (the longitudinal direction of the steel rail and the longitudinal movement unit are in the same direction), and fixed by the clamping device 2. The position control command sent by the industrial host places the striking device at the center of the one-quarter mark of the steel rail. After receiving the control command via Ethernet, the first motor controls the forward and reverse rotation of the first motor to realize the movement of the first motion platform in the longitudinal direction of the steel rail. When the designated position is reached, a stop command is issued. Similarly, the excitation device can be moved in the lateral and vertical directions of the steel rail. When the excitation device reaches the designated position, a locking command is issued and the first to third motors stop rotating. After the hammer 10 reaches the designated position, the striking force is set to 3000N, that is... The value is 5000N; substituting into the formula:

[0046]

[0047] Given 5000 N, m = 0.5 kg, L = 0.1 m, and gravitational acceleration g = 10 m / s², we can assume the force is 5000 N, m = 0.5 kg, L = 0.1 m, and the gravitational acceleration g = 10 m / s². 2 t is 1 s, s is 0.001 m 2 S is in units of 1m 2 Substituting this into the equation, we obtain θ as 30°, which means setting the initial angle of the servo motor at 30°.

[0048] ;

[0049] Let L be 0.1m and gravitational acceleration g be 10m / s². 2 , Taking 3.14, we know that T = 6.28s.

[0050] t 击 = + t,

[0051] The time it takes for the hammer to reach the rail is half of the cycle, which is 3.14 seconds. Adding the contact time of 1 second, the total is 4.14 seconds. That is, 4.14 seconds.

Claims

1. An automatic excitation device using a method of object gravity, characterized by, It includes: The force hammer, the force hammer longitudinal movement unit, the force hammer transverse movement unit and the force hammer vertical movement unit, the force hammer longitudinal movement unit is detachable with the rail, and is arranged in the same direction with the longitudinal direction of the rail, the force hammer vertical movement unit is vertically arranged on the force hammer longitudinal movement unit, the force hammer transverse movement unit is vertically arranged on the force hammer vertical movement unit, the force hammer is movably arranged on the force hammer transverse movement unit, and a sensor is arranged on the force hammer, the force hammer longitudinal movement unit, the force hammer transverse movement unit and the force hammer vertical movement unit drive the force hammer to move in the longitudinal direction of the rail and the transverse direction of the rail respectively; The force hammer longitudinal movement unit includes a first motor, a first screw and a clamping device, the force hammer longitudinal movement unit is connected with the rail through the clamping device, the output end of the first motor is connected with the first screw, the first movement platform is sleeved on the first screw, and the first movement platform moves along the longitudinal direction of the rail on the first screw by controlling the first motor; The force hammer vertical movement unit includes a second motor, a second screw and a second movement platform, the output end of the second motor is fixedly connected with the first movement platform of the force hammer longitudinal movement unit through the second screw, and the second movement platform is sleeved on the second screw; the second movement platform moves along the vertical direction of the rail on the second screw by controlling the second motor; The force hammer transverse movement unit includes a third motor and a third screw, the third motor is arranged in the second movement platform, the output end of the third motor is connected with the third screw, the force hammer is arranged on the third screw through a connecting rod, and the force hammer moves along the transverse direction of the rail on the third screw by controlling the third motor; the rudder is connected with the force hammer, and the rudder controls the angle of the force hammer in the vertical direction.

2. The control method of an automatic excitation device using the object gravity method according to claim 1, characterized in that: The first motor, the second motor, the third motor and the rudder are communicated with the industrial host through Ethernet, the industrial host adjusts the spatial position of the force hammer by sending position control commands to the first motor, the second motor and the third motor; the initial deflection angle of the force hammer is calculated by sending the hitting force of the force hammer to the rudder; After the hitting starts, the switch of the rudder is controlled by the calculated hitting time.

3. The control method of an automatic activation device using the object gravity method according to claim 2, characterized in that, The initial deflection angle of the force hammer is calculated by sending the hitting force of the force hammer to the rudder, and the specific process is as follows: 101) the first motor, the second motor and the third motor are controlled to arrange the force hammer at the hitting test position; 102) converting the gravitational potential energy into kinetic potential energy: Wherein, m is the weight of the force hammer, g is the acceleration of gravity, L is the vertical height of the force hammer hitting compared to the rail; the force hammer hitting speed is obtained by the formula; 103) calculating the instantaneous impact force F of the hit, where t is the instantaneous contact time; 104) Calculate the pressure P, P = F / S where S is the contact area of the hammer with the rail; 105) calculating the hitting force , , wherein is the hitting area; 106) the relationship between the hitting force and the deflection angle of the force hammer is: Formula to get the force hammer deflection angle .

4. The control method of an automatic exciting device using the object gravity method according to claim 2, characterized in that, The switch of the rudder is controlled by the calculated hitting time, and the specific process is as follows: 201) The period of the simple pendulum T is calculated from the length of the stroke, ; 202) the striking time t of the force hammer is set 击 is the sum of half the pendulum time and the instant contact time t, i.e. 击 = +t.

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