A constant magnetic force preloading mechanism and a control method thereof

Abstract

The application discloses a constant magnetic force preloading mechanism and a control method thereof, which comprises a mounting base, a high-precision motion platform and a slider combination arranged on the mounting base, a magnetic force device arranged on the slider combination, a steel wire rope connecting the high-precision motion platform and the magnetic force device, a roller combination arranged on the top of the mounting base and a tension sensor for measuring the tension of the high-precision motion platform, the steel wire rope is arranged on the roller combination, and the high-precision motion platform and the magnetic force device are arranged on the two sides of the mounting base; when the high-precision motion platform accelerates or decelerates, the magnetic force of the magnetic force device changes according to the tension change of the high-precision motion platform; the magnetic force device can greatly ensure that the magnetic force is consistent with the tension of the high-density motion platform, and effectively improves the positioning precision of the high-precision motion platform.

Description

Technical Field

[0001] The invention belongs to the field of motion platforms and relates to a constant magnetic preload mechanism and a control method thereof. Background Art

[0002] With the development of modern science and technology, the demand for large-scale motion platforms with high precision and resolution is becoming more and more urgent. Such platforms are widely used in fields such as IC manufacturing equipment, ultra-precision machining and measurement, biomedical engineering, aerospace, etc.

[0003] When a high-precision motion platform is carrying a load and performing acceleration and deceleration in the vertical direction, the force will change, but the counterweight cannot be changed in real time, resulting in an imbalance between the counterweight and the load, and the positioning accuracy of the high-precision motion platform is not high. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a constant magnetic preload mechanism and a control method thereof.

[0005] To achieve the above-mentioned purpose, the following technical solutions can be adopted: a constant magnetic preload mechanism, comprising a mounting base, a high-precision motion platform and a slider combination arranged on the mounting base, a magnetic device arranged on the slider combination, a steel wire rope connecting the high-precision motion platform and the magnetic device, a roller combination arranged on the top of the mounting base, and a tension sensor for measuring the tension of the high-precision motion platform, wherein the steel wire rope is arranged on the roller combination, and the high-precision motion platform and the magnetic device are arranged on both sides of the mounting base; when the high-precision motion platform accelerates and decelerates, the magnetic force of the magnetic device changes according to the change in the tension of the high-precision motion platform.

[0006] More specifically, the magnetic device includes a magnetic block and an electromagnet provided on the slider assembly, and a distance L is left between the magnetic block and the electromagnet.

[0007] More specifically, the distance L between the magnetic block and the electromagnet is constant.

[0008] More specifically, the slider assembly includes a slide rail fixedly arranged on the mounting base, a slider slidably arranged on the slide rail, an adjustment plate arranged on the slider, and a flat motor providing power to the slider, the magnetic block is arranged on the adjustment plate, and the slide rail is arranged vertically.

[0009] More specifically, a first grating scale is provided between the slider and the mounting base.

[0010] More specifically, a second grating ruler is provided on the high-precision motion platform.

[0011] More specifically, the roller assembly includes a fixing seat fixedly arranged on the top of the mounting base, a roller frame fixedly arranged on the fixing seat, and a roller arranged on the roller frame, and the steel wire rope is arranged on the roller.

[0012] More specifically, the roller assembly is provided in two groups, and the two rollers are provided away from each other and protrude from the mounting base.

[0013] A control method for a constant magnetic preload mechanism, the operating steps are as follows:

[0014] S1. Setting a load on the high-precision motion platform, and setting the distance between the magnetic block and the electromagnet and the initial magnetic force of the electromagnet according to the load;

[0015] S2. When the high-precision motion platform accelerates and decelerates, the electromagnet moves synchronously, the flat motor drives the slider to move, and the slider and the electromagnet are relatively stationary;

[0016] S3, the tension sensor detects a change in tension and transmits a signal to the processor;

[0017] S4. The processor calculates the required current value and adjusts the current of the electromagnet. When the current changes, the magnetic force also changes accordingly. The magnetic force of the electromagnet always remains consistent with the pulling force of the high-precision motion platform.

[0018] More specifically, the calculation formula for the current value required in S4 is as follows:

[0019]

[0020] Where: F—electromagnetic attraction (N)

[0021] S—core cross-sectional area (m 2 )

[0022] I—Coil current (A)

[0023] N—Number of coil turns (turns)

[0024] R m —Magnetic resistance (H -1 ).

[0025] The present invention provides a constant magnetic preload mechanism and a control method thereof, which can achieve the following technical effects: the tension of the high-precision motion platform changes during acceleration and deceleration, and transmits a signal to the processor in real time. The processor calculates the signal transmitted by the tension sensor and then synchronously adjusts the magnetic force of the magnetic device. The magnetic device can ensure that the magnetic force is consistent with the tension of the high-density motion platform to the greatest extent, effectively improving the positioning accuracy of the high-precision motion platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention Figure 1 ;

[0027] Figure 2 The present invention Figure 1 Enlarged view of point A in the middle;

[0028] Figure 3 This is a schematic diagram of the three-dimensional structure of the present invention Figure 2 ;

[0029] Figure 4 It is a right side structural schematic diagram of the present invention;

[0030] Figure 5 The present invention Figure 4 Enlarged view of point B in the middle;

[0031] In the figure: 1. Mounting base; 2. High-precision motion platform; 31. Slide rail; 32. Slider; 33. Flat motor; 34. First grating scale; 35. Adjustment plate; 41. Magnetic block; 42. Electromagnet; 5. Wire rope; 61. Fixed seat; 62. Roller frame; 63. Roller; 7. Tension sensor. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. In the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are only some of the embodiments of the present invention, but not all of them. The embodiments described below with reference to the accompanying drawings are only some of the embodiments of the present invention, but not all of them.

[0033] The embodiments described below with reference to the accompanying drawings are illustrative and intended to explain the present invention. They are not to be construed as limiting the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the scope of protection of the present invention. The embodiments of the present invention are described in detail below.

[0035] A constant magnetic preload mechanism, such as Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 as well as Figure 5 As shown, the invention comprises a mounting base 1, a high-precision motion platform 2 and a slider assembly mounted on the mounting base 1, a magnetic device mounted on the slider assembly, a wire rope 5 connecting the high-precision motion platform 2 and the magnetic device, a roller assembly mounted on the top of the mounting base 1, and a tension sensor 7 for detecting the tension of the high-precision motion platform 2. The high-precision motion platform 2 and the magnetic device are mounted on both sides of the mounting base 1. When the high-precision motion platform 2 moves up and down, the magnetic device also moves up and down synchronously, and the movement distance of the magnetic device and the high-precision motion platform 2 is consistent. The tension sensor 7 adjusts the current of the magnetic device according to the change in tension during the up and down movement of the high-precision motion platform 2, thereby adjusting the magnitude of the magnetic force, so that the magnetic force and the tension are always consistent. The tension sensor 7 can detect the change in tension during the movement of the high-precision motion platform 2 and transmit a signal to the processor in real time. The processor adjusts the magnetic force of the magnetic device according to the signal transmitted by the tension sensor 7. The magnetic device can greatly ensure that the magnetic force is consistent with the tension of the high-precision motion platform 2, effectively improving the positioning accuracy of the high-precision motion platform 2.

[0036] like Figure 1 、 Figure 3 、 Figure 4 As shown, the slider assembly includes a slide rail 31 fixed on the mounting base 1, a slider 32 slidably arranged on the slide rail 31, an adjustment plate 35 arranged on the slider 32, and a flat motor 33. The slide rail 31 is vertically arranged on the mounting base 1, which can facilitate the vertical movement of the magnetic device. The slide rail 31 has a guiding function; the magnetic device is arranged on the adjustment plate 35, and the position of the adjustment plate 35 is adjusted before installing the magnetic device. After the position of the magnetic device is determined, the adjustment plate 35 is fixed to the slider 32; a flat motor 33 and a first grating scale 34 are arranged between the mounting base 1 and the slider 32. The flat motor 33 gives power to the slider 32, so that the slider 32 moves up and down. The first grating scale 34 can provide position feedback of the slider 32 to ensure that the movement distance of the slider 32 is consistent with the movement distance of the high-precision motion platform 2.

[0037] like Figure 1 、 Figure 3 、 Figure 4 as well as Figure 5As shown, the magnetic device includes a magnetic block 41 arranged on the adjustment plate 35 and an electromagnet 42 adsorbed in the air with the magnetic block 41, and a certain distance L is maintained between the magnetic block 41 and the electromagnet 42. When the electromagnet 42 moves up and down, the magnetic block 41 follows the electromagnet 42 to move synchronously, and the distance L between the magnetic block 41 and the electromagnet 42 remains unchanged; the distance L between the magnetic block 41 and the electromagnet 42 is adjusted according to the load set on the high-precision motion platform before the mechanism is operated. The distance L between the magnetic block 41 and the electromagnet 42 is different for different loads; the electromagnet 42 can change the magnetic force of the electromagnet 42 by changing the current. A hook is fixed on the top of the electromagnet 42, and the wire rope 5 is set on the hook. When the electromagnet 42 moves up and down, the wire rope 5 will not fall off the hook, and the other end of the wire rope 5 is fixed to the high-precision motion platform 2.

[0038] A second grating ruler is provided on the high-precision motion platform 2 , and the second grating ruler can provide position feedback of the high-precision motion platform 2 to ensure that the movement distance of the slider 32 is consistent with the movement distance of the high-precision motion platform 2 .

[0039] like Figure 1 、 Figure 3 、 Figure 4 As shown, a tension sensor 7 is provided between the high-precision motion platform 2 and the electromagnet 42. The tension sensor 7 is used to detect the tension of the high-precision motion platform 2 during the movement and transmit it to the processor in real time. The processor adjusts the current of the electromagnet 42 in real time and changes the magnetic force of the electromagnet 42 to ensure that the real-time tension is consistent with that of the high-precision motion platform 2; a hook is provided on the top of the tension sensor 7, and the wire rope 5 is provided on the hook. When the high-precision motion platform 2 moves up and down, the wire rope 5 will not slip off the hook, and the other end of the wire rope 5 fixes the electromagnet 42.

[0040] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4As shown, a roller assembly is provided on the mounting base 1, and the roller assembly includes a fixed seat 61, a roller frame 62 fixedly provided on the fixed seat 61, and a roller 63 provided on the roller frame 62. The wire rope 5 is provided on the roller 63 to reduce the friction force when the high-precision motion platform 2 and the electromagnet 42 move; the roller assembly is provided in two groups, which are respectively provided on both sides of the mounting base 1 where the high-precision motion platform 2 and the electromagnet 42 are provided, and the two fixed seats 61 protrude from the two side surfaces where the high-precision motion platform 2 and the electromagnet 42 are provided, respectively. The roller frame 62 is provided on a side surface where the fixed seat 61 protrudes, and the roller 63 is provided at the highest point of the roller frame 62, so that the roller 63 protrudes from the fixed seat 61, ensuring that when the wire rope 5 is provided on the roller 63, the wire rope 5 does not contact the mounting base 1 and the fixed seat 61, thereby avoiding friction with the mounting base 1 and the fixed seat 61, resulting in the wire rope 5 being broken by friction with the mounting base 1 or the fixed seat 61 when being pulled by both sides.

[0041] The control method of the constant magnetic preload mechanism is specifically described as follows:

[0042] A load is set on the high-precision motion platform 2. After the load is set, the position of the adjustment plate 35 is adjusted. After the position of the adjustment plate 35 is adjusted, the magnetic block 41 is set on the adjustment plate 35. Then, the distance L between the magnetic block 41 and the electromagnet 42 is adjusted. At the same time, the magnetic force of the electromagnet 42 is adjusted to ensure that, at the beginning, the magnetic force of the electromagnet 42 is consistent with the load on the high-precision motion platform 2. When the high-precision motion platform 2 moves up and down, due to the traction of the wire rope 5, the electromagnet 42 moves up and down synchronously with the high-precision motion platform 2, and the movement distance between the high-precision motion platform 2 and the electromagnet 42 is always consistent. When the electromagnet 42 moves up and down, the flat plate electromagnet The machine 33 drives the slider 32 to move up and down following the electromagnet 42, and the slider 32 drives the magnetic block 41 to move up and down, and the distance L between the magnetic block 41 and the electromagnet 42 is always kept consistent; when the high-precision motion platform 2 accelerates or decelerates, the tension of the high-precision motion platform 2 changes, and the tension sensor 7 arranged at the high-precision motion platform 2 detects the change in the tension of the high-precision motion platform 2 and transmits the signal to the processor. The processor calculates and obtains the required current value, and changes the current of the electromagnet 42, thereby changing the magnetic force of the electromagnet 42, so that the magnetic force of the electromagnet 42 is consistent with the tension of the high-precision motion platform 2.

[0043] The electromagnet 42 converts electrical energy into magnetic field energy. Since electricity is divided into direct current and alternating current, their regulation rules are different. In this solution, only the effect of direct current on the magnetic force F is analyzed. The calculation formula of magnetic force F is as described in Formula 1:

[0044]

[0045] From formula 1, it can be seen that the magnetic force F is only related to the magnetic induction intensity B;

[0046] The formula for calculating the magnetic flux Φ is shown in formula 2 and formula 3, and formula 4 and formula 5 can be derived from formula 2 and formula 3;

[0047]

[0048] φ = BS ③

[0049]

[0050]

[0051] Reluctance R m is the resistance of the magnetic flux Φ when passing through the magnetic circuit, and the size of the magnetic reluctance R m is proportional to the length L of the magnetic circuit, so it can be seen from formula 5 that the magnetic induction intensity B is related to the current I and the air gap (i.e. the distance between the magnetic force block 41 and the electromagnet 42). In the case that the distance between the electromagnet 42 and the magnetic force block 41 is constant, the magnetic induction intensity B is only related to the current I. When the current I increases, the magnetic induction intensity B also increases, and when the current I decreases, the magnetic induction intensity B also decreases.

[0052] By substituting formula 5 into formula 1, formula 6 for calculating the required current value of the electromagnet 42 can be obtained:

[0053]

[0054] From formula 6, it can be seen that the magnetic force F of the electromagnet 42 is related to the current I. When the current I increases, the magnetic force F increases, and when the current I decreases, the magnetic force F decreases.

[0055] In the formula: F—magnetic force (N)

[0056] B—magnetic induction intensity (T)

[0057] S—cross-sectional area of the core (m 2 )

[0058] I—coil current (A)

[0059] N—number of turns of the coil (turns)

[0060] Φ—magnetic flux (W b )

[0061] R m —magnetic reluctance (H -1 )

[0062] The present invention provides a constant magnetic preload mechanism and method thereof, which can achieve the following technical effects: the tension sensor 7 is set to detect the tension of the high-precision motion platform 2 during acceleration and deceleration in real time; the electromagnet 42 is set to change the magnetic force in real time according to the tension change of the high-precision motion platform 2, thereby improving the repeatability of the positioning accuracy of the high-precision motion platform 2; the flat motor 33 is set to drive the magnetic block 41 to move up and down, ensuring that the distance between the magnetic block 41 and the electromagnet 42 remains unchanged; the roller 63 is set to prevent the steel wire rope 5 from breaking due to friction with the mounting base 1.

[0063] The preferred embodiments of the invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0064] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0065] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A constant magnetic preload mechanism, characterized in that: The invention comprises a mounting base (1), a high-precision motion platform (2) and a slider assembly arranged on the mounting base (1), a magnetic device arranged on the slider assembly, a steel wire rope (5) connecting the high-precision motion platform (2) and the magnetic device, a roller assembly arranged on the top of the mounting base (1), and a tension sensor (7) for measuring the tension of the high-precision motion platform (2), wherein the steel wire rope (5) is arranged on the roller assembly, and the high-precision motion platform (2) and the magnetic device are arranged on both sides of the mounting base (1); when the high-precision motion platform (2) accelerates and decelerates, the magnetic force of the magnetic device changes according to the change of the tension of the high-precision motion platform (2); The magnetic device comprises a magnetic block (41) and an electromagnet (42) arranged on the slider assembly, with a distance L being left between the magnetic block (41) and the electromagnet (42); The slider assembly comprises a slide rail (31) fixedly arranged on the mounting base (1), a slider (32) slidably arranged on the slide rail (31), an adjustment plate (35) arranged on the slider (32), and a flat motor (33) providing power to the slider (32); the magnetic block (41) is arranged on the adjustment plate (35); the slide rail (31) is arranged vertically; and the steel wire rope (5) is fixed to the electromagnet (42); When the high-precision motion platform (2) moves up and down, due to the traction of the wire rope (5), the electromagnet (42) moves up and down synchronously with the high-precision motion platform (2), and the movement distance between the high-precision motion platform (2) and the electromagnet (42) is always consistent. When the electromagnet (42) moves up and down, the flat motor (33) drives the slider (32) to move up and down following the electromagnet (42), and the slider (32) drives the magnetic block (41) to move up and down as well, and the distance L between the magnetic block (41) and the electromagnet (42) is always consistent.

2. The constant magnetic preload mechanism according to claim 1, characterized in that: A first grating ruler (34) is provided between the slider (32) and the mounting base (1).

3. The constant magnetic preload mechanism according to claim 2, characterized in that: A second grating ruler is provided on the high-precision motion platform (2).

4. The constant magnetic preload mechanism according to claim 1, characterized in that: The roller assembly comprises a fixing seat (61) fixedly arranged on the top of the mounting base (1), a roller frame (62) fixedly arranged on the fixing seat (61), and a roller (63) arranged on the roller frame (62), and the steel wire rope (5) is arranged on the roller (63).

5. The constant magnetic preload mechanism according to claim 4, characterized in that: The roller assembly is provided in two groups, and the two rollers (63) are provided away from each other and protrude from the mounting base (1).

6. A method for controlling a constant magnetic preload mechanism, characterized in that: The constant magnetic preload mechanism according to any one of claims 1 to 5 is used, and the operating steps are as follows: S1, setting a load on the high-precision motion platform (2), and setting the distance between the magnetic block (41) and the electromagnet (42) and the initial magnetic force of the electromagnet (42) according to the load; S2. When the high-precision motion platform (2) accelerates and decelerates, the electromagnet (42) moves synchronously, the flat motor drives the slider to move, and the slider and the electromagnet are relatively stationary; S3, the tension sensor (7) detects a change in tension and transmits a signal to the processor; S4. The processor calculates the current value required by the electromagnet and adjusts the current of the electromagnet (42). When the current changes, the magnetic force also changes. The magnetic force of the electromagnet (42) is always consistent with the pulling force of the high-precision motion platform (2).

7. The control method of the constant magnetic preload mechanism according to claim 6, characterized in that: The calculation formula for the current value required in S4 is as follows: Where: F—electromagnetic attraction (N) S—core cross-sectional area (m 2 ) I—Coil current (A) N—Number of coil turns (turns) R m —Magnetic resistance (H -1 ).

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