SPM workbench supporting frame capable of automatically adjusting levelnessTechnical Field
The invention belongs to the technical field of leveling of a workbench of an experimental instrument, and particularly relates to an SPM workbench supporting frame capable of automatically adjusting levelness.
Background
The scanning probe microscope (Scanning Probe Microscope, SPM) includes a scanning tunneling microscope (Scanning Tunneling Microscope, STM) and an atomic force microscope (Atomic Force Microscope, AFM), and is an instrument with atomic resolution. The method can be used for detecting physical and chemical properties of a proper sample in the atmosphere, atmosphere or liquid environment or directly performing nano manipulation, and is widely applied to the fields of research and experiments of various nano related disciplines such as semiconductors, biology, chemical industry, food, medicine industry, nano functional materials and the like.
SPM has high requirements on measuring environment, and external interference signals such as vibration, levelness and electromagnetic waves can have certain influence on the measuring result, so that the external signal interference is shielded or reduced, and the quality of the final measuring result can be greatly improved. If the SPM is placed on a non-horizontal workbench in the aspect of levelness, the distance between the final probe tip and the sample platform is gradually changed, so that the measured image result is seriously deviated from the actual situation, and accidents such as sample scratching, even breakage of the probe tip and the like can be caused when the levelness deviation is large.
To reduce the impact of levelness on SPM measurement behavior, numerous forms of levelness adjustment devices have been introduced, such as pneumatic platforms, hydraulic platforms, and the like. For the pneumatic horizontal table, the whole framework is simpler, the cost is lower, but the level of the pneumatic horizontal table is smaller in adjustable range, the pneumatic stability is poorer and is greatly influenced by external pressure, an air pump is additionally required to be added, the air purification treatment in the using process is more complex, impurities and water vapor in an air source are required to be purified, and the air pump has large air charging and discharging noise and produces vibration when working, and can also produce strong interference on the SPM. For the oil pressure horizontal table, the oil is used for bearing pressure, the liquid flow resistance is high, the efficiency is low, the oil cylinder needs to have good sealing performance, the manufacturing precision requirement of the hydraulic element is high, the price is high, the cause is not easy to find when the hydraulic element fails, the use and maintenance requirements have high technical level, and the cleanliness required by the normal working of the SPM cannot be achieved due to the fact that the oil possibly seeps out. In addition, the patent 'an automatically-adjusted table' (202021402996.6) relates to an automatically-adjusted table, but the problems that the price is high, the maintenance is difficult, the cleanliness required by SPM cannot be achieved and the like still exist due to the fact that a sealing ring, a hydraulic pump and a hydraulic foot rod are connected, and the table is mainly used for people with different heights and cannot meet the requirement of a nanoscale scientific research instrument on horizontal precision. The patent (201310379568.4) relates to a novel table body structure of a table top level for a ship, which mainly describes a novel table body structure capable of keeping the level, namely the table body using environment is essentially different from the table body using environment.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide the SPM workbench supporting frame capable of automatically adjusting the levelness, and the supporting frame can meet the requirement of SPM on adjusting the level precision.
In order to achieve the above purpose, the invention adopts a technical scheme that:
The SPM workbench supporting frame capable of automatically adjusting levelness comprises a metal frame and a plurality of sets of pneumatic adjusting mechanisms, wherein the metal frame is of a rectangular frame structure, and each corner of the metal frame is fixedly provided with one set of pneumatic adjusting mechanism;
each set of pneumatic adjusting mechanism comprises a pneumatic rod device, a height sensor and a linkage control system, wherein the pneumatic rod device sequentially comprises an upper upright post, a pneumatic rod and a lower upright post from top to bottom, the upper upright post is connected with one corner of the metal frame, and the upper upright post is connected with the lower upright post through the pneumatic rod;
The height sensor is fixedly arranged on the edge of the metal frame, close to the upper upright post, and is used for measuring the distance between the height sensor and the ground in real time and outputting the distance to the linkage control system in a digital signal form;
The linkage control system can generate a controllable moment with corresponding magnitude according to the digital signal to act on the air rod, and the air rod drives the upper upright post to ascend or descend by corresponding height, so that the levelness of the SPM workbench support frame is automatically adjusted.
Further, as described above, the SPM table support frame with automatically adjustable level, the coordinated control system includes a first signal converter, a first dc motor, a force signal mover, a force detector, a spring, electromagnetic damping, a second signal converter, and a second dc motor.
Further, as described above, the first signal converter and the first dc motor are fixedly disposed on the side of the metal frame near the upper upright post, and the first signal converter is communicatively connected with the height sensor, and is configured to receive a digital signal input by the height sensor, compare a real-time height with a set height value to generate a difference value, convert the difference value into a first controllable current signal, and output the first controllable current signal to the first dc motor, where the output shaft of the first dc motor is connected with a force signal mover, and the first dc motor converts the first controllable current signal into a controllable torque to act on the force signal mover, and then act on the electromagnetic damping-spring through the force signal mover.
Further, the SPM workbench supporting frame capable of automatically adjusting the level is characterized in that the electromagnetic damping and the spring are fixedly arranged on the edge of the metal frame and close to the upper upright post, the spring is connected with the force signal active cell, and under the effect of controllable moment output by the first direct current motor, the electromagnetic damping and the spring can simultaneously move horizontally towards or away from the upper upright post, and in the moving process, the electromagnetic damping-spring generates an inhibiting force resisting movement.
Further, as described above, the SPM table support frame capable of automatically adjusting the level may be communicatively connected to the force signal mover and the spring, for detecting the restraining force generated during the movement of the electromagnetic damping-spring, and outputting the restraining force to the second signal converter in the form of a digital signal.
Further, as described above, the second signal converter and the second dc motor are fixedly disposed in the upper upright, and the second signal converter is communicatively connected to the force detector, and configured to receive the digital signal input by the force detector, convert the digital signal into a second controllable current signal, and output the second controllable current signal to the second dc motor, where the second dc motor converts the second controllable current signal into a controllable torque to act on the air bar, and the air bar drives the upper upright to rise or fall, thereby restoring to the original set height.
Furthermore, the SPM workbench supporting frame capable of automatically adjusting the levelness is further provided with the level meter in the middle of each side of the metal frame, so that the levelness and the adjusting process of the supporting frame can be visually observed.
Further, as described above, the SPM table support frame capable of automatically adjusting the level is provided with a table top on the upper surface of the metal frame, and a rib plate is provided between the upper upright post and the metal frame, for increasing the structural strength of the support frame.
Further, as described above, the SPM table support frame capable of automatically adjusting the level is connected to the lower end of the lower upright post.
Further, as described above, the SPM table support frame capable of automatically adjusting the level is provided with a limit ring on the cylindrical surface of the lower upright, so as to limit the lowest lowering height of the upper upright.
The SPM workbench supporting frame capable of automatically adjusting levelness has the beneficial effects that:
1. The response speed is high. When the table top receives the external force action to cause unbalance, the electromagnetic damping has high propagation speed of electromagnetic waves in the air, and the response time is far lower than that of other means, such as the response time of hydraulic pressure is limited by the flow rate of liquid and the blockage of the liquid caused by unreasonable structural design;
2. the parameter setting is flexible and can be adjusted in a larger range. Because the damping force generated by electromagnetic damping is influenced by a magnetic field, the magnetic field intensity B can be changed to adjust the damping force, and the stiffness coefficient k of the spring can be changed to adjust the damping force;
3. the stability is good, and the damping stability can be improved by controlling the damping ratio;
4. The temperature adaptability is strong, for pneumatic and hydraulic media, gas and liquid, they are greatly affected by temperature, while the electromagnetic force of electromagnetically damped media is much less affected by temperature than gas and liquid.
Drawings
FIG. 1 is a front view of an SPM table support stand with automatically adjustable levelness according to one embodiment;
FIG. 2 is a partial cross-sectional view of the support stand of FIG. 1;
FIG. 3 is a top view of the support stand of FIG. 1;
FIG. 4 is a flow chart illustrating operation of the support stand of FIG. 1;
The device comprises a table top board 1, a rib plate 2, an upper column 3, a gas rod 4, a lower column 5, a 6-universal wheel 7, a level meter 8, a charging port 9, a height sensor 10, a first signal converter 11, a first direct current motor 12, a force signal rotor 13, a force detector 14, a spring 15, electromagnetic damping 16, a second signal converter 17, a second direct current motor 18, a limit ring 19, a power interface 20 and a metal frame.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
Referring to fig. 1 to 4, the SPM workbench supporting frame capable of automatically adjusting levelness provided by the invention mainly comprises a metal frame 20 and four sets of pneumatic adjusting mechanisms, wherein the metal frame 20 is of a rectangular frame structure, and each corner of the metal frame 20 is fixedly provided with one set of pneumatic adjusting mechanism.
Each set of pneumatic adjusting mechanism mainly comprises a pneumatic rod device, a height sensor 9 and a linkage control system, wherein:
Each set of pneumatic rod device sequentially comprises an upper upright post 3, a pneumatic rod 4 and a lower upright post 5 from top to bottom, wherein the upper upright post 3 is connected with one corner of a metal frame 20, the upper upright post 3 is connected with the lower upright post 5 through the pneumatic rod 4, a limit ring 18 is arranged on the cylindrical surface of the lower upright post 5, and the lower end of the lower upright post 5 is connected with a universal wheel 6. The height of the lower upright post 5 is fixed, the height of the upper upright post 3 can be driven and adjusted by the air rod 4, and the lowest height of the upper upright post can be moved to the height of the limit ring 18.
The height sensor 9 is fixedly arranged on the edge of the metal frame 20 near the upper upright post 3, and is used for measuring the distance between the height sensor 9 and the ground in real time and outputting the distance to the linkage control system in a digital signal form. Specifically, the height sensor 9 may be a laser range finder, emits laser to the ground, measures the distance between the height sensor 9 and the ground in real time, and outputs the measured distance in the form of a digital signal.
The coordinated control system comprises a first signal converter 10, a first direct current motor 11, a force signal rotor 12, a force detector 13, a spring 14, an electromagnetic damper 15, a second signal converter 16 and a second direct current motor 17, wherein:
the first signal converter 10 is fixedly arranged on the edge of the metal frame 20 near the upper upright post 3, is in communication connection with the height sensor 9, and is used for receiving digital signals input by the height sensor 9, comparing the real-time height with a set height value to generate a difference value, converting the difference value into a first controllable current signal and outputting the first controllable current signal to the first direct current motor 11. Specifically, the first signal converter 10 converts the digital signal into an electrical signal by using a singlechip and a current amplifier, and then converts the electrical signal into a controllable current signal by using a unidirectional silicon controlled rectifier tube, and outputs the controllable current signal to the first direct current motor 11.
The first direct current motor 11 is fixedly arranged on the edge of the metal frame 20 near the upper upright post 3 and is in communication connection with the first signal converter 10, and an output shaft of the first direct current motor 11 is connected with the force signal rotor 12. The first direct current motor 11 receives the first controllable current signal input by the first signal converter 10, converts the first controllable current signal into a controllable moment to act on the force signal mover 12, and then acts on the electromagnetic damping 15-spring 14 through the force signal mover 12.
The electromagnetic damping 15 and the spring 14 are fixedly arranged on the edge of the metal frame 20 near the upper upright post 3, and the spring 14 is connected with the force signal rotor 12. Under the action of the controllable moment output by the first direct current motor 11, the electromagnetic damping 15 and the spring 14 can horizontally move towards or away from the upper upright post 3 at the same time, and a restraining force resisting the movement is generated inside the electromagnetic damping 15-spring 14 in the moving process.
The force detector 13 is connected to the force signal mover 12 and the spring 14 for detecting a restraining force generated during movement of the electromagnetic damper 15-spring 14 and outputting the restraining force to the second signal converter 16 in the form of a digital signal.
The second signal converter 16 is fixedly arranged in the upper upright 3, is in communication connection with the force detector 13, and is used for receiving the digital signal input by the force detector 13, converting the digital signal into a second controllable current signal and outputting the second controllable current signal to the second direct current motor 17. Specifically, the second signal converter 17 converts the digital signal into an electrical signal by using a singlechip and a current amplifier, and then converts the electrical signal into a controllable current signal by using a unidirectional silicon controlled rectifier tube, and outputs the controllable current signal to the second direct current motor 17.
The second dc motor 17 is fixedly disposed in the upper upright 3, and is in communication connection with the second signal converter 16, and is configured to receive a second controllable current signal input by the second signal converter 16, and convert the second controllable current signal into a controllable torque to act on the air rod 4, where the air rod 4 drives the upper upright 3 to rise or fall, so as to restore to the original set height.
At each corner of the metal frame 20 there is provided a power interface 19 and a charging port 8 for powering the pneumatic adjustment mechanism.
A level meter 7 is arranged in the middle of each side of the metal frame 20, so that the levelness and the adjusting process of the support frame can be visually observed.
A table top 1 is arranged on the upper surface of the metal frame 20, and a rib plate 2 is arranged between the upper upright post 3 and the metal frame 20 for increasing the structural strength of the support frame.
The working principle of the workbench supporting frame capable of automatically adjusting levelness is as follows:
When the upper upright 3 receives force, the height sensor 9 detects the real-time height when the upper upright is lowered from the set height, the digital signal of the real-time height is transmitted to the first signal converter 10, the first signal converter 10 compares the real-time height with the set height to generate a difference value, the difference value is converted into a first current signal to be output, the first current signal is input to the first direct current motor 11 and is converted into a controllable moment, the controllable moment acts on the electromagnetic damping 15-spring 14 through the force signal rotor 12, the moment enables the electromagnetic damping 15-spring 14 to move towards the upright at the same time, the electromagnetic damping 15-spring 14 internally generates an inhibiting force resisting the movement, the inhibiting force is detected by the force sensor 13 and is output to the second signal converter 16, and the second signal converter outputs a second current signal and controls the second direct current motor to generate the controllable moment to act on the air rod 4, so that the upper upright 3 is raised and returns to the original set height.
The following describes the adjustment process of the workbench support frame capable of automatically adjusting levelness by using a specific calculation example.
Assuming that the original height of a certain upright post of the support frame is set to be a meters, the force with the size of x N is added on the upright post, so that the height of the upright post is lowered. The height sensor of the same height of the upright post measures the real-time height b meters between the upright post and the ground in real time and outputs the height b meters to the first signal converter in a digital signal form. In the first signal converter, the real-time height b meter is detected and compared with the original height a meter, and the height difference (a-b) meter is calculated, wherein the height difference (a-b) is in a functional relation with x.
The first signal converter converts the height difference signal into a first current signal and outputs the first current signal to the first direct current motor, and the first direct current motor generates a controllable moment y N and acts on the electromagnetic damping spring. The magnitude of y is now related to the height difference (a-b), i.e. x can be converted into y by conversion.
Under the action of the controllable force y, the electromagnetic damping spring moves towards the upright column at the same time and generates an inhibiting force kN (N) resisting the movement internally, wherein k is related to the electromagnetic damping spring constant coefficient A, B and the controllable force y. The force sensor detects the magnitude of the restraining force k and inputs the restraining force k to the second signal converter.
The second signal converter converts the mechanical digital signal into a second current signal and inputs the second current signal into a second direct current motor, and the direct current motor outputs controllable force z N to act on the air rod, so that the upper upright post rises by b meters and returns to the original set height. At this time, z is related to the restraining force k, the self weight of the upper column, and the like.
The SPM workbench supporting frame capable of automatically adjusting the levelness has the advantages of real-time, gentle and stable adjustment of the levelness, namely, the characteristics of gentle action in the non-horizontal automatic adjustment and stable maintenance after adjustment are detected, and the electromagnetic damping related to the invention has the characteristics of low power consumption, quick response, good fault tolerance, low cost and the like, so that the supporting frame has the advantages of real-time response, stable adjustment process, strong temperature adaptability, low energy consumption, wide adjustment range and the like in the use process, and can better adapt to the requirement of the SPM on the level precision.
The above-described embodiments are merely illustrative of the present invention and are not intended to be all embodiments. The present invention may be embodied in other specific forms or with other specific forms without departing from its spirit or essential characteristics. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims are intended to be encompassed within the scope of the invention.