Cam rotating jacking type mechanism

Abstract

The invention discloses a cam rotating jacking type mechanism. Comprising a mechanical execution module, a man-machine interaction module, a driving control module and a position detection element, the mechanical execution module comprises a conjugate cam and a driven part; the man-machine interaction module comprises a touch display screen; a main controller in the driving control module is in communication connection with the touch display screen and the servo driving unit and is used for outputting a control instruction to the servo driving unit according to an obtained user input instruction; the servo driving unit is used for outputting a driving current to the servo motor according to the control instruction; the encoder is arranged at the motor shaft end of the servo motor and is used for transmitting obtained motor shaft position information to the main controller; the position detection element is in communication connection with the main controller and is used for transmitting the obtained jacking position information of the jacking platform to the main controller; the main controller is further used for adjusting a control instruction output to the servo driving unit according to the motor shaft position information and the jacking position information. And the jacking control precision can be improved.

Description

Technical Field

[0001] This invention relates to the field of lifting mechanism technology, and more particularly to a cam-rotating lifting mechanism. Background Technology

[0002] In automated production lines and precision assembly equipment, such as equipment used in display panel coating and developing processes, cam-driven lifting mechanisms are crucial. These mechanisms enable intermittent lifting and rotational positioning of workpieces, their core function being the conversion of the cam's rotational motion into precise linear lifting motion of the actuator. Currently, the mainstream control scheme for cam-driven lifting mechanisms in the industry primarily employs a traditional PLC open-loop control mode. This system typically consists of a standard asynchronous motor, a gearbox, a mechanical cam assembly, and limit switches.

[0003] Taking an electronic component assembly line as an example, the specific technical solution adopted is as follows: a Mitsubishi FX3U series PLC sends fixed pulse commands to control the rotation of an asynchronous motor. The motor drives an eccentric cam to rotate via a gearbox. When the cam profile contacts the driven component, a lifting action is achieved. A limit switch detects the lifting limit position and triggers the motor to stop. This solution accounts for more than 60% of the applications in small and medium-sized automated equipment in China.

[0004] The existing technical solutions have the following significant drawbacks:

[0005] 1. Insufficient positioning accuracy: Due to the use of open-loop control and the lack of position feedback in the asynchronous motor, the actual lifting repeatability positioning error is generally above ±0.15mm, which cannot meet the assembly requirements of precision products such as 5G communication components (typically requiring ±0.05mm). Actual measurement data from a certain automotive electronic component production line shows that the positioning deviation of the cam mechanism using the traditional solution can reach 0.23mm after 8 hours of continuous operation.

[0006] 2. Severe response lag: The trigger response time of the mechanical limit switch is >50ms, which easily leads to overshoot during high-speed operation (cam speed >300rpm). In mobile phone screen bonding equipment, this lag can increase the lamination misalignment rate of the glass substrate to 1.2%. Summary of the Invention

[0007] This invention provides a cam-rotating lifting mechanism to solve the problems of insufficient positioning accuracy and severe response lag in existing cam-rotating lifting mechanisms.

[0008] This invention provides a cam-driven rotary lifting mechanism, including a mechanical execution module, a human-machine interaction module, a drive control module, and a position detection element disposed on a lifting platform;

[0009] The mechanical actuation module includes a conjugate cam and a follower; the conjugate cam and the follower are in constant contact, and when the conjugate cam rotates, the follower moves in a linear motion; the follower is fixedly connected to the lifting platform.

[0010] The human-computer interaction module includes a touch screen; the touch screen is used to acquire user input commands.

[0011] The drive control module includes a main controller, a servo drive unit, a servo motor, a gearbox, and an encoder;

[0012] The main controller is communicatively connected to the touch screen and the servo drive unit, respectively, and is used to acquire the user input command and output control command to the servo drive unit according to the user input command;

[0013] The servo drive unit is electrically connected to the servo motor and is used to output drive current to the servo motor according to the control command, so as to control the rotation of the servo motor;

[0014] The gearbox is connected between the servo motor and the conjugate cam, and is used to convert the first speed and the first torque output by the servo motor into the second speed and the second torque required by the conjugate cam, so as to provide power for the rotation of the conjugate cam, wherein the first speed is greater than the second speed and the first torque is less than the second torque;

[0015] The encoder is installed on the motor shaft end of the servo motor and is communicatively connected to the main controller. It is used to acquire motor shaft position information and transmit the motor shaft position information to the main controller.

[0016] The position detection element is communicatively connected to the main controller and is used to acquire the lifting position information of the lifting platform and transmit the lifting position information to the main controller.

[0017] The main controller is also used to adjust the control commands output to the servo drive unit according to the motor shaft position information and the lifting position information.

[0018] Optionally, the encoder is also used to acquire motor shaft speed information and transmit the motor shaft speed information to the main controller;

[0019] The main controller is also used to determine the movement speed of the driven member based on the motor shaft speed information, and transmit the movement speed to the touch screen; the touch screen displays the movement speed.

[0020] Optionally, the main controller is further configured to control the servo drive unit to stop outputting drive current to the servo motor when the time without receiving the user input command exceeds a preset time.

[0021] Optionally, the conjugate cam includes a master cam and a return cam;

[0022] The surface roughness Ra1 of the main cam satisfies: Ra1≤0.8μm;

[0023] The surface roughness Ra2 of the return cam satisfies: Ra2≤0.8μm.

[0024] Optionally, the driven member includes a roller bearing;

[0025] The roller bearing is located at the contact end between the follower and the conjugate cam.

[0026] Optionally, the encoder includes a 17-bit absolute encoder.

[0027] Optionally, the gearbox may include a planetary gearbox.

[0028] Optionally, the user input command includes a preset cam motion curve.

[0029] Optionally, the main controller is connected to the servo drive unit via an EtherCAT bus.

[0030] Optionally, the travel range of the lifting platform is 0-50mm.

[0031] The technical solution of this invention embodiment is that by setting the main controller to adjust the control commands output to the servo drive unit according to the motor shaft position information and the lifting position information, the drive current output by the servo drive unit to the drive motor is changed until the theoretical lifting position information determined according to the motor shaft position information is consistent with the lifting position information obtained from the position detection element. This combines the position information fed back by the encoder located at the servo motor with the actual position information of the lifting platform to form a position-position dual closed-loop control system. This not only improves the response and achieves 10ms-level dynamic adjustment, but also improves the positioning accuracy compared to the traditional single closed-loop system.

[0032] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of a cam-rotating lifting mechanism provided in an embodiment of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices. The terms "upper," "lower," "left," "right," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings and are only used to describe the relative positional relationships between components or constituent parts, and do not specifically limit the specific installation orientation of each component or constituent part.

[0037] Figure 1 This is a schematic diagram of a cam-rotating lifting mechanism provided in an embodiment of the present invention, with reference to... Figure 1 The cam rotation lifting mechanism in this embodiment of the invention includes a mechanical execution module 10 and a human-machine interaction module (…). Figure 1 (Not shown in the image), drive control module 20, and position detection element mounted on lifting platform 200. Figure 1(Not shown in the image); the mechanical actuation module 10 includes a conjugate cam 11 and a follower 12; the conjugate cam 11 and the follower 12 are in constant contact, and when the conjugate cam 11 rotates, the follower 12 moves linearly; the follower 12 is fixedly connected to the lifting platform 200; the human-machine interaction module includes a touch screen; the touch screen is used to acquire user input commands; the drive control module 20 includes a main controller ( Figure 1 (not shown in the image), servo drive unit ( Figure 1 The system comprises a servo motor 21, a gearbox 22, and an encoder 23 (not shown in the diagram). The main controller is communicatively connected to both the touchscreen display and the servo drive unit to acquire user input commands and output control commands to the servo drive unit based on these commands. The servo drive unit is electrically connected to the servo motor 21 and outputs drive current to the servo motor 21 according to the control commands to control its rotation. The gearbox 22 is connected between the servo motor 21 and the conjugate cam 11 to convert the first speed and first torque output by the servo motor 21 into the second speed and second torque required by the conjugate cam 11, providing power for the rotation of the conjugate cam 11, wherein the first speed is greater than the second speed and the first torque is less than the second torque. The encoder 23 is located on the motor shaft end of the servo motor 21 and is communicatively connected to the main controller to acquire motor shaft position information and transmit it to the main controller. The position detection element is communicatively connected to the main controller to acquire the lifting position information of the lifting platform 200 and transmit it to the main controller. The main controller is also used to adjust the control commands output to the servo drive unit based on the motor shaft position information and the lifting position information.

[0038] For example, the conjugate cam 11 in this embodiment of the invention can be made of 45# steel. In a specific embodiment, the conjugate cam 11 in this embodiment of the invention includes a main cam and a return cam; the surface roughness Ra1 of the main cam satisfies: Ra1≤0.8μm; the surface roughness Ra2 of the return cam satisfies: Ra2≤0.8μm.

[0039] Specifically, the surface roughness of the main cam and the return cam can be achieved by precision grinding. In this embodiment of the invention, by setting the surface roughness of the main cam and the return cam to be less than or equal to 0.8 μm, the contact friction between the conjugate cam 11 and the follower 12 can be reduced, wear can be decreased, and transmission accuracy and stability can be ensured. This, in turn, helps to improve the smoothness of operation and service life of the cam rotation lifting mechanism.

[0040] The touch screen in this embodiment of the invention can be a 10.1-inch (1024×600 resolution) touch screen, and a dedicated control interface can be developed with the following functions: users can input control commands through the touch screen, such as raising the lifting platform 200 by 20mm, etc.

[0041] In this embodiment of the invention, the main controller can be a PLC (Programmable Logic Controller). The main controller can have a built-in 200kHz high-speed pulse output channel and an EtherCAT industrial Ethernet interface (communication cycle ≤1ms), and can support the PLCopen motion control specification.

[0042] In this embodiment of the invention, the servo motor 21 can be a motor with a rated speed of 3000 rpm.

[0043] The encoder 23 in this embodiment of the invention includes a 17-bit absolute encoder 23. The resolution of the 17-bit absolute encoder 23 can reach 131072ppr.

[0044] The reduction gearbox 22 in this embodiment of the invention includes a planetary reduction gearbox 22. The transmission ratio of the planetary reduction gearbox 22 can be 1:5.

[0045] This invention, through its embodiment, enables the main controller to adjust the control commands output to the servo drive unit based on the motor shaft position information and the lifting position information. This, in turn, changes the drive current output from the servo drive unit to the drive motor, until the theoretical lifting position information determined based on the motor shaft position information matches the lifting position information obtained from the position detection element. This allows the position information fed back by the encoder 23 located at the servo motor 21 to be combined with the actual position information of the lifting platform 200, forming a position-position dual closed-loop control system. This not only improves the response and achieves 10ms-level dynamic adjustment but also enhances the positioning accuracy compared to traditional single closed-loop systems.

[0046] Based on the above embodiments, the encoder 23 in this embodiment of the invention is also used to acquire motor shaft speed information and transmit the motor shaft speed information to the main controller; the main controller is also used to determine the movement speed of the driven member 12 according to the motor shaft speed information and transmit the movement speed to the touch screen; the touch screen displays the movement speed.

[0047] In this embodiment of the invention, the main controller is also used to transmit the lifting position information to the touch screen, which can display the lifting position information.

[0048] Optionally, the main controller is also used to control the servo drive unit to stop outputting drive current to the servo motor 21 when the time without receiving user input instructions exceeds a preset time.

[0049] For example, if the main controller does not receive a new user input command for more than 30 seconds after executing the previous command, it will control the servo drive unit to stop outputting drive current to the servo motor 21 to automatically switch to servo sleep mode. At this time, the power consumption of the entire mechanism can be reduced to less than 0.5W, which saves 52% energy compared to the traditional asynchronous motor solution.

[0050] In one feasible implementation, the follower 12 in this embodiment of the invention includes a roller bearing; the roller bearing is disposed at the contact end between the follower 12 and the conjugate cam 11.

[0051] By setting the follower 12 to contact the cam mechanism through a roller bearing, the sliding friction between the cam and the follower 12 can be converted into rolling friction, which is beneficial to improving the transmission performance of the conjugate cam 11 and the follower 12.

[0052] In one possible implementation, the user input command includes a preset cam motion curve.

[0053] For example, in this embodiment of the invention, the touch screen develops a dedicated control interface with the following functions: it can provide a parameterized setting interface for cam curves, support curve preview and offline simulation, internally store 100 sets of process recipes, and can realize one-click model change.

[0054] After the main controller obtains the preset cam motion curve selected by the user through the touch screen, it can use the PLC's CAM table function to realize the software definition of the cam motion curve. It should be noted that the PLC's CAM table function essentially replaces the traditional mechanical cam mechanism by configuring software parameters. The motion relationship between the master and slave shafts (displacement-displacement, displacement-time, speed-displacement, etc. mapping relationships) is stored in the PLC in the form of a data table. During operation, the PLC can call the corresponding data in real time according to the obtained preset cam motion curve and output the corresponding control commands to the servo drive unit. Then, the servo drive unit can output the drive current that can realize the preset cam motion curve to the servo motor 21 to achieve precise cam linkage, replacing the physical contour of the traditional mechanical cam. By modifying the electronic gear ratio parameter (adjustable in the range of 1:1-1:100), the lifting stroke can be infinitely adjusted, and the changeover efficiency is improved by 87.5%.

[0055] Optionally, in this embodiment of the invention, the main controller can also transmit the acquired historical fault records (including timestamps and fault codes) to the touch screen, which can store the received historical fault records and support users to query the most recent 100 fault information records.

[0056] In one feasible implementation, the main controller is connected to the servo drive unit via an EtherCAT bus.

[0057] This invention employs an EtherCAT bus to achieve high-speed data transmission between the main controller and the servo drive unit, with communication jitter ≤100ns, ensuring precise synchronization of control commands even at a high speed of 600rpm.

[0058] In one feasible implementation, the travel range of the lifting platform 200 in this embodiment of the invention is 0-50mm.

[0059] It should be noted that the travel range of the lifting platform 200 in this embodiment of the invention is adjustable.

[0060] Optionally, the maximum lifting load of the driven member 12 in this embodiment of the invention is 50 kgf.

[0061] Through practical application verification on a precision connector assembly production line (running continuously for 30 days), the present invention can achieve the following technical effects:

[0062] 1. Accuracy indicators: The lifting repeatability accuracy reaches ±0.028mm (3σ), which is 81.3% higher than the background technology, meeting the mounting requirements of 01005 specification chips;

[0063] 2. Speed ​​performance: Under the condition of cam speed of 600rpm, the system response time is stable at 8ms with no overshoot, and the equipment production efficiency is improved by 50%;

[0064] 3. Debugging efficiency: When changing product models, only process parameters need to be modified via touch screen, with an average debugging time of 22 minutes, saving 91.7% of man-hours compared to traditional mechanical adjustment methods;

[0065] 4. Reduced energy consumption: Through servo sleep mode and dynamic power adjustment, the average energy consumption of the equipment is reduced from 3.2kW to 1.5kW, saving approximately 15,120 kWh per year (based on 300 days of operation per year and 16 hours per day).

[0066] 5. Failure rate: Mechanical failure interval (MTBF) increased from 1200 hours to 4500 hours, and maintenance costs decreased by 65%.

[0067] The comparison data with existing technologies is shown in Table 1 below:

[0068] Table 1

[0069]

[0070] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A cammed rotary jacking mechanism, characterized by, The mechanical execution module, the human-computer interaction module, the drive control module and the position detection element arranged on the jacking platform are included. The mechanical execution module includes a conjugate cam and a follower; the conjugate cam is in constant contact with the follower; when the conjugate cam rotates, the follower moves linearly; the follower is fixedly connected with the jacking platform. The human-computer interaction module includes a touch display screen; the touch display screen is used for obtaining a user input instruction. The drive control module includes a main controller, a servo drive unit, a servo motor, a reduction box and an encoder. The main controller is in communication connection with the touch display screen and the servo drive unit respectively, is used for obtaining the user input instruction, and outputs a control instruction to the servo drive unit according to the user input instruction. The servo drive unit is electrically connected with the servo motor, is used for outputting a drive current to the servo motor according to the control instruction, so as to control the servo motor to rotate. The reduction box is connected between the servo motor and the conjugate cam, is used for converting a first rotating speed and a first torque output by the servo motor into a second rotating speed and a second torque required by the conjugate cam, and provides power for the rotation of the conjugate cam, wherein the first rotating speed is greater than the second rotating speed, and the first torque is less than the second torque. The encoder is arranged at a motor shaft end of the servo motor, and is in communication connection with the main controller, is used for obtaining motor shaft position information, and transmits the motor shaft position information to the main controller. The position detection element is in communication connection with the main controller, is used for obtaining jacking position information of the jacking platform, and transmits the jacking position information to the main controller. The main controller is further used for adjusting the control instruction output to the servo drive unit according to the motor shaft position information and the jacking position information.

2. The cammed rotary lift mechanism of claim 1, wherein, The encoder is further used for obtaining motor shaft speed information, and transmits the motor shaft speed information to the main controller. The main controller is further used for determining a movement speed of the follower according to the motor shaft speed information, and transmits the movement speed to the touch display screen; the touch display screen displays the movement speed.

3. The cammed rotary lift mechanism of claim 1 wherein, The main controller is further used for controlling the servo drive unit to stop outputting the drive current to the servo motor when a time of not receiving the user input instruction exceeds a preset time.

4. The cammed rotary lift mechanism of claim 1 wherein, The conjugate cam includes a main cam and a return cam. A surface roughness Ra1 of the main cam satisfies: Ra1≤0.8 μm. A surface roughness Ra2 of the return cam satisfies: Ra2≤0.8 μm.

5. The cammed rotary lift mechanism of claim 1 wherein, The follower includes a roller bearing. The roller bearing is arranged at a contact end of the follower and the conjugate cam.

6. The cammed rotary lift mechanism of claim 1 wherein, The encoder includes a 17-bit absolute value encoder.

7. The cammed rotary lift mechanism of claim 1 wherein, The reduction box includes a planetary reduction box.

8. The cammed rotary lift mechanism of claim 1 wherein, The user input instruction includes a preset cam movement curve.

9. The cammed rotary lift mechanism of claim 1 wherein, The main controller is in communication connection with the servo drive unit through an EtherCAT bus.

10. The cammed rotary lift mechanism of claim 1 wherein, A stroke range of the jacking platform is 0-50 mm.

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