A multi-stage coordinated synchronous hydraulic cylinder and its intelligent control method

Abstract

The present invention discloses a multi-stage coordinated synchronous hydraulic cylinder and its intelligent control method, including: a base, a hydraulic cylinder bottom fixing device is fixedly connected to the top end of the base, a clamping device is arranged on the side end of the hydraulic cylinder bottom fixing device, the clamping device is fixedly connected to the base, a support frame is arranged on the side end of the clamping device, the support frame is fixedly connected to the top end of the base, a lifting platform is clamped at the top end of the support frame, a multi-stage hydraulic cylinder is arranged between the lifting platform and the hydraulic cylinder bottom fixing device, the bottom end of the multi-stage hydraulic cylinder is clamped with the hydraulic cylinder bottom fixing device, and the top end of the multi-stage hydraulic cylinder is clamped with the lifting platform; in the present invention, by starting the clamping hydraulic rod, the synchronous plate can be driven to push downward, so that the fixed convex platform moves downward, realizing the clamping and fixing of the bottom end of the hydraulic cylinder, ensuring the synchronous movement of the bottom ends of the hydraulic cylinders in the multi-stage hydraulic cylinder system, and thus ensuring the stability and balance of the working platform or equipment during the lifting or moving process.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic cylinder equipment, and specifically relates to a multi-stage coordinated synchronous hydraulic cylinder and its intelligent control method. Background Art

[0002] A hydraulic cylinder is a device that converts hydraulic energy into mechanical energy. When hydraulic oil is pumped into the cylinder, the pressure of the hydraulic oil acts on the piston, pushing the piston to move along the inside of the cylinder, thereby driving the piston rod to do work. A multi-stage hydraulic cylinder is usually composed of multiple sets of piston rods arranged in a set of cylinders. A multi-stage synchronous hydraulic cylinder refers to the synchronous control of multiple sets of multi-stage hydraulic cylinders. Multi-stage synchronous hydraulic cylinders are usually applied to engineering scenarios that require high force output and precise control, such as hydraulic lifting platforms. In scenarios where heavy objects need to be lifted, positioned, or the height adjusted, multi-stage synchronous hydraulic cylinders can provide stable lifting force and ensure the synchronism of each lifting point, thereby improving work efficiency and safety.

[0003] Most of the existing multi-stage synchronous hydraulic cylinders are installed by fixing multiple sets of hydraulic cylinders one by one at the lower end of the lifting platform and using screws for fixation. However, such an installation process is too cumbersome, and there will be problems such as difficult debugging and inconvenient maintenance in the later stage. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-stage synchronous hydraulic cylinder and its intelligent control method to solve the problem that most of the existing multi-stage synchronous hydraulic cylinders are installed by fixing multiple sets of hydraulic cylinders one by one at the lower end of the lifting platform and using screws for fixation, but such an installation process is too cumbersome, and there will be problems such as difficult debugging and inconvenient maintenance in the later stage.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A multi-stage coordinated synchronous hydraulic cylinder and its intelligent control method, including: a base, a hydraulic cylinder bottom fixing device is fixedly connected to the top of the base, a clamping device is arranged on the side of the hydraulic cylinder bottom fixing device, the clamping device is fixedly connected to the base, a support frame is arranged on the side of the clamping device, the support frame is fixedly connected to the top of the base, a lifting platform is clamped at the top of the support frame, a multi-stage hydraulic cylinder is arranged between the lifting platform and the hydraulic cylinder bottom fixing device, the bottom of the multi-stage hydraulic cylinder is clamped to the hydraulic cylinder bottom fixing device, and the top of the multi-stage hydraulic cylinder is clamped to the lifting platform;

[0006] The clamping device includes a linear driver, a clamping motor, a clamping gear, an L-shaped fixing block, a clamping rack, a rack fixing block, and a rack fixing groove;

[0007] The multi-stage hydraulic cylinder includes a hydraulic cylinder main body, an upper fixing block, a lower fixing block, an installation groove, and a positioning sensor;

[0008] The bottom fixing device of the hydraulic cylinder includes a fixed convex platform, a connecting rod, a synchronous plate and a clamping hydraulic rod;

[0009] The support frame includes an L-shaped support rod and a C-shaped limiting frame.

[0010] As a further solution of the present invention: The linear drive includes a fixed frame, a lead screw, a slide rail, a moving block and a moving motor.

[0011] As a further solution of the present invention: The fixed frame is fixedly connected to the base. The lead screw is arranged at the inner end of the fixed frame, penetrates through the fixed frame and is rotatably connected to the fixed frame. There are two groups of slide rails, symmetrically distributed on both sides of the lead screw and fixedly connected to the fixed frame. The moving block is threadedly connected to the lead screw and slidably connected to the slide rail. The moving motor is fixedly connected to the side end of the fixed frame, and the output end of the moving motor is fixedly connected to the lead screw. There are two groups of linear drives, symmetrically distributed on the top of the base.

[0012] As a further solution of the present invention: The clamping motor is fixedly connected to a group of moving blocks. The output end of the clamping motor is fixedly connected to the clamping gear. The side end of the clamping gear is meshed with the clamping rack. The clamping rack is arranged at the inner end of the L-shaped fixed block. The L-shaped fixed block is fixedly connected to the clamping motor. The rack fixed block is fixedly connected to the other group of moving blocks. The rack fixed groove is opened at the top of the rack fixed block. The clamping rack is inserted into the rack fixed groove. There are two groups of clamping devices, rotationally symmetrically distributed on the top of the two groups of moving blocks. The distance between the two groups of clamping racks is the same as the diameter of the multi-stage hydraulic cylinder.

[0013] As a further solution of the present invention: The movable top end of the hydraulic cylinder body is fixedly connected to the upper fixed clamp block, and the bottom end of the hydraulic cylinder body is fixedly connected to the lower fixed clamp block. The installation groove is opened at the bottom end of the lower fixed clamp block. The positioning sensor is arranged at the inner end of the installation groove and fixedly connected to the lower fixed clamp block. There are multiple groups of hydraulic cylinder bodies.

[0014] As a further solution of the present invention: There are multiple groups of fixed convex platforms. Every two groups are symmetrically distributed on both sides of a column of multi-stage hydraulic cylinders. Each group of lower fixed clamp blocks is clamped with two groups of fixed convex platforms. There are multiple groups of connecting rods. The connecting rods penetrate through the base. The top end of the connecting rod is fixedly connected to the fixed convex platform, and the bottom end is fixedly connected to the synchronous plate. There are four groups of clamping hydraulic rods, symmetrically distributed on the top of the synchronous plate. The fixed end of the clamping hydraulic rod is fixedly connected to the bottom end of the base, and the movable end of the clamping hydraulic rod is fixedly connected to the top of the synchronous plate.

[0015] As a further solution of the present invention: Four groups of L-shaped support rods are provided, symmetrically distributed on both sides of the lifting platform. Two groups of L-shaped support rods on the same side are fixedly connected to a group of C-shaped limit frames, and the C-shaped limit frames are clamped with the lifting platform.

[0016] As a further solution of the present invention: The lifting platform includes a platform body and fixed clamping grooves.

[0017] As a further solution of the present invention: Multiple groups of fixed clamping grooves are provided, evenly opened at the bottom end of the platform body, and the upper fixed clamping blocks are clamped with the fixed clamping grooves.

[0018] As an intelligent control method of the present invention, it includes the following steps:

[0019] S1. First, arrange multiple groups of multi-stage hydraulic cylinders in a row, place the lower fixed clamping blocks at their bottom ends between multiple groups of fixed convex platforms, insert the upper fixed clamping blocks at their top ends into the fixed clamping grooves, and start the moving motor to drive the screw rod to rotate, so that the moving block moves along the direction of the slide rail to the side end of the multi-stage hydraulic cylinder. Then, drive the clamping gear to rotate through the clamping motor, so that one end of the clamping rack is inserted into the rack fixing groove at the top end of the rack fixing block. At this time, the two clamping racks are in contact with multiple groups of multi-stage hydraulic cylinders arranged in a row to clamp the multi-stage hydraulic cylinders.

[0020] S2. Then, use the linear actuator again to move the clamped multiple groups of multi-stage hydraulic cylinders to the bottom end of the lifting platform. Repeat the operation to place multiple rows of multi-stage hydraulic cylinders between the bottom fixing device of the hydraulic cylinder and the lifting platform, and control the spacing of the multi-stage hydraulic cylinders in each row through the positioning sensors at the bottom ends of the multi-stage hydraulic cylinders to make the multi-stage hydraulic cylinders evenly distributed.

[0021] S3. Finally, start the clamping hydraulic rod to push the synchronous plate downward, drive the fixed convex platform to move downward, and reduce the distance between the fixed convex platform and the base to clamp and fix the lower fixed clamping block.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. In the present invention, by starting the clamping hydraulic rod, the synchronous plate can be driven to move downward, so that the fixed convex platform moves downward, realizing the clamping and fixing of the bottom end of the hydraulic cylinder, ensuring the synchronous movement of the bottom ends of the hydraulic cylinders in the multi-stage hydraulic cylinder system, and thus ensuring the stability and balance of the working platform or equipment during lifting or moving.

[0024] 2. In the present invention, the upper fixing block and the lower fixing block make the installation and adjustment of the hydraulic cylinder more convenient and rapid. The operator can adjust the position of the hydraulic cylinder according to needs to adapt to different working scenarios and requirements, improving the flexibility and applicability of the system. By using the positioning sensor to monitor and feedback the position of the hydraulic cylinder body, precise control of the hydraulic cylinder position can be achieved, ensuring the synchronous movement and positioning accuracy of the multi-stage hydraulic cylinder, and improving the working efficiency and accuracy of the system.

[0025] 3. In the present invention, the C-shaped limiting frame can limit the movement range of the lifting platform, ensuring its operation within a safe position, preventing the lifting platform from moving when the multi-stage hydraulic cylinder is installed, causing the lifting platform to shift, resulting in abnormal position changes or instability during the lifting of the lifting platform, thus ensuring the safe operation of the multi-stage hydraulic cylinder and the stability of the lifting platform.

[0026] 4. Improve the robustness and adaptability of the multi-stage synchronous hydraulic cylinder system: The fuzzy PID controller has good robustness and can handle the nonlinearity and uncertainty of the hydraulic cylinder system. In the multi-stage synchronous hydraulic cylinder system, the position and speed of the hydraulic cylinders may exhibit complex dynamic changes. The DDPG algorithm can learn these complex dynamics and respond to these changes by optimizing the control strategy. Combining the two ensures that the hydraulic cylinder system can maintain stability under various working conditions and adapt to changes in the system state.

[0027] 5. Enhance the real-time response ability of the multi-stage synchronous hydraulic cylinder system: The fuzzy PID controller generates control signals based on the real-time system state and error, and can quickly respond to changes in the position and speed of the hydraulic cylinder. When the position of a certain hydraulic cylinder deviates, the fuzzy PID controller can immediately generate a correction signal. Combining with the DDPG algorithm, the real-time response ability of the system can be improved through continuous learning and optimization, making the hydraulic cylinder system more flexible and efficient in actual operation.

[0028] 6. Optimize the long-term control strategy of the multi-stage synchronous hydraulic cylinder system: The DDPG algorithm can find the optimal control strategy for the hydraulic cylinder system by continuously learning and adjusting network parameters to maximize the long-term reward. Through continuous optimization, it can ensure that the hydraulic cylinders always remain synchronous during long-term operation, reduce problems such as position deviation and speed inconsistency, and improve the long-term performance and stability of the system.

[0029] 7. Improve the control accuracy and efficiency of the multi-stage synchronous hydraulic cylinder system: The fuzzy PID controller combines empirical rules and fuzzy inference, which can improve the control accuracy. By designing a suitable fuzzy rule base, the position and speed of the hydraulic cylinder can be accurately adjusted. The DDPG algorithm can search for the optimal solution in the continuous action space, further improving the control efficiency and accuracy. The combination of the two enables the hydraulic cylinder system to achieve high-precision and high-efficiency control under various operating conditions.

[0030] 8. Reduce the maintenance cost of the multi-stage synchronous hydraulic cylinder system: Combining the fuzzy PID controller and the DDPG algorithm can make the hydraulic cylinder system more stable and reliable, reducing the maintenance cost and risk. By continuously optimizing the control strategy, the frequent adjustment and maintenance requirements for the system are reduced, improving the stability and reliability of the system. This stability reduces the wear and failure frequency of the equipment, thus reducing the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the overall structural schematic diagram of a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0032] Figure 2 is the structural schematic diagram of the multi-stage hydraulic cylinder in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0033] Figure 3 is the structural schematic diagram of the clamping device in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0034] Figure 4 is the structural schematic diagram of the linear actuator in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0035] Figure 5 is the structural schematic diagram of the position A in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0036] Figure 6 is the structural schematic diagram of the position B in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0037] Figure 7 is the structural schematic diagram of the support frame in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0038] Figure 8 is the structural schematic diagram of the fixed device at the bottom end of the hydraulic cylinder in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention;

[0039] Figure 9It is a schematic structural diagram of the C position in a multi-stage synchronous hydraulic cylinder and its intelligent control method according to the present invention.

[0040] Figure 10 It is a flowchart of an intelligent algorithm that introduces a fuzzy PID controller and combines it with the Deep Deterministic Policy Gradient (DDPG) algorithm for a multi-stage synchronous hydraulic cylinder according to the present invention.

[0041] In the figure: 1. Base; 2. Clamping device; 21. Linear driver; 211. Fixed frame; 212. Lead screw; 213. Slide rail; 214. Moving block; 215. Moving motor; 22. Clamping motor; 23. Clamping gear; 24. L-shaped fixing block; 25. Clamping rack; 26. Rack fixing block; 27. Rack fixing groove; 3. Multi-stage hydraulic cylinder; 31. Hydraulic cylinder body; 32. Upper fixing clamp; 33. Lower fixing clamp; 34. Installation groove; 35. Positioning sensor; 4. Hydraulic cylinder bottom fixing device; 41. Fixed convex platform; 42. Connecting rod; 43. Synchronous plate; 44. Clamping hydraulic rod; 5. Support frame; 51. L-shaped support rod; 52. C-shaped limit frame; 6. Lifting table; 61. Table body; 62. Fixed card slot. Specific implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. The embodiments of the present invention will be described below according to its overall structure.

[0044] Referring to Figure 1 , in the embodiment of the present invention, a multi-stage synchronous hydraulic cylinder and its intelligent control method include: a base 1, a hydraulic cylinder bottom fixing device 4 is fixedly connected to the top end of the base 1, a clamping device 2 is arranged on the side end of the hydraulic cylinder bottom fixing device 4, the clamping device 2 is fixedly connected to the base 1, a support frame 5 is arranged on the side end of the clamping device 2, the support frame 5 is fixedly connected to the top end of the base 1, a lifting platform 6 is clamped to the top end of the support frame 5, a multi-stage hydraulic cylinder 3 is arranged between the lifting platform 6 and the hydraulic cylinder bottom fixing device 4, the bottom end of the multi-stage hydraulic cylinder 3 is clamped to the hydraulic cylinder bottom fixing device 4, and the top end of the multi-stage hydraulic cylinder 3 is clamped to the lifting platform 6.

[0045] Referring to Figures 3 to 6, the clamping device 2 includes a linear driver 21, a clamping motor 22, a clamping gear 23, an L-shaped fixing block 24, a clamping rack 25, a rack fixing block 26 and a rack fixing groove 27. The linear driver 21 includes a fixing frame 211, a lead screw 212, a slide rail 213, a moving block 214 and a moving motor 215. The fixing frame 211 is fixedly connected to the base 1. The lead screw 212 is arranged at the inner end of the fixing frame 211, penetrates through the fixing frame 211 and is rotatably connected to the fixing frame 211. There are two groups of slide rails 213, symmetrically distributed on both sides of the lead screw 212 and fixedly connected to the fixing frame 211. The moving block 214 is threadedly connected to the lead screw 212 and slidably connected to the slide rail 213. The moving motor 215 is fixedly connected to the side end of the fixing frame 211, and the output end of the moving motor 215 is fixedly connected to the lead screw 212. There are two groups of linear drivers 21, symmetrically distributed at the top of the base 1. The clamping motor 22 is fixedly connected to one group of moving blocks 214, and the output end of the clamping motor 22 is fixedly connected to the clamping gear 23. The side end of the clamping gear 23 is meshed with the clamping rack 25. The clamping rack 25 is arranged at the inner end of the L-shaped fixing block 24, and the L-shaped fixing block 24 is fixedly connected to the clamping motor 22. The rack fixing block 26 is fixedly connected to the other group of moving blocks 214. The rack fixing groove 27 is opened at the top of the rack fixing block 26, and the clamping rack 25 is inserted into the rack fixing groove 27. There are two groups of clamping devices 2, rotationally symmetrically distributed at the top of the two groups of moving blocks 214. The distance between the two groups of clamping racks 25 is the same as the diameter of the multi-stage hydraulic cylinder 3.

[0046] With the above solution: Through the cooperation of the clamping motor 22 and the linear driver 21, the clamping device 2 can achieve automated operation, improve the operation efficiency and accuracy, and reduce the error of manual operation.

[0047] Refer to Figure 2 , the multi-stage hydraulic cylinder 3 includes a hydraulic cylinder main body 31, an upper fixing block 32, a lower fixing block 33, an installation groove 34 and a positioning sensor 35. The movable top end of the hydraulic cylinder main body 31 is fixedly connected to the upper fixing block 32, and the bottom end of the hydraulic cylinder main body 31 is fixedly connected to the lower fixing block 33. The installation groove 34 is opened at the bottom end of the lower fixing block 33, and the positioning sensor 35 is arranged at the inner end of the installation groove 34 and fixedly connected to the lower fixing block 33. There are multiple groups of hydraulic cylinder main bodies 31.

[0048] With the above solution: Through the upper fixing block 32 and the lower fixing block 33, the installation and adjustment of the hydraulic cylinder are more convenient and fast. The operator can adjust the position of the hydraulic cylinder according to needs to adapt to different working scenarios and requirements, improving the flexibility and applicability of the system. By monitoring and feedback of the positioning sensor 35 on the position of the hydraulic cylinder main body 31, precise control of the position of the hydraulic cylinder can be achieved, ensuring the synchronous movement and positioning accuracy of the multi-stage hydraulic cylinder 3, and improving the working efficiency and accuracy of the system.

[0049] Referring to Figures 8 to 9 Figure, the fixing device 4 at the bottom end of the hydraulic cylinder includes a fixing convex platform 41, a connecting rod 42, a synchronous plate 43 and a clamping hydraulic rod 44. There are multiple groups of fixing convex platforms 41, and every two groups are symmetrically distributed on both sides of a column of multi-stage hydraulic cylinders 3. Each group of lower fixing blocks 33 is clamped with two groups of fixing convex platforms 41. There are multiple groups of connecting rods 42. The connecting rods 42 penetrate through the base 1. The top end of the connecting rod 42 is fixedly connected to the fixing convex platform 41, and the bottom end is fixedly connected to the synchronous plate 43. There are four groups of clamping hydraulic rods 44, which are symmetrically distributed at the top end of the synchronous plate 43. The fixed end of the clamping hydraulic rod 44 is fixedly connected to the bottom end of the base 1, and the movable end of the clamping hydraulic rod 44 is fixedly connected to the top end of the synchronous plate 43.

[0050] With the above solution: By starting the clamping hydraulic rod 44, the synchronous plate 43 can be driven to push downward, so that the fixing convex platform 41 moves downward, realizing the clamping and fixing of the bottom end of the hydraulic cylinder, ensuring the synchronous movement of the bottom ends of each hydraulic cylinder in the multi-stage hydraulic cylinder 3 system, and thus ensuring the stability and balance of the working platform or equipment during the lifting or moving process.

[0051] Referring to Figure 7 Figure, the support frame 5 includes an L-shaped support rod 51 and a C-shaped limit frame 52. There are four groups of L-shaped support rods 51, which are symmetrically distributed on both sides of the lifting platform 6. Two groups of L-shaped support rods 51 on the same side are fixedly connected to a group of C-shaped limit frames 52. The C-shaped limit frame 52 is clamped with the lifting platform 6. The lifting platform 6 includes a platform body 61 and fixed card slots 62. There are multiple groups of fixed card slots 62, which are evenly opened at the bottom end of the platform body 61. The upper fixing block 32 is clamped with the fixed card slots 62.

[0052] With the above solution: The movement range of the lifting platform 6 can be restricted by the C-shaped limit frame 52, ensuring that it works within a safe position, preventing the lifting platform 6 from moving when the multi-stage hydraulic cylinder 3 is installed, causing the lifting platform 6 to shift, resulting in abnormal position changes or instability when the lifting platform 6 is lifted, and thus ensuring the safe operation of the multi-stage hydraulic cylinder 3 and the stability of the lifting platform 6.

[0053] The working principle of the present invention is as follows: During installation, first, arrange multiple sets of multi-stage hydraulic cylinders 3 in a row, place the lower fixing blocks 33 at their bottoms between multiple fixing convex platforms 41, insert the upper fixing blocks 32 at their tops into the fixing slots 62, and start the moving motor 215 to drive the lead screw 212 to rotate, so that the moving block 214 moves along the direction of the slide rail 213 to the side of the multi-stage hydraulic cylinder 3. Then, drive the clamping gear 23 to rotate through the clamping motor 22, so that one end of the clamping rack 25 is inserted into the rack fixing slot 27 at the top of the rack fixing block 26. At this time, the two clamping racks 25 are in contact with multiple sets of multi-stage hydraulic cylinders 3 arranged in a row to clamp the multi-stage hydraulic cylinders 3. After that, through the linear actuator 21 again, move the clamped multiple sets of multi-stage hydraulic cylinders 3 to the bottom of the lifting platform 6. Repeat the operation to place multiple rows of multi-stage hydraulic cylinders 3 between the bottom fixing device 4 of the hydraulic cylinder and the lifting platform 6, and control the spacing of the multi-stage hydraulic cylinders 3 in each row through the position sensor 35 at the bottom of the multi-stage hydraulic cylinder 3 to make the multi-stage hydraulic cylinders 3 evenly distributed. Finally, start the clamping hydraulic rod 44 to push the synchronous plate 43 downward, drive the fixing convex platform 41 to move downward, and reduce the distance between the fixing convex platform 41 and the base 1 to clamp and fix the lower fixing block 33; By starting the clamping hydraulic rod 44, the synchronous plate 43 can be driven to move downward, thereby driving the fixing convex platform 41 to move downward to achieve the clamping and fixing of the bottom end of the hydraulic cylinder, ensuring the synchronous movement of the bottom ends of each hydraulic cylinder in the multi-stage hydraulic cylinder 3 system, and thus ensuring the stability and balance of the working platform or equipment during lifting or moving. Through the upper fixing block 32 and the lower fixing block 33, the installation and adjustment of the hydraulic cylinder are more convenient and fast. The operator can adjust the position of the hydraulic cylinder according to needs to adapt to different working scenarios and requirements, improving the flexibility and applicability of the system. By monitoring and feedback of the position of the hydraulic cylinder body 31 through the position sensor 35, precise control of the position of the hydraulic cylinder can be achieved, ensuring the synchronous movement and positioning accuracy of the multi-stage hydraulic cylinder 3, and improving the working efficiency and accuracy of the system. Through the C-shaped limit frame 52, the movement range of the lifting platform 6 can be restricted to ensure its operation within a safe position, prevent the lifting platform 6 from moving when the multi-stage hydraulic cylinder 3 is installed, causing the lifting platform 6 to shift, resulting in abnormal position changes or instability during the lifting of the lifting platform 6, thereby ensuring the safe operation of the multi-stage hydraulic cylinder 3 and the stability of the lifting platform 6.

[0054] The intelligent control method of the invention includes the following steps:

[0055] S1. First, arrange multiple groups of multi-stage hydraulic cylinders in a row. Place the lower fixing blocks at the bottom ends of the hydraulic cylinders between multiple fixing convex platforms. Insert the upper fixing blocks at the top ends of the hydraulic cylinders into the fixing card slots. Then start the moving motor to drive the screw rod to rotate, causing the moving block to move along the sliding rail direction to the side of the multi-stage hydraulic cylinders. Then drive the clamping gear to rotate through the clamping motor, so that one end of the clamping rack is inserted into the rack fixing slot at the top end of the rack fixing block. At this time, the two clamping racks are in contact with multiple groups of multi-stage hydraulic cylinders arranged in a row to clamp the multi-stage hydraulic cylinders.

[0056] S2. After that, use the linear actuator again to move the multiple groups of multi-stage hydraulic cylinders being clamped to the bottom end of the lifting platform. Repeat the operation to place multiple rows of multi-stage hydraulic cylinders between the bottom fixing device of the hydraulic cylinder and the lifting platform. Control the spacing between the multi-stage hydraulic cylinders in each row through the positioning sensors at the bottom ends of the multi-stage hydraulic cylinders to make the multi-stage hydraulic cylinders evenly distributed.

[0057] S3. Finally, start the clamping hydraulic rod to push the synchronous plate downward, driving the fixing convex platform to move downward, reducing the distance between the fixing convex platform and the base, and clamping and fixing the lower fixing block.

[0058] In S2, when moving multiple groups of multi-stage hydraulic cylinders, an intelligent algorithm combining the fuzzy PID controller and the Deep Deterministic Policy Gradient (DDPG) algorithm is used to optimize the moving process of multiple groups of multi-stage hydraulic cylinders. This algorithm enhances the real-time response ability, optimizes the long-term performance of the control strategy, improves the control accuracy and efficiency, and reduces the system maintenance cost. The specific process is as follows:

[0059] Step 1: Define the state space and action space. The state space includes the position, spacing, speed, and acceleration of the multi-stage hydraulic cylinders. The action space is the force and speed for controlling the movement of the hydraulic cylinders. In the hydraulic cylinder system, the state space reflects the dynamic characteristics and control requirements of the system. In the hydraulic cylinder system, the action space should include the operations that the system can take, that is, the force or speed for controlling the movement of each hydraulic cylinder;

[0060] The state space is used as the input of the DDPG algorithm in the present invention; the input layer of the neural network should include all variables in the state space to learn the state and dynamic characteristics of the system. To better meet the requirements of the intelligent algorithm, the state space contains the following variables:

[0061] The position P of each hydraulic cylinder i : Reflects the position of each hydraulic cylinder relative to the reference point;

[0062] The spacing d between each hydraulic cylinder i : Determines the overall structure and performance of the system;

[0063] The speed v of each hydraulic cylinderi : Represents the movement speed of each hydraulic cylinder, which helps the model to more accurately predict the dynamic behavior of the system;

[0064] The acceleration a of each hydraulic cylinder i : Describes the movement acceleration of each hydraulic cylinder, which can help the algorithm to better control the movement process of the system;

[0065] The state space is represented as:

[0066] S = {P 1 , P 2 ,..., P n , d 1 , d 2 ,..., d n-1 , v 1 , v 2 ,..., v n , a 1 , a 2 ,..., a n}

[0067] Among them, n represents the number of hydraulic cylinders;

[0068] The action space is the output of the DDPG algorithm in the present invention; the output layer of the neural network should generate the moving force or speed of each hydraulic cylinder to achieve the control of the system; in order to better meet the requirements of the intelligent algorithm, the action space includes the following variables:

[0069] The moving force F for controlling each hydraulic cylinder i : Represents the force applied to each hydraulic cylinder to push them to move;

[0070] The moving speed v for controlling each hydraulic cylinder i : Represents the moving speed of each hydraulic cylinder, which can directly control the movement process of the hydraulic cylinder;

[0071] The action space can be represented as:

[0072] A = {F 1 , F 2 ,..., F n , v 1 , v 2 ,..., v n}

[0073] Step 2: Design a fuzzy PID controller to generate a control signal according to the state and error of the multi-stage hydraulic cylinder system; the output of the fuzzy PID controller can be adjusted according to the state and error of the multi-stage hydraulic cylinder system to achieve precise control of the hydraulic cylinder. The following are the specific steps for designing the fuzzy PID controller:

[0074] 1. Select the triangular membership function to fuzzify the error and the rate of change of error of the multi-stage synchronous hydraulic cylinder system into membership values in the fuzzy set, laying the foundation for subsequent fuzzy inference and control signal generation. This method can effectively handle the nonlinear and uncertain problems of the hydraulic system, improving the control accuracy and response speed of the system.

[0075] Membership function NB of error e : The membership function of error is used to map the error e of the multi-stage synchronous hydraulic cylinder system into the fuzzy set, including memberships such as "negative large", "negative medium", "zero", "positive medium", "positive large", etc.; enabling the system to have different processing methods for different error situations. The specific mathematical expression:

[0076]

[0077] where x represents the value of the error, c e : The central position of the triangle, representing the error value at the center of the fuzzy set, a e : The width parameter of the triangle, representing the tolerance of the error, which determines the width of the fuzzy set on the error axis;

[0078] Membership function NB of the rate of change of error Δe : The membership function of the rate of change of error is used to map the rate of change of error Δe of the multi-stage synchronous hydraulic cylinder system into the fuzzy set, also divided into memberships such as "negative large", "negative medium", "zero", "positive medium", "positive large", etc., so that the system can adjust the control strategy according to the rate of change of error. The specific mathematical expression:

[0079]

[0080] where x represents the value of the rate of change of error, c Δe : The central position of the triangle, representing the value of the rate of change of error at the center of the fuzzy set, a Δe : The width parameter of the triangle, representing the tolerance of the rate of change of error; it determines the width of the fuzzy set on the rate of change of error axis;

[0081] 2. In the control process of the multi-stage synchronous hydraulic cylinder, the fuzzification output stage is crucial; according to the membership functions NB e and NB Δe of the error e and the rate of change of error Δe, use the fuzzy rule base for fuzzy inference to obtain the membership function PB u of the control output; furthermore, the fuzzification output method can be effectively applied in the multi-stage synchronous hydraulic cylinder system, which can optimize the control accuracy and response speed while dealing with the complex system dynamics and uncertainties, improving the performance of the overall system;

[0082] Fuzzy inference: Using the fuzzy rule base, perform fuzzy inference based on the membership values of the error e and the error change rate Δe;

[0083] Through the rules defined in the fuzzy rule base,

[0084] If e is "positive large" and Δe is "positive large", then u is "negative large";

[0085] If e is "positive medium" and Δe is "zero", then u is "positive medium";

[0086] If e is "negative large" and Δe is "negative medium", then u is "positive large";

[0087] Derive the membership function of the control output u according to these rules;

[0088] Fuzzyfication of the control output: Fuzzyfy the control output u, and use the triangular method to map u into the corresponding membership function. The membership function of the control output includes "negative large", "negative medium", "zero", "positive medium", "positive large", etc. The specific expressions of the membership functions are as follows:

[0089]

[0090] Among them, x represents the value of the control output, c u is the central position of the triangle, representing the control output value at the center of the fuzzy set, a u is the width parameter of the triangle, representing the tolerance of the control output; it determines the width of the fuzzy set on the control output axis. The vertex position of the triangle is determined by c u ±a u determined;

[0091] Actual action adjustment: According to the magnitude of the control output u, the system adjusts the actual action to achieve precise control of the multi-stage synchronous hydraulic cylinder. Through the combination of fuzzy inference and membership functions, the control system can handle the nonlinearity and uncertainty of the hydraulic cylinder, ensuring that the synchronous movement of the synchronous hydraulic cylinder reaches the expected performance;

[0092] 3. In the control system of the multi-stage synchronous hydraulic cylinder, the fuzzy rule base consists of a series of fuzzy rules. Each rule specifies the control output action to be taken under specific error and error change rate conditions; the design of the fuzzy rule base is usually based on expert experience or determined through a trial-and-error method, combining the actual working conditions and control requirements of the multi-stage synchronous hydraulic cylinder system; the following is a detailed description of the design process:

[0093] Representation of the fuzzy rule base: The fuzzy rule base is usually represented by a series of rules in the form of "IF-THEN"; each rule contains a condition part and a conclusion part;

[0094] IF (Condition part) THEN (Conclusion part)

[0095] The condition part describes the current state of the system, usually including fuzzy sets of the error e and the rate of change of error Δe, and the conclusion part specifies the corresponding control output action;

[0096] In the present invention, triangular fuzzy sets are selected to determine the error and the rate of change of error, and five control output actions are set: "negative large", "negative medium", "zero", "positive medium", "positive large", and triangular fuzzy sets are used to represent these actions; the membership functions of the five set control output actions are as follows:

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] Based on expert experience or trial-and-error rules, a fuzzy rule base is designed; the following rules are obtained:

[0103] IF the error (e) is "positive large" AND the rate of change of error (Δe) is "positive large" THEN the control signal (u) is "negative large"

[0104] When the error is very large and increasing positively, and the error is changing positively (i.e., the error is increasing), the control signal takes a value of negative large. This means that the system needs to rapidly reduce the error, and the trend of positive increase in the error needs to be suppressed;

[0105] IF the error (e) is "positive medium" AND the rate of change of error (Δe) is "zero" THEN the control signal (u) is "positive medium"

[0106] When the error is at a medium level and the rate of change of error is zero, the control signal takes a value of positive medium; this indicates that the system has approached the desired state and the error trend is stable, so the control signal remains at a medium level to maintain the current state;

[0107] IF the error (e) is "negative large" AND the rate of change of error (Δe) is "negative medium" THEN the control signal (u) is "positive large"

[0108] When the error is negative large and the rate of change of error is increasing negatively, the control signal takes a value of positive large; this shows that the system needs to rapidly increase the control to reduce the negative large error, and the trend of negative increase needs to be suppressed;

[0109] IF the error (e) is "zero" AND the error change rate (Δe) is "positive large", THEN the control signal (u) is "negative medium"

[0110] When the error is zero and the error change rate is increasing in the positive direction, the control signal takes a value of negative medium; this indicates that the system is currently in the desired state, but the error is increasing in the positive direction, so a negative control is needed to prevent the error from increasing further;

[0111] IF the error (e) is "negative medium" AND the error change rate (Δe) is "negative large", THEN the control signal (u) is "negative large"

[0112] When the error is negative medium and the error change rate is increasing in the negative direction, the control signal takes a value of negative large; this shows that the system needs to continue to reduce the error, but since the error change rate is increasing in the negative direction, a larger negative control is needed to cope with the change in the error;

[0113] Based on the current error e and error change rate Δe, fuzzy inference is carried out according to the fuzzy rule base to obtain the fuzzy set of the control output u; finally, the fuzzy output is defuzzified to obtain the specific control output value;

[0114] 4. In a multi-stage synchronous hydraulic cylinder, in order to achieve precise control of the system, the weighted average method is used to calculate the output of the fuzzy PID controller; the values in the membership function of each output and the preset weights are used to calculate the final output to ensure that the multi-stage synchronous hydraulic controller can effectively adjust the system movement under different working conditions;

[0115] The weighted average method is used to calculate the output of the fuzzy PID controller; the membership value of each control output is multiplied by the corresponding weight, and all the weighted values are summed to obtain the final output of the fuzzy PID controller; by comprehensively considering the contribution degree of each output, precise control of the multi-stage synchronous hydraulic cylinder can be achieved, improving the stability and performance of the system.

[0116] 5. In a multi-stage synchronous hydraulic cylinder, according to the fuzzy output obtained in the fuzzy inference stage, the membership value of each output value and the corresponding control output value are determined; in order to achieve precise control, a weight is set for each output value, and these weights represent the contribution degree of the output value to the final result;

[0117] According to the fuzzy output obtained in the fuzzy inference stage, the membership value of each output value is determined, and a weight is set for each output value; these weights can be set according to the actual situation, usually determined by the system designer according to experience or the characteristics of the specific problem; in the control of the multi-stage synchronous hydraulic cylinder, the setting of the weights is crucial for the stability and performance of the system.

[0118] Multiply each output value by its corresponding membership degree value and weight, and then sum all the weighted values to obtain the final control output value; by comprehensively considering the membership degree and weight of each output value, we can determine the optimal control strategy to achieve precise control and stable operation of the multi-stage synchronous hydraulic cylinder system;

[0119] Step 3: In the application of the multi-stage synchronous hydraulic cylinder, use the Deep Deterministic Policy Gradient (DDPG) algorithm to train a neural network to learn the optimal policy of the system; the DDPG algorithm can select the optimal action according to the current state, so as to maximize the long-term reward;

[0120] 1. In the application of the multi-stage synchronous hydraulic cylinder, we designed two neural networks, namely the Actor network and the Critic network;

[0121] Actor network

[0122] Structure: Multi-Layer Perceptron (MLP)

[0123] Hidden layer: 2 - 3 layers, each layer contains 128 to 256 neurons

[0124] Activation function:

[0125] Hidden layer: Use the ReLU activation function; the mathematical expression of ReLU is f(x) = max(0, x),

[0126] where:

[0127] x is the input parameter of the function and can be a real number;

[0128] ReLU(x) represents the output value of the ReLU function corresponding to the input x;

[0129] max(0, x) represents taking the larger value between 0 and x as the output;

[0130] The role of the ReLU function is to map the input signal to a non-negative value. When the input x is greater than zero, the output remains unchanged as x. When the input is less than or equal to zero, the output is zero; the main advantage of the ReLU function is simple and effective, and it has sparse activation in deep neural networks, which helps to alleviate the vanishing gradient problem;

[0131] Output layer: Use the tanh activation function because the control signal is usually in the range of [-1, 1]; the expression of the tanh function is

[0132] where:

[0133] x is the input parameter of the function and can be a real number;

[0134] e is the base of the natural logarithm, approximately equal to 2.71828;

[0135] tanh(x) represents the output value of the hyperbolic tangent function corresponding to the input x; the role of the hyperbolic tangent function is to map real numbers to the interval [-1, 1]. Its curve shape is an S-shaped curve, and it approaches 1 and -1 when the input approaches positive infinity and negative infinity, respectively, and approaches 0 when approaching 0;

[0136] Input: System state space s

[0137] Output: Control signal a of each hydraulic cylinder. The output vector a = [u 1 , u 2 ,..., u n , and each u i corresponds to the control signal of one cylinder and ranges between [-1, 1];

[0138] Critic network

[0139] Structure: Multilayer perceptron (MLP)

[0140] Hidden layer: 2 - 3 layers, each layer contains 128 to 256 neurons

[0141] Activation function: Use the ReLU activation function; the mathematical expression of ReLU is f(x) = max(0, x),

[0142] where:

[0143] x is the input parameter of the function and can be a real number;

[0144] ReLU(x) represents the output value of the ReLU function corresponding to the input x;

[0145] max(0, x) means taking the larger value between 0 and x as the output;

[0146] The role of the ReLU function is to map the input signal to non - negative values. When the input x is greater than zero, the output remains unchanged as x. When the input is less than or equal to zero, the output is zero. The main advantages of the ReLU function are simple and effective, and it has sparse activation in deep neural networks, which helps to alleviate the vanishing gradient problem;

[0147] Input: System state s and action a

[0148] Output: Action value function Q(s, a|θ Q ), which is used to evaluate the value of the given state and action Q(s, a|θ Q ) = f 3 (W 3 *f 2 (W 2 *f1 (W 1 *[s, a] + b 1 ) + b 2 ) + b 3 )

[0149] Where:

[0150] s is the system state vector;

[0151] a is the action vector;

[0152] [s, a] represents concatenating the state s and the action a into an input vector;

[0153] W1, W2, W3 are the weight matrices of each layer of the network;

[0154] b1, b2, b3 are the bias vectors of each layer of the network;

[0155] F1, f2, f3 are the activation functions of each layer. Usually, the ReLU activation function is used for the hidden layer, and the linear activation function is used for the output layer;

[0156] 2. In a multi - stage synchronous hydraulic cylinder system, we need to set the following parameters:

[0157] Training steps T: The training steps refer to the total number of update steps during the training process; for a multi - stage synchronous hydraulic cylinder system, this means the number of times the neural network parameters are updated, which determines the total number of times the algorithm samples and updates the neural network parameters in the experience replay buffer; The training steps are set to 100,000 steps to ensure that the algorithm has enough time to learn and optimize the control strategy, thereby improving the final control performance.

[0158] Batch size B: The batch size is the number of samples sampled from the experience replay buffer each time, which determines the number of samples used when updating the network parameters each time; in a multi - stage synchronous hydraulic cylinder system, a larger batch size can provide a more stable gradient estimate, but it will increase the computational cost; while a smaller batch size can speed up the calculation, but may lead to unstable gradient estimates; We choose 64 as the batch size to balance computational efficiency and stability;

[0159] Experience replay buffer size N: The experience replay buffer size refers to the maximum number of samples that can be stored in the experience replay buffer; in a multi - stage synchronous hydraulic cylinder system, a larger buffer can contain more diverse samples, thereby improving the generalization ability and learning effect of the algorithm; We set the experience replay buffer size to 1,000,000 to ensure sufficient storage of the experience samples collected during the training process;

[0160] Soft update parameter τ: The soft update parameter is the update rate of the target network parameters, which controls the update speed of the target network parameters; in the multi-stage synchronous hydraulic cylinder system, the role of the soft update parameter is to make the parameters of the target network smoothly approach the parameters of the current network to maintain the relative stability of the network parameters; we set the soft update parameter τ = 0.001 to ensure the smooth update of the target network parameters and avoid drastic fluctuations;

[0161] Discount factor γ: The discount factor is used to balance the importance of the current reward and the future reward, and determines the degree of emphasis on the future reward when the algorithm calculates the cumulative reward; in the multi-stage synchronous hydraulic cylinder system, we set the discount factor γ = 0.99 to balance between short-term and long-term rewards;

[0162] 3. Randomly initialize the Actor network parameters θ μ and the Critic network parameters θ Q , initialize the experience replay buffer, create an experience replay buffer with a size of N to store the experience samples during the training process; start training, randomly sample a batch of samples with a size of B from the experience replay buffer; including the current state s t 、the action a taken t 、the reward r t and the next state s t+1 , store the sample (s t , a t , r t , s t+1 ) into the experience replay buffer; calculate the target Q value y i for updating the Critic network; estimate the long-term cumulative reward obtained by taking the action μ′(s i |θ i+1 ′) in the current state s μ ′,

[0163] where Q′(s i+1 , μ′(s i+1 |θ μ ′)|θ Q ′) estimates the cumulative reward obtained by taking the action μ′(s i+1 |θ i+1 ′) in the next state s μ ′; the specific expression:

[0164] y i = r i + γQ′(s i+1 , μ′(s i+1 , θ μ ′)|θ Q ′)

[0165] where:

[0166] y i : The target Q-value at time step i;

[0167] r i : The reward at time step i;

[0168] γ: Discount factor, used to balance the importance of current and future rewards;

[0169] Q′: The action-value function of the target Critic network;

[0170] s i+1 : The next system state at time step i+1;

[0171] μ′: The action selection strategy of the target Actor network;

[0172] θ μ ′: The parameters of the target Actor network;

[0173] θ Q ′: The parameters of the target Critic network;

[0174] Update the Critic network by minimizing the loss function to adjust the parameters of the Critic network to approximate the true action-value function; The goal of this loss function is to minimize the mean squared error between the predicted value Q(s i , a i |θ Q ) and the target value y i so that the prediction of the Critic network is close to the true action-value function;

[0175]

[0176] Where:

[0177] L: Loss function, representing the difference between the model's predicted value and the actual value;

[0178] B: Batch size for each training sample;

[0179] i: Sample index in the batch;

[0180] y i : The target Q-value at time step i, usually the sum of the current reward and the estimated action-value function of the next state, i.e., y i =r i +γQ′(s i+1 , μ′(s i+1 , θ μ ′)|θ Q ′)

[0181] Q(si , a i |θ Q ): The predicted value of the action-value function of the Critic network for a given state and action;

[0182] θ Q : The parameters of the Critic network;

[0183] Update the Actor network. By maximizing the action-value function, adjust the parameters of the Actor network to improve the effect of the current policy. The optimization objective of this objective function is to maximize the expected value of the action-value function corresponding to the action generated by the Actor network, so that the action generated by the current policy can maximize the action-value function, thereby improving the overall control performance;

[0184] The specific expression is as follows:

[0185]

[0186] Where:

[0187] J(θ μ ): The objective function of the Actor network, representing the expected value of the action-value function corresponding to the action generated by the Actor network;

[0188] B: The batch size of each training sample;

[0189] i: The sample index in the batch;

[0190] Q(s, μ(s|θ μ )|θ Q ): The action-value function estimated by the Critic network according to the current state s and the action μ(s|θ μ ) generated by the Actor network;

[0191] θ μ : The parameters of the Actor network;

[0192] Soft update the target network: Update the parameters θ Q′ and θ μ′ , making the parameters of the target network gradually approach the parameters of the current network to maintain the stability and learning effect of the target network; The role of this formula is to update the parameters of the target network by weighted average according to the parameters θ of the current network and the parameters θ′ of the target network, so as to keep the parameter changes of the target network relatively smooth, avoid drastic parameter fluctuations, and thus improve the stability and learning effect of the overall training; The specific expression is as follows:

[0193] θ Q ′←τ′θ Q +(1 - τ)θ Q′

[0194] θ μ ′ ← τ′θ μ +(1 - τ)θ μ ′

[0195] Repeat the above process until the training step number T is reached;

[0196] 4. In a multi - stage synchronous hydraulic cylinder system, the input variable error e and the error change rate Δe are fuzzified into fuzzy sets to improve the robustness of the control system; for the position error e, the fuzzy set is defined as {Negative Big (NB), Negative Medium (NM), Negative Small (NS), Zero (ZO), Positive Small (PS), Positive Medium (PM), Positive Big (PB)}, and a fuzzy rule base is established according to experience and system knowledge;

[0197] For the control output u, different membership values are set, {NB: 0.2, NM: 0.5, NS: 0.3}, and weights are set for each fuzzy output value. Then each output value is multiplied by its corresponding membership value and weight, and then all the weighted values are summed to obtain the final control output value; the specific formula is as follows:

[0198] G u final = ∑(μ i * u i * w i )

[0199] Where μ i is the membership value, μ i is the fuzzy output value, and w i is the corresponding weight;

[0200] 5. To ensure the stability and performance of the multi - stage synchronous hydraulic cylinder system, it is crucial to verify the performance of the controller in a simulation environment; through the tests in the simulation environment, the performance of the controller under various working conditions can be verified, and parameter adjustment and control strategy optimization can be carried out to ensure the good operation of the controller in the actual system;

[0201] During the verification process, it is necessary to ensure that the sensors and actuators in the actual system can accurately acquire and execute the control signals; if necessary, calibration and debugging can be carried out to ensure the stability and accuracy of the system;

[0202] Once the controller is verified through in the simulation environment, it can be deployed to the actual multi - stage synchronous hydraulic cylinder system for real - time control; by real - time monitoring the state and control signals of the system, it can be ensured that the synchronous movement of the hydraulic cylinders reaches the set performance indicators; according to the actual operation situation, on - line adjustment of the controller can be carried out, including adjusting the fuzzy rules and weights, or adjusting the parameters of the DDPG algorithm to further optimize the system performance;

[0203] This verification and optimization process is continuous and is constantly adjusted and improved during actual operation to ensure that the system always maintains the best state and meets the changing requirements and working environments;

[0204] Parameter Variable Explanation

[0205] s t : The system state at time step t;

[0206] a t : The action taken at time step t;

[0207] r t : The reward at time step t;

[0208] s t+1 : The next system state at time step t+1;

[0209] θ μ : The parameters of the Actor network;

[0210] θ Q : The parameters of the Critic network;

[0211] θ Q ′: The parameters of the target Critic network;

[0212] θ μ ′: The parameters of the target Actor network;

[0213] γ: The discount factor, used to balance the importance of current and future rewards;

[0214] τ: The soft update parameter, controlling the smooth update degree of the target network;

[0215] T: The total number of training steps;

[0216] B: The batch size of each training sample;

[0217] N: The size of the experience replay buffer;

[0218] Step 4: To achieve the best control effect, in the multi-level synchronous hydraulic cylinder system, the fuzzy PID controller and the DDPG algorithm are combined to make full use of their respective advantages; in this fusion method, the output of the fuzzy PID controller will be used as the action input of the DDPG algorithm, and the control strategies of both will complement and optimize each other;

[0219] The fuzzy PID controller generates a control signal based on the current system state and error; this signal u is fuzzy, representing the possibilities of different control actions and having a certain membership function description; while the DDPG algorithm requires a continuous action space as input to search for the optimal control strategy in the action space; therefore, the output u of the fuzzy PID controller is used as the action input a of the DDPG algorithm, converting the fuzzy control signal into an action in the continuous action space;

[0220] The control strategy combining the fuzzy PID controller and the DDPG algorithm has the following advantages: The fuzzy PID controller has strong robustness and real-time performance, can quickly respond to changes in the system state, and generate corresponding control signals; it is applicable to control under various working conditions and can handle the nonlinearity and uncertainty of the system; while the DDPG algorithm has powerful optimization capabilities and can find the optimal control strategy of the system through continuous learning and optimization to maximize the long-term reward. The DDPG algorithm uses a deep neural network to model the complex system dynamics and conducts efficient searches in the continuous action space;

[0221] To achieve the best control effect, the influence of the fuzzy PID controller and the DDPG algorithm can be balanced by adjusting the weights; specifically, the outputs of the two can be weighted and added through a linear combination, as shown below:

[0222] G final = α * uPID + (1 - α) * uDDPG

[0223] G final : The final control signal, the result obtained through the weighting method;

[0224] uPID: The control signal generated by the fuzzy PID controller;

[0225] uDDPG: The control signal generated by the DDPG algorithm;

[0226] α: The weighting coefficient, with a value range of [0, 1], used to balance the influence of the fuzzy PID controller and the DDPG algorithm; when α = 0, the control signal of the DDPG algorithm is completely adopted; when α = 1, the control signal of the fuzzy PID controller is completely adopted;

[0227] Step Five: In the multi-stage synchronous hydraulic cylinder system, we adjust and optimize the parameters of the fuzzy PID controller and the DDPG algorithm by real-time monitoring the system state and performance indicators and based on the feedback information to maintain the stability and performance of the system; Real-time monitoring of the system state and performance indicators Real-time monitoring of the key state and performance indicators of the system;

[0228] The status and performance indicators of the real-time monitoring system use devices such as pressure sensors and position sensors to monitor key parameters of the hydraulic cylinder in real time, including the error e, the error change rate Δe, the system pressure, and the flow rate, and input the monitoring data into the control system in real time;

[0229] Fuzzy PID controller parameter adjustment; Set initial parameters: Set the initial parameters of the fuzzy PID controller, Kp = 1.0, Ki = 0.1, Kd = 0.01;

[0230] Proportional gain Kp: The degree of response of the control signal to the error;

[0231] Integral gain Ki: The degree of response of the control signal to the cumulative error;

[0232] Derivative gain Kd: The degree of response of the control signal to the error change rate;

[0233] According to the system error and the error change rate, adjust the proportional gain Kp, the integral gain Ki, the derivative gain Kd, and the fuzzy rule base to enhance the response speed and stability of the system to the error;

[0234] DDPG algorithm parameter adjustment

[0235] Set the initial parameters of the DDPG algorithm, learning rate α = 0.001, discount factor γ = 0.99, and the neural network structure has 3 layers with 64 neurons in each layer;

[0236] According to the response speed and oscillation conditions of the system under certain working conditions, adjust the learning rate, the discount factor, the exploration strategy, and the neural network structure to optimize the control strategy;

[0237] Combine the outputs of the fuzzy PID controller and the DDPG algorithm by weighting to obtain the final control signal, and balance the influence of the two by adjusting the weight α;

[0238] According to the system state and control signal data obtained in real time, adjust the parameters of the fuzzy PID controller and the DDPG algorithm;

[0239] Evaluate the response performance, error, response time, and oscillation situation indicators of the system in real time;

[0240] Continuously repeat the above steps to continuously optimize the system performance and ensure stability and control effect under different working conditions.

[0241] The above-mentioned is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A multi-stage synchronous hydraulic cylinder, characterized in that: include: A base (1), wherein the top of the base (1) is fixedly connected to a hydraulic cylinder bottom fixing device (4), a clamping device (2) is arranged at the side end of the hydraulic cylinder bottom fixing device (4), the clamping device (2) is fixedly connected to the base (1), a support frame (5) is arranged at the side end of the clamping device (2), the support frame (5) is fixedly connected to the top of the base (1), a lifting platform (6) is clamped at the top of the support frame (5), a multi-stage hydraulic cylinder (3) is arranged between the lifting platform (6) and the hydraulic cylinder bottom fixing device (4), the bottom end of the multi-stage hydraulic cylinder (3) is clamped to the hydraulic cylinder bottom fixing device (4), and the top end of the multi-stage hydraulic cylinder (3) is clamped to the lifting platform (6); The clamping device (2) comprises a linear drive (21), a clamping motor (22), a clamping gear (23), an L-shaped fixing block (24), a clamping rack (25), a rack fixing block (26) and a rack fixing groove (27); The multi-stage hydraulic cylinder (3) comprises a hydraulic cylinder body (31), an upper fixed block (32), a lower fixed block (33), a mounting groove (34) and a positioning sensor (35); The hydraulic cylinder bottom end fixing device (4) comprises a fixing convex platform (41), a connecting rod (42), a synchronous plate (43) and a clamping hydraulic rod (44); The support frame (5) comprises an L-shaped support rod (51) and a C-shaped limiting frame (52); The linear drive (21) comprises a fixed frame (211), a screw rod (212), a slide rail (213), a moving block (214) and a moving motor (215); The clamping motor (22) is fixedly connected to a group of moving blocks (214); the output end of the clamping motor (22) is fixedly connected to the clamping gear (23); the side end of the clamping gear (23) is meshedly connected to the clamping rack (25); the clamping rack (25) is arranged at the inner end of the L-shaped fixed block (24); the L-shaped fixed block (24) is fixedly connected to the clamping motor (22); the rack fixing block (26) is fixedly connected to another group of moving blocks (214); the rack fixing groove (27) is opened at the top of the rack fixing block (26); the clamping rack (25) is plugged into the rack fixing groove (27); the clamping device (2) is provided with two groups, which are rotationally symmetrically distributed at the top of the two groups of moving blocks (214); the spacing between the two groups of clamping racks (25) is the same as the diameter of the multi-stage hydraulic cylinder (3); The movable top end of the hydraulic cylinder body (31) is fixedly connected to the upper fixed block (32), the bottom end of the hydraulic cylinder body (31) is fixedly connected to the lower fixed block (33), the mounting groove (34) is opened at the bottom end of the lower fixed block (33), the positioning sensor (35) is arranged at the inner end of the mounting groove (34) and is fixedly connected to the lower fixed block (33), and the hydraulic cylinder body (31) is provided with multiple groups; The fixed convex platform (41) is provided with multiple groups, and each two groups are symmetrically distributed on both sides of a row of multi-stage hydraulic cylinders (3). The lower fixed block (33) of each group is clamped with two groups of fixed convex platforms (41). The connecting rod (42) is provided with multiple groups. The connecting rod (42) passes through the base (1). The top end of the connecting rod (42) is fixedly connected to the fixed convex platform (41), and the bottom end is fixedly connected to the synchronous plate (43). The clamping hydraulic rod (44) is provided with four groups, which are symmetrically distributed on the top end of the synchronous plate (43). The fixed end of the clamping hydraulic rod (44) is fixedly connected to the bottom end of the base (1), and the movable end of the clamping hydraulic rod (44) is fixedly connected to the top end of the synchronous plate (43). Four groups of L-shaped support rods (51) are provided and symmetrically distributed on both sides of the lifting platform (6); two groups of L-shaped support rods (51) on the same side are fixedly connected to a group of C-shaped limit frames (52); and the C-shaped limit frames (52) are clamped with the lifting platform (6); The fixed frame (211) is fixedly connected to the base (1); the screw rod (212) is arranged at the inner end of the fixed frame (211), passes through the fixed frame (211), and is rotatably connected to the fixed frame (211); two groups of slide rails (213) are arranged, symmetrically distributed on both sides of the screw rod (212), and are fixedly connected to the fixed frame (211); the moving block (214) is threadedly connected to the screw rod (212) and is slidably connected to the slide rail (213); the moving motor (215) is fixedly connected to the side end of the fixed frame (211); the output end of the moving motor (215) is fixedly connected to the screw rod (212); and the linear drive (21) is arranged in two groups, symmetrically distributed on the top of the base (1); The lifting platform (6) comprises a platform body (61) and a fixed slot (62).

2. A multi-stage synchronous hydraulic cylinder according to claim 1, characterized in that: The fixed card slots (62) are provided in multiple groups and are evenly opened at the bottom end of the platform (61), and the upper fixed card block (32) is engaged with the fixed card slots (62).

3. The intelligent control method of a multi-stage synchronous hydraulic cylinder according to claim 2 is characterized in that: The following steps are involved: S1. First, multiple groups of multi-stage hydraulic cylinders (3) are arranged in a row, and the lower fixed blocks (33) at the bottom are placed between multiple groups of fixed convex platforms (41), and the upper fixed blocks (32) at the top are inserted into the fixed slots (62), and the moving motor (215) is started to drive the screw rod (212) to rotate, so that the moving block (214) moves to the side end of the multi-stage hydraulic cylinder (3) along the direction of the slide rail (213), and then the clamping motor (22) drives the clamping gear (23) to rotate, so that one end of the clamping rack (25) is inserted into the rack fixing slot (27) at the top of the rack fixing block (26). At this time, the two groups of clamping racks (25) are in contact with the multiple groups of multi-stage hydraulic cylinders (3) arranged in a row, and the multi-stage hydraulic cylinders (3) are clamped; S2. After that, the clamped multiple groups of multi-stage hydraulic cylinders (3) are moved to the bottom of the lifting platform (6) again by the linear drive (21), and the operation is repeated to place multiple rows of multi-stage hydraulic cylinders (3) between the hydraulic cylinder bottom end fixing device (4) and the lifting platform (6), and the spacing of the multi-stage hydraulic cylinders (3) in each row is controlled by the positioning sensor (35) at the bottom of the multi-stage hydraulic cylinders (3) so that the multi-stage hydraulic cylinders (3) are evenly distributed; S3. Finally, the clamping hydraulic rod (44) is started to push the synchronous plate (43) downward, driving the fixed convex platform (41) to move downward, so that the distance between the fixed convex platform (41) and the base is reduced, and the lower fixed block (33) is clamped and fixed.

4. The method according to claim 3, characterized in that In S2, when multiple groups of multi-stage hydraulic cylinders are moved, the intelligent algorithm of the fuzzy PID controller combined with the deep deterministic policy gradient DDPG algorithm is used to optimize the movement process of multiple groups of multi-stage hydraulic cylinders.

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