An energy-saving vibration isolation platform and its parameter compensation vibration isolation control method and control system

Abstract

The present disclosure provides an energy-saving vibration isolation platform, comprising an upper platform, a lower platform, a control assembly, a sensor assembly, at least four execution cylinders, and at least two moving pairs; wherein the execution cylinder is a gas balance electric cylinder; the gas balance electric cylinder comprises a tightly connected electric cylinder and a pneumatic cylinder, the electric cylinder and the pneumatic cylinder are parallel in shaft, and the inner piston rod ends of the two are fixed on the same connecting block; the connecting block is connected with a first hooke joint, and the end of the gas balance electric cylinder not connected with the connecting block is connected with a second hooke joint; the electric cylinder serves as a controlled execution mechanism, and the pneumatic cylinder is filled with gas of a certain pressure to generate a support force along the axial direction of the electric cylinder to balance the gravity of the load of the energy-saving vibration isolation platform. The present disclosure also provides a control method and system of the energy-saving vibration isolation platform. The use of the present application can improve the vibration isolation effect of the energy-saving vibration isolation platform.

Description

Technical Field

[0001] This invention belongs to the field of vibration isolation control, and particularly relates to an energy-saving vibration isolation platform and its parameter compensation vibration isolation control method and control system. Background Technology

[0002] The rapid development of science and technology has promoted in-depth research on various aspects of vibration isolation platforms. Vibration isolation platforms can generally be divided into two types based on their structure: series and parallel. Series platforms have a simple structure and low energy consumption, but suffer from poor load capacity and moderate structural stability. In contrast, parallel platforms have greater load-bearing capacity and structural stiffness, while also exhibiting strong robustness, making them suitable for various working environments. The driving methods for vibration isolation platforms generally include electric drive and hydraulic drive. Hydraulic drive offers higher power density but is more difficult to maintain; electric drive provides better response performance, higher control precision, and is easier to maintain.

[0003] Vibration isolation platforms reduce or eliminate vibrations from the external environment through active or passive mechanisms, maintaining the stability of equipment or personnel on the platform and thus improving the safety and reliability of platform operations. Vibration isolation platforms have wide applications in various fields, such as vehicle and ship transport of precision equipment, safe transport of seriously ill or injured personnel in complex environments, vibration isolation of marine vessel operating platforms, and reconnaissance by military shipborne radar.

[0004] Electric vibration isolation platforms offer advantages such as fast response, high control precision, and strong anti-interference capabilities under high load conditions, but they suffer from high energy consumption. Air-balanced electric cylinder vibration isolation platforms, by combining two servo drive methods, achieve both high control precision and dynamic response performance while maintaining energy efficiency. The platform vibration isolation control method first constructs a platform dynamic model, then uses sensor data to calculate the forces on each drive chain, thereby obtaining the target displacement of each drive chain and moving it to the target position to achieve vibration isolation. During the platform's movement, the movement of the energy-saving mechanism causes output changes, which are considered external disturbances and affect the control precision of the actuator and the platform's vibration isolation effect to some extent. To achieve better vibration isolation control for the energy-saving platform, a parameter-compensated vibration isolation control scheme needs to be designed based on the platform's structure and the characteristics of the energy-saving mechanism. Summary of the Invention

[0005] In view of this, the present invention provides an energy-saving vibration isolation platform and a parameter compensation vibration isolation control method and control system for the energy-saving vibration isolation platform, which can improve the vibration isolation effect of the energy-saving vibration isolation platform.

[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0007] An energy-saving vibration isolation platform includes: an upper platform, a lower platform, a control assembly, a sensor assembly, at least four actuators, and at least two sliding pairs.

[0008] The actuator is a pneumatically balanced electric cylinder. The pneumatically balanced electric cylinder includes an electric cylinder and a pneumatic cylinder connected in parallel. The axes of the electric cylinder and the pneumatic cylinder are parallel, and the ends of their inner piston rods are fixed on the same connecting block. The connecting block is connected to a first Hooke hinge, and the end of the pneumatically balanced electric cylinder not connected to the connecting block is connected to a second Hooke hinge. The electric cylinder acts as the controlled actuator, and the pneumatic cylinder is filled with gas at a certain pressure to generate a supporting force along the axial direction of the electric cylinder to balance the weight of the energy-saving vibration isolation platform load.

[0009] The air-balanced electric cylinders are symmetrically distributed and supported between the upper and lower platforms; the movable pair is also supported between the upper and lower platforms.

[0010] The sensor assembly includes upper and lower platform attitude sensors and a pneumatic balance electric cylinder force sensor.

[0011] The control component estimates the variable stiffness parameter K(k) of the pneumatic cylinder caused by its motion state. g Using this variable stiffness parameter K(k) g Vibration isolation parameters are compensated for for the electric cylinder to obtain the compensated electric cylinder control quantity, which drives the electric cylinder to perform linear extension and retraction.

[0012] Preferably, the pneumatic balance electric cylinder includes one electric cylinder and two pneumatic cylinders; the pneumatic levers are symmetrically distributed on both sides of the electric cylinder and are in close contact with the cylinder body of the electric cylinder, and the inner piston rods of the electric cylinder and the two pneumatic cylinders are parallel to each other.

[0013] Preferably, the energy-saving vibration isolation platform includes four air-balanced electric cylinders, one central sliding joint, and two side sliding joints. The four air-balanced electric cylinders A, B, C, and D are distributed clockwise or counterclockwise at the four corners of the platform. A side sliding joint is set between air-balanced electric cylinders A and B, and a side sliding joint is set between air-balanced electric cylinders C and D. A central sliding joint is set at the center of the platform. The two ends of the air-balanced electric cylinders are connected to the upper platform and the lower platform respectively through Hooke's joints. The upper end of the central sliding joint is fixed to the upper platform, and the lower end is connected to the lower platform through a Hooke's joint. The upper end of the side sliding joints is connected to the upper platform through a single-degree-of-freedom hinge, and the lower end is connected to the lower platform through a Hooke's joint.

[0014] Preferably, the force sensor of the air-balanced electric cylinder is a strain-type digital force sensor, which is installed at the bottom of the air-balanced electric cylinder.

[0015] The present invention also provides a control method for an energy-saving vibration isolation platform, the method comprising the following steps:

[0016] Step 1: Control the extension and retraction of the electric cylinder in the air-balanced electric cylinder to drive the upper platform of the energy-saving vibration isolation platform to move. At the same time, the pneumatic cylinder in the air-balanced electric cylinder also passively extends and retracts synchronously; collect the actual force F of the electric cylinder. l Solve for the six-dimensional stress τ on the vibration isolation platform;

[0017] Step 2: Based on the actual motion state of the pneumatic cylinder, estimate the variable stiffness parameter K(k) generated by the motion of the pneumatic cylinder. g In the three-dimensional vibration isolation controller based on the spring-damped-inertial-capacitive model, the stiffness constant is replaced with a variable stiffness parameter K(k g To perform vibration isolation parameter compensation, a three-dimensional vibration isolation controller model after vibration isolation compensation is obtained;

[0018] Step 3: Substitute the parameters of the six-dimensional force τ of the vibration isolation platform and the actual motion state of the pneumatic cylinder calculated in Step 1 into the three-dimensional vibration isolation controller model after vibration compensation, and calculate the compensation pose q for vibration reduction.

[0019] Step 4: Calculate the actual pose q of the energy-saving vibration isolation platform using the compensated pose q. d Compensation is performed to generate the target pose. The inverse kinematics solution is then performed on the target pose to obtain the given value l of the extension length of the electric cylinder after vibration isolation compensation. Based on the given value l, the control quantity is calculated to control the electric cylinder to move to the specified position, thereby realizing vibration isolation control.

[0020] Preferably, in step 2, the variable stiffness parameter K(k) g () represents the dynamic stiffness k g The function of dynamic stiffness k g The method of obtaining it is:

[0021]

[0022] Where A is the effective area of ​​the gas pressure inside the pneumatic cylinder on the cylinder lever, V is the effective volume inside the pneumatic cylinder, calculated using the effective area A and the extension / retraction length of the pneumatic cylinder. The extension / retraction length of the pneumatic cylinder piston rod is the same as that of the electric cylinder piston rod, obtained through the servo driver of the electric cylinder; P represents the gas pressure inside the pneumatic cylinder, V t Indicates the effective volume inside the gas tank. This is the derivative of the effective volume inside the pneumatic cylinder.

[0023] Preferably, in step 2, the three-dimensional vibration isolation controller model after vibration isolation compensation is as follows:

[0024]

[0025] Where M represents the generalized mass of the moving part of the energy-saving vibration isolation platform, including the mass of the translational degree of freedom and the inertia of the rotational degree of freedom; B represents the generalized damping of the energy-saving vibration isolation platform, K(k g ) represents the variable stiffness parameter, and q represents the target compensation pose to be solved in step 3. and The first and second derivatives of the actual compensation pose of the energy-saving vibration isolation platform are calculated by the observer based on the actual operating position of the electric cylinder.

[0026] The present invention further provides a control system for an energy-saving vibration isolation platform, the system including a calculator, an inverse kinematics module, a servo driver, a force sensor, a six-dimensional force calculation module, a three-dimensional vibration isolation controller, an observer, and a parameter compensation controller;

[0027] The arithmetic unit is used to apply the vibration-damping compensated pose q from the three-dimensional vibration isolation controller to the given positioning pose q. d Compensation is performed to generate the target pose, which is then output to the inverse kinematics module.

[0028] The inverse kinematics module is used to perform inverse kinematics based on the target pose to obtain the given value l of the extension and retraction length of the electric cylinder with vibration isolation compensation, and output it to the servo driver.

[0029] The servo driver is used to calculate the control quantity u according to the given quantity l, and control the electric cylinder of the energy-saving vibration isolation platform to move to the specified position;

[0030] The observer is used to calculate the speed of the electric cylinder piston rod based on the actual motion state of the electric cylinder. and acceleration The output is sent to the three-dimensional vibration isolation controller;

[0031] The parameter compensation controller is used to acquire the actual motion state of the pneumatic cylinder and estimate the dynamic stiffness k of the pneumatic cylinder caused by the motion. g Send to the three-dimensional vibration isolation controller;

[0032] The three-dimensional vibration isolation controller is used to utilize dynamic stiffness k g Constructing the variable stiffness parameter K(k) g In the spring-damped-inertial-capacitive model, the stiffness constant is replaced by a variable stiffness parameter K(k). g Vibration isolation parameter compensation is performed to obtain a three-dimensional vibration isolation controller model after vibration isolation compensation; data from the observer, the six-dimensional force calculation module and the parameter compensation controller are substituted into the three-dimensional vibration isolation controller model after vibration isolation compensation to calculate the compensation pose q for vibration reduction, and sent to the arithmetic unit to calculate the control target pose.

[0033] Preferably, the parameter compensation controller calculates the dynamic stiffness k. g The formula is:

[0034]

[0035] Where A is the effective area of ​​the gas pressure inside the pneumatic cylinder on the cylinder lever, V is the effective volume inside the pneumatic cylinder, calculated using the effective area A and the extension / retraction length of the pneumatic cylinder. The extension / retraction length of the pneumatic cylinder piston rod is the same as that of the electric cylinder piston rod, obtained through the servo driver of the electric cylinder; P represents the gas pressure inside the pneumatic cylinder, V t Indicates the effective volume inside the gas tank. This is the derivative of the effective volume inside the pneumatic cylinder.

[0036] Preferably, the compensated calculation model obtained by the three-dimensional vibration isolation controller is as follows:

[0037]

[0038] Where M represents the generalized mass of the moving part of the energy-saving vibration isolation platform, including the mass of the translational degree of freedom and the inertia of the rotational degree of freedom; B represents the generalized damping of the energy-saving vibration isolation platform, K(k g ) represents the variable stiffness parameter, and q represents the target compensation pose to be solved. and The first and second derivatives of the actual compensation pose of the energy-saving vibration isolation platform are calculated by the observer based on the actual operating position of the electric cylinder.

[0039] Beneficial effects:

[0040] (1) This invention designs a novel air-balanced electric cylinder, which forms an energy-saving vibration isolation platform with a parallel structure. The electric cylinder and the pneumatic cylinder are parallel and closely connected in parallel. This structure is compact, highly integrated, and has a strong energy-saving effect, thus providing a stronger load capacity for the vibration isolation platform. Moreover, because the electric cylinder and the pneumatic cylinder are closely connected in parallel, and the pneumatic cylinder moves with the electric cylinder, the design stiffness of the electric cylinder vibration isolation model is coupled with the dynamic stiffness of the pneumatic cylinder, thus facilitating the design of the vibration isolation control method for this platform.

[0041] (2) Based on the energy-saving vibration isolation platform composed of the air-balanced electric cylinder, the present invention provides a parameter compensation vibration isolation control method. This method directly compensates the stiffness change disturbance of the pneumatic cylinder of the energy-saving device during the movement of the vibration isolation platform to the three-dimensional vibration isolation controller based on the spring-damping-inertial capacitance model. Compared with suppressing it as a disturbance, it can reduce observation error and improve the vibration isolation control effect.

[0042] (3) When designing the expression of dynamic stiffness, this invention takes into account that the gas exchange cycle between the gas in the cylinder and the gas tank through the connecting pipe is much smaller than the vibration isolation control cycle of the main controller, and assumes that there is no airflow resistance and that the pressure change rate in each gas chamber and its gas tank is the same. Therefore, a simple and easy-to-obtain dynamic stiffness expression is derived, which reduces the difficulty of solving the three-dimensional vibration isolation controller.

[0043] (4) Since the electric cylinder and the pneumatic cylinder are close together, their extension and retraction lengths change synchronously. Therefore, the extension and retraction length, speed and other information of the electric cylinder read from the servo driver can be used as parameters of the pneumatic cylinder to effectively estimate the equivalent stiffness of the cylinder.

[0044] (5) The method of the present invention fully combines the structural characteristics of the vibration isolation platform and the mature application background in the fields of vibration isolation and force measurement. The six-dimensional force on the vibration isolation platform is calculated by the axial force detected by the air balance electric cylinder force sensor, and the vibration isolation effect is achieved by the three-dimensional vibration isolation controller based on the spring-damping-inertia model.

[0045] (6) The present invention adopts a vibration isolation control method based on the inner position loop and uses an electric cylinder position controller to realize high-precision position control of multi-stage electric cylinders, giving full play to the advantages of fast response speed and high control accuracy of electric drive mode.

[0046] (7) The energy-saving vibration isolation platform in this invention can be installed on the carrier through the lower platform through the hole. By introducing a vibration isolation control method with parameter compensation, it can effectively buffer environmental vibration and realize the safe transportation of personnel and equipment in complex environments, thereby expanding the carrying capacity and carrying range. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the energy-saving vibration isolation platform of the present invention;

[0048] Figure 2 This is a side view of the energy-saving vibration isolation platform of the present invention;

[0049] Figure 3 This is a schematic diagram of the air-balanced electric cylinder in the energy-saving vibration isolation platform of the present invention;

[0050] Figure 4 This is a schematic diagram of the parameter compensation vibration isolation control method for energy-saving vibration isolation platforms in this invention;

[0051] Among them, 1-upper platform, 2-first Hooke hinge, 3-inner piston rod, 4-moving auxiliary telescopic sleeve, 5-servo motor, 6-control box, 7-second Hooke hinge, 8-moving auxiliary telescopic rod, 9-fourth Hooke hinge, 10-trunnion, 11-pneumatic cylinder rod, 12-outer piston rod, 13-pneumatic cylinder barrel, 14-air tank, 15-air balance electric cylinder force sensor, 16-third Hooke hinge, 17-lower platform. Detailed Implementation

[0052] This invention provides an energy-saving vibration isolation platform and its control scheme. The core idea is that the actuator in the platform uses a pneumatically balanced electric cylinder. This pneumatically balanced electric cylinder is characterized by its structure consisting of a closely connected electric cylinder and a pneumatic cylinder with parallel axes. The inner piston rods of both cylinders are fixed to the same connecting block, allowing them to operate in conjunction. This structure is compact, highly integrated, and energy-efficient, thus providing the vibration isolation platform with a stronger load-bearing capacity. Furthermore, because the two cylinders are closely connected in parallel, they can be considered coaxial, facilitating the design of a control scheme.

[0053] Furthermore, the control scheme of this invention, when controlling the electric cylinder, collects the operating status of the pneumatic cylinder, estimates the variable stiffness parameter K (kg) generated by the movement of the pneumatic cylinder, and uses this variable stiffness parameter K (kg) to compensate the vibration isolation parameter of the electric cylinder, obtaining the compensated control quantity of the electric cylinder. This control quantity already includes the compensated pose q for vibration reduction. Therefore, using this control quantity can directly achieve the vibration isolation effect without the need for additional suppression operations. It is evident that this control method can identify the stiffness change disturbance of the pneumatic cylinder of the energy-saving device during its movement on the vibration isolation platform and directly compensate it to the three-dimensional vibration isolation controller based on the spring-damping-inertial capacitance model. Compared to suppressing it as a disturbance, this reduces observation errors, improves the vibration isolation control effect, and thus enhances the control accuracy of the actuator.

[0054] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0055] See Figure 1 and Figure 2 The figure illustrates the structure of the energy-saving vibration isolation platform of the present invention. As shown, the energy-saving vibration isolation platform includes an upper platform 1, a lower platform 17, a control component, a sensing component, four air-balanced electric cylinders, three moving pairs, and necessary connecting pipelines.

[0056] The air-balanced electric cylinder includes an electric cylinder and a pneumatic cylinder connected in parallel. The axes of the electric cylinder and the pneumatic cylinder are parallel, and the ends of their inner piston rods are fixed to the same connecting block. The connecting block is connected to a first Hooke hinge 2, and the end of the air-balanced electric cylinder not connected to the connecting block is connected to a second Hooke hinge 7. The air-balanced electric cylinder is connected to the upper and lower platforms through the two Hooke hinges.

[0057] The electric cylinder is the controlled actuator of the vibration isolation platform. As shown in the figure, the electric cylinder includes an inner piston rod 3 and an outer piston rod 12. Each electric cylinder is equipped with a servo motor 5 and driven by it. The servo motor can be mounted on the outer side of the cylinder body of the air-balanced electric cylinder, especially on the outer side of the cylinder body. A force sensor 15 is installed at the bottom of the air-balanced electric cylinder to measure the force on the cylinder. In practice, a strain gauge digital force sensor can be used. The main controller in the control assembly controls the servo motors in the electric cylinders through servo drivers, driving their linear extension and retraction control.

[0058] The pneumatic cylinder includes a cylinder rod 11 and a cylinder barrel 13, with its internal air chamber connected to an air tank 14. Gas at a certain pressure is injected into the cylinder to generate a supporting force along the axial direction of the electric cylinder, balancing the weight of the vibration isolation platform load. This significantly reduces energy loss during the operation of the multi-stage electric cylinder, achieving energy-saving and environmentally friendly effects for the vibration isolation platform. A gas pressure sensor is placed in the air tank 14 connected to the pneumatic cylinder to detect the gas pressure. The air tank 14 can be installed on the lower platform, and it also contains a necessary gas balancing device.

[0059] Figure 3 The specific structure of the pneumatic balance electric cylinder is shown. As illustrated, in this embodiment, the pneumatic balance electric cylinder includes one electric cylinder and two pneumatic cylinders. The pneumatic cylinders are symmetrically distributed on both sides of the electric cylinder, closely attached to the cylinder body. The inner piston rods of the electric cylinder and the two pneumatic cylinders are parallel to each other. The cylinder liners of the electric cylinder and the pneumatic cylinders can be integrally machined or machined separately and welded together. The power of the electric cylinder and the size of the pneumatic cylinders are selected based on the design load and the actual application scenario. The cylinder size can be selected according to the design load mass. For the electric cylinder, its power is selected based on the platform's motion performance requirements and the load.

[0060] The sliding joint of this invention includes connecting parts on both sides of the sliding joint, a sliding joint telescopic rod 8, and a sliding joint telescopic sleeve 4. The sliding joint is a passive mechanism that passively extends and retracts following the movement of the platform. Its function is to support the platform, enhance its structural strength, and restrict its degrees of freedom of movement according to the design. The sliding joints located on the sides of the platform have one end of the telescopic rod connected to the lower platform via a third Hooke hinge 16 through its connecting part, and one end of the telescopic sleeve connected to the upper platform via a trunnion 10. One sliding joint can be provided on each side, or two can be provided on a pair of opposite sides. The sliding joint located in the middle of the platform is called the central sliding joint. One end of the telescopic rod is connected to the lower platform via a fourth Hooke hinge 9 through its connecting part, and one end of the telescopic sleeve is fixedly connected to the upper platform via its connecting part.

[0061] All pneumatically balanced electric cylinders are symmetrically distributed and supported between the upper and lower platforms; the sliding pairs are also supported between the upper and lower platforms. (See also...) Figure 1 In a preferred embodiment of the present invention, the energy-saving vibration isolation platform includes four air-balanced electric cylinders, one central sliding joint, and two lateral sliding joints. The four air-balanced electric cylinders are uniformly arranged in parallel around the platform with identical structures, resulting in high space utilization and strong system rigidity. The four air-balanced electric cylinders are named A, B, C, and D, and are distributed clockwise or counterclockwise at the four corners of the platform. A lateral sliding joint is provided between air-balanced electric cylinders A and B, and between air-balanced electric cylinders C and D. A central sliding joint is located at the center of the platform. The two ends of each air-balanced electric cylinder are connected to the upper and lower platforms via Hooke hinges. The upper end of the central sliding joint is fixed to the upper platform, and the lower end is connected to the lower platform via a Hooke hinge. The upper end of each lateral sliding joint is connected to the upper platform via a single-degree-of-freedom hinge, and the lower end is connected to the lower platform via a Hooke hinge.

[0062] The control components include a main controller and a servo driver, which can be uniformly installed within the control box 6 and placed on the lower platform. In this embodiment, the main controller acquires digital force signals from the strain gauge digital force sensor 15 installed at the bottom of the air-balanced electric cylinder via the CAN bus, and acquires platform attitude and acceleration information from sensors placed on the upper and lower platforms via the serial port, all for vibration isolation control. The control quantity calculated by the main controller using the control algorithm is sent to the servo driver via the CAN bus, which controls the servo motor and simultaneously acquires information such as the extension and retraction length and speed of the multi-stage electric cylinder. The servo driver executes control algorithms such as vector control and active disturbance rejection control to calculate the control quantity, driving the electric cylinder to extend and retract to complete closed-loop control, achieving high-precision vibration isolation control of the platform.

[0063] The connecting pipeline mainly consists of metal pipes and hoses. The gas tank is first connected to the gas-balanced electric cylinder via the metal pipe, and then connected to the cylinder inside the gas-balanced electric cylinder via the hose. The hose has a slack to move with the cylinder and has high flexibility, which can effectively absorb vibration and impact, protecting other components.

[0064] Both the upper and lower platforms are equipped with attitude sensors, placed in the center of the platform, which can be used to measure the platform's attitude and acceleration information. Preferably, the lower platform of the energy-saving vibration isolation platform has through holes, which can be installed on various types of carriers to achieve vibration isolation function.

[0065] This invention proposes a parameter-compensated vibration isolation control method based on the aforementioned energy-saving vibration isolation platform system. This method can identify the stiffness change disturbance of the pneumatic cylinder of the energy-saving device during the movement of the vibration isolation platform and directly compensate it to a three-dimensional vibration isolation controller based on a spring-damping-inertial capacitance model. Compared with suppressing it as a disturbance, this method can reduce observation errors and improve the vibration isolation control effect. The following is a detailed description:

[0066] Assuming the gas inside the pneumatic cylinder is an ideal model, and the pressure and temperature within the gas chamber are uniform, the dynamic equations within the pneumatic cylinder can be expressed as follows:

[0067]

[0068] In the formula, P represents the gas pressure inside the pneumatic cylinder, γ represents the gas polyhedral index, R represents the ideal gas constant, T represents the gas temperature, V represents the effective volume inside the cylinder, and m represents the effective gas mass inside the cylinder. Its derivative. The expression for the dynamic stiffness of the pneumatic cylinder is:

[0069]

[0070] In the formula, k g Let F be the dynamic stiffness of the pneumatic cylinder, F be the axial support force generated by the cylinder, and A be the effective area of ​​the gas pressure inside the pneumatic cylinder on the cylinder lever. Considering that the gas exchange period between the gas inside the cylinder and the gas tank through the connecting pipe is much smaller than the vibration isolation control period of the main controller, and assuming that there is no airflow resistance, and that the pressure change rate in each air chamber and its gas tank is the same, we can derive:

[0071]

[0072] In the formula, V represents the effective volume of the cylinder, V t It represents the volume of the gas tank, and P represents the gas pressure inside the pneumatic cylinder. This is the derivative of the effective volume within the pneumatic cylinder. The effective volume V can be calculated using the effective working area A and the cylinder's extension / retraction length. The extension / retraction length of the pneumatic cylinder piston rod is the same as that of the electric cylinder piston rod (or can be converted based on the structure). Therefore, by combining the extension / retraction length and speed of the electric cylinder read from the servo driver by the main controller, the equivalent stiffness of the cylinder can be effectively estimated.

[0073] Introducing a cylinder dynamic stiffness parameter compensation method into a three-dimensional vibration isolation controller based on a spring-damped-inertial-capacitive model can be expressed as:

[0074]

[0075] In the formula, τ represents the disturbance force of the environment on the vibration isolation platform, which can be obtained by performing six-dimensional force calculation on the force sensor. M represents the generalized mass of the moving part of the energy-saving vibration isolation platform, including the mass of the translational degree of freedom and the inertia of the rotational degree of freedom; B represents the generalized damping of the energy-saving vibration isolation platform. q represents the target compensation pose q of the vibration isolation platform for vibration reduction; The first and second derivatives of the actual compensated pose of the vibration isolation platform can be represented by data (electric cylinder extension length l1) obtained from the servo actuator via an observer and then processed and calculated. Physically, these represent the displacement, velocity, and acceleration measures of the vibration isolation platform's pose. To address coupling issues and other nonlinear disturbances present in parallel platforms, an Extended State Observer (ESO) can be used to observe the platform's pose derivatives. This helps to control disturbances and achieve better vibration isolation.

[0076] K(k g K is a variable stiffness parameter. In existing technologies, this component is a constant K in the expression for the disturbance force τ. This invention expresses it as a function of dynamic stiffness, called the cylinder dynamic stiffness parameter compensation function. Different functions can be selected according to actual needs. Generally, a direct compensation method can be chosen, i.e., K(kg) = K + k g Alternatively, compensation can be achieved through filtering or by selecting a nonlinear function for compensation.

[0077] Figure 3 The schematic diagram of the parameter compensation vibration isolation control method proposed in this invention is shown. The method specifically includes the following steps:

[0078] Step 1: Control the extension and retraction of the electric cylinder in the air-balanced electric cylinder to drive the upper platform of the energy-saving vibration isolation platform to move. At the same time, the pneumatic cylinder in the air-balanced electric cylinder also extends and retracts passively. Collect the actual force F of the electric cylinder. l The six-dimensional force τ of the energy-saving vibration isolation platform is calculated.

[0079] In this step, the dynamic model of the energy-saving vibration isolation platform is constructed, that is, the force balance equation of the energy-saving vibration isolation platform is:

[0080] τ=G·F l

[0081] In the formula, τ∈R 6×1 F represents the generalized six-dimensional force experienced by the energy-saving vibration isolation platform. l ∈R 4×1 The forces acting on each pneumatically balanced electric cylinder, collected by the main controller, are acquired through force sensors; G∈R 6×4 The first-order static influence matrix determined by the energy-saving vibration isolation platform configuration is expressed as follows:

[0082]

[0083]

[0084] In the formula, The force conditions of the four air-balanced electric cylinders are shown. A1 to A4 represent the coordinates of the center of mass of the cross key at the Hooke's hinge connecting the air-balanced electric cylinder to the upper platform of the vibration isolation platform. B1 to B4 represent the coordinates of the center of mass of the cross key at the Hooke's hinge connecting the air-balanced electric cylinder to the lower platform of the vibration isolation platform. The coordinate system takes the center of the lower platform as the origin, the x and y axes are located in the plane of the upper platform, the x-axis is parallel to the long side of the platform, the y-axis is parallel to the short side of the platform, and the z-axis is in a right-handed relationship with the x and y axes.

[0085] In this step, the force balance equation of the vibration isolation platform can be obtained from the force sensor signal F collected by the main controller. l The generalized six-dimensional force τ of the vibration isolation platform is calculated.

[0086] Step 2: Based on the actual motion state of the pneumatic cylinder, estimate the variable stiffness parameter K(k) generated by the motion of the pneumatic cylinder. g In the three-dimensional vibration isolation controller based on the spring-damped-inertial-capacitive model, the stiffness constant is replaced with a variable stiffness parameter K(k g To perform vibration isolation parameter compensation, a three-dimensional vibration isolation controller model after vibration isolation compensation is obtained.

[0087] In this step, the first step is to design a three-dimensional vibration isolation controller based on a spring-damping-inertial capacitance model for the energy-saving vibration isolation platform structure:

[0088]

[0089] In the formula, q, In a physical sense, q represents the electric cylinder's position, velocity, and acceleration; q is the variable to be solved. Obtained by an observer connected to a servo drive; M represents the generalized mass of the moving part of the platform, including the mass of the translational degree of freedom and the moment of inertia of the rotational degree of freedom of the vibration isolation platform; B represents the generalized damping of the energy-saving vibration isolation platform.

[0090] Replace K in the above formula with K(k) g The calculated model after compensation is obtained as follows:

[0091]

[0092] Where K(k) g ) is k g The function, as explained above, is k. g The expression is:

[0093]

[0094] In the above formula, A is the effective area of ​​the gas pressure inside the pneumatic cylinder acting on the cylinder rod, which is a known quantity; V is the effective volume inside the pneumatic cylinder, calculated using the effective area A and the extension / retraction length l2 of the pneumatic cylinder piston, while l2 is equivalent to the extension / retraction length l1 of the electric cylinder piston, which can be obtained from the servo driver. t Let V be the effective volume of the gas cylinder, which is a known quantity. The pressure P is derived from the piston extension and retraction speed of the electric cylinder. P can be obtained from a sensor installed in the pneumatic cylinder or the gas tank. Considering that the gas exchange cycle between the gas in the cylinder and the gas tank through the connecting pipe is much smaller than the vibration isolation control cycle of the main controller, and assuming that there is no airflow resistance, the pressure change rate in each air chamber and its gas tank is the same, the gas tank pressure can be used instead of the pneumatic cylinder pressure.

[0095] Step 3: Substitute the parameters of the six-dimensional force τ of the vibration isolation platform and the actual motion state of the pneumatic cylinder obtained in Step 1 into the three-dimensional vibration isolation controller model after vibration compensation, and calculate the compensation pose q for vibration reduction.

[0096] In this step, the six-dimensional force τ of the vibration isolation platform is calculated, and the velocity and acceleration of the pneumatic cylinder obtained by the observer are used. Substitute the data such as the piston extension length l1 of the electric cylinder, the effective area A, volume V, and air pressure P of the pneumatic cylinder into K(k) g The expression and the formula for the compensated three-dimensional vibration isolation controller are used to calculate the compensated pose q for vibration reduction.

[0097] Step 4: Using the compensated pose q and the given pose q from step 3, we obtain the compensated pose q. d The values ​​are added together to generate the target pose; the inverse kinematics solution is performed on the target pose to obtain the given value l of the extension length of the electric cylinder after vibration isolation compensation; based on the given value l, the control value u is calculated to control the electric cylinder to move to the specified position, thereby achieving the vibration isolation control effect.

[0098] This concludes the process.

[0099] Based on the above method, the present invention also provides a control system for an energy-saving vibration isolation platform, see [link to relevant documentation]. Figure 4 The system includes an arithmetic unit, an inverse kinematics module, a servo driver, a force sensor, a six-dimensional force calculation module, a three-dimensional vibration isolation controller, an observer, and a parameter compensation controller.

[0100] The arithmetic unit is used to adjust the given positioning pose q using the compensation pose q from the three-dimensional vibration isolation controller for vibration reduction. d Compensation is performed to generate the target pose, which is then output to the inverse kinematics module.

[0101] The inverse kinematics module is used to perform inverse kinematics based on the target pose to obtain the given value l of the extension and retraction length of the electric cylinder with vibration isolation compensation, and output it to the servo driver.

[0102] The servo driver is used to calculate the control quantity u based on the given extension length l of the electric cylinder, and control the electric cylinder of the energy-saving vibration isolation platform to move to the specified position.

[0103] The observer is used to generate the derivative of the platform pose based on the actual movement of the electric cylinder. and The output is sent to the three-dimensional vibration isolation controller. The actual movement of the electric cylinder described here is obtained by acquiring the actual extension and retraction length of the electric cylinder from the servo driver and then performing observation and calculation. The calculation process is a conventional technique and will not be detailed here.

[0104] The parameter compensation controller is used to acquire the actual motion of the pneumatic cylinder and estimate the dynamic stiffness k of the pneumatic cylinder caused by the motion. g This data is sent to the three-dimensional vibration isolation controller. The module uses a dynamic stiffness k. g See formula (3) above. The actual movement of the pneumatic cylinder mentioned here includes data such as the piston extension length, effective area A, volume V, and air pressure P. The piston extension length l2 of the pneumatic cylinder is the same as or can be converted to the piston extension length l1 of the electric cylinder.

[0105] A three-dimensional vibration isolation controller is used to utilize dynamic stiffness k g Constructing the variable stiffness parameter K(k) g In the spring-damped-inertial-capacitive model, the stiffness constant is replaced by a variable stiffness parameter K(k). gVibration isolation parameter compensation is performed to obtain a three-dimensional vibration isolation controller model after vibration isolation compensation. Data from the observer, the six-dimensional force calculation module and the parameter compensation controller are substituted into the three-dimensional vibration isolation controller model after vibration isolation compensation to calculate the compensation pose q for vibration reduction. The q is then sent to the arithmetic unit to calculate the target pose for control, thereby realizing vibration isolation control.

[0106] In summary, the present invention has the following characteristics:

[0107] 1. The parallel energy-saving vibration isolation platform based on the air-balanced electric cylinder has the advantages of high load capacity, strong structural rigidity, high control precision and energy saving.

[0108] 2. The integrated air-balanced electric cylinder mechanism features a compact structure and a high degree of integration, providing the vibration isolation platform with stronger load capacity and higher energy-saving effect.

[0109] 3. The vibration isolation platform parameter compensation vibration isolation control method can identify and compensate for disturbances caused by energy-saving devices, thereby improving the vibration isolation control effect and stability.

[0110] 4. The energy-saving vibration isolation platform can be installed on various types of transport vehicles, effectively buffering environmental vibrations and enabling safe transportation of personnel and equipment in complex environments, while also expanding the carrying capacity and range.

[0111] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. An energy saving vibration isolation platform comprising: The upper platform, the lower platform, the control assembly, the sensor assembly, the at least four executing cylinders, and the at least two moving pairs are characterized in that: The executing cylinder is a gas balance electric cylinder; the gas balance electric cylinder comprises a close-coupled electric cylinder and a pneumatic cylinder, the electric cylinder and the pneumatic cylinder are parallel in shaft, and the inner piston rod ends of the electric cylinder and the pneumatic cylinder are fixed on the same connecting block; the connecting block is connected with a first hooke joint, and the end of the gas balance electric cylinder not connected with the connecting block is connected with a second hooke joint; the electric cylinder serves as a controlled executing mechanism, and the pneumatic cylinder is filled with gas of a certain pressure to generate a support force along the axial direction of the electric cylinder to balance the gravity of the load of the energy-saving vibration isolation platform; The gas balance electric cylinders are symmetrically distributed and supported between the upper platform and the lower platform; the moving pairs are supported between the upper platform and the lower platform; The sensor assembly comprises an upper platform posture sensor, a lower platform posture sensor, and a gas balance electric cylinder force sensor; The control component estimates a variable stiffness parameter generated by the pneumatic cylinder due to movement by using a pneumatic cylinder movement state , compensates for the vibration isolation parameter of the electric cylinder by using the variable stiffness parameter , obtains a compensated electric cylinder control quantity, and drives the linear extension and retraction movement of the electric cylinder; The variable stiffness parameter is a function of the dynamic stiffness , where the dynamic stiffness is obtained in the following way: wherein, is the effective area of the gas cylinder lever acted on by the gas pressure in the gas cylinder, is the effective volume in the gas cylinder, calculated using the effective area and the extension length of the gas cylinder, the extension length of the piston rod of the gas cylinder is the same as that of the electric cylinder, and is obtained through the servo driver of the electric cylinder; P represents the gas pressure in the gas cylinder, represents the effective volume in the gas tank, is the derivative of the effective volume in the gas cylinder; Wherein, the variable stiffness parameter The vibration isolation parameter compensation is performed on the electric cylinder, and a three-dimensional vibration isolation controller model after vibration isolation compensation is as follows: wherein, is the six-dimensional force of the vibration isolation platform, represents the generalized mass of the moving part of the energy-saving vibration isolation platform, including the mass of the translational degree of freedom and the inertia of the rotational degree of freedom of the energy-saving vibration isolation platform; represents the generalized damping of the energy-saving vibration isolation platform, is the variable stiffness parameter, is the target compensation pose to be solved, and is the first and second derivatives of the actual compensation pose of the energy-saving vibration isolation platform, which is calculated based on the actual operating position of the electric cylinder by the observer.

2. The energy absorbing vibration isolation platform of claim 1, wherein, The gas balance electric cylinder comprises an electric cylinder and two pneumatic cylinders; the pneumatic cylinders are symmetrically distributed on both sides of the electric cylinder and close to the electric cylinder body, and the inner piston rods of the electric cylinder and the two pneumatic cylinders are parallel to each other.

3. The energy absorbing vibration isolation platform of claim 1, wherein, The energy-saving vibration isolation platform comprises four gas balance electric cylinders, one central moving pair, and two side moving pairs; the four gas balance electric cylinders A, B, C, and D are distributed in the four corners of the platform in a clockwise or counterclockwise direction, one side moving pair is arranged between the gas balance electric cylinders AB, one side moving pair is arranged between the gas balance electric cylinders CD, and a central moving pair is arranged at the center of the platform; the two ends of the gas balance electric cylinder are connected with the upper platform and the lower platform through hooke joints; the upper end of the central moving pair is fixedly connected with the upper platform, and the lower end is connected with the lower platform through a hooke joint; the upper end of the side moving pair is connected with the upper platform through a single-degree-of-freedom hinge, and the lower end is connected with the lower platform through a hooke joint.

4. The energy absorbing vibration isolation platform of claim 1, wherein, The gas balance electric cylinder force sensor is a strain digital force sensor and is installed at the bottom of the gas balance electric cylinder.

5. A method of controlling the energy-saving vibration isolation platform according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: Step 1, control the extension and retraction of the electric cylinder in the air balance electric cylinder to drive the upper platform of the energy-saving vibration isolation platform to move, and the pneumatic cylinder in the air balance electric cylinder is also synchronously passively extended and retracted; collect the actual force of the electric cylinder , and solve the six-dimensional force of the vibration isolation platform ; Step 2, estimating the variable stiffness parameter generated by the pneumatic cylinder due to movement according to the actual movement state of the pneumatic cylinder Replace the stiffness constant with the variable stiffness parameter in the three-dimensional vibration isolation controller of the spring-damping-inerter model To compensate for the vibration isolation parameters, obtain a three-dimensional vibration isolation controller model after vibration isolation compensation; Step 3, the six-dimensional force of the isolation platform calculated in step 1 is substituted into the three-dimensional isolation controller model after compensation, and the compensation pose for vibration reduction is calculated ; the actual motion state of the pneumatic cylinder is substituted into the three-dimensional isolation controller model after compensation, and the compensation pose for vibration reduction is calculated ; Step 4, compensating the pose actual pose of the energy-saving vibration isolation platform compensation, generating a target pose, kinematically inversely solving the target pose, obtaining a given amount of the extension and retraction length of the electric cylinder after vibration isolation compensation ; according to the given amount solving the control amount, controlling the electric cylinder to move to the specified position, thereby realizing vibration isolation control.

6. A control system for the energy saving vibration isolation platform according to any one of claims 1 to 4, characterized in that, The system comprises a calculator, a kinematic inverse solution module, a servo driver, a force sensor, a six-dimensional force calculation module, a three-dimensional vibration isolation controller, an observer, and a parameter compensation controller. The operation device is configured to utilize a compensation pose from the three-dimensional vibration isolation controller for vibration reduction compensate for a given pose to generate a target pose, and output to a kinematics inverse solution module The kinematics inverse solution module is configured to perform kinematics inverse solution according to the target pose to obtain a given length of the telescopic length of the electric cylinder with vibration isolation compensation , and output to the servo driver. The servo drive is configured to determine the control quantity based on the given quantity solving the control quantity , control the electric cylinder of the energy-saving vibration isolation platform to move to the specified position; The observer is configured to calculate the speed of the piston rod of the electric cylinder according to the actual motion state of the electric cylinder and the acceleration of the electric cylinder, and output to the three-dimensional vibration isolation controller. The parameter compensation controller is used to acquire the actual motion state of the pneumatic cylinder and estimate the dynamic stiffness of the pneumatic cylinder caused by the motion. Send to the three-dimensional vibration isolation controller; The three-dimensional vibration isolation controller is configured to utilize dynamic stiffness Constructing variable stiffness parameter Replace the stiffness constant with the variable stiffness parameter in the spring-damping-inerter model Performing vibration isolation parameter compensation to obtain a three-dimensional vibration isolation controller model after vibration isolation compensation; substituting data from the observer, the six-dimensional force calculation module and the parameter compensation controller into the three-dimensional vibration isolation controller model after vibration isolation compensation to calculate a compensation pose for vibration reduction and send to the operation device for calculation of the control target pose.

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