CN105291090A - Parallel type macro-micro high-precision movement platform - Google Patents

Abstract

The invention belongs to the technical field of mechanical design and manufacture, and in particular relates to a parallel macro-micro high-precision motion platform. It is characterized in that the first linear drive system and the second linear drive system are respectively parallel and symmetrically fixed on the front and rear sides of the plane of the base (1), the terminal platform (2) is Y-shaped, and the three tops are respectively connected to the three One end of the same branch chain is connected, the other end of the first branch chain and the second branch chain are hinged on the first linear feed platform (17), and the other end of the third branch chain is hinged on the second linear feed platform (35 ); the two linear feed platforms are respectively connected to the linear guide rails of their respective systems through guide rail sliders, the linear grating ruler is parallel to the linear guide rails, and a plane grating (54) is fixedly installed on the base (1); the flexible hinge unit Embedded in the branch chain, the pressure sensor is fixedly installed at the tail end of the piezoelectric ceramic actuator, and the flexible unit design method of input decoupling is adopted; the invention has the characteristics of high motion precision and high resolution.

Description

A parallel macro-micro high-precision motion platform

technical field

The invention belongs to the technical field of mechanical design and manufacture, and in particular relates to a parallel macro-micro high-precision motion platform.

Background technique

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

Traditional large-scale precision motion platforms are generally driven by servo motors and precision ball screw drives, and some are directly driven by linear motors. The transmission parts of this type of motion platform inevitably have gaps, nonlinear friction, temperature rise, wear, etc. during the motion process, so it is difficult to obtain high motion accuracy, which is generally limited to the micron level. Although the gap can be eliminated by preloading the ball screw, and the friction force can be reduced by using air bearings, which can improve the motion accuracy of the platform to a certain extent, but it is still difficult to meet the application requirements. In order to solve the adverse effects of conventional motion platform transmission parts in the process of motion, a flexible hinge mechanism appears. This type of mechanism transmits motion completely through the material deformation of the flexible hinge, so it has the advantages of no gap, friction and wear, and no lubrication. At the same time, it is driven by a piezoelectric ceramic actuator, and its motion accuracy can reach the nanometer level. widely used in the field. However, limited by the maximum stress of material deformation, the travel of this type of mechanism is very small, generally only tens of microns, which is difficult to meet the needs of large-scale motion.

In order to meet the motion requirements of large stroke and high precision at the same time, a macro-micro motion platform has appeared. The whole system consists of two parts: macro motion and micro motion. The macro motion mechanism can realize a wide range of coarse motion, and the micro motion mechanism compensation system The motion error can achieve high-precision motion, thereby effectively improving the resolution, positioning accuracy and tracking accuracy of the system. The macro-micro dual drive technology provides an effective means for realizing large-stroke, high-precision motion. The current macro and micro platforms all use a single-axis or XY motion platform that is superimposed in series with a micro-motion drive platform, such as the flexible hinge mechanism driven by the piezoelectric ceramic mentioned above. This form of macro-micro platform can achieve high motion accuracy and resolution in a large-scale range, but the macro-micro platform in the form of series superposition has disadvantages such as weak carrying capacity, low natural frequency, and motion error coupling. It is suitable for occasions with light load and lower requirements on dynamic characteristics.

Therefore, how to design a large-scale motion platform with high precision and resolution, high load capacity, and excellent dynamic performance is a challenging and urgent task.

Contents of the invention

In order to achieve the above object, the technical solutions adopted by the present invention are as follows.

A parallel macro-micro high-precision motion platform is characterized in that the first linear drive system and the second linear drive system are respectively parallel to each other and symmetrically fixed on the front and rear sides of the plane of the base 1, the first branch chain, the second The branch chain and the third branch chain are exactly the same; the terminal platform 2 is placed between the first linear drive system and the second linear drive system, the terminal platform 2 is Y-shaped, and the three tops respectively pass through a rotating shaft and three One end of the two branch chains is connected, the other ends of the first branch chain and the second branch chain are respectively hinged on the first linear feed platform 17 through the fixed rotating shaft, and the other end of the third branch chain is hinged at the first linear feed platform 17 through the fixed rotating shaft. On the second linear feed platform 35; the first linear feed platform 17 is connected with the linear guide rail in the first linear drive system by the guide rail slide block, and the second linear feed platform 35 is connected with the second linear drive system by the guide rail slide block The linear guide rails in the middle are connected; the two linear grating scales are respectively parallel to the linear guide rails of the first linear drive system and the second linear drive system; a plane grating 54 is fixedly installed on the base 1;

The macro motion of the linear drive system and the micro motion of each branch chain control the position of the terminal platform 2. After the position value to be achieved by the terminal platform 2 is given, the position of the mechanism is inversely resolved to obtain the first linear motion respectively. Give the motion position amount of platform 17 and the second linear feed platform 35, the motion amount of the first linear feed platform 17 is accurately measured by the first linear grating scale 19, and the motion error of the first linear feed platform 17 The amount is fed back to the first servo motor 4 on the first linear feed platform 17 for full-closed-loop compensation control to ensure the movement position of the first linear feed platform 17; the movement amount of the second linear feed platform 35 passes through the second linear The grating ruler 37 performs accurate measurement, and feeds back the motion error amount of the second linear feed platform 35 to the second servo motor 22 on the second linear feed platform 35 for full-closed-loop compensation control to ensure the accuracy of the second linear feed platform 35. Movement position: The movement error of the terminal platform 2 can be measured through the plane grating 54, and the error amount is compensated by the piezoelectric ceramic actuator in each branch chain.

The specific structure of the first linear drive system includes that the first servo motor support base 3 is fixed on the base 1; the first servo motor 4 is fixedly installed on the first servo motor support base 3; the first ball screw 5 The shaft of the first servo motor 4 is connected through the first coupling 6; the first ball screw 5 is fixed at the end close to the first coupling 6 by the first ball screw fixed on the base 1. 7 is supported and rotated, and the other end of the first ball screw 5 is supported and rotated by the first ball screw floating support seat 8 fixed on the base 1; the first ball screw 5 is sleeved with a first screw The nut 9, the first screw nut seat 10 is fixedly connected with the first screw nut 9; the first linear guide 11 and the second linear guide 12 are respectively arranged on both sides of the first ball screw 5, the first linear guide The guide rail 11 and the second linear guide rail 12 are respectively parallel to the axis of the first linear ball screw 5, and the distance between the first guide rail 11 and the first ball screw 5 and the distance between the second linear guide rail 12 and the first ball screw 5 The distance is equal, the first linear guide rail 11 and the second linear guide rail 12 are fixedly installed on the base 1; the first guide rail slider 13 and the second guide rail slider 14 are arranged on the first linear guide rail 11, The third guide rail slider 15 and the fourth guide rail slider 16 are arranged on the linear guide rail 12; the first linear feed platform 17 is fixedly installed on the first guide rail slider 13, the second guide rail slider 14, the third guide rail slider 15. On the fourth guide rail slider 16 and the first screw nut seat 10, the rotation of the first ball screw 5 will drive the first screw nut 9 to move along the axial direction of the first ball screw 5, so that it can pass The first lead screw nut seat 10 drives the first linear feed platform 17 to move, and the first grating connecting plate 18 is fixedly installed outside the first linear feed platform 17; the first grating reading of the first linear grating ruler 19 The head 20 is fixedly connected with the first grating connecting plate 18 , and the first linear grating scale 19 is fixedly installed on the base 1 and is parallel to the axis of the first ball screw 5 .

The specific structure of the second linear drive system includes that the second servo motor support base 21 is fixed on the base 1; the second servo motor 22 is fixedly installed on the second servo motor support base 21; the second ball screw 23 passes through the first The second shaft coupling 24 is connected with the rotating shaft of the second servo motor 22; the second ball screw 23 is fixed at the end close to the second shaft coupling 24 through the second ball screw fixed support seat 25 fixed on the base 1 Support rotation, the other end of the second ball screw 23 is supported and rotated by the second ball screw floating support seat 26 fixed on the base 1; the second ball screw screw 23 is sleeved with a second screw Nut 27, the second lead screw nut seat 28 is fixedly connected with the second lead screw nut 27; a third linear guide 29 and a fourth linear guide 30 are respectively arranged on both sides of the second ball screw 23, the third linear guide 29 and the fourth linear guide 30 are respectively parallel to the axis of the second ball screw 23, and the distance between the third linear guide 29 and the second ball screw 23 is equal to the distance between the fourth linear guide 30 and the second ball screw 23, The third linear guide rail 29 and the fourth linear guide rail 30 are fixedly installed on the base 1; the fifth guide rail slider 31 and the sixth guide rail slider 32 are arranged on the third linear guide rail 29; There are the seventh guide rail slider 33 and the eighth guide rail slider 34; the second linear feed platform 35 is fixedly installed on the fifth guide rail slider 31, the sixth guide rail slider 32, the seventh guide rail slider 33, the eighth guide rail slider On the block 34 and the second screw nut seat 28, the rotation of the second ball screw 23 will drive the second screw nut 27 to move along the axial direction of the second ball screw 23, so as to pass through the first screw nut seat 28 drives the second linear feed platform 35 to move; the second grating connecting plate 36 is fixedly installed outside the second linear feeding platform 35; the second grating reading head 38 of the second linear grating scale 37 is fixed to the second grating connecting plate connected, the second linear grating ruler 37 is fixedly installed on the base 1 and is parallel to the axis of the second ball screw 23 .

The first linear feed platform 17, the first branch chain, the second branch chain, the first rotating shaft 40-1 and the second rotating shaft 40-2 on the terminal platform 2 jointly constitute a parallelogram mechanism, which limits The degree of freedom of rotation of the terminal platform 2, so the terminal platform 2 only has a degree of freedom of planar movement.

The main part of the branch chain is the hinge base 41-1; the hinge base 41-1 contains a flexible unit, and the micro-motion compensation of the platform is realized by controlling its deformation; the flexible unit drives the platform 41-1- 1. Flexible unit terminal platform 41-1-2, rectangular flexible hinge A 41-1-3 perpendicular to the axis of branch base 41-1, rectangular flexible hinge B 41-1-4, rectangular flexible hinge C 41-1 -5. The rectangular flexible hinge D 41-1-6 is composed of the rectangular flexible hinge E 41-1-7 parallel to the axis of the branch base 41-1; the flexible unit drives the platform 41-1-1 through the rectangular flexible hinge A 41-1-3, rectangular flexible hinge B 41-1-4 are fixedly connected to the hinge base 41-1; the flexible unit terminal platform 41-1-2 passes through the rectangular flexible hinge C 41-1-5, and the rectangular flexible hinge D 41 -1-6 is fixedly connected with the hinge base 41-1; the flexible unit driving platform 41-1-1 and the flexible unit terminal platform 41-1-2 are fixedly connected to each other through the rectangular flexible hinge 41-1-7; The actuator 42-1 is fixedly connected to the flexible unit drive platform 41-1-1 through the actuator connector 43-1; the pressure sensor 44-1 is connected to the piezoelectric ceramic actuator 42-1 through the flange 45-1 The tail is fixedly connected, and the axial direction of the pressure sensor 44-1 is consistent with the axial direction of the piezoelectric ceramic actuator 42-1; the other end of the pressure sensor 44-1 is fixedly connected with the pretension seat 46-1; the pretension seat 46 -1 is fixedly connected to the branch chain substrate 41-1 by bolts, and applies an axial preload to the piezoelectric ceramic actuator 42-1 through the bolt preload; the support plate 47-1 covers the piezoelectric ceramic actuator 42 -1. Actuator connector 43-1, flexible unit driving platform 41-1-1, rectangular flexible hinge A 41-1-3, rectangular flexible hinge B 41-1-4, rectangular flexible hinge E 41-1- 7 and is fixedly connected with the hinge base 41-1, the base of the high-precision length gauge 48-1 is fixed on the support plate 47-1 through the compression cover 49-1; the measuring head of the length gauge 48-1 is fixed on the The clamping unit 50-1 on the support plate 47-1 is fixed to ensure that the measuring head axis of the length gauge 48-1 is parallel to the axis of the piezoelectric ceramic actuator 42-1; the measuring base 51-1 is fixedly installed on the flexible unit terminal platform 41-1-2; the measuring head of the length gauge 48-1 is always in vertical contact with the reference plane of the measuring base 51-1; The weight 52-1 is used to ensure that the branched chain matrix 41-1 is kept horizontal and the moment of inertia is matched during the movement.

The lower end of the terminal platform 2 is fixedly connected with a plane grating reading head 53; a plane grating 54 is fixedly installed on the base 1; a distance of 0.5mm is kept between the plane grating reading head 53 and the plane grating 54; the plane grating reading head 53 The optical path must be along the reticle of the plane grating 54 to ensure normal measurement and reading.

Beneficial effect:

1. The parallel structural form adopted by the macro-micro motion platform of the present invention has the advantages of large carrying capacity, excellent dynamic characteristics, and no accumulation of motion errors;

2. The macro-micro motion platform of the present invention directly transforms the branch chain of the conventional parallel mechanism, embeds the flexible hinge unit into the original branch chain, and actively controls the deformation amount through the piezoelectric ceramic actuator. The micro-motion control of the branch chain can realize the motion compensation of the terminal platform, and at the same time, it can solve the shortcomings of the uncontrollable deformation and vibration of the branch chain of the conventional parallel mechanism, and can achieve high motion accuracy, and the structure is more compact than the macro-micro platform in series form ;

3. In the micro-control branch chain designed by the present invention, a pressure sensor is fixedly installed at the tail end of the piezoelectric ceramic actuator. This installation method can avoid adding moving parts due to the fixed installation of the pressure sensor on the front end of the actuator. Quality, thereby reducing the dynamic operating performance of the platform; at the same time, the pressure sensor can be used for real-time monitoring of the internal force of the branch chain, providing more abundant information for the implementation of the dynamic operating accuracy compensation of the platform;

4. In the micro-control branch chain designed by the present invention, the design method of the input decoupling flexible unit is adopted, which ensures that the piezoelectric ceramic actuator will not be affected by the lateral load during the movement process, thereby improving the movement The precision of the control and the safety during the operation of the actuator are ensured.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of a parallel macro-micro high-precision motion platform in a specific embodiment of the present invention;

Fig. 2 is a schematic structural view of the linear drive system of the present invention;

Fig. 3 is a schematic diagram of the structure of the branched chain part of the present invention;

Fig. 4 is a schematic view of the structure on the support plate in the branch chain of the present invention.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a novel parallel macro-micro high-precision motion platform of the present invention, and Fig. 2 is a structural schematic diagram of a linear drive system of the present invention, as shown in Fig. 1 and 2, the first linear feed system is arranged on the left side of the base 1 Side; the first servo motor support base 3 is fixed on the left side of the base 1; the first servo motor 4 is fixedly installed on the first servo motor support base 3; the first ball screw 5 passes through the first coupling 6 Connected with the rotating shaft of the first servo motor 4; the first ball screw 5 is supported and rotated by the first ball screw fixed support seat 7 fixed on the base 1 at one end close to the first coupling 6, the first The other end of the ball screw 5 is supported and rotated by the first ball screw floating support seat 8 fixed on the base 1; a first screw nut 9 is sleeved on the first ball screw 5, and the first screw nut 9 The nut seat 10 is fixedly connected with the first screw nut 9; the first linear guide rail 11 and the second linear guide rail 12 are respectively arranged on both sides of the first ball screw 5, and the first linear guide rail 11 and the second linear guide rail 12 are respectively parallel to the axis of the first linear ball screw 5, and the distance between the first guide rail 11 and the first ball screw 5 is equal to the distance between the second linear guide 12 and the first ball screw 5, and the first straight line The guide rail 11 and the second linear guide rail 12 are fixedly installed on the base 1; on the first linear guide rail 11, a first guide rail slider 13 and a second guide rail slider 14 are arranged; The third guide rail slider 15 and the fourth guide rail slider 16; the first linear feed platform 17 is fixedly installed on the first guide rail slider 13, the second guide rail slider 14, the third guide rail slider 15, and the fourth guide rail slider 16 and the first lead screw nut seat 10; the first grating connecting plate 18 is fixedly installed outside the first linear feed platform 17; the first grating reading head 20 of the first linear grating scale 19 is connected with the first grating The plate 18 is fixedly connected, and the first linear grating ruler 19 is fixedly installed on the base 1 and is parallel to the axis of the first ball screw 5 .

The second linear feed system is symmetrically arranged on the right side of the base 1, and is parallel to the first linear feed system; a second servo motor support base 21 is fixed at one end on the right side of the base 1; the second The servo motor 22 is fixedly installed on the second servo motor support base 21; the second ball screw 23 is connected with the rotating shaft of the second servo motor 22 through the second coupling 24; the second ball screw 23 is close to the second coupling One end of the shaft device 24 is supported and rotated by the second ball screw fixed support seat 25 fixed on the base 1, and the other end of the second ball screw 23 is floating supported by the second ball screw fixed on the base 1 The seat 26 supports and rotates; on the second ball screw screw 23, a second screw nut 27 is sleeved, and the second screw nut seat 28 is fixedly connected to the second screw nut 27; on the second ball screw 23 The third linear guide rail 29 and the fourth linear guide rail 30 are arranged on both sides respectively, the third linear guide rail 29 and the fourth linear guide rail 30 are respectively parallel to the axis of the second ball screw 23, and the third linear guide rail 29 is connected to the second The distance between the ball screw 23 and the distance between the fourth linear guide 30 and the second ball screw 23 is equal, and the third linear guide 29 and the fourth linear guide 30 are fixedly installed on the base 1; There is a fifth guide rail slider 31 and a sixth guide rail slider 32, and a seventh guide rail slider 33 and an eighth guide rail slider 34 are arranged on the fourth linear guide rail 30; the second linear feed platform 35 is fixedly installed on the fifth linear guide rail. On the guide rail slider 31, the sixth guide rail slider 32, the seventh guide rail slider 33, the eighth guide rail slider 34 and the second lead screw nut seat 28; the second grating is fixedly installed on the outside of the second linear feed platform 35 The connecting plate 36; the second grating reading head 38 of the second linear grating ruler 37 is fixedly connected with the second grating connecting plate, the second linear grating ruler 37 is fixedly installed on the base 1, and is aligned with the axis of the second ball screw 23 parallel.

One end of the first branch chain and the second branch chain is respectively hinged on the first linear feed platform 17 by the first fixed rotating shaft 39-1 and the second fixed rotating shaft 39-2; the first branch chain and the second branch chain The other end of the chain is hinged to one side of the terminal platform 2 through the first rotating shaft 40-1 and the second rotating shaft 40-2 respectively. One end of the third branch chain is hinged on the second linear feed platform 35 through the third fixed rotating shaft 39-3; the other end of the third branch chain is hinged with the other side of the terminal platform 2 through the third rotating shaft 40-3 . The structures of these three branch chains are exactly the same, so the first linear feed platform 17, the first branch chain, the second branch chain and the terminal platform 2 together constitute a parallelogram mechanism, thereby limiting the degree of freedom of rotation of the terminal platform 2, The terminal platform 2 therefore only has two degrees of freedom of movement.

As shown in Figure 3, taking the first branch chain as an example, the composition of the structural branch chain is described as follows:

The main part of the first branch chain is the hinge base 41-1; the hinge base 41-1 contains a flexible unit, and the micro-motion compensation of the platform is realized by controlling its deformation; the flexible unit is driven by the flexible unit Platform 41-1 -1. Flexible unit terminal platform 41-1-2, rectangular flexible hinge A 41-1-3 perpendicular to the axis of branch base 41-1, rectangular flexible hinge B 41-1-4, rectangular flexible hinge C 41- 1-5. The rectangular flexible hinge D 41-1-6 is composed of the rectangular flexible hinge E 41-1-7 parallel to the axis of the branch base 41-1; the flexible unit drives the platform 41-1-1 through the rectangular flexible hinge. Hinge A 41-1-3, rectangular flexible hinge B 41-1-4 are fixedly connected to hinge base 41-1; flexible unit terminal platform 41-1-2 passes through rectangular flexible hinge C 41-1-5, rectangular flexible hinge D 41-1-6 is fixedly connected to the hinge base 41-1; the flexible unit drive platform 41-1-1 and the flexible unit terminal platform 41-1-2 are fixedly connected to each other through the rectangular flexible hinge 41-1-7; piezoelectric ceramics The actuator 42-1 is fixedly connected to the flexible unit drive platform 41-1-1 through the actuator connector 43-1; the pressure sensor 44-1 is connected to the piezoelectric ceramic actuator 42-1 through the flange 45-1 The tail of the pressure sensor 44-1 is fixedly connected, and the axial direction of the pressure sensor 44-1 is kept in line with the axial direction of the piezoelectric ceramic actuator 42-1; the other end of the pressure sensor 44-1 is fixedly connected with the pretension seat 46-1; the pretension The seat 46-1 is fixedly connected to the branch chain base 41-1 by bolts, and the piezoelectric ceramic actuator 42-1 is preloaded with axial preload by the bolts; the support plate 47-1 is fixedly installed on the hinge base 41-1. 1 and covered on piezoelectric ceramic actuator 42-1, actuator connector 43-1, flexible unit driving platform 41-1-1, rectangular flexible hinge A 41-1-3, rectangular flexible hinge B 41- 1-4, right above the rectangular flexible hinge 41-1-7; as shown in Figure 4, the substrate of the high-precision length meter 48-1 is fixed on the support plate 47-1 by the compression cover 49-1; the length The measuring head of the gauge 48-1 is fixed by the clamping unit 50-1 fixed on the support plate 47-1, so as to ensure that the axis of the measuring head of the length gauge 48-1 and the axis of the piezoelectric ceramic actuator 42-1 are mutually Parallel; the measuring base 51-1 is fixedly installed on the flexible unit terminal platform 41-1-2; the measuring head of the length meter 48-1 is always in vertical contact with the reference plane of the measuring base 51-1; A counterweight 52-1 is fixedly connected to the tail end of -1, so as to ensure that the branched chain base 41-1 remains horizontal and achieves a matching moment of inertia during movement.

As shown in Figure 1, the lower end of the terminal platform 2 is fixedly connected with a plane grating reading head 53; a plane grating 54 is fixedly installed on the base 1; a distance of 0.5mm is kept between the plane grating reading head 53 and the plane grating 54, The size of the distance ensures that the plane grating 54 can work normally; at the same time, the optical path of the plane grating reading head 53 must be along the reticle of the plane grating 54 to ensure normal measurement and reading.

The working process of the parallel macro-micro high-precision motion platform described in the present invention is described in detail as follows:

First of all, in order to ensure that the piezoelectric ceramic actuators in each branch chain will not be affected by tension during the movement process, so as not to affect the accuracy of motion control and damage the actuators, it is necessary to apply axial preload to each piezoelectric ceramic actuator load. Take the axial preload application method of the piezoelectric ceramic actuator 42-1 as an example to illustrate: first loosen the fastening bolts at both ends of the preload seat 46-1, and apply the axial load at the tail of the preload seat 46-1. To the thrust, observe the pressure measured by the pressure sensor 44-1, whether it reaches the required axial preload, adjust the thrust until the required preload value is reached, then tighten the preload The fastening bolt on the seat 46-1. After the axial pretension of the piezoelectric ceramic actuator 42-1 is completed, the axial deformation value of the branch chain flexible unit measured by the length gauge 48-1 is set to zero.

After the axial preloading of the piezoelectric ceramic actuators of all branch chains and the initial setting of the deformation of the branch chains are completed, the motion control of the platform can be performed. What the parallel macro and micro motion platform needs to control is the position of the terminal platform 2, which is realized through the macro motion of the linear drive system and the micro motion of each branch chain. After the position value to be achieved by the terminal platform 2 is given, the movement positions of the first linear feed platform 17 and the second linear feed platform 35 can be respectively obtained through the inverse solution of the position of the mechanism. Here, the first linear feed system is taken as an example to illustrate the motion control process after obtaining the position value of the first linear feed platform 17: , since the first linear feed platform 17 and the first lead screw nut 9 are fixedly connected through the first lead screw nut seat 10, the positional amount of the first linear feed platform 17 and the first lead screw nut 9 is Similarly, the axial position of the first lead screw nut 9 on the first ball screw 5 is required to be converted into a position control command of the first servo motor 4, and the first servo motor 4 will drive the motor shaft according to the position control command Rotate, and drive the first ball screw 5 to rotate through the first coupling 6, the rotation of the first ball screw 5 will drive the first screw nut 9 to move along the axial direction of the first ball screw 5, so that The first linear feed platform 17 is driven to move by the first screw nut seat 10 . Since the first grating reading head 20 of the first linear grating ruler 19 is fixedly connected to the first linear feed platform 17 through the first grating connecting plate 18, the amount of motion of the first linear feed platform 17 can pass through the first linear feed platform 17. The linear grating ruler 19 performs precise measurement, and feeds back the motion error amount of the first linear feed platform 17 to the first servo motor 4 for full-closed-loop compensation control to ensure the motion position of the first linear feed platform 17 .

The motion error of the terminal platform 2 can be measured through the planar grating 54, and the error amount is compensated by the piezoelectric ceramic actuator in each branch chain. Here, the first branch chain is used as an example to illustrate the movement error of the terminal platform 2. Compensation process: firstly, the kinematic inverse solution is performed on the motion error of the terminal platform 2 measured by the plane grating 54 to obtain the axial motion amount required to be compensated by the first branch chain, which is exactly what the first branch chain needs output exercise. According to the required output value of motion, the piezoelectric ceramic actuator 42-1 is used to drive the flexible unit in the branched matrix 41 to deform, and the length meter 48-1 is used to measure the length of the flexible unit in the branched matrix 41-1 in real time. Deformation amount, the motion output error amount is fed back to the piezoelectric ceramic actuator 42-1 for full-closed-loop compensation control to ensure the axial motion output amount of the first branch chain. Since the deformation of the flexible unit can achieve very high-precision control, and the selected length gauge can achieve nanometer-level measurement accuracy, on the basis of the macro-motion of the linear feed system, the terminal platform can be realized by using the micro-motion compensation in the branch chain. 2 high-precision movements. In addition, in the process of high dynamic operation, the dynamic control can be combined with the pressure sensors in each branch chain to ensure the platform's more excellent dynamic performance and higher dynamic trajectory tracking accuracy.

What needs to be explained is why only the axial deformation of the flexible unit in each branch chain is considered during the movement process, and why the bending deformation is not considered. Here, the first branch chain is also taken as an example to illustrate: firstly, because the stiffness of the rectangular flexible hinge is similar to It is very small compared to the rest, so the deformation of the rest is ignored compared to the rectangular flexible hinge during the movement; during the movement of the first branch, since the two ends of the first branch respectively pass through the first fixed rotation The shaft 39-1 is hinged with the first rotating shaft 40-1, and its rotational friction force is small, so the first branch chain is considered as a two-force rod, which is mainly affected by the axial force, lateral force and bending force during the movement process. The moment is very small, so the transverse force and bending moment are neglected, so the flexible unit in the branch chain matrix 41-1 mainly deforms in the axial direction; in addition, the rectangular hinge A 41-1-3, the rectangular hinge B 41-1-4, the rectangular hinge The horizontal arrangement of the hinge C 41-1-5 and the rectangular hinge D 41-1-6 makes the axial stiffness of the flexible unit in the hinge base 41-1 smaller, but the lateral stiffness is larger, so it is more likely to occur during the movement. Axial deformation. Based on the above reasons, in the fretting compensation, it is only necessary to control the axial deformation of the flexible units in each branch chain.

In addition, the flexible unit driving platform 41-1-1 and the flexible unit terminal platform 41-1-2 are connected through a rectangular flexible hinge 41-1-7, the main reason is to ensure that the flexible unit terminal platform 41-1-2 1-2 When lateral or torsional deformation occurs, the rectangular flexible hinge 41-1-7 can absorb these displacements, and reduce the displacement when the flexible unit drive platform 41-1-1 is connected with the piezoelectric ceramic actuator 42-1 The lateral load and torque at the place, so as to fully protect the control accuracy of the piezoelectric ceramic 42-1 and the safety in the working process.

Claims (6)

1. A parallel macro-micro high-precision motion platform is characterized in that the first linear drive system and the second linear drive system are respectively parallel to each other and symmetrically fixed on the front and rear sides of the base (1), the first support The chain, the second branch chain and the third branch chain are identical; the terminal platform (2) is placed between the first linear drive system and the second linear drive system, the terminal platform (2) is Y-shaped, and the three top Respectively link to each other with one end of the three branch chains through a rotating shaft, the other ends of the first branch chain and the second branch chain are respectively hinged on the first linear feed platform (17) through the fixed rotating shaft, the third branch chain The other end is hinged on the second linear feed platform (35) through a fixed rotating shaft; the first linear feed platform (17) is connected to the linear guide rail in the first linear drive system through a guide rail slider, and the second linear feed platform (17) The feed platform (35) is connected to the linear guide rail in the second linear drive system through the guide rail slider; the two linear grating scales are respectively parallel to the linear guide rails of the first linear drive system and the second linear drive system; 1) a plane grating (54) is fixedly installed on it; The position of the terminal platform (2) is controlled by the macro motion of the linear drive system and the micro motion of each branch chain. After the position value required by the terminal platform (2) is given, the position inverse solution of the mechanism is used to obtain the first The movement position of the first linear feed platform (17) and the second linear feed platform (35), the movement amount of the first linear feed platform (17) is accurately measured by the first linear grating scale (19), Feedback the motion error amount of the first linear feed platform (17) to the first servo motor (4) on the first linear feed platform (17) to perform full-closed-loop compensation control to ensure that the first linear feed platform The motion position of (17); the amount of motion of the second linear feed platform (35) is accurately measured by the second linear grating ruler (37), and the motion error amount of the second linear feed platform (35) is fed back to the second linear The second servo motor (22) on the feed platform (35) performs full-closed-loop compensation control to ensure the motion position of the second linear feed platform (35); the plane grating (54) can measure the position of the terminal platform (2) Motion error, the error amount is compensated by piezoceramic actuators in each branch chain. 2. A kind of parallel macro-micro high-precision motion platform according to claim 1, characterized in that, the specific structure of the first linear drive system includes that the first servo motor support base (3) is fixed on the base (1 ); the first servo motor (4) is fixedly installed on the first servo motor support base (3); the first ball screw (5) connects with the first servo motor (4) through the first shaft coupling (6) The rotating shaft is connected; the first ball screw (5) is supported and rotated by the first ball screw fixed support seat (7) fixed on the base (1) at one end close to the first coupling (6), The other end of the first ball screw (5) is supported and rotated by the first ball screw floating support seat (8) fixed on the base (1); the first ball screw (5) is sleeved with a second A screw nut (9), the first screw nut seat (10) is fixedly connected with the first screw nut (9); first linear guide rails ( 11) and the second linear guide (12), the first linear guide (11) and the second linear guide (12) are respectively parallel to the axis of the first linear ball screw (5), and the first guide (11) The distance from the first ball screw (5) is equal to the distance from the second linear guide (12) to the first ball screw (5), and the first linear guide (11) and the second linear guide (12) are fixedly installed On the base (1); the first guide rail slider (13) and the second guide rail slider (14) are arranged on the first linear guide rail (11), and the second guide rail slider (14) is arranged on the second linear guide rail (12). Three guide rail sliders (15) and the fourth guide rail slider (16); the first linear feed platform (17) is fixedly installed on the first guide rail slider (13), the second guide rail slider (14), the third guide rail slider On the rail slider (15), the fourth rail slider (16) and the first screw nut seat (10), the rotation of the first ball screw (5) will drive the first screw nut (9) along the The axial movement of a ball screw (5) can drive the first linear feed platform (17) to move through the first screw nut seat (10), and fix it on the outside of the first linear feed platform (17). The first grating connecting plate (18) is installed; the first grating reading head (20) of the first linear grating ruler (19) is fixedly connected with the first grating connecting plate (18), and the first linear grating ruler (19) It is fixedly installed on the base (1) and is parallel to the axis of the first ball screw (5). 3. A parallel macro-micro high-precision motion platform according to claim 1, characterized in that, the specific structure of the second linear drive system includes that the second servo motor support base (21) is fixed on the base (1) On; the second servo motor (22) is fixedly installed on the second servo motor support base (21); the second ball screw (23) passes through the second coupling (24) and the rotating shaft of the second servo motor (22) connected; the second ball screw (23) is supported and rotated by the second ball screw fixed support seat (25) fixed on the base (1) at one end close to the second shaft coupling (24), the second The other end of the ball screw (23) is supported and rotated by the second ball screw floating support seat (26) fixed on the base (1); Two lead screw nuts (27), the second lead screw nut seat (28) is fixedly connected with the second lead screw nut (27); a third linear guide rail (29) is respectively arranged on both sides of the second ball screw (23) ) and the fourth linear guide (30), the third linear guide (29) and the fourth linear guide (30) are parallel to the axis of the second ball screw (23) respectively, and the third linear guide (29) and the second The distance between the ball screw (23) and the distance between the fourth linear guide (30) and the second ball screw (23) is equal, and the third linear guide (29) and the fourth linear guide (30) are fixedly installed on the base ( 1) on; the fifth guide rail slider (31) and the sixth guide rail slider (32) are arranged on the third linear guide rail (29), and the seventh guide rail slider (32) is arranged on the fourth linear guide rail (30) 33) and the eighth guide rail slider (34); the second linear feed platform (35) is fixedly installed on the fifth guide rail slider (31), the sixth guide rail slider (32), the seventh guide rail slider (33) , the eighth guide rail slider (34) and the second screw nut seat (28), the rotation of the second ball screw (23) will drive the second screw nut (27) along the second ball screw (23) ), so that the second linear feed platform (35) can be driven by the first lead screw nut seat (28) to move; a second grating connecting plate ( 36); the second grating reading head (38) of the second linear grating ruler (37) is fixedly connected with the second grating connecting plate, and the second linear grating ruler (37) is fixedly installed on the base (1), and is connected with the second linear grating ruler (37) Two ball screw (23) axes are parallel. 4. a kind of parallel macro-micro high-precision motion platform according to claim 1 is characterized in that, the first linear feed platform (17), the first branch chain, the second branch chain, the terminal platform (2 ) on the first rotation axis (40-1) and the second rotation axis (40-2) together constitute a parallelogram mechanism, which limits the rotational freedom of the terminal platform (2), so the terminal platform (2) only has a plane freedom of movement. 5. A kind of parallel macro-micro high-precision motion platform according to claim 1, characterized in that, the main part of the branch chain is a hinge base (41-1); the hinge base (41-1) contains The flexible unit realizes the micro-motion compensation of the platform by controlling its deformation; the flexible unit is composed of a flexible unit driving platform (41-1-1), a flexible unit terminal platform (41-1-2), and a branched chain matrix (41- 1) Rectangular flexible hinge A (41-1-3), rectangular flexible hinge B (41-1-4), rectangular flexible hinge C (41-1-5), rectangular flexible hinge D (41-1) with axes perpendicular to each other -6), and a rectangular flexible hinge (41-1-7) parallel to the axis of the branched base (41-1) is formed together; the flexible unit driving platform (41-1-1) passes through the rectangular flexible hinge A (41 -1-3), the rectangular flexible hinge B (41-1-4) is fixedly connected with the hinge base (41-1); the flexible unit terminal platform (41-1-2) passes through the rectangular flexible hinge C (41-1-5 ), the rectangular flexible hinge (41-1-6) is fixedly connected with the hinge base (41-1); the flexible unit driving platform (41-1-1) and the flexible unit terminal platform (41-1-2) pass the rectangular flexible The hinges (41-1-7) are fixedly connected to each other; the piezoelectric ceramic actuator (42-1) is fixedly connected to the flexible unit drive platform (41-1-1) through the actuator connector (43-1); The pressure sensor (44-1) is fixedly connected to the tail of the piezoelectric ceramic actuator (42-1) through the flange (45-1), and the axial direction of the pressure sensor (44-1) is connected to the piezoelectric ceramic actuator. The axial direction of (42-1) is consistent; the other end of the pressure sensor (44-1) is fixedly connected with the pretension seat (46-1); the pretension seat (46-1) is fixedly connected to the branch chain matrix ( 41-1), an axial preload is applied to the piezoelectric ceramic actuator (42-1) through bolt preload; the support plate (47-1) covers the piezoelectric ceramic actuator (42-1), Actuator connector (43-1), flexible unit driving platform (41-1-1), rectangular flexible hinge A (41-1-3), rectangular flexible hinge B (41-1-4), rectangular flexible hinge Right above the pentacle (41-1-7) and fixedly connected with the hinge base (41-1), the base of the high-precision length gauge (48-1) is fixed on the support plate (47-1) through the compression cover (49-1). 1) above; the measuring head of the length gauge (48-1) is fixed by the clamping unit (50-1) fixed on the support plate (47-1), so as to ensure that the measuring head axis of the length gauge (48-1) The axis of the piezoelectric ceramic actuator (42-1) is parallel to each other; the measuring base (51-1) is fixedly installed on the terminal platform (41-1-2) of the flexible unit; the measuring base of the length gauge (48-1) The head is always in vertical contact with the reference plane of the measuring base (51-1); a counterweight (52-1) is fixedly connected to the tail end of the branched chain base (41-1), In order to ensure that the branched chain matrix (41-1) maintains a level during the movement and achieves a matching of the moment of inertia. 6. A kind of parallel macro-micro high-precision motion platform according to claim 1, characterized in that, the lower end of the terminal platform (2) is fixedly connected with a plane grating reading head (53); on the base (1) A plane grating (54) is fixedly installed; a distance of 0.5mm is maintained between the plane grating reading head (53) and the plane grating (54); the optical path of the plane grating reading head (53) must be along the reticle of the plane grating (54) , to ensure normal measurements and readings.