232 results about "Motion accuracy" patented technology

The invention discloses an industrial robot predictive maintenance method and system based on multi-source data fusion, and the method comprises the steps: synchronously collecting vibration, current, temperature, acoustic and visual signals through multiple types of sensors, carrying out the filtering, correction and normalization processing, and constructing a multi-modal feature set; cross-modal alignment is realized through time compensation, after dimensionality reduction, a mechanical vibration group, an electrical performance group, a thermodynamic group and a motion precision group are divided, mahalanobis distances of the groups are calculated based on a historical health reference to serve as local anomaly degree scores, weights are dynamically adjusted according to the change rate, and the weights are combined into a preliminary health index. And introducing a nonlinear amplification mechanism to enhance high-value response, adaptively switching smooth intensity according to a degradation trend, and outputting a comprehensive health index. According to the method, comprehensive perception and dynamic evaluation of the operation state of the practical training platform are realized, multi-source heterogeneous information is effectively fused, the limitation of single signal monitoring is overcome, and the anomaly recognition accuracy is remarkably improved.

The invention discloses a motion precision compensation system and method of a numerical control precision automatic lathe, and aims to solve the problems that an existing precision compensation method depends on external calibration, production is interrupted, dynamic errors cannot be responded in real time, and the self-learning closed-loop capability is lacked. The method comprises the steps that servo current, spindle vibration and tool turret position signals are collected in real time; extracting signal features and inputting the signal features into a pre-training model to evaluate a rigidity degradation degree and predict a position deviation; querying a compensation parameter library according to an evaluation result; and injecting the compensation offset into a subsequent numerical control instruction in real time. The system comprises a multi-source signal acquisition module, an edge AI inference engine, a precision state evaluation model, a self-adaptive compensation parameter library and a CNC instruction injection interface. By the adoption of the technical scheme, online real-time precision sensing and self-adaptive compensation without external high-precision equipment and production interruption can be achieved, and machining size consistency and long-term stability are remarkably improved.

The invention discloses a three-axis moving part control method and system based on machine vision. The method comprises the following steps: obtaining a trajectory feature data set from a motion trajectory original data stream; analyzing the difference between the trajectory feature data set and a theoretical trajectory to obtain a deviation distribution report, and calculating the variation amplitude of deviation in combination with historical data and environmental fluctuation conditions to obtain a deviation value matrix; extracting spatial displacement and angle offset data from the deviation value matrix to obtain a basic adjustment amount, and calculating an initial parameter adjustment scheme of each axis in combination with a multi-axis cooperative control constraint condition to obtain a parameter optimization result; and fusing a compensation factor into the parameter optimization result, recalculating the compensation factor for the parameter of which the parameter adjustment result exceeds a preset precision range to obtain a final parameter adjustment scheme, and adjusting the motion parameter of each axis according to the scheme. The method can effectively improve the motion precision and stability of the multi-axis motion part.

The invention provides a double-vector cooperative compensation method and system for a multi-degree-of-freedom motion error of a computer rotating shaft, and the method comprises the following steps: synchronously collecting a translation vector and a rotation vector of the rotating shaft through a sensor, and unifying the data of the translation vector and the rotation vector to the same time-space reference; constructing a coupling error model of translation and rotation vectors, and integrating data of the translation and rotation vectors into a unified six-degree-of-freedom error amount; in combination with a feedforward-feedback mechanism, translation and rotation vector compensation weights are dynamically distributed in a time domain, and a real-time adjustment compensation amount is generated through rolling time domain optimization. The method does not need to depend on a complex parameter identification process of a traditional rotating shaft physical model, six-degree-of-freedom error cooperative compensation can be achieved only through sensor data synchronization and a dynamic optimization algorithm, the method is suitable for computer rotating shafts of different loads and motion scenes, and the motion precision and reliability of equipment are remarkably improved.

The invention relates to the field of industrial robot control, in particular to a trajectory planning method for a self-adaptive vibration suppression mechanical arm. According to the method, a mechanical arm motion vibration signal is monitored in real time through a vibration sensor, and original data are preprocessed to obtain a cleaning vibration signal; calculating vibration characteristic parameters including frequency, amplitude and phase; based on a reinforcement learning algorithm, a reference trajectory is dynamically adjusted through a strategy network according to the vibration characteristic parameters to generate a vibration suppression trajectory, and a reward function takes the vibration parameters as input optimization network parameters; and finally, the vibration suppression track is converted into a joint movement instruction to drive the mechanical arm, and closed-loop control is formed. According to the self-adaptive vibration suppression method, self-adaptive vibration suppression independent of an accurate model is achieved, and the motion precision and stability of the mechanical arm under different working conditions are improved.

The invention discloses a hanging basket motion control method and system based on operation state recognition, particularly relates to the technical field of bridge construction automation, and is used for solving the problem of poor synchronous control of hanging basket movement. According to the method, working conditions are accurately recognized through multi-source sensing data fusion and a finite-state machine, servo system parameter self-adaptive setting is achieved based on working condition parameter mapping, and an anti-interference movement track is generated by adopting a model prediction control algorithm fusing pose feedback and wind load feedforward; walking synchronization and platform stability are achieved through cross coupling control and posture closed-loop fine adjustment, emergency response is provided through the independent safety guarding thread, control and protection double closed loops are formed, and therefore the motion precision, the anti-interference capacity and the intrinsic safety level of the hanging basket under the variable-load and strong-disturbance working conditions are effectively improved, and the safety of the hanging basket is improved. And the energy consumption and the mechanical vibration frequency in the moving process of the hanging basket are reduced.

The invention discloses a joint strengthening contour control method of a robot milling machining system. The joint strengthening contour control method comprises the steps that the robot edge milling machining system is built; a contour error solving strategy based on a switching geometric method and projection factors is established to obtain a contour error compensation target point and a contour error in the motion process of the mechanical arm; an inner ring and outer ring double-layer cascade contour error control strategy is established, a flexible joint mechanical arm system is decomposed into a fast subsystem and a slow subsystem, mechanical arm dynamic system parameters are predicted, an inner ring guarantees the tracking precision of the flexible joint mechanical arm in a joint space based on the fast subsystem and slow subsystem control laws, and an outer ring corrects contour errors. The contour motion precision of the Cartesian space of the mechanical arm is ensured; and adopting a contour error solving strategy and an inner ring and outer ring double-layer cascade contour error control strategy to carry out double-ring cascade contour control on the robot edge milling processing system. The dynamic tracking precision is improved, and the contour precision of the mechanical arm in the moving process is effectively improved.

The invention relates to the technical field of automatic control, in particular to a pathological section automatic adjusting method and system, and the method comprises the following steps: based on the real-time operation state of a microscope stage, analyzing the load and the moving track of the pathological section stage, adjusting the motion parameters of the microscope stage, and responding to the deviation of the section stage. And adjusting position parameters of the slice by combining slice thickness measurement, and generating a platform deck movement adjustment scheme. According to the invention, through real-time analysis of the operation state of the carrying platform, dynamic adjustment of the load and the track, improvement of the motion accuracy and stability, reduction of the positioning error, combination of the slice thickness, optimization of position parameters, enhancement of the processing consistency and efficiency, reduction of dislocation and invalid motion through track optimization monitoring, adjustment of the batch sequence and deformation correction optimization, and equalization of sample distribution. High-throughput operation efficiency is improved, slice offset is dynamically corrected, accurate positioning under different deformation conditions is ensured, automatic adaptability is improved, and errors and time cost are remarkably reduced.

The invention relates to the technical field of motion redundancy parallel robot control, in particular to a method for designing a 2R1T motion redundancy parallel robot high-performance hierarchical synchronous controller based on time delay estimation, which enables a system to estimate current kinetic parameters in real time by introducing a time delay estimation technology, and enables the current kinetic parameters to be estimated in real time in a high-speed motion state. On the basis of the problems of uncertainty, nonlinearity and the like of robot dynamic parameters, dynamic data predicted in real time is used as feed-forward input, so that excessive redundant calculation is avoided, and the efficiency of a control algorithm is optimized; by introducing hierarchical synchronous control, the error difference between redundant degrees of freedom is overcome, the motion precision of a hierarchical driver and the stability of the system are ensured, and the dynamic response of the robot and the robustness of the system are optimized by taking a time delay estimation technology as dynamic feed-forward compensation; and the coordination problem of redundant degrees of freedom is disassembled into a plurality of sub-problems through layered synchronous control, so that the motion coordination and control precision of the robot is improved.

The invention belongs to the technical field of mobile platforms, and discloses a control method and device of a mobile platform. The method comprises the steps that the axle distance and the wheel distance of a mobile platform, the radar distance between a first laser radar and a second laser radar, the radius of Mecanum wheels and the angular speed of each Mecanum wheel of the mobile platform are acquired; determining a spin angle deviation according to the radar distance and a predetermined average value of distance measurement difference values of the first laser radar and the second laser radar; according to the half length of the wheel base, the half length of the wheel track, the theoretical spinning angle and the spinning angle deviation, the actual equivalent spinning radius of the mobile platform is determined; and according to the actual equivalent spinning radius, the radius of the Mecanum wheel and the angular velocity of each Mecanum wheel, the actual spinning angular velocity of the mobile platform is determined by substituting the actual equivalent spinning radius, the radius of the Mecanum wheel and the angular velocity of each Mecanum wheel into a positive operational formula of the mobile platform, and the mobile platform is controlled to move according to the actual spinning angular velocity. According to the invention, the motion precision of rotation of the mobile platform around the z direction can be improved.

The invention discloses a precision detection and compensation method for an automatic tool setting device, which belongs to the technical field of numerical control machining and comprises the following steps of: calibrating position coordinates of a zero point of a laser tracker in a machine tool coordinate system; moving the machine tool to enable the spindle axis and the zero point of the machine tool tracker to be on the same horizontal plane; obtaining coordinates of a reflector rotation circle center position point d on the automatic tool setting device; setting the zero point of the tracker as f, and rotating a machine tool spindle to enable the axis of the radial motion shaft of the automatic tool setting device to be parallel to the straight line fd; a laser tracker is used for obtaining the distribution rule of mechanical transmission errors on the whole stroke of a radial sliding plate of the automatic tool setting device; and carrying out full-stroke positioning precision and repeated positioning precision compensation on the radial sliding plate of the automatic tool setting device until the movement precision of the radial sliding plate meets the expected precision requirement. According to the method, the measuring laser line of the tracker can be ensured to be coaxial with the measured motion axis to the greatest extent, the influence of the motion error of the rotating shaft of the tracker on the measurement precision is reduced, and high-precision position error measurement and compensation are realized.

The invention relates to a side-hung rotating platform real-time counterweight device, a side-hung rotating platform and a control method, and belongs to the technical field of automation equipment. According to the application, the eccentric load torque of the load is monitored in real time, and the counterweight assembly driven by the linear motor is controlled to move according to the eccentric load torque, so that the counterweight force arm is dynamically adjusted, and the reverse counterweight torque is accurately generated to counteract the eccentric load torque. And when the movement compensation is insufficient, the number of the balancing weights can be increased, so that the balancing weight quality is improved. The motion precision can be effectively improved, the equipment is protected, and the stability is improved.

The embodiment of the invention relates to the technical field of robots, and discloses a control method for improving the humanoid degree of a robot, and the method comprises the steps: obtaining a surface electromyogram signal of a corresponding position through an electromyogram detection assembly disposed at a user, and carrying out the preprocessing of the obtained surface electromyogram signal, so as to obtain an electromyogram activity curve; performing feature extraction on the myoelectricity activity curve to obtain myoelectricity time sequence features, and inputting the myoelectricity time sequence features into an action sequence decoding model for recognition to output action categories and action sequences associated with the action categories; and matching with the to-be-executed machine joint state according to the action category and the action sequence associated with the action category, and if the matching is inconsistent, performing updating operation on the to-be-executed machine joint state according to a matching result. According to the scheme, it is ensured that the motion of the robot is highly consistent with the human motion, and the humanoid degree and motion accuracy of the robot are improved.

The invention belongs to the technical field of robot path planning, and particularly discloses a fixed margin removal robot grinding and polishing process and track synchronous planning method and system. Comprising the steps that a robot smooth end face grinding and polishing material removal profile is constructed; the machining allowance of the workpiece is determined, and the curved surface of the surface of the workpiece is subjected to curved surface reconstruction based on the maximum tolerance limitation; with the machining residual height and the smoothness of the technological parameters as targets, force-speed-position machining information of robot grinding is planned on the reconstructed curved surface, and discrete machining point positions and the technological parameters are obtained; expanding the reconstructed curved surface to a four-dimensional form, obtaining a composite track fusing a position component and a process component, and carrying out adaptive interpolation on the composite track to meet the process precision and the motion precision of a processing point; and obtaining a normal vector of the interpolated composite trajectory, and optimizing a tail end redundancy degree of freedom to obtain process parameters and processing poses of synchronous planning. According to the method, matching and optimization of a track field and a process field in robot grinding are achieved.

The invention discloses an industrial robot automatic control system and method, and relates to the technical field of industrial robots, and the system comprises a data management module, a data analysis module, a motion prediction module and a coordination control module. By accurately analyzing key factors, the system can identify core parameters influencing the motion performance of the robot, the adaptability and working efficiency of the robot in a complex environment are optimized, the motion precision and stability are improved, the system predicts the future motion state and track of the robot in a prospective mode by means of a motion prediction model, and the robot motion performance is improved. Potential fault risks are recognized in advance, production interruption is avoided, the service life of the robot is prolonged, motion parameters are dynamically adjusted according to a prediction result, a control strategy is optimized, and the flexibility and execution efficiency of the robot in a multi-task scene are improved, so that the production efficiency and the product quality are remarkably improved, and the labor cost and operation loss are reduced. And greater economic benefits are created for enterprises.

This invention relates to the field of vacuum transmission and sealing technology, specifically a multi-degree-of-freedom manipulator that penetrates the wall of a vacuum chamber, comprising a base flange, a linear drive rod, a welded bellows, a first coupling, and a second coupling. The base flange is installed on the outer wall of the vacuum chamber; the linear drive rod extends into the vacuum chamber through the base flange; the welded bellows is sleeved around the linear drive rod, with its fixed end sealed to the base flange; the first coupling is sealed and fitted around the outer circumference of the linear drive rod; the second coupling radially moves with the first coupling and is sealed to the moving end of the welded bellows, with its inner diameter larger than the diameter of the linear drive rod, forming a radial clearance. This invention eliminates the radial runout of the welded bellows through the radially moving fit between the first and second couplings, preventing it from interfering with the motion accuracy of the linear drive rod and simultaneously improving the fatigue life of the bellows.

The invention discloses cutting equipment for steel roller production, which is used for a to-be-cut steel roller, and is characterized by comprising a laser device, a cutting device, a cutting device and a cutting device, and the laser device is used for the to-be-cut steel roller; the motion platform is used for controlling the position movement between the steel roller to be cut and the laser; the roller restraining module is arranged on the moving platform and used for restraining and limiting the steel roller to be cut; and non-contact support is formed, so that mechanical friction is eliminated, and submicron-level motion precision is realized.

The present application discloses an angle adjustment mechanism and imaging system, belonging to the technical field of adjustment devices. The angle adjustment mechanism comprises: an outer frame having a sliding groove formed along a first direction; an inner ring adjustment member movably disposed within the outer frame; a lever having a first end connected to the inner ring adjustment member and a second end formed with a raised portion whose width is greater than the width of the middle portion of the lever; a slider disposed within the sliding groove and having a groove formed therein. The second end of the lever is positioned within the groove, and the raised portion contacts opposite side walls of the groove in the first direction; and an adjustment rod connected to the slider. The adjustment rod is configured to drive the slider to slide along the sliding groove in the first direction, causing the slider to push the second end of the lever in the first direction, thereby driving the inner ring adjustment member to move within the outer frame. According to the angle adjustment mechanism of the present application, lost motion is eliminated during direction switching, thereby improving motion accuracy and ensuring the precision of the rotation angle control of the inner ring adjustment member.

The present invention discloses a compact multi-axis precision motion stage; it comprises, from bottom to top, a primary stage, a secondary stage, and a tertiary stage. The primary stage is an x-axis linear motion stage, the secondary stage is an Rx rotary motion stage, and the tertiary stage comprises a Y and Z linear motion stage and an Rz rotary motion stage. The motion stage of the present invention features a compact structure, a large motion range, a small footprint, and strong installation adaptability. The arrangement of suitable actuators as drivers enables high motion accuracy and robustness on each axis, while also offering low power consumption, non-magnetic properties, low heat generation, and high reliability.

The invention relates to an air floatation motion platform which comprises a base, a Y-direction motion assembly arranged in the Y-axis direction is connected to the base, and an X-direction motion assembly arranged in the X-axis direction is slidably connected to the Y-direction motion assembly. The moving accuracy is remarkably improved, the problems that the gravity center is high and the orthogonality is difficult to adjust are solved, and the accuracy of the moving platform is improved. And meanwhile, through the first cross beam, the second cross beam, the first fixing block and the second fixing block, rapid adjustment can be achieved, the precision is improved, and meanwhile the adjustment efficiency can be improved.

The invention relates to the technical field of mechanism science, in particular to a motion decoupling and position positive solution symbolization one-translation and one-rotation parallel mechanism which comprises a static platform and a movable platform, and a first simple branch chain and a second simple branch chain are connected between the static platform and the movable platform; the first simple branch chain is formed by connecting a first moving pair and a first rotating pair in series, and the second simple branch chain is composed of a second moving pair, a second rotating pair, a third rotating pair, a fourth rotating pair and a fifth rotating pair. Rotation of the movable platform around the axis of the first rotating pair is determined by input of the first moving pair and the second moving pair, motion decoupling is achieved, and a symbolic position positive solution is easy to obtain. The whole parallel mechanism is composed of seven kinematic pairs, the number of the kinematic pairs is relatively small, potential machining errors, assembling gaps and the number of abrasion points can be reduced, the error transmission path between the kinematic pairs can be reduced, errors accumulated on the movable platform can be reduced, and the output motion precision of the movable platform can be improved.

This utility model discloses a multi-degree-of-freedom motion platform and optical detection system, comprising: a base; a first moving component, which includes a first support platform, a first linear module, and a first air-bearing structure, wherein the first linear module is drivenly connected to the first support platform, and the first air-bearing structure blows air toward the base to create a gap between the first support platform and the base; and a second moving component, which includes a second support platform, a second linear module, and a second air-bearing structure, wherein the second linear module is mounted on the first support platform and drivenly connected to the second support platform, and the second air-bearing structure blows air toward the first support platform to form an air film between the first support platform and the second support platform. This utility model improves the motion accuracy and speed of the device by reducing the weight borne by the first linear module through the first air-bearing structure blowing air toward the base.

The application relates to an automatic feeding method of multi-specification plugs, belongs to the technical field of non-standard automation equipment, and solves the problem that the existing aircraft plugs cannot be automatically fed. The application comprises the following steps: making a plug assembly sequence list; filling the plugs and making a plug position information table; and connecting a plug feeding part and a support. The application can ensure the position accuracy and movement precision of the whole feeding device, multiple components work cooperatively, the automatic feeding of the plugs is realized, the jacking head cannot run out of range, the feeding device is prevented from malfunctioning, and the use safety is ensured.

This disclosure relates to improvements in adaptive motion vector difference resolution in intra-block copy mode. A method for video processing includes: determining an allowable set of motion precisions for motion information during a conversion between a current video block and a bitstream representation of the current video block, wherein the current video block is encoded in intra-block copy (IBC) mode, wherein the motion information includes at least one of motion vectors, motion vector predictions, and motion vector differences; and performing the conversion based on the determined set of motion precisions.

The utility model discloses an interactive hand clamping mechanism, which comprises an X-axis cross beam, an X-axis cross beam, an X-axis cross beam, a Y-axis cross beam, a Y-axis cross beam, a Y-axis cross beam and a Y-axis cross beam, the upper clamping hand module reciprocates along the X-axis cross beam in the upper clamping hand moving area; the upper clamping hand module comprises an upper clamping hand, an upper clamping hand X-axis translation seat and a Y-axis driving unit; the Y-axis driving unit drives the upper clamping hand to extend towards one side part of the X-axis cross beam to wait for materials and to retract to avoid one side part deviating from the X-axis cross beam; the lower clamping hand module reciprocates along the X-axis cross beam in the lower clamping hand moving area; the lower clamping hand module comprises a lower clamping hand, a lower clamping hand X-axis translation seat and a Z-axis driving unit for driving the lower clamping hand to move in the Z-axis direction relative to the lower clamping hand X-axis translation seat; and the Z-axis driving unit drives the lower clamping hand to ascend for material waiting and descend for avoiding. The structural compactness, the movement precision, the working stability and the structural reliability are improved.

This application discloses a motion accuracy compensation system and method for CNC Swiss-type lathes, aiming to solve the problems of existing accuracy compensation methods that rely on external calibration, interrupt production, cannot respond to dynamic errors in real time, and lack self-learning closed-loop capabilities. The method includes: real-time acquisition of servo current, spindle vibration, and turret position signals; extraction of signal features and input into a pre-trained model to assess the degree of stiffness degradation and predict position deviation; querying a compensation parameter library based on the assessment results; and real-time injection of the compensation offset into subsequent CNC commands. The system includes a multi-source signal acquisition module, an edge AI inference engine, an accuracy status assessment model, an adaptive compensation parameter library, and a CNC command injection interface. By adopting the above technical solution, this application can achieve online real-time accuracy perception and adaptive compensation without external high-precision equipment or production interruption, significantly improving machining dimensional consistency and long-term stability.

The application belongs to the technical field of automatic assembly, and particularly relates to a compact nut automatic tightening equipment. The compact nut automatic tightening equipment comprises a tool lifting system, a tool horizontal feeding system, an indexing positioning system, a tightening core system and a supporting system. The tool horizontal feeding system, the indexing positioning system and the tool lifting system are sequentially connected from top to bottom. The tightening core system is connected with the horizontal feeding system. The tool lifting system is used for completing lifting movement of the tightening core system. The tool horizontal feeding system is used for completing horizontal feeding of the tightening core system. The indexing positioning system is used for completing rotation indexing of the tightening core system. The tightening core system is used for completing power closed-loop output of tightening. The supporting system is used for completing support of the bottom blade disc axis surface of the engine rear shaft by the tightening core system. The application has the characteristics of high automation degree and high motion precision, avoids manual misoperation, and guarantees the consistency, high tightening precision and high tightening efficiency of each nut.

This invention relates to a humanoid robot, specifically a parallel rotating mechanical joint based on a ring-shaped guide rail, mimicking the rotation of a human neck. The aim is to provide a parallel rotating mechanical joint based on a ring-shaped guide rail to achieve three degrees of freedom in the movement of a biomimetic human neck joint while ensuring high rigidity and motion accuracy. Furthermore, the joint features a simplified structure, good support performance, and sufficient movement space for the neck joint. The technical solution is a parallel rotating mechanical joint based on a ring-shaped guide rail, characterized by: a head motion platform, a neck ring-shaped guide rail base, and three PSS (Personal Stability Support) link branches connected in parallel between the head motion platform and the neck ring-shaped guide rail base; the center of the head motion platform and the center of the neck ring-shaped guide rail base are connected by a composite rotating shaft.

The invention discloses a structural parameter optimization method of a Stewart platform, and belongs to the technical field of parallel robots. The method comprises the following steps: firstly, establishing a mathematical model of a Stewart platform, carrying out degree-of-freedom analysis on the platform, and establishing a kinetic equation based on a positive and inverse kinematics relationship and a Lagrange method; then determining an optimization target which covers a working space, rigidity, motion precision and stability; on this basis, a particle swarm optimization (PSO) algorithm is adopted to carry out global optimization on key parameters such as branch length, platform layout, driver position and the like, and a fitness function is utilized to comprehensively evaluate platform performance; and finally, inputting an optimization result into finite element analysis (FEA) and multi-body dynamics simulation (MBD) software for verification. Experimental results show that the working space of the Stewart platform can be remarkably expanded, the motion precision and rigidity of the Stewart platform are improved, stress distribution is improved, and the overall stability is enhanced. The method breaks through the limitation of traditional empirical design and single-target optimization, has the advantages of high optimization efficiency, high global search capability and high convergence speed, is suitable for scenes such as flight simulators, precision machining and spaceflight test platforms, and has wide engineering application value.

The present invention relates to the fields of mechanical transmission and robotics, and in particular to a single-degree-of-freedom spatial remote motion center mechanism. The mechanism comprises a base, a motion platform, and a symmetrical connecting rod group connecting the base and the motion platform; the symmetrical connecting rod group comprises a right connecting rod group and a left connecting rod group; the right connecting rod group and the left connecting rod group each have three revolute pairs whose axes intersect at one point, and the intersection points of the axes of the three revolute pairs of the right connecting rod group and the left connecting rod group are respectively PA and PB; the motion platform can achieve single-degree-of-freedom rotational motion around the line connecting PA and PB. The mechanism of the present invention has few parts, a simple structure, and good rigidity, and can ensure good motion accuracy.