A point cloud trajectory planning method for a robot polishing system

Abstract

The present invention discloses a point cloud trajectory planning method for a robot polishing system, comprising: building a robot polishing hardware system, obtaining point cloud data of a curved composite component under the robot base coordinate; obtaining accurate and streamlined point cloud data based on point cloud preprocessing, obtaining processing posture micro-segments using a point cloud processing algorithm, building a posture optimization function based on robot posture constraints, and obtaining the optimal processing posture using a genetic algorithm; establishing a posture transition model and speed constraints for forward posture initialization, setting up posture synchronization judgment conditions to determine the information of the segment to be lengthened, and proposing a T-type speed-time synchronization method for posture synchronization adjustment and planning real-time processing trajectories, thereby realizing efficient robot polishing. The present invention obtains and optimizes processing postures based on real-time point clouds, realizing posture synchronization forward planning; solving the problem of errors in trajectory generation using digital models, avoiding sudden posture changes, meeting processing requirements, and improving processing efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of robot polishing control, and particularly relates to a point cloud trajectory planning method for a robot polishing system. BACKGROUND

[0002] Curved composite components are widely used in aerospace, automotive industry and other high-tech fields, and can provide high specific strength, corrosion resistance and designability. After the laying forming of the composite component, surface wrinkles caused by vacuum flow guide pipeline and patch lap operation often exist. These wrinkles will affect the appearance, structural integrity and functional performance of the final product, and polishing removal is an important processing step in the post-processing of curved composite components.

[0003] In order to meet the polishing requirements of the complex curved surface structure of the composite component, avoid the harm of polishing composite powder to the workers, and improve the intelligentization and automation degree of processing, industrial robots are widely used in industrial processing field due to the advantages of automation, flexibility and stability, and have a good development trend in the field of polishing and polishing.

[0004] Traditional robots generally obtain processing trajectories through offline programming, that is, processing micro-segments are obtained according to theoretical numerical models. However, the curved composite component cannot be accurately positioned, resulting in that the actual situation does not match the numerical model, so the offline programming method cannot meet the actual processing requirements. However, the point cloud data accurately records the three-dimensional information of the actual situation, and can solve the problem of deviation between the curved composite component and the theoretical numerical model. In addition, in the robot pose synchronous planning, considering the problem of frequent start and stop of equipment caused by zero turning speed of the processing micro-segment and the problem of excessive attitude change caused by not considering the attitude constraint of pose synchronization, the curved composite component needs to be planned with a smoother and more accurate trajectory. SUMMARY

[0005] In view of the problems in the prior art, the application provides a point cloud trajectory planning method for a robot polishing system, which obtains and optimizes the processing pose according to the actual point cloud, determines the speed time synchronization method, realizes the pose synchronous real-time look-ahead process of the robot analysis, solves the problem that the numerical model cannot be accurately positioned, avoids attitude mutation, meets the curved polishing processing requirements of the robot system, and improves the polishing processing speed of the robot.

[0006] In order to achieve the above technical purpose, the application provides the following technical scheme:

[0007] A point cloud trajectory planning method for a robot polishing system, specifically comprising:

[0008] S1, establish the hardware configuration of the industrial robot polishing processing system, including an industrial robot, a constant force flange, an eccentric polisher, a binocular vision measuring device, a curved surface composite component and a placing table; the constant force flange is fixedly connected with the eccentric polisher and is installed at the end of the robot, is responsible for polishing processing, and controls the processing force to be stable at a constant value; the curved surface composite component is placed on the placing table; the binocular vision measuring device is placed on the ground at a certain distance from the processing area, so as to ensure that the curved surface composite component, i.e. the component to be processed, is in an optimal position in the field of view;

[0009] S2, a coordinate system is established by using the binocular vision measuring device, and three-dimensional point cloud information corresponding to the component to be processed is obtained by using a ball sweep in the binocular vision measuring device;

[0010] S3, the three-dimensional point cloud information obtained in step S2 is preprocessed by filtering and sampling, and the processing position and posture of the robot are obtained by using a point cloud algorithm processing method;

[0011] S4, according to the processing posture obtained in step S3, the robot processing posture is optimized by using a robot processing posture constraint condition, and a final robot posture optimization result is obtained;

[0012] S5, according to the posture result obtained in step S4, N segments of posture look-ahead trajectory segments are selected, N≥3, and initial parameter setting is performed according to a posture transition model and a speed constraint;

[0013] S6, the planning time of linear segments and circular arc segments of the robot position and posture is obtained by using a T-type speed interpolation method, and the synchronization of the position and posture is judged to determine the information of the segment to be synchronized and lengthened;

[0014] S7, based on the posture synchronization judgment result of step S6, the position and posture of the circular arc segment and the linear segment are adjusted by using a speed synchronization method respectively;

[0015] S8, whether the last time posture synchronization look-ahead is judged, and different data output and storage decisions are made; the output data plans the processing trajectory in real time according to the adjusted speed.

[0016] Further, step S2 specifically includes:

[0017] The robot base coordinate system, the workpiece coordinate system, the wrist coordinate system and the tool coordinate system are established by using the binocular vision measuring device; the point cloud of the component to be processed relative to the workpiece coordinate system is obtained by using a ball sweep in the binocular vision measuring device; and the three-dimensional point cloud information of the component to be processed in the robot base coordinate system is obtained according to the conversion relationship of the workpiece coordinate system relative to the robot base coordinate.

[0018] Further, step S3 specifically includes:

[0019] S31, remove noise data by statistical filtering; statistics of the neighborhood of each point is performed to obtain a result of approximate Gaussian distribution, and the average distance d and the standard deviation of each point to all adjacent points are calculated σ , a standard deviation coefficient std is determined, and points with an average distance outside the standard range D=d+stdx is removed, that is, points that are "dispersed" compared with the surrounding adjacent points are removed;

[0020] S32, obtain simplified point cloud data by voxel downsampling method, determine rows, columns and layers according to the maximum and minimum values of the point cloud and the grid size, and place each point cloud data in the corresponding grid according to the coordinates, and calculate the centroid of the non-empty grid to replace all points in the voxel;

[0021] S33, the point cloud layer is intercepted by two planes with a distance d, the point cloud layer is projected to the middle plane of the two planes by projection to obtain initial path points; NURBS curve fitting is used to fit the path points to obtain discrete machining positions with equal step length;

[0022] S34, by point cloud normal vector algorithm, the plane fitted by the point cloud in the radius R sphere range of the machining position obtained in step S33 is calculated, any key point on one side of the curved surface is selected to obtain the normal vector of the fitted plane towards the key point as the normal vector of the machining position;

[0023] S35, the normal vector obtained in step S34 is taken as the z axis, and the x and y axes are set arbitrarily under the principle of satisfying the xyz right-handed coordinate system; the Euler angle of the xyz coordinate system relative to the robot base coordinate system is calculated; the Euler angle and the coordinates of the machining position obtained in S33 are taken as the machining pose; the robot base coordinate system is established by the binocular vision measurement device.

[0024] Further, step S4 specifically comprises:

[0025] S41, calculate the joint angle corresponding to different robot end poses according to the robot inverse kinematics, obtain the joint range according to the robot technical parameters, take the ratio of the position of the joint to the median value of the joint range as the ratio of the joint motion range, and take it as the robot joint index R θ , as follows:

[0026]

[0027] wherein, n represents the number of robot joints, θ imin represents the minimum limit of joint i, 1≤i≤6, θ imax represents the maximum limit of joint i, θ imid represents the intermediate limit of joint i, and θ i represents each joint angle, and θ imin≤ θ i ≤ θ imax ;

[0028] S42, the operability is taken as an inverse to obtain a dexterity index R of the robot ω , which is expressed by a formula as follows:

[0029]

[0030] Wherein, is the operability, and J(θ) is a Jacobian matrix;

[0031] S43, based on steps S41 and S42, dimensionless variables of the joint index and the dexterity index of the robot are obtained, a nonlinear objective function for obtaining an optimal value of the robot machining posture is established by taking a robot end posture change angle corresponding to a machining path point as a variable, a genetic algorithm is selected to optimize and solve the objective, and an optimal posture change angle is obtained; and the obtained posture is taken as a final robot machining posture.

[0032] Further, the step S5 specifically includes:

[0033] S51, position transition initialization is performed; for initialization of the first look-ahead, a maximum error under a circular arc radius is obtained, one half of a track segment is taken as a circular arc radius of the circular arc transition, a smaller value in the two radii is taken as a value of the circular arc radius initialization, and a first initial speed and a last end speed are set to 0; a circular arc segment speed constraint is set according to acceleration, normal acceleration and maximum speed; a speed and acceleration constraint of a straight line segment is set according to maximum speed and maximum acceleration respectively; and a connection point constraint condition of the straight line segment and the circular arc segment is set according to a speed and acceleration constraint of the circular arc segment.

[0034] S52, for initialization of a non-first look-ahead, a start speed is set according to an end speed output by the last look-ahead, and preset modes of the remaining variables are the same as those of the first look-ahead in the step S51;

[0035] S53, based on the steps S51 and S52, a boundary speed determination method is formulated according to a straight line two-end boundary speed to judge a speed type; in an acceleration process, an end speed constraint is reduced to a maximum speed that can be accelerated by a start speed of the straight line segment; in a deceleration process, a start speed constraint is reduced to a maximum speed that can be reversely accelerated by an end speed of the straight line segment; and a parameter setting of the position transition initialization is updated according to the speed constraint.

[0036] S54, similarly, posture transition initialization is performed according to the processes described in the steps S51-S53.

[0037] More specifically, step S51 is specifically:

[0038] P n1 , P n2 , P n3 , P n4 , P n5 , P n6 , P n7 P0 is the end point of the position micro-segment, P n2 is the center point of the transition circular arc, P1, P2 are the tangent points of the position transition circular arc and the position straight segment, P3, P4 are the position points of adjacent two interpolations, P5 is the intersection point of P0P n2 and the circular arc, P6 is the intersection point of P3P4 and P0P n2 , P7 is the intersection point of P1P2 and P0P n2 , L1, L2, L3, L4, L5, L6 are the position segments P n1 P n2 , P n2 P n3 , P n3 P n4 , P n4 P n5 , P n5 P n6 , P n6 P n7 corresponding length; P n1 , P n2 , P n3 , P n4 , P n5 , P n6 , P n7 P0 is the end point of the position micro-segment, P n2 is the center point of the transition circular arc segment, P1, P2 are the tangent points of the position transition circular arc segment and the position straight segment, P3, P4 are the position points of adjacent two interpolations, P5 is the intersection point of P0P n2 and the circular arc, P6 is the intersection point of P3P4 and P0P n2 , P7 is the intersection point of P1P2 and P0P n2 , L1, L2, L3, L4, L5, L6 are the position segments P n1 P n2 , P n2 P n3 , P n3 P n4 , P n4 P n5 , P n5 P n6 , P n6 P n7The corresponding length; for the position micro segment, the maximum speed of the straight line segment and the arc segment is v max , the maximum angular velocity is w max , the maximum acceleration is a max , maximum angular acceleration α max , set the maximum normal acceleration equal to the maximum acceleration;

[0039] For the position endpoint P n2 Corresponding to the transition arc segment, set P3P4 perpendicular to P0P n2 ; Set the bow height error generated at the highest speed to e ch , namely P5P6; set the contour error generated by interpolation at the highest speed to e co , that is, P n2 P6; Set line segment P n1 P n2 With line segment P n2 P n3 The angle between them is θ, that is, ∠P n1 P n2 P n3 ;

[0040] The position arc transition in the pose arc transition model, where the arc error radius r err The formula is expressed as:

[0041] r err / (e co -e ch +r err )=sin(θ / 2);

[0042] r err =sin(θ / 2)×(e co -e ch ) / (1-sin(θ / 2));

[0043] When the transition arc radius is too long, select half of the smaller segment of the adjacent line segment as the transition arc constraint to meet the transition length requirement of the straight line segment and determine the arc radius r len for:

[0044] r len =min(L1,L2) / (2tan(θ / 2));

[0045] According to the arc error radius and arc radius, the preset transition arc radius r is obtained n =min(r err ,r len );

[0046] According to the normal acceleration of the arc and the preset transition arc radius, the allowable speed of the arc segment is:

[0047]

[0048] Further, the velocity constraint of the arc segment is v n = min(v rmax ,v max ), and the arc radius and velocity constraint of the other position end point can be obtained in the same way.

[0049] The same as above for the pose micro-line segment.

[0050] Further, step S6 is specifically:

[0051] The position and pose planning time of the straight line segment and the arc segment is obtained by using T-type velocity interpolation, the pose planning time is compared and analyzed, it is judged whether the shorter time corresponds to the position segment or the pose segment, and the type corresponding to the time lengthening segment is determined, that is:

[0052] In the process of pose synchronization in each trajectory segment, the position planning time T v and the pose planning time T w are obtained by T-type velocity planning, and the following three situations may occur:

[0053] When T v = T w , the position and pose planning time are consistent, and no pose synchronization adjustment is performed.

[0054] When T v > T w , the position planning time is greater than the pose planning time, and the pose planning time is synchronized and lengthened.

[0055] When T v < T w , the position planning time is less than the pose planning time, and the position planning time is synchronized and lengthened.

[0056] Further, step S7 specifically includes:

[0057] S71, according to the pose synchronization requirement, a T-type velocity time synchronization method is determined; different pose synchronization methods are obtained by setting time limits; the initial pose synchronization method is set in the case where the end velocity does not change, and the changed pose synchronization method is set in the case where the end velocity changes.

[0058] S72, all pose arc segments are adjusted, the maximum velocity v halfS reached by moving half of the arc path is taken as the arc start and end velocity limit, the arc start and end velocity limit is obtained as v = min(v n ,v halfS ), wherein v nFor the circular segment speed constraint, to ensure that the start and end speed of the circular segment position and attitude satisfies the pose synchronization requirement regardless of how the speed drops, the initial pose synchronization method described in step S71 is used for planning;

[0059] S73, for the pose synchronization of the straight line segment, for the time period that needs to be lengthened, first plan with the initial pose synchronization method; when the initial pose synchronization method does not meet the synchronization time requirement, use the change pose synchronization method to plan; if the synchronization time requirement is still not met, then adjust the speed according to the specific situation, that is:

[0060] If the current planned straight line segment is not the first straight line segment in the lookahead segment, adjust the straight line segment speed, and accelerate from 0 to the maximum speed according to half of the straight line segment path as the initial and final speed of the straight line segment; if the straight line segment is the first straight line segment in the lookahead segment at this time, using the above adjustment method will reduce the initial speed, then call the value of the last lookahead as the lookahead speed this time.

[0061] More specifically, step S71 is specifically:

[0062] Set the existence of the to-be-lengthened acceleration-constant speed-deceleration speed curve K0, and v s ≤v e , denote v s as the start point speed, v e as the end point speed, and set the planning limits B1, B2, B3, B4, establish the speed planning curve K1, K2, K3, K4, and denote the synchronization time as T F ; the T-type speed time synchronization method is specifically:

[0063] The time limit T B1 corresponding to B1 is:

[0064]

[0065] In the formula, S represents the length of the corresponding segment;

[0066] The time limit T B2 corresponding to B2 is:

[0067]

[0068] The time limit T B3 corresponding to B3 is:

[0069]

[0070] The time limit T B4 corresponding to B4 is:

[0071]

[0072] where v e_down represents the final speed of the descent;

[0073] If the synchronization time satisfies T F ≤ T B1 , the constant speed segment is reduced to synchronize K0 with speed curve K1, i.e. planning in the manner of acceleration-constant speed-deceleration; where v m is reduced to v m1 , the acceleration, constant speed, and deceleration segment times are T K1_1 , T K1_2 , and T K1_3 , respectively, and the formula is expressed as:

[0074]

[0075] If the synchronization time satisfies T B1 ≤ T F < T B2 , the constant speed segment is synchronized with speed curve K2, i.e. planning in the manner of constant speed-acceleration-constant speed; the corresponding times of the segments are T K2_1 , T K2_2 , and T K2_3 , respectively, and the formula is expressed as:

[0076]

[0077] If the synchronization time satisfies T B2 ≤ T F < T B3 , the constant speed segment is synchronized with speed curve K3, i.e. planning in the manner of constant speed-acceleration; where v e is reduced to v e-K3 , the corresponding times of the segments are T K3_1 , T K3_2 , and the formula is expressed as:

[0078]

[0079] If the synchronization time satisfies T B3 ≤ T F < T B4 , the final speed is reduced to synchronize K0 with speed curve K4, i.e. planning in the manner of deceleration-constant speed. Where v e is reduced to v e-K4 , the corresponding times of the segments are T K4_1 , T K4_2 , and the formula is expressed as:

[0080]

[0081] Further, step S8 specifically includes:

[0082] S81, for the non-last time, output the data of other segments in the look-ahead segment except the last segment of circular arc and two segments of remaining straight lines, save the data of the last segment of circular arc and two segments of straight lines, and then start the loop execution to perform the next segment look-ahead;

[0083] S82, for the last time, output all the data;

[0084] S83, the output data is real-time planned machining trajectory according to the adjustment speed.

[0085] Based on the above technical solutions, the present application has the following beneficial effects:

[0086] 1, the present application proposes a point cloud trajectory planning method suitable for curved surface components, constructs a robot polishing machining system, and meets the polishing machining demand of numerous mold curved surface components.

[0087] 2, the present application proposes a point cloud acquisition posture optimization method, adopts and unifies the constraints of robot joint angle and operability, takes the posture optimization of curved surface machining process as the target, establishes a nonlinear target function of optimal robot machining posture, and adopts a genetic algorithm to obtain the optimal machining posture.

[0088] 3, the present application proposes a pose arc transition model, comprehensively considers the constraints of profile error, camber error, speed, acceleration, angular velocity, angular acceleration, and pose change amount, and provides pose synchronous initialization data.

[0089] 4, the present application proposes a multi-boundary analytical pose synchronization method, which not only considers the speed and acceleration of position, but also considers the speed and acceleration of posture change, realizes pose synchronization in an analytical synchronization manner, and avoids posture mutation.

[0090] 5, the present application proposes a T-shaped speed and pose synchronization method, establishes a time lengthening strategy in different situations, classifies the initial pose synchronization method and the changed pose synchronization method according to the end speed change, avoids the change of initial speed by reducing the constant speed or end speed of the segment to be lengthened, and improves the machining efficiency.

[0091] 6, the present application proposes a nested pose synchronization look-ahead algorithm, strictly guarantees the current segment pose synchronization, and avoids the influence of the current pose look-ahead on the result of the last pose look-ahead. BRIEF DESCRIPTION OF DRAWINGS

[0092] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0093] Figure 1 Overall flowchart of the method proposed in the present application;

[0094] Figure 2 Robot polishing machining system;

[0095] Figure 3 Acquired local machining pose;

[0096] Figure 4 Optimized local machining pose;

[0097] Figure 5 Flowchart of pose synchronization look-ahead planning algorithm in the method proposed in the present application;

[0098] Figure 6 Pose transition model diagram in the method proposed in the present application;

[0099] Figure 7 Schematic diagram of pose synchronization mode in the method proposed in the present application;

[0100] Figure 8 Position diagram of the comparative method;

[0101] Figure 9 Attitude diagram of the comparative method;

[0102] Figure 10 Speed diagram of the comparative method planning;

[0103] Figure 11 Angular velocity diagram of the comparative method planning;

[0104] Figure 12 Position diagram of the method proposed in the present application;

[0105] Figure 13 Attitude diagram of the method proposed in the present application;

[0106] Figure 14 Speed diagram of the method proposed in the present application planning;

[0107] Figure 15 Angular velocity diagram of the method proposed in the present application planning.

[0108] The reference signs in the figures are: 1-industrial robot, 2-constant force flange, 3- eccentric polisher, 4-binocular vision, 5-curved composite component, 6- placement table. DETAILED DESCRIPTION

[0109] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0110] The steps in the present application are arranged by using labels, but are not used to limit the sequence of the steps, unless the sequence of the steps is explicitly described or the execution of a certain step needs other steps as a basis, otherwise the relative sequence of the steps can be adjusted. It can be understood that the term "and / or" used herein relates to and covers any and all possible combinations of one or more of the associated listed items.

[0111] As shown in Figure 1 The present application proposes a point cloud trajectory planning method for a robot polishing system, which specifically includes the following steps:

[0112] S1, establish an industrial robot polishing processing system hardware configuration, including an industrial robot, a constant force flange, an eccentric polishing machine, a binocular vision measurement device, a curved surface composite component and a workbench;

[0113] As shown in Figure 2 The constant force flange is fixedly connected with the eccentric polishing machine and is installed at the end of the robot, is responsible for polishing processing, and controls the processing force to be stable at a constant value; the curved surface composite component is placed on the workbench; the binocular vision measurement device is placed on the ground at a certain distance from the processing area, so as to ensure that the curved surface composite component, i.e. the workpiece to be processed, is in an optimal position in the field of view.

[0114] S2, establish a coordinate system by using the binocular vision measurement device, and obtain three-dimensional point cloud information of the workpiece to be processed by using a ball sweep in the binocular vision measurement device;

[0115] More specifically, in step S2, the robot base coordinate system, the workpiece coordinate system, the wrist coordinate system and the tool coordinate system are established by using the binocular vision measurement device; the point cloud of the workpiece to be processed relative to the workpiece coordinate system is obtained by using the ball sweep in the binocular vision measurement device; and the three-dimensional point cloud information of the workpiece to be processed under the robot base coordinate system is obtained according to the conversion relationship of the workpiece coordinate system relative to the robot base coordinate system.

[0116] S3, perform filtering sampling preprocessing on the three-dimensional point cloud information obtained in step S2, and obtain the robot processing position and attitude by using a point cloud algorithm processing method;

[0117] As a preferred embodiment, step S3 specifically includes:

[0118] S31, remove noise data by statistical filtering; statistics of the neighborhood of each point is performed to obtain a result of approximate Gaussian distribution, and the average distance d and the standard deviation of each point to all adjacent points are calculated σ , a standard deviation coefficient std is determined, and points with an average distance outside the standard range D=d+stdxσ are removed, i.e., points that are "dispersed" compared with the surrounding adjacent points are removed;

[0119] S32, obtain simplified point cloud data by using voxel downsampling method, determine rows, columns and layers according to the maximum and minimum values of the point cloud and the grid size, place each point cloud data in the corresponding grid according to the coordinates, and calculate the centroid of the non-empty grid to replace all points in the voxel;

[0120] S33, use two planes with a distance d to intercept the point cloud layer, project the point cloud layer to the middle plane of the two planes to obtain initial path points, and use NURBS curve fitting to fit the path points to obtain discrete machining positions with equal step length;

[0121] S34, by using a point cloud normal vector algorithm, a plane fitted by point clouds in the radius R sphere range of the machining position obtained in step S33 is obtained, any key point on one side of the curved surface is selected to obtain a normal vector of the fitted plane towards the key point as the normal vector of the machining position;

[0122] The k-th NURBS curve rational expression given in this embodiment is as follows:

[0123]

[0124] wherein ω i represents a control factor; d i represents a control vertex; N i,k (u) represents a k-th normal B-spline basis function determined according to the de Boor-Cox recursive formula.

[0125] S35, the normal vector obtained in step S34 is taken as the z-axis, and the x and y axes are arbitrarily set to satisfy the right-hand coordinate system principle, the Euler angle of the xyz coordinate system relative to the robot base coordinate system is calculated, the Euler angle and the coordinates of the machining position obtained in step S33 are taken as the machining pose, and the robot base coordinate system is established by the binocular vision measurement device.

[0126] S4, according to the machining pose obtained in step S3, the robot machining pose is optimized by using the robot machining pose constraint condition to obtain the final robot pose optimization result;

[0127] As a preferred embodiment, step S4 specifically includes:

[0128] S41, according to the robot inverse kinematics, the joint angle corresponding to different robot end poses is calculated, the joint range is obtained according to the robot technical parameters, and the ratio of the position of the joint to the median value of the joint range is taken as the ratio of the joint motion range, which is taken as the robot joint index R θ As follows:

[0129]

[0130] Wherein, n Indicates the number of robot joints, θ imin Indicates the minimum limit of joint i, 1≤i≤6, θ imax Indicates the maximum limit of joint i, θ imid Indicates the intermediate limit of joint i, and θ i Indicates the angle of each joint, and θ imin ≤θ i ≤θ imax ;

[0131] S42, the operability is a comprehensive measure of the motion ability of the robot in each direction at a certain pose. The reciprocal of the operability is taken as the dexterity index R of the robot ω , the formula is:

[0132]

[0133] Wherein, The operability J(θ) is the Jacobian matrix;

[0134] S43, on the basis of steps S41 and S42, the dimensionless variable of the robot joint index and the robot dexterity index is obtained, the change angle of the robot end pose corresponding to the machining path point is taken as the variable, the nonlinear objective function for obtaining the optimal value of the robot machining pose is established, the genetic algorithm is selected to optimize and solve the target, and the optimal pose change angle is obtained. The pose obtained is used as the final robot machining pose.

[0135] S5, according to the pose result obtained in step S4, select N pose look-ahead trajectory segments, N≥3, and initialize parameter setting according to the pose transition model and speed constraint;

[0136] As a preferred embodiment, step S5 in the embodiment specifically includes:

[0137] S51, position transition initialization; for the first time, the initialization of the look-ahead, get the maximum error under the radius of the arc, get a half track segment as the radius of the arc transition, the smaller value of the above two radius as the value of the initialization of the arc radius, the first segment of the look-ahead initial speed and the last segment of the end point speed are set to 0; the arc segment speed constraint is set according to the acceleration, normal acceleration, maximum speed comprehensive limit; the speed and acceleration constraints of the straight line segment are limited according to the maximum speed and maximum acceleration respectively; the connection point constraint condition of the straight line segment and the arc segment is according to the speed and acceleration constraints of the arc segment.

[0138] In this embodiment, as shown in Figure 6 P n1 , P n2 , P n3 , P n4 , P n5 , P n6 , P n7 are the end points of the position micro-segment, P0 is the end point of the position line segment P n2 corresponding to the center point of the transition arc segment, P1, P2 are the tangent points of the position transition arc segment and the position straight line segment, P3, P4 are the position points of adjacent two times interpolation, P5 is the intersection point of P0P n2 and the arc, P6 is the intersection point of P3P4 and P0P n2 , P7 is the intersection point of P1P2 and P0P n2 , L1, L2, L3, L4, L5, L6 are the lengths corresponding to the position segments P n1 P n2 , P n2 P n3 , P n3 P n4 , P n4 P n5 , P n5 P n6 , P n6 P n7 , Z n1 , Z n2 , Z n3 , Z n4 , Z n5 , Z n6 , Z n7 are the end points of the attitude micro-segment, Z0 is the end point of the attitude line segment Z n2 corresponding to the center point of the transition arc segment, Z1, Z2 are the tangent points of the attitude transition arc segment and the attitude straight line segment, Z3, Z4 are the attitude points of adjacent two times interpolation, Z5 is the intersection point of Z0Z n2 and the arc, Z6 is the intersection point of Z3Z4 and Z0Z n2 , Z7 is the intersection point of Z1Z2 and Z0Z n2The intersection of is the intersection of and posture, A1, A2, A1, A1, A1, A1 represent posture segment Z n1 Z n2 , Z n2 Z n3 , Z n3 Z n4 , Z n4 Z n5 , Z n5 Z n6 , Z n6 Z n7 The corresponding length.

[0139] For the position micro segment, the maximum speed of the straight line segment and the arc segment is v max , the maximum angular velocity is w max , the maximum acceleration is a max , maximum angular acceleration α max , set the maximum normal acceleration equal to the maximum acceleration. n2 Corresponding to the transition arc segment, set P3P4 perpendicular to P0P n2 ; Set the bow height error generated at the highest speed to e ch , that is, the contour error generated by interpolation at the highest speed set by P5P6 is e co , that is, P n2 P6; Set line segment P n1 P n2 With line segment P n2 P n3 The angle between them is θ, that is, ∠P n1 P n2 P n3 .

[0140] Depend on Figure 6 Position arc transition in the pose arc transition model, where the arc error radius r err The formula is expressed as:

[0141] r err / (e co -e ch +r err ) = sin(θ / 2);

[0142] r err =sin(θ / 2)×(e co -e ch ) / (1-sin(θ / 2));

[0143] When the transition arc radius is too long, select half of the smaller segment of the adjacent line segment as the transition arc constraint to meet the transition length requirement of the straight line segment and determine the arc radius r len for:

[0144] r len = min(L1, L2) / (2 tan(θ / 2));

[0145] According to the circular arc error radius and the circular arc radius, a preset transition circular arc radius r n = min(r err , r len );

[0146] According to the circular arc normal acceleration and the preset transition circular arc radius, the allowable velocity of the circular arc segment is obtained as:

[0147]

[0148] Further, the velocity constraint of the circular arc segment is v n = min(v rmax , v max ), and the circular arc radius and the velocity constraint of the other position endpoint corresponding circular arc segment can be obtained in the same way;

[0149] For the pose micro-line segment, the calculation is the same as above.

[0150] S52, for the initialization of non-first look-ahead, the look-ahead starting point velocity is set according to the final velocity output by the last look-ahead, and the preset mode of the remaining variables is the same as the first look-ahead in step S51;

[0151] S53, on the basis of steps S51 and S52, the boundary velocity determination method is formulated according to the boundary velocity of the straight line; in the acceleration process, the end velocity constraint is reduced to the maximum speed that can be accelerated by the starting speed of the straight line segment; in the deceleration process, the starting point velocity constraint is reduced to the maximum speed that can be accelerated in the opposite direction by the end velocity of the straight line segment, and the parameter setting of the position transition initialization is updated according to the velocity constraint;

[0152] S54, in the same way, the pose transition initialization is performed according to the process described in steps S51-S53.

[0153] S6, the planning time of the straight line segment and the circular arc segment of the robot position and pose is obtained by the T-type velocity interpolation method, and the pose synchronization judgment is performed to determine the information of the segment to be synchronized and lengthened;

[0154] As a preferred embodiment, step S6 is specifically:

[0155] The planning time of the position and pose of the straight line segment and the circular arc segment is obtained by the T-type velocity interpolation, the pose planning time is compared and analyzed, it is judged whether the shorter time corresponds to a position segment or a pose segment, and the type corresponding to the time lengthening segment is determined, that is:

[0156] In the process of posture synchronization in each trajectory segment, the position planning time T is obtained according to the T-type speed planning. v and posture planning time T w , the following three situations may occur:

[0157] When T v =T w ,At this time, the position and attitude planning time are consistent, and no posture synchronization adjustment is performed;

[0158] When T v >T w ,At this time, the position planning time is greater than the attitude planning time, and the attitude planning time is synchronously extended;

[0159] When T v <T w At this time, the position planning time is less than the posture planning time, and the position planning time is synchronously extended.

[0160] S7, based on the posture synchronization judgment result of step S6, adjusting the posture synchronization of the arc segment and the straight line segment respectively by a speed synchronization method;

[0161] As a preferred embodiment, step S7 specifically includes:

[0162] S71. Determine a T-type speed-time synchronization method based on the posture synchronization requirements; obtain different posture synchronization methods by setting time limits; set the initial posture synchronization method when the terminal speed remains unchanged, and set the modified posture synchronization method when the terminal speed changes;

[0163] like Figure 7 As shown, the T-type speed time synchronization method in this embodiment is specifically as follows:

[0164] Assume that there is a speed curve K0 of acceleration-constant speed-deceleration to be stretched, and v s ≤v e , remember v s Indicates the starting point speed, v e Indicates the terminal speed, sets the planning boundaries B1, B2, B3, B4, establishes the speed planning curves K1, K2, K3, K4, and records the synchronization time as T F The T-type speed time synchronization method is specifically as follows:

[0165] The time limit T corresponding to B1 B1 for:

[0166]

[0167] Where S represents the length of the corresponding segment;

[0168] The time limit T corresponding to B2B2 is:

[0169]

[0170] B3 corresponding time limit T B3 is:

[0171]

[0172] B4 corresponding time limit T B4 is:

[0173]

[0174] In the formula v e_down indicates the final speed of the descent;

[0175] If the synchronization time satisfies T F <T B1 , the constant speed segment is reduced to synchronize K0 with speed curve K1, that is, planning in the manner of acceleration-constant speed-deceleration; wherein v m is reduced to v m1 , the acceleration, constant speed, and deceleration segment times are T K1_1 , T K1_2 , and T K1_3 , respectively, and the formula is expressed as:

[0176]

[0177] If the synchronization time satisfies T B1 ≤T F <T B2 , K0 is synchronized with speed curve K2, that is, planning in the manner of constant speed-acceleration-constant speed; the corresponding times of the segments are T K2_1 , T K2_2 , and T K2_3 , and the formula is expressed as:

[0178]

[0179] If the synchronization time satisfies T B2 ≤T F <T B3 , K0 is synchronized with speed curve K3, that is, planning in the manner of constant speed-acceleration; wherein v e is reduced to v e-K3 , the corresponding times of the segments are T K3_1 , T K3_2 , and the formula is expressed as:

[0180]

[0181] If the synchronization time satisfies T B3 ≤TF <T B4 , the end speed is reduced to synchronize K0 with the speed curve K4, that is, planning in the mode of deceleration-constant speed. Wherein v e is reduced to v e-K4 , the corresponding time of each segment is T K4_1 , T K4_2 , and the formula is expressed as:

[0182]

[0183] S72, adjustment is made for all pose circular arc segments, taking the maximum speed v halfS that can be reached by moving half of the circular arc path as the speed limit of the start and end of the circular arc, and obtaining the speed limit of the start and end of the circular arc as v = min(v n , v halfS ), wherein v n is the speed constraint of the circular arc segment, so as to ensure that the start and end speed of the position and attitude circular arc segment meets the pose synchronization requirement no matter how the speed is reduced, and planning is made according to the initial pose synchronization method described in step S71;

[0184] S73, for pose synchronization of a straight line segment, for a time period that needs to be lengthened, first planning is made by the initial pose synchronization method; when the initial pose synchronization method does not meet the synchronization time requirement, the changed pose synchronization method is used for planning; if the synchronization time requirement is still not met, then speed adjustment is made according to specific conditions, that is:

[0185] If the current planning straight line segment is not the first straight line in the look-ahead segment, then the speed of the straight line segment is adjusted, taking the maximum speed as the initial and final speed of the two ends of the straight line, which is obtained by accelerating from 0 to the maximum speed along half of the straight line segment; if the straight line segment is the first straight line in the look-ahead segment at this time, then the initial speed will be reduced by using the above adjustment method, and the value of the last look-ahead is called as the look-ahead speed this time.

[0186] S8, whether it is the last time of pose synchronization look-ahead is judged, and different data output and storage decisions are made. The output data is real-time planning machining trajectory according to the adjusted speed.

[0187] As a preferred embodiment, step S8 specifically includes:

[0188] S81, for non-last look-ahead, outputting other data in the look-ahead segment except the last circular arc and the two remaining straight lines, and saving the data of the last circular arc and the two straight lines, and then starting to loop and execute the next look-ahead;

[0189] S82, for the last look-ahead, outputting all data;

[0190] S83, real-time planning machining trajectory according to the output data.

[0191] In the embodiment, the method can also be summarized as a pose synchronization look-ahead planning algorithm process as shown in the following figure. Figure 5

[0192] The following gives an experimental case to verify the effect of the method proposed in the application:

[0193] Verification 1: Select a part of the point cloud as a simulated polishing area, and use the trajectory obtained by the point cloud slicing algorithm and the normal vector fitting algorithm. There are many problems such as position point redundancy and complexity, and inconsistent normal vectors, as shown in the following figure: Figure 3 After path fitting, normal vector unification, and attitude optimization, the trajectory is smoother and more concise, as shown in the following figure: Figure 4

[0194] Verification 2: The pose synchronization look-ahead algorithm is as shown in the following table 1, and the specific processing parameters are as follows: maximum speed 10 mm / s, maximum acceleration 100 mm / s 2 , maximum profile error 0.05 mm, maximum camber error 0.01 mm; maximum angular velocity 10 rad / s, maximum angular acceleration 100 rad / s 2 , maximum angular profile error 0.05 rad, maximum angular camber error 0.01 rad. Figures 8-11 is the processing result of the comparative method, Figures 12-15 is the processing result of the method proposed in the application. It can be seen that the planned path and attitude of the application are smoother, and the planned speed and angular velocity are more optimal. For the same path, the comparative method takes 1936 ms, and the method of the application takes 1678 ms, with an efficiency improvement of 13.33%.

[0195] Table 1 Point data of the pose to be planned

[0196]

[0197] In summary, the application obtains and optimizes the processing pose according to the live point cloud, realizes pose synchronization look-ahead planning, solves the error problem of the generated trajectory caused by the inability to position the curved surface composite component, avoids attitude mutation caused by small path-large attitude change, meets the curved surface polishing processing demand, and improves the processing efficiency.

[0198] ​​It is to be understood that the application is not limited to the details of the foregoing exemplary embodiments and that the present application can be carried out in other specific forms without departing from the spirit or essential characteristics thereof. Hence, any exemplary embodiment is to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims shall be construed as limiting the scope of the claims to the features

[0199] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and those skilled in the art should understand the description as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A point cloud trajectory planning method for a robotic polishing system, characterized in that: include: S1. Establish the hardware configuration of the industrial robot grinding system, including an industrial robot, a constant force flange, an eccentric grinder, a binocular vision measurement device, a curved composite component, and a storage table. The constant force flange is fixedly connected to the eccentric grinder and installed at the end of the robot, responsible for grinding and controlling the processing force to be stable at a constant value. The curved composite component is placed on the storage table. The binocular vision measurement device is placed on the ground at a certain distance from the processing area to ensure that the curved composite component, i.e., the component to be processed, is in a better position in the field of view. S2. Use a binocular vision measuring device to establish a coordinate system, and use the spherical scanner in the binocular vision measuring device to obtain the three-dimensional point cloud information corresponding to the component to be processed; S3, performing filtering sampling preprocessing on the three-dimensional point cloud information obtained in step S2, and obtaining the robot processing position and posture through a point cloud algorithm processing method; S4. Based on the processing posture obtained in step S3, the robot processing posture constraint conditions are used to optimize the robot processing posture to obtain the final robot posture optimization result; S5. Based on the posture result obtained in step S4, select N posture forward trajectory segments, N ≥ 3, and perform initialization parameter settings based on the posture transition model and velocity constraints; S6. Obtain the planning time of the straight and circular segments of the robot's position and posture through the T-type velocity interpolation method, and perform posture synchronization judgment to determine the information of the segment to be synchronized and stretched; S7, based on the posture synchronization judgment result of step S6, adjusting the posture synchronization of the arc segment and the straight line segment respectively by a speed synchronization method; S8, and determine whether the last posture is synchronized and forward-looking, and make different data output and storage decisions; the output data plans the processing trajectory in real time according to the adjustment speed.

2. A point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S2 is specifically as follows: Use binocular vision measurement equipment to establish the robot base coordinate system, workpiece coordinate system, wrist coordinate system, and tool coordinate system; use the spherical scanner in the binocular vision measurement equipment to obtain the point cloud of the component to be processed relative to the workpiece coordinate system; then, based on the conversion relationship between the workpiece coordinate system and the robot base coordinate system, obtain the three-dimensional point cloud information of the component to be processed under the robot base coordinate system.

3. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S3 specifically includes: S31. Use statistical filtering to remove noise data; perform statistics on the neighborhood of each point to obtain a result of approximate Gaussian distribution, and calculate the average distance d and standard deviation of each point to all nearby points. σ , determine the standard deviation coefficient std, and remove points whose average distance is outside the standard range D = d + std × σ, that is, remove points that are relatively "scattered" around the neighboring points; S32. Use voxel downsampling to obtain simplified point cloud data. Determine rows, columns, and layers based on the maximum and minimum values ​​of the point cloud and the grid size. Place each point cloud data point into the corresponding grid according to its coordinates. Calculate the centroid of the non-empty grid to replace all points in the voxel. S33, intercepting a point cloud layer using two planes separated by a distance d, projecting the point cloud layer onto a plane intermediate the two planes to obtain initial path points; fitting the path points using a NURBS curve to obtain discrete processing positions with equidistant step sizes; S34. Using a point cloud normal vector algorithm, find a plane that fits the point cloud within the sphere of radius R of the processing position obtained in step S33. Select any key point on one side of the surface and obtain the normal vector of the fitting plane toward the key point as the normal vector of the processing position. S35. Use the normal vector obtained in step S34 as the z-axis, and set the x and y axes arbitrarily while satisfying the xyz right-hand coordinate system principle to calculate the Euler angle of this xyz coordinate system relative to the robot base coordinate system; use the Euler angle and the coordinates of the processing position obtained in S33 as the processing posture; the robot base coordinate system is established by a binocular vision measurement device.

4. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S4 specifically includes: S41. Calculate the joint angles corresponding to different robot terminal positions based on the robot inverse kinematics, obtain the joint range based on the robot technical parameters, and take the ratio of the joint position to the median of the joint range to the joint motion range as the robot joint index R. θ , as follows: in, n represents the number of robot joints, θ imin Indicates the minimum limit of joint i, 1≤i≤6, θ imax Indicates the maximum limit of joint i, θ imid Indicates that joint i corresponds to the middle limit of the joint, and θ i represents the angle of each joint, and θ imin ≤θ i ≤θ imax ; S42. Use maneuverability to comprehensively measure the robot's ability to move in all directions under a certain posture. Take the reciprocal of maneuverability as the robot's dexterity index R. ω , the formula is: in, is the operability, J(θ) is the Jacobian matrix; S43. On the basis of step S41 and step S42, dimensionless variables of robot joint index and robot dexterity index are obtained, and the robot end posture change angle corresponding to the processing path point is used as a variable to establish a nonlinear objective function for obtaining the optimal value of the robot processing posture. A genetic algorithm is used to optimize and solve the target to obtain the optimal posture change angle; the obtained posture is used as the final robot processing posture.

5. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S5 specifically includes: S51. Perform position transition initialization. For the first look-ahead initialization, obtain the arc radius under the maximum error, obtain half of the trajectory segment as the arc radius of the arc transition, use the smaller of the two radii as the initial value of the arc radius, set the initial velocity of the first look-ahead segment and the terminal velocity of the last segment to 0; set the arc segment velocity constraint according to the comprehensive restrictions of acceleration, normal acceleration, and maximum velocity; set the velocity and acceleration constraints of the straight segment according to the maximum velocity and maximum acceleration restrictions respectively; set the connection point constraint of the straight segment and the arc segment according to the arc segment velocity and acceleration constraints; S52: For initialization other than the first look-ahead, the look-ahead starting speed is set according to the final speed output by the previous look-ahead, and the preset method of the remaining variables is the same as the first look-ahead setting in step S51; S53. Based on steps S51 and S52, determine whether the boundary speeds at both ends of the line are acceleration or deceleration types, and formulate a boundary speed determination method; during acceleration, the end speed constraint is reduced to the maximum speed to which the starting speed of the line segment can be accelerated; during deceleration, the starting speed constraint is reduced to the maximum speed to which the end speed of the line segment can be accelerated in the reverse direction, and use this speed constraint to update the parameter settings for position transition initialization; S54: Similarly, perform posture transition initialization according to the process described in steps S51-S53.

6. The point cloud trajectory planning method for a robotic polishing system according to claim 5, characterized in that: Step S51 is specifically as follows: Note P n1 、P n2 、P n3 、P n4 、P n5 、P n6 、P n7 is the endpoint of the position micro segment, P0 is the endpoint of the position segment P n2 Corresponding to the center point of the transition arc segment, P1 and P2 are the tangent points of the position transition arc segment and the position straight line segment, P3 and P4 are the position points of two adjacent interpolation points, and P5 is P0P n2 The intersection point with the arc, P6 is P3P4 and P0P n2 The intersection of P1P2 and P0P n2 The intersection of L1, L2, L3, L4, L5, and L6 is the position segment P n1 P n2 、P n2 P n3 、P n3 P n4 、P n4 P n5 、P n5 P n6 、P n6 P n7 The corresponding length; for the position micro segment, the maximum speed of the straight line segment and the arc segment is v max , the maximum angular velocity is w max , the maximum acceleration is a max , maximum angular acceleration α max , set the maximum normal acceleration equal to the maximum acceleration; For the position endpoint P n2 Corresponding to the transition arc segment, set P3P4 perpendicular to P0P n2 ; Set the bow height error generated at the highest speed to e ch , namely P5P6; set the contour error generated by interpolation at the highest speed to e co , that is, P n2 P6; Set line segment P n1 P n2 With line segment P n2 P n3 The angle between them is θ, that is, ∠P n1 P n2 P n3 ; The position arc transition in the pose arc transition model, where the arc error radius r err The formula is expressed as: r err / (e co -e ch +r err )=sin(θ / 2); r err =sin(θ / 2)×(e co -e ch ) / (1-sin(θ / 2)); When the transition arc radius is too long, select half of the smaller segment of the adjacent line segment as the transition arc constraint to meet the transition length requirement of the straight line segment and determine the arc radius r len for: r len =min(L1,L2) / (2tan(θ / 2)); According to the arc error radius and arc radius, the preset transition arc radius r is obtained n =min(r err ,r len ); According to the normal acceleration of the arc and the preset transition arc radius, the allowable speed of the arc segment is: Then the velocity constraint of the arc segment is obtained as v n =min(v rmax ,v max ), the arc radius and speed constraints of the arc segments corresponding to other position endpoints can be obtained in the same way; The same calculation is performed for the posture micro-segments.

7. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S6 is specifically as follows: Use T-type velocity interpolation to obtain the planning time of the position and posture of the straight and circular segments. Compare and analyze the posture planning time to determine whether the shorter time corresponds to the position segment or the posture segment, and determine the type of the time-extended segment, that is: In the process of posture synchronization in each trajectory segment, the position planning time T is obtained according to the T-type speed planning. v and posture planning time T w , the following three situations may occur: When T v =T w ,At this time, the position and attitude planning time are consistent, and no posture synchronization adjustment is performed; When T v >T w ,At this time, the position planning time is greater than the attitude planning time, and the attitude planning time is synchronously extended; When T v <T w At this time, the position planning time is less than the posture planning time, and the position planning time is synchronously extended.

8. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S7 is specifically as follows: S71. Determine a T-type speed-time synchronization method based on the posture synchronization requirements; obtain different posture synchronization methods by setting time limits; set the initial posture synchronization method when the terminal speed remains unchanged, and set the modified posture synchronization method when the terminal speed changes; S72, adjust all the arc segments of the posture, and calculate the maximum speed v that can be achieved by moving half the arc path from 0. halfS As the arc start and end speed limit, the arc start and end speed limit is obtained as v=min(v n ,v halfS ), where v n The arc segment speed constraint is used to ensure that the starting and ending speeds of the arc segment of the position and attitude meet the posture synchronization requirements no matter how they decrease. The initial posture synchronization method described in step S71 is used for planning. S73. For the posture synchronization of the straight segment, for the time period that needs to be extended, first plan using the initial posture synchronization method; if the initial posture synchronization method does not meet the synchronization time requirement, plan using the modified posture synchronization method; if the synchronization time requirement is still not met, adjust the speed according to the specific situation, that is: If the currently planned straight line segment is not the first straight line segment in the forward-looking segment, the speed of the straight line segment is adjusted, and the speed is accelerated from 0 to the maximum speed halfway along the straight line segment as the initial and final speeds at both ends of the current straight line; if the straight line segment is the first straight line segment in the forward-looking segment, the above adjustment method will reduce the initial speed, and the value of the previous forward-looking segment is called as the current forward-looking speed.

9. The point cloud trajectory planning method for a robotic polishing system according to claim 8, characterized in that: Step S71 specifically includes: Assume that there is a speed curve K0 of acceleration-constant speed-deceleration to be stretched, and v s ≤v e , remember v s Indicates the starting point speed, v e Indicates the terminal speed, sets the planning boundaries B1, B2, B3, B4, establishes the speed planning curves K1, K2, K3, K4, and records the synchronization time as T F The T-type speed time synchronization method is specifically as follows: The time limit T corresponding to B1 B1 for: Where S represents the length of the corresponding segment; The time limit T corresponding to B2 B2 for: The time limit T corresponding to B3 B3 for: The time limit T corresponding to B4 B4 for: Where v e_down Indicates the final velocity of descent; If the synchronization time satisfies T F <T B1 , then reduce the speed of the constant speed section and synchronize K0 with the speed curve K1, that is, plan in the manner of acceleration-constant speed-deceleration; where v m Degraded to v m1 The acceleration, constant speed and deceleration time are T K1_1 、T K1_2 、T K1_3 , the formula is: If the synchronization time satisfies T B1 ≤T F <T B2 , then the speed curve K2 is synchronized with K0, that is, the planning is carried out in the manner of constant speed-acceleration-constant speed; the corresponding time of each section is T K2_1 、T K2_2 、T K2_3 , the formula is: If the synchronization time satisfies T B2 ≤T F <T B3 , then K0 is synchronized with the speed curve K3, that is, planning is performed in a constant speed-acceleration manner; wherein, v e Degraded to v e-K3 , the time corresponding to each segment is T K3_1 、T K3_2 , the formula is: If the synchronization time satisfies T B3 ≤T F <T B4 , reduce the terminal speed and synchronize K0 with the speed curve K4, that is, plan in the manner of deceleration-constant speed; where v e Degraded to v e-K4 , the time corresponding to each segment is T K4_1 、T K4_2 , the formula is:

10. The point cloud trajectory planning method for a robotic polishing system according to claim 1, characterized in that: Step S8 specifically includes: S81. For non-final look-ahead operations, output the remaining data in the look-ahead segment except for the last arc segment and the two remaining straight lines, save the data of the last arc segment and the two straight lines, and then start a loop to execute the next look-ahead segment. S82. For the last look-ahead, all data are output; S83, planning the processing trajectory in real time based on the output data and the adjusted speed.

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