A workpiece detection method, device, equipment and medium

Abstract

A workpiece detection method, device, equipment and medium, including constructing a corresponding workpiece motion chain based on the workpiece to be detected, constructing a corresponding sensor motion chain based on the sensor rotation axis and the laser line scanning sensor, constructing a transfer function according to the workpiece motion chain and the sensor motion chain, and constructing a kinematic model according to the transfer function and the motion parameters corresponding to the transfer function; establishing a first expression corresponding to the measurement point on the workpiece to be detected based on the workpiece motion chain, and establishing a second expression corresponding to the measurement point based on the sensor motion chain; performing a simultaneous solution according to the first expression, the second expression, the kinematic model and the motion screw theory to obtain the expansion formula of the measurement point, and performing a calibration process on the model parameters in the expansion formula to obtain the final workpiece measurement value. When scanning and detecting workpieces with complex shapes, the accuracy and efficiency of workpiece scanning are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser measurement, and particularly relates to a workpiece detection method, device, equipment and medium. Background Art

[0002] In the field of industrial inspection, a laser beam of a laser line scanning sensor is usually used to linearly scan the surface of a workpiece to be measured, so as to obtain information such as the shape, size and position of an object. Due to the influence of angle factors, when measuring a workpiece with a complex shape, it is necessary to change the angle of the workpiece or the sensor to obtain the point cloud data of the target area. If you want to completely scan a workpiece with a complex shape, it is necessary to splice the point cloud data of different areas obtained into a whole. The traditional method is implemented based on point cloud matching algorithms. For example, point cloud splicing algorithms based on set features, point cloud splicing algorithms based on adjacent search, point cloud splicing methods based on ICP algorithms, etc. The splicing accuracy of the foregoing algorithms depends on the quality of the point cloud data and the feature extraction algorithm, and it is required that there must be an overlapping area between two pieces of point cloud. These two factors will affect the splicing accuracy and splicing correct rate of the point cloud, thereby affecting the result of workpiece detection. Summary of the Invention

[0003] The main technical problem to be solved by the present invention is that when scanning and detecting a workpiece with a complex shape, only by adjusting the angle can different fragment point cloud data corresponding to the workpiece be obtained and spliced to obtain a complete workpiece scanning result. Therefore, the accuracy and efficiency of workpiece scanning are not high.

[0004] According to a first aspect, in one embodiment, a workpiece detection method is provided, which is applied to a multi-axis measurement system. The multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis and a laser line scanning sensor; the method includes:

[0005] Constructing a corresponding workpiece motion chain based on the workpiece to be detected. During the process of constructing the workpiece motion chain, a workpiece coordinate system corresponding to the workpiece rotation axis is constructed;

[0006] Constructing a corresponding sensor motion chain based on the sensor rotation axis and the laser line scanning sensor. During the process of constructing the sensor motion chain, a sensor coordinate system corresponding to the laser line scanning sensor is constructed;

[0007] Constructing a transfer function according to the workpiece motion chain and the sensor motion chain, and constructing a kinematic model according to the transfer function and the motion parameters corresponding to the transfer function;

[0008] Establishing a first expression corresponding to a measurement point on the workpiece to be detected based on the workpiece motion chain, and establishing a second expression corresponding to the measurement point based on the sensor motion chain; the measurement point includes the measurement point in the sensor coordinate system;

[0009] Simultaneous solution is performed according to the first expression, the second expression, the kinematic model and the kinematic screw theory to obtain the expansion formula of the measurement point, and calibration processing is performed on the model parameters in the expansion formula to obtain the final workpiece measurement value; the final workpiece measurement value includes the measurement value in the workpiece coordinate system.

[0010] In some embodiments, the multi-axis measurement system further includes linear axes, the linear axes include a horizontal axis, a vertical axis and a vertical axis, a corresponding reference coordinate system is constructed according to the horizontal axis, the vertical axis and the vertical axis, and the workpiece rotation axis is arranged at the intersection of the horizontal axis and the vertical axis in the reference coordinate system, and the sensor rotation axis is arranged perpendicular to the vertical axis in the reference coordinate system; the workpiece to be detected is placed on the workpiece rotation axis, the laser line scanning sensor is arranged on the sensor rotation axis, and the workpiece to be detected is linearly scanned by using the laser line scanning sensor.

[0011] In some embodiments, constructing a corresponding workpiece motion chain based on the workpiece to be detected includes:

[0012] Constructing a reference coordinate system corresponding to the workpiece to be detected; the reference coordinate system includes a coordinate system constructed according to the linear axes;

[0013] Based on the reference coordinate system, the linear axes having a preset motion relationship with the workpiece to be detected, the workpiece rotation axis and the workpiece coordinate system, a workpiece motion chain is established.

[0014] In some embodiments, constructing a corresponding sensor motion chain based on the sensor rotation axis and the laser line scanning sensor includes:

[0015] Constructing a reference coordinate system corresponding to the workpiece to be detected and obtaining the translation amount corresponding to the laser line scanning sensor;

[0016] Based on the reference coordinate system, a preset axis in the linear axes, the sensor rotation axis, the laser line scanning sensor and the translation amount, a sensor motion chain is established.

[0017] In some embodiments, constructing a transfer function according to the workpiece motion chain and the sensor motion chain includes:

[0018] U = {x, y, z, θ B, θ C, s, SL}

[0019] where U represents the transfer function, x represents the offset distance corresponding to the X axis in the linear axes, y represents the offset distance corresponding to the Y axis in the linear axes, z represents the offset distance corresponding to the Z axis in the linear axes, θB Represents the offset angle corresponding to the rotation axis of the sensor, θ c Represents the offset angle corresponding to the rotation axis of the workpiece, s represents the reference measurement point corresponding to the laser line scanning sensor, and SL represents the translation amount corresponding to the laser line scanning sensor.

[0020] In some embodiments, establishing the second expression corresponding to the measurement point on the workpiece to be detected based on the sensor kinematic chain includes:

[0021] The second expression is P M = g MZ (MZ)g MB (θ MB )g S (S)g SL (SL)g MS (0)P S

[0022] Wherein, P M Represents the measurement point expressed according to the sensor kinematic chain in the reference coordinate system, g MZ (MZ) represents the transformation matrix from the reference coordinate system to the vertical axis in the linear axis, g MB (θ MB ) represents the transformation matrix from the reference coordinate system to the rotation axis of the sensor, g S (S) represents the transformation matrix corresponding to the laser scanning sensor, g SL (SL) represents the transformation matrix of the translation amount corresponding to the laser line scanning sensor, g MS (0) represents the transformation matrix from the reference coordinate system to the laser line scanning sensor, P S Represents the measurement point in the sensor coordinate system corresponding to the laser line scanning sensor.

[0023] In some embodiments, calibrating the model parameters in the expansion formula to obtain the final workpiece measurement value includes:

[0024] Using a preset non-linear optimization algorithm to optimize the model parameters in the expansion formula to obtain optimized model parameters;

[0025] Substituting the optimized model parameters into the expansion formula of the measurement point to obtain the final workpiece measurement value.

[0026] According to a second aspect, in one embodiment, a workpiece detection device is provided, which is applied in a multi-axis measurement system. The multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis, and a laser line scanning sensor; it includes:

[0027] A workpiece kinematic chain construction module is used to construct a corresponding workpiece kinematic chain based on the workpiece to be detected, wherein a workpiece coordinate system corresponding to the workpiece rotation axis is constructed in the process of constructing the workpiece kinematic chain;

[0028] A sensor kinematic chain construction module, used to construct a corresponding sensor kinematic chain based on the laser line scanning sensor, wherein a sensor coordinate system corresponding to the laser line scanning sensor is constructed in the process of constructing the sensor kinematic chain;

[0029] A kinematic model building module, used to build a transfer function according to the workpiece kinematic chain and the sensor kinematic chain, and to build a kinematic model according to the transfer function and the kinematic parameters corresponding to the transfer function;

[0030] A measuring point calculation module is used to establish a first expression corresponding to the measuring point on the workpiece to be detected based on the workpiece motion chain, and to establish a second expression corresponding to the measuring point based on the sensor motion chain; the measuring point includes the measuring point in the sensor coordinate system, and the first expression, the second expression, the kinematic model and the motion spiral theory are jointly solved to obtain the expansion of the measuring point, and the model parameters in the expansion are calibrated to obtain the final workpiece measurement value; the final workpiece measurement value includes the measurement value in the workpiece coordinate system.

[0031] According to a third aspect, an embodiment provides a workpiece detection device, comprising:

[0032] Memory, used to store programs;

[0033] The processor is used to implement the workpiece detection method by executing the program stored in the memory.

[0034] According to a fourth aspect, an embodiment provides a computer-readable storage medium, characterized in that a program is stored on the medium, and the program can be executed by a processor to implement a workpiece detection method.

[0035] According to the workpiece detection method, device, equipment and medium of the above-mentioned embodiment, since the workpiece motion chain and the sensor motion chain are respectively constructed by the workpiece rotation axis, the sensor rotation axis and the laser line scanning sensor in the multi-axis measurement system, the corresponding motion conditions are described from the motion angle of the workpiece and the angle of the laser line scanning sensor. The transfer function is constructed according to the workpiece motion chain and the sensor motion chain. At the same time, the transfer function and the motion parameters corresponding to the transfer function jointly construct a kinematic model to accurately describe the situation of scanning the workpiece to be detected using the multi-axis measurement system. The measurement point on the workpiece to be detected is used as the reference point, and the first expression and the second expression corresponding to the reference point are constructed from the perspective of the workpiece motion chain and the sensor motion chain, respectively. The above expressions are solved jointly in combination with the kinematic model and the motion spiral theory to obtain the expansion of the measurement point. After calibrating the model parameters in the expansion, the final workpiece measurement value can be obtained. Therefore, the detection result of the workpiece to be detected in the workpiece coordinate system can be directly, comprehensively and accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of the structure of a multi-axis measurement system according to an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the structure of a multi-axis measurement system according to an embodiment;

[0038] Figure 3 A workpiece detection flow chart of an embodiment;

[0039] Figure 4 A workpiece detection flow chart of another embodiment;

[0040] Figure 5 is a schematic diagram of a workpiece kinematic chain of an embodiment;

[0041] Figure 6 A workpiece detection flow chart of an embodiment;

[0042] Figure 7 is a schematic diagram of a sensor kinematic chain according to an embodiment;

[0043] Figure 8 is a schematic diagram of a closed-loop kinematic chain of an embodiment;

[0044] Figure 9 A workpiece detection flow chart of an embodiment;

[0045] Figure 10 The figure is a schematic structural diagram of a workpiece detection device according to an embodiment. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below in conjunction with the specific embodiments and the accompanying drawings. Similar elements in different embodiments are denoted by related similar element numbers. In the following embodiments, many details are described to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0047] In addition, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can also be reordered or adjusted in a manner obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for clearly describing a certain embodiment, and do not mean that they are the necessary sequences, unless it is stated otherwise that a certain sequence must be followed.

[0048] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. And the "connection" and "coupling" mentioned in the present application, unless otherwise specified, both include direct and indirect connection (coupling).

[0049] Please refer to Figure 1 , in an embodiment of the present invention, a workpiece detection method is provided, which is applied in a multi-axis measurement system. The multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis, and a laser line scanning sensor. The workpiece rotation axis is the C axis, the sensor rotation axis is the B axis, and the laser line scanning sensor is S. Among them, the workpiece to be detected is placed on the workpiece rotation axis, the laser line scanning sensor is hung on the sensor rotation axis, and the laser line scanning sensor is used to detect the workpiece to be detected.

[0050] Please refer to Figure 2, in some embodiments, the multi-axis measurement system further includes linear axes, where the linear axes include a horizontal axis, a vertical axis, and a longitudinal axis, that is, the X-axis, the Y-axis, and the Z-axis. A corresponding reference coordinate system is constructed based on the horizontal axis, the vertical axis, and the longitudinal axis. This reference coordinate system is a virtual coordinate system constructed from the perspective of the linear axes for the user to refer to. In the construction of the multi-axis measurement system, the workpiece to be detected is placed on the workpiece rotation axis C-axis, and the workpiece rotation axis C-axis is set at the intersection of the horizontal axis X-axis and the vertical axis Y-axis in the reference coordinate system. Therefore, the X-axis and the Y-axis drive the C-axis to move. The sensor rotation axis B-axis is set perpendicular to the longitudinal axis Z-axis in the reference coordinate system, the laser line scanning sensor S is set on the sensor rotation axis B-axis, and the laser line scanning sensor S is used to linearly scan the workpiece to be detected.

[0051] Please refer to Figure 3 , in some embodiments, the workpiece detection method includes steps S1 to S5, which are specifically described below.

[0052] Step S1: Construct a corresponding workpiece motion chain based on the workpiece to be detected. During the construction of the workpiece motion chain, a workpiece coordinate system corresponding to the workpiece rotation axis is constructed.

[0053] Please refer to Figure 4 , in some embodiments, step S1 constructs a corresponding workpiece motion chain based on the workpiece to be detected, including steps S11 to S12, which are specifically described below.

[0054] Step S11: Construct a reference coordinate system corresponding to the workpiece to be detected; the reference coordinate system includes a coordinate system constructed based on the linear axes.

[0055] In some embodiments, the reference coordinate system includes a virtual coordinate system constructed based on the X-axis, the Y-axis, and the Z-axis, where the X-axis, the Y-axis, and the Z-axis are equivalent to the horizontal axis, the vertical axis, and the longitudinal axis in the linear axes.

[0056] Step S12: Establish a workpiece motion chain based on the reference coordinate system, the linear axes having a preset motion relationship with the workpiece to be detected, the workpiece rotation axis, and the workpiece coordinate system.

[0057] Please refer to Figure 5 , in some embodiments, the reference coordinate system is M, the linear axes having a preset motion relationship with the workpiece to be detected are the X-axis and the Y-axis, the workpiece rotation axis is the C-axis, and a workpiece coordinate system W corresponding to the workpiece rotation axis C-axis is constructed during the construction of the workpiece motion chain. Therefore, according to the theory of robot kinematics, the workpiece motion chain M->X->Y->C->W is established.

[0058] Step S2: Construct a corresponding sensor motion chain based on the sensor rotation axis and the laser line scanning sensor. During the construction of the sensor motion chain, a sensor coordinate system corresponding to the laser line scanning sensor is constructed.

[0059] Please refer to Figure 6 , in some embodiments, step S2 constructs a corresponding sensor motion chain based on the sensor rotation axis and the laser line scanning sensor, including steps S21 to S22, which are specifically described below.

[0060] Step S21: Construct a reference coordinate system corresponding to the workpiece to be detected and obtain the translation amount corresponding to the laser line scanning sensor.

[0061] In some embodiments, the reference coordinate system includes a virtual coordinate system constructed according to the X-axis, Y-axis, and Z-axis. Among them, the X-axis, Y-axis, and Z-axis are equivalent to the horizontal axis, vertical axis, and vertical axis in the linear axis. During the construction of the sensor motion chain, a sensor coordinate system corresponding to the laser line scanning sensor will also be constructed. Since when using the laser line scanning sensor S for scanning, the laser line scanning is not a single measurement point, but a line formed by linearly arranging many measurement points, therefore, when constructing the sensor motion chain, it is also necessary to consider the translation amount of the laser line scanning sensor relative to the origin of the sensor coordinate system during line scanning, that is, the translation amount SL corresponding to the laser line scanning sensor.

[0062] Step S22: Establish a sensor motion chain based on the reference coordinate system, the preset axis in the linear axis, the sensor rotation axis, the laser line scanning sensor, and the translation amount.

[0063] Please refer to Figure 7 , in some embodiments, the sensor motion chain can be expressed as M->Z->B->S->SL.

[0064] Please refer to Figure 8 , in some embodiments, in the initial state of the multi-axis measurement system, this reference coordinate system M coincides with the workpiece coordinate system W, and a complete closed-loop motion chain corresponding to the multi-axis measurement system can be formed according to the sensor motion chain and the workpiece motion chain.

[0065] Step S3: Construct a transfer function according to the workpiece motion chain and the sensor motion chain, and construct a kinematic model according to the transfer function and the motion parameters corresponding to the transfer function.

[0066] In some embodiments, constructing a transfer function according to the workpiece motion chain and the sensor motion chain includes:

[0067] U = {x, y, z, θ B , θ C , s, SL}

[0068] Among them, U represents the transfer function, x represents the offset distance corresponding to the X-axis in the linear axis, y represents the offset distance corresponding to the Y-axis in the linear axis, z represents the offset distance corresponding to the Z-axis in the linear axis, θ BRepresents the offset angle corresponding to the sensor rotation axis, θ c Represents the offset angle corresponding to the workpiece rotation axis, s represents the reference measurement point corresponding to the laser line scanning sensor, and SL represents the translation amount corresponding to the laser line scanning sensor.

[0069] In some embodiments, the motion parameters can be expressed as V = (α, v S , ω C , ω B , q B , q s , v SL ) ∈ R 21 , where V represents the motion parameters corresponding to the transfer function, α represents the compensation coefficient, and v S represents the linear velocity vector corresponding to the laser line scanning sensor, and ω C represents the angular velocity vector corresponding to the workpiece rotation axis, and ω B represents the angular velocity vector corresponding to the sensor rotation axis, and q B represents the coordinates of a preset point on the sensor rotation axis, and q s represents the coordinates of a preset point on the laser line scanning sensor, and v SL represents the linear velocity vector corresponding to the translation amount.

[0070] In some embodiments, the motion parameters are expressed as V = (α, v s , ω c , ω B , q B , q s , v SL ) ∈ R 21 , and α = (α XY , α XZ , α YZ ) ∈ R 3 , α XY represents the compensation coefficient between the X-axis and the Y-axis, and α XZ represents the compensation coefficient between the X-axis and the Z-axis, and α YZ represents the compensation coefficient between the Y-axis and the Z-axis. v S = (v SX , v SY , v SZ ) T ∈ R 3 , ||v S || = 1, and v SX represents the linear velocity vector corresponding to the laser line scanning sensor and the X-axis, and v SY represents the linear velocity vector corresponding to the laser line scanning sensor and the Y-axis, and v SZ represents the linear velocity vector corresponding to the laser line scanning sensor and the Z-axis, and T represents the transpose matrix. ω C = (ωCX , ω CY , ω CZ ) T ∈R 3 ,||ω C || = 1, ω CX represents the angular velocity vector corresponding to the workpiece rotation axis and the X-axis, ω CY represents the angular velocity vector corresponding to the workpiece rotation axis and the Y-axis, ω CZ represents the angular velocity vector corresponding to the workpiece rotation axis and the Z-axis, T represents the transpose matrix. ω B = (ω BX , ω BY , ω BZ ) T ∈R 3 ,||ω B || = 1, ω BX represents the angular velocity vector corresponding to the sensor rotation axis and the X-axis, ω BY represents the angular velocity vector corresponding to the sensor rotation axis and the Y-axis, ω BZ represents the angular velocity vector corresponding to the sensor rotation axis and the Z-axis, T represents the transpose matrix. q B = (q BX , 0, q BZ ) T ∈R 3 ,where q BX represents the coordinate of the preset point on the sensor rotation axis and the X-axis, q BZ represents the coordinate of the preset point on the sensor rotation axis and the Z-axis. q S = (q SX , q SY , 0) T ∈R 3 ,where q SX represents the coordinate of the preset point on the laser line scanning sensor and the X-axis, q BY represents the coordinate of the preset point on the laser line scanning sensor and the Y-axis. And regarding the parameter v SL = (v SLX , v SLY , v SLZ ) T ∈R 3 ,||v SL || = 1, v SLX represents the linear velocity vector corresponding to the translation and the X-axis, v SLY represents the linear velocity vector corresponding to the translation and the Y-axis, v SLZ represents the linear velocity vector corresponding to the translation and the Z-axis, T represents the transpose matrix.

[0071] In some embodiments, a kinematic model F(U, V) is constructed according to the transfer function U and the corresponding motion parameter V of the transfer function. Then, any measurement point on the workpiece to be detected can be expressed as P according to the kinematic model w = F(U, V).

[0072] Step S4: Based on the workpiece motion chain, establish a first expression corresponding to the measurement point on the workpiece to be detected, and based on the sensor motion chain, establish a second expression corresponding to the measurement point; the measurement point includes the measurement point in the sensor coordinate system.

[0073] In some embodiments, according to the motion chain and the forward kinematics theory, any point P on the workpiece to be detected can be modeled on two motion chains. Therefore, a first expression corresponding to the measurement point can be established based on the workpiece motion chain, and a second expression corresponding to the measurement point can be established based on the sensor motion chain.

[0074] In some embodiments, establishing a first expression corresponding to the measurement point on the workpiece to be detected based on the workpiece motion chain includes:

[0075] The first expression is P' M = g MX (MX)g MY (MY)g MC (θ MC )g MW (0)P W

[0076] Wherein, P' M represents the measurement point expressed according to the workpiece motion chain in the reference coordinate system, g MX (MX) represents the transformation matrix from the reference coordinate system to the horizontal axis in the linear axis, g MY (MY) represents the transformation matrix from the reference coordinate system to the vertical axis in the linear axis, g MC (θ MC ) represents the transformation matrix from the reference coordinate system to the workpiece rotation axis, g MW (0) represents the transformation matrix from the reference coordinate system to the workpiece coordinate system, P W represents the measurement point of the workpiece to be detected in the sensor coordinate system in the initial state.

[0077] In some embodiments, establishing a second expression corresponding to the measurement point on the workpiece to be detected based on the sensor motion chain includes:

[0078] The second expression is P M = g MZ (MZ)g MB (θ MB )g S (S)g SL (SL)g MS (0)PS

[0079] Among them, P M represents the measurement point expressed according to the sensor kinematic chain in the reference coordinate system, and g MZ (MZ) represents the transformation matrix from the reference coordinate system to the vertical axis in the linear axis, and g MB (θ MB ) represents the transformation matrix from the reference coordinate system to the sensor rotation axis, and g S (S) represents the transformation matrix corresponding to the laser scanning sensor, and g SL (SL) represents the transformation matrix of the translation amount corresponding to the laser line scanning sensor, and g MS (0) represents the transformation matrix from the reference coordinate system to the laser line scanning sensor, and P S represents the measurement point in the sensor coordinate system corresponding to the laser line scanning sensor.

[0080] Since the measurement point P' M expressed according to the workpiece kinematic chain in the reference coordinate system is M equal to the measurement point P M expressed according to the sensor kinematic chain in the reference coordinate system, that is, P' M = P

[0081] Step S5: Simultaneously solve according to the first expression, the second expression, the kinematic model and the kinematic screw theory to obtain the expansion formula of the measurement point, and calibrate the model parameters in the expansion formula to obtain the final workpiece measurement value; the final workpiece measurement value includes the measurement value in the workpiece coordinate system.

[0082] In some embodiments, by jointly solving according to the first expression, the second expression and the kinematic model, the obtained expression is:

[0083]

[0084] In some embodiments, according to the kinematic screw theory, the screw coordinate is defined as: ξ = (v T ω T ) T , where v is the linear velocity vector, ω is the angular velocity vector, and T is the transpose matrix. Therefore, according to the kinematic screw theory, each axis on the workpiece kinematic chain and the sensor kinematic chain can be defined in the following form:

[0085] ξ X = (1, 0, 0, 0, 0, 0) T

[0086] ξ Y =(α XY , 1, 0, 0, 0, 0) T

[0087] ξ Z =(α XZ , α YZ , 1, 0, 0, 0) T

[0088] ξ C =(0, 0, 0, ω CX , ω CY , ω CZ ) T

[0089] ξ B =(v BX , v BY , v BZ , ω BX , ω BY , ω BZ ) T

[0090] ξ S =(v SX , v SY , vS Z , 0, 0, 0) T

[0091] ξ SL =(v LX , v LY , v LZ , 0, 0, 0) T

[0092] Among them, ξ X represents the screw parameter corresponding to the horizontal axis in the linear axis, ξ Y represents the screw parameter corresponding to the vertical axis in the linear axis, ξ Z represents the screw parameter corresponding to the vertical axis in the linear axis, ξ C represents the screw parameter corresponding to the station rotation axis, ξ B represents the screw parameter corresponding to the sensor rotation axis, ξ S represents the screw parameter corresponding to the laser line scanning sensor, ξ SL represents the screw parameter corresponding to the translation amount.

[0093] In some embodiments, according to the rigid body motion and the screw coordinate ξ, it can be known that the motion screw is defined by a 4x4 matrix as where v = -ω×q, then the rigid body motion can be expressed as the exponential mapping of the screw, that is, expressed as If the rigid body motion is a pure translational motion, then v ∈ R 3 , ||v|| = 1,

[0094] In some embodiments, in the initial state, the transformation matrix at the end of the sensor is defined as gMS(0) = I4×4, and the measurement point P of the workpiece to be detected in the sensor coordinate system in the initial state S = (0, 0, 0, 1) T .

[0095] In some embodiments, combining the above exponential coordinate representation forms of rigid body motion and screw theory, the expression:

[0096]

[0097] can be converted into the expansion of the measurement point:

[0098]

[0099] Please refer to Figure 9 , in some embodiments, in step S5, the model parameters in the expansion are calibrated to obtain the final workpiece measurement value, including steps S51 to S52, which are specifically described below.

[0100] Step S51: Use a preset non-linear optimization algorithm to optimize the model parameters in the expansion to obtain optimized model parameters.

[0101] Step S52: Substitute the optimized model parameters into the expansion of the measurement point to obtain the final workpiece measurement value.

[0102] In some embodiments, the final workpiece measurement value is in the workpiece coordinate system, thus realizing the processing of seamless splicing and transformation of the workpiece to be detected without marked points.

[0103] Please refer to Figure 10 , in some embodiments of the present invention, a workpiece detection device is provided, which is applied in a multi-axis measurement system. The multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis, and a laser line scanning sensor. The workpiece detection device includes a workpiece motion chain construction module 10, a sensor motion chain construction module 20, a kinematic model construction module 30, and a measurement point calculation module 40.

[0104] The workpiece motion chain construction module 10 is used to construct a corresponding workpiece motion chain based on the workpiece to be detected. During the construction of the workpiece motion chain, a workpiece coordinate system corresponding to the workpiece rotation axis is constructed.

[0105] The sensor kinematic chain construction module 20 is used to construct a corresponding sensor kinematic chain based on the sensor rotation axis and the laser line scanning sensor, wherein a sensor coordinate system corresponding to the laser line scanning sensor is constructed in the process of constructing the sensor kinematic chain.

[0106] The kinematic model building module 30 is used to build a transfer function according to the workpiece kinematic chain and the sensor kinematic chain, and to build a kinematic model according to the transfer function and the kinematic parameters corresponding to the transfer function.

[0107] The measuring point calculation module 40 is used to establish a first expression corresponding to the measuring point on the workpiece to be detected based on the workpiece motion chain, and to establish a second expression corresponding to the measuring point based on the sensor motion chain; the measuring point includes the measuring point in the sensor coordinate system, and the first expression, the second expression, the kinematic model and the motion spiral theory are jointly solved to obtain the expansion of the measuring point, and the model parameters in the expansion are calibrated to obtain the final workpiece measurement value; the final workpiece measurement value includes the measurement value in the workpiece coordinate system.

[0108] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0109] The above specific examples are used to illustrate the present invention, which are only used to help understand the present invention and are not used to limit the present invention. For those skilled in the art to which the present invention belongs, some simple deductions, modifications or substitutions can be made according to the idea of the present invention.

Claims

1. A workpiece detection method is applied in a multi-axis measurement system, and the multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis, and a laser line scanning sensor; characterized in that, The multi-axis measurement system further includes a linear axis, and the workpiece detection method includes: Constructing a reference coordinate system corresponding to the workpiece to be detected, where the reference coordinate system corresponding to the workpiece to be detected includes a coordinate system constructed according to the linear axis; Establishing a workpiece motion chain based on the reference coordinate system corresponding to the workpiece to be detected, the linear axis having a preset motion relationship with the workpiece to be detected, the workpiece rotation axis, and the workpiece coordinate system. Wherein, during the construction of the workpiece motion chain, a workpiece coordinate system corresponding to the workpiece rotation axis is constructed; Obtaining the translation amount corresponding to the laser line scanning sensor, and establishing a sensor motion chain based on the reference coordinate system corresponding to the workpiece to be detected, a preset axis in the linear axis, the sensor rotation axis, the laser line scanning sensor, and the translation amount. Wherein, during the construction of the sensor motion chain, a sensor coordinate system corresponding to the laser line scanning sensor is constructed; Constructing a transfer function according to the workpiece motion chain and the sensor motion chain, and constructing a kinematic model according to the transfer function and the motion parameters corresponding to the transfer function; Establishing a first expression corresponding to a measurement point on the workpiece to be detected based on the workpiece motion chain, and establishing a second expression corresponding to the measurement point based on the sensor motion chain; the measurement point includes a measurement point in the sensor coordinate system; Performing a simultaneous solution according to the first expression, the second expression, the kinematic model, and the motion screw theory to obtain an expansion formula of the measurement point, and performing a calibration process on the model parameters in the expansion formula to obtain a final workpiece measurement value; the final workpiece measurement value includes a measurement value in the workpiece coordinate system.

2. The method according to claim 1, wherein The linear axis includes a horizontal axis, a vertical axis, and a vertical axis. A reference coordinate system corresponding to the linear axis is constructed according to the horizontal axis, the vertical axis, and the vertical axis. The workpiece rotation axis is set at the intersection of the horizontal axis and the vertical axis in the reference coordinate system corresponding to the linear axis, and the sensor rotation axis is set perpendicular to the vertical axis in the reference coordinate system corresponding to the linear axis; the workpiece to be detected is placed on the workpiece rotation axis, the laser line scanning sensor is set on the sensor rotation axis, and the laser line scanning sensor is used to linearly scan the workpiece to be detected.

3. The method according to claim 1, characterized in that The constructing a transfer function according to the workpiece motion chain and the sensor motion chain includes: U = {x, y, z, θ B, θ C, s, SL} Among them, U represents the transfer function, x represents the offset distance corresponding to the X-axis in the linear axis, y represents the offset distance corresponding to the Y-axis in the linear axis, z represents the offset distance corresponding to the Z-axis in the linear axis, and θ B represents the offset angle corresponding to the rotation axis of the sensor, and θ c represents the offset angle corresponding to the rotation axis of the workpiece, s represents the reference measurement point corresponding to the laser line scanning sensor, and SL represents the translation amount corresponding to the laser line scanning sensor.

4. The method according to claim 2, characterized in that, The establishing a second expression corresponding to a measurement point on the workpiece to be detected based on the sensor motion chain includes: The second expression is P M = g MZ (MZ)g MB (θ MB )g S (S)g SL (SL)g MS (0)P S where, P M represents a measurement point expressed according to the sensor kinematic chain in the reference coordinate system corresponding to the linear axis, g MZ (MZ) represents a transformation matrix from the reference coordinate system corresponding to the linear axis to the vertical axis in the linear axis, g MB (θ MB ) represents a transformation matrix from the reference coordinate system corresponding to the linear axis to the sensor rotation axis, g S (S) represents a transformation matrix corresponding to the laser scanning sensor, g SL (SL) represents a transformation matrix of the translation amount corresponding to the laser line scanning sensor, g MS (0) represents a transformation matrix from the reference coordinate system corresponding to the linear axis to the laser line scanning sensor, P S represents a measurement point in the sensor coordinate system corresponding to the laser line scanning sensor.

5. The method according to claim 1, wherein The performing a calibration process on the model parameters in the expansion formula to obtain a final workpiece measurement value includes: Using a preset non-linear optimization algorithm to optimize the model parameters in the expansion formula to obtain optimized model parameters; Substituting the optimized model parameters into the expansion formula of the measurement point to obtain a final workpiece measurement value.

6. A workpiece detection device is applied in a multi-axis measurement system, and the multi-axis measurement system includes a workpiece rotation axis, a sensor rotation axis, and a laser line scanning sensor; characterized in that, The multi-axis measurement system further includes a linear axis, and the workpiece detection device includes: The workpiece motion chain construction module is used to construct a reference coordinate system corresponding to the workpiece to be detected. The reference coordinate system corresponding to the workpiece to be detected includes a coordinate system constructed according to the linear axis. Based on the reference coordinate system corresponding to the workpiece to be detected, the linear axis having a preset motion relationship with the workpiece to be detected, the workpiece rotation axis, and the workpiece coordinate system, a workpiece motion chain is established. Among them, during the construction of the workpiece motion chain, the workpiece coordinate system corresponding to the workpiece rotation axis is constructed. The sensor motion chain construction module is used to obtain the translation amount corresponding to the laser line scanning sensor. Based on the reference coordinate system corresponding to the workpiece to be detected, the preset axis in the linear axis, the sensor rotation axis, the laser line scanning sensor, and the translation amount, a sensor motion chain is established. Among them, during the construction of the sensor motion chain, the sensor coordinate system corresponding to the laser line scanning sensor is constructed. The kinematic model construction module is used to construct a transfer function according to the workpiece motion chain and the sensor motion chain, and construct a kinematic model according to the transfer function and the motion parameters corresponding to the transfer function. The measurement point calculation module is used to establish a first expression corresponding to the measurement point on the workpiece to be detected based on the workpiece motion chain, and establish a second expression corresponding to the measurement point based on the sensor motion chain. The measurement point includes the measurement point in the sensor coordinate system. According to the first expression, the second expression, the kinematic model, and the motion screw theory, a simultaneous solution is performed to obtain the expansion formula of the measurement point, and the model parameters in the expansion formula are calibrated to obtain the final workpiece measurement value. The final workpiece measurement value includes the measurement value in the workpiece coordinate system.

7. A workpiece detection device, characterized in that, It includes: A memory for storing programs. A processor for implementing the method according to any one of claims 1-5 by executing the program stored in the memory.

8. A computer-readable storage medium, characterized in that, A program is stored on the medium, and the program can be executed by the processor to implement the method according to any one of claims 1-5.

Images