Parameter acquisition method of mechanical arm

Abstract

The invention belongs to the field of mechanical arm kinematics parameter identification, and relates to a mechanical arm parameter obtaining method which comprises the steps that according to the working state of a mechanical arm, a sensor is used for collecting target tail end poses when the mechanical arm is in multiple different preset configurations; wherein the mechanical arms comprise a macro mechanical arm and a micro mechanical arm, and according to the working state of the mechanical arms, the macro mechanical arm and the micro mechanical arm are separated into two mechanical arms, or the macro mechanical arm and the micro mechanical arm are connected in series to form a macro-micro mechanical arm; and according to the target tail end poses collected in the two working states of the mechanical arm, the kinematics parameters of the macro mechanical arm and the micro mechanical arm in the working state are adjusted, and the final kinematics parameters of the macro mechanical arm and the micro mechanical arm are obtained.

Description

Technical Field

[0001] The invention belongs to the field of mechanical arm kinematic parameter identification and relates to a method for obtaining parameters of a mechanical arm. Background Art

[0002] Macro and micro robotic arms are used in aerospace, precision manufacturing, medical surgery and other scenarios because they can take into account the characteristics of large-scale rapid transfer and fine operation. Their operating accuracy is crucial to ensure safe operation and smooth mission. During the long-term use of the robotic arm, processing and assembly, thermal expansion and contraction, plastic deformation under force, joint zero position error, etc. may cause different degrees of changes in the actual kinematic parameters. If the robot is still controlled according to the kinematic parameters when the robot was designed, the actual end position will be different from the expected one, bringing risks such as collision and accidental force, affecting the safe and smooth completion of the task. Robot arm kinematic parameter identification is an important way for the robot arm to autonomously obtain accurate kinematic parameters. The control accuracy is improved by collecting the position and posture of the robot arm in a variety of different configurations, calculating its parameter error, and adjusting the kinematic parameters.

[0003] In particular, macro-micro manipulators often have a high degree of redundant freedom, and high redundancy may cause the kinematic parameters to be coupled with each other, making it difficult to fully obtain their accurate values ​​through calculation; obtaining kinematic parameters with higher degrees of freedom requires collecting and processing more configuration and posture data, and it takes a certain amount of time for a high-degree-of-freedom manipulator to move between different configurations and wait for its vibration to decay; therefore, the application of existing parameter acquisition methods to macro-micro manipulators will mainly face the following problems:

[0004] a. The existing kinematic parameter acquisition methods mainly focus on the compensation of the end-point posture error. When used for macro-micro manipulators, the obtained parameter solutions are not unique and inaccurate.

[0005] b. The existing kinematic parameter acquisition method needs to improve the time consumption in calculating parameter errors;

[0006] c. There are many configurations of target terminal positions that need to be collected, and the collection efficiency needs to be improved;

[0007] d. When the robotic arm is reinstalled on the base, the parameters of the entire robotic arm need to be reacquired, and the efficiency needs to be improved. Summary of the invention

[0008] In view of this, the present invention provides a method for obtaining parameters of a robot arm, comprising:

[0009] According to the working state of the robotic arm, the target end position of the robotic arm when it is in a plurality of different preset configurations is collected by using sensors; wherein the robotic arm includes a macro robotic arm and a micro robotic arm, and the working state of the robotic arm includes the macro robotic arm and the micro robotic arm being separated into two robotic arms, or the macro robotic arm and the micro robotic arm being connected in series into a macro-micro robotic arm, and the preset configuration represents the joint angle that can be actually reached by the macro robotic arm, the micro robotic arm, or the macro-micro robotic arm;

[0010] According to the target end poses collected in two working states of the robot arm respectively, the kinematic parameters of the working state in which the macro robot arm and the micro robot arm are connected in series into one macro-micro robot arm are adjusted to obtain the final kinematic parameters of the macro-micro robot arm.

[0011] In the above method, according to the working state of the robot arm, the target end position when the robot arm is in a plurality of different preset configurations is collected by using sensors, including:

[0012] In a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, when the macro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a first end position of the macro-mechanical arm when it is in each preset configuration, and when the micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a second end position of the micro-mechanical arm when it is in each preset configuration, and the first end position and the second end position are used as target end positions;

[0013] When the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-micro-robotic arm, when the macro-micro-robotic arm moves to multiple different preset configurations, the sensor is used to collect the third end position of the macro-micro-robotic arm in each preset configuration, and the third end position is used as the target end position.

[0014] In the above method, according to the target end poses collected in two working states of the robot arm respectively, the kinematic parameters of the working state in which the macro robot arm and the micro robot arm are connected in series as a macro-micro robot arm are adjusted to obtain the final kinematic parameters of the macro-micro robot arm, including:

[0015] For a working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, iteratively calculating errors of all kinematic parameters of the macro-robotic arm according to the acquired first end pose, and adjusting the kinematic parameters of the macro-robotic arm according to the errors;

[0016] For a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, iteratively calculating errors of all kinematic parameters of the micro-mechanical arm according to the acquired second end posture, and adjusting the kinematic parameters of the micro-mechanical arm according to the errors;

[0017] According to the adjusted kinematic parameters of the macro-robotic arm and the adjusted kinematic parameters of the micro-robotic arm, the shared kinematic parameters of the macro-microrobotic arm are adjusted; for the working state in which the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, according to the collected third end posture, the errors of all kinematic parameters of the micro-robotic arm are iteratively calculated, and, according to the errors, the differential kinematic parameters of the macro-microrobotic arm are adjusted to obtain the final kinematic parameters of the macro-microrobotic arm; wherein the shared kinematic parameters are kinematic parameters that belong to the working state in which the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-microrobotic arm, and also exist in the working state in which the macro-robotic arm and the micro-robotic arm are separated into two robotic arms; the differential kinematic parameters are kinematic parameters that belong to the working state in which the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-microrobotic arm, but are not kinematic parameters of the shared kinematic parameters.

[0018] The above method is characterized in that, in a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, when the macro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a first end position of the macro-mechanical arm in each preset configuration, including:

[0019] Randomly generated for the macro robot preset configurations, where Indicates rounding up, n L represents the degree of freedom of the macro robot, p is a positive number;

[0020] The sensors are used to collect the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator when the macro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator. The position and posture are recorded in the form of to obtain the first terminal posture.

[0021] The above method is characterized in that, in a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, when the micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect the second end position of the micro-mechanical arm in each preset configuration, including:

[0022] Randomly generate for micro-robotic arms preset configurations, where n S represents the degrees of freedom of the micro-manipulator;

[0023] The sensors are used to collect the position and posture of the end of the micro-manipulator relative to the micro-manipulator base when the micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the micro-manipulator relative to the micro-manipulator base. The position and posture are recorded in the form of to obtain the second terminal posture.

[0024] The above method is characterized in that, in a working state where the macro-mechanical arm and the micro-mechanical arm are connected in series to form a macro-micro-mechanical arm, when the macro-micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a third end position of the macro-micro-mechanical arm in each preset configuration, including:

[0025] Randomly generate for macro-micro robotic arms preset configurations, n' C is the number of coordinate systems with different kinematic parameters;

[0026] The sensors are used to collect the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator when the macro-micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator. The position and posture are recorded in the form of to obtain the third terminal posture.

[0027] The above method is characterized in that, for the working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, errors of all kinematic parameters of the macro-robotic arm are iteratively calculated according to the acquired first end pose, and kinematic parameters of the macro-robotic arm are adjusted according to the errors, including:

[0028] In each iteration, for each preset configuration of the macro robot, the nominal kinematic parameter KP L nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0029] According to the nominal end position The first end position acquired Get the antisymmetric matrix:

[0030]

[0031] Among them, d x d y d z They represent the moving distance along the x, y, and z axes in the terminal coordinate system, respectively. x , δ y , δ z Respectively represent the rotation angles around the x, y, and z axes in the terminal coordinate system;

[0032] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0033]

[0034] in, ∨ is an operator that converts an antisymmetric matrix into a differential motion vector;

[0035] According to the nominal kinematic parameter KP L nominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gL i :

[0036]

[0037] This gives a system of equations in matrix form:

[0038]

[0039] in, To all The matrix obtained by combining in column form is, For all J gL i The matrix obtained by combining in column form is, is the error of all kinematic parameters of the macro robot, Contains (q·(n L +1)) components;

[0040] Find the equation Solution in the least squares sense:

[0041]

[0042] in, + represents pseudo-inverse;

[0043] Adjust the nominal kinematic parameters of the macro robot:

[0044]

[0045] until When each component in is less than the preset threshold, the KP obtained in the last iteration is L nominal As the kinematic parameter KP of the adjusted macro robot L calibrated .

[0046] In the above method, for the working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, the errors of all kinematic parameters of the micro-robotic arm are iteratively calculated according to the acquired second end posture, and the kinematic parameters of the micro-robotic arm are adjusted according to the errors, including:

[0047] In each iteration, for each preset configuration of the micromanipulator, the nominal kinematic parameter KP S nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0048] According to the nominal end position The second end position acquired Get the antisymmetric matrix:

[0049]

[0050] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0051]

[0052] According to the nominal kinematic parameters KP of the micromanipulator S nominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gS i :

[0053]

[0054] This gives a system of equations in matrix form:

[0055]

[0056] in, To all The matrix obtained by combining in column form is, For all J gS i The matrix obtained by combining in column form is, is the error of all kinematic parameters of the micromanipulator, Contains (q·(n S +1)) components;

[0057] Find the equation Solution in the least squares sense:

[0058]

[0059] Adjust the nominal kinematic parameters of the micromanipulator:

[0060]

[0061] until When each component in is less than the preset threshold, the KP obtained in the last iteration is S nominal As the kinematic parameter KP of the adjusted micromanipulator S calibrated .

[0062] In the above method, according to the adjusted kinematic parameters of the macro-micro robotic arm and the adjusted kinematic parameters of the micro-robotic arm, the common kinematic parameters of the macro-micro robotic arm are adjusted, and, according to the collected third end posture, the differential kinematic parameters of the macro-micro robotic arm are adjusted to obtain the final kinematic parameters of the macro-micro robotic arm, including:

[0063] For the working state where the macro-mechanical arm and the micro-mechanical arm are connected in series to form a macro-micro-mechanical arm, for each parameter element in the kinematic parameters shared by the macro-micro-mechanical arm, if the parameter element exists in the macro-mechanical arm, it is changed to be the same as the corresponding parameter element in the kinematic parameters of the macro-mechanical arm after adjustment; if the parameter element exists in the micro-mechanical arm, it is changed to be the same as the corresponding parameter element in the kinematic parameters of the micro-mechanical arm after adjustment;

[0064] According to the third terminal pose acquired, iteratively calculate the errors of all kinematic parameters of the micro-mechanical arm, and adjust the differential kinematic parameters of the macro-micro-mechanical arm according to the errors. In each iteration, for each preset configuration of the macro-micro-mechanical arm, according to the nominal kinematic parameters KP C nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0065] According to the nominal end position The third terminal pose collected Get the antisymmetric matrix:

[0066]

[0067] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0068]

[0069] According to the nominal kinematic parameter KP C nominal , and based on the mapping relationship between the error of the difference kinematic parameters and the end posture error, the error Jacobian matrix J′ corresponding to the difference kinematic parameters is calculated gC i :

[0070]

[0071] Among them, KP′ C nominal are the nominal differential kinematic parameters;

[0072] This gives a system of equations in matrix form:

[0073]

[0074] in, To all The matrix is ​​combined in column form, where To convert all J′ gC i The matrix obtained by combining in column form is, is the error of the difference kinematic parameters, Contains (q·n′ C ) portions;

[0075] Find the equation Solution in the least squares sense:

[0076]

[0077] Adjust the differential kinematic parameters of the macro-micro manipulator:

[0078]

[0079] until When each component in is less than the preset threshold, the KP′ obtained in the last iteration is used C nominal Replace KP C nominal The difference kinematic parameters in the adjusted macro-micromanipulator are obtained by C calibrated , as the final kinematic parameters of the macro-micro robotic arm.

[0080] The technical solution of the embodiment of the present invention has the following beneficial effects.

[0081] Compared with the existing method of directly obtaining kinematic parameters by treating the macro-micro robotic arm in series working state as a whole:

[0082] a. The iterative error solution algorithm directly involves lower degrees of freedom, lower degree of kinematic parameter coupling, and the obtained kinematic parameters are significantly more accurate;

[0083] b. The number of trigonometric function operations is reduced during the solution process, and the total time consumed for numerical operations is shorter;

[0084] c. The macro-manipulator and the micro-manipulator can collect the target end poses under most preset configurations in parallel to improve the collection efficiency;

[0085] d. A method for obtaining local kinematic parameters is given. When the macro-micro robotic arm is separated and reconnected in series, only a small number of target end poses under preset configurations need to be collected to calculate the local kinematic parameter errors and make adjustments to make the kinematic model of the entire macro-micro robotic arm accurate again, without the need to collect a large number of target end poses under preset configurations to recalculate the kinematic parameter errors of the entire macro-micro robotic arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creativity and labor.

[0087] Figure 1It is a schematic flow chart of a method for obtaining parameters of a robotic arm provided in an embodiment of the present invention;

[0088] Figure 2 It is a schematic diagram of the coordinate system of the macro-mechanical arm provided in an embodiment of the present invention, in which the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms in a working state;

[0089] Figure 3 It is a schematic diagram of the micro-mechanical arm coordinate system in a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms according to an embodiment of the present invention;

[0090] Figure 4 It is a schematic diagram of a macro-micro robotic arm coordinate system in a working state where a macro-mechanical arm and a micro-mechanical arm are connected in series to form a macro-micro robotic arm provided by an embodiment of the present invention;

[0091] Figure 5 It is a schematic diagram comparing the kinematic parameters of a macro-micromechanical arm and a macro-micromechanical arm provided by an embodiment of the present invention;

[0092] Figure 6 is a schematic diagram of the position error of the end of the macro-micro mechanical arm before and after the application of the parameter acquisition method and the comparison method provided in the embodiment of the present invention;

[0093] Figure 7 is a schematic diagram of the angle error of the end of the macro-micro mechanical arm before and after the application of the parameter acquisition method and the comparison method provided in the embodiment of the present invention;

[0094] Figure 8 It is a schematic diagram of the error between the kinematic length parameter and the actual value after the parameter acquisition method and the comparison method provided in the embodiment of the present invention are applied;

[0095] Fig. 9 It is a schematic diagram of the error between kinematic angle parameters and actual values ​​after applying the parameter acquisition method and comparison method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0096] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0097] It should be clear that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0098] The specific embodiment of the present invention provides a method for obtaining parameters of a robot arm. Figure 1 A schematic flow chart of a method for obtaining parameters of a robotic arm provided in an example of the present invention, the method comprising the following steps.

[0099] Step 101, according to the working state of the robotic arm, using sensors to collect the target end posture of the robotic arm when it is in multiple different preset configurations; wherein the robotic arm includes a macro robotic arm and a micro robotic arm, and the working state of the robotic arm includes the macro robotic arm and the micro robotic arm being separated into two robotic arms, or the macro robotic arm and the micro robotic arm being connected in series into a macro-micro robotic arm.

[0100] In the embodiment of the present invention, the working state in which the macro robotic arm and the micro robotic arm are separated into two robotic arms is referred to as the separated working state, and the working state in which the macro robotic arm and the micro robotic arm are connected in series into one macro-micro robotic arm is referred to as the series working state; the preset configuration characterizes the joint angle that the macro robotic arm, the micro robotic arm or the macro-micro robotic arm can actually reach, for example, a possible preset configuration of the macro robotic arm is [-10, 0, 10, 0, 30, 60, 90] (unit: °).

[0101] In the embodiment of the present invention, the macro-robot arm and the micro-robot arm involved are both 7-DOF rotation joint robot arms. In the separated working state, a coordinate system is established for the macro-robot arm, coordinate systems 1L, 2L, ..., 7L are established for each link of the macro-robot arm, and coordinate systems 0L and 8L are established for the base and the end effector. Figure 2 As shown in the figure, x 0L represents the x-axis of the macro robot arm 0L coordinate system, and the other labels are similar; establish a coordinate system for the micro robot arm, establish coordinate systems 1S, 2S, ..., 7S for each link of the micro robot arm, and establish coordinate systems 0S and 8S for the base and end effector, such as Figure 3 As shown in the figure, x 0S represents the x-axis of the micro-manipulator 0S coordinate system, and the other marks are similar.

[0102] In the serial working state, the macro-robotic arm and the micro-robotic arm are serially connected into a macro-micro-robotic arm by means of a combined adapter, and the micro-robotic arm is connected in series to the end of the macro-robotic arm. At this time, the combined adapter is fixedly connected to the macro-robotic arm and the micro-robotic arm respectively. The degree of freedom of the macro-micro-robotic arm is 14. Coordinate systems 1L, 2L, ..., 14L are established for each link of the macro-micro-robotic arm, and coordinate systems 0L and 15L are established for the base and the end effector, as shown in Figure 4 As shown in the figure, Σ 0C / Σ 0L Indicates the origin position of the coordinate system 0C, and this position coincides with the origin position of the coordinate system 0L. The same applies to other numbers.

[0103] The kinematic model of each manipulator is established using the modified Denavit-Hartenberg method to represent the relative position relationship between coordinate systems. The kinematic parameters include α, a, θ, d, β, The relationship with the kinematic parameters is:

[0104]

[0105] Among them, Rot(x,α i-1 ) represents the rotation angle α around the x-axis i-1 The homogeneous transformation matrix, Trans(x,a i-1 ) represents the movement distance a along the x-axis i-1 The homogeneous transformation matrix of , and the rest are similar;

[0106] The vectors composed of the nominal kinematic parameters of the macro and micro manipulators are denoted as KP L nominal and KP S nominal , each vector contains 5·(7+1)=40 components; the vectors composed of the nominal kinematic parameters of the macro-micro manipulator are denoted as KP C nominal , each vector contains 5·(14+1)=75 components.

[0107] When the macro-manipulator and the micro-manipulator are separated into two working arms, the macro-manipulator randomly generates preset configurations, where Indicates rounding up, n L =7 represents the degree of freedom of the macro robot, and p is a positive number;

[0108] The sensors are used to collect the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator when the macro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator. The position and posture are recorded in the form of to obtain the first terminal posture.

[0109] When the macro-robotic arm and the micro-robotic arm are separated into two working arms, the micro-robotic arm randomly generates preset configurations, where n S =7 represents the degree of freedom of the micro-manipulator;

[0110] The sensors are used to collect the position and posture of the end of the micro-manipulator relative to the micro-manipulator base when the micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the micro-manipulator relative to the micro-manipulator base. The position and posture are recorded in the form of to obtain the second terminal posture.

[0111] When the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-micro-robotic arm, the macro-micro-robotic arm randomly generates preset configurations, where n' C =2;

[0112] The sensors are used to collect the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator when the macro-micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator. The position and posture are recorded in the form of to obtain the third terminal posture.

[0113] Step 102, according to the target end postures collected in two working states of the robot arm respectively, adjust the kinematic parameters of the macro-robotic arm and the micro-robotic arm in the working state of a macro-micro-robotic arm connected in series to obtain the final kinematic parameters of the macro-micro-robotic arm.

[0114] In the embodiment of the present invention, for the working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, the errors of all kinematic parameters of the macro-robotic arm are iteratively calculated according to the acquired first end posture, and the kinematic parameters of the macro-robotic arm are adjusted according to the errors. Each iteration process includes:

[0115] For each preset configuration of the macro robot, according to the nominal kinematic parameter KP L nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0116] According to the nominal end position The first end position acquired Get the antisymmetric matrix:

[0117]

[0118] Among them, d x ,d y ,d z They represent the moving distance along the x, y, and z axes in the terminal coordinate system, respectively. x , δ y , δ z Respectively represent the rotation angles around the x, y, and z axes in the terminal coordinate system;

[0119] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0120]

[0121] in, ∨ is an operator that converts an antisymmetric matrix into a differential motion vector;

[0122] According to the nominal kinematic parameter KP L nominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gL i :

[0123]

[0124] This gives a system of equations in matrix form:

[0125]

[0126] in, To all The matrix obtained by combining in column form is, For all J gL i The matrix obtained by combining in column form is, is the error of all kinematic parameters of the macro robot, Contains (q·(n L +1)) components;

[0127] Find the equation Solution in the least squares sense:

[0128]

[0129] in, + represents pseudo-inverse;

[0130] Adjust the nominal kinematic parameters of the macro robot:

[0131]

[0132] until When each component in is less than the preset threshold, the KP obtained in the last iteration is L nominal As the kinematic parameter KP of the adjusted macro robot L calibrated .

[0133] For the working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, the errors of all kinematic parameters of the micro-mechanical arm are iteratively calculated according to the acquired second end posture, and the kinematic parameters of the micro-mechanical arm are adjusted according to the errors. Each iteration process includes:

[0134] For each preset configuration of the micromanipulator, according to the nominal kinematic parameter KP S nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0135] According to the nominal end position The second end position acquired Get the antisymmetric matrix:

[0136]

[0137] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0138]

[0139] According to the nominal kinematic parameters KP of the micromanipulator S nominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gS i :

[0140]

[0141] This gives a system of equations in matrix form:

[0142]

[0143] in, To all The matrix obtained by combining in column form is, For all J gS i The matrix obtained by combining in column form is, is the error of all kinematic parameters of the micromanipulator, Contains (q·(n S +1)) components;

[0144] Find the equation Solution in the least squares sense:

[0145]

[0146] Adjust the nominal kinematic parameters of the micromanipulator:

[0147]

[0148] until When each component in is less than the preset threshold, the KP obtained in the last iteration is S nominal As the kinematic parameter KP of the adjusted micromanipulator S calibrated .

[0149] By analyzing the composition differences of the kinematic parameters under the two working states in the embodiment of the present invention, the kinematic parameters of the macro-micro robotic arm are divided into common kinematic parameters and differential kinematic parameters; wherein the common kinematic parameters are kinematic parameters that belong to the working state where the macro robotic arm and the micro robotic arm are connected in series to form a macro-micro robotic arm, and also exist in the working state where the macro robotic arm and the micro robotic arm are separated into two robotic arms; the differential kinematic parameters are kinematic parameters that belong to the working state where the macro robotic arm and the micro robotic arm are connected in series to form a macro-micro robotic arm, but are not common kinematic parameters. Figure 5As shown, in a specific embodiment of the present invention, when the macro and micro robotic arms are fixedly connected to each other by means of a combined adapter, the macro robotic arm 7L coordinate system and the micro robotic arm 1S coordinate system become adjacent link coordinate systems. After the relative posture relationship between the two is expressed by new kinematic parameters, it is no longer necessary to express the relative posture relationship between the macro robotic arm 7L and the 8L coordinate system, and between the micro robotic arm 0S coordinate system and the 1S coordinate system; when the base of the macro robotic arm is reinstalled, the relative posture relationship between the macro robotic arm 1L coordinate system and the macro robotic arm 0L coordinate system May change; the kinematic parameters used to represent the relative posture relationship between the macro-robotic arm 8L coordinate system and the micro-robotic arm 0S coordinate system on both sides of the combined adapter cannot be obtained in the separated working state and do not need to be obtained in the series working state; therefore, the series working state will reduce the kinematic parameters of 3 coordinate systems and add 2 coordinate systems compared to the separated state. At this time, the common kinematic parameters include 2C~7C (2L~7L) and 9C~15C (2S~8S), and the difference kinematic parameters include 1C (1L) and 8C.

[0150] According to the adjusted kinematic parameters of the macro-robotic arm and the adjusted kinematic parameters of the micro-robotic arm, the common kinematic parameters of the macro-microrobotic arm are replaced. The adjustment process described here is that for the working state in which the macro-robotic arm and the micro-robotic arm are connected in series as a macro-microrobotic arm, for each parameter element in the common kinematic parameters of the macro-microrobotic arm, if the parameter element exists in the macro-robotic arm, it is changed to be the same as the corresponding parameter element in the adjusted kinematic parameters of the macro-robotic arm; if the parameter element exists in the micro-robotic arm, it is changed to be the same as the corresponding parameter element in the adjusted kinematic parameters of the micro-robotic arm; in this embodiment of the present invention, the kinematic parameters of the coordinate system 2C~7C are set to be equal to the kinematic parameters of 2L~7L, and the kinematic parameters of 9C~15C are set to be equal to the kinematic parameters of 2S~8S.

[0151] For the working state where the macro-mechanical arm and the micro-mechanical arm are separated into two robotic arms, the errors of all kinematic parameters of the micro-mechanical arm are iteratively calculated according to the third terminal pose acquired, and the differential kinematic parameters of the macro-micro-mechanical arm are adjusted according to the errors to obtain the final kinematic parameters of the macro-micro-mechanical arm. Each iteration process includes:

[0152] For each preset configuration of the macro-micromanipulator, according to the nominal kinematic parameter KP C nominal , and based on the forward kinematics algorithm, calculate the nominal end pose

[0153] According to the nominal end position The third terminal pose collected Get the antisymmetric matrix:

[0154]

[0155] Convert the antisymmetric matrix into a differential motion vector In the form of:

[0156]

[0157] According to the nominal kinematic parameter KP C nominal , and based on the mapping relationship between the error of the difference kinematic parameters and the end posture error, the error Jacobian matrix J′ corresponding to the difference kinematic parameters is calculated gC i :

[0158]

[0159] Among them, KP′ C nominal are the nominal differential kinematic parameters;

[0160] This gives a system of equations in matrix form:

[0161]

[0162] in, To all The matrix is ​​combined in column form, where To convert all J′ gC i The matrix obtained by combining in column form is, is the error of the difference kinematic parameters, Contains (q·n′ C ) portions;

[0163] Find the equation Solution in the least squares sense:

[0164]

[0165] Adjust the differential kinematic parameters of the macro-micro manipulator:

[0166]

[0167] until When each component in is less than the preset threshold, the KP' obtained in the last iteration is used. C nominal Replace KP C nominal The difference kinematic parameters in the adjusted macro-micromanipulator are obtained by C calibrated , as the final kinematic parameters of the macro-micro robotic arm.

[0168] According to the above method provided in the embodiment of the present invention, a simulation experiment is carried out:

[0169] The kinematic models of the macro-manipulator, micro-manipulator and macro-micro-manipulator are established. Figure 2 , Figure 3 and Figure 4 The same as in; on the basis of all the nominal kinematic parameters of the robot arm, errors are randomly added, among which the length parameter error does not exceed 120 mm and the angle parameter error does not exceed 9°. All the kinematic parameters of the robot arm are called actual kinematic parameters; the actual kinematic parameters are used to generate the end pose data of the corresponding robot arm in different configurations.

[0170] In order to verify and compare the effects of the implementation methods of the present invention (hereinafter referred to as the "proposed method"), a comparative experiment is required; because only obtaining the kinematic parameter errors of the macro and micro robotic arms separately in the separated working state cannot fully obtain the kinematic parameter errors of the macro and micro robotic arms, the kinematic parameter acquisition method compared here is: directly obtaining the kinematic parameters of the macro and micro robotic arms in the series working state as a whole (hereinafter referred to as "direct calibration").

[0171] Among them, the direct calibration process mainly includes:

[0172] Randomly generate for macro-micro robotic arms preset configurations, where n C = 14 is the degree of freedom of the macro-micro manipulator; the sensor is used to collect the target end position of the manipulator in these preset configurations to obtain the fourth end position, using the homogeneous transformation matrix The target end position is recorded in the form of; for each preset configuration of the macro-micro manipulator, combined with the nominal kinematic parameter KP C nominal Calculate the differential motion vector and the error Jacobian matrix J gL i , solve the kinematic parameter error Based on this, the kinematic parameters KP of the macro-micromanipulator are adjusted iteratively. C nominal Get the final kinematic parameters KP of the macro-micromanipulator L calibrated .

[0173] After comparing the proposed method with the kinematic parameters obtained by direct calibration in the simulation, the terminal posture errors of the macro-micro manipulator in various configurations and the probability cumulative distribution curve of the terminal position error are shown in Figure 2. Figure 6 As shown, assuming Figure 6 There is a point (x, y) on the curve, which indicates that the probability that the 2-norm of the position error is less than or equal to x mm is y; the probability cumulative distribution curve of the terminal attitude error is as follows Figure 7 As shown, assuming Figure 7 There is a point (x, y) on the middle curve, which indicates that the probability that the 2-norm of the position error is less than or equal to x mm is y; that is, Figure 6 and Figure 7In the figure, the closer the point on the curve is to the vertical axis at the same vertical coordinate, the smaller the error. The results show that both methods can significantly reduce the error of the end of the macro-micro manipulator, and the proposed method is effective in improving the positioning accuracy of the end of the macro-micro manipulator.

[0174] After applying the proposed method and directly calibrating the kinematic parameters in the simulation, the error between the obtained kinematic parameters and the actual kinematic parameters is compared. For each parameter in the kinematic model of the macro-micromanipulator, if the absolute value of the difference between the value of the kinematic parameter a obtained by the proposed method or direct calibration and the corresponding value of a in the actual kinematic parameter is z, then a point with a coordinate value of z is drawn at the mark "a" in the figure; the distribution of the length parameter error is obtained as shown in Figure 8 As shown in Figure 2, the distribution of angle parameter errors is as follows: Fig. 9 As shown in the figure, for the same type of parameters (such as parameter a), the smaller the coordinate value of a point is, the more accurate the acquisition result of the corresponding parameter of the point is. From the results, the maximum length parameter error of the parameters obtained by the direct method compared with the actual kinematic parameters is 1.22775mm, and the maximum angle parameter error is 2.06246°; after applying the technical solution of the embodiment of the present invention, the maximum length and angle parameter errors are 2.2204×10 -12 mm and 2.8329×10 -14 °, the kinematic parameters obtained by the embodiment of the present invention are significantly smaller in terms of length and angle errors.

[0175] By comparing the time required for numerical calculations in the simulation environment, the configuration number multiplier p is increased from 1 to 1000. It can be seen from Table 1 that compared with direct calibration, the time consumption of numerical calculations of the technical solution of the embodiment of the present invention is always smaller. When the multiplier p reaches 1000, the time consumption is 0.6907 times that of direct calibration.

[0176] Table 1 Comparison of the computational time of parameter acquisition provided by the embodiment of the present invention and the computational time of direct calibration

[0177]

[0178] The technical solution of the embodiment of the present invention has the following beneficial effects.

[0179] Compared with the existing method of directly obtaining kinematic parameters by treating the macro-micro robotic arm in series working state as a whole:

[0180] a. The iterative error solution algorithm directly involves lower degrees of freedom, lower degree of kinematic parameter coupling, and the obtained kinematic parameters are significantly more accurate;

[0181] b. The number of trigonometric function operations is reduced during the solution process, and the total time consumed for numerical operations is shorter;

[0182] c. The macro-manipulator and the micro-manipulator can collect the target end poses under most preset configurations in parallel to improve the collection efficiency;

[0183] d. A method for obtaining local kinematic parameters is given. When the macro-micro robotic arm is separated and reconnected in series, only a small number of target end poses under preset configurations need to be collected to calculate the local kinematic parameter errors and make adjustments to make the kinematic model of the entire macro-micro robotic arm accurate again, without the need to collect a large number of target end poses under preset configurations to recalculate the kinematic parameter errors of the entire macro-micro robotic arm.

[0184] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0185] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for obtaining parameters of a robotic arm, characterized in that: The method comprises: According to the working state of the robotic arm, the target end position of the robotic arm when it is in a plurality of different preset configurations is collected by using sensors; wherein the robotic arm includes a macro robotic arm and a micro robotic arm, and the working state of the robotic arm includes the macro robotic arm and the micro robotic arm being separated into two robotic arms, or the macro robotic arm and the micro robotic arm being connected in series into a macro-micro robotic arm, and the preset configuration represents the joint angle that can be actually reached by the macro robotic arm, the micro robotic arm, or the macro-micro robotic arm; According to the target end poses collected in two working states of the robot arm respectively, the kinematic parameters of the working state in which the macro robot arm and the micro robot arm are connected in series into one macro-micro robot arm are adjusted to obtain the final kinematic parameters of the macro-micro robot arm.

2. The method according to claim 1, characterized in that According to the working state of the robot arm, sensors are used to collect the target end position when the robot arm is in multiple different preset configurations, including: In a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, when the macro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a first end position of the macro-mechanical arm when it is in each preset configuration, and when the micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a second end position of the micro-mechanical arm when it is in each preset configuration, and the first end position and the second end position are used as target end positions; When the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-micro-robotic arm, when the macro-micro-robotic arm moves to multiple different preset configurations, the sensor is used to collect the third end position of the macro-micro-robotic arm in each preset configuration, and the third end position is used as the target end position.

3. The method according to claim 1, characterized in that According to the target end poses collected in the two working states of the robot arm respectively, the kinematic parameters of the working state of the macro robot arm and the micro robot arm connected in series as a macro-micro robot arm are adjusted to obtain the final kinematic parameters of the macro-micro robot arm, including: For a working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, iteratively calculating errors of all kinematic parameters of the macro-robotic arm according to the acquired first end pose, and adjusting the kinematic parameters of the macro-robotic arm according to the errors; For a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, iteratively calculating errors of all kinematic parameters of the micro-mechanical arm according to the acquired second end posture, and adjusting the kinematic parameters of the micro-mechanical arm according to the errors; According to the adjusted kinematic parameters of the macro-micro robotic arm and the adjusted kinematic parameters of the micro-robotic arm, the shared kinematic parameters of the macro-micro robotic arm are replaced; for the working state in which the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, according to the collected third end posture, iteratively calculate the errors of all kinematic parameters of the micro-robotic arm, and, according to the errors, adjust the differential kinematic parameters of the macro-micro robotic arm to obtain the final kinematic parameters of the macro-micro robotic arm; wherein the shared kinematic parameters are kinematic parameters that belong to the working state in which the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-micro robotic arm, and also exist in the working state in which the macro-robotic arm and the micro-robotic arm are separated into two robotic arms; the differential kinematic parameters are kinematic parameters that belong to the working state in which the macro-robotic arm and the micro-robotic arm are connected in series to form a macro-micro robotic arm, but are not kinematic parameters of the shared kinematic parameters.

4. The method according to claim 2, characterized in that: In a working state where the macro-manipulator and the micro-manipulator are separated into two manipulators, when the macro-manipulator moves to a plurality of different preset configurations, a sensor is used to collect a first end position of the macro-manipulator in each preset configuration, including: Randomly generated for the macro robot preset configurations, where Indicates rounding up, n L represents the degree of freedom of the macro robot, p is a positive number; The sensors are used to collect the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator when the macro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-manipulator relative to the base of the macro-manipulator. The position and posture are recorded in the form of to obtain the first terminal posture.

5. The method according to claim 2, characterized in that: In a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, when the micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a second end position of the micro-mechanical arm in each preset configuration, including: Randomly generate for micro-robotic arms preset configurations, where n S represents the degrees of freedom of the micro-manipulator; The sensors are used to collect the position and posture of the end of the micro-manipulator relative to the micro-manipulator base when the micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the micro-manipulator relative to the micro-manipulator base. The position and posture are recorded in the form of to obtain the second terminal posture.

6. The method according to claim 2, characterized in that In a working state where the macro-mechanical arm and the micro-mechanical arm are connected in series to form a macro-micro-mechanical arm, when the macro-micro-mechanical arm moves to a plurality of different preset configurations, a sensor is used to collect a third end position of the macro-micro-mechanical arm in each preset configuration, including: Randomly generate for the macro-micro robot preset configurations, n' C is the number of coordinate systems with different kinematic parameters; The sensors are used to collect the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator when the macro-micro-manipulator moves to multiple different preset configurations, and the homogeneous transformation matrix is ​​used to calculate the position and posture of the end of the macro-micro-manipulator relative to the base of the macro-micro-manipulator. The position and posture are recorded in the form of to obtain the third terminal posture.

7. The method according to claim 3, characterized in that For a working state where the macro-robotic arm and the micro-robotic arm are separated into two robotic arms, iteratively calculating errors of all kinematic parameters of the macro-robotic arm according to the acquired first end pose, and adjusting the kinematic parameters of the macro-robotic arm according to the errors, including: In each iteration, for each preset configuration of the macro robot, the nominal kinematic parameter KP Lnominal , and based on the forward kinematics algorithm, calculate the nominal end pose According to the nominal end position The first end position acquired Get the antisymmetric matrix: Among them, d x d y d z They represent the moving distance along the x, y, and z axes in the terminal coordinate system, respectively. x ,δ y ,δ z Respectively represent the rotation angles around the x, y, and z axes in the terminal coordinate system; Convert the antisymmetric matrix into a differential motion vector In the form of: Among them, ∨ is the operator that converts the antisymmetric matrix into a differential motion vector; According to the nominal kinematic parameter KP Lnominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gLi : This gives a system of equations in matrix form: in, To all The matrix obtained by combining in column form is, For all J gLi The matrix obtained by combining in column form is, is the error of all kinematic parameters of the macro robot, Contains (q·(n L +1)) components; Find the equation Solution in the least squares sense: in, + represents pseudo-inverse; Adjust the nominal kinematic parameters of the macro robot: until When each component in is less than the preset threshold, the KP obtained in the last iteration is Lnominal As the kinematic parameter KP of the adjusted macro robot Lcalibrated .

8. The method according to claim 3, characterized in that For a working state where the macro-mechanical arm and the micro-mechanical arm are separated into two mechanical arms, iteratively calculating errors of all kinematic parameters of the micro-mechanical arm according to the acquired second end posture, and adjusting the kinematic parameters of the micro-mechanical arm according to the errors, including: In each iteration, for each preset configuration of the micromanipulator, the nominal kinematic parameter KP Snominal , and based on the forward kinematics algorithm, calculate the nominal end pose According to the nominal end position The second end position acquired Get the antisymmetric matrix: Convert the antisymmetric matrix into a differential motion vector In the form of: According to the nominal kinematic parameters KP of the micromanipulator Snominal , and based on the mapping relationship between the errors of all kinematic parameters and the end pose errors, the error Jacobian matrix J is calculated gSi : This gives a system of equations in matrix form: in, To all The matrix obtained by combining in column form is, For all J gSi The matrix obtained by combining in column form is, is the error of all kinematic parameters of the micromanipulator, Contains (q·(n S +1)) components; Find the equation Solution in the least squares sense: Adjust the nominal kinematic parameters of the micromanipulator: until When each component in is less than the preset threshold, the KP obtained in the last iteration is Snominal As the kinematic parameter KP of the adjusted micromanipulator Scalibrated .

9. The method according to claim 3, characterized in that: According to the adjusted kinematic parameters of the macro-mechanical arm and the adjusted kinematic parameters of the micro-mechanical arm, the common kinematic parameters of the macro-micro-mechanical arm are replaced, and, according to the collected third end posture, the differential kinematic parameters of the macro-micro-mechanical arm are adjusted to obtain the final kinematic parameters of the macro-micro-mechanical arm, including: For the working state where the macro-mechanical arm and the micro-mechanical arm are connected in series to form a macro-micro-mechanical arm, for each parameter element in the kinematic parameters shared by the macro-micro-mechanical arm, if the parameter element exists in the macro-mechanical arm, it is changed to be the same as the corresponding parameter element in the kinematic parameters of the macro-mechanical arm after adjustment; if the parameter element exists in the micro-mechanical arm, it is changed to be the same as the corresponding parameter element in the kinematic parameters of the micro-mechanical arm after adjustment; According to the third terminal pose acquired, iteratively calculate the errors of all kinematic parameters of the micro-mechanical arm, and adjust the differential kinematic parameters of the macro-micro-mechanical arm according to the errors. In each iteration, for each preset configuration of the macro-micro-mechanical arm, according to the nominal kinematic parameters KP Cnominal , and based on the forward kinematics algorithm, calculate the nominal end pose According to the nominal end position The third end position of the acquisition Get the antisymmetric matrix: Convert the antisymmetric matrix into a differential motion vector In the form of: According to the nominal kinematic parameter KP Cnominal , and based on the mapping relationship between the error of the difference kinematic parameters and the end posture error, the error Jacobian matrix J′ corresponding to the difference kinematic parameters is calculated gCi : Among them, KP′ Cnominal are the nominal differential kinematic parameters; This gives a system of equations in matrix form: in, To all The matrix is ​​combined in column form, where To convert all J′ gCi The matrix obtained by combining in column form is, is the error of the difference kinematic parameters, Contains (q·n′ C ) portions; Find the equation Solution in the least squares sense: Adjust the differential kinematic parameters of the macro-micro manipulator: until When each component in is less than the preset threshold, the KP′ obtained in the last iteration is used Cnominal Replace KP Cnominal The difference kinematic parameters in the adjusted macro-micromanipulator are obtained by Ccalibrated , as the final kinematic parameters of the macro-micro robotic arm.

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