Five-axis robot configuration comprehensive method integrating 2R1T parallel mechanism

Abstract

The invention discloses a five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism, and belongs to the technical field of robot manufacturing. A two-rotation and one-translation (2R1T) parallel mechanism is a core function module of a five-axis robot, most of the 2R1T parallel mechanisms are parallel mechanisms formed by connecting a plurality of kinematic pairs (such as an R pair, an S pair, a P pair, a U pair and a C pair) in series to form a kinematic branch chain and connecting a plurality of kinematic branch chains in parallel, the two ends of the kinematic branch chain are connected with a static platform and a movable platform respectively, calculation is carried out based on a PRU type kinematic branch chain, and the two-rotation and one-translation (2R1T) parallel mechanism is formed. A series of 2R1T parallel mechanism topological configurations are obtained through the spiral theory, a 2R1T parallel mechanism motion spiral system is analyzed, the 2R1T parallel mechanism and the single-degree-of-freedom joint module are reasonably configured, and it is ensured that the five-axis robot has the motion performance meeting the working requirement.

Description

Technical Field

[0001] This invention relates to the technical field of robot configuration, and in particular to a method for integrating a 2R1T parallel mechanism into a five-axis robot configuration. Background Technology

[0002] Five-axis robots combine the advantages of parallel mechanisms (high stability, high rigidity, and high speed) with the advantages of serial mechanisms (expanding workspace), further expanding their application potential in the efficient machining of large and complex structural parts. Among them, the 2R1T parallel mechanism is a three-degree-of-freedom parallel mechanism with one translational degree of freedom and two rotational degrees of freedom. It has the advantages of high rigidity, strong load capacity, and high motion accuracy. The commercially successful five-axis hybrid machining robots Eco-speed, Tricept, and Exechon all use the 2R1T parallel mechanism as their core functional module.

[0003] The configuration synthesis of a five-axis robot involves two crucial aspects: the design of parallel mechanisms and the selection of serial single-DOF joint modules and parallel mechanisms. Both are indispensable. Currently, most scholars only study the configuration synthesis method of the 2R1T parallel mechanism, neglecting the selection of serial single-DOF joint modules, thus failing to guide the entire configuration design process of a five-axis robot. The motion performance of a five-axis robot is highly dependent on the matching and spatial layout of serial and parallel mechanism modules. The single-DOF joint modules of a five-axis robot complement the motion capabilities of the 2R1T parallel mechanism, together forming a five-axis robot with good motion performance. Improper selection of single-DOF joint modules can lead to a small workspace, failing to achieve the expected kinematic performance of the five-axis robot. However, research on the overall configuration synthesis method for five-axis robots is still relatively lacking, with only a few scholars conducting research. For example, Yundou Xu performed type synthesis and motion decoupling on the 2R1T parallel mechanism and proposed a five-axis robot construction principle based on motion decoupling, but his paper did not mention a complete five-axis robot configuration selection scheme. Summary of the Invention

[0004] The purpose of this invention is to provide a method for integrating a 2R1T parallel mechanism into a five-axis robot configuration. By using spiral theory, a series of 2R1T parallel mechanism topologies are obtained, and the motion spiral system of the 2R1T parallel mechanism is analyzed. The 2R1T parallel mechanism and single-degree-of-freedom joint modules are rationally configured to ensure that the five-axis robot has the required motion performance.

[0005] To achieve the above objectives, this invention provides a method for integrating a 2R1T parallel mechanism into a five-axis robot configuration, comprising the following steps: Step 1: For a five-axis robot, the components include a 2R1T parallel mechanism, a single-degree-of-freedom joint module, a tool, a fixture, and a frame. For the 2R1T parallel mechanism, a "PRU" type kinematic chain is selected to conduct a comprehensive study of the 2R1T parallel mechanism configuration. The "PRU" type kinematic chain refers to a type of kinematic chain with configurations of PUR, PRU, UPR, URP, RPU, and RUP, where P represents a prismatic joint, R represents a revolute joint, and U represents a Hooke joint. Step 2: The 2R1T parallel mechanism composed of the "PRU" kinematic branches is used to synthesize a series of potential configurations. The potential configurations of the 2R1T parallel mechanism are classified into three types according to the distribution of the rotation axis: UP, PU, ​​and RPR. Step 3: For the specific functions that the five-axis robot needs to achieve, set up a 2R1T parallel mechanism and a single-degree-of-freedom joint module, select the corresponding different types of configurations and combine them to obtain the configuration synthesis result; Step 4: Based on the actual working requirements of the five-axis robot, select the corresponding combination from the configuration synthesis results to obtain the configuration design of the five-axis robot with the 2R1T parallel mechanism.

[0006] Preferably, in step one, for the 2R1T parallel mechanism, the calculation process for selecting the "PRU" type kinematic branch to calculate the configuration of the 2R1T parallel mechanism is as follows: According to spinor theory, the spinor system of the "PRU" type kinematic branch is obtained: ; In the above formula, , , , These represent the axes of the prismatic joint, the rotational joint, and the Hooke's joint, respectively. ; , , , Let represent the unit direction vectors at the axes of the prismatic joint, the rotational joint, and the two joint axes of the Hooke's joint, respectively. and Let represent the position vectors of the geometric centers of the rotational joint and the Hooke's joint, respectively. Both these vectors and the screws are measured in branched coordinates. By reversing the rotation of the motion screw, we obtain its constraint screw system as follows: ; In the above formula, Indicates a value that is simultaneously perpendicular to and The constraint force couple spin; Indicates a pass Any point on the axis that is parallel to it. The constraint spinor; It has been expressed The position vector of any point on the axis; to construct a redundant driven parallel operating head using a few-degree-of-freedom motion chain, it is necessary to explore the geometric conditions for forming equivalent constraints between the two motion chains, ensuring that the constraint screws introduced by the new chain are linearly related to the original constraint screw system; therefore, according to screw theory, when the constraint force screws and constraint force couple screws of the two motion chains are equal, the constraint screws of the two "PRU" type motion chains satisfy the following formula: ; In the above formula, The constraint couple spin of the first "PRU" kinematic branch is represented as follows. The constraint couple spin of the second "PRU" kinematic branch is represented as follows. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the second "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the second "PRU" kinematic branch. This is represented as the constraint spinor of the first "PRU" kinematic branch. The constraint spinor of the second "PRU" kinematic branch is represented as follows. This is represented as the unit direction vector of the first "PRU" kinematic link revolute joint. This indicates that it is past. The position vector of any point on the axis. This is represented as the unit direction vector of the revolute joint of the second "PRU" kinematic chain. This indicates that it is past. Given the position vector of any point on the axis, the following formula is derived: ; According to the above formula, the geometric condition for achieving equality of both the constraint force couple spin and the constraint force spin between two "PRU" type kinematic branches is stated as follows: the axis of the revolute joint in the two branches and Parallel to each other; the second axis of the Hooke's hinge in the two branches and Collinear; two "PRU" kinematic branches arranged according to geometric conditions are called a 2'PRU' mechanism, and its constraint spinor system is as follows: ; In the above formula, , These represent the first and second constraint spinors of the 2'PRU' mechanism, respectively. and This represents the unit direction vector of the first and second axes of the Hooke's hinge; The unit direction vector representing the axis of rotation of the joint; Let the position vector of any point on the second axis of the Hooke hinge be represented, and then reverse the spiral to obtain the motion spiral system of the 2'PRU' mechanism: ; In the above formula, , , and Let represent the 1st, 2nd, 3rd, and 4th motion screws in the 2'PRU' mechanism, respectively. From the above analysis, a single 2'PRU' mechanism already generates one constraint force and one constraint couple. The 2R1T mechanism has two rotational degrees of freedom and one translational degree of freedom. Therefore, motion chains other than the 2'PRU' mechanism can only generate one constraint force. According to the motion screw system of the 2RU mechanism, the 2'PRU' mechanism loses its constraint couple after introducing a zero-pitch motion screw that is not coplanar with either axis of the Hooke's joint. This mechanism is called the (2'PRU')R mechanism. Therefore, only one constraint force exists in the (2'PRU')R mechanism. An additional revolute joint is introduced at the end of the 2'PRU mechanism. The axis of this revolute joint is perpendicular to and intersects the second axis of the Hooke's joint in the "PRU" type motion chain. The motion screw of the introduced revolute joint is expressed as follows: ; In the above formula, The unit direction vector of the new revolute joint; Let the position vector of the intersection point between the new revolute joint axis and the second axis of the Hooke's joint be represented. The formula for the kinematic screw system of the (2'PRU')R mechanism is as follows: ; By taking the reverse screw of the motion screw system of the (2'PRU')R mechanism, we obtain the constraint screw system of the (2'PRU')R mechanism: ; Thus, the maximum linearly independent constraint spinor system of the parallel mechanism composed of the 2'PRU' mechanism and the (2'PRU')R mechanism is obtained as follows: ; In the above formula, , , These represent the 1st, 2nd, and 3rd independent constraint spinors, respectively. , and Let represent the unit direction vectors of the revolute joint axis, the first axis of the Hooke's joint, and the second axis, respectively; Let the unit direction vector of the axis of rotation of the (2'PRU')R mechanism be represented. Then, by performing a reverse screw solution on the maximum linearly independent constraint screw system, the motion screws of the parallel mechanism are obtained: ; In the above formula, Represents a degree of freedom of movement, perpendicular to and ; This represents a rotational degree of freedom, with the axis of rotation parallel to... And it passes through point O; This represents a rotational degree of freedom, with the axis of rotation parallel to... Furthermore, the rotational property of the parallel mechanism passing through point O indicates that the 2'PRU' mechanism and the (2'PRU')R mechanism form a 2R1T parallel mechanism, which has two rotation axes. One rotation axis is close to the Hooke's joint of the 2'PRU' mechanism, and the other rotation axis is close to the Hooke's joint of the (2'PRU')R mechanism. This leads to the calculation of several types of 2R1T parallel mechanisms.

[0007] Preferably, in step two, the configurations of the 2R1T parallel mechanism are classified according to the distribution position of the rotating shafts: the UP type has both rotating shafts close to the stationary platform, the PU type has both rotating shafts close to the moving platform, and the RPR type has one rotating shaft close to the stationary platform and one rotating shaft close to the moving platform.

[0008] Preferably, in step three, the types of configurations for the 2R1T parallel mechanism and single-degree-of-freedom joint module, for the functions to be achieved by the five-axis robot, include the following: The 2R1T parallel mechanism in a five-axis robot is divided into three types according to its function: two attitude adjustments + one position adjustment, one attitude adjustment + two position adjustments, and three position adjustments. Based on the different functions of the 2R1T parallel mechanism, the serial single-degree-of-freedom joint module in a five-axis robot is divided into two position adjustments, one attitude adjustment + one position adjustment, and two attitude adjustments.

[0009] Preferably, in step three, different types of configurations are selected and combined. The topological configurations of the five-axis robot are divided into the following three combinations: Case 1: The two rotating axes of the 2R1T parallel mechanism are both close to the moving platform. The functions of the 2R1T parallel mechanism are 1. Position adjustment and 2. Attitude adjustment. It requires two single-degree-of-freedom joint modules for position adjustment to be connected in series. This configuration is defined as the double position adjustment type, corresponding to the PU type in the 2R1T parallel mechanism configuration. Case 2: The two rotation axes of the 2R1T parallel mechanism are both close to the stationary platform. The function of the 2R1T parallel mechanism is 3-position adjustment. It requires two single-degree-of-freedom joint modules for attitude adjustment to be connected in series. This configuration is defined as the double attitude adjustment type, which corresponds to the UP type in the configuration of the 2R1T parallel mechanism. Scenario 3: In a 2R1T parallel mechanism, one rotation axis is close to the moving platform, and the other rotation axis is close to the stationary platform. The 2R1T parallel mechanism is a 2-position adjustment and 1-attitude adjustment mechanism. It requires one single-degree-of-freedom joint module for position adjustment and one single-degree-of-freedom joint module for attitude adjustment to be connected in series. This configuration is defined as a one-attitude adjustment and one-position adjustment type, corresponding to the RPR type in the 2R1T parallel mechanism configuration. Different combinations are selected according to the situation to achieve the corresponding required functions.

[0010] Therefore, the present invention employs the above-described method for synthesizing a five-axis robot configuration integrating a 2R1T parallel mechanism, which has the following advantages: (1) In this invention, the topological configurations of three types of 2R1T parallel mechanisms are synthesized by starting with the "PRU" type motion branch. The main difference between the three types of 2R1T parallel mechanisms is that the rotation axis position is different, which is the premise for constructing five-axis robots with different configurations.

[0011] (2) In this invention, by analyzing the rotation axis distribution of the 2R1T parallel mechanism, analyzing the motion characteristics of the 2R1T parallel mechanism, selecting a suitable single-degree-of-freedom module, and constructing a potential hybrid topology configuration that meets the requirements of the motion feature set, a design method for constructing a five-axis robot configuration is provided to the designer.

[0012] (3) In this invention, it is analyzed how to arrange single-degree-of-freedom joints to ensure that the workspace and 2R3T motion capability of the designed five-axis robot meet the requirements.

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a flowchart illustrating the overall process of a five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism according to the present invention. Figure 2 This is a configuration diagram of a dual-position-adjustment type robot in a five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism according to the present invention; Figure 3 This is a configuration diagram of a dual-attitude-adjusting robot in a five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism according to the present invention. Figure 4 This is a configuration diagram of a posture-adjusting and attitude-adjusting robot in the five-axis robot configuration synthesis method integrating a 2R1T parallel mechanism of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Specific model specifications need to be selected and determined according to the actual specifications of the device, etc. The specific selection calculation method adopts existing technology in the art, and therefore will not be described in detail.

[0016] Example like Figure 1 As shown, this invention provides a method for integrating a 2R1T parallel mechanism into a five-axis robot configuration, comprising the following steps: Step 1: For a five-axis robot, the components include a 2R1T parallel mechanism, a single-DOF joint module, a tool, a fixture, and a frame. For the 2R1T parallel mechanism, a "PRU" type kinematic chain is selected for configuration synthesis. A "PRU" type kinematic chain refers to a class of kinematic chains with configurations such as PUR, "PRU", UPR, URP, RPU, and RUP, where P represents a prismatic joint, R represents a revolute joint, and U represents a Hooke joint. The specific calculation process is as follows: According to spinor theory, the spinor system of the "PRU" type kinematic branch is obtained: ; In the above formula, , , , These represent the axes of the prismatic joint, the rotational joint, and the Hooke's joint, respectively. ; , , , Let represent the unit direction vectors at the axes of the prismatic joint, the rotational joint, and the two joint axes of the Hooke's joint, respectively. and Let represent the position vectors of the geometric centers of the rotational joint and the Hooke's joint, respectively. Both these vectors and the screws are measured in branched coordinates. By reversing the rotation of the motion screw, we obtain its constraint screw system as follows: ; In the above formula, Indicates a value that is simultaneously perpendicular to and The constraint force couple spin; Indicates a pass Any point on the axis that is parallel to it. The constraint spinor; It has been expressed The position vector of any point on the axis; According to screw theory, a 2R1T parallel mechanism has only three degrees of freedom, and its constraint screws should also have only three. In the assembly of motion branches in redundant parallel mechanisms, there are two main ways to avoid introducing linearly independent constraints into the system: one is to ensure that the constraint screws introduced by the new branch are linearly related to the original constraint screw system, thus forming equivalent constraints; the other is to use a six-degree-of-freedom unconstrained motion branch that does not impose any constraints itself. However, a "PRU" type motion branch has two constraint screws. To construct a 2R1T parallel mechanism using this motion branch, it is necessary to study the geometric conditions under which the two motion branches form equivalent constraints. When the constraint force screws and constraint couple screws of the two motion branches are equal, there is greater potential for constructing a fully symmetric 2R1T parallel mechanism. When the constraint force screws and constraint couple screws of the two motion branches are equal, the constraint screws of the two "PRU" type motion branches satisfy the following formula: ; In the above formula, The constraint couple spin of the first "PRU" kinematic branch is represented as follows. The constraint couple spin of the second "PRU" kinematic branch is represented as follows. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the second "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the second "PRU" kinematic branch. This is represented as the constraint spinor of the first "PRU" kinematic branch. The constraint spinor of the second "PRU" kinematic branch is represented as follows. This is represented as the unit direction vector of the first "PRU" kinematic link revolute joint. This indicates that it is past. The position vector of any point on the axis. This is represented as the unit direction vector of the revolute joint of the second "PRU" kinematic chain. This indicates that it is past. Given the position vector of any point on the axis, the following formula is derived: ; According to the above formula, the geometric condition for achieving equality of both the constraint force couple spin and the constraint force spin between two "PRU" type kinematic branches is stated as follows: the axis of the revolute joint in the two branches and Parallel to each other; the second axis of the Hooke's hinge in the two branches and Collinear; two "PRU" kinematic branches arranged according to geometric conditions are called a 2'PRU' mechanism, and its constraint spinor system is as follows: ; In the above formula, , These represent the first and second constraint spinors of the 2'PRU' mechanism, respectively. and This represents the unit direction vector of the first and second axes of the Hooke's hinge; The unit direction vector representing the axis of rotation of the joint; Let the position vector of any point on the second axis of the Hooke hinge be represented, and then reverse the spiral to obtain the motion spiral system of the 2'PRU' mechanism: ; In the above formula, , , and Let represent the 1st, 2nd, 3rd, and 4th motion screws in the 2'PRU' mechanism, respectively. From the above analysis, a single 2'PRU' mechanism already generates one constraint force and one constraint couple. The 2R1T mechanism has two rotational degrees of freedom and one translational degree of freedom. Therefore, motion chains other than the 2'PRU' mechanism can only generate one constraint force. According to the motion screw system of the 2RU mechanism, the 2'PRU' mechanism loses its constraint couple after introducing a zero-pitch motion screw that is not coplanar with either axis of the Hooke's joint. This mechanism is called the (2'PRU')R mechanism. Therefore, only one constraint force exists in the (2'PRU')R mechanism. An additional revolute joint is introduced at the end of the 2'PRU mechanism. The axis of this revolute joint is perpendicular to and intersects the second axis of the Hooke's joint in the "PRU" type motion chain. The motion screw of the introduced revolute joint is expressed as follows: ; In the above formula, The unit direction vector of the new revolute joint; Let the position vector of the intersection point between the new revolute joint axis and the second axis of the Hooke's joint be represented. The formula for the kinematic screw system of the (2'PRU')R mechanism is as follows: ; By taking the reverse screw of the motion screw system of the (2'PRU')R mechanism, we obtain the constraint screw system of the (2'PRU')R mechanism: ; Thus, the maximum linearly independent constraint spinor system of the parallel mechanism composed of the 2'PRU' mechanism and the (2'PRU')R mechanism is obtained as follows: ; In the above formula, , , These represent the 1st, 2nd, and 3rd independent constraint spinors, respectively. , and Let represent the unit direction vectors of the revolute joint axis, the first axis of the Hooke's joint, and the second axis, respectively; Let the unit direction vector of the axis of rotation of the (2'PRU')R mechanism be represented. Then, by performing a reverse screw solution on the maximum linearly independent constraint screw system, the motion screws of the parallel mechanism are obtained: ; In the above formula, Represents a degree of freedom of movement, perpendicular to and ; This represents a rotational degree of freedom, with the axis of rotation parallel to... And it passes through point O; This represents a rotational degree of freedom, with the axis of rotation parallel to... Furthermore, the rotational property of the parallel mechanism passing through point O indicates that the 2'PRU' mechanism and the (2'PRU')R mechanism form a 2R1T parallel mechanism, which has two rotational axes. One rotational axis is close to the Hooke's joint of the 2'PRU' mechanism, and the other rotational axis is close to the Hooke's joint of the (2'PRU')R mechanism. Several 2R1T parallel mechanisms can then be calculated. The configurations obtained from the actual calculations are shown in Table 1 below: Table 1 Topology of 2R1T Parallel Mechanism

[0017] The magnitude of the entrainment motion caused by the rotational motion of the 2R1T parallel mechanism is related to the distance from the rotating axis to the moving platform. The farther the rotating axis is from the moving platform, the greater the entrainment motion; the closer the rotating axis is to the moving platform, the smaller the entrainment motion. Under the constraint of a fixed five-axis robot footprint, when the rotating axis is not on the moving platform, rotation will result in significant movement, leading to a decrease in the end effector's attitude adjustment capability. Based on the entrainment motion, the following definition is given: when the footprint of the five-axis hybrid robot is determined, a rotating axis position closer to the stationary platform is suitable for position adjustment, and conversely, a rotating axis position closer to the stationary platform is suitable for attitude adjustment.

[0018] Step 2: Classify the configuration of the 2R1T parallel mechanism according to the distribution of the rotating shafts. There are three types: UP, PU, ​​and RPR. P represents a sliding joint, R represents a rotary joint, and U represents a Hooke joint. In the UP type, both rotating shafts are close to the stationary platform. In the PU type, both rotating shafts are close to the moving platform. In the RPR type, one rotating shaft is close to the stationary platform and the other rotating shaft is close to the moving platform.

[0019] Step 3: To achieve the desired functions of the five-axis robot, a 2R1T parallel mechanism and a single-degree-of-freedom joint module are set up. Different types of configurations are selected and combined to obtain the overall configuration result, as follows: The 2R1T parallel mechanism in a five-axis robot is divided into three types according to its function: two attitude adjustments + one position adjustment, one attitude adjustment + two position adjustments, and three position adjustments. Based on the different functions of the 2R1T parallel mechanism, the serial single-degree-of-freedom joint module in a five-axis robot is divided into two position adjustments, one attitude adjustment + one position adjustment, and two attitude adjustments.

[0020] In step three, different types of configurations are selected and combined. The topological configurations of the five-axis robot are divided into the following three combinations: Case 1: The two rotating axes of the 2R1T parallel mechanism are both close to the moving platform. The functions of the 2R1T parallel mechanism are 1. Position adjustment and 2. Attitude adjustment. It requires two single-degree-of-freedom joints for position adjustment to be connected in series. This configuration is defined as the double position adjustment type, corresponding to the PU type in the 2R1T parallel mechanism configuration. Case 2: The two rotation axes of the 2R1T parallel mechanism are both close to the stationary platform. The function of the 2R1T parallel mechanism is 3-position adjustment, which requires two single-degree-of-freedom joints for attitude adjustment to be connected in series. This configuration is defined as the double attitude adjustment type, corresponding to the UP type in the configuration of the 2R1T parallel mechanism. Scenario 3: In a 2R1T parallel mechanism, one rotation axis is close to the moving platform, and the other rotation axis is close to the stationary platform. The 2R1T parallel mechanism is a 2-position adjustment and 1-attitude adjustment mechanism. It requires one single-degree-of-freedom joint for position adjustment and one single-degree-of-freedom joint for attitude adjustment to be connected in series. This configuration is defined as a one-attitude adjustment and one-position adjustment type, corresponding to the RPR type in the 2R1T parallel mechanism configuration. Different combinations are selected according to the situation to achieve the corresponding required functions.

[0021] The topological configurations for actual combinations are shown in Table 2 below: Table 2 Topology of Five-Axis Robots

[0022] Step 4: Based on the actual situation, select the corresponding combination from the configuration synthesis results to obtain the configuration design of the five-axis robot with 2R1T parallel mechanism.

[0023] This section provides an example, selecting a five-axis milling robot as the research object from the specific types of five-axis robots. It calculates the configuration combinations of the five-axis milling robot and provides examples of different configuration combinations, such as... Figures 2 to 4 As shown: like Figure 2 As shown, for the double-adjustable type: ① Two rotary joints are connected in series, with the rotation axis of the rotational degree of freedom located on the stationary platform; ② Two traversable joints are connected in series, with the traversable joints located between the 2R1T parallel mechanism and the tool, between the machine tool and the 2R1T parallel mechanism, or between the machine tool and the fixture; ③ One rotary joint and one traversable joint are connected in series, with the rotary joint located on the stationary platform, and the traversable joint located between the 2R1T parallel mechanism and the tool or between the machine tool and the fixture. In the figure, R represents the rotary joint, PM represents the 2R1T parallel mechanism, ST represents the tool, WP represents the fixture, and FB represents the frame. like Figure 3 As shown, for the double-adjustable type: only two rotary joints can be connected in series in this case. Their positions can be between the 2R1T parallel mechanism and the tool or between the machine tool and the fixture. In the figure, R represents the rotary joint, PM represents the 2R1T parallel mechanism, ST represents the tool, WP represents the fixture, and FB represents the frame.

[0024] like Figure 4 As shown, for a one-position-adjustment type: ① Two rotary joints are connected in series. One rotary joint's rotation axis is located on the stationary platform for position adjustment, and the other rotary joint can be arranged between the 2R1T parallel mechanism and the tool, or between the machine tool and the fixture, for posture adjustment. ② One rotary joint and one traverse joint are connected in series. The rotary joint can be arranged between the 2R1T parallel mechanism and the tool, or between the machine tool and the fixture, for posture adjustment. The traverse joint can be arranged between the 2R1T parallel mechanism and the tool, between the machine tool and the 2R1T parallel mechanism, or between the machine tool and the fixture, for position adjustment. In the figure, T represents a traverse joint, R represents a rotary joint, PM represents the 2R1T parallel mechanism, ST represents the tool, WP represents the fixture, and FB represents the frame.

[0025] Therefore, this invention employs a five-axis robot configuration synthesis method integrating 2R1T parallel mechanisms. Starting with serial branch analysis, a series of 2R1T parallel mechanisms composed of 2'PRU' and (2'PRU')R' mechanisms are obtained, and a series of topological configurations of 2R1T parallel mechanisms are synthesized. By analyzing the rotation axis positions of the 2R1T parallel mechanisms, based on the entrainment motion, the functions of the 2R1T parallel mechanisms and the functions of the corresponding single-degree-of-freedom modules are determined. Furthermore, based on the determined module functions, the possible positions of the single-degree-of-freedom joints are determined, and all potential topological configurations of the five-axis robot are synthesized.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for synthesizing the configuration of a five-axis robot integrating a 2R1T parallel mechanism, characterized in that: Includes the following steps: Step 1: For a five-axis robot, the components include a 2R1T parallel mechanism, a single-degree-of-freedom joint module, a tool, a fixture, and a frame. For the 2R1T parallel mechanism, a "PRU" type kinematic chain is selected to conduct a comprehensive study of the 2R1T parallel mechanism configuration. The "PRU" type kinematic chain refers to a type of kinematic chain with configurations of PUR, PRU, UPR, URP, RPU, and RUP, where P represents a prismatic joint, R represents a revolute joint, and U represents a Hooke joint. Step 2: The 2R1T parallel mechanism composed of the "PRU" kinematic branches is used to synthesize a series of potential configurations. The potential configurations of the 2R1T parallel mechanism are classified into three types according to the distribution of the rotation axis: UP, PU, ​​and RPR. Step 3: For the specific functions that the five-axis robot needs to achieve, set up a 2R1T parallel mechanism and a single-degree-of-freedom joint module, select the corresponding different types of configurations and combine them to obtain the configuration synthesis result; Step 4: Based on the actual working requirements of the five-axis robot, select the corresponding combination from the configuration synthesis results to obtain the configuration design of the five-axis robot with the 2R1T parallel mechanism.

2. The method for integrating a 2R1T parallel mechanism into a five-axis robot configuration according to claim 1, characterized in that: In step one, the calculation process for the configuration of the 2R1T parallel mechanism, using the "PRU" type kinematic branch, is as follows: According to spinor theory, the spinor system of the "PRU" type kinematic branch is obtained: ； In the above formula, , , , These represent the axes of the prismatic joint, the rotational joint, and the Hooke's joint, respectively. ; , , , Let represent the unit direction vectors at the axes of the prismatic joint, the rotational joint, and the two joint axes of the Hooke's joint, respectively. and Let represent the position vectors of the geometric centers of the rotational joint and the Hooke's joint, respectively. Both these vectors and the screws are measured in branched coordinates. By reversing the rotation of the motion screw, we obtain its constraint screw system as follows: ； In the above formula, Indicates a value that is simultaneously perpendicular to and The constraint force couple spin; Indicates a pass Any point on the axis that is parallel to it. The constraint spinor; It has been expressed The position vector of any point on the axis; to construct a redundant driving parallel operating head using a few-degree-of-freedom motion chain, it is necessary to explore the geometric conditions for forming equivalent constraints between the two motion chains, ensuring that the constraint screws introduced by the new chain are linearly related to the original constraint screw system; therefore, according to screw theory, when the constraint force screws and constraint force couple screws of the two motion chains are equal, the constraint screws of the two "PRU" type motion chains satisfy the following formula: ； In the above formula, Let the constraint couple spin of the first "PRU" kinematic branch be represented. This is represented as the spinus of the constraint couple in the second "PRU" kinematic branch. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the first "PRU" kinematic branch. This is represented as the unit direction vector at the first joint of the Hooke's hinge in the second "PRU" kinematic branch. This is represented as the unit direction vector at the second joint of the Hooke's hinge in the second "PRU" kinematic branch. Let the constraint spinor be represented as the first "PRU" kinematic branch. This is represented as the constraint spinor of the second "PRU" kinematic branch. This is represented by the unit direction vector of the first "PRU" kinematic link revolute joint. This indicates that it is past. The position vector of any point on the axis. This is represented as the unit direction vector of the revolute joint of the second "PRU" kinematic chain. This indicates that it is past. Given the position vector of any point on the axis, the following formula is derived: ； According to the above formula, the geometric condition for achieving equality of both the constraint force couple spin and the constraint force spin between two "PRU" type kinematic branches is stated as follows: the axis of the revolute joint in the two branches and Parallel to each other; the second axis of the Hooke's hinge in the two branches and Collinear; two "PRU" kinematic branches arranged according to geometric conditions are called a 2'PRU' mechanism, and its constraint spinor system is as follows: ； In the above formula, , These represent the first and second constraint spinors of the 2'PRU' mechanism, respectively. and This represents the unit direction vector of the first and second axes of the Hooke's hinge; The unit direction vector representing the axis of the revolute joint; Let the position vector of any point on the second axis of the Hooke hinge be represented, and then reverse the spiral to obtain the motion spiral system of the 2'PRU' mechanism: ； In the above formula, , , and Let represent the 1st, 2nd, 3rd, and 4th motion screws in the 2'PRU' mechanism, respectively. From the above analysis, a single 2'PRU' mechanism already generates one constraint force and one constraint couple. The 2R1T mechanism has two rotational degrees of freedom and one translational degree of freedom. Therefore, motion chains other than the 2'PRU' mechanism can only generate one constraint force. According to the motion screw system of the 2RU mechanism, the 2'PRU' mechanism loses its constraint couple after introducing a zero-pitch motion screw that is not coplanar with either axis of the Hooke's joint. This mechanism is called the (2'PRU')R mechanism. Therefore, only one constraint force exists in the (2'PRU')R mechanism. An additional revolute joint is introduced at the end of the 2'PRU mechanism. The axis of this revolute joint is perpendicular to and intersects the second axis of the Hooke's joint in the "PRU" type motion chain. The motion screw of the introduced revolute joint is expressed as follows: ； In the above formula, The unit direction vector of the new revolute joint; Let the position vector of the intersection point between the new revolute joint axis and the second axis of the Hooke's joint be represented. The formula for the kinematic screw system of the (2'PRU')R mechanism is as follows: ； By taking the reverse screw of the motion screw system of the (2'PRU')R mechanism, we obtain the constraint screw system of the (2'PRU')R mechanism: ； Thus, the maximum linearly independent constraint spinor system of the parallel mechanism composed of the 2'PRU' mechanism and the (2'PRU')R mechanism is obtained as follows: ； In the above formula, , , These represent the 1st, 2nd, and 3rd independent constraint spinors, respectively. , and Let represent the unit direction vectors of the revolute joint axis, the first axis of the Hooke's joint, and the second axis, respectively; Let the unit direction vector of the axis of rotation of the (2'PRU')R mechanism be represented. Then, by performing a reverse screw solution on the maximum linearly independent constraint screw system, the motion screws of the parallel mechanism are obtained: ； In the above formula, Represents a degree of freedom of movement, perpendicular to and ; This represents a rotational degree of freedom, with the axis of rotation parallel to... And it passes through point O; This represents a rotational degree of freedom, with the axis of rotation parallel to... Furthermore, the rotational property of the parallel mechanism passing through point O indicates that the 2'PRU' mechanism and the (2'PRU')R mechanism form a 2R1T parallel mechanism, which has two rotation axes. One rotation axis is close to the Hooke's joint of the 2'PRU' mechanism, and the other rotation axis is close to the Hooke's joint of the (2'PRU')R mechanism. This leads to the calculation of several types of 2R1T parallel mechanisms.

3. The method for integrating a 2R1T parallel mechanism into a five-axis robot configuration according to claim 1, characterized in that: In step two, the configurations of the 2R1T parallel mechanism are classified according to the distribution of the rotating shafts. In the UP type, both rotating shafts are close to the stationary platform; in the PU type, both rotating shafts are close to the moving platform; and in the RPR type, one rotating shaft is close to the stationary platform and the other rotating shaft is close to the moving platform.

4. The method for integrating a 2R1T parallel mechanism into a five-axis robot configuration according to claim 3, characterized in that: In step three, the types of configurations for the 2R1T parallel mechanism and single-degree-of-freedom joint module to achieve the functions of the five-axis robot include the following: The 2R1T parallel mechanism in a five-axis robot is divided into three types according to its function: two attitude adjustments + one position adjustment, one attitude adjustment + two position adjustments, and three position adjustments. Based on the different functions of the 2R1T parallel mechanism, the serial single-degree-of-freedom joint module in a five-axis robot is divided into two position adjustments, one attitude adjustment + one position adjustment, and two attitude adjustments.

5. The method for integrating a 2R1T parallel mechanism into a five-axis robot configuration according to claim 4, characterized in that: In step three, different types of configurations are selected and combined. The topological configurations of the five-axis robot are divided into the following three combinations: Case 1: The two rotating axes of the 2R1T parallel mechanism are both close to the moving platform. The functions of the 2R1T parallel mechanism are 1. Position adjustment and 2. Attitude adjustment. It requires two single-degree-of-freedom joint modules for position adjustment to be connected in series. This configuration is defined as the double position adjustment type, corresponding to the PU type in the 2R1T parallel mechanism configuration. Case 2: The two rotation axes of the 2R1T parallel mechanism are both close to the stationary platform. The function of the 2R1T parallel mechanism is 3-position adjustment. It requires two single-degree-of-freedom joint modules for attitude adjustment to be connected in series. This configuration is defined as the double attitude adjustment type, which corresponds to the UP type in the configuration of the 2R1T parallel mechanism. Scenario 3: In a 2R1T parallel mechanism, one rotation axis is close to the moving platform, and the other rotation axis is close to the stationary platform. The 2R1T parallel mechanism is a 2-position adjustment and 1-attitude adjustment mechanism. It requires one single-degree-of-freedom joint module for position adjustment and one single-degree-of-freedom joint module for attitude adjustment to be connected in series. This configuration is defined as a one-attitude adjustment and one-position adjustment type, corresponding to the RPR type in the 2R1T parallel mechanism configuration. Different combinations are selected according to the situation to achieve the corresponding required functions.

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