A 6-DOF attitude adjustment solution method based on series-parallel structure

Abstract

The present invention provides a 6-DOF posture adjustment solution method based on a serial-parallel structure, and relates to the technical field of posture adjustment solution methods. The 6-DOF posture adjustment solution method based on a serial-parallel structure includes S1. joint data initialization, S2. restriction adjustment introduction, S3. joint data acquisition and preprocessing, S4. mechanism kinematics solution, S5. current posture superposition control amount, S6. target posture solution, S7. mechanism inverse kinematics solution, S8. mechanism target position decomposition, S9. mechanism target position verification and restriction, S10. solution completion. By decoupling the calculation of the upper and lower parts of the parallel mechanism, that is, first completing their respective calculations separately and then coupling, this method improves the solution efficiency, simplifies the solution process, enhances the expansion capability of the system, and effectively reduces the influence of cumulative errors by dispersing and averaging errors.

Description

Technical Field

[0001] The present invention relates to the technical field of attitude adjustment solution methods, and in particular to a 6-DOF attitude adjustment solution method based on a series-parallel structure. Background Art

[0002] As the core power unit of aircraft, aircraft engines are mainly divided into two categories: turbine and piston. Turbine engines are widely used in aircraft. Their working principle is to generate thrust by burning fuel; while piston engines are mostly used in small aircraft and generate power through the reciprocating motion of the piston. The design of aircraft engines is a complex interdisciplinary process, and its key performance indicators cover thrust, efficiency, weight and reliability. Given its large size and weight, it must be installed with the help of a lifting structure to ensure safety and precise docking. The lifting device is not only convenient for fine-tuning and support, but also becomes a key tool in the installation and removal process, especially in space-constrained environments. During the installation of aircraft engines, the degree of freedom attitude adjustment solution method of the lifting mechanism is crucial, which involves fine-tuning the engine to ensure that it can be installed accurately and correctly.

[0003] During the installation of aircraft engines, a major technical problem faced when using a lifting mechanism for engine installation is that the mechanism needs to have high strength and rigidity. In order to meet these requirements, it is usually necessary to provide a larger initial geometric size, which will lead to a series of design and manufacturing challenges. First, the larger size will increase the weight of the mechanism, thereby affecting the overall transportation and handling efficiency. Secondly, the larger size and weight require stronger materials, which not only increases the cost, but may also affect the dynamic response performance of the mechanism. In addition, the larger initial geometric size may also lead to space limitation problems during the installation process. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the shortcomings of the prior art, the present invention provides a 6-DOF attitude adjustment solution method based on a series-parallel structure, which solves the problem in the prior art that the strength and stiffness of the mechanism are high and a higher initial geometric size of the mechanism needs to be provided.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented by the following technical solutions: a 6-DOF posture adjustment solution method based on a series-parallel structure, specifically comprising the following steps:

[0008] S1. Joint data initialization

[0009] First, initialize the data of all joints, including the initial position, velocity and acceleration of each joint. For the 6-DOF posture adjustment mechanism, record the initial state of each rotational joint and linear joint.

[0010] S2. Limit regulation import

[0011] Import motion restrictions for all joints, including angle restrictions and travel restrictions;

[0012] S3. Joint data collection and preprocessing

[0013] During the movement, the current state data of the joint is collected in real time, including reading data from sensors, applying low-pass filters to remove high-frequency noise, and normalizing the data;

[0014] S4. Mechanism kinematics solution

[0015] According to the initial state and the collected data, the position and posture changes of the mechanism during the movement are calculated; the coordinates of each point in the initial state

[0016] X 1，0 =(0,0,0)=(l x ,0,0)=(l x , l y ,0),X 4，0 =(0, l y ,0)

[0017] The first rotation: Rotate θ around the x-axis, the coordinates of each point after rotation

[0018] X1=(0,0,0), X2=(l x ,0,0)=(l x , l y cosθ,l y sinθ),

[0019] X4=(0,l y cosθ,l y sinθ)

[0020] Second rotation: Rotate φ around the y-axis, the coordinates of each point after rotation

[0021] X'1=(0,0,0), X'2=(x2,y2,z2)=(x3,y3,z3)=(0,l y cosθ,l y sinθ)

[0022] Find X_4, constraints:

[0023]

[0024] Find X_3, constraints:

[0025]

[0026] That is: X'3 = X'2 + X'4

[0027] Solution

[0028] x2=l x cosφ;y2=l x sinθsinφ;z2=-l x cosθsinφ

[0029] Then find the change in the length of each rod, assuming that the rise and fall of 1 is z1

[0030] d1=z1

[0031] d4=l y sinθ+z1

[0032] Assume that the initial length of the rod is d0

[0033]

[0034] Kinematics:

[0035]

[0036] Next, find the transformation matrix of the coordinate system defined at the ball joint of the support leg of bracket 1. The transformation order is: translation along z, rotation around x, rotation around y.

[0037]

[0038]

[0039]

[0040] Next, calculate the bracket adjustment motion, which includes a rotation and a translation

[0041] Set the coordinate system at the pin hole No. 5 and set the distance between the two pins l_p

[0042] d5=x5=l p sinψ+x5

[0043]

[0044] Next, find the transformation matrix of the coordinate system defined at 5

[0045]

[0046] Next, the upper bracket is translated along the y-axis and then rotated around the x-axis.

[0047]

[0048]

[0049]

[0050] Next, integrate the various rotation matrices and express them as the forward and backward transformation of the engine coordinate system, where e is the origin state and e' is the state after the movement.

[0051] Kinematics:

[0052] T e′→e =T 1→e T 1′→1 T5→1T 5′→5 T 7→5 T 7′→7 T e→7

[0053] S5. Current posture superposition control amount

[0054] Superimpose the control amount on the current posture to predict the future posture of the mechanism under the control command;

[0055] S6. Target pose calculation

[0056] According to the task requirements, the target posture that the mechanism needs to achieve is calculated. The target setting includes setting the target position and posture, and calculating the posture change from the current posture to the target posture;

[0057] S7. Inverse kinematics solution of the mechanism

[0058] According to the target posture, calculate the angle and position that each joint needs to achieve, including the rotation part and the translation part;

[0059] S8. Organizational target position decomposition

[0060] Decompose the target pose into the target position and pose of each joint;

[0061] S9. Mechanism target position verification and limitation

[0062] Check the calculated target positions to ensure they do not violate any motion constraints;

[0063] S10. Solving completed

[0064] After all solution steps are completed, the motion plan of the mechanism is confirmed and ready for execution.

[0065] Preferably, the rotation part in the inverse kinematics solution of the S7. mechanism:

[0066]

[0067] Translation part:

[0068]

[0069] (III) Beneficial effects

[0070] The present invention provides a 6-DOF posture adjustment solution method based on a serial-parallel structure. It has the following beneficial effects: the solution method realizes independent processing of each part by decoupling the parallel mechanism of the upper and lower parts. This parallel processing method significantly improves the calculation efficiency. The calculation process after decoupling is more concise and direct, effectively reducing the calculation complexity, thereby accelerating the overall solution speed. The standard kinematics and geometric transformation methods are adopted to standardize the solution process and facilitate programming. The method has good adaptability and can be applied to different mechanism structures and motion requirements. It can be easily adapted to various application scenarios by simply adjusting the corresponding motion restrictions and parameters. The decoupling characteristics make it easy to add new joints or change the mechanism structure without redesigning the entire solution process. By distributing the calculation of the posture changes of each part, the influence of a single calculation error on the entire system is reduced. The averaging of errors can be achieved by fusing and processing multiple sensor data, thereby improving the robustness of the system. In the serial-parallel structure, errors may be amplified in multiple links. By decoupling calculation, errors can be corrected separately in each link, effectively reducing error accumulation. By collecting and processing joint status data in real time, errors can be corrected in time to avoid errors from being amplified in the system. This method can adapt to different motion restrictions, such as angle restrictions and stroke restrictions, so that the mechanism can move in a wider range. It can meet different control instructions and task requirements, showing excellent adaptability. This method can be directly applied to actual mechanical systems, such as robots, automation equipment, etc., and has high practicality. At the same time, due to the simplicity and standardization of the solution method, system maintenance and upgrades have also become more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 It is a schematic diagram of the serial-parallel 6-DOF posture adjustment mechanism of the present invention;

[0072] Figure 2 is the first three-dimensional coordinate of the present invention;

[0073] Figure 3 It is the second three-dimensional coordinate of the present invention. DETAILED DESCRIPTION

[0074] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, 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.

[0075] Example:

[0076] like Figure 1-3 As shown, the embodiment of the present invention provides a 6-DOF posture adjustment solution method based on a series-parallel structure, which specifically includes the following steps:

[0077] S1. Joint data initialization

[0078] First, initialize the data of all joints, including the initial position, velocity and acceleration of each joint. For the 6-DOF posture adjustment mechanism, record the initial state of each rotary joint and linear joint. Before starting any movement, you first need to determine the initial state of each joint, including the angle, position and velocity of each rotary joint and linear joint, because subsequent calculations are based on the initial values, so initialization ensures that the system starts moving from a known and possible state;

[0079] S2. Limit regulation import

[0080] Import motion restrictions for all joints, including angle restrictions and travel restrictions. This step is the key to safe operation and can ensure that the mechanism operates within a safe range.

[0081] S3. Joint data collection and preprocessing

[0082] During the movement, the current state data of the joint is collected in real time, including reading data from sensors, applying low-pass filters to remove high-frequency noise, and normalizing the data, which facilitates subsequent calculations and processing;

[0083] S4. Mechanism kinematics solution

[0084] According to the initial state and the collected data, the position and posture changes of the mechanism during the movement are calculated; the coordinates of each point in the initial state

[0085] X 1，0 =(0,0,0)=(l x ,0,0)=(l x , l y ,0),X 4，0 =(0, l y ,0)

[0086] The first rotation: Rotate θ around the x-axis, the coordinates of each point after rotation

[0087] X1=(0,0,0), X2=(l x ,0,0)=(l x , l y cosθ,l y sinθ),

[0088] X4=(0,l y cosθ,l y sinθ)

[0089] Second rotation: Rotate φ around the y-axis, the coordinates of each point after rotation

[0090] X'1=(0,0,0), X'2=(x2,y2,z2)=(x3,y3,z3)=(0,l y cosθ,l y sinθ)

[0091] Find X_4, constraints:

[0092]

[0093] Find X_3, constraints:

[0094]

[0095] That is: X'3 = X'2 + X'4

[0096] Solution

[0097] x2=l x cosφ;y2=l x sinθsinφ;z2=-l x cosθsinφ

[0098] Then find the change in the length of each rod, assuming that the rise and fall of 1 is z1

[0099] d1=z1

[0100] d4=l y sinθ+z1

[0101] Assume that the initial length of the rod is d0

[0102]

[0103] Kinematics:

[0104]

[0105] Next, find the transformation matrix of the coordinate system defined at the ball joint of the support leg of bracket 1. The transformation order is: translation along z, rotation around x, rotation around y.

[0106]

[0107]

[0108]

[0109] Next, calculate the bracket adjustment motion, which includes a rotation and a translation

[0110] Set the coordinate system at the pin hole No. 5 and set the distance between the two pins l_p

[0111] d5=x5=l p sinψ+x5

[0112]

[0113] Next, find the transformation matrix of the coordinate system defined at 5

[0114]

[0115] Next, the upper bracket is translated along the y-axis and then rotated around the x-axis.

[0116]

[0117]

[0118]

[0119] Next, integrate the various rotation matrices and express them as the forward and backward transformation of the engine coordinate system, where e is the origin state and e' is the state after the movement.

[0120] Kinematics:

[0121] T e ' →e =T 1→e T1' →1 T 5→1 T5' →5 T 7→5 T7' →7 T e→7

[0122] Inverse Kinematics:

[0123] Rotating part:

[0124]

[0125] Translation part:

[0126]

[0127] Specifically, the position and posture changes of the mechanism during the movement are calculated. This process includes:

[0128] Coordinates of each point in the initial state: record the coordinates of all key points at the beginning of the mechanism.

[0129] First rotation: Rotate θ around the x-axis and update the coordinates of each point.

[0130] Second rotation: Rotate φ around the y-axis and update the coordinates of each point again.

[0131] Solve X_4 and X_3: Solve the coordinates of specific points based on the constraints.

[0132] Kinematic calculation: calculate the change in the length of each rod and the overall position change of the mechanism

[0133] S5. Current posture superposition control amount

[0134] The control amount is superimposed on the current posture to predict the future posture of the mechanism under the control command. This step is necessary because it takes into account the impact of the control command on the movement of the mechanism. The specific calculation process includes:

[0135] Convert control amount into pose change

[0136] Update the current pose;

[0137] S6. Target pose calculation

[0138] According to the task requirements, the target posture that the mechanism needs to achieve is calculated. The target setting includes setting the target position and posture, and calculating the posture change from the current posture to the target posture;

[0139] S7. Inverse kinematics solution of the mechanism

[0140] According to the target posture, calculate the angle and position that each joint needs to achieve, including the rotation part and the translation part;

[0141] S8. Organizational target position decomposition

[0142] The target pose is decomposed into the target position and pose of each joint. The decomposition process includes:

[0143] For each joint, assign a target position based on its kinematic relationship

[0144] Consider interactions and constraints between joints;

[0145] S9. Mechanism target position verification and limitation

[0146] The calculated target positions are checked to ensure that they do not violate any motion constraints. The checking steps include:

[0147] Check if the target position of each joint is within the allowed range

[0148] Adjust the target position to meet the constraints;

[0149] S10. Solving completed

[0150] After all solution steps are completed, the motion plan of the mechanism is confirmed and ready for execution.

[0151] Specifically, in the above specific embodiments, Figure 1 As shown, the structural form of the present invention is: the lower layer is a parallel structure composed of 4 lifting mechanisms, the upper layer is a set of linear motion mechanisms, and the upper layer and the lower layer are connected in series through two sets of transverse mechanisms in the middle. Finally, compared with the existing solution algorithm, the solution method decouples the upper and lower parallel mechanisms and couples them after completing the calculations separately. It has high solution efficiency, simple solution method, strong expansion capability, dispersed and averaged errors, and reduces the impact of cumulative errors.

[0152] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A 6-DOF posture adjustment solution method based on a series-parallel structure, characterized in that: The specific steps include: S1. Joint data initialization First, initialize the data of all joints, including the initial position, velocity and acceleration of each joint. For the 6-DOF posture adjustment mechanism, record the initial state of each rotational joint and linear joint. S2. Limit regulation import Import motion restrictions for all joints, including angle restrictions and travel restrictions; S3. Joint data collection and preprocessing During the movement, the current state data of the joint is collected in real time, including reading data from sensors, applying low-pass filters to remove high-frequency noise, and normalizing the data; S4. Mechanism kinematics solution According to the initial state and the collected data, the position and posture changes of the mechanism during the movement are calculated; Coordinates of each point in the initial state X 1,0 =(0,0,0),X 2,0 =(l x ,0,0),X 3,0 =(l x ,l y ,0),X 4,0 =(0,l y ,0) The first rotation: Rotate θ around the x-axis, the coordinates of each point after rotation X1=(0,0,0),X2=(l x ,0,0)=(l x ,L y cosθ,l y sinθ), X4=(0,l y cosθ,l y sinθ) Second rotation: Rotate φ around the y-axis, the coordinates of each point after rotation X’1=(0,0,0),X’2=(x2,y2,z2)=(x3,y3,z3)=(0,l y cosθ,l y sinθ) Find X_4, constraints: Find X_3, constraints: That is: X'3=X'2+X'4 Solution x2=l x cosφ;y2=l x sinθsinφ;z2=-l x cosθsinφ Then find the change in the length of each rod, assuming that the rise and fall of 1 is z1 d1=z1 d4=l y sinθ+z1 Assume that the initial length of the rod is d0 Kinematics: Next, find the transformation matrix of the coordinate system defined at the ball joint of the support leg of bracket 1. The transformation order is: translation along z, rotation around x, rotation around y. Next, calculate the bracket adjustment motion, which includes a rotation and a translation Set the coordinate system at the pin hole No. 5 and set the distance between the two pins l_p <h2 style=";text-align:left;direction:ltr">d5 = x5 = l<h2 style=";text-align:left;direction:ltr"> p <h2 style=";text-align:left;direction:ltr"> sinψ+x5 Next, find the transformation matrix of the coordinate system defined at 5 Next, the upper bracket is translated along the y-axis and then rotated around the x-axis. Next, integrate the various rotation matrices and express them as the forward and backward transformation of the engine coordinate system, where e is the origin state and e' is the state after the movement. Kinematics: T e ' →e =T 1→e T1' →1 T 5→1 T5' →5 T 7→5 T7' →7 T e→7 S5. Current posture superposition control amount Superimpose the control amount on the current posture to predict the future posture of the mechanism under the control command; S6. Target pose calculation According to the task requirements, the target posture that the mechanism needs to achieve is calculated. The target setting includes setting the target position and posture, and calculating the posture change from the current posture to the target posture; S7. Inverse kinematics solution of the mechanism According to the target posture, calculate the angle and position that each joint needs to achieve, including the rotation part and the translation part; S8. Organizational target position decomposition Decompose the target pose into the target position and pose of each joint; S9. Mechanism target position verification and limitation Check the calculated target positions to ensure they do not violate any motion constraints; S10. Solving completed After all solution steps are completed, the motion plan of the mechanism is confirmed and ready for execution.

2. A 6-DOF posture adjustment method based on a series-parallel structure according to claim 1, characterized in that: The rotation part in the inverse kinematics solution of the S7 mechanism: Translation part:

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