Parallel rope drive balancing control system

Abstract

The application discloses a parallel rope driving balance control system, which comprises a control module, a first driving and transmission module, a second driving and transmission module, a rope and a force analysis module. The balance control method comprises the following steps: S1, solving the pose matrix of the parallel rope driving platform; S2, calculating the natural coordinates of the connecting points of the rope and the controlled object; S3, calculating the rope disengagement drum cut point coordinate value and obtaining the expression of the pulley position; S4, obtaining the expression of the 2n rope and pulley cut point; S5, obtaining n sets of force balance equations; S6, obtaining n sets of torque balance equations; S7, constructing an optimization solving model; S8, solving the n rope tension and the n pulley position coordinate value; S9, solving the rope length; and S10, solving the motor rotation angle. The application solves the problem that the parallel rope driving platform cannot guarantee balance under any pose condition, and can realize higher-precision and stronger-robustness motion control.

Description

Technical Field

[0001] This invention relates to a parallel rope-driven balance control system, belonging to the field of robotics technology. Background Technology

[0002] Rope-driven parallel robots possess the characteristics of simple structure, low manufacturing cost, large workspace, good flexibility, low inertia, high load-to-weight ratio, high speed and acceleration, high energy efficiency, and high dynamics. However, many core issues still exist for this system, requiring breakthrough innovative technologies to solve or improve it.

[0003] ZL201810810331.X (A Parallel Rope-Driven Marine Salvage System) proposes a four-rope control system that calculates the end effector's pose using a measurement unit. This invention adjusts the system stiffness by changing the rope tension, but does not describe the specific changes or the corresponding equations. The rope node positions in this system are fixed, making it impossible to achieve stability of the rope-driven platform by adjusting the magnitude and position of the force. ZL201810427634.3 (A Redundancy-Removing Control Method for an Eight-Rope Parallel Gravity Compensation System) uses six active ropes and two follower ropes to actively control the position and attitude of a six-DOF platform, proposing a fundamental kinematic model. ZL201610512458.4 (A Rope-Driven Parallel Robot Motion Control Method Considering Elastic Influence and Compensation) considers and compensates for the rope's elasticity, optimizing rope tension and designing the controller through a dynamic model. Existing inventions control the position and tension of eight ropes through eight sets of drive systems to adjust the posture of a six-degree-of-freedom motion object at its end. However, existing examples cannot guarantee that the platform's posture will always be in the desired state due to force imbalance. Furthermore, the pulley connection points in existing inventions are fixed, making it impossible to adjust the pulley positions. In summary, parallel rope-driven platform systems still have room for improvement in terms of flexibility and adjustability.

[0004] Rigid parallel drive platforms control platform movement through rigid push rods, which can provide both tension and thrust, eliminating force imbalance issues. In contrast, rope-driven parallel platforms use ropes that can only provide tension, not thrust, leading to force imbalances in many positions and orientations. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and provide a parallel rope-driven balance control system. By adjusting the pulley position, it achieves reconfigurability and the goal of completing multiple tasks. This method proposes a solution to force imbalance by analyzing the relationship between the platform's pose, the magnitude, position, and direction of the driving rope tension. Through the force balance control method, the parallel rope-driven system can maintain a state of force balance under various poses. This method analyzes how to adjust the magnitude, position, and direction of the rope tension, thereby improving the platform's robustness, adjustability, and other performance characteristics.

[0006] The technical solution of this invention is:

[0007] This invention discloses a parallel rope-driven balance control system, comprising: a control module, a first drive and transmission module, a second drive and transmission module, and a rope and force analysis module; wherein,

[0008] The control module, based on the motor rotation angle sent by the force analysis module and the real-time pose information output by the controlled object, outputs first motor control information to the first drive and transmission module and second motor control information to the second drive and transmission module.

[0009] The first drive and transmission module includes a drum, which controls the drum to rotate according to the first motor control information output by the control module, thereby adjusting the length of the rope wound on the drum.

[0010] The second drive and transmission module includes pulleys and a fixed frame. It adjusts the position of each pulley on the fixed frame according to the second motor control information output by the control module, thereby adjusting the position of the key nodes of each rope.

[0011] The force analysis module, based on the pose information output by the controlled object, obtains the motor's rotation angle through a force balance control method and sends it to the control module.

[0012] Furthermore, in the above-mentioned parallel rope drive system, the force balance control method specifically includes:

[0013] Calculate the connection point B between the rope and the controlled object. i The coordinates of the point;

[0014] Calculate the point of tangency A where the rope detaches from the drum based on the drum's placement. i The coordinates of the point;

[0015] Calculate the pulley position O based on the relative positions of the pulley and the fixed frame. i The expression for a point;

[0016] According to A i Point B i The coordinates of the point and O iThe expression for the points yields 2n ​​points of tangency between the rope and the pulley, O. i1 Point and O i2 The expression for a point;

[0017] According to the B i Point coordinates and O i2 The point expression yields n sets of force balance equations and n rope tensions F. i The expression;

[0018] According to the B i Point coordinates and the tension F of n ropes i From the expression, we obtain n sets of torque balance equations;

[0019] Based on the force balance equation and torque balance equation, an optimal solution model is constructed.

[0020] Based on the aforementioned optimization solution model, solve for the n rope tensions F. i and n pulley positions O i The coordinates of the point;

[0021] According to A i Point B i dot, O i1 Point and O i2 Use the coordinates of the point to calculate the rope length l. i ;

[0022] Based on the n rope lengths l i Solve for the rotation angle N of the motor controlling the drum. i .

[0023] Furthermore, in the above-mentioned parallel rope drive system, the calculation of the connection point B between the rope and the controlled object... i The coordinates of the point are as follows:

[0024]

[0025] T 1-6 (p x ,p y ,p z ,φ x ,φ y ,φ z )=T1(p x )·T2(p y )·T3(p z )·T4(φ x )·T5(φ y )·T6(φ z )

[0026]

[0027]

[0028] Where x, y, and z are the values ​​of a point projected onto the three coordinate axes; (x Bi ,y Bi ,z Bi Point B is the connection point between the rope and the platform. i The coordinates of a point in the natural coordinate system; (x Bi_P ,y Bi_P ,z Bi_P ) is B i The coordinates of the point relative to the coordinate system of the parallel rope-driven platform body; p x ,p y ,p z For the three position data of the parallel rope-driven platform, φ represents the distance translated along the three coordinate axes; x ,φ y ,φ z The three attitude data for the parallel rope-driven platform are the angles of rotation along the three coordinate axes; T i T1 is the i-th transformation matrix, and T1 to T6 are the pose matrices of the parallel rope-driven platform.

[0029] Furthermore, in the above parallel rope drive system, the pulley position O is calculated. i The expression for a point is as follows:

[0030] or

[0031] Where H1, H2, and H3 are constants related to the dimensions of the fixing frame; △ i is the motor rotation angle that controls the i-th pulley; k is the proportionality factor between the motor rotation angle and the pulley translation distance.

[0032] Furthermore, in the above-mentioned parallel rope drive system, according to A i Point B i The coordinates of the point and O i The expression for the points yields 2n ​​points of tangency between the rope and the pulley, O. i1 Point and O i2 The expression for a point is as follows:

[0033]

[0034] Where r is the pulley radius; (x Ai ,y Ai ,z Ai ) is A i The coordinates of the point; (x Bi ,y Bi ,z Bi ) is B iThe coordinates of the point; (x Oi ,y Oi ,z Oi ) is O i The coordinates of the point; (x oi1 ,y oi1 ,z oi1 ) is O i1 The coordinates of the point, (x oi2 ,y oi2 ,z oi2 ) is O i2 The coordinates of the point, where r is the pulley radius.

[0035] Furthermore, in the above-mentioned parallel rope drive system, according to the B... i Point coordinates and O i2 The point expression yields n sets of force balance equations and n rope tensions F. i The expression is as follows:

[0036]

[0037]

[0038] Among them, F i,x F i,y F i,z These are the tension F of the i-th rope. i Components of force along the x, y, and z axes; |F i | is the tension F of the i-th rope. i Size; These are the tension F of the i-th rope. i The directions of the component forces along the x-axis, y-axis, and z-axis satisfy the following relationship: G is the magnitude of the platform's gravity; (x oi2 ,y oi2 ,z oi2 ) is O i2 The coordinates of the point; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point.

[0039] Furthermore, in the above-mentioned parallel rope drive system, according to the B... i Point coordinates and the tension F of n ropes i From the expression, we obtain n sets of moment balance equations, specifically:

[0040]

[0041] Where n is the number of driving ropes; τ i,x τ i,yτ i,z These are the torques τ generated by the i-th rope on the parallel rope-driven platform. i Components of torque in the x-axis, y-axis, and z-axis directions; |F i | is the tension F of the i-th rope. i Size; These are the tension F of the i-th rope. i The direction of the component forces along the x-axis, y-axis, and z-axis.

[0042] Furthermore, in the aforementioned parallel rope drive system, an optimization solution model is constructed based on the force balance equation and torque balance equation, specifically as follows:

[0043]

[0044] Where n is the number of driving ropes; F i,x F i,y F i,z These are the tension F of the i-th rope. i Components of force along the x, y, and z axes; |F i | is the tension F of the i-th rope. i Size; These are the tension F of the i-th rope. i The directions of the force components along the x, y, and z axes; G is the magnitude of the platform's gravity; τ i,x τ i,y τ i,z These are the torques τ generated by the i-th rope on the parallel rope-driven platform. i Component moments in the x-axis, y-axis, and z-axis directions; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point; △ i is the motor rotation angle that controls the i-th pulley; k is the proportionality factor between the motor rotation angle and the pulley translation distance.

[0045] Furthermore, in the above-mentioned parallel rope drive system, according to A i Point B i dot, O i1 Point and O i2 Use the coordinates of the point to calculate the rope length l. i Specifically:

[0046]

[0047] Where r is the radius of the pulley; (x oi1 ,y oi1 ,z oi1 ) is O i1The coordinates of the point; (x oi2 ,y oi2 ,z oi2 ) is O i2 The coordinates of the point; (x Ai ,y Ai ,z Ai ) is A i The coordinates of the point; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point.

[0048] Furthermore, in the above-mentioned parallel rope drive system, based on the lengths l of the n ropes... i Solve for the rotation angle N of the motor controlling the drum. i Specifically:

[0049]

[0050] Where D is the diameter of the roller.

[0051] The advantages of this invention over the prior art are as follows:

[0052] (1) The present invention proposes a novel parallel rope drive system including a control module, a first drive and transmission module, a second drive and transmission module, a rope and force analysis module, to achieve the technical effect of adjustable rope length and pulley position.

[0053] (2) By using the cosine theorem, right triangle theorem, etc., this invention analyzes the relationship between the geometric parameters and key node coordinates in the parallel rope-driven platform, constructs a kinematic parameter mapping framework, and realizes the technical effect that any configuration of the parallel rope-driven platform can meet the geometric constraints.

[0054] (3) This invention is designed for adjustable parallel rope-driven platforms. It constructs a three-dimensional force model and a three-dimensional torque model to solve the problem of force imbalance under any position.

[0055] (4) This invention uses all rope tensions |F i The objective function is to minimize the sum of the forces. The constraints are the force balance equations in the three directions, the moment balance equations in the three directions, and the tension of all ropes being greater than or equal to zero. An optimization solution model is constructed, which can solve for 2n variables in the parallel rope-driven platform and achieve the technical effect of solving for the control parameters. Attached Figure Description

[0056] Figure 1 This is a flowchart of the parallel rope-driven balance control method of the present invention;

[0057] Figure 2 This is a framework diagram of a parallel rope-driven balance control system according to the present invention;

[0058] Figure 3 This is a schematic diagram of a parallel rope-driven balance control system according to the present invention;

[0059] Figure 4 This is a schematic diagram of the spatial geometric relationship of the key points of the present invention;

[0060] Figure 5 This is a conventional rope layout diagram of the present invention, wherein (a) is a front view of the rope drive platform, (b) is a diagram of the pull-down rope distribution, and (c) is a diagram of the pull-up rope distribution;

[0061] Figure 6 This is a reconfigurable rope layout diagram of the present invention, wherein (a) is a front view of the rope drive platform, (b) is a diagram of the pull-down rope distribution, and (c) is a diagram of the pull-up rope distribution;

[0062] Figure 7 This is a diagram showing the adjustable parallel rope-driven platform and pulley positions of the present invention, wherein (a) is a front view, (b) is a left view, (c) is a top view, and (d) is an oblique view.

[0063] Figure 8 This is a diagram showing the changes in position and attitude parameters of the parallel rope-driven platform of the present invention, where (a) represents the attitude parameter φ. x The variation diagram (b) shows the attitude parameter φ. y The variation diagram (c) shows the attitude parameter φ. z The variation diagram (d) shows the position parameter p. x The variation diagram (e) shows the position parameter p. y The variation diagram (f) shows the position parameter p. z Change diagram;

[0064] Figure 9 This is a diagram of the motion process of the parallel rope-driven platform of the present invention, wherein (a) is an oblique view, (b) is an XY view, (c) is an XZ view, and (d) is a YZ view;

[0065] Figure 10 These are the pulley position change curves of the present invention, wherein (a) is the change curve of the first pulley position, (b) is the change curve of the second pulley position, (c) is the change curve of the third pulley position, (d) is the change curve of the fourth pulley position, (e) is the change curve of the fifth pulley position, (f) is the change curve of the sixth pulley position, (g) is the change curve of the seventh pulley position, and (h) is the change curve of the eighth pulley position.

[0066] Figure 11These are the rope tension variation curves of the present invention, wherein (a) is the tension variation curve of the first rope, (b) is the tension variation curve of the second rope, (c) is the tension variation curve of the third rope, (d) is the tension variation curve of the fourth rope, (e) is the tension variation curve of the fifth rope, (f) is the tension variation curve of the sixth rope, (g) is the tension variation curve of the seventh rope, and (h) is the tension variation curve of the eighth rope. Detailed Implementation

[0067] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0068] like Figure 2 and Figure 3 As shown, the present invention provides a parallel rope-driven balance control system, comprising:

[0069] The parallel rope drive system includes the following modules: control module, first drive and transmission module, second drive and transmission module, rope and force analysis module.

[0070] The control module, based on the real-time pose information output by the controlled object and the key node position data output by the force analysis module, converts the lengths of the eight ropes into the rotation angles of the eight motors via conversion unit 1, outputting the first motor control information to the first drive and transmission module; and converts the positions of the eight key nodes into the rotation angles of the eight motors via conversion unit 2, outputting the second motor control information to the second drive and transmission module. The inputs to this module are the task to be completed, the real-time pose information of the parallel rope drive platform, and the key node position data output by the force analysis module. The output of this module is the motor control information, with the position data of the i-th motor denoted as N. i .

[0071] The first drive and transmission module includes a drum. One end of a rope is fixedly connected to the drum, and a portion of the rope is wound around the drum. Based on the first motor control information output by the control module, the module controls the motor's movement, thereby controlling the drum's rotation and adjusting the length of the rope wound around the drum. The main function of this module is to adjust the length of each rope exposed outside the drum. The length of the i-th rope not wound around the drum surface is denoted as l. i Hereinafter, this will be referred to simply as the length of the i-th rope.

[0072] The second drive and transmission module includes pulleys and a fixed frame, with the center point of the pulleys referred to as O. i The control module controls the movement of the motors based on the second motor control information output by the control module, thereby adjusting the position of each pulley on the fixed frame and thus adjusting the position of the key nodes of each rope. In this module, the pulley tangent point O is analyzed. i1 Point and O i2The location of the point lays the groundwork for analyzing the direction of the rope tension.

[0073] The force analysis module, based on the pose information output by the controlled object, obtains the planned rope length l through a force balance control method. i With respect to the center point O of the moving pulley i The position of the i-th rope is sent to the control module. The rope controls the pose of the parallel rope-driven platform through tension; the contact point between the i-th rope and the parallel rope-driven platform is B. i Point, direction of tension is The magnitude of the tension is |F i |

[0074] like Figure 1 As shown, the specific steps of the force balance control method are as follows:

[0075] Step S1: Based on the pose information (x) of the parallel rope driven platform p ,y p ,z p ,φ x ,φ y ,φ z Solve for the six transformation matrices T1-T6, and multiply the six transformation matrices together to obtain the pose matrix T of the parallel rope-driven platform. 1-6 ;

[0076] Step S2: Calculate the connection point B between the rope and the controlled object. i The natural coordinates of a point (x) Bi ,y Bi ,z Bi );

[0077] Step S3: Calculate the rope detachment point A from the drum. i The coordinates of the point give the pulley position O. i The expression for a point;

[0078] Step S4 according to A i Point B i The coordinates of the point and O i The expression for the points yields 2n ​​points of tangency between the rope and the pulley (O i1 Point and O i2 The expression for a point;

[0079] Step S5 according to the B i Point coordinates and O i2 The point expression yields n sets of force balance equations and n rope tensions F. i The expression;

[0080] Step S6 according to the B i Point coordinates and the tension F of n ropes iFrom the expression, we obtain n sets of torque balance equations;

[0081] Step S7: Based on the force balance equation and the moment balance equation, construct an optimal solution model;

[0082] Step S8: Based on the optimization solution model, solve for the n rope tensions F. i and n pulley positions O i The coordinates of the point;

[0083] Step S9 according to A i Point B i dot, O i1 Point and O i2 Use the coordinates of the point to calculate the rope length l. i ;

[0084] Step S10: Based on the n rope lengths l i Solve for the rotation angle N of the motor controlling the drum. i .

[0085] In this invention, the value of i ranges from 1 to 8, K is an integer, and n is the number of driving ropes, taking n=8 as an example.

[0086] Specifically as follows:

[0087] Step S1: Based on the pose information (x) of the parallel rope driven platform p ,y p ,z p ,φ x ,φ y ,φ z Solve for the six transformation matrices T1-T6, and multiply the six transformation matrices together to obtain the pose matrix T of the parallel rope-driven platform. 1-6 .

[0088] The parallel rope drive module includes the parallel rope drive platform and its key information. This includes three position data points of the parallel rope drive platform (p... x ,p y ,p z ) and three attitude data (φ x ,φ y ,φ z The origin of the coordinate system of the parallel rope driven platform is set as the centroid of the parallel rope driven platform, denoted as point P.

[0089] Next, we construct the geometric model of the parallel rope-driven platform. x ,p y ,p z The three position data for the parallel rope-driven platform are the distances translated along the three coordinate axes, φ. x ,φ y,φ z The three attitude data points for the parallel rope-driven platform are the rotation angles along the three coordinate axes. The pose information of the platform can be represented by six transformation matrices, and B can be solved using these matrices. i The location data of the points. The six transformation matrices T1-T6 are shown below:

[0090]

[0091]

[0092] T i This is the i-th transformation matrix. Multiplying these six transformation matrices together yields the pose matrix of the parallel rope-driven platform, denoted as T. 1-6 The calculation formula is as follows:

[0093] T 1-6 (p x ,p y ,p z ,φ x ,φ y ,φ z )=T1(p x )·T2(p y )·T3(p z )·T4(φ x )·T5(φ y )·T6(φ z )

[0094] S2 calculates the connection point B between the rope and the controlled object. i The natural coordinates of a point (x) Bi ,y Bi ,z Bi ).

[0095] Rope connection point B i The coordinates of a point in the natural coordinate system are denoted as (x... Bi ,y Bi ,z Bi ), where B is an unknown quantity; i The coordinates of a point relative to the coordinate system of the parallel rope-driven platform are denoted as (x... Bi_P ,y Bi_P ,z Bi_P ), where is a known quantity related to the parallel rope-driven platform structure. The above coordinates satisfy the following transformation rules:

[0096]

[0097] From the above formula, we can see the coordinates (x) Bi ,y Bi ,z Bi ) and six pose information (px ,p y ,p z ,φ x ,φ y ,φ z (Related to)

[0098] S3 calculates the rope detachment point from the drum at point A. i The coordinates of the point give the pulley position O. i The expression for a point.

[0099] Rope detachment from roller tangent point A i The coordinates of the point (x) Ai ,y Ai ,z Ai The value is related to the placement of the roller and is a known constant.

[0100] Because of gravity, the pulley cannot move along the direction of gravity, i.e., the z-axis. Therefore, the pulley position O is... i The coordinates of the point (x) Oi ,y Oi ,z Oi z in ) Oi This is a fixed value. The pulley is mounted on a fixed frame in the x-axis or y-axis direction, allowing for translational movement along either the x-axis or y-axis. The x-axis can be changed via the control information from the second motor output by the control module. Oi or y Oi The value.

[0101] or

[0102] Where H1, H2, and H3 are constants related to the dimensions of the fixing frame; △ i is the motor rotation angle that controls the i-th pulley; k is the proportionality factor between the motor rotation angle and the pulley translation distance.

[0103] S4 according to A i Point B i The coordinates of the point and O i The expression for the points yields 2n ​​points of tangency between the rope and the pulley (O i1 Point and O i2 An expression for a point.

[0104] The spatial geometric relationship diagram of the key points in this embodiment is shown below. Figure 4 As shown, in a parallel rope drive system, one end of the rope is fixedly connected to the drum. After winding around the drum for a certain distance, the rope stops winding around the drum surface. The point at which the rope detaches from the drum is called A. i Point B; the other end of the rope is fixedly connected to the parallel rope drive platform via a hook, and the connection point is called B. iPoint; the position of the pulley is O. i Point; the rope passes through the pulley in the middle, and the rope intersects the pulley at two points of tangency, called O. i1 dot, O i2 point.

[0105] Because O i1 dot, O i2 Since point O is the point of tangency, the angle at that point is a right angle, meaning the line O is perpendicular to the line O. i O i1 Perpendicular to line A i O i1 Straight line O i O i2 Perpendicular to line B i O i2 .

[0106] A spatial right triangle exists under the following geometric condition: the sum of the squares of the lengths of the two shorter sides is equal to the square of the length of the hypotenuse. Therefore, we can conclude that:

[0107]

[0108] in, It is O i1 Point and A i The distance between points, and other symbols with a line as a superscript all represent the distance between two points, where r is the pulley radius.

[0109] Because of the straight line O i O i1 Perpendicular to line A i O i1 Straight line O i O i2 Perpendicular to line B i O i2 Since the product of the vectors corresponding to the lines is zero, we can obtain:

[0110]

[0111] in, It is O i Point and O i1 The direction vector of the line connecting the points; other symbols with arrows as superscripts all represent the direction vector between the two points.

[0112] Because point O i It is the center of the circle, point O. i1 and point O i2 Since the point is on the arc, we can obtain:

[0113]

[0114] Substituting the coordinate values ​​into the three formulas above, we can summarize as follows:

[0115]

[0116] Among them, (x Ai ,y Ai ,z Ai ) is A i The coordinates of the point; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point are known quantities; (x Oi ,y Oi ,z Oi ) is O i The coordinates of a point include k△ i The expression; (x oi1 ,y oi1 ,z oi1 ) is O i1 The coordinates of the point; (x oi2 ,y oi2 ,z oi2 ) is O i2 The coordinates of the point are unknowns.

[0117] S5 according to the B i Point coordinates and O i2 By using point expressions, we obtain n sets of force balance equations.

[0118] The conditions for balancing a parallel rope-driven platform include force balance in three orthogonal directions and torque balance in three orthogonal directions.

[0119] The platform is in equilibrium under the condition of rope tension F. i The net force along the z-axis is equal to gravity G, and the net force along the x and y axes is zero. The tension F in the i-th rope... i The components of the force along the x-axis, y-axis, and z-axis are F, respectively. i,x F i,y F i,z The formulas for calculating the forces in these three orthogonal directions are as follows:

[0120]

[0121] Where n is the number of driving ropes; G is the magnitude of the platform's gravity; |F i |The tension F in the i-th rope i Size; The tension F of the i-th rope is respectively i The direction of the component forces along the x-axis, y-axis, and z-axis.

[0122] These three parameters must satisfy the following conditions:

[0123]

[0124] Rope tension direction The solution formula is as follows:

[0125]

[0126] Among them, (x oi2 ,y oi2 ,z oi2 ) is O i2 The three-dimensional coordinates of the point; (x Bi ,y Bi ,z Bi ) is B i The three-dimensional coordinates of the point.

[0127] S6 according to the B i Point coordinates and the tension F of n ropes i From the expression, we obtain n sets of torque balance equations.

[0128] The platform's torque equilibrium condition is the rope tension F. i The torque τ generated on the parallel rope-driven platform i It equals zero, as shown below:

[0129]

[0130] In other words, the rope tension F i The resultant torque along the x-axis, y-axis, and z-axis is equal to zero, that is:

[0131]

[0132] The tension F in the i-th rope i The torque τ generated on the parallel rope-driven platform i The component moments in the x, y, and z axes are respectively τ i,x τ i,y τ i,z The calculation formula is as follows:

[0133]

[0134] Substituting the magnitude of the force and the distance of the force from the axis, we can obtain:

[0135]

[0136] Where n is the number of driving ropes, |F i | is the tension F of the i-th rope. i Size; These are the tension F of the i-th rope.i The direction of the component forces along the x-axis, y-axis, and z-axis.

[0137] Ropes can only provide tension, not thrust; therefore, the tension F in each rope is... i All must meet the following conditions:

[0138] F i ≥0 (4)

[0139] S7 constructs an optimal solution model based on the force balance equation and the moment balance equation.

[0140] When the platform is in equilibrium, it needs to simultaneously satisfy the three force balance equations shown in formula (1), the three torque balance equations shown in formula (3), and the constraint conditions shown in formula (4).

[0141] To solve for 2n variables, an optimization model needs to be constructed. The objective function in the optimization model is constructed according to the task and can be set as, but is not limited to, the following examples: minimizing the sum of rope tensions, minimizing the maximum rope tension, and ensuring the pulley position is close to the initial position. Taking the minimization of the sum of rope tensions as an example, the resulting optimization model is shown below:

[0142]

[0143] Where n is the number of driving ropes; F i,x F i,y F i,z These are the tension F of the i-th rope. i Components of force along the x, y, and z axes; |F i | is the tension F of the i-th rope. i Size; These are the tension F of the i-th rope. i The directions of the force components along the x, y, and z axes; G is the magnitude of the platform's gravity; τ i,x τ i,y τ i,z These are the torques τ generated by the i-th rope on the parallel rope-driven platform. i Component moments in the x-axis, y-axis, and z-axis directions; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point; △ i is the motor rotation angle that controls the i-th pulley; k is the proportionality factor between the motor rotation angle and the pulley translation distance.

[0144] The objective function of the optimization model is the tension in all ropes |F iThe sum of these forces must be minimized. The constraints of the optimization model include force balance equations in three directions, moment balance equations in three directions, all rope tensions being greater than or equal to zero, and pulley O... i The translation position of the point k△ i Within the defined range [k△] min ,k△ max ]Inside.

[0145] S8 uses the confidence region algorithm to solve for the n rope tensions F based on the aforementioned optimization solution model. i and n pulley positions O i The coordinates of the point.

[0146] S9 according to A i Point B i dot, O i1 Point and O i2 Use the coordinates of the point to calculate the rope length l. i .

[0147] By changing the rope length l i With pulley O i The position of a point can change the tension in the rope, thereby changing the orientation of the platform. A i Point B i dot, O i dot, O i1 Point and O i2 The spatial geometric relationship of points is as follows Figure 4 As shown, the length l of the i-th rope i It can be calculated using the following formula:

[0148]

[0149] in, It is O i1 Point and A i The distance between two points; other symbols with a superscript line also represent the distance between two points; O i1 O i O i2 It is O i1 Click to O i2 Distance between points and arcs, with the center of the arc at point O. i Point; r is the radius of the pulley.

[0150] and The calculation formula is as follows:

[0151]

[0152] Arc distance O i1 O i O i2The calculation formula is as follows:

[0153] O i1 O i O i2 =r·∠(O i1 O i O i2 )

[0154] ∠(O i1 O i O i2 ) is O i1 O i line segment and O i2 O i The angle between line segments can be obtained using the Law of Cosines:

[0155]

[0156] Based on the above derivation, the rope length l i The calculation formula can be summarized as follows:

[0157]

[0158] Where r is the radius of the pulley; (x oi1 ,y oi1 ,z oi1 ) is O i1 The coordinates of the point; (x oi2 ,y oi2 ,z oi2 ) is O i2 The coordinates of the point; (x Ai ,y Ai ,z Ai ) is A i The coordinates of the point; (x Bi ,y Bi ,z Bi ) is B i The coordinates of the point.

[0159] S10 based on the n rope lengths l i Solve for the rotation angle N of the motor controlling the drum. i .

[0160] Motor rotation angle N i With rope length l i The mapping relationship between them is as follows:

[0161] l i =πDN i

[0162] In the formula, D is the diameter of the drum; N i This represents the position data of the i-th motor, i.e., the motor rotation angle.

[0163] If the rope length l is known i The rotation angle N of the motor controlling the drum can then be calculated using the following formula. i :

[0164]

[0165] In summary, the above steps analyze the positions of key nodes based on spatial set relationships and construct the relationships between various parameters. An optimization solution model is built upon the mapping model, force balance equations, and moment balance equations. The final solved variables satisfy the platform's pose and force balance requirements.

[0166] This invention not only increases the feasible range of motion of the platform but also ensures platform stability. Simulation verification shows that the method of this invention is superior to the corresponding traditional method, as detailed below:

[0167] Example 1: Example 1 is an instance corresponding to the traditional method.

[0168] The schematic diagram of the rope layout of the parallel rope drive platform shown in Example 1 is as follows: Figure 5 As shown, a spherical shape is used to represent the parallel rope drive platform. The solid circles in the figure are the connection points between the ropes and the platform. Eight connection points are evenly distributed on the upper part of the platform. Four connection points are selected to provide downward tension through four ropes (marked as the lower ropes in the figure). Eight connection points are evenly distributed on the lower part of the platform. Four connection points are selected to provide upward tension through four ropes (marked as the upper ropes in the figure).

[0169] Simulation revealed that in traditional parallel rope-driven platform systems, only the rope tension F can be adjusted. i The size and direction of The system is fixed, meaning there are n variables. Regardless of the connection point selection, the parallel rope-driven platform cannot guarantee force balance in its initial pose (the initial position is the middle position, as shown in the figure), meaning it cannot simultaneously satisfy formulas (1), (3), and (4). The platform also struggles to meet force balance conditions at other positions and poses, which will not be discussed in detail here. Traditional solutions only analyze the pose required to achieve force balance at a given position, without actively controlling and adjusting the platform's pose, and thus cannot simultaneously satisfy the six balance conditions for the platform in the desired position and pose.

[0170] Example 2: Example 2 is an instance corresponding to the method in this invention.

[0171] A schematic diagram of the rope layout of the parallel rope-driven platform is shown below. Figure 6As shown in the figure, the solid circle in the figure is the connection point between the rope and the platform, and this connection point is fixed. Five connection points are evenly distributed on the upper part of the platform, and four connection points are selected. The four ropes marked as the upper rope in the figure provide an upward tension. Five connection points are evenly distributed on the lower part of the platform, and four connection points are selected. The four ropes marked as the lower rope in the figure provide a downward tension.

[0172] In a parallel rope-driven platform, there is a sliding degree of freedom between the pulley and the fixed frame. The corresponding initial state diagram is shown below. Figure 7 As shown, the simplified sphere in the figure is a platform. By constructing a basic kinematic and static model, it can be determined that this instance is in equilibrium at its initial position.

[0173] During the period from 0s to 100s, the parallel rope-driven platform moves from one position to another, and its attitude also changes from one attitude to another. The diagram illustrating the changes in position and attitude parameters is shown below. Figure 8 As shown, the corresponding formula is as follows:

[0174]

[0175] The motion process of a parallel rope-driven platform can be obtained through this invention, such as... Figure 9 As shown. The curves showing the changes in pulley positions related to the positions of the eight ropes are as follows. Figure 10 As shown. The tension variation curves of the eight ropes are as follows. Figure 11 As shown.

[0176] As illustrated by the examples, by changing the rope length and pulley position, the parallel rope-driven platform can be guaranteed to move to the desired position and posture. Compared to the traditional solution in Example 1, the method proposed in this invention in Example 2 more easily achieves large-scale rotational motion and torque balance.

[0177] As can be seen from the examples provided, the novel parallel rope drive system proposed in this invention can not only adjust the rope tension F i The size and direction of It can also be adjusted because the direction satisfies formula (3), so there are 3n adjustable variables in the system. This invention changes the pulley O i Position the point, adjust the direction of the rope tension, and move the pulley O. i The point's position is restricted to a fixed frame and can only be translated in one direction (it can be set to move along the x-axis or y-axis, thus changing only the x-axis). oi or y oi Therefore, there are 2n adjustable variables in the system. Increasing the number of adjustable variables from n to 2n ensures that the platform can reach the desired pose within its range of motion, maintains a balanced state, and contains some redundant variables.

[0178] This invention proposes a parallel rope-driven balance control system, which expands the platform's motion space and improves its control accuracy and stability. A general kinematic analysis model is also presented, capable of analyzing rope-driven parallel platforms with different configurations. This enables more precise and robust motion control, promoting the development of related technologies for rope-driven parallel robots / astronaut microgravity training platforms.

[0179] This invention can be applied to astronaut microgravity training platforms, parallel drive systems, rope drive platforms, and reconfigurable platforms.

[0180] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0181] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A parallel rope-driven balance control system, characterized in that, include: The module comprises a control module, a first drive and transmission module, a second drive and transmission module, and a rope and force analysis module; among which, The control module, based on the motor rotation angle sent by the force analysis module and the real-time pose information output by the controlled object, outputs first motor control information to the first drive and transmission module and second motor control information to the second drive and transmission module. The first drive and transmission module includes a drum, which controls the drum to rotate according to the first motor control information output by the control module, thereby adjusting the length of the rope wound on the drum. The second drive and transmission module includes pulleys and a fixed frame. It adjusts the position of each pulley on the fixed frame according to the second motor control information output by the control module, thereby adjusting the position of the key nodes of each rope. The force analysis module, based on the pose information output by the controlled object, obtains the motor's rotation angle through a force balance control method and sends it to the control module. The force balance control method is specifically as follows: Calculate the connection point between the rope and the controlled object. B i The coordinates of the point; Calculate the point at which the rope detaches from the drum based on the drum's placement. A i The coordinates of the point; Calculate the pulley position based on the relative positions of the pulley and the fixed frame. O i The expression for a point; According to the above A i point, B i The coordinates of the point and O i The expression for the point yields 2. n The point of tangency between the rope and the pulley O i1 Dot and O i2 The expression for a point; According to the above B i Point coordinates and O i2 dot expression, get n Force equilibrium equations and n rope tension F i The expression; According to the above B i Point coordinates and n rope tension F i The expression yields n A set of moment balance equations; Based on the force balance equation and torque balance equation, an optimal solution model is constructed. Based on the aforementioned optimization solution model, solve... n rope tension F i and n Each pulley position O i The coordinates of the point; According to the above A i point, B i point, O i1 Dot and O i2 Use the coordinates of the point to calculate the rope length. l i ; According to the above n rope length l i Solve for the rotation angle of the motor controlling the drum. N i .

2. The parallel rope-driven balance control system according to claim 1, characterized in that: The connection point between the calculation rope and the controlled object B i The coordinates of the point are as follows: ， ， ， ， ， in, x , y , z This represents the numerical value of a point projected onto the three coordinate axes; x Bi , y Bi , z Bi () is the connection point between the rope and the platform. B i The coordinates of a point in the natural coordinate system; x Bi_P , y Bi_P , z Bi_P )for B i The coordinates of the point relative to the coordinate system of the parallel rope-driven platform body; The three position data for the parallel rope-driven platform are the distances translated along the three coordinate axes; The three attitude data for the parallel rope-driven platform are the angles of rotation along the three coordinate axes; T i It is the first i Transformation matrices, T 1~ T 6 is the pose matrix of the parallel rope-driven platform.

3. The parallel rope-driven balance control system according to claim 1, characterized in that: Calculate the position of the pulley O i The expression for a point is as follows: or in, H 1. H 2. H 3 is a constant related to the size of the mounting bracket; △ i It is to control the first i The motor rotation angle of each pulley; k It is the proportionality factor between the motor rotation angle and the pulley translation distance.

4. The parallel rope-driven balance control system according to claim 1, characterized in that: According to the above A i point, B i The coordinates of the point and O i The expression for the point yields 2. n The point of tangency between the rope and the pulley O i1 Dot and O i2 The expression for a point is as follows: in,( x Ai , y Ai , z Ai )for A i The coordinates of the point; x Bi , y Bi , z Bi )for B i The coordinates of the point; x Oi , y Oi , z Oi )for O i The coordinates of the point; x oi1 , y oi1 , z oi1 )yes O i1 The coordinates of the point; x oi2 , y oi2 , z oi2 )yes O i2 The coordinates of the point; r Let be the radius of the pulley.

5. A parallel rope-driven balance control system according to claim 1, characterized in that: According to the above B i Point coordinates and O i2 dot expression, get n Force equilibrium equations and n rope tension F i The expression is as follows: in, F i,x , F i,y , F i,z They are the first i rope tension F i Along x axis, y axis, z Component of force along the axial direction; | F i |Is the i rope tension F i Size; , , They are the first i rope tension F i Along x axis, y axis, z The direction of the component force along the axial direction satisfies the following relationship: ; G It is the magnitude of the platform's gravity; x oi2 , y oi2 , z oi2 )yes O i2 The coordinates of the point; x Bi , y Bi , z Bi )yes B i The coordinates of the point.

6. A parallel rope-driven balance control system according to claim 1, characterized in that: According to the above B i Point coordinates and n rope tension F i The expression yields n The set of moment balance equations are as follows: in, n Number of drive ropes; τ i,x , τ i,y , τ i,z They are the first i The torque generated by the rope on the parallel rope-driven platform τ i exist x Axial direction, y Axial direction, z Component of torque in the axial direction; | F i |Is the i rope tension F i Size; , , They are the first i rope tension F i Along x axis, y axis, z The direction of the component force along the axis.

7. A parallel rope-driven balance control system according to claim 1, characterized in that: Based on the force balance equations and moment balance equations, an optimization solution model is constructed as follows: in, n Number of drive ropes; F i,x , F i,y , F i,z They are the first i rope tension F i Along x axis, y axis, z Component of force along the axial direction; | F i |Is the i rope tension F i Size; , , They are the first i rope tension F i Along x axis, y axis, z The direction of the component force along the axis; G It refers to the magnitude of the platform's gravity; τ i,x , τ i,y , τ i,z They are the first i The torque generated by the rope on the parallel rope-driven platform τ i exist x Axial direction, y Axial direction, z The component of the moment in the axial direction; x Bi , y Bi , z Bi )yes B i The coordinates of the point; △ i It is to control the first i The motor rotation angle of each pulley; k It is the proportionality factor between the motor rotation angle and the pulley translation distance.

8. A parallel rope-driven balance control system according to claim 1, characterized in that: According to the above A i point, B i point, O i1 Dot and O i2 Use the coordinates of the point to calculate the rope length. l i Specifically: in, r The radius of the pulley; x oi1 , y oi1 , z oi1 )yes O i1 The coordinates of the point; x oi2 , y oi2 , z oi2 )yes O i2 The coordinates of the point; x Ai , y Ai , z Ai )yes A i The coordinates of the point; x Bi , y Bi , z Bi )yes B i The coordinates of the point.

9. A parallel rope-driven balance control system according to claim 2, characterized in that: According to the above n rope length l i Solve for the rotation angle of the motor controlling the drum. N i Specifically: in, D It is the diameter of the roller.

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