Lifting rope cable-stayed prevention control system and control method based on acceleration feedback

Abstract

According to the lifting rope cable-stayed prevention control system and method based on acceleration feedback provided by the invention, the component of the dip angle of the lifting rope in each direction is indirectly controlled by adjusting the acceleration of the lifting rope in each direction, so that the dip angle of the lifting rope can be adjusted in real time in the working process of a crane; various problems caused by overlarge dip angle or large swing amplitude change of the lifting rope are solved, and potential safety hazards are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of crane control, and in particular relates to a suspension rope anti-slanting control system and a control method based on acceleration feedback. Background Art

[0002] Lifting equipment such as gantries and cranes are widely used in various industries, and are often seen in industrialized manufacturing workshops, warehouses, docks, construction sites, and other places where heavy or large goods need to be transported over short distances. The moving route of a crane to transport goods has a vertical moving distance and a horizontal moving distance, which are often combined into an inclined trajectory. Therefore, the lifting rope is not always in a vertical state during the transportation process, but is in an inclined state, especially during turning, acceleration, and deceleration. The lifting rope is prone to swing and is difficult to control. This will lead to a decrease in the efficiency of the crane, and at the same time bring greater safety hazards to surrounding personnel, facilities, and the crane itself.

[0003] Suppressing excessive inclination of the hoisting rope and preventing the crane from swaying is a complex problem that scholars at home and abroad are still studying. In the current research process, the rope force of the hoisting rope is often calculated based on the simple pendulum model. However, on the one hand, the rope length of the simple pendulum model is fixed, which is distorted by the actual working conditions where the rope length changes all the time. On the other hand, the inertia of the rope and the hoisted object affects the accuracy of the calculation. Summary of the invention

[0004] Based on the above technical status, the present invention provides a rope anti-slanting control system and control method based on acceleration feedback, hoping to indirectly control the components of the rope inclination in each direction by adjusting the acceleration of the rope in each direction, so that the inclination of the rope can be adjusted in real time during the operation of the crane, thereby solving various problems caused by excessive inclination of the rope or large changes in swing amplitude, and avoiding safety hazards.

[0005] The technical solution adopted by the present invention is as follows: a method for controlling the anti-slanting of a suspension rope based on acceleration feedback, comprising the following steps:

[0006] S1: Construct the coordinate system O with a point on the top of the rope that does not shake as the origin O, and the center of gravity of the object being hoisted as the origin O m Point constructs a moving coordinate system O with coordinate axes parallel to the inertial system m ;

[0007] S2: Obtain the rope tension F of the suspension rope, the length l of the suspension rope, and the angle θ between the suspension rope and the two mutually perpendicular vertical planes zoy and zox in the coordinate system O x ,θ y ;

[0008] S3: Constructing a sliding film controller based on equivalent sliding film control theory:

[0009] S3.1: The sliding film controller in the x-axis direction is:

[0010]

[0011] Where: u ox is the dynamic compensation amount:

[0012]

[0013] Where: F is the rope tension of the lifting rope; l is the length of the lifting rope; m is the mass of the object being lifted; d x is the projection length of the suspension rope l on the plane zoy; d x_real-time It represents the target length of the projection of the suspension rope on the plane zoy; represents the first-order derivative of dx with respect to time; and Respectively represent d x_real-time First and second derivatives with respect to time; c 1x and c 2x All are coefficients;

[0014] u x is a symbolic controller with an exponential convergence term:

[0015] u x =γ x sgn(s)+λ x s, where γ x ,λ x are all unknown coefficients, s is the sliding surface equation, and sgn is the symbolic function;

[0016] S3.2: The principle of the sliding film controller in the x-axis direction is the same as that of the sliding film controller in the y-axis direction:

[0017]

[0018] S4: The processor calculates the thrust that the drive motor needs to provide based on the synovial controller and the data obtained in step S2; the thrust of the drive motor is calculated as follows:

[0019]

[0020] Where: is the thrust of the x-axis drive motor, is the thrust of the y-axis drive motor; M y is the total weight of the lifting components and the objects being lifted, M l is the weight of the x-axis moving trolley; F x 、F y They are coordinate systems O m The components of the rope tension F in the x and y directions;

[0021] Based on the above formula, the thrust required in the x-axis direction and the y-axis direction is:

[0022]

[0023] S5: The controller receives the instruction from the processor and controls the x-axis drive motor and the y-axis drive motor to perform corresponding actions.

[0024] In the above step S3, when constructing the sliding film controller in the x-axis direction, the following steps are also included:

[0025] S3.1.1: Decompose the rope tension F of the sling into:

[0026]

[0027] Where: Fx, Fy and Fz are the components of the rope tension F in the x, y and z axes in the coordinate system Om, respectively; θx and θy are the angles between the rope and its projections in the plane zoy and the plane zox, respectively;

[0028] S3.1.2: Based on step S3.1, the kinetic equation is obtained:

[0029]

[0030] in: It is the component of the total mass center acceleration in each axis direction of the inertial system, and m is the mass of the suspended object;

[0031] S3.1.3: For the coordinate origin O and the coordinate origin O m The geometric relationship between them can be expressed mathematically:

[0032]

[0033] Where: x om and om O m Coordinates on the horizontal plane, x o and o are the coordinates of the origin O, and l is the length of the rope;

[0034] Take the second-order derivative of time on both sides of the above equation:

[0035]

[0036] Where: d x is the projection length of the suspension rope l on the plane zoy, d y is the projection length of the suspension rope l on the plane zox;

[0037] S3.1.4: Based on the above equations, the state space equation of the crane rope system is obtained:

[0038]

[0039] S3.1.5: Based on the swing angle relationship expressed in steps S3.1 and S3.2, the target acceleration of the suspended object in the horizontal x-axis direction Expressed as:

[0040]

[0041] Where: is the target acceleration of the suspended object in the x-axis direction; θ x_real-time is the target angle between the suspension rope and its projection on the zoy plane; d x_real-time is the target length of the projection of the lifting rope on the plane zoy, l is the length of the lifting rope, and m is the weight of the object being lifted;

[0042] S3.1.6: Construct the deflection equation for the suspension rope system:

[0043] e x =d x -d x_real-time

[0044] dx is the length of the projection of the rope on the plane zoy, d x_real-time is the target length of the projection of the rope on the plane zoy, when e x When it is 0, the actual length of the rope projected on the plane is the same as the desired control target length, and the design sliding membrane surface equation is:

[0045]

[0046] Combined with the state space equation in step S3.4, the following equation is obtained by taking the derivative on both sides of the synovial surface s:

[0047]

[0048] make Get the dynamic compensation u ox , the dynamic compensation u ox and symbol controller u x The synovial film controller in the x-axis direction is obtained by combination; the principle of constructing the synovial film controller in the y-axis direction is the same as that of constructing the synovial film controller in the x-axis direction.

[0049] In the above step S2, a three-wheel tension sensor is used to measure the rope tension of the suspension rope; an encoder is used to measure the length of the suspension rope; and a two-dimensional laser displacement sensor is used to measure the angle between the suspension rope and its projection on the plane zoy and the plane zox.

[0050] Furthermore, the present invention also seeks to protect a suspension rope anti-slanting control system based on acceleration feedback, which uses the above control method to control the movement trajectory of the suspension rope; comprising:

[0051] A lifting assembly, wherein the lifting assembly is mounted on a y-axis moving trolley, and the y-axis driving motor drives the y-axis moving trolley to move, thereby driving the lifting assembly to move;

[0052] An x-axis moving trolley is driven by an x-axis driving motor to move along the crane frame in the x-axis direction;

[0053] The y-axis moving trolley is installed on the x-axis moving trolley and is driven by the y-axis driving motor to move along the y-axis direction on the x-axis moving trolley;

[0054] The lifting assembly includes: a base, a reel, a lifting rope, a three-wheel tension sensor, a two-dimensional laser displacement sensor and an encoder. The base is fixed on a y-axis moving trolley or the base serves as a y-axis moving trolley. The reel is rotatably hingedly supported on the base, the lifting rope is wound on the reel, and the free end of the lifting rope passes through the three-wheel tension sensor, the encoder and the two-dimensional laser displacement sensor in sequence and then hangs down to connect with the hook.

[0055] A processor, which calculates the thrust of the x-axis drive motor and the y-axis drive motor in real time based on the synovial controller;

[0056] The controller receives the instruction from the processor to drive the x-axis driving motor and the y-axis driving motor to move.

[0057] The three-wheel tension sensor is installed at one end of the base to measure the tension of the suspension rope; the free end of the suspension rope is hung downward after passing through the three-wheel tension sensor, and the encoder is installed on the side of the three-wheel tension sensor to measure the length of the hanging rope; the two-dimensional laser displacement sensor is installed below the three-wheel tension sensor to measure the deflection displacement data of the suspension rope.

[0058] In the technical solution disclosed in the present invention, the designed controller can calculate the motor thrust in the x-axis direction and the y-axis direction respectively during the movement of the suspension rope, so that the suspension assembly can reach the desired target acceleration and change the two angles θ of the suspension rope in real time. x and θ y ,θ x and θ y The change actually allows the inclination angle of the suspension rope to be adjusted, thereby controlling the suspension rope to move within a safe and expected inclination angle, ensuring the safety of the suspension rope's movement trajectory and avoiding excessive deflection. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1It is a schematic diagram of the overall structure of the principle framework of the control system of the present invention;

[0060] Figure 2 It is a partial enlarged view of the lifting assembly of the control system of the present invention;

[0061] Figure 3 It is an auxiliary diagram for introducing the principle of the control method of the present invention;

[0062] In the figure: 1. base, 2. lifting motor, 3. reducer, 4. reel, 5. three-wheel tension sensor, 6. encoder, 7. two-dimensional laser displacement sensor, 8. lifting rope, 9. y-axis drive motor, 10. x-axis drive motor. DETAILED DESCRIPTION

[0063] Figure 1 It is a schematic diagram of the overall structure of the principle framework of the control system of the present invention. The x-axis and y-axis movement ranges are set up to simulate the movement trajectory of the crane's lifting assembly in three-dimensional space. An x-axis moving trolley is built on the gantry, and the x-axis driving motor 10 drives the x-axis moving trolley to move. The x-axis moving trolley is set in a double-track form. A y-axis moving trolley is built on the x-axis moving trolley, and the y-axis driving motor 9 drives the y-axis moving trolley to move along the double track of the x-axis moving trolley. The lifting assembly is installed on the y-axis moving trolley. The y-axis moving trolley serves as a support for the movement of the lifting assembly. A separate structure can be designed, or the base of the lifting assembly can be directly used as the y-axis moving trolley, that is, in the subsequent analysis, the weight of the y-axis moving trolley is added to the lifting assembly. The lifting assembly moves in the y-axis direction with the movement of the y-axis moving trolley, and moves in the x-axis direction with the movement of the x-axis moving trolley.

[0064] See also Figure 2 , is a partial enlarged view of the lifting component of the control system of the present invention, including a base 1, which is fixedly mounted on the y-axis moving trolley, and a reel 4 is installed on the base 1 through a hinge support, and a lifting motor 2 is connected to the reel 4 through a reducer 3 to drive the reel 4 to rotate; a lifting rope 8 is rolled up on the reel 4, one end of the lifting rope 8 is fixedly locked with the reel 4, and the other end is connected to the hook as the lifting and retracting end. During the lifting operation, the lifting motor 2 drives the reel 4 to rotate forward and reverse to retract and release the lifting rope 8, and lift and lower the goods in the vertical direction, and the movement of the y-axis moving trolley and the x-axis moving trolley drives the lifting component to move in position in azimuth, thereby completing the movement of the lifted goods in space. In order to achieve the purpose of the anti-slanting control of the lifting rope of the present invention, the control system of the present invention installs a three-wheel tension sensor 5 and a two-dimensional laser displacement sensor 7, as well as an encoder 6 on the lifting component, which are used to respectively obtain the rope tension of the lifting rope 8 in the working state, the displacement data of the rope offset, and the length l of the rope in real time.

[0065] like Figure 2A three-wheel tension sensor 5 is installed at the end of the base 1, a two-dimensional laser displacement sensor 7 is installed below the three-wheel tension sensor 5, and an encoder 6 is installed on the three-wheel tension sensor 5. The suspension rope 8 is led out from the reel 4 and then passes through the three-wheel tension sensor 5, and then naturally leads downward after passing through the two-dimensional laser displacement sensor 7. The use of tension sensors and displacement sensors to obtain tension, displacement and other data has mature applications in many systems and will not be elaborated on.

[0066] The following is combined with Figure 3 The principle of the control method of the present invention is described in detail.

[0067] See also Figure 3 , a coordinate system is constructed based on the lifting rope 8 of the lifting assembly, wherein the coordinate system O is a coordinate system with the upper end of the rope (where the rope exits the pulley at the lower end of the three-wheel tension sensor) as the origin; m It is a coordinate system with the center of gravity of the hoisted object as the origin, and a moving coordinate system with coordinate axes parallel to the inertial system, that is, a coordinate system in which the x-axis and y-axis are parallel to the movement of the hoisting assembly along the x-axis and y-axis directions respectively. The hoisting rope 8 is in an inclined state due to the tilted movement in the working state, that is, the two coordinate origins O m The line between and O represents the obliquely pulled rope, and the traction force F of the rope is measured by the three-wheel tension sensor 5; the length of the rope extending downward from point O, i.e., the rope length l, is measured by the encoder 6; the displacement offset of the rope in the x-axis and y-axis directions when the rope is in the oblique state is measured by the two-dimensional laser displacement sensor 7, and the installation position of the two-dimensional laser displacement sensor 7 determines its vertical distance from point O. In the figure, GH and GK are the displacement data measured by the two-dimensional laser displacement sensor 7, and the small plane where G, H, and K are located represents the installation position of the two-dimensional laser displacement sensor 7. Obviously, the angle between the rope and the plane zoy and the plane zox can be known through the geometric relationship.

[0068] Tension data, rope length, and rope offset angle can all be measured. The principle of the controller of the present invention is described in detail below, where the rope tension F can be described by the following equation:

[0069]

[0070] Where: Fx, Fy and Fz are coordinate systems O m The components of the rope tension F in the x, y, and z directions, θ x ,θ y are the angles between the rope and its projections in the plane zoy and the plane zox respectively.

[0071] By transforming the above formula (1) and ignoring the damping in the system, the dynamic equation is obtained:

[0072]

[0073] in: It is the component of the total center of mass acceleration in each axis direction of the inertial system, and m is the mass of the suspended object.

[0074] Combination Figure 3 , O point and O m The geometric relationship between the point positions is as follows:

[0075]

[0076] Where: x om and om O m Coordinates on the horizontal plane, x o and o are the coordinates of the origin O, and l is the length of the rope.

[0077] Taking the second-order derivative of both sides of equation (3) with respect to time, we get the following equation:

[0078]

[0079] Where: d x is the projection length of the suspension rope l on the plane zoy, d y is the projection length of the suspension rope l on the plane zox.

[0080] Combining equations (1) to (4), we obtain the following state space equation.

[0081]

[0082] From formula (4), we can see that by controlling d x and d y The control θ can be realized x and θ y , that is, the offset of the suspension rope can be controlled. Since the structure of the dynamic equation of the suspension rope on the x-axis and y-axis is the same, the design of the controller can also be the same. The following takes the control of the suspension rope in the x-axis direction as an example to illustrate the design principle of the entire control system.

[0083] The target acceleration of the suspended object in the horizontal x-axis direction (i.e. the acceleration expected to be achieved, which is the control target) is: Combining the corresponding swing angles in equations (1) and (2), we can obtain equations (6) and (7):

[0084]

[0085] Where: is the target acceleration of the suspended object in the x-axis direction; θ x_real-time is the target angle between the suspension rope and its projection on the zoy plane; dx_real-time is the target length of the projection of the lifting rope on the plane zoy, l is the length of the lifting rope, and m is the weight of the object being lifted.

[0086] The deviation equation for this system is as follows:

[0087] e x =d x -d x_real-time (8)

[0088] Where: d x is the length of the projection of the rope on plane zoy, d x_real-time is the target length of the projection of the suspension rope on the plane zoy. x When it is 0, the actual length of the rope projected on the plane is the same as the desired control target length, and the movement trajectory of the rope is constrained within a predetermined and safe range.

[0089] The controller of the present invention is designed based on the equivalent synovial film control theory, wherein:

[0090] The sliding film surface equation is:

[0091]

[0092] Combining the above equations (5) to (9), the following equation can be obtained, which is recorded as equation (10).

[0093]

[0094] make We can obtain the following equation:

[0095]

[0096] where u ox Express the dynamic compensation amount, using a symbolic controller with an exponential convergence term:

[0097] u x =γ x sgn(s)+λ x s (12)

[0098] Where γ x ,λ x are all unknown coefficients, s is the above sliding surface equation, and sgn is the sign function.

[0099] Combining equation (11) and equation (12) to obtain the sliding mode controller based on equivalent control is as follows:

[0100]

[0101] The stability of the above controller is proved as follows: Let the Lyapunov function be: V = s 2 / 2, and taking the derivative of this equation, we get the following equation:

[0102] (14)

[0103] When γ x >0,λ x When >0, the system is stable.

[0104] The above is the controller design for the reverse direction of the x-axis. The same is true for the y-axis direction, which can be expressed as:

[0105]

[0106] The sliding film controllers for the x-axis and y-axis constructed based on the present invention can calculate the motor thrust required to control the suspension rope to achieve the target acceleration on the x-axis and y-axis respectively:

[0107]

[0108] Where: is the thrust of the x-axis driving motor 10, is the thrust of the y-axis drive motor 9. Based on the above formula (15), the processor can calculate the thrusts that the x-axis drive motor 10 and the y-axis drive motor 9 need to provide, and then the controller drives the two motors to move.

[0109]

[0110] Where: M y is the total weight of the lifting components and the objects being lifted (if the y-axis moving trolley is set separately, it includes the weight of the y-axis moving trolley), M l is the weight of the x-axis moving cart.

Claims

1. A method for preventing the rope from oblique pulling based on acceleration feedback, characterized in that: S1: Construct the coordinate system O with a point on the top of the rope that does not shake as the origin O, and the center of gravity of the object being hoisted as the origin O m Point constructs a moving coordinate system O with coordinate axes parallel to the inertial system m ; S2: Obtain the rope tension F of the suspension rope, the length l of the suspension rope, and obtain the angles θx and θy between the suspension rope and two mutually perpendicular vertical planes zoy and zox in the coordinate system O; S3: Constructing a sliding film controller based on equivalent sliding film control theory: S3.1: The sliding film controller in the x-axis direction is: Where: u ox is the dynamic compensation amount: Where: F is the rope tension of the lifting rope; l is the length of the lifting rope; m is the mass of the object being lifted; d x is the projection length of the suspension rope l on the plane zoy; d x_real-time It represents the target length of the projection of the suspension rope on the plane zoy; represents the first-order derivative of dx with respect to time; and Respectively represent d x_real-time First and second derivatives with respect to time; c 1x and c 2x All are coefficients; u x is a symbolic controller with an exponential convergence term: u x =γ x sgn(s)+λ x s, where γ x ,λ x are all unknown coefficients, s is the sliding surface equation, and sgn is the symbolic function; S3.2: The principle of the sliding film controller in the x-axis direction is the same as that of the sliding film controller in the y-axis direction: S4: The processor calculates the thrust that the drive motor needs to provide based on the synovial controller and the data obtained in step S2; S5: The controller receives the instruction from the processor and controls the x-axis drive motor and the y-axis drive motor to perform corresponding actions.

2. The control method according to claim 1, further characterized in that: The thrust of the driving motor is calculated in step S4 as follows: Where: is the thrust of the x-axis drive motor, is the thrust of the y-axis drive motor; M y is the total weight of the lifting components and the objects being lifted, M l is the weight of the x-axis moving trolley; Fx and Fy are the components of the rope tension F in the x-axis and y-axis directions in the coordinate system Om, respectively; Based on the above formula, the thrust required in the x-axis direction and the y-axis direction is:

3. The control method according to claim 1 or 2, further characterized in that: When constructing the sliding membrane controller in the x-axis direction, the following steps are also included: S3.1.1: Decompose the rope tension F of the sling into: Where: Fx, Fy and Fz are the components of the rope tension F in the x, y and z axes in the coordinate system Om, respectively; θx and θy are the angles between the rope and its projections in the plane zoy and the plane zox, respectively; S3.1.2: Based on step S3.1, the kinetic equation is obtained: in: It is the component of the total mass center acceleration in each axis direction of the inertial system, and m is the mass of the suspended object; S3.1.3: For the coordinate origin O and the coordinate origin O m The geometric relationship between them can be expressed mathematically: Where: x om and om O m Coordinates on the horizontal plane, x o and o are the coordinates of the origin O, and l is the length of the rope; Take the second-order derivative of time on both sides of the above equation: Where: d x is the projection length of the suspension rope l on the plane zoy, d y is the projection length of the suspension rope l on the plane zox; S3.1.4: Based on the above equations, the state space equation of the crane rope system is obtained: S3.1.5: Based on the swing angle relationship expressed in steps S3.1 and S3.2, the target acceleration of the suspended object in the horizontal x-axis direction Expressed as: Where: is the target acceleration of the suspended object in the x-axis direction; θ x_real-time is the target angle between the suspension rope and its projection on the zoy plane; d x_real-time is the target length of the projection of the lifting rope on the plane zoy, l is the length of the lifting rope, and m is the weight of the object being lifted; S3.1.6: Construct the deflection equation for the suspension rope system: e x =d x -d x_real-time dx is the length of the projection of the rope on the plane zoy, d x_real-time is the target length of the projection of the rope on the plane zoy, when e x When it is 0, the actual length of the rope projected on the plane is the same as the desired control target length, and the design sliding membrane surface equation is: Combined with the state space equation in step S3.4, the following equation is obtained by taking the derivative on both sides of the synovial surface s: make Get the dynamic compensation u ox , the dynamic compensation u ox and symbol controller u x The synovial film controller in the x-axis direction is obtained by combination; the principle of constructing the synovial film controller in the y-axis direction is the same as that of constructing the synovial film controller in the x-axis direction.

4. The control method according to claim 3, further characterized in that: The feasibility of the above-mentioned sliding membrane controller is verified as follows: Set the Lyapunov function to: V = s 2 / 2, and taking the derivative of this equation, we get the following equation: When γ x >0,λ x When >0, the system is stable.

5. The control method according to claim 1, further characterized in that: A three-wheel tension sensor is used to measure the rope tension of the lifting rope; an encoder is used to measure the length of the lifting rope; and a two-dimensional laser displacement sensor is used to measure the angle between the lifting rope and its projection on the plane zoy and the plane zox.

6. A suspension rope anti-slant control system based on acceleration feedback, using the control method described in any one of claims 1 to 5 to control the movement trajectory of the suspension rope; comprising: A lifting assembly, wherein the lifting assembly is mounted on a y-axis moving trolley, and the y-axis driving motor drives the y-axis moving trolley to move, thereby driving the lifting assembly to move; An x-axis moving trolley is driven by an x-axis driving motor to move along the crane frame in the x-axis direction; The y-axis moving trolley is installed on the x-axis moving trolley and is driven by the y-axis driving motor to move along the y-axis direction on the x-axis moving trolley; The lifting assembly includes: a base, a reel, a lifting rope, a three-wheel tension sensor, a two-dimensional laser displacement sensor and an encoder. The base is fixed on a y-axis moving trolley or the base serves as a y-axis moving trolley. The reel is rotatably hingedly supported on the base, the lifting rope is wound on the reel, and the free end of the lifting rope passes through the three-wheel tension sensor, the encoder and the two-dimensional laser displacement sensor in sequence and then hangs down to connect with the hook. A processor, which calculates the thrust of the x-axis drive motor and the y-axis drive motor in real time based on the synovial controller; The controller receives the instruction from the processor to drive the x-axis driving motor and the y-axis driving motor to move.

7. The control system according to claim 6, further characterized in that: The three-wheel tension sensor is installed at one end of the base to measure the tension of the suspension rope; the free end of the suspension rope is hung downward after passing through the three-wheel tension sensor, and the encoder is installed on the side of the three-wheel tension sensor to measure the length of the hanging rope; the two-dimensional laser displacement sensor is installed below the three-wheel tension sensor to measure the deflection displacement data of the suspension rope.

Images