Motion decoupling control method for unmanned tower crane

Abstract

This invention discloses a motion decoupling control method for unmanned tower crane operation, comprising the following steps: 1) system initialization; 2) modeling the construction site environment; 3) low-speed lifting of the hook off the ground; 4) determining whether the hook is off the ground; 5) real-time acquisition of the current position and load information of the tower crane hook; 6) prediction of hook motion; 7) calculation of whether the hook will experience a motion collision; 8) decoupling control of the tower crane's motion speed; 9) determining whether the tower crane is lowering the hook at low speed; 10) determining whether the hook is in position, until the hook reaches the target position. This invention belongs to the field of tower crane automatic control technology. Different motion control strategies are designed based on the different characteristics of the three motions of the tower crane. This unmanned tower crane control strategy fully meets the safety requirements for tower crane hoisting, solves the control problems of large inertia and response lag in tower cranes, and effectively avoids tower crane vibration caused by sudden changes in the tower crane's motion speed.

Description

Technical Field

[0001] This invention belongs to the field of tower crane automatic control technology, and relates to a motion decoupling control method for unmanned tower crane operation. Background Technology

[0002] Tower cranes (hereinafter referred to as tower cranes) are a type of construction machinery used for transporting goods on construction sites. They offer advantages such as ease of use and wide coverage, and are widely used in production construction, cargo loading and unloading, and other engineering fields. Tower cranes are primarily operated manually by experienced operators. Due to the harsh working environment and significant safety responsibilities involved in tower crane operation, recruiting operators is difficult, and labor costs are high. In recent years, with the rapid development of artificial intelligence technology and the application of unmanned docks and unmanned excavators, the unmanned operation of tower cranes has increasingly attracted widespread attention.

[0003] Tower cranes are large-scale lifting machinery with three main motions: slewing, trolley luffing, and hook hoisting. Compared to robotic arms used in ordinary machining, the motion control of tower cranes has the following characteristics: First, the mechanical structure of tower cranes has high inertia and slow response; second, sudden changes in the speed of tower crane movement can not only impact the tower crane structure but also increase the swaying of the load under the steel cables, leading to a collision risk; third, the tower crane's boom structure has a large working range and complex posture in space. Therefore, due to the complexity of the spatial obstacle avoidance control algorithm for unmanned tower cranes, the path planning and path tracking control algorithms used in the automatic control of ordinary robotic arms are not applicable to the unmanned control of tower cranes, making it difficult to achieve high-precision control of the tower crane's operating position. Summary of the Invention

[0004] The purpose of this invention is to provide a motion decoupling control method for unmanned tower cranes, which solves the problem that the path planning of existing technologies is not suitable for motion control of unmanned tower cranes and makes it difficult to achieve high-precision control of the tower crane's operating position.

[0005] The technical solution adopted in this invention is a motion decoupling control method for unmanned tower crane operation, implemented according to the following steps:

[0006] Step 1: System initialization;

[0007] Step 2: Model the construction site environment;

[0008] Step 3: The hook is lifted off the ground at low speed;

[0009] Step 4: Determine if the hook is off the ground;

[0010] Step 5: Obtain the current position and load information of the tower crane hook in real time;

[0011] Step 6: Predict the movement of the hook;

[0012] Step 7: Calculate whether the hook has experienced any movement or collision;

[0013] Step 8: Decoupling control of tower crane movement speed;

[0014] Step 9: Determine if the tower crane is lowering the hook at a low speed;

[0015] Step 10: Determine if the hook is in position until it reaches the target position.

[0016] The beneficial effects of this invention are: 1) By adopting motion decoupling control, different motion control strategies can be designed according to the different characteristics of the three motions of the tower crane; 2) The unmanned tower crane control strategy fully meets the standard requirements for safe hoisting of tower cranes; 3) By adopting a motion speed graded speed regulation method, the control problems of large inertia and response lag of tower cranes are solved, and tower crane vibration caused by sudden changes in tower crane motion speed is effectively avoided. Attached Figure Description

[0017] Figure 1 This is a diagram showing the relationship between the tower crane's movement and the hook's position;

[0018] Figure 2 This is a flowchart of the tower crane motion control method of the present invention;

[0019] Figure 3 This is a schematic diagram of a construction site environment in which the method of this invention is located;

[0020] Figure 4 It is a projection of a construction tower crane and a building on the XOY plane;

[0021] Figure 5 This refers to the hook path planned by the method of the present invention in Example 1;

[0022] Figure 6 This refers to the hook path planned by the method of the present invention in Example 2;

[0023] Figure 7 This is the hook path planned by the method of the present invention in Example 3. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] Based on the current tower crane structure, tower cranes have slewing motion, trolley luffing motion, and hook hoisting motion. These three different motions each have their own characteristics: slewing motion not only has large inertia, but the load also causes uncertainty in slewing inertia, and sudden speed changes during slewing motion can have a significant impact on the tower crane's steel structure; trolley luffing motion control is relatively simple, but changes in luffing speed can cause hook sway; hook hoisting motion is used to control the hook height. According to the structural characteristics of tower cranes, hook hoisting motion generally does not cause hook collisions, but controlling the hook height can assist in hook obstacle avoidance. At the same time, the hook hoisting speed is limited by the load weight of the tower crane. Based on these motion characteristics, this invention provides a motion decoupling control method suitable for unmanned tower crane operation.

[0026] Reference Figure 1 A coordinate system O-XYZ is established with the center of rotation O as the origin, where the XOY plane is the ground coordinate system. According to the working principle of the tower crane, the rotational motion changes the angle between the jib and the X-axis, which is called the tower crane rotation angle θ. t (Hook angle); The luffing motion of the trolley changes the distance between the luffing trolley and the center of the tower crane, which is called the trolley amplitude r. t (Trolley luffing distance); The lifting motion of the hook changes the height of the hook relative to the ground, which is called the hook height h. t (Hook lifting distance).

[0027] Assuming the zero-degree angle of the tower crane's rotation is aligned with the positive direction of the X-axis, the tower crane's rotation angle θ... t , small car amplitude r t and hook height h t This allows us to determine the current coordinate position (x, y) of the hook. t ,y t ,z t )as follows:

[0028]

[0029] Reference Figure 2 The motion decoupling control method for unmanned tower crane operation of the present invention is implemented according to the following steps:

[0030] Step 1: System initialization,

[0031] Assumption: The angular velocity of the rotational motion is set to three levels, namely ω θi i = 1, 2, 3, where ω θ3 The highest gear is used; the variable displacement motion of the trolley is set to three gears, namely v ri i = 1, 2, 3, where v r3 This is the highest gear setting; the lifting speed of the hook is set to five gears, namely v hii = 1, 2, 3, 4, 5, where v h5 This is the highest gear.

[0032] Meanwhile, assuming that the counterclockwise direction during slewing motion is positive, the outward luffing motion of the trolley during luffing motion is positive, and the upward lifting motion of the hook is positive; the current velocities of the tower crane in these three directions are respectively the angular velocities of slewing motion ω θ The speed v of the variable amplitude motion of the trolley r Hook lifting speed v h .

[0033] Step 2: Model the construction site environment.

[0034] Install the load detection sensor, tower crane slewing angle sensor, trolley luffing position sensor and hook height position sensor at the corresponding positions on the tower crane;

[0035] Reference Figure 3 Establish a coordinate system O-XYZ with the center of rotation O as the origin, and the XOY plane as the ground. Within the tower crane's working range, there is a rectangular building M. The center of the projection of building M onto the XOY plane is M0. C (x MC ,y MC The building M has a long side that forms an angle α with the positive X-axis, and its length * width * height is l * w * h, where l ≥ w. An elliptical cylinder is used to fit and model the building M. The expression for the fitted model is:

[0036]

[0037] Where A, B, C, D, E, and F represent the coefficients of the ellipse equation, and H represents the height of the fitted elliptic cylinder, which is equal to the height h of the building M. The function is as follows:

[0038]

[0039] Where e is the eccentricity of the ellipse, e∈(0,1), and in the application scenario of this step, e is taken as 0.8.

[0040] Step 3: The hook is lifted off the ground at low speed.

[0041] See Figure 3 Assume the tower crane hook starts from position A(x) A ,y A ,z A The position B(x) moves to the working surface of the building. B ,y B ,z B ) place;

[0042] According to the tower crane safety operation specifications, when lifting materials, the tower crane should first lift at a low speed. Only after the hook has lifted a certain distance off the ground can the tower crane begin the trolley luffing and slewing movements. Therefore, the parameter for the low-speed lifting of the tower crane hook is: ω θ =0, v r =0, v h =v h1 .

[0043] Step 4: Determine if the hook is off the ground.

[0044] The current hook height h is obtained in real time through the hook height position sensor installed on the tower crane. t ,

[0045] If |h t -z A |≥h g h g To determine the threshold for lifting the hook off the ground, proceed to step 5;

[0046] Otherwise, proceed to step 4;

[0047] Step 5: Obtain the current position and load information of the tower crane hook in real time.

[0048] The current lifting weight L of the tower crane is obtained in real time through relevant sensors installed on the tower crane. t Hook angle θ t , small car amplitude r t and hook height h t The current position (x) of the hook is calculated using equation (1). t ,y t ,z t ).

[0049] Step 6: Predict the movement of the hook.

[0050] Reference Figure 4 It is based on Figure 3 Regarding the projections of the construction tower crane and building M onto the XOY plane, line segment EF represents the projection of the tower crane boom, and the current projected position of the hook is at point C(x). t ,y t The ellipse position represents the obstacle fitting range, and the current hook angle θ can be obtained according to equation (1). t , small car amplitude r t ;

[0051] Assume that the trolley luffing speed of the tower crane is at this time. The angular velocity of the rotational motion is ω θ The magnitude of the tangential linear velocity of the hook is in The velocity of the hook in the XOY plane is the tangential velocity of the hook's rotation. With the variable speed of the car Vector composition, the velocity vector obtained by vector composition See Figure 4 velocity vector This refers to the predicted motion of the hook; velocity vector. model The magnitude of the hook's movement speed, velocity vector The phase angle β is the direction of the hook's velocity, and the expression for the hook's velocity is:

[0052]

[0053] Step 7: Calculate whether the hook has experienced any movement or collision.

[0054] Based on the current position C(x) of the hook obtained in step 5 t ,y t ,z t If z satisfies t >(h+h g h is the building height. g If a threshold is set for determining whether the hook is off the ground, then the current hook movement will not collide with obstacles.

[0055] Otherwise, the velocity vector of the hook motion in the XOY plane can be obtained according to equation (4). The equation of the straight line:

[0056] y = tanβ·x + (y t -tanβ·x t (5)

[0057] Combined velocity vector The intersection point P(x) is calculated by combining the equation of the straight line (5) with the equation of the ellipse fitted to the obstacle (2). p ,y p If there is an intersection point, the movement of the tower crane hook will be related to the building at point M(x). p ,y p ,z t A collision will occur if a collision does not occur otherwise.

[0058] By combining equations (2) and (5), the intersection point P(x) is calculated. p ,y p Coordinates of )

[0059]

[0060] Where a, b, and c represent the parameters in equation (6), and their expressions are as follows:

[0061]

[0062] For simplicity, a, b, and c are introduced. In equation (7), A, B, C, D, E, and F represent the coefficients of the ellipse in equation (2), respectively.

[0063] Then, calculate the angle θ at point P in the XOY plane according to equation (1). p And the distance from the center of rotation; if the tower crane hook will not collide with the obstacle, then the angle θ can be inferred. P =∞, distance r P =∞.

[0064] Step 8: Decoupling control of tower crane movement speed.

[0065] This step involves real-time control of the tower crane's three movement speeds to achieve path planning and tracking of the tower crane hook.

[0066] The current angle θ of the tower crane hook is obtained from step 5. t , small car amplitude r t and hook height h t ;

[0067] The target position B(x) is obtained from equation (1). B ,y B ,z B ) angle θ B Amplitude r B and height h B ;

[0068] The collision point P(x) of the tower crane's movement is obtained from steps 6 and 7 respectively. p ,y p ) angle θ p Amplitude r p ;

[0069] Based on the relative positions of the hook's current position, the target position, and the point of collision, the tower crane's three motion speeds are decoupled and controlled, as detailed below:

[0070] 8.1) Controlling the angular velocity ω of the rotational motion θ ,

[0071] 8.1.1) Determine the direction of rotation.

[0072] Based on the current angle θ of the tower crane hook t and the angle θ of the target position B The following judgments can be made:

[0073] If 0 < θ t <180, and θt <θ B ≤(θ t If the value is +180, then the tower crane is considered to be rotating counterclockwise, and the angular velocity of its rotational motion is positive.

[0074] If 0 < θ t <180, and (θ) t +180)<θ B or θ t ≥θ B If the tower crane rotates clockwise, then the angular velocity of its rotational motion is considered negative.

[0075] If 180 < θ t ≤360, and θ B ≤(θ t -180), θ B <θ t If the tower crane rotates counterclockwise, then the angular velocity of its rotational motion is considered to be negative.

[0076] If 180 < θ t ≤360, and θ B >(θ t -180) or θ t ≤θ B If the tower crane rotates clockwise, then the angular velocity of its rotational motion is considered negative.

[0077] 8.1.2) Determine the magnitude of the rotational speed.

[0078] Definition: The reference angle for controlling the angular velocity of the tower crane's slewing motion is θ. g The angular velocity control angle threshold is θ. i i = 1, 2, 3, which correspond to the three rotational speeds ω of the tower crane, respectively. θi i = 1, 2, 3; the rotational motion state flag is F θ ;

[0079] If the current angular velocity of the tower crane's rotation is positive (counterclockwise), and θ t <θ p ≤θ B Then θ is considered g =θ p Otherwise, θ is considered... g =θ B ;

[0080] If the current angular velocity of the tower crane's rotation is negative (clockwise), and θ p >θ B θ p >θ t Then we consider θ g =θ p Otherwise, θ is considered... g =θB ;

[0081] 8.1.3) The tower crane slewing motion angular velocity control strategy is as follows:

[0082] If |θ t -θ g |<θ1 and θ g =θ p θ1 is the threshold angle for stopping the tower crane's slewing, then the current angular velocity of slewing motion ω is set. θ =0, rotational motion status flag F θ =1 indicates that the rotational motion stops in order to avoid the obstacle;

[0083] If |θ t -θ g |<θ1 and θ g =θ B Then set the current rotational angular velocity ω. θ =0, rotational motion status flag F θ =0 indicates that the angle of the hook reaches the target position and the rotation stops;

[0084] If θ1 <|θ t -θ g |≤θ2, where θ2 is the angular velocity ω of the tower crane's rotational motion. θ1 The corresponding angle threshold is used to set the current rotational angular velocity ω. θ =ω θ1 Rotational motion status flag F θ =2 indicates that the tower crane continues to rotate;

[0085] If θ2 <|θ t -θ g |≤θ3, where θ3 is the angular velocity ω of the tower crane's rotational motion. θ2 The corresponding angle threshold is then used to set the current rotational angular velocity ω. θ =ω θ2 Rotational motion status flag F θ =2 indicates that the tower crane continues to rotate;

[0086] If θ3 <|θ t -θ g | Then set the current rotational angular velocity ω θ =ω θ3 Rotational motion status flag F θ =2 indicates that the tower crane continues to rotate;

[0087] 8.2) Control the speed v of the trolley's variable amplitude motion. r ,

[0088] 8.2.1) Determine the direction of the trolley's variable amplitude motion velocity.

[0089] According to the current luffing distance r of the tower crane hook t and the luffing distance r of the target position B , if r t >r B , then the trolley luffs inwards and the luffing speed of the trolley is negative; if r t ≤r B , then the trolley luffs outwards and the luffing speed of the trolley is positive;

[0090] 8.2.2) Determine the magnitude of the luffing speed of the trolley

[0091] Definition: The reference distance for controlling the luffing speed of the tower crane trolley is r g ; the threshold of the distance for dividing the luffing speed of the trolley into gears is r i , i = 1, 2, 3, corresponding to the three luffing speeds v of the tower crane trolley ri , i = 1, 2, 3, and the luffing state flag of the trolley is F r ;

[0092] If the current luffing speed of the tower crane trolley is positive (i.e., the trolley luffs outwards) and r < r p ≤r B , then it is considered that r g =r p ; otherwise it is considered that r g =r B ;

[0093] If the current luffing speed of the tower crane trolley is negative (i.e., the trolley luffs inwards) and r B <r p <r, then it is considered that r g =r p ; otherwise it is considered that r g =r B ;

[0094] 8.2.3) The control strategy for the luffing speed of the tower crane trolley is as follows:

[0095] If |r t -r g |≤r1 and r g =r p , then set the current luffing speed v of the trolley r =0, and the luffing state flag F of the trolley r =1, indicating that the luffing of the trolley stops for obstacle avoidance;

[0096] If |r t -r g |≤r1 and r g =r BIf r1 is the distance threshold for the tower crane trolley to stop its luffing motion, then the current trolley luffing speed v is set. r =0, the trolley's variable amplitude motion status flag F r =0 indicates that the hook amplitude has reached the target position and the luffing motion has stopped;

[0097] If r1 <|r t -r g |≤r2, where r2 is the luffing speed v of the tower crane trolley. r1 The corresponding distance threshold is used to set the current variable displacement speed v of the vehicle. r =v r1 The indicator for the variable amplitude motion of the small car is F. r =2 indicates that the tower crane continues the luffing motion of the trolley;

[0098] If r2 <|r t -r g |≤r3, where r3 is the tower crane's luffing speed v r2 The corresponding distance threshold is used to set the current variable displacement speed v of the vehicle. r =v r2 The indicator for the variable amplitude motion of the small car is F. r =2 indicates that the tower crane continues the luffing motion of the trolley;

[0099] If r3 <|r t -r g | Then set the current variable displacement speed v of the trolley. r =v r3 The indicator for the variable amplitude motion of the small car is F. r =2 indicates that the tower crane continues the luffing motion of the trolley;

[0100] 8.3) Control the hoisting speed v r ,

[0101] 8.3.1) Determine the direction of hoisting motion.

[0102] Assuming that before the hook reaches the target position, during obstacle avoidance and hoisting, the hook's lifting direction is upward;

[0103] 8.3.2) Determine the magnitude of the lifting motion speed.

[0104] According to the working principle of tower cranes, the lifting speed of tower cranes is related to the weight of the crane. At the same time, considering that there is no risk of collision with the hook during the lifting process, the lifting process can be used to avoid obstacles. Therefore, the control of the lifting speed of tower cranes depends not only on the current weight of the crane, but also on the collision of the hook.

[0105] If F θ =1 and F r=1 indicates that the tower crane's current slewing motion and trolley luffing motion are both in the obstacle avoidance stop state, but the tower crane's slewing and luffing have not reached the target position. At this time, hoisting speed control strategy one is adopted.

[0106] Otherwise, it means that the tower crane continues to rotate or the trolley continues to luff, or the tower crane's rotation angle and the trolley's luffing position have both reached the target position and are in a stopped state. In this case, hoisting speed control strategy two is adopted.

[0107] Definition: The lifting speed control threshold for tower cranes is L. i i = 1, 2, 3, 4, 5, corresponding to the five speed settings of the tower crane's hoisting. hi If i = 1, 2, 3, 4, 5, then we have the following two strategies:

[0108] Lifting speed control strategy one:

[0109] If L t If L5 is less than or equal to L5, then set the current lifting speed v. h =v h5 Where L5 is the tower crane's lifting speed v h5 The corresponding lifting weight threshold;

[0110] If L5 <L t If L4 is less than or equal to 4, then set the current lifting speed v. h =v h4 Where L4 is the tower crane's lifting speed v h4 The corresponding lifting weight threshold;

[0111] If L4 <L t If L3 is less than or equal to L3, then set the current lifting speed v. h =v h3 Where L3 is the tower crane's lifting speed v h3 The corresponding lifting weight threshold;

[0112] If L3 <L t If L2 is less than or equal to L2, then set the current lifting speed v. h =v h2 Where L2 is the tower crane's lifting speed v h2 The corresponding lifting weight threshold;

[0113] If L2 <L t If ≤L1, then set the current lifting speed v. h =v h1 L2 represents the tower crane's lifting speed v. h1 The corresponding lifting weight threshold;

[0114] If L1 <L t Tower crane overload, lifting speed vh =0.

[0115] Lifting speed control strategy two:

[0116] If L t If L5 is less than or equal to L5, then set the current lifting speed v. h =v h5 Where L5 is the tower crane's lifting speed v h5 The corresponding lifting weight threshold;

[0117] If L5 <L t If L4 is less than or equal to 4, then set the current lifting speed v. h =v h4 Where L4 is the tower crane's lifting speed v h4 The corresponding lifting weight threshold;

[0118] If L4 <L t If L3 is less than or equal to L3, then set the current lifting speed v. h =v h3 Where L3 is the tower crane's lifting speed v h3 The corresponding lifting weight threshold;

[0119] If L3 <L t If L2 is less than or equal to L2, then set the current lifting speed v. h =v h2 Where L2 is the tower crane's lifting speed v h2 The corresponding lifting weight threshold;

[0120] If L2 <L t If ≤L1, then set the current lifting speed v. h =v h1 L2 represents the tower crane's lifting speed v. h1 The corresponding lifting weight threshold;

[0121] If L1 <L t Tower crane overload, or (h B +h g ) <h t Once the hook reaches above the target position, set the current lifting speed v of the tower crane. h =0.

[0122] Step 9: Determine if the tower crane is lowering the hook at a low speed.

[0123] Based on the current angle θ of the tower crane hook obtained in step 5 t , small car amplitude r t and hook height h t ,

[0124] If |θ t -θB |<θ1、|r t -r B | <r1、(h B +h g ) <h t This indicates that the hook has reached its current position. At this point, the tower crane will lower the hook at a low speed to position it. The control speed for the low-speed hook lowering movement is: v h =-v h1 ω θ =0, r h =0, proceed to step 10;

[0125] Otherwise, return to step 5 to reacquire the current position and perform motion estimation, collision calculation, and motion speed control.

[0126] Step 10: Determine if the hook is in place.

[0127] The current hook height h of the tower crane is obtained through the hook height position sensor. t If |h t -z B | h =0; End autopilot control;

[0128] Otherwise, repeat step 10 until the hook reaches the target position.

[0129] Experimental verification:

[0130] A tower crane CCT331 is installed at a construction site. The boom length of the tower crane is 70m. Based on the performance of the tower crane, three speed levels and corresponding angle or distance thresholds are set for the tower crane, as shown in Tables 1, 2 and 3. The unit of angular velocity is rpm, the unit of angle is degrees, the unit of speed is m / min, the unit of distance is m, and the unit of lifting weight is t.

[0131] Table 1. Tower crane slewing angular velocity and corresponding angle thresholds

[0132]

[0133]

[0134] Table 2. Tower Crane Trolley Luffing Speed ​​and Corresponding Distance Thresholds

[0135] <![CDATA[v ri ]]> 0 8 32 50 <![CDATA[r i ]]> 1 6 20 >20

[0136] Table 3. Tower Crane Lifting Speed ​​and Corresponding Lifting Weight

[0137] <![CDATA[v h ]]> 30 39 56 97 110 <![CDATA[L i ]]> 8 6 4 2 1.7 ​

[0138] Example 1

[0139] See Figure 5 During the initial foundation construction, the tower crane, with a height of 30 meters, needs to lift a 1.9-ton steel bar from location A(24,-9,0) in the ground steel bar material area to point B(-1.5,16,0) on the building's working surface. A load detection sensor, a tower crane slewing angle sensor, a trolley luffing position sensor, and a hook height position sensor are installed on the tower crane to obtain the real-time position (x, y) of the tower crane hook. t ,y t ,z t ).

[0140] The motion decoupling control method for unmanned tower crane operation according to the present invention is implemented in conjunction with Tables 1, 2 and 3, and is briefly described below:

[0141] Let h be the threshold for determining whether the hook is off the ground. g =5m, firstly, the hook moves at low speed (from Table 3, first gear v) h =8m / min) Lifting, slewing, and luffing motions stop, ω θ =0, v r =0; When the tower crane hook reaches a low-speed lifting height of 5 meters, that is, when the hook reaches... Figure 5 The position is A1(24,-9,5); then, based on the current position of the hook and the target position, step 7 confirms that the tower crane hook will not collide with the obstacle; at this time, the reference angle θ for controlling the angular velocity of the tower crane's rotation is... g =120°, reference distance r for tower crane trolley luffing speed control g =10m, tower crane hook height h t >(z B +h g Therefore, according to the tower crane motion decoupling control strategy in step 8, the current speeds of the three movements of the tower crane can be obtained from Tables 1, 2, and 3 as ω. θ =0.78r / min, v r =32m / min, v h =0; the tower crane moves at this speed to above the target position, i.e., position A2 (-1.4, 15.8, 5); finally, according to step 9 and Table 3, the tower crane will move at the lowest gear (gear 1 v) h The crane will lower the hook at a speed of -8m / min until it reaches the target point B, thus completing the unmanned operation control of the tower crane.

[0142] exist Figure 5 In the diagram, "*" represents each point in the movement of the hook, and the line formed by "*" represents the path of the hook from point A to point B.

[0143] Example 2

[0144] See Figure 6 A rectangular building needs to be constructed at the construction site. The center of the building on the XOY plane is (10, 14); the length and width of the building are (40*15). The equation of the ellipse obtained by projecting the elliptical cylindrical model of the building onto the XOY plane is:

[0145] 256x 2 +0xy+713y 2 -5120x-19964y-17609=0

[0146] When the building height reaches 30 meters and the tower crane height is 40 meters, the tower crane needs to lift a 1.9-ton steel bar from steel bar material area A (24, -9, 0) to point B (-1.5, 16, 30) on the building's working surface. The tower crane is equipped with a load detection sensor, a tower crane slewing angle sensor, a trolley luffing position sensor, and a hook height position sensor to obtain the current position (x) of the tower crane hook in real time. t ,y t ,z t ).

[0147] The motion decoupling control method for unmanned tower crane operation according to the present invention is implemented as follows:

[0148] Let h be the threshold for determining whether the hook is off the ground. g =5m, firstly, the hook moves at low speed (from Table 3, the first gear, i.e., v). h =8m / min) Lifting, slewing, and luffing motions stop, ω θ =0, v r =0; When the tower crane hook reaches a height of 5 meters, that is, when the hook reaches... Figure 6 The position A1(24,-9,5) in the middle;

[0149] Next, based on the current position of the hook and the target position, it can be determined that there is no collision between the tower crane hook and the building. At this point, the reference angle θ for controlling the angular velocity of the tower crane's rotation is set. g =120°, reference distance r for controlling the speed of the trolley's variable amplitude motion. g =10m, tower crane hook height h t >(z B +h g Given that the tower crane is currently lifting 1.9 tons, according to the decoupling control strategy for the tower crane's movement speed in step 8, the current three movement speeds of the tower crane, controlled by Tables 1, 2, and 3, are ω. θ =0.78r / min, v r =32m / min, v h=97m / min; the tower crane moves at this speed to Figure 6 The location A2 (22.7, -0.2, 11.8) is shown;

[0150] At position A2, step 7 is based on the current velocity vector of the hook. The collision point P(21.5, 2.3) is calculated using the building equations; at this point, the reference angle θ for controlling the tower crane's slewing motion angular velocity is... g =4°, reference distance r for tower crane trolley luffing speed control g =0.8m, tower crane hook height h t <(z B +h g Therefore, according to the tower crane speed decoupling control strategy in step 8, the current three speeds of the tower crane are controlled by Tables 1, 2, and 3 as ω. θ =0 r / min, v r =0m / min, v h =97m / min; the tower crane moves at this speed to Figure 6 The position A3 (22.7, -0.2, 35.2) is shown in the diagram;

[0151] At position A3, by sequentially repeating steps 5, 6, and 7, the current direction of motion of the hook can be determined and confirmed. There is no risk of collision with the building. At this time, the reference angle θ for controlling the angular velocity of the tower crane's slewing motion is... g =98°, reference distance r for tower crane trolley luffing speed control g =7.5m, tower crane hook height h t >(z B +h g According to step 8, combined with Tables 1, 2, and 3, the current three movement speeds of the tower crane are ω. θ =0.78r / min, v r =32m / min, v h =0 m / min; the tower crane moves at this speed to Figure 6 The position A4 (-1.5, 15.9, 35.2) is shown in the diagram;

[0152] When the hook moves to position A4, which is directly above the target point B, according to step 9 and Table 3, the tower crane's slewing and luffing movements stop. θ =0 r / min, v r =0m / min; the tower crane will operate at the lowest speed (speed 1 v) h The hook is lowered at a speed of -8 m / min until it reaches the target point B.

[0153] Figure 6In the diagram, "*" represents each point in the movement of the hook, and the line formed by "*" represents the path of the hook from point A to point B.

[0154] Example 3

[0155] See Figure 7 The center of a rectangular building under construction on the XOY plane is (10, 14); the building's length and width are (40 * 15); when the building's construction height reaches h = 30 meters, and the tower crane's height is 40 meters, the tower crane needs to lift a 1.9-ton steel bar from steel bar material area A (7.8, -44, 0) to point B (-2.6, 14.7, 30) on the building's working surface. A load detection sensor, a tower crane slewing angle sensor, a trolley luffing position sensor, and a hook height position sensor are installed on the tower crane to obtain the current position of the hook (x, y, y, y) in real time. t ,y t ,z t ).

[0156] The motion decoupling control method for unmanned tower crane operation according to the present invention is implemented as follows:

[0157] By sequentially repeating steps 5, 6, 7, and 8, and finally executing step 9, and combining Tables 1, 2, and 3, we can obtain the path of the hook from the starting position to the target position, as well as the speed change values ​​along the path. Figure 7 The five position points are A1(7.8,-44,5.1), A2(-0.9,-43.1,9.4), A3(-25.3,-24.7,25.5), A4(-30.4,-7.5,35.2), and A5(-3.5,15.4,35.2), which represent the positions where the hook's speed changes during path tracking. Figure 7 In the table, "*" represents each point in the hook's movement, and the line formed by "*" represents the path of the hook from point A to point B. Table 4 gives the speed values ​​of the tower crane hook in the three movements of the six paths (A→A1, A1→A2, A2→A3, A3→A4, A4→A5, A5→B).

[0158] Table 4. Changes in the speed and motion state of the tower crane hook in Example 3

[0159]

[0160]

[0161] The above three embodiments demonstrate that the motion decoupling control method for unmanned tower crane operation of the present invention, combined with the standard requirements for safe hoisting of tower cranes, adopts a graded speed regulation and decoupling control strategy to realize hook path planning and control for unmanned tower crane operation, solves the control problems of large inertia and response lag of tower cranes, and effectively avoids tower crane vibration caused by sudden changes in tower crane motion speed.

Claims

1. A motion decoupling control method for unmanned operation of a tower crane, characterized in that Follow these steps: Step 1: System initialization, the specific process is as follows: Assumption: The angular velocity of the rotational motion is set to three levels, namely... ω θi , i=1,2,3, where ω θ3 The highest gear is used; the variable displacement motion of the trolley is set to three gears, namely... v ri , i=1,2,3, where v r3 The highest gear is used; the lifting speed of the hook is set to five gears, namely: v hi , i=1,2,3,4,5, where v h5 This is the highest gear position; at the same time, it is assumed that the counterclockwise direction during the slewing motion is positive, the outward luffing of the trolley during the luffing motion is positive, and the upward lifting of the hook during the lifting motion is positive. The speed of the current three movement directions of the tower machine is respectively: rotation movement angular velocity ω θ , trolley amplitude movement speed v r , hook lifting speed v h ; Step 2: Model the construction site environment; Step 3: The hook is lifted off the ground at low speed; Step 4: Determine if the hook is off the ground; Step 5: Obtain the current position and load information of the tower crane hook in real time; Step 6: Predict the movement of the hook. The specific process is as follows: Based on the projections of the construction tower crane and building M onto the XOY plane, line segment EF represents the projection of the tower crane boom, and the current projected position of the hook is at point C. x t ,y t The ellipse position represents the obstacle fitting range, and the current hook angle can be obtained according to equation (1). θ t , small car amplitude r t ; Assume that the trolley luffing speed of the tower crane is at this time. The angular velocity of the rotational motion is ω θ The magnitude of the tangential linear velocity of the hook is ,in The velocity of the hook in the XOY plane is the tangential velocity of the hook's rotation. With the variable speed of the car Vector composition, the velocity vector obtained by vector composition velocity vector This refers to the predicted motion of the hook; velocity vector. model The magnitude of the hook's movement speed, velocity vector phase angle β Let the direction of the hook's velocity be denoted by: The expression for the hook's velocity is: (4)； Step 7: Calculate whether the hook has experienced a collision. The specific process is as follows: Based on the current position C of the hook obtained in step 5 ( x t ,y t ,z t If the following conditions are met z t >( h + h g ), h For the building height, h g If a threshold is set for determining whether the hook is off the ground, then the current hook movement will not collide with obstacles. Otherwise, the velocity vector of the hook motion in the XOY plane can be obtained according to equation (4). The equation of the straight line: (5) Combined velocity vector The intersection point P is calculated by combining the equation of the straight line (5) with the equation of the ellipse fitted to the obstacle (2). x p ,y p If there is an intersection point, the tower crane hook movement will be related to the building at point M. x p ,y p ,z t A collision will occur if a collision does not occur otherwise. Solving equations (2) and (5) simultaneously, the coordinates of the intersection point P ( x p ,y p ) are calculated: (6) wherein a, b, c denote the parameters in equation (6), respectively, and are expressed as follows, respectively: (7) In equation (7), A, B, C, D, E, and F represent the coefficients of the ellipse in equation (2), respectively. According to formula (1) to calculate the angle of point P in the X-O-Y plane θ p and the distance from the center of rotation, if the tower crane hook and obstacles will not collide, the angle is inferred , the distance ; Step 8: Decoupling control of tower crane movement speed. The specific process is as follows: Obtaining the current angle of the crane hook from step 5 θ t trolley amplitude r t and hook height h t ; The target position B is obtained from equation (1). x B ,y B ,z B ) angle θ B Amplitude r B and height h B ; The collision point P of the tower crane movement is obtained by step 6, step 7 respectively ( x p ,y p ) of the angle θ p , amplitude r p ; Based on the relative positions of the hook's current position, the target position, and the point of collision, the tower crane's three motion speeds are decoupled and controlled, as detailed below: 8.1) Controlling the angular velocity of the turning movement ω θ , 8.1.1) Determine the direction of rotation; 8.1.2) Determine the magnitude of the rotational speed; 8.1.3) Determine the control strategy for the angular velocity of the tower crane's slewing motion; 8.2) Controlling the trolley luffing speed , 8.2.1) Determine the direction of the trolley's variable amplitude motion velocity; 8.2.2) Determine the magnitude of the trolley's variable amplitude motion speed; 8.2.3) Determine the speed control strategy for the tower crane trolley's luffing motion; 8.3) Controlling the speed of the hoisting motion v r , 8.3.1) Determine the direction of hoisting motion; 8.3.2) Determine the magnitude of the lifting motion speed; Step 9: Determine if the tower crane is lowering the hook at a low speed; Step 10: Determine if the hook is in position until it reaches the target position.

2. The unmanned motion decoupling control method of the tower crane according to claim 1, characterized in that, Step 2, the specific process is as follows: Install the load detection sensor, tower crane slewing angle sensor, trolley luffing position sensor and hook height position sensor on the tower crane respectively; Establish a coordinate system O-XYZ with the center of rotation O as the origin, and the XOY plane as the ground. Within the tower crane's working range, there is a rectangular building M. The center of the projection of building M onto the XOY plane is M0. C ( x MC ,y MC The angle between the long side of building M and the positive X-axis is... α The length * width * height of building M is l * w * h , l ≥ w The building M is modeled using an elliptical cylinder, and the expression of the model is as follows: (2) in, A , B , C , D , E , F Let each of these represent a coefficient of the equation of the ellipse. H This represents the height of the fitted elliptical cylinder, and its value is equal to the height of building M. h The function is as follows: (3) wherein e is the eccentricity of the ellipse.

3. The unmanned motion decoupling control method of the tower crane according to claim 1, characterized in that, Step 3, the specific process is as follows: Assume the tower crane hook starts from position A ( x A ,y A ,z A Position B of the building's working surface. x B ,y B ,z B According to the tower crane safety operation specifications, when lifting materials, the tower crane should first lift at a low speed, and only after the hook has lifted a certain distance off the ground can the tower crane begin the trolley luffing and slewing movements. Therefore, the parameters for the low-speed lifting of the tower crane hook off the ground are: ω θ = 0、 v r = 0、 v h = v h1 .

4. The unmanned motion decoupling control method of tower crane according to claim 1, characterized in that, Step 4, the specific process is as follows: The current hook height is acquired in real time by a hook height position sensor h t , If | h t z A |≥ h g , h g To determine the threshold for lifting the hook off the ground, proceed to step 5; Otherwise, proceed to step 4.

5. The unmanned motion decoupling control method of tower crane according to claim 1, characterized in that, Step 8, the specific process is as follows: Obtaining the current angle of the crane hook from step 5 θ t The trolley amplitude r t And the hook height h t ; The target position B is obtained from equation (1). x B ,y B ,z B ) angle θ B Amplitude r B and height h B ; The collision point P of the tower crane's movement is obtained from steps 6 and 7 respectively. ( x p ,y p ) angle θ p Amplitude r p ; Based on the relative positions of the hook's current position, the target position, and the point of collision, the tower crane's three motion speeds are decoupled and controlled, as detailed below: 8.1) Controlling the angular velocity of the turning movement ω θ , 8.1.1) Determine the direction of rotation. According to the current angle of the tower crane hook θ t and the angle of the target position θ B the following is determined: If 0 θ t <180, and θ t <180, and θ B <180, and θ t +180), the tower machine is considered to rotate counterclockwise, and the rotation angular velocity is positive. If 0 θ t <180, and ( θ t +180) θ B or θ t ≥ θ B the tower machine is considered to rotate clockwise, and the rotation angular velocity is negative; If 180 < θ t ≤ 360, and θ B ≤ ( θ t 180), θ B < θ t If the tower crane rotates counterclockwise, then the angular velocity of its rotational motion is considered negative. If 180 < θ t ≤ 360, and θ B >( θ t 180) or θ t ≤ θ B If the tower crane rotates clockwise, then the angular velocity of its rotational motion is considered negative. 8.1.2) Determine the magnitude of the rotational speed. Definition: The reference angle for controlling the angular velocity of the tower crane's slewing motion is... θ g The angular velocity step-by-step control angle threshold is θ i , i =1, 2, 3, which correspond to the three rotational speeds of the tower crane, respectively. ω θi , i =1,2,3; Rotational motion status flags are: F θ ; If the current rotation angular velocity of the tower machine is positive, and θ t θ p ≤ θ B , it is considered that θ g = θ p ; otherwise, it is considered that θ g = θ B ;​ If the current slewing angular velocity of the tower crane is negative, and θ p > θ B 、 θ p > θ t it is considered that θ g = θ p ; otherwise, it is considered that θ g = θ B ; 8.1.3) The tower crane slewing motion angular velocity control strategy is as follows: If | θ t θ g |< θ 1 and θ g = θ p , θ If 1 is the threshold angle for stopping the tower crane's slewing, then the current slewing angular velocity is set. ω θ =0, rotary motion status flag F θ = 1 indicates that the rotation stopped in order to avoid an obstacle; If | θ t θ g |< θ 1 and θ g = θ B Then set the current rotational angular velocity. ω θ =0, rotary motion status flag F θ = 0 indicates that the angle of the hook reaches the target position, and the rotation stops; if θ 1<| θ t θ g |≤ θ 2, θ 2 represents the angular velocity of the tower crane's slewing motion. ω θ1 The corresponding angle threshold is used to set the current rotational angular velocity. ω θ =ω θ1 Rotational motion status indicator F θ = 2 indicates that the tower crane continues to rotate; if θ 2<| θ t θ g |≤ θ 3, θ 3 represents the angular velocity of the tower crane's slewing motion. ω θ2 The corresponding angle threshold is then used to set the current rotational angular velocity. ω θ =ω θ2 Rotational motion status indicator F θ = 2 indicates that the tower crane continues to rotate; if θ 3<| θ t θ g | Then set the current rotational angular velocity. ω θ =ω θ3 Rotational motion status indicator F θ = 2 indicates that the tower crane continues to rotate; 8.2) Controlling the trolley luffing speed , 8.2.1) Determine the direction of the trolley's variable amplitude motion velocity. Based on the current luffing distance of the tower crane hook r t and the amplitude range of the target location r B ,if r t > r B If the trolley moves inward, the speed of the trolley's inward movement will be negative; if r t ≤ r B If the trolley moves outwards, the speed of the trolley's outward movement is positive. 8.2.2) Determine the magnitude of the trolley's variable amplitude motion speed. Definition: The reference distance for controlling the luffing speed of the tower crane trolley is... r g The threshold distance for the variable-speed control of the trolley is... r i , i =1,2,3, corresponding to the luffing speeds of the three trolleys of the tower crane. v ri , i =1,2,3, the trolley's variable amplitude motion status flag is: F r ; If the current tower crane trolley luffing speed is positive, meaning the trolley is luffing outwards, and r < r p ≤ r B Then it is believed r g = r p Otherwise, it is considered r g = r B ; If the current luffing speed of the tower crane trolley is negative, that is, the trolley is luffing inward, and r B < r p < r Then it is believed r g = r p Otherwise, it is considered r g = r B ; 8.2.3) The tower crane trolley luffing motion speed control strategy is as follows: If | r t r g |≤ r 1 and r g = r p Then set the current trolley's variable amplitude speed. v r =0, indicating the variable amplitude motion status of the trolley. F r =1 indicates that the car stopped its amplitude change motion in order to avoid the obstacle; If | r t r g |≤ r 1 and r g = r B , r 1 represents the distance threshold at which the tower crane trolley stops its luffing motion; therefore, the current trolley luffing speed is set. v r =0, indicating the variable amplitude motion status of the trolley. F r =0 indicates that the hook amplitude has reached the target position and the luffing motion has stopped; if r 1<| r t r g |≤ r 2, r 2 represents the luffing speed of the tower crane trolley. v r1 The corresponding distance threshold is used to set the current trolley's variable amplitude speed. v r = v r1 Small car variable amplitude motion status indicator F r =2 indicates that the tower crane continues the luffing motion of the trolley; if r 2<| r t r g |≤ r 3, r 3 represents the tower crane's luffing speed. v r2 The corresponding distance threshold is used to set the current trolley's variable amplitude speed. v r = v r2 Small car variable amplitude motion status indicator F r =2 indicates that the tower crane continues the luffing motion of the trolley; if r 3<| r t r g | Then set the current trolley's variable amplitude speed. v r = v r3 Small car variable amplitude motion status indicator F r =2 indicates that the tower crane continues the luffing motion of the trolley; 8.3) Control the hoisting speed v r , 8.3.1) Determine the direction of hoisting motion. Assuming that before the hook reaches the target position, during obstacle avoidance and hoisting, the hook's lifting direction is upward; 8.3.2) Determine the magnitude of the lifting motion speed. if F θ =1 and F r =1 indicates that the tower crane's current slewing and luffing movements are both in an obstacle avoidance stop state, but the tower crane's slewing and luffing have not reached the target position. At this time, hoisting speed control strategy one is adopted. Otherwise, it means that the tower crane continues to rotate or the trolley continues to luff, or the tower crane's rotation angle and the trolley's luffing position have both reached the target position and are in a stopped state. In this case, hoisting speed control strategy two is adopted. Definition: The lifting speed control threshold for tower cranes is defined as follows: L i , i =1, 2, 3, 4, 5, corresponding to the five speed settings for tower crane lifting. v hi , i If the sum is 1, 2, 3, 4, 5, then there are two strategies: Lifting speed control strategy one: if L t ≤ L 5. Set the current lifting speed. v h = v h5 ,in, tower crane hoisting movement speed v h5 a corresponding load threshold if L 5< L t ≤ L 4. Then set the current lifting speed. v h = v h4 ,in, L 4 represents the tower crane's lifting speed. v h4 The corresponding lifting weight threshold; if L 4< L t ≤ L 3. Set the current lifting speed. v h = v h3 ,in, L 3 represents the tower crane's lifting speed. v h3 The corresponding lifting weight threshold; if L 3< L t ≤ L 2. Then set the current lifting speed. v h = v h2 ,in, Tower crane lifting speed v h2 The corresponding lifting weight threshold; if L 2< L t ≤ L 1. Set the current lifting speed. v h = v h1 , Tower crane lifting speed v h1 The corresponding lifting weight threshold; if L 1< L t Tower crane overload, lifting speed v h =0; Lifting speed control strategy two: if L t ≤ L 5. Set the current lifting speed. v h = v h5 ,in, Tower crane lifting speed v h5 The corresponding lifting weight threshold; if L 5< L t ≤ L 4. Then set the current lifting speed. v h = v h4 ,in, L 4 represents the tower crane's lifting speed. v h4 The corresponding lifting weight threshold; if L 4< L t ≤ L 3. Then set the current lifting speed. v h = v h3 ,in, L 3 represents the tower crane's lifting speed. v h3 The corresponding lifting weight threshold; if L 3< L t ≤ L 2. Then set the current lifting speed. v h = v h2 ,in, Tower crane lifting speed v h2 The corresponding lifting weight threshold; if L 2< L t ≤ L 1. Set the current lifting speed. v h = v h1 , Tower crane lifting speed v h1 The corresponding lifting weight threshold; if L 1< L t Tower crane overload, or ( h B + h g )< h t Once the hook reaches above the target position, set the current lifting speed of the tower crane. v h =0.

6. The motion decoupling control method for unmanned tower crane operation according to claim 1, characterized in that, Step 9 involves the following steps: Based on the current angle of the tower crane hook obtained in step 5 θ t , small car amplitude r t and hook height h t , If | θ t – θ B |< θ 1、| r t – r B |< r 1. ( h B + h g )< h t This indicates that the hook has reached its current position. At this point, the tower crane will lower the hook at a low speed to position it. The controlled speed for the low-speed hook lowering movement is: v h =– v h1 , ω θ = 0、 r h =0, proceed to step 10; Otherwise, return to step 5 to reacquire the current position and perform motion estimation, collision calculation, and motion speed control.

7. The unmanned motion decoupling control method of tower crane according to claim 1, characterized in that, In step 10, the specific process is: The current hook height of the tower crane is obtained through a hook height position sensor. h t If | h t – z B |< h 1. Then it is assumed that the hook has reached the target position, and the setting is... v h =0; End automatic driving control; Otherwise, the loop is executed in step 10 until the hook reaches the target position.

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