CN110228754A - A kind of industrial overhead crane control method and system of adaptive speed planning - Google Patents

Abstract

The invention discloses an adaptive speed planning industrial crane control method and system. Under the given acceleration and maximum speed limit conditions, the bridge crane motion track is planned online, and the crane multi-pulse speed planning is proposed according to the motion distance calculation model. The pulse number adaptive planning of curve and speed can realize smaller swing angle and higher positioning accuracy in the process of crane transporting items without adding offline optimization calculation, which greatly improves the safety of crane transporting items in industrial production. Reliability and work efficiency. The industrial crane control method and system of the adaptive speed planning mainly include a PLC controller (1), an angle measuring instrument (2), a laser range finder (3), a frequency converter (4), an AC asynchronous motor (5), Crane (6) and upper computer (7) moving along the beam direction.

Description

An industrial crane control method and system for adaptive speed planning

technical field

The invention relates to a high-performance anti-sway positioning method for underactuated industrial-grade bridge cranes. Based on the adaptive speed planning method, under the given acceleration and maximum speed limit conditions, the method of online calculation of the anti-sway motion trajectory of the industrial-grade bridge crane.

Background technique

With the development of global industry and the expansion of production scale, the role of overhead crane in industrial production is increasing day by day. Overhead crane is an important heavy loading and unloading equipment, which is widely used in various industrial sites. However, the overhead crane will inevitably sway during the hoisting process. Therefore, it is of great significance to study the control and elimination of the sway of the bridge crane during hoisting and achieve precise positioning, which is of great significance for improving the operation efficiency, handling accuracy and industrial control automation of industrial sites.

The overhead crane always inevitably causes the swing of the suspended object during the hoisting process. It usually requires a very skilled overhead crane operator to manually control the swing of the suspended object, which is the most commonly used method at present. The swing of the hanging object will accelerate the mechanical wear, increase the transit time of the hanging object, and even cause safety accidents. Mechanical anti-sway needs to increase the weight of mechanical equipment and the cost is high. It is limited in some occasions with high size requirements, which is not conducive to the lightweight development of lifting equipment. At present, new manufacturing equipment is rarely used. Therefore, more attention has been paid to anti-sway control by controlling the running track of the crane through various algorithms. The anti-sway positioning control can automatically eliminate the sway of the hanging object during operation, and complete the transfer of the hanging object faster, especially with An automatic industrial-grade overhead crane with positioning function, the anti-sway system can make the operation of the overhead crane more efficient and safer. Cranes on industrial sites need to travel different distances. It is very necessary to provide corresponding speed planning for the uncertainty of the target distance. This patent provides a speed planning anti-sway control method and system, which can effectively reduce the overhead of overhead cranes. Sway in the working process and achieve ideal positioning accuracy.

Contents of the invention

Technical problem: The purpose of the present invention is to provide a control method and system for industrial cranes with adaptive speed planning, aiming at the swinging phenomenon of heavy objects caused by the inertia of steel ropes during the rotation, handling and braking of cranes, which will seriously affect the handling efficiency , and even cause hidden dangers to ground workers. The present invention proposes a high-performance anti-sway positioning method for underactuated industrial-grade bridge cranes. Controlling the anti-sway during the handling process through adaptive speed planning is simple and easy to operate, and does not require offline optimization. , improve work efficiency, and meet industrial-grade requirements.

Technical solution: The present invention is based on the adaptive speed planning industrial crane anti-sway control method and system. First, the kinematics model and the anti-sway control model of the crane system are established based on the Lagrange equation, and the adaptive speed planning uses multi-stage acceleration and deceleration control The algorithm makes the crane run according to the planned speed curve, so as to obtain a stable anti-sway effect. The maximum operating speed of the set crane is divided into k gears, the kth gear is the highest speed, and the first gear is the lowest speed. The adaptive speed planning is divided into specific points for the following steps:

Step 1: Calculate the target distance (Δx=|x ₂ -x ₁ |) from the current position x ₁ and the target position x ₂ , and set the maximum speed v _n of the crane equal to the kth gear speed of the crane, according to the formula Where a is the set acceleration of the crane, T is the simple pendulum cycle of the crane, and the number of acceleration and deceleration steps n is calculated;

Step 2: Determine whether the current number of acceleration and deceleration steps n is greater than or equal to 2, if n is greater than or equal to 2, continue to step 3, if n is less than 2, then reduce the final speed v _n of the crane by one gear, go to step 1, and recalculate n;

Step 3: In the initial acceleration stage, plan the velocity curve and acceleration displacement in the acceleration stage, accelerate from the initial velocity v ₀ (0m/s, static state) to velocity v ₁ with acceleration a (system setting), and maintain at the current velocity v ₁ Moving at a constant speed for a period of time t _s , then accelerating from speed v ₁ to speed v ₂ with acceleration a, and maintaining a constant speed at the current speed v ₂ for a period of time t _s , according to this rule, accelerating n times to reach the target speed v _n , every time The velocities after the second acceleration are respectively v ₁ , v ₂ ... v _n , and the velocity curve and displacement in the acceleration stage are obtained;

Step 4: Stop the deceleration phase, plan the speed curve and deceleration displacement in the deceleration phase, decelerate from the initial speed v _n to the speed v _n-1 with acceleration-a, and maintain a constant speed t _s at the current speed v _n-1 , Then decelerate from speed v _n-1 to speed v _n-2 with acceleration-a, and keep moving at a constant speed for a period of time t _s at the current speed v _n-2 . According to this rule, after n times of deceleration, the speed is 0m/s. The speeds after the second deceleration are v _n-1 ... v ₂ , v ₁ , 0 respectively, and the speed curve and displacement in the deceleration stage are obtained;

Step 5: Calculate the time t _r used in the constant velocity stage from the target distance, the displacement in the acceleration stage, the displacement in the deceleration stage and the velocity v _n , if t _r is greater than zero, then get the velocity curve and displacement in the constant velocity stage and go to step 6, if t _r If it is less than zero, subtract 1 from the number of acceleration and deceleration stages n, and then go to step 2;

Step 6: Output the adaptive speed planning curve of the crane.

According to the analysis of the crane system model, the setting of v ₁ , v ₂ ... v _n speed values and t _s time values can achieve stable anti-sway, l is the length of the rope, g is the acceleration of gravity, and the period of the simple pendulum The settings are as follows:

The industrial crane control method and system of a kind of adaptive speed planning, the device mainly includes: PLC controller (1), angle measuring instrument (2), laser distance measuring instrument (3), frequency converter (4), AC asynchronous motor (5), a crane (6) moving along the direction of the beam, and a host computer (7), the PLC controller (1) and host computer (6) adopt the modules in the DCS system independently developed by Keyuan Company , The angle measuring instrument (2) adopts the product of Saiteke Company, and the laser rangefinder (3) adopts the product of SICK Company.

The control system algorithm of industrial crane anti-swing based on adaptive speed planning is realized through the configuration software of the upper computer (7) in the DCS system, and its output is connected with the input of the PLC controller (1) for downloading the program into the PLC The controller (1), the output of the PLC controller (1) is connected to the input of the frequency converter (4), so as to realize the control of the frequency converter (4) by the PLC controller (1), and the AC asynchronous motor is controlled by the frequency converter (4) The speed of (5) is driven by the AC asynchronous motor (5) and the crane (5) that can move along the beam direction moves according to the planned speed curve, and the crane can be moved by the angle measuring instrument (2) and the laser range finder (3) The real-time angle and real-time position are transmitted to the upper computer (6) detection software and real-time database system of the DCS system to monitor the speed curve and real-time angle curve of the crane.

The flowchart of adaptive speed planning is shown in Figure 3. The planned speed curve is finally output, and the speed value is directly transmitted to the frequency converter of the crane motor.

Beneficial effects: the control method provided by the present invention adopts the control algorithm of adaptive speed planning, which can adapt to different target distances to plan corresponding speed curves, give motion trajectories, realize the suppression of load swing when the crane is working, and can meet the position accuracy Require.

Description of drawings

Figure 1 is a simplified schematic diagram of an underactuated crane system embodying the present invention.

Fig. 2 is a block diagram of a high-performance anti-sway positioning control method implemented in the present invention.

Fig. 3 is a flowchart of a speed planning method according to an embodiment of the present invention.

Fig. 4 is a block diagram of the overall structure of the system implemented by the present invention.

Detailed ways

The method of the present invention will be described in detail below in conjunction with the accompanying drawings.

The trolley of the overhead crane is a complex underactuated system. The number of independent control variables of the system is less than the number of degrees of freedom of the system. It is a kind of nonlinear system. After simplified processing, it is shown in Figure 1: an overhead crane with mass M The trolley moves along the x-axis under the action of force F, and a heavy object with mass m is hung on the trolley of the bridge crane through a wire rope to perform a simple pendulum motion.

The displacement of the bridge crane trolley and the weight in the plane coordinate system:

Where L is the total energy of the system, and the bridge crane trolley is modeled by the Euler-Lagrange method, and the differential equation of motion of the system is obtained:

Where Q _x is the force exerted by the degree of freedom x on the bridge crane, ignoring the weight of the wire rope and air resistance, the stiffness of the wire rope is large enough, and its length change can be ignored. Since θ is generally less than 10 degrees, sinθ≈0, cosθ≈1, the system differential equation is simplified as follows:

It can be seen from the obtained mathematical model that the system input variable is only one Q _x , one output variable is the angle θ, and the other is the displacement x, so the system is a nonlinear second-order underactuated system.

According to the obtained differential equation, take the initial conditions: t=0, θ=0, make: Solving the differential equation, let θ(t)=ω(t), the state equation and system motion equation of the system can be obtained as follows:

According to formula (9), it can be seen that the model satisfies the elliptic curve equation. If the initial state satisfies θ(t)=θ(t ₀ ), ω(t)=ω(t ₀ ), substituting it into formula (9), we can get At any time θ(t), ω(t) satisfies the following relationship:

According to formula (10), the phase plane motion relation equation of the system is obtained by eliminating t as follows:

According to formula (11), three phase plane situations can be summarized: at any moment, when the initial state θ(t)=θ(t ₀ ), ω(t)=ω(t ₀ ) is a constant value, θ(t) , the relative trajectory of ω(t) is based on the point is a group of concentric ellipses with the center of the circle; when the trolley moves at a constant speed, a=0, the load performs an approximate pendulum motion with the center at the vertical position, and the motion track is a group of concentric ellipses with (0,0) as the center; when the initial State θ(t)=0, ω(t)=0, , the trajectory is a set of ellipses whose right endpoint is (0,0), and whose size is related to the acceleration a.

Therefore, by changing the acceleration a to construct the phase plane trajectory of the crane, when the process time of uniform acceleration or deceleration of the trolley satisfies an integer multiple of the pendulum-like period, the swing angle and angular velocity can return to 0, and the trolley can be eliminated after it stops. swing effect. When the load angle and angular velocity are both 0, if the trolley moves at a constant speed, there will be no swinging of the load during the uniform movement stage, and the effect of eliminating the swing when the trolley travels at a constant speed is achieved. In order to avoid large angles during acceleration and deceleration, when the car is in the initial state θ(t)=0, ω(t)=0, After the acceleration a starts to move at a certain constant, before the load reaches the maximum angle, make the angular velocity a of the trolley change from a certain constant to 0, that is, the trolley starts to move at a constant speed, and the trajectory of the load on the phase plane becomes the center at the origin. oval. At this time, the load angle continues to increase, and the angular velocity also continues to increase. When the load swings to the same angle, at the position of the angular velocity with the same magnitude and opposite direction, the trolley continues to move forward with the same acceleration a until the angle and angular velocity of the load return to 0, which can effectively reduce the swing angle of the load during acceleration and deceleration .

The anti-sway control method and system for industrial cranes based on adaptive speed planning actually establishes the kinematics model and anti-sway control model of the crane system based on the Lagrange equation. Adaptive speed planning uses a multi-stage acceleration and deceleration control algorithm to make the crane follow Run the planned speed curve to obtain a stable anti-sway effect. The specific implementation is divided into the following steps:

Step 1: Calculate the target distance (Δx=|x ₂ -x ₁ |) from the current position x ₁ and the target position x ₂ , and use the adaptive speed planning algorithm to obtain the maximum speed v _n of the crane and the number of acceleration and deceleration segments n ,;

Step 2: In the initial acceleration stage, accelerate from the initial velocity v ₀ (0m/s, static state) to the velocity v ₁ with the acceleration a (system setting), maintain a constant speed of t _s at the current velocity v ₁ , and then Velocity v ₁ accelerates to velocity v ₂ with acceleration a, and keeps moving at a constant speed for a period of time t _s at current velocity v _2. According to this law, accelerate n times to reach the target velocity v _n , and the velocities after each acceleration are v ₁ , v ₂ ... v _n , get the velocity curve and displacement in the acceleration stage;

Step 3: In the uniform motion stage, according to the uniform motion curve of the speed planning curve, the crane moves at a speed v _n for t _r seconds;

Step 4: Stop the deceleration stage, decelerate from the initial velocity v _n to the velocity v _n-1 with the acceleration -a, maintain a constant speed of t _s at the current velocity v _n-1 , and then start from the velocity v _n-1 with the acceleration - a decelerates to the speed v _n-2 , and maintains a constant speed t _s at the current speed v _n-2 . According to this rule, the speed after deceleration n times is 0m/s, and the speed after each deceleration is v _{n- 1} ... v ₂ , v ₁ , 0, get the velocity curve and displacement in the deceleration stage.

An adaptive speed planning industrial crane control method and system described in this patent, the device mainly includes: PLC controller (1), angle measuring instrument (2), laser distance measuring instrument (3), frequency converter (4 ), an AC asynchronous motor (5), a crane (6) moving along the direction of the beam, and a host computer (7), the PLC controller (1) and the host computer (6) are independently developed by SCIYON The module in the DCS system, the angle measuring instrument (2) adopts the product of SATEC Company (SATEC), and the laser range finder (3) adopts the product of SICK Company.

Through SCIYON's NT6000DCS system PC (7) configuration software to realize the industrial crane anti-sway control system algorithm based on adaptive speed planning, its output is connected to the input of the PLC controller (1) for downloading and writing the program into the PLC controller (1), the output of the PLC controller (1) is connected to the input of the frequency converter (4) to realize the control of the frequency converter (4) by the PLC controller (1), and the AC frequency converter (4) controls the The speed of the asynchronous motor (5) is driven by the AC asynchronous motor (5) and the crane (5) that can move along the direction of the beam moves according to the planned speed curve. The company's DL-100 laser range finder (3) transmits the real-time angle and real-time position of the crane to the upper computer (6) detection software and real-time database system of the DCS system to monitor the speed curve and real-time angle curve of the crane.

Claims (4)

1. an industrial crane control method of adaptive speed planning, it is characterized in that the method is based on the Lagrange equation to set up the kinematics model and the anti-sway control model of the crane system, and the adaptive speed planning uses multi-stage acceleration and deceleration to realize the stable anti-sway effect, Adaptive control of the number of speed segments and the maximum speed, setting the maximum operating speed of the crane is divided into k levels, the k level is the highest speed, and the first level is the lowest speed. The adaptive speed planning is specifically divided into the following steps: Step 1: Calculate the target distance (Δx=|x ₂ -x ₁ |) from the current position x ₁ and the target position x ₂ , and set the maximum speed v _n of the crane equal to the kth gear speed of the crane, according to the formula Calculate the number n of acceleration and deceleration segments, where a is the set acceleration of the crane, and T is the simple pendulum period of the crane; Step 2: Determine whether the current number of acceleration and deceleration steps n is greater than or equal to 2, if n is greater than or equal to 2, continue to step 3, if n is less than 2, then reduce the final speed v _n of the crane by one gear, go to step 1, and recalculate n; Step 3: In the initial acceleration phase, plan the velocity curve and acceleration displacement in the acceleration phase, from the initial velocity v ₀ =0m/s, accelerate to the velocity v ₁ with the acceleration a set by the system, and maintain the current velocity v ₁ for a period of time t _s moving at a constant speed from speed v ₁ to speed v ₂ with acceleration a, and maintain a constant speed at current speed v ₂ for a period of time t _s . According to this rule, accelerate n times to reach the target speed v _n , after each acceleration The velocities are v ₁ , v ₂ ... v _n respectively, and the velocity curve and displacement in the acceleration stage are obtained; Step 4: Stop the deceleration phase, plan the speed curve and deceleration displacement in the deceleration phase, decelerate from the initial speed v _n in the deceleration phase to the speed v _n-1 with acceleration-a, and maintain the current speed v _n-1 for a period of time t _s Move at a uniform speed, then decelerate from speed v _n-1 to speed v _n-2 with acceleration-a, and keep moving at a constant speed for a period of time t _s at the current speed v _n-2 . According to this rule, after decelerating n times, the speed is 0m/ s, the speed after each deceleration is v _n-1 ... v ₂ , v ₁ , 0, and the speed curve and displacement in the deceleration stage are obtained; Step 5: Calculate the time t _r used in the constant velocity stage from the target distance, the displacement in the acceleration stage, the displacement in the deceleration stage and the velocity v _n , if t _r is greater than zero, then get the velocity curve and displacement in the constant velocity stage and go to step 6, if t _r If it is less than zero, subtract 1 from the number of acceleration and deceleration stages n, and then go to step 2; Step 6: Output the adaptive speed planning curve of the crane. 2. A kind of industrial crane control method of adaptive speed planning according to claim 1, it is characterized in that in step 3, v ₁ , v ₂ ... v _n these n speed values and the setting of t _s time value As follows: l is the length of the rope, g is the acceleration due to gravity, and the period of the simple pendulum 3. a kind of industrial crane control system of the adaptive speed planning of method as claimed in claim 1, it is characterized in that this control system mainly comprises: PLC controller (1), angle measuring instrument (2), laser range finder ( 3), inverter (4), AC asynchronous motor (5), crane (6) moving along the direction of the beam, and host computer (7); through the configuration software of the host computer (7) in the DCS system, the adaptive speed based on In the planned anti-sway control system for industrial cranes, the output terminal of the upper computer (7) is connected to the input terminal of the PLC controller (1), and is used to download the program into the PLC controller (1), and the PLC controller (1) The output terminal of the inverter (4) is connected to the input terminal of the frequency converter (4) to realize the control of the frequency converter (4) by the PLC controller (1). The frequency converter (4) controls the speed of the AC asynchronous motor (5), and the AC asynchronous motor (5) Drive the crane that can move along the direction of the beam (6) to move according to the planned speed curve, and at the same time, the real-time angle and real-time position of the crane can be transmitted to the DCS system through the angle measuring instrument (2) and the laser rangefinder (3) The built-in upper computer (7) detection software and real-time database system monitor the speed curve and real-time angle curve of the crane. 4. the industrial crane control system of the self-adaptive speed planning of method as claimed in claim 3, it is characterized in that described PLC controller (1) and host computer (7) adopt the module in the DCS system independently developed by Keyuan Company , the angle measuring instrument (2) adopts the product of Saiteke Company, and the laser range finder (3) adopts the product of SICK Company.