CN107381352B - A kind of acceleration time adjustable crane is anti-to shake control method - Google Patents

Abstract

The invention discloses a crane anti-sway control method with adjustable acceleration time, which includes establishing a mathematical model of the swing angle of the hoist, designing the acceleration signal of the crane, the acceleration signal includes unknown coefficients, designing the maximum speed and acceleration time of the crane, Solve the unknown coefficient of the acceleration signal of the crane, so that at the end of the acceleration time of the designed acceleration signal, the amplitude of the hoisting residual swing input to the shaping controller is zero, and the final acceleration signal of the crane is input to the shaping controller. According to different working conditions, the present invention can select the appropriate acceleration time and maximum operating speed, and design the shaping controller in combination with the pendulum length of the hoisting weight to control the crane, realize zero swing of the hoisting weight when the acceleration is completed, and further improve the working efficiency of the crane.

Description

A crane anti-sway control method with adjustable acceleration time

technical field

The invention relates to a crane anti-sway control method with adjustable acceleration time, belonging to the technical field of crane control.

Background technique

As an important material handling equipment, cranes are often used to perform important and challenging operational tasks, such as building bridges, dams and high-rise towers. Typically, cranes are able to transfer heavy loads quickly, smoothly and precisely. However, during the start-up and braking process of the crane, the hoisting weight will swing significantly, and these swings may cause great danger to the production process, resulting in delays in the production process or increased maintenance costs.

The main objectives of crane control research are to reduce or eliminate residual sway at the end of the handling process, reduce settling time and enhance safe operating conditions. Researchers have tried various control techniques to achieve these goals. Among them, feedback control is widely adopted due to its robustness to system uncertainties. However, one of the main disadvantages of feedback control is the need to change the physical structure of the system and add additional sensors or actuators. Another control method is open-loop control, which is representative of input shaping technology. This method requires little change to the existing system, so it is widely used in vibration suppression of flexible systems such as cranes.

The input shaping method is to convolute a series of pulses within a certain period of time with the reference command normally used, and reduce the residual swing by accelerating multiple times. In the traditional input shaping method, the period of the pulse sequence is fixed and must match the modal parameters of the system, which is heavily dependent on the period of the system. The reference command is usually constant, and the shaping command obtained by convolution calculation is a series of step functions. Frequent step acceleration will cause the vibration of the actuator. All disadvantages. With the development of electronic speed control circuits, smooth characteristics such as S-curve, trigonometric function, Gaussian function and cam polynomial are used for input shaping. These characteristics introduce a low-pass filtering effect that greatly reduces residual vibration, but at the same time cause a large loss of rise time.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of the prior art, provide a crane anti-sway control method with adjustable acceleration time, allow free choice of the duration of the acceleration phase and the maximum design speed, and design shaping control in combination with the pendulum length of the hoisting weight The crane realizes zero swing of the hoisting load at the end of the transfer process, further improving the working efficiency of the crane.

In order to solve the above technical problems, the present invention provides a crane anti-sway control method with adjustable acceleration time, which includes the following steps:

1) Establish the mathematical model of the swing angle of the hoist;

2) Design the acceleration signal of the crane;

3) According to the maximum speed and acceleration time of the crane, the unknown coefficient of the acceleration signal of the crane is solved;

4) Input the final acceleration signal of the crane to the shaping controller.

The aforementioned step 1), the mathematical model of the swing angle of the hoist is:

Among them, θ is the swing angle of hoisting weight, u is the displacement of crane trolley, is the acceleration of the crane trolley, l is the length of the hoisting wire rope, g is the acceleration of gravity,

When the length of the hoisting wire rope is constant, the mathematical model of the hoisting swing angle is simplified as:

in, Oscillate natural frequency for lifting weights.

The aforementioned step 2), the acceleration signal of the design crane is:

Among them, τ is the acceleration time, t is the time variable, and A and B are unknown coefficients.

The solution process of aforementioned coefficient A is: to the acceleration signal of the crane of described step 2) design Integrate during the acceleration time to obtain the maximum value of the crane speed: v _max = Aτ,

According to the maximum speed and acceleration time of the crane, the constant A is determined as:

The solution process of the aforementioned coefficient B is:

5-1) Under zero initial conditions, the acceleration signal of the crane designed in step 2) Substituting into the simplified mathematical model of the swing angle of the hoisting weight:

Among them, θ(t) is the swing angle of hoisting weight changing with time t.

5-2) Take t=τ, and obtain the hoisting weight swing angle _θ τ at time τ:

5-3) Deriving the swing angle θ(t) of the hoisting weight, taking t=τ, and obtaining the angular velocity of the hoisting weight at time τ

5-4) At the end of the acceleration time τ, the amplitude AMP of the residual swing of the hoisting weight is:

AMP=0 is required, then

Will and Substituting into the amplitude AMP of the residual swing of the hoisting weight, we get:

because but:

The aforementioned final crane acceleration signal is:

The beneficial effect that the present invention reaches:

In the crane control system, the present invention can select the appropriate acceleration time and maximum running speed according to different working conditions, and design the shaping controller in combination with the pendulum length of the hoist to control the crane, realize zero swing of the hoist when the acceleration is completed, and further improve improve the working efficiency of the crane.

Description of drawings

Fig. 1 is the schematic diagram of crane hoisting;

Figure 2 is a schematic diagram of crane control;

Fig. 3 is a schematic diagram of the input shaping controller;

Figure 4 is the response of the hoisting weight swing angle when τ = 1s in the simulation.

Detailed ways

The present invention will be further described below. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

As shown in Figure 1, the schematic diagram of crane hoisting, the trolley with mass M runs horizontally along the track, u is the displacement of the trolley, is the acceleration of the trolley, l is the length of the hoisting wire rope, m is the mass of the hoisting weight, and θ is the swing angle of the hoisting weight.

Then the mathematical model of the swing angle of the hoist is:

where g is the acceleration due to gravity.

Lifting weight swing natural frequency:

When the rope length of the hoist is constant, the mathematical model of the swing angle of the hoist can be simplified as:

The control principle of the crane is shown in Figure 2, the acceleration signal of the crane Input the shaping controller to form a control signal V that meets the requirements, which is amplified by the drive circuit and then drives the actuator to move to realize cargo transfer. Due to the existence of inertia, the hoisting weight will produce a swing angle θ.

In order to realize the crane anti-sway control method with adjustable acceleration time, the introduction As the acceleration signal of the crane, the acceleration time is τ, and t is the time variable. For Integrating during the acceleration time, the maximum value v _max =Aτ of the crane speed can be obtained. The constant can be determined according to the designed maximum speed and acceleration time

Under zero initial conditions, the Substituting into the simplified mathematical model of the swing angle of the hoisting weight, we can get:

θ(t) is the swing angle of the hoist that changes with time t.

in:

Taking t=τ, we can get the swing angle of hoisting weight at time τ The angular velocity of the hoist can be obtained by deriving the swing angle of the hoist

At the end of the acceleration time τ, the performance of the input shaper is measured by the amplitude of the residual swing of the hoisting weight. Since there is no acceleration on the boom of the crane at this time, the system swings freely without damping. Amplitude of hoisting residual swing

Obviously, if the residual swing of the hoisting weight is set to 0, then the

Therefore it can be and Substitute into the amplitude AMP of the residual swing of the hoisting weight,

get:

because Known, the calculated coefficients are:

As shown in Figure 3, the acceleration signal of the crane is calculated according to the maximum speed and acceleration time of the crane input by the operator, and is input to the shaping controller. The shaping controller performs convolution operations on the initial command and the shaping filter to obtain the shaped The acceleration signal and the control signal pass through the drive amplifier unit and then control the actuator, so that the residual swing angle of the hoisting weight after the boom is accelerated is 0.

In the present invention, when the selected acceleration time τ is equal to the natural period τ _n =2π/ω _n of the system, and the value of B is 0, the trolley runs at a constant acceleration.

In the simulation, the length of the hoisting rope l=0.6m and the maximum operating speed of the crane v _max =0.3m/s, when the acceleration time τ= _τn =1s is selected, the simulation results are shown in Figure 4. It can be seen from the figure that after the acceleration process ends, the swing angle of the hoist is 0, which realizes a swing-free transfer process. The simulation results show that the proposed control method can realize the adjustable acceleration time and can eliminate the residual swing during operation.

The above is only a preferred embodiment of the present invention, and it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and modifications can also be made. It should also be regarded as the protection scope of the present invention.

Claims (3)

1. The crane anti-swing control method with adjustable acceleration time is characterized by comprising the following steps of:

1) establishing a mathematical model of a hoisting swing angle;

2) designing an acceleration signal of the crane as follows:

wherein,is an acceleration signal, tau is acceleration time, t is a time variable, A, B is an unknown coefficient;

3) solving unknown coefficients of the crane acceleration signals according to the maximum speed and the acceleration time of the crane;

the solution process of the unknown coefficient A is that the acceleration signal ü of the crane designed in the step 2) is integrated in the acceleration time to obtain the maximum value of the crane speed v_max＝Aτ，

According to the maximum speed and the acceleration time of the crane, determining a constant A as follows:

the solving process of the unknown coefficient B is as follows:

3-1) under the zero initial condition, substituting the acceleration signal ü of the crane designed in the step 2) into a simplified mathematical model of the hoisting swing angle to obtain:

wherein θ (t) is a swing angle of the hoist varying with time t, ω_nIn order to swing the natural frequency of the hoist,

g is the acceleration of gravity;

3-2) obtaining the hoisting swing angle theta at the moment tau by taking t as tau_τ：

3-3) deriving the hoisting swing angle theta (t), and obtaining the hoisting angular speed at the moment tau by taking t as tau

3-4) at the end of the acceleration time τ, the amplitude AMP of the sling residual oscillation is:

when AMP is required to be 0, then

Will be provided withAndsubstituting into the amplitude AMP of the sling residual oscillation, yields:

because of the fact thatThen:

4) and inputting the final crane acceleration signal to a shaping controller.

2. The crane anti-swing control method with adjustable acceleration time according to claim 1, wherein in the step 1), the mathematical model of the swing angle of the hoist is as follows:

wherein theta is a swing angle of the hoist, ü is a displacement of the crane trolley, ü is an acceleration of the crane trolley, l is a length of a hoist steel wire rope, g is a gravitational acceleration,

when the length of the hoisting steel wire rope is not changed, the mathematical model of the hoisting swing angle is simplified as follows:

wherein,the natural frequency of the swinging of the hoisting weight.

3. The method for controlling crane anti-swing with adjustable acceleration time according to claim 1, wherein the final crane acceleration signal is: