Jib crane control method and control system

Abstract

To provide a control method and a control system capable of absorbing residual vibration when the rope length is varied in response to the elevation of a jib.SOLUTION: Input in a non-controlled state of a linear model, by which only an elevation angle is varied with respect to a jib while the rope length between a tip of the jib and a suspended load is made constant, is set in advance as basic input. Vibration output absorbing residual vibration of the suspended load when change in elevation is terminated, is set as reference vibration output and reference control input is derived to obtain the reference vibration output by applying the input shaping method using a zero-vibration input shaper with respect to the basic input. A control model prescribed by the reference control input and the reference vibration output is formed as a normative control model. When a dynamic model at the time when the elevation angle of the jib is varied while changing the rope length is compared with a dynamic model in the normative control model, control input at the time when it is assumed that the vibration output of the former dynamic model and the vibration output of the latter dynamic model are identical to each other is derived as final control input. The jib is operated based on the input.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a control method and device for absorbing residual vibrations that occur when a suspended load moves nonlinearly when a jib crane is operated to simultaneously raise and lower a jib and hoist and lower a suspended load. [Background technology]

[0002] Jib cranes (also called rotary cranes) are widely used in ports and ships, etc., and are used to load and unload heavy cargo. These cranes are operated by three elements: rotation, elevation, and lifting. The rotation rotates the entire crane, and the elevation tilts the jib (also called the boom). The lifting and lowering is performed by winding up the wire that suspends the load. Because the rope used for hoisting the load is flexible, each of the above operations causes the load to sway, and residual vibration (load sway) occurs even when the above operations are stopped. When this type of residual vibration occurs, the load is not suspended directly below the tip of the jib, making it difficult to grasp the position of the load, and it is necessary to wait for the residual vibration to subside before moving on to the next operation. As a result, the unloading time is significantly extended and the stability of the system is reduced.

[0003] In order to eliminate the residual vibration, when the jib is operated manually, the operator operates the jib slowly to suppress the generation of vibration to the suspended load. On the other hand, when entrusting it to a vibration control system, as is well known, two types of control methods are assumed: feedback control and feedforward control.

[0004] As is well known, feedback control is excellent at dealing with uncertain disturbances by obtaining the sway angle of the load in real time and providing appropriate control input. However, building the system requires an advanced sensor structure, which is expensive and requires maintenance.

[0005] Therefore, feedforward control is considered desirable for ease of implementation and simplification of the measurement system. In this case, a control method using the input shaping method is generally used. This input shaping method intelligently changes the original command by convolving a sequence of impulses called an input shaper, and the input shaper is designed so that vibrations caused by all impulses are self-cancelled (see Non-Patent Documents 1 and 2).

[0006] Regarding the input shaping method, it has been proposed to implement a non-robust zero vibration (ZV) input shaper and a shaper including a robust zero vibration derivative (ZVD) and specified insensitivity (SI) in a jib crane that only performs elevation and elevation movements (Non-Patent Documents 3 and 4). An input shaper designed to be able to control vibration in a non-initial state has also been proposed (see Non-Patent Document 5). [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] NCSinger, and WPSeering, “Preshaping Command Inputs to Reduce System Vibrations”, ASME J. of Dynamic Systems, Measurement and Control, Vol. 112, 1990, pp.76-82 [Non-Patent Document 2] W. Singhose, “Command shaping for flexible systems: A review of the first 50 years.” Int. J. Precis. Eng. Manuf., Vol. 10, 2009, pp.153-168 [Non-Patent Document 3] J.Danielson, “Mobile boom cranes and advanced input shaping control”, Master's thesis, School of Mechanical Engineering, Georgia Institute of Technology, Georgia, USA, 2008 [Non-Patent Document 4] E.Maleki and W.Singhose, “Dynamics and zero vibration input shaping control of small-scale boom crane,” in Proc. of the 2010 America Control Conf., Jun. 2010, pp.2296-2301 [Non-Patent Document 5] D. Newman and J. Vaughan, “Command shaping of a boom crane subject to nonzero initial conditions,” in 2017 IEEE Conf. on Control Technology and Applications (CCTA), Aug. 2017, pp.1189-1194 Summary of the Invention [Problem to be solved by the invention]

[0008] The technology disclosed in the above-mentioned non-patent literature reduces residual vibration, but does not control residual vibration to nearly zero. In addition, there is a problem that the input shaping control designed for a two-dimensional time-invariant linear plant cannot be applied to a time-varying nonlinear system. In other words, the control of residual vibration when the rope length changes in addition to the elevation and elevation of the jib becomes nonlinear, but a control method for such a nonlinear system has not yet been verified.

[0009] The present invention has been made in consideration of the above points, and its object is to provide a control method and a control system that can absorb residual vibrations when the rope length changes in addition to the elevation of the jib. [Means for solving the problem]

[0010] Therefore, the present invention, which relates to a control method for a jib crane, is a control method for reducing residual vibrations that occur in a suspended load when a jib is raised or lowered in a jib crane and the suspended load is moved to a predetermined position by winding up the rope, and is characterized in that an input of a non-controlled state in a linear model in which only the elevation or lower angle of the jib is changed while keeping the rope length from the tip of the jib to the suspended load constant is predetermined as a basic input, an input shaping method using a zero vibration input shaper is applied to the basic input, and a vibration output that absorbs the residual vibration of the suspended load at the end of the change in elevation or lower is set as a reference vibration output, a reference control input for obtaining this reference vibration output is derived, a control model defined by the obtained reference control input and reference vibration output is formed as a normative control model, a dynamics model when the elevation or lower angle of the jib is changed while changing the rope length is compared with a dynamics model in the normative control model, and a control input when it is considered that the vibration outputs of the two are the same is derived as a final control input, and the jib is operated based on the final control input.

[0011] According to the above configuration, in a linear model in which the rope length is not changed, a control input and a vibration output capable of absorbing the residual vibration are derived, and the control input in a nonlinear system when the rope length is changed is converted to a control input, thereby obtaining an expected vibration output. That is, the vibration output output by the basic input is the vibration behavior in the linear model, which is the vibration behavior when the suspended load is moved to the target position without considering the control (residual vibration). Therefore, by deriving a reference control input that controls to cancel this residual vibration, a normative model that enables the absorption of the residual vibration in the linear model can be constructed. Therefore, by forming these reference control inputs and reference vibration outputs as a normative model and applying a dynamics model in which the rope length is changed to the normative model, the residual vibration in the nonlinear model can be absorbed as in the linear model.

[0012] In the invention having the above configuration, the rope length when the reference vibration output is generated can be an intermediate length within a range of the planned length of the rope length change, whereby the reference vibration output can be obtained at the intermediate point of the entire planned rope length change, and can be regarded as corresponding to the vibration from the start point to the end point of the rope length change.

[0013] In addition, in the inventions of each of the above configurations, the basic input is divided into the time of operation of the jib continuing from the starting state when the jib elevation angle changes, into the time from the starting state to any intermediate state, the time from that intermediate state to reaching the target angle, and the time after reaching the target angle, and is defined by the magnitude of the impulse input for each time, and the magnitude of the impulse at each time can be limited within the range of conditions that can absorb the residual vibration of the suspended load using the input shaping method using a zero vibration input shaper.

[0014] According to the above configuration, when the magnitude of the impulse for each divided time period as described above satisfies a predetermined condition, it is possible to absorb the residual vibration based on the final control input. This means that the reference control input and the reference vibration output obtained on the premise of a basic input that does not satisfy the predetermined condition are not used as a reference model. If such a reference model is used, it will not be possible to absorb the residual vibration.

[0015] The present invention relating to a control system for a jib crane is a control system controlled by a control method having any of the above-mentioned configurations, the control system including a tilt drive unit for tilting the jib, a winding drive unit for winding up a rope for suspending a load from the tip of the jib, and an input unit for specifying a destination of the load, the control system including an output unit for outputting control signals to the tilt drive unit and the winding drive unit, a control unit for receiving a signal from the input unit and controlling the amount of change in the tilt drive unit and the winding drive unit, and an output unit for outputting a control signal from the control unit to the tilt drive unit and the winding drive unit, the control unit further including a calculation unit and a memory unit, the calculation unit calculates the position of the load based on the state of the tilt drive unit and the winding drive unit, and from the input information on the destination of the load, The non-controlled input in a linear model in which only the elevation / depression angle relative to the jib is changed while keeping the rope length from the tip of the jib constant is calculated as a basic input, and an input shaping method using a zero vibration input shaper is applied to the basic input to derive a reference control input for obtaining a reference vibration output that absorbs the residual vibration of the load when the elevation / depression change ends.A control model defined by the reference control input and the reference vibration output is formed as a normative control model, and a dynamics model when the elevation / depression angle of the jib is changed while changing the rope length is compared with a dynamics model in the normative control model, and a control input when the vibration outputs of the two are considered to be identical is derived as a final control input, and the memory unit stores the calculation results by the calculation unit.

[0016] According to the control device configured as above, the calculation unit calculates the basic input and further derives the reference control input, thereby making it possible to obtain, in the linear model, the reference control input for absorbing the residual vibration of the load when the change in elevation or elevation ends and the reference vibration output at that time. These reference control inputs and reference vibration outputs enable the absorption of residual vibration in the linear model, but by forming them as a reference model, it becomes possible to apply a dynamic model in which the rope length changes to the reference model and enable the absorption of residual vibration in the nonlinear model. Effect of the Invention

[0017] According to the present invention, which relates to a method for controlling a jib crane, it is possible to absorb residual vibrations in a nonlinear system in which the rope length changes in addition to the elevation of the jib while using the existing input shaping method used to eliminate residual vibrations in a linear model. This control method is a feedforward control, so it is possible to suppress vibrations in a short time compared to feedback control, and it is possible to provide a control method at low cost and to realize a control method that is easy to implement.

[0018] Furthermore, according to the present invention relating to a jib crane control system, it is possible to implement it on an actual jib crane and to appropriately control the movement of a suspended load under various different conditions. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an explanatory diagram showing an outline of the configuration of a jib crane. [Diagram 2] FIG. 1 is a reference diagram for a linear model. [Diagram 3] FIG. 1 is a reference diagram for a nonlinear model. [Figure 4] FIG. 4 is a block diagram of a control system illustrating a control method. [Diagram 5] 1 is a flowchart of a control method. [Figure 6] FIG. 2 is a block diagram showing an overview of the control system. [Figure 7] 1 is a graph showing the results of Experimental Example 1. [Figure 8] 1 is a graph showing the results of Experimental Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, an outline of the jib crane to be controlled will be described. FIG. 1 is a schematic diagram of a general jib crane. As shown in this figure, a general jib crane 1 has a jib 4 extending from a main body 3 installed on the top of a crane post 2, and the jib 4 is raised and lowered and a hanging rope 6 is wound up by operation of a drive device (actuator such as a winch) 5 mounted on the main body 3. The main body 3 is also rotatable on a horizontal plane, and the jib crane 1 as a whole moves a suspended load 7 three-dimensionally by rotating, raising and lowering, and winding up and down.

[0021] The jib crane 1 in Fig. 1 is simplified, so only a single actuator (winch, etc.) 5 is shown, and a configuration is shown in which the elevation angle of the jib 4 is changed by a straight wire rope 41, but in an actual crane, the wire rope 41 is stretched in a wavy pattern together with a load-reducing means such as a movable pulley, and an actuator (winch, etc.) 5 is installed for not only elevating or lowering the jib 4, but also for winding up the suspension rope 6. Also, although each rope 6, 41 is shown as a single rope, there are also cases in which the load is distributed by multiple ropes. Here, in order to simplify the device configuration, it is shown as a straight line and as a single rope.

[0022] <Embodiments Related to Control Method> Next, an embodiment of the invention relating to a control method for a jib crane will be described. Figures 2 and 3 are models of a general structure of a jib crane. Here, a winding device for the suspension rope 6 is omitted. Also, Figure 2 is a diagram for explaining a model (linear model) in which the length of the suspension rope 6 (hereinafter sometimes abbreviated as rope length) is not changed, and Figure 3 is a diagram for explaining a model (nonlinear model) in which the rope length is changed. Therefore, please refer to Figure 2 for an explanation of the linear model, and refer to Figure 3 for an explanation of the nonlinear model.

[0023] Linear Models (See Figure 2) In the control method of this embodiment, the control input is calculated in advance by a linear model, and then applied to a nonlinear model. Therefore, first, the vibration behavior in the linear model is derived. The linear model is a state in which only elevation and depression are operated with the rope length l of the hoisting rope 6 kept constant. Therefore, when the jib 4 is operated to a target elevation and depression angle, that is, when the load 7 is moved to a target position only by elevation and depression, an actuator 5 such as a winch for changing the elevation and depression angle with respect to the jib 4 is operated. The transfer function in this case can be expressed by the following general formula.

[0024]

number

[0025] Here, the input (basic input) when changing the jib 4 to the target elevation angle is u r (t), then the basic input U r (t) can be expressed as follows:

[0026]

number

[0027] When the fundamental input as described above is applied, the load 7 will vibrate in accordance with the change in the jib 4. Therefore, the expected vibration output (fundamental vibration output) will be generated. Since the vibration output at this time changes only the elevation and elevation state of the jib 4 without considering the suppression of residual vibration, naturally, residual vibration will remain at the end.

[0028] Deriving reference control inputs and forming a normative model Therefore, by controlling the load to cancel out the vibrations during movement, the vibrations can be absorbed and the residual vibrations at the end can be suppressed. In this case, in order to suppress the residual vibrations by controlling the operation of the jib 4, it is necessary to output a signal to limit the angle (angle with respect to the vertical) of the suspension ropes 6 when the rope length of the suspension ropes 6 is constant, and the control input to obtain this output can be expressed by the following formula.

[0029]

number

[0030] The state of the rope angle due to such a reference input is formed as a reference model. The control input (reference control input) to enable the above-mentioned control can be derived by the input shaping method, which convolves a zero-input shaper with the basic input, as shown in the following equation.

[0031]

number

[0032] As shown in the above formula (3), the reference control input is derived by convolving the zero-input shaper with the fundamental input. The condition of the fundamental input is the above formula (2), and the fundamental vibration is suppressed by the reference control input. The vibration state (target vibration state) at this time is expressed by the following formula.

[0033]

number

[0034] Nonlinear Models (See Figure 3) The present invention relates to a control method related to a nonlinear model when raising and lowering the jib 4 and changing the hanging rope 6 are caused simultaneously. Next, vibration behavior in the nonlinear model will be described. First, the dynamics model (equation of motion) related to the control input (final control input u(t)) when vibration (θ) is caused when the angle φ of the jib 4 and the rope length l change is as shown in the following formula. However, the rotation of the jib 4 is not taken into consideration.

[0035]

number

[0036] Here, since the angle of the jib 4 and the rope length change from time 0 to a finite end time (τ), if they are to be realized in a finite end time (τ), the following conditions must be satisfied.

[0037]

number

[0038] Under the above conditions, it is assumed that the vibration output (vibration behavior (change in θ)) in the nonlinear model is the same as the vibration output (vibration behavior (change in ξ)) in the linear model. In this case, it can be shown as follows.

[0039]

number

[0040] Then, the above-mentioned reference model (the above formula (3)) becomes as shown in the following formula (10), and the nonlinear dynamics model (equation of motion (7)) becomes as shown in the following formula (11).

[0041]

number

[0042] Then, by rearranging the above equations (10) and (11) using the definition in (9) above, we obtain the following equation (12), and by further determining the control input (u(t)), we can obtain the following equation (13).

[0043]

number

[0044] Therefore, by introducing the above control input (u(t)) into the nonlinear model, the vibration behavior (change in θ) is controlled as shown in the following formula (14). The elevation and depression angle of the jib 4 at this time is also in the state shown in the following formula (15).

[0045]

number

[0046] Incidentally, since the above equation (13) includes a reference control input that forms a reference model, the above equation (13) can be written as the following equation (16) using the above equations (4) and (7).

[0047]

number

[0048] From the above equation (13), that is, the above equation (16), in order to obtain the control input (u(t)), it is necessary to solve the above equation (16), which is a differential and integral equation with respect to φ. However, since this is analytically difficult, a numerical solution is used. In order to obtain the above control input (u(t)), the basic input (u rThe design parameters (a, t1) included in the equation (t) (see equation (2) above) must be determined. Naturally, it is not possible to actually input basic inputs to operate the crane, so the solution to the nonlinear differential and integral equation shown in equation (16) above is sought. In this case, the minimum values ​​of the design parameters (a, t1) are found using the method shown in the following equation.

[0049]

number

[0050] The weighting coefficient in the above formula (17) is ω1=10 3 , ω2=10 5 Moreover, the above formula (17) can be calculated by using the command fmincon of MATLAB (registered trademark).

[0051] As described above, the reference model is formed by the state of the rope angle due to the reference control input in the linear model, as shown in equation (3) above, and by making it possible to obtain the same vibration behavior (vibration output) between the linear model and the nonlinear model, it is possible to obtain the control input (final control input) in the nonlinear model (i.e., when the elevation angle of the jib 4 and the rope length l change simultaneously).

[0052] The reference control input in this case is the input shaping method that uses a zero vibration input shaper to the basic input. However, this basic input is not actually input, but is a virtual input that includes unknown design parameters. For a given target value, a value that absorbs residual vibrations by a minimum value is assumed, and based on that assumption, it is further expanded into a nonlinear model.

[0053] Therefore, the movement (transportation) of the load 7 can be controlled by setting the initial position to the target position and suppressing residual vibrations according to the conditions required for the movement. The initial position and target position of the load at this time can be determined by the elevation / depression angle of the jib 4 and the rope length (the distance from the tip of the jib to the load), respectively. In other words, the elevation / depression angle of the jib 4 and the rope length can be grasped by the winding state of the actuator 5 such as a winch, and can be performed by detecting the number of winds and the winding angle of the actuator 5 such as the winch.

[0054] <Actuator control> As described above, when the control input (final control input) can be obtained, in order to actually operate the crane, an actuator 5 such as a winch is operated to raise or lower the jib 4 and reel in the hoisting rope 6.

[0055] Here, we will explain the dynamics when changing the elevation / depression angle of the jib 4 by the actuator (winch, etc.) 5 as shown in Fig. 3. This dynamics relates to the change (raising and lowering) of the elevation / depression angle of the jib 4 by the actuator 5, and the rope 6 is assumed to be wound at a substantially constant speed by an actuator (winch, etc.) not shown.

[0056] When focusing on the triangle FTJ in Fig. 3, the length D of FT can be expressed as in the following formula (18). The angle of the winding drum A changed by the actuator 5 is given by the following formula (19), the angular velocity at that time is given by the following formula (20), and the angular acceleration is given by the following formula (21). In each formula, α1 is the angle between FJ and the horizontal, b1 is the radius of the winding drum, and d1 is the length of FJ.

[0057]

number

[0058] In this way, the elevation and depression angles of the jib 4 can be controlled by controlling the angle of the winding drum of the actuator 5. However, in actual control, the angular velocity and angular acceleration have upper limits due to the output of the actuator actually mounted on the jib crane. As an example, the upper limit of the angular velocity is 5.47 (rad / s), and the upper limit of the angular acceleration is 1.25 (rad / s). 2 The same applies when winding up the suspension rope 6. For example, the upper limit of the winding speed of the rope length is 1.5 (m / s), and the acceleration is 0.6 (m / s 2 In either case, the final control input is calculated within the range that can be changed by the speed and acceleration below the upper limit mentioned above.

[0059] <Control method (control design method)> As described above, according to the control method of this embodiment, the control system shown in the block diagram of FIG. r The reference control input (u bar) is derived by convolution of the input shaper (IS) with the reference control input (t) and a reference model is formed together with the vibration behavior (reference vibration output (ξ)) output based on the reference control input. The reference model at this time is a linear model. These inputs and outputs are incorporated into the control method. At this time, the rope length (l bar) at the initial input in the linear model and the rate of change in nonlinearity (when the rope length changes) are also incorporated into the control method, and as described above, a control signal (final control input (u)) is derived on the premise that the vibration behavior is the same as the vibration behavior (reference vibration output (ξ)) by the linear model, and the control signal is output to the jib crane via a servo driver, etc., to suppress the vibration behavior (θ) to zero. The vibration control at this time is feedforward control, and suppressing the vibration behavior (θ) to zero means that the vibration is converged (residual vibration is made zero) when the load has finished moving to the target position, and it is a control method that absorbs vibration including residual vibration during the movement process.

[0060] <Summary> The above-described embodiment can be summarized in a flowchart as shown in FIG. 5. The control method will be described with reference to this flowchart. When control is started, the position of the load is confirmed from the state of the actuator (S101). The position information of the load may be obtained by sequentially reading out information stored in a storage means, or the angle of the drum constituting the actuator may be detected to determine the position of the load. Next, when a target position to which the load should be moved is input (input by an operator) (S102), a reference control input related to the movement to the target position is derived (S103). As described above, the basic input is used for the reference control input. In addition, since the reference vibration output is derived at the same time as the derivation of the reference control input, a reference model is formed from both of them (S104). When the reference model is formed, the design parameters are calculated with reference to this (regarding them as the same vibration output) (S105). The design parameters are (a, t1) that form the above-described basic input, but are determined at this stage in order to minimize the evaluation function (the above-described formula (17)) (S106). Since the final control input is determined by determining the design parameters (a, t1), the control input is calculated (S107) and a control signal is output to the actuator as feedforward control (S108). In this manner, the movement of the load is terminated by executing the feedforward control.

[0061] <Control device> Since the control method of this embodiment is configured as described above, the control system using this method uses a control device 8 as shown in FIG. 6. The control device 8 can be configured with a general PC, but at least requires an input / output unit for inputting and outputting predetermined information, a calculation unit, and a storage unit. The input / output unit is for inputting angle information of the actuator's winding drum and outputting a control signal to the actuator. The angle information of the actuator's winding drum is for detecting the position of the load from the elevation / depression angle and the rope length, and specifically, a detection value detected by an encoder or the like is input. The output control signal is output to a servo motor (actuator) via a servo driver 82. The servo motor outputs the magnitude and timing of the drive. Note that the control method of this embodiment is not feedback control but feedforward control, so the encoder information is used only for calculating the position of the load. In addition, each input / output is provided separately for the elevation / depression angle and the rope length.

[0062] The above input signals are each subjected to a predetermined calculation by the calculation unit. First, the position of the load is calculated based on the state (encoder information) of the jib actuator (tilt / tilt drive unit) and the rope length actuator (winding drive unit). In addition, based on the destination information of the load input when the operator inputs the movement of the load, an input (basic input) of a non-controlled state in a linear model in which only the elevation / tilt angle with respect to the jib is changed while keeping the rope length constant is calculated. Furthermore, an input shaping method using a zero vibration input shaper is applied to the basic input to derive a reference control input for obtaining a reference vibration output that absorbs the residual vibration of the load when the change in elevation / tilt ends. This reference control input is temporarily stored in the storage unit to form a normative control model. In addition, the reference vibration output is a vibration behavior due to the reference control input, which can also be calculated in the calculation unit and stored in the storage unit as forming a normative model.

[0063] The calculation unit then compares the dynamics model when the jib elevation / depression angle is changed while changing the rope length with the dynamics model in the reference control model, and derives the control input when the vibration outputs of both are considered to be the same as the final control input. The derived final control input derives an output signal for changing the elevation / depression angle by the elevation / depression control unit in order to control elevation / depression, and also derives an output signal for changing the rope length by the rope control unit in order to control the rope length.

[0064] <Experimental Example 1> Simulation was carried out using the above-mentioned control method. The length of the jib (L B The jib angle and rope length were simultaneously changed while moving the load. The conditions were as shown in the table below.

[0065] [Table 1]

[0066] Under the above conditions, the arrival time of the load (t f ) is the minimum value ((t f ) min ) was obtained. The design parameters (a, t1) and the minimum value of the arrival time ((t f ) min ) and obtained the results shown in the table below.

[0067] [Table 2]

[0068] Based on the above, a simulation of vibration behavior was performed, and the results shown in Fig. 7 were obtained. For comparison, Fig. 7 also shows simulations under the same conditions for the control according to this embodiment (indicated as MRIS in the figure), the case where a ZVDD input shaper based on a robust input shaping method (ZVDD input shaping control: see Non-Patent Document 1) is used (indicated as ZVDD in the figure), and the case where no control is performed (indicated as Non Control in the figure). Note that "MRIS" shown in the figure is an abbreviation for "Mode Reference Input Shaping," which means a model reference type input shaping method, and is a control method proposed by the inventors of the present application.

[0069] 7, the right column shows the change in drum angle and the change in rope length due to the operation of the actuator, and shows the state of the actuator controlled by the control method of this embodiment. However, the change speed and acceleration of the rope length are shown as changing in the negative direction due to winding.

[0070] As shown in Fig. 7, in the case of control according to this embodiment, both the jib elevation angle and the rope length can be changed smoothly, and the vibration behavior (θ) of the load is in a converged state (residual vibration is zero (θ = 0)) when the load movement is completed. In contrast, when the ZVDD input shaper is used, it was found that the vibration does not converge. This is because the linear control method is used as is for nonlinear control, and it shows that the residual vibration cannot be suppressed by the method of simply using a robust input shaper.

[0071] In this simulation, a PC equipped with a 2.7 GHz Intel Core i5-4310M and 8 GB RAM manufactured by Intel was used to calculate the design parameters (a, t1). The calculation speed was 10.76 seconds. Therefore, the time from inputting the target value to completing the movement of the load to the target position can be achieved in an extremely short time of less than 30 seconds. This control time can be said to be short compared to the case where vibration is suppressed by feedback control.

[0072] <Experimental Example 2> Conditions different from the above (except for the length of the jib (L B A simulation was carried out to move the load while changing the jib angle and rope length using the same jib rope length (3m). The conditions are as shown in the table below.

[0073] [Table 3]

[0074] Under the above conditions, the arrival time of the load (t f ) is the minimum value ((t f ) min ) was obtained. The design parameters (a, t1) and the minimum value of the arrival time ((t f ) min ) and obtained the results shown in the table below.

[0075] [Table 4]

[0076] The results of the above simulation are shown in Fig. 8. The contents in the figure are the same as those in Experimental Example 1.

[0077] As is clear from these results, when the control method according to this embodiment is used, the change in the jib elevation angle and rope length is smooth, and the vibration behavior (θ) at the end of the load movement also converges (residual vibration is zero (θ=0)). On the other hand, the vibration using the ZVDD input shaper also did not converge.

[0078] Similarly to Experimental Example 1, the design parameters (a, t1) were calculated using a PC equipped with an Intel 2.7 GHz Intel Core i5-4310M and 8 GB of RAM. In Experimental Example 2, the calculation speed was also short, at 9.53 seconds. As in Experiment 1, if the calculation time is around 10 seconds, in the case of feedforward control as in the present invention, it is within a sufficiently practical range since calculations can be performed on-site in response to changes in conditions and the calculations can be used to operate the crane.

[0079] Therefore, taking Experimental Examples 1 and 2 together, it can be said that when control is performed using the control method according to this embodiment, the time required for movement of the suspended load from input to completion does not require 30 seconds.

[0080] <Modifications, etc.> Although the embodiment of the present invention is as described above, the embodiment is merely an example of the present invention, and the present invention is not limited to the embodiment. Therefore, it is possible to change some of the elements of the present invention or add other elements.

[0081] For example, in the above embodiment, no particular description is given of the movement of the suspended load by the rotation of the crane (rotation of the main body), but the jib crane to which this embodiment can be applied is also capable of rotation, and the rotation can be controlled separately. In this case, the rotation operation and the operation of tilting and lengthening the rope are not to be performed simultaneously from the viewpoint of safety, so each is operated and controlled separately. In other words, vibration control for rotation is performed separately from vibration control for tilting and lengthening the rope.

[0082] Furthermore, naturally, if the load can be moved by changing only the elevation or the length of the rope, vibration control can be performed using a linear model without adopting a nonlinear model. [Explanation of symbols]

[0083] 1 Jib crane 2 Crane Post 3 Main body 4. Jib 5 Actuators (winch, etc.) 6. Hanging rope 7 Hanging load 8 Control device 41 Wire Rope 81 Processing section 82 Servo driver

Claims

1. A control method for reducing residual vibrations occurring in a suspended load when a suspended load is moved to a predetermined position by lifting a jib in a jib crane and winding a rope, comprising: An input of an uncontrolled state in a linear model in which only the elevation angle with respect to the jib is changed while the rope length from the end of the jib to the load is kept constant is determined in advance as a basic input; applying an input shaping method using a zero vibration input shaper to the fundamental input, a vibration output that absorbs the residual vibration of the suspended load when the change in elevation or depression is completed is set as a reference vibration output, and a reference control input for obtaining the reference vibration output is derived; A control model defined by the obtained reference control input and reference vibration output is formed as a reference control model; A dynamic model when changing the jib elevation angle while changing the rope length is compared with a dynamic model in the reference control model, and a control input when the vibration output of both is considered to be the same is derived as a final control input; Activating the jib based on the final control input A method for controlling a jib crane.

2. 2. A method for controlling a jib crane as described in claim 1, wherein the rope length when generating the reference vibration output is set to an intermediate length within a range of planned lengths over which the rope length is changed.

3. The basic input is defined by dividing the continuous jib operating time from the starting state when the jib elevation angle changes into the time from the starting state to any intermediate state, the time from that intermediate state to reaching the target angle, and the time after reaching the target angle, and is defined by the magnitude of the impulse input for each time, and the magnitude of the impulse at each time is limited within a range of conditions that can absorb the residual vibration of the load by an input shaping method using a zero vibration input shaper.

4. A control system for a jib crane controlled by the control method according to any one of claims 1 to 3, a tilt drive unit for tilting the jib; A winding drive unit that winds up the rope that suspends the load from the tip of the jib; In a jib crane equipped with an input unit that specifies the destination of a suspended load, an output unit that outputs control signals to the tilt drive unit and the winding drive unit; a control unit that receives a signal from the input unit and controls the amount of change in the tilt drive unit and the winding drive unit; an output unit that outputs a control signal from the control unit to the elevation drive unit and the winding drive unit, The control unit further includes a calculation unit and a storage unit. The calculation unit is Calculating the position of the suspended load based on the states of the elevation drive unit and the winding drive unit; From the input information on the destination of the load, the uncontrolled input in a linear model in which only the elevation angle of the jib is changed while the rope length from the end of the jib to the load is kept constant is calculated as the basic input, applying an input shaping method using a zero vibration input shaper to the fundamental input to derive a reference control input for obtaining a reference vibration output that absorbs the residual vibration of the suspended load when the change in elevation or depression is completed; A control model defined by the reference control input and the reference vibration output is formed as a normative control model, and a dynamics model when the jib elevation angle is changed while changing the rope length is compared with a dynamics model in the normative control model, and a control input when the vibration output of both is considered to be the same is derived as a final control input; The storage unit stores the results of the calculations performed by the calculation unit. A jib crane control system comprising:

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