Patent Description:
Conventionally, in a crane, vibration occurs in a load being conveyed. Such vibration is vibration as a single pendulum having a load suspended down at a leading end of a wire rope as a mass point, or a double pendulum having a hook portion as a fulcrum, with the acceleration applied during conveyance as a vibromotive force.

Further, in addition to the vibration due to the single pendulum or the double pendulum, vibration due to bending of a structure included in a crane such as a telescopic boom or a wire rope occurs in a load conveyed by the crane including the telescopic boom.

The load suspended down on the wire rope vibrates at a resonance frequency of the single pendulum or the double pendulum, and is conveyed while vibrating at a natural frequency in a hoisting direction of the telescopic boom, a natural frequency in a turning direction, and/or a natural frequency at the time of expanding/contracting vibration due to elongation of the wire rope.

In such a crane, in order to stably lower the load to a predetermined position, an operator needs to perform an operation of canceling the vibration of the load by turning or hoisting the telescopic boom through a manual operation using an operation tool. For this reason, conveyance efficiency of the crane is affected by the magnitude of vibration generated during conveyance or a skill level of the crane operator.

Therefore, there is known a crane that suppresses the vibration of the load and improves the conveyance efficiency by damping a frequency component of a resonance frequency of the load from a conveyance instruction (control signal) of an actuator of the crane (see Patent Literature <NUM>).

A crane device described in Patent Literature <NUM> calculates the resonance frequency from the rope length (hanging length), which is a distance from a center of rotation of oscillation of the wire rope to a center of gravity of the load. Then, the crane device removes a component near the resonance frequency from the conveyance instruction by using a filter unit.

Incidentally, when a resonance frequency of swing of the load from the hanging length is calculated, it is necessary to calculate a length from a boom leading end section to the load. The length from the boom leading end section to the load is a value obtained by adding a length from the boom leading end section to a hook and a length from the hook to the load.

The length from the boom leading end section to the hook can be calculated based on the amount of reeling out of the wire rope (length of the wire rope) and the number of times of winding the wire rope around the hook. However, in practice, in order to calculate the resonance frequency of the swing of the load from the hanging length of the load, the length from the boom leading end section to the hook and the length of the slinging tool to be hung on the hook are required. In this case of acquiring the length of the slinging tool hung on the hook, various measuring devices, etc. for measuring the length of the slinging tool are required. Such a measuring device has a complicated device configuration and increases the manufacturing cost. Therefore, there is a demand for a technology for easily acquiring the length of the slinging tool without requiring various measuring devices, etc. for measuring the length of the slinging tool. <CIT> discloses a crane with a control unit according to the preamble of claim <NUM>, as well as a method executed in said crane.

An object of the invention is to provide a crane capable of easily acquiring a length of a slinging tool according to a lifting load of the crane, and a method for acquiring the length of the slinging tool.

An aspect of a crane according to the invention includes a boom, a wire rope that is suspended down from a leading end section of the boom, a suspender that is fixed to a lower end of the wire rope and is for suspending a slinging tool for hanging a load, a calculation unit that calculates a first load, which is a weight of a member that is suspended down from the suspender, a slinging tool database unit that stores information pertaining to the slinging tool corresponding to the first load, a determination unit that determines whether the load is being suspended from the suspender, and a control unit that acquires the information pertaining to the slinging tool corresponding to the first load from the slinging tool database unit when the load is being suspended, and sets a vertical length of the slinging tool on the basis of the acquired information pertaining to the slinging tool.

A method for acquiring a length of a slinging tool according to the invention is a method for acquiring a vertical length of a slinging tool executed in a crane including a boom, a wire rope that is suspended down from a leading end section of the boom, and a suspender that is fixed to a lower end of the wire rope and is for suspending the slinging tool for hanging a load, the method including calculating a first load, which is a weight of a member that is suspended down from the suspender, acquiring information pertaining to the slinging tool corresponding to the first load from a slinging tool database unit that stores the information pertaining to the slinging tool corresponding to the first load when the load is being suspended, and setting a vertical length of the slinging tool on the basis of the acquired information pertaining to the slinging tool.

According to the invention, it is possible to provide a crane capable of easily acquiring a length of a slinging tool according to a lifting load of the crane, and a method for acquiring the length of the slinging tool.

Hereinafter, a description will be given of a crane <NUM> according to an embodiment of the invention with reference to <FIG> and <FIG>. Note that even though a mobile crane (rough terrain crane) will be described as the crane <NUM> in the present embodiment, a truck crane, etc. may be used.

As illustrated in <FIG>, the crane <NUM> is a mobile crane that can move to an unspecified place. The crane <NUM> has a vehicle <NUM> and a crane device <NUM>.

The vehicle <NUM> conveys the crane device <NUM>. The vehicle <NUM> has a plurality of wheels <NUM> and runs using an engine <NUM> as a power source. The vehicle <NUM> has an outrigger <NUM>. The outrigger <NUM> has a projecting beam and a jack cylinder. The projecting beam can be hydraulically extended to both sides of the vehicle <NUM> in a width direction. The jack cylinder is fixed to a leading end section of the projecting beam and can extend in a direction perpendicular to the ground. The vehicle <NUM> can extend a workable range of the crane <NUM> by extending the outrigger <NUM> in the width direction of the vehicle <NUM> and grounding the jack cylinder.

The crane device <NUM> lifts a load W by a slinging wire rope WR which is an example of a slinging tool. The crane device <NUM> includes a turning table <NUM>, a boom <NUM>, a jib 9a, a main hook block <NUM>, a sub-hook block <NUM>, a hoisting hydraulic cylinder <NUM>, a main winch <NUM>, a main wire rope <NUM>, a sub-winch <NUM>, a sub-wire rope <NUM>, a cabin <NUM>, etc..

The turning table <NUM> supports the crane device <NUM> with respect to the vehicle <NUM> so that the crane device <NUM> can turn. The turning table <NUM> is provided on a frame of the vehicle <NUM> via an annular bearing. The turning table <NUM> is configured to be rotatable around a center of the annular bearing as a center of rotation. The turning table <NUM> has a hydraulic turning hydraulic motor <NUM> that is an actuator. The turning table <NUM> turns in a first direction or a second direction by the turning hydraulic motor <NUM>.

The turning hydraulic motor <NUM> which is an actuator is rotationally operated by a turning valve <NUM> (see <FIG>) which is an electromagnetic proportional switching valve. The turning valve <NUM> can adjust a flow rate of hydraulic oil supplied to the turning hydraulic motor <NUM> to an arbitrary flow rate. That is, the turning table <NUM> is adjusted to an arbitrary turning speed via the turning hydraulic motor <NUM> operated by the turning valve <NUM>. The turning table <NUM> has a turning sensor <NUM> (see <FIG>) that detects a turning position (angle) and a turning speed of the turning table <NUM>.

The boom <NUM> supports the wire rope so that the load W can be lifted. The boom <NUM> includes a plurality of boom members. The boom <NUM> expands and contracts in an axial direction by moving each boom member using an expansion/contraction hydraulic cylinder (not illustrated) that is an actuator. A base end of a base boom member of the boom <NUM> is supported at substantially a center of the turning table <NUM> so that the base end can swing.

An expansion/contraction hydraulic cylinder (not illustrated) which is an actuator is expanded and contracted by an expansion/contraction operation valve <NUM> (see <FIG>) which is an electromagnetic proportional switching valve. The expansion/contraction operation valve <NUM> can adjust a flow rate of hydraulic oil supplied to an expansion/contraction hydraulic cylinder to an arbitrary flow rate.

That is, the boom <NUM> is adjusted to an arbitrary boom length by the expansion/contraction operation valve <NUM>. The boom <NUM> has a boom length detection sensor <NUM> and a weight sensor <NUM> (see <FIG>) which is lifting load detection means. The boom length detection sensor <NUM> detects the length of the boom <NUM>. The weight sensor <NUM> detects a weight Wm of the load W, etc. applied to the main wire rope <NUM> via a main hook 10a. In addition, the weight sensor <NUM> detects a weight Ws of the load W, etc. applied to the sub-wire rope <NUM> via the sub-hook 11a.

Note that a weight Wm·Ws of the load W, etc. refers to, for example, a weight obtained by adding the weight of the load W and a weight of the slinging wire rope WR. In addition, when the main hook 10a is used, the weight sensor <NUM> can detect, as a lifting load, a weight obtained by adding a rope weight corresponding to an amount of reeling out of the main wire rope <NUM>, a weight of the main hook block <NUM>, the weight of the load W, and the weight of the slinging wire rope WR. Note that a sum of the weight of the load W and the weight of the slinging wire rope WR corresponds to an example of a first load.

In addition, when the sub-hook 11a is used, the weight sensor <NUM> can detect, as a lifting load, a weight obtained by adding a rope weight corresponding to an amount of reeling out of the sub-wire rope <NUM>, a weight of the sub-hook block <NUM>, the weight of the load W, and the weight of the slinging wire rope WR.

The jib 9a expands a lift or working radius of the crane device <NUM>. The jib 9a is held by a jib support portion provided on the base boom member of the boom <NUM> in a posture along the base boom member. A base end of the jib 9a is connectable to a jib support portion of a top boom member.

The main hook block <NUM> and the sub-hook block <NUM> are suspenders for suspending the load W. The main hook block <NUM> is provided with a plurality of hook sheaves around which the main wire rope <NUM> is wound, and the main hook 10a for suspending the load W via the slinging wire rope WR. The weight of the main hook block <NUM> may be regarded as the weight including the hook sheaves and the main hook 10a.

The sub-hook block <NUM> is provided with the sub-hook 11a for suspending the load W via the slinging wire rope WR. The weight of the sub-hook block <NUM> may be regarded as the weight including the sub-hook 11a.

The hoisting hydraulic cylinder <NUM>, which is an actuator, raises and lowers the boom <NUM> to hold the posture of the boom <NUM>. The hoisting hydraulic cylinder <NUM> has a cylinder portion and a rod portion. An end section of the cylinder portion is swingably connected to the turning table <NUM>. An end section of the rod portion is swingably connected to the base boom member of the boom <NUM>.

The hoisting hydraulic cylinder <NUM> is expanded and contracted by a hoisting valve <NUM> (see <FIG>) which is an electromagnetic proportional switching valve. The hoisting valve <NUM> can adjust a flow rate of hydraulic oil supplied to the hoisting hydraulic cylinder <NUM> to an arbitrary flow rate. That is, the boom <NUM> is adjusted to an arbitrary hoisting speed by the hoisting valve <NUM>. The boom <NUM> is provided with a hoisting sensor <NUM> (see <FIG>) that detects a hoisting angle of the boom <NUM>.

The main winch <NUM> and the sub-winch <NUM> reels in (winds) and reels out (unwind) the main wire rope <NUM> and the sub-wire rope <NUM>. The main winch <NUM> includes a main drum around which the main wire rope <NUM> is wound, and a main hydraulic motor (not illustrated) which is an actuator that rotationally drives the main drum.

The sub-winch <NUM> includes a sub-drum around which the sub-wire rope <NUM> is wound, and a sub-hydraulic motor (not illustrated) which is an actuator that rotationally drives the sub-drum. Note that in the present embodiment, the main winch <NUM> and the sub-winch <NUM> are provided near a base end section of the boom <NUM>. However, for example, the main winch or the sub-winch may be provided at the leading end section of the boom <NUM>.

The main hydraulic motor is rotated by a main valve <NUM> (see <FIG>) which is an electromagnetic proportional switching valve. The main valve <NUM> can adjust a flow rate of hydraulic oil supplied to the main hydraulic motor to an arbitrary flow rate.

That is, the main winch <NUM> is adjusted to an arbitrary reeling in and reeling out speed by the main valve <NUM>. Similarly, the sub-winch <NUM> is adjusted to an arbitrary reeling in and reeling out speed by the sub-valve <NUM> (see <FIG>), which is an electromagnetic proportional switching valve. The main winch <NUM> is provided with a main reeling out amount detection sensor <NUM>. Similarly, the sub-winch <NUM> is provided with a sub-reeling out amount detection sensor <NUM>.

The cabin <NUM> covers a cockpit. The cabin <NUM> is mounted on the turning table <NUM>. Inside the cabin <NUM>, the cockpit (not illustrated) is provided. In the cockpit, an operation tool for operating driving of the vehicle <NUM>, a turning operation tool <NUM> for operating the crane device <NUM>, a hoisting operation tool <NUM>, an expansion/contraction operation tool <NUM>, a main drum operation tool <NUM>, a sub-drum operation tool <NUM>, etc. are provided (see <FIG>).

The turning operation tool <NUM> controls the turning hydraulic motor <NUM> by operating the turning valve <NUM>. The hoisting operation tool <NUM> controls the hoisting hydraulic cylinder <NUM> by operating the hoisting valve <NUM>. The expansion/contraction operation tool <NUM> controls the expansion/contraction hydraulic cylinder by operating the expansion/contraction operation valve <NUM>.

The main drum operation tool <NUM> controls the main hydraulic motor by operating the main valve <NUM>. The sub-drum operation tool <NUM> controls the sub-hydraulic motor by operating the sub-valve <NUM>.

The crane <NUM> configured as described above can move the crane device <NUM> to an arbitrary position by running the vehicle <NUM>. In addition, the crane <NUM> can change the lift of the crane device <NUM> by raising the boom <NUM> to an arbitrary hoisting angle using the hoisting hydraulic cylinder <NUM> through an operation of the hoisting operation tool <NUM>. In addition, the crane <NUM> can change the working radius of the crane device <NUM> by extending the boom <NUM> to an arbitrary length by operating the expansion/contraction operation tool <NUM>.

In addition, the crane <NUM> can convey the load W by lifting the load W using the main drum operation tool <NUM>, etc. to turn the turning table <NUM> through an operation of the turning operation tool <NUM>.

Next, the control device <NUM> included in the crane device <NUM> will be described with reference to <FIG>. The control device <NUM> may be regarded as an example of the control unit. Note that in <FIG> and <FIG>, the crane device <NUM> is in a state of performing an operation of lifting the load W by the main hook 10a. In the present embodiment, the crane device <NUM> will be specifically described by taking as an example a case where an operation of lifting the load W is performed using the main hook 10a.

As illustrated in <FIG>, the control device <NUM> has a function of controlling the actuator of the crane <NUM> via each operation valve, and a function of acquiring various information of the crane device <NUM> to perform determination/calculation. For example, the control device <NUM> acquires a vertical length h of the slinging tool by determining whether the load W is present (suspended) or the load W is not present and only the main hook block <NUM> is present based on a lifting load by the main wire rope <NUM>.

Here, the vertical length h of the slinging tool in the present embodiment is a vertical height dimension of the slinging tool. Specifically, as illustrated in <FIG>, <FIG>, <FIG>, the vertical length h is a vertical length dimension from an upper end of the slinging wire rope WR hung on the main hook 10a to a lower end of the slinging wire rope WR in a state where both end portions of the slinging wire rope WR are attached to an upper end portion of the load W when the load W is lifted by the main hook 10a using the slinging wire rope WR which is an example of the slinging tool.

The control device <NUM> includes a control signal generation unit 36a, a resonance frequency calculation unit 36b, and a filter unit 36c. The control device <NUM> is provided in the cabin <NUM>. The control device <NUM> may actually have a configuration in which a CPU, a ROM, a RAM, an HDD, etc. are connected by a bus, or may be configured by a one-chip LSI, etc..

The control device <NUM> stores various programs for controlling the operation of the crane device <NUM> and data for obtaining the vertical length h of the slinging tool. In addition, the control device <NUM> stores various programs and data for controlling the operations of the control signal generation unit 36a, the resonance frequency calculation unit 36b, and the filter unit 36c.

The weight sensor <NUM> is connected to the control device <NUM>. For example, the weight sensor <NUM> includes a load cell, and a detection signal thereof is sent to a load determination unit 36d (see <FIG>) of the control device <NUM>. The weight sensor <NUM> corresponds to an example of a lifting load detection unit.

The load determination unit 36d is a part of the control device <NUM>, and is connected to the weight sensor <NUM>. For example, the load determination unit 36d determines whether or not the lifting load detected by the weight sensor <NUM> is equal to or greater than a predetermined threshold value (also referred to as a first threshold value). The load determination unit 36d corresponds to an example of a determination unit.

Although details will be described later, the control device <NUM> includes a slinging tool database unit <NUM> that saves data obtained by associating the load applied to the hook (in the present embodiment, the main hook 10a) with the vertical length h (see <FIG> and <FIG>) of the slinging tool (slinging wire rope WR) corresponding to the load applied to the hook.

Further, the slinging tool database unit <NUM> is configured to be able to output the saved data in response to a request from the control device <NUM>. Note that for example, the "slinging tool corresponding to the load applied to the hook" refers to a slinging tool that is frequently used under a load applied to a predetermined hook.

In addition to the data obtained by associating the load applied to the hook with the vertical length h of the slinging tool corresponding to the load applied to the hook described above, for example, the slinging tool database unit <NUM> saves specification information of various slinging wires.

Examples of the specification information include the weight for each type of slinging wire rope WR (for each applied load shape, for each allowable load, etc.), the suspending angle θw (see <FIG>) at the time of using the slinging wire rope WR (for example, for each weight), a wire length Lw (see <FIG>) of the slinging wire rope WR, a diameter of each type of slinging wire rope WR (for each applied load), etc..

The control signal generation unit 36a is a part of the control device <NUM> and generates a control signal that is a speed instruction for each actuator. The control signal generation unit 36a acquires the operation amount of each operation tool from the turning operation tool <NUM>, the hoisting operation tool <NUM>, the expansion/contraction operation tool <NUM>, the main drum operation tool <NUM>, the sub-drum operation tool <NUM>, etc..

In addition, the control signal generation unit 36a acquires a turning position of the turning table <NUM>, a boom length, a hoisting angle, and the weight Wm·Ws of the load W, etc. from the turning sensor <NUM>, the boom length detection sensor <NUM>, the weight sensor <NUM>, and the hoisting sensor <NUM>.

The control signal generation unit 36a is configured to generate a control signal C(<NUM>) of the turning operation tool <NUM>, a control signal C(<NUM>) ··a control signal C(n) of the hoisting operation tool <NUM> (hereinafter simply collectively referred to as a "control signal C(n)", n is an arbitrary number) from the acquired operation amount of each operation tool or a state of the crane <NUM>.

The resonance frequency calculation unit 36b is a part of the control device <NUM>. The resonance frequency calculation unit 36b calculates a resonance frequency ω(n) of the swing of the load W using the load W suspended down on the main wire rope <NUM> or the sub-wire rope <NUM> as a single pendulum.

The resonance frequency calculation unit 36b acquires the hoisting angle of the boom <NUM> acquired by the control signal generation unit 36a. The resonance frequency calculation unit 36b acquires the amount Lm(n) of reeling out of the main wire rope <NUM> and the amount Ls(n) of reeling out of the sub-wire rope <NUM> (see <FIG>) from the main reeling out amount detection sensor <NUM> or the sub-reeling out amount detection sensor <NUM>. Note that the resonance frequency calculation unit 36b may acquire the amount of reeling out of the wire rope corresponding to one of the main hook and the sub-hook to be used.

When the main hook block <NUM> is used, the resonance frequency calculation unit 36b acquires the hanging number of the main hook block <NUM> from a safety device (not illustrated).

Further, the resonance frequency calculation unit 36b calculates the amount Lm(n) of reeling out of the main wire rope <NUM> from a position where the main wire rope <NUM> is separated from the sheave to the main hook block <NUM> based on the acquired hoisting angle of the boom <NUM> and hanging number of the main hook block <NUM> when the main hook block <NUM> is used. In other words, the resonance frequency calculation unit 36b calculates the length (amount of reeling out) of the main wire rope <NUM> between the sheave and the main hook block <NUM> based on the hoisting angle of the boom <NUM> and the hanging number of the main hook block <NUM> when the main hook block <NUM> is used.

In addition, the resonance frequency calculation unit 36b calculates the amount Ls(n) of reeling out of the sub-wire rope <NUM> from a position where the sub-wire rope <NUM> is separated from the sheave to the sub-hook block <NUM> (see <FIG>). In other words, the resonance frequency calculation unit 36b calculates the length (amount of reeling out) of the sub-wire rope <NUM> between the sheave and the sub-hook block <NUM>.

The filter unit 36c is a part of the control device <NUM>. The filter unit 36c generates a notch filter F(<NUM>) ·F(<NUM>) ··F(n) (hereinafter simply collectively referred to as a "notch filter F(n)", n is an arbitrary number) that attenuates a specific frequency region of a control signal C(<NUM>) ·C(<NUM>) ··C(n).

The filter unit 36c applies the notch filter F(n) to the control signal C(n). The filter unit 36c acquires the turning position of the turning table <NUM>, the boom length, the hoisting angle, the weight Wm·Ws of the load W, etc., the control signal C(<NUM>), the control signal C(<NUM>) ··the control signal C(n) from the control signal generation unit 36a. Further, the filter unit 36c acquires the resonance frequency ω(n) from the resonance frequency calculation unit 36b.

The filter unit 36c applies the notch filter F(<NUM>) to the control signal C(<NUM>) and generates a filtering control signal Cd(<NUM>) in which a frequency component in an arbitrary frequency range is attenuated at an arbitrary ratio with respect to the resonance frequency w(<NUM>) from the control signal C(<NUM>).

Similarly, the filter unit 36c applies the notch filter F(<NUM>) to the control signal C(<NUM>) to generate a filtering control signal Cd(<NUM>). In other words, the filter unit 36c is configured to apply the notch filter F(n) to the control signal C(n) and generate a filtering control signal Cd(n) (hereinafter simply collectively referred to as a "filtering control signal Cd(n)", n is an arbitrary number) in which a frequency component in an arbitrary frequency range is attenuated at an arbitrary ratio with respect to the resonance frequency ω(n) from the control signal C(n).

The filter unit 36c transmits the filtering control signal Cd(n) to the corresponding operation valve among the turning valve <NUM>, the expansion/contraction operation valve <NUM>, the hoisting valve <NUM>, the main valve <NUM>, and the sub-valve <NUM>.

That is, the control device <NUM> is configured to be able to control the turning hydraulic motor <NUM>, which is an actuator, the hoisting hydraulic cylinder <NUM>, and the main hydraulic motor and the sub-hydraulic motor (not illustrated) via each operation valve.

The control signal generation unit 36a is connected to the turning operation tool <NUM>, the hoisting operation tool <NUM>, the expansion/contraction operation tool <NUM>, the main drum operation tool <NUM>, and the sub-drum operation tool <NUM>. The control signal generation unit 36a acquires the operation amount of each of the turning operation tool <NUM>, the hoisting operation tool <NUM>, the main drum operation tool <NUM>, and the sub-drum operation tool <NUM>.

Further, the control signal generation unit 36a is connected to the turning sensor <NUM>, the boom length detection sensor <NUM>, the weight sensor <NUM>, and the hoisting sensor <NUM>. The control signal generation unit 36a acquires the turning position of the turning table <NUM>, the boom length, the hoisting angle, and the weight Wm·Ws of the load W, etc. from each of these sensors.

In addition, the control signal generation unit 36a is connected to the resonance frequency calculation unit 36b. The control signal generation unit 36a acquires the amount Lm(n) of reeling out of the main wire rope <NUM>, the amount Ls(n) of reeling out of the sub-wire rope <NUM> (see <FIG>), and/or the resonance frequency ω(n) from the resonance frequency calculation unit 36b.

The resonance frequency calculation unit 36b is connected to the main reeling out amount detection sensor <NUM>, the sub-reeling out amount detection sensor <NUM>, and the safety device (not illustrated). The resonance frequency calculation unit 36b calculates the amount Lm(n) of reeling out of the main wire rope <NUM> and/or the amount Ls(n) of reeling out of the sub-wire rope <NUM>.

The filter unit 36c is connected to the control signal generation unit 36a. The filter unit 36c acquires the turning position of the turning table <NUM>, the boom length, the hoisting angle, the weight Wm·Ws of the load W, etc., and the control signal C(n) from the control signal generation unit 36a.

Further, the filter unit 36c is connected to the resonance frequency calculation unit 36b. The filter unit 36c can acquire the resonance frequency ω(n) from the resonance frequency calculation unit 36b. Further, the filter unit 36c is connected to the turning valve <NUM>, the expansion/contraction operation valve <NUM>, the hoisting valve <NUM>, the main valve <NUM>, and the sub-valve <NUM>. The filter unit 36c generates and transmits the corresponding filtering control signal Cd(n) to the turning valve <NUM>, the hoisting valve <NUM>, the main valve <NUM>, and the sub-valve <NUM>.

Here, the notch filter F(n) will be described with reference to <FIG>. The notch filter F(n) is a filter that gives a steep attenuation to the control signal C(n) centered around an arbitrary frequency.

As shown in <FIG>, the notch filter F(n) is a filter having a frequency characteristic that attenuates a frequency component of a notch width Bn, which is an arbitrary frequency range centered around an arbitrary center frequency ωc(n), with a notch depth Dn, which is an attenuation ratio of an arbitrary frequency at the center frequency ωc(n).

That is, the frequency characteristic of the notch filter F(n) is determined by the center frequency ωc(n), the notch width Bn, and the notch depth Dn.

The notch filter F(n) has a transfer function H(s) shown in the following Equation (<NUM>). [Equation <NUM>] <MAT>.

In Equation (<NUM>), ωn is a center frequency coefficient ωn corresponding to the center frequency ωc(n) of the notch filter F(n). ζ is a notch width coefficient ζ corresponding to the notch width Bn. δ is a notch depth coefficient δ corresponding to the notch depth Dn.

A characteristic of the notch filter F(n) is represented by a load shake reduction rate determined by the notch width coefficient ζ and the notch depth coefficient δ. The load shake reduction rate is a rate determined by the notch width coefficient ζ and the notch depth coefficient δ in the transfer function H(s) of the notch filter F(n).

The control device <NUM> configured in this way generates the control signal C(n) corresponding to each operation tool based on the operation amounts of the turning operation tool <NUM>, the hoisting operation tool <NUM>, the main drum operation tool <NUM>, and the sub-drum operation tool <NUM> in the control signal generation unit 36a.

The control device <NUM> calculates the amount Lm(n) of reeling out of the main wire rope <NUM> or the amount Ls(n) of reeling out of the sub-wire rope <NUM>, and calculates the resonance frequency ω(n) based on the gravitational acceleration g and the amount Lm(n) of reeling out or the amount Ls(n) of reeling out in the resonance frequency calculation unit 36b.

Further, the control device <NUM> calculates the notch width coefficient ζ and the notch depth coefficient δ corresponding to the control signal C(n) from the control signal C(n), the turning position of the turning table <NUM>, the boom length and the hoisting angle of the boom <NUM>, and the weight Wm·Ws of the load W, etc. in the filter unit 36c.

The control device <NUM> calculates the corresponding center frequency coefficient ωn using the resonance frequency ω(n) calculated by the resonance frequency calculation unit 36b as the reference center frequency ωc(n) of the notch filter F(n).

As shown in <FIG>, the control device <NUM> generates the filtering control signal Cd(n) by applying the notch filter F(n), to which the notch width coefficient ζ, the notch depth coefficient δ, and the center frequency coefficient ωn are applied, to the control signal C(n) in the filter unit 36c.

The filter unit 36c transmits the filtering control signal Cd(n) to the corresponding valve among the turning valve <NUM>, the expansion/contraction operation valve <NUM>, the hoisting valve <NUM>, the main valve <NUM>, and the sub-valve <NUM>, and controls the turning hydraulic motor <NUM>, which is an actuator, the hoisting hydraulic cylinder <NUM>, the main hydraulic motor (not illustrated), and the sub-hydraulic motor (not illustrated).

Next, a method for acquiring the vertical length h of the slinging tool executed by the control device <NUM> will be specifically described with reference to <FIG>.

First, in step S10, for example, the control device <NUM> determines one of the main hook block <NUM> (main hook 10a) and the sub-hook block <NUM> (sub-hook 11a) used to perform a lifting operation from operation states of the main drum operation tool <NUM> and the sub-drum operation tool <NUM>. Then, the control device <NUM> causes a control process to proceed to step S20.

Subsequently, in step S20, the control device <NUM> acquires the amount of reeling out of the wire rope of the used hook. The, the control device <NUM> calculates the weight of the wire rope reeled out from the leading end of the boom <NUM> corresponding to the amount of reeling out. The control device <NUM> calculates the weight of the wire rope reeled out from the leading end of the boom <NUM> based on the acquired amount of reeling out of the wire rope and information pertaining to the stored weight of the wire rope per unit length. Thereafter, the control device <NUM> causes the control process to proceed to step S30.

Subsequently, in step S30, the control device <NUM> sets, as a threshold value, a value obtained by adding the weight of the wire rope reeled out calculated in step S20 to the weight of the used hook block. Then, the control device <NUM> causes the control process to proceed to step S40. Step S30 corresponds to an example of a setting process of setting a predetermined threshold value.

Subsequently, in step S40, the control device <NUM> calculates a lifting load based on a change in the detection value (load) of the weight sensor <NUM>. Then, the control device <NUM> causes the control process to proceed to step <NUM>. Specifically, the control device <NUM> acquires the detection value (load) of the weight sensor <NUM> when the detection value becomes constant as the lifting load. Then, the control device <NUM> causes the control process to proceed to step S50. Step S40 corresponds to an example of a calculation process for calculating the lifting load from the change in the load by the weight sensor <NUM>.

Subsequently, in step S50, the control device <NUM> determines whether or not the lifting load is larger than a predetermined threshold value. As a result, when it is determined that the lifting load is larger than the predetermined threshold value ("YES" in step S50), the control device <NUM> causes the control process to proceed to step S60.

On the other hand, when it is determined that the lifting load is less than or equal to the predetermined threshold value ("NO" in step S50), the control device <NUM> causes the control process to proceed to step S100. Step S50 corresponds to an example of a determination process of determining whether or not the lifting load is larger than the predetermined threshold value. In addition, steps S20 to S50 correspond to an example of a process in which the control unit determines whether or not the crane <NUM> is in a state of lifting a load.

Subsequently, in step S60, the control device <NUM> acquires the load applied to the hook. That is, the control device <NUM> subtracts the rope weight corresponding to the amount of reeling out of the wire rope and the weight of the hook block from the lifting load, and acquires the load applied to the hook. Then, the control device <NUM> causes the control process to proceed to step S70. The control device <NUM> may be regarded as an example of the calculation unit.

In step S70, the control device <NUM> acquires the vertical length h of the slinging tool corresponding to the load applied to the hook from the slinging tool database unit <NUM>. That is, the control device <NUM> sets a slinging tool frequently used under the load according to the load applied to the hook.

As an example, as illustrated in <FIG>, when the slinging tool is two slinging wire ropes WR, the control device <NUM> calculates the vertical length h of the slinging tool based on the preset suspending angle θw corresponding to the slinging wire ropes WR and the wire length Lw when the slinging wire ropes WR are linearly extended (h = Lw × cosθw). Then, the control device <NUM> ends the control process illustrated in <FIG>.

Subsequently, in step S100, the control device <NUM> sets the vertical length h of the slinging tool to zero. Then, the control device <NUM> ends the control process illustrated in <FIG>.

The vertical length h of the slinging tool acquired by the slinging tool length acquisition method according to the present embodiment can be used when the resonance frequency ω(n) of the swing of the load W is calculated based on a hanging length of the load W from the leading end section of the boom <NUM>. Note that a method of calculating the resonance frequency ω(n) may be a known method.

In the crane <NUM> configured in this way, when the lifting load is larger than a predetermined threshold value, the control device <NUM> determines that the load W is being lifted via the slinging wire rope WR. Then, the control device <NUM> acquires, from the slinging tool database unit <NUM>, specifications (suspending angle θw and wire length Lw) of the slinging wire rope WR corresponding to the load applied to the hook calculated based on the lifting load. Then, the control device <NUM> acquires the vertical length h of the slinging wire rope WR based on the acquired specifications. Then, the control device <NUM> sets the acquired value as the vertical length h of the slinging wire rope WR. On the other hand, when the lifting load is less than or equal to the predetermined threshold value, the control device <NUM> determines that the load W is not being lifted via the slinging wire rope WR. Then, the control device <NUM> sets the vertical length h of the slinging wire rope WR to zero. In this way, it is possible to simply and easily acquire the vertical length h of the slinging wire rope WR without the need for various measuring devices, etc. for measuring the vertical length h of the slinging wire rope WR. Furthermore, it is possible to obtain the hanging length of the load W from the leading end section of the boom <NUM> using the vertical length h of the slinging wire rope WR acquired or set in this way. Therefore, the resonance frequency ω(n) of the swing of the load W can be accurately calculated.

Next, a method for acquiring the vertical length h of the slinging tool according to a second embodiment of the invention will be described with reference to <FIG>.

The method for acquiring the vertical length h of the slinging tool according to the second embodiment is implemented by executing the following steps instead of step S70 in the flow of the method for acquiring the vertical length h of the slinging tool according to the first embodiment illustrated in <FIG>. In the following, only steps that are alternatives to step S70 will be described, and since the other steps are the same as those in the first embodiment, a description thereof will be omitted.

In step S72, the control device <NUM> acquires the number of used slinging wire ropes WR input by the operator using input means (not illustrated). Then, the control device <NUM> causes the control process to proceed to step S74.

In step S74, the control device <NUM> calculates the load applied to each of the slinging wire ropes WR based on the load applied to the hook acquired in step S60 and the number of used slinging wire ropes WR acquired in step S72. Then, the control device <NUM> causes the control process to proceed to step S76.

In step S76, the control device <NUM> identifies the used slinging wire rope WR based on the load applied to each of the slinging wire ropes WR acquired in step S74 and the allowable load of the slinging wire ropes WR, etc. Subsequently, the control device <NUM> acquires the wire length Lw and the suspending angle θw determined according to the load applied to the hook from the slinging tool database unit <NUM>. Then, the control device <NUM> causes the control process to proceed to step S78.

In step S78, the control device <NUM> calculates the vertical length h of the slinging wire ropes WR using the wire length Lw and the suspending angle θw of the slinging wire ropes WR acquired in step S76 (h = Lw × cosθw).

In the method for acquiring the vertical length of the slinging tool of the second embodiment, the same effect as that of the method for acquiring the vertical length of the slinging tool of the first embodiment is achieved, and it is possible to acquire the more accurate vertical length h of the slinging wire ropes WR.

An aspect of a crane according to the invention can be configured to include a boom, a wire rope suspended down from a leading end section of the boom so that the wire rope can be freely wound and unwound, a suspender suspended down at a lower end of the wire rope and used to suspend a slinging tool hung on a load, and lifting load detection means that detects a lifting load by the wire rope, in which a resonance frequency of swing of the suspended load determined from the amount of reeling out of the wire rope is calculated, a control signal of an actuator is generated according to an operation of an operation tool, a filtering control signal for the actuator is generated in which a frequency component in an arbitrary frequency range is attenuated at an arbitrary ratio with respect to the resonance frequency from the control signal, and the actuator is controlled.

Claim 1:
A crane (<NUM>) comprising:
a boom (<NUM>);
a wire rope (WR) that is suspended down from a leading end section of the boom (<NUM>);
a suspender (<NUM>,<NUM>) that is fixed to a lower end of the wire rope (WR) and is for suspending a slinging tool for hanging a load (W);
a calculation unit (<NUM>) that calculates a first load, which is a weight of a member that is suspended down from the suspender (<NUM>,<NUM>);
characterized in that
the crane (<NUM>) further comprises:
a slinging tool database unit (<NUM>) that stores information pertaining to the slinging tool corresponding to the first load;
a determination unit (36d) that determines whether the load (W) is being suspended from the suspender (<NUM>,<NUM>); and
a control unit (<NUM>) that acquires the information pertaining to the slinging tool corresponding to the first load from the slinging tool database unit (<NUM>) when the load (W) is being suspended, and sets a vertical length (h) of the slinging tool on the basis of the acquired information pertaining to the slinging tool.