Patent Description:
Conventionally, a crane has been known as a typical work vehicle. The crane is mainly configured by a traveling body and a turning body. The traveling body includes a plurality of wheels and is configured to be able to travel. The turning body includes a boom, a wire rope, a hook, and the like. Such a turning body is configured to be able to carry a load. Further, such a crane includes an actuator which is used for moving a load and a control device which can instruct an operating state of the actuator.

The US patent application publication <CIT> discloses a crane. The crane disclosed in <CIT> includes a operable functional unit, an actuator, a generation unit, a filter unit, and a control unit. The actuator drives the operable functional unit. The generation unit generates a control signal in control of causing the operable functional unit to automatically stop. The filter unit filters the control signal. The control unit control the actuator on the basis of the control signal filtered by the filter unit.

By the way, a crane is proposed in which the control device creates a filtering control signal and controls the actuator on the basis of the filtering control signal (see Patent Literature <NUM>). Here, the filtering control signal means a signal to apply a filter having a predetermined characteristic to the basic control signal of the actuator. For example, the filter may be a notch filter. The notch filter has a characteristic that an attenuation rate becomes higher as a frequency approaches a resonance frequency in an arbitrary range around the resonance frequency. Incidentally, the resonance frequency is calculated on the basis of the suspension length of the hook.

In such a crane, in order to stop a moving load at a predetermined location, it is necessary to start deceleration appropriately before the predetermined location. However, the location corresponding to "appropriately before the predetermined location" varies depending on the working radius of the boom, the suspension length of the hook, the weight of the load, and the like. Therefore, it has been difficult to reliably stop the load at the predetermined location. Further, there is a concern that when the load passes the predetermined location, the load collides with a building or the like. In this regard, there is a demand for a crane which is capable of decelerating a load while suppressing the swing of the load and stopping the load at the predetermined location when automatically stopping the movement of the load.

Further, the document <CIT>discloses a crane that includes a boom, and a hook suspended by a wire rope which is stretched over the boom, the crane comprising an operable functional unit; an actuator for driving the operable functional unit; a generation unit; a control unit that is configured to control the actuator so as to decelerate the operable functional unit, then controls the actuator so as to maintain the speed of the operable functional unit; wherein the speed is determined on the basis of at least one of the working radius of the boom, the suspension length of the hook, and the weight of the load suspended by the hook; and the actuator is any one of a hydraulic motor which turns a boom, a hydraulic cylinder which extends/retracts the boom, a hydraulic cylinder which hoists the boom, and a hydraulic motor which lifts/ lowers a hook.

An object of the present invention is to provide a crane which is capable of decelerating a load while suppressing swing of the load and stopping the load at a predetermined location when automatically stopping movement of the load.

According to a solution, the present invention provides a crane in accordance with independent claim <NUM>. Further solutions and aspects of the present invention are set forth in the dependent claims, the drawings and the following description.

One aspect of a crane according to the present invention includes:.

According to the present invention, it is possible to provide a crane which is capable of decelerating a load while suppressing swing of the load and stopping the load at a predetermined location when automatically stopping movement of the load.

The technical idea disclosed in this application can be applied to various cranes in addition to a crane <NUM> described below.

First, the crane <NUM> will be described with reference to <FIG>.

The crane <NUM> is mainly configured by a traveling body <NUM> and a turning body <NUM>.

The traveling body <NUM> includes a pair of right and left front tires <NUM> and a rear tire <NUM>. In addition, the traveling body <NUM> is provided with an outrigger <NUM> which is grounded to achieve stability when performing a work of carrying a load W. Incidentally, in the traveling body <NUM>, the turning body <NUM> supported on the upper part thereof can be turned by an actuator.

The turning body <NUM> is provided with a boom <NUM> so as to project forward from the rear part thereof. Therefore, the boom <NUM> can be turned by an actuator (see arrow A). Further, the boom <NUM> can be extended/retracted by an actuator (see arrow B). The boom <NUM> corresponds to an example of a operable functional unit.

The boom <NUM> can be hoisted by an actuator (see arrow C). In addition, a wire rope <NUM> is stretched over the boom <NUM>. A winch <NUM> around which a wire rope <NUM> is wound is arranged on the base end side of the boom <NUM>, and a hook <NUM> is suspended by the wire rope <NUM> on the tip end side of the boom <NUM>. The winch <NUM> corresponds to an example of the operable functional unit.

The winch <NUM> is configured integrally with an actuator, and the wire rope <NUM> can be wound and unwound. Therefore, the hook <NUM> can be lifted/lowered by the actuator (see arrow D).

Next, an automatic stop system will be described with reference to <FIG>. However, this automatic stop system is an example of a conceivable configuration and is not limited to this.

The automatic stop system is mainly configured by a control device <NUM>. A turning operation tool <NUM>, a telescopic operation tool <NUM>, a hoisting operation tool <NUM>, and a winding operation tool <NUM> are connected to the control device <NUM>. Further, a turning valve <NUM>, a telescoping valve <NUM>, a hoisting valve <NUM>, and a winding valve <NUM> are connected to the control device <NUM>.

A weight sensor <NUM>, a turning sensor <NUM>, a telescoping sensor <NUM>, a hoisting sensor <NUM>, and a winding sensor <NUM> are connected to the control device <NUM>. Incidentally, the weight sensor <NUM> can detect the weight of the load W. Therefore, the control device <NUM> can recognize the weight of the load W.

As described above, the boom <NUM> can be turned by the actuator (see arrow A in <FIG>). In this application, a turning hydraulic motor <NUM> corresponds to an example of an actuator. The turning hydraulic motor <NUM> is appropriately operated by the turning valve <NUM> which is an electromagnetic proportional switching valve.

In other words, the turning hydraulic motor <NUM> is appropriately operated when the turning valve <NUM> switches the flow direction of a hydraulic oil or adjusts the flow rate of the hydraulic oil. Incidentally, the turning angle and the turning speed of the boom <NUM> are detected by the turning sensor <NUM>. Therefore, the control device <NUM> can recognize the turning angle and the turning speed of the boom <NUM>.

As described above, the boom <NUM> can be extended/retracted by the actuator (see arrow B in <FIG>). A telescoping hydraulic cylinder <NUM> corresponds to an example of the actuator. The telescoping hydraulic cylinder <NUM> is appropriately operated by the telescoping valve <NUM> which is an electromagnetic proportional switching valve.

In other words, the telescoping hydraulic cylinder <NUM> is appropriately operated when the telescoping valve <NUM> switches the flow direction of the hydraulic oil or adjusts the flow rate of the hydraulic oil. Incidentally, the telescoping length and telescoping speed of the boom <NUM> are detected by the telescoping sensor <NUM>. Therefore, the control device <NUM> can recognize the telescoping length and the telescoping speed of the boom <NUM>.

As described above, the boom <NUM> can be hoisted by the actuator (see arrow C in <FIG>). A hoisting hydraulic cylinder <NUM> corresponds to an example of the actuator. The hoisting hydraulic cylinder <NUM> is appropriately operated by the hoisting valve <NUM> which is an electromagnetic proportional switching valve.

In other words, the hoisting hydraulic cylinder <NUM> is appropriately operated when the hoisting valve <NUM> switches the flow direction of the hydraulic oil or adjusts the flow rate of the hydraulic oil. Incidentally, the hoisting angle and the hoisting speed of the boom <NUM> are detected by the hoisting sensor <NUM>. Therefore, the control device <NUM> can recognize the hoisting angle and the hoisting speed of the boom <NUM>.

In addition, as described above, the hook <NUM> can be lifted/lowered by the actuator (see arrow D in <FIG>). A winding hydraulic motor <NUM> corresponds to an example of the actuator. The winding hydraulic motor <NUM> is appropriately operated by the winding valve <NUM> which is an electromagnetic proportional switching valve.

In other words, the winding hydraulic motor <NUM> is appropriately operated when the winding valve <NUM> switches the flow direction of the hydraulic oil or adjusts the flow rate of the hydraulic oil. Incidentally, a suspension length L (see <FIG>) or the lifting/lowering speed of the hook <NUM> is detected by the winding sensor <NUM>. Therefore, the control device <NUM> can recognize the suspension length L or the lifting/lowering speed of the hook <NUM>.

By the way, the control device <NUM> controls respective actuators (<NUM>, <NUM>, <NUM>, and <NUM>) via the various valves <NUM> to <NUM>. The control device <NUM> includes a basic control signal creation unit 20a, a resonance frequency calculation unit 20b, a filter coefficient calculation unit 20c, and a filtering control signal creation unit 20d.

The basic control signal creation unit 20a creates a basic control signal S which is a speed command for each actuator (<NUM>, <NUM>, <NUM>, and <NUM>) (see <FIG>). The basic control signal creation unit 20a recognizes the operation amounts of the various operation tools <NUM> to <NUM> by the operators and creates the basic control signal S for each situation. The basic control signal creation unit 20a corresponds to an example of a generation unit. The generation unit may be regarded as included in the control device <NUM>. However, the generation unit may not be included in the control device <NUM>.

Specifically, the basic control signal creation unit 20a creates the basic control signal S according to the operation amount of the turning operation tool <NUM>, the basic control signal S according to the operation amount of the telescopic operation tool <NUM>, the basic control signal S according to the operation amount of the hoisting operation tool <NUM>, the basic control signal S according to the operation amount of the winding operation tool <NUM>, and/or the like.

The resonance frequency calculation unit 20b is a unit for calculating a resonance frequency ω which is the frequency of the swing of the load W caused by the operation of each actuator (<NUM>, <NUM>, <NUM>, and <NUM>). The resonance frequency calculation unit 20b recognizes the suspension length L of the hook <NUM> on the basis of the posture of the boom <NUM> and the unwinding amount of the wire rope <NUM> and calculates the resonance frequency ω for each situation.

Specifically, the resonance frequency calculation unit 20b calculates the resonance frequency ω on the basis of the following equation using the suspension length L of the hook <NUM> and a gravitational acceleration g.

The filter coefficient calculation unit 20c calculates a center frequency coefficient ωn, a notch width coefficient ζ, and a notch depth coefficient δ of a transfer coefficient H(s) included in a notch filter F described later. The filter coefficient calculation unit 20c calculates the corresponding center frequency coefficient ωn centering on the resonance frequency ω calculated by the resonance frequency calculation unit 20b.

The filter coefficient calculation unit 20c calculates the notch width coefficient ζ and the notch depth coefficient δ corresponding to each basic control signal S. Incidentally, the transfer coefficient H(s) is expressed by the following equation using the center frequency coefficient ωn, the notch width coefficient ζ, and the notch depth coefficient δ.

The filtering control signal creation unit 20d creates the notch filter F and also applies the notch filter F to the basic control signal S to create a filtering control signal Sf (see <FIG>). The filtering control signal creation unit 20d creates the notch filter F by obtaining the various coefficients ωn, ζ, and δ from the filter coefficient calculation unit 20c. The filtering control signal creation unit 20d corresponds to an example of a filter unit. The filter unit may be regarded as included in the control device <NUM>. However, the filter unit may not be included in the control device <NUM>.

The notch filter F is expressed by a load swing reduction rate determined on the basis of the notch width coefficient ζ and the notch depth coefficient δ. Further, the filtering control signal creation unit 20d obtains the basic control signal S from the basic control signal creation unit 20a and applies the notch filter F to the basic control signal S to create the filtering control signal Sf.

More specifically, the filtering control signal creation unit 20d creates the filtering control signal Sf on the basis of the basic control signal S and the notch filter F according to the operation amount of the turning operation tool <NUM> and the like. Further, the filtering control signal creation unit 20d creates the filtering control signal Sf on the basis of the basic control signal S and the notch filter F according to the operation amount of the telescopic operation tool <NUM> and the like. Further, the filtering control signal creation unit 20d creates the filtering control signal Sf on the basis of the basic control signal S and the notch filter F according to the operation amount of the hoisting operation tool <NUM> and the like. Further, the filtering control signal creation unit 20d creates the filtering control signal Sf on the basis of the basic control signal S and the notch filter F according to the operation amount of the winding operation tool <NUM> and the like.

With such a configuration, the control device <NUM> can control the various valves <NUM> to <NUM> on the basis of the filtering control signal Sf. As a result, the control device <NUM> controls each actuator (<NUM>, <NUM>, <NUM>, and <NUM>) on the basis of the filtering control signal Sf. The control device <NUM> corresponds to an example of a control unit.

Next, the notch filter F and the filtering control signal Sf will be described with reference to <FIG> and <FIG>.

The notch filter F has a characteristic that an attenuation rate becomes higher as a frequency approaches a resonance frequency ω in an arbitrary range around the resonance frequency ω. The arbitrary range around the resonance frequency ω is expressed as a notch width Bn. The difference in the amount of attenuation in the notch width Bn is expressed as a notch depth Dn.

Therefore, the notch filter F is specified by the resonance frequency ω, the notch width Bn, and the notch depth Dn. Incidentally, the notch depth Dn is determined on the basis of the notch depth coefficient δ. Therefore, in the case of the notch depth coefficient δ = <NUM>, the gain characteristic at the resonance frequency ω is -∞ dB, and in the case of the notch depth coefficient δ = <NUM>, the gain characteristic at the resonance frequency ω is <NUM> dB.

The filtering control signal Sf is a speed command transmitted to each actuator (<NUM>, <NUM>, <NUM>, and <NUM>). The filtering control signal Sf corresponding to the acceleration of the load W has a characteristic that is moderate in acceleration compared to the basic control signal S, and is temporarily decelerated and then accelerated again (see a X section in <FIG>). Here, the reason of the temporary deceleration is to suppress the swing of the load W during acceleration.

The filtering control signal Sf corresponding to the deceleration of the load W has a characteristic that is moderate or the same in deceleration compared to the basic control signal S, and is temporarily accelerated and then decelerated again (see a Y section in <FIG>). Here, the reason of the temporary acceleration is to suppress the swing of the load W during deceleration.

The filtering control signal Sf has a characteristic that a low-speed command maintains after the load W is decelerated (see a Z section in <FIG>). The reason for doing this will be described later.

Next, a movement allowable area Rp and a movement restriction area Rr of the load W will be described with reference to <FIG>. The movement allowable area Rp corresponds to an example of the first area. The movement restriction area Rr corresponds to an example of the second area.

The movement allowable area Rp indicates an area where the movement of the load W is permitted at a work site. In the movement allowable area Rp, the notch depth coefficient δ is <NUM> or a value close to <NUM>. Accordingly, it is possible to suppress the swing of the load W with respect to the operation of the operator. However, the notch depth coefficient δ may be set to <NUM> or a value close to <NUM> so that a prompt reaction to the operation of the operator can be obtained.

The movement restriction area Rr indicates an area where movement of the load W is not permitted at the work site. In the movement restriction area Rr, the load W does not enter the area, and thus, the notch depth coefficient δ and the like are not defined. Further, the movement restriction area Rr is provided so as to surround a building B. Therefore, the collision between the load W and the building B can be prevented.

Incidentally, in a case where the load W in the movement allowable area Rp is moving toward the movement restriction area Rr, it is necessary to decelerate the load W while suppressing the swing of the load W and stop the load at the boundary between the movement allowable area Rp and the movement restriction area Rr. In this application, the boundary between the movement allowable area Rp and the movement restriction area Rr is defined as a predetermined location P. However, the predetermined location P is not limited. The predetermined location P may be any location where the load W is desired to be stopped. The control device <NUM> may have a function of calculating the predetermined location P on the basis of predetermined information. The predetermined information may be detection values of various sensors provided on the crane <NUM>, imaging data of a camera, and/or location information obtained by GPS.

Hereinafter, a control mode (also referred to as automatic stop control) for automatically stopping the movement of the load W will be described with reference to <FIG>.

First, an example will be described in which the load W is moving toward the movement restriction area Rr by the turning operation of the boom <NUM>. (A) to (D) of <FIG> schematically illustrate the movement of the load W.

In step S11, the control device <NUM> sets a control start location for automatic stop. In other words, the control device <NUM> sets the control start location at which the turning operation of the boom <NUM> is stopped. The control start location is determined by the turning speed of the boom <NUM>, a working radius R of the boom <NUM> (see <FIG>), the suspension length L of the hook <NUM>, the weight of the load W, and the like. The control start location may be regarded as corresponding to a start location of a first deceleration signal section of the basic control signal S described later.

In step S12, the control device <NUM> creates the basic control signal S of the turning hydraulic motor <NUM> (see <FIG>). The basic control signal S is created such that a constant low speed command maintains from a section related to the deceleration of the turning speed (an inclined section of the basic control signal S).

In other words, the basic control signal S includes the first deceleration signal section for decelerating the turning speed of the boom <NUM> from a first speed to a second speed at a predetermined deceleration rate (also referred to as a first deceleration rate) and a first constant-speed signal section for maintaining the turning speed of the boom <NUM> at a predetermined speed (that is, the second speed).

The predetermined speed (second speed) may be, for example, the lowest speed that can be realized as the turning speed of the boom <NUM>. In a state where the turning speed of the boom <NUM> is a predetermined speed (second speed), it may be regarded that the hydraulic oil of the minimum flow rate is supplied to the actuator (the turning hydraulic motor <NUM> in this example).

Incidentally, the basic control signal S is created on the basis of a program used during automatic stop. The program is stored in the control device <NUM> in advance.

The temporal length of the first constant-speed signal section of the basic control signal S may be infinite. Further, the first constant-speed signal section of the basic control signal S may be set in advance. The time length of the first constant-speed signal section of the basic control signal S may be longer than a time required until the load W reaches the predetermined location P after the automatic stop control starts, and the speed (the turning speed of the boom <NUM> in this example) of the operable functional unit (the boom <NUM> in this example) reaches the second speed.

In step S12, the control device <NUM> may generate the first deceleration signal section of the basic control signal S and may not generate the first constant-speed signal section. In other words, the first deceleration signal section and the first constant-speed signal section of the basic control signal S may not be generated at the same time.

In step S12, in a case where the control device <NUM> does not generate the first constant-speed signal section of the basic control signal S, the control device <NUM> may generates the first constant-speed signal section of the basic control signal S in real time in step S14 described later. In this case, the first constant-speed signal section may or may not be subjected to a filtering process by the notch filter F.

In step S13, the control device <NUM> applies the notch filter F to the basic control signal S to create the filtering control signal Sf (see <FIG>). The filtering control signal Sf is created such that a low speed command maintains from a section related to the deceleration of the turning speed (an inclined section of the filtering control signal Sf) (see Z section in <FIG>). In other words, the filtering control signal Sf includes a second deceleration signal section corresponding to the first deceleration signal section of the basic control signal S and a second constant-speed signal section corresponding to the first constant-speed signal section of the basic control signal S.

Then, the control device <NUM> controls the turning hydraulic motor <NUM> on the basis of the filtering control signal Sf. As a result, it is possible to suppress the swing of the load W due to the deceleration of the turning speed (see (A) to (C) in <FIG>).

In other words, when the turning speed of the boom <NUM> is reduced, the load W starts to swing due to inertia (see (A) in <FIG>). In this regard, by temporarily increasing the turning speed of the boom <NUM>, the boom <NUM> is caught up, and the swing of the load W is suppressed (see (B) in <FIG>). Then, thereafter, the load W is decelerated again in the state of suppressing the swing of the load W (see (C) in <FIG>).

In step S14, the control device <NUM> causes the boom <NUM> to continue the low-speed turning operation. Specifically, in step S14, the control device <NUM> controls the actuator (the turning hydraulic motor <NUM> in this example) on the basis of the second constant-speed signal section among the second deceleration signal section and the second constant-speed signal section (see arrow Z in <FIG>) of the filtering control signal Sf. As a result, the load W approaches the predetermined location P without swinging (see (D) in <FIG>). Incidentally, as described above, the control device <NUM> may generate the first constant-speed signal section of the basic control signal S in real time in step S14. Further, in step S14, the control device <NUM> may or may not perform the filtering process by the notch filter F on the first constant-speed signal section of the basic control signal S generated in real time.

Incidentally, the turning speed at this time may be determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W (for example, determined by assigning at least one to a predetermined function: see double-dashed lines M and N in <FIG>). Such a procedure is performed in order to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W.

In step S15, the control device <NUM> determines whether or not the load W reaches the predetermined location P. In a case where it is determined that the load W reaches the predetermined location P ("YES" in step S15), the control process proceeds to step S16. The predetermined location P may be regarded as corresponding to one example of a location which satisfies a prescribed condition. Incidentally, in step S15, the control device <NUM> may determine whether or not the load W reaches a location separated from the predetermined location P by a predetermined distance to the movement allowable area Rp side. In this case, the location separated by the predetermined distance from the predetermined location P to the movement allowable area Rp side may be regarded as corresponding to one example of the location which satisfies the prescribed condition. The location separated by the predetermined distance from the predetermined location P to the movement allowable area Rp side may be a location which allows the load W to stop at the predetermined location P when the supply of the hydraulic oil to the actuator is stopped.

On the other hand, in a case where it is determined that the load W does not reach the predetermined location P ("NO" in step S15), the control process continues the low-speed turning operation in step S14. Accordingly, the load W does not stop before the predetermined location P and is reliably moved to the predetermined location P. Further, since the load W does not swing greatly, the load does not pass the predetermined location P to enter the movement restriction area Rr.

In step S16, the control device <NUM> stops the turning operation of the boom <NUM>. In this way, the load W reliably stops at the predetermined location P. Incidentally, the amount of movement of the load W after the control device <NUM> issues an instruction to zero the turning speed of the boom <NUM> may not be zero. For example, the amount of movement can be calculated in advance on the basis of a flow amount (a movement distance until stopping the turning operation after issuing an instruction) calculated on the basis of the second speed corresponding to the first constant-speed signal section of the basic control signal S. When a distance from a boundary location between the movement allowable area Rp (first area) and the movement restriction area Rr (second area) to an object (building B) is set larger than the flow amount calculated in this way, it is possible to prevent the load W from colliding with the object. Further, in step S16, when the control device <NUM> controls the actuator (the turning hydraulic motor <NUM> in this example) to zero the speed (the turning speed of the boom <NUM> in this example) of the operable functional unit (the boom <NUM> in this example), a stop control signal (the section that drops vertically from the second speed to zero in <FIG>) for zeroing the speed of the operable functional unit may or may not be subjected to a filtering process by the notch filter F. In the control for zeroing the speed of the operable functional unit, when the stop control signal which is not subjected to the filtering process is used, the flow amount of the load W or the boom <NUM> can be set to zero or almost zero. The stop control signal may be generated by the control device <NUM> (specifically, the basic control signal creation unit 20a) when the load W reaches the predetermined location P in step S15.

As described above, this crane <NUM> includes the actuator (turning hydraulic motor <NUM>) which is used for moving the load W and the control device <NUM> which can instruct the operating state of the actuator (<NUM>). Then, when automatically stopping the movement of the load W, the control device <NUM> applies the notch filter F to the basic control signal S of the actuator (<NUM>) to create the filtering control signal Sf. Next, the control device <NUM> controls the actuator (<NUM>) on the basis of the filtering control signal Sf to reduce the moving speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed movement and stops the load at the predetermined location P.

Specifically, the control device <NUM> controls the turning hydraulic motor <NUM> on the basis of the filtering control signal Sf to reduce the turning speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed turning operation and stops the load at the predetermined location P.

According to the crane <NUM> as described above, when the turning operation of the boom <NUM> is automatically stopped, it is possible to decelerate the load W while suppressing the swing of the load W and stop the load at the predetermined location P.

In the crane <NUM>, the turning speed in the low-speed turning operation is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W. According to such a crane <NUM>, it is possible to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W and stop the load.

By the way, in the crane <NUM>, in order to suppress the swing of the load W caused by the turning operation of the boom <NUM>, the frequency of the swing of the load W is set to the resonance frequency ω. However, in order to suppress the swing of the boom <NUM> itself caused by the turning operation of the boom <NUM>, the frequency of the swing of the boom <NUM> may be set to the resonance frequency ω. Further, the resonance frequency ω may be set in consideration of the frequency of the swing of the load W and the frequency of the swing of the boom <NUM>.

Next, an example will be described in which the load W is moving toward the movement restriction area Rr due to the telescopic operation of the boom <NUM>. Here, the description will be given using <FIG> together with <FIG>. <FIG> schematically illustrate the movement of the load W. Incidentally, although the telescopic operation of the boom <NUM> is described as an extension operation, the same is applied to a retraction operation.

In step S11, the control device <NUM> sets a control start location for automatic stop. In other words, the control device <NUM> sets the control start location at which the extension operation of the boom <NUM> is stopped. The control start location is determined by the working radius R of the boom <NUM> (see <FIG>), the suspension length L of the hook <NUM>, the weight of the load W, and the like in addition to the extension speed of the boom <NUM>.

In step S12, the control device <NUM> creates the basic control signal S for the telescoping hydraulic cylinder <NUM> (see <FIG>). The basic control signal S is created such that a constant low speed command maintains from a section related to the deceleration of the extension speed (an inclined section of the basic control signal S).

In step S13, the control device <NUM> applies the notch filter F to the basic control signal S to create the filtering control signal Sf (see <FIG>). The filtering control signal Sf is created such that a low speed command maintains from a section related to the deceleration of the extension speed (an inclined section of the filtering control signal Sf) (see Z section in <FIG>).

Then, the control device <NUM> controls the telescoping hydraulic cylinder <NUM> on the basis of the filtering control signal Sf. As a result, it is possible to suppress the swing of the load W due to the deceleration of the extension speed (see (A) to (C) in <FIG>).

In other words, when the extension speed of the boom <NUM> is reduced, the load W starts to swing due to inertia (see (A) in <FIG>). In this regard, by temporarily increasing the extension speed of the boom <NUM>, the boom <NUM> is caught up, and the swing of the load W is suppressed (see (B) in <FIG>). Then, thereafter, the load W is decelerated again in the state of suppressing the swing of the load W (see (C) in <FIG>).

In step S14, the control device <NUM> causes the boom <NUM> to continue the low-speed extension operation. In other words, since the filtering control signal Sf is created such that the low speed command maintains from the section related to the deceleration of the extension speed (see Z section in <FIG>), the control device <NUM> controls the telescoping hydraulic cylinder <NUM> on the basis of such a section.

As a result, the load W approaches the predetermined location P without swinging (see (D) in <FIG>). Incidentally, the extension speed at this time is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W (for example, determined by assigning at least one to a predetermined function: see double-dashed lines M and N in <FIG>). Such a procedure is performed in order to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W.

In step S15, the control device <NUM> determines whether or not the load W reaches the predetermined location P. In a case where it is determined that the load W reaches the predetermined location P ("YES" in step S15), the control process proceeds to step S16. On the other hand, in a case where it is determined that the load W does not reach the predetermined location P ("NO" in step S15), the control process continues a low-speed moving operation (an extension operation in this example) in step S14.

Accordingly, the load W is reliably moved to the predetermined location P without stopping before the predetermined location P. Further, since the load W does not swing greatly, the load does not pass the predetermined location P to enter the movement restriction area Rr.

In step S16, the control device <NUM> stops the extension operation of the boom <NUM>. In this way, the load W reliably stops at the predetermined location P.

As described above, this crane <NUM> includes the actuator (telescoping hydraulic cylinder <NUM>) which is used for moving the load W and the control device <NUM> which can instruct the operating state of the actuator (<NUM>). When automatically stopping the movement of the load W, the control device <NUM> applies the notch filter F to the basic control signal S of the actuator (<NUM>) to create the filtering control signal Sf. Next, the control device <NUM> controls the actuator (<NUM>) on the basis of the filtering control signal Sf to reduce the moving speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed movement and stops the load at the predetermined location P.

Specifically, the control device <NUM> controls the telescoping hydraulic cylinder <NUM> on the basis of the filtering control signal Sf to reduce the telescoping speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed telescopic operation and stops the load at the predetermined location P. According to the crane <NUM> as described above, when the telescopic operation of the boom <NUM> is automatically stopped, it is possible to decelerate the load W while suppressing the swing of the load W and stop the load at the predetermined location P.

In the crane <NUM>, the telescoping speed in the low-speed telescopic operation is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W. According to such a crane <NUM>, it is possible to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W and stop the load.

By the way, in the crane <NUM>, in order to suppress the swing of the load W caused by the telescopic operation of the boom <NUM>, the frequency of the swing of the load W is set to the resonance frequency ω. However, in order to suppress the swing of the boom <NUM> itself caused by the telescopic operation of the boom <NUM>, the frequency of the swing of the boom <NUM> may be set to the resonance frequency ω. Further, the resonance frequency ω may be set in consideration of the frequency of the swing of the load W and the frequency of the swing of the boom <NUM>.

Next, an example will be described in which the load W is moving toward the movement restriction area Rr due to the hoisting operation of the boom <NUM>. Here, the description will be given with reference to <FIG> together with <FIG>. <FIG> schematically illustrate the movement of the load W. Incidentally, the hoisting operation of the boom <NUM> will be described as a standing operation, but the same is applied to a laying operation.

In step S11, the control device <NUM> sets a control start location for automatic stop. In other words, the control device <NUM> sets the control start location at which the standing operation of the boom <NUM> is stopped. The control start location is determined by the working radius R of the boom <NUM> (see <FIG>), the suspension length L of the hook <NUM>, the weight of the load W, and the like in addition to the standing speed of the boom <NUM>.

In step S12, the control device <NUM> creates the basic control signal S for the hoisting hydraulic cylinder <NUM> (see <FIG>). The basic control signal S is created such that a constant low speed command maintains from a section related to the deceleration of the standing speed (an inclined section of the basic control signal S). Incidentally, the basic control signal S is created on the basis of a program used during automatic stop. The program is stored in the control device <NUM> in advance.

In step S13, the control device <NUM> applies the notch filter F to the basic control signal S to create the filtering control signal Sf (see <FIG>). The filtering control signal Sf is created such that a low speed command maintains from a section related to the deceleration of the standing speed (an inclined section of the filtering control signal Sf) (see Z section in <FIG>).

Then, the control device <NUM> controls the hoisting hydraulic cylinder <NUM> on the basis of the filtering control signal Sf. As a result, it is possible to suppress the swing of the load W due to the deceleration of the standing speed (see (A) to (C) in <FIG>).

In other words, when the standing speed of the boom <NUM> is reduced, the load W starts to swing due to inertia (starts to swing due to the bending of the wire rope <NUM>: see (A) in <FIG>). In this regard, the standing speed of the boom <NUM> is temporarily increased to catch up with the boom <NUM> and suppress the swing of the load W (see (B) in <FIG>). Then, thereafter, the load W is decelerated again in the state of suppressing the swing of the load W (see (C) in <FIG>).

In step S14, the control device <NUM> causes the boom <NUM> to continue the low-speed standing operation. In other words, since the filtering control signal Sf is created such that the low speed command maintains from the section related to the deceleration of the standing speed (see Z section in <FIG>), the control device <NUM> controls the hoisting hydraulic cylinder <NUM> on the basis of such a section.

As a result, the load W approaches the predetermined location P without swinging (see (D) in <FIG>). Incidentally, the standing speed at this time is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W (for example, determined by assigning at least one to a predetermined function: see double-dashed lines M and N in <FIG>). Such a procedure is performed in order to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W.

In step S15, the control device <NUM> determines whether or not the load W reaches the predetermined location P. In a case where it is determined that the load W reaches the predetermined location P ("YES" in step S15), the control process proceeds to step S16. On the other hand, in a case where it is determined that the load W does not reach the predetermined location P ("NO" in step S15), the control process continues the low-speed standing operation in step S14. Accordingly, the load W is reliably moved to the predetermined location P without stopping before the predetermined location P. Further, since the load W does not swing greatly, the load does not pass the predetermined location P to enter the movement restriction area Rr.

In step S16, the control device <NUM> stops the standing operation of the boom <NUM>. In this way, the load W reliably stops at the predetermined location P.

As described above, this crane <NUM> includes the actuator (hoisting hydraulic cylinder <NUM>) which is used for moving the load W and the control device <NUM> which can instruct the operating state of the actuator (<NUM>). Then, when automatically stopping the movement of the load W, the control device <NUM> applies the notch filter F to the basic control signal S of the actuator (<NUM>) to create the filtering control signal Sf. Next, the control device <NUM> controls the actuator (<NUM>) on the basis of the filtering control signal Sf to reduce the moving speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed movement and stops the load at the predetermined location P.

Specifically, the control device <NUM> controls the hoisting hydraulic cylinder <NUM> on the basis of the filtering control signal Sf to reduce the hoisting speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed hoisting operation and stops the load at the predetermined location P. According to the crane <NUM> as described above, when the hoisting operation of the boom <NUM> is automatically stopped, it is possible to decelerate the load W while suppressing the swing of the load W and stop the load at the predetermined location P.

In the crane <NUM>, the hoisting speed in the low-speed hoisting operation is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W. According to such a crane <NUM>, it is possible to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W and stop the load.

By the way, in the crane <NUM>, in order to suppress the swing of the load W caused by the hoisting operation of the boom <NUM>, the frequency of the swing of the load W is set to the resonance frequency ω. However, in order to suppress the swing of the boom <NUM> itself caused by the hoisting operation of the boom <NUM>, the frequency of the swing of the boom <NUM> may be set to the resonance frequency ω. Further, the resonance frequency ω may be set in consideration of the frequency of the swing of the load W and the frequency of the swing of the boom <NUM>.

Next, an example will be described in which the load W is moving toward the movement restriction area Rr due to the lifting/lowering operation of the hook <NUM>. Here, the description will be given with reference to <FIG> together with <FIG>. <FIG> schematically illustrate the movement of the load W. Incidentally, although the lifting/lowering operation of the hook <NUM> is described as a lifting operation, the same is applied to a lowering operation.

In step S11, the control device <NUM> sets a control start location for automatic stop. In other words, the control device <NUM> sets the control start location at which the lifting operation of the hook <NUM> is stopped. The control start location is determined by the working radius R of the boom <NUM> (see <FIG>), the suspension length L of the hook <NUM>, the weight of the load W, and the like in addition to the lifting speed of the hook <NUM>.

In step S12, the control device <NUM> creates the basic control signal S of the winding hydraulic motor <NUM> (see <FIG>). The basic control signal S is created such that a constant low speed command maintains from a section related to the deceleration of the lifting speed (an inclined section of the basic control signal S). Incidentally, the basic control signal S is created on the basis of a program used during automatic stop. The program is stored in the control device <NUM> in advance.

In step S13, the control device <NUM> applies the notch filter F to the basic control signal S to create the filtering control signal Sf (see <FIG>). The filtering control signal Sf is created such that a low speed command maintains from a section related to the deceleration of the lifting speed (an inclined section of the filtering control signal Sf) (see Z section in <FIG>).

Then, the control device <NUM> controls the winding hydraulic motor <NUM> on the basis of the filtering control signal Sf. As a result, it is possible to suppress the swing of the load W due to the deceleration of the lifting speed (see (A) to (C) in <FIG>).

In other words, when the lifting speed of the hook <NUM> is reduced, the load W starts to swing due to inertia (starts to swing due to the bending of the wire rope <NUM>: see (A) in <FIG>). In this regard, the lifting speed of the hook <NUM> is temporarily increased to stretch the wire rope <NUM> and suppress the swing of the load W (see (B) in <FIG>). Then, thereafter, the load W is decelerated again in the state of suppressing the swing of the load W (see (C) in <FIG>).

In step S14, the control device <NUM> causes the hook <NUM> to continue the low-speed lifting operation. In other words, since the filtering control signal Sf is created such that the low speed command maintains from the section related to the deceleration of the lifting speed (see Z section in <FIG>), the control device <NUM> controls the winding hydraulic motor <NUM> on the basis of such a section.

As a result, the load W approaches the predetermined location P without swinging (see (D) in <FIG>). Incidentally, the lifting speed at this time is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W (for example, determined by assigning at least one to a predetermined function: see double-dashed lines M and N in <FIG>). Such a procedure is performed in order to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W.

In step S15, the control device <NUM> determines whether or not the load W reaches the predetermined location P. In a case where it is determined that the load W reaches the predetermined location P ("YES" in step S15), the control process proceeds to step S16.

On the other hand, in a case where it is determined that the load W does not reach the predetermined location P ("NO" in step S15), the control process continues the low-speed lifting operation in step S14. Accordingly, the load W does not stop before the predetermined location P and is reliably moved to the predetermined location P. Further, since the load W does not swing greatly, the load does not pass the predetermined location P to enter the movement restriction area Rr.

In step S16, the control device <NUM> stops the lifting operation of the hook <NUM>. In this way, the load W reliably stops at the predetermined location P.

As described above, the crane <NUM> includes the actuator (winding hydraulic motor <NUM>) which is used for moving the load W and the control device <NUM> which can instruct the operating state of the actuator (<NUM>). Then, when automatically stopping the movement of the load W, the control device <NUM> applies the notch filter F to the basic control signal S of the actuator (<NUM>) to create the filtering control signal Sf. Next, the control device <NUM> controls the actuator (<NUM>) on the basis of the filtering control signal Sf to reduce the moving speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed movement and stops the load at the predetermined location P.

Specifically, the control device <NUM> controls the winding hydraulic motor <NUM> on the basis of the filtering control signal Sf to reduce the lifting/lowering speed while suppressing the swing of the load W. Thereafter, the control device <NUM> continues the low-speed lifting/lowering operation and stops the load at the predetermined location P. According to the crane <NUM> as described above, when the lifting/lowering operation of the hook <NUM> is automatically stopped, it is possible to decelerate the load W while suppressing the swing of the load W and stop the load at the predetermined location P.

In the crane <NUM>, the lifting/lowering speed in the low-speed lifting/lowering operation is determined on the basis of at least one of the working radius R of the boom <NUM>, the suspension length L of the hook <NUM>, and the weight of the load W. According to such a crane <NUM>, it is possible to move the load W to the predetermined location P as quickly as possible while appropriately suppressing the swing of the load W and stop the load.

By the way, in the crane <NUM>, in order to suppress the swing of the load W caused by the lifting/lowering operation of the hook <NUM>, the frequency of the swing of the load W is set to the resonance frequency ω. However, in order to suppress the swing caused by the expansion/retraction of the wire rope <NUM> caused by the lifting/lowering operation of the hook <NUM>, the frequency of the expansion/retraction of the wire rope <NUM> may be set to the resonance frequency ω. Further, the resonance frequency ω may be set in consideration of the frequency of the swing of the load W and the frequency of the expansion/retraction of the wire rope <NUM>.

Claim 1:
A crane (<NUM>) that includes a boom (<NUM>), and a hook (<NUM>) suspended by a wire rope (<NUM>) which is stretched over the boom (<NUM>), the crane (<NUM>) comprising:
an operable functional unit (<NUM>, <NUM>);
an actuator (<NUM>, <NUM>, <NUM>, <NUM>) for driving the operable functional unit (<NUM>, <NUM>);
a generation unit (20a) that, in control of causing the operable functional unit to automatically stop, is configured to generate a first control signal including a first deceleration signal section including a control signal for decelerating a speed of the operable functional unit (<NUM>, <NUM>) from a first speed to a second speed and a first constant-speed signal section including a control signal for maintaining the speed of the operable functional unit (<NUM>, <NUM>) at the second speed;
a filter unit (20d) for filtering at least the first deceleration signal section in the first control signal to generate a second control signal; and
a control unit (<NUM>) that is configured to control the actuator (<NUM>, <NUM>, <NUM>, <NUM>) so as to decelerate the operable functional unit (<NUM>, <NUM>) on the basis of the second control signal, then controls the actuator (<NUM>, <NUM>, <NUM>, <NUM>) so as to maintain the speed of the operable functional unit (<NUM>, <NUM>) at the second speed, and control the actuator (<NUM>, <NUM>, <NUM>, <NUM>) so as to zero the speed of the operable functional unit (<NUM>, <NUM>) in a case where it is determined that a load suspended from the crane (<NUM>) moves to a location satisfying a prescribed condition,
wherein the second speed is determined on the basis of at least one of the working radius of the boom (<NUM>), the suspension length of the hook (<NUM>), and the weight of the load (W) suspended by the hook (<NUM>); and
the actuator (<NUM>, <NUM>, <NUM>, <NUM>) is any one of a hydraulic motor (<NUM>) which turns a boom (<NUM>), a hydraulic cylinder (<NUM>) which extends/retracts the boom (<NUM>), a hydraulic cylinder (<NUM>) which hoists the boom (<NUM>), and a hydraulic motor (<NUM>) which lifts/lowers a hook (<NUM>).