Patent Description:
Conventionally, as mobile cranes or the like, a crane in which actuators are remotely manipulated has been proposed. In such a crane, the relative positional relationship between the crane and a remote manipulation terminal changes according to a working situation. For this reason, an operator needs to manipulate manipulation tools of the remote manipulation terminal while keeping considering the relative positional relationship between the crane and the remote manipulation terminal. To meet this need, a remote manipulation terminal and a crane are known, which enable easy and simple manipulation of the crane by causing a manipulation direction of a manipulation tool of the remote manipulation terminal to match an operating direction of the crane regardless of the relative positional relationship between the crane and the remote manipulation terminal. For example, see Patent Literature (hereinafter, referred to as "PTL") <NUM>).

A remote manipulation apparatus (remote manipulation terminal) described in PTL <NUM> transmits to a crane a laser beam or the like having high straightness as a reference signal. Control apparatus <NUM> on the crane side receives the reference signal from the remote manipulation apparatus to identify the direction of the remote manipulation apparatus, and causes the coordinate system of the crane to match the coordinate system of the remote manipulation apparatus. Thus, the crane is manipulated by a manipulative command signal from the remote manipulation apparatus that is generated with reference to a load. In other words, actuators of the crane are controlled based on commands on the moving direction of and moving speed of the load, and it is thus possible to intuitively manipulate the crane without paying attention to the operating speed, the operating amount, the operating timing, and the like of each of the actuators.

Based on the manipulative command signal of a manipulation section, the remote manipulation apparatus transmits, to the crane, a speed signal related to a manipulation speed and a directional signal related to a manipulation direction. Accordingly, in the crane, discontinuous acceleration is sometimes caused so as to swing the load at the start or stop of movement in which the speed signal from the remote manipulation apparatus is input in the form of a process function. Moreover, since the crane performs a control using the speed signal and the directional signal from the remote manipulation apparatus as a speed signal and a directional signal for the tip of a boom on the assumption that the tip of the boom is always vertically above the load, it is impossible to prevent the occurrence of a positional shift and/or a swing of the load caused by the influence of a wire rope.

<CIT> discloses a crane that controls an actuator of a boom based on a target signal related to a moving direction and a speed of a load suspended from the boom by a wire rope, the crane comprising:a swivel angle detection means of the boom;a luffing angle detection means of the boom;and a control apparatus, wherein the control apparatus computes a current position of a boom tip relative to the reference position from a swivel angle detected by the swivel angle detection means, a luffing angle detected by the luffing angle detection means, computes a let-out amount of the wire rope and generates an operation signal for the actuator.

An object of the present invention is to provide a crane and a method of controlling the crane which allow a load to move along a target course while reducing a swing of the load when an actuator is controlled with reference to the load.

The technical problem to be solved by the present invention is as described above, and a solution to this problem will be described next.

That is, the crane of the present invention is a crane that controls an actuator of a boom based on a target speed signal related to a moving direction and a speed of a load suspended from the boom by a wire rope, the crane including: a swivel angle detection means of the boom; a luffing angle detection means of the boom; an extension/retraction length detection means of the boom; and a load position detection means that detects a current position of the load relative to a reference position, in which it is preferable that the target speed signal is converted into a target position of the load relative to the reference position, a current position of a boom tip relative to the reference position is computed from a swivel angle detected by the swivel angle detection means, a luffing angle detected by the luffing angle detection means, and an extension/retraction length detected by the extension/retraction length detection means, a let-out amount of the wire rope is computed from the current position of the load detected by the load position detection means and the current position of the boom tip, a direction vector of the wire rope is computed from the current position of the load and the target position of the load, a target position of the boom tip for the target position of the load is computed from the let-out amount and the direction vector of the wire rope, and an operation signal for the actuator is generated based on the target position of the boom tip.

In the crane of the present invention, the target speed signal is converted into the target position of the load by integrating the target speed signal and attenuating a frequency component in a predetermined frequency range.

In the crane of the present invention, a relationship between the target position of the boom tip and the target position of the load is expressed by the following Equation <NUM> based on the target position of the load, a weight of the load, and a spring constant of the wire rope, and the target position of the boom tip is computed by the following Equation <NUM> that is a function of time for the load:
[<NUM>]<MAT>
[<NUM>]<MAT> wherein "f" denotes a tension of the wire rope, "kf' denotes the spring constant, "m" denotes a mass of the load, "q" denotes the current position or the target position of a tip of the boom, "p" denotes the current position or the target position of the load, "<NUM>" denotes the let-out amount of the wire rope, and "g" denotes gravitational acceleration.

The method of controlling a crane of the present invention is a method according to claim <NUM>.

The present invention produces effects as described below.

In the crane and the method of controlling the crane of the present invention, the direction vector of the wire rope is computed from the current position and the target position of a load and the current position of the boom tip, and the target position of the boom tip is computed from the let-out length and the direction vector of the wire rope, so that the crane is manipulated with reference to the load, and the boom is controlled such that the load moves along the target course. It is thus possible to move the load along the target course while reducing the swing of the load, when controlling the actuator with reference to the load.

In the crane of the present invention, since the frequency component including a singular point caused by a differential operation for computation of the target position of the boom is attenuated, the boom is stably controlled. It is thus possible to move the load along the target course while reducing the swing of the load, when controlling the actuator with reference to the load.

In the crane of the present invention, an inverse dynamics model is constructed with reference to the load, the direction vector of the wire rope is computed from the current position of the load and the current position of the boom tip, and the target position of the boom for the target position of the load is computed from the let-out length and the direction vector of the wire rope, so that there is no error that could be caused in a transitional state during acceleration, deceleration, or the like. It is thus possible to move the load along the target course while reducing the swing of the load, when controlling the actuator with reference to the load.

Hereinafter, crane <NUM> that is a mobile crane (rough terrain crane) will be described as a working vehicle according to one embodiment of the present invention with reference to <FIG> and <FIG>. Note that, although the present embodiment will be described in relation to a crane (rough terrain crane) as a working vehicle, the working vehicle may also be an all-terrain crane, a truck crane, a truck loader crane, an aerial work vehicle, or the like.

As illustrated in <FIG>, crane <NUM> is a mobile crane that can be moved to an unspecified place. Crane <NUM> includes vehicle <NUM>, crane apparatus <NUM> that is a working apparatus, and remote manipulation terminal <NUM> (see <FIG>) with which crane apparatus <NUM> is remotely manipulatable.

Vehicle <NUM> carries crane apparatus <NUM>. Vehicle <NUM> includes a plurality of wheels <NUM>, and travels using engine <NUM> as a power source. Vehicle <NUM> is provided with outriggers <NUM>. Outriggers <NUM> are composed of projecting beams hydraulically extendable on both sides of vehicle <NUM> in the width direction and hydraulic jack cylinders extendable in the direction vertical to the ground. Vehicle <NUM> can extend a workable region of crane <NUM> by extending outriggers <NUM> in the width direction of vehicle <NUM> and bringing the jack cylinders into contact with the ground.

Crane apparatus <NUM> hoists up load W with a wire rope. Crane apparatus <NUM> includes swivel base <NUM>, boom <NUM>, jib 9a, main hook block <NUM>, sub hook block <NUM>, hydraulic luffing cylinder <NUM>, main winch <NUM>, main wire rope <NUM>, sub winch <NUM>, sub wire rope <NUM>, cabin <NUM>, and the like.

Swivel base <NUM> allows crane apparatus <NUM> to swivel. Swivel base <NUM> is disposed on a frame of vehicle <NUM> via an annular bearing. Swivel base <NUM> is configured to be rotatable around the center of the annular bearing serving as a rotational center. Swivel base <NUM> is provided with hydraulic swivel motor <NUM> that is an actuator. Swivel base <NUM> is configured to swivel in one and the other directions by hydraulic swivel motor <NUM>.

Swivel-base cameras 7b, which are monitoring apparatuses, capture images of obstacles and people around swivel base <NUM>. Swivel-base cameras 7b are disposed on both the left and right sides of the front of swivel base <NUM> and on both the left and right sides of the rear of swivel base <NUM>. Swivel-base cameras 7b capture images of the periphery of where each of the swivel-base cameras is installed, to cover the entire circumference of swivel base <NUM> as a monitoring area. Further, swivel-base cameras 7b disposed respectively on both the left and right sides of the front of swivel base <NUM> are configured to be usable as a set of stereo cameras. In other words, swivel-base camera 7b at the front of swivel base <NUM> can be configured to be used as a set of stereo cameras, so as to serve as a load position detection means that detects positional information of suspended load W. Note that, the load position detection means may also be configured by boom camera 9b described below. The load position detection means may be any means such as a millimeter-wave radar, a GNSS apparatus, or the like which is capable of detecting the positional information of load W.

Hydraulic swivel motor <NUM> that is an actuator is manipulated to rotate by using swivel valve <NUM> (see <FIG>) that is an electromagnetic proportional switching valve. Swivel valve <NUM> can control the flow rate of an operating oil supplied to hydraulic swivel motor <NUM> to any flow rate. That is, swivel base <NUM> is configured to be controllable via hydraulic swivel motor <NUM> manipulated to rotate by using swivel valve <NUM> such that the swivel speed of swivel base <NUM> is any swivel speed. Swivel base <NUM> is provided with swivel sensor <NUM> (see <FIG>) that detects the swivel angle θz (angle) and swivel speed of swivel base <NUM>.

Boom <NUM>, which is a boom, supports the wire rope such that load W can be hoisted. Boom <NUM> is composed of a plurality of boom members. Boom <NUM> is disposed such that the base end of a base boom member can be swung at a substantial center of swivel base <NUM>. Boom <NUM> is configured to be extendible and retractable in the axial direction by moving the boom members by a hydraulic extension/retraction cylinder (not illustrated) that is an actuator. In addition, boom <NUM> is provided with jib 9a.

The hydraulic extension/retraction cylinder (not illustrated) that is an actuator is manipulated to extend and retract by using extension/retraction valve <NUM> (see <FIG>) that is an electromagnetic proportional switching valve. Extension/retraction valve <NUM> can control the flow rate of an operating oil supplied to the hydraulic extension/retraction cylinder to any flow rate. Boom <NUM> is provided with extension/retraction sensor <NUM> for detecting the length of boom <NUM> and vehicle-side azimuth sensor <NUM> for detecting an azimuth with respect to the tip of boom <NUM> as a center.

Boom camera 9b (see <FIG>), which is a sensing apparatus, captures images of load W and of the features around load W. Boom camera 9b is disposed on the tip portion of boom <NUM>. Boom camera 9b is configured to capture images of the features and topography around load W and crane <NUM> from vertically above load W.

Main hook block <NUM> and sub hook block <NUM> are for suspending load W. Main hook block <NUM> is provided with a plurality of hook sheaves around which main wire rope <NUM> is wound, and main hook 10a for suspending load W. Sub hook block <NUM> is provided with sub hook 11a for suspending load W.

Hydraulic luffing cylinder <NUM> that is an actuator luffs up or down boom <NUM>, and holds the attitude of boom <NUM>. In hydraulic luffing cylinder <NUM>, an end of the cylinder part is swingably coupled to swivel base <NUM>, and an end of the rod part is swingably coupled to the base boom member of boom <NUM>. Hydraulic luffing cylinder <NUM> is manipulated to extend or retract by luffing valve <NUM> (see <FIG>) that is an electromagnetic proportional switching valve. Luffing valve <NUM> can control the flow rate of an operating oil supplied to hydraulic luffing cylinder <NUM> to any flow rate. Boom <NUM> is provided with luffing sensor <NUM> (see <FIG>) for detecting luffing angle θx.

Main winch <NUM> and sub winch <NUM> pull in (wind) or let out (unwind) main wire rope <NUM> and sub wire rope <NUM>, respectively. Main winch <NUM> has a configuration in which a main drum around which main wire rope <NUM> is wound is rotated by using a main hydraulic motor (not illustrated) that is an actuator, and sub winch <NUM> has a configuration in which a sub drum around which sub wire rope <NUM> is wound is rotated by using a sub hydraulic motor (not illustrated) that is an actuator.

The main hydraulic motor is manipulated to rotate by main valve <NUM> (see <FIG>) that is an electromagnetic proportional switching valve. Main winch <NUM> is configured to be capable of being manipulated, by controlling the main hydraulic motor using main valve <NUM>, such that the pulling-in and letting-out speeds are any speeds. Similarly, sub winch <NUM> is configured to be capable of being manipulated, by controlling the sub hydraulic motor using sub valve <NUM> (see <FIG>) that is an electromagnetic proportional switching valve, such that the pulling-in and letting-out speeds are any speeds. Main winch <NUM> and sub winch <NUM> are provided with winding sensors <NUM> (see <FIG>) for detecting let-out amounts <NUM> of main wire rope <NUM> and sub wire rope <NUM>, respectively.

Cabin <NUM> covers an operator compartment. Cabin <NUM> is mounted on swivel base <NUM>. Cabin <NUM> is provided with an operator compartment that is not illustrated. The operator compartment is provided with manipulation tools for traveling manipulation of vehicle <NUM>, and swivel manipulation tool <NUM>, luffing manipulation tool <NUM>, extension/retraction manipulation tool <NUM>, main-drum manipulation tool <NUM>, sub-drum manipulation tool <NUM>, and the like for manipulating crane apparatus <NUM> (see <FIG>). Swivel hydraulic motor <NUM> is manipulatable with swivel manipulation tool <NUM>. Luffing hydraulic cylinder <NUM> is manipulatable with luffing manipulation tool <NUM>. The hydraulic extension/retraction cylinder is manipulatable with extension/retraction manipulation tool <NUM>. The main hydraulic motor is manipulatable with main-drum manipulation tool <NUM>. The sub hydraulic motor is manipulatable with sub-drum manipulation tool <NUM>.

Communication device <NUM> (see <FIG>) receives a control signal from remote manipulation terminal <NUM>, and transmits control information or the like from crane apparatus <NUM>. Communication device <NUM> is disposed in cabin <NUM>. Communication device <NUM> is configured to transfer the control signal or the like to control apparatus <NUM> via a communication line (not illustrated) when receiving the control signal or the like from remote manipulation terminal <NUM>. Further, communication device <NUM> is configured to transfer the control information from control apparatus <NUM>, image i1 from swivel-base cameras 7b, and image i2 from boom camera 9b to remote manipulation terminal <NUM> via the communication line (not illustrated). Here, the control signal is a signal including at least one of a manipulation signal for controlling crane <NUM>, target speed signal Vd, target course signal Td, operation signal Md, and the like.

Vehicle-side azimuth sensor <NUM>, which is an azimuth detection means, detects an azimuth with respect to the tip of boom <NUM> of crane apparatus <NUM> as a center. Vehicle-side azimuth sensor <NUM> is composed of a triaxial type azimuth sensor. Vehicle-side azimuth sensor <NUM> detects terrestrial magnetism to compute the absolute azimuth. Vehicle-side azimuth sensor <NUM> is disposed at the tip portion of boom <NUM>.

Control apparatus <NUM> controls the actuators of crane <NUM> via the manipulation valves as illustrated in <FIG>. Control apparatus <NUM> is disposed inside cabin <NUM>. Substantively, control apparatus <NUM> may have a configuration in which a CPU, ROM, RAM, HDD, and/or the like are connected to one another via a bus, or may be configured to consist of a one-chip LSI or the like. Control apparatus <NUM> stores various programs and/or data in order to control the operation of the actuators, the switching valves, the sensors, and/or the like.

Control apparatus <NUM> is connected to swivel-base cameras 7b, boom camera 9b, swivel manipulation tool <NUM>, luffing manipulation tool <NUM>, extension/retraction manipulation tool <NUM>, main-drum manipulation tool <NUM>, and sub-drum manipulation tool <NUM>, and is capable of obtaining image i1 from swivel-base cameras 7b, image i2 from boom camera 9b, and the manipulation amount of each of swivel manipulation tool <NUM>, luffing manipulation tool <NUM>, main-drum manipulation tool <NUM>, and sub-drum manipulation tool <NUM>.

Control apparatus <NUM> is connected to communication device <NUM> to be capable of obtaining the control signal from remote manipulation terminal <NUM> and transmitting the control information from crane apparatus <NUM>, image i1 from swivel-base cameras 7b, image i2 from boom camera 9b, and the like.

Control apparatus <NUM> is connected to swivel valve <NUM>, extension/retraction valve <NUM>, luffing valve <NUM>, main valve <NUM>, and sub valve <NUM>, and is capable of transmitting operation signals Md to swivel valve <NUM>, luffing valve <NUM>, main valve <NUM>, and sub valve <NUM>.

Control apparatus <NUM> is connected to swivel sensor <NUM>, extension/retraction sensor <NUM>, vehicle-side azimuth sensor <NUM> and luffing sensor <NUM>, and is capable of obtaining swivel angle θz of swivel base <NUM>, extension/retraction length Lb, luffing angle θx, and an azimuth with respect to the tip of boom <NUM> as the center.

Control apparatus <NUM> generates operation signal Md corresponding to each of the manipulation tools based on the manipulation amount of each of swivel manipulation tool <NUM>, luffing manipulation tool <NUM>, main-drum manipulation tool <NUM>, and sub-drum manipulation tool <NUM>.

Crane <NUM> configured as described above is capable of moving crane apparatus <NUM> to any position by causing vehicle <NUM> to travel. Crane <NUM> is also capable of extending the lifting height and/or the operating radius of crane apparatus <NUM>, for example, by luffing up boom <NUM> to any luffing angle θx with hydraulic luffing cylinder <NUM> by manipulation of luffing manipulation tool <NUM>, and/or by extending boom <NUM> to any length of boom <NUM> by manipulation of extension/retraction manipulation tool <NUM>. Crane <NUM> is also capable of carrying load W by hoisting up load W with sub-drum manipulation tool <NUM> and/or the like, and causing swivel base <NUM> to swivel by manipulation of swivel manipulation tool <NUM>.

Next, remote manipulation terminal <NUM> will be described with reference to <FIG>, <FIG>, <FIG>.

As illustrated in <FIG>, remote manipulation terminal <NUM> is used for remote manipulation of crane <NUM>. Remote manipulation terminal <NUM> includes: housing <NUM>; terminal-side azimuth sensor <NUM> (see <FIG>); suspended-load movement manipulation tool <NUM>, terminal-side swivel manipulation tool <NUM>, terminal-side extension/retraction manipulation tool <NUM>, terminal-side main-drum manipulation tool <NUM>, terminal-side sub-drum manipulation tool <NUM>, terminal-side luffing manipulation tool <NUM>, terminal-side display apparatus <NUM>, terminal-side communication device <NUM>, and terminal-side control apparatus <NUM> (see <FIG> and <FIG>) disposed on a manipulation surface of housing <NUM>; and the like. Remote manipulation terminal <NUM> transmits to crane apparatus <NUM> target speed signal Vd of load W that is generated by manipulation of suspended-load movement manipulation tool <NUM> or any of the manipulation tools.

Housing <NUM> is a main component of remote manipulation terminal <NUM>. Housing <NUM> is formed as a housing having a size that can be held by the operator's hand. Suspended-load movement manipulation tool <NUM>, terminal-side swivel manipulation tool <NUM>, terminal-side extension/retraction manipulation tool <NUM>, terminal-side main-drum manipulation tool <NUM>, terminal-side sub-drum manipulation tool <NUM>, terminal-side luffing manipulation tool <NUM>, terminal-side display apparatus <NUM>, and terminal-side communication device <NUM> (see <FIG> and <FIG>) are installed on the manipulation surface of housing <NUM>.

Terminal-side azimuth sensor <NUM>, which is an azimuth detection means, detects an azimuth with reference to an upward direction in plan view of the manipulation surface of remote manipulation terminal <NUM> (hereinafter, such an upward direction is simply referred to as "upward direction"). Terminal-side azimuth sensor <NUM> is composed of a triaxial type azimuth sensor. Terminal-side azimuth sensor <NUM> detects terrestrial magnetism to compute the absolute azimuth. Terminal-side azimuth sensor <NUM> is disposed inside of housing <NUM>.

Suspended-load movement manipulation tool <NUM> is a tool with which an instruction for moving load W at any speed in any direction in any horizontal plane is input. Suspended-load movement manipulation tool <NUM> is composed of a manipulation stick erected substantially vertically from the manipulation surface of housing <NUM> and a sensor (not illustrated) for detecting the tilt direction and the tilt amount of the manipulation stick. Suspended-load movement manipulation tool <NUM> is configured such that the manipulation stick can be manipulated to be tilted in any direction. Suspended-load movement manipulation tool <NUM> is configured to transmit to terminal-side control apparatus <NUM> a manipulation signal for the tilt direction and the tilt amount of the manipulation stick detected by the sensor (not illustrated).

Terminal-side swivel manipulation tool <NUM> is a tool with which an instruction for swiveling crane apparatus <NUM> at any moving speed in any moving direction is input. Terminal-side swivel manipulation tool <NUM> is composed of a manipulation stick erected substantially vertically from the manipulation surface of housing <NUM> and a sensor (not illustrated) for detecting the tilt direction and the tilt amount of the manipulation stick. Terminal-side swivel manipulation tool <NUM> is configured to be tiltable in a direction for instructing left swivel and in a direction for instructing right swivel.

Terminal-side extension/retraction manipulation tool <NUM> is a tool with which an instruction for extension/retraction of boom <NUM> at any speed is input. Terminal-side extension/retraction manipulation tool <NUM> is composed of a manipulation stick erected from the manipulation surface of housing <NUM> and a sensor (not illustrated) for detecting the tilt direction and the tilt amount of the manipulation stick. Terminal-side extension/retraction manipulation tool <NUM> is configured to be tiltable in a direction for instructing extension and in a direction for instructing retraction.

Terminal-side main-drum manipulation tool <NUM> is a tool with which an instruction for rotating main winch <NUM> in any direction at any speed is input. Terminal-side main-drum manipulation tool <NUM> is composed of a manipulation stick erected from the manipulation surface of housing <NUM> and a sensor (not illustrated) for detecting the tilt direction and the tilt amount of the manipulation stick. Terminal-side main-drum manipulation tool <NUM> is configured to be tiltable in a direction for instructing winding of main wire rope <NUM> and in a direction for instructing unwinding of main wire rope <NUM>. Terminal-side sub-drum manipulation tool <NUM> is similarly configured.

Terminal-side luffing manipulation tool <NUM> is a tool with which an instruction for luffing boom <NUM> at any speed is input. Terminal-side luffing manipulation tool <NUM> is composed of a manipulation stick erected from the manipulation surface of housing <NUM> and a sensor (not illustrated) for detecting the tilt direction and the tilt amount of the manipulation stick. Terminal-side luffing manipulation tool <NUM> is configured to be tiltable in a direction for instructing luffing up and in a direction for instructing luffing down.

Terminal-side display apparatus <NUM> is for displaying various information such as postural information of crane <NUM>, information on load W, and/or the like. Terminal-side display apparatus <NUM> is configured by an image display apparatus such as a liquid crystal screen or the like. Terminal-side display apparatus <NUM> is disposed on the manipulation surface of housing <NUM>. Terminal-side display apparatus <NUM> displays an azimuth with reference to the upward direction of remote manipulation terminal <NUM>. The indication of the azimuth is rotationally displayed in conjunction with the rotation of remote manipulation terminal <NUM>.

As illustrated in <FIG>, terminal-side communication device <NUM> receives the control information and the like of crane apparatus <NUM>, and transmits the control information and the like from remote manipulation terminal <NUM>. Terminal-side communication device <NUM> is installed inside housing <NUM>. Terminal-side communication device <NUM> is configured to transmit, to terminal-side control apparatus <NUM>, image i1, image i2, the control signal, and the like from crane apparatus <NUM> upon receiving the images, the control signal, and the like from crane apparatus <NUM>. Terminal-side communication device <NUM> is also configured to transmit the control information, image i1 and image i2 from terminal-side control apparatus <NUM> to control apparatus <NUM> of crane <NUM>.

Terminal-side control apparatus <NUM>, which is a controller, controls remote manipulation terminal <NUM>. Terminal-side control apparatus <NUM> is disposed inside housing <NUM> of remote manipulation terminal <NUM>. Substantively, terminal-side control apparatus <NUM> may have a configuration in which a CPU, ROM, RAM, HDD, and/or the like are connected to one another via a bus, or may be configured to consist of a one-chip LSI or the like. Terminal-side control apparatus <NUM> stores various programs and data in order to control the operation of suspended-load movement manipulation tool <NUM>, terminal-side azimuth sensor <NUM>, terminal-side swivel manipulation tool <NUM>, terminal-side extension/retraction manipulation tool <NUM>, terminal-side main-drum manipulation tool <NUM>, terminal-side sub-drum manipulation tool <NUM>, terminal-side luffing manipulation tool <NUM>, terminal-side display apparatus <NUM>, terminal-side communication device <NUM>, and the like.

Terminal-side control apparatus <NUM> is connected to terminal-side azimuth sensor <NUM>, and is capable of obtaining an azimuth detected by terminal-side azimuth sensor <NUM>.

Terminal-side control apparatus <NUM> is connected to suspended-load movement manipulation tool <NUM>, terminal-side swivel manipulation tool <NUM>, terminal-side extension/retraction manipulation tool <NUM>, terminal-side main-drum manipulation tool <NUM>, terminal-side sub-drum manipulation tool <NUM>, and terminal-side luffing manipulation tool <NUM>, and is capable of obtaining a manipulation signal including the tilt direction and the tilt amount of the manipulation stick of each of the manipulation tools.

Terminal-side control apparatus <NUM> can generate target speed signal Vd of load W from the manipulation signal of the manipulation stick obtained from the sensor of each of terminal-side swivel manipulation tool <NUM>, terminal-side extension/retraction manipulation tool <NUM>, terminal-side main-drum manipulation tool <NUM>, terminal-side sub-drum manipulation tool <NUM>, and terminal-side luffing manipulation tool <NUM>.

Terminal-side control apparatus <NUM> is connected to terminal-side display apparatus <NUM>, and is capable of causing terminal-side display apparatus <NUM> to display image i1, image i2, and various information from crane apparatus <NUM>. Terminal-side control apparatus <NUM> is also capable of causing the terminal-side display apparatus to rotationally display the indication of the azimuth in association with the azimuth obtained from terminal-side azimuth sensor <NUM>. Terminal-side control apparatus <NUM> is connected to terminal-side communication device <NUM>, and is capable of transmitting and receiving various information to and from communication device <NUM> of crane apparatus <NUM> via terminal-side communication device <NUM>.

As illustrated in <FIG>, terminal-side control apparatus <NUM> (see <FIG>) sets an azimuth with reference to the upper direction of remote manipulation terminal <NUM> based on the azimuth obtained from terminal-side azimuth sensor <NUM> (see <FIG>). For example, when the upper direction of remote manipulation terminal <NUM> pointing in the north direction is rotated leftward by θ1 = <NUM>°, the upper direction of remote manipulation terminal <NUM> points to the northwest. Terminal-side control apparatus <NUM> sets the upward direction of remote manipulation terminal <NUM> as the northwest. In other words, remote manipulation terminal <NUM> is configured to generate target speed signal Vd for moving load W in the azimuth in which suspended-load movement manipulation tool <NUM> is manipulated to be tilted. At this time, terminal-side control apparatus <NUM> changes the indication of the azimuth with reference to the upward direction on terminal-side display apparatus <NUM> to "NW" indicating the northwest.

Based on the manipulation signal for the tilt direction and the tilt amount obtained from suspended-load movement manipulation tool <NUM> as illustrated in <FIG>, terminal-side control apparatus <NUM> (see <FIG>) computes, per unit time t, target speed signal Vd composed of the moving direction and the moving speed of load W. For example, when suspended-load movement manipulation tool <NUM> is manipulated to be tilted in a direction of tilting angle θ2 of <NUM>° that is shifted leftward with respect to the upper direction in a state where the upper direction of remote manipulation terminal <NUM> is set to the north direction, terminal-side control apparatus <NUM> computes target speed signal Vd for moving load W at a moving speed corresponding to the tilt amount in the direction that is shifted by θ2 = <NUM>° to the west from the north. Here, unit time t is any set computation cycle. Terminal-side control apparatus <NUM> computes target speed signal Vd per unit time t when suspended-load movement manipulation tool <NUM> is manipulated to be tilted. In the present embodiment, n-th unit time t in the computation cycle after suspended-load movement manipulation tool <NUM> is manipulated to be tilted is referred to as unit time t(n), and first unit time t after the n-th unit time is referred to as unit time t(n+<NUM>). That is, a function of time t is indicated as a function of computation cycle n in the following description.

Next, the control of crane apparatus <NUM> by remote manipulation terminal <NUM> will be described with reference to <FIG>.

As illustrated in <FIG>, when the upper direction of remote manipulation terminal <NUM> pointing to the north is rotated leftward by θ1 = <NUM>° (see <FIG>), the upper direction of remote manipulation terminal <NUM> is set to the northwest. When suspended-load movement manipulation tool <NUM> of remote manipulation terminal <NUM> is manipulated to be tilted by any tilt amount in a direction shifted leftward by tilting angle θ2 = <NUM>°from the upward direction, terminal-side control apparatus <NUM> obtains, from the sensor (not illustrated) of suspended-load movement manipulation tool <NUM>, a manipulation signal for the tilt direction and the tilt amount of the tilt to the west that is the direction shifted by tilting angle θ2 = <NUM>° from the northwest that is the upward direction. Further, terminal-side control apparatus <NUM> computes, from the obtained manipulation signal per unit time t, target speed signal Vd for moving load W to the west at a moving speed corresponding to the tilt amount. Remote manipulation terminal <NUM> transmits computed target speed signal Vd to control apparatus <NUM> of crane <NUM> per unit time t.

When crane <NUM> receives target speed signal Vd per unit time t from remote manipulation terminal <NUM>, control apparatus <NUM> computes target course signal Pd of load W based on the azimuth of the tip of boom <NUM> obtained by vehicle-side azimuth sensor <NUM>. Further, control apparatus <NUM> computes, from target course signal Pd, target position coordinate p(n+<NUM>) of load W that represents a target position of the load. Control apparatus <NUM> generates operation signals Md for swivel valve <NUM>, extension/retraction valve <NUM>, luffing valve <NUM>, main valve <NUM>, and sub valve <NUM> for moving load W to target position coordinate p(n+<NUM>). Crane <NUM> moves load W at a speed corresponding to the tilt amount and to the west that is the tilt direction of suspended-load movement manipulation tool <NUM>. At this time, crane <NUM> controls hydraulic swivel motor <NUM>, the hydraulic extension/retraction cylinder, hydraulic luffing cylinder <NUM>, the hydraulic main motor, and the like by operation signals Md.

Crane <NUM> configured as described above obtains target speed signal Vd based on the azimuth from remote manipulation terminal <NUM> per unit time t and determines target position coordinate p(n+<NUM>) of load W based on the azimuth, so that the operator does not lose recognition of the operating direction of crane apparatus <NUM> relative to the manipulation direction of suspended-load movement manipulation tool <NUM>. In other words, the manipulation direction of suspended-load movement manipulation tool <NUM> and the moving direction of load W are computed with reference to an azimuth in common. It is thus possible to prevent erroneous manipulation during remote manipulation of crane apparatus <NUM>, and to perform the remote manipulation of the working apparatus easily and simply.

Next, Embodiment <NUM> of a control process of control apparatus <NUM> of crane <NUM> for computing target course signal Pd of load W and target position coordinate q(n+<NUM>) of the tip of boom <NUM> for generation of operation signals Md will be described with reference to <FIG>. Control apparatus <NUM> includes target-course computation section 31a, boom-position computation section 31b, and operation-signal generation section 31c.

As illustrated in <FIG>, target-course computation section 31a is a part of control apparatus <NUM> and converts target speed signal Vd of load W into target course signal Pd of load W. Target-course computation section 31a can obtain target speed signal Vd of load W per unit time t from remote manipulation terminal <NUM> via communication device <NUM>, the target speed signal being composed of the moving direction and the moving speed of load W. Further, target-course computation section 31a is configured to convert, per unit time t, obtained target speed signal Vd into target course signal Pd that is the positional information of load W by applying low-pass filter Lp to the obtained target speed signal.

Low-pass filter Lp is for attenuating a frequency equal to or higher than a predetermined frequency. Target-course computation section 31a applies low-pass filter Lp to target course signal Pd to prevent an occurrence of a singular point (abrupt positional change) by differential operation. Although fourth order low-pass filter Lp is used in the present embodiment to deal with a fourth-order differentiation in computation of spring constant kf, it is possible to apply low-pass filter Lp of the order according to desired characteristics. The letters "a" and "b" in Equation <NUM> are factors. [<NUM>]
<MAT>.

As illustrated in <FIG>, an inverse dynamics model of crane <NUM> is defined. The inverse dynamics model is defined in the XYZ coordinate system in which origin O is the swivel center for crane <NUM>. The letter "q" indicates current position coordinate q(n), for example, and "p" indicates current position coordinate p(n) of load W, for example. The letter "lb" indicates extension/retraction length lb(n) of boom <NUM>, for example, "θx" indicates luffing angle θx(n), for example, and "θz" indicates swivel angle θz(n), for example. The letter "<NUM>" indicates let-out amount l(n) of the wire rope, for example, "f" indicates tension f of the wire rope, for example, and "e" indicates direction vector e(n) of the wire rope, for example.

As illustrated in <FIG> and <FIG>, boom-position computation section 31b is a part of control apparatus <NUM> and computes the position coordinate of the tip of the boom from the postural information of boom <NUM> and target course signal Pd of load W. Boom-position computation section 31b can obtain target course signal Pd from target-course computation section 31a. Boom-position computation section 31b obtains swivel angle θz(n) of swivel base <NUM> from swivel sensor <NUM>, extension/retraction length lb(n) from extension/retraction sensor <NUM>, luffing angle θx(n) from luffing sensor <NUM>, let-out amount l(n) of main wire rope <NUM> or sub wire rope <NUM> (hereinafter, simply referred to as "wire rope") from winding sensor <NUM>, and the current positional information of load W from swivel-base cameras 7b (see <FIG>).

Boom-position computation section 31b can compute current position coordinate p(n) of load W from the obtained current positional information of load W, and compute, from obtained swivel angle θz(n), extension/retraction length lb(n), and luffing angle θx(n), current position coordinate q(n) of the tip of boom <NUM> (i.e., the position at which the wire rope is let out) (hereinafter, simply referred to as "current position coordinate q(n) of boom <NUM>") that represents the current position of the boom tip. Further, boom-position computation section 31b can compute let-out amount l(n) of the wire rope from current position coordinate p(n) of load W and current position coordinate Q of boom <NUM>. Furthermore, from current position coordinate p(n) of load W and target position coordinate p(n+<NUM>) of load W that represents the target position of load W after the lapse of unit time t, boom-position computation section 31b can compute direction vector e(n+<NUM>) of the wire rope from which load W is suspended. Boom-position computation section 31b is configured to compute, from target position coordinate p(n+<NUM>) of load W and direction vector e(n+<NUM>) of the wire rope and using the inverse dynamics, target position coordinate q(n+<NUM>) of boom <NUM> that represents a target position of the boom tip after the lapse of unit time t.

Let-out amount l(n) of the wire rope is computed using following Equation <NUM>.

Let-out amount l(n) of the wire rope is defined by the distance between current position coordinate Q of boom <NUM> that represents the position of the tip of boom <NUM> and current position coordinate p(n) of load W that represents the position of load W. [<NUM>]
<MAT>.

Direction vector e(n) of the wire rope is computed using following Equation <NUM>.

Direction vector e(n) of the wire rope is the vector of tension f (see Equation <NUM>) of the wire rope for a unit length. Tension f of the wire rope is obtained by subtracting the gravitational acceleration from the acceleration of load W computed from current position coordinate p(n) of load W and target position coordinate p(n+<NUM>) of load W after the lapse of unit time t. [<NUM>]
<MAT>.

Target position coordinate q(n+<NUM>) of boom <NUM> that represents the target position of the boom tip after the lapse of unit time t is computed from following Equation <NUM> that is Equation <NUM> expressed as a function of n. Here, "α" indicates swivel angle θz(n) of boom <NUM>.

Target position coordinate q(n+<NUM>) of boom <NUM> is computed from let-out amount l(n) of the wire rope, target position coordinate p(n+<NUM>) of load W, and direction vector e(n+<NUM>) using the inverse dynamics. [<NUM>]
<MAT>.

Operation-signal generation section 31c is a part of control apparatus <NUM> and generates operation signal Md for each actuator from target position coordinate q(n+<NUM>) of boom <NUM> after the lapse of unit time t. Operation-signal generation section 31c can obtain, from boom-position computation section 31b, target position coordinate q(n+<NUM>) of boom <NUM> after the lapse of unit time t. Operation-signal generation section 31c is configured to generate operation signals Md for swivel valve <NUM>, extension/retraction valve <NUM>, luffing valve <NUM>, and main valve <NUM> or sub valve <NUM>.

As illustrated in <FIG>, at step S100, control apparatus <NUM> starts target-course computation process A in the method of controlling crane <NUM>, and the control proceeds to step S110 (see <FIG>). Then, when target-course computation process A is completed, the control proceeds to step S200 (see <FIG>).

At step <NUM>, control apparatus <NUM> starts boom-position computation process B in the method of controlling crane <NUM>, and the control proceeds to step S210 (see <FIG>). Then, when boom-position computation process B is completed, the control proceeds to step S300 (see <FIG>).

At step <NUM>, control apparatus <NUM> starts operation-signal generation process C in the method of controlling crane <NUM>, and the control proceeds to step S310 (see <FIG>). Then, when operation-signal generation process C is completed, the control proceeds to step S100 (see <FIG>).

As illustrated in <FIG>, at step S110, target-course computation section 31a of control apparatus <NUM> obtains target speed signal Vd of load W inputted in the form of a process function from remote manipulation terminal <NUM>, and the process proceeds to step S120.

At step S120, target-course computation section 31a computes the positional information of load W by integrating obtained target speed signals Vd of load W, and the process proceeds to step S130.

At step S130, target-course computation section 31a computes target course signal Pd per unit time t by applying low-pass filter Lp indicated by transfer function G(s) of Equation <NUM> to the computed positional information of load W, and ends target-course computation process A. The process then proceeds to step S200 (see <FIG>).

As illustrated in <FIG>, at step S210, boom-position computation section 31b of control apparatus <NUM> computes, from the obtained current positional information of load W, current position coordinate p(n) of load W that represents the current position of the load with respect to any determined reference position O (for example, the swivel center for boom <NUM>) serving as the origin, and the process proceeds to step S220.

At step S220, boom-position computation section 31b computes current position coordinate q(n) of boom <NUM> from obtained swivel angle θz(n) of swivel base <NUM>, extension/retraction length lb(n), and luffing angle θx(n) of boom <NUM>, and the process proceeds to step S230.

At step S230, boom-position computation section 31b computes let-out amount l(n) of the wire rope using above-described Equation <NUM> from current position coordinate p(n) of load W and current position coordinate q(n) of boom <NUM>, and the process proceeds to step S240.

At step S240, boom-position computation section 31b computes, from target course signal Pd and with reference to current position coordinate p(n) of load W, target position coordinate p(n+<NUM>) of load W that represents the target position of the load after the lapse of unit time t, and the process proceeds to step S250.

At step S250, boom-position computation section 31b computes the acceleration of load W from current position coordinate p(n) of load W and target position coordinate p(n+<NUM>) of load W, and computes direction vector e(n+<NUM>) of the wire rope by above-described Equation <NUM> using the gravitational acceleration, and the process proceeds to step S260.

At step S260, boom-position computation section 31b computes target position coordinate q(n+<NUM>) of boom <NUM> using above-described Equation <NUM> from computed let-out amount <NUM>(n) of the wire rope and direction vector e(n+<NUM>) of the wire rope, and ends boom-position computation process B. The control then proceeds to step S300 (see <FIG>).

As illustrated in <FIG>, at step S310, operation-signal generation section 31c of control apparatus <NUM> computes swivel angle θz(n+<NUM>) of swivel base <NUM>, extension/retraction length Lb(n+<NUM>), luffing angle θx(n+<NUM>), and let-out amount l(n+<NUM>) of the wire rope after the lapse of unit time t from target position coordinate q(n+<NUM>) of boom <NUM>, and the process proceeds to step S320.

At step S320, operation-signal generation section 31c generates operation signals Md respectively for swivel valve <NUM>, extension/retraction valve <NUM>, luffing valve <NUM>, and main valve <NUM> or sub valve <NUM> from computed swivel angle θz(n+<NUM>) of swivel base <NUM>, extension/retraction length Lb(n+<NUM>), luffing angle θx(n+<NUM>), and let-out amount l(n+<NUM>) of the wire rope, and ends operation-signal generation process C. The control then proceeds to step S100 (see <FIG>).

Control apparatus <NUM> repeats target-course computation process A, boom-position computation process B, and operation-signal generation process C to compute target position coordinate q(n+<NUM>) of boom <NUM>, compute direction vector e(n+<NUM>) of the wire rope from let-out amount l(n+<NUM>) of the wire rope, current position coordinate p(n+<NUM>) of load W, and target position coordinate p(n+<NUM>) of load W after the lapse of unit time t, and compute target position coordinate q(n+<NUM>) of boom <NUM> after the lapse of another unit time t from let-out amount l(n+<NUM>) of the wire rope and direction vector e(n+<NUM>) of the wire rope. In other words, control apparatus <NUM> computes direction vector e(n) of the wire rope, and then successively computes target position coordinate q(n+<NUM>) of boom <NUM> after unit time t from current position coordinate p(n+<NUM>) of load W, target position coordinate p(n+<NUM>) of load W, and direction vector e(n) of the wire rope using the inverse dynamics. Control apparatus <NUM> controls the actuators by feedforward control for generating operation signals Md based on target position coordinate q(n+<NUM>) of boom <NUM>.

Crane <NUM> configured as described above computes target course signal Pd based on any target speed signal Vd of load W inputted from remote manipulation terminal <NUM>, so that the speed pattern of the crane is not limited to a prescribed speed pattern. In addition, crane <NUM> generates the control signal for boom <NUM> with reference to load W, and the feedforward control for generating the control signal for boom <NUM> based on the target course intended by the operator is applied in the crane. Thus, in crane <NUM>, a response delay in response to a manipulation signal is small so that a swing of load W due to the response delay is prevented. Further, the inverse dynamics model is constructed, and target position coordinate q(n+<NUM>) of boom <NUM> is computed from direction vector e(n) of the wire rope, current position coordinate p(n+<NUM>) of load W, and target position coordinate p(n+<NUM>) of load W, so that there is no error that could be caused in the transitional state during acceleration, deceleration, or the like. Furthermore, since the frequency component including the singular point caused by the differential operation for computation of target position coordinate q(n+<NUM>) of boom <NUM> is attenuated, the control of boom <NUM> is stabilized. It is thus possible to move load W along the target course while reducing the swing of load W, when controlling the actuators with reference to load W.

Next, Embodiment <NUM> of the control process of control apparatus <NUM> of crane <NUM> for computing target course signal Pd of load W and target position coordinate q(n+<NUM>) of the tip of boom <NUM> for generation of operation signals Md will be described with reference to <FIG>. In Embodiment <NUM>, control apparatus <NUM> computes target position coordinate q(n+<NUM>) of boom <NUM> using spring constant kf of the wire rope. Note that, the control process according to the below-described embodiment is applied to the control process illustrated in <FIG> instead of a vibration control for an unused hook, and the same components are provided with the same names, reference numerals, and symbols between the control process illustrated in <FIG> and the control process according to the below-described embodiment. In the following embodiment, the detailed descriptions of the same points as in the already described embodiment will be omitted, and differences between the embodiments will be mainly described.

As illustrated in <FIG>, control apparatus <NUM> includes target-course computation section 31a, boom-position computation section 31b, and operation-signal generation section 31c.

As illustrated in <FIG> and <FIG>, boom-position computation section 31b is a part of control apparatus <NUM> and computes the position coordinate of the tip of the boom from the postural information of boom <NUM> and target course signal Pd of load W. Boom-position computation section 31b can obtain target course signal Pd from target-course computation section 31a. Boom-position computation section 31b obtains swivel angle θz(n) of swivel base <NUM> from swivel sensor <NUM>, extension/retraction length lb(n) from extension/retraction sensor <NUM>, luffing angle θx(n) from luffing sensor <NUM>, let-out amount l(n) of main wire rope <NUM> or sub wire rope <NUM> (hereinafter, simply referred to as "wire rope") from winding sensor <NUM>, and the current positional information of load W from swivel-base cameras 7b (see <FIG>). Boom-position computation section 31b is configured to compute, using the inverse dynamics, target position coordinate q(n+<NUM>) of boom <NUM> that represents the target position of the boom tip after the lapse of unit time t from target position coordinate p(n+<NUM>) of load W that represents the target position of the load after the lapse of unit time t based on target course signal Pd and from spring constant kf of the wire rope from which load W is suspended.

Spring constant kf of the wire rope is computed using following Equation <NUM>, and target position coordinate q(n+<NUM>) of boom <NUM> is computed using following Equation <NUM>.

A force by gravitational acceleration and a force from crane <NUM> are exerted on moving load W. When the characteristics of the wire rope are expressed by spring constant kf, the equation of motion expressed by following Equation <NUM> holds for load W. [<NUM>]
<MAT>.

Let-out amount <NUM> of the wire rope can be expressed by following Equation <NUM>. By second-order differentiation of let-out amount <NUM> of the wire rope, following Equation <NUM> is obtained. In Equations <NUM> and <NUM>, "p" denotes the position coordinate of load W, "q" denotes the position coordinate of boom <NUM>, and "l" denotes the let-out amount of the wire rope. [<NUM>]
<MAT> [<NUM>]
<MAT>.

Multiplication of Equation <NUM> expressing the equation of motion of load W by (q-p)T gives following Equation <NUM>. Following Equation <NUM> expressing spring constant kf is obtained from Equation <NUM>. In Equation <NUM>, "g" denotes the gravitational acceleration, "m" denotes the mass of load W, and "kf' denotes the spring constant of the wire rope. [<NUM>]<MAT>
[<NUM>]<MAT>.

As illustrated in <FIG>, at step S211, boom-position computation section 31b of control apparatus <NUM> computes, from the obtained current positional information of load W, current position coordinate p(n) of load W that represents the current position of the load with respect to any determined reference position O serving as the origin, and the process proceeds to step S221.

At step S221, boom-position computation section 31b computes, from obtained swivel angle θz(n) of swivel base <NUM>, extension/retraction length lb(n), luffing angle θx(n) of boom <NUM>, and let-out amount l(n) of the wire rope, current position coordinate q(n) of the tip of boom <NUM> (i.e., the position at which the wire rope is let out) (hereinafter, simply referred to as "current position coordinate q(n) of boom <NUM>") that represents the current position of the boom tip, and the process proceeds to step S231.

At step S231, boom-position computation section 31b computes spring constant kf of the wire rope using above-described Equation <NUM> from current position coordinate p(n) of load W, current position coordinate q(n) of boom <NUM>, let-out amount l(n) of the wire rope, and mass m of load W, and the process proceeds to step S241.

At step S241, boom-position computation section 31b computes, from target course signal Pd and with reference to current position coordinate p(n) of load W, target position coordinate p(n+<NUM>) of load W that represents the target position of the load after the lapse of unit time t, and the process proceeds to step S251.

At step S251, boom-position computation section 31b computes, from target position coordinate p(n+<NUM>) of load W and spring constant kf and using Equation <NUM>, target position coordinate q(n+<NUM>) of boom <NUM> that represents the target position of the boom tip after the lapse of unit time t, and ends boom-position computation process B. The process then proceeds to step S300 (see <FIG>).

Control apparatus <NUM> repeats target-course computation process A, boom-position computation process B, and operation-signal generation process C to compute target position coordinate q(n+<NUM>) of boom <NUM>, compute spring constant kf from let-out amount l(n+<NUM>) of the wire rope, current position coordinate p(n+<NUM>) of load W, and current position coordinate q(n+<NUM>) of boom <NUM> after the lapse of unit time t, and compute target position coordinate q(n+<NUM>) of boom <NUM> after the lapse of another unit time t from spring constant kf and target position coordinate p(n+<NUM>) of load W after the lapse of another unit time t. In other words, the characteristics of the wire rope are expressed as spring constant kf, and control apparatus <NUM> successively computes, using the inverse dynamics, target position coordinate q(n+<NUM>) of boom <NUM> after the lapse of unit time t from target position coordinate p(n+<NUM>) of load W and current position coordinate q(n) of boom <NUM>. Control apparatus <NUM> controls the actuators by feedforward control for generating operation signals Md based on target position coordinate q(n+<NUM>) of boom <NUM>.

Crane <NUM> configured as described above computes target course signal Pd based on any target speed signal Vd of load W inputted from remote manipulation terminal <NUM>, so that the speed pattern of the crane is not limited to a prescribed speed pattern. In addition, crane <NUM> generates the control signal for boom <NUM> with reference to load W, and the feedforward control for generating the control signal for boom <NUM> based on the target course intended by the operator is applied in the crane. Thus, in crane <NUM>, a response delay in response to a manipulation signal is small so that a swing of load W due to the response delay is prevented. Further, the inverse dynamics model considering the characteristics of the wire rope is constructed, and target position coordinate q(n+<NUM>) of boom <NUM> is computed from spring constant kf of the wire rope and target position coordinate p(n+<NUM>) of load W, so that there is no error that could be caused in the transitional state during acceleration, deceleration, or the like. Furthermore, since the frequency component including the singular point caused by the differential operation for computation of target position coordinate q(n+<NUM>) of boom <NUM> is attenuated, the control of boom <NUM> is stabilized. It is thus possible to move load W along the target course while reducing the swing of load W, when controlling the actuators with reference to load W.

Claim 1:
A crane (<NUM>) that controls an actuator of a boom (<NUM>) based on a target speed signal related to a moving direction and a speed of a load (W) suspended from the boom (<NUM>) by a wire rope (<NUM>,<NUM>), the crane (<NUM>) comprising:
a swivel angle detection means (<NUM>) of the boom (<NUM>);
a luffing angle detection means (<NUM>) of the boom (<NUM>);
an extension/retraction length detection means (<NUM>) of the boom (<NUM>);
a load position detection means (7b,9b) that detects a current position of the load (W) relative to a reference position; and
a control apparatus (<NUM>), wherein
the control apparatus (<NUM>)
converts the target speed signal into a target position of the load (W) relative to the reference position,
computes a current position of a boom tip (<NUM>) relative to the reference position from a swivel angle detected by the swivel angle detection means (<NUM>), a luffing angle detected by the luffing angle detection means (<NUM>), and an extension/retraction length detected by the extension/retraction length detection means (<NUM>),
computes a let-out amount of the wire rope (<NUM>,<NUM>) from the current position of the load detected by the load position detection means (7b,9b) and the current position of the boom tip (<NUM>),
computes, from the current position of the load (W) and the target position of the load (W), a direction vector of the wire rope (<NUM>,<NUM>),
computes a target position of the boom tip (<NUM>) for the target position of the load (W) from the let-out amount of the wire rope (<NUM>,<NUM>) and the direction vector of the wire rope (<NUM>,<NUM>), and
generates an operation signal for the actuator based on the target position of the boom tip (<NUM>).