Crane and crane control method

Patent metadata

Field	Value
Publication number	US-11718510-B2
Application number	US-201916978420-A
Country	US
Kind code	B2
Filing date	Mar 13, 2019
Priority date	Mar 15, 2018
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

The invention addresses the problem of providing a crane and a crane control method that can suppress load swaying when controlling an actuator on the basis of the load. The invention is provided with a turntable camera (7b) that detects the current position coordinates p(n) of a load W with respect to a reference position, wherein the invention: converts a target speed signal Vd to target position coordinates p(n+1) of the load W with respect to the reference position; calculates the current position coordinates q(n) of a boom (9) with respect to the reference position from a turning angle θz(n), a hoisting angle θx(n), and an extension/contraction length lb(n); calculates a feed amount l of the wire rope and the directional vector e(n) of the wire rope from the current position coordinates p(n) of the load W and the current position coordinates (n) of the boom (9); calculates the target position coordinates q(n+1) of the boom (9) with regards to the target position coordinates (n+1) of the load W from the feed amount l and the directional vector e(n) of the wire rope; and generates an actuator operation signal Md on the basis of the target position coordinates q(n+1) of the boom (9).

First claim

The invention claimed is:

1. A crane configured to control 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 comprising:
a swivel sensor configured to detect a swivel angle of the boom;
a luffing sensor configured to detect a luffing angle of the boom;
an extension/retraction sensor configured to detect an extension/retraction length of the boom;
a load position sensor configured to detect a current position of the load relative to a reference position; and
a processor configured to:
convert the target speed signal into a target position of the load relative to the reference position,
compute a current position of a boom tip relative to the reference position from a swivel angle detected by the swivel sensor, a luffing angle detected by the luffing sensor, and an extension/retraction length detected by the extension/retraction sensor,
compute a let-out amount of the wire rope from the current position of the load detected by the load position sensor and the current position of the boom tip,
compute, from the current position of the load and the target position of the load, a direction vector of the wire rope at a timing at which the load reaches the target position,
compute a target position of the boom tip for the target position of the load from the let-out amount of the wire rope and the direction vector of the wire rope, and
generate an operation signal for the actuator based on the target position of the boom tip.

2. The crane according to claim 1 , wherein
the processor is further configured to convert the target speed signal into the target position of the load by integrating the target speed signal and attenuating a frequency component in a predetermined frequency range.

3. The crane according to claim 2 , wherein
a relationship between the target position of the boom tip and the target position of the load is expressed by the following Equation 1 based on the target position of the load, a weight of the load, and a spring constant of the wire rope, and
the processor is further configured to compute the target position of the boom tip by the following Equation 2 that is a function of time for the load:
[1]
m{umlaut over (p)}g=mg+f=mg+k f ( q−p )  (Equation 1)

[2]
q ( t )= p ( t )+ l ( t ,α) e ( t )= q ( p ( t ), {umlaut over (p)} ( t ),α)  (Equation 2)

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, “l” denotes the let-out amount of the wire rope, “α” denotes the swivel angle, and “g” denotes gravitational acceleration.

4. The crane according to claim 1 , further comprising:
a remote manipulation apparatus configured to receive manipulation by an operator and generate the target speed signal according to content of the manipulation.

5. A method of controlling a crane comprising a processor and configured to control 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 method performed by the processor and comprising:
converting the target speed signal into a target position of the load;
computing a let-out amount of the wire rope from a current position of the load and a current position of a boom tip relative to a reference position;
computing a direction vector of the wire rope from the current position of the load and the target position of the load;
computing a target position of the boom tip for the target position of the load from the let-out amount and the direction vector of the wire rope; and
generating an operation signal for the actuator based on the target position of the boom tip.

Assignees

• Tadano Ltd

Inventors

• Minami Yoshimasa

Classifications

• B66C13/48 Primary

  Automatic control of crane drives for producing a single or repeated working cycle; Program control · CPC title

• B66C13/085

  electrical · CPC title

• B66C13/46 Primary

  Position indicators for suspended loads or for crane elements · CPC title

• B66C23/36

  mounted on road or rail vehicles; Manually-movable jib-cranes for use in workshops; Floating cranes (with pneumatic or hydraulic motors B66C23/54; vehicle or ship aspects B60 - B63) · CPC title

• B66C2700/0371

  on a turntable · CPC title