US-12625153-B2 - Conveyance device

US12625153B2US 12625153 B2US12625153 B2US 12625153B2US-12625153-B2

Abstract

Provided is a conveyance device that conveys a conveyance object having a magnetic body, the conveyance device including: a plurality of coils configured to generate magnetic flux acting on the magnetic body; a coil driving unit configured to apply a voltage to each of the plurality of coils; and a calculation control unit including a current control unit and a position estimation unit. The current control unit determines the voltage. The position estimation unit estimates a position of the conveyance object based on a change in a current generated by applying a voltage pulse to the coils and switches, according to a position estimation value that indicates the position of the conveyance object estimated by the position estimation unit, between a speed control mode in which a speed of the conveyance object is controlled and a current control mode in which a current through the coils is controlled. Accordingly, in the conveyance device that has a function of estimating the position of the conveyance object based on information on the current flowing through winding wires of the coils, it is possible to implement stable conveyance speed control even in a section in which accuracy for estimating the position or speed of the conveyance object is low.

Inventors

Satoru Kaneko
Takahiro Suzuki
Yasuaki Aoyama
Ryosuke HOSHI
Shinji Azuma
Takeshi TAMAKOSHI

Assignees

HITACHI HIGH-TECH CORPORATION

Dates

Publication Date: 20260512
Application Date: 20220913
Priority Date: 20211109

Claims (4)

1 . A conveyance device that conveys a conveyance object including a magnetic body, the conveyance device comprising: a plurality of coils configured to generate magnetic flux acting on the magnetic body; a coil driving unit configured to apply a voltage to each of the plurality of coils; and a calculation control unit including a current control unit and a position estimation unit, wherein the current control unit determines the voltage, the position estimation unit estimates a position of the conveyance object based on a change in a current generated by applying a voltage pulse to the coils, and switches, according to a position estimation value that indicates the position of the conveyance object estimated by the position estimation unit, between a speed control mode in which a speed of the conveyance object is controlled and a current control mode in which a current through the coils is controlled.
2 . The conveyance device according to claim 1 , wherein in the current control mode, a current command is generated based on a magnitude of a current flowing through an energized coil at a last time.
3 . The conveyance device according to claim 1 , wherein the position estimation value is calculated based on a current change rate of a predetermined coil among the plurality of coils.
4 . The conveyance device according to claim 1 , wherein the calculation control unit further includes a control mode determination unit and a control mode switching unit, and the control mode determination unit receives information on a coil being energized among the plurality of coils and the position estimation value, determines the switching based on accuracy of a calculation value of the speed of the conveyance object, and transmits a result of the determination to the control mode switching unit.

Description

TECHNICAL FIELD The present disclosure relates to a conveyance device. BACKGROUND ART With the advancement of medical care and aging of society, the importance of specimen processing in a clinical test is increasing. A specimen processing device used in a clinical test tests a predetermined analysis item on a biological sample (a specimen) of a body fluid or the like such as blood, plasma, serum, and urine. The specimen processing device can connect devices having a plurality of functions and automatically process each step. In other words, in order to rationalize work in an inspection room, analysis units in a plurality of analysis fields such as biochemistry and immunity are connected by a conveyance line and are operated as one device. A conveyance line in the related art is mainly of a belt drive type. Therefore, when conveyance is stopped due to an abnormality occurring in the middle of the conveyance, a specimen cannot be supplied to a downstream device. In order to improve a processing capacity of a specimen processing device, it is desired to convey specimens at high speed, convey a large number of specimens at the same time, and convey specimens in a plurality of directions. PTL 1 discloses an electromagnetic actuator that is a container carrier including a magnetic active device such as a permanent magnet, that is disposed to be stationary below a conveyance plane adapted to carry a container adapted to carry a sample container, and that is adapted to move the container carrier on the conveyance plane by applying a magnetic force to the container carrier. Further, PTL 1 discloses that a speed of the container carrier that is moved on the conveyance plane is set by setting a time between contiguous activation of adjacent electromagnetic actuators. Further, PTL 1 discloses that a container carrier detection device embodied based on a reflected light barrier mainly including an infrared ray (IR) is provided in order to detect a presence and position of the container carrier positioned on the conveyance plane. PTL 2 discloses a configuration in which each of a plurality of electromagnetic actuators used in a laboratory sample distribution system includes a ferromagnetic core and an excitation winding wire, and the excitation winding wire exceeds the assigned ferromagnetic core in a vertical direction. In addition, PTL 2 discloses that the plurality of electromagnetic actuators are disposed below a transfer surface of the laboratory sample distribution system, and a plurality of position sensors embodied as Hall sensors are distributed on the transfer surface. Further, PTL 3 discloses a conveyance device including a first magnetic body provided on a conveyance body side, a magnetic circuit including a core made of a second magnetic body and a winding wire wound around an outer peripheral side of the core, a driving circuit for supplying a current to the winding wire of the magnetic circuit, and a conveyance body detection unit for detecting a position or a speed of the magnetic body. The current supplied to the winding wire is changed based on the position or the speed information of the magnetic body detected by the conveyance body detection unit. PTL 4 discloses a conveyance device in which a coil driving unit that applies a voltage to each of a plurality of coils applies a driving current to a predetermined coil based on a position of a conveyance object estimated by a position estimation unit and path information stored in a path information storage unit, and applies a current for position detection to a closest coil estimated to be closest to the conveyance object and coils around the closest coil. Further, PTL 4 discloses that a current change amount for each position is calculated based on an inductance characteristic, a position of a permanent magnet is estimated at any time by sequentially calculating the current change amount, it is determined whether a conveyance object deviates from a predetermined path, and a pulse voltage is output to the predetermined coil so as to return to the predetermined path. CITATION LIST Patent Literature PTL 1: JP2017-77971APTL 2: JP2017-102103APTL 3: JP2020-142913APTL 4: JP2020-125930A SUMMARY OF INVENTION Technical Problem A large number of sensors (position sensors) for detecting the positions of the container carrier detection device in PTL 1 and the Hall sensors in PTL 2 are required, and there is a concern that a cost is increased and reliability is lowered due to a failure of the position sensor. Further, in PTLS 1 and 2, since the presence or absence of the conveyance object cannot be detected unless the conveyance object approaches the position sensor to some extent, it is considered that it is difficult to detect the conveyance object in all regions on the conveyance surface. In PTL 3, the current flowing through the winding wire is changed according to the position, weight, and the like of the conveyance object, but a method of determining a value of