Conveyor

Abstract

To suppress liquid wavering corresponding to the switching of an energized coil in a carrier apparatus.SOLUTION: A carrier apparatus for carrying a to-be-carried article with a magnetic material comprises: a plurality of coils for generating a thrust for carrying the to-be-carried article; a coil drive unit for applying a pulsed voltage to each of the plurality of coils; and an arithmetic unit. The arithmetic unit determines a width of the pulsed voltage so that a speed or an acceleration speed of the to-be carried article is stabilized based on a position, and a time of passing the position, of the to-be-carried article during a prescribed period before the switching of the energizing, or current that flows through the energized coil when switching the energized coil, to be output to the coil drive unit.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a transport device. [Background technology]

[0002] With the advancement of medical technology and the progress of an aging society, specimen processing in clinical testing is becoming increasingly important.

[0003] Sample processing equipment used in clinical testing tests specific analytical items on biological samples (specimens), such as bodily fluids like blood, plasma, serum, and urine. Sample processing equipment can be connected to devices with multiple functions and automatically process each step. In other words, to streamline laboratory operations, analysis sections for multiple analytical fields, such as biochemistry and immunology, are connected by a transport line and operated as a single device.

[0004] Conventional transport lines are mainly belt-driven, so if an abnormality occurs and the transport stops midway, the specimen cannot be supplied to the downstream device.

[0005] In order to improve the processing capacity of a sample processing apparatus, high-speed transport of samples, simultaneous transport of a large number of samples, and transport in multiple directions are desired.

[0006] Patent Document 1 discloses an electromagnetic actuator stationarily disposed below a transport plane adapted to carry a container carrier equipped with a magnetically activated device such as a permanent magnet, the container carrier adapted to carry a sample container, and adapted to move the container carrier on the transport plane by applying a magnetic force to the container carrier. Patent Document 1 also discloses that the speed of the container carrier moving on the transport plane is set by setting the time between successive activations of adjacent electromagnetic actuators.

[0007] Patent Document 2 discloses a conveying device having a conveying plane above which a conveying container having a magnetic body is conveyed, a position detection unit that detects the position of the conveying container on the conveying plane, a magnetic pole arranged below the conveying plane and having a core and a coil, a drive unit that applies a voltage to the magnetic pole, and a calculation unit that controls the drive unit, wherein the drive unit detects a current flowing through the magnetic pole, the calculation unit detects the position of the conveying container on the conveying plane based on the detected current, calculates the conveying speed of the conveying container based on the position of the conveying container on the conveying plane and the time when the conveying container passes the position, and detects the surface condition of the conveying plane based on the calculated conveying speed of the conveying container. Patent Document 2 also describes that when a permanent magnet is moved by a voltage pulse, the effective current value, instantaneous current value, duty of the voltage pulse, etc. may be used, and describes the magnitude and pulse width of the voltage pulse as a voltage waveform applied to the coil to detect the position of the conveying container. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-77971 [Patent Document 2] Patent Publication No. 2021-10254 Summary of the Invention [Problem to be solved by the invention]

[0009] The electromagnetic actuator described in Patent Document 1 adjusts the speed of the container carrier by adjusting the time between successive activations of the electromagnetic actuator.

[0010] The conveying device described in Patent Document 2 may use a voltage pulse duty or the like when moving the permanent magnet.

[0011] Generally, in a conveying device, coils are arranged discretely, so when the coils to be energized are switched, thrust pulsation occurs, which causes the liquid to sway. This phenomenon is difficult to avoid structurally.

[0012] Patent Documents 1 and 2 do not describe any measures to suppress the liquid shaking, and it is believed that there is room for improvement.

[0013] An object of the present disclosure is to suppress liquid swaying that occurs when a coil to which electricity is applied is switched in a conveying device. [Means for solving the problem]

[0014] The conveying device disclosed herein is for conveying a magnetic object, and includes a plurality of coils that generate thrust for conveying the object, a coil driving unit that applies a pulsed voltage to each of the plurality of coils, and a calculation unit.When switching the coil to be energized, the calculation unit determines the width of the pulsed voltage so as to stabilize the speed or acceleration of the object based on the position of the object during a predetermined period prior to the energization switch and the time at which it passed that position, or the current flowing through the energized coil, and outputs the determined width to the coil driving unit. [Effects of the Invention]

[0015] According to the present disclosure, it is possible to suppress liquid swaying that occurs when the coil to which current is applied is switched in the conveying device. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic configuration diagram showing a conveying device according to a first embodiment. [Figure 2] 10 is a graph showing the thrust force acting on the permanent magnet relative to the distance between the coil and the permanent magnet. [Figure 3] 1 is a functional block diagram showing a configuration of a conveyance device according to a first embodiment. [Figure 4] 10 is a graph showing an example of position characteristics of inductance of a coil. [Figure 5] 10 is a graph showing an example of position characteristics of the time rate of change of current flowing through a coil. [Figure 6] 4 is a configuration diagram illustrating an example of a current-carrying coil switching determiner in FIG. 3. FIG. [Figure 7] 10 is a graph showing the position of a coil that applies a thrust when energized to a sample folder being transported, and the velocity of the sample folder. [Figure 8] FIG. 4 is a configuration diagram illustrating an example of an initial voltage command generator in FIG. 3. [Figure 9] 10 is a graph showing the change over time in the speed of a transported sample folder. [Figure 10] 4 is a configuration diagram showing another example of the initial voltage command generator of FIG. 3. FIG. [Figure 11] 4 is a configuration diagram showing another example of the initial voltage command generator of FIG. 3. FIG. [Figure 12] FIG. 4 is a configuration diagram illustrating an example of a voltage command generator in FIG. 3. [Figure 13] FIG. 10 is a functional block diagram showing the configuration of a conveyance device according to a second embodiment. [Figure 14] 10 is a graph showing an example of the velocity of the specimen holder and the output voltage in the acceleration region. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present disclosure relates to a transport device suitable for a sample analysis system that analyzes biological samples (hereinafter referred to as "samples") such as blood and urine, and a sample pretreatment device that performs pretreatment required for analysis.

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, in which like reference numerals denote like elements and the same description will not be repeated.

[0019] The various components of the present disclosure do not necessarily have to be independent entities, and it is acceptable for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, or for part of one component to overlap with part of another component, etc. [Example]

[0020] <Overview of the transport device> FIG. 1 is a schematic diagram showing the configuration of a conveying device according to a first embodiment.

[0021] In this figure, the transport device 100 includes a permanent magnet 10, two coils 25, a coil drive unit 50 (drive circuit), a power supply 55, a current detection unit 30, and a calculation unit 40. The permanent magnet 10 is provided on a sample folder or the like, which is an object to be transported. The coil 25 is composed of a cylindrical core 22 and a winding 21 provided on the outer periphery of the core 22. Although two coils 25 are shown in this figure, typically two or more coils 25 are provided.

[0022] The coil driving units 50 are connected to the respective coils 25. The current detecting units 30 detect the currents flowing from the respective coil driving units 50 to the windings 21 of the respective coils 25.

[0023] The permanent magnet 10 generates a propulsive force due to interaction with the coil 25. The transported object, such as a sample folder to which the permanent magnet 10 is attached, moves due to this propulsive force. As a result, the sample container or the like (not shown) placed in the sample folder is transported. The speed, direction of movement, and destination of the transported object are adjusted by controlling the current flowing through the coil 25.

[0024] Typically, a transport surface (not shown) that supports the permanent magnet 10 is provided between the coil 25 and the permanent magnet 10. The coils 25 may be configured such that a plurality of coils 25 are arranged in a row below the transport surface. In this case, the transport surface may move the transported object along a linear or curved path. Furthermore, when the transport surface is defined as an xy plane, the coils 25 may be configured such that a plurality of coils 25 are arranged in rows in each of the x-axis and y-axis directions below the xy plane. The permanent magnet 10 moves in a sliding manner on the transport surface. Note that the transported container is not limited to a specimen container, but may also be a reagent container or the like. Therefore, the transported container may also be called a "transport container." In addition, the transported object may include small transportable devices.

[0025] The conveying device 100 moves the object between the coils 25 by passing a current through the windings 21 and applying an electromagnetic force to the permanent magnets 10. In order to efficiently apply the electromagnetic force and move the object in a desired direction, relative position information between the permanent magnets 10 and the coils 25 is required.

[0026] For example, if the permanent magnet 10 is located directly above one of the two coils 25, passing a current through the coil 25 directly below it will not generate a force in the transport direction. In contrast, if a current is passed through the coil 25 adjacent to the coil 25 directly above the permanent magnet 10, a force can be generated that attracts the permanent magnet 10 to the adjacent coil 25. In other words, it is possible to efficiently generate force and control the direction of that force.

[0027] By arranging three or more coils 25 in a line and sequentially switching the coils 25 to be energized (energized coils), it becomes possible to move the transported object having the permanent magnet 10 arbitrarily.

[0028] In the above description, the permanent magnet 10 is used, but other magnets or soft magnetic materials may be used instead of the permanent magnet 10. Also, instead of the permanent magnet 10, a combination of the permanent magnet 10 and a soft magnetic material may be attached.

[0029] <Thrust characteristics> 2 is a graph showing the thrust acting on the permanent magnet versus the distance between coil 25 and permanent magnet 10. The horizontal axis represents the distance from coil 25 (excitation coil) of permanent magnet 10, and the vertical axis represents the thrust acting on the permanent magnet. The dotted line represents the case where no current flows through coil 25, the dashed-dotted line represents the case where the current is relatively small, and the solid line represents the case where the current is relatively large.

[0030] As mentioned above, in the configuration shown in Fig. 1, a conveying surface (not shown) is provided between the coil 25 and the permanent magnet 10. Therefore, when a current is passed through the coil 25, forces are generated in the vertical and horizontal directions. Fig. 2 shows the force acting in the horizontal direction, i.e., the force that moves the permanent magnet on the conveying surface. Naturally, frictional force is generated when the permanent magnet moves on the conveying surface, and this force must also be taken into consideration, but this is omitted here for simplicity of explanation.

[0031] The thrust characteristics shown in FIG. 2 vary depending on the shape (diameter and length) of the cylindrical core 22, the shape (diameter and thickness) of the permanent magnet 10, the characteristics of the magnetic circuit such as the specifications of the winding 21 (linearity and number of turns), the current flowing through the winding 21, etc., but in this specification, the thrust characteristics will be described as being detectable.

[0032] As can be seen from Figure 2, when a constant current is applied, the thrust force acting on the permanent magnet 10 is position-dependent. In other words, speed fluctuations occur when transporting a sample container (transported object) having the permanent magnet 10. When speed fluctuations occur, the liquid in the sample container may shake, causing the sample to spill or become agitated.

[0033] Furthermore, when the coil 25 to be energized is switched, the distance between the permanent magnet 10 and the coil 25 changes suddenly. For example, when the coils 25 are arranged in a grid pattern with equal intervals of 20 mm and the linearly arranged coils are energized in sequence, the sample container having the permanent magnet 10 moves along the linear transport path on which the coils 25 are arranged. When the relative distance from the coil 25 becomes 5 mm, if the adjacent coil 25 arranged in the direction of movement of the sample container is excited, the distance from the coil 25 becomes 25 mm. Therefore, when the same current value is controlled to flow through the coils 25, that is, when the same voltage value is applied to the coils 25, the thrust force acting on the sample container having the permanent magnet 10 changes significantly.

[0034] <Overall configuration of the calculation unit> FIG. 3 is a functional block diagram illustrating the configuration of the conveying device of the first embodiment.

[0035] In this figure, the calculation unit 40 of the transport device 100 includes a voltage command generator 111, a specimen position estimator 112 (position estimator), a current-carrying coil switching determiner 113, and an initial voltage command generator 114.

[0036] The calculation unit 40 estimates the position of the specimen and determines whether to switch the energized coil based on the current flowing through the coil 25, and outputs a voltage command value to the coil driving unit 50. The coil driving unit 50 applies a voltage to the energized coil 25 in accordance with the command from the calculation unit 40.

[0037] Each block will be described below.

[0038] <Coil drive unit> The coil driver 50 is configured, for example, by a voltage-type inverter driven by a general PWM signal. The current detector 30 is configured by a shunt resistor, a current transformer (CT), etc. Here, PWM is an abbreviation for Pulse Width Modulation.

[0039] The voltage command value generated by the voltage command generator 111, which will be explained later, is compared with a triangular or sawtooth carrier wave, and the on / off time ratio (duty) of the inverter's switching element is controlled to control the voltage applied to the coil. Here, duty refers to the on time of the switching element. For example, a duty of 70% means that the switching element is on for 70% of one cycle of the carrier wave. In other words, as the duty increases, the output voltage pulse width becomes wider. This is equivalent to an increase in the output voltage.

[0040] The coil driver 50 may be, for example, a general full-bridge circuit (H-bridge circuit) made up of four switching elements. The coil driver 50 may be configured either to include a plurality of full-bridge circuits, the same number as the number of coils 25, or to have a configuration in which the number of full-bridge circuits is less than the number of coils 25 and the connections between the coils and the full-bridge circuits are switched as appropriate. The coils to be energized are switched in accordance with a signal from a higher-level controller (not shown) or a trigger signal from an energized coil switching determiner 113 (described later).

[0041] 2, the electromagnetic force (thrust) acting on the permanent magnet 10 depends on the current flowing through the coil 25, and therefore, in order to control the thrust, it is necessary to control the current. In this embodiment, the coil driver 50 is configured as a voltage-type full-bridge circuit, and therefore, the current flowing through the coil 25 is controlled by adjusting the output voltage of the coil driver 50, and as a result, the thrust is controlled.

[0042] <Necessity of location information> As described above, in the conveying device 100, an electromagnetic force is generated in the permanent magnet 10 by passing a current through the winding 21, causing the permanent magnet 10 to move on the conveying surface. In order to efficiently apply the electromagnetic force (thrust) to the permanent magnet 10 to move it in a desired direction or smoothly at a predetermined speed, relative position information between the permanent magnet 10 and the coil 25 is required.

[0043] As can be seen from the thrust characteristics in Figure 2, when permanent magnet 10 is directly above coil 25, that is, when the distance between permanent magnet 10 and coil 25 (excitation coil) in Figure 2 is zero, even if current is passed through coil 25, no force is generated to move permanent magnet 10 on the conveying surface.

[0044] When the permanent magnet 10 is positioned horizontally away from the coil 25 rather than directly above it, a thrust can be generated in the permanent magnet 10 by passing a current through the coil 25. The force that attracts the permanent magnet 10 (attraction force) and the force that repels it (repulsion force) can be controlled by the direction of the current, i.e., the direction of the magnetic flux generated by the coil 25. Furthermore, these thrusts can also be controlled by the current value.

[0045] <Principles of location estimation> Core 22 is made of a magnetic material. The magnetic flux passing through core 22 has the property that it becomes more difficult to pass as the magnetic flux increases. When a voltage is applied to winding 21 to pass a current, a magnetic flux generated by the current is generated in core 22. Therefore, core 22 generates a magnetic flux due to permanent magnet 10 and a magnetic flux generated by the current passed through winding 21.

[0046] The magnetic flux generated by passing a current through the winding 21 is proportional to the value of the current. The proportionality constant in this case is called inductance. The inductance changes depending on the saturation state of the magnetic circuit, which includes magnetic materials such as the core 22, i.e., the saturation characteristics of the core 22.

[0047] When core 22 becomes saturated, the inductance changes depending on the magnitude of the magnetic flux generated in core 22. In other words, the inductance of winding 21 changes depending on the magnitude of the magnetic flux of permanent magnet 10. This means that the inductance of winding 21 changes depending on the position of permanent magnet 10.

[0048] 4 is a graph showing an example of the position characteristic of the inductance of the coil 25. The horizontal axis represents the distance from the permanent magnet 10 to the coil 25, and the vertical axis represents the inductance L of the coil 25.

[0049] In this figure, the inductance L is an increasing function of the distance.

[0050] The voltage V generated in the winding 21 is expressed by the following equation (1).

[0051] V=-dφ / dt …(1) In the formula, φ is the magnetic flux and t is time.

[0052] Furthermore, if the current is I and the inductance is L, the following relational expression (2) holds.

[0053] dI / dt=(1 / L)×(dφ / dt) …(2) From the above equations (1) and (2), the following relational expression (3) is obtained.

[0054] dI / dt=-V / L …(3) In other words, when a constant voltage is applied to winding 21, the time derivative of the supplied current I changes depending on the magnitude of inductance L, as shown in equation (3) above. This means that the way the supplied current rises when a voltage is applied differs. In other words, by detecting inductance L of winding 21, which changes depending on the position of permanent magnet 10, the position of permanent magnet 10 that affects inductance L can be determined.

[0055] <Specimen position estimator 112> 5 is a graph showing an example of the position characteristic of the time rate of change of the current flowing through the coil 25. The horizontal axis represents the distance from the coil 25 to the permanent magnet 10, and the vertical axis represents the time rate of change dI / dt of the current flowing through the coil 25.

[0056] In this figure, dI / dt is a decreasing function of distance.

[0057] The position characteristic of dI / dt as shown in this figure is acquired in advance and stored, for example, as table data in the specimen position estimator 112 (FIG. 3). In the specimen position estimator 112, dI / dt is calculated from the current detected by the current detection unit 30, and input into the specimen position estimator 112. The position of the specimen container having the permanent magnet 10 is estimated by referring to the table data.

[0058] In summary, the specimen position estimator 112 has data on the time rate of change or inductance of the coil current on the transport surface, which is determined by the positional relationship between the magnetic body and the coil, and estimates the position of the transported object using the measured value of the current flowing through the coil.

[0059] <Electrified coil switching determiner 113> FIG. 6 is a configuration diagram showing an example of the energized coil switching determiner of FIG.

[0060] 6, the energized coil switching determiner 113 includes an estimated position comparator 160. In the estimated position comparator 160, a criterion for determining an output relative to an input is set, as shown in the graph schematically illustrated in the figure. In this graph, when the input value is A or more, the output value is Lo (e.g., 0), and when the input value is less than A, the output value is Hi (e.g., 1).

[0061] The operation of the estimated position comparator 160 in such a setting is as follows.

[0062] The estimated position by the specimen position estimator 112 is input to the estimated position comparator 160. The estimated position comparator 160 compares the estimated position (input value) with a preset value or a judgment value provided by a higher-level controller (not shown) or the like, and outputs a Hi or Lo signal (energized coil switching signal). That is, when the specimen container having the permanent magnet 10 is attracted to the energized coil and approaches closer than the judgment position (A in the example of FIG. 6), the comparator outputs Hi (for example, 1).

[0063] <The meaning of initial voltage and its importance> FIG. 7 is a graph showing the position of the coil that applies a thrust when energized to the sample folder being transported, and the velocity of the sample folder.

[0064] In this figure, the specimen folder 11 is shown moving above one of the coils 25 arranged in a grid pattern in the x-axis and y-axis directions below the xy plane, which is the transport surface, i.e., above a row of coils arranged in a straight line in the x-axis direction. The specimen folder 11 has a permanent magnet.

[0065] In the figure, in the graph at the bottom, the horizontal axis represents the position (relative distance) based on coil number #0, and the vertical axis represents the energized coil number. Meanwhile, in the graph at the top, the horizontal axis matches the graph at the bottom, and the vertical axis represents the speed of the specimen holder. Here, an example is shown in which 13 coils 25 are arranged in a line, spaced 20 mm apart.

[0066] The middle section of the figure schematically shows the arrangement of the sample folder 11, the transport surface 12, and the coils 25. The 13 coils 25 shown in the middle section are assigned coil numbers from #0 to #12.

[0067] As shown in the graph at the bottom, the specimen folder 11 is moved from the left to the right in the drawing by sequentially energizing the energizing coils indicated by the numbers.

[0068] Specifically, this example shows the specimen folder 11 moving from coil numbers #1 to #11 at a set speed of 0.5 m / s. More specifically, coil numbers #1, #2, and #3 are sequentially energized to accelerate to the set speed of 0.5 m / s. Thereafter, while coil numbers #4 to #9 are energized, the voltage applied to the coils is adjusted so that the specimen folder 11 moves at a constant speed (constant speed region). Then, coil numbers #10 and #11 are energized to decelerate and stop the specimen folder 11.

[0069] 2, the magnetic force acting on the sample folder 11 varies depending on the distance between the permanent magnet 10 and the coil 25 and the current flowing through the coil 25. Furthermore, even if the magnetic force acting on the sample folder 11 is constant, the speed at which the sample folder 11 moves is not necessarily constant depending on the mass of the sample container and the amount (mass) of the sample placed on the sample folder 11, the friction coefficient of the transport surface 12, etc. In particular, when switching the coil 25 to which current is applied, the magnetic force acting on the sample folder 11 is likely to become discontinuous.

[0070] Furthermore, when the coil driver 50 performs PWM control, it applies a pulsed voltage and controls the effective voltage value using the duty ratio. As a result, there are periods when the voltage output from the coil driver 50 is zero. In other words, the current flowing through the coil 25 contains a ripple component. Therefore, even in a constant speed region, speed fluctuations actually occur.

[0071] Furthermore, the coefficient of friction of the conveying surface 12 changes due to deterioration over time, dirt and dust on the conveying surface 12, and temperature and humidity. For this reason, it is necessary to detect the speed of the specimen folder 11, which changes from moment to moment, and control the thrust.

[0072] In order to suppress structurally generated thrust pulsation when controlling the speed of the specimen holder 11 by sequentially switching the energized coils, it is important not only to control the current flowing through the coils 25 but also to appropriately control the current when switching the energized coils 25. The current when switching the energized coils 25 is controlled by the initial voltage immediately after switching the energized coils 25 and the voltage at the initial stage of the period during which current is flowing to a specific coil 25.

[0073] The initial voltage refers to the voltage output by the coil driving unit 50 immediately after switching the coil 25 to be energized and at the beginning of the period during which current is being applied to a specific coil 25 (for example, the first 30% of the energization period).

[0074] <Initial voltage command generator 114> FIG. 8 is a configuration diagram showing an example of the initial voltage command generator of FIG.

[0075] In FIG. 8, the initial voltage command generator 114 includes an average speed calculation means 170 (average speed calculation unit) and a control gain multiplier 180.

[0076] The average speed calculation means 170 calculates the average speed and determines the difference between the calculated average speed and a speed command value from a higher-level controller (not shown), that is, the error.

[0077] The control gain multiplier 180 generates an initial voltage command using the calculated error. There are several possible configurations for the control gain multiplier 180, and for example, a proportional integral controller (PI controller), an integral controller (I controller), etc. can be applied.

[0078] For example, if the specimen folder 11 is heavy or the coefficient of friction of the conveying surface is high, the conveying speed will decrease even if a predetermined thrust is controlled to act on the specimen folder 11. In this case, the difference between the speed command value and the average speed will be positive, and by amplifying it with the control gain multiplier 180, the voltage applied to the coil 25 will be increased to increase the insufficient speed. As described above, when the coil driver 50 is driven by a PWM signal, the duty ratio will increase.

[0079] It should be noted that the initial voltage command generator 114 can be configured in several other ways in addition to the example shown in this figure.

[0080] In this figure, an initial voltage command is created based on the average speed data up until the current-carrying coil is switched.

[0081] Next, the method of calculating the average speed in the average speed calculation means 170 will be described.

[0082] Figure 9 is a graph showing the change in the speed of the transported specimen folder over time. The horizontal axis represents time, and the vertical axis represents speed. In the figure, downward-pointing triangles indicate the timing of switching the energized coil. The downward-pointing triangles are spaced at equal intervals, indicating that the energized coils are switched sequentially.

[0083] Time t shown in this figure i When switching the energized coil at the timing, an initial voltage command for the next coil to be energized is created. The average speed used in this process can be calculated using data on the position of the specimen holder over a predetermined period of time.

[0084] Examples of such periods include the following four:

[0085] The first is at time t i The current flow time of the coil that was energized before switching the energized coil (time t i-1 From time t i The second is a period B during which multiple energized coils are switched to energize, the third is a period C which is part of the period during which a certain energized coil is energized, and the fourth is a period D which includes one switching timing. These periods may be, for example, on the order of several milliseconds.

[0086] FIG. 10 is a configuration diagram showing another example of the initial voltage command generator of FIG.

[0087] 10, the initial voltage command generator 114 includes an average current calculation means 171 (average current calculation unit) and a control gain multiplier 180. That is, the average current calculation means 171 is used instead of the average speed calculation means 170 in the example of FIG.

[0088] The average current calculation means 171 calculates the average current, and determines the difference between the calculated average current and a current command value from a higher-level controller (not shown), that is, the error.

[0089] The control gain multiplier 180 uses the determined error to generate an initial voltage command. The control gain multiplier 180 may be configured in the same manner as in the example of FIG.

[0090] FIG. 11 is a configuration diagram showing another example of the initial voltage command generator of FIG.

[0091] 11, the initial voltage command generator 114 includes acceleration calculation means 172 (acceleration calculation unit) and a control gain multiplier 180. That is, the acceleration calculation means 172 is used instead of the average speed calculation means 170 in the example of FIG. 8. Here, the acceleration may be an average value over a predetermined period.

[0092] The acceleration calculation means 172 calculates the acceleration and determines the difference between the calculated acceleration and an acceleration command value from a higher-level controller (not shown), that is, the error.

[0093] The control gain multiplier 180 uses the determined error to generate an initial voltage command. The control gain multiplier 180 may be configured in the same manner as in the example of FIG.

[0094] In the above example, the case where the average values ​​of the speed, current, and acceleration are mainly used is described, but the initial voltage command can also be created using the maximum value, minimum value, effective value, etc. over a predetermined period of time in addition to the average values.

[0095] Figure 14 is a graph showing an example of the velocity and output voltage of the specimen folder in the acceleration region. The vertical axis of the upper graph represents the velocity of the specimen folder, showing the process of the specimen folder starting to move from a stopped state and accelerating. The vertical axis of the lower graph represents the duty width (equivalent to the output voltage) of the voltage pulse output from the coil driver 50. In both graphs, the horizontal axis represents the position of the specimen folder.

[0096] As shown on the horizontal axis, the specimen holder starts moving from a stationary position A, passes through positions B and C, and then accelerates.

[0097] As shown in the graph at the bottom, the duty between A and B is set to 60%, and the duty between B and C is set to 70%.

[0098] In this example, the relationship between the gradient of the speed command value and the duty is assumed to be known, and this relationship is stored as a database.

[0099] As shown in this figure, when a voltage pulse with a duty of 60% is applied, the speed at which the specimen holder passes through position B is v ref Let us assume that:

[0100] However, in reality, the coefficient of friction may be high due to, for example, dirt on the conveying surface or deterioration over time. In this case, if the duty is set according to the relational expression in the database, even if the thrust acting on the permanent magnet of the specimen holder is the same, the speed when passing position B will be a low value of v1, as shown in the figure.

[0101] In such a case, the change in speed between A and B, that is, the acceleration, is calculated by the acceleration calculation means 172 (FIG. 11), and the difference from the acceleration command is amplified by the control gain multiplier 180 to control the initial voltage command.

[0102] 14, the duty increments indicated by diagonal lines are the output by the initial voltage command generator 114. Because the duty of 60% set between A and B was not sufficient, the duty between B and C was increased by 10% to 70%.

[0103] It is desirable to perform control to update the output by the initial voltage command generator 114 every time the coil to be energized is switched.

[0104] In this figure, the energized coil is set to be switched at position B, and the duty is changed at the timing of switching, while the duty is kept constant at other positions.

[0105] The timing of changing the duty is not limited to this example, and the duty may be changed while the same coil is energized. Also, the duty may be changed more frequently to maintain the desired speed.

[0106] 14 shows an example in which the speed of the specimen folder 11 is lower than the set value (=command value), but of course, the speed may also exceed the set value. In that case, the output from the initial voltage command generator 114 is controlled to be lower than a predetermined duty.

[0107] In the above example, only the acceleration region has been described, but similar control is possible for the deceleration region as well.

[0108] In summary, when switching the coil to be energized, the calculation unit 40 adjusts the width of the pulse voltage based on the position of the transported object, such as the specimen folder 11, during a predetermined period prior to the energization switching and the time at which the object has passed that position, so as to stabilize the speed or acceleration of the transported object, and outputs the adjusted voltage to the coil driver. The calculation unit 40 may also adjust the width of the pulse voltage based on the current flowing through the energized coil, so as to stabilize the speed or acceleration of the transported object, and output the adjusted voltage to the coil driver. Here, "so as to stabilize the speed or acceleration of the transported object" means that the speed in the constant velocity region is kept as constant as possible, and that the acceleration in the acceleration and deceleration regions is kept as constant as possible.

[0109] In addition, it is desirable that the speed or acceleration of the transported object or the current flowing through the coil during a predetermined period before the current switching, which is used to determine the width of the pulse voltage, be any of their maximum, minimum, average, or effective values.

[0110] <Voltage command generator 111> FIG. 12 is a configuration diagram showing an example of the voltage command generator of FIG.

[0111] In FIG. 12, the voltage command generator 111 includes a control gain multiplier 181 and a winding resistance gain multiplier 190.

[0112] The control gain multiplier 181 receives the difference between a current command value given by a higher-level controller (not shown) and a current detection value.

[0113] On the other hand, a current command value is input to a winding resistance gain multiplier 190 .

[0114] The output of the control gain multiplier 181 is then added to the output of the winding resistance gain multiplier 190, and the value obtained by this addition is further added to the initial voltage command that is the output of the initial voltage command generator 114. The value obtained as a result becomes the voltage command that is the output of the voltage command generator 111. Here, the voltage command may be a duty.

[0115] In other words, in the example shown in the figure, in addition to an element that obtains the voltage drop in coil 25 in a feedforward manner based on the current command value via winding resistance gain multiplier 190 and an element that obtains in a feedback manner to compensate for the difference between the current command value and the detected current value, the initial voltage command value from initial voltage command creator 114 described above is also added.

[0116] The initial voltage command value from the initial voltage command generator 114 may be configured to be triggered by a current-carrying coil switching signal from the current-carrying coil switching determiner 113 and output only when the current-carrying coil is switched.

[0117] As described above, the conveying device of this embodiment can be configured so that when switching the energized coil, the width of the pulse voltage applied to the coil is determined according to the average speed of the conveyed object or the average current flowing through the coil during the coil energization period before switching.

[0118] This configuration can suppress structurally generated thrust pulsations when controlling the position of the transported object by sequentially switching the energized coils. Furthermore, even if the number of transported objects increases, each transported object can be transported stably. [Example]

[0119] Regarding the second embodiment, differences from the first embodiment will be described, and a description of the same configurations will be omitted.

[0120] FIG. 13 is a functional block diagram showing the configuration of the transport device of the second embodiment.

[0121] In this figure, the transport device 100 includes a coil 25, a coil driving unit 50, and a calculation unit 40.

[0122] The calculation unit 40 includes a voltage command generator 111, a current-carrying coil switching determiner 113a, and an initial voltage command generator 114. In the vicinity of the coil 25, a position detection means 60 is provided.

[0123] In this figure, the specimen position estimator 112 and the current detection unit 30 of Figure 3 are not provided. A position detection means 60 (position detector) is provided instead of the current detection unit 30. The position detection means 60 detects the position of the permanent magnet 10 provided in the specimen folder 11.

[0124] Examples of the position detection means 60 include a Hall element and a linear encoder. A Hall element is a sensor that converts a magnetic field generated by a magnet or current into an electric signal and outputs it, and is used as a position sensor that indirectly detects the position of a magnet. For example, if the permanent magnet 10 approaches the Hall element and the magnetic flux density exceeds a predetermined value, the Hall element outputs a High signal, and if the magnetic flux density is below the predetermined value, the Hall element outputs a Low signal, thereby making it possible to determine whether the permanent magnet 10 has approached the coil 25 that is in an energized state.

[0125] When the position detection means 60 is configured using a Hall element, the energized coil switching determiner 113a can use the High or Low signal based on the Hall element as the output of the estimated position comparator 160 (FIG. 6) as is.

[0126] The transport device 100 can transport multiple sample folders 11 simultaneously, and some or all of the contents of the present disclosure can be applied when switching the coils 25 to be energized in order to transport each sample folder 11. Furthermore, there may be multiple upper controllers not shown in the present disclosure, and initial voltage command information may be exchanged between them.

[0127] In summary, it is desirable that the width of the pulse voltage is determined in the calculation unit 40 based on the speed or acceleration of the transported object during a predetermined period before the power supply is switched, the current flowing through the coil, or the time it takes to pass between two predetermined positions.

[0128] The present disclosure is not limited to the above-described embodiments, but includes various modifications. Furthermore, the present disclosure is not necessarily limited to those having all of the above-described configurations.

[0129] Furthermore, the above-described configurations, functions, processing units, processing procedures, etc. may be partly or entirely realized in hardware by, for example, designing them as integrated circuits, etc. Furthermore, the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. [Explanation of symbols]

[0130] 10: permanent magnet, 11: specimen folder, 12: conveying surface, 21: winding, 22: core, 25: coil, 30: current detection unit, 40: calculation unit, 50: coil drive unit, 55: power supply, 60: position detection means, 100: conveying device, 111: voltage command generator, 112: specimen position estimator, 113: energized coil switching determiner, 114: initial voltage command generator, 160: estimated position comparator, 170: average speed calculation means, 171: average current calculation means, 172: acceleration calculation means, 180, 181: control gain multiplier, 190: winding resistance gain multiplier.

Claims

1. A conveying device that conveys an object having a magnetic body, a plurality of coils that generate thrust for transporting the object; a coil driver that applies a pulsed voltage to each of the plurality of coils; a calculation unit, When switching the coil to be energized, the calculation unit creates an initial voltage command using the difference between the speed of the transported object and a speed command value, the difference between the current flowing in the coil and a current command value, or the difference between the acceleration of the transported object and an acceleration command value, based on the position of the transported object and the time it passed that position during a predetermined period before the energization switching, or the current flowing in the energized coil, thereby determining the width of the pulse-like voltage so that the speed or acceleration of the transported object is stabilized, and outputting the pulse-like voltage to the coil drive unit.

2. 2. The conveying device according to claim 1, wherein the width of the pulsed voltage is determined based on the velocity or acceleration of the conveyed object during the predetermined period before the current switching, the current flowing through the coil, or the time required for the conveyed object to pass between two predetermined positions.

3. A conveying surface; a position estimation unit, 2. The conveying device according to claim 1, wherein the position estimation unit has data on the time rate of change or inductance of the current of the coil on the conveying surface, which is determined by the positional relationship between the magnetic body and the coil, and estimates the position of the conveyed object using a measured value of the current flowing through the coil.

4. 3. The conveying device according to claim 2, wherein the velocity or acceleration of the conveyed object or the current flowing through the coil during the predetermined period before the current switching, which is used to determine the width of the pulsed voltage, is any one of their maximum value, minimum value, average value, and effective value.

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