Motor system and gripping device

Abstract

Provided are a motor system and a gripping device capable of applying a force of an arbitrary magnitude, which is determined by setting, to an object by using a stepping motor. A stepping motor 105 applies a force to an object via a gripping mechanism 104. An angle sensor 106 detects a rotor angle of the rotor. A driver circuit 102 is configured to be able to: control a magnetic field vector by the stator to an arbitrary electrical angle; and control the current value of a motor current to be constant. A controller 101 receives a rotor angle from the angle sensor 106 and performs feedback control on the stepping motor 105 via the driver circuit 102. The controller 101 controls the stepping motor 105 so that an advance angle, which is the difference between the electrical angle of the magnetic field vector and the rotor angle, maintains a constant set advance angle when applying the force to the object.

Description

Motor system and gripping device

[0001] The present invention relates to a motor system and a gripping device, and more particularly to a motor system including a stepping motor and an angle sensor, and a gripping device to which the motor system is applied.

[0002] Patent Document 1 discloses an automated analysis system that enables the unplugging and replugging of different specimen containers. The system includes a stopper opening / closing mechanism, a control unit, and a stopper transport mechanism. The control unit stores the correspondence between specimen containers and their corresponding stoppers. The stopper opening / closing mechanism removes stoppers from specimen containers and replugs specimen containers after sample dispensing based on the correspondence stored in the control unit. The stopper transport mechanism transports stoppers removed by the stopper opening / closing mechanism at the unplugging position to the replugging position.

[0003] Patent Document 2 discloses a slide glass transport device capable of transporting a slide glass while retaining a liquid thereon. The transport device includes a gripping unit capable of gripping and releasing the slide glass and a drive unit capable of moving the gripping unit. The gripping unit has multiple fingers and a finger drive unit capable of operating the multiple fingers. Each of the multiple fingers includes a support unit capable of supporting a portion of the underside of the slide glass and a pointed portion capable of contacting a gripping point located on the side of the slide glass.

[0004] JP 2012-159317 A International Publication No. 2023 / 281951

[0005] For example, as shown in Patent Documents 1 and 2, a method of using an actuator is generally known as a method of causing a gripping mechanism of an automated robot or the like to grip an object such as a specimen container, a stopper, or a slide glass. The actuator may be configured using, for example, an air cylinder powered by compressed air, or a solenoid or motor powered by electricity.

[0006] When a stepping motor is used as the actuator of the gripping mechanism, the motor is typically controlled by an open loop. In this case, the control unit cannot control the stepping motor to stop applying pulses the moment the object is gripped, which can easily cause the stepping motor to lose synchronization. Furthermore, even if the control unit detects the gripping state by some means and stops applying pulses, the stepping motor itself can only remain stopped at the position at which the pulses stopped. This can make it very difficult to continue gripping the object with a stable gripping force.

[0007] As described above, when a stepping motor is used as an actuator for a gripping mechanism, it is extremely difficult to properly grip objects of various sizes, shapes, and hardness, and to control the gripping force to an arbitrary magnitude so as not to damage the object.Furthermore, it is extremely difficult to control the force to an arbitrary magnitude when applying various forces to an object, not limited to such gripping forces.

[0008] The present invention has been made in consideration of the above, and one of its objects is to provide a motor system and a gripping device that can apply a force of any magnitude determined by settings to an object using a stepping motor.

[0009] The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0010] A motor system according to one embodiment includes a stepping motor, an angle sensor, a driver circuit, and a controller. The stepping motor has a rotor, a stator, and a coil attached to the stator, and applies force to an object via a power transmission mechanism. The angle sensor detects the rotor angle of the rotor. The driver circuit is configured to be able to control the magnetic field vector generated by the stator to any electrical angle and to control the current value flowing through the coil to a constant value. The controller inputs the rotor angle from the angle sensor and performs feedback control on the stepping motor via the driver circuit. Here, the controller controls the stepping motor so that, when applying force to the object, the lead angle, which is the difference between the electrical angle of the magnetic field vector and the rotor angle, maintains a constant set lead angle.

[0011] According to the embodiment, it is possible to apply a force of any magnitude determined by settings to an object using a stepping motor.

[0012] 1 is a schematic diagram showing an example of the configuration of a motor system according to a first embodiment; FIG. 2 is a schematic diagram showing an example of the configuration and operation of the gripping mechanism shown in FIG. 1; FIG. 2 is a diagram showing the relationship between the rotor angle and the electrical angle in a stepping motor during press control; FIG. 1 , FIG. 2A, and FIG. 2B are flowcharts showing an example of the processing content of a controller executed from the start of positioning control to the completion of pressing against an object; FIG. 4 is a flowchart showing an example of the processing content of a controller executed to maintain a pressing state after it is determined that pressing is completed in the processing shown in FIG. 4; FIG. 4 and FIG. 5 are diagrams showing an example of experimentally measured characteristics of pressing force relative to motor current, assuming that the set lead angle is constant; FIG. 8A is a flowchart showing an example of the processing content executed by the controller shown in FIG. 1 to determine a gripping state in a motor system according to a second embodiment; FIG. 8B is a diagram showing an example of change in rotor angle over time when the object gripped by the gripping mechanism shown in FIG. 2 is hard, in the motor system according to the second embodiment; FIG. 8C is a diagram showing an example of change in rotor angle over time when the object gripped by the gripping mechanism shown in FIG. 2 is soft, unlike FIG. 8A. 13 is a schematic diagram showing an example of the configuration of an automatic analysis system to which a motor system according to a third embodiment is applied. FIG. 14 is a schematic diagram showing an example of the configuration of a rack and specimen containers in FIG. 9. FIG. 15 is a schematic diagram showing an example of the capping operation by the capping opening and closing mechanism in FIG. 16. FIG. 16 is a schematic diagram showing an example of the dispensing operation by the specimen probe in FIG. 17. FIG. 17 is a schematic diagram showing an example of the capping operation by the capping opening and closing mechanism in FIG. 18. FIG. 18 is a schematic diagram showing an example of the configuration of a slide-type specimen processing system to which a motor system according to a third embodiment is applied. FIG. 19 is a perspective view showing a schematic example of the configuration of the slide glass transport device in FIG. 12. FIG. 19 is a schematic diagram showing an example of the configuration of a finger in FIG. 13. FIG. 19 is a schematic diagram showing an example of the configuration of a gripping device as a comparative example in the automatic analysis system shown in FIG. 9 or the slide-type specimen processing system shown in FIG. 12.

[0013] In the following embodiments, it goes without saying that the components (including element steps, etc.) are not necessarily essential unless otherwise specified or considered to be clearly essential in principle. Similarly, in the following embodiments, when referring to the shape, positional relationship, etc. of components, etc., it is intended to include those that are substantially similar or similar to the shape, etc., unless otherwise specified or considered to be clearly not essential in principle. The same applies to the above numerical values ​​and ranges.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all drawings for explaining the embodiments, the same components are generally designated by the same reference numerals, and repeated description thereof will be omitted.

[0015] (First embodiment) <Outline of motor system> Fig. 1 is a schematic diagram showing an example configuration of a motor system according to a first embodiment. The motor system shown in Fig. 1 includes a controller 101, a driver circuit 102, an angle sensor detection circuit 103, a gripping mechanism 104, a stepping motor 105, and an angle sensor 106. The gripping mechanism 104 is an example of a power transmission mechanism, and is a mechanism for gripping an object. In general, the motor system uses the stepping motor 105 to control the gripping force, or in other words, the pressing force, applied to the object by the gripping mechanism 104.

[0016] As is widely known, the stepping motor 105 has a rotor, a stator, and a coil attached to the stator. The stepping motor 105 applies a force, in this example, a gripping force, to an object via a power transmission mechanism, in this example, a gripping mechanism 104. The driver circuit 102 controls the direction and amount of rotation of the stepping motor 105 by passing a current through the coil in the motor using a switch circuit such as an H-bridge circuit. In this specification, the stepping motor is also simply referred to as a motor.

[0017] An angle sensor 106 that detects the rotor angle is installed on the rotor inside the stepping motor 105. More specifically, an angle sensor detection circuit 103 detects the rotor angle of the rotor based on a signal from the angle sensor 106. The angle sensor 106 is, for example, a rotary encoder that can continuously count 360 degrees or more, and it does not matter whether it is an absolute type or an incremental type. In this case, the angle sensor detection circuit 103 detects the rotor angle by decoding the encoder signal from the angle sensor 106.

[0018] The controller 101 performs feedback control of the stepping motor 105 via the driver circuit 102 based on the rotor angle detected by the angle sensor 106, more specifically, the angle sensor detection circuit 103. The controller 101 can be realized by program processing using a processor such as a microcontroller, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like, for example.

[0019] Here, the controller 101 and the driver circuit 102 have a configuration compatible with a constant current drive system. Examples of constant current drive systems include a PWM chopping system in which each pulse applied to the stepping motor 105 is configured with a PWM (Pulse Width Modulation) signal having multiple cycles. In the PWM chopping system, the duty ratio of the PWM signal is controlled based on the error between a target current and a detected current. For example, the controller 101 generates such a PWM signal and supplies it to the driver circuit 102 as a switching signal. However, the PWM chopping system is not limited to this, and other constant current drive systems may be used as long as they can control the effective current.

[0020] Furthermore, it is desirable that the controller 101 and the driver circuit 102 have a configuration compatible with a microstep driving method, which is a method of controlling the direction of a magnetic field vector formed by a stator by flowing current at a predetermined ratio through a multi-phase (for example, two-phase) coil and synthesizing the vectors of the multi-phases.

[0021] The microstep driving method allows the magnetic field vector, and therefore the electrical angle of the rotor, to be controlled with high spatial resolution. As a specific example, the basic step angle of a two-phase stepping motor 105, i.e., the angle of rotation per pulse applied, is typically 1.8 degrees. The microstep driving method allows this 1.8 degrees to be broken down into smaller step angles. When the microstep driving method is used, for example, the controller 101 simply supplies a PWM signal for each phase based on the current value for each phase to the driver circuit 102.

[0022] 2A and 2B are schematic diagrams showing an example of the configuration and operation of the gripping mechanism 104 in FIG. 2A and 2B include a retainer 201, a ball screw 202, a nut 203, and grippers 206a and 206b. One end of the ball screw 202 is attached to the retainer 201, and the other end is attached to the rotation shaft of the stepping motor 105. The nut 203 is provided so that the ball screw 202 is inserted into it. The grippers 206a and 206b are fixed to the retainer 201 and the nut 203, respectively.

[0023] 2A , when the ball screw 202 is rotated using the stepping motor 105, the nut 203, and therefore the gripper 206b, moves forward or backward on the axis of the ball screw 202 depending on the direction and amount of rotation of the stepping motor 105. This controls the positioning of the gripper 206b. Note that instead of the ball screw 202, for example, a rack-and-pinion mechanism or the like may be used, which combines a plate- or rod-shaped gear called a rack with a small gear called a pinion.

[0024] On the other hand, when ball screw 202 is rotated in a direction that narrows the distance between grippers 206a and 206b, grippers 206a and 206b come into contact with object 207 and grip object 207 with a constant gripping force, as shown in Fig. 2B. In this specification, the control that causes gripping mechanism 104 to grip object 207 with a constant gripping force, as shown in Fig. 2B, is referred to as pressing control.

[0025] 3 is a diagram showing the relationship between the rotor angle and electrical angle in stepping motor 105 in FIG. 2 during pressing control. In this example, a two-phase stepping motor 105 consisting of phases A and B is used as an example. Stepping motor 105 has a stator 301, a rotor 302, and phase A coils 303 and phase B coils 304. Phase A coils 303 and phase B coils 304 are alternately attached to a plurality of slots in stator 301. In this example, six slots are shown for simplicity of illustration.

[0026] The rotor 302 is made up of a permanent magnet and is installed at the center of the stator 301. The rotor 302 is the rotation axis of the stepping motor 105 and rotates the ball screw 202 shown in FIGS. 2A and 2B. Here, the angle detected by the angle sensor 106 is also the rotor angle (RA) 305 of the rotor 302. Meanwhile, the driver circuit 102 passes current through the A-phase coil 303 and the B-phase coil 304, respectively, causing the stator 301 to generate a magnetic field vector. In the specification, the angle component of this magnetic field vector is referred to as the electrical angle (EA) 306.

[0027] As shown in FIG. 2A , as long as normal positioning control is performed, the electrical angle (EA) 306 and the rotor angle (RA) 305 are always equal. On the other hand, as shown in FIG. 2B , when pressing control is performed, if pulses continue to be applied to the stepping motor 105 even after the gripper 206 b touches the target object 207, the rotor angle (RA) 305 will not be able to keep up with the evolving electrical angle (EA) 306. This can easily lead to step-out. As a result, gripping the target object 207 can become very difficult. If step-out occurs, initialization processing is performed to return the stepping motor 105 to its origin, and internal processing is performed to make the electrical angle 306 after the return to the origin equal to the rotor angle 305.

[0028] Furthermore, even if some means is provided to detect that the gripper 206b has touched the object 207 and stop the application of pulses, it is not necessarily possible to properly grip the object 207. That is, in this case, the positional relationship between the gripper 206b and the object 207 is fixed at the positional relationship at the time when the gripper 206b touched the object 207. However, for example, if the object 207 is made of a slightly soft material, this fixed positional relationship may not be enough to obtain a pressing force that can continuously grip the object 207.

[0029] <Details of the Controller> Therefore, it is useful to obtain a pressing force of any magnitude without causing the stepping motor 105 to lose synchronization according to the flowcharts shown in Figures 4 and 5. Figure 4 is a flowchart showing an example of the processing content of the controller 101 executed from the start of positioning control to the completion of pressing against the target object 207 in Figures 1, 2A, and 2B. Figure 5 is a flowchart showing an example of the processing content of the controller 101 executed to maintain the pressing state after it is determined that pressing is complete in the processing shown in Figure 4. The controller 101 executes the flowcharts shown in Figures 4 and 5, for example, by having a processor execute a control program stored in a memory.

[0030] 4, after starting processing, the controller 101 waits until the timing for applying the next pulse (step S401). When the timing for applying the pulse arrives (step S401: Yes), the controller 101 applies a pulse to the stepping motor 105 via the driver circuit 102, causing the stepping motor 105 to rotate by one pulse, for example, the basic step angle (step S402). The controller 101 then recalculates the electrical angle (EA) changed by one pulse (step S403). The controller 101 also detects the rotor angle (RA) using the angle sensor 106 (step S404).

[0031] Next, the controller 101 calculates "lead angle Φ = electrical angle (EA) - rotor angle (RA)" using the electrical angle (EA) recalculated in step S403 and the rotor angle (RA) detected in step S404 (step S405). Then, the controller 101 determines whether the calculated lead angle Φ matches a predetermined set lead angle (step S406). As a specific example, if the basic step angle of the stepping motor 105 is 1.8 degrees, the set lead angle may be the same as the basic step angle, 1.8 degrees.

[0032] Here, in step S406, if the lead angle Φ does not match the set lead angle, specifically, if the lead angle Φ is 0 or a value between 0 and the set lead angle, the gripper 206b is not in contact with the target object 207 or has just come into contact with it. In other words, this state is a state in which the gripper 206b is approaching the target object 207 due to the normal positioning control shown in FIG. 2A. Therefore, the controller 101 returns to step S401 and waits for the timing of applying the next pulse (step S406: No).

[0033] On the other hand, if the lead angle Φ matches the set lead angle in step S406, the gripper 206b is in contact with the object 207 and is pressing the object 207 with a predetermined pressing force. That is, in this state, a torque that attempts to align the rotor angle (RA) with the electrical angle (EA), and therefore a pressing force, is generated based on the magnitude of the set lead angle, etc., in Fig. 2B. Therefore, the controller 101 determines that pressing is complete and performs control to maintain the pressing force in accordance with the flowchart for maintaining the pressing state shown in Fig. 5 (step S406: Yes).

[0034] 4, even if the lead angle Φ and the set lead angle match, this matched state may not be maintained because, for example, the rotor angle (RA) may change immediately thereafter depending on the material, such as hardness, of the object 207. In other words, the pressing force may not be kept constant. Therefore, the controller 101 executes the flowchart shown in FIG. 5. The controller 101 repeatedly executes the process shown in FIG. 5 at regular intervals, such as several tens of kHz, using a timer interrupt or the like, during the period during which it is necessary to continue gripping the object 207.

[0035] 5, after starting processing, the controller 101 detects the rotor angle (RA) (step S501). Subsequently, the controller 101 calculates "lead angle Φ = electrical angle (EA) - rotor angle (RA)" using the detected rotor angle (RA) and the current electrical angle (EA) (step S502). Next, the controller 101 determines whether the calculated lead angle Φ matches the set lead angle (step S503). If the lead angle Φ matches the set lead angle in step S503, the controller 101 determines that the gripping state is normal and ends processing (step S503: Yes).

[0036] On the other hand, if the lead angle Φ does not match the set lead angle in step S503 (step S503: No), the controller 101 calculates the rotation direction required to make the lead angle Φ match the set lead angle (step S504). Then, the controller 101 applies one pulse to the stepping motor 105 to rotate the rotor 302 in the calculated rotation direction, thereby rotating the magnetic vector by one step (step S505). Unlike the case of FIG. 4 , this step may be a high-resolution step based on a microstep drive system. The controller 101 then recalculates the electrical angle (EA) obtained by rotating the rotor by one step and stores this electrical angle (EA) for use in the next process (step S506).

[0037] As described above, in the method of the embodiment, control from the start of positioning control to the completion of pressing is performed according to the flowchart shown in Fig. 4, and control to maintain the pressing state thereafter is performed according to the flowchart shown in Fig. 5. This makes it possible to grip the object 207 with a constant pressing force. In other words, by performing feedback control so as to maintain a state in which the lead angle Φ and the set lead angle match, it is possible to grip the object 207 with a constant pressing force regardless of the material of the object 207, such as its hardness, and to maintain the gripping state with a constant pressing force for a required period of time.

[0038] <Regarding Pressing Force> The relationship between motor current and pressing force when the lead angle Φ is controlled to a constant will be described below using mathematical expressions. First, in the gripping mechanism 104 shown in Fig. 2, the gripping force of the grippers 206a, 206b is determined by, for example, the output torque of the stepping motor 105 in the pressing state described with reference to Fig. 5. Here, the torque equation for a two-phase hybrid stepping motor can be expressed by equation (1.1).

[0039] -(e A i A +e B i B ) = τ(dθ / dt)+d / dt{(i A 2 L A ) / 2+(i B2 L B ) / 2} …(1.1) e A : A phase electromotive force e B : B-phase electromotive force i A : A phase current i B : B phase current L A : Self-inductance of A phase L B : Self-inductance of B phase τ: Torque

[0040] In equation (1.1), if the magnetic circuit is linear, there is no mutual inductance between the two phases, so the torque τ is calculated as follows: A and the component τ due to phase B B Then, equations (1.3) and (1.4) can be obtained from equations (1.1) and (1.2).

[0041] τ = τ A +τ B …(1.2) -e A i A = τ A (dθ / dt)+d / dt{(i A 2 L A ) / 2} …(1.3) -e B i B = τ B (dθ / dt)+d / dt{(i B 2 L B ) / 2} … (1.4)

[0042] Here, the electromotive force of each phase is composed of two components, namely, the voltage e generated by the magnetic flux of the permanent magnet interlinking with the coil. g and the electromotive force e due to the current flowing through the self-inductance L Since it is the sum of and, equation (1.3) can be transformed into equation (1.5). Also, the electromotive force e due to self-inductance LA can be expressed by equation (1.6). -(e gA + e LA )i A = τ A (dθ / dt)+d / dt{(i A 2 LA ) / 2} …(1.5) e LA = -(d / dt)(i A L A ) … (1.6)

[0043] Equation (1.7) is obtained from equations (1.5) and (1.6). Some terms included in equation (1.7) can be expanded as in equation (1.8). -e A i A +i A (d / dt)(i A L A ) = τ A (dθ / dt)+d / dt{(i A 2 L A ) / 2} …(1.7) i A (d / dt)(i A L A )-d / dt{(i A 2 L A ) / 2} = i A 2 (dL A / dt)+L A i A (di A / dt)-(L A / 2)(di A 2 / dt)-(i A 2 / 2)(dL A / dt) ... (1.8)

[0044] In equation (1.8), the second and third terms cancel each other out, so equation (1.9) is obtained. Furthermore, from equations (1.7) and (1.9), the torque τ A When we calculate the equation (1.10), we obtain A 2 / 2)(dLA / dt) = (i A 2 / 2)(dL A / dθ)(dθ / dt) …(1.9) τ A = -e gA i A / (dθ / dt)+(I A 2 / 2)(dLA / dθ) … (1.10)

[0045] When exciting a two-phase hybrid stepping motor, sinusoidal currents of the same frequency are passed through the A-phase coil 303 and the B-phase coil 304, so the currents flowing through the A-phase and B-phase coils can be expressed by equations (1.11) and (1.12), respectively. A = -I M sinωt …(1.11) i B = I M cosωt … (1.12)

[0046] Then, from equations (1.2), (1.10), (1.11) and (1.12), equation (1.13) is obtained: τ = C Nr I M sinΦ …(1.13) C: Proportionality constant determined by the motor structure and number of coil turns Nr: Number of rotor teeth I M : Peak current

[0047] In equation (1.13), the torque τ is proportional to sinΦ, so the angle Φ is also called the torque angle and can be expressed by equation (1.14): Φ = Φ i - Φ0…(1.14) Φ i : Electrical angle of target positioning value Φ0: Actual rotor position

[0048] In equation (1.14), Φ, which is the electrical angle of the positioning target value, i is synonymous with ωt, which gives the phase of the current waveform in equations (1.11) and (1.12). During the driving period of the stepping motor 105, the electrical angle Φ given to the stator 301 is i The actual position Φ of the rotor 302 follows, and during the stop period, Φ i =Φ0 holds. Φ i At Φ=Φ0, the torque τ becomes τ=0, so the stopped state is maintained.

[0049] Here, in accordance with formula (1.14), the angle Φ is synonymous with the lead angle Φ in the embodiment. For example, during the pressing control described with reference to FIG. 5, the angle Φ detected by the angle sensor 106 is adjusted so that the lead angle Φ given by formula (1.14) coincides with a fixed set lead angle. ０ For electrical angle Φ i As a result, as can be seen from equation (1.13), the torque τ, i.e., the pressing force, is controlled to be constant.

[0050] In detail, the pressing force is calculated by the peak current I as shown in equation (1.13). Ｍ and the lead angle Φ. In the embodiment, the lead angle Φ is controlled to be constant, so the pressing force varies in proportion to the peak current I Ｍ 6 is a diagram showing an example of experimental results of the characteristics of the pressing force relative to the motor current, assuming that the set advance angle is constant in FIGS. 4 and 5. As shown in FIG. 6, the pressing force is controlled by the motor current, i.e., the peak current I flowing through the A-phase coil 303 and the B-phase coil 304. Ｍ Therefore, based on such characteristics, the motor current can be determined in advance so as to obtain an optimum pressing force according to the material of the object 207, etc.

[0051] 4 and 5, in order to control the lead angle Φ so as to be constant for the target object 207 made of various materials, it may be necessary to control the electrical angle (EA) with high spatial resolution. For this reason, as described above, it is desirable to use a configuration for the controller 101 and the driver circuit 102 that supports a microstep drive system that can further subdivide the basic step angle. On the other hand, if the stepping motor 105 itself has high spatial resolution due to its structure, the microstep drive system is not necessarily required. However, using a stepping motor 105 with such high spatial resolution may increase costs. Therefore, it is preferable to use the microstep drive system from the perspective of reducing costs.

[0052] <Regarding Modifications> The above has been described as an example of a case in which a constant pressing force, i.e., a gripping force, is continuously generated by appropriately setting the motor current value while keeping the lead angle Φ of the stepping motor 105 constant. By applying this method to the gripping mechanism 104 shown in Fig. 2, it is possible to grip the object 207 with an optimal pressing force, and it is possible to achieve control suitable for gripping various objects 207.

[0053] However, the method of the embodiment is not limited to the gripping force of the gripping mechanism 104, but can also be applied to cases where various forces are applied to an object via various power transmission mechanisms. Specifically, the method can be applied to power transmission mechanisms that perform press-fitting, punching, crimping, screwing, capping, etc. For example, a press-fitting mechanism is a mechanism that uses a stepping motor 105 to press an object into an opening, etc.

[0054] The punching mechanism is a mechanism that uses a stepping motor 105 to press a die or the like against an object such as a plate member, thereby punching the plate member with the die. The crimping mechanism is a mechanism that uses a stepping motor 105 to press one end of an object such as a pin passed through a hole, thereby deforming the pin and fixing the pin in the hole. In this way, the press-fitting mechanism, punching mechanism, and crimping mechanism are mechanisms that apply a pressing force to the object. Therefore, the same method as in the cases of Figures 2A and 2B can be applied.

[0055] On the other hand, the screw tightening mechanism and the capping mechanism are mechanisms that rotate an object using, for example, a stepping motor 105. That is, these mechanisms apply a rotational force to an object. These mechanisms have a mechanism that rotates a gripped object in response to the rotation of the stepping motor 105, for example. Even in the various power transmission mechanisms exemplified above, positioning control and control of pressing force, rotational force, etc. can be important technical elements. Therefore, it is beneficial to use the method of the embodiment.

[0056] <Major Effects of the First Embodiment> As described above, in the first embodiment, when a force is applied to an object using the stepping motor 105, feedback control is performed so that a state in which the electrical angle is always maintained advanced by the set lead angle relative to the rotor angle is maintained. As a result, it is typically possible to apply a force of any magnitude determined by setting to the object. Furthermore, in this case, it is not necessary to use an expensive motor such as a servo motor as the actuator of the gripping mechanism, but rather a two-phase stepping motor or the like and an angle sensor can be used, thereby realizing a motor system at low cost.

[0057] Furthermore, because the magnitude of the force can be set arbitrarily, it is possible to apply an optimal force to objects of various shapes and sizes—neither too strong (i.e., not damaging them), nor too weak. If the actuator of the gripping mechanism uses an air cylinder powered by compressed air or a solenoid consisting of an electromagnet and an iron core, the gripping force can be set by adjusting the compressed air pressure or the voltage applied to the solenoid. However, in this case, it is extremely difficult to accurately stop the robot at a desired location during positioning operations other than gripping. In this regard, using a stepping motor allows the high positioning accuracy, which is the stepping motor's greatest advantage, to be utilized in gripping operations.

[0058] (Second Embodiment) <Details of Controller> In the first embodiment, a method for controlling the pressing force to be constant by performing feedback control to maintain the lead angle Φ constant in equation (1.13) has been described. Using this method, optimal grip force control can be performed for the object 207. However, the content of the control cannot be changed depending on the size or grip state of the object 207. Therefore, in the second embodiment, a method for performing pressing control while determining the size and grip state of the object 207 will be described.

[0059] In the second embodiment, as in the first embodiment, control from the start of positioning control to the completion of pressing is performed according to the flowchart shown in Fig. 4, and control to maintain the pressing state thereafter is performed according to the flowchart shown in Fig. 5. However, in the second embodiment, unlike the first embodiment, after pressing is completed, the flowchart shown in Fig. 7 is also executed in parallel with the flowchart shown in Fig. 5.

[0060] 7 is a flowchart showing an example of processing executed by the controller 101 shown in FIG. 1 to determine the gripping state in the motor system according to the second embodiment. The controller 101 repeatedly executes the processing shown in FIG. 7 at regular intervals using a timer interrupt or the like during the period during which it is necessary to continue gripping the target object 207. The regular intervals in this case may be longer than the regular intervals in FIG. 5, for example. The controller 101 also executes the flowchart shown in FIG. 7 by, for example, causing a processor to execute a control program stored in memory.

[0061] 7, after starting the process, the controller 101 detects the rotor angle (RA) (step S701). Next, the controller 101 calculates "lead angle Φ = electrical angle (EA) - rotor angle (RA)" using the detected rotor angle (RA) and the electrical angle (EA) recalculated in step S506 in FIG. 5 (step S702). Next, in step S703, the controller 101 determines whether the lead angle Φ matches the set lead angle (step S703).

[0062] If the advance angle Φ matches the set advance angle in step S703 (step S703: Yes), the controller 101 determines whether the rotor angle (RA) is within a normal range (step S704). That is, for example, in FIG. 2B , a range of rotor angles (RA) corresponding to the range of sizes of the object 207 considered normal is predetermined as the normal range based on the range of sizes of the object 207 considered normal and the mechanical constants of the gripping mechanism 104, such as the gear ratio with the stepping motor 105. The range of rotor angles (RA) is, for example, a range based on the origin position.

[0063] 2B, the gripper 206b may move approximately 10 mm by rotating the stepping motor 105 360 degrees. If the resolution of the stepping motor 105 is 1.8 degrees, the size of the object 207 can be identified with a resolution of 0.05 mm (= 10 mm × (1.8 / 360)).

[0064] In step S704, if the rotor angle (RA) is within the normal range (step S704: Yes), the size of the object 207 is also within the normal range. Therefore, the controller 101 determines that the object 207, whose size is within the normal range, is being gripped (step S706). On the other hand, if the rotor angle (RA) is outside the normal range (step S704: No), the controller 101 determines that the object 207 is being gripped normally with a certain advance angle Φ, but that the size of the object 207 is abnormal (step S707).

[0065] In this way, the controller 101 can detect the size of the object 207 based on the rotor angle (RA) detected after the gripping mechanism 104 grips the object 207, in other words, after the gripper 206b comes into contact with the object 207. As a result, for example, it is possible to verify the authenticity of the object 207, and also to realize a mechanism for performing processing according to the size of the object 207.

[0066] On the other hand, if the lead angle Φ does not match the set lead angle in step S703 (step S703: No), the controller 101 determines whether the lead angle Φ is Φ = 0 (step S705). If Φ = 0 (step S705: Yes), according to the flowchart shown in Fig. 4, even though the target object 207 was once grasped, the value has changed to Φ = 0. Therefore, the controller 101 determines that a grasping failure state has occurred (step S708).

[0067] However, when the process proceeds to step S708, it is possible that the change to Φ = 0 is temporary and that the lead angle Φ will then return to the set lead angle due to, for example, the elasticity of the object 207. For this reason, the controller 101 may proceed to step S708 when, for example, it is determined that Φ = 0 for multiple consecutive cycles.

[0068] Finally, in step S705, if the lead angle Φ is not Φ = 0 (step S705: No), there is a possibility that the pressing state is occurring at a lead angle Φ other than the set lead angle. According to equation (1.13), the pressing force also depends on the lead angle component "sinΦ." Therefore, this state is one in which the target pressing force is not being generated. Therefore, the controller 101 determines that the gripping state is abnormal (step S709). Note that when the controller 101 proceeds to steps S706-S709, it notifies the corresponding content to, for example, a higher-level controller (not shown). In response, the higher-level controller executes predetermined abnormality processing, etc.

[0069] In this way, by executing the control flow for maintaining the pressing state shown in FIG. 5 and the gripping state determination flow shown in FIG. 7 in parallel, it is possible to determine the gripping state, such as normal gripping, abnormal gripping size, gripping failure, or gripping abnormality. As a result, a highly reliable gripping mechanism can be realized. Furthermore, as another example of processing, for example, by monitoring the change over time in the rotor angle (RA) detected in step S701 during the pressing state, it is possible to determine the hardness of the object based on the monitoring results. This will be described below.

[0070] Fig. 8A is a diagram showing an example of the change in rotor angle over time in the motor system according to the second embodiment when the object 207 gripped by the gripping mechanism 104 shown in Fig. 2 is hard. Fig. 8B is a diagram showing an example of the change in rotor angle over time when the gripped object 207 is soft, unlike Fig. 8A. When the object 207 is hard, the rotor angle quickly balances with a certain pressing force. For this reason, as shown in Fig. 8A, the change in rotor angle over time obtained at each relatively long period tends to have a small fluctuation range.

[0071] On the other hand, if the object 207 is soft, the object 207 continues to deform, for example, even after receiving a certain pressing force in a pressing state. As a result, the rotor angle does not immediately balance with the pressing force. Then, for example, after the process shown in FIG. 5 is executed multiple times, the rotor angle also balances when the amount of deformation of the object 207 balances with the pressing force. Therefore, as shown in FIG. 8B, the change over time in the rotor angle acquired at a fairly long period tends to monotonically increase or decrease. In this way, by determining the hardness of the gripping force using part of the flowchart shown in FIG. 7 and adding this to the information for determining the gripping state described in FIG. 7, a more reliable gripping mechanism can be realized.

[0072] <Major Effects of the Second Embodiment> As described above, the method of the second embodiment can also achieve the same effects as those described in the first embodiment. In addition, during a gripping operation, it is possible to determine the size of the object being gripped and the gripping state from the rotor angle detected by the angle sensor and the lead angle calculated from the electrical angle. As a result, it is possible to perform abnormality processing according to the gripping state, enabling highly reliable gripping control. In addition, it is also possible to determine the hardness of the object from the amount of change per unit time in the detected rotor angle.

[0073] (Third embodiment) <Example of application to an automatic analysis system> Figure 9 is a schematic diagram showing an example of the configuration of an automatic analysis system to which a motor system according to a third embodiment is applied. Figure 10 is a schematic diagram showing an example of the configuration of a rack 1 and sample container 3 in Figure 9. The automatic analysis system shown in Figure 9 mainly includes a transport mechanism 2, a stopper opening and closing mechanism 4, a reaction disk 8, a reagent disk 9, a reagent probe 9a, a sample probe 10, a sample information reading mechanism 11, a stopper holding mechanism 12, a stopper identification mechanism 13, a stirrer 16, a sample input unit 21, and a control computer 25.

[0074] A rack 1 containing a plurality of specimen containers 3 is placed in the specimen loading section 21. As shown in FIG. 10 , the plurality of specimen containers 3 are placed in the rack 1 with stoppers 5 attached. The specimen containers 3 contain biological samples such as blood or urine. The specimen containers 3 are cylindrical containers with a diameter of, for example, 13 mm or 16 mm. The stoppers 5 have a cylindrical shape with a diameter larger than the opening of the specimen container 3, and are made of a material such as rubber or plastic.

[0075] Here, the stoppers 5 can have various structures, as shown in Figure 10. Stoppers 5a-5c are attached by press-fitting to the openings of specimen containers 3a-3c, respectively. Stoppers 5d and 5e are attached by screwing to the openings of specimen containers 3d and 3e. On the other hand, when removing the stoppers 5 from the openings of specimen containers 3, the stoppers 5a-5c are removed by, for example, swinging or rotating in the circumferential direction. Stoppers 5d and 5e are removed by rotating using the threaded portions.

[0076] 9 , the transport mechanism 2 transports a rack 1 containing a plurality of specimen containers 3. The cap opening / closing mechanism 4 has a gripping device that grips objects such as specimen containers 3 and caps 5. The cap opening / closing mechanism 4 uses the gripping device to perform an unplugging operation to remove the caps 5 from the specimen containers 3 transported by the transport mechanism 2, and a capping operation to reattach the removed caps 5. The cap holding mechanism 12 is a mechanism that temporarily holds the removed caps 5 and stores and transports the caps 5.

[0077] The reaction disk 8 is rotatable on the XY plane and has multiple reaction containers 8a mounted along its circumference. The specimen probe 10 dispenses biological samples from specimen containers 3 into the reaction containers 8a. The reagent disk 9 is rotatable on the XY plane and has multiple reagent containers 9b mounted along its circumference. The reagent containers 9b contain various reagents used in analysis. The reagent probe 9a dispenses the required reagent from the reagent container 9b into the reaction container 8a. The agitator 16 agitates the biological samples and reagents dispensed into the reaction containers 8a.

[0078] The specimen information reading mechanism 11 and the stopper identification mechanism 13 are installed on the transfer line of the specimen container 3. The specimen information reading mechanism 11 reads specimen information sealed in the specimen container 3, for example, based on labels attached to the specimen container 3 or the rack 1. The stopper identification mechanism 13 identifies the stopper 5. The control computer 25 controls the operation sequence of the entire system based on information obtained by the specimen information reading mechanism 11 and the stopper identification mechanism 13.

[0079] Fig. 11A is a schematic diagram showing an example of the cap opening / closing operation by the cap opening / closing mechanism 4 in Fig. 10. Fig. 11B is a schematic diagram showing an example of the dispensing operation by the sample probe 10 in Fig. 10. Fig. 11C is a schematic diagram showing an example of the cap closing operation by the cap opening / closing mechanism 4 in Fig. 10. More specifically, as shown in Figs. 11A and 11C, the cap opening / closing mechanism 4 has a transfer arm 4a, a cap chuck mechanism 4b, a clamp 4c, and a screw mechanism 4d.

[0080] The transport arm 4a moves the stopper chuck mechanism 4b in three axial directions. The stopper chuck mechanism 4b grips and releases the stopper 5. The clamp 4c grips the sample container 3 and moves it up and down, i.e., in the Z-axis direction. The screw mechanism 4d rotates the gripped stopper 5. At least one set of the stopper chuck mechanism 4b, clamp 4c, and screw mechanism 4d is attached to the transport arm 4a in accordance with the throughput of the automatic analysis system.

[0081] Next, we will briefly explain the main analytical procedures using the automated analysis system. First, a subject or an operator places a biological sample such as blood or urine in a sample container 3 and then seals the sample container 3 with a stopper 5. The operator then places the sample container 3 on the rack 1 and inserts it into the automated analysis system via the sample insertion unit 21.

[0082] The rack 1 is transported by the transport mechanism 2. During this transport process, the specimen information reading mechanism 11 and the stopper identification mechanism 13 read the specimen information and stopper identification information at the specimen information reading position 2a. This allows obtaining information such as the diameter, height, and type of the specimen container 3, as well as type information of various stoppers 5 as shown in FIG. 10 . The specimen container 3 is then transported by the transport mechanism 2 to the stopper opening position 2b.

[0083] Next, the uncap operation will be described using Figure 11A. The specimen container 3 transferred to the uncap position 2b is lifted to the uncap position while being gripped by the clamp 4c of the cap opening / closing mechanism 4 (Figure 11A-(1) and (2)). The cap chuck mechanism 4b grips the cap 5 and removes it from the specimen container 3 (Figure 11A-(2) and (3)). At this time, the cap opening / closing mechanism 4 performs the uncap operation corresponding to the specimen container 3 and cap 5 identified by the specimen information reading mechanism 11 and the cap identification mechanism 13, based on instructions from the control computer 25. The removed cap 5 is then transferred by the transport arm 4a to the cap holding portion 12a of the cap holding mechanism 12 for temporary storage (Figure 11A-(4) and (5)).

[0084] Next, the specimen container 3 is transported to a sample collection position 2c by the transport mechanism 2. Then, at the specimen collection position 2c, a dispensing operation as shown in Fig. 11B is performed. That is, as shown in Fig. 11B, the specimen probe 10 dispenses a fixed amount of specimen from the specimen container 3 transported to the sample collection position 2c into a reaction vessel 8a.

[0085] Thereafter, although not shown, the reagent probe 9a dispenses a fixed amount of reagent from the reagent container 9b placed on the reagent disk 9 into the reaction container 8a. The stirring device 16 stirs the sample and reagent dispensed into the reaction container 8a. After a fixed reaction time has elapsed, the detection optical device 14a measures the absorbance, spectrum, etc. of the reaction container 8a and outputs the measurement results to the control computer 25.

[0086] Next, the specimen container 3 for which measurement has been completed is transported to specimen information reading position 2d by the transport mechanism 2. The control computer 25 identifies the stopper 5 corresponding to the specimen container 3 by reading the specimen information using the specimen information reading mechanism 11. The specimen container 3 is then transported to capping position 2e by the transport mechanism 2. Meanwhile, the cap holding mechanism 12 transports the stopper 5 identified by the control computer 25 to capping position 2e. This completes the capping operation.

[0087] The capping operation will be described using Figure 11C. The clamp 4c of the cap opening / closing mechanism 4 grips and lifts the specimen container 3 that has been transferred to the capping position 2e (Figure 11C-(1)). Meanwhile, the transfer arm 4a transfers the cap 5 gripped by the cap chuck mechanism 4b from the cap holder 12a to the upper concentric axis of the specimen container 3 (Figure 11C-(2)). The cap chuck mechanism 4b attaches the cap 5 to the specimen container 3 through the capping operation (Figures 11C-(3) and 11C-(4)). This attachment may be performed in conjunction with the use of a screw mechanism 4d that grips and rotates the cap 5. The cap chuck mechanism 4b and clamp 4c then release the cap 5 from their grip (Figure 11C-(5)).

[0088] Here, each of the plug chuck mechanism 4b, the clamp 4c, and the screw mechanism 4d also serves as a gripping device. The method described in the first or second embodiment is applied to this gripping device. That is, the plug chuck mechanism 4b or the clamp 4c shown in Figures 11A and 11C corresponds to the grippers 206a and 206b in Figures 2A and 2B. Furthermore, the screw mechanism 4d can be configured, for example, by combining a gripping mechanism with a mechanism for rotating an object using a stepping motor 105, as described in the first embodiment.

[0089] <Example of Application to a Slide-Type Sample Processing System> Fig. 12 is a schematic diagram showing an example of the configuration of a slide-type sample processing system to which the motor system according to the third embodiment is applied. The slide-type sample processing system shown in Fig. 12 includes a staining unit 60, a slide glass input unit 61, a slide glass storage unit 62, a sampler unit 63, a slide glass input line 64, a slide glass storage line 65, and a slide glass transport device 70.

[0090] The staining unit 60 has the function of staining a sample placed on a slide glass. Here, two staining units 60A and 60B are shown as the staining unit 60. The slide glass on which the sample to be stained is placed is placed in a slide glass input section 61. Furthermore, the slide glass on which the sample stained by the staining unit 60 is placed is stored in a slide glass storage section 62. Here, the sampler unit 63 is configured as a unit including the slide glass input section 61 and the slide glass storage section 62.

[0091] The slide glass input line 64 transfers slide glasses carrying samples to be stained from the slide glass input section 61 to the staining unit 60. Meanwhile, the slide glass storage line 65 transfers slide glasses carrying stained samples from the staining unit 60 to the slide glass storage section 62. The sampler unit 63 and the staining unit 60 each have a slide glass transport device 70. Specifically, the sampler unit 63 has a slide glass transport device 70A. The staining units 60A and 60B have slide glass transport devices 70B and 70C, respectively.

[0092] Furthermore, a stage 80 for placing slides is provided in each of the staining unit 60, the slide glass input section 61, the slide glass storage section 62, the slide glass input line 64, and the slide glass storage line 65. The stage 80 includes a tray for placing the slides, a carrier for placing the slides and moving them within the apparatus, and a processing table for placing the slides and performing pre-processing such as deparaffinization and staining.

[0093] Specifically, the slide glass input section 61 is provided with a plurality of stages 80A. The slide glass storage section 62 is provided with a plurality of stages 80B. The slide glass input line 64 is provided with a stage 80C. The staining unit 60A is provided with a plurality of stages 80D. The staining unit 60B is provided with a plurality of stages 80E. The slide glass storage line 65 is provided with a stage 80F.

[0094] Next, a brief description of the operation of the slide-type sample processing system will be given. First, the slide transport device 70A transports a slide placed on a stage 80A provided in the slide input section 61 to a stage 80C provided in the slide input line 64. At this time, the transported slide carries a sample to be stained.

[0095] Next, the slide glass input line 64 transports the stage 80C on which the slide glass is placed to load the slide glass into the staining unit 60A or the staining unit 60B. When loading the slide glass into the staining unit 60A, the slide glass transporting device 70B transports the slide glass from the stage 80C to the stage 80D in the staining unit 60A. On the other hand, when loading the slide glass into the staining unit 60B, the slide glass transporting device 70C transports the slide glass from the stage 80C to the stage 80E in the staining unit 60B.

[0096] When a slide glass is loaded into the staining unit 60A, the sample on the slide glass placed on the stage 80D is stained in the staining unit 60A. On the other hand, when a slide glass is loaded into the staining unit 60B, the sample on the slide glass placed on the stage 80E is stained in the staining unit 60B.

[0097] Thereafter, the slide glass carrying the sample stained in the staining unit 60A is transported by the slide glass transporting device 70B from the stage 80D to the stage 80F provided in the slide glass storage line 65. Meanwhile, the slide glass carrying the sample stained in the staining unit 60B is transported by the slide glass transporting device 70C from the stage 80E to the stage 80F provided in the slide glass storage line 65.

[0098] Then, the slide glass storage line 65 transports the stage 80F on which the slide glass is placed to the slide glass storage unit 62. Thereafter, the slide glass transporting device 70A transports the slide glass from the stage 80F to the stage 80B provided in the slide glass storage unit 62.

[0099] As described above, the slide-type sample processing system generally performs staining processing on a sample placed on a slide removed from slide input section 61 using staining units 60A and 60B, and then stores the slide on which the stained sample is placed in slide storage section 62. Note that while an example configuration including staining units 60A and 60B has been shown here, the system may also include a coverslip mounting unit, a slide imaging unit, and the like.

[0100] <Slide Glass Transporting Device> Figure 13 is a perspective view showing a schematic configuration example of the slide glass transporting device 70 in Figure 12. The slide glass transporting device 70 shown in Figure 13 includes a gripping unit 71 that grips a slide glass and a driving unit 72. The slide glass 81 is placed on a stage 80. The driving unit 72 is configured to transport the gripping unit 71 in the horizontal direction and the up-down direction using a Z transport shaft 72a, an X transport shaft 72b, and a Y transport shaft 72c. The transport operation of the gripping unit 71 by the driving unit 72 is controlled by a controller (not shown).

[0101] The gripping unit 71 has at least two fingers 83 for gripping the slide glass 81 and a finger drive unit 71a for moving these fingers 83. The finger drive unit 71a is used to open and close the fingers 83, thereby gripping and releasing the slide glass 81. The method described in the first or second embodiment is applied to this gripping unit 71, i.e., the gripping device.

[0102] Fig. 14 is a schematic diagram showing an example of the configuration of the fingers 83 in Fig. 13. As shown in Fig. 14, the slide glass 81 is supported and gripped by fingers 83A and 83B. The slide glass 81 has a size of, for example, 25 mm x 75 mm. In this case, the width of the slide glass 81 shown in Fig. 14 is 75 mm.

[0103] The finger 83A is configured to include a support portion 84A and a pointed portion 85A. When supporting and gripping the slide 81, the support portion 84A supports a portion of the underside of the slide 81. Meanwhile, the pointed portion 85A contacts a gripping point 86a on one side of the slide 81 that is located below the top surface of the slide 81. Similarly, the finger 83B is configured to include a support portion 84B and a pointed portion 85B. When supporting and gripping the slide 81, the support portion 84B supports a portion of the underside of the slide 81. Meanwhile, the pointed portion 85B contacts a gripping point 86b on the other side of the slide 81 that is located below the top surface of the slide 81.

[0104] In this manner, the slide glass 81 is supported and gripped by the pair of fingers 83A and 83B. Specifically, the slide glass 81 is supported by the supports 84A and 84B and gripped by the pointed heads 85A and 85B. The pair of fingers 83A and 83B corresponds to, for example, the grippers 206a and 206b in Figures 2A and 2B.

[0105] 15A and 15B are schematic diagrams showing an example of the configuration of a gripping device serving as a comparative example in the automatic analysis system shown in Fig. 9 or the slide-type sample processing system shown in Fig. 12. Here, the example is a case where the object to be gripped is the specimen container 3 shown in Fig. 11A etc. When a stepping motor is used as the actuator of the gripping mechanism and the object is gripped under open-loop control, a gripping device, i.e., a gripping mechanism such as that shown in Fig. 15A and 15B is generally used.

[0106] 15A and 15B , a stepping motor 903 is connected to a ball screw 901 inserted into a nut 902. The nut 902 moves on the ball screw 901 in accordance with the rotation of the stepping motor 903. The nut 902 comes into contact with a gripper 905, thereby moving the gripper 905 on a linear guide 904.

[0107] The pair of grippers 905 are connected to each other by a spring 906. As shown in Fig. 15A, when the nut 902 is moved to the right, the gripper 905 performs an opening operation while stretching the spring 906. On the other hand, as shown in Fig. 15B, when the nut 902 is moved to the left, the gripper 905 performs a closing operation by utilizing the restoring force of the spring 906. In the process, the gripper 905 comes into contact with the object 907 and grips the object 907.

[0108] However, with this method, the gripping force when the gripping mechanism grips the object 907 is uniquely determined by the restoring force generated in the spring 906 based on Hooke's law given by equation (3.1). F = kx ... (3.1) F: restoring force of the spring k: spring constant x: displacement (extension or contraction) from the free length of the spring

[0109] Therefore, when gripping sample containers 3 of different sizes (diameters), for example, 13 mm and 16 mm, the displacement x from the free length of the spring becomes indefinite according to formula (3.1), and as a result, the gripping force becomes inconstant. Specifically, for example, a thicker sample container 3 has a larger displacement x from the free length of the spring than a thinner one, and therefore the gripping force becomes larger according to formula (3.1).

[0110] 15A and 15B, unless a detection means such as an external object detection sensor is added, it is difficult to measure the size (diameter) of the specimen container 3, which is the object 907. It is also difficult to determine the gripping state, such as when the object 907 is not gripped correctly or when gripping has failed.

[0111] On the other hand, when the method of the embodiment is used, pressing control associated with gripping is performed according to the flowcharts shown in Figures 4 and 5, making it possible to grip the specimen container 3 with a constant gripping force regardless of the size (diameter) of the specimen container 3. Furthermore, by using the flowchart shown in Figure 7, it is possible to determine the gripping state, such as whether the specimen container 3 is being gripped correctly. In particular, in step S704 shown in Figure 7, when the specimen container 3 is being gripped correctly, it is possible to determine the size (diameter) of the gripped specimen container 3 by determining the magnitude of the rotor angle (RA) detected by the angle sensor 106.

[0112] In this way, by determining the size (diameter) of the specimen container 3 in the gripping mechanism of the automated analysis system, it is possible to determine whether the specimen container 3 that has been introduced is of a size (diameter) compatible with the system before analyzing the biological sample. For example, the size of the specimen container 3 can be determined during the uncapping operation shown in Figure 11A. Furthermore, from the obtained diameter information, it is possible to determine in advance the effective specimen volume in the specimen container 3.

[0113] Furthermore, by being able to determine the size (diameter) of the specimen container 3, it is possible to determine whether the specimen container 3 has been mixed up for some reason during the process. For example, during the uncap operation shown in Fig. 11A or the capping operation shown in Fig. 11C, it is possible to detect a case in which the container size based on the specimen information read by the specimen information reading mechanism 11 differs from the container size determined based on the rotor angle. These features make it possible to build a highly reliable automatic analysis system.

[0114] Furthermore, the same effect can be obtained not only when gripping specimen containers 3 used in an automated analysis system, but also when gripping glass slides 81 used in a slide-type sample processing system. That is, regardless of the size of the glass slide 81, it is possible to grip the glass slide 81 with a constant gripping force within a range that will not cause breakage. The size of the glass slide 81 can also be detected in a similar manner. Therefore, it is possible to determine whether the inserted glass slide 81 is a size compatible with the system, whether the glass slide 81 has not been broken for some reason during the process, or whether the slide 81 has not been mixed up. As a result, a highly reliable slide-type sample processing system can be constructed.

[0115] <Major Effects of the Third Embodiment> As described above, by using the method of the third embodiment, it is possible to obtain the same effects as those described in the first and second embodiments. In addition, it is possible to construct a highly reliable automatic analysis system or slide-type sample processing system.

[0116] The invention made by the inventor has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments and can be modified in various ways without departing from the spirit of the invention. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0117] 3: specimen container, 81: slide glass, 101: controller, 102: driver circuit, 103: angle sensor detection circuit, 104: gripping mechanism, 105: stepping motor, 106: angle sensor, 201: retainer, 202: ball screw, 203: nut, 206a, 206b: gripper, 207: object, 301: stator, 302: rotor, 303: A-phase coil, 304: B-phase coil, 305: rotor angle, 306: electrical angle

Claims

1. A motor system comprising: a stepping motor having a rotor, a stator, and a coil attached to the stator, and applying force to an object via a power transmission mechanism; an angle sensor that detects the rotor angle of the rotor; a driver circuit that can control the magnetic field vector created by the stator to any electrical angle and can control the value of the current flowing through the coil to a constant value; and a controller that inputs the rotor angle from the angle sensor and performs feedback control on the stepping motor via the driver circuit, wherein the controller controls the stepping motor so that, when applying force to the object, the lead angle, which is the difference between the electrical angle of the magnetic field vector and the rotor angle, maintains a constant set lead angle.

2. A motor system according to claim 1, wherein the power transmission mechanism is a gripping mechanism that grips the object by moving a gripper, the stepping motor moves the gripper to cause the gripping mechanism to grip the object, and the controller controls the stepping motor so that the lead angle maintains the set lead angle while the gripping mechanism is gripping the object.

3. A motor system according to claim 2, wherein the controller determines whether the gripper has come into contact with the object depending on whether the advance angle has reached the set advance angle.

4. A motor system according to claim 3, wherein the controller detects the size of the object based on the rotor angle detected after the gripper comes into contact with the object.

5. A motor system according to claim 3, wherein the controller determines that gripping has failed when the advance angle becomes 0 degrees after the gripper has come into contact with the object.

6. A motor system according to claim 3, wherein the controller monitors changes over time in the rotor angle obtained while the advance angle is maintained at the set advance angle after the gripper has come into contact with the object, and determines the hardness of the object based on the changes over time in the rotor angle.

7. A motor system according to claim 1, wherein the controller and the driver circuit have a configuration compatible with a microstep drive system.

8. A motor system according to claim 1, wherein the controller controls the force applied to the object by controlling the value of the current flowing through the coil of the stepping motor while maintaining the lead angle at the set lead angle.

9. The motor system according to claim 8, wherein the controller controls the pressing force applied to the object.

10. The motor system according to claim 8, wherein the controller controls the rotational force applied to the object.

11. A gripping device for gripping an object, comprising: a gripping mechanism for gripping the object; a stepping motor having a rotor, a stator, and a coil attached to the stator, and transmitting power to the gripping mechanism to cause the gripping mechanism to grip the object; an angle sensor for detecting a rotor angle of the rotor; a driver circuit that is capable of controlling a magnetic field vector generated by the stator to an arbitrary electrical angle and of controlling the value of current flowing through the coil to a constant value; and a controller that inputs the rotor angle from the angle sensor and performs feedback control on the stepping motor via the driver circuit, wherein when causing the gripping mechanism to grip the object using the stepping motor, the controller controls the stepping motor so that a lead angle, which is the difference between the electrical angle of the magnetic field vector and the rotor angle, is maintained at a constant set lead angle.

12. A gripping device according to claim 11, wherein the controller determines whether the gripping mechanism has gripped the object based on whether the advance angle has reached the set advance angle.

13. A gripping device according to claim 12, wherein the controller detects the size of the object based on the rotor angle detected after the gripping mechanism has gripped the object.

14. A gripping device according to claim 11, wherein the object is a specimen container containing a biological sample.

15. A gripping device according to claim 11, wherein the object is a slide glass on which a sample is placed.

Images