Control system for magnetic levitation device

Abstract

To provide a control system for a magnetic levitation device capable of easily and suitably achieving zero power control.SOLUTION: A control system of a magnetic levitation device includes a magnet unit with an electromagnet and a permanent magnet, a current control device 7 for inputting an excitation current to the electromagnet, and a control device 9 for inputting a command value i* of a current value i in the current control device 7, supports a levitated object by magnetic force of the magnet unit, and controls a position of the levitated object. The control system includes a position servo 13 that outputs the command value i* of the current value i with a position command x* of the levitated object as an input value, performs state feedback control in which a detected position x of the levitated object is fed back to the position servo 13 and a state quantity of the levitated object is fed back to downstream of the position servo 13, and further performs feedback of the command value i* of the current value i input to the current control device 7 to the position servo 13 as a current feedback signal 14.SELECTED DRAWING: Figure 10

Description

Technical Field

[0001] The present invention relates to a system for controlling the position of an object in a device that levitates the object using electromagnetic force.

Background Art

[0002] A magnetic levitation device is a technology that supports an object without contact by magnetic force. In a magnetic levitation device, when supporting an object (hereinafter referred to as a "levitated body" in this specification), there is a characteristic that no mechanical contact is required between the mechanism on the supporting side and the levitated body side to be supported, and many advantages resulting therefrom (such as no wear due to friction, no frictional heat, no noise, and no need for a lubricant). For example, its use in various devices such as belt conveyors, flywheels, and linear motor cars has been proposed and put into practical use.

[0003] Such a magnetic levitation device is configured by combining a permanent magnet and an electromagnet, and supports the levitated body by the magnetic forces of the permanent magnet and the electromagnet. If the total value of the magnetic forces balances the weight of the levitated body, the levitated body can be supported.

[0004] Here, since the total value of the magnetic forces depends not only on the exciting current flowing through the electromagnet but also on the distances between the electromagnet, the permanent magnet, and the object, if the position of the levitated body is adjusted to a position where the gravity acting on the levitated body and the magnetic force by the permanent magnet are balanced, it is possible to support the levitated body while setting the current flowing through the electromagnet to zero amperes. This is called zero-power control.

[0005] The position of the floating body at which zero-power control is possible varies depending on the weight of the floating body, and the weight of the floating body can vary according to the load to be loaded, the components to be mounted, etc. Also, during the support of the floating body, the position of the floating body may vary due to external forces such as vibration. Therefore, when performing zero-power control in a magnetic levitation device, when there is a deviation between the position at which zero-power control is possible (hereinafter, in this specification, the "position of the floating body at which zero-power control is possible" will be conveniently referred to as the "zero control position") and the actual position of the floating body, a current is passed through the electromagnet to adjust the total magnetic force with the permanent magnet, and thereby control is performed to move the position of the floating body closer to the zero control position. During this time, it is necessary to temporarily pass a current through the electromagnet, but if the position of the floating body stabilizes at the zero control position, the current value converges to zero, and zero-power control becomes possible again.

[0006] As prior art documents related to this type of magnetic levitation device and its control, for example, there are the following Patent Document 1, Non-Patent Documents 1, 2, etc.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Documents

[0008]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] Regarding zero-power control in a magnetic levitation device, conventionally, as described in, for example, Non-Patent Document 1 above, the position of the levitating body is monitored by a gap sensor, PD control is performed on the signal of the gap sensor, and while multiplying a gain by the current signal corresponding to the control input, integration is performed and positive feedback is applied. Such a method has often been used. However, in such a method, since the adjustment parameters for current control are limited, the adjustment is easy, but there are limitations in the performance of controlling the position of the levitating body and zero-current control, and in particular, the transient characteristics have weaknesses.

[0010] As a method capable of improving such weaknesses, for example, there is a method of using current servo type state feedback control as described in Non-Patent Document 2 above. All state quantities of the control object are fed back, and the measurement loop is a servo system with an integrator by a current signal. According to such a control method, while improving the dynamic characteristics, it is possible to arbitrarily control the current value. If the current command value is set to zero, zero-power control can be realized, and the transient characteristics until reaching zero current are also improved. However, this method also has some problems. For example, since it is voltage input type control instead of current input type, there is a drawback that state feedback control cannot be performed as it is.

[0011] In order to convert the control to the current input type and perform state feedback control, for example, a method of adding pseudo-current characteristics to the voltage value as the control input can be considered. However, problems such as an increase in the calculation load and the need for further adjustment of the time constant for the added current characteristics occur. Regarding the design and adjustment of the poles, in the method of Non-Patent Document 1, the design of the PD gain and the zero-power gain is sufficient. However, in the method of Non-Patent Document 2, since adjustment of pseudo-parameters different from such physical parameters is required, it is necessary to determine by trial and error how to set the poles in the actual machine experiment and how to proceed with the experiment (especially in the case of magnetic levitation control, it is necessary to design from the viewpoint that if the poles are made large negatively, the current will become small, which is the opposite of normal motor control), which is very laborious and time-consuming. In addition, in the method of Non-Patent Document 2, there are also problems such as the inability to design the characteristics of position control and zero-power control individually and the inability to switch between position control and zero-power control.

[0012] In view of such circumstances, the present invention aims to provide a control system for a magnetic levitation device that can simply and suitably realize zero-power control.

Means for Solving the Problems

[0013] The present invention provides a control system for a magnetic levitation device including a magnet unit having an electromagnet and a permanent magnet, a current control device for inputting an excitation current to the electromagnet, and a control device for inputting a command value of a current value to the current control device. The levitating body is supported by the magnetic force of the magnet unit, and the control system for the magnetic levitation device controls the position of the levitating body. The control system is characterized in that it includes a position servo that outputs a command value of a current value using the position command of the levitating body as an input value, feeds back the detected position of the levitating body to the position servo, and performs state feedback control for feeding back the state quantity of the levitating body downstream of the position servo. Further, it is configured such that at least one of the current value output from the current control device or the command value of the current value input to the current control device can be further fed back to the position servo as a current feedback signal.

[0014] The control system of the magnetic levitation device of the present invention can be configured to feedback the command value of the current value input to the current control device to the position servo as the current feedback signal.

[0015] The control system of the magnetic levitation device of the present invention can be configured to be able to switch the on / off of the current feedback signal.

Effect of the Invention

[0016] According to the control system of the magnetic levitation device of the present invention, it is possible to achieve an excellent effect of simply and suitably realizing zero-power control.

Brief Description of the Drawings

[0017]

Figure 1

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Figure 12

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0019] FIG. 1 shows an example of the form of a magnetic levitation device as a control target in a control system of a magnetic levitation device. For simplicity, FIG. 1 schematically shows a simplified example of the configuration of the magnetic levitation device.

[0020] In the magnetic levitation device of FIG. 1, a carrier 3 provided with a magnet unit 2 is disposed below a support (guide rail) 1 made of a magnetic material such as iron. A load 4 is loaded on the carrier 3, and the entire carrier 3 provided with the magnet unit 2 and loaded with the load 4 is supported with respect to the guide rail 1 by the magnetic force generated between the magnet unit 2 and the guide rail 1. The carrier 3 provided with the magnet unit 2 and the load 4 loaded thereon are levitating bodies, and the weight (mg) of the entire levitating body is supported by the upward guide rail 1 by the attractive force due to the magnetic force.

[0021] The magnet unit 2 includes a permanent magnet 5 and an electromagnet 6. The permanent magnet 5 generates a magnetic force corresponding to the distance from the guide rail 1 between it and the guide rail 1. Also, a current control device 7 for generating an exciting current is connected to the electromagnet 6, and the current input from the current control device 7 and the magnetic force corresponding to the distance from the guide rail 1 are generated between the electromagnet 6 and the guide rail 1. The carrier 3 is further equipped with a gap sensor 8 so that the distance from the guide rail 1 is detected as a position signal.

[0022] The on / off of the current control device 7 and the current value flowing through the electromagnet 6 are controlled by a control device 9. The control device 9 is an information processing device that monitors the states of each part constituting the magnetic levitation device and controls the operation. A position signal is input from the gap sensor 8 to the control device 9. Also, a current sensor 10 is provided in the circuit between the current control device 7 and the control device 9, and the current value detected by the current sensor 10 is also input to the control device 9 as a current signal. The control device 9 operates the current control device 7 based on these signals and the like.

[0023] Note that the configuration of the magnetic levitation device shown here is merely an example, and various configurations other than those described here are conceivable for the magnetic levitation device to which the present invention is applied. For example, the levitating body may be disposed above the support and the levitating body may be supported by a repulsive force instead of an attractive force, or all or part of the magnet unit may be provided on the support side instead of the levitating body side.

[0024] Consider the position control of the floating body performed in the magnetic levitation device as described above.

[0025] First, in the magnetic levitation device as shown in Fig. 1, the equation of motion in the vertical direction in a state where the magnetic force (attractive force) by the permanent magnet and the gravity acting on the floating body are in balance is expressed as follows in Equation (1).

Equation

[0026] However, m is the mass of the entire floating body [kg], x is the vertical displacement [m] between the floating bodies, F is the attractive force of the electromagnet [N], i is the coil current flowing through the electromagnet [A], k s is the characteristic coefficient of the electromagnet [N / m] representing the relationship between the displacement and the attractive force, k i is the characteristic coefficient of the electromagnet [N / m] representing the relationship between the current value and the attractive force, and d represents the external force [N] acting on the floating body as a disturbance.

[0027] The equation of motion of Equation (1) can be converted into the state equation of Equation (2), and further, the state equation can be expressed in matrix form as Equation (3).

Equation

Equation

[0028] Fig. 2 shows the input and output in such a control object 100 in a block diagram. The attractive force F by the electromagnet is the value obtained by multiplying the current value i by the characteristic coefficient k i and the value obtained by multiplying the displacement x by the characteristic coefficient k sIt is obtained as the sum of the values multiplied by (see Equation 1 above). The value obtained by adding the external force d to this is the total force applied to the floating body with mass m, and the value obtained by dividing this value by the mass m is the acceleration. The value obtained by integrating the acceleration corresponds to the velocity v, and the value obtained by further integrating the velocity v corresponds to the displacement x. The current value i and the displacement x are grasped as the current signal of the current sensor 10 and the position signal of the gap sensor 8 in FIG. 1, respectively. Regarding the term "displacement", in this specification, it is used without particularly distinguishing it from the term "position", but these terms "displacement" and "position" have no difference from each other in the sense of "the value represented by the letter x in the above equations and the control described in this specification".

[0029] For the control object 100 as described above, first, consider a control that combines state feedback and current control. FIG. 3 shows an example of such a control method as a first reference example, reproducing a pseudo-coil characteristic (displayed as a pseudo-coil 11 in the figure) in the control device 9 and providing a current servo 12 on its upstream side. The current servo 12 outputs a voltage value V in response to the input of the current command i * . The voltage value V is input to the pseudo-coil 11, and the pseudo-coil 11 outputs a current i corresponding to the voltage value V, which is input to the control object 100. The output current value i is fed back to the pseudo-coil 11. Also, from the control object 100, the velocity v and the displacement x are fed back to the pseudo-coil 11 as state quantities, and based on these feedback values and the current command i * input from the current servo, the voltage V is input to the pseudo-coil 11. Here, the value of the velocity v is obtained by approximately differentiating the displacement x. When feeding back the current value i, the velocity v, and the displacement x to the pseudo-coil 11, experimentally determined gains f i , f v , f x are respectively multiplied and negatively fed back.

[0030] The results of simulating the response of the control target 100 by the control method of the first reference example are shown in Fig. 4. In Fig. 4, (A) shows the displacement x, and (B) shows the behavior of the current value i. The control system has been executing zero-power control since the start time t0. From this state, an external force d is applied to the control target 100 as a disturbance at time t1, and then the external force d is removed at time t3.

[0031] After the external force d is applied at time t1, displacement occurs (see Fig. 4(A)), and accordingly, an exciting current is generated (see Fig. 4(B)). It can be seen that the current value converges to zero by time t2. Regarding the position, due to the application of the external force, the position after t2 is shifted in the positive direction from the position before t1 (see the arrow in Fig. 4(A)). That is, when the external force is applied at time t1, the zero-control position shifts from the previous one. After that, an exciting current is applied to the electromagnet 6, and the position of the floating body converges to a new zero-control position by the electromagnetic force. Zero-power control is performed at the new zero-control position after time t2. Further, when the external force d is removed at time t3, an exciting current is generated again from time t4, the floating body is returned to the original zero-control position, and zero-power control is performed again after time t4.

[0032] Thus, in the control method of Fig. 3, state feedback control is performed by the input of the current command i * and zero-power control is also possible. On the other hand, there are problems such as an increase in the calculation load due to the calculation of the pseudo-coil characteristics and the time-consuming design and adjustment of the poles. Therefore, next, a control method using the position instead of the current value as the control input will be considered.

[0033] Fig. 5 is a block diagram showing an example of such position control type state feedback control as the second reference example. The position servo 13 provided in the control device outputs a current command i * in response to the input of the position command x * The current command i *is input into a current control device (corresponding to the current control device 7 in FIG. 1), and from here, the current i is input into the control object 100. From the control object 100, the displacement x (the position of the floating body detected by the gap sensor 8 in FIG. 1) and the velocity v obtained by approximately differentiating it are fed back downstream of the position servo 13, and the current command i corresponding to these feedback values * is input into the current control device 7 again. When feeding back the velocity v and the displacement x to the dummy coil 11, the experimentally determined gains f v and f x are multiplied respectively and then negatively fed back.

[0034] Also, in this second reference example, the value of the displacement x is negatively fed back to the position servo 13, and a closed loop is formed as a whole by the input of the position command and the output of the position signal.

[0035] The results of the simulation regarding the response of the control object 100 in such a control method are shown in FIG. 6. Among the graphs shown in FIG. 6, (A) shows the displacement x and (B) shows the behavior of the current value i. Similar to FIG. 4 above, the control system is performing zero-power control from the start time t0, and from that state, an external force d is applied to the control object 100 as a disturbance at the time t1, and then the external force d is removed at the time t3.

[0036] In the initial state (time t0 to t1) where the floating body is at the zero control position and the magnetic force of the permanent magnet and gravity are balanced, zero-power control is realized, and both the displacement and the current value are zero. When an external force d is applied as a disturbance at time t1, a displacement occurs temporarily. In the control system, from here until time t5, a current is input to make the displacement zero, and the displacement converges to zero again.

[0037] However, after time t5, while an external force is applied and the zero control position fluctuates, the position of the floating body is adjusted to the original position (displacement x = 0). Therefore, the electromagnetic force generated by the electromagnet balances the external force, and a corresponding current is generated. That is, in the case of the control method shown in Fig. 5, even if the zero control position is shifted by an external force, the purpose of the control is to keep the floating body at the original position. Therefore, it does not become zero-power control. After that, when the external force is removed at time t3, the current value is adjusted again, and both the displacement x and the current value i converge to zero (from time t6 onwards).

[0038] Regarding the response to such disturbances, comparing the first reference example shown in Figs. 3 and 4 with the second reference example shown in Figs. 5 and 6, after an external force is applied at time t1, in the first reference example (Fig. 4), the position of the controlled object moves to a new zero control position and the current value converges to zero. However, in the second reference example (Fig. 6), the position of the controlled object is controlled to remain unchanged, and the current value does not become zero. On the other hand, regarding the responsiveness after changes in the external force at times t1 and t3, the second reference example (Fig. 6) is superior. The time until the displacement x and the current value i converge is shorter in Fig. 6, and the value of the compensation current at that time (the current value generated until the displacement x converges) is also smaller. Therefore, in order to achieve both responsiveness to fluctuations and zero-power control, a combination of position control type state feedback control and zero-power control is attempted.

[0039] An example of such a control method is shown as a third reference example in Fig. 7. The overall configuration is almost the same as that of the second reference example shown in Fig. 5, but the difference is that the command value i * of the current value is fed back downstream of the position servo 13 and applied together with the feedback values of the speed v and displacement x of the controlled object 100 (hereinafter, the signal related to this feedback is referred to as the current feedback signal 14). The command value i *The feedback is similar to the feedback of the current value i in the first reference example shown in FIG. 3, but the feedback of the current value i in FIG. 3 was negative feedback, while the feedback of the current feedback signal 14 in FIG. 7 is performed as positive feedback, and during feedback, the integrator multiplies by the experimentally determined gain f i / s, which is different. Also, regarding this current feedback signal 14, it can be switched on and off. That is, if the gain f i / s is set to zero, the signal value becomes zero and the feedback is turned off.

[0040] Incidentally, as the current feedback signal 14, for example, instead of the command value i * , the current value i on the downstream side of the current control device 7 can be fed back, or both the current value i and the command value i * can be fed back. Theoretically, it is also possible, but if the command value i * is used as the current feedback signal 14 instead of the current value i, it is not necessary to detect the current on the downstream side of the current control device 7 (that is, for example, in FIG. 1, it is not necessary to use the current sensor 10 for the feedback of the current feedback signal 14).

[0041] The responses of the control system in FIG. 7 are shown in FIGS. 8 and 9. FIG. 8 shows the response when the feedback of the current feedback signal 14 is turned off in the system of FIG. 7, where (A) shows the displacement x and (B) shows the behavior of the current value i. A position command of x = -1 [mm] is input to the position servo 13 at time t0, and then an external force d is applied to the control object 100 at time t7.

[0042] Before time t0 (not shown), zero-power control was being performed at displacement x = 0. When a position command was input at time t0, an excitation current was input, causing a displacement in the control object 100, and it converged to the position where displacement x = -1 and stabilized there. Since this position is deviated from the zero-control position, a current is flowing through the control object 100 in the state of being stable at displacement x = -1. When an external force is applied at time t7, the control object 100 is temporarily displaced from the position of displacement x = -1, but an excitation current for supporting the control object 100 at the position of displacement x = -1 is further supplied from the current control device 7 to resist this, and the control object 100 returns to displacement x = -1 again and stabilizes. The current value i further increases compared to before time t7 by the amount of the applied external force.

[0043] Figure 9 shows the behaviors of displacement x (A) and current value i (B) when the current feedback signal 14 is turned on in the middle (time t8) in the simulation under such conditions. However, even when the feedback by the current feedback signal 14 is turned on, these behaviors hardly change compared to the case when it is off (Figure 8). In the control method of Figure 7, a feedback loop of the current value i is set in the feedback loop for controlling the position (displacement x). However, even when the inner feedback loop is turned on, the control of the position by the outer loop is prioritized, and zero control cannot be realized.

[0044] Therefore, an example of the configuration of a control system obtained by further modifying the control method of Figure 7 is shown as an embodiment of the present invention in Figure 10. The overall configuration is almost the same as that of the third reference example shown in Figure 7, but the command value i of the current value * (current feedback signal 14) is fed back upstream instead of downstream of the position servo 13. Note that this feedback is positive feedback as in the example of Figure 7. That is, in the embodiment of Figure 10, the position command x of the floating body * is used as the input value for the command value i of the current value *It is provided with a position servo 13 that outputs, and while feeding back the displacement x of the floating body output from the control target 100 to the position servo 13, on the downstream side of the position servo 13, the speed v and displacement x obtained as state quantities of the control target 100 are multiplied by gains f v , f x respectively, and then negatively fed back to input a command value i * of the current value again into the control target 100 to perform state feedback. In the configuration thus made, it is the same as the third reference example in FIG. 7, but an integration device feeds back a current feedback signal 14 multiplied by a gain f i / s to the upstream side of the position servo 13, which is the characteristic point.

[0045] In the control system of this FIG. 10, an example of the response when the current feedback signal 14 is turned on is shown in FIG. 11. (A) shows the displacement x, and (B) shows the behavior of the current value i. Similar to FIG. 8, a position command of x = -1 [mm] is input to the position servo 13 at time t0, and an external force d is applied to the control target 100 at time t7.

[0046] Immediately after time t0, the position of the control target 100 tries to move to x = -1 according to the position command to the position servo 13, and an exciting current is also generated for that purpose. However, immediately after that, since the command value i * of the current value is positively fed back from the downstream of the position servo 13, the position command first input from the upstream side is invalidated, and control such that the current value becomes zero, that is, zero-power control, starts. Regardless of the position command of x = -1 input to the position servo 13, the position of the control target 100 converges to the zero control position (x = 0). When the external force d is input at time t7, a temporary movement of the control target 100 and the accompanying current occur, and the position of the control target 100 moves to the zero control position in the presence of the external force d and stabilizes (refer to the arrow in FIG. 11(A)). Note that when the feedback of the command value i * of the current value is turned off, the behavior of the control target 100 becomes the same as in FIG. 8.

[0047] As described above, in the control system shown in FIG. 10, it has been shown that zero control can be achieved by combining position servo type state feedback control with feedback of the command value of the current value. The responsiveness of the control system of this embodiment will be compared with that of the first reference example shown in FIG. 3.

[0048] FIG. 12 is a graph showing the results of simulations regarding the response of the controlled object 100 during zero power control for the first reference example (FIG. 3) and the embodiment (FIG. 10). (A) and (B) show the behavior of the displacement x and the current value i of the controlled object 100 in the first reference example, and (C) and (D) show the behavior of the displacement x and the current value i of the controlled object 100 in the embodiment. In any case, an external force d was applied at time t9 to the point where zero power control was being executed after time t0. As a result, in both the first reference example and the embodiment, after time t9, the current i converges to zero again through a transient response, and the displacement x converges to a new zero control position. However, the performance in the transient response is significantly different. In the embodiment, compared with the first reference example, the time until convergence is much shorter, and the current value in the transient response is also much smaller.

[0049] As described above, in the control system of the embodiment shown in FIG. 10, position servo type state feedback control is applied to a magnetic levitation system using current or a current command as a control input, and further positive feedback of the current value is added to the position servo 13, thereby significantly improving the control performance of the levitated body while realizing zero power control. When the position of the levitated body deviates from the zero control position, until the current becomes zero, the current feedback signal 14 acts as a command by positive feedback, so that despite the presence of an integrator in the position servo 13, due to the effect of stabilizing (converging to zero) the state quantity of the state feedback downstream thereof, zero current control can be performed with high responsiveness. In FIG. 10, the command value i * (command value input to the current control device 7) is fed back to the position servo 13 as an example, but the command value i *Even if the current value i (the value of the current supplied from the current control device 7) is fed back to the position servo 13 instead, it is considered that the same control is theoretically possible.

[0050] In the conventional control method, for example, as in the first reference example shown in FIG. 3, even if zero-power control is possible, there are limitations in the performance of transient characteristics, or as in the second reference example shown in FIG. 5, there are problems such that although transient characteristics can be improved, position control and zero-power control cannot be designed individually. The control system of this embodiment shown in FIG. 10 is configured to add zero-power control by positive feedback of the integrated current to the position servo type state feedback control, thereby realizing the coexistence of high-response transient characteristics and zero-power control as described above. Here, if the feedback of the current value is simply turned off, the control method switches to the position servo type state feedback, so that position control and zero-power control can be easily selected and switched. That is, when the position of the floating body is within a predetermined range including the zero control position, the current feedback signal 14 is turned on to perform zero-power control, and when it exceeds the predetermined range, the current feedback signal 14 is turned off to switch to position control, and it is possible to perform control to move the floating body within the predetermined range or to the zero control position.

[0051] In terms of the system configuration, the design of the system for performing position control and the design of the system for performing zero-power control are each clear, and each can be easily designed. Since the bandwidth of the current control loop related to zero-power control and the pole placement of the state feedback control can be designed individually, the assembly of the experimental procedures required for the design and the outlook for implementation can be simplified. Also, since it is a current input type system, a general-purpose current amplifier can be used, and when the command value i * instead of the current value i is fed back to the position servo 13 as the current feedback signal 14, current detection can also be made unnecessary.

[0052] As described above, the control system of the magnetic levitation device of the present embodiment includes a magnet unit 2 including an electromagnet 6 and a permanent magnet 5, a current control device 7 that inputs an excitation current to the electromagnet 6, and a command value i of a current value i to the current control device 7 * A control device 9 for inputting is provided, and it is a control system of a magnetic levitation device that supports a floating body by the magnetic force of the magnet unit 2 and controls the position of the floating body. The position command x of the floating body * Is used as an input value to output a command value i of the current value i * A position servo 13 is provided, and the detected position x of the floating body is fed back to the position servo 13, and state feedback control for feeding back the state quantity of the floating body downstream of the position servo 13 is configured to be performed. And at least one of the current value i output from the current control device 7 or the command value i of the current value i input to the current control device 7 * Can be further fed back to the position servo 13 as a current feedback signal 14. In this way, by combining the feedback of the current feedback signal 14 with the position servo type state feedback control, high-response zero control can be realized.

[0053] Also, the control system of the magnetic levitation device of the present embodiment is configured such that the command value i of the current value i input to the current control device 7 * Can be fed back to the position servo 13 as a current feedback signal 14. In this way, by feeding back the command value i instead of the current value i * To the position servo 13, the above control can be performed while eliminating the need for current detection.

[0054] Also, the control system of the magnetic levitation device of the present invention is configured to be able to switch the on / off of the current feedback signal 14. In this way, position control and zero power control can be easily selected and switched.

[0055] Therefore, according to the above-described present embodiment, zero power control can be realized simply and suitably.

[0056] Furthermore, the control system of the magnetic levitation device of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0057] 2 Magnet Unit 5 Permanent Magnet 6 Electromagnet 7 Current Control Device 9 Control Device 13 Position Servo 14 Current Feedback Signal i Current Value i * Command Value x Displacement (Position) x * Position Command

Claims

1. A control system for a magnetic levitation device, comprising a magnet unit including an electromagnet and a permanent magnet, a current control device for inputting an exciting current to the electromagnet, and a control device for inputting a command value of a current value to the current control device, for supporting a floating body by the magnetic force of the magnet unit and controlling the position of the floating body, comprising a position servo that outputs a command value of a current value using a position command of the floating body as an input value, feeding back a detected position of the floating body to the position servo, configured to perform state feedback control for feeding back a state quantity of the floating body downstream of the position servo, and configured such that at least one of a current value output from the current control device or a command value of a current value input to the current control device can be further fed back to the position servo as a current feedback signal. A control system for a magnetic levitation device, characterized by the above.

2. Configured such that a command value of a current value input to the current control device can be fed back to the position servo as the current feedback signal. A control system for a magnetic levitation device according to claim 1, characterized by the above.

3. Configured such that the on / off of the current feedback signal can be switched. A control system for a magnetic levitation device according to claim 1, characterized by the above.

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