JP2008022694A - Detection device and detection method for dynamic thrust acting on moving body, and electromagnetic force detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a force detection method that enables to accurately detect dynamic thrust acting on a moving body including a moving element of a linear actuator. <P>SOLUTION: A force sensor 5 is mounted between the moving element 3 of a testing linear actuator 1 and the moving element 4 of a load linear actuator 2. Displacement of the moving element 4 is measured by a displacement sensor 6. The dynamic thrust (an electromagnetic force) generated by the testing linear actuator 1 is estimated on the basis of the force detected by the force sensor 5 and a displacement amount detected by the displacement sensor 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus and method for detecting a dynamic thrust acting on a moving body, and an electromagnetic force detection apparatus.

Nowadays, linear motors (actuators) are used for driving pistons such as compressors because they can be reciprocated with little loss by using both a mover and a spring. Furthermore, in driving using resonance, a large driving amplitude can be obtained with a small input power. Moreover, the compressor system using the linear motor as described above achieves high efficiency.
In developing linear motors and systems for these applications, there is an increasing need to accurately evaluate the power consumption and efficiency of linear motors.

In measuring the efficiency of a linear motor, it is necessary to measure the output of the linear motor (the product of the motor generated thrust and the motor speed).
As a linear motor thrust measuring apparatus, there is an apparatus shown in FIG. That is, a test linear motor is prepared on one side and a linear motor for a simulated load is prepared on the other side, and the thrust is measured by a load cell connecting the respective movable parts.
Specifically, the mover 3 of the linear motor 1 and the mover 4 of the linear motor 2 are connected via a force sensor 5, and the force sensor 5 and the displacement sensor 6 act on the movers 3 and 4. Force is detected (see Patent Document 1).
In the conventional detection device, when both the movers 3 and 4 are stationary or moving at a constant speed, the force acting on the movers 3 and 4 can be accurately detected by the force sensor 5. .
JP 2000-270534 A

  However, in the configuration as described above, when the momentum of the movers 3 and 4 is changed (if the masses of the movers 3 and 4 are unchanged, they are accelerating or decelerating), There is a problem that the dynamic thrust acting on the movers 3 and 4 cannot be detected accurately. The dynamic thrust here is an electromagnetic force generated by the linear motor 1. This is because the mover 3, 4 and the entire force sensor 5 move as a unit, and the force sensor 5 detects the force acting on the entire mover 3, 4, and the movement acting only on the mover 3 or 4. This is because the thrust cannot be detected, and a phase shift occurs in the force generated by the two linear motors 1 and 2 due to a time change (frequency change).

There is also a problem that the dynamic thrust, which is the output of the linear motor, cannot be measured accurately.
In particular, in the thrust measurement in the vicinity of the resonance point, the force on the simulated load side is also applied to the load cell, so that a force greater than the thrust of the linear motor to be actually measured is measured. Therefore, the efficiency measurement of the linear motor system cannot be performed accurately, making it difficult to evaluate the energy saving effect.
Even when an actual load (compressor, molding machine, press machine) is driven by a linear motor instead of a simulated load and a force detection device is provided between them, accurate detection cannot be performed for the above reason. That is, in Patent Document 1, the force detected by the force sensor 5 is the sum of dynamic thrust (electromagnetic force) generated by the linear motor 1, inertial force, spring force, and damping force (a spring is attached). The force that the linear motor 1 outputs to the outside), and the dynamic thrust (electromagnetic force) generated by the linear motor 1 cannot be measured.

The present invention has been devised in view of the above-described conventional circumstances, and even when the momentum of a moving body is changing, the dynamic thrust acting on the moving body can be accurately detected. It is an object of the present invention to provide a detection device and a detection method for a dynamic thrust acting on a moving body. That is, the present invention provides a method for measuring the dynamic thrust (electromagnetic force) of a linear motor by subtracting the inertial force, spring force and damping force from the force detected by the force sensor.
The present invention also provides an electromagnetic force detection device capable of accurately detecting the electromagnetic force acting on the mover even when the momentum of the mover of the electromagnetic drive device is changing. With the goal.

In order to solve the above problems, the present invention provides the following means.
A device for detecting a dynamic thrust acting on a moving body according to the present invention is provided between a load moving body that applies a load to a test moving body, and the test moving body and the load moving body. Applied to the test moving body based on the force sensor, the displacement sensor for measuring the position of at least one of the two moving bodies, and the output value of the force sensor and the output value of the displacement sensor. An arithmetic means for calculating a dynamic thrust is provided.
In this case, a spring coupled to the test moving body or the load moving body may be further provided.
According to another aspect of the present invention, there is provided a method for detecting a dynamic thrust acting on a moving body, wherein the dynamic thrust acting on the test moving body is estimated based on a dynamic model of the force detection device according to claim 1. It is said.
Furthermore, the method of detecting a dynamic thrust acting on the moving body according to the present invention includes a load moving body that applies a load to the test moving body, and the test moving body and the load moving body. In the dynamic thrust detection device comprising the force sensor provided in the first position and a displacement sensor for measuring the position of at least one of the two moving bodies, the moving body for testing and the moving body for loading. It is characterized by exercising at the same frequency and detecting the dynamic thrust acting on the test moving body based on the output of the force sensor and the output of the displacement sensor.
An electromagnetic force detection device according to the present invention is a detection device of electromagnetic force acting on a mover of an electromagnetic drive device, and a load mover that applies a load to the mover of a test electromagnetic drive device; A force sensor provided between the test mover and the load mover; a displacement sensor for measuring the position of at least one of the two movers; and an output value of the force sensor; And an arithmetic means for calculating the electromagnetic force acting on the test mover based on the output value of the displacement sensor.

  According to this invention having the above-described characteristic configuration, the dynamic thrust acting on the moving body is calculated based on the detection value of the force sensor and the detection value of the displacement sensor. As described above, even when the momentum of the moving body changes, the dynamic thrust acting on the moving body can be accurately detected.

The best mode for carrying out the present invention will be described below with reference to the drawings.
As an example of the moving body, a mover of a linear actuator (hereinafter abbreviated as LA) as an electromagnetic drive device is used, and details of the present invention will be described based on the mover. The dynamic thrust acting on the mover is an electromagnetic force generated by LA.

  FIG. 1 shows an embodiment of a detection apparatus according to the present invention. In the detection device of this embodiment, a force sensor 5 is mounted between the mover 3 of the test LA1 and the mover 4 of the load LA2. The displacement of the mover 4 of the load LA 2 is measured by the displacement sensor 6. As the displacement sensor 6, for example, a non-contact type laser displacement meter is used. Reference numeral 7 denotes a bearing that supports the movable element 3 so as to be able to reciprocate. In this embodiment, a leaf spring is used.

FIG. 2 shows a dynamic model for detecting the dynamic thrust of the linear actuator 1. The dynamic model of FIG. 2 represents the detection apparatus shown in FIG. 1 as a dynamic model. The mass m _LA involved in the vibration of the test _{LA 1} is the sum of the mass m ₁ of the mover 3 of the test _{LA 1} and the mass m _S of the leaf spring 7 involved in the vibration. The mass of the force sensor 5 is divided into two, m _L1 and m _L2 . The damping constant of the force sensor 5 is ignored. This is because the resonance frequency generated by the spring constant of the force sensor 5 is sufficiently larger than the driving frequency range of the test LA 1 and does not affect the dynamic thrust measurement.
Thereby, the equation of motion of the device for detecting the dynamic thrust of LA1 is expressed by the following equations (Equation 1, Equation 2).

Here, M ₁ : sum of mass of m _LA and m _L1 (= m _LA + m _L1 = m ₁ + m _s + m _L1 ) [kg]
x ₁ : displacement [m] of the mover 3 of the test LA ₁
K _L : Spring constant of force sensor 5 [N / m]
x ₂ : displacement [m] of the mover 4 of the load LA 2
K _LA : Spring constant of test LA1 [N / m]
C ₁ : Damping constant of test LA ₁ [Ns / m]
F _LA : Thrust generated by the test _LA 1 [N]
M ₂ : sum of masses of m ₂ and m _L2 (= m ₂ + m _L2 ) [kg]
m ₂ : Mass [kg] of the mover 4 of the load LA 2
C ₂ : Damping constant of load LA 2 [Ns / m]
F _LDM : Thrust generated by load LA2 [N]

From the above equation, the block diagram of FIG. 3 is obtained. FIG. 3 is a block diagram of a conventional dynamic thrust measuring method (conventional method). Conventionally, the output F _L of the force sensor 5 was a moving thrust. The thrust F _L detected by the force sensor 5 and the estimated value F _e of the dynamic thrust of the test LA 1 are expressed by the following equations (Equations 3 and 4), respectively.

From the above equation, the block diagram of FIG. 4 is obtained as a method of detecting the dynamic thrust of the test LA1. Estimate F _e of the dynamic thrust of the above equation, since an arithmetic value from the displacement x ₂ of the movable element 4 of the output F _L and load LA2 of the force sensor 5, which of the dynamic thrust of the test LA1 The estimated value F _e is used. As shown in FIG. 4, which calculates an estimated value F _e based output F _L to the displacement amount x ₂ is an operation means of the present invention. Furthermore, it may be a filter disposed downstream in order to reduce the noise superimposed on the estimated value F _e.

Figure 5 and 6, was determined by simulation, showing the dynamic thrust (output of the force sensor 5) the frequency characteristic of F _L of the conventional method. At the resonance frequency f = 37.6 Hz, | F _L / F _LA | = 4.2, | F _L / F _LDM | = It is 4.4, the output _{F L,} not only the thrust _{F LA} to test LA1 occurs, load LA2 is also affected by the thrust force _{F LDM} generated. Moreover, since a change in the output F _L and the phase θ by a change in the frequency, the dynamic thrust F _LA of the test LA1 has been shown to not be accurately detected.

FIG. 7 and FIG. 8 show the frequency characteristics of the estimated value F _e of the dynamic thrust in the dynamic thrust detection method of the present invention (hereinafter referred to as the proposed method) obtained by simulation. Ratio of dynamic thrust F _LA and estimated value F _e of test LA 1 at a frequency of 100 Hz or less | F _e / F _LA | = 1 and the delay of the phase θ is 0 °. Furthermore, | F _e / F _LDM | = 0 and has become, the impact of _{F LDM} to _{F e} is not seen. Thus, the ability to accurately detect the dynamic thrust F _LA of the test LA1 by this proposed method is theoretically proven.

Figure 9 shows a comparison between the estimated value F _e of the dynamic thrust caused by the dynamic thrust (output of the force sensor 5) F _L and the proposed method with the conventional method by simulation. The dynamic thrust _{F L} of the conventional method, larger errors than the dynamic thrust _{F LA} is 14%. In the proposed method, F _LA = F _e and the error is 0%, which is completely coincident.

Figure 10, shows a comparison between the estimated value F _e of the dynamic thrust caused by the dynamic thrust F _L and the proposed method with the conventional method by actual measurement. One of the indicators of LA dynamic thrust is the product of thrust constant _Kf and current I. The thrust constant _Kf is obtained by static characteristics. In the case of LA, the dynamic thrust is considered to be smaller than the static thrust due to the influence of eddy current and the like.

As shown in FIG. 10, the dynamic thrust F _L according to the conventional method is 64% different from K _f I, whereas the estimated dynamic force F _e of the proposed method is 7% from K _f I. It has become smaller. Thus, it can be seen that the proposed method can detect the dynamic thrust with higher accuracy than the conventional method.

The leaf spring constituting the bearing 7 has non-linear characteristics. Depending on the magnitude of displacement, M ₁ including the mass m _S of the leaf spring and the spring constant K _LA of the test LA ₁ are the non-linear characteristics of the leaf spring. Affected by. For this purpose, the influence of the parameters M ₁ and K _{LA on} the estimated value F _e of the dynamic thrust was examined.

11, showing the estimated value _{F e} of the dynamic thrust of the test LA1 in which the mass _{M 1} as parameters. When M ₁ changes by ± 5%, the estimated value F _e of the dynamic thrust increases by ± 11%. Thus, a large effect _{of M 1} is given to the _{F e.} Further, the cause of the most error in M ₁ is the mass m _s of the bearing 7 acting on the vibration.

Figure 12, shows the estimated value _{F e} of the dynamic thrust of the spring constant _{K LA} test LA1 that as parameters of the bearing 7. When the spring constant _KLA changes by ± 5%, the estimated value F _e of the dynamic thrust increases by ± 11%. Therefore, the influence of the spring constant K _LA on the estimated value F _e is also great.

Since the mass M ₁ and the spring constant K _LA have a great influence on the estimated value F _e , the more accurate detection of the dynamic thrust is made by using a leaf spring having a smaller mass and linear with respect to the displacement as the bearing 7. It can be performed.

As described above, according to the detection device in the present embodiment, the dynamic thrust acting on the moving body can be accurately detected even when the momentum of the moving body is changing. Further, even if a leaf spring is attached to the load LA2, the dynamic thrust can be detected by the above-described method.
In the present embodiment, the force target is LA, but the present invention is not limited to this, and it is possible to detect a dynamic thrust acting on a moving body such as a rotational motion. At this time, it is possible to detect the dynamic thrust acting by using a spring suitable for the moving body.
Further, according to the proposed method, it is obvious that the dynamic thrust acting on the moving body can be accurately obtained without a spring.

It is a schematic block diagram which shows one Embodiment of the detection apparatus of the force which concerns on this invention. It is a dynamic model of the detection apparatus shown in FIG. It is a block diagram which shows the conventional dynamic thrust measuring device. It is a block diagram of the dynamic thrust measuring device of the present invention. It is a figure which shows the dynamic thrust-frequency characteristic in the conventional dynamic thrust measurement by simulation. It is a figure which shows the phase-frequency characteristic in the conventional dynamic thrust measurement by simulation. It is a figure which shows the dynamic thrust-frequency characteristic in the dynamic thrust measurement of this invention by simulation. It is a figure which shows the phase-frequency characteristic in the dynamic thrust measurement of this invention by simulation. It is a figure which shows the comparison with the dynamic thrust by the conventional detection method by simulation, and the dynamic thrust by the detection method of this invention. It is a figure which shows the comparison with the dynamic thrust by the conventional detection method by actual measurement, and the dynamic thrust by the detection method of this invention. It is a figure which shows the estimated value of the dynamic thrust of the linear actuator for a test which used mass as a parameter. It is a figure which shows the estimated value of the dynamic thrust of the linear actuator for a test which used the spring constant of the leaf | plate spring which comprises a bearing as a parameter. It is a schematic block diagram which shows the detection apparatus of the force which acts on the conventional moving body.

Explanation of symbols

1 Linear actuator for testing (electromagnetic drive device)
2 Load linear actuator 3 Mover (moving body)
4 Mover (Moving body)
5 Force sensor 6 Displacement sensor 7 Bearing (leaf spring)

Claims (5)

A load moving body that applies a load to the test moving body;
A force sensor provided between the test moving body and the load moving body;
A displacement sensor for measuring the position of at least one of the two moving bodies;
Dynamic thrust acting on the moving body, characterized by comprising a calculation means for calculating a dynamic thrust acting on the test moving body based on the output value of the force sensor and the output value of the displacement sensor. Detection device. A device for detecting a dynamic thrust acting on a moving body according to claim 1,
A device for detecting a dynamic thrust acting on a moving body, further comprising a spring coupled to the test moving body or the load moving body.   A method for detecting a dynamic thrust acting on a moving body, wherein the dynamic thrust acting on the test moving body is estimated based on a dynamic model of the dynamic thrust detecting apparatus acting on the moving body according to claim 1. . A load moving body that applies a load to the test moving body, a force sensor provided between the test moving body and the loading moving body, and a position of at least one of the two moving bodies. A method for detecting a dynamic thrust acting on a moving body by a detection device comprising a displacement sensor for measuring,
The test moving body and the load moving body are moved at the same frequency, and the dynamic thrust acting on the test moving body is detected based on the output of the force sensor and the output of the displacement sensor. A method for detecting a dynamic thrust acting on a moving body. A device for detecting electromagnetic force acting on a mover of an electromagnetic drive device,
A load mover for applying a load to the mover of the electromagnetic drive device for testing; and
A force sensor provided between the test mover and the load mover;
A displacement sensor for measuring the position of at least one of the two movers;
An electromagnetic force detection apparatus comprising: an arithmetic means for calculating the electromagnetic force acting on the test mover based on an output value of the force sensor and an output value of the displacement sensor.

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