JP2000283873A - Device for evaluating impact response of force sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately obtain a true value of the time integration value of acted force by allowing a movable part supported by the guide part of a direct- acting bearing to collide with a force sensor, and by measuring a true force acted on the force sensor according to speed change during the collision. SOLUTION: An entire movable part (movable part) 3 supported by a guide part 2 of a direct-acting bearing is manually moved, and is allowed to collide with a force sensor 4 fixed to a surface plate 6. The time integration value of force acted on the sensor is measured by a measuring instrument (a light wave interferometer, or the like) 8 for measuring the speed of the movable part 3 before and after collision, a measuring instrument (an automatic collimator, or the like) 9 for measuring the attitude of the movable part 3, and a measuring instrument (the automatic collimator, or the like) 10 for measuring the attitude of a guide part 2. Also, a direct-acting static pressure air bearing is used as the direct-acting bearing. Then, a straight line for connecting the center- of-gravity position of the movable part 3 and a collision point 17 is set in parallel with the movable direction of the direct-acting bearing, thus substituting a time integration value of force given to the force sensor 4 as the speed change of the movable part 3 for measuring, and hence achieving accurate measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for evaluating the impact response of a force sensor.

[0002]

2. Description of the Related Art In recent years, in fields such as a destructive test, a demand for evaluation of dynamic response of a force sensor has been increased. Conventionally, as a dynamic response evaluation method of force sensor,
A method to accurately measure the distortion of an elastic body in an environment where a fluctuating force is applied. To set a force sensor between the vibrator and the weight and use the inertia force of the weight as a known fluctuating force. Methods have been proposed.

[0003]

However, in the former, the strain of the elastic body is compared and measured by two completely different methods (a strain gauge and a capacitance displacement sensor) to eliminate the systematic error factor. Within the range of 0.001 to 100Hz
It can be measured with 0.4% uncertainty. However, problems remain, such as the possibility that the state of deformation of the elastic body is changed by hysteresis due to the dynamic force and the static force.

In the latter case, since the force sensor itself also vibrates, there are problems such as correction of the inertia force of the sensor itself, and other effects due to differences in the measurement (calibration) environment.
Further, when one wants to know about a one-shot large wave phenomenon such as an impact response, there remains a problem of how much the response can be predicted from a response in a continuous vibration of a single frequency.

Generally, in order to eliminate the systematic error factor or the Type-B uncertainty factor that is overlooked, various methods should be tried by various organizations and persons as much as possible. At present, in the process of establishing a method for evaluating the impact response of a force sensor, a given impulse,
A method that can determine the true value of the time integrated value of the applied force with extremely high accuracy can be used not only for evaluating the impact response of a force sensor, but also for applying various dynamic calibration methods to the impact response. It is useful for assessing gender and has a great industrial advantage.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention collides a movable portion supported by a guide portion of a linear motion bearing with a force sensor, and acts on the force sensor from a change in speed during the collision. Measuring the true force of
Provided is a device for evaluating the impact response of a force sensor.

[0007] In this device for evaluating the impact response of a force sensor, the movable parts of two opposing collision devices collide with each other, and a condition under which frictional abnormality occurs at the time of collision is examined based on a change in speed at that time. Can be.

In the apparatus for evaluating the impact response of the force sensor, a direct acting static pressure air bearing may be used as the direct acting bearing.

In the apparatus for evaluating the impact response of the force sensor, a straight line connecting the position of the center of gravity of the movable part and the collision point may be set in parallel with the movable direction of the linear bearing.

In the apparatus for evaluating the impact response of the force sensor, a plane mirror may be attached to the movable part, and a change in the inclination may be monitored by a posture measuring device.

An apparatus for evaluating the impact response of this force sensor is as follows.
A desired initial speed may be given to the movable part by the linear actuator.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an apparatus for evaluating the impact response of a force sensor according to the present invention. 1 and 2 are diagrams for explaining the first embodiment. As shown in a sectional view taken along a plane perpendicular to the movable direction in FIG. 1, a linear bearing (1) of a type that supplies air from a guide portion (2) was used. The movable part (3) has an air film (2
The static pressure air bearing (1) supported in 1) was used. A linear actuator (19) is introduced to give a desired initial velocity of 1 cm / s to 10 cm / s to the movable part (3). The mass of the movable part (3) is 11 kg, and the collision point (1
In 7), the tilt of the tilt stage (7) was adjusted so that the movable section (3) was stationary.

A method for estimating an impulse acting on a movable part (3) and an impulse acting on a sensing part (5) of a force sensor (4) from a change in speed of the movable part before and after a collision. Needs to consider the time integration amount of the external force acting between the two speed measurement times. Further, when an instantaneous value of the acting force is estimated from the acceleration of the movable part (3) and the output of the force sensor is to be compared with the estimated value, the inertia force of the damper (18) and the movable part (3) ) Or the instantaneous value of the external force acting on the force sensor. Examples of the external force include an air resistance received from indoor air due to the movement of the movable portion (3), a frictional resistance acting between the guide portion (2) and the movable portion (3), and the like, particularly when the latter is dominant. There are many. In addition, sensor (4)
The influence of the inertial mass due to the mass distribution and acceleration distribution of the sensing part (5) is a problem on the force measurement system side including the force sensor (4).

As shown in FIG. 2, a movable portion (3) having a mass of M kg supported by a guide portion (2) of a linear motion bearing (1) is moved by hand to give an appropriate initial speed, and the platen is mounted on a surface plate. collide with a fixed force sensor, before and after the collision velocity _{(v 1, v 2 [m} / s])
Is measured with a light wave interferometer. On the other hand, the time series of the output F _out of the force sensor at the time of the collision is recorded. It is preferable that the linear motion bearing has a small frictional resistance, or has a reproducible size and can be corrected. Under conditions where external forces such as friction are negligible, the momentum change M (v ₁ -v
₂ ) is equal to the impulse given to the force sensor by the movable part.

Here, the time integral ∫F _out dt of the output of the force sensor calibrated by a static method or a dynamic method such as a method using a vibrator as described above, True impulse 置換 F _real measured displacement as momentum change
The difference from dt is known as the error of the force sensor in the collision.

The shape of the time series of the impact force is the mass of the movable part,
In addition to the initial velocity to be given, adjustment is made by the shape, material, size, etc. of the damper (18) attached to the sensing part (5) of the force sensor (4) or the collision part (17) of the movable part (3). it can.

Further, by measuring the acceleration α of the movable part (3), the instantaneous value of the force can be estimated as Mα. By considering the density distribution and the acceleration distribution of the damper, the instantaneous value of the force acting on the sensing part (5) of the force sensor (4) can be estimated with higher accuracy.

In a dynamic response calibration method using a vibrator that gives continuous vibration at a single frequency, an amplitude change ratio and a phase change amount for each frequency and each amplitude are given as calibration results.
The time series of the force sensor output F _out obtained therefrom is subjected to a Fourier transform, the true values of the respective frequency components are estimated, and these are recombined to obtain the time series of the true values of the forces acting on the force sensors. Can be estimated. This and
By comparing the difference of the force with the time series required with high accuracy by the present method, information on problems inherent in the calibration method of the force sensor can be obtained.

It is necessary to pay attention to the possibility that the posture of the movable part (3) changes due to the moment due to the force acting at the collision point at the time of the collision. The reason is that the moving part (3)
When the shape of the air film between the guide and the guide portion (2) changes, the state of the airflow changes, and the friction characteristics obtained by the above-described method may not be applicable. There is a possibility that the part (3) may come into mechanical contact with the guide part (2).

Therefore, the second embodiment shown in FIG.
By setting the straight line connecting the collision point (17) and the center of gravity of the movable part (3) to be parallel to the direction of movement of the movable part, the force generated in the collision causes the posture change of the movable part (3). To reduce the effect on However, especially when it is desired to reduce the impact by the damper (18), that is, when it is desired to make the impact steep and increase the peak value, components other than the motion direction of the force generated at the collision point (17) during the collision cannot be ignored. May be large. In that case, it is effective to adopt a structure in which the center of gravity of the collision point (17) and the center of gravity of the movable part (3) are completely matched.
For example, the guide portion is separated from the center of gravity of the movable portion by dividing it into two, and the movable portion is hollowed out to form a collision point (17) at the position of the center of gravity.

In the first and second embodiments, the movable part (3)
The change in the tilt of the plane mirror attached to is measured by the autocollimators (9) and (10). In this embodiment, a mirror is mounted on a plane perpendicular to the movable direction, and the inclination of the two degrees of freedom is measured.
It may be possible to measure all three degrees of freedom of the movable part (39 as a rigid body).

The attitude measuring devices (9) and (10) are based on an automatic principle based on the principle of converging parallel light reflected from an object to be measured by a convex lens and calculating the inclination from the displacement of the light spot on the focal plane. A collimator or the like is appropriate. For measuring the in-plane displacement of the light spot, a four-division sensor or the like may be used. In the case of this embodiment, when the posture fluctuates by 10 microradians or more, it is determined to be abnormal, and the collision point (17) is reset and the shape and position of the damper (18) are reset.
However, when using a quadrant sensor, it is necessary to pay close attention to the quality of the return light and to confirm that the return light from sources other than the target is negligible.

The operation of the present invention will be described below with reference to the first embodiment. An impulse response evaluation method for a force sensor, which makes it possible to accurately know the impulse given to the force sensor (4), that is, the time integral of the instantaneous value of the force. A movable part (mass: M) supported by a linear guide as shown in FIG.
kg) by hand and collide with a force sensor fixed to the surface plate, and the impulse ∫F dt [kg m / s] acting on it and the velocity before and after the collision (v ₁ , v ₂ [m / s] ) Is measured with a light wave interferometer.
As a linear bearing with small frictional resistance, a static pressure air linear bearing "Air Slide" (registered trade name of NTN Corporation) is used. Under the condition where the frictional force is negligible, the momentum change M (v ₁ -v ₂ ) of the movable part is equal to the impulse ∫F dt given to the force sensor (4) by the movable part, and ∫F dt = M (v ₁ -v ₂ ) [kg m /
s].

Looking at the time series of the impact force acting on the force sensor (4) and the change in the speed of the movable part in a collision experiment with M = 10.955 kg, the kinetic energy of the movable part due to the collision is about 70% converted to heat energy,
The impulse measured by the force sensor and the momentum of the movable part (3) measured by the light wave interferometer coincided with a difference of about 0.5%.

Here, for the purpose of explaining the principle of the present method, the damper (18) has a thickness of about 5 mm and a sectional area of about 1 cm ^2.
The sponge was used to considerably reduce the impact response, and the conditions were such that the difference between the static and dynamic characteristics of the force sensor (4) was minimized. Here, the force sensor has a structure in which a semiconductor strain gauge is attached to an elastic body (capacity 9.8
N, manufactured by Showa Sokki Co., Ltd.).

The static friction characteristics and dynamic friction characteristics of the used air slide should be evaluated carefully. In the case of Example 1, the dynamic friction force acting on the movable portion (39) was proportional to the speed of the movable portion, and the dynamic frictional resistance was about 10 ^-3 N when the speed of the movable portion was 2 cm / s. If the speed measurement points before and after the collision are the same, the time integrated value of the dynamic friction force cancels out in the going and returning directions and becomes zero.The guide part (2) and the movable part (3) of the air slide (1) the static force acting between was about 10- ^{4 N} / mm. the static force, airflow between the ventilation grooves (23) such as a guide portion and a movable portion air film (21) It is thought to be caused by the pressure difference between the two sides of the ventilation groove dug inside the guide part.

The tilt stage (7) is set to have an apparent horizontal tilt at which the movable section (3) stops at a position where the movable section (3) just contacts the sponge (18). The angle at this time is measured by an autocollimator (10) using a horizontal surface using a liquid surface of silicon oil, mercury or the like as a reference. The time integral over the contact time of this force acting on the moving part is about 0.00016k
gm / s, which corresponds to about 0.03% of the total momentum change. If the sponge is made thinner to make the impact response steeper, the portion due to this static force is reduced. Relative standard uncertainty in impulse measurement given to the force sensor (4) is estimated to be better than 10 ^3.

According to the present invention, the impulse applied to the force sensor (4) is replaced and measured as a change in the speed of the movable part (3), although it is inferior from the viewpoint of arbitrary setting of the frequency and amplitude of the dynamic force. It has the decisive advantage of being able to measure with extremely high accuracy. Further, the force sensor to be measured has a great advantage that it is fixed to the surface plate (6). This method is effective for calibrating the impact response characteristics of the force sensor, and for evaluating errors when a general dynamic characteristic evaluation method is applied to the impact response.

In the experiment, the total amount of impulse acting on the force sensor (4) was replaced and measured as the change in the momentum of the movable part (3) before and after the collision. However, by measuring the acceleration of the movable part during the collision period, the force sensor (4)
It is also possible to replace and measure the instantaneous value of the force acting on. When it is desired to estimate the instantaneous value of the force with higher accuracy, it is conceivable to consider the inertial mass distribution inside the damper and its acceleration distribution and correct its influence.

In an actual calibration device design, by setting a straight line connecting the collision point (17) and the center of gravity of the movable part (3) to be parallel to the movable direction, the posture change of the movable part at the time of collision is achieved. Can be kept small. Sufficient attention must be paid to changes in the attitude of the movable part during a collision, mechanical contact between the movable part and the guide part, and the resulting action of the force between the guide part and the movable part.

The posture angle of the movable portion (3) can be changed by a method other than the autocollimator, depending on the state of movement. The mirror needs to be almost perpendicular to the measurement light of the autocollimator, and when used, the autocollimator or the mirror needs to be aligned quite accurately (optical axis alignment). If the direction of the autocollimator easily drifts (is easily shifted), it becomes difficult to handle. In that case, the moving distances of a plurality of corner cube prisms arranged in a plane perpendicular to the direction of movement are measured simultaneously by an optical interferometer,
A method of deriving the angle change from the difference would be advantageous.

An angle change is obtained by dividing the difference in the moving distance by the distance between the corner cube prisms. There is also an advantage that an interferometer used for velocity measurement can be used together. In particular, when it is desired to measure a posture change in a steep shock response, a method of obtaining a posture from the relative positions of a plurality of corner cube prisms is effective because the light wave interferometer easily supports high-speed sampling.

In order to reduce a measurement error called a sine error (also called Abbe error) with respect to a change in the posture of the movable portion, the corner cube prism constituting the interferometer used for measuring the speed of the movable portion has a force to be calibrated in the direction of motion. Desirably it is coaxial with the sensor. By doing so, only the cosine error occurs, and it becomes extremely resistant to a change in posture.

The interferometer used for velocity measurement measures the Doppler shift at high speeds, and measures the Doppler shift at low speeds.
A method of directly reading the light and dark phases of the light of the interference output is advantageous. If both are used in combination and a signal with higher precision is selected and used depending on the state of the signal, the application range is expanded in a general case.

Next, a second embodiment will be described with reference to FIG. To search for the allowable range of the posture change amount, as shown in FIG. 2, the movable portions (3) and (3 ′) of the two linear motion bearings (1) and (1 ′) are caused to collide with each other. The method of detecting the abnormality of the frictional state from the time series of the acceleration and the amount of change in the momentum is used.

The positions of the collision points (17) and (17 '), the shape, the material, the number of the dampers (18), the mass of the movable part, the initial velocity, and the like are changed to cause a collision. measure. If the sum of the changes in the momentum of the two movable parts, corrected for the influence of friction in the usual manner, is not sufficiently small, it is considered that mechanical contact has occurred due to a change in posture.

As the damper (18), various materials and structures such as sponge, rubber, paper, plastic, and spring can be applied. When it is desired to finely shape a steep impact force, it is also effective to attach a piezo element to a thin and hard damper in series and control the voltage during a collision period.

In this embodiment, the shape of the impact force is adjusted mainly by the damper (18). However, when a force sensor is used, such as in an actual destructive test, besides a single large-impact impact, a different form of impact force may be applied gradually in a very short time. In order to cope with such a case, it is also effective to provide the movable portion with a complicated internal structure such as an elastic body or a mechanical structure instead of an integral rigid body.

In this way, the internal structure of the movable part (3) is appropriately deformed and destroyed by the collision, and the time series of the force acting on the force sensor (4) by the collision is complicated. Can be. In such a case, the steady state before and after the collision, or the center of vibration in the case of an elastic body is known, and if the total amount of change in the momentum of the entire movable part before and after the collision is known, it is the force sensor Equal to the total amount of impulse acting on Furthermore, if the instantaneous value of the acceleration and the inertial force of each part of the movable part can be estimated, the instantaneous value of the force acting on the force sensor can be known.

In a crash test of a large structure such as an automobile, the entire structure is placed on a linear motion bearing, and the total momentum change is precisely measured and compared with the impulse measured by a force sensor. In addition, the error of the force sensor output can be known in the total amount. In this embodiment, one or both of the collision points (17) and (1)
By attaching a force sensor to 7 ') and recording the response waveform at the time of collision together with data such as speed and attitude, it is possible to examine the response when the force sensor (4) is not fixed. In this case, when taking out the lead wire (signal line, power supply line) of the force sensor from the movable part, it is necessary to take measures such as loosening enough for the movable distance so that no force is applied. Alternatively, an amplifier and a set of transmitter devices may be placed on the movable part and connected to the recording device by electromagnetic waves (radio waves, infrared rays, etc.).

Embodiment 3 will be described with reference to FIG.
In this device, a collision point (17) is provided at the position of the center of gravity of the movable part (3) guided linearly by two cylindrical guide parts (2). As a result, the influence of the component of the force generated at the time of the collision perpendicular to the movable direction, which contributes to the change in the posture of the movable part, is reduced. The reason for making the collision point coincide with the position of the center of gravity of the movable part is to reduce the fluctuation of the posture of the movable part at the time of collision.

In the manufacture and use of this device, it is necessary to pay sufficient attention to the friction of the linear motion bearing (1) used. The method for evaluating the frictional characteristics of the hydrostatic air bearing (1) is described in the references (Y. Fujii, H. Fu
jimoto: Measurements of frictional characteristics
of a pneumatic linear bearing, Meas. Sci. Techno
l, Vol. 10, No. 5, pp. 362-366, 1999).

Hereinafter, for reference, a method for evaluating the frictional characteristics of the linear motion bearing used in Examples 1 and 2 will be described. Linear air bearings such as an air slide (NTN Corporation) have features such as high-precision motion characteristics and small friction. Since the air slide is supported by the symmetrical air flow (21) of the couette flow, the static friction is ideally zero and the dynamic friction is the viscous frictional resistance of air. However, in an actual air slide, there is a range in which the movable portion (3) keeps the stationary state at the inclination angle of the guide portion (2), and the center value thereof greatly changes. Unfortunately, no literature is available on this frictional property.

On the other hand, the present inventors have been studying a mass measurement method in a zero-gravity environment, and have used an air slide (1) in a preliminary experiment on the ground to realize a linear motion with small friction. ing. Also, in the impact response evaluation method of the force sensor proposed by the present inventors,
The friction characteristics of the linear motion hydrostatic bearing (1) are extremely important factors. Furthermore, in the superconducting magnetic levitation method aiming at the quantum standardization of mass, a change in the attitude of the superconducting levitation is a major problem, and introduction of a superconducting linear motion bearing is being studied for the stabilization.

Therefore, as a method for measuring static and dynamic friction characteristics of a linear motion bearing (1) having a small friction represented by an air slide, gravity as a temporally and spatially steady acceleration field is used. A method using acceleration g was developed. In addition,
The linear motion bearing to be introduced in the superconducting magnetic levitation method must operate in a high vacuum, low temperature (4.2K) environment.
We are also considering conducting this frictional property evaluation method in a cryostat.

Guide part air supply type linear motion static pressure bearing "Air Slide" (manufactured by NTN Corporation: movable distance 90 mm, maximum mass of movable part 2)
7kg, No load design air film pressure 8mm, air film rigidity 70Nmm
^-1 . The straightness of the guide part was 0.3 mm / 100 mm). The air slide is placed on the variable tilt stage, and the position on the stage is visually read from the scale. Five measurement points are provided on the scale at 10 mm intervals from X = 15 mm to 75 mm,
A point at X = 15 mm is set as a reference point (Position-A). Movable part (3)
Is measured with a light wave interferometer. The mass can be changed by attaching and detaching a weight (total mass of movable part: M = 2kg, 6k
g).

The guide part (2) in which the movable part keeps the stationary state
Range of tilt angle (q_min, Q _max) For movable parts
It was measured at each position x. Measured 6 sets in total
In each set, Position-A is set as the origin (zero point).
Was. Its central value q_C= (q _max+ q_min) / 2 is M = 2kg
At 150 mmrad at X = 75 mm point. straight
Since the degree is 0.3 mm / 100 mm, q_CGuide in
It is thought that the fluid force acting on the part (2) and gravity are balanced
You. The fluid force Mgq_CThe state of change at each position of the movable part
Then, based on Position-A, at X = 75mm point, -3mN
A degree of force is acting.

Also, since the dependence of the movable part (3) on the mass is small, this phenomenon is not "angle" but "force".
Is considered to be essential. The cause of the generation of the fluid force is considered to be a pressure difference between the left and right wall surfaces of the passage groove (23) in which only asymmetrical air flow occurs in design. In this case, the force always acts to move the movable part toward the center position X = 45 mm, and coincides with the direction of the force described above.

The movable portion (3) is angular range remains stationary half width _{q H} = - For _{(q max q m in) /} 2, represents the maximum static friction force of the apparent Mgsinq _H.
Because the dependence of the movable part (4) on the mass is small,
"Power" is considered to be essential. As a cause of the generation of the static friction force, minute unevenness of potential generated between the guide portion and the movable portion (3) can be considered. That is, it is conceivable that a certain amount of force is required to get over each of these minute potential valleys. The unevenness of the potential is considered to be due to the minute unevenness in the surface where the movable portion (3) and the guide portion (4) are in contact with each other across the air film, and the state of the adhered substance such as oil.

The dynamic friction characteristics are obtained by solving the equations of motion of the movable part (3) on the ascending and descending free fall of the movable part (3) in the inclination setting angle range q _Stage = 1-3 mrad of the guide part (2). It can be obtained by: (Use that the direction of the dynamic friction force is opposite and the direction of gravity is the same between the up and down directions.) When the geometric inclination angle q of the guide (2) is small, the acceleration a of the movable portion (3) Let M a = −M gq + F _D , where is the dynamic friction force F _D.

The dynamic friction force _{F D} is, when equal to the viscous frictional resistance _{F Df} of Couette flow, F and m _air as the viscosity coefficient of air _{D = F Df = - m air} S v / h,
Dynamic friction force F _D is the moving part (3) and guide part (2) is proportional to the inner surface area S, the movable portion velocity v in contact with each other across an air layer (21) comprising a vent groove (23), film thickness h Is inversely proportional to

Time averaging for climbing and descending (subscript: m)
When the _{applied, M a up, m = -} M gq up, m - | F D, up, m | M a down = - M gq down, m + | F
_{D, down, m} |, (2)? Considering the formula _{, FD, up, m} / _{FD, down, m} = v _{up, m} / v
_{down, m} .

The time average of the inclination angles during climbing and descending is
Almost equal, q_mI can put it. Therefore, the above three
The formula is F_{D, up, m}, F_{D, down, m}, Q_m,of
Three can be solved as unknowns. The results were obtained by experiment
The kinetic friction force agreed with the theoretical value. Also asked at the same time
Angle of inclination q_mIs the apparent tilt angle (-q_C ) Time average
Value (-q_C )_mAnd set inclination angle q of guide part (2)
_Stage, ((-Q_C ) _m + q_Stage), Matches
did. From this, the fluid force acting when the movable part is stationary
Mgq_CIs the same when the movable part (3) is moving
It turns out to work.

In this method, the gravitational acceleration g as a temporally and spatially steady acceleration field is used for measuring the static and dynamic friction characteristics of the direct-acting static pressure air bearing (1).
As the force acting on the movable portion (3), it is necessary to consider not only the static friction force and the dynamic friction force but also the force generated by the asymmetry of the air flow.

From the above measurements, the force of the guide portion (2) and the movable portion (3) acting on each other via the air film (21) is estimated, and if it is not negligible, it is necessary to correct the force. is there. In general, if the collision time is short and the time interval between the speed measurements before and after the collision is small, it is often unnecessary to correct the friction. For example, when the target accuracy of the impact response characteristic evaluation of the force sensor (4) is about 0.1%, it is often unnecessary to correct the friction.

[0056]

According to the present invention, it is possible to provide an apparatus which can know the true value of the impulse given to the force sensor (4), that is, the time integral value of the applied force, with extremely high accuracy. This device can be used not only to evaluate the impact response of the force sensor (4), but also to evaluate the validity of applying various dynamic calibration methods to the impact response. Is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention;

FIG. 2 is a diagram for explaining a first embodiment of the present invention;

FIG. 3 is a diagram for explaining a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Linear bearing 2 Guide part of linear bearing 3 The whole movable part of a linear bearing 4 Force sensor 5 Sensing part of a force sensor 6 Surface plate (pedestal) 7 Variable tilt stage 8 Measurement for measuring the speed of a movable part 9 (Measuring instrument for measuring the attitude of the movable part (such as an autocollimator)) 10 Measuring instrument for measuring the attitude of the guide section (such as an autocollimator) 11 Corner cube prism (movable part) A measurement point for measuring the velocity of the object is given.) 12 A plane mirror attached to the movable part to measure the inclination angle 13 A plane mirror attached to the guide part to measure the inclination angle 14 Laser beam of the light wave interferometer 15 Parallel light beam of autocollimator 16 Parallel light beam of autocollimator 17 Collision point provided on movable part 18 Damper (on movable part or on collision point Attached) 19 linear actuator 20 vent pipe through the interior of the guide portion 21 air film 22 air outlet 23 air groove 24 air inlet openings

Continuing from the front page (72) Inventor Yusaku Fujii 1-1-4 Umezono, Tsukuba, Ibaraki Pref., National Institute of Metrology (72) Inventor Hiroyuki Fujimoto 1-1-4, Umezono, Tsukuba, Ibaraki Pref. In the laboratory

Claims (6)

[Claims] 1. A movable portion supported by a guide portion of a linear motion bearing is caused to collide with a force sensor.
An apparatus for evaluating the impact response of a force sensor, wherein a true force acting on the force sensor is measured. 2. The apparatus according to claim 1, wherein the movable portions of the two opposing collision devices collide with each other, and a condition under which a friction abnormality occurs at the time of collision is examined based on a change in speed of the two at that time. Evaluation device for impact response of force sensor. 3. The impact response evaluation apparatus for a force sensor according to claim 1, wherein a linear motion static pressure air bearing is used as the linear motion bearing. 4. The apparatus according to claim 1, wherein a straight line connecting the position of the center of gravity of the movable portion and the collision point is set in parallel with the movable direction of the linear bearing. . 5. The evaluation device for impact response of a force sensor according to claim 1, wherein a plane mirror is attached to the movable portion, and a change in the inclination is monitored by a posture measuring device. 6. The evaluation apparatus for impact response of a force sensor according to claim 1, wherein a desired initial velocity is given to the movable section by a linear actuator.