JPS60119402A - Tactile sense device - Google Patents

Abstract

PURPOSE:To execute automatically a measurement by rejecting a reaction force caused by a displacement of an elastic body for giving a force to an article, and obtaining information for showing a state of the article basing on a displacement quantity of the elastic body. CONSTITUTION:When a parallel spring 3 is displaced and bent, its displacement quantity is detected by an output of a strain gauge 9. A moving part 5 of a moving mechanism can execute a movement of a large stroke by a rotation of a DC motor 14. The outside of a nut part 11 of the moving part 5 can slide against a guide 16 fixed to a housing, through a linear bearing 12. Its rotational angle is proportional to a moving extent of the moving part 5 of the moving mechanism by a feed screw 10.

Description

Detailed Description of the Invention] (N Technical Field of the Invention The present invention relates to a tactile device, particularly a tactile device that measures three-dimensional dimensions, etc. by bringing a contact probe (contact probe) into contact with an object to be measured. This invention relates to a tactile device that can measure even soft objects.

(Bl) Conventional technology and problems With the progress of FA (factory automation), automatic measurement of three-dimensional dimensions is also progressing.

Automatic measurement of highly rigid parts can be covered with current technology, but automatic measurement of soft parts, such as minute spring parts such as gimbals of magnetic disk heads, thin plastics, sponge products, etc., requires minute force. There are significant delays due to the lack of controllable contacts. In other words, the contacts used in conventional shape measuring machines that measure three-dimensional dimensions are supported by springs in order to perform stable measurements, and the spring constant is relatively low, for example, 801/square or more. Therefore, there was a problem that it was not suitable for measuring the dimensions of small parts with low rigidity.

(Q. Purpose and Structure of the Invention The present invention aims to solve the above problems. For example, large strokes are corrected by rotating a feed screw, and small strokes are corrected by a voice coil motor. It is an object of the present invention to provide a companion tactile device that enables a contactor to touch a fixed object.Therefore, the tactile device of the present invention receives a force application command and applies the commanded force to an object. The method includes a force applying mechanism that applies force through a child, brings the contact child into contact with the article, and indicates the aspect of the article based on the displacement of the contact child due to a relative positional change between the contact child and the product. The force applying mechanism is a tactile device for obtaining information, and the force applying mechanism includes a drive unit that generates a force and the contactor is supported, and the contactor is displaced against the article by receiving force from the drive unit. a force applying means for applying a force via the force applying means; a displacement detecting means for detecting the displacement of the force applying means; and a force applying means receiving an amount corresponding to the displacement of the force applying means and the force applying command, and based on the signals thereof. and drive control means for controlling the drive unit so that the contactor applies a force corresponding to the force application command to the article, and the contactor includes a drive control means for controlling the drive unit so that the contactor applies a force corresponding to the force application command to the article, The present invention is characterized by comprising means 17 for obtaining information indicating the aspect of the article.

Another aspect of the present invention includes a force applying mechanism that receives a force applying command and applies the commanded force to an article via a contact, and a moving mechanism that movably supports the force applying mechanism,
A tactile sensation that brings the contactor into contact with the article and obtains information indicating the aspect of the article based on the amount of displacement of the contactor due to a relative positional change between the contactor and the article and the amount of displacement of the moving mechanism. In the device, the force applying mechanism includes a drive section that generates a force and the contactor supported, and is displaced by the force of the drive section to apply force to the article through the contactor. a force applying means for applying a force; a displacement detecting means for detecting displacement of the force applying means; and a drive control means for controlling the drive unit so that the contactor applies a force corresponding to the force application command to the article, and a displacement of the force application means detected by the displacement detection means. and means for obtaining information indicating the aspect of the article based on the displacement amount and the displacement amount of the moving mechanism.

The temperature according to the embodiment will be explained below with reference to the drawings.

(DI Example of the Invention Fig. 1 is an external view of one embodiment of the present invention, Fig. 2 is a cross-sectional view of the embodiment shown in Fig. 1, Fig. 3 is a cross-sectional view of the voice coil motor portion, and Fig. 4 is a main view of the embodiment shown in Fig. 1. Control block diagram related to the invention, fifth
The figure shows an example of a displacement signal output circuit using a strain gauge.

In the figure, l is a contact and 2 is a voice coil motor.

3 is a parallel spring, 4 is a stopper, 5 is a movable part of the moving mechanism,
6 is a housing, 7 is a robot arm, 9 is a strain gauge, 10 is a feed screw, 11 is a nut part, 12 is a linear bearing, 13 is a bearing, 14 is a DC motor, 15 is an angle encoder, 16 is rotation of the nut Stop and guide, 20 is a yoke, 21 is a magnet, 22 is a voice coil,
23 represents a stopper, and 24 represents an object to be measured.

A contact probe 1 is attached to the movable part of the voice coil motor 2, and is configured to move up and down so as to contact the object to be measured with a predetermined pressure. The movable part of the voice coil motor 2 is elastically supported by two parallel springs 3, and the movable part of the voice coil motor 2 is elastically supported by two plate-shaped spring bodies. The parallel spring 3 is movable.Meanwhile, the stator of the voice coil motor 2 is attached to the movable part 5 of the moving mechanism, and the support base of the parallel spring 3 is also movable.
5 is installed. The housing 6 is attached to a robot arm 7, for example, when shape measurement is performed using a robot.

As shown in FIGS. 2 and 3, a strain gauge 9 is attached to the parallel spring 3, and when the parallel spring 3 is displaced,
When deflection occurs, the amount of displacement can be detected by the output of the strain gauge 9. The movable part 5 of the moving mechanism is engaged at the nut part 11 with a feed screw 10 connected to the rotating shaft of a DC motor 14, and can be moved over a large stroke by rotation of the DC motor 14. The outer side of the nut part [l] of the movable part 5 is slidable on a guide 16 fixed to the housing 6 via a linear bearing 12.

The guide 16 also serves to prevent the nut from rotating.

An angle encoder 15 is attached to the shaft of the DC motor 14, so that the rotation angle of the DC motor 14 can be detected. This rotation angle is proportional to the amount of movement of the moving mechanism movable part 5 by the feed screw lO.

As shown in FIG. 3, for example, the voice coil motor 2 is composed of a magnetic circuit section consisting of a yoke 20 and a permanent magnet 21 attached thereto, and a voice coil 22 which is a movable section. A magnetic force is generated corresponding to the current applied to the The displacement mechanism by the voice coil motor 2 is frictionless, and the movement mechanism by the feed screw lO is frictionless.

A block diagram of the control system of the voice coil motor 2 and the direct ML motor 14 is as shown in FIG.

Note that the viscous damping coefficient is ignored. In FIG. 4, SWx and SW2 represent analog switches for mode switching.

Further, the contents of the parameters used in FIG. 4 and the following explanation are as follows.

U(a): Input S to voice coil motor Nira plus operator Om, Oc: Open loop gain Dm, Dc of logical operation element
: Viscous damping coefficient B : Air gap magnetic flux density of voice coil motor! = Length of winding of voice coil motor Lc: Inductance RC of voice coil motor: Resistance between terminals of voice coil motor 1 [c H t-current feedback constant VC of voice coil motor
= Speed feedback constant of voice coil motor PC = Position feedback constant of voice coil motor 1V1c : Mass of moving part of voice coil motor k : Spring constant of parallel spring Xc : Displacement of parallel spring Km : Induced voltage constant of DC motor Lm : DC Motor inductance RJn: Resistance between terminals of DC motor 1m = Current feedback constant of DC motor ■m: Speed feedback constant of DC motor Pm: Position feedback constant of DC motor Mm: Moving part of voice coil motor from load mass of DC motor Subtracting mass
As can be seen from the pressing force in FIG. 4, in the example of a single VC trip, the voice coil motor and @αC motor are controlled as one hybrid motor. The movement command for the contactor 1 is given only to the control section of the voice coil motor 2, and the current value of the displacement amount of the voice coil motor 2 and the Made to give speed. The key points of this control are: ■ Positive feedback of the signal from the strain gauge 9 used as a displacement sensor to the voice coil motor 2 so as to cancel the spring force of the parallel spring 3; ■ The contact force command value is: Voice coil motor generated force sl
Calculate from 5. ■ The displacement signal and speed signal from the strain gauge 9 should be input to the DC motor 14 as negative signals.

etc. Regarding (■) above, the air gap magnetic flux density B of the voice coil motor 2 is different from that of a rotary motor; it is constant over the operating range, and the generated force has high linearity with respect to the current, so the calculated value and the measured value are Good match.

For example, when the contact l is separated from the measurement target 24,
Assume that a contact force on the Durham order is instructed to the voice coil motor 2. Due to the input Qs) at this time, the movable part of the voice coil motor 2 is displaced toward the measurement object 24 with a constant force. Then, the DC motor 14 rotates so that the displacement of the parallel spring 9 becomes zero. At this time, no matter how much the DC motor 14 rotates, the displacement Xc of the parallel spring S cannot be made zero, as is clear from FIG.

(However, this does not apply when the acceleration generated by the DC motor 14 is extremely large.) Therefore, the movable part 5 of the moving mechanism is pushed out by the feed screw lO, and the contact l is moved toward the object to be measured. Then, before the movement system of the support mechanism comes into contact with the measurement object, Mc'xc+(Mm+Mc)'im=-D
mim+KmIm-Fr ・=(11Mc('iBjuchic)=-kx(-DcMc-1-BIIc ・(2
1LmIm == RmIm+Em Kmxm-(3)
L c I c =-Rc I c-)-Ec-B
... (4) was, from the time when the contact l came into contact with the object to be measured, Mm'xc=-kx(+BIIc-4-KmIm-Fr
-(Dm×Dc)%C...(5) Lm? m=-Rm Im-4-lm-4-E C-(
6) LcIc=-RcIc+Ec-B7 Moxibustion C...(7
). If the contact point is taken as an initial value (time t-0) and the transfer function of the control system at this time is calculated, it can be expressed as follows. Here, the open loop gain of the operational amplifier is Om = Oc w o.

It is assumed that

-1-Fr(a)...(8) The following is clear from this equation (8).

■ This control system is observable and controllable.

Km Kc (however, -Pm--Pc 10k) in the range of 0. )
:[m Ic ■ A steady position error occurs for step input.

■ Steady position error occurs due to the presence of friction.

■ Two actuators can be controlled as one hybrid motor.

By the way, if you try to control the position using only one DC motor without using a voice coil motor, normally,
Since a moving mechanism such as a feed screw has large friction, a dead zone exists in the control system, making it difficult to control force on the Durham order. In other words, it is nearly impossible to control the force below the frictional force of the moving mechanism. The characteristic of the above-mentioned formula (8) represents the same characteristic as in the case of one DC motor, and there is no improvement in one-position control or movement. However, the relationship between the pressing force F(s) generated by the voice coil motor 2 and the input is as follows. Therefore, the position feedback constant Pc is set as c, and the velocity feedback is returned to stabilize the system. If the constant Vc is set to zero, F(s) is related to displacement (and can be controlled without time delay or steady-state error. In other words, accurate pressing force control at the same time as contact is possible to reduce the steady-state position error of the DC motor. In addition, even if Vc is set to zero, the damping of the system will not become zero due to the viscous damping (very small value) of the voice coil motor, and the system will remain stable.

In order to establish the above equation 00, linearity regarding the displacement of the sensor that detects the spring constant k is a problem. (Since the strain gauge 9 has a structure that allows the strain gage to be bent, it is possible to detect k with high accuracy without being affected by twisting or the like.

As described above, the haptic device makes it possible to precisely control the pressing blade regardless of disturbances such as friction. In addition, although there is some error, the contact element always contacts the object to be measured in a posture where the amount of displacement of the parallel spring is almost zero. The life of the moving mechanism etc. is long.

Furthermore, the response time of the main force control system is determined by h, as can be seen from the above equations (8) and (11). Generally, as h becomes larger, the control system becomes unstable and enters an oscillating state.

At this time, the frictional force acts to dampen this oscillation. In this force control system, position errors due to friction are irrelevant to force control, so by increasing the frictional force of the system, the coordination of the system can be improved. Therefore, if a feed screw or the like is used as a moving mechanism, the friction is relatively large, which is useful for improving the coordination of the system.

The dimensions of the object to be measured are determined by the rotation angle of the feed screw IO detected by the angle encoder 15 shown in FIG. 2 and the displacement of the parallel spring 3 detected by the strain gauge 9.

Next, an example of a measurement method using the haptic device according to this embodiment will be described.

■ Setting of contact pressure Since the force on the parallel spring 3 due to the mass of the movable part of the voice coil motor 2 changes depending on its posture, it is necessary to correct its own weight each time the posture changes. This self-weight correction is performed in the following manner.

First, the contactor 1 is set in a predetermined posture.

Next, in the control block diagram shown in FIG. 4, the analog switches SWI and SW2 are switched to set the input signals of the DC motor 14 and the voice coil motor 2) to zero, and the position displacement amount to the voice coil motor 2 is set to zero. Leave a negative feedback. By this operation, the parallel spring 3 is held at the neutral point. This can be realized, for example, by processing the signal from the strain gauge 9 using a Wheatstone bridge as shown in FIG.

In FIG. 5, Vcc represents a power supply voltage, 30 represents an operational amplifier, and 31 represents a detection resistor.

Negative feedback of the amount of positional displacement generates a current flowing through the voice coil motor 2 or a force balanced with its own weight. If this current value is converted into a digital quantity by an analog/digital converter (not shown), stored in a memory under the control of an external processor, and this value is added to the contact pressure indication value, the predetermined contact pressure can be determined. can be output.

■ Setting of initial values First, the control block diagram in FIG. The connection is such that the displacement of is given as input.

Then, negative contact pressure is applied to the voice coil motor 2 to press the stopper 4 against the housing 6 with a constant pressure. At this time, the pulse counter of the angle encoder 15 is reset, and the amount of displacement of the voice coil motor 2 is stored in the memory, and this is set as an initial value.

■Measurement If the above processes ■ and ■ have been completed, measurements can be performed in measurement mode as long as there is no change in posture.

The dimensions of the object to be measured can be easily determined from the phase or difference between the amount of movement of the screw and the amount of displacement of the parallel spring.

19- can be recognized.

(2) Detailed Description of the Invention According to the present invention, as described in detail, it is possible to support a contact so as to maintain a minute contact pressure on the order of grams, for example. In particular, there are the following advantages:

■ Since the position of the contactor can be roughly set, it is easy to initialize the measurement and automate the measurement.

■ Even if the object to be measured does not comply with the comparative terms and conditions, it will not be damaged (it can be measured).

■ It is easy to program and teach automatic measurements.

(2) For example, it can be mounted on a robot arm and feed back the contact signal to enable automatic dimension measurement.

In addition, since the mounting position of the haptic device is usually at the tip of the robot arm, it is only necessary to add the coordinate position of the tip of the robot arm and the output value of the angle encoder. ) position in the robot coordinate system 20-

[Brief explanation of the drawing]

Fig. 331 is an external view of one embodiment of the present invention, Fig. 2 is a sectional view of the embodiment shown in Fig. 1, Fig. 3 is a sectional view of the voice coil motor portion, and Fig. 4 is a control block diagram related to the present invention. , FIG. 5 shows an example of a displacement signal output circuit using a strain gauge. In the figure, l is a contact, 2 is a voice coil motor, 3 is a parallel spring, 4 is a stopper, 5 is a movable part of the moving mechanism, 6 is a housing, 7 is a robot arm, 9 is a strain gauge, and 10 is a feeder. P screw, 11 is a nut part, 12 is a linear bearing, 13 is a bearing, 14 is a DC motor, 15 is an angle encoder, 16 is a nut rotation stopper and guide, 2
0 represents a yoke, 21 a magnet, 22 a voice coil, 23 a stopper, and 24 an object to be measured. T! # Patent application applicant Shitsu Co., Ltd. Hiraito H (Hosho letter (at the time of request for examination) December 28, 1980 1, case indication 1982 patent application No. 226302 2, title of invention haptic device 3, Relationship with the person making the amendment Patent applicant address 1015 Kamiodanaka, Nakahara-ku, Yozaki-shi, Kanagawa Name (522) Fujitsu Co., Ltd. Representative Takuma Yamamoto 4 Agent address 4-17 Nishi-Nippori, Arakawa-ku, Tokyo No. 1 Sawara Mansion 3FC Name (7484) Patent attorney Mori 1) Hiroshi (1 other person)
Detailed Description of the Invention Column-7, Contents of Amendment Contents of Amendment (1) The Scope of Claims column is amended as follows as shown in the attached sheet. Self-equipped with a force-applying mechanism that receives a force-applying command from the user and applies the commanded force to the article via a contactor,
A tactile device that brings the contactor into contact with the article and obtains information indicating the aspect of the article based on a displacement i of the contactor due to a relative position change between the contactor and the article, the haptic device comprising: 3. A tactile device characterized in that the imparting mechanism is provided with means for obtaining information indicating the aspect of the object. ``The power of the cow means driving the book''
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(6) A force applying mechanism that receives a force applying command and applies the commanded force to an article via a contactor, and a movement that movably supports the force applying mechanism. a mechanism, the contactor is brought into contact with the article, and the B of the article is determined based on the amount of displacement of the contactor due to the relative position change between the contactor and the article and the amount of displacement of the moving mechanism.
A haptic device that obtains information indicating a condition, the force applying mechanism comprising: A tactile device characterized in that a movable part that imparts a force to the object is provided with means for arching to obtain information indicating the aspect of the article. ! Equipment □ 00) Liao ■■ Illusionary tax measure 乎月巾盈'' 1 body 1 body μm ■ tζ (
2) In the specification, from page 5, line 15 to page 6, line 12, the statement ``receiving a force application command, and -=---characteristics'' is amended as follows. [Equipped with a force applying mechanism that receives a command to apply force to the article and applies the commanded force to the article via a contact, brings the contact into contact with the article, and controls the relative relationship between the contact and the article. The haptic device obtains information indicating the aspect of the article based on the amount of displacement of the contact due to a change in position. The force applying mechanism is a force generating means in which a movable part that applies a force to one article is directed by an elastic body. The device further includes a reaction force canceling means for driving the force generating means so as to cancel a reaction force of the elastic body generated when the elastic body is displaced. The article is characterized by comprising means for obtaining information indicating the mode of the article based on the amount of displacement of the elastic body. (3) In the specification, from page 6, line 13 to page 7, line 13, the statement ``In response to an instruction to provide one feature, and one feature'' is amended as follows. [Equipped with a force applying mechanism that receives a force applying command to the article and applies the commanded force to the article via a contact, and a moving mechanism that movably supports the force applying mechanism, A tactile device that is brought into contact with an article and obtains information indicating an aspect of the article based on the amount of displacement of the contact and the amount of displacement of the moving mechanism due to a relative positional change between the contact and the article, , the force applying mechanism includes a force generating means in which a movable part that applies a force to the article is defined by an elastic body, and a force generating means configured to cancel a reaction force of the elastic body generated when the elastic body is displaced. The article includes a reaction force canceling means for driving the force generating means, and means for obtaining information indicating the mode of the article based on the amount of displacement of the elastic body and the amount of displacement of the moving mechanism. Characterized by becoming.”
. that's all.

Claims (1)

[Scope of Claims] (11) A force applying mechanism that receives a force application command and applies the commanded force to an article through a contact, the contactor is brought into contact with the article, and the front-distribution contact A tactile device that obtains information indicating an aspect of the article based on a displacement of the contact due to a relative positional change between the contactor and the article, wherein the force applying mechanism includes a drive unit that generates a force, and a drive unit that generates a force, force applying means for applying a force to the article via the contact element by displacing the child when the child is supported; and a displacement detection unit for detecting displacement of the force applying means. the drive unit receives the force application command, an amount corresponding to the displacement of the force application means, and the force application command, and the contactor applies a force corresponding to the force application command to the article based on those signals. A tactile device characterized in that it is configured to include a drive control means for controlling the object, and a means for obtaining information indicating the aspect of the article based on the output of the displacement detection means. 2) The haptic device according to claim (1), wherein the drive section is a voice coil motor. (3) The force applying means is a parallel plate spring full valve. Claim 1 or 2, characterized in that the contactor is configured to support the contactor, and the displacement detection means is configured to detect displacement of the parallel leaf spring. The tactile device according to paragraph (2). (4) A force applying mechanism that receives a force applying command and applies the commanded force to the article via a contact, and a movement that movably supports the force applying mechanism. a mechanism, the contactor is brought into contact with the article, and the mode of the article is determined based on the amount of displacement of the contactor due to a relative positional change between the contactor and the article and the amount of displacement of the moving mechanism. The force-applying mechanism is a tactile device that obtains information indicating the object, and the force-applying mechanism includes a drive section that generates a force, and the contactor is supported, and is displaced in response to a force from the drive section to apply the force to the article. a force applying means for applying a force through a contact; a displacement detecting means for detecting displacement of the force applying means; and a signal for receiving an amount corresponding to the displacement of the force applying means and the force applying command; drive control means for controlling the drive section so that the contactor applies a force corresponding to the force application command to the article based on the force applied by the displacement detection means; A tactile device comprising: means for obtaining information indicating the aspect of the article based on the amount of displacement of the applying means and the amount of displacement of the movement and structure. (5) The haptic device according to claim (4), wherein the drive section is constituted by a voice coil motor. (6) The force applying means is configured to support the contact through a parallel plate spring, and the displacement detection unit is configured to detect displacement of the parallel plate spring. A haptic device according to claim (4) or (5), characterized in that: (7) The drive unit is configured to receive positive feedback of the displacement signal from the displacement detection means, and the 5kJJ mechanism is configured to input negative input signals to the displacement signal and speed signal of the force applying means. Claim No. (4) characterized by
Tactile devices as described in Section 1.