JPH076860B2 - Tactile sensor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tactile sensor, and more particularly, to a plurality of sensor cells arranged in a matrix on a common flexible elastic floor, and a force applied to each sensor cell. The present invention relates to a tactile sensor that is used by being attached to a robot hand or the like capable of detecting the.

[Prior Art] Conventional robots are often driven by sequence control or open-loop control, and work is performed in a specific limited environment. Therefore, the work content and the ability as a robot are limited. For example, in the case of a big-and-place robot, parts are mounted in a flow work, which is limited to a series of fixed operations such as gripping a specific part, and selecting and gripping different kinds of parts. It has no function.

However, recently, as robots have become more intelligent, sensors having visual and tactile sensations corresponding to human senses have been developed, and robots capable of operating in various environments are being put to practical use. A distributed tactile sensor has been developed as a tactile sensor for such an intelligent robot. Among these sensors, a signal obtained from the sensor when attached to a robot hand or the like and the robot hand grips an object. There is a device in which the gripping force of an object can be controlled and the hardness can be recognized by detecting and performing feedback control.

FIG. 5 shows an example of such a conventional tactile sensor.
In this example, thin conductive rubber strips A and rubber strips B intersecting each other at right angles are combined in two layers, and the rubber strips contact each other against a force applied in a direction perpendicular to the arrangement plane of the rubber strips. This is to detect the change in resistance as the area of the part increases and to know the magnitude of the applied force.

However, with such a conventional tactile sensor, an output proportional to the applied force cannot be obtained, and the output becomes non-linear,
Further, it has a drawback that it is not suitable for detecting the distribution of force with high density.

Therefore, in order to solve the above-mentioned drawbacks, tactile sensors as shown in FIGS. 6 to 8 have been proposed.

6 and 7, 1 is a sensor cell configured as a detection element, 2 is a column on the sensor cell 1, and 11A to 11A.
1D is a semiconductor strain gauge for arranging around the column 2 of the sensor cell 1, for detecting the strain generated in the sensor cell 1, 3 is a bump electrode similarly arranged on the sensor cell 1, and 10 is for holding the sensor cell 1. An elastic floor that acts as an elastic body, and 9 is a flexible wiring board that is disposed on the sensor cell 1 and that is electrically connected to the bump electrodes 3 to guide the signal output from the sensor cell 1 to the outside.

Here, the semiconductor strain gauges 11A to 11D are incorporated in the Wheatstone bridge circuit as shown in FIG.
The force applied to the sensor cell 1 is detected as a strain value by taking out the resistance change in the semiconductor strain gauges 11A to 11D from the terminals at diagonal positions. The power supply to the bridge circuit and the semiconductor strain gauges 11A to 1D are detected.
The output signal from 1D can be taken out through the bump electrode 3 and the flexible wiring board 9.

[Problems to be Solved by the Invention] However, the tactile sensor of the above-described form is
0, the sensor cell 1, the flexible wiring board 9, the pillar 2 of the sensor cell, and the skin provided on the pillar 2, and the like. For example, when an object to be gripped is grasped, the external force transmitted to the sensor cell 1 via the pillar 2 is accurately measured. It can be detected well, but there was a problem in the method of transmitting the external force.

That is, FIG. 9 shows a state in which a gripping object is gripped by the tactile sensor, where 6A is an elastic skin, 13 is a gripping object, and 9 is a flexible wiring board.
When the gripping object 13 is gripped in the middle of the two columns 2, the flexible wiring board 9 is pressed through the skin 6A, and therefore the solder land 3A provided on the lower surface of the flexible wiring board 9 and the sensor cell 1 are The soldering that joins the provided bump electrodes 3 may come off, impairing the sensor function and possibly causing an erroneous operation of the robot.

Further, FIG. 10 is an enlarged view of one of the above-mentioned sensor cells 1, in which the sensor cell 1 and the elastic floor 10 are joined with an adhesive 12.

For this reason, the adhesive 12 must be heated and hardened when assembling the tactile sensor, and the workability is correspondingly poor, and since the amount of information is far less than human sensory functions, accurate gripping force can be detected. I didn't get it.

The object of the present invention is to pay attention to the above-mentioned problems, and in order to solve the problems, external force can be stably transmitted to a sensor cell accurately in a wide range, and more tactile information can be input. Therefore, it is to provide a highly reliable tactile sensor suitable for the development of an intelligent robot capable of autonomously acting.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has a semiconductor strain gauge for strain detection and a bump electrode connected to the semiconductor strain gauge on one surface thereof, A plurality of sensor cells with a pillar supporting the load in the center
Arranged in a matrix on a flexible wiring board on which a circuit for processing signals from the plurality of sensor cells is formed, and a gripping force is transmitted to the plurality of sensor cells via a flexible skin member and the pillar. In the tactile sensor thus configured, the flexible wiring board is provided with loose fitting holes penetrating the plurality of pillars, and solder lands connected to the bump electrodes are provided on both surfaces of the loose fitting hole, and the sensor cell is connected to the flexible wiring. The plurality of sensor cells are arranged so that their center positions are displaced from each other on both sides of the board, and the plurality of columns are alternately loosely fitted into the loose fitting holes from both sides of the flexible wiring board. It is characterized in that they are overlapped with each other while being offset from each other via the wiring board.

[Operation] According to the present invention, the sensor is arranged such that the support pillars of the sensor cell are alternately passed through the loose fitting holes from both sides of the flexible wiring board, and the bump electrodes of each sensor cell are arranged on both sides of the flexible wiring board. Since the connection is made to the provided solder land, the distribution density of the sensor cells can be increased, and the gripping force can be detected with high accuracy with respect to the gripped object.

Embodiments Embodiments of the present invention will be described in detail and specifically below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Sensor cell 1
Has a bump electrode 3 formed by a semiconductor process, a wiring pattern (not shown) and a semiconductor strain gauge as shown in FIG. Also, the sensor cell 1
The column 2 is fixed to the center of the column by metal bonding, and the bottom of the sensor cell 1 and the top of the column 2 integrated with the column 2 are formed in a matrix on the skin members 6A and 6B. The bottomed holes 21A and 21B are alternately fitted from above and below.

3A is a solder land formed on both sides of the flexible wiring board 19, and is a loose fitting hole formed in the flexible wiring board 19.
The solder lands 3A and the bump electrodes 3 are connected to each other above and below the flexible wiring board 19 in a state where the support columns 2 of the sensor cell 1 are penetrated and fixed from above and below via 19A and soldered. Further, 22 is an elastic floor, the specification of which may be selected depending on the size and hardness of the object to be gripped, and thereby the sensitivity of detection by the sensor cell 1 also changes. Therefore, it is possible to freely detect the gripping force of an object from a soft object to a hard object according to its specifications. It is to be noted that FIG. 2 shows the tactile sensor thus constructed in a partially disassembled state.

In the distributed tactile sensor configured as described above, when a target object (not shown) is gripped on the skin member 6A side, the gripping force P acts in the direction of the arrow as shown in FIG. Is transmitted to the back side of the sensor cell 1 and the top of the support column 2 via. That is, according to the present embodiment, tactile information can be obtained with a high density through the sensor cells 1 arranged on both sides of the flexible wiring board 19 with the positions thereof alternately displaced, and an object can be detected with a wider pressure receiving area than in the past. Since it is gripped, the gripping force can be accurately detected with a precision closer to the human sense and recognition function.

3 and 4 show a second embodiment of the present invention.

FIG. 3 shows one sensor cell 1 taken out (illustration of a semiconductor strain gauge is omitted), and FIG. 4 shows an assembled state. That is, the sensor cell 1 of the present embodiment is provided with arcuate notches 1A at the four corners, and the sensor cell 1 has a flexible wiring board 19 as shown in FIG.
A circular space is formed by the four notches 1A facing each other when arranged in a matrix on one surface. Therefore, the loose fitting hole through which the support column 2 can penetrate the flexible wiring board 19 corresponding to this space.
19A is provided, and the support column 2 of the sensor cell 1 shown by the broken line arranged on the back side of the paper is loosely fitted in the loose fitting hole 19A.

Thus, as shown in FIG.
Since the sensor cells 1 are arranged so as to overlap each other in a state where the positions are shifted, the distribution density of the sensor cells 1 can be increased, and the detection pitch by the sensor cells 1 can be maintained evenly. Can receive more accurate information from.

[Effects of the Invention] As described above, according to the present invention, a plurality of sensor cells arranged in a matrix are arranged on both surfaces of a flexible wiring board such that the center positions of the sensor cells are offset from each other. At the same time, since the support columns are alternately loosely fitted into the loose fitting holes provided in the flexible wiring board from both sides, the distribution density of the detection elements can be substantially increased. In addition, since it is possible to accurately detect the grasping force while grasping this accurately and a large amount of tactile information can be obtained, a reliable tactile sense that can contribute to the development of an intelligent robot that can autonomously act. It has become possible to provide sensors.

[Brief description of drawings]

1 is a sectional view showing an example of the structure of a tactile sensor according to the present invention, FIG. 2 is a perspective view showing an array of the tactile sensor of FIG. 1, and FIG. 3 is a sensor cell unit according to a second embodiment of the present invention. FIG. 4 is a plan view showing an array of sensor cells according to a second embodiment of the present invention, FIG. 5 is a perspective view showing an example of a conventional distributed tactile sensor, and FIG. 6 is an application of the present invention. FIG. 7 is a plan view of a sensor cell capable of performing the above, FIG. 7 is a sectional view of a conventional tactile sensor using the sensor cell of the form shown in FIG. 6, and FIG. 8 is a configuration diagram of a bridge circuit formed between strain gauges on the sensor cell, FIG. 9 is a cross-sectional view when a grasped object is grasped by a conventional tactile sensor, and FIG. 10 is a perspective view showing a joined state of a conventional sensor cell with an adhesive. 1 ... Sensor cell, 1A ... Notch, 2 ... Post, 3 ... Bump electrode, 3A ... Solder land, 6A, 6B ... Skin material, 10,22 ... Elastic floor, 19 ... Flexible wiring Substrate, 19A: loose fitting hole, 21A, 21B: bottomed hole.

Claims (2)

[Claims] 1. A plurality of sensor cells, each having a semiconductor strain gauge for strain detection and a bump electrode connected to the semiconductor strain gauge on one surface, and a pillar supporting a load projecting from a central portion of the sensor cell. , Arranged in a matrix on a flexible wiring board on which a circuit for processing signals from the plurality of sensor cells is formed, and a gripping force is transmitted to the plurality of sensor cells via a flexible skin member and the support column. In the tactile sensor thus configured, the flexible wiring board is provided with loose fitting holes for penetrating the plurality of columns, and solder lands connected to the bump electrodes are provided on both surfaces of the flexible fitting board, and the sensor cell is flexible. The wiring boards are arranged on both sides with their center positions offset from each other, and a plurality of the columns are provided from both sides of the flexible wiring board. A tactile sensor characterized in that the plurality of sensor cells are alternately fitted into the loose fitting holes so that the plurality of sensor cells overlap with each other while being shifted from each other via the flexible wiring board. 2. The tactile sensor according to claim 1, wherein the sensor cell is formed in a rectangular shape having arcuate notches at four corners, and is surrounded by notches between adjacent sensor cells. A tactile sensor characterized in that a loose fitting hole is provided in the portion.