JPH073374B2 - Pressure sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure 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 pressure sensor used by being attached to a robot hand or the like that can detect

[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 pick-and-place robot, parts are mounted in a flow work, and it is limited to a series of fixed operations such as gripping a specific part, and different types of parts are selected and gripped. It has no function.

However, recently, as robots have become more intelligent, sensors having visual and pressure sensations equivalent to human senses have been developed, and robots that can operate in various environments are being put to practical use. A distributed pressure sensor has been developed as a pressure sensor for such an intelligent robot. Among these sensors, a signal obtained from the sensor when the robot hand is attached to a robot hand or the like and 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. 3 shows an example of such a conventional pressure sensor.
In this example, thin conductive rubber strips A and B that intersect each other at right angles are combined in two layers, and the force applied in the direction perpendicular to the arrangement plane of the rubber strips causes the contact portions of the rubber strips to contact each other. It detects the change in resistance as the area increases and the magnitude of the applied force is known.

[Problems to be Solved by the Invention] However, in such a conventional pressure sensor, an output proportional to the applied force cannot be obtained, the output becomes non-linear, and in order to detect the force distribution with high density. It had the drawback of not being suitable.

Therefore, pressure sensors as shown in FIGS. 4 to 6 have been proposed in order to solve the above-mentioned drawbacks.

In FIGS. 4 and 5, 1 is a sensor cell configured as a detection element, 2 is a pressure receiving portion on the sensor cell 1, 11A
Denoted by 11D are semiconductor strain gauges arranged around the pressure receiving portion 2 of the sensor cell 1, for detecting strain generated in the sensor cell 1, 3 is a bump electrode similarly arranged on the sensor cell 1, and 10 is the sensor cell 1 An elastic floor 9 acting as an elastic body is a flexible printed wiring board (hereinafter, simply referred to as a wiring board) 9 which is arranged on the sensor cell 1 and electrically connected to the bump electrodes 3.

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 wiring board 9.

By the way, the pressure sensor of the above-mentioned form is composed of the elastic floor 10, the sensor cell 1, the wiring board 9, and the skin provided on the pressure receiving portion 2 of the sensor cell. The external force transmitted to the sensor cell 1 via the sensor cell 1 can be detected with high density and high accuracy, but there is a problem in the transmission method.

That is, FIG. 7 shows a state in which a gripping object is gripped by a pressure sensor, where 6A is an elastic skin, 13 is a gripping object, and 9 is a wiring board. Two
When gripped in the middle of the individual pressure receiving portions 2, the wiring board 9 is pressed through the skin 6A, and therefore the electrode 3A provided on the lower surface of the wiring board 9 and the bump electrode 3 provided on the sensor cell 1 In some cases, the soldering that joins the parts may come off, which impairs the sensor function and may cause the robot to malfunction.

Further, FIG. 8 is an enlarged view of one of the sensor cells 1 described above, and the sensor cell 1 and the elastic floor 10 are joined by an adhesive 12.

For this reason, the adhesive 12 has to be heated and hardened when the pressure sensor is assembled, and the workability is poor accordingly.

The object of the present invention is to focus on the above-mentioned problems, and in order to solve the problems, it is possible to stably and accurately transmit an external force to a sensor cell in a wide range, and thus, it is possible to detect the gripping force. To provide a high pressure sensor.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention has a semiconductor strain gauge on one surface, and a force applied from the other surface side is output to the output from the semiconductor strain gauge. A plurality of sensor cells that can be detected based on the pressure sensor, a pressure receiving portion that projects from the center of one surface of the sensor cell, and supports the sensor cells against force, and the pressure receiving portions that are arranged in a matrix are individually fitted. An elastic floor having a bottomed hole for supporting the sensor cell and having a signal processing circuit connected to a plurality of sensor cells on the opposite surface that maintains a predetermined distance from one surface of the sensor cell, and the other of the sensor cells. And a flexible skin member that covers the surface of the skin member in common, forming a thin lattice-shaped portion corresponding to the gap between the adjacent sensor cells of the elastic floor and the skin member, and from the outside through the skin member. It is characterized in that the force applied to the plurality of sensor cells is detected.

[Operation] According to the present invention, the force applied by the gripping object or the like from the upper surface side of the skin member can be reasonably transmitted to the plurality of sensor cells supported on the elastic floor by the pressure receiving support portion, and the strain gauge on the sensor cell can be provided. Through this, an accurate output signal corresponding to the above force can be obtained, and by further forming the signal processing circuit integrally on the elastic floor, the workability at the time of assembling the pressure sensor can be improved.

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. The bump electrodes 3 formed in the sensor cell 1 by a well-known semiconductor process, the wiring pattern (not shown), and the semiconductor strain gauges 11A to 11D are the same as those shown in FIG. Reference numeral 2A is a pressure receiving support portion provided as a pressure receiving column which is provided in the center of the sensor cell 1 configured as described above and serves to support the force applied to the sensor cell 1.
Flexible elastic floor 5 attached by soldering to
As shown in FIG. 2, the pressure receiving support portions 2A of the sensor cells 1 are fitted into the bottomed holes 5A formed in a matrix on the upper surface of the sensor cells 1 to hold them on the elastic floor 5 with a predetermined gap. is doing. Further, a conductor pattern 4A is formed on the elastic floor 5, and the pump electrode 3 of each sensor cell 1 is soldered to the solder land 4 of the conductor pattern 4A, so that the output signal from the sensor cell 1 can output the conductor pattern 4A. Signal processing is performed via. Furthermore, on the lower surface of the elastic floor 5, thin-walled portions 5B are formed by the grid-shaped grooves 7 at positions corresponding to the gaps between the sensor cells 1, and the thin-walled portions 5B also attach the pressure sensor to the spherical portion. The bending force of the elastic floor 5 prevents the sensor cells 1 from being adversely affected, and the gripping force is effectively transmitted to each sensor cell 1. Reference numeral 6 denotes a skin member, which is the elastic floor 5 described above.
A lattice-shaped thin portion 6B is formed at a position corresponding to the lattice-shaped groove 7 provided on the lower surface, and then such a skin member 6 is covered on the sensor cell 1.

In the pressure sensor configured as described above, the gripping force P passes through the skin member 6 and the sensor cell 1 through the skin member 6 as shown by the arrow direction.
By being applied from the back side of the object, the object can be gripped with a wider pressure receiving area than before, and the detection range as the pressure sensor can be expanded. Furthermore, according to the present embodiment, by assembling the elastic floor 10 and the flexible wiring board 9 in the pressure sensor of the form shown in FIG. 5, the assembly process of the pressure sensor is simplified. . FIG. 2 is an exploded view of the entire pressure sensor array configured as described above.

[Effects of the Invention] As described above, according to the present invention, the bottomed holes into which the pressure receiving supporting portions of the individual sensor cells are fitted are provided in a matrix on the flexible elastic floor. The semiconductor strain gauge forming surface of the sensor cell is supported with a predetermined distance from the elastic floor via the pressure receiving support portion fitted to, and the back surface side of the sensor cell is covered with a skin member from above. As a result, the electrical connection between the wiring board and the sensor cell does not come off due to a small grasping object as in the conventional case,
The reliability is improved and the step of bonding the elastic floor and the sensor cell can be omitted.

Further, since the wiring board and the elastic floor are integrated, the thickness of the pressure sensor can be made thinner than that of the conventional one, and the flexible and accurate grasping force can be detected with reliability. It became possible to provide a pressure sensor.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of the configuration of the pressure sensor of the present invention, FIG. 2 is a perspective view showing an array of the pressure sensor according to the present invention, and FIG. 3 is a perspective view showing an example of a conventional distributed pressure sensor. FIG. 4 is a plan view of a sensor cell to which the present invention can be applied, FIG. 5 is a sectional view of a pressure sensor of the form shown in FIG. 4, and FIG. 6 is a bridge circuit formed between strain gauges on the sensor cell. FIG. 7 is a cross-sectional view when a gripping object is gripped by a conventional pressure sensor, and FIG. 8 is a perspective view showing a bonding state of a conventional pressure sensor element with an adhesive. 1 ... Sensor cell, 2 ... Pressure receiving part, 2A ... Pressure receiving support part, 3
...... Bump electrode, 3A ...... Electrode, 4 ...... Solder land, 4A
... conductor pattern, 5 ... elastic floor, 5A ... bottomed hole, 5B ...
... Thin-walled part, 6 ... Skin material, 6A ... Skin, 6B ... Thin-walled part, 7 ... groove, 8 ... bottomed hole, 9 ... wiring board, 10 ...
Elastic floor, 11A-11D …… Semiconductor strain gauge, 12 …… Adhesive, 13 …… Grip object.

Claims (1)

[Claims] 1. A semiconductor strain gauge is provided on one surface,
A plurality of sensor cells capable of detecting a force applied from the other surface side based on the output from the semiconductor strain gauge, and a sensor cell projecting from the central portion of one surface of the sensor cell, the sensor cell corresponding to the force. A pressure receiving support portion to be supported and a bottomed hole which is arranged in a matrix and which receives the pressure receiving support portions by individually fitting the pressure receiving support portions to the opposite surface which maintains a predetermined distance from one surface of the sensor cell. An elastic floor on which a signal processing circuit connected to the plurality of sensor cells is formed; and a flexible skin member that covers the other surface of the plurality of sensor cells in common, the elastic floor and the skin member The lattice-shaped portion corresponding to the gap between the adjacent sensor cells is formed thin, and the force applied to the plurality of sensor cells from the outside through the skin member is detected. Pressure sensation sensor and said.