JP2020082301A - robot - Google Patents

Abstract

To provide a robot with less erroneous detection in a proximity sensor.SOLUTION: A robot includes: a first member; a second member connected to the first member via a joint part including a rotating shaft and relatively turning around the rotating shaft with respect to the first member; and a proximity sensor comprising a capacitance-type proximity sensor electrode provided on the second member and detecting an object on the basis of a capacitance change detected by the capacitance-type proximity sensor electrode. The capacitance-type proximity sensor electrode is positioned on a surface around the rotating shaft as a center. A length in an extending direction of the rotating shaft is constant on the surface, and an outer edge on the surface includes a perpendicular part perpendicular to the extending direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a robot.

Patent Document 1 discloses a robot including a robot arm having six axes from one axis to six axes and joints connecting these axes to each other. Such a robot may collide with a structure around it when the robot arm is operated. Therefore, in the invention described in Patent Document 1, a distance sensor is provided at a position of the robot that may collide with a surrounding structure, and whether or not the robot has approached the structure based on the detection result of the distance sensor. It is supposed to check. Specifically, the joint is provided with three distance sensors, the distance between the joint and the surrounding structure is detected, and the presence or absence of proximity is confirmed. Then, when it is confirmed that the robot has approached, by issuing an alarm or the like, it is possible to prevent the robot from colliding with the surrounding structures.

Japanese Unexamined Patent Publication No. 8-99285

However, when the distance sensor is provided at the joint, if the posture of the robot arm changes, the distance between the distance sensor and the robot arm becomes shorter, and the robot arm is mistakenly detected as an obstacle or a human body. There are challenges. As a result, the stability of the robot operation is reduced.

A robot according to an application example of the present invention includes a first member,
A second member that is connected to the first member via a joint including a rotation shaft and that rotates relative to the first member around the rotation shaft;
A proximity sensor that includes an electrode for a capacitive proximity sensor provided on the second member, and that detects an object based on a change in electrostatic capacitance detected by the electrode for a capacitive proximity sensor. Then
The capacitance type proximity sensor electrode,
Located on the surface around the rotation axis with the rotation axis as the center,
The length in the extending direction of the rotating shaft is constant on the surface,
The outer edge on the surface includes an orthogonal portion that is orthogonal to the extending direction.

FIG. 3 is a perspective view showing the robot according to the first embodiment. It is a block diagram of the robot shown in FIG. It is a disassembled perspective view which expands and shows a part of robot arm 10 shown in FIG. FIG. 4 is a perspective view showing a state where a part of the robot arm 10 shown in FIG. 3 is assembled. It is a figure for demonstrating a mode that a 2nd member rotates relatively to a 1st member around a rotation axis. It is a figure for explaining a mode that a 2nd member rotates relatively to a 1st member of a robot concerning a conventional example around a rotation axis. It is a perspective view which shows the 2nd member when it exists in the position of [A] shown in FIG. It is a perspective view which shows the 2nd member when it exists in the position of [B] shown in FIG. It is a perspective view which shows the 2nd member in the position of [C] shown in FIG. It is a perspective view which shows a part of robot which concerns on 2nd Embodiment. It is a figure for comparison and is a perspective view showing a robot arm provided with an electrode that does not satisfy at least one of the three elements a, b, and c according to the first embodiment. It is a perspective view showing a robot arm provided with an electrode that does not satisfy at least one of the three elements a, b, and c according to the first embodiment. It is a perspective view which shows the modification of 2nd Embodiment. It is a perspective view which shows the modification of 2nd Embodiment.

Hereinafter, preferred embodiments of a robot of the present invention will be described in detail with reference to the accompanying drawings.
<First Embodiment>
FIG. 1 is a perspective view showing a robot according to the first embodiment. FIG. 2 is a block diagram of the robot shown in FIG. In the following, the base 110 side of the robot 1 will be referred to as the “base end side”, and the opposite side, that is, the end effector 17 side will be referred to as the “tip side”.

The robot 1 shown in FIG. 1 is a system that uses the robot arm 10 to which the end effector 17 is attached, for example, to perform work such as material supply, material removal, conveyance, and assembly of precision equipment and components that compose the precision equipment. .. The robot 1 includes a robot arm 10 having a plurality of arms 11 to 16, an end effector 17 attached to the tip end side of the robot arm 10, and a control device 50 for controlling the operations of these. The outline of the robot 1 will be described below.

The robot 1 is a so-called 6-axis vertical articulated robot. As shown in FIG. 1, the robot 1 includes a base 110 and a robot arm 10 that rotates relative to the base 110.

The base 110 is fixed to, for example, a floor, a wall, a ceiling, a movable carriage, or the like. The robot arm 10 includes an arm 11 rotatably connected to a base 110, an arm 12 rotatably connected to the arm 11, and a rotatably connected arm 12. Arm 13, the arm 14 rotatably connected to the arm 13, the arm 15 rotatably connected to the arm 14, and the arm 15 rotatably. And an arm 16 connected thereto. In addition, a portion of the base 110 and the arms 11 to 16 that rotate two mutually connected members constitutes a “joint portion”.

Further, as shown in FIG. 2, the robot 1 includes a drive unit 130 that drives each joint of the robot arm 10, and an angle sensor 135 that detects a drive state of each joint of the robot arm 10. The drive unit 130 is configured to include, for example, a motor and a speed reducer. The angle sensor 135 includes, for example, a magnetic or optical rotary encoder.

An end effector 17 is attached to the tip surface of the arm 16 of the robot 1 as described above. A force sensor may be arranged between the arm 16 and the end effector 17.

The end effector 17 is a gripping hand that grips an object. As shown in FIG. 1, the end effector 17 includes a main body 171, a drive section 170 installed in the main body 171, a pair of grip sections 172 that are opened and closed by a drive force from the drive section 170, and a grip section 172. And a gripping force sensor 173 provided in the.

Here, the driving unit 170 is configured to include, for example, a motor and a transmission mechanism such as a gear that transmits the driving force from the motor to the pair of gripping units 172. Then, the pair of grips 172 is opened and closed by the driving force from the driving unit 170. Accordingly, the object can be held and held between the pair of grips 172, or the object held between the pair of grips 172 can be released. The gripping force sensor 173 is, for example, a resistance-type or electrostatic-type pressure-sensitive sensor, and is arranged between the gripping part 172 or the gripping part 172 and the driving part 170, and a force applied between the pair of gripping parts 172. To detect. The end effector 17 is not limited to the gripping hand described above, and may be, for example, an end effector that holds an object by suction. In this specification, “holding” is a concept including both suction and grip. Further, “adsorption” is a concept including adsorption by magnetic force, adsorption by negative pressure, and the like. Further, the number of fingers of the gripping hand used for the end effector 17 is not limited to two and may be three or more.

The control device 50 shown in FIGS. 1 and 2 has a function of controlling the drive of the robot arm 10 based on the detection result of the angle sensor 135. Further, the control device 50 has a function of determining the gripping force of the end effector 17 and changing the operating condition of the robot 1 based on the detection result of the gripping force sensor 173 and the operating condition of the robot 1. Good.

The control device 50 includes a processor 51 such as a CPU (Central Processing Unit), a memory 52 such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an I/F 53 (interface circuit). Then, the control device 50 implements processing such as control of operations of the robot arm 10 and the end effector 17, various calculations and determinations by the processor 51 appropriately reading and executing the program stored in the memory 52. The I/F 53 is configured to be communicable with the robot arm 10 and the end effector 17.

Although the control device 50 is arranged in the base 110 of the robot 1 in the drawing, the present invention is not limited to this, and may be arranged outside the base 110 or in the robot arm 10, for example. A display device including a monitor such as a display, for example, an input device such as a mouse or a keyboard may be connected to the control device 50.

In addition, the robot 1 shown in FIGS. 1 and 2 includes a force sensor 21 provided on the base end side of the robot arm 10 and between the robot arm 10 and the base 110.

The force sensor 21 is a sensor that detects an external force applied to the robot arm 10. By providing such a force sensor 21, when an external force is applied to the robot arm 10 or the end effector 17, the external force is transmitted to the force sensor 21 via the robot arm 10, and the force sensor 21 detects the magnitude of the force. The orientation can be detected.

In addition, such a force sensor 21 may be provided as needed and may be omitted.

Here, FIG. 3 is an exploded perspective view showing a part of the robot arm 10 shown in FIG. 1 in an enlarged manner. Specifically, FIG. 3 shows the arm 12 and the arm 13, and the joint portion 3 which is a connecting portion thereof. Further, FIG. 4 is a perspective view showing a state where a part of the robot arm 10 shown in FIG. 3 is assembled.

Of the robot arm 10 shown in FIG. 1, the arm 12 is provided between the arm 11 and the arm 13 as described above. The arm 13 of the robot arm 10 is provided between the arm 12 and the arm 14 as described above.

The arm 12 and the arm 13 are connected to each other via the joint portion 3 as shown in FIGS. 3 and 4. That is, the arm 13 which is the second member is connected to the arm 12 which is the first member through the joint portion 3 including the rotation shaft 32. The arm 13 is configured to rotate relative to the arm 12. Further, the joint portion 3 includes a pair of connection plates 31 and 31 arranged to face each other in the Z-axis direction, and a rotating shaft 32 extending in the Z-axis direction. The pair of connecting plates 31, 31 are arranged so as to straddle the arm 12 and the arm 13. The arm 12 and the arm 13 are sandwiched between the connecting plates 31. The rotating shaft 32 is provided so as to penetrate the pair of connecting plates 31, 31 and the arm 13, and the arm 13 rotates around the rotating shaft 32. 3 and 4, the extending direction of the rotating shaft 32 is the Z-axis direction. Further, the extending direction of the arm 12 is the X-axis direction, and the direction orthogonal to both the Z-axis direction and the X-axis direction is the Y-axis direction. The pair of connecting plates 31, 31 may be integrated with the arm 12 or may be separate members.

Further, the arm 13 includes a straight line portion 131 having a straight line shape and a circular portion 132 including an arc at an outer edge when viewed from the extending direction of the rotating shaft 32. The circular portion 132 is connected to one of the ends of the straight portion 131 in the longitudinal direction on the arm 12 side. Further, the outer edge of the circular portion 132 has an arc shape, and the center of the arc coincides with the rotating shaft 32.

FIG. 5 is a diagram for explaining a state in which the arm 13 relatively rotates about the rotation shaft 32 with respect to the arm 12 and the pair of connection plates 31, 31. Note that FIG. 5 is a view of the arm 12 and the arm 13 viewed from the extending direction of the rotating shaft 32. Further, in FIG. 5, for convenience of illustration, one of the pair of connection plates 31, 31 is not shown.

FIG. 5 illustrates an example in which the arm 13 rotates in a system in which the arm 12 is fixed. The arm 13 shown in FIG. 5 is configured to rotate right and left within a predetermined angle range around the extension direction of the arm 12. In the following description, the entire angular range in which the arm 13 can rotate is referred to as the “rotatable range”. The size of this rotatable range is not particularly limited.

The linear portion 131 of the arm 13 includes an upper surface 131a and a lower surface 131b that are orthogonal to the Z-axis direction, and side surfaces 131c and 131d that are parallel to the Z-axis direction and orthogonal to the Y-axis direction. The upper surface 131a and the lower surface 131b form a rectangle having a long axis in the X-axis direction.

On the other hand, the circular portion 132 of the arm 13 includes an upper surface 132a and a lower surface 132b orthogonal to the Z axis direction, and a side surface 132c parallel to the Z axis direction. The side surface 132c connects the outer edge of the upper surface 132a and the outer edge of the lower surface 132b. As described above, since the outer edge of the upper surface 132a and the outer edge of the lower surface 132b are arcuate, the side surface 132c is an arcuate surface that is located around the rotary shaft 32 and around the rotary shaft 32. The arc surface means a surface formed when an arc centered on the rotary shaft 32 is moved along the rotary shaft 32.

Further, the capacitance type proximity sensor electrode 41 is provided on the side surface 132c. The capacitance type proximity sensor electrode 41 is an electrode used in the capacitance type proximity sensor and is an electrode that forms an electric field. Such an electrode includes, for example, a conductive film attached on the side surface 132c. Then, based on such a change in the electrostatic capacitance detected by the electrostatic capacitance type proximity sensor electrode 41, the processing unit 42 detects the presence/absence of an object approaching the arm 13. Therefore, the proximity sensor 4 is configured by the electrostatic capacitance type proximity sensor electrode 41 and the processing unit 42.

The processing unit 42 determines the presence/absence of an object by performing a process of calculating a change amount, a change speed, or the like of the capacitance based on the change in the capacitance detected by the capacitance type proximity sensor electrode 41. The processing unit 42 may be integrated with the control device 50 described above.

Such a proximity sensor 4 is a sensor that detects the presence of an object approaching the arm 13. In other words, when the arm 13 approaches the surrounding object due to the operation of the robot 1 and the object enters the detectable range of the proximity sensor 4, the proximity sensor 4 detects the presence of the object. The detectable range of the proximity sensor 4 refers to a range in which the change can be detected when the electric field formed by the capacitance type proximity sensor electrode 41 changes due to the presence of an object. It should be noted that the objects include living bodies such as humans and animals.

When the presence of the object is detected by the proximity sensor 4, the detection signal is output to the control device 50. Then, the control device 50 can stop the operation of the robot arm 10 or operate the robot arm 10 so as to avoid contact with an object. As a result, the contact between the robot arm 10 and the object can be prevented. Further, instead of these controls, an alarm for warning the contact between the robot arm 10 and the object may be issued.

Here, FIG. 6 is a diagram for explaining a state in which the second member relatively rotates about the rotation axis with respect to the first member of the robot according to the conventional example. Note that, for convenience of explanation, in FIG. 6, components other than the differences from FIG. 5 are denoted by the same reference numerals as those in FIG.

The arm 13', which is the second member of the conventional robot arm 10' shown in FIG. 6, has a square portion 132' instead of the circular portion 132 shown in FIG. Similar to FIG. 5, the arm 13' shown in FIG. 6 is also rotatable left and right within a predetermined angle range around the extension direction of the arm 12 which is the first member. The other configurations of the robot arm 10 ′ are similar to those of the robot arm 10. The electrode 41' shown in FIG. 6 is provided on the side surface of the rectangular portion 132'.

When the arm 13 ′ rotates around the rotation shaft 32, the electrode 41 ′ also rotates relative to the arm 12 accordingly.

By the way, since the arm 12 shown in FIG. 6 is arranged near the electrode 41', it is included in the detectable range of the proximity sensor including the electrode 41'. Thereby, the arm 12 and the arm 13 can be close to each other, and the robot 1 can be easily downsized. If the arm 12 is separated from the arm 13' so as not to be included in the detectable range of the proximity sensor, the robot arm 10' becomes significantly large, which is not realistic. On the other hand, when the arm 12 is included in the detectable range of the proximity sensor including the electrode 41 ′, the distance between the electrode 41 ′ and the arm 12 changes as the electrode 41 ′ rotates. Such a change in distance reduces the accuracy of the original function of detecting the presence of an object. That is, as a result of the change in the distance between the electrode 41′ and the arm 12, it is erroneously recognized that there is an object in the detectable range of the proximity sensor, and the measurement accuracy of the distance to the object is high. May decrease.

Hereinafter, a specific example of this problem will be described. As shown in FIG. 6, when the arm 13' is in the position [A], the shortest distance between the electrode 41' and the arm 12 is L1. Further, when the arm 13' is rotated from the position [A] to the position [B], the shortest distance between the electrode 41' and the arm 12 is L2. Further, when the arm 13' is rotated from the position [A] to the position [C], the shortest distance between the electrode 41' and the arm 12 is L3.

Since the electrode 41' is provided on the side surface of the rectangular portion 132', when the arm 13' rotates, the shortest distance between the electrode 41' and the arm 12 changes. That is, the shortest distance L1 and the shortest distances L2 and L3 are different. As a result, the electrostatic capacitance detected by the electrode 41' changes unintentionally as the arm 13' rotates. Such a change causes the proximity sensor 4 to erroneously recognize that there is an object near the robot arm 10'.

Therefore, in the present embodiment, as shown in FIG. 5, a circular portion 132 is used instead of the rectangular portion 132'. The capacitance type proximity sensor electrode 41 is provided on the side surface 132c of the circular portion 132. Hereinafter, the capacitance type proximity sensor electrode 41 according to the present embodiment will be described in detail.

The capacitance type proximity sensor electrode 41 according to the present embodiment satisfies the following three elements a, b and c.

a: the capacitance type proximity sensor electrode 41 is provided on the side surface 132c which is an arc surface centered around the rotation shaft 32 and which is located around the rotation shaft 32. b: the capacitance type proximity sensor electrode. 41, the length in the extending direction (Z-axis direction) of the rotating shaft 32 is constant on the side surface 132c (arc surface) c: The outer edge of the capacitance type proximity sensor electrode 41 is the rotating shaft 32. Including a portion orthogonal to the extending direction (Z-axis direction)

The three elements a, b, and c will be sequentially described below.
First, the element a will be described. As shown in FIGS. 3 to 5, the capacitance type proximity sensor electrode 41 is provided on the side surface 132c. As described above, the side surface 132c is an arcuate surface centered on the rotating shaft 32 and positioned around the rotating shaft 32. That is, the side surface 132c shown in FIG. 5 is a side surface of a cylinder having the rotation shaft 32 as a central axis and a bottom surface of a perfect circle. Therefore, the capacitance type proximity sensor electrode 41 provided on the side surface 132c also forms a part of a cylinder having the rotating shaft 32 as its central axis. Therefore, even if the arm 13 rotates about the rotation shaft 32, the shortest distance between the capacitance type proximity sensor electrode 41 and the arm 12 does not change. As a result, the element a is one of the elements that minimizes the change in capacitance due to the rotation of the capacitance type proximity sensor electrode 41.

The cylinder having the rotation shaft 32 as the central axis and the bottom surface being a perfect circle is a concept that allows a deviation of a manufacturing error from a perfect perfect circle. An example of the deviation of the manufacturing error is that the deviation from the perfect circle is 10% or less of the radius of the perfect circle.

Next, the element b will be described. The length of the capacitance type proximity sensor electrode 41 in the Z-axis direction is constant on the side surface 132c. Specifically, as shown in FIG. 3, when the lengths in the Z-axis direction of the capacitance type proximity sensor electrode 41 at arbitrary two positions on the side surface 132c are L4 and L5, the length L4 is The length L5 is equal to each other. When the capacitance type proximity sensor electrode 41 that fills the element b rotates, the positional relationship between the electric force lines generated from the capacitance type proximity sensor electrode 41 and the arm 12 does not easily change. As a result, the element b is also one of the elements that minimizes the change in capacitance due to the rotation of the capacitance-type proximity sensor electrode 41.

In addition, that the length in the Z-axis direction of the capacitance type proximity sensor electrode 41 is constant on the side surface 132c means that the total length in the Z-axis direction does not change in the entire length of the side surface 132c in the circumferential direction. A deviation of about manufacturing error is allowed. An example of the deviation of the manufacturing error is that the difference between the maximum value and the minimum value in the Z-axis direction is 10% or less of the maximum value.

Next, the element c will be described. The outer edge of the capacitance type proximity sensor electrode 41 includes an orthogonal portion 411 orthogonal to the Z-axis direction, as shown in FIG. Since the orthogonal portion 411 is orthogonal to the extending direction of the rotating shaft 32, even if the arm 13 rotates around the rotating shaft 32, the position of the capacitive proximity sensor electrode 41 in the Z-axis direction is It does not change. Therefore, the positional relationship between the electric force line generated from the capacitance type proximity sensor electrode 41 and the arm 12 is unlikely to change. As a result, the element c is also one of the elements that minimizes the change in capacitance due to the rotation of the capacitance type proximity sensor electrode 41.

Note that the orthogonal portion 411 is orthogonal to the Z-axis direction, which means that the orthogonal portion 411 is located on a plane having the rotating shaft 32 as a normal line. This is a concept that allows a degree of deviation. An example of the deviation of the manufacturing error is that the intersection angle between the orthogonal portion 411 and the Z-axis direction is within a range of 90°±5°.

By satisfying the above three elements a, b, and c, even if the electrostatic capacitance type proximity sensor electrode 41 rotates, the change in the electrostatic capacitance detected by the electrostatic capacitance type proximity sensor electrode 41 does not occur. It can be kept to a minimum. As a result, an unintended change in the capacitance is suppressed, so that it is possible to prevent frequent erroneous detection by the proximity sensor 4. That is, it is possible to realize the robot 1 with few false detections in the proximity sensor 4.

As described above, the robot 1 according to the present embodiment is connected to the arm 12 as the first member and the arm 12 via the joint portion 3 including the rotation shaft 32, and the rotation shaft 32 is connected to the arm 12. An arm 13 that is a second member that relatively rotates around and an electrode 41 for a capacitance type proximity sensor provided on the arm 13 are provided, and the electrostatic capacitance detected by the electrode 41 for a capacitance type proximity sensor is provided. The proximity sensor 4 detects an object based on a change in capacity. Then, the capacitance type proximity sensor electrode 41 is located on a surface around the rotation shaft 32, that is, a side surface 132c which is an arc surface, and the extension of the rotation shaft 32. An orthogonal portion 411 whose length in the present direction is constant on the side surface 132c around the rotating shaft 32 and whose outer edge on the side surface 132c around the rotating shaft 32 is orthogonal to the extending direction of the rotating shaft 32. Is included.

According to such a robot 1, even if the capacitance type proximity sensor electrode 41 also rotates with the rotation of the arm 13, the capacitance detected by the capacitance type proximity sensor electrode 41 is reduced. Change can be minimized. As a result, an unintended change in electrostatic capacitance is suppressed, so that it is possible to realize the robot 1 with few false detections in the proximity sensor 4.

It should be noted that when the object is not within the detectable range of the proximity sensor 4, the change in the capacitance due to the rotation of the arm 13 should be as small as possible. The change width is preferably less than 10% of the maximum value of the capacitance. Such a characteristic suppresses an unintended change in electrostatic capacitance due to the rotation of the arm 13, contributes to the realization of a highly reliable robot 1 with few false detections in the proximity sensor 4.

Further, the capacitance type proximity sensor electrode 41 according to the present embodiment is a planar electrode attached on the side surface 132c. Although a part of the outer edge of the capacitance type proximity sensor electrode 41 is the orthogonal portion 411 orthogonal to the Z-axis direction as described above, the orthogonal portion 411 is provided over the entire length of the side surface 132c which is an arc surface. ing. In other words, the orthogonal portion 411 is orthogonal to the extending direction of the rotating shaft 32 over the entire length of the side surface 132c.

Since the orthogonal portion 411 is provided in such a range, even if the arm 13 rotates, the capacitance type proximity sensor electrode 41 in the entire rotatable range of the arm 13 as shown in FIG. It becomes difficult for the positional relationship between the line of electric force generated from the arm 12 and the arm 12 to change. Therefore, regardless of the size of the rotatable range, it is possible to realize the robot 1 with few false detections in the proximity sensor 4.

The total length of the side surface 132c means the total length in the circumferential direction on the side surface 132c, which is an arc surface, that is, in the plane orthogonal to the Z-axis direction.

On the other hand, in the robot 1 according to the present embodiment, the capacitance type proximity sensor electrode 41 may satisfy the following element d instead of the above three elements a, b and c.

d: The capacitive proximity sensor electrode 41 can detect the proximity sensor 4 from the surface of the arm 12 when the second member arm 13 relatively rotates with respect to the first member arm 12. The area of the area CA intersecting the virtual space VS at a distance is constant.

That is, the robot 1 according to the present embodiment is connected to the arm 12 as the first member and the arm 12 via the joint portion 3 including the rotation shaft 32, and is relatively movable around the rotation shaft 32 with respect to the arm 12. The arm 13 that is a second member that rotates mechanically and the electrostatic proximity sensor electrode 41 provided on the arm 13 are provided, and the capacitance detected by the electrostatic proximity sensor electrode 41 changes. The proximity sensor 4 detects an object based on the. When the arm 13 rotates relative to the arm 12, the electrostatic capacitance type proximity sensor electrode 41 intersects the virtual space VS, which is at the detectable distance of the proximity sensor 4 from the surface of the arm 12. The element d that the area of the existing area CA is constant is satisfied. The detectable distance of the proximity sensor 4 refers to the maximum distance at which the presence of the object can be detected based on the change in the capacitance when the object approaches the capacitance type proximity sensor electrode 41. ..

According to such a robot 1, even if the capacitance type proximity sensor electrode 41 also rotates with the rotation of the arm 13, the capacitance detected by the capacitance type proximity sensor electrode 41 is reduced. Change can be minimized. As a result, an unintended change in electrostatic capacitance is suppressed, so that it is possible to realize the robot 1 with few false detections in the proximity sensor 4.

The element d will be described below.
As described above, the arm 12 provided at the position facing the capacitance type proximity sensor electrode 41 is located in the detectable range of the proximity sensor 4. This means that, from a different perspective, when the virtual space VS located at the detectable distance of the proximity sensor 4 from the surface of the arm 12 is virtualized, at least a part of the capacitance type proximity sensor electrode 41 is present in the virtual space VS. In other words, it is included. In this case, in the capacitance type proximity sensor electrode 41, the region CA intersecting the virtual space VS is a region where the lines of electric force generated from the region CA are affected by the arm 12. In FIG. 5, dots are added to an example of the virtual space VS. The virtual space VS refers to a set of points located within the detectable distance of the proximity sensor 4 from the surface of the arm 12. Note that the virtual space VS in FIG. 5 illustrates only a part located on the arm 13 side for convenience of illustration. That is, the actual virtual space extends over the entire surface of the arm 12. The portion of the capacitance type proximity sensor electrode 41 that intersects with, or is in contact with, the virtual space VS is the above-described area CA.

Therefore, in the element d, the area of the region CA that intersects the virtual space VS at the detectable distance of the proximity sensor 4 from the surface of the arm 12 is the arm that is the second member with respect to the arm 12 that is the first member. When 13 rotates relatively, it is constant without changing. Specific examples of the element d will be described with reference to FIGS. 7 to 9.

7 to 9 are views for explaining the manner in which the arm 13 as the second member relatively rotates about the rotation shaft 32 with respect to the arm 12 as the first member. 7 is a perspective view showing the arm 13 at the position [A] shown in FIG. 5, and FIG. 8 is a perspective view showing the arm 13 at the position [B] shown in FIG. FIG. 9 is a perspective view showing the arm 13 at the position [C] shown in FIG. 5. In FIGS. 7 to 9, sparse dots are provided on the capacitance type proximity sensor electrode 41, and dense dots are provided on the area CA.

As shown in FIGS. 7 to 9, as the arm 13 relatively rotates with respect to the arm 12, the capacitance type proximity sensor electrode 41 moves relative to the virtual space VS associated with the arm 12. Move. At that time, by satisfying the element d, the areas of the regions CA are the same whether the arm 13 is in the position [A], the position [B], or the position [C]. become. That is, the shape of the capacitance type proximity sensor electrode 41 and the positional relationship between the capacitance type proximity sensor electrode 41 and the arm 12 are appropriately adjusted so that the area CA does not change. As a result, even if the capacitance type proximity sensor electrode 41 rotates, the state of interaction between the electric force lines generated from the capacitance type proximity sensor electrode 41 and the arm 12 is unlikely to change. Therefore, even if the capacitance type proximity sensor electrode 41 rotates, the change in capacitance can be minimized. As a result, an unintended change in the electrostatic capacitance is suppressed, so that it is possible to realize the robot 1 with few false detections in the proximity sensor 4.

Note that the area of the area CA is constant means that when the arm 13 relatively rotates with respect to the arm 12, the difference between the maximum value and the minimum value of the area CA is 10% or less of the maximum value. There is something.

Further, when the arm 13 which is the second member relatively rotates with respect to the arm 12 which is the first member, the shape may change as long as the area of the area CA is constant, but the shape is also preferable. To be constant. As a result, even if the capacitance type proximity sensor electrode 41 rotates, the state of interaction between the arm 12 and the line of electric force generated from the capacitance type proximity sensor electrode 41 is unlikely to change. Therefore, even if the capacitance type proximity sensor electrode 41 rotates, the change in capacitance can be suppressed to a minimum. That is, although the change in the capacitance of the area CA has a great influence on the change in the capacitance, the shape of the area CA also has some influence. Therefore, by making not only the area but also the shape of the region CA constant, the change in capacitance can be suppressed to a minimum.

Further, when the arm 13 that is the second member rotates relative to the arm 12 that is the first member, the relative position of the area CA with respect to the arm 12 may change, but the relative position is preferably constant. Is. As a result, even if the electrostatic capacitance type proximity sensor electrode 41 rotates, the state of interaction between the electric force lines generated from the electrostatic capacitance type proximity sensor electrode 41 and the arm 12 becomes further difficult to change. Therefore, even if the capacitance type proximity sensor electrode 41 rotates, the change in capacitance can be suppressed to a minimum.

The relative position of the area CA with respect to the arm 12 refers to the position of the area CA in the visual field fixed to the arm 12. Therefore, for example, it is sufficient that the position of the area CA in the field of view fixed to the arm 12 does not change in the process of rotating the arm 13 with respect to the fixed arm 12.

Although the first embodiment has been described above, the capacitance type proximity sensor electrode 41 may be provided not on the arm 13 but on the arm 12, the arm 15 or the like shown in FIG. There may be more than one.

Further, the proximity sensor 4 may further have electrodes other than the capacitance type proximity sensor electrode 41 described above. For example, the capacitance type proximity sensor electrode 41 shown in FIGS. 3 and 4 also extends to the surface of the linear portion 131 of the arm 13, so that the presence of an object close to the linear portion 131. Can be detected.

The arrangement of such electrodes is appropriately set according to the range of motion of the robot arm 10 and the operating environment of the robot 1, and is not limited to the illustrated arrangement and may be any arrangement.

Further, the capacitance type proximity sensor electrode 41 may satisfy the element d together with the above three elements a, b and c.

<Second Embodiment>
FIG. 10 is a perspective view showing a part of the robot according to the second embodiment.

Hereinafter, the second embodiment will be described focusing on the differences from the above-described embodiment, and the description of the same matters will be omitted. In FIG. 10, the same components as those in the above-described first embodiment are designated by the same reference numerals.

The second embodiment is the same as the first embodiment except that it is provided with a plurality of electrostatic capacitance type proximity sensor electrodes 41. That is, the capacitance type proximity sensor electrode 41 shown in FIG. 10 has a first electrode 41a and a second electrode 41b. By including the capacitive proximity sensor electrode 41 divided into a plurality of pieces in this way, it is possible to further improve the detection accuracy of the object in the proximity sensor 4.

The detection method of the proximity sensor 4 including the electrostatic capacitance type proximity sensor electrode 41 divided into a plurality may be either a self-capacitance method or a mutual capacitance method. Among them, in the mutual capacitance type proximity sensor 4, one of the first electrode 41a and the second electrode 41b described above is used as an electrode for generating an electric force line, and the other is used as a capacitance measuring electrode. In the case of the self-capacitance method, the measurement capacity increases both when the distance from the object is shortened and when foreign matter with a high dielectric constant such as water droplets adheres to the sensor electrode. It is difficult. However, in the case of the mutual capacitance method, the lines of electric force are blocked by an object in the vicinity and do not reach the electrode for measuring the capacitance, and the proximity of the object is detected because the measurement capacitance decreases. Even if foreign matter such as water drops adheres to the working electrode 41, it is possible to continuously detect the change in capacitance. Therefore, the mutual capacitance type proximity sensor 4 tends to maintain the original function of detecting the presence of an object. As a result, it is possible to realize the robot 1A in which erroneous detection by the proximity sensor 4 is particularly small.

Here, even when divided in this way, the first electrode 41a and the second electrode 41b respectively satisfy the three elements a, b, c, or the element d according to the first embodiment. Therefore, also in the present embodiment, similarly to the first embodiment, even if the capacitance type proximity sensor electrode 41 rotates, the change in the capacitance detected by the capacitance type proximity sensor electrode 41. It is possible to realize the robot 1</b>A in which the erroneous detection by the proximity sensor 4 is minimized.

In FIG. 10, as an example, the first electrode 41a and the second electrode 41b electrically insulated from each other are arranged in the Z-axis direction. In other words, the first electrode 41a and the second electrode 41b shown in FIG. 10 are obtained by dividing the capacitance type proximity sensor electrode 41 shown in FIG. 3 into two in the Z-axis direction. The gap between the first electrode 41a and the second electrode 41b extends in the direction orthogonal to the Z-axis direction. Therefore, each of the first electrode 41a and the second electrode 41b has two outer edges that are orthogonal to the Z-axis direction, but these outer edges are also orthogonal to the Z-axis direction. The arrangement of the plurality of electrodes is not limited to this, and may be any arrangement.

11 and 12 are diagrams for comparison, respectively, and show a robot arm provided with electrodes that do not satisfy at least one of the three elements a, b, and c according to the first embodiment. It is a perspective view. Note that, in FIGS. 11 and 12, for convenience of description, the same components as those in FIG. 10 are denoted by the same reference numerals.

The electrode 410' shown in FIG. 11 is divided into two, a first electrode 41a' and a second electrode 41b', which are similar to the first electrode 41a and the second electrode 41b except that their shapes are different. is there. Specifically, the outer edge of the first electrode 41a′ does not have the orthogonal portion 411 described above, but instead has the non-orthogonal portion 411′ that obliquely intersects the Z-axis direction. There is. That is, of the outer edge of the first electrode 41a', the two non-orthogonal portions 411' intersecting in the Z-axis direction are inclined so as to be displaced in the Z-axis direction shown in FIG. Therefore, the outer edge of the first electrode 41a' shown in FIG. 11 does not satisfy the element c described above.

The outer edge of the second electrode 41b′ has an orthogonal portion 411 that intersects the Z-axis direction, but in addition to that, it has a non-orthogonal portion 411′ that obliquely intersects the Z-axis direction. is doing. That is, of the outer edge of the second electrode 41b′ shown in FIG. 11, the portion located on the negative side of the Z axis is the orthogonal portion 411, while the portion located on the positive side of the Z axis is the non-orthogonal portion 411′. It has become. Therefore, the outer edge of the second electrode 41b' shown in FIG. 11 does not satisfy the elements b and c described above.

Since the robot shown in FIG. 11 is provided with the electrode 410′ as described above, when the electrode 410′ rotates, the positional relationship between the electric force line generated from the electrode 410′ and the arm 12 changes. .. Therefore, the capacitance may change.

Further, the robot shown in FIG. 11 described above does not satisfy the element d according to the first embodiment. Therefore, also from this viewpoint, in the robot shown in FIG. 11, the electrostatic capacitance may change.

On the other hand, the electrode 410′ shown in FIG. 12 is divided into three parts, a first electrode 41c′, a second electrode 41d′, and a third electrode 41e′, but these are different in shape, but the first electrode 41a. And the same as the second electrode 41b. Specifically, the first electrode 41c′, the second electrode 41d′, and the third electrode 41e′ each have a substantially rectangular shape having a long axis in the Z-axis direction, and are arranged side by side around the rotation shaft 32. There is. Therefore, such an electrode 410 ′ has a shape in which a position where the electrode is present around the rotation shaft 32 and a position where the electrode is not present are mixed. Therefore, the electrode 410' shown in FIG. 12 does not satisfy the element b described above because the length in the Z-axis direction is not constant on the side surface of the circular portion 132. As a result, in the robot shown in FIG. 12, when the electrode 410 ′ rotates, the positional relationship between the electric force line generated from the electrode 410 ′ and the arm 12 changes. Therefore, the capacitance may change.

Further, the robot shown in FIG. 12 described above does not satisfy the element d according to the first embodiment. Therefore, also from this point of view, the electrostatic capacitance may change in the robot shown in FIG.

From the above, the robot arm shown in FIGS. 11 and 12 cannot achieve the effects of the robots 1 and 1A according to the present embodiment.

On the other hand, the first electrode 41a and the second electrode 41b shown in FIG. 10 respectively satisfy the three elements a, b, c or the element d according to the first embodiment. In particular, the gap separating the first electrode 41a and the second electrode 41b extends so as to be orthogonal to the Z-axis direction, and as a result, two first electrodes 41a and two second electrodes 41b are provided. It has an orthogonal portion 411. With such a capacitance type proximity sensor electrode 41, even if it rotates, it is possible to obtain the effect that the change in capacitance detected by the capacitance type proximity sensor electrode 41 can be minimized. Be done. The robot 1A shown in FIG. 10 described above also satisfies the element d according to the first embodiment. Therefore, also from this point of view, the robot 1A shown in FIG. 10 has the above-described effects.

On the other hand, FIG. 13 and FIG. 14 are perspective views showing modified examples of the second embodiment. 13 and 14 show the same thing except that the angles of the visual fields in the perspective views are different from each other. Further, in FIGS. 13 and 14, for convenience of description, the same configurations as those in FIG. 10 are denoted by the same reference numerals.

The capacitance type proximity sensor electrode 41 according to the modification shown in FIGS. 13 and 14 includes a comb-teeth-shaped first electrode 41A and a second electrode 41B configured to mesh with each other. This is the same as the capacitance type proximity sensor electrode 41 shown in FIG.

Specifically, the first electrode 41A has a comb-teeth shape including three portions 412A extending around the rotation shaft 32 and a portion 413A extending in the Z-axis direction so as to connect them to each other. Is playing. On the other hand, the second electrode 41B also has a comb tooth shape including two portions 412B extending around the rotation shaft 32 and a portion 413B extending in the Z-axis direction so as to connect them to each other. There is. Then, the first electrode 41A and the second electrode 41B mesh with each other. That is, the three portions 412A and the two portions 412B are both provided on the side surface 132c of the circular portion 132, and are alternately arranged on the side surface 132c in the Z-axis direction.

These three portions 412A and two portions 412B respectively satisfy the three elements a, b, c or the element d according to the first embodiment.

By including the comb-shaped first electrode 41A and second electrode 41B, the capacitance type proximity sensor electrode 41 allows the first electrode 41A and the second electrode 41B to be sufficiently close to each other. , Can occupy a large area. Therefore, even if the area of the side surface 132c is large, the detection accuracy of the proximity sensor 4 can be improved.
Even in such a modification, the same effect as that of the second embodiment can be obtained.

The robot of the present invention has been described above based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part may be replaced with an arbitrary configuration having the same function. You can Moreover, other arbitrary components may be added to the present invention.

Further, the present invention may be a combination of the configurations of the two embodiments described above.
The robot of the present invention is not limited to a single-arm robot as long as it has a robot arm, and may be another robot such as a double-arm robot or a scalar robot. Further, the number of arms included in the robot arm is not limited to the number in the above-described embodiment, and may be 1 or more and 5 or less or 7 or more.

1... Robot, 1A... Robot, 3... Joint part, 4... Proximity sensor, 10... Robot arm, 10'... Robot arm, 11... Arm, 12... Arm, 13... Arm, 13'... Arm, 14... Arm, 15... Arm, 16... Arm, 17... End effector, 21... Force sensor, 31... Connection plate, 32... Rotating shaft, 41... Electrode for capacitance type proximity sensor, 41'... Electrode, 41A... First electrode , 41B... Second electrode, 41a... First electrode, 41a'... First electrode, 41b... Second electrode, 41b'... Second electrode, 41c'... First electrode, 41d'... Second electrode, 41e'... 3rd electrode, 42... Processing part, 50... Control device, 51... Processor, 52... Memory, 53... I/F, 110... Base, 130... Drive part, 131... Straight part, 131a... Top surface, 131b... Bottom surface , 131c... Side surface, 131d... Side surface, 132... Circular portion, 132'... Square portion, 132a... Top surface, 132b... Bottom surface, 132c... Side surface, 135... Angle sensor, 170... Drive portion, 171... Main body, 172... Gripping portion , 173... Gripping force sensor, 410'... Electrode, 411... Orthogonal part, 411'... Non-orthogonal part, 412A... Part, 412B... Part, 413A... Part, 413B... Part, CA... Region, L1... Shortest distance, L2 ...Shortest distance, L3...shortest distance, L4...length, L5...length, VS...virtual space

Claims (7)

A first member,
A second member that is connected to the first member via a joint including a rotation shaft and that rotates relative to the first member around the rotation shaft;
A proximity sensor that includes an electrode for a capacitive proximity sensor provided on the second member, and that detects an object based on a change in electrostatic capacitance detected by the electrode for a capacitive proximity sensor. Then
The capacitance type proximity sensor electrode,
Located on the surface around the rotation axis with the rotation axis as the center,
The length in the extending direction of the rotating shaft is constant on the surface,
An outer edge on the surface includes an orthogonal portion that is orthogonal to the extending direction,
A robot characterized by that. The robot according to claim 1, wherein the orthogonal portion is orthogonal to the extending direction in the entire length of the surface in the circumferential direction. A first member,
A second member that is connected to the first member via a joint including a rotation shaft and that rotates relative to the first member around the rotation shaft;
A proximity sensor that includes an electrode for a capacitive proximity sensor provided on the second member, and that detects an object based on a change in electrostatic capacitance detected by the electrode for a capacitive proximity sensor. Then
The capacitance type proximity sensor electrode is provided in a virtual space at a distance detectable by the proximity sensor from the surface of the first member when the second member rotates relative to the first member. A robot characterized in that the area of the intersecting regions is constant. The robot according to claim 3, wherein the shape of the region is constant when the second member rotates relative to the first member. The robot according to claim 3, wherein a relative position of the region with respect to the first member is constant when the second member relatively rotates with respect to the first member. The robot according to claim 1, wherein the capacitance type proximity sensor electrode is divided into a plurality of parts. The robot according to claim 6, wherein a detection method of the proximity sensor is a mutual capacitance method.

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