JP2004066364A - Compliance mechanism - Google Patents

Abstract

An object of the present invention is to keep the joint mechanism of a hand small and light while keeping the size of the displacement of the elastic displacement element, the magnitude of the force applied thereto, and the magnitude of the impact regardless of the magnitude of the impact. Provided are a joint mechanism capable of accurately detecting a magnitude and a mechanism for detecting a magnitude of a force acting on an elastic displacement element.
A movable member (11) fixed to a hand and a fixed member (15) fixed to a robot arm are directly or indirectly moved by elastic displacement elements (13a, 13b, 16a, 16b) which perform elastic displacement with one degree of freedom by an external force. The elastic displacement elements 13a, 13b, 16a, 16b are connected between the elastic displacement elements 13a, 13b, 16a, 16b and the movable member 11, or between the elastic displacement elements 13a, 13b, 16a, 16b and the fixed member 15. A force measuring means for measuring the magnitude of the reaction force received from the device is provided.
[Selection diagram] Fig. 1

Description

[0001]
[Industrial applications]
The present invention relates to a joint mechanism for connecting a hand used for assembling or disassembling a product to a robot arm, and more particularly to a compliance device for a robot that performs assembling and disassembling operations while receiving a force from a part to be assembled or removed. In addition, the magnitude of the reaction force acting on the hand at the time of compliance can be easily detected to prevent incomplete compliance or damage to components due to the incomplete compliance.
[0002]
[Prior art]
When assembling or disassembling work by gripping parts with the hand provided at the end of the robot arm, if the robot does not have compliance, the dimensions of parts and positioning of parts are high in order to perform the above work reliably. Since precision is required, the cost of parts is increased, the work speed of assembly and disassembly is reduced, the work efficiency is significantly reduced, and the work failure rate is increased. For this reason, a compliance (adaptation) characteristic by an elastic mechanism is given to a connection portion between the robot arm (hereinafter, referred to as an “arm”) and the hand or a finger portion of the hand. The method of providing compliance (adaptation) characteristics includes a method of displacing the elastic mechanism by a work reaction force at the time of assembling or disassembling work to adjust the positions and postures of the parts. A method of providing a force sensor for detecting a force and controlling the arm based on the detected work reaction force to appropriately adjust the hand position and posture to more accurately match the position and posture of the parts. There is.
[0003]
FIG. 7A shows a generally used compliance mechanism. In this embodiment, the hand-side plate 51 and the arm-side plate 52 are connected by an elastic member 53. When the robot arm 54 performs an assembling operation, if there is a deviation in the relative position or posture between the fitting part 56 and the fitting part 57 held by the hand 55, these parts come into contact with each other and have a size. An external force is applied to the hand 55. Due to this external force, the elastic member 53 is elastically deformed, whereby the deviation of the relative position and posture between the fitting part 56 and the fitting part 57 is compensated, and the assembling work is performed. However, when the relative position deviation amount of the component is larger than the allowable deformation amount of the elastic member, or when the strength of the component is small, the relative position deviation cannot be compensated for, and the predetermined work is not accurately performed, Alternatively, the parts may be damaged due to the large external force.
[0004]
In addition to the above-mentioned compliance mechanism, a force sensor is provided at a connection portion between the arm and the hand to detect the magnitude of the work reaction force, so that a translation force or a moment other than the direction expected at the time of work is not generated. In some cases, a compliance mechanism and a force sensor 58 are provided between the hand and the arm to control the arm (FIG. 7B). However, in this case, since the compliance mechanism and the force sensor 58 are individually arranged in the vertical direction between the hand and the arm, the distance from the arm to the tip of the hand increases, and the weight increases. High-speed, high-precision operation becomes difficult.
As a method of providing a compliance mechanism and a force sensor that is thin in the Z-axis direction, there is Japanese Patent Application Laid-Open No. Hei 5-253883, “XY-θZ-axis leaf spring compliance mechanism”, which has the following problems. is there.
[0005]
In this prior art, as shown in FIG. 9, four leaf springs 72 having the same outer shape and rigidity are formed into a square lattice by four rotating links 74 having a rotation axis parallel to the surface of the leaf spring. The movable rigid body 76 is fixed between the pair of leaf springs so as to bridge to the midpoint of each leaf spring 72 between the pair of leaf springs which are connected to each other by the short sides so as to face each other. By fixing the other pair of leaf springs 72 to the stationary rigid body 80 at the midpoint of each leaf spring, between the movable rigid body 76 and the stationary rigid body 80, mutually orthogonal X-axes perpendicular to the surface of the leaf spring and Compliance is provided in the Y-axis direction and the rotation direction of the Z-axis orthogonal to the X-axis and the Y-axis. Further, by appropriately attaching a strain gauge to the leaf spring 72 and forming a bridge circuit, the forces in the X and Y axis directions and the moment around the Z axis are detected independently.
[0006]
However, in the above-mentioned conventional method, since the allowable displacement range of the strain gauge is small, the displacement amount of the leaf spring must be reduced, so that the displacement amount of mechanical compliance cannot be increased. There is a risk of breaking the strain gauge, and it is difficult to operate the hand at high speed to avoid breaking the strain gauge.
[0007]
[Problem to be solved]
The present invention relates to a joint mechanism for a robot and a hand that performs assembly and disassembly operations while receiving a reaction force from a part and has a force sensing function for detecting a force applied in compliance. It is intended to be able to increase the accuracy and to reduce the size and weight,
While keeping the joint mechanism of the hand small and lightweight, regardless of the magnitude of the displacement of the elastic displacement element, the magnitude of the force applied to it, and the magnitude of the impact, the displacement of the elastic displacement element and the magnitude of the force applied to this An object of the present invention is to devise a mechanism for detecting the magnitude of the force applied to the joint mechanism and the elastic displacement element so that the detection can be performed accurately.
[0008]
[Measures taken to solve the problem]
[Solution 1] (corresponding to claim 1)
Means 1 for solving the above problem 1 is based on the following (a) and (b) on the premise of a joint mechanism for connecting a hand and a robot arm.
(A) The movable member fixed to the hand and the fixed member fixed to the robot arm are directly or indirectly connected to each other by an elastic displacement element that performs elastic displacement of one degree of freedom by an external force,
(B) A force measuring means for measuring the magnitude of the reaction force received from the elastic displacement element is provided between the elastic displacement element and the movable member, or between the elastic displacement element and the fixed member.
[0009]
[Action]
A movable member fixed to the hand and a fixed member fixed to the robot arm are connected by an elastic displacement element having one degree of elastic displacement, and fixed between the elastic displacement element and the movable member or between the elastic displacement element and the movable member. Since at least one of the members is provided with force measuring means for measuring the magnitude of the reaction force received from the elastic displacement element, the force measuring means incorporated in the joint mechanism by the elastic displacement element is provided with an elastic displacement element. Is detected as the pressing force, and the magnitude can be accurately detected regardless of the magnitude of the force applied to the elastic displacement element and the magnitude of the distortion of the elastic displacement element. Moreover, the force measuring means is compactly incorporated in the joint mechanism.
Therefore, a compact and lightweight compliance device having a force sensing function and capable of high-precision work is configured.
The “indirect connection” means that the movable member and the fixed member are connected via the intermediate member by the elastic displacement element.
[0010]
Embodiment 1 (corresponding to claim 2)
In the first embodiment, the force measuring means of the solving means 1 is a piezoelectric material sandwiched between the elastic displacement element and the movable member or the fixed member, and a potential measuring means for detecting a potential of the piezoelectric material is provided. A force calculating means for calculating a force acting on the piezoelectric material from an output of the measuring means is provided.
[0011]
[Action]
Since the force applied to the elastic displacement element is received by the piezoelectric material sandwiched between the elastic displacement element and the movable member or the fixed member, and this is electrically detected by the potential measuring means and the force calculating means, the force is applied. Since the measuring means is extremely compactly incorporated into the joint mechanism, the compliance device provided with the force measuring means is small and lightweight.
[0012]
Embodiment 2 (corresponding to claim 3)
The second embodiment is provided with a displacement calculating means for calculating the displacement of the elastic displacement element from the output value of the force measuring means of the solving means 1.
[0013]
(Solution 2) (corresponding to claim 4)
Solution 2 is based on the following (a) and (b) on the premise of a joint mechanism for connecting the hand and the robot arm.
(A) The movable member fixed to the hand and the fixed member fixed to the robot arm are directly or indirectly connected to each other by an elastic displacement element that performs elastic displacement of one degree of freedom by an external force,
(B) Displacement measuring means for measuring the displacement of the elastic displacement element is provided.
The above-mentioned "displacement amount measuring means" does not detect the amount of displacement of the elastic displacement element with a strain gauge, but means means for directly measuring the amount of displacement itself with a potentiometer or the like. "Connecting" means that the movable member and the fixed member are connected via the intermediate member by the elastic displacement element.
[0014]
[Action]
Since the displacement amount of the elastic displacement element, that is, the relative displacement amount between the movable member and the fixed member connected via the elastic displacement element is detected by a displacement amount measuring means such as a potentiometer, Regardless of the magnitude of the displacement of the elastic displacement element and the magnitude of the force acting on the elastic displacement element, the amount of displacement can be accurately detected, and the measurement accuracy is determined by the magnitude of the force acting on the elastic displacement element. Is not affected.
Since the displacement amount is detected by the displacement amount measuring means as an electric quantity, by comparing this with a reference value, it is determined that the force applied to the elastic displacement element has exceeded the allowable limit value. Control such as an emergency stop of the robot hand can be performed, and the detected amount can be compared with a reference value to control the robot so as not to exceed the allowable limit.
[0015]
Embodiment 3 (corresponding to claim 5)
A third embodiment is that the solving means 2 has a force calculating means for calculating the magnitude of the force acting on the elastic displacement element from the output value of the displacement measuring means.
[0016]
[Action]
Since the output value of the displacement measuring means is converted into the magnitude of the force by the force calculating means, the detected data can be fed back to control the posture, position, and the like of the robot hand.
[0017]
[Solution 3] (corresponding to claim 6)
A third solution is that the elastic displacement element in the first solution and the second solution has a leaf spring structure in which a thin band-shaped metal plate is bent like a saw blade.
[0018]
[Action]
Since the elastic displacement element has a leaf spring structure in which a band-shaped thin metal plate is bent in a saw blade shape, it can be extended and contracted in the longitudinal direction and has high flexibility, but is rigid in the width direction, so it is movable. The member and the fixed member are displaceable in the direction of expansion and contraction of the elastic displacement element, while being rigidly connected in the width direction of the elastic displacement element. Therefore, the movable member and the fixed member can be stably connected with one degree of freedom so as to be elastically displaceable.
Therefore, the movable member and the fixed member are connected with a simple elastic joint with one degree of freedom of compliance.
[0019]
Embodiment 4 (corresponding to claim 7)
The fourth embodiment is characterized in that a locking means for selectively locking the movable member and the fixed member in the first to fourth embodiments is provided.
[0020]
[Action]
Since the movable member and the fixed member can be appropriately locked, by locking both members, the compliance device can be protected from extreme vibration and the like.
[0021]
Embodiment 5 (corresponding to claim 8)
In the fifth embodiment, the two compliance devices are combined and connected so that the displacement direction of the elastic displacement element of one compliance device and the displacement direction of the elastic displacement element of the other compliance device are perpendicular to each other. That is.
[0022]
Embodiment 6 (corresponding to claim 9)
The sixth embodiment has a hand external force calculating means for calculating an external force acting on the hand from a combination of the forces of the respective elastic displacement elements.
[0023]
Embodiment 7 (corresponding to claim 10)
Embodiment 7 has a hand displacement amount calculating means for calculating a relative displacement amount between the hand and the robot arm based on a combination of the displacement amounts of the respective elastic displacement elements.
[0024]
Embodiment
Next, examples will be described with reference to the drawings.
Embodiment 1
Embodiment 1 shown in FIG. 1 is a two-degree-of-freedom compliance device formed by combining two sets of one-degree-of-freedom elastic displacement elements.
The movable member 11 is connected to the intermediate member 12 via first elastic displacement elements 13a and 13b having the same elastic coefficient. The intermediate member 12 is connected to the fixed member 15 via second elastic displacement elements 16a and 16b having the same elastic coefficient. The first elastic displacement elements 13a and 13b and the second elastic displacement elements 16a and 16b are arranged so that the displacement directions are perpendicular to each other. The hand is fixed to the movable member 11, and the fixed member 15 is fixed to the tip of the robot arm. As shown in FIG. 4, the elastic displacement elements 13a, 13b, 16a, and 16b are saw blade-shaped leaf springs, and have high elasticity in the longitudinal and vertical directions, but in the lateral direction. Has high rigidity.
Therefore, the movable member 11 and the intermediate member 12 can be relatively displaced in the left-right direction in FIG. 1, but cannot be relatively displaced in the front-rear direction. On the other hand, the intermediate member 12 and the fixed member 15 can be relatively displaced in the front-rear direction in FIG. 1, but cannot be relatively displaced in the left-right direction. Therefore, the movable member 11 and the fixed member 15 are connected in a stable relationship, and can be relatively displaced forward, backward, left, and right.
[0025]
Further, the ends of the elastic displacement element are fixed in a state of being fitted into the concave portions of the movable member, the intermediate member, and the fixed member, respectively. The first piezoelectric materials 14a, 14b, Piezoelectric materials 17a and 17b are fitted respectively to receive the force applied to the elastic displacement element.
When an external force is applied to the hand, the first elastic displacement elements 13a and 13b and the second elastic displacement elements 16a and 16b elastically expand and contract in the direction of the arrow according to the magnitude and direction of the external force, and the movable member 11 is moved. It moves relative to the fixed member 15. At this time, the first piezoelectric materials 14a, 14b provided between the intermediate member 12 and the first elastic displacement elements 13a, 13b are subjected to the first elastic displacement by the expansion and contraction of the first elastic displacement elements 13a, 13b. The same force as that acting on the elements 13a and 13b is applied to generate a slight distortion. The first piezoelectric materials 14a and 14b generate potentials proportional to the respective strains due to the piezoelectric effect. This potential is measured by a potential measuring means (not shown), and a force acting on the first piezoelectric materials 14a, 14b is calculated by a force calculating means (not shown), so that the first elastic displacement elements 13a, 13b are calculated. Find the acting force. Similarly, a force acting on the second elastic displacement elements 16a, 16b is obtained by calculating a force acting on the second piezoelectric materials 17a, 17b. The deformation directions of the first elastic displacement elements 13a and 13b and the second elastic displacement elements 16a and 16b are shifted by 90 degrees, and act on the first elastic displacement elements 13a and 13b by hand external force calculating means (not shown). The sum of the sum of the force vectors and the sum of the force vectors acting on the second elastic displacement elements 16a and 16b is calculated, and the force vector acting on the hand is obtained. Further, the hand displacement amount calculating means (not shown) calculates the sum of the displacement vector of the first elastic displacement element 13a, 13b and the displacement vector of the second elastic displacement element 16a, 16b, and calculates the relative displacement between the arm and the hand. Ask for.
[0026]
The movable member 11 of the first embodiment is a square plate having a thickness of 6 mm and a size of 60 mm × 60 mm, and the fixed member 15 is a square plate having a thickness of 7 mm and a size of 108 mm × 108 mm. The member 12 is a square plate having a thickness of 6 mm and a hollow 92 mm × 92 mm. These three plates are combined as shown by front and rear, left and right elastic displacement elements 13a, 13b, 16a and 16b. Between the movable member and the intermediate member, there are play gaps for compliance on both the left and right sides, and minute gaps that can slide relatively on both the front and rear sides are interposed. Similarly, between the intermediate member 12 and the fixing member 15, there are play gaps for compliance on both front and rear sides, and minute gaps on the left and right sides are provided to allow relative sliding.
[0027]
Embodiment 2
Next, a second embodiment will be described with reference to FIGS. This embodiment is different from the first embodiment in the means for measuring the force applied to the elastic displacement element, and is not particularly different from the first embodiment.
FIG. 2 shows a compliance device having one degree of freedom, and particularly assumes an operation in which compliance performance is required only in one direction.
In FIG. 2, the movable member 1 is connected to the fixed member 2 via elastic displacement elements 3a and 3b having the same elastic coefficient. A hand (not shown) is fixed to the movable member 1. The fixing member 2 is fixed to a tip of a robot arm (not shown). When an external force is applied to the hand, the elastic displacement elements 3a and 3b elastically expand and contract in the arrow direction according to the magnitude and direction of the external force, and the movable member 1 moves relative to the fixed member 2. At this time, the variable resistor movable section 5 fixed to the moving member 1 linearly moves with respect to the variable resistor (for example, potentiometer) main body 4 fixed to the fixed member 2. The resistance value of the variable resistor main body 4 is measured by measuring means (not shown), and the displacement amount of the elastic displacement elements 3a, 3b is calculated by displacement amount calculating means (not shown). The force acting on the elastic displacement elements 3a, 3b is calculated by force calculating means (not shown) from the measured displacement amounts of the elastic displacement elements 3a, 3b and the elastic coefficients of the elastic displacement elements 3a, 3b which are known values.
[0028]
The second embodiment is a one-degree-of-freedom compliance device, and the displacement of the elastic displacement elements 3a and 3b is the relative displacement of the arm and the hand. The sum of the forces acting on the elastic displacement elements 3a and 3b is the external force acting on the hand.
[0029]
The second embodiment is an example in which the force measuring means of the elastic displacement element in the one-degree-of-freedom compliance device is constituted by the variable resistor main body 4 and the variable resistor movable section 5, but as shown in FIG. It is also possible to apply the force measuring means using the variable resistor main body 4 and the variable resistor movable section 5 to the compliance device having two degrees of freedom without any problem.
[0030]
Next, details of the elastic displacement elements (saw blade-shaped leaf springs) in the first and second embodiments will be described with reference to FIG.
The elastic displacement element is a corrugated leaf spring having a width of 6 mm, a free length of 10 mm and a plate thickness of 0.7 mm, a spring coefficient of 0.5 kg / mm, and a preload of 0 kg (free state, FIG. 4B). It is assembled in. FIG. 4B shows a state in which no force is applied to the elastic displacement element 23 (however, the sign of the leaf spring in FIG. 4), that is, a free state. In this state, the movable member 21 and the fixed member 22 are in a neutral state. There is no relative displacement between them. For example, when compliance (natural positioning) is performed in the part assembling operation, the movable member is relatively displaced with respect to the fixed member, whereby one of the pair of elastic displacement elements 23 facing each other as shown in FIG. Then, it is compressed in the longitudinal direction (X direction), and the other is expanded by the same length in the same direction as shown in FIG. Since the elastic displacement element 23 is made of a steel plate having a width of 6 mm and a thickness of 0.7 mm, the elastic displacement element 23 has elasticity in a direction (Y direction) perpendicular to the direction of expansion and contraction on the paper surface, but has a width direction (Z direction). High rigidity. And since the elastic displacement element 23 is arranged with its width direction up and down, the movable member is elastically connected to the fixed member through the elastic displacement element 23 in the front-back and left-right directions. In the vertical direction, it is almost rigidly connected.
[0031]
Next, the locking means of the compliance device will be described with reference to FIGS.
An air cylinder 44 is embedded in one side of the fixed member 42 such that the stroke direction is perpendicular to the movable direction of the movable member 41. A tapered pin 45 is fixed to the tip of the air cylinder 44, and the pin 45 is fitted into a hole 46 provided in the movable member 41 by the pushing operation of the air cylinder 44, and the movable member 41 is fixed to the fixed member 42. And the compliance device is held inactive. When the pushing operation of the air cylinder 44 is released, the pin 45 is completely removed from the hole, the lock on the movable member 41 is released, and the compliance device returns to the operating state.
[0032]
Although the example of FIG. 5 is an example of the locking means between the movable member 41 and the fixed member 42 in the one-degree-of-freedom compliance device, as shown in FIG. 6, the movable member in the two-degree-of-freedom compliance device of FIG. It is possible to apply the same locking means between the intermediate member 11 and the intermediate member 12 and between the intermediate member 12 and the fixed member 15 without any problem.
[0033]
Next, an outline of the operation in the operation of fitting the fitting component 64 to the fitting component 65 by the robot arm to which the compliance device of the present invention is applied will be described with reference to FIG.
In FIG. 8, a compliance device 62 is interposed between the tip of the robot arm and the hand 63. The fitting part 64 is gripped by the hand 63, the posture and the position of the fitting part 64 are adjusted with respect to the fitting part 65 placed on the table, and the fitting part 64 is brought closer to the fitting part 65 in this state. The position is compensated for by the compliance device 62, and the position is fitted to the fitted part 65. At this time, when compensating for the above-mentioned posture and position deviation, the force or displacement of the elastic displacement element is detected by the compliance device 62, and the calculated force or displacement of the elastic displacement element is applied to the hand 63 by the calculation device 66. The acting force is calculated and detected. The detected value of this force is fed back to the robot controller 67, the direction of the external force and moment applied to the hand 63 is determined based on the detected value, and the translation force and moment other than the component insertion direction of the hand 63 are reduced. The robot arm is controlled in the direction, the posture and the position of the fitting component 64 with respect to the fitting component are adjusted, and the fitting component 64 is fitted to the fitting component without difficulty.
[0034]
【The invention's effect】
The present invention is as described above. The effects of the present invention are summarized as follows for each of the claimed inventions.
(1) Claim 1
The movable member fixed to the hand and the fixed member fixed to the robot arm are connected by an elastic displacement element having an elastic displacement of one degree of freedom, and between the elastic displacement element and the movable member, or between the elastic displacement element and the fixed member. The provision of the force measuring means for measuring the reaction force received from the elastic displacement element in between allows the compliance element and the sensing element to be integrated. Accordingly, a small and lightweight compliance device having a force sensing function and capable of performing high-precision work can be provided.
[0035]
(2) Claim 2
The piezoelectric material embedded between the elastic displacement element and the movable member, or between the elastic displacement element and the fixed member, the potential measuring means for measuring the potential of the piezoelectric material, and the output of the potential measuring means act on the piezoelectric material. By calculating the applied force, the magnitude of the force applied to the elastic displacement element can be accurately measured regardless of the magnitude of the deformation of the elastic displacement element. Accordingly, a small and lightweight compliance device having a force sensing function and capable of performing high-precision work can be provided.
[0036]
(3) Claim 3
By calculating the amount of displacement of the elastic displacement element from the output value of the force measuring means according to the first aspect of the present invention, it is possible to provide a compliance device capable of performing highly accurate work.
[0037]
(4) Claim 4
A movable member fixed to the hand and a fixed member fixed to the robot arm are connected to each other via an elastic displacement element which elastically displaces in one degree of freedom, and a displacement amount measuring means for measuring a displacement amount of the elastic displacement element is provided. Thus, the compliance element and the sensing element can be integrated. This makes it possible to provide a small and lightweight compliance device capable of performing highly accurate work.
[0038]
(5) Claim 5
By providing the force calculating means for calculating the magnitude of the force acting on the elastic displacement element from the output value of the displacement measuring means, it is possible to provide a compliance device having a force sensing function and capable of performing highly accurate work.
[0039]
(6) Claim 6
Since the elastic displacement element has a leaf spring structure in which a thin band-shaped metal plate is bent like a saw blade, accurate elastic deformation with one degree of freedom is possible. This makes it possible to provide a compliance device capable of performing highly accurate work.
[0040]
(7) Claim 7
Since the compliance device has the locking means, it is possible to prevent the hand tip from vibrating due to the operation before the transfer or the operation. Therefore, damage to the compliance device due to the vibration can be avoided.
[0041]
(8) Claim 8
A combination of the two compliance devices, wherein the compliance devices are connected such that the displacement directions of the elastic displacement elements of the respective compliance devices are perpendicular to each other, so that compliance and sensing of the individual elastic displacement elements are achieved. Are independent of each other, so that there is no mechanism interference, accurate compliance can be obtained, and force calculation can be easily performed.
[0042]
(9) Claim 9
Since there is a hand external force calculating means for calculating an external force acting on the hand from a combination of the forces of the respective elastic displacement elements, it is possible to control the robot arm which feeds back the force acting on the hand.
[0043]
(10) Claim 10
By providing the hand displacement amount calculating means for calculating the relative displacement amount between the hand and the robot arm from the combination of the displacement amounts of the elastic displacement elements, it is possible to control the robot arm by feeding back the position of the hand.
[Brief description of the drawings]
FIG. 1 is a horizontal sectional view of a first embodiment.
FIG. 2A is a plan view of a second embodiment, and FIG. 2B is a front view.
FIG. 3A is a plan view of another example of the second embodiment, and FIG. 3B is a cross-sectional view.
FIG. 4 is an enlarged view of an elastic displacement element according to the first and second embodiments.
FIG. 5 is a plan view illustrating a lock unit according to a second embodiment.
FIG. 6 is a plan view showing a lock unit according to the first embodiment.
7A is a conceptual diagram of a main part of a robot arm having a compliance device, and FIG. 7B is a conceptual diagram in a case where force measuring means is simply added to the robot arm of FIG.
FIG. 8 is a conceptual diagram of the robot arm control system of the embodiment.
FIG. 9A is a side view of a main part of a conventional compliance device having a force measuring unit, and FIG. 9B is a plan view.
[Explanation of symbols]
1, 11, 21, 41: movable member
2, 15, 22, 42: fixing member
3a, 3b, 23: elastic displacement element
4: Variable resistor body
5: Variable resistor moving part
13a, 13b: first elastic displacement element
12: Intermediate member
14a, 14b: first piezoelectric material
16a, 16b: second elastic displacement element
17a, 17b: second piezoelectric material
44: Air cylinder
45: Pin
46: Hole
51: Hand side plate
52: Arm side plate
53: Elastic member
54: Robot arm
55: Hand
56: Fitting parts
57: Part to be mated
58: Force sensor
61: Robot
62: Compliance
63: Hand
64: Fitting parts
65: Part to be mated
66: Computing device
67: Robot controller

Claims (11)

A joint mechanism for connecting the hand and the robot arm,
By an elastic displacement element that performs elastic displacement of one degree of freedom by an external force, the movable member fixed to the hand and the fixed member fixed to the robot arm are directly or indirectly connected,
A compliance device comprising a force measuring means for measuring a reaction force received from the elastic displacement element between the elastic displacement element and the movable member or between the elastic displacement element and the fixed member. The force measuring means is a piezoelectric material sandwiched between the elastic displacement element and the movable member or the fixed member, and has a potential measuring means for measuring a potential of the piezoelectric material, and an output of the potential measuring means. 2. The compliance device according to claim 1, further comprising a force calculating means for calculating a force acting on the piezoelectric material from the following. 2. The compliance device according to claim 1, further comprising a displacement amount calculating unit that calculates a displacement amount of the elastic displacement element from an output value of the force measuring unit. A joint mechanism for connecting the hand and the robot arm,
The movable member fixed to the hand and the fixed member fixed to the robot arm are connected by an elastic displacement element that performs one degree of elastic displacement by an external force,
A compliance device comprising a displacement measuring means for measuring a displacement of the elastic displacement element. 5. The compliance device according to claim 4, further comprising a force calculation unit that calculates a magnitude of a force acting on the elastic displacement element from an output value of the displacement amount measurement unit. 6. The compliance device according to claim 1, wherein the elastic displacement element has a leaf spring structure obtained by bending a strip-shaped thin metal plate into a saw blade shape. 7. The compliance device according to claim 1, further comprising a lock unit for selectively locking the movable member and the fixed member. The two compliance devices are combined and connected so that the displacement direction of the elastic displacement element of one compliance device and the displacement direction of the elastic displacement element of the other compliance device are perpendicular to each other. Compliance equipment. 9. The compliance device according to claim 8, further comprising a hand external force calculating means for calculating an external force acting on the hand from a combination of the forces of the elastic displacement elements. 9. The compliance device according to claim 8, further comprising a hand displacement amount calculating unit that calculates a relative displacement amount between the hand and the robot arm based on a combination of the displacement amounts of the elastic displacement elements. A robot arm comprising the compliance device according to claim 1.

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