JP2002166383A - Tactile system for robot arm mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tactile system for a robot arm mechanism capable of easily detecting generation of slipping of an object in a grasping mechanism. SOLUTION: Two grasping parts 21 and 22 are rotatably disposed respectively on both sides of a main body of the grasping mechanism 20 installed on a tip part of a multifunctional arm 10 of a working robot. An auxiliary grasping part 24 is disposed on an opposite side. An expansion body 28 is disposed on the four grasping arms 21 and 22, respectively. When grasping the object 90, the expansion body 28 is expanded so that cushion effect is exhibited on a contact part between the arms and the object. Pressure sensors 60a and 60b, vibration sensors 61a and 61b, acoustic sensors 62a and 62b, and acceleration sensors 63a and 63b are provided on the grasping mechanism 20. Signals from these sensors are taken into a control device 65, and a state that the object 20 slips is detected from the change of the respective signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tactile system for a robot arm mechanism applied to work in outer space on a satellite or a space station, or work in a special plant such as a nuclear power plant, etc. This is a system that detects slippage of an object when the object is moved and securely grips the object.

[0002]

2. Description of the Related Art The applicant of the present invention has proposed various types of working robots for the purpose of checking the module body of a space station inside and outside a ship and replacing equipment. One example of the working robot will be described with reference to FIG. In the figure, reference numeral 1 denotes a main body, and four connecting portion arms 10, 11, and 1 are provided at four corners on a lower surface.
2 and 13 are provided. The multifunctional arm 10 is connected by connecting portions 10a, 10b, and 10c and can freely rotate in a three-dimensional direction. Similarly, the multifunctional arm 11 is the connecting portions 11a, 11b, and 11c, and the multifunctional arm 12 is The connecting parts 12a, 12b, and 12c and the multifunctional arm 13 are also connected by connecting parts 13a, 13b, and 13c, respectively, so that the four arms 10, 11, 12, and 13 can be freely moved by changing them freely. Configuration.

An operating tool 2 is connected to connecting portions 10c, 11c, 12c, and 13c of the arms 10, 11, 12, and 13, respectively. A camera 3 and a light 4 are attached to the side of the operation tool 2, and the light 4 is turned on by a control device (not shown), the image of the camera 3 is captured, data processing is performed, and status monitoring and position confirmation are performed. The operating tool 2 is provided with an adapter for gripping bolt heads at the four corners to which the structure is attached, or a screw adapter for removing the bolt and fixing the arm is mounted. The robot having such a structure includes a control device, that is, a control CPU 14, which controls the driving of the motors of the connecting portions of the multifunctional arms 10 to 13 and the operation of the operating tool 2 at the tip of the arm. The multifunction arms 10 to 13 are sequentially moved and actuated by gripping the main body 1 along the structure with the operating tool 2 and holding a projection of the structure, for example, a bolt head. In such a robot, the movement of each arm is controlled by a single control CPU 14 in the main body 1. The robot is equipped with a motor that moves in a three-dimensional direction at each of the connecting portions, and a number of motors and actuators that drive each operating tool.

In the working robot described above,
In the outer space, the operating tool 2 must hold bolts of various shapes and sizes, large and small work sockets, handrails, and the like. For that purpose, it is necessary to replace the operating tool with the one that matches the shape and size of the gripping part according to the purpose and location of the work, and the operating tool must be prepared in various shapes and sizes. . In particular, when gripping a precise object, it is necessary to prevent the hand from colliding or strongly gripping the object to damage or damage the object, and the hand operation also requires fine control. Become.

Therefore, the applicant of the present invention proposes a gripping mechanism that can be mounted on the operating tool 2 at the end of the robot arm or directly mounted on the end of the arm, and can be safely gripped without damaging the object to be gripped. He has also filed a patent application. Next, the main part of this content will be described.

FIG. 4 shows a robot gripping mechanism according to the prior art which is a premise of the present invention, wherein (a) is a front view and (b) is a front view.
FIG. 10 is a side view of the work robot, which is used in place of the operation tool 2 at the tip of the multifunctional arms 10, 11, 12, and 13 of the work robot described in FIG.

In FIG. 4, the gripping mechanism 20 is connected to the multifunctional arm 10 via a rotatable connection. On the opposite sides of the body, grooves 2 extending vertically
5 are provided in parallel, and in these grooves 25, a grip 21 connecting the grips (hand or finger) 21a and 21b, and a grip 22 connecting the grips 22a and 22b are provided. Are slidably engaged. Grip part 21,
Reference numerals 22 denote opposing surfaces, each of which has
The connecting portions 26 at the upper ends of the first and second members are connected to the inside of the groove 25 and can move up and down, and are configured to slide in the up and down direction by a drive mechanism inside the main body (not shown).

The grip 21 is connected to the connecting portion 26 by the grip 21.
a is a gripping portion 21b at the tip of the gripping portion 21a;
, And can be rotated by connecting portions 26 and 27, respectively, and can be bent (the gripping portion 22 is also the same). The vertical movement and bending of the grippers 21 and 22 are controlled by a robot control device (not shown) by controlling the mechanism for moving the ends in the vertical direction and the axes of the connecting parts 26 and 27 to rotate them. Let it.

A groove 25 is provided on another pair of surfaces orthogonal to the surface on which the grip 21 is mounted.
, A pair of auxiliary gripping portions 24 are engaged so as to be vertically movable. The auxiliary gripping portion 24 is connected to the groove 25 at the upper portion, can move up and down, and can turn the tip inward around the end portion.
It is controlled by the control device in the same manner as in 1 and 22.

A piston member 40 which can move up and down is incorporated in the center of the main body. The internal piston member 40 is not shown, but is protruded to form a socket or the like on the outer surface of the module of the space station. The tip is inserted into the hole, the latch mechanism at the tip is taken out, the tip is fixed to the socket, and the multifunctional arm 10 of the working robot is fixed without moving the gripping mechanism.

Reference numeral 28 denotes an inflatable body, which is formed of a sealed bag which expands and expands with gas or air.
22 is attached to the surface facing the main body. When the inflatable body 28 grips a gripping target object with each gripping portion, the inside is filled with glass or air and expanded as described later,
This prevents slippage between a gripping part such as a handrail and a gripping object that comes into contact with the object, and protects the gripping part or the object.

FIGS. 5A and 5B are views showing the operation of the gripping portion of the robot gripping mechanism described above. FIG. 5A shows a state in which the gripping portions 21 and 22 are lowered along the groove, and FIG. In addition to the above, a state where the auxiliary gripping portion 24 is further lowered along the groove 25 is shown. As described above, when gripping an object, both the grippers 21 and 22 and the auxiliary gripper 24 are lowered as necessary, and the arm is bent to grip the object.

FIG. 6 is a diagram showing the entire structure of the robot gripping mechanism.
A recess 29 is formed along the longitudinal direction of the inflatable body 2 in the same manner.
8 are mounted so that the other side projects to the surface when expanded. Numeral 70 denotes a control device for controlling gas or air to flow into and out of the expansion body 28. 42 is a pressurizing device, which pressurizes gas and supplies it to the pipe 50 via the switching valve 41; 43 is a suction device, which is a pipe 51 and the pipe 5 via the switching valve 41;
A gas is sucked from zero. Reference numeral 44 denotes a gas tank, which is a storage tank for storing an inert gas, air, or the like. These 7
Reference numerals 0, 41 to 44 are provided in the robot body 1,
0 passes through the inside of the multifunctional arm 10 and
2 expansion body 28. In addition, this piping 50
Since the multi-function arm 10 is a moving body, it is constituted by a flexible tube such as a flexible tube.

In the above configuration, when the object is gripped by the grippers 21 and 22, the control device 70 switches the switching valve 4.
1 is switched so that the pipe 50 and the pressurizing device 42 are connected, and at the same time, the pressurizing device 42 is operated for a predetermined time. As a result, gas or air is sent from the gas tank 44 to the expansion body 28 through the switching valve 41 and the pipe 50 as shown by the solid arrow in the figure, and expands the expansion body 28. The inflatable body 28 functions as a cushion between the object to be grasped and the contact portion of the grasping portion by inflating, and prevents the two from coming into contact with each other and causing a scratch or the like.

When the grippers 21 and 22 are separated from the object, the control device 70 controls the switching valve 41 so that the pipe 50 and the suction device 43 are connected.
Is operated to cause gas or air to be sucked into the gas tank 44 through the pipe 50, the switching valve 41, and the pipe 51 as shown by the dotted arrow in the figure. Thereby, the gas in the inflatable body 28 is sucked, and the inflatable body 28 is reduced and stored in the concave portion 29. Even when the expansion function of the present expansion body is lost, the gripping function is maintained.

FIGS. 7A and 7B are front views showing various gripping states by the robot gripping mechanism described above. FIG. 7A shows a case where a rectangular hexahedral object 90 is gripped. Are all lowered and the arm 90
This is an example in which both the inflatable bodies 28 of each of the grippers 21 and 22 are inflated, and both side surfaces of the object 90 are gripped via the inflatable bodies 28.

FIG. 7 (b) shows an example in which the object 90 is gripped in the same manner.
The grip portion below the grip portion 21 is bent inward to form the grip portion 2
1 shows an example in which the upper and lower inflatable bodies 28 are inflated, and the gripper 22 inflates only the lower inflatable body 28 and grips the object 90, respectively.

FIG. 7C shows an example in which the rail 92 is gripped. The grips 21 and 22 are all lowered, the lower grip is bent inward to surround the rail, and the inflatable body 28 is This is an example in which the rail 92 is gripped by being inflated.

FIG. 8 shows a case where the end of the handrail is gripped by the gripping mechanism described above.
(B) is an AA arrow view in (a). In (a), first, the grippers 21 and 22 are lowered. next,
Holding part, hand or finger part 21, 22 centering on connecting part 27
Are rotated, and the left and right sides of the handrail end 91 are gripped by the arm end. At the same time, the gripper 2
The inflatable body 28 at the grip portion at the lower end of each of the first and second inflators is inflated and inflated so that the inflatable body 28 has a cushioning effect on the contact between the end of the arm and the end of the handrail. This avoids excessive contact and pressing force at the arm tip and handrail end,
Damage and sliding can be prevented.

Next, the auxiliary gripping portion 24 is also lowered and its tip is similarly rotated to make contact with the front-rear end surface of the handrail end portion 91. In the front-rear direction, only one end surface is provided. However, since the rails are attached to the inner surface and cannot be gripped, the auxiliary gripper 24 can be lowered only on one side, and the other can be held in the upper position. The lower auxiliary gripping portion 24 is rotated by rotating its distal end so as to contact and hold the surface of the handrail end portion 91, so that the handrail is securely gripped.

[0021]

The above-mentioned prior art robot gripping mechanism according to the prior art, when gripping an object, inflates and grips an inflatable body. Also, the object can be prevented from being scratched or damaged, and the object can be reliably grasped. But,
When grasping irregular-shaped objects, objects that are difficult to grasp, or objects that are long and have an imbalanced weight on both sides, etc., the grasping by the grasping unit is insufficient or the position is inappropriate. In some cases, slippage occurs between the inflatable body and the object, resulting in incomplete gripping, which prevents accurate conveyance and operation of the object.

Therefore, the present invention recognizes an insufficient grip by detecting a slip between the object and the inflatable body of the grip portion by a change in pressure, generation of vibration, generation of sound, change in gravity, and the like. An object of the present invention is to provide a tactile system of a robot arm mechanism that can perform accurate gripping of an object by the robot gripping mechanism.

[0023]

The present invention provides the following means (1) to (4) to solve the above-mentioned problems.

(1) The robot has a plurality of arms openably and closably attached to the tip of an arm of the working robot, and an inflatable body mounted inside the arm. In a robot arm mechanism that sandwiches the object with an arm and inflates the inflatable body to grip the object through the inflatable body, the robot arm mechanism includes a pressure sensor that detects a pressure in the inflatable body; A control device that captures a detection signal of the pressure sensor and detects a slip of the object from a pressure change in the inflatable body when the object moves by sliding between the inflatable body and the object. Tactile system for robot arm mechanism.

(2) The robot arm according to (1), wherein the control device can control a gripping force by adjusting a pressure in the inflatable body based on a result of the pressure detected by the pressure sensor. Mechanism tactile system.

(3) In addition to the pressure sensor, a vibration sensor, an acoustic sensor, and an acceleration sensor are further provided, and the control device controls the pressure signal from the pressure sensor, the vibration signal from the vibration sensor, and the The tactile system for a robot arm mechanism according to (1), wherein signals of a sliding sound of the object and a change in acceleration from the acceleration sensor are taken in, and the slip of the object is detected from these signals.

(4) The control device is capable of controlling the gripping force by adjusting the pressure in the inflatable body based on the results detected by the pressure, vibration, sound and acceleration sensors. (3) A tactile system for the described robot arm mechanism.

In (1) of the present invention, a pressure sensor is provided in the robot arm mechanism, and the pressure sensor detects the pressure inside the inflatable body inside the arm and outputs the detection signal to the control device. When the robot arm mechanism grips an object, the object is gripped via the inflatable body of multiple arms.However, in the case of an amorphous object or an object with an unbalanced weight on the left and right, In some cases, slippage occurs with the inflatable body and complete gripping is not possible. When the object slips, the pressure inside the inflatable body fluctuates impulsively compared to the pressure in the steady gripping state, so the controller detects this pressure fluctuation and detects the slip of the object between the inflatable bodies. it can.

When the slip is detected, the gripping of the object is incomplete, and the control device returns the object to the original position under the control of the robot arm mechanism, repeats the gripping again, and attempts to complete the gripping. Therefore, the reliability of the operation of the robot arm mechanism is improved.

In (2) of the present invention, the control device adjusts the pressure of the inflatable body based on the result detected by the sensor, so that the gripping is ensured. In (4) of the present invention, the control device detects the pressure by various sensors. Since the pressure of the inflatable body is controlled based on the result of the signal, a secure grip is achieved.

According to (3) of the present invention, in addition to the pressure sensor, a vibration sensor, an acoustic sensor, and an acceleration sensor are further added to the detection of the slip of the object. Since the signals of the generation of vibration, the generation of slip noise, and the change of acceleration can be input and the slip of the object can be detected comprehensively, the slip of the object can be accurately determined, and the reliability of the system of the invention of the above (1). Is further improved.

[0032]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a configuration diagram of a tactile system of a robot arm mechanism according to an embodiment of the present invention. In the figure, the gripping mechanism 20 has the same structure as that described in the prior art, and inflatable body pressure sensors 60a and 60b are attached to the gripping portions 21 and 22 to detect the pressure in the inflatable body 28. 61a, 61
Reference numeral b denotes a vibration sensor, and when the object 90 is grasped,
0 detects the vibration that occurs when sliding between the gripper and the inflatable body 28. Reference numerals 62a and 62b denote acoustic sensors which detect a sound generated when the object 90 slips. 63a and 63b are acceleration sensors that detect acceleration applied to the gripping mechanism 20 when the object 90 slides.

The above-mentioned pressure sensors 60a, 60b in the expanded body.
Are attached to the side surfaces of the arms of the grippers 21 and 22, and detect the pressing force when the inflating body 28 expands, and also detect the pressure fluctuation when the object 90 slides. Vibration sensors 61a, 61
b and the acceleration sensors 63a and 63b are attached to the main body side of the gripping mechanism 20, and detect vibration and acceleration transmitted to the main body side. In addition, the acoustic sensors 62a and 62b are mounted near the inflatable body 28 so as to easily detect a slipping sound when the object 90 slides between the inflatable body 28, and in this example, the sound sensor 62a and 62b Installed nearby. Basically, these sensors may be attached to any position as long as they are inside the gripping mechanism 20.

The signals of the pressure, vibration, sound, and acceleration detected by each sensor are input to the amplifying unit 64, taken into the control unit 65, and are compared with predetermined values as described later. Is reflected in the control of the multifunctional arm, and is provided for the optimal control of the object 90 by the gripping mechanism 20. The signal of each sensor amplified by the amplification unit 64 may be input to the control device 65 as an analog signal and compared in the state of an analog signal, or may be converted into a digital signal and compared by digital processing. Any method may be used, but when the control of the robot is controlled by a computer, a method of digital processing is preferable in order to link with the control computer.

FIG. 2 is a flowchart of the control performed in the control device 65 shown in FIG. In the figure, the operation of the gripping mechanism of the robot is started in step S1,
2, the sensors 60a, 60b, 61a, 61
b, 62a, 62b, 63a and 63b, the control unit 65 compares the signals from the sensors with reference values in S3. If the signals exceed the reference values in S4, At 90, it is determined that a slip has occurred with the expansion body 28.

That is, in S3, the case of the inflatable body pressure sensors 60a and 60b indicates that the detected pressure in the inflatable body 28 fluctuates more rapidly than the pressure in the normal state of gripping the object. If it exceeds the predetermined range, it is determined that a slip has occurred. Are the vibration sensors 61a and 61b
When the object 90 slides, the pressure of the inflatable body 28 fluctuates, and the arm part is vibrated accordingly.
When this abnormal vibration is detected, it is determined that slippage has occurred.

The sound sensors 62a and 62b detect sound generated when the object 90 slides and rubs against the expansion body 28. When an instantaneous abnormal sound is detected, slippage occurs. It is determined that an error has occurred. Is the acceleration sensor 63
In the cases a and 63b, when the object 90 slips, the arm receives the reaction force, and the acceleration generated at that time is transmitted to the main body. When this instantaneous acceleration occurs, it is determined that the slip has occurred.

Next, if it is determined in S4 that slippage has occurred, the object 90 is returned to the original position in S7, gripping is performed again, the process returns to S2, and the same determination is performed again.
In S4, if slipping does not occur and normal gripping is performed, the gripping operation of the robot is continued in S5, and if there is a next operation in S6, the process returns to S2 again, and the signal from each sensor is taken in and slipping is performed. It is determined whether or not there is, and if there is no next operation in S6, the process ends in S8.

FIG. 3 is a diagram showing the waveform of a detection signal from each sensor when a slip occurs. The vertical axis indicates the magnitude of each signal, the horizontal axis indicates the time axis, and FIG. (B) shows the change in sound pressure due to the generation of vibration, (c) shows the change in sound pressure due to the generation of the sound, and (d) shows the change in acceleration. As shown in the figure, when the object 90 slides between the inflatable body 28 at the time t, the pressure, the amplitude of vibration, the sound pressure, and the acceleration change more rapidly than the normal state of gripping the object 90. The change can determine that the object 90 has slipped.

In the above-described embodiment, all signals of the pressure sensors 60a, 60b, the vibration sensors 61a, 61b, the acoustic sensors 62a, 62b, and the acceleration sensors 63a, 63b are taken into the control device 65 and the object 90 slides. Has been described, the slip of the object 90 is caused by the expansion body 28.
Since it is possible to detect the change of the internal pressure alone with considerable accuracy, the system may be constructed with only the pressure sensors 90a and 90b. However, the configuration including all the sensors as in the present embodiment is more preferable. Accurate judgment can be made.

In the control device 65, these sensors 6
When it is determined that slippage has occurred based on all of the signals 0, 62, and 63, or any of these signals, the amount of gas sent to the inflatable body 28 is controlled in accordance with the magnitude of the signal to control the inflatable body 2.
The pressure in step 8 can be adjusted to control the gripping force. In such control, the control device 65 sends a signal to the control device 70 of the gas generator shown in FIG. 6 to control the gas pressure of the inflatable body 28, so that more reliable gripping is performed.

[0042]

The tactile sensation system for a robot arm mechanism according to the present invention has (1) a plurality of arms attached to the tip of an arm of a working robot so as to be openable and closable, and an inflatable body attached inside the arm. The arm holds the object with each arm when gripping the object, and in a robot arm mechanism that inflates the inflatable body and grips the object through the inflatable body, wherein the robot arm mechanism Is a pressure sensor that detects the pressure in the inflatable body, and captures the detection signal of the pressure sensor. When the object moves by causing a slip between the inflatable body and the object, the object slides from the pressure change in the inflatable body. And a control device for detecting.

With the above system, when the object slips, the pressure in the inflatable body is compared with the pressure in a steady gripping state.
Since it fluctuates impulsively, the controller can detect this fluctuation in pressure and detect slippage of the object between the inflatable bodies.

When this slip is detected, the gripping of the object is incomplete, and the control device returns the object to the original position under the control of the robot arm mechanism, repeats the gripping again, and attempts to complete the gripping. Therefore, the reliability of the operation of the robot arm mechanism is improved.

In (2) of the present invention, the control device adjusts the pressure of the inflatable body based on the result of the detection by the sensor, so that the gripping is surely performed. Since the pressure of the inflatable body is controlled based on the result of the signal, a secure grip is achieved.

According to (3) of the present invention, in addition to the pressure sensor, a vibration sensor, an acoustic sensor, and an acceleration sensor are further added to the detection of the slip of the object. Since the signals of the generation of vibration, the generation of slip noise, and the change of acceleration can be input and the slip of the object can be detected comprehensively, the slip of the object can be accurately determined, and the reliability of the system of the invention of the above (1). Is further improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a tactile system of a robot arm mechanism according to an embodiment of the present invention.

FIG. 2 is a flowchart of a control device of the system according to the embodiment of the present invention.

FIG. 3 is a waveform diagram of a signal for detecting a sliding state of an object in the tactile system of the robot arm mechanism according to the embodiment of the present invention.

FIG. 4 shows a robot gripping mechanism according to the prior art;
(A) is a front view, (b) is a side view.

FIG. 5 shows a robot gripping mechanism according to the prior art (a).
FIG. 4 is a front view of a state in which a gripping unit, a hand or a finger is lowered, and FIG.

FIG. 6 is an overall configuration diagram of a robot gripping mechanism according to the prior art.

FIGS. 7A and 7B are front views showing gripping states of a robot gripping mechanism according to the prior art, and FIGS. 7A, 7B, and 7C each showing various different gripping states; FIGS.

8A and 8B show a state in which a handrail is gripped by a robot gripping mechanism according to the prior art, wherein FIG. 8A is a front view and FIG. 8B is a side view.

FIG. 9 is a perspective view showing an example of a robot working in outer space.

[Explanation of symbols]

 Reference Signs List 10 multifunctional arm 20 gripping mechanism 21, 22 gripping part 25 groove 26, 27 connecting part 24 auxiliary gripping part 28 inflatable body 60a, 60b inflatable body pressure sensor 61a, 61b vibration sensor 62a, 62b acoustic sensor 63a, 63b acceleration sensor 64 amplification Part 65 Control device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01L 17/00 G01L 17/00 Z F-term (Reference) 2F055 AA11 BB20 CC60 DD20 EE40 FF28 3C007 DS01 ES05 ES07 ET03 EV14 EV23 EV26 KS32 LV10 3F059 AA20 BB06 DC03 DC05 DD01 DD15 DD18 FC04 3F061 AA01 BA05 BA07 BB03 BE24 BE36 BE43 DD02 DD04

Claims (4)

[Claims] 1. A work robot comprising: a plurality of arms attached to a tip end of an arm of a work robot so as to be openable and closable; and an inflatable body attached inside the arm. In the robot arm mechanism that sandwiches the object with the inflatable body and inflates the inflatable body to grip the object through the inflatable body, the robot arm mechanism includes a pressure sensor that detects a pressure in the inflatable body. A control device that receives a detection signal of a pressure sensor and detects a slip of the object from a change in pressure in the inflatable body when the object moves by sliding between the inflatable body and the object. Tactile system of arm mechanism. 2. The robot arm mechanism according to claim 1, wherein the control device can control a gripping force by adjusting a pressure in the inflatable body based on a result of the pressure detected by the pressure sensor. Tactile system. 3. In addition to the pressure sensor, a vibration sensor, an acoustic sensor, and an acceleration sensor are further provided, and the control device includes a pressure signal from the pressure sensor, a vibration signal from the vibration sensor, and a signal from the acoustic sensor. 2. The tactile sensation system for a robot arm mechanism according to claim 1, wherein each signal of a slip noise and a change in acceleration from the acceleration sensor is taken in, and the slip of the object is detected from each of the signals. 4. The gripping force can be controlled by adjusting a pressure in the inflatable body based on a result detected by the pressure, vibration, sound and acceleration sensor. Tactile system of the robot arm mechanism.