JPH0741561B2 - Control method of multi-finger manipulator - Google Patents

Description

The present invention relates to a control method applied to a master-slave multi-finger manipulator.

<Prior Art> A conventional control method for a master-slave multi-finger manipulator focuses on the relationship between the joint angle of each finger between the master finger and the corresponding slave finger. ,
The angle of the master finger joint is reproduced as it is in the corresponding slave finger joint. Therefore, this conventional control method is often applied when using a so-called master having the same structure in which the master finger and the slave finger have the same axis configuration.

FIG. 5 is a diagram showing the above-described conventional control method, which has a plurality of master fingers 2 and slave fingers 3 corresponding to these, and each master finger 2 is attached to the operator 1 and the operator 1 Each joint 21,22,23,24 moves according to the movement of the finger of.

Here, focusing on the pair of fingers 2 and 3 corresponding to the index finger,
The angle α _M1 of the first joint 21 of the master finger 2 and the angle α _M2 of the second joint 22 are detected, and the detected joint angle α _M1 is reproduced as it is as the angle α _S1 of the first joint 31 of the slave finger 3, The detected joint angle α _M2 is also reproduced as it is as the angle α _S2 of the third joint 32 of the slave finger 3. That is, α _S1 = α _M1 and α
Control is performed so that _S2 = α _M2 . The same is true between the other pair of fingers 2 and 3 corresponding to the thumb, and the angles β _M1 and β _M2 of the first and second joints 23 and 24 of the master finger 2 are detected, and these joint angles β _{Let M1} and β _{M2 be} the first and second joints 3 of the slave finger 3, respectively.
Reproduced as angles β _S1 and β _S2 of 3,34.

When the master-slave control of the multi-finger manipulator is performed by the conventional control method shown in FIG. 5, if the master finger 2 and the slave finger 3 forming a pair have the same size and the same structure, they are detected by the master finger 2. By reproducing the joint angle on the slave finger 3, the slave finger 3 moves as desired by the operator 1 who operates the master finger 2. For example, when the operator 1 imagines trying to grab an object of a certain size and creates a finger shape for holding that size on the master finger 2, the slave finger 3 is also imaged by the operator 1. The shape is exactly the same as that described above, and an actual object can be gripped.

However, since the slave finger 3 has various shapes and structures depending on its use, the slave finger 3 usually has a different shape from the master finger 2 worn by the operator 1. Further, the master finger 2 itself does not always have the same structure as a human finger depending on its usability.

Therefore, in the conventional control method in which the joint angle of the master finger described above is reproduced as it is in the joint angle of the corresponding slave finger, in many cases, the operator can handle the object with the same feeling as when operating with his / her own finger. It cannot be done, and it must be said that the operability of the slave finger by the master finger is greatly reduced.

<Improvement of Prior Art> Therefore, when a human normally handles an object with his / her fingers, the present inventors consider not the individual joint angles but the position of the finger tip and the angle between the object to be handled and the finger, that is, the shape made by the finger. Focusing on consciousness, as shown in FIG. 6, between the master finger 2 and the slave finger 3, for each pair of corresponding fingers, the master finger 2
Of the slave finger 3 is individually reproduced as the finger tip vector 43 (44) of the slave finger 3.

Details of this control method will be described with reference to FIG. In FIG. 6, the control system first sets the angle detecting unit 101 to the position 1 of the master finger 2.
Angles α _M1 , α _M2 (β of all joints 21,22 (23,24) for each finger
_M1 , β _M2 ) is detected, and the master finger tip position calculation unit 102
The master finger tip position, that is, the finger tip position of the operator 1 is obtained in a coordinate system with the master finger root as the origin. Then, when each master finger tip position moves, the slave finger tip position calculation unit 103 is moved so that the slave finger tips move in the same direction as the moving direction of the master finger tip by the same amount or by a predetermined number of times.
Then, the master finger tip position is defined as the slave finger tip target position with the root of the slave finger 3 as the origin, and the slave joint angle calculation unit 104 requires the slave finger tip to reach the slave finger tip target position. Each joint of the finger 3 31,32 (33,3
4) Find the angles α _S1 , α _S2 (β _S1 , β _S2 ).

Further, the control system is configured such that the operator finger shape calculation unit 105 uses the master finger 2
The joint shape α _M1 , α _M2 (β _M1 , β _M2 ) and the joint angle link length are used to determine the finger shape of the operator 1, especially the posture of the finger tip, and the slave finger shape calculation unit 106 The shape of the slave finger, especially the posture of the tip of the slave finger, is obtained from the joint angles α _S1 , α _S2 (β _S1 , β _S2 ) of the slave finger 3 and the length of the joint angle link, and the joint angle offset is obtained from the difference between these finger shapes. The calculation unit 107 calculates each joint angle offset of the slave finger 3.

Then, the control system adds the respective joint angle offsets to the angular joint angles α _S1 , α _S2 (β _S1 , β _S2 ) of the slave finger 3, and the slave joint angle command unit 108 adds the added value to the final slave joint angle. Output as command value.

As described above, the finger tip position and the finger shape (finger tip posture) of the operator 1 are almost accurately reproduced as the finger tip position and the finger shape (finger tip posture) of the slave finger 3. Therefore, compared with the control method described in FIG. 5 in which the joint angle of the master finger 2 is reproduced as it is as the joint angle of the slave finger 3, the control method described in FIG. There is an advantage that it can be applied to the case where different, so-called different structure masters are used.

<Problems to be Solved by the Invention> However, in any of the control methods shown in FIGS. 5 and 6, information (joint angle or finger tip position) obtained by one master finger 2 is stored in this master finger 2. It is used only to control the corresponding single slave finger. That is, since the information relationship between the master finger 2 and the slave finger 3 is a one-to-one relationship, there is the following inconvenience.

When the operator 1 images a certain object to grasp a certain object and forms a finger, for example, an image of grasping an object having a diameter A with the fingertips, an object having a diameter A is formed between the fingertips of the two slave fingers 3. It must be open to size A, not narrow or wide for gripping.

However, since the master finger 2 and the slave finger 3 have a one-to-one relationship in both control methods as described above, there is no guarantee that the fingertips of the slave finger 3 will be opened to a size of just A.

Therefore, in order to actually grab an object, the operator 1 is forced to perform a work in which the image is changed, which requires not only skill but also complicated operation, such as rotating the object with a fingertip. Well, when it comes to hunting,
Infeasible.

It is an object of the present invention to provide a control method that allows a master-slave multi-finger manipulator to perform complicated or delicate work without special training by an operator.

<Means for Solving the Problems> A method for controlling a multi-finger manipulator according to the first invention is
In a master-slave multi-finger manipulator, calculate the finger tip vector of each master finger from the joint angle of the master finger, and calculate the finger tip vector between master fingers from the finger tip vector of each master finger. , Calculate the finger tip vector of each slave finger so that the finger tip vector of the slave fingers matches the corresponding finger tip vector of the master fingers. It is characterized in that the joint angle is calculated and the slave finger is driven with the calculated joint angle as a command value.

A multi-finger manipulator control method according to a second aspect of the present invention is a master-slave multi-finger manipulator in which a finger tip vector of each master finger is calculated from a joint angle of the master finger. Calculating a finger tip-to-tip vector between the master fingers based on the tip end position of the specific one master finger from the tip vector; and based on the joint angle of the specific one master finger, the specific one master finger Calculating the joint angle of the specific one slave finger, which is based on the finger tip vector between the master fingers and the joint angle of the specific one slave finger. Slave other than the specific one slave finger is set so that the finger tip-to-tip vector between slave fingers with the finger tip position as a reference point matches the corresponding finger-tip vector between master fingers. Calculating the finger tip vector of the finger, calculating each joint angle of the slave fingers other than the specific one slave finger from the finger tip vector of the slave, and specifying the calculated joint angle as a command value Each slave finger including one slave finger is driven.

<Operation> When an operator sees a certain object and grasps it or manipulates the grasped object, the operator does not pay attention to the tip positions of the individual fingertips but the relative relationship between the fingertips. Is often aware of. For example, considering the case of gripping an object with a diameter A and rotating it, physically, the finger is twisted while constantly maintaining the distance between the finger tips at a distance of A, but in reality, humans The finger tip position itself is not consciously moved, but the finger tips are unconsciously kept at a constant interval A. That is, the relative relationship between the finger tips is controlled.

The present invention is based on the above knowledge, and the most important information when a person grips an object or manipulates the gripped object is that the width of the object is equal to the interval between the finger tips, that is, [object Width] = [gap between finger tips],
It is considered that realizing this relationship with a master-slave multi-finger manipulator will lead to the greatest improvement in operability.

Since the vector between finger tips represents the distance and direction between the finger tips, if the vector between finger tips of slave fingers is made to match the vector between finger tips of corresponding master fingers, the operation with respect to the master finger is performed. Then, in the slave finger, the relationship of [width of object] = [spacing between finger tips] is established,
You can freely grasp or manipulate objects with slave fingers.

Further, as long as the relationship of [width of object] = [distance between finger tips] is maintained, the joint angle between the master and slave fingers must be the same for each corresponding joint as before. It does not necessarily have sex, and there is no problem in operation even if they do not match.

Therefore, in the first invention, first, the finger tip vector of each master finger is calculated from the joint angle of the master finger, and the finger tip-to-tip vector between the master fingers is calculated from these. In contrast,
When the finger tip vectors of the slave fingers are calculated so that the finger tip vectors of the slave fingers match the corresponding finger tip vectors of the master fingers, the finger tip vectors of the slave fingers are also [object width] = The relationship [distance between finger tips] is satisfied. Furthermore, when each joint angle of the slave finger is calculated from the finger tip vector of each slave finger, each joint angle also satisfies the relationship of [width of object] = [interval between finger tips], and these joint angles are By driving the slave finger as the command value, the work as a human image is performed.

In this case, the origin between the finger tip vectors needs to exist, but it is theoretically free to set the origin, and it may be set arbitrarily.

In the second invention, the origin is most easily taken, and the finger tip-to-tip vector between the master fingers is calculated with the finger tip position of a specific one master finger among the plurality of master fingers as a base point. Further, the base point of the finger tip-to-finger vector of the slave fingers is the finger tip position of one specific slave finger corresponding to one specific master finger among the plurality of slave fingers.
Then, the joint angle of the specific one slave finger is calculated based on the joint angle of the specific one master finger as in the conventional case.
Even if the joint angle of one specific slave finger is calculated in this way, it does not affect the relationship between the vector between the finger tips of the master fingers and the vector between the finger tips of the slave fingers.
The finger tip vectors of the other slave fingers are calculated so that the finger tip vectors of the slave fingers match the finger tip vectors of the master fingers, and then the joint angle is calculated.
Since the joint angles of the specific one slave finger calculated in this way and the joint angles of the other slave fingers satisfy the relationship of [width of object] = [spacing between finger tips], these joint angles are commanded. By driving the slave finger as a value, a human street image work is performed.

In both the first and second inventions, it is sufficient that the vector between the finger tips of the slave fingers matches the vector between the finger tips of the master fingers. Therefore, as described above, each slave finger serving as the command value is set. The joint angle of does not necessarily match the joint angle of the corresponding master finger as in the conventional case.
As described above, since the finger tip-to-tip vector of the master finger is reproduced as the finger tip-to-tip vector of the slave finger, when the operator performs a certain operation on the master finger, the positional relationship between at least the finger tips of the slave fingers is Is equivalent to the positional relationship between each finger tip of the master finger, and it is guaranteed that the distance between the finger tips and the direction of the other finger tip viewed from one finger tip are exactly the same for the master finger and the slave finger. To be done. This is true regardless of whether the master finger and the slave finger have the same structure or different structures.

Therefore, according to the control method of the present invention, the ability of a human to unconsciously perform his own experience, that is, the ability to control the relative positional relationship between finger tips, is faithfully reflected on the slave finger, and the operator Allows the slave fingers to perform the work as intended by the master fingers without feeling discomfort.

<Examples> Fig. 1 is an example showing the principle of the control method of the multi-finger manipulator according to the present invention, and the link joint angles α _M1 , α _M2 , β _M1 , and β detected by the two master fingers 2 are shown. The finger tip vectors 41, 42 of each master finger 2 are obtained from _M2 , and the inter-finger tip vector 5 is first calculated from these two finger tip vectors 41, 42. That is, as shown in FIG. 2, if a certain position O at the base of the finger is the origin (0,0,0) of the three-dimensional (X, Y, Z) coordinates, the tip position A (X ₁ , Y ₁ , Z ₁ ) is the joint angle α ₁ ,
The coordinates of the point determined by β ₁ , and the tip position B of the other finger
Similarly, (X ₂ , Y ₂ , Z ₂ ) is the coordinates of a point determined by the joint angles α ₂ and β _{2 of the} finger, ▲ ▼ and ▲ ▼ are finger tip vectors, and ▲ ▼ is between the finger tips. Is a vector. Therefore, the vector between finger tips is Is obtained as.

Next, in the two slave fingers 3, the finger tip vectors 43, 44 of each slave finger 3 are calculated so that the finger tip tip vector 5'matches the previously obtained master finger tip tip belt 5. Next, the joint angles α _S1 , α _S2 , β _S1 , and β _S2 of the slave fingers that realize these finger tip vectors 43 and 44 are calculated.

Then, each slave finger 3 uses the calculated joint angle as a command value.
To drive. As a result, the finger tip tip vector 5 of the master finger 2 is reproduced on the slave finger 3 as a slave finger tip tip vector 5 '.

Next, an embodiment in which the present invention is applied to a master-slave manipulator with four fingers will be described with reference to FIG.

In FIG. 3, the master side has three axes of the same structure as the master finger 25, 2 in which the thumb and forefinger are along the operator's finger.
6 and the middle finger and the third finger are in the shape of 3 facing the operator's finger.
The different-structure master fingers 27 and 28 of the axis. As a result, while maintaining the responsiveness of the master finger of the same structure and the ease of mounting and operability of the master finger of the different structure, the movable range of the thumb, which is the most important for human fingertip operation, can be widened. ing.

On the other hand, on the slave side, the fingers each consisting of two bent joints and one lateral swing joint are arranged parallel to each other, corresponding to the three fingers of the index finger, middle finger, and ring finger. A total of four fingers are provided with one finger 35 corresponding to a thumb having a coaxial structure at the opposite position.

In this embodiment, the base point of the vector between the finger tips is the index finger. Therefore, the control method of one finger to one finger, which focuses on the same joint angle as the conventional one, is adopted only for the control of the index finger, and the joint angle of the master index finger 26 is basically used. To the slave forefinger 36
It is reproduced as the joint angle of. Fingers other than the index finger are controlled by the present invention.

In FIG. 3, the control system detects each joint angle of the master index finger 26 by the angle detection unit 201, multiplies each joint angle by the coefficient a in the correction unit 202, or calculates such as coordinate conversion in the different structure master. Then, the command unit 203 commands each joint angle for the slave index finger 36 to drive them. Here, the reason why the correction unit 202 is used is that the joint angle of the master forefinger 26 is not used as it is as the joint angle of the slave forefinger 36, and the forefinger 36 serving as the origin is moved with the least discomfort.

On the other hand, the control system detects the joint angles of the thumb 35, middle finger 37, and ring finger 38 of the master by the angle detection unit 204, and calculates the finger tip position calculation unit.
At 205, the finger tip position of each finger is calculated. Also, from the joint angles of the master index finger 26 detected previously, the finger tip position calculation unit
At 206, the finger tip position of the master index finger 26 is calculated.

Next, in the finger tip-to-tip vector calculation unit 207, the master index fingers 25, 27, 28 and the master index finger are determined by the relationship between the finger tip position of the master index finger 26 and the finger tip positions of the other master fingers 25, 27, 28.
The finger tip vectors 51, 52, 53 between 26 are calculated, corrected by the correction unit 209 with the offset amount obtained by the offset calculation unit 208, and the finger tip vector setting unit 210 sets the finger tip vector of each slave finger. 51 ', 52', 53 '. Here, the correction unit 20
The reason for using 9 is that the fingers of the operator 1 do not come into close contact with each other even if the master fingers are moved until they come into contact with each other due to the difference in thickness between each master finger and the finger of the operator 1, etc. This is to eliminate the feeling of harmony, and an offset for compensating for the difference in thickness between the master finger and the operator's finger is set as the finger tip vector 51,5.
The operability is improved by various methods such as addition to 2,53.

Then, the control system uses the slave index finger 36 determined by the command unit 203.
From each joint angle, the finger tip position calculation unit 211 calculates the finger tip position of the slave index finger 36, and this slave index finger tip position and the other finger tips of the other slave fingers 35, 37, 38 between the finger tips of the slave index finger 36 are calculated. From the vectors 51 ', 52', 53 ', the finger tip position calculation unit 212 calculates the finger tip positions of the other slave fingers 35, 37, 38.

From the finger tip positions of the other slaves thus obtained, the joint angles of the respective fingers are calculated by the joint angle calculation unit 213, and with this as a command, the other slave fingers 35, 37, other than the human interface unit 36, Drive 38.

By the above, the operator 1 formed on each of the master fingers 25 to 28
The positional relationship between the tips of the fingers is surely reproduced as the tip relationship of the slave fingers 35 to 38. Therefore, the operation in which the human unconsciously controls the relative relationship between the fingers is reproduced on the slave, and it is possible to grip the object or manipulate the gripped object according to the image of the operator 1. Becomes That is, the operator 1 can cause the master-slave multi-finger manipulator to perform delicate or complicated work without special training.

FIG. 4 shows an example of the hardware configuration for implementing the control method according to the present invention, regarding the relationship between a reference finger and one other finger.

In FIG. 4, a master finger 60 is a reference finger, for example, a master index finger, and a joint angle detector such as a potentiometer.
61, 62, 63, each output is input as a joint angle command value to the position servo device 81, 82, 83 of each joint of the slave finger 80 corresponding to the master finger 60, and each position servo device 81, 82 , 83
Moves the joints so that the deviation between the joint angle detectors 84, 85, 86 provided at each joint and the joint angle command value becomes zero.

The master finger 70 is a finger such as a thumb other than the reference master finger 60, and has joint angle detectors 71, 72, 73.

The finger tip position calculator 64 calculates the finger tip position of the reference master finger 60, another finger tip position calculator 74 calculates the finger tip positions of the other master fingers 70, and the subtractor 65 subtracts these differences. The finger tip-to-tip vector between the two master fingers 60 and 70 is obtained.

Further, the finger tip position calculator 87 calculates the finger tip position of the slave finger 80 from each joint angle command value for the slave finger 80,
The adder 97 sets the finger tip position of the slave finger 80 and the master fingers 60, 70.
The finger tip position of the slave finger 90 corresponding to the master finger 70 is calculated from the inter-finger tip vector.

Then, each position / joint converter 98 converts the finger tip position of the slave finger 90 into each joint angle command value of the slave finger 90, and inputs it to the position servo devices 91, 92, 93 of each joint. There are joint angle detectors 94, 95, 96 at each joint of the slave finger 90, and each position servo device 91, 92, 93 has zero deviation between the detected angle of each joint of the slave finger 90 and the joint angle command value. Move the joint so that

If the number of fingers increases to 3 or 4, the number of arithmetic units should be increased accordingly.

<Effects of the Invention> According to the multi-finger manipulator control method of the present invention, the most important information when a person grips an object or manipulates the gripped object is [width of object] = [between finger tips]. Interval), pay attention to the finger tip positions of the master and slave fingers, and reproduce the finger tip vectors of the master as the finger tip vectors corresponding to the slave master. Can be moved according to the image of the operator.

Therefore, it is possible for a robot or the like to perform the detailed work that was conventionally impossible only by a human being, even if the operator is not specially trained. Therefore, for example, robots can safely perform complicated work in environments where humans cannot easily enter, such as in nuclear power plants, underwater, and space.

[Brief description of drawings]

FIG. 1 is a diagram showing a fundamental embodiment of the present invention, FIG. 2 is an explanatory diagram of a vector between finger tips, FIG. 3 is a diagram showing a concrete embodiment of the present invention, and FIG. FIG. 5 is a diagram showing a configuration example, FIG. 5 is a diagram showing a conventional control method, and FIG. 6 is a diagram showing an improved example of the conventional technique. In the drawing, 2, 25, 26, 27 and 28 are master fingers, 3, 35, 36, 37 and 38 are slave fingers, 5, 51, 52 and 53 are finger tip vectors of the master finger, and 5 ', 51 ′, 52 ′ and 53 ′ are finger tip vectors of slave fingers, 41 and 42 are finger tip vectors of master fingers, and 43 and 44 are finger tip vectors of slave fingers.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Maekawa 2-1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory Examiner Shinichi Shimada (56) Reference JP-A-61-54506 ( JP, A) JP-A-60-221277 (JP, A)

Claims (2)

[Claims] 1. In a master-slave multi-finger manipulator, the finger tip vector of each master finger is calculated from the joint angle of the master finger, and the finger tip vector of each master finger is calculated from the finger tip of each master finger. Calculating the vector, calculating the finger tip vector of each slave finger so that the finger tip vector of the slave fingers matches the corresponding finger tip vector of the master fingers, A method for controlling a multi-finger manipulator, comprising: calculating each joint angle of a slave finger, and driving the slave finger using the calculated joint angle as a command value. 2. In a master-slave multi-finger manipulator, a finger tip vector of each master finger is calculated from a joint angle of the master finger, and a specific one master finger is calculated from the finger tip vector of each master finger. Calculating a vector between finger tips of the master fingers based on the finger tip position; based on a joint angle of the specific one master finger, a joint of a specific one slave finger corresponding to the specific one master finger Calculating an angle, based on the finger tip-to-tip vector of the master fingers and the joint angle of the specific one slave finger, the slave fingers having the finger tip position of the specific one slave finger as a base point Calculating finger tip vectors of slave fingers other than the specific one slave finger so that the finger tip vectors correspond to the finger tip vectors of the corresponding master fingers; Calculate each joint angle of the slave fingers other than the specific one slave finger from the finger tip vector of the finger, and determine each slave finger including the specific one slave finger with the calculated joint angle as a command value. A method for controlling a multi-finger manipulator characterized by being driven.