JP3333874B2 - Lever-parallel link position / posture transmission mechanism and manipulator having lever-parallel link position / posture transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lever-parallel link position / posture transmission mechanism provided between an arm and an end effector and transmitting the position / posture of the arm to the end effector in a manipulator having an arm and an end effector. Things. Such a position and orientation transmission mechanism can be applied to an industrial manipulator, a surgical manipulator, particularly a surgical manipulator in an MRI environment.

[0002]

2. Description of the Related Art Various types of manipulators have been developed and used in industry. On the other hand, manipulators are expected to be applied to the medical field for the purpose of improving surgical treatment and diagnosis, making them less invasive, and reducing costs.

However, conventional industrial manipulators are intended for use in factories, and are therefore premised on use in an environment isolated from humans. Therefore, in the conversion to medical use, design of special mechanisms and control methods that take into account the effects of safety for patients and operators, sterilization, electric shock, and mutual noise to and from other medical devices Is required.

[0004] Further, it is considered that a surgical manipulator is used under X-ray CT or MRI image guidance, but these imaging devices have a narrow opening. In addition, the surgical manipulator must not hinder the operator's work because the operator's intervention is required. Therefore, a manipulator having a low space occupancy is required.

[0005] Manipulators are mainly classified into serial mechanisms and parallel mechanisms. In the serial mechanism, each link is connected in series, each joint has a rotational degree of freedom, and a movable range is large. However, if the manipulator goes out of control, it may damage everything included in the range of motion, so in the case of a surgical manipulator,
On the contrary, it becomes disadvantageous. For this reason, the movable range needs to be managed mechanically. Further, in the case of the serial mechanism, the intermediate link such as the elbow joint largely moves, which may cause a risk of interfering with the patient / operator, which is dangerous.

On the other hand, the parallel mechanism is a type in which a base to an end plate are connected in parallel by a plurality of links. The management of intermediate links is relatively easy on parallel mechanisms, especially on Stewart platforms. However, the base plate must be large in order to expand the movable range and counter the lateral forces and moments, and since multiple links are connected in parallel, the space occupied by the intermediate links is inevitably large. . If this manipulator is near the patient, the manipulator occupies the space where the operator works.

Further, from the viewpoint of sterilization and reduction of noise from other medical devices or from other medical devices, the actuators and control circuits need to be far from the working space. Today, manipulators used in an MRI environment are required. In this case, electric devices and magnetic materials cannot be used in the work space, so a mechanism for remotely transmitting the driving force is required.

[0008]

SUMMARY OF THE INVENTION
The manipulator's movable range can be controlled mechanically, the space occupancy of the manipulator in the work space is low, the manipulator can be sterilized, and the influence of mutual noise between the manipulator and other medical devices can be reduced to reduce the MRI environment There is a need to develop a manipulator that can be used below.

The present invention has been made in view of the above circumstances, and by transmitting a driving force from a remote place by a motion transmitting mechanism, the space occupancy in the working space is low, and the manipulator can be sterilized. It is an object of the present invention to provide a manipulator that can reduce mutual noise with other medical devices and that can be used in an MRI environment.

[0010]

According to this object, a manipulator having a lever-parallel link position / posture transmission mechanism and a lever-parallel link position / posture transmission mechanism according to the present invention is provided in a work space.
An end effector acting on an object in the area, and an arm mechanism performing a movement for determining the position and orientation of the end effector. The manipulator is provided between the arm mechanism and the end effector, and controls the movement of the arm mechanism. A position and orientation transmission mechanism for transmitting to an end effector, wherein the position and orientation transmission mechanism includes a first link member fixed to the arm mechanism, a second link member fixed to the end effector, and the arm mechanism.
Second universal to the second link member linked other end via a first universal joint to one end of the longitudinal axis direction of the first link member forms a straight shape having a length which is separated from the work area A third link member of a rigid body connected via a joint, a link between the first link member and the second link member, and a longitudinal axis of the third link member; A fourth link member that is arranged in parallel with the first link member and that transmits a parallel motion between the first link member and the second link member; and a fourth link member on the third link member. To allow a lever movement movably along the longitudinal axis and rotatable about the longitudinal axis and about two axes orthogonal to the longitudinal axis;
And a rigid and fixed fifth link member that supports the third link member.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings with reference to one embodiment.

FIG. 1 shows an embodiment in which the position and orientation transmission mechanism of the present invention is applied to a Stewart platform type manipulator.

1 to 4, reference numeral 1 denotes a lever-parallel link type position / posture transmission mechanism (hereinafter simply referred to as a position / posture transmission mechanism, which is the same in the embodiment). The position and orientation transmission mechanism 1 is attached to a stewart platform type manipulator (hereinafter simply referred to as a manipulator, the same in the embodiment). The manipulator 2 has an arm 3 and an end effector 4,
The position and orientation transmission mechanism 1 is provided between the arm 3 and the end effector 4, and the first link member 5 at one end connects the arm 3 to the end effector 4.
Is fixed to an end plate 6 which is a distal member of the base member, and is fixed to a base end member 8 to which the end effector 4 is attached by a second link member 7 at the other end. Since the first link member 5 and the end plate 6 are fixed and there is no relative movement between them, the second link member 7 and the base end member 8 are fixed and the relative movement is between them. 1 to 4
, The first link member 5 and the end plate 6 are shown as the same member, and the second link member 7
And the base member 8 are shown as the same member.

As shown in FIGS. 5 to 7, the manipulator 2 includes an arm 3 extending from a fixed base plate 11 to a movable end plate 6 , and includes a plurality of links 12a to 12a.
2f. Links 12a-12
f is constituted by a linear actuator. Link 1
2a to 12f, base plate 11, end plate 6
And are connected by a ball joint 14. By controlling the expansion and contraction of the links 12a to 12f, it is possible to cause the end plate 6 to take any position and posture in the set movable range. The position and orientation transmission mechanism 1 of the present invention transmits the position and orientation of the end plate 6 to the end effector 4. End effect
Is the part that directly acts on the object, and the arm is the end
The part that moves to determine the position and orientation of the effector
You.

As shown in FIGS. 8 to 12, the position and orientation transmission mechanism 1 has a first link member 5 and a second link member 7 located at both ends of the manipulator 2. The first link member 5 is a member that is fixed to the arm 3 of the manipulator 2, and functions as an input-side end that inputs the movement from the arm 3 of the manipulator 2 to the position / posture transmission mechanism 1. The second link member 7 is a part that functions as an output end that outputs the movement of the position and orientation transmission mechanism 1 to the end effector 4.

The position / posture transmission mechanism 1 includes a third link member 1
5 The third link member 15 is in the form of a rigid rod, and a substantially central portion 18 which forms a connecting portion 17 to a fixed link 16 described later has a round bar shape, and
1 to form a pair 22 which is slipped around.

Three orthogonal x-axes on the third link member 15;
Among the y-axis and the z-axis, the first link member 5 is connected to one end in the longitudinal z-axis direction of the third link member 15 via the first universal joint 23, and to the other end in the z-axis direction. The second link member 7 is connected via a second universal joint 24.

Around the third link member 15, three fourth link members 25 are arranged in parallel with the Z axis of the third link member 15 , and this constitutes a parallel link mechanism.
You. The three fourth link members 25 are made of a material such as a wire or a rod that can bear the tension, and are connected to the first link member 5 at one end via a joint 26 at both ends and to the second link at the other end. It is connected to the member 7. If the fourth link member 25 is a rod that can bear both tension and compression force, two rods are sufficient. In the case of three, the three joints must not be in line and one point must be on the opposite side of the universal joint. In the case of two, the universal joint and the two joints must not be aligned. In order for the third link member 15 and the fourth link member 25 to always keep parallel, the relative positions of the universal joints 23 and 24, which are the centers of rotation, and the joint 26 must be equal. Each fourth link member 25
The joint 26 between the first link member 5 and the second link member 7 can rotate about three orthogonal axes.

When the fourth link member 25 is a wire, the wire itself is flexible with respect to rotation about three orthogonal axes, so that the wire is connected to the first link member 5 and the second link member 7. However, when the fourth link member 25 is a rigid rod, a ball joint is used for the joint between the fourth link member 25 and the first link member 5 and the second link member 7. Must be used.
The first link member 5, the second link member 7, the third link member 15, and the fourth link member 25 are a first link portion.
Causing a relative parallel movement between the member 5 and the second link member 7
Constitute a parallel link Organization.

The third link member 15 is supported by a fixed link 16 as a fifth link member via a third universal joint 27 and a pair of swivels 22. The swivel pair 22 is formed between the central portion 18 of the third link member 15 and the cylindrical slider 21 fitted therein, so that the third link member 15 has a linear displacement in the Z-axis direction. Rotational displacement about the Z axis is possible.

The third universal joint 27 is formed between the slider 21 and the fixed link 16,
The base end of the gimbal 31 has three orthogonal axes on the fixed link 16,
It is attached so as to be rotatable around a longitudinal Z axis of the X axis, the Y axis, and the Z axis. The gimbal has a two-pronged tip which pivots around a pair 22 to form a fixed link 16-.
The gimbal 31 can rotate around an axis perpendicular to the rotation axis.

As a result, due to the gimbal 31 and the sliding pair 22, the third link member 15 moves around the Z-axis, which is three orthogonal axes with the longitudinal direction of the link member 15 as the Z-axis direction. , X-axis and Y-axis, and can be linearly displaced in the Z-axis direction. No.
Rotation of link member 15 around X axis and rotation around Y axis
Is the lever movement of the third link member 15.

In the lever-parallel link position / posture transmission mechanism 1 configured as described above, the manipulator 2
The movement input from the arm 3 is output to the end effector 4, but the input from the arm 3 causes the first link member 5 to be linearly displaced in the X-axis, Y-axis, and Z-axis directions. The robot makes a six-degree-of-freedom motion with a rotational displacement about the three axes. The motion having six degrees of freedom is transmitted to the second link member 7. That is, the displacement of the first link member 5 in the X-axis direction is caused by the rotation of the third universal joint 27 about the Y-axis between the third link member 15 and the fourth link member 16, thereby causing the second link to rotate. This appears as a linear displacement of the member 7 in the direction opposite to the X-axis direction. Next, the first link member 5
Is displaced in the Y-axis direction by the third universal joint 27.
Of the second link member 7 appears as a linear displacement in the opposite direction of the Y-axis direction.

Next, the displacement of the first link member 5 in the Z-axis direction is caused by the third link member 15 rotating in the same direction in the Z-axis direction of the second link member 7 by linear sliding displacement with respect to the pair 22. Appears as a linear displacement of Since the first link member 5, the second link member 7, the third link member 15, and the fourth link member 25 constitute the parallel link mechanism 31 at the time of this three-axis linear displacement, The link member 5 and the second link member 7 make a parallel motion.

Next, when the first link member 5 rotates around the X axis and the Y axis, the movement appears as rotation of the second link member 7 around the X axis and the Y axis by the parallel link mechanism 31. When the first link member 5 rotates around the Z-axis, the movement is transmitted to the second link member 7 as the third link member 15 rotates around the Z-axis, and the second link member 7 Rotate around an axis.

In this manner, all the movements of the first link member 5 in six degrees of freedom appear as the movements of the second link member 7 in six degrees of freedom, which are transmitted to the end effector 4 attached to the second link member 7. Is done. However, the direction of the linear motion with the rotation of the fourth universal joint 27 around the X axis and the Y axis is determined by the first link member 5 and the second link member 7.
Is the opposite. In the embodiment described above, the position and orientation transmission mechanism is applied to a Stewart platform type manipulator. However, the position and orientation transmission mechanism of the present invention can be applied to other parallel mechanisms and serial mechanisms.

[0027]

The feature of the present manipulator is that the operation of the manipulator can be transmitted to the opposite side of the universal joint by the lever-parallel link position / posture transmission mechanism 1. Since only one lever made of the third link member 15 is contained in the work area, the space occupancy is low and does not hinder the operation of the operator. That is, the transmission of the present invention
In the case of the reaching mechanism, the working area is moved from the third link member 15
In other words, a parallel link mechanism
Only the combination of the fourth link member 25
It is. The third link member and the fourth link member are true
It is a straight and long body, there is no elbow joint in the middle,
Workers can work safely without anything. In addition, this transmission mechanism
The manipulator that drives the
Arm type and parallel mechanism type
Can be used without any problem. On the other hand, since the operating range of the manipulator is far from the work area, the manipulator can be used with an elbow joint such as a serial mechanism or with a high space occupancy such as a parallel mechanism.

As for the management of the movable area, the movable area can be limited by providing a wall or the like in the movable area on the manipulator side. Excessive speed is dangerous, but the speed can be limited by attaching a damper to the manipulator. By thus restricting the input side of the lever-parallel link position / posture transmission mechanism 1, it is possible to enhance both safety and workability without installing anything on the output side.

Since the actuator can be placed far from the work area, it can be easily applied to a manipulator in an MRI environment.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view showing a state in which a lever-parallel link position / posture transmission mechanism of the present invention is incorporated in a manipulator.

FIG. 2 is an explanatory front view of the manipulator 2;

FIG. 3 is an explanatory side view of the manipulator 2;

FIG. 4 is an explanatory sectional view taken along a line aa ′ in FIG. 2;

FIG. 5 is an explanatory front view showing a state in which the lever-parallel link position / posture transmission mechanism 1 of the present invention is incorporated in the manipulator 2;

FIG. 6 is an explanatory side view showing a state in which the lever-parallel link type position / posture transmission mechanism 1 of the present invention is incorporated in the manipulator 2;

FIG. 7 is an explanatory sectional view taken along the line aa ′ in FIG. 5;

FIG. 8 is an explanatory front view of the lever-parallel link position / posture transmission mechanism 1.

FIG. 9 is an explanatory side view of the lever / parallel link position / posture transmission mechanism 1;

FIG. 10 is an explanatory sectional view taken along the line aa ′ in FIG. 8;

FIG. 11 is an explanatory sectional view taken along the line bb ′ in FIG. 8;

FIG. 12 is an explanatory cross-sectional view taken along the line cc ′ in FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 lever-parallel link position / posture transmission mechanism 2 Stewart platform type manipulator 3 arm 4 end effector 5 first link member 6 end plate 7 second link member 8 base end member 11 base plate 12 af link 13 a, 13b, 13c pair 14 Ball joint 15 Third link member 16 Fixed link 17 Connection part 18 Central part 21 Slider 22 Swivel pair 23 First universal joint 24 Second universal joint 25 Fourth link member 26 Step 27 4 universal joints 34 parallel link mechanism

──────────────────────────────────────────────────続 き Continuing from the front page Examiner Masaaki Sasaki (56) References JP-A-52-37365 (JP, A) JP-A-51-158569 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) B25J 11/00

Claims (4)

(57) [Claims] 1. An arm mechanism provided between an end mechanism and an arm mechanism for determining a 6-degree-of-freedom position / posture.
A position and posture transmission mechanism for transmitting the movement of the end effector to the end effector, the position and posture transmission mechanism comprising: a first link member fixed to the arm mechanism; a second link member fixed to the end effector; A rigid body that forms a rod-like body and has one longitudinal end connected to the first link member via a first universal joint and the other end connected to the second link member via a second universal joint. The third link member, which connects the first link member and the second link member, and is disposed parallel to the longitudinal axis of the third link member; A fourth link member that constitutes a parallel link mechanism that transmits a parallel movement between the second link member and the second link member; And characterized in that it comprises a fifth link member rotatably and and fixed rigid for rotatably supporting the third link member about two axes perpendicular to the longitudinal axis around the longitudinal axis Leverage-Parallel Lin type position and orientation transmission mechanism. 2. The lever-parallel link position / posture transmission mechanism according to claim 2, wherein said manipulator is a medical manipulator. 3. An arm mechanism provided between an end effector and an arm mechanism for determining a 6- degree-of-freedom position / posture .
A parallel link type position / posture transmission mechanism having a position / posture transmission mechanism for transmitting a movement to the end effector, wherein the position / posture transmission mechanism comprises: a first link member fixed to the arm mechanism; A fixed second link member, a rod-shaped body, and one end in the longitudinal axis direction are connected to the first link member via a first universal joint, and the other end is connected to the second link member with a second link member. A rigid third link member connected via a universal joint, the first link member and the second link member being connected, and being arranged parallel to the longitudinal axis of the third link member; A fourth link member that constitutes a parallel link mechanism that transmits a parallel motion between the first link member and the second link member; and the third link portion. Along said longitudinal axis of the upper is movably and rotatably and and fixed rigid for rotatably supporting the third link member about two axes perpendicular to the longitudinal axis about said longitudinal axis A manipulator having a lever-parallel phosphorus position / posture transmission mechanism, comprising: a fifth link member; 4. The lever according to claim 3, wherein said manipulator is a medical manipulator.
A manipulator having a parallel link type position and orientation transmission mechanism.