JPH05126657A - Multi-degree-of-freedom robot - Google Patents

Abstract

PURPOSE:To provide a multi-degree-of-freedom robot capable of detecting the external force applied to the corresponding portion of each degree of freedom of this robot for each degree of freedom with few force detectors. CONSTITUTION:The robot has a force detector 9 detecting the action of the corresponding portion of the detection degree of freedom 1 within (n) degrees of freedom, where n>=2, an interfering means 23 transferring the actions among the corresponding portions of the other (n-1) degrees of freedom 4 and the actions between the corresponding portions of the other (n-1) degrees of freedom 4 and the corresponding portion of the detection degree of freedom 1, and an arithmetic means 24 calculating the external force F applied to the corresponding portions of the other (n-1) degrees of freedom 4 based on the detection value detected by the force detector 9. The force detector 9 detects the force transferred to the corresponding portion of the detection degree of freedom 1 when the external force F is applied to either one of the corresponding portions of the other (n-1) degrees of freedom 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-degree-of-freedom robot, and more particularly to a multi-degree-of-freedom robot equipped with a force detector for detecting a force acting on an arm of the robot.

[0002]

2. Description of the Related Art In order to avoid a collision between arms of a multi-degree-of-freedom robot and a collision between an arm and another object, force control such as stiffness control is used.
In these controls, a sensor that detects a force component in the collision direction is required.

[0003]

However, when using force control such as stiffness control in a robot having multiple degrees of freedom, it is necessary to dispose a sensor for each degree of freedom in order to detect the collision direction. Therefore, there are problems that the number of arranged sensors becomes large, the structure of the robot becomes complicated, and the cost also rises.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to use a small number of force detectors to detect an external force acting on a portion corresponding to each degree of freedom of a robot having multiple degrees of freedom. It is to provide a multi-degree-of-freedom robot that can detect each degree of freedom.

In addition, a multi-degree-of-freedom that can avoid a collision by detecting an external force acting on a corresponding part of each degree of freedom of a multi-degree-of-freedom robot for each degree of freedom by using a small number of force detectors. It is to provide a robot.

[0006]

In order to achieve the above object, the present invention provides a corresponding portion of a detection degree of freedom which is one of n (n ≧ 2) degrees of freedom of a multi-degree-of-freedom robot. Between the force detector for detecting the motion of the other and the corresponding part of the other (n-1) degrees of freedom, and the corresponding part of the other (n-1) degrees of freedom and the detection degree of freedom. Interference means for transmitting motion between corresponding parts, and calculation for calculating the force received from the outside by each of the other (n-1) degrees of freedom corresponding parts from the detection value detected by the force detector. In the force detector, the force received from the outside by any of the other (n-1) corresponding portions having the degree of freedom is transmitted to the corresponding portion having the detection degree of freedom, and is transmitted to the corresponding portion. It is characterized by detecting force.

[0007]

When a force is applied from the outside to a portion corresponding to any one of the n (n ≧ 2) degrees of freedom of the multi-degree-of-freedom robot, the force is transmitted to the other (n-1) degrees of freedom by the interference means. .
This force is detected by a force detector attached to the corresponding portion of the detection degree of freedom, and from the detection value of the force detector, the force received from the outside by the corresponding portion of each of the other (n-1) degrees of freedom is detected. Calculate

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multi-degree-of-freedom robot according to the present invention will be described below with reference to FIGS.

A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

First, the general construction of the first embodiment will be described with reference to FIG. In FIG. 2, in the multi-degree-of-freedom robot 20 having n degrees of freedom or more, n (n ≧
2) One of the degrees of freedom is set as the detection degree of freedom 21, and a force detector 9 is attached to a portion corresponding to the detection degree of freedom 21. In addition, an interference means 23 for transmitting a force to each other is provided between the n corresponding portions having the respective degrees of freedom 21 and 22.
When any of the corresponding parts of the (n-1) degrees of freedom 22 other than the detection degree of freedom 21 receives a direct force from the outside due to a collision or the like, this force is detected via the interference means 23.
Is transmitted to the corresponding site. The transmitted force is attached to the corresponding portion of the detection degree of freedom 21 and detected by the force detector 9. In addition, other than the detection degree of freedom 21 (n-
1) Calculation means 24 for calculating the force that the corresponding portion of each of the degrees of freedom 22 receives from the outside through the interference means 23.
Is provided. In the calculation means 24, the interference means 2
It is calculated from the detection value of the force detector 9 by using the known data regarding the method of transmitting the force between the respective degrees of freedom when 3 is used.

Next, a specific example of the first embodiment will be described with reference to FIG.

In FIG. 1, a robot having two degrees of freedom is shown. A first shaft 1 is attached to a base 10, a first arm 2 is rotatably attached to the first shaft 1, and a first arm 1 is attached. The second shaft 4 is attached to the tip of the second shaft 4.
A second arm 5 is rotatably attached to the, and an extension 7 of the second arm 5 is attached with a hand 7 for working on a work target.

A first pulley 3 is attached to the first shaft 1, a second pulley 6 is attached to the second shaft 4, and an interference belt 8 is provided between the first pulley 3 and the second pulley 6. It is connected. The first pulley 3, the second pulley 6 and the interference belt 8 form an interference means 23.

Further, a force detector 9 is attached to the outer circumference of the first pulley 3. The interference belt 8 is adapted to wind around the detection surface of the force detector 9.
The tension T ₁ of the interference belt 8 is detected by.

The interference matrix of the interference means 23 is obtained by the equation (1).

[0016]

[Equation 1] Here, θ ₁ represents the current value of the rotation angle of the first shaft 1 before the operations of the first shaft 1 and the second shaft 4 receive an external force and interfere with each other, and θ ₁
′ Indicates the present value of the rotation angle of the first shaft 1 after the operations of the first shaft 1 and the second shaft 4 interfere with each other by receiving an external force. Similarly, θ ₂ and θ ₂ ′ represent the current values of the rotation angle of the second shaft 4 before and after the operations of the first shaft 1 and the second shaft 4 interfere with each other by receiving an external force.

Further, r10 and r20 represent the radii of the first pulley 3 and the second pulley 6, respectively.

Next, according to equation (1), θ ₁ ′ and θ ₂ ′,
And the result of performing stiffness control on the motor speed command value θ ₁ volt of the motor for driving the first shaft 1 using the tension T ₁ of the interference belt 8 detected by the force detector 9 in the formula (2). Show. Similarly, the result of performing the position control on the motor speed command value θ ₂ volt of the motor that drives the second shaft 4 is shown in Expression (3).

Θ ₁ volt = Kp · (θ ₁ ref−θ ₁ ′) + Ks · T ₁ (2) θ ₂ volt = Kp · (θ ₂ ref−θ ₂ ′) (3) where Kp is position control Gain, Ks is a stiffness control gain, and θ ₁ ref and θ ₂ ref are control target values of the rotation angles of the first shaft 1 and the second shaft 4, respectively.

Next, the operation of this embodiment will be described.

It is assumed that an external force F is applied to the robot from the outside in an arbitrary direction due to a collision or the like.

(1) When the external force F is applied to the corresponding portion of the first shaft 1 In this case, the influence of the external force F can be directly detected by the force detector 9 regardless of the second shaft 4. This tension T ₁
Is detected by the force detector 9, and the first arm 2 can be rotationally moved to a position where the tension T ₁ is balanced with a predetermined component of the external force F by stiffness control using the equation (2). (2) When the external force F is applied to the corresponding portion of the second shaft 4, in this case, when the external force F is applied, the second pulley 6 of the second shaft 4 is applied.
A torque is applied to the tension belt ₁ and a tension T ₁ is generated via the interference belt 8. The first shaft 1 rotates to a position where the tension T ₁ balances with a predetermined component of the external force F by the stiffness control.
At this time, at the same time, the second shaft 4 rotates via the interference belt 8, so that the second shaft 4 can rotate as if controlled by the stiffness control.

According to the construction of this embodiment, the interference means 23 is provided, so that the external force F acting on the corresponding portions of the shafts 1 and 4 can be detected by using one force detector 9. You can

Next, another embodiment of the present invention will be described with reference to FIG.

In FIG. 3, one multi-degree-of-freedom robot 20 shown in FIG. 2 corresponds to one degree of freedom and corresponds to one arm. Further, in the present embodiment, the result of the calculation means 24 is sent to the drive means 25. The drive means 25 cancels the force that the detection arm 21a and the transmission arm 22a receive from the outside based on the force on the detection arm 21a determined by the force detector 22 and the force on the transmission arm 22a determined by the calculation means 24. Then, the detection arm 21a and each transmission arm 22a are driven.

According to the present embodiment, since the driving means 25 is provided, the arm exerted on the multi-degree-of-freedom robot 20 is offset so as to cancel the force applied from the outside due to a collision or the like to avoid the influence of the collision or the like. Can be controlled.

The driving means 25 finds the arm that directly receives the force F from the outside based on the force on the detection arm 21a obtained by the force detector 9 and the force on the transmission arm 22a obtained by the computing means 24. The arm may be moved so as to cancel the force F received from the outside.

[0028]

As described above, according to the structure of the present invention, the external force acting on the arm of a robot having multiple degrees of freedom is detected for each degree of freedom by using a small number of force detectors. can do. Further, it is possible to avoid the collision by detecting the external force acting on the robot arm having multiple degrees of freedom for each degree of freedom by using a small number of force detectors.

[Brief description of drawings]

FIG. 1 is a perspective view showing a specific configuration of a first embodiment of a multi-degree-of-freedom robot according to the present invention.

FIG. 2 is a block diagram of a first embodiment of a multi-degree-of-freedom robot according to the present invention.

FIG. 3 is a block diagram of a second embodiment of a multi-degree-of-freedom robot according to the present invention.

[Explanation of symbols]

 1 1st axis 2 1st arm 3 1st pulley 4 2nd axis 5 2nd arm 6 2nd pulley 7 Hands 8 Interference belt 9 Force detector 10 Base 21 Detection degree of freedom 21a Detection arm 23 Interference means 24 Computing means 25 Drive means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Ogawa Inventor Hideki Ogawa 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Research Institute Ltd. Muko Toshiba Town 1 Stock Company Toshiba Research Institute

Claims (2)

[Claims] 1. A force detector for detecting a motion of a part corresponding to a detection degree of freedom, which is one of n (n ≧ 2) degrees of freedom of a multi-degree-of-freedom robot, and another (n-1). ) Interfering means for transmitting motion between corresponding parts of the degrees of freedom and between other (n-1) corresponding parts of the degrees of freedom and the corresponding parts of the detection degrees of freedom, and the force detection. The force detector receives a force externally applied to each of the other (n-1) degrees of freedom corresponding to the detected value detected by the detector. -1) A multi-degree-of-freedom robot, characterized in that a force received from the outside by any of the corresponding parts having the degree of freedom is transmitted to the corresponding part having the detection degree of freedom, and the transmitted force is detected. 2. A detection arm having a force detector attached thereto, at least one transmission arm having no force detector attached thereto, an operation between the detection arm and the transmission arm, and an operation between the transmission arms. And an operation means for calculating the force received by each of the transmission arms from the outside based on the detection value detected by the force detector, and the force detector includes one of the transmission arms. A multi-degree-of-freedom robot in which a force received from the outside is transmitted to the detection arm and the transmitted force is detected.