JPH0428511B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to Which the Invention Pertains] This invention relates to a control device for a multi-jointed arm that can remotely perform simple work in a narrow space where humans cannot enter.

[Prior art and its problems]

Setting up large openings such as towers and tanks in shielded cells of nuclear fuel reprocessing plants or inside the reactor body of nuclear fusion reactors so that people can enter to inspect the interior or perform work. However, in facilities where this is not possible due to space limitations or safety restrictions such as high radiation areas,
There is a strong demand for the practical use of a device that allows a human operator to stay in a safe area, install only a machine that performs a predetermined work in the environment, and perform the work by remote control.

[Purpose of the invention]

An object of the present invention is to provide a multi-joint arm control device that allows inspection and work to be carried out under adverse environments by remote control without causing mental or physical burden on the driver.

[Summary of the invention]

The present invention is for controlling a multi-joint arm configured to connect a plurality of arms in series via joints and to control the joint angles of the connected joints, wherein the tip of the multi-joint arm is An attached television camera, a display means for displaying an image using a signal from the television camera, and a target point of the trajectory of the multi-joint arm is specified in the image displayed by the display means, and the multi-joint arm is moved. a target point coordinate measuring device that determines the direction of the target point from the tip; a rangefinder that is attached to the tip of the multi-jointed arm and measures the distance to an object on the optical axis of the lens of the television camera; The joint angles of the joints of the multi-joint arm are calculated by inputting the results measured by the meter and the direction determined by the target point coordinate measuring device so that all the joints of the multi-joint arm follow approximately the same trajectory. The multi-joint arm is equipped with a calculation means and a joint drive means for driving the joints based on the results obtained by the calculation means, and is capable of passing through even winding spaces to perform work. This is a multi-joint arm control device that drives the actual multi-joint arm while viewing a displayed image of the movement of the arm in order to guide the user to the destination point Q.

〔Effect of the invention〕

According to the present invention, by using a multi-joint arm, it is possible to perform work in a bad environment remotely while staying in a safe place.Moreover, controlling the movement of the multi-joint arm does not require skill and is easy. There are effects that can be controlled.

[Embodiments of the invention]

Examples of the present invention will be described in detail below.
FIG. 1 is a sectional view showing an example in which the multi-joint arm of the device of the present invention is applied to inspecting the inside of a heat exchanger of nuclear equipment.

This tank 1 has a narrow opening 2 at the entrance, and a group of piping 3 for a heat exchanger is arranged inside.The inside of the tank 1 cannot be seen directly from the opening 2;
A space is provided between the tank 1 and the inner wall of the tank 1 in which a television camera 16 for inspection and direction measurement of a target point attached to the tip S of the multi-jointed arm 4 and a working tool attached at the same location can be moved. It is being A distance meter 17 is installed near the television camera 16 to measure the distance to an object on the optical axis of the lens of the television camera. The multi-joint arm 4 has unit arms 5 ₁ , 5 ₂ ,...5 _o ,
joints 6 ₁ , 6 ₂ , which connect them in series;
..., 6 _o , and a moving device 7 that is movable while supporting the base of the multi-joint arm 4 so as to insert the entire multi-joint arm 4 into the tank ₁ . , 6 ₂ , ..., 6 _o each have a drive mechanism, and by controlling this drive mechanism, the joint angle θ can be changed. When the multi-joint arm 4 is pushed out by the moving device 7, the arm The tip S can be smoothly inserted to the destination point Q while watching the image on the display device so that the tip 5 does not come into contact with the inner wall of the tank 1 or the pipe group 3.

In other words, the control device for the multi-joint arm that can be inserted smoothly in this way is as shown in Figure 2.
Motors 8 ₁ to 8 _o for rotationally driving each joint,
Encoders 9 ₁ to 9 _o that measure the rotation angle of each cabinet section,
a motor 11 that drives the multi-joint arm movement mechanism 7;
Encoder 1 that measures the amount of movement of this motor 11
2 and a television camera 16 and a distance meter 17 attached to the tip S of the multi-joint arm 4, a motor drive control circuit 13, a computer 14, a computer input/output device 15, a monitor television 18, and a target point coordinate measuring device 1.
9 and a joystick 20.

The operation of the device of the present invention configured as described above is as follows.
To explain with reference to the specific flowchart shown in the figure and the explanatory diagram shown in Figure 4 to help understand this flowchart, first, the tip S of the television camera is located at P in Figure 4. Assuming that the position is at point ₀ , the driver first points the TV camera 16 at the joint 5 while looking at the scene inside the tank reflected on the monitor TV 18.
₁ by manual operation. Next, in the scene scene, determine an appropriate target point _R0 in the direction in which you want to move the tip S of the television camera 16, and aim at this point.

The aim is, for example, a crosshair cursor superimposed on the image on the television monitor 18, and this cursor can be freely moved to any position on the television monitor with a joy stick. Target point coordinate measuring device 19
has a function of creating the cursor and automatically measuring the coordinates of the cursor on the monitor.

After aiming at the target point R ₀ , the driver instructs the computer 14 to read the coordinate values of the cursor on the monitor image using the computer input/output device 15 . If the cursor is not at the center of the monitor image, calculate the rotation angle of joint 5 ₁ from its coordinate values,
By rotating the joint ₅₁ , the direction of the television camera 16 is changed, and automatic control is performed so that the target point _R0 is placed in the center of the monitor image. This means that the television camera is correctly pointing in the direction of the target point R ₀ .

When the above operations are completed, the distance to the target point is automatically measured.

Since the distance meter 17 is attached to measure the distance to an object on the optical axis of the television camera, it measures the distance up to R ₀ , which is the closest point as seen from the television camera. The rangefinder 17 may be either an optical type or an ultrasonic type used in automatic focusing cameras, for example. The distance measurement value is automatically read into the computer 14, and the computer input/output device 1
The value is output to 5.

The driver looks at this distance value and the image displayed on the monitor television 18, judges how far the tip of the television camera 16 should be advanced in the direction of _R0 , and inputs the value l into the computer input/output device. 15 to the computer 14.

Next, the calculator 14 calculates the rotation angle [θ] of each joint 5 ₁ to 5 _o necessary to move the tip of the television camera 16 by a distance l in the direction of R ₀ , and then transmits the command signal to the motor drive circuit. Output to 13. In this case, a command is issued to the multi-joint arm moving mechanism 7 to move by a distance l.

As a result, the tip S of the television camera 16 is at point P ₁
Move until.

Thereafter, by repeating the same procedure as sequentially setting the target point to R ₁ and reaching P ₂ , and setting it to R ₂ and reaching P ₃ , the target point is reached to the tip of the television camera 16, P ₈ . , and finally, by manually controlling the direction of the TV camera 16 as necessary, drive the joint 5 ₁ to set the Q
All you have to do is point in the direction of the point and bring point Q to the center of the image. In this case, it is also possible to use the cursor mentioned above to aim at the final target point Q, input its coordinate values into the computer, and automatically direct the camera in the direction of the Q point.

When controlling the multi-joint arm 6 as described above,
[θ] is determined so that the trajectory of each joint 5 ₁ to 5 _o lies as much as possible on the polygonal line connecting the points P ₀ to P _o with a straight line, so that the multi-joint arm 6 does not collide with surrounding objects. control. Specifically, for example, when the tip of the television camera moves from point P ₄ to point P ₅ , each joint of 5 ₁ to 5 _o should be moved as much as possible on the line of _{0 1} , _{1 2} , _{2 3} [θ ].

In order to make it easier to understand the content of the invention, the purpose of the invention was explained using an example of a multi-joint arm that moves within a two-dimensional plane. However, if a multi-joint arm with two degrees of freedom per joint is used, three It is possible to construct a remote control device that can freely move within dimensional space.

In addition, we used an example of an inspection device with a television camera attached to the end of a multi-joint arm, but if the end is equipped with a torque wrench, gripper, or magnetic chuck, it can be used to tighten nuts and collect loose parts. Can perform simple tasks.

[Brief explanation of drawings]

Fig. 1 is a sectional view explaining the outline of the present invention, Fig. 2
3 is a block diagram explaining the configuration of the present invention, FIG. 3 is a control flowchart of the apparatus of the present invention, and FIG. 4 is an explanatory diagram to help understand FIG. 3. 4 ¹ ~ 4 _o ... unit arm, 5 ₁ ~ 5 _o ... joint,
6... Multi-joint arm, 7... Multi-joint arm moving mechanism, 8 ¹ to 8 _o ... Motor, 9 ₁ to 9 _o ... Encoder, 11... Motor, 12... Encoder, 13
...Motor drive circuit, 14...Calculator, 15...
Computer input/output device, 16...TV camera, 17
... Distance meter, 18 ... Monitor television, 19 ... Target point coordinate measuring device, 20 ... Joystick,
21...control device.

Claims (1)

[Scope of Claims] 1. A multi-joint arm control device configured to connect a plurality of arms in series via joints and to control the joint angles of the connected joints, comprising: a television camera attached to the tip; a display means for displaying an image using signals from the television camera; a target point coordinate measuring device for determining the direction from the tip of the multi-joint arm to the target point on the trajectory; and a device for measuring the distance to an object attached to the tip of the multi-joint arm and on the optical axis of the lens of the television camera. A rangefinder, the results measured by the rangefinder, and the direction determined by the target point coordinate measuring device are input, and each joint of the multi-joint arm is adjusted so that all the joints follow approximately the same trajectory. A multi-joint arm control device comprising: a calculation means for calculating a joint angle of the joint; and a joint drive means for driving the joint based on the result obtained by the calculation means.