JPH0512110B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a device that remotely performs simple work in a narrow space where humans cannot enter. [Prior art and its problems] A large opening is installed and a person can enter and inspect the interior, such as in the towers and tanks in the radiation-shielded cells of a nuclear fuel reprocessing plant or inside the reactor body of a fusion reactor. In facilities where it is impossible to carry out light or simple tasks due to space limitations or safety restrictions such as areas with high radiation levels, human workers must be in a safe area and carry out designated tasks. There is a strong desire to put into practical use a device that allows only the machine that performs the work to be installed in the environment described above and to perform the work by remote control. For example, a case will be described in which a pipe H having many bends as shown in FIG. 1 is to be inspected. Note that in order to make the explanation easier to understand, a two-dimensional space will be used as an example. If there is a leak near point Q in the piping system and an attempt is made to inspect point Q from the inside, it is impossible to directly view point Q from the opening (flange) K. Further, if the piping system H is too thin for humans to enter, or if the inner surface of the piping system is contaminated with radioactive substances and cannot be accessed by humans, such an inspection becomes impossible. [Object of the Invention] An object of the present invention is to provide a multi-joint arm device that can perform inspections and simple tasks under adverse environments by remote control without causing mental or physical burden on the driver. [Summary of the Invention] The present invention provides a multi-joint arm formed by connecting a plurality of arms via joints, a moving means for moving the entire multi-joint arm, and an arm provided at the tip of the multi-joint arm. A distance measuring means consisting of a signal generating element and a signal receiving element, which measures the distance to obstacles around the device, and an arm tip that avoids contact with obstacles based on the distance information obtained by this distance measuring means. and control means for operating the multi-joint arm by controlling the joint angle of the joint and the amount of movement by the moving means so that the target movement point becomes the movement target point of the joint. This is a multi-joint arm control device. [Effects of the Invention] According to the present invention, since the front and sides of the most advanced arm are automatically monitored and controlled, the driver can safely work in a narrow space in a bad environment that was previously impossible. The system can be operated remotely from anywhere, and is particularly effective in nuclear power facilities where reducing the radiation exposure of workers is of paramount importance. [Embodiments of the Invention] Examples of the present invention will be described in detail below. The embodiment of the present invention is applied to a multi-joint arm device as shown in FIG. A multi-joint arm 1 that can pass through even a twisted space, and unit arms 1 ₁ , 1 ₂ , . . . that constitute this multi-joint arm.
Joint 2 connecting 1n+1 and the most advanced arm 1 ₁
An imaging device (television camera) 3 attached to the front, a front rangefinder 4 and a side rangefinder 5, a TV monitor 6 that displays images from the TV camera 3, and a multi-joint arm 1 supporting the base of the multi-joint arm 1. This is a remote-controlled device consisting of a multi-joint arm moving mechanism 7 for moving the entire body of the multi-joint arm, and a control drive section 8 for controlling these. This signal is used to automatically avoid obstacles and allow the tip of the multi-jointed arm to reach the Q point as shown in Figure 1 for inspection. This is what I did. The drive of this multi-joint arm device is controlled by a control circuit 9 as shown in FIG. This control circuit 9 drives the motors 10 ₁ , 10 ₂ , . . . 10n that move the joints _{2 1} , _{2 2} , . The computer includes a motor drive circuit 12 that drives the motor 11, a computer 13 that inputs control signals to the motor drive circuit 12, and a computer input/output device 14 that controls input and output of the computer 13. Also, the rotation angle of each joint 2 ₁ , 2 ₂ , ... 2n is determined by encoders 15 ₁ , 15 ₂ , 2n provided at each joint.
... is input to the computer 13 as an output signal of 15n. Furthermore, the front rangefinder 4 and the side rangefinder 5 ₁ ,
The output signals of 5 ₂ , ... 5 ₈ are sent to a distance measuring device 1 that sequentially scans each signal and stores the measured amount.
6 to the computer 13. The image from the television camera is displayed on a monitor television 17. Furthermore, the multi-joint arm movement mechanism 7
The amount of movement is calculated by the computer 13 based on the output signal of the encoder 18. The distance measuring device 16 is a device that uses ultrasonic waves.
The side rangefinders 5 ₁ to 5 ₈ are shown in Fig. 4 at A in Fig. 2.
As shown in the -A cross section, eight ultrasonic elements 19 ₁ to 19 ₈ are fixed at equal intervals around the most advanced arm 1 ₁ . These ultrasonic elements 19 ₁ to 19 ₈ are
For example, four pairs of elements 19 ₁ and 19 ₅ are fixed facing outward in a direction perpendicular to the axis of arm 1 ₁ , and an obstacle 2 shown by diagonal lines is fixed.
0, that is, to obtain a polygonal approximation such as that formed by points A ₁ to _{A 8} . The distance measuring device 16 is composed of a circuit as shown in FIG. This circuit consists of ultrasonic element 19 ₁
~ ₁₉₉ (including element ₁₉₉ installed in front of the arm)
The pulse oscillators 21 ₁ to 21 ₉ generate pulses at predetermined intervals, respectively, and the pulse oscillators generate ultrasonic pulses from the element, and the generated ultrasonic pulses are reflected by the obstacle 20 and generate pulses. The receivers 22 ₁ to 22 ₉ receive the signals, and the scan control circuit ₂₃ controls the operation order _of these pulse oscillators and receivers. a counter 24 that stops at the output signal and measures the time during this time;
A register 25 that stores the data of this counter 24 and sequentially takes out the contents of the counter 24 and resets it, a clock oscillator 26 that is connected to the counter 24 and outputs a signal of a constant period, and a clock signal of this clock oscillator 26. It mainly consists of a dividing period 27 that converts the signal into a signal with a predetermined period necessary to sequentially operate the ultrasonic elements.
Note that the register 25 is configured to be controlled by a signal from the scan control circuit 23, and outputs measured data from each of the elements 19 ₁ to 19 ₉ serially from an output 28 . This output 28 is input to the computer 13 and performs calculations to be described later. FIG. 6 is a diagram illustrating a procedure for guiding the tip of the multi-joint arm shown in FIG. 2 to point Q of the inspection target shown in FIG. 1 in the control flow of FIG. 5. Table 1 shows each control cycle and the positions of the multi-joint arm tips and joints at that time.

【table】

[Table] The control of the apparatus of the present invention will be explained in detail below with reference to FIGS. 6, 7, and Table 1. The driver first guides the tip of the arm to the P ₀ point. Assuming that the manual operation mode is selected at this time, the position can be easily determined by viewing the image from the television camera 3 at the tip and the obstacle profile on the side of the arm. Once the tip is positioned at P ₀ , it enters automatic operation mode. To make the explanation easier to understand, it is assumed that all the unit arm lengths l of the multi-jointed arms are equal, and that they move forward or backward by the unit arm length in one control cycle. At point P ₀ , there is no obstacle in front of the arm tip.
Since the tip is at the center of the side obstacle profile, it moves forward by l and advances to point P _1. At this time, 2 ₁ comes to point P ₀ as shown in Table 1. At point _P1 , the conditions are the same as at point _P0 , so the tip moves forward by l again and the tip reaches _P'2 . At this time
2 ₁ comes to P ₁ and 2 ₂ comes to P ₀ . At point P′ ₂ , the arm tip is not located at the center of the side obstacle profile, so the control is performed to correct this and the tip is corrected to P ₂ . Then move it forward by l in that direction. By repeating the above control cycle, the television camera at the end of the arm can be moved to a location where the Q point can be easily inspected. As is clear from Table 1, the joints 2 ₁ to 2n are P ₀ , P ₁ , P ₂ ,...
...The control is extremely easy because the control is performed so that the point passed by the joint one ahead in the order of P _i is faithfully passed through with a delay of one control cycle. Front distance Xf
The limit value of can be selected to be a little longer than l, but it may be better to consider the focal length of the lens of the television camera 3, and it is necessary to make it possible to set it from the outside. The limit value of the minimum lateral distance Min [Xi] also needs to take into account the thickness of the arm, _l1 , the size of the space that it must pass through, etc., so it is desirable to be able to set it from the outside. . In reality, human judgment is required to advance from P ₇ to P′ ₈ or swing from P′ ₁₁ to P ₁₁ , but the driver
Not only can the operator familiarize himself with the object to be inspected by looking at the design drawings in advance, but he can also work while constantly watching the image from the television camera 3 on the monitor television 17, so the burden on the driver can be kept to a minimum. When returning the multi-joint arm from point Q,
P ₁₁ , P ₁₀ , . . . P ₀ may be reversed so that each joint 2 ₁ to 2n faithfully passes through the point that the one rear joint has passed, with a delay of one control cycle. In addition, in order to facilitate understanding of the content of the invention, 2.
The explanation was given using an example of a multi-joint arm that moves within a dimensional plane, but if a multi-joint arm with two degrees of freedom per joint is used, it is possible to construct a remote control device that can freely move around in a three-dimensional space. . In addition, we used an example of an inspection device with a TV camera attached to the end of the multi-jointed arm, but if the end is equipped with a torque wrench, magnetic chuck, etc., it can be used to tighten nuts, collect loose parts, etc. Work is also possible. Next, the distance measuring device is not limited to the above-mentioned ultrasonic type, but may be one that measures distance optically. In particular, we used an ultrasonic type distance meter attached to the tip of the arm, but for example, to measure the distance to an obstacle in front of the camera, we installed two cameras at the tip and emitted a light beam forward to create a light beam. A spot on the obstacle may be imaged by two cameras, and the distance to the obstacle may be automatically measured from the parallax of each image.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an object to be inspected to explain the outline of the present invention, FIG. 2 is a partially omitted perspective view of the apparatus of the present invention, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. 4
The figure is a cross-sectional view taken from the A-A plane in Figure 2.
6 is a flowchart of control of the apparatus of the present invention, and FIG. 7 is an explanatory diagram to help understand FIG. 6. 1... Multi-joint arm, 2... Joint, 3... Imaging device, 4... Front rangefinder, 5... Side rangefinder, 9
...Control circuit, 12...Motor drive circuit, 13...
...Computer, 14...Computer input/output device, 16...
Distance measuring device.

Claims (1)

[Scope of Claims] 1. A multi-joint arm formed by connecting a plurality of arms via joints; a moving means for moving the entire multi-joint arm; and a moving means provided at the tip of the multi-joint arm. a distance measuring device consisting of a signal generating element and a signal receiving element for measuring the distance to obstacles around the object; and an arm for avoiding contact with the obstacle based on the distance information obtained by the distance measuring device. Control to operate the multi-joint arm by generating a movement target point of the tip and controlling the joint angle of the joint part and the movement amount by the moving means so that the movement target point becomes the movement target point of the joint part. An articulated arm control device comprising: means; 2. The multi-joint arm control device according to claim 1, wherein the distance measuring means is provided on the most advanced arm. 3. Claim 1, characterized in that the distance measuring means comprises means for measuring the distance to an obstacle in front and means for measuring the distance to an obstacle on the side. The articulated arm control device described. 4. The multi-joint arm control device according to claim 1, wherein the distance measuring means measures distance using ultrasonic waves. 5. The multi-joint arm control device according to claim 1, wherein the most advanced arm is provided with an imaging device. 6. The multi-joint arm control device according to claim 5, wherein the leading edge of the imaging device is arranged within a measurement limit value of the distance measuring means. 7. The multi-joint arm control device according to claim 1, wherein the distance measuring means comprises two imaging devices.