A method and system for controlling a travelling body so as to move forward along a predetermined route

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present inevention relates to a method and system for controlling a travelling body so as to move forward along the predetermined route of the movement of travelling body.

(2) Description of the Prior Art

As a travelling body which should be moved forward along the predetermined route of the movement of travelling body while a given work is performed, there are given a shield for driving a tunnel, or for laying a water supply pipe or a sewage pipe, an unmanned vehicles or the like, for example.

The aforementioned shield, unmanned vehicles or the like is generally comprised of a body and a steering means for controlling the direction of movement of the body so as to move forward along the predetermined route.

Particularly, when laying various pipes in the ground by using a shield, the shield encounters varying intensity of the resistance of soil due to a change in the nature of soil, the presence of groundwater, etc.

Because of this, according to circumstances, even if a shield is driven by uniform power, the shield is moved in the direction of less resistance off the predetermined route. In such a case, an operator measures with the eye the quantity and direction of deviation of the shield from the predetermined route resulting from the movement of shield in the ground, and makes the needed correction in the direction of shield by controlling the steering means according to the quantity and direction of deviation of the shield from the predetermined route.

Now, the steering means of the shield is concretely explained.

For example, the shield developed by the present applicant and described in Japanese Patent Laying-open No. 57-205698 is comprised of a tail part and a head part positioned on the front end of the tail part which are connected with each other. A graduated plate is fixedly mounted on the fixed location of the aforementioned tail part. A pointer is arranged on the head part, which pointer faces the graduated plates, and can move according as the head part deflects from the tail part. An image of the aforementioned graduated plate is monitored by a TV-camera and shown on a display of a monitor TV.

Further, visible ray having such a straight travelling property as that of laser beam, etc., as the reference ray is sent along the predetermined route ( a direction of excavation or a pipe-laying direction ). This visible ray is projected on the graduated plate, while an operator measures with the eye the first position of visible ray on the graduated plate when starting the excavation, and besides the operator measures with the eye a difference between the first position of visible ray when starting the excavation and the second position of visible ray after moving forward the shield through some length and a change in the direction of shield, and adjusts the travelling direction of shield by driving the jacks according to the measured difference between the first position of visible ray when starting the excavation and the second position of visible ray after moving forward the shield through some length.

As above-mentioned, the operation of the shield is largely dependent on the experience and perception of operator, and therefore an operator is required to have high skill. Accordingly, a shield which can be readily operated is required. There are U.S.P. 4,875,184, U.S.P. 4,809,175 and U.S.P. 4,873,725 as the Prior Art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method for automatically controlling a travelling body such as a shield which should be moved forward along the predetermined route while a given work is performed.

An another object of the present invention is to provide a system for automatically controlling a travelling body such as a shield which should be moved forward along the predetermined route while a given work is performed.

The first object is accomplished by a method for controlling a travelling body provided with a body and a steering means along the predetermined route comprising the steps of:

• measuring a distance between the body and the predetermined route and a direction of deviation of the body from the predetermined route;
• inputting as an observed value the above measured distance between the body and the predetermined route into an antecedent operation part in which the membership functions corresponding to distances between the body and the predetermined route are prestored, and performing an operation of grade at the antecedent based on the the above measured distance between the body and the predetermined route;
• inputting the obtained grade into a consequent operation part in which the membership functions corresponding to manipulated values are prestored, and performing an operation of a manipulated value at the consequent based on the grade outputted from the antecedent operation part; and
• outputting the obtained manipulated value into the steering means, said steering means being controlled according to the manipulated value.

According to the present invention, when the travelling body has deviated from the predetermined route with the progress of the travelling body, the travelling body can be controlled along the predetermined route by measuring the quantity and direction of deviation of the travelling body from the predetermined route, performing an operation of the manipulated value based on the measured quantity of deviation of the travelling body from the predetermined route, controlling the steering means according to the manipulated value and the direction of deviation.

That is to say, an operation of effective degree based on the observed value at the antecedent operation part can be performed by predetermining the membership functions in the antecedent operation part according to data corresponding to quantities of deviation of the travelling body from the predetermined route and utilizing accumulated data of know-how of steering technique of a number of veteran operators, predetermining the membership functions at the consequent operation part according to data corresponding to maniputated values based on the quantities of deviation of the travelling body from the predetermined route, measuring a quantity of deviation of the travelling body from the predetermined route resulting from the progress of the travelling body, and inputting as an observed value the measured quantity of deviation of the travelling body from the predetermined route into the antecedent operation part. Then, an operation of manipulated value based on the observed value, namely the quantity of deviation of the travelling body from the predetermined route can be performed by reducing the membership functions at the consequent according to the grade , and combining the reduced membership functions. The manipulated value expresses the value based on know-how of a number of operators, which is recognized as the most valid manipulated value. Accordingly, the travelling body can be controlled along the predetermined route by driving the steering means based on the manipulated value outputted from the consequent operation part into the steering means.

Further, the first object of the present invention is also accomplished by a method for controlling a travelling body provided with a body and a steering means along the predetermined route comprising the steps of:

• measuring a distance between the body and the predetermined route and a direction of deviation of the body from the predetermined route, as well as the quantity and direction of displacement of the steering means relative to the body ;
• inputting as an observed value the above measured distance between the body and the predetermined route into an antecedent operation part in which the membership functions corresponding to distances between the body and the predetermined route are prestored, and performing an operation of grade at the antecedent;
• inputting the obtained grade into a consequent operation part in which the membership functions corresponding to manipulated values are prestored, performing an operation of manipulated value at the consequent part, comparing the obtained manipulated value with the quantity of displacement of the steering means relative to the body, and outputting as a controlled value a value corresponding to the difference between the manipulated value and the quantity of displacement of the steering means relative to the body, said steering means being controlled according to the controlled value.

According to the second method above-mentioned, the manipulated value can be obtained based on the quantity of deviation of the travelling body from the predetermined route by measuring the quantity and direction of deviation of the travelling body from the predetermined route and the quantity and direction of displacement of the steering means relative to the body(the quantity and direction of steering ), inputting the quantity of deviation of the travelling body from the predetermined route into the antecedent operation part in the same manner as the first method, performing an operation of the grade , and inputting the obtained grade into the consequent operation part. Then, the travelling body can be controlled by a controlled value based on the quantity of deviation of the travelling body from the predetermined route and the quantity of steering at present, by comparing the manipulated value outputted from the consequent operation part with the quantity of displacement of the steering means relative to the body, inputting as the controlled value a difference between the former and the latter, and driving the steering means according to the controlled value.

The second object of the present invention is accomplished by a control system for controlling a travelling body along the predetermined route comprising a travelling body having a body and a steering means, an optical pointer indicating the displacement of the steering means relative to the body, a visible light arranged along the predetermined route, an indicator arranged within the body on which the optical pointer and the visible light are projected, a color image pickup means arranged facing the indicator, a color image receiving means for displaying image monitored by the color pickup means, an image processing means connected with the color receiving means and in which an operation of coordinates of the optical pointer and visible light projected on the indicator is perfomed, a fuzzy operation means in which the manipulated value is calculated based on the membership functions at the antecedent and the consequent predetermined corresponding to values of coordinates of visible light calculated by the image processing means, a comparator means for comparing the manipulated value calculated by the fuzzy operation means with the coordinate values of optical pointer caluclated by the image processing means and outputting as a controlled value the difference between the former and the latter, and a driving means for driving the steering means according to the controlled value outputted from the comparator into the driving means.

In the above-mentioned system, it is preferable that the optical pointer and the visible light have colors varying with each other. Further. it is preferable that the fuzzy operation means is comprised of an antecedent operation part for prestoring the membership functions corresponding to the distances between the origin of coordinates and the visible light, performing an operation of grade based on input data of the distance between the origin of coordinates and the visible light, and outputting the grade, and a consequent operation part for prestoring the membership functions corresponding to the manipulated value, performing an operation of a manipulated values based on the grade outputted from the antecedent operation part, and outputting the manipulated value, wherein in the consequent operation part the membership functions corresponding to the manipulated values are given into triangles, respectively, the triangles are reduced according to the grade inputted, respectively, moments of rotation are obtained from the products of areas of the reduced triangles and positions of the center of gravity thereof, respectively, the obtained moments of rotation are summed up, and the sum total of the moments of rotation is divided by the sum total of areas of the reduced triangles by which the controlled value is obtained, which controlled value is outputted from the fuzzy operation means.

In the above-mentioned system, data corresponding to quantities of deviation of the body from the predetermined route are prestored as antecedent membership functions in the antecedent operation part, data of manipulated values corresponding to quantities of deviation of the body from the predetermined route as know-how of operator are prestored as consequent membership functions in the consequent operation part, a quantity and direction of the body from the predetermined route are measured, and the above-mentioned data corresponding to the quantity of deviation of body from the predetermined route is inputted into the fuzzy operation means, by which at the antecedent operation part, the grade of the membership function based on data inputted at the antecedent operation part can be calculated and the grade can be outputted into the consequent operation part. Then, the operations concerning reducing the membership functions and the center of gravity of the combined reduced membership functions based on the grade at the consequent operation part can be perfomed, and the result can be outputted as the manipulated value.

Further, the travelling body can be always moved forward along the predetermined route by determining a quantity and direction of steering at the measuring point by measuring the quantity and direction of displacement of the steering means relative to the body , comparing the steered value with the manipulated value, driving the steering means by using the difference of the former and the latter as the controlled value.

In the above-mentioned control system, the distance and direction of deviation of the body from the predetermined route and the quantity and direction of the steering means relative to the body can be measured by disposing the indicator in the body, arranging visible light along the predetermined route and providing optical pointer displaying the displacement of the steering means in the body, projecting the visible light and the optical pointer.

That is to say, laser spot can be formed on the indicator disposed on a plane intersecting with the predetermined route by projecting laser beam as visible light on the indicator. In this case, when a spot origin is set at a position of the laser spot on the indicator at the starting point of the travelling body and the laser spot is moved away from the spot origin, the quantity of moving away of the laser beam from the spot origin on the indicator corresponds to the quantity of deviation of the travelling body from the predetermined route, and the direction of moving away of the laser beam from the spot origin on the indicator corresponds to the direction of deviation of the travelling body from the predetermined route.

Further, the quantity of displacement and direction of the steering means relative to the body can be measured by projecting the displacement of the steering means relative to the body on the indicator by means of optical pointer.

That is to say, if a pointer origin is set at a position of optical pointer relative to the indicator when the steering means is put at a neutral position relative to the body, the optical pointer travels on the indicator with the displacement of the steering means relative to the body. Therefore, the present quantity and direction of steering can be measured by measuring the quantity and direction of deviation of the optical pointer relative to the pointer origin.

Therefore, the quantity and direction of moving away of the laser spot from the spot origin can be expressed by the coordinates, and the quantity and direction of deviation of the optical pointer from the pointer origin can be expressed by monitoring the indicator by the color image pickup means while the travelling body is moved forward, and processing the image of the indicator by the image processing means connected through the color image receiving means with the color image pickup means. The indications of the laser spot and the optical pointer in the coordinates can be expressed in the X-Y rectangular coordinates wherein the quantity and direction of moving away of the laser spot relative to the spot origin and the quantity and direction of deviation of the optical pointer from the pointer origin can be expressed by the X coordinates directed horizontally on the indicator and the Y coordinates directed vertically on the indicator, concerning travelling body such as shield.

Further, the grade of the membership function stored at the antecedent can be calculated by inputting the quantity of moving away of the laser spot from the spot origin into the antecedent operation part in the fuzzy operation means, performing the operation of reducing of the membership function stored at the consequent based on the grade inputted and the operation of position of the center of gravity of the combined reduced membership functions at the consequent operation part, and outputting the result as the manipulated value.

The manipulated value is a value based on the quantity of moving away of the laser spot from the spot origin, and does not include the present steered quantity. Therefore, by comparing the quantity of deviation of the optical pointer from the pointer origin with the maniputated value outputted from the fuzzy operation means at the comparator, the difference between the former and the latter can be outputted. Then the travelling body can be controlled along the predetermined route by driving the driving means complying with the controlled value.

Further, the optical pointer having a color different from the color of the visible light facilitates the operation of image processsing at the image processing means.

Further, the fuzzy operation means is comprised of the antecedent operation part in which the membership functions corresponding to distances between the origin and the visible light are prestored, and a given operation of grade is performed based on input data on a distance between the origin and the visible light and the grade corresponding to the distance between the origin, and from which the visible light is outputted from the antecedent operation part, and a consequent operation part in which the membership functions corresponding to the manipulated value are prestored, and a given operation of manipulated value is perfomed based on the grade outputted from the antecedent operation part, wherein the membership functions corresponding to the manipulated value are given in the form of triangles, respectively, the triangles are reduced according to the inputted grade, moments of rotation are obtained from products of areas of the reduced triangles by positions of the centers of gravity thereof and these moments of rotation are summed up, and manipulated value is obtained by dividing the sum total of the moments of rotation by the sum total of areas of the reduced triangles, and the obtained manipulated value is outputted from the consequent operation part. With the above mentioned simple fuzzy operation means, an operation of manipulated value (defuzzication) can be performed in a short time.

Namely, lengths of the bases of several triangles and the position of the centers of gravity thereof projected on the base thereof can be determined uniformly by defining the membership functions of fuzzy set in the form of triangles and aligning these triangles on the axis of abscissa according to the control rule. Therefore, lengths of the base of the reduced triangles and positions of the centers of gravity thereof porjected on the axis of abscissa are not changed even if the consequent membership functions expressed in the form of the triangles are reduced by degrees outputted from the antecedent. Further, areas of the reduced triangles can be easily calculated by lengths of the bases of original triangles and the grade.

Therefore, operation of a position of the center of gravity of the combined reduced triangles can be performed by obtaining moments of rotation from product of the areas of the several triangles, summing up these moments of rotation and dividing the sum total of the moments of rotation by the sum total of the areas of reduced triangles. The value of the above-mentioned position of the center of gravity can be outputted as the manipulated value from the consequent operation part.

By means of the above mentioned system of controlling a travelling body so as to move forward along the predetermined route where in know-how of steering of the travelling body which is attained by a plurality of operators of experience is accumulated, an operator can automatically control the travelling body so as to move forward along the predetermined route so that the operator can be easily control the travelling body without the help of a veteran operator when the travelling body is moved forward along the predetermined route.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing:

• Fig. 1 is a schematic illustration of a shield;
• Fig. 2 is a block diagram of a control system for controlling the shield:
• Fig. 3 is a block diagram of a circuit by which a visible or optical pointer data is fetched from an image receiving device;
• Fig. 4 is a representation of an indicator taken from the backside;
• Figs. 5(a) to (c) are views of a shield which is moved off a predetermined route with a forward movement of the shield, respectively;
• Fig. 6 is a graphical representation showing the antecedent membership functions when the shield is controlled;
• Fig. 7 is a graphical representation showing the consequent membership functions corresponding to the antecedent membership functions;
• Figs. 8(a) to (d) are graphical representations showing the positions of the centers of gravity of triangles of the consequent membership functions; and
• Fig. 9 is a graphical representation showing the reduced consequent membership function wherein the triangles of consequent membership functions are reduced by the grade, together with the consequent membership functions which are not reduced by the grade shown by the dotted line.

DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENT

Then, a method and system for the control of a shield wherein the aforementioned method and system for controlling a travelling body so as to move forward along the predetermined route of the movement of travelling body are applied for the control of a shield as a travelling body are illustrated by way of example.

A method and system for controlling a travelling body according to the present invention concern a method and system for moving forward a travelling body, for example a shield A along the predetermined route in the ground for laying a water supply pipe or a sewer pipe in the ground by measuring a a quantity and direction of deviation of the shield A from the predetermined route, which are caused by a change in the ground resitance and others, and making the needed correction in the direction of the shield A according to the measured quantity and direction of deviation of the shield A from the predetermined route.

Referring now to Fig. 5 (a), first, a shield A is positioned in a pit formed at the starting point of laying out a pipeline B. Then the shield A is pushed from the right of Fig. 5 (hereinafter referred to as "the rear") toward the left of Fig. 5 (hereinafter referred to as "the front") along the predetermined route, wherein if there is a change in the ground resitance in the front, the shield A deviates from laser beam 10b travelling along the predetermined route as shown in Fig. 5(b), in spite of the shield A being pushed forward with a fixed power. At this time, according to the present invention, an indicator 7 mounted in a body 1 of shield A is monitored by a television camera 8, the quantity and direction of deviation of the shield A from the spot origin ₀₁ of laser spot 10 are measured by processing the image of the indicator 7, and the shield A is controlled so as to be moved forward along the leser beam 10b by adjusting a head 2 of shield A relative to the body 1 by controlling jacks 3 and 4 according to the quantity and the direction of deviation of the shield A from the predetermined route as shown in Fig. 5(c).

Referring to Fig. 1, an outline of the structure of the shield A and its accessories is given.

A shield A shown in Fig. 1 is used when laying pipes such as water pipes or sewer pipes, etc. in the ground. The shield A has the same structure as that of a shield disclosed in Japanese Patent Laying-open 57-205698. The shield A excavates earth and sand by revoluting a cutter head C provided in the front of the shield A. Exavated earth and sand are discharged out by a pump mounted in the shield A, while the shield A is pushed forward by pipe jacking device D mounted in the rear of the shield A, and pipes are laid with being joined with each other in the ground by which the desired pipeline B is constructed in the ground.

The shield A comprises a body 1 provided with meters, pumps, etc. not shown in the figure, and a head 2 including a steering means for controlling a travelling direction of the body 1 to the predetermined route, said head being provided in the front of the body 1. The body 1 is connected with the head 2 through two jacks 3 and 4 and a rod 5 positioned at equal spaces on the circumference of a circle having the center identical with the axial center of shield A. The jacks 3 and 4, and the rod 5 are provided with universal joints 3a, 4a, and 5a, at ends of the joints 3 and 4 and the rod 5, respectively, and attached to both the body 1 and the head 2 through the universal joints 3a, 4a, and 5a. Thereby, the head 2 can turn around the joint 5a of rod 5 to a direction different from a direction of the body 1 by the desired angle.

In the present embodiment, hydraulic cylinders are used as the jacks 3 and 4. The jacks 3 and 4 are connected with a driving device 6 comprised of a hydraulic unit provided in the body 1, a flow control unit for controlling a flow rate of pressure oil and others.

An indicator 7 is provided at the fixed position of the body 1, and a television camera 8 as means for monitoring the indicator 7 is arranged facing the indicator 7. Laser beam 10b which defines both an image of the under-mentioned optical pointer 9 and the predetermined route is projected on the indicator 7. The indicator 7 is monitored by the television camera 8 and besides the monitored image is processed by image processing unit 22 by which the quantity and direction of deviation of the body 1 from the laser beam 10b, the quantity and direction of displacement of the head 2 relative to the body 1 can be detected.

A bar 9a reaching the indicator 7 is secured at the fixed position of the head 2. An optical pointer 9 is provided at an end of the bar 9a which is identical with the axial center of shield A so as to be positioned in the rear of the indicator 7. The optical pointer 9 is displaced on the surface of indicator 7 together with the diplacement of the head 2 relative to the body 1. As the optical pointer 9, use can he made of an optical pointer of cross pattern, for example and also of light emitting element as LED and others.

In the present embodiment, LED emitting green (G) is used as optical pointer 9.

A laser oscillator 10a such as a laser transit is arranged in the rear of shield A, from which the laser beam 10b travelling along the predetermined route is emitted toward the indicator 7. The laser beam 10a is travelled in alignment or parallel with the axis of pipe B. The laser beam 10b which is projected on the indicator 7 forms a laser spot 10 on the indicator 7.

In the present embodimenet, use is made of He-Ne laser emitting red color (R) laser beam.

Therefore, as shown in Fig. 4, a red color laser spot 10 is formed on the indicator 7 by projecting the laser beam 10b on the indicator 7. This laser beam 10a is not necessarily required to be in alignment with the indicator 7. The position of laser spot 10 at the time when the shield A is started is stored as a spot origin ₀₁, and thereafter the quantity and direction of the body 1 from the laser beam 10b can be measured by measuring the distance between a laser spot 10 and the spot origin ₀₁ and the direction of deviation of the laser spot from the spot origin in the forward movement of the shield A. When the head 2 is in a neutral position relative to the body 1, LED 9 arranged on a side of the indicator 7 facing the television camera 8 is positioned to be in alignment with the axis of shield A, wherein a position of the LED 9 in starting the shield A is pointer origin 0₂.

In the figure, E designates a control panel provided with a control unit for controlling the shield A, the pipe jacking device D and others, an image receiving unit for monitor and others.

Then, referring to Figs. 2 and 3, the structure of a control system for controlling the above-mentioned shield A is explained.

As shown in Figs. 2 and 3, the television camera 8 is connected with an image receiving unit 21. As shown in Fig. 3, the image receiving unit 21 is comprised of a image receiving part 21 a and a color-separating part 21b. The receiving part 21 a has the same structure as that of a conventional television image receiving unit, which has functions of a screen for monitor display, which shows a picture of the indicator 7 taken by the television camera 8. The color-separating part 21 b has functions required for separating a signal of the color G of LED 9 and a signal of the color R of laser spot 10 from a picture of the indicator 7 taken by the television camera 8 and sending these signals to the image processing unit 22.

That is to say, in the image receiving unit 21, a signal of the color R corresponding to laser spot 10 can be separated from the picture of indicator 7 taken by the television camera 8 and this signal can be sent to the image processing unit 22 by inputting both an output signal from R matrix part of the image receiving part 21 a and a signal of synchronizing separation part in to R+syncronizing part by which the R signal is synchronized to a picture signal while amplifying the R signal in an output impedance adjusting part. Further, the G signal of LED 9 is also separated from the picture of indicator 7, and sent to the image processing unit 22 through a wire 23b.

The image processing unit 22, which comprises a conventional image processing unit, is used for calculating coordinate value of the G signal and the R signal tarnsmitted from the image receiving unit 21,

The image processing unit 22 is connected with an image processing control unit 24 having a memory part, a control part and others. The image processing unit stores data of the spot origin ₀₁ and the pointer origin ₀₂ shown in Figs. 4 and 5 drawn from a picture of the indicator 7 of shield A in starting the shield A, and coordinate data of the transmitted R signal relative to the spot origin ₀₁ are outputted into a fuzzy operation unit, and besides coordinate data of the transmitted G signal relative to the pointer origin ₀₂ is outputted into comparator 26.

Therefore, to calculate coordinate value of the R signal relative to the spot origin ₀₁ at the image processing unit 22 makes possible measurements of a distance between the body 1 and the laser beam 10b and the direction of deviation of the body 1 from the laser beam 10b, and to calculate coordinate value of the G signal relative to the pointer origin ₀₂ makes possible measurements of the quantity and direction of displacement of LED 9 relative to the body 1, that is, the quantity and direction of displacement of the head 2 relative to the body 1.

In the present embodiment, the image hold signal is transmitted at fixed intervals from the image processing control unit 24 to the image processing control unit 22, by which the image information in the timing is held at the image processing unit 22. In the above-mentioned image, coordinate values of the laser spot 10 is calculated on a X-Y rectangular-coordinate system in which the origin is spot origin ₀₁, X is the abcissa, and Y is the ordinate, and with data on the X-coordinate of the laser spot 10 being outputted into the fuzzy operation unit 25, data on the X-coordinate of the LED 9 is outputted into the comparator 26. Further, in the fixed time after data on the X-coordinates of both laser the spot 10 and the LED 9 are outputted, data on the Y-coordinate of laser spot 10 is outputted into the fuzzy operation unit 25, while data on the Y-coordinate of the LED 9 is outputted into the comparator 26.

Data on the X and Y-coordinates of both the laser spot 10 and the LED 9 are thus outputted in order into the fuzzy opeartion unit 25 and the comparator 26, by which manipulated value according to the horizontal deviation (X) and vertical deviation (Y) can be operated in order.

The fuzzy operation unit 25 is comprised of an antecedent operation unit 25a, an antecedent membership function memory part 25b, a consequent operation part 25c, a consequent membership function memory part 25d and others, wherein grade is calcualted from the corresponding membership function using as observed values data on the coordinate of the R signal transmitted from the image processing unit 22, and outputted into the consequent operation part, and in the consequent operation part, the reduction of membership function complying with the antecedent membership function and the position of center of gravity of the reduced membership function are calculated and a value corresponding to the position of center of gravity is outputted as manipulated value from the fuzzy operation unit 25.

There will be later explained the operational method by the above-mentioned fuzzy operation unit 25.

The signal of manipulated value outputted from the fuzzy operation unit 25 is transmitted to the comparator 26, in which the optimum controlled values are calculated by comparing the manipulated value corresponding to the quantity of deviation of the body 1 from laser beam 10b with the quantity of correction in direction (manipulated value ) given at present to the body 1 and from which the optimum controlled values are outputted.

An interface 27 changes the signal outputted from the comparator 26 as controlled values into the signal for controlling the quantities of the opening and closing of valve to a control unit for controlling flow rate of hydraulic oil at the driving device 6, by which the amount of pressure oil supplied to the jacks 3 and 4 so that the head 2 is displaced relatively to the body 1 according to the controlled values inputted from the comparator 26.

Then, a concrete explanation is given about the inferential operation of the quantities of control at the fuzzy operation unit 25 when the shield A is operated in the horizontal direction.

The membership functions shown in Fig. 6 are stored at the antecedent membership function memory part 25b, in which the membership functions concerns the quantities of horizontal deviations of the body 1 from laser beam 10b. Therefore, the membership functions corresponding to the quantities vertical deviations of the body 1 from laser beam 10b is also stored at the antecedent membership function memory part 25b.

Hereinafter, the inferential method about the quantities of control corresponding to horizontal deviations is explained. However, the inference of the controlled values to the quantities of vertical deviations of the body 1 from laser beam 10b can be carried out in the same way.

The membership function shown in Fig. 6 shows degrees of whether, when an operator observes the actual deviation of the laser spot 10 from the spot origin ₀₁ from the screen of the image receiving unit 21, he has a feeling that this deviation is large, or he has a feeling that this deviation is medium, or he has a feeling that this deviation is small.

The membership function shown in the figure and the membership function in the consequent part is set based on the accumulation of know-how of many operators.

For example, when laser spot 10 deviates from the spot origin 0, to the left by 7mm, it is shown that there exist an operator who has a feeling that the deviation of laser spot 10 from the spot origin ₀₁ is small and an operator who has a feeling that the deviation is medium. Degree that an operator has a feeling that the deviation is small and degree that an operator has a feeling that the deviation is medium are grade, respectively.

The quantity of deviation of the laser spot 10 from the spot origin ₀₁ is measured at the image processing unit 22. Data corresponding to the quantity of deviation of the laser spot from the spot origin is transmitted to the antecedent operation part 25a, in which the grade is calculated based on the memorized antecedent membership functions. In the operation, for example, when the quantity of deviation of the laser spot from the spot origin is 7mm and the direction of deviation is left, a value of the membership function at the point of 7mm on the left in Fig. 6 is calculated by which the grade is obtained, that is, from the figure, grade can be obtained as follows: the grade corresponding to a small deviation to the left

the grade corresponding to a medium deviation to the left

These grade α₁, and a₂ are outputted into the consequent operation part 25c.

The membership function shown in Fig. 7 is memorized at the consequent membership function memory part 25d. The membership function shows, when an operator observes actual deviation of laser spot 10 from the spot origin o₁ from the screen of the image receiving unit 21, a quantity of displacement with which the head 2 is displaced according to the actual deviation, that is a manipulated value, wherein respective triangles correspond to the antecedent membership functions shown in Fig. 6.

The direction of operation in Fig. 7 is in the reverse direction to observed direction of deviation.

As shown in the figure, when the consequent membership functions are expressed in triangles arranged in parallel on the X-coordinate, positions and shapes of these triagles are set uniquely.

Figs. 8(a) to (d) shows positions of the centers of gravity G₁-G₄ of four triangles B₁ -B₄ which compose righthand part of the consequent membership functions and lengths W₁ -W₄ of the bases of the triangles Bi - B₄.

As shown in the figure, heights of several triangles B₁ -B₄ are equal with each other and lengths W₁ -W₄ of the bases of several triangles B_i - B₄ are set uniquely. Therefore, positions of the centers of gravity G₁~G₄ of several triangles B₁~B₄ can be easily obtained by a conventional algebraic calculation.

Fig. 9 shows reduced triangles B₂' and B₃' in which B₂ and B₃ of the membership functions corresponding to grade α₁ and a₂ which are outputted from the antecedent operation part when the quantity of deviation of laser spot 10 from the spot origin o₁ are reduced by the grade α₁ and a₂.

As shown in the figure, the original triangle B₂ and the reduced triangle B₂' have the common base W₂, and the original triangle B₃ and the reduced triangle B₃ ' have the common base W₃, and besides the center of gravity G₂ of the triangles B₂ and B₂' and the center of gravity G₃ of the triangles B₃ and B₃ ' does not change.

Therefore, when positions of the centers of gravity of triangles B₂ and B₃ are G₂ and G₃, respectively, the center of gravity Y_o can be obtained from resultant moment obtained by calculating the moment of rotation having the weight corresponding to the areas of the reduced triangles B₂ ' and B₃ ' about the reduced triangles B₂' and B₃' as follows:

Then, if M₂ is equal to G₂ · W2 and M₃ is equal to Ga · W3,

The Yo value thus obtained indicates the position of the center of gravity of the combined triangle which is composed of the triangle B₂ ' and B₃' . Accordingly, the Yo value can be outputted as manipulated value from the consequent operation part 25c.

As above-mentioned, the following general formula for calculating manipulated value can be obtained:

Then, the method for controlling the shield A is explained referring to Figs. 5(a) to (c).

Fig. 5(a) shows the shield A at the starting position, at which the head 2 stands in the neutral position with respect to the body 1, and the position of LED 9 relative to the indicator 7 coincides with the axial center of the shield A. The indicator 7 is always monitored by the television camera 8, and the image of indicator 7 is processed at fixed intervals for measurement by the image processing unit 22. Then the position of LED 9 when starting the forward movement of the shield is stored as the pointer origin ₀₂ and the position of laser spot 10 at this time is stored as the spot origin o₁ at the iamge processing unit 24, respectively.

When the shield A deviates from the laser beam 10b as the predetermined route with the advance of the shield A as shown in Fig. 5(b), the laser spot 10 on the indicator 7 deviates from the spot origin o₁· Then, the position of the laser spot 10 is converted into X coordinate data and Y coordinate data on the X-Y coordinate system at the image processing unit 22, and the X coordinate data and the Y coordinate data are outputted into the fuzzy operation unit 25. At the image processing unit 22, the quantity of deviation of the LED 9 from the pointer origin ₀₂, and the direction of deviation of the LED 9 from the pointer origin ₀₂ are measured, and the quantity of deviation of the LED 9 from the pointer origin ₀₂ is converted into the X coordinate data and the Y coordinate data, which are outputted into the comparator 26. However, since in Fig. 5(b), the head 2 stands in the neutral position relative to the body 1, the X coordinate data and the Y coordinate data are outputted as 0 into the fuzzy operation unit.

When the measured quantity of deviation of the laser spot 10 from the spot origin 0, is 7mm and a direction of deviation thereof is on the left hand of the spot origin, the grade corresponding to the membership function of lefthand small deviation, a ₁ being equal to 0.75 and the grade corresponding to the membership function of the lefthand medium deviation, a ₂ being equal to 0.25 are outputted from the antecedent operation unit.

Then, the triangles B₂ and B₃ corresponding to the consequent membership function of righthand small deviation and the consequent membership function of righthand medium deviation, respectively, are reduced with the grade a being equal to 0.75 and the grade a ₂ being equal to 0.25, by which the reduced triangles B₂' and B₃' can be obtained as shown in Fig. 9.

From Fig. 8(b), the length W₂ of the base of triangle B₂ is equal to 30, the postion G₂ of the center of gravity thereof is equal to 13.3, M₂(= G₂xW₂) is equal to 400, and from Fig. 8(c), the length W₃ of the base of triangle B₃ is equal to 40, position G₃ of the center of gravity thereof is equal to 25.0, and M₃(=G₃xW₃) is equal to 1,000. Therefore, from the above M₂, α₁, M₃, and a₂,

From the above W₂, α₁, W₃ and a₂,

From the obtained values, the horizontal manipulated value can be obtained as follows: the horizontal manipulated value=500 32.5 = 16.9238(min.)

The manipulated value is transmitted from the fuzzy operation unit 25 into the comparator 26, at which the manipulated value is compared with horizontal coordinate data on deviation of LED 9. Since the quantity of deviation of LED from the pointer origin is equal to 0, the above manipulated value is sent as the controlled value through the interface 27 to the driving device 6, by which the hydraulic oil flow control unit in the driving device 6 is operated according to the manipulated value in such an extent that jacks 3 and 4 are operated by the given amount by which the head 2 is displaced to the left with respect to the body 1.

When the shield A further moves forward and reaches the position shown in Fig. 8(c), in the same manner as the above mentioned manner, the quantity and direction of deviation of laser spot 10 from the spot origin ₀₁ are measured, while the quantity and direction of deviation of the LED 9 from the pointer origin 0₂ are measured, and then the X coordinate data and the Y coordinate data of the laser spot 10 are outputted into the fuzzy operation unit 25, at which the manipulated value is calculated, and the manipulated value is outputted into the comparator 26, while the X coordinate data and the Y coordinate data about the LED 9 is outputted to the comparator 26. Then, at the comparator 26, these data are compared with each other, the difference between these data is sent as the controlled value through the interface 27 to the driving device 6.

The shield A can be driven along the laser beam as the predetermined route by carrying out at the fixed intervals the above mentioned operations.

In addition, when driving the shield A, it may be also possible to measure only the quantity and direction of deviation of the laser beam 10 from the spot origin ₀₁, input the coordinate data into the fuzzy operation unit 25, at which manipulated value is operated. In this case, a control of the shield is carried out in the open controlling method.