JP5797516B2 - Electric handy cart - Google Patents

Description

  The present invention relates to an electric handy cart.

  As an apparatus for assisting walking of a pedestrian who has weak legs and legs such as an elderly person, an electric handy cart shown in Patent Document 1 or Patent Document 2 has been proposed.

  The electric handy cart includes left and right drive wheels that can be driven to rotate independently by an electric motor, and an operating rod (cane portion) that a pedestrian grips. The operation rod is provided with an operation force detection device, and the operation force of the pedestrian acting on the operation rod is detected by the operation force detection device. The electric motor that drives the left and right drive wheels of the handy cart is driven based on the value of the pedestrian's operating force detected by the operating force detection device.

JP 2010-125221 A JP 2011-068239 A

  Here, in the above-described electric handy cart, it can be said that it is effective to provide a means for detecting an obstacle ahead of the cart that is the traveling direction of the cart as a safety function and automatically avoiding the obstacle. .

  Accordingly, the present invention has been made in view of the above-described circumstances, and provides an electric handy cart that can automatically avoid obstacles in front.

In order to solve the above-described problems, an electric handy cart of the present invention includes an operation rod that is held by a pedestrian, and an operation force detection device that is provided on the operation rod and detects an operation force applied to the operation rod by the pedestrian The first and second electric motors, first and second speed detecting means for detecting the rotation speeds of the first and second electric motors, respectively, and the first and second electric motors for rotational driving. An electric handy cart comprising: first and second drive wheels; and a control device that supplies a control current to the first and second electric motors based on a signal from the operating force detection device. An image detection device for detecting an image of an obstacle is provided. The control device includes target speed calculation means for calculating a target speed signal based on a force signal from the operation force detection device, and first and second speed detections. An averaging means for averaging the first and second detected speed signals from the stage and outputting an average speed signal, a deviation signal between the average speed signal from the averaging means and the target speed signal from the target speed calculation means A target current calculating means for calculating a target current signal to be supplied to the electric motor, and an obstacle image detecting means for converting the contour of the obstacle into a plurality of point position signals based on the image signal of the obstacle from the image detecting device. An obstacle image expansion means for forming a plurality of expansion circle signals corresponding to a plurality of expansion circles having a predetermined diameter centered on the plurality of point position signals, and a plurality of expansion circles based on the expansion circle signal A path acquisition means for calculating a path angle signal that is in contact with only one inflated circle and that is closest to the front direction line of the cart, and calculating a path angle signal that is an angle between the path tangent and the front direction line; Times based Avoidance signal output means for outputting an avoidance signal, first and second adjustment means for adjusting the target current signal by adjusting the avoidance signal, and outputting first and second adjustment current signals, and first and second First and second current output means for supplying first and second control currents to the first and second electric motors, respectively, corresponding to the first and second adjustment current signals from the two adjustment means. The obstacle image expansion means includes a plurality of first expansion circle signals corresponding to a plurality of first expansion circles having a first diameter with the plurality of point position signals as center positions, and a first expansion. A plurality of second expansion circle signals corresponding to a plurality of second expansion circles having a second diameter larger than the circle are formed, and the path acquisition means includes a plurality of the plurality of first expansion circle signals based on the plurality of first expansion circle signals. Front side while touching only one of the first expansion circles A first path tangent closest to the line is calculated, a first path angle signal that is an angle between the first path tangent and the front direction line is calculated, and further, based on a plurality of second expansion circle signals An angle between the second path tangent and the front direction line is calculated by calculating a second path tangent that is in contact with only one of the plurality of second expansion circles and is closest to the front direction line. The control device compares the first and second path angle signals, and if the difference angle between the first and second path angles is less than a predetermined angle When the second path angle signal is selected and the difference angle is equal to or larger than a predetermined angle, the second path angle signal is provided with path selection means for selecting the first path angle signal, and the avoidance signal output means is selected by the path selection means. Based on any one of the path angle signals selected from the first and second path angle signals. Outputting a signal, some motorized handy carts characterized.

  According to the electric handy cart of the present invention, an obstacle in front of the cart can be automatically avoided.

It is a perspective view which shows the electric handy cart of embodiment of this invention. It is a system block diagram of a control device of an embodiment of the present invention. It is a flowchart which shows the process performed with the control apparatus of embodiment of this invention. It is a figure which shows a mode that a path | route angle is detected by the control apparatus of embodiment of this invention.

(Embodiment of electric handy cart)
Next, an embodiment of the electric handy cart of the present invention will be described with reference to FIG. FIG. 1 is a perspective view of an electric handy cart according to the present embodiment.

  As shown in FIG. 1, the electric handy cart 1 includes a main body frame 2 formed of a pipe member, a rod-shaped operation rod 3 attached to an upper portion of the main body frame 2 and held by a pedestrian, and a main body frame 2. The case C, the first and second electric motors (4, 5) attached to both sides of the main body frame 2, and the first and second electric motors (4, 5) are respectively driven to rotate. And first and second drive wheels (6, 7). And in the case C, the control apparatus 10 and the battery 30 which supplies an electric current to an electric motor (4, 5) are provided. The handy cart 1 also includes first and second speed detecting means (4a, 5a) for detecting the rotational speeds of the electric motors (4, 5), respectively.

  A hand grip 8 is attached to the upper end of the operation rod 3, and a stereo camera 40 as an image detection device is provided in the hand grip 8, and an operation force detection device 9 is provided in the hand grip 8. Is provided. Here, the stereo camera 40 includes two CCD cameras (41, 42) arranged vertically in the vertical direction (axial direction of the operation rod), and detects an image of an obstacle in front of the handy cart 1. The operation force detection device 9 detects an operation force applied to the operation rod 3 by the pedestrian. Here, the operation force is a force by which the pedestrian pushes and pulls the handy cart 1 in the axial direction of the operation rod 3. A basket hook 60 that can suspend a shopping basket or the like is attached to the central portion of the operation rod 3.

(Control device)
Next, the control device 10 provided in the handy cart 1 will be described with reference to FIG. FIG. 2 is a system block diagram showing the control device 10 in the electric handy cart 1.

  The control device 10 includes a measurement unit 11, a target speed calculation unit 12, an image information acquisition unit 13 and an obstacle image conversion unit 14 as an obstacle image detection unit, an obstacle image expansion unit 15, and a route acquisition unit 16. A route selection means 17, an avoidance signal output means 18, a subtractor 19, a target current calculation means 20, an adder 21 as a first adjustment means, and a subtractor 22 as a second adjustment means. , First and second current output means (23, 24), an adder 25, and an averaging means 26.

The measuring means 11 samples the signal from the operating force detecting means 9 and outputs a force signal corresponding to this signal. The target speed calculation means 12 calculates a target speed signal (Vr) by integrating the force signal.

  The first and second detected speed signals (Va1, Va2) corresponding to the rotational speed of the electric motor (4, 5) detected by the first and second speed detecting means (4a, 5a) are added. The signal is added by the device 25 and averaged by the averaging means 26 and output as an average speed signal (Vave). Then, the average speed signal (Vave) is subtracted from the target speed signal (Vr) by the subtracter 19, and a deviation signal (Vε) between the target speed signal (Vr) and the average speed signal (Vave) is output from the subtractor 19. The

  Further, the target current calculation means 20 calculates a target current signal (i0) to be supplied to the electric motor (4, 5) based on the deviation signal (Vε) from the subtracter 19.

  Next, referring to FIG. 2, the electric motor (4, 5) provided in the electric handy cart 1 based on the obstacle image signal from the stereo camera (image detection device) 40 is controlled to avoid the obstacle. A means for supplying each of the currents (I1, I2) will be described.

  The image signal from the stereo camera 40 is referred to an image signal within a predetermined distance R0 (reference radius) from the camera 40 to the “provisional goal” (for example, within R0 = 5 m), and is processed as processing information in the control device 10. The control device 10 performs control for avoiding the obstacle based on the processing information.

  The image signal of the obstacle detected by the stereo camera 40 is converted into a point position signal of a plurality of rotating coordinate systems by the image information acquisition means 13, and the point position signal of this rotating coordinate system is converted into the obstacle position signal. The image conversion means 14 converts the signal into a point position signal in the XY coordinate system. In this way, the contour of the outer surface of the obstacle is detected as a plurality of point position signals. The point position signals are detected at equal pitches every angle “0.25 degrees” in the radial direction with the stereo camera 40 as the center.

  Then, a plurality of first, second, and third dilations of the first, second, and third diameters (L1, L2, L3) centered on the plurality of point position signals are performed by the obstacle image dilating means 15. A plurality of first, second and third expanded circle signals corresponding to the circle are formed. Here, the first diameter (L1) of the first expansion circle is set equal to the vehicle body width (L0) of the handy cart 1 (L1 = L0). Further, the second diameter (L2) of the second expansion circle is set to be longer than the first diameter (L1) of the first expansion circle by the length α1 (L2 = L1 + α1), and the third diameter The third diameter (L3) of the expansion circle is set longer by the length α2 than the first diameter (L1) of the first expansion circle (L3 = L1 + α2). Here, the length α2 is longer than the length α1 (α2> α1> 0), and is a first, second, and third expansion circle in order from a shorter diameter (L1 <L2 <L3). In the present embodiment, the first diameter (L1) is 60 cm (L1 = 60 cm), the second diameter (L2) is 80 cm (L2 = 80 cm), and the third diameter (L3) is 100 cm (L3 = 100 cm).

  Next, a “route angle signal” corresponding to an angle that is a direction in which the handy cart 1 should be advanced while avoiding an obstacle is calculated by the route acquisition unit 16 based on the plurality of first to third expansion circle signals. The

The path acquisition unit 16 is in contact with only one of the first expansion circles among the plurality of first expansion circles on a line extending radially from the camera 40 based on the plurality of first expansion circle signals and “front direction” A first route direction line closest to the “line” is calculated, and a first route angle signal (θ1) that is an angle between the first route direction line and the front direction line is calculated. Here, the “front direction line” refers to a virtual straight line extending from the cart 1 toward the “provisional goal” set in the front direction.

  Further, the path acquisition means 16 is in contact with only one second expansion circle among the plurality of second expansion circles on a line extending radially from the camera 40 based on the plurality of second and expansion circle signals. A second path direction line closest to the “front direction line” is calculated, and a second path angle signal (θ2) that is an angle between the second path direction line and the front direction line is calculated.

  Further, the path acquisition means 16 is in contact with only one third expansion circle among the plurality of third expansion circles on a line extending radially from the camera 40 based on the plurality of third and expansion circle signals. A third path direction line closest to the “front direction line” is calculated, and a third path angle signal (θ3) that is an angle between the third path direction line and the front direction line is calculated.

  Next, the route selection means 17 selects any one of the first to third route angle signals (θ1, θ2, θ3).

  In the route selecting means 17, first, the first route angle signal (θ1) and the third route angle signal (θ3) are compared, and the difference angle (| θ1) between the first and third route angles (θ1, θ3) is compared. When −θ3 |) is less than a predetermined angle (| θ1−θ3 | <φ1), the third path angle signal (θ3) is selected as the adjustment path angle (θ) (θ = θ3).

  If the difference angle (| θ1-θ3 |) between the first and third path angles (θ1, θ3) is equal to or greater than a predetermined angle (| θ1-θ3 | ≧ φ1), the first The path angle signal (θ1) and the second path angle signal (θ2) are compared, and the difference angle (| θ1-θ2 |) between the first and second path angles (θ1, θ2) is less than a predetermined angle (| When θ1−θ2 | <φ2), the second path angle signal (θ2) is selected as the adjustment path angle (θ9) (θ = θ2).

  When the difference angle (| θ1-θ2 |) between the first and second path angles (θ1, θ2) is equal to or greater than a predetermined angle (| θ1-θ3 | ≧ φ2), the adjustment path angle (θ) As a result, the first path angle signal (θ1) is selected (θ = θ1).

Next, the avoidance signal output means 18 selects any one of the path angle signals (θ1 or θ2 or) selected from the first to third path angle signals (θ1, θ2, θ3) by the path selection means 17.
An avoidance signal is output based on θ3). Here, the avoidance signal is a value obtained by multiplying the path angle signal (θ1, θ2, θ3) by the proportional gain (K), and each current supplied to the first and second electric motors (4, 5). The value is adjusted (δi = Kθ).

  Then, in the first and second adjustment means (21, 22), the target current signal (i0) is adjusted by the avoidance signal (δi) to be adjusted, and the first and second adjustment current signals (i1, i2) are adjusted. Are output from the first and second adjusting means (21, 22). Here, the first adjustment means 21 is an adder, and a signal obtained by adding the avoidance signal (δi) to the target current signal (i0) is output as the first adjustment current signal (i1) (i1 = i0 + δi). The second adjustment means 22 is a subtracter, and a signal obtained by subtracting the avoidance signal (δi) from the target current signal (i0) is output as the second adjustment current signal (i2) (i2 = i0). -Δi).

  Finally, the first and second adjustment current signals (i1, i2) from the first and second adjustment means (21, 22) by the first and second current output means (23, 24), respectively. Corresponding (proportional), the first and second control currents (I1, I2) are supplied to the first and second electric motors (4, 5), respectively.

(flowchart)
Next, an obstacle image information processing method processed by the control device 10 will be described based on the flowchart shown in FIG.

  When the electric handy cart 1 is activated (S1), the image signal of the obstacle detected by the stereo camera 40 is converted into point position signals of a plurality of rotational coordinate systems by the image information acquisition means 13 (S2). ), The point position signal of the rotating coordinate system is converted into the point position signal of the XY coordinate system by the obstacle image converting means 14 (S3).

  Then, a plurality of first, second, and third dilations of the first, second, and third diameters (L1, L2, L3) centered on the plurality of point position signals are performed by the obstacle image dilating means 15. A plurality of first, second and third expanded circle signals corresponding to the circle are formed (S4, S5, S6).

  Further, the path acquisition unit 16 is in contact with only one of the plurality of first expansion circles along a line extending radially from the camera 40 based on the plurality of first expansion circle signals. A first path direction line closest to the “front direction line” is calculated, and a first path angle signal (θ1) that is an angle between the first path direction line and the front direction line is calculated (S7).

  Similarly, the path acquisition unit 16 is in contact with only one second expansion circle among the plurality of second expansion circles on a line extending radially from the camera 40 based on the plurality of second and expansion circle signals. A second path direction line closest to the “front direction line” is calculated, and a second path angle signal (θ2) that is an angle between the second path direction line and the front direction line is calculated (S8). .

  Similarly, the path acquisition unit 16 applies only one third expansion circle among the plurality of third expansion circles in a line extending radially from the camera 40 based on the plurality of third and expansion circle signals. A third path direction line that is in contact with and closest to the “front direction line” is calculated, and a third path angle signal (θ3) that is an angle between the third path direction line and the front direction line is calculated ( S9).

  In the route selecting means 17, first, the first route angle signal (θ1) and the third route angle signal (θ3) are compared, and the difference angle (| θ1) between the first and third route angles (θ1, θ3) is compared. When −θ3 |) is less than a predetermined angle (| θ1−θ3 | <φ1), the third path angle signal (θ3) is selected as the adjustment path angle (θ) (θ = θ3) ( S10, S12).

  If the difference angle (| θ1-θ3 |) between the first and third path angles (θ1, θ3) is equal to or greater than a predetermined angle (| θ1-θ3 | ≧ φ1), the first The path angle signal (θ1) and the second path angle signal (θ2) are compared, and the difference angle (| θ1-θ2 |) between the first and second path angles (θ1, θ2) is less than a predetermined angle (| If θ1-θ2 | <φ2), the second path angle signal (θ2) is selected as the adjustment path angle (θ9) (θ = θ2) (S11, S13).

  When the difference angle (| θ1-θ2 |) between the first and second path angles (θ1, θ2) is equal to or greater than a predetermined angle (| θ1-θ3 | ≧ φ2), the adjustment path angle (θ) As a result, the first path angle signal (θ1) is selected (θ = θ1) (S11, S14).

Next, the avoidance signal output means 18 selects any one of the path angle signals (θ1 or θ2 or) selected from the first to third path angle signals (θ1, θ2, θ3) by the path selection means 17.
An avoidance signal is output based on θ3) (S15). Here, the avoidance signal is a value obtained by multiplying the path angle signal (θ1, θ2, θ3) by the proportional gain (K), and each current supplied to the first and second electric motors (4, 5). The value is adjusted (δi = Kθ).

(Specific example of path angle detection method)
Finally, a specific example in which the control device 10 of the electric handy cart 1 of the present embodiment detects the first to third path angles (θ1, θ2, θ3) will be described with reference to FIG.

  In the figure, three obstacles (X, Y, X) are scattered and arranged within the reference radius (R0), and image signals of these obstacles are sent to the control device 10 by the stereo camera 40. .

  These image signals detected by the stereo camera 40 are converted into point position signals of a plurality of rotating coordinate systems by the image information acquisition means 13, and the point position signals of this rotating coordinate system are converted into obstacle image images. The conversion means 14 converts the signals into point position signals in the XY coordinate system (X1, X2, Y1, Y2, Z1, Z2). In this way, the contour of the outer surface of the obstacle is detected as a plurality of point position signals. In practice, the point position signals are detected at equal pitches every “0.25 degrees” in the radial direction centered on the stereo camera 40. For convenience of explanation, however, in FIG. It is assumed that a point position signal is detected at each of the two points (X1, X2, Y1, Y2, Z1, Z2).

  Then, the obstacle image dilating means 15 makes the first, second and third diameters (L1, L2, L3) centered on the plurality of point position signals (X1, X2, Y1, Y2, Z1, Z2). A plurality of first, second and third expansion circle signals corresponding to the plurality of first, second and third expansion circles are formed. In FIG. 4, three expansion circle signals are formed for a total of six point position signals.

  Next, a “route angle signal” corresponding to an angle that is a direction in which the handy cart 1 should be advanced while avoiding an obstacle is calculated by the route acquisition unit 16 based on the plurality of first to third expansion circle signals. The

  In FIG. 4, the “first path angle θ1” is set to the first path tangent M1 with respect to the first expansion circle in the point position signal X2 of the obstacle X, and the first path tangent M1 The first path angle θ1 is calculated, and the “second path angle θ2” is set as the second path tangent M2 with respect to the second expansion circle in the point position signal Y2 of the obstacle Y, The second path angle θ2 is calculated from the path tangent M2. For the “third path angle θ3”, the third path tangent M3 is set with respect to the third expansion circle in the point position signal X1 of the obstacle X, and the third path tangent M3 The path angle θ3 is calculated.

DESCRIPTION OF SYMBOLS 1 Electric propulsion-type handy cart 2 Body frame 3 Control rod 4 Electric motor (1st electric motor)
4a Speed detection means 5 Electric motor (second electric motor)
5a Speed detection means 6, 7 Driving wheel 8 Hand grip 9 Operating force detection device 10 Control device 11 Measurement means 12 Target speed calculation means 13 Image information acquisition means (obstacle image detection means)
14 Obstacle image conversion means (obstacle image detection means)
15 obstacle image expansion means 16 route acquisition means 17 route selection means 18 avoidance signal output means 19 subtractor 20 target current calculation means 21 adder (first adjustment means)
22 Subtractor (second adjusting means)
23 First current output means 24 Second current output means 25 Adder 26 Averaging means 30 Battery 40 Image detection means (stereo camera)
41 CCD camera 42 CCD camera 50 Inclination angle detection means (gyro sensor)
60 Basket hook C case

Claims (3)

An operating rod held by a pedestrian, an operating force detection device that is provided on the operating rod and detects an operating force applied to the operating rod by the pedestrian, first and second electric motors, and the first and first First and second speed detecting means for detecting rotational speeds of the two electric motors, first and second driving wheels respectively driven to rotate by the first and second electric motors, and the operating force detection An electric handy cart comprising: a control device that supplies a control current to the first and second electric motors based on a signal from the device;
An image detection device for detecting an image of an obstacle in front of the handy cart;
The controller is
Target speed calculation means for calculating a target speed signal based on a force signal from the operating force detection device;
Averaging means for averaging the first and second detected speed signals from the first and second speed detecting means and outputting an average speed signal;
Target current calculation means for calculating a target current signal to be supplied to the electric motor based on a deviation signal between an average speed signal from the averaging means and a target speed signal from the target speed calculation means;
Obstacle image detection means for converting the contour of the obstacle into a plurality of point position signals based on the image signal of the obstacle from the image detection device;
Obstacle image expansion means for forming a plurality of expansion circle signals corresponding to a plurality of expansion circles having a predetermined diameter with the plurality of point position signals as a central position;
Based on the expansion circle signal, a path tangent that is in contact with only one of the plurality of expansion circles and is closest to the front direction line of the cart is calculated, and Route acquisition means for calculating a route angle signal that is an angle;
Avoidance signal output means for outputting an avoidance signal based on the path angle signal;
First and second adjusting means for adjusting the target current signal by adjusting the avoidance signal to adjust, and outputting first and second adjusted current signals;
Corresponding to the first and second adjustment current signals from the first and second adjustment means, a first and a second control current respectively supplied to the first and second electric motors; Second current output means ,
The obstacle image expansion means includes a plurality of first expansion circle signals corresponding to a plurality of first expansion circles having a first diameter centered on the plurality of point position signals, and the first expansion circle. Forming a plurality of second expansion circle signals corresponding to a plurality of second expansion circles of a second diameter larger than the second diameter;
The path acquisition means is in contact with only one of the plurality of first expansion circles based on the plurality of first expansion circle signals and is closest to the front direction line. 1 path tangent is calculated, a first path angle signal that is an angle between the first path tangent and the front direction line is calculated, and further, the plurality of the plurality of second expansion circle signals A second path tangent that is in contact with only one of the second expansion circles and is closest to the front direction line is calculated, and the second path tangent and the front direction line are calculated. A second path angle signal that is an angle of
The control device compares the first and second path angle signals, and selects the second path angle signal when a difference angle between the first and second path angles is less than a predetermined angle. And when the difference angle is equal to or larger than a predetermined angle, path selection means for selecting the first path angle signal is provided,
The avoidance signal output means outputs an avoidance signal based on one of the path angle signals selected from the first and second path angle signals by the path selection means. .   An image detection device for detecting an image of an obstacle, first and second electric motors, first and second drive wheels driven by the first and second electric motors, and the first and second In an electric handy cart equipped with a control device for supplying a control current to the electric motor of No. 2,
  The control device includes an obstacle image detection unit that converts an outline of an obstacle into a plurality of point position signals based on an image signal of the obstacle, and a plurality of dilations having a predetermined diameter centered on the plurality of point position signals. Obstacle image expansion means for forming a plurality of expansion circle signals corresponding to the circle, and only one of the plurality of expansion circles based on the expansion circle signal and in contact with the front direction line of the cart Route acquisition means for calculating the closest path tangent, calculating a path angle signal that is an angle between the path tangent and the front direction line, and avoidance signal output means for outputting an avoidance signal based on the path angle signal. Prepared,
  The obstacle image expansion means includes a plurality of first expansion circle signals corresponding to a plurality of first expansion circles having a first diameter centered on the plurality of point position signals, and the first expansion circle. Forming a plurality of second expansion circle signals corresponding to a plurality of second expansion circles of a second diameter larger than the second diameter;
  The path acquisition means is in contact with only one of the plurality of first expansion circles based on the plurality of first expansion circle signals and is closest to the front direction line. 1 path tangent is calculated, a first path angle signal that is an angle between the first path tangent and the front direction line is calculated, and the plurality of second expansion circle signals are further calculated based on the plurality of second expansion circle signals. A second path tangent that is in contact with only one of the second expansion circles and is closest to the front direction line is calculated, and the second path tangent and the front direction line are calculated. A second path angle signal that is an angle of the first and second path angle signals are compared, and if the difference angle between the first and second path angles is less than a predetermined angle, The second path angle signal is selected, and the difference angle is equal to or greater than a predetermined angle In some cases, route selection means for selecting the first route angle signal is provided, and the avoidance signal output means is any one selected from the first and second route angle signals by the route selection means. An electric handy cart that outputs an avoidance signal based on two path angle signals. 3. The electric handy cart according to claim 1 , wherein the obstacle image expansion means has a diameter larger than that of the second expansion circle having the point position signal as a center position. 4. Forming a plurality of third expansion circle signals corresponding to a plurality of third expansion circles of a third diameter;
The path acquisition means is in contact with only one of the plurality of third expansion circles based on the plurality of third expansion circle signals and is closest to the front direction line. Calculating a third path tangent, calculating a third path angle signal that is an angle between the third path line and the front direction line;
The route selection means compares the first and third route angle signals, and if the difference angle between the first and third route angles is less than a predetermined angle, the third route angle signal. When the difference angle is greater than or equal to the predetermined angle, the first and second path angle signals are compared, and the difference angle between the first and second path angles is less than the predetermined angle. The second path angle signal is selected, and if the difference angle is greater than or equal to the predetermined angle, the first path angle signal is selected,
The avoidance signal output means outputs an avoidance signal based on any one of the path angle signals selected from the first to third path angle signals by the path selection means. .

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