Signal processing device, cutting device, and signal processing method

Abstract

To provide a signal processing device, cutting device, and signal processing method that determine the presence or absence of an object on a road surface and determine to stop cutting the road surface depending on the presence or absence of the object.SOLUTION: A signal processing device of the embodiment includes a transmitting unit that transmits an electromagnetic wave signal toward a road surface, a receiving unit that receives a received signal based on a reflected wave corresponding to the electromagnetic wave signal, and a processing unit that determines whether or not an object is present on the road surface, and determines whether or not cutting of the road surface is to be stopped depending on the presence or absence of the object.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a signal processing device, a cutting device, and a signal processing method.

Background Art

[0002] For repairing deteriorated road surfaces, cutting devices for cutting road surfaces have been developed. When cutting a road surface, there may be objects (e.g., manhole covers) that should not be cut on the road surface. If such an object is cut, there is a possibility of damage to the object or the cutting device. Therefore, it is necessary to move the object by an operator or the like so that it is not cut. Also, depending on dust, waste materials generated by cutting, time zones, and weather, an operator or the like may overlook an object. When stopping the cutting of the road surface, it is desirable to notify the stop of the road surface cutting.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the embodiments of the present invention is to provide a signal processing device, a cutting device, and a signal processing method that notify the stop of road surface cutting when stopping the cutting of the road surface.

Means for Solving the Problems

[0005] To solve the above problems, the signal processing device of the embodiment comprises: a transmitting unit that transmits a plurality of electromagnetic wave signals toward the road surface; a receiving unit that receives a plurality of received signals based on reflected waves corresponding to the plurality of electromagnetic wave signals; a processing unit that determines to stop cutting the road surface if, among a plurality of differences in signal intensity in received signals at adjacent transmission times based on the plurality of received signals, the first difference and the second difference satisfy the conditions relating to the signal intensity of the reflected waves based on the object; and a notification unit that notifies the stopping of cutting the road surface. The condition is met if, within one hour after the first difference satisfies the first condition for signal intensity determined based on the object, the second difference satisfies the second condition for signal intensity determined based on the object, within one hour during which the signal processing device moves a distance based on the length of the object, and the distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface.

Brief Description of the Drawings

[0006] [Figure 1]A diagram showing the configuration of the cutting device 100 in the first embodiment. [Figure 2] Functional block diagram of cutting device 100. [Figure 3] A schematic diagram showing the position of the cutting device 100 at different times. [Figure 4] Figure 3 shows the signal strength and signal strength difference of the received signal based on the reflected electromagnetic wave signal. [Figure 5] Flowchart of the operation of the cutting device 100. [Figure 6] A diagram showing the configuration of a cutting device 150 applicable to the first embodiment. [Figure 7] A diagram showing the configuration of a cutting device 160 applicable to the first embodiment. [Figure 8] This diagram illustrates the case where sensor units 120a and 120b perform time-division multiplexing transmission. [Figure 9] Figure 8 illustrates the case where receiving units 122a and 122b receive data. [Figure 10] This diagram illustrates the case where sensor units 120a and 120b perform transmission by frequency division. [Figure 11] Figure 10 illustrates the case where the receiving units 122a and 122b receive received signals of frequencies f0 and f1. [Figure 12] This diagram illustrates the case where sensor units 120a and 120b perform transmission using code division. [Figure 13] This diagram illustrates the case where sensor units 120a and 120b perform transmission using phase modulation. [Figure 14] Figure 13 illustrates the case where the receiving units 122a and 122b receive received signals with phases φ0 and φ1. [Figure 15] A diagram showing the configuration of a cutting device 170 applicable to the first embodiment. [Figure 16] This diagram illustrates the case where sensor units 120a and 120c transmit electromagnetic wave signals with different polarizations. [Figure 17] Figure 16 illustrates the case where the receiving units 122a and 122c also receive a received signal whose polarization direction has changed. [Figure 18] FIG. for showing the transmission range of the electromagnetic wave signal by the sensor unit 120' and the reception range of the reception signal based on the reflected wave in the second embodiment. [Figure 19] FIG. showing the angular distribution of the signal intensity in the case of FIG. 18. [Figure 20] FIG. showing the angular distribution of the signal intensity in FIG. 3 and the difference in the angular distribution of the signal intensity. [Figure 21] FIG. for explaining the case where the frequency of the electromagnetic wave signal is changed according to time.

MODE FOR CARRYING OUT THE INVENTION

[0007] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. The disclosure is merely an example, and the invention is not limited by the content described in the following embodiments. Modifications that can be easily conceived by those skilled in the art are naturally included in the scope of the disclosure. For the sake of clarity, in the drawings, the size, shape, etc. of each part may be changed with respect to the actual embodiment and represented schematically. In a plurality of drawings, the same reference numerals may be assigned to corresponding elements, and detailed descriptions may be omitted.

[0008] (First Embodiment) FIG. 1 is a configuration diagram of a cutting device 100 in the first embodiment. FIG. 1(a) represents an xz plane view of the cutting device 100, and FIG. 1(b) represents an xy plane view of the cutting device 100. The cutting device 100 is a moving body having a road surface cutting function, and cuts the road surface while moving on the road surface. The cutting device 100 is, as an example in this embodiment, a road surface cutting vehicle, but may also be a robot or the like. The cutting device 100 transmits an electromagnetic wave signal toward the road surface at predetermined time intervals while moving. It receives a reception signal based on the reflected wave with respect to this road surface, and determines the presence or absence of an object on the road surface based on the reception signal. The object is an object on the road surface that the cutting device 100 wants to avoid cutting when cutting the road surface. For example, it is a lid of a manhole installed on the road surface. When it is determined that an object exists, the cutting device 100 stops cutting the road surface.

[0009] Figure 2 is a functional block diagram of the cutting device 100. Components of the cutting device 100 will be described using FIGS. 1 and 2. The cutting device 100 includes a vehicle body 101, a drive unit 102, a conveyor unit 103, a cutting unit 104, a storage unit 105, and a signal processing device 110. The signal processing device 110 includes a sensor unit 120, a processing unit 130, and a notification unit 140. The sensor unit 120 includes a transmission unit 121 and a reception unit 122. The processing unit 130 includes a calculation unit 131, a determination unit 132, a control unit 133, and a signal generation unit 134.

[0010] The vehicle body unit 101 is the exterior of the cutting device 100. In this embodiment, since the cutting device 100 is taken as a road surface cutting vehicle as an example, it corresponds to the exterior part and the body part of the vehicle.

[0011] The drive unit 102 drives the cutting device 100. For example, an engine, a motor, wheels, etc. The drive unit 102 receives a control signal (drive signal) from the signal generation unit 134 of the processing unit 130 and moves the cutting device 100 as a moving body, for example, in the X direction.

[0012] The conveyor unit 103 conveys the waste materials generated by cutting the road surface. Although hidden in FIGS. 1(a) and (b), the conveyor unit 103 extends in the -X direction and continues to the cutting unit 104. The waste materials carried to the conveyor unit 103 are transferred from the tip of the conveyor unit 103 to a waste material collection device or a collection location. The conveyor unit 103 operates by receiving a control signal (conveyance signal) from the signal generation unit 134 of the processing unit 130.

[0013] <000?04>The cutting unit 104 cuts the road surface. The cutting unit 104 includes a cutter drum having cutter bits which are blades for cutting the road surface, a cutter frame covering the periphery of the cutter drum, a hydraulic pump, a hydraulic cylinder, etc. for raising and lowering and rotating the cutter drum. The cutting unit 104 receives a control signal (cutting signal) from the signal generation unit 134 of the processing unit 130 and executes or stops cutting the road surface.

[0014] The transmitting unit 121 includes one or more antennas and transmits electromagnetic wave signals toward the road surface. The electromagnetic wave signals are, for example, pulse signals. The electromagnetic wave signals transmitted by the transmitting unit 121 are reflected by the road surface and become reflected waves. In this embodiment, the transmitting unit 121 transmits so that the main direction of the electromagnetic wave signals is perpendicular (in the Z direction) to the road surface. Note that perpendicular is not strictly defined as perpendicular, and a deviation such that the main direction of the received signals is toward the receiving unit 122 which is included in the same sensor unit 120 is permitted.

[0015] The receiving unit 122 includes one or more antennas and receives a received signal based on the reflected wave corresponding to the electromagnetic wave signal transmitted by the transmitting unit 121. The received signal is sent to the calculation unit 131 and used to calculate the strength of the received signal (hereinafter also referred to simply as signal strength).

[0016] The sensor unit 120, including the transmitting unit 121 and the receiving unit 122, is positioned a predetermined distance forward of the cutting unit 104 in the direction of travel (X direction). This is because, before the cutting unit 104 starts cutting, it is necessary to determine whether or not there is an object on the road surface that the cutting unit 104 will be cutting. Furthermore, the antenna used by the transmitting unit 121 and the antenna used by the receiving unit 122 may be shared or provided separately.

[0017] The calculation unit 131 calculates the signal strength based on the received signal sent from the receiving unit 122. More specifically, the calculation unit 131 converts the time from when the transmitting unit 121 transmits the electromagnetic wave signal until the receiving unit 122 receives the received signal into distance, and calculates the signal strength relative to the distance from the receiving unit. The strength of the received signal differs depending on the condition of the road surface to which the electromagnetic wave signal is reflected. For example, the received signal when reflected off the asphalt of the road surface has a higher signal strength than the received signal when reflected off a manhole cover as an object on the road surface. The calculation unit 131 stores the calculated signal strength in the storage unit 105.

[0018] Furthermore, the calculation unit 131 calculates the difference in signal strength between multiple received signals sent from the receiving unit 122. When the transmitting unit 121 transmits multiple electromagnetic wave signals according to time, the receiving unit 122 receives multiple received signals according to time. The calculation unit 131 calculates the signal strength of each of these multiple received signals and stores it in the storage unit 105. The calculation unit 131 calculates the difference in signal strength between multiple received signals (hereinafter also referred to simply as the difference in signal strength) by taking the difference in the multiple signal strengths. The difference in signal strength is sent to the determination unit 132 and used to determine the presence or absence of an object on the road surface.

[0019] The determination unit 132 determines the presence or absence of an object on the road surface based on the received signal received by the receiving unit 122. More specifically, the determination unit 132 uses the difference in signal intensity sent from the calculation unit 131 to determine the presence or absence of an object on the road surface by comparing the difference in signal intensity with a preset threshold. The determination unit 132 stores the difference in signal intensity sent from the calculation unit 131 in the storage unit 105. The determination unit 132 sends the information regarding the presence or absence of an object on the road surface, which has been determined, to the control unit 133.

[0020] The processing unit 130 commands the operation of the drive unit 102, the conveyor unit 103, and the cutting unit 104. The control unit 133 instructs the signal generation unit 134 to generate a control signal including this command and to transmit it to the component targeted by the command. The control signal is collectively referred to as the drive signal including the command to the drive unit 102, the transport signal including the command to the conveyor unit 103, and the cutting signal including the command to the cutting unit 104.

[0021] The control unit 133 instructs the signal generation unit 134 to generate an electromagnetic wave signal so that the transmission unit 121 transmits the electromagnetic wave signal toward the road surface. The control unit 133 also instructs the signal generation unit 134 to start and stop the generation of the electromagnetic wave signal.

[0022] Furthermore, based on the information sent from the determination unit 132 regarding the presence or absence of an object on the road surface, the control unit 133 decides whether to stop or continue cutting the road surface by the cutting unit 104 depending on the presence or absence of an object. If an object is present, the cutting unit 104 stops cutting the road surface; if no object is present, the cutting unit 104 is instructed to continue cutting the road surface. The control unit 133 instructs the signal generation unit 134 to generate a cutting signal that includes an instruction to stop or continue cutting the road surface. Also, if the control unit 133 decides to stop cutting the road surface by the cutting unit 104, it instructs the signal generation unit 134 to generate a notification signal that notifies the system of the cessation of road surface cutting.

[0023] The signal generation unit 134 generates electromagnetic wave signals, control signals, and notification signals in response to commands from the control unit 133, and transmits them to the components targeted by the commands. The signal generation unit 134 generates an electromagnetic wave signal to be transmitted toward the road surface. The electromagnetic wave signal is sent to the transmission unit 121. The signal generation unit 134 generates control signals that command the operation of the drive unit 102, the conveyor unit 103, and the cutting unit 104, respectively. The generated control signals are sent to the components targeted by the commands (drive unit 102, conveyor unit 103, or cutting unit 104). The cutting signal sent to the cutting unit 104 includes an instruction to stop or start cutting the road surface, which is determined by the control unit 133 depending on the presence or absence of an object. The signal generation unit 134 generates a notification signal to notify that the cutting of the road surface has stopped and sends it to the notification unit 140.

[0024] The notification unit 140 notifies those around it that the road surface cutting has stopped based on the notification signal. The notification unit 140 may notify using light such as a lamp, sound such as a siren, display on an operation display such as a monitor, or a combination of these. The notification from the notification unit 140 allows workers around the cutting device 100 to recognize that the cutting of the road surface by the cutting unit 104 has stopped and that there are objects around the cutting unit 104.

[0025] The memory unit 105 stores the signal strength and the difference in signal strength calculated by the calculation unit 131. The memory unit 105 is a memory, such as RAM (Random Access Memory), PROM (Programmable ROM), EPROM (Erasable PROM), EEPROM (Electrically EPROM), flash memory, or registers. The memory unit 103 may be located inside the wireless communication device 100A or located outside. If located outside, the memory unit 103 may be a cloud that stores information via the internet.

[0026] The configuration of the cutting device 100 has been described above. At least some of the components of the signal processing device 110 may be implemented on a physically integrated semiconductor integrated circuit (LSI, etc.). Also, in Figure 2, the calculation unit 131, the determination unit 132, the control unit 133, and the signal generation unit 134 are included in the processing unit 130. The processing unit 130 is one or more electronic circuits including a control device and an arithmetic unit. The electronic circuit can be implemented as an analog or digital circuit, etc. For example, a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), an ASIC, an FPGA, or a combination thereof is possible. Also, the processing unit 130 may be executed by software using these electronic circuits. Furthermore, the unit that commands the drive unit 102 and the conveyor unit 103 may be provided separately from the processing unit 130.

[0027] Figure 3 is a schematic diagram of the position of the cutting device 100 at different times. The operation of the cutting device 100 will be explained using Figures 3 to 5. The cutting device 100 transmits an electromagnetic wave signal toward the road surface at predetermined intervals and receives a received signal based on the reflected wave from the road surface. Based on the received signal, the cutting device 100 determines whether or not there is an object on the road surface. The cutting device 100 decides whether or not to stop cutting the road surface depending on the presence or absence of the object. If an object is present on the road surface to be cut, the cutting device 100 stops cutting the road surface; if no object is present, it performs or continues cutting the road surface. In Figure 3, electromagnetic wave signals are transmitted at times t0, t1, t2, t3, t4, and t5. The cutting device 100 (including the signal processing device 110) moves in the X direction at a moving speed V while cutting the road surface, and the position of the cutting device 100 at time t0 is X0, the position of the cutting device 100 at time t1 is X1, ..., and the position of the cutting device 100 at time t5 is X5. Therefore, time t0 corresponds to position X0, time t1 corresponds to position X1, ... time t5 corresponds to position X5.

[0028] In this embodiment, the position of the cutting device 100 is defined as the position of the sensor unit 120 (the X-coordinate of the road surface from which the electromagnetic wave signal is transmitted). Furthermore, Zr is the distance in the Z direction from the sensor unit 120 to the road surface, L is the length of the object in the X direction, and d is the distance from the sensor unit 120 to the cutting unit 104. When determining distance d, the cutting unit 104 is based on the end closest to the sensor unit 120. The object is assumed to be located within the range of X2 to X4. Additionally, the road surface other than the object is assumed to be asphalt, and the received signal based on the reflected wave from the object is assumed to have a higher intensity than the received signal based on the reflected wave from the asphalt.

[0029] Figure 4 shows the signal strength (hereinafter also referred to as the signal strength at time tx or the signal strength at time tx) and the difference in signal strength of the received signal based on the reflected waves of the electromagnetic wave signals transmitted at times t0, t1, ..., t5 in Figure 3. At each of the times t0 to t5, the cutting device 100 transmits an electromagnetic wave signal to each of the positions X0 to X5. In this embodiment, the electromagnetic wave signal is a pulse signal. The cutting device 100 receives a received signal based on the reflected waves of this electromagnetic wave signal. The cutting device 100 calculates the relationship between the Z direction and the signal strength (also simply referred to as the signal strength) by converting the time from the transmission of the electromagnetic wave signal to the reception of the received signal into distance.

[0030] The signal intensity for each time point t0 to t5 shows a peak at Z=Zr. As shown in Figure 3, since Zr is the distance from the sensor unit 120 to the road surface, this peak at Z=Zr is based on the reflected electromagnetic wave.

[0031] Here, for positions X0, X1, and X5, the peak signal intensity at Z=Zr is Sr (hereinafter also referred to as intensity Sr). Since the road surface at positions X0, X1, and X5 is asphalt, the intensity Sr takes a relatively small value.

[0032] On the other hand, for positions X2 and X4, the peak signal intensity at Z=Zr is Sm1 (hereinafter also referred to as intensity Sm1), and for position X3, the peak signal intensity at Z=Zr is Sm2 (hereinafter also referred to as intensity Sm2). Since objects are present on the road surface at positions X2 to X4, intensities Sm1 and Sm2 are higher than intensity Sr.

[0033] The difference in signal intensity can be calculated by taking the difference in the Z-direction between the signal intensity at adjacent times. For example, if we take the difference between the signal intensity at time t0 and the signal intensity at time t1, no change in signal intensity is observed. This indicates that there is no change in the type of road surface reflecting the signal between times t0 and t1. Therefore, at time t1, the cutting device 100 does not determine that there is an object on the road surface and continues cutting.

[0034] At time t2, the difference between the signal intensity at time t1 and the signal intensity at time t2 shows a change in signal intensity with a peak at Z=Zr. This peak is greater than a predetermined threshold + DS. The threshold + DS is set as the first condition regarding signal intensity. Note that the first condition may also be called the first condition regarding the difference in signal intensity. Satisfying this condition indicates that at the location of the cutting device 100 (sensor unit 120), the surface switched from asphalt to an object that reflects light similarly to the target object between times t1 and t2. At time t2, when the peak of the difference in signal intensity becomes greater than the threshold + DS, the cutting device 100 generates a flag (hereinafter simply referred to as the flag) indicating the possibility that the cutting device 100 is on the target object. The cutting device 100 holds this flag. Note that at time t2, the determination of whether it is a target object, which will be described later as the second condition, has not yet been made, so the cutting unit 104 continues cutting.

[0035] At time t3, the difference between the signal intensity at time t2 and the signal intensity at time t3, and at time t4, the difference between the signal intensity at time t3 and the signal intensity at time t4, similarly, a change in signal intensity appears with a peak at Z=Zr. However, these peaks are greater than a predetermined threshold -DS and less than the threshold +DS. In this case, the threshold -DS is set as the second condition regarding signal intensity. Note that the second condition may also be called the second condition regarding the difference in signal intensity. Satisfying this condition indicates that the position of the cutting device 100 has switched from an object that reflects like the target object to asphalt between the two time points. Therefore, the cutting device 100 is still on an object that reflects like the target object at times t3 and t4. The cutting device 100 retains the flag generated at time t2. Thus, at times t3 and t4, although the position of the cutting device 100 is on an object that reflects like the target object, it cannot be definitively determined to be the target object, so cutting continues.

[0036] Here, the flag retention period is predetermined. The flag retention period is set based on the maximum length Lmax of the object to be determined and the time calculated from the movement speed V of the cutting device 100. The length Lmax is, for example, the maximum diameter of a manhole cover. Note that the length Lmax is shorter than the distance d from the sensor unit 120 to one end of the cutting unit 104. If the length Lmax is longer than the distance d, there is a possibility that the object will be caught in the cutting by the cutting unit 104. If the second condition is not met during the flag retention period, the cutting device 100 determines that it is not an object and clears the flag. By setting a flag retention period, the presence or absence of an object can be determined before it is cut by the cutting unit 104.

[0037] At time t5, taking the difference between the signal intensity at time t4 and the signal intensity at time t5, a similar change in signal intensity appears with a peak at Z=Zr. This peak is smaller than a predetermined threshold -DS. Between the two time points, the position of the cutting device 100 has switched from an object that reflects light similar to the target object to asphalt. Here, if time t5 is within the flag holding period, the cutting device 100 determines that the second condition is met within the flag holding period and that the target object is present on the road surface. The cutting device 100 stops cutting the road surface and notifies that cutting of the road surface has stopped.

[0038] As described above, even when the cutting device 100 moves along the road surface at a moving speed V while cutting the road surface, it can stop or start cutting the road surface depending on the presence or absence of an object, without cutting the object itself. Figure 3 also shows that at time t5, the object does not come into contact with the cutting unit 104.

[0039] Figure 5 is a flowchart of the operation of the cutting device 100. Using Figure 5, we will explain in detail the operation related to stopping the cutting of the road surface by the cutting unit 104 of the cutting device 100. As a premise, it is assumed that the cutting device 100 is cutting the road surface while moving in the direction of travel at a travel speed V. The processes of steps S101 to S114 described below are performed each time an electromagnetic wave signal is transmitted, and the process returns to step S101 or terminates before the next electromagnetic wave signal is transmitted.

[0040] The transmitting unit 121 transmits an electromagnetic wave signal toward the road surface (step S101). This electromagnetic wave signal is generated by the signal generation unit 134, which receives a command from the control unit 133, and sent to the transmitting unit 121. The transmitting unit 121 transmits the electromagnetic wave signal at predetermined intervals. This predetermined interval is arbitrarily determined according to the accuracy of determining the presence or absence of an object, the moving speed V of the cutting device 100, the signal processing capability of the cutting device 100, etc. For example, in Figures 3 and 4, the transmitting unit 121 transmits an electromagnetic wave signal at times t0, t1, ..., t5.

[0041] The receiving unit 122 receives a received signal based on the reflected electromagnetic wave signal from the road surface transmitted by the transmitting unit 121 (step S102). The received signal is sent to the calculation unit 131.

[0042] The calculation unit 131 calculates the signal strength from the received signal sent from the receiving unit 122 (step S103). The calculation unit 131 stores the calculated signal strength in the storage unit 105. For example, in Figure 4, the calculation unit 131 calculates the signal strength at times t0, t1, ..., t5.

[0043] The calculation unit 131 checks whether past signal strengths are stored in the storage unit 105 (step S104). The past signal strengths should preferably be those of adjacent electromagnetic wave signal transmission times, but they may also be those of electromagnetic wave signal transmission times within a predetermined time range. If the storage unit 105 does not store past signal strengths (step S104: No), the calculation unit 131 returns to step S101. For example, in Figures 3 and 4, when the calculation unit 131 calculates the signal strength at time t0, the storage unit 105 does not store the signal strengths of past received signals. In such cases, the calculation unit returns to step S101.

[0044] On the other hand, if the memory unit 105 has past signal strengths (step S104: Yes), the calculation unit 131 calculates the difference in signal strength between multiple signal strengths. For example, in Figure 4, when the calculation unit 131 calculates the signal strength at times t1 to t5, the memory unit 105 holds past signal strengths. The calculation unit 131 calculates the difference between the signal strength at time t0 and the signal strength at time t1. Similarly, for times t2 to t5, the calculation unit 131 calculates the difference between the signal strength at the transmission time of adjacent electromagnetic wave signals in the past. The calculation unit 131 sends the calculated difference in signal strength to the determination unit 132.

[0045] The determination unit 132 determines the presence or absence of an object on the road surface from the difference in signal intensity sent from the calculation unit 131. The determination of the presence or absence of an object is performed in steps S106 to S112. First, the determination unit 132 checks in the storage unit 105 whether a flag indicating that the first condition regarding the difference in signal intensity is met is held (step S106). In this embodiment, as an example, this flag indicates that the difference in signal intensity is greater than the positive threshold (+DS), representing the possibility that the cutting device 100 is located on an object. If the flag is not held (step S106: No), the determination unit 132 checks whether the difference in signal intensity meets the first condition (step S107). In this embodiment, as an example, the determination unit 132 checks whether the difference in signal intensity is greater than the positive threshold (+DS) by comparing it. If the difference in signal strength satisfies the first condition (step S108: Yes), the determination unit 132 generates a flag, stores it in the storage unit 105 along with the flag generation time (step S108), and returns to step S101. If the difference in signal strength does not satisfy the first condition (step S108: No), returns to step S101.

[0046] On the other hand, if the flag is held in the memory unit 105 (step S106: Yes), the decision unit 132 checks whether the current time is within the flag retention period from the time the flag was generated (step S109). If the current time is not within the flag retention period (step S109: No), the decision unit 132 erases the flag from the memory unit 105 (step S110) and returns to step S101.

[0047] The reason the determination unit 132 checks whether the flag is within its retention period is that if the flag retention period is exceeded, there is a high possibility of misrecognition of the object. For example, the difference using the signal strength of the received signal reflected by the white line on the road surface may be greater than the threshold + DS, but if this white line extends in the direction of travel of the cutting device 100, it may exceed the maximum length Lmax that can be assumed for a manhole cover. In this case, even if it subsequently becomes smaller than the threshold - DS, the determination unit 132 should not determine that the object (manhole cover) is present on the road surface. By checking whether the flag is within its retention period, the determination unit 132 can avoid misrecognition of the object.

[0048] If the current time is within the flag retention period (step S109: Yes), the determination unit 132 checks whether the difference in signal strength satisfies the second condition regarding the difference in signal strength (step S111). In this embodiment, as an example, the determination unit 132 checks whether the difference in signal strength is smaller than the negative threshold (-DS). If the difference in signal strength satisfies the second condition (step S111: No), the process returns to step S101.

[0049] On the other hand, if the difference in signal intensity does not satisfy the second condition (step S111: No), the determination unit 132 determines that an object exists on the road surface (step S112). The determination unit 132 sends information to the control unit 133 indicating that an object exists on the road surface as information regarding the presence or absence of an object.

[0050] The control unit 133 receives information from the determination unit 132 indicating that an object exists on the road surface and instructs the signal generation unit 134 to generate a cutting signal to stop the cutting unit 104 and a notification signal to notify the cutting unit 104 of the stoppage (step S113). The signal generation unit 134 receives the command from the control unit 133 and generates a cutting signal to stop the cutting unit 104 and sends it to the cutting unit 104, and generates a notification signal and sends it to the notification unit 140.

[0051] The cutting unit 104 stops cutting the road surface upon receiving a cutting signal from the signal generation unit 134, and the notification unit 140, upon receiving a notification signal from the signal generation unit 134, notifies that the cutting unit 104 has stopped (step S114). The notification unit 140 notifies workers around the cutting device 100 of the stoppage of the cutting unit 104 using, for example, light, sound, or a display on a screen.

[0052] The control unit 133 checks whether or not a termination command has been received to terminate the operation of the cutting device 100 (step S115). This termination command is a command to terminate the operation of the cutting device 100 in this flow. This termination command is transmitted to the control unit 133 by input to the cutting device 100 by an operator or by the cutting device 100 acquiring a signal containing the termination command. This termination command may be a command to immediately terminate the operation of the cutting device 100.

[0053] If the control unit 133 has not received this termination command (step S115: No), the process returns to step S101. On the other hand, if the control unit 133 has received this termination command (step S115: Yes), the process ends and the cutting device 100 ceases operation.

[0054] The operation of the cutting apparatus 100 in this embodiment has been described above. The cutting apparatus 100 described in this embodiment is just one example, and various modifications can be implemented and executed. Modifications of this embodiment are described below.

[0055] (Variation 1) When the transmitting unit 121 transmits an electromagnetic wave signal toward the road surface, it is desirable that the main direction of the electromagnetic wave signal be perpendicular to the road surface so that the reflected waves from the road surface are strong. Also, when the receiving unit 122 receives a received signal based on the reflected waves corresponding to the electromagnetic wave signal, it is desirable that the receiving surface of the receiving unit 122 be perpendicular to the main direction of the received signal in order to facilitate reception.

[0056] The transmitting unit 121 and the receiving unit 122 may be able to change their angles according to commands from the control unit 133. The control unit 133 recognizes the angles of the road surface, the transmitting unit 121, and the receiving unit 122 using any method, such as angle information from an angle sensor or a photograph. Based on the recognized angles, the control unit 133 may command the angle of the transmitting unit 121 so that the main direction of the electromagnetic wave signal transmitted by the transmitting unit 121 is perpendicular to the road surface, and command the angle of the receiving unit 122 so that the receiving surface of the receiving unit 122 is perpendicular to the main direction of the received signal. Signals containing these commands are generated by the signal generation unit 134 and sent to the transmitting unit 121 and the receiving unit 122.

[0057] (Modification 2) In this embodiment, in step S103, the calculation unit 131 calculates the signal strength based on the received signal and stores it in the storage unit 105. If, as a result of calculating the signal strength, the peak of the signal strength is outside a predetermined range from Z=Zr, the calculation unit 131 may discard the signal strength instead of storing it in the storage unit 105. As shown in Figure 3, in this embodiment, Zr is the distance from the sensor unit 120 to the road surface. In this case, if the peak of the signal strength is outside a predetermined range from Z=Zr, it is possible that the electromagnetic wave signal is a received signal reflected from an object other than the road surface (including the object). In this case, since it may adversely affect the determination of whether or not there is an object on the road surface, the calculation unit 131 may discard signal strengths whose peaks are outside a predetermined range from Z=Zr.

[0058] (Variation 3) In this embodiment, the calculation unit 131 calculates the difference in signal intensity in step S105, and the determination unit 132 determines the presence or absence of the object based on the difference in signal intensity. The determination unit 132 may also determine the presence or absence of the object based on the signal intensity calculated by the calculation unit 131 in step S103.

[0059] In this case, if the signal strength exceeds a predetermined threshold (for example, threshold DS'), the determination unit 132 generates a flag, indicating that the first condition is met. If the signal strength falls below threshold DS' within the flag retention period, the determination unit 132 may determine that the object exists, indicating that the second condition is met.

[0060] (Modification 4) In this embodiment, in steps S107 and S111, the first condition regarding the difference in signal intensity was compared as being greater than the threshold + DS, and the second condition regarding the difference in signal intensity was compared as being less than the threshold - DS. However, these conditions are not limited to being greater than or less than the threshold. For example, if an evaluation value is calculated for the difference in signal intensity, and a smaller evaluation value indicates a larger difference in signal intensity, then the first condition would be compared as being less than the threshold, and the second condition would be compared as being greater than the threshold. In addition, the first and second conditions may be set based on fluctuations in the evaluation value. For the first condition, any condition can be applied as long as it can be determined from the difference in signal intensity that the position of the cutting device 100 has moved from the road surface (asphalt) to an object that reflects light in the same way as the target object. Similarly, for the second condition, any condition can be applied as long as it can be determined from the difference in signal intensity that the position of the cutting device 100 has moved from an object that reflects light in the same way as the target object to the road surface (asphalt). Furthermore, if the difference in signal intensity is an absolute value, the first and second conditions may be the same.

[0061] (Variation 5) In this embodiment, in step S113, the control unit 133 receives information from the decision unit 132 indicating the presence of an object on the road surface and decides to stop the cutting of the road surface by the cutting unit 104. The control unit 133 may decide to continue (including continuing) the cutting of the road surface by the cutting unit 104 as long as it has not received information from the decision unit 132 indicating the presence of an object on the road surface. The control unit 133 instructs the signal generation unit 134 to generate a cutting signal for the cutting unit 104 to cut the road surface. The signal generation unit 134 generates a cutting signal including an instruction to cut the road surface and sends it to the cutting unit 104. The cutting unit 104 receives this cutting signal and performs cutting of the road surface.

[0062] (Experimental variation 6) In this embodiment, the transmitting unit 121 of the sensor unit 120 transmits an electromagnetic wave signal perpendicular to the road surface, and the receiving unit 122, which is also included in the sensor unit 120, receives the received signal. Depending on the vehicle body 101 to which the sensor unit 120 is attached, the sensor unit 120 may not be able to be installed parallel to the road surface, and the electromagnetic wave signal transmitted from the transmitting unit 121 may not be able to be transmitted perpendicular to the road surface. In this case, multiple sensor units 120 may be used, with one sensor unit 120a transmitting an electromagnetic wave signal toward the road surface and the other sensor unit 120b receiving the received signal.

[0063] Figure 6 is a diagram showing the configuration of a cutting device 150 equipped with multiple sensor units 120, namely sensor units 120a and 120b. Hereafter, sensor unit 120a is the same as sensor unit 120 in this embodiment and includes a transmitting unit 121a and a receiving unit 122a. Similarly, sensor unit 120b also includes a transmitting unit 121b and a receiving unit 122b. The transmitting unit 121a transmits an electromagnetic wave signal to the road surface. The receiving unit 122b is installed considering the angle of incidence of the electromagnetic wave signal to the road surface and the angle of reflection by the road surface in order to receive a received signal based on the reflected wave of this electromagnetic wave signal. In Figure 6, it is provided on the conveyor unit 103. The receiving unit 122b receives a received signal based on the reflected wave of this electromagnetic wave signal. The subsequent operation is the same as in this embodiment, so the explanation is omitted.

[0064] In this way, even if the sensor unit 120 cannot be installed parallel to the road surface due to the tilt of the vehicle body 101 to which the sensor unit 120 is attached, signal processing can be performed in the same manner as in this embodiment.

[0065] Alternatively, the transmitting unit 121b may transmit an electromagnetic wave signal, and the receiving unit 122a may receive the received signal. Furthermore, even if there are not multiple sensor units 120, and even if the transmitting unit 121 and the receiving unit 122 are installed separately, signal processing can be performed in the same manner as in this modified example.

[0066] (Example 7) In this embodiment, the sensor unit 120 was installed in the center of the width (Y direction) of the cutting device 100. Since the electromagnetic wave signal transmitted by the transmitter unit 121 is directional, depending on the distance Zr from the sensor unit 120 to the road surface, it may not be able to cover the width of the cutting device. In this case, multiple sensor units 120 may be used and installed at different positions in the width direction (Y direction) of the cutting device 100.

[0067] Figure 7 is a diagram showing the configuration of a cutting device 160, which includes multiple sensor units 120, namely sensor units 120a and 120b. Transmitting units 121a and 121b each transmit electromagnetic wave signals, and receiving units 122a and 122b each receive at least one of the received signals based on the reflected electromagnetic wave signals transmitted by transmitting unit 121a and the received signals based on the reflected electromagnetic wave signals transmitted by transmitting unit 121a.

[0068] The following describes an example of when multiple transmitting units 121a and 121b transmit electromagnetic wave signals. When transmitting electromagnetic wave signals, there are various methods such as time-division multiplexing, frequency-based transmission, code-division multiplexing, and phase-modulation transmission. Any of these may be applied to this embodiment, or they may be applied in combination.

[0069] (Example 7.1) Figure 8 illustrates the case where sensor units 120a and 120b perform time-division multiplexing transmission. If the electromagnetic wave signals transmitted by transmitter units 121a and 121b have similar frequencies, simultaneous transmission may cause interference between them, potentially negatively affecting the determination of whether or not an object is present.

[0070] Therefore, interference between electromagnetic wave signals is suppressed by dividing the time at which the transmitting units 121a and 121b transmit electromagnetic wave signals (time division). The time at which the transmitting units 121a and 121b each transmit electromagnetic wave signals is determined by the control unit 133 and commanded to the transmitting units 121a and 121b through the signal generation unit 134.

[0071] For example, in Figure 8(a), at time t0, the transmitter 121a transmits an electromagnetic wave signal. The receiver 122a receives a received signal based on the reflected wave of this electromagnetic wave signal. At time t0, the transmitter 121b does not transmit an electromagnetic wave signal. On the other hand, in Figure 8(b), at time t1, the transmitter 121b transmits an electromagnetic wave signal. The receiver 122b receives a received signal based on the reflected wave of this electromagnetic wave signal. At time t1, the transmitter 121a does not transmit an electromagnetic wave signal. Similarly thereafter, at time 2n (where n is a non-negative integer), the transmitter 121a transmits an electromagnetic wave signal, and at time 2n+1, the transmitter 121b transmits an electromagnetic wave signal.

[0072] The operation of the cutting device 160 after receiving the received signal is the same as that of the cutting device 100. Here, the calculation unit 131 may divide the received signal into multiple groups for calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide the received signal into group A at time 2n when the transmitting unit 121a transmits the electromagnetic wave signal and group B at time 2n+1 when the transmitting unit 121b transmits the electromagnetic wave signal, and calculate the signal strength and the difference in signal strength. This makes it possible to determine whether or not an object exists at the Y-direction position where the sensor units 120a and 120b are installed, respectively. The determination unit 132 determines that an object exists if at least one of group A and group B satisfies the first and second conditions.

[0073] Furthermore, in the time-division method, the receiving units 122a and 122b may receive even if the transmitting units 120a and 120b, which belong to the same sensor unit 120, do not transmit electromagnetic wave signals. Figure 9 illustrates the case where the receiving units 122a and 122b receive the signal.

[0074] In Figure 9(a), at time t0, the transmitter 121a transmits an electromagnetic wave signal, and the receivers 122a and 122b receive a received signal based on the reflected wave of this electromagnetic wave signal. In Figure 9(b), at time t1, the transmitter 121b transmits an electromagnetic wave signal, and the receivers 122a and 122b receive a received signal based on the reflected wave of this electromagnetic wave signal. The subsequent operation is the same as described in Figure 8.

[0075] The receiving unit 122b is at a greater distance from the transmitting unit 121a than the receiving unit 122a, and the receiving unit 122a is at a greater distance from the transmitting unit 121b than the receiving unit 122b. However, the main direction of the received signal may change depending on the unevenness of the road surface or the unevenness of the object. Receiving signals with both the receiving unit 122a and the receiving unit 122b can reduce reception errors.

[0076] The calculation unit 131 may further divide the received signals at time 2n (group A) and at time 2n+1 (group B) into multiple groups when calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide group A into group A1 of received signals received by the receiving unit 122a and group A2 of received signals received by the receiving unit 122b. The calculation unit 131 may also divide group B into group B1 of received signals received by the receiving unit 122a and group B2 of received signals received by the receiving unit 122b.

[0077] The calculation unit 131 calculates the signal strength and the difference in signal strength for each of the groups A1, A2, B1, and B2, and the determination unit 132 may determine the presence or absence of the object based on the difference in signal strength of these groups. For example, the determination unit 132 determines that the object exists if at least one of the groups A1, A2, B1, and B2 satisfies the first and second conditions.

[0078] Furthermore, the calculation unit 131 may select the received signal with the higher signal strength from the two received signals of groups A1 and A2 at the same time, and calculate the signal strength and the difference in signal strength for group A'. Similarly, the calculation unit 131 may select the received signal with the higher signal strength for groups B1 and B2 at the same time, and calculate the signal strength and the difference in signal strength for group B'. The determination unit 132 determines that an object exists if at least one of groups A' and B' satisfies the first and second conditions.

[0079] Furthermore, when generating group A', the calculation unit 131 may combine the two received signals from groups A1 and A2 at the same time. When generating group B', the calculation unit 131 may combine the two received signals from groups B1 and B2 at the same time.

[0080] (Example 7.2) Figure 10 illustrates the case where sensor units 120a and 120b perform transmission by frequency division. Transmitting units 121a and 121b can obtain a received signal without interference between electromagnetic signals by setting the frequencies of the electromagnetic wave signals they transmit to different frequencies (frequency division).

[0081] For example, in Figure 10, the transmitter 121a transmits an electromagnetic wave signal with frequency f0, and the transmitter 121b transmits an electromagnetic wave signal with frequency f1. The receiver 122a receives a received signal based on the reflected wave of the electromagnetic wave signal with frequency f0, and the receiver 122b receives a received signal based on the reflected wave of the electromagnetic wave signal with frequency f1. Here, during the signal reception processing, the receiver 122a can extract and receive the signal with frequency f0, and the receiver 122b can extract and receive the signal with frequency f1. Therefore, even when the transmitters 121a and 121b transmit electromagnetic wave signals simultaneously, the received signal based on the reflected wave of the electromagnetic wave signal with frequency f0 and the received signal based on the reflected wave of the electromagnetic wave signal with frequency f1 are distinguished and received.

[0082] The operation of the cutting device 160 after receiving the received signal is the same as that of the cutting device 100. Here, the calculation unit 131 may divide the received signal into multiple groups for calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide the received signal into group C, which is based on the reflected wave of an electromagnetic wave signal of frequency f0, and group D, which is based on the reflected wave of an electromagnetic wave signal of frequency f1, and calculate the signal strength and the difference in signal strength. This makes it possible to determine whether or not an object exists at the Y-direction position where the sensor units 120a and 120b are installed, respectively. The determination unit 132 determines that an object exists if at least one of group C and group D satisfies the first and second conditions.

[0083] Furthermore, in the frequency division method, the receiving units 122a and 122b may receive the received signal of frequency f0 and the received signal of frequency f1. Figure 11 illustrates the case where the receiving units 122a and 122b receive the received signal of frequency f0 and the received signal of frequency f1. During the signal reception processing, the receiving units 122a and 122b can receive the signal of frequency f0 and the signal of frequency f1 separately. This reduces reception errors of the received signal, even if the main direction of the received signal changes due to irregularities in the road surface or the object.

[0084] The calculation unit 131 may further divide the received signals from group C and group B into multiple groups when calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide group C into group C1 of received signals received by the receiving unit 122a and group C2 of received signals received by the receiving unit 122b. The calculation unit 131 may also divide group D into group D1 of received signals received by the receiving unit 122a and group D2 of received signals received by the receiving unit 122b.

[0085] The calculation unit 131 calculates the signal strength and the difference in signal strength for each of the groups C1, C2, D1, and D2, and the determination unit 132 may determine the presence or absence of the object based on the difference in signal strength of these groups. For example, the determination unit 132 determines that the object exists if at least one of the groups C1, C2, D1, and D2 satisfies the first and second conditions.

[0086] Furthermore, the calculation unit 131 may select the received signal with the higher signal strength from the two received signals of groups C1 and C2 at the same time, and calculate the signal strength and the difference in signal strength for group C'. Similarly, the calculation unit 131 may select the received signal with the higher signal strength for groups D1 and D2 at the same time, and calculate the signal strength and the difference in signal strength for group D'. The determination unit 132 determines that an object exists if at least one of groups C' and group D' satisfies the first and second conditions.

[0087] Furthermore, when generating group C', the calculation unit 131 may combine the two received signals from groups C1 and C2 at the same time. When generating group D', the calculation unit 131 may combine the two received signals from groups D1 and D2 at the same time.

[0088] (Example 7.3) Figure 12 illustrates the case where sensor units 120a and 120b perform transmission using code division. Transmitting units 121a and 121b, even when transmitting electromagnetic wave signals of similar frequencies and simultaneously, can extract received signals based on the reflected waves of the electromagnetic wave signals transmitted by each unit by assigning a specific code (code division) to the electromagnetic wave signals they transmit.

[0089] The timing at which each of the transmitting units 121a and 121b transmits an electromagnetic wave signal is determined by the control unit 133 and instructed to the transmitting units 121a and 121b via the signal generation unit 134.

[0090] At time t0, transmitters 121a and 121b transmit electromagnetic wave signals. These electromagnetic wave signals are assigned the same code. For example, in Figure 12(a), the electromagnetic wave signals transmitted by transmitters 121a and 121b are assigned the code +1 at time t0 (CodeA_t0=+1, CodeB_t0=+1). The + code is a code that strengthens the intensity of a signal when signals are superimposed.

[0091] At time t1, transmitters 121a and 121b transmit electromagnetic wave signals. These electromagnetic wave signals are each assigned an inverted code. For example, in Figure 12(b), the electromagnetic wave signal transmitted by transmitter 121a is assigned the code +1 at time t1 (CodeA_t1=+1). On the other hand, the electromagnetic wave signal transmitted by transmitter 121b is assigned the code -1 at time t1, which is the inverted code of +1 (CodeB_t1=-1). The - code weakens the intensity of the signal when signals are superimposed.

[0092] The receiving units 122a and 122b receive a superimposed signal which is a received signal a based on the reflected electromagnetic wave signal transmitted by the transmitting unit 121a and a received signal b based on the reflected electromagnetic wave signal transmitted by the transmitting unit 121b.

[0093] Here, we assume that if the intensity of the transmitted electromagnetic wave signal is the same regardless of time, then the intensity of the received signal based on the reflected wave of that electromagnetic wave signal will also be the same. In this case, let Ya (hereinafter also be referred to as received signal Ya) be the absolute value of the intensity of the received signal (the received signal to be extracted) based on the reflected wave of the electromagnetic wave signal transmitted by transmitter 121a, and Yb (hereinafter also referred to as received signal Yb) be the absolute value of the intensity of the received signal (the received signal to be extracted) based on the reflected wave of the electromagnetic wave signal transmitted by transmitter 121b. Let Yt0 (hereinafter also be referred to as superimposed signal Yt0) be the intensity of the superimposed signal at time t0, and Yt1 (hereinafter also referred to as superimposed signal Yt1) be the intensity of the superimposed signal at time t1, as received by receivers 122a and 122b. The relationship between received signals Ya, Yb, and superimposed signals Yt0 and Yt1 is expressed in the following equation (1).

number

[0094] The calculation unit 131 calculates and extracts the received signals Ya and Yb from the superimposed signals Yt0 and Yt1. Solving equation (1) for the received signals Ya and Yb yields the following equation (2).

number

[0095] Based on the calculation in equation (2), the calculation unit 131 calculates the received signals Ya and Yb at times t0 to t1. At time t2, both the transmitting units 121a and 121b transmit electromagnetic wave signals with a sign of +1, and the receiving units 122a and 122b receive the superimposed signal (Yt2). In the same manner as in equation (2), the calculation unit 131 calculates the received signals Ya' and Yb' at times t1 to t2. Subsequently, as in this embodiment, the calculation unit 131 calculates the signal strength and the difference in signal strength, and the determination unit 132 determines the presence or absence of the object.

[0096] Here, the calculation unit 131 may divide the calculated received signals into multiple groups for calculating the signal strength and the difference in signal strength. The calculation unit 131 divides the received signals into group E of the received signal Ya and group F of the received signal Yb, and calculates the signal strength and the difference in signal strength. This makes it possible to determine whether or not an object exists at the Y-direction positions where the sensor units 120a and 120b are installed, respectively. The determination unit 132 determines that an object exists if at least one of group E and group F satisfies the first and second conditions.

[0097] Furthermore, the calculation unit 131 may calculate the received signals Ya and Yb for each receiving unit that receives the superimposed signal. This reduces reception errors of the received signal by allowing reception by both the receiving unit 122b and the receiving unit 122a, even if the main direction of the received signal changes depending on the unevenness of the road surface or the object.

[0098] For example, the calculation unit 131 may divide group E into group E1 of received signals Ya calculated based on the superimposed signals received by the receiving unit 122a, and group E2 of received signals Ya calculated based on the superimposed signals received by the receiving unit 122b. The calculation unit 131 may also divide group F into group F1 of received signals Yb calculated based on the superimposed signals received by the receiving unit 122a, and group F2 of received signals Yb calculated based on the superimposed signals received by the receiving unit 122b.

[0099] The calculation unit 131 calculates the signal strength and the difference in signal strength for each of the groups E1, E2, F1, and F2, and the determination unit 132 may determine the presence or absence of the object based on the difference in signal strength of these groups. For example, the determination unit 132 determines that the object exists if at least one of the groups E1, E2, F1, and F2 satisfies the first and second conditions.

[0100] Furthermore, the calculation unit 131 may select the received signal with the higher signal strength from the two received signals of groups E1 and E2 at the same time, and calculate the signal strength and the difference in signal strength for group E'. Similarly, for groups F1 and F2, the received signal with the higher signal strength at the same time may be selected, and the signal strength and the difference in signal strength for group F' may be calculated. The determination unit 132 determines that an object exists if at least one of groups F' and F' satisfies the first and second conditions.

[0101] Furthermore, when generating group E', the calculation unit 131 may combine the two received signals from groups E1 and E2 at the same time. When generating group F', the calculation unit 131 may combine the two received signals from groups F1 and F2 at the same time.

[0102] (Modification 7.4) Figure 13 illustrates the case where sensor units 120a and 120b perform transmission by phase modulation. Transmitting units 121a and 121b can obtain a received signal without interference between electromagnetic wave signals by making the phases of the transmitted electromagnetic wave signals orthogonal.

[0103] The phase of the electromagnetic wave signals transmitted by the transmitting units 121a and 121b is determined by the control unit 133 and commanded to the transmitting units 121a and 121b via the signal generation unit 134.

[0104] For example, in Figure 13, the transmitter 121a transmits an electromagnetic wave signal with phase φ0, and the transmitter 121b transmits an electromagnetic wave signal with phase φ1 that is orthogonal (90 degrees different) to phase φ0. The receiver 122a receives a received signal based on the reflected wave of the electromagnetic wave signal with phase φ0, and the receiver 122b receives a received signal based on the reflected wave of the electromagnetic wave signal with phase φ1. Here, the receiver 122a can extract and receive the signal with phase φ0 during the signal reception process, and the receiver 122b can extract and receive the signal with phase φ1. Therefore, even when the transmitters 121a and 121b transmit electromagnetic wave signals simultaneously, the received signal based on the reflected wave of the electromagnetic wave signal with phase φ0 and the received signal based on the reflected wave of the electromagnetic wave signal with phase φ1 are distinguished and received.

[0105] The operation of the cutting device 160 after receiving the received signal is the same as that of the cutting device 100. Here, the calculation unit 131 may divide the received signal into multiple groups for calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide the received signal into group G, which is based on the reflected wave of an electromagnetic wave signal with phase φ0, and group H, which is based on the reflected wave of an electromagnetic wave signal with phase φ1, and calculate the signal strength and the difference in signal strength. This makes it possible to determine whether or not an object exists at the Y-direction position where the sensor units 120a and 120b are installed, respectively. The determination unit 132 determines that an object exists if at least one of group G and group H satisfies the first and second conditions.

[0106] Furthermore, in the phase modulation method, the receiving units 122a and 122b may receive a received signal with phase φ0 and a received signal with phase φ1. Figure 11 illustrates the case where the receiving units 122a and 122b receive a received signal with phase φ0 and a received signal with phase φ1. During the signal reception processing, the receiving units 122a and 122b can receive the signal with phase φ0 and the signal with phase φ1 separately. This reduces reception errors of the received signal, even if the main direction of the received signal changes due to irregularities in the road surface or the object.

[0107] The calculation unit 131 may further divide the received signals from group G and group B into multiple groups when calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide group G into group G1 of received signals received by the receiving unit 122a and group G2 of received signals received by the receiving unit 122b. The calculation unit 131 may also divide group H into group H1 of received signals received by the receiving unit 122a and group H2 of received signals received by the receiving unit 122b.

[0108] The calculation unit 131 calculates the signal strength and the difference in signal strength for each of the groups G1, G2, H1, and H2, and the determination unit 132 may determine the presence or absence of the object based on the difference in signal strength of these groups. For example, the determination unit 132 determines that the object exists if at least one of the groups G1, G2, H1, and H2 satisfies the first and second conditions.

[0109] Furthermore, the calculation unit 131 may select the received signal with the higher signal strength from the two received signals of groups G1 and G2 at the same time, and calculate the signal strength and the difference in signal strength for group G'. Similarly, the calculation unit 131 may select the received signal with the higher signal strength for groups H1 and H2 at the same time, and calculate the signal strength and the difference in signal strength for group H'. The determination unit 132 determines that an object exists if at least one of groups G' and group H' satisfies the first and second conditions.

[0110] Furthermore, when generating group G', the calculation unit 131 may combine the two received signals from groups G1 and G2 at the same time. When generating group H', the calculation unit 131 may combine the two received signals from groups H1 and H2 at the same time.

[0111] As described above, these modified examples 7 allow for the determination of the presence or absence of an object using multiple sensor units 120. By using multiple sensor units 120, the range in which the presence or absence of an object can be determined can be expanded, and the possibility of failing to recognize an object can be reduced.

[0112] (Variation 8) In this modified example, the sensor unit 120 of Modified Example 7 is configured in multiple units, and vertical polarization and horizontal polarization are used. Figure 15 is a diagram showing the configuration of a cutting device 170 equipped with multiple sensor units 120, namely sensor units 120a, 120b, 120c, and 120d.

[0113] Transmitting units 121a and 121b each transmit a vertically polarized electromagnetic wave signal, and transmitting units 121c and 121d each transmit a horizontally polarized electromagnetic wave signal. Receiving units 122a and 122b each receive a vertically polarized received signal based on the reflected electromagnetic wave signal. Receiving units 122a and 122b each receive a horizontally polarized received signal based on the reflected electromagnetic wave signal.

[0114] The following describes the transmission and reception of electromagnetic wave signals from sensor units 120a and 120c. Sensor units 120b and 120d are the same as sensor units 120a and 120c, so their description is omitted.

[0115] Figure 16 illustrates the case where sensor units 120a and 120c transmit electromagnetic wave signals with different polarizations. By transmitting electromagnetic wave signals with different polarizations, the effects of unevenness can be reduced.

[0116] For example, in Figure 16, the transmitter 121a transmits a vertically polarized electromagnetic wave signal, and the transmitter 121c transmits a horizontally polarized electromagnetic wave signal. The receiver 122a receives a vertically polarized received signal based on the reflected electromagnetic wave signal transmitted by the transmitter 121a. The receiver 122c receives a horizontally polarized received signal based on the reflected electromagnetic wave signal transmitted by the transmitter 121c.

[0117] The operation of the cutting device 170 after receiving the received signal is the same as that of the cutting device 100. Here, the calculation unit 131 may divide the received signal into multiple groups for calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide the received signal into group I of vertically polarized signals and group J of horizontally polarized signals and calculate the signal strength and the difference in signal strength. This improves the accuracy of determining whether or not an object exists. The determination unit 132 determines that an object exists if at least one of group I and group J satisfies the first and second conditions.

[0118] Here, depending on the unevenness of the road surface or the object, the main direction and polarization direction of the received signal may change in part. In this case, the received signal with the changed polarization direction is received by another receiving unit 122. Figure 17 illustrates the case where receiving units 122a and 122c also receive the received signal with the changed polarization direction.

[0119] The receiver 122a receives a vertically polarized received signal based on the reflected wave of the vertically polarized electromagnetic wave signal transmitted by the transmitter 121a, and a received signal that has been changed to vertical polarization by reflection from the horizontally polarized electromagnetic wave signal transmitted by the transmitter 121c. The receiver 122c receives a horizontally polarized received signal based on the reflected wave of the horizontally polarized electromagnetic wave signal transmitted by the transmitter 121c, and a received signal that has been changed to horizontal polarization by reflection from the vertically polarized electromagnetic wave signal transmitted by the transmitter 121a. By receiving signals not only with the receiver 122a but also with the receiver 122c, the effects of unevenness can be reduced, and the number of errors in receiving the received signal can be reduced.

[0120] In this case, since interference may occur between vertically polarized waves or between horizontally polarized waves, the control unit 133 determines the time at which the transmitting units 121a and 121c transmit electromagnetic wave signals, and this time is commanded to the transmitting units 121a and 121c via the signal generation unit 134.

[0121] In Figure 17(a), at time t0, the transmitter 121a transmits a vertically polarized electromagnetic wave signal. The receiver 122a receives a vertically polarized received signal based on the reflected wave of this electromagnetic wave signal, and the receiver 122c receives a received signal that has been changed to horizontal polarization based on the reflected wave of this electromagnetic wave signal. In Figure 17(b), at time t1, the transmitter 121a transmits a horizontally polarized electromagnetic wave signal. The receiver 122c receives a horizontally polarized received signal based on the reflected wave of this electromagnetic wave signal, and the receiver 122a receives a received signal that has been changed to vertical polarization based on the reflected wave of this electromagnetic wave signal.

[0122] Similarly, at time 2n (where n is a non-negative integer), the transmitter 121a transmits an electromagnetic wave signal, and at time 2n+1, the transmitter 121b transmits an electromagnetic wave signal.

[0123] The calculation unit 131 may further divide the vertically polarized received signals, Group I and Group J, into multiple groups when calculating the signal strength and the difference in signal strength. For example, the calculation unit 131 may divide Group I into Group I1 of the received signals at time 2n and Group I2 of the received signals at time 2n+1. The calculation unit 131 may also divide Group J into Group J1 of the received signals at time 2n and Group J2 of the received signals at time 2n+1.

[0124] The calculation unit 131 calculates the signal strength and the difference in signal strength for each of the groups I1, I2, J1, and J2, and the determination unit 132 may determine the presence or absence of the object based on the difference in signal strength of these groups. For example, the determination unit 132 determines that the object exists if at least one of the groups I1, I2, J1, and J2 satisfies the first and second conditions.

[0125] Furthermore, the calculation unit 131 may select the received signal with the higher signal strength from the two received signals of groups I1 and I2 at the same time, and calculate the signal strength and the difference in signal strength for group I'. Similarly, the calculation unit 131 may select the received signal with the higher signal strength for groups J1 and J2 at the same time, and calculate the signal strength and the difference in signal strength for group J'. The determination unit 132 determines that an object exists if at least one of groups I' and group J' satisfies the first and second conditions.

[0126] Furthermore, when generating group I', the calculation unit 131 may combine the two received signals from groups I1 and I2 at the same time. When generating group J', the calculation unit 131 may combine the two received signals from groups J1 and J2 at the same time.

[0127] As described above, these modified examples 8 allow for the determination of the presence or absence of an object using sensor units 120 with different polarizations. By using sensor units 120 with different polarizations, the range in which the presence or absence of an object can be determined can be expanded, and the possibility of failing to recognize an object can be reduced.

[0128] Modifications of this embodiment have been described above. These modifications may be applied in combination. The cutting device 100 (signal processing device 110) of this embodiment transmits electromagnetic wave signals toward the road surface while moving. It receives a received signal based on the reflected waves from the road surface and determines the presence or absence of an object on the road surface based on the received signal. In this way, the risk of overlooking an object on the road surface can be reduced, and object detection can be performed with reduced influence from weather and time of day.

[0129] (Second embodiment) In the second embodiment, the sensor unit 120' transmits an electromagnetic wave signal. The cutting device 200 (signal processing device 110') calculates the angular distribution of the received signal intensity (hereinafter also referred to as the angular distribution of signal intensity) based on the received signal which is based on the reflected wave of this electromagnetic wave signal, and determines the presence or absence of an object on the road surface based on this angular distribution of signal intensity. More specifically, the cutting device 200 calculates the difference in the angular distribution of signal intensity based on the angular distribution of signal intensity, and determines the presence or absence of an object on the road surface based on the difference in the angular distribution of signal intensity.

[0130] This expands the range over which the presence or absence of an object on the road surface can be determined. The components of the cutting device 200 are the same as those of the cutting device 100, except that the sensor unit 120 is replaced with a sensor unit 120'. Examples of sensors 120' include a patch antenna, a horn antenna, a planar antenna, a periodic structure leak wave antenna, and a metamaterial antenna. The sensor unit 120' includes a transmitter 121' and a receiver 122'.

[0131] The operation of the cutting device 200 is the same as that of the cutting device 100 described in Figure 5, except that the signal strength is changed to the angular distribution of the signal strength and the difference in signal strength is changed to the difference in the angular distribution of the signal strength. Figure 18 is a diagram showing the transmission range of the electromagnetic wave signal of the sensor unit 120' and the reception range of the received signal based on the reflected wave in this embodiment. The transmitting unit 121' transmits an electromagnetic wave signal in the width direction (Y direction) of the cutting device 100 within the range of angle θ. The range of angle θ is, for example, the range from angle θ1 to θ2 with respect to the direction perpendicular to the road surface. For example, in Figure 18, an electromagnetic wave signal is transmitted in the range from +40 degrees to -40 degrees with respect to the direction perpendicular to the road surface, and the receiving unit 122' receives a received signal based on the reflected wave of this electromagnetic wave signal.

[0132] The calculation unit 131 calculates the angular distribution of signal strength based on the received signal, with the transmission angle of the electromagnetic wave signal from the transmission unit 121' and the distance from the sensor unit 120' as the axes. Any method can be applied to calculate the angular distribution of signal strength. For example, the calculation unit 131 may perform an angle-by-angle scan using a digital domain array signal processing method using a MIMO radar system (hereinafter, the angle-by-angle scan will also be referred to as angle scanning) and calculate the angular distribution of signal strength. The calculation unit 131 may perform an angle scan using a phased array antenna system, either by transmitting beamforming, which transmits the electromagnetic wave signal at a predetermined angle, or by receiving beamforming, which receives the received signal at a predetermined angle, and calculate the angular distribution of signal strength. The calculation unit 131 may perform an angle scan based on the received signal corresponding to the directional pattern of the antenna of the sensor unit 120', which is switched according to a command from the control unit 133, and calculate the angular distribution of signal strength.

[0133] Figure 19 shows the angular distribution of signal strength in the case of Figure 18 as an example. The Z-axis in Figure 19 is defined by dividing it into sections based on the time from when the transmitter 121' transmits the electromagnetic wave signal until when the receiver 122' receives it, converting this time into distance, and is divided into sections Z1 to Z8. The θ-axis in Figure 19 is defined in sections of 10 degrees from +40 degrees to -40 degrees. The divisions in the Z-axis and θ-axis can be set according to the resolution of the sensor unit 120'. Hereafter, the range defined by the divisions in the Z-axis and θ-axis will also be referred to as an area. Signal strength is shown for each area, and in Figure 19, stronger signal strengths are shown in black. White areas indicate the absence of reflectors of the electromagnetic wave signal.

[0134] In Figure 19, the signal strength is strongest in the area Z=Z5, θ=0 degrees, and decreases in the following order: Z=Z5, θ=±10 degrees, Z=Z6, θ=±20 degrees, Z=Z7, θ=±30 degrees, ±40 degrees. Looking at Figure 18, the areas Z=Z5, θ=0 degrees, Z=Z5, θ=±10 degrees, and Z=Z6, θ=±20 degrees represent received signals reflected by the object, while the area Z=Z7, θ=±30 degrees, ±40 degrees represents received signals reflected by the asphalt road surface.

[0135] Figure 20 shows the angular distribution of signal intensity and the difference in the angular distribution of signal intensity at each time point in a similar case to Figure 3 described in the first embodiment. In the difference in the angular distribution of signal intensity, the larger the absolute value of the difference, the darker the area is shown.

[0136] The calculation unit 131 calculates the angular distribution of signal strength based on the received signal at times t1 to t5, and calculates the difference in the angular distribution of signal strength based on the angular distribution of signal strength. The determination unit 132 generates a flag if the angular distribution of signal strength satisfies a third condition regarding the angular distribution of signal strength. The third condition is that the first condition described in the first embodiment is satisfied in any area of ​​the angular distribution of signal strength. The third condition may also be called the third condition regarding the difference in the angular distribution of signal strength.

[0137] The determination unit 132 determines that an object exists on the road surface if the fourth condition regarding the angular distribution of signal intensity is met, based on the angular distribution of signal intensity within the flag retention period. The fourth condition is that the second condition described in the first embodiment is met in any area of ​​the angular distribution of signal intensity. The fourth condition may also be referred to as the fourth condition regarding the difference in the angular distribution of signal intensity.

[0138] Furthermore, the third condition may be that the first condition is satisfied in a predetermined number of areas in the angular distribution of signal intensity, and the fourth condition may be that the second condition is satisfied in a predetermined number of areas in the angular distribution of signal intensity.

[0139] For example, in Figure 20, the decision unit 132 recognizes that there is an area (outlined by a dashed line) that satisfies the first condition among the difference in the angular distribution of signal intensity at times t1 and t2, and generates a flag as the third condition is met. The decision unit 132 recognizes that there is an area (outlined by a dashed line) that satisfies the fourth condition among the difference in the angular distribution of signal intensity at times t4 and t5, which is within the flag retention period. The decision unit 132 determines that an object exists on the road surface as both the third and fourth conditions are met.

[0140] The cutting apparatus 200 in this embodiment has been described above. The cutting apparatus 200 described in this embodiment is just one example, and various modifications can be implemented and executed. For example, the modifications described in the first embodiment can also be applied to the cutting apparatus 200. The signal intensity in the first embodiment may be read as the angular distribution of the signal intensity, and the difference in the signal intensity may be read as the difference in the angular distribution of the signal intensity. Modifications of this embodiment are described below.

[0141] (Extreme variation 9) In this embodiment, the transmitting unit 121' transmits an electromagnetic wave signal within an angle θ range in the width direction (Y direction) of the cutting device 100. The method of transmitting the electromagnetic wave signal within the angle θ range is arbitrary. For example, a device capable of transmitting electromagnetic wave signals over a wide angle may be used, multiple electromagnetic wave signals may be transmitted from angle θ1 to θ2, or electromagnetic wave signals may be transmitted from angle θ1 to θ2 by changing the frequency of the electromagnetic wave signal according to time. The calculation unit 131 calculates the angle distribution of signal intensity using the method for calculating the angle distribution of signal intensity described in this embodiment.

[0142] The transmitting unit 121' may transmit electromagnetic wave signals within the range of angle θ by transmitting multiple electromagnetic wave signals from angle θ1 to θ2. Multiple antennas are used as the antenna for the sensor unit 120'. For example, the transmitting unit 121' uses a phased array antenna system and transmits electromagnetic wave signals within the range of angle θ by the transmission beamforming described in this embodiment. The transmission interval of the electromagnetic wave signals from angle θ1 to θ2 is made shorter than the time from time tx to tx+1. In this case, the transmission of a series of electromagnetic wave signals from angle θ1 to θ2 is considered to be a transmission at time tx.

[0143] Figure 21 shows an example of a case where the frequency of an electromagnetic wave signal is changed according to time. As the antenna of the sensor unit 120', an antenna is used in which the main direction of the transmitted electromagnetic wave signal depends on the frequency. For example, a periodic structure leaky wave antenna or a metamaterial antenna. In Figure 21, an electromagnetic wave signal with frequency fa is transmitted at time ta, and an electromagnetic wave signal with frequency fb is transmitted at time tb while changing the frequency according to the passage of time. If the electromagnetic wave signal with frequency fa is transmitted at angle θ1 and the electromagnetic wave signal with frequency fb is transmitted at angle θ2, then electromagnetic wave signals can be transmitted within the range of angle θ. Note that the time from time ta to tb is sufficiently small compared to the time from time tx to tx+1, so the series of transmissions from time ta to tb is considered as a transmission at time tx.

[0144] (Variation 10) In this embodiment, it is possible to recognize the length of candidate objects in the width direction (Y direction) of the cutting device 200 from the angular distribution of signal intensity and the difference between the angular distributions of signal intensity. For example, in Figure 20, the determination unit 132 can recognize that there are three areas of candidate objects from the difference in the angular distribution of signal intensity.

[0145] The determination unit 132 may estimate the length of the object in the Y direction based on the angular distribution of signal intensity or the difference in the angular distribution of signal intensity. For example, in Figure 20, the area where the candidate object exists is Z=Z5, θ=±10 degrees, so the determination unit 132 can estimate that the length of the candidate object in the Y direction is the length of an arc of 20 degrees with radius Z5. Based on the estimated length, the determination unit 132 may determine at least one of generating a flag and determining whether or not the object exists.

[0146] For example, suppose the memory unit 105 holds information representing the maximum length Lmax that determines an object to exist. The determination unit 132 estimates the length of the object in the Y direction and compares it with the length Lmax. If the estimated length exceeds Lmax, the determination unit 132 does not generate a flag, determining that it is not an object, and does not determine that an object exists. In this way, the accuracy of determining the presence or absence of an object can be improved.

[0147] Modifications of this embodiment have been described above. The cutting device 200 (signal processing device 110') of this embodiment transmits electromagnetic wave signals toward the road surface from an angle θ1 to θ2 while moving. The cutting device 200 receives a received signal based on the reflected wave from the road surface, calculates the angular distribution of signal intensity based on the received signal, and determines the presence or absence of an object on the road surface. In this way, the range over which the presence or absence of an object on the road surface can be determined can be expanded.

[0148] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims. [Explanation of symbols]

[0149] 100: Cutting equipment 101: Body section 102: Drive unit 103: Conveyor section 104: Cutting part 105: Storage section 110, 110': Signal processing device 120, 120a, 120b, 120c, 120d, 120': Sensor section 121, 121a, 121b, 121c, 121': Transmitter 122, 122a, 122b, 122c, 122': Receiver 130: Processing Unit 131: Calculation Section 132: Decision Section 133: Control Unit 134: Signal generation unit 140: Notification Department 150: Cutting equipment 160: Cutting equipment 200: Cutting equipment

Claims

1. A transmitting unit that transmits multiple electromagnetic wave signals toward the road surface, A receiving unit that receives multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals, A processing unit determines to stop cutting the road surface if, among the multiple differences in signal intensity of received signals at adjacent transmission times based on the aforementioned multiple received signals, the first difference and the second difference satisfy the conditions regarding the signal intensity of the reflected wave based on the object. A notification unit that notifies the cessation of cutting the road surface, A signal processing device comprising, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal strength determined based on the object, the second difference satisfies the second condition for signal strength determined based on the object, within the time that the signal processing device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. Signal processing device.

2. The first and second conditions are conditions with the sign reversed. The signal processing apparatus according to claim 1.

3. The transmitting unit includes a first transmitting unit that transmits a plurality of first electromagnetic wave signals and a second transmitting unit that transmits a plurality of second electromagnetic wave signals at different times than the first transmitting unit. The plurality of first electromagnetic wave signals and the plurality of second electromagnetic wave signals are included in the plurality of electromagnetic wave signals. The receiving unit receives a plurality of first received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of second received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. The plurality of first received signals and the plurality of second received signals are included in the plurality of received signals. The signal processing apparatus according to claim 1 or 2.

4. The aforementioned processing unit, If at least one of the differences in the first signal strength of a plurality of first received signals at adjacent transmission times, or the differences in the second signal strength of a plurality of second received signals at adjacent transmission times, satisfies the conditions relating to the signal strength of the reflected wave based on the object, then the cutting of the road surface is stopped. The signal processing apparatus according to claim 3.

5. The transmitting unit includes a first transmitting unit that transmits a plurality of first electromagnetic wave signals of a first frequency and a second transmitting unit that transmits a plurality of second electromagnetic wave signals of a second frequency. The receiving unit includes a first receiving unit and a second receiving unit. The first receiving unit receives at least one of a plurality of first received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of second received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. The second receiving unit receives at least one of a plurality of third received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of fourth received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. At least one of the plurality of first received signals and the plurality of second received signals, and at least one of the plurality of third received signals and the plurality of fourth received signals are included in the plurality of received signals. The signal processing apparatus according to claim 1 or 2.

6. The transmitting unit includes a first transmitting unit that transmits a plurality of first electromagnetic wave signals having a first code, and a second transmitting unit that, in response to the transmission of the plurality of first electromagnetic wave signals, transmits at least one of a plurality of second electromagnetic wave signals having the first code and a plurality of third electromagnetic wave signals having the second code with the first code inverted. The receiving unit receives a plurality of first superimposed signals obtained by superimposing the first electromagnetic wave signal and the second electromagnetic wave signal, and a plurality of second superimposed signals obtained by superimposing the first electromagnetic wave signal and the third electromagnetic wave signal. The processing unit calculates the plurality of received signals based on the plurality of first superimposed signals and the plurality of second superimposed signals. The signal processing apparatus according to claim 1 or 2.

7. The processing unit calculates a plurality of first received signals and a plurality of second received signals included in the received signal based on the plurality of first superimposed signals and the plurality of second superimposed signals, If at least one of the differences in the first signal strength of a plurality of first received signals at adjacent transmission times, or the differences in the second signal strength of a plurality of second received signals at adjacent transmission times, satisfies the conditions relating to the signal strength of the reflected wave based on the object, then the cutting of the road surface is stopped. The signal processing apparatus according to claim 6.

8. The transmitting unit includes a first transmitting unit that transmits a plurality of first electromagnetic wave signals of a first phase and a second transmitting unit that transmits a plurality of second electromagnetic wave signals of a second phase orthogonal to the first phase. The receiving unit includes a first receiving unit and a second receiving unit. The first receiving unit receives at least one of a plurality of first received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of second received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. The second receiving unit receives at least one of a plurality of third received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of fourth received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. At least one of the plurality of first received signals and the plurality of second received signals, and at least one of the plurality of third received signals and the plurality of fourth received signals are included in the plurality of received signals. The signal processing apparatus according to claim 1 or 2.

9. The transmitting unit includes a first transmitting unit that transmits a plurality of first electromagnetic wave signals with vertical polarization and a second transmitting unit that transmits a plurality of second electromagnetic wave signals with horizontal polarization. The receiving unit includes a first receiving unit that receives vertically polarized waves and a second receiving unit that receives horizontally polarized waves. The first receiving unit receives at least one of a plurality of first received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of second received signals based on the reflected waves of the plurality of second electromagnetic wave signals on the road surface. The second receiving unit receives at least one of a plurality of third received signals based on the reflected waves of the plurality of first electromagnetic wave signals on the road surface and a plurality of fourth received signals based on the reflected waves of the second electromagnetic wave signals on the road surface. At least one of the plurality of first received signals and the plurality of second received signals, and at least one of the plurality of third received signals and the plurality of fourth received signals are included in the plurality of received signals. The signal processing apparatus according to claim 1 or 2.

10. The processing unit determines to stop cutting the road surface if at least one of the differences in the first signal strength of a plurality of first received signals and a plurality of third received signals at adjacent transmission times, or the differences in the second signal strength of a plurality of second received signals and a plurality of fourth received signals at adjacent transmission times, satisfies the conditions relating to the signal strength of the reflected wave based on the object. The signal processing apparatus according to any one of claims 5, 8, and 9.

11. A transmitting unit that transmits multiple electromagnetic wave signals toward the road surface at angles from the first to the second angle, A receiving unit that receives multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals, A processing unit determines to stop cutting the road surface if, based on the plurality of received signals, the distance from the receiving unit and the angular distribution of the signal intensity of the received signals from the first angle to the second angle, the first difference and the second difference among the multiple differences in signal intensity in the angular distribution of adjacent transmission times satisfy the conditions relating to the signal intensity of the reflected wave based on the object, A notification unit that notifies the cessation of cutting the road surface, A signal processing device comprising, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal strength determined based on the object, the second difference satisfies the second condition for signal strength determined based on the object, within the time that the signal processing device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. Signal processing device.

12. The first and second conditions are conditions with the sign reversed. The signal processing device according to claim 11.

13. The processing unit commands the angle of the transmitting unit so that the main direction of the plurality of electromagnetic wave signals is substantially perpendicular to the road surface, and Based on the inclination angle of the road surface, at least one of the following is performed: the angle of the receiving unit is commanded so that the receiving surface of the receiving unit is substantially perpendicular to the principal direction of the plurality of received signals. The signal processing apparatus according to any one of claims 1 to 12.

14. The cutting section that cuts the road surface, A transmitting unit that transmits multiple electromagnetic wave signals toward the road surface, A receiving unit that receives multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals, A processing unit determines to stop cutting the road surface if, among the multiple differences in signal intensity of received signals at adjacent transmission times based on the aforementioned multiple received signals, the first difference and the second difference satisfy the conditions regarding the signal intensity of the reflected wave based on the object. A notification unit that notifies the cessation of cutting the road surface, A cutting device comprising, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal intensity determined based on the object, the second difference satisfies the second condition for signal intensity determined based on the object, within the time that the cutting device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. cutting equipment.

15. The cutting section that cuts the road surface, A transmitting unit that transmits multiple electromagnetic wave signals toward the road surface at angles from the first to the second angle, A receiving unit that receives multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals, A processing unit determines to stop cutting the road surface if, based on the plurality of received signals, the first and second differences among the plurality of differences in signal intensity in the angle distribution of adjacent transmission times satisfy the conditions relating to the signal intensity of the reflected wave based on the object, the distance from the receiving unit and the plurality of angular distributions of the signal intensity of the received signal from the first angle to the second angle, and A notification unit that notifies the cessation of cutting the road surface, A cutting device comprising, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal intensity determined based on the object, the second difference satisfies the second condition for signal intensity determined based on the object, within the time that the cutting device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. cutting equipment.

16. It transmits multiple electromagnetic wave signals toward the road surface, Multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals are received, If, among the multiple differences in signal intensity of received signals at adjacent transmission times based on the aforementioned multiple received signals, the first and second differences satisfy the conditions regarding the signal intensity of the reflected wave based on the object, then the cutting of the road surface is stopped. A method performed by a signal processing device to notify the cessation of cutting the road surface, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal strength determined based on the object, the second difference satisfies the second condition for signal strength determined based on the object, within the time that the signal processing device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. method.

17. Multiple electromagnetic wave signals are transmitted toward the road surface at angles from the first to the second angle. Multiple received signals based on reflected waves corresponding to the multiple electromagnetic wave signals are received, Based on the plurality of received signals, if, in the distance from the receiving unit and the plurality of angular distributions of the signal intensity of the received signals from the first angle to the second angle, the first and second differences among the plurality of differences in signal intensity in the angular distributions of adjacent transmission times satisfy the conditions regarding the signal intensity of the reflected wave based on the object, then the cutting of the road surface is stopped. A method performed by a signal processing device to notify the cessation of cutting the road surface, If the above conditions are met, This is the case where, within one hour after the first difference satisfies the first condition for signal strength determined based on the object, the second difference satisfies the second condition for signal strength determined based on the object, within the time that the signal processing device moves a distance based on the length of the object, The distance based on the length of the object is smaller than the distance from the receiving unit to the cutting unit that performs the cutting of the road surface. method.

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