Laser radar device

Abstract

To achieve further improvement in detection accuracy of an object by a laser radar device.SOLUTION: A laser radar device 10 comprises a rotation block 41 that can change an irradiation direction of laser light. In the rotation block 41, an encoder disc 61 is anchored so as to be rotatable integrally with the rotation block 41. In the encoder disc 61, a plurality of slits is arrayed along an outer rim of the encoder disc. The rotation block 41 rotates, and the slit sequentially passes a photointerrupter 71, thereby an encoder signal composed of a pulse string corresponding to each slit is output to a control unit 12. The control unit 12 is configured to: grasp an average cycle of a pulse in a partial section of a prescribed circulation, of the encoder signals outputted at the prescribed circulation under a situation where a rotation velocity of the rotation block 41 stands at a target rotation velocity; and diagnose whether the rotation block is in a state of normally outputting the encoder signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laser radar device. [Background technology]

[0002] A scanning laser radar device comprises an irradiating unit that sequentially irradiates laser light at predetermined angles and a light receiving unit that receives the reflected light of the laser light, and is configured to determine whether an object such as a person or a vehicle is located within a monitored area based on the amount of light received by the light receiving unit, etc. Some laser radar devices of this type are provided with a rotating change unit (e.g., a mirror) that changes the direction of laser light irradiation, and are configured so that the laser light is irradiated onto the monitored area while this change unit is constantly rotating (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication No. 2789741 Summary of the Invention [Problem to be solved by the invention]

[0004] In a laser radar device having the above-described rotary type changing unit, even when the changing unit is rotating steadily, the rotational speed of the changing unit may change due to various factors. Here, by using a rotary encoder to identify the rotational position of the changing unit and irradiating laser light according to the identified rotational position, specifically by mounting a rotating body (e.g., an encoder disk or a magnetic drum) on which detectable portions (e.g., slits or magnets) are arranged at every predetermined angle so as to rotate integrally with the changing unit, identifying the rotational position of the changing unit from an encoder signal consisting of a pulse train corresponding to each detectable portion, and irradiating laser light according to the identified rotational position, it is possible to suppress variations in the irradiation of laser light at every predetermined angle due to the influence of changes in rotational speed.

[0005] However, in a configuration in which the timing of laser light irradiation is determined from the encoder signal (pulse), the following new concerns arise. Specifically, if the assembly error of the rotating body becomes large or if the rotating body is deformed, such as distorted, these influences may cause variations in the encoder signal (specifically, pulse width, pulse period, etc.). Furthermore, if the play of the rotating shaft of the change unit increases due to aging or other reasons, the encoder signal (specifically, pulse width, pulse period, etc.) may be disturbed. If the spacing of the laser light changes due to the disturbance of the encoder signal, a bias in the direction of laser light irradiation, i.e., differences in density, will occur.

[0006] The effect of the difference in density of the laser beam is small at positions relatively close to the laser radar device, but becomes more pronounced the farther away from the laser radar device. In other words, if a monitoring area is set at a position far away from the laser radar device, there is a concern that the difference in density of the laser beam will cause the laser beam to not hit objects located in the monitoring area properly, increasing the possibility of delays in detection of the object or an oversight of detection. Furthermore, even if the monitoring area is set at a position relatively close to the laser radar device, there is a concern that the difference in density of the laser beam will increase the possibility of delays in detection or an oversight of detection if small objects are assumed to be detected.

[0007] As described above, there is still room for improvement in the configuration of the laser radar device in terms of accurately detecting distant objects and small objects.

[0008] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to further improve the accuracy of object detection by a laser radar device. [Means for solving the problem]

[0009] The following describes means for solving the above problems.

[0010] First means: A laser radar device comprising an irradiation unit that irradiates a monitoring area with laser light and a light receiving unit that receives reflected light, which is the laser light reflected by an object, and that determines whether an object that reflected the laser light is located in the monitoring area based on the reception status of the reflected light by the light receiving unit, the irradiation unit includes a change unit that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder that includes a rotating body that can rotate integrally with the changing unit in the predetermined scanning direction and that is formed so that a plurality of detectable parts are lined up in the predetermined scanning direction, and a detecting unit that can detect the detectable parts that are located at predetermined detection positions, and that outputs an encoder signal consisting of a pulse train corresponding to each of the detectable parts as the detectable parts pass the predetermined detection positions in order as the rotating body rotates, the detection portions are formed at predetermined angular intervals in the predetermined scanning direction, and the laser light is periodically irradiated by controlling the output of the laser light based on the encoder signal input from the rotary encoder; The device is equipped with a diagnostic unit that grasps diagnostic information, which is information indicating the length of a specific waveform output in a partial section of the encoder signal output in a specified revolution under conditions in which the rotation speed of the rotating body is the target rotation speed, and diagnoses whether the encoder signal is in a state in which it can be output normally based on the grasped diagnostic information.

[0011] For example, if the center of the rotating body (e.g., encoder disk or magnetic drum) and the center of rotation of the change unit are misaligned due to work variations when installing the rotary encoder, the pulse output pattern of part of the pulse train that makes up the encoder signal for one revolution may deviate from the basic pattern. If this deviation becomes large, the output encoder signal will become an abnormal signal with a pulse width, pulse period, etc. that is outside the expected range. Such abnormal signals may also occur when there is significant play in the rotating shaft of the change unit due to bearing wear, etc., or when distortion or other deformation occurs in the rotating body.

[0012] If a laser beam is output based on the above-described abnormal encoder signal, the laser beam, which is supposed to be emitted at a predetermined angle, may be emitted at shorter or longer intervals than expected. In particular, when the laser beam is emitted at longer intervals than expected, there is a concern that the laser beam may not hit the object properly, resulting in delayed detection of the object or an increased likelihood of the object being overlooked, compared to when no such change occurs. This is undesirable because it reduces the accuracy of object detection. Such an effect is particularly noticeable when accurately detecting distant objects or small objects.

[0013] In this regard, the configuration of this feature takes note of the occurrence of changes in the pulses and implements the following measures. Specifically, diagnostic information indicating the length of a specific waveform is obtained from the encoder signal output during a predetermined rotation when the rotation speed of the rotating body is at the target rotation speed. Then, based on the obtained diagnostic information, it is diagnosed whether the encoder signal can be output normally. By determining when laser light cannot be properly emitted in this manner, it is possible to take measures such as prompting the user to inspect the laser radar device. For these reasons, delays in object detection can be suppressed, contributing to improved object detection accuracy by the laser radar device. This is advantageous for accurately detecting distant objects or small objects. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a laser radar device according to a first embodiment. [Figure 2] Schematic diagram showing a rotating block. [Figure 3] FIG. [Figure 4] FIG. 2 is a block diagram showing the electrical configuration of the laser radar device. [Figure 5] 5A and 5B are schematic diagrams showing the relationship between a pulse train constituting an encoder signal and the output timing of a laser beam. [Figure 6] FIG. 4 is a schematic diagram showing an assembled state of the encoder disk. [Figure 7] 10A and 10B are schematic diagrams comparing laser light irradiation modes. [Figure 8] 10 is a flowchart showing a diagnostic data preparation process. [Figure 9] FIG. 1 is a schematic diagram showing a flow of data update. [Figure 10] 10 is a flowchart showing a diagnostic process. [Figure 11] 4 is a timing chart showing a flow of diagnosis. [Figure 12] FIG. 10 is a schematic diagram showing how a target section is shifted in the second embodiment. [Figure 13] FIG. 11 is a schematic diagram showing the relationship between an average value and a diagnosis result in the third embodiment. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] FIG. [Figure 17] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] First Embodiment A first embodiment will be described below with reference to the drawings. This embodiment is embodied as a laser radar device for area monitoring.

[0016] The laser radar device 10 shown in Figure 1 comprises an optical mechanism 11 that emits pulsed laser light (hereinafter referred to as laser light) at an irradiation angle set at predetermined angles (0.25° in this embodiment) and receives the reflected light of the laser light, a control unit 12 (specifically, an FPGA) that controls the optical mechanism 11, and a housing 13 that houses the optical mechanism 11 and the control unit 12, and is installed so that the laser light irradiation port formed in the housing 13 faces the monitoring area DE.

[0017] The optical mechanism 11 is composed of a light-emitting unit 11a, a light-receiving unit 11b, and an optical path forming unit 11c. The light-emitting unit 11a includes a laser diode 21 that intermittently outputs laser light in accordance with the control of the control unit 12, and a collimating lens 22 that is disposed on the optical path of the laser light output from the laser diode 21. The laser diode 21 and the collimating lens 22 are both attached to the back wall of the housing 13 so that their optical axes are horizontal. The laser light output from the laser diode 21 is converted into parallel light by passing through the collimating lens 22, and then travels toward the optical path forming unit 11c disposed in the center of the housing 13.

[0018] The optical path forming unit 11c has a first mirror 25 fixed to the housing 13 and a rotating block 41 on which a second mirror 42 is mounted and which faces the first mirror 25. The first mirror 25 is formed with a reflecting surface 25a which is inclined obliquely (facing obliquely downward) with respect to the optical axis of the light emitting unit 11a, and the laser light output from the light emitting unit 11a is guided to a reflecting surface 42a of the second mirror 42 by the reflecting surface 25a.

[0019] The reflecting surface 42a of the second mirror 42 is inclined (facing diagonally upward) relative to the direction in which the mirrors 25, 42 are arranged side by side (the up-down direction), and the laser light reflected by the first mirror 25 is reflected again by the second mirror 42 and directed to the irradiation port of the housing 13. A transparent window panel 15 is fitted into the irradiation port, and the laser light directed to the irradiation port passes through the window panel 15 and is irradiated onto the monitoring area DE.

[0020] Here, the rotating block 41 will be further explained with reference to Figure 2. The rotating block 41 has a cylindrical holder 43 that supports the second mirror 42. A disk-shaped base portion 44 is formed at the lower end of the holder 43, and an output shaft 52 of a motor 51 is fixed to a fixing portion 45 formed at the center of the base portion 44. The motor 51 is connected to the control unit 12, and when the motor 51 is driven by the control unit 12, the rotating block 41 (second mirror 42) rotates (orbits) together with the output shaft 52.

[0021] The central axis CL1, which is the rotation center of the rotating block 41, extends in the vertical direction and its direction coincides with the direction of the laser light incident from the first mirror 25 to the second mirror 42. An incident position P1 of the laser light from the first mirror 25 to the second mirror 42 is defined to be a position on the central axis CL1 of the reflecting surface 42a. The rotating block 41 rotates horizontally around the central axis CL1, changing the orientation of the second mirror 42, thereby realizing a configuration in which the irradiation direction of the laser light can be changed. That is, in this embodiment, the scanning direction of the laser light from the laser radar device 10 is the horizontal direction, specifically, the rotation direction around the central axis CL1 (the circumferential direction of a circle centered on the central axis CL1). Incidentally, in this embodiment, the rotating block 41 and the motor 51 constitute a change unit 40 corresponding to a “changer,” and the change unit 40 and the light-emitting unit 11a correspond to an “irradiator.”

[0022] When an object OB is located in a monitoring area DE, and laser light is irradiated from the laser radar device 10 onto the monitoring area DE and hits the object OB, part of the laser light (reflected light) reflected by the object OB may reach the laser radar device 10. For convenience, in Fig. 1, the laser light reaching the object OB from the laser radar device 10 is denoted by the symbol L1, and the part of the reflected light reflected by the object OB that reaches the light receiving unit 11b is denoted by the symbol L2.

[0023] 1, the light receiving unit 11b is disposed above the optical path forming unit 11c (the ceiling of the housing 13), and the reflected light is guided to the light receiving unit 11b by the second mirror 42. Specifically, the light receiving unit 11b includes a photodiode 31 attached to the ceiling of the housing 13, a condenser lens 32 (light collecting unit) disposed between the photodiode 31 and the second mirror 42, specifically above the first mirror 25, and a filter 33 disposed between the condenser lens 32 and the photodiode 31, and the reflected light from the second mirror 42 is guided to the photodiode 31 via the condenser lens 32 and the filter 33. The filter 33 is a wavelength-selective filter that transmits only light of a specific wavelength corresponding to the reflected light and blocks other light, and transmits the reflected light and removes light other than the reflected light on the optical path from the optical path forming unit 11c to the photodiode 31.

[0024] The laser radar device 10 shown in this embodiment is equipped with a photoelectric rotary encoder 60 as a rotational position detection means for identifying the rotational position of the rotation block 41, i.e., the orientation of the second mirror 42. Here, the rotary encoder 60 and its related configuration will be described with reference to FIGS. 2 and 3.

[0025] 2, the rotary encoder 60 is composed of a thin, plate-like encoder disk 61 and a photointerrupter 71, which will be described later. The encoder disk 61 is provided below the holder 43 and is arranged so as to overlap the base portion 44 of the holder 43. The encoder disk 61 is circular and is attached so that its central axis CL2 coincides with the central axis CL1 of the rotation block 41 (see FIG. 3).

[0026] Specifically, a plurality of screw holes 46 are formed in the base portion 44 of the holder 43 in a portion overlapping with the encoder disk 61, and a plurality of communication holes 66 that communicate with the screw holes 46 are formed in the encoder disk 61. Screws 69 are inserted into the communication holes 66 and threadedly engaged with the respective screw holes 46, thereby integrating the encoder disk 61 and the holder 43. An opening 62 is formed in the center of the encoder disk 61, and this opening 62 prevents interference between the encoder disk 61 and the motor 51.

[0027] The diameter (outer diameter) of the encoder disk 61 is larger than the diameter of the base portion 44 of the holder 43, and when the encoder disk 61 is attached to the base portion 44, an outer edge portion ME of the encoder disk 61 is configured to protrude from the base portion 44. This outer edge portion ME has a number of slits 63 (corresponding to "detected portions") formed therein, extending in a direction perpendicular to the central axis CL2. More specifically, the many slits 63 are arranged at equal intervals (equal angles) in the circumferential direction of a circle centered on the central axis CL2, thereby forming an annular scale centered on the central axis CL2. Note that when the encoder disk 61 is properly attached and the central axes CL1 and CL2 are aligned, the slits 63 can also be said to be aligned in the scanning direction (rotation direction).

[0028] The photointerrupter 71 has a recessed insertion portion into which the outer edge portion ME of the encoder disk 61 is inserted, and a light-emitting element 72 and a light-receiving element 73 are arranged in this insertion portion so as to face each other vertically. As the encoder disk 61 rotates, each slit 63 formed in the outer edge portion ME passes through a detection position DP (corresponding to a "predetermined detection position") between the light-emitting element 72 and the light-receiving element 73 in order.

[0029] When the slits 63 are located at the detection position DP, light from the light-emitting element 72 reaches the light-receiving element 73 through the slits 63, and the encoder signal output from the rotary encoder 60 becomes HI level. On the other hand, when a solid portion 64 between the slits 63 is located at the detection position DP, the light from the light-emitting element 72 is blocked by the solid portion 64, and the encoder signal output from the rotary encoder 60 becomes LOW level. In other words, as the slits 63 pass through the detection position DP in order as the encoder disk 61 rotates, an encoder signal consisting of a pulse train corresponding to each slit 63 is output. The photointerrupter 71 is connected to the control unit 12, and the control unit 12 can grasp the rotational position of the rotating block 41 based on the encoder signal from the photointerrupter 71.

[0030] The outer edge ME of the encoder disk 61 has a slit-free portion (blank portion 65) where the slits 63 are not formed, which is wider than the portion where the slits 63 are formed at equal intervals. The control unit 12 can detect (identify) the blank portion 65 from the portion where the pulse missing occurs in the encoder signal, and when the control unit 12 detects the blank portion 65, it determines that the rotation position of the rotating block 41 is at the origin position. Furthermore, it can calculate the rotation period of the rotating block 41 (motor 51) from the period at which the pulse missing occurs in the encoder signal.

[0031] Next, a supplementary explanation will be given of the electrical configuration of the laser radar device 10 with reference to Fig. 4. The motor driver IC 51b of the motor 51 and the laser diode 21 are connected to the output side of the control unit 12 of the laser radar device 10, and the photodiode 31 and the photointerrupter 71 of the rotary encoder 60 are connected to the input side of the control unit 12. The control unit 12 has a function of controlling the drive of the motor 51 (motor control unit 82), a function of controlling the light emission of the laser diode 21 (laser control unit 83), and a function of determining whether an object OB is located in the monitoring area DE (object determination unit 84), and the motor control unit 82, laser control unit 83, and object determination unit 84 constitute an area monitoring unit 81.

[0032] The motor control unit 82 performs feedback using PID control based on the encoder signal from the rotary encoder 60, and controls the rotation speed of the motor main body 51a via the motor driver IC 51b. This control makes it possible to maintain the rotation speed of the rotation block 41 at a preset rotation speed (hereinafter also referred to as target rotation speed).

[0033] The laser control unit 83 starts outputting laser light in response to rotational position information acquired from the rotary encoder 60, specifically, the rising edge of a pulse in the encoder signal, and stops outputting the laser light when a predetermined output time has elapsed since the start of output (see FIG. 5). This light emission control causes the laser radar device 10 to output laser light to the monitoring area DE at each irradiation angle set for each predetermined angle. Note that this output time is shorter than the pulse width when the rotation speed of the rotating block 41 is the target rotation speed, i.e., the time from the rising edge to the falling edge of the pulse.

[0034] The object determination unit 84 determines whether the object OB is located in the monitoring area DE based on the rotational position information and the state of reception of reflected light by the photointerrupter 71. In addition, an alarm unit consisting of a speaker, lamp, etc. is connected to the control unit 12, and when an object OB located within the monitoring area DE is detected, for example, an alarm indicating this is issued by the alarm unit.

[0035] In the laser radar device 10 shown in this embodiment, the inner diameter of the communication holes 66 formed in the encoder disk 61 is larger than the screw holes 46, taking into consideration manufacturing errors in the holder 43 and the encoder disk 61. This configuration allows for smooth alignment and installation of the holder 43 and the encoder disk 61 during the manufacturing process, etc., and prevents the encoder disk 61 from being installed too forcefully. As described above, the encoder disk 61 has a thin plate thickness, which makes it prone to deformation such as distortion. Therefore, preventing excessive installation is preferable in terms of reducing the chances of deformation such as distortion occurring in the encoder disk 61.

[0036] However, in such a configuration, the following new concern arises when outputting laser light at regular intervals based on the encoder signal. This concern will be explained below with reference to Figures 6 and 7. Figures 6(a) and 7(a) illustrate a case where the encoder disk 61 is attached in an appropriate position, while Figures 6(b) and 7(b) illustrate a case where the encoder disk 61 is not attached in an appropriate position. Note that in Figure 6, some of the slits 63 are distinguished as slits PA to PD for the sake of convenience.

[0037] In the example shown in FIG. 6(a), the encoder disk 61 is mounted in an appropriate position, and the central axis CL1 of the rotating block 41 and the central axis CL2 of the encoder disk 61 coincide with each other. When the encoder disk 61 and the rotating block 41 rotate integrally around the central axis CL1, the rotation angle when moving from one slit PA located on the left side of the central axis CL1 to the adjacent slit PB is a predetermined angle α, and the rotation angle when moving from one slit PC located on the right side of the central axis CL1 to the adjacent slit PD is also a predetermined angle α. When the encoder disk 61 is mounted in an appropriate position as described above, the pulse period of the encoder signal output during steady rotation at the target rotation speed is constant over the entire section (excluding the missing pulses described above) (see FIG. 7(a1)). Furthermore, the laser beams irradiated based on the encoder signal are also equally spaced (see FIG. 7(a2)). Note that the output pattern of the pulse train with a constant pulse period corresponds to the "basic pattern."

[0038] 6(b), the encoder disk 61 is not attached in an appropriate position, and the central axis CL1 of the rotating block 41 is misaligned with the central axis CL2 of the encoder disk 61. Specifically, the encoder disk 61 is attached misaligned to the right with respect to the rotating block 41. When the encoder disk 61 and the rotating block 41 rotate together around the central axis CL1, the rotation angle when moving from one slit PA located on the left side of the central axis CL1 to the adjacent slit PB is an angle α1 that is larger than the predetermined angle α, and the rotation angle when moving from one slit PC located on the right side of the central axis CL1 to the adjacent slit PD is an angle α2 that is smaller than the predetermined angle α.

[0039] In this way, when the encoder disk 61 is not attached in the correct position, the pulse period of the encoder signal output under conditions of steady rotation at the target rotation speed will not be constant (see FIG. 7(b1)). That is, in parts where the actual angle is larger than the predetermined angle α, the pulse period will be long and the pulses will be sparse, and in parts where the actual angle is smaller than the predetermined angle α, the pulse period will be short and the pulses will be dense. In other words, the encoder signal corresponding to one scanning cycle (one rotation) will have parts where the pulses are sparse and parts where they are dense. The laser beam groups irradiated based on the encoder signal will not be spaced equally, and differences in sparseness will occur (see FIG. 7(b2)).

[0040] In particular, when the laser light is emitted at longer intervals than expected and the laser light group becomes sparse, there is a concern that the laser light may not hit the object OB properly, which may delay the detection of the object OB or make it more likely that the object OB will be missed, compared to when there is no such change (see, for example, FIG. 7(b2)). Such concerns become stronger at positions farther away than at positions closer to the laser radar device 10, and stronger when the object OB is small than when it is large. In other words, this hinders the accurate detection of distant objects or small objects.

[0041] Incidentally, abnormal encoder signals in which the pulse width, pulse period, etc. are outside the expected range can occur not only when the encoder disk 61 is installed in a position that is different from the appropriate position, but also when the bearing 53 (see Figure 3) for the output shaft 52 provided on the motor body 51a wears out, causing significant shaft wobble, or when the encoder disk 61 is distorted or deformed.

[0042] One of the features of the control unit 12 of the laser radar device 10 shown in this embodiment is that it has a diagnostic function (diagnostic unit 85: see FIG. 4) that diagnoses whether the encoder signal is in a state where it can be output normally. More specifically, one of the features is that it is configured to grasp (extract) diagnostic data, which is data indicating the length of a specific waveform, from the encoder signal output under conditions where the rotation speed of the rotating block 41 is equal to the target rotation speed, and to diagnose whether the encoder signal is in a state where it can be output normally based on the grasped diagnostic data. Below, the configuration related to this diagnosis, specifically the diagnostic data preparation process and diagnostic process executed by the control unit 12 as part of periodic processing, will be described.

[0043] As shown in the flowchart of Fig. 8, in the diagnostic data preparation process, first, in step S101, it is determined whether the diagnostic data preparation conditions are met. In this embodiment, the diagnosis is performed periodically (for example, daily), and if the following various conditions are met: (1) an object OB is not detected, (2) no notification is being made that the encoder signal cannot be output normally, and (3) the diagnosis start time has arrived, a positive determination is made in step S101 and the process proceeds to step S102. Note that if a negative determination is made in step S101, the preparation process ends immediately.

[0044] In step S102, it is determined whether the rotation speed of the rotating block 41 is at the target rotation speed (a speed at which one rotation = 35 msec in this embodiment). If the determination in step S102 is negative, the preparation process is terminated. If the determination in step S102 is positive, the process proceeds to step S103, where it is determined whether the timing is the timing at which a pulse rises in the encoder signal, i.e., the timing at which the encoder signal becomes HI level. If the determination in step S103 is positive, the pulse period data that is the source of the diagnostic data is secured. Specifically, first, in step S104, a shift process is performed on the data of the past pulse period, and in step S105, data of the current pulse period, for example, data indicating the time from the rise of the previous pulse to the rise of the current pulse, is saved.

[0045] 9, the memory unit 86 is provided with a first area AD1 to a fourth area AD4 as memory areas capable of storing data of past pulse periods. In the process of step S104, the data stored in the fourth area AD4 is erased, and the data stored in the first area AD1 to the third area AD3 is shifted sequentially toward the lower areas. Then, in the process of step S105, the data of the current pulse period is saved in the first area AD1.

[0046] Returning to the explanation of FIG. 8, after the data has been secured, or if it is determined in step S103 that it is not the timing for a pulse to rise, the process proceeds to step S106. In step S106, it is determined whether it is time to calculate the average pulse period (hereinafter also referred to as the average value). In this embodiment, the average pulse period is calculated multiple times (three times in this embodiment) during one scanning cycle (one rotation). The first time, a positive determination is made in step S106 when a predetermined waiting time (10 msec in this embodiment) has elapsed since passing the origin position, and thereafter, a positive determination is made in step S106 when a predetermined waiting time has elapsed since the previous calculation timing. If it is not the calculation timing, a negative determination is made in step S106, and the preparation process ends thereafter.

[0047] If the determination in step S106 is affirmative, the process proceeds to step S107. In step S107, an average pulse period is calculated from the pulse period data stored in the first area AD1 to the fourth area AD4. The calculated average value is then stored in an average value storage area of ​​the storage unit 86. In the following step S108, it is determined whether the number of stored average values ​​has reached a specified number (three in this embodiment). If the number has not reached the specified number, the preparation process ends. If the number has reached the specified number, the process proceeds to step S109, where a diagnostic flag is set and the preparation process ends.

[0048] Next, the diagnostic processing will be described with reference to the flowchart in Fig. 10. In the diagnostic processing, first, in step S201, it is determined whether the diagnostic flag is set. If the diagnostic flag is not set, the diagnostic processing ends. If the diagnostic flag is set, the processing proceeds to step S202, where it is determined whether all of the calculated average values ​​are within a preset reference range. If they are within the reference range, a comparison process is performed between the average values. Specifically, first, in step S203, the differences (absolute values) between the three average values ​​are calculated. Thereafter, in step S204, it is determined whether the difference between the average values ​​is smaller than a reference value (corresponding to a "threshold value").

[0049] If a positive judgment is made in both step S202 and step S204, that is, if each average value is within the reference range and the difference between the average values ​​is smaller than the reference value, it is diagnosed that the encoder signal can be output normally, and after erasing various diagnostic data and flags in step S205, this diagnostic processing is terminated.

[0050] On the other hand, if a negative determination is made in either step S202 or step S204, i.e., if any of the average values ​​is outside the reference range or any of the differences between the average values ​​is greater than the reference value, it is determined that the encoder signal cannot be output normally, i.e., the encoder signal is abnormal, and abnormality processing is executed in step S206. In the abnormality processing, the notification unit such as the speaker or lamp described above is controlled to start a notification urging inspection of the laser radar device 10. Thereafter, various diagnostic data and flags are erased in step S205, and this diagnostic processing ends.

[0051] In this embodiment, if a negative determination is made in step S202 or step S204, the abnormality process in step S206 is immediately executed, but the present invention is not limited to this. For example, the diagnosis may be repeated over multiple scanning cycles, and if a negative determination is made in step S202 or step S204 and the number of repetitions reaches a predetermined number, the abnormality process in step S206 may be executed.

[0052] Next, the flow of diagnosis will be described with reference to the timing chart in Fig. 11. Note that Fig. 11 shows an encoder signal equivalent to one scan cycle (one rotation) output under conditions in which the rotation speed of the rotating block 41 is the target rotation speed, but for convenience, the number of pulses constituting the encoder signal is shown to be less than the actual number of pulses.

[0053] At time ta0, when the rotation position of the rotating block 41 is at the origin position, a new scanning cycle begins in time with the rise of the first pulse, and irradiation of the monitoring area DE with laser light begins. At time ta1, when a predetermined waiting time has elapsed since time ta0, the average period of the pulses in this scanning cycle is first calculated. At this point, data on the most recent four pulse periods is stored in the first area AD1 to the fourth area AD4 of the memory unit 86, and an average value AVE1 is calculated from this data and saved.

[0054] At time ta3, a predetermined waiting time after time ta1, the second calculation of the average pulse period for this scanning cycle is performed. At this time, the data stored in the first area AD1 to the fourth area AD4 of the memory unit 86 has been updated with the data for the most recent four pulse periods, and the average value AVE2 is calculated from this data and saved.

[0055] Here, the laser light projection section in this scanning cycle ends at timing ta2, which is before timing ta3. However, the encoder disk 61 shown in this embodiment has slits 63 arranged around the entire circumference except for blank portions 65, and the encoder signal is configured to switch between two values, HI level and LOW level, in both the light projection section and the non-light projection section. In other words, the pulse train continues until the end of the scanning cycle even after the laser light projection section has passed.

[0056] At time ta4, a predetermined waiting time after time ta3, the average pulse period for this scanning cycle is calculated for the third time. At this time, the data stored in the first area AD1 to the fourth area AD4 of the memory unit 86 has been updated to the data for the most recent four pulse periods, and the average value AVE3 is calculated from this data and saved.

[0057] In the example shown in FIG. 11, the pulses are coarse from timing ta0 to timing ta1, which is reflected in the average value AVE1. In other words, the average value AVE1 is longer than the average value in the normal pattern described above. The pulses are dense from timing ta3 to timing ta4, which is reflected in the average value AVE3. In other words, the average value AVE3 is shorter than the average value in the normal pattern described above. Note that the pulse output pattern is normal from timing ta1 to timing ta3, and the relationship between the average value AVE2, which reflects this, and the other average values ​​AVE1 and AVE3 is average value AVE3 < average value AVE2 < average value AVE1.

[0058] At timing ta4, the three average values ​​AVE1 to AVE3, which are diagnostic data for this scanning cycle, are available, and diagnosis is performed based on these average values ​​AVE1 to AVE3.

[0059] While the average value AVE2 is within the above-mentioned reference range, the average values ​​AVE1 and AVE3 are outside the reference range. Furthermore, while the difference between the average values ​​AVE1 and AVE2 and the difference between the average values ​​AVE2 and AVE3 are smaller than the reference values, the difference between the average values ​​AVE1 and AVE3 exceeds the reference value. The diagnosis in this scanning cycle determines that the encoder signal cannot be output normally, and an abnormality alert is initiated.

[0060] According to the first embodiment described above in detail, the following excellent effects are achieved.

[0061] If the encoder disk 61 is not installed in the correct position, if the encoder disk 61 is distorted or deformed, or if the rotating shaft of the rotating block 41 is loose, it is highly likely that some of the output encoder signals will be affected. Therefore, as shown in this embodiment, the average pulse period is calculated from some of the encoder signals output during a predetermined rotation when the rotation speed of the rotating block 41 is equal to the target rotation speed. Based on the calculated average, it is determined whether the encoder signals can be output normally. This allows for prompt detection of a situation in which laser light cannot be emitted properly. Early detection reduces the chance of pulse density variations, thereby suppressing delays in object OB detection and contributing to improved object OB detection accuracy by the laser radar device 10. This is advantageous for accurately detecting distant objects or small objects.

[0062] The size and position of the slits 63 on the encoder disk 61 may vary slightly due to manufacturing errors. While such errors do not have a significant impact within the dimensional tolerances, it is preferable to consider the impact of such errors in order to improve diagnostic accuracy. In this regard, by calculating an average value from multiple pulse periods as shown in this embodiment, it is possible to mitigate the impact of manufacturing errors on diagnostic results, even if the manufacturing errors significantly affect the data for some pulse periods. Furthermore, if the laser radar device 10 is subjected to vibration or impact, the encoder signal may be momentarily disturbed. If a single pulse period is used as diagnostic data, such disturbances are likely to have a strong impact on the diagnostic results. In this regard, using the average value of multiple pulse periods as diagnostic data, as shown in this embodiment, is preferable in terms of suppressing the impact of disturbances. Note that if a manufacturing error reduces the distance between a single slit 63 and one of the adjacent slits 63, the distance between the first slit 63 and the other slits 63 may increase. Therefore, for pulse trains with repeated peaks and valleys, setting the diagnostic data equal to the average pulse period can more easily mitigate the impact of the bias in the position of the slits 63, as described above.

[0063] In this embodiment, the average value of the pulse period is calculated for each of a plurality of different sections, and these average values ​​are compared. With this configuration, even if the influence on each average value is small, it can be prevented from being overlooked in cases where the influence on the encoder disk 61 as a whole is large.

[0064] Comparing average values ​​obtained in the same scanning cycle makes it easier to align the conditions when obtaining each average value. Aligning the conditions to obtain each piece of diagnostic information to be compared is advantageous in reducing the influence (disturbance) of external forces such as wind and vibrations, thereby improving the reliability of the diagnostic function.

[0065] The pulses that are the basis for calculating the average value are narrowed down to a portion of the pulse group corresponding to one scan cycle, and other pulses are not included. As the parameter of data for calculating the average value becomes larger, the influence of pulse variations tends to be overshadowed, but as shown in this embodiment, by deliberately separating target pulses from non-target pulses, it is possible to prevent the influence of pulse variations from being overshadowed, contributing to the rapid discovery of abnormalities in the encoder signal.

[0066] <Second embodiment> One of the features of this embodiment is that it is designed to further strengthen the diagnostic function shown in the first embodiment. Below, the characteristic configuration of this embodiment will be described, focusing on the differences from the first embodiment, with reference to Fig. 12. Note that this embodiment is also similar to the first embodiment in that the average pulse period is calculated for multiple sections during one scan cycle (one rotation).

[0067] In the first embodiment, the section in which the average value is first calculated in each scanning cycle (hereinafter also referred to as the target section) is determined based on the origin position, i.e., the predetermined waiting time is not counted across scanning cycles. In this configuration, the same section is targeted for diagnosis each time.

[0068] In contrast to this, in this embodiment, the diagnosis is performed in multiple consecutive scan cycles (specifically, 18 scan cycles), and a predetermined waiting time is counted across the scan cycles during that time. In other words, when the predetermined waiting time has been counted from the timing of calculating the last average value in the previous scan cycle, the count continues even when the next scan cycle is started during the count.

[0069] The predetermined waiting time (11 msec) shown in this embodiment is a non-integer multiple of the time required for one scanning cycle (35 msec) when the rotation speed of the rotating block 41 is the target rotation speed. Therefore, with each scanning cycle, the section for calculating the average value shifts slightly in the circumferential direction of the circle centered on the central axis CL2, specifically in the direction opposite to the scanning direction.

[0070] 12, in the Nth scanning cycle (Nth rotation) after the start of diagnosis, average values ​​AVEa1 to AVEa3 are calculated for target sections Sa1 to Sa3. While a predetermined waiting time is being counted from the third calculation timing in this scanning cycle, the rotating block 41 returns to the origin position and moves on to the next scanning cycle. In this case, the above-mentioned deviation occurs by the difference (2 msec) between the product (33 msec) of the predetermined waiting time (11 msec) multiplied by the number of calculations (3 times) and the time required for one scanning cycle (35 msec).

[0071] Specifically, in the (N+1)th scanning cycle (N+1th rotation), the first calculation timing occurs when a predetermined wait time has elapsed since the third calculation timing in the Nth scanning cycle, and an average value AVEb1 is calculated for a target section Sb1 that includes the most recent M pulse periods going back from that calculation timing. In other words, the time from returning to the origin position to the first calculation timing is shorter by the above-mentioned difference compared to the Nth scanning cycle. The second calculation timing occurs when a predetermined wait time has elapsed since the first calculation timing in this scanning cycle, and an average value AVEb2 is calculated for a target section Sb2. The third calculation timing occurs when a predetermined wait time has elapsed since the second calculation timing, and an average value AVEb3 is calculated for a target section Sb3.

[0072] While counting the predetermined waiting time from the third calculation timing in this scan cycle, the system returns to the origin position and moves on to the next scan cycle. In this case, the above-mentioned deviation occurs again. Specifically, in the (N+2)th scan cycle (N+2 rotation), the first calculation timing occurs when the predetermined waiting time has elapsed since the third calculation timing in the (N+1)th scan cycle, and the average value AVEc1 is calculated for the target section Sc1, which includes the most recent M pulse periods going back from that calculation timing. In other words, the time from returning to the origin position to the first calculation timing is shorter than that in the (N+1)th scan cycle by the above-mentioned difference. The second calculation timing occurs when the predetermined waiting time has elapsed since the first calculation timing in this scan cycle, and the average value AVEc2 is calculated for the target section Sc2. The third calculation timing occurs when the predetermined waiting time has elapsed since the second calculation timing, and the average value AVEc3 is calculated for the target section Sc3.

[0073] Depending on the timing, one of the target sections may include at least a portion of the blank section 65. The time during which the encoder signal is at a low level in the blank section 65 is longer than in the flesh section 64, and this may be mixed in with the diagnostic information, reducing diagnostic accuracy. Therefore, in this embodiment, measurement of the pulse period is disabled when passing through the blank section 65, and the measurement results are not used to calculate the average value. Note that in this embodiment, each target section is longer than the blank section 65, and even if the target section includes the entire blank section 65, it is specified that data for at least multiple pulse periods is secured for that target section.

[0074] Furthermore, the shift amounts of the target sections are specified so that the target sections in the preceding and succeeding scanning cycles partially overlap, i.e., so that the slit 63 for measuring the pulse period partially overlaps in the preceding and succeeding scanning cycles. Specifically, the first target section in the preceding scanning cycle partially overlaps with the first target section in the following scanning cycle, the second target section in the preceding scanning cycle partially overlaps with the second target section in the following scanning cycle, and the third target section in the preceding scanning cycle partially overlaps with the third target section in the following scanning cycle. For example, in the example shown in FIG. 12 , the first target section Sa1 in the Nth scanning cycle partially overlaps with the first target section Sb1 in the (N+1)th scanning cycle, and the first target section Sb1 in the (N+1)th scanning cycle partially overlaps with the first target section Sc1 in the (N+2)th scanning cycle.

[0075] In this way, by expanding the target section by shifting it slightly with each scan cycle, it is possible to prevent the above-mentioned abnormality from being overlooked. In particular, by intentionally overlapping the target section when shifting it, the effect of preventing oversight can be more effectively achieved.

[0076] In this embodiment, the relationship between the period that is the calculation timing and the time required for one scan cycle when the target rotation speed is achieved is devised, so that the target section is automatically shifted as the scan cycle progresses. This makes it possible to easily realize a configuration for shifting the target section. Note that a configuration in which the time required for one scan cycle when the target rotation speed is not an integer multiple of the period that is the calculation timing is preferable in order to cover the entire scan cycle while gradually shifting the target section.

[0077] <Third embodiment> The laser radar device 10 is used in a variety of environments. For this reason, the possibility of being subjected to vibrations, shocks, and the like cannot be denied. If a misdiagnosis of an "abnormality" occurs when a disturbance caused by vibrations, shocks, or the like affects the encoder signal even though the encoder signal is normally able to be output, there is a concern that the diagnostic function and, ultimately, the reliability of the laser radar device 10 will be reduced. One of the features of this embodiment is that it is designed to improve disturbance resistance in diagnosis. The following describes this design, focusing on the differences from the first and second embodiments.

[0078] In this embodiment, too, average values ​​AVE1 to AVE3 of the pulse period are calculated in three sections in one scan cycle, and these calculated average values ​​AVE1 to AVE3 are compared with a reference range, and the difference between the average values ​​AVE1 to AVE3 is compared with a reference value.

[0079] FIG. 13 shows patterns in which a diagnosis of "normal" and a diagnosis of "abnormal" are made in this embodiment. When all of the average values ​​AVE1 to AVE3 of the pulse periods are within the reference range and the differences between these average values ​​AVE1 to AVE3 are smaller than the reference value, the diagnosis result is "normal." On the other hand, when any of the average values ​​AVE1 to AVE3 are outside the reference range or when any of the differences between these average values ​​AVE1 to AVE3 are smaller than the reference value, the diagnosis result is "abnormal." Furthermore, when all of the average values ​​AVE1 to AVE3 are outside the reference range and the differences between these average values ​​AVE1 to AVE3 are smaller than the reference value, the diagnosis result is "abnormal." These patterns are the same as those in the first embodiment, etc.

[0080] On the other hand, even if all of the average values ​​AVE1 to AVE3 are outside the reference range, if the differences between these average values ​​AVE1 to AVE3 are smaller than the reference value, the diagnostic result is not determined to be "abnormal" but to be "normal." Because the rotating block 41 (encoder disk 61) rotates at high speed, if the encoder signal is affected by a disturbance, the average values ​​AVE1 to AVE3 calculated over a short period (e.g., the same scanning cycle) are likely to reflect this influence. On the other hand, if the encoder disk 61 is misaligned, if the encoder disk 61 is distorted or deformed, or if there is significant play in the rotating shaft, it is unlikely that this influence will affect all of the average values ​​AVE1 to AVE3. In particular, this possibility is further reduced by moving the target sections farther apart. In other words, if all of the average values ​​AVE1 to AVE3 are outside the reference range, it is highly likely that disturbances are the cause. If the differences between these average values ​​AVE1 to AVE3 are all smaller than the reference value, the possibility that disturbance is the cause becomes even higher. Therefore, in such cases, even if the value is numerically abnormal, by diagnosing it as "normal" (not diagnosing it as "abnormal"), even if the encoder signal is accidentally disturbed when it can be output normally, it is possible to prevent frequent occurrence of abnormality notifications, etc. This contributes to improving resistance to disturbances.

[0081] When calculating the difference between the average values ​​AVE1 to AVE3, the configuration for diagnosis may be partially simplified by calculating the difference between the maximum and minimum values ​​of the average values ​​AVE1 to AVE3 rather than calculating the difference between each combination of the average values ​​AVE1 to AVE3. In such a configuration, even if all of the average values ​​AVE1 to AVE3 are outside the reference range, if the difference between the maximum and minimum values ​​of the average values ​​AVE1 to AVE3 is smaller than the reference value, the diagnosis result may not be "abnormal" but may be "normal."

[0082] Furthermore, in this embodiment, even if all of the average values ​​AVE1 to AVE3 are outside the reference range, if the differences between these average values ​​AVE1 to AVE3 are all smaller than the reference value, the "diagnosis result" is determined to be "normal." However, this may be modified as follows: That is, the "diagnosis result" may be determined to be "abnormal," but the abnormality process (S206) triggered by the diagnosis result may not be executed, i.e., an abnormality notification or the like may be avoided.

[0083] <Other embodiments> The present invention is not limited to the contents of the above-described embodiments, and may be implemented, for example, as follows. Each of the following configurations may be applied individually to the above-described embodiments, or a part or all of the configurations may be combined and applied to the above-described embodiments. It is also possible to arbitrarily combine all or a part of the various configurations shown in the above-described embodiments. In this case, it is preferable that the technical significance (effects to be exhibited) of each of the configurations to be combined is ensured.

[0084] In the above embodiments, the pulse period (more specifically, the average period) of the encoder signal is grasped, and based on the grasped pulse period, a diagnosis is made as to whether the encoder signal is in a state where it can be output normally. However, the specific configuration is arbitrary as long as a portion of the encoder signal for one scanning cycle (one rotation of the rotating block 41) is extracted and used as "diagnostic information." For example, the ON time of one pulse (the time from the rise to the fall of the pulse: pulse width) may be grasped as "diagnostic information," and the above diagnosis may be made based on the grasped ON time. Alternatively, the OFF time of one pulse (the time from the fall to the rise of the pulse) may be grasped as "diagnostic information," and the above diagnosis may be made based on the grasped OFF time.

[0085] In the above embodiments, the configuration is such that whether the encoder signal is being output normally is diagnosed based on the average value of the pulse period. However, instead of this, it is also possible to configure the configuration such that the diagnosis is performed based on the pulse period of a single pulse.

[0086] In the above embodiments, the configuration is such that both the average pulse period is compared with a reference value and these average periods are compared with each other, but it is also possible to configure the configuration to perform only one of these two types of comparison.

[0087] It is also possible to configure the collection of pulse period data in the target section 1 to be divided into multiple scanning cycles. For example, the target section 1 may be divided into multiple small sections, and pulse period data in each small section may be collected over multiple scanning cycles. In this case, once data collection of pulse period data in each small section has been completed, the average pulse period in the target section 1 may be calculated from the data.

[0088] In the above embodiments, when it is time to calculate the average value of the pulse period, the average value is calculated from the pulse period data stored before that time, but this is not limited to this.When it is time to calculate the average value of the pulse period, the average value may be calculated from the pulse period data stored thereafter.

[0089] The calculation period for the average pulse period may be a variable value that varies depending on the rotation speed of the rotation block 41 (the rotation speed of the motor 51). For example, if a relatively slow first rotation speed and a relatively fast second rotation speed are set as target rotation speeds for the rotation block 41, the calculation period for the second rotation speed may be shorter than the calculation period for the first rotation speed. More specifically, the calculation period may be changed in proportion to the target rotation speed.

[0090] In each of the above embodiments, the target section can be either a light-projection section in which laser light is projected onto the monitoring area DE or a non-light-projection section in which laser light is not projected onto the monitoring area DE. However, considering that the impact of non-light-projection sections is small even if there is variation in the density of the laser light groups, the non-light-projection section may not be a target section.

[0091] In the second embodiment, the target sections in the preceding and following scanning cycles are partially overlapped, but it is also possible to configure the target sections not to overlap. For example, as shown in Fig. 14, in the second scanning cycle (second rotation), the first section Sb1 is located between the first section Sa1 and the second section Sa2 in the first scanning cycle (first rotation), the second section Sb2 is located between the second section Sa2 and the third section Sa3, and the third section Sb3 is located between the third section Sa3 and the first section Sa1. In the third scanning cycle (third rotation), the first section Sc1 is located between the first section Sb1 and the second section Sb2 in the second scanning cycle (second rotation), the second section Sc2 is located between the second section Sb2 and the third section Sb3, and the third section Sc3 is located between the third section Sb3 and the first section Sb1.

[0092] In the second embodiment, the target section is shifted for each scanning cycle, but the specific configuration for shifting the target section may be changed arbitrarily.

[0093] (1) A configuration may be adopted in which the start timing of the target section is determined, and the waiting time from the origin position until the target section begins may be extended or shortened with each scan cycle. For example, as shown in Fig. 15, time may be measured from the origin position at tc0, and the target section (first section Sa1) may begin at tc1, which is the first waiting time TX1 from tc0, during the first rotation after the start of diagnosis; the target section (first section Sb1) may begin at tc2, which is the second waiting time TX2 longer than the first waiting time TX1, during the second rotation; and the target section (first section Sc1) may begin at tc3, which is the third waiting time TX3 longer than the second waiting time TX2, during the third rotation.

[0094] (2) As shown in Fig. 16(a), one scanning cycle may be divided into multiple sections SA to SJ, and the section to be set as the target section in each scanning cycle may be determined by lottery from among the multiple sections SA to SJ. In this case, the section set in the previous lottery may be excluded from the setting candidates in the subsequent lottery, thereby realizing a configuration in which the target section is shifted for each scanning cycle.

[0095] (3) As shown in Fig. 16(a), one scanning cycle may be divided into multiple sections SA to SB, and a map (see Fig. 16(b)) may be stored that defines the order in which the multiple sections SA to SJ should be set as target sections, and the target section may be set for each scanning cycle by referring to the map. In this case, it is preferable to create a map that avoids resetting the same section until the multiple sections SA to SJ have been completed.

[0096] In the above embodiments, non-target intervals (non-extraction intervals) are interposed between target intervals (extraction intervals). However, these non-target intervals can be omitted and adjacent target intervals can be continuous. For example, as shown in FIG. 17 , one scanning cycle (one rotation) can be divided into multiple consecutive target intervals S1-S3. During one scanning cycle, the average value AVE1 of the pulse period in target interval S1, the average value AVE2 of the pulse period in target interval S2, and the average value AVE3 of the pulse period in target interval S3 can be calculated, and diagnosis can be performed based on these average values ​​AVE1-AVE3. However, in such a configuration, the number of pulse periods to be sampled increases, making partial changes in the pulse period less noticeable. Furthermore, the increased number of samples can easily strain the storage capacity of the memory unit 86 and increase the control load. Therefore, as shown in the first embodiment, there is technical significance in deliberately setting up non-target sections, and as shown in the second embodiment, a practically preferable configuration can be realized by covering the non-target sections in one scanning cycle with other scanning cycles.

[0097] 6, the encoder disk 61 may be mounted with its central axis CL2 offset from the central axis CL1 of the rotating block 41. In this case, there may be areas on either side of the center of the encoder disk 61 where the pulse period or pulse width is short, and areas where the pulse period or pulse width is long. In light of this, by setting the target sections so that they face each other across the central axes CL1 and CL2, the effect of this offset will be significantly reflected in the difference when comparing average values.

[0098] In each of the above embodiments, the above diagnosis is performed while the laser radar device 10 is monitoring the monitoring area DE. However, instead of or in addition to this, it is also possible to perform the above diagnosis when the monitoring area DE is not being monitored.

[0099] In each of the above embodiments, the control unit 12 of the laser radar device 10 is configured to diagnose whether the encoder signal is being output normally, but it is also possible to configure the diagnosis to be performed by an inspection device installed in the manufacturing process (e.g., inspection process) of the laser radar device 10 or the rotary encoder 60. Note that the rotary encoder 60 may be provided with a control device for the rotary encoder 60, and the above diagnosis may be performed by the control device.

[0100] A magnetic rotary encoder may be used in place of the photoelectric rotary encoder 60 shown in each of the above embodiments.

[0101] The configurations relating to the diagnosis of the encoder signal shown in the above embodiments can also be applied to devices other than the laser radar device 10 (for example, automobiles and robots).

[0102] <Inventions extracted from the above embodiments> The following describes the features of the inventions extracted from the above embodiments, while indicating, as necessary, their effects, etc. Note that, for ease of understanding, the corresponding configurations in the above embodiments are indicated in parentheses as appropriate, but the invention is not limited to the specific configurations indicated in parentheses.

[0103] Feature 1: A laser radar device (laser radar device 10) that includes an irradiation unit (laser diode 21 and change unit 40) that irradiates a monitoring area (monitoring area DE) with laser light, and a light receiving unit (photodiode 31) that receives reflected light, which is the laser light reflected by an object (object OB), and that determines whether the object that reflected the laser light is located in the monitoring area based on the light receiving state (received light amount, etc.) of the reflected light by the light receiving unit, the irradiation unit includes a change unit (rotation block 41) that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder (rotary encoder 60) that is rotatable integrally with the changing unit in the predetermined scanning direction and has a rotating body (encoder disk 61) on which a plurality of detectable parts (e.g., slits 63) are arranged in the predetermined scanning direction, and a detecting unit (photointerrupter 71) that can detect the detectable parts located at predetermined detection positions (detection positions DP), and outputs an encoder signal consisting of a pulse train corresponding to each of the detectable parts as the detectable parts pass the predetermined detection positions in sequence as the rotating body rotates; The laser beam is periodically irradiated by performing output control (for example, ON / OFF control) of the laser beam based on each pulse of the encoder signal input from the rotary encoder, A laser radar device comprising a diagnostic unit (diagnostic unit 85 in control unit 12) that grasps diagnostic information (such as a pulse period or pulse width) that indicates the length of a specific waveform output in a partial section of a predetermined revolution of the encoder signal output in a situation where the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signal is in a state where it can be output normally based on the grasped diagnostic information.

[0104] For example, if the center of the rotating body (e.g., encoder disk or magnetic drum) and the center of rotation of the change unit are misaligned due to work variations when installing the rotary encoder, the pulse output pattern of part of the pulse train that makes up the encoder signal for one revolution may deviate from the basic pattern. If this deviation becomes large, the output encoder signal will become an abnormal signal with a pulse width, pulse period, etc. that is outside the expected range. Such abnormal signals may also occur when there is significant play in the rotating shaft of the change unit due to bearing wear, etc., or when distortion or other deformation occurs in the rotating body.

[0105] If a laser beam is output based on an abnormal encoder signal such as that described above, the laser beam may be emitted at shorter or longer intervals than expected. In particular, if the laser beam is emitted at longer intervals than expected, there is a concern that the laser beam may not hit the object properly, resulting in delayed detection of the object or an increased likelihood of the object being overlooked, compared to when no such change occurs. This is undesirable because it reduces the accuracy of object detection. This is particularly detrimental to the accurate detection of distant objects or small objects.

[0106] In this regard, the configuration described above focuses on the occurrence of changes in pulses, and obtains diagnostic information indicating the length of a specific waveform from the encoder signal output during a predetermined revolution when the rotational speed of the rotor is at the target rotational speed. By diagnosing whether the encoder signal can be output normally based on this diagnostic information, it is possible to quickly discover a situation in which laser light cannot be emitted properly. This makes it possible to take measures such as prompting the user to inspect the laser radar device. For these reasons, delays in object detection can be suppressed, contributing to improved object detection accuracy by the laser radar device. This is advantageous for accurately detecting distant objects or small objects.

[0107] Feature 2: A laser radar device (laser radar device 10) that includes an irradiation unit (laser diode 21 and change unit 40) that irradiates a monitoring area (monitoring area DE) with laser light, and a light receiving unit (photodiode 31) that receives reflected light, which is the laser light reflected by an object (object OB), and that determines whether the object that reflected the laser light is located in the monitoring area based on the light receiving state (received light amount, etc.) of the reflected light by the light receiving unit, the irradiation unit includes a change unit (rotation block 41) that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder (rotary encoder 60) that includes a rotating body (encoder disk 61) that is rotatable integrally with the changing unit in the predetermined scanning direction and that has a plurality of detectable portions (e.g., slits 63) aligned in the predetermined scanning direction, and a detecting unit (photointerrupter 71) that can detect the detectable portions located at predetermined detection positions (detection positions DP), and that outputs an encoder signal consisting of a pulse train corresponding to each of the detectable portions as the detectable portions pass the predetermined detection positions in sequence as the rotating body rotates; the detection portions are formed at predetermined angular intervals (e.g., 0.25°) in the predetermined scanning direction, and the laser light is periodically irradiated by performing output control (e.g., ON / OFF control) of the laser light based on the encoder signal input from the rotary encoder; A laser radar device comprising a diagnostic unit (diagnostic unit 85 in control unit 12) that grasps diagnostic information (such as a pulse period or pulse width) that indicates the length of a specific waveform output in a partial section of a predetermined revolution of the encoder signal output in a situation where the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signal is in a state where it can be output normally based on the grasped diagnostic information.

[0108] For example, if the center of the rotating body (e.g., encoder disk or magnetic drum) and the center of rotation of the change unit are misaligned due to work variations when installing the rotary encoder, the pulse output pattern of part of the pulse train that makes up the encoder signal for one revolution may deviate from the basic pattern. If this deviation becomes large, the output encoder signal will become an abnormal signal with a pulse width, pulse period, etc. that is outside the expected range. Such abnormal signals may also occur when there is significant play in the rotating shaft of the change unit due to bearing wear, etc., or when distortion or other deformation occurs in the rotating body.

[0109] If laser light is output based on the above-described abnormal encoder signal, the laser light that is supposed to be emitted at a predetermined angle may be emitted at shorter or longer intervals than expected. In particular, when the laser light is emitted at longer intervals than expected, there is a concern that the laser light may not hit the object properly, compared to when there is no such change, which may result in delayed detection of the object or an increased likelihood of the object being missed. This is undesirable because it reduces the accuracy of object detection. In particular, it hinders the accurate detection of distant objects or small objects.

[0110] In this regard, the configuration described above focuses on the occurrence of changes in pulses, and obtains diagnostic information indicating the length of a specific waveform from the encoder signal output during a predetermined revolution when the rotational speed of the rotor is at the target rotational speed. By diagnosing whether the encoder signal can be output normally based on this diagnostic information, it is possible to quickly discover a situation in which laser light cannot be emitted properly. This makes it possible to take measures such as prompting the user to inspect the laser radar device. For these reasons, delays in object detection can be suppressed, contributing to improved object detection accuracy by the laser radar device. This is advantageous for accurately detecting distant objects or small objects.

[0111] The "information indicating the length of a specific waveform (diagnostic information)" shown in Features 1 and 2 may be, for example, the time from a rising edge of the encoder signal to the next rising edge or the time from a falling edge of the encoder signal to the next falling edge, i.e., the pulse period of the encoder signal, the time from a rising edge of the encoder signal to the falling edge (pulse ON time or pulse width), or the time from a falling edge of the encoder signal to the rising edge (pulse OFF time).

[0112] Incidentally, the configuration of the "diagnostic unit" shown in Features 1 and 2 can also be changed to "grasp diagnostic information (such as a pulse period or pulse width) that indicates the length of a specific waveform that is output in a specific section of a scanning cycle in the encoder signal that is output at a specific revolution under conditions in which the rotational speed of the rotating body is a target rotational speed, and diagnose whether the encoder signal is in a state in which it is being output normally, based on the grasped diagnostic information" or "grasp diagnostic information (such as a pulse period or pulse width) that indicates the length of a specific portion that is part of the encoder signal that corresponds to one scanning cycle that is output under conditions in which the rotational speed of the rotating body is a target rotational speed, and diagnose whether the encoder signal is in a state in which it is being output normally, based on the grasped diagnostic information."

[0113] Feature 3: The length of the section is defined to include a plurality of the specific waveforms; 3. The laser radar device according to feature 2, wherein the diagnostic information is information indicating an average value of lengths of the plurality of specific waveforms in the section.

[0114] With respect to rotating bodies, there is a possibility that the size and position of the detection part may vary slightly due to manufacturing errors. While such errors do not have a significant impact if they are within the dimensional tolerance range, there is technical significance in suppressing the effect of such errors in improving diagnostic accuracy. In this regard, by adopting a configuration in which the lengths of multiple specific waveforms are averaged, as shown in this feature, the effect of such errors on the diagnostic results can be suitably mitigated.

[0115] Feature 4: The specific waveform is a waveform corresponding to one pulse period, the length of the section is defined to include a plurality of the specific waveforms; the diagnostic information is an average value of the pulse period in the predetermined section, 2. The laser radar device according to feature 1, wherein the diagnosing unit diagnoses whether the encoder signal is being output normally based on the average value.

[0116] With respect to rotating bodies, there is a possibility that the size and position of the detection part may vary slightly due to manufacturing errors. While such errors do not have a significant impact if they are within the dimensional tolerance range, there is technical significance in suppressing the effect of such errors in improving diagnostic accuracy. In this regard, by adopting a configuration that averages the pulse period, as shown in this feature, the effect of such errors on the diagnostic results can be suitably mitigated.

[0117] Furthermore, if a manufacturing error causes the distance between one detectable part and one of the adjacent detectable parts to become small, the distance between the other detectable part and the other detectable part may become large. In other words, for a pulse train with repeated peaks and valleys, when calculating the average value from multiple specific waveforms, the diagnostic information can be set to the average value of the pulse periods assuming that the specific waveforms include both peaks and valleys, which makes it easier to mitigate the effects of bias in the positions of the detectable parts as described above.

[0118] Feature 5: The laser radar device according to any one of Features 2 to 4, wherein the diagnostic unit grasps the diagnostic information for each of the different sections, and diagnoses whether the encoder signal is being output normally based on a comparison result between the grasped diagnostic information.

[0119] When the irradiation unit is rotating at the target rotation speed, diagnostic information for each of the above different sections is grasped, and diagnosis is performed based on the results of comparing these diagnostic information, thereby suppressing the effects (disturbances) of external forces such as wind and vibrations, thereby contributing to improving the reliability of the diagnostic function.

[0120] Feature 6: The laser radar device according to any one of Features 2 to 4, wherein the diagnostic unit grasps the diagnostic information for each of a plurality of different sections for the encoder signal input during one revolution of the rotating body, and diagnoses whether the encoder signal is in a state where it is normally output based on a comparison result between the grasped diagnostic information.

[0121] Comparing diagnostic information acquired in the same cycle makes it easier to align the conditions when acquiring the diagnostic information. Acquiring each piece of diagnostic information to be compared under the same conditions is preferable for achieving the effect described in Feature 5.

[0122] Feature 7: The different sections are target sections to be identified by the diagnosis unit; The laser radar device according to feature 4 or 5, wherein a non-target section that is not to be grasped by the diagnosing unit is defined to be interposed between the target sections.

[0123] When the parameter of information for calculating the average value becomes large, the influence of pulse variations becomes more easily lost. In this regard, by deliberately setting up non-target sections as shown in this feature, it is possible to prevent the influence of pulse variations from being lost, contributing to the rapid discovery of abnormalities in the encoder signal.

[0124] Feature 8. The different sections include a first section and a second section; 8. The laser radar device according to any one of features 5 to 7, wherein the first section and the second section are set to face each other across the rotation center of the rotating body.

[0125] The center of the rotating body may be installed so that it is offset from the center of rotation of the irradiation unit. In this case, there may be areas on either side of the center of the rotating body where the average period or pulse width is short, and areas where the average period or pulse width is long. By including these areas in the comparison, the differences become more pronounced. This is preferable for improving diagnostic accuracy.

[0126] Feature 9: The laser radar device according to any one of Features 2 to 4, wherein the diagnostic unit compares the determined diagnostic information with a preset reference range, and diagnoses whether the encoder signal is being output normally based on the comparison result.

[0127] As shown by this feature, if the diagnostic information is compared with the reference range, it can be easily diagnosed whether the encoder signal is being output normally.

[0128] Feature 10: The laser radar device according to any one of Features 1 to 3, wherein the diagnosing unit grasps the diagnostic information in each of the different sections, compares the grasped diagnostic information with each other and with a preset threshold, and diagnoses that the encoder signal is in a state where it is normally output when a difference between the grasped diagnostic information is smaller than the threshold and the grasped diagnostic information is all within the reference range, and diagnoses that the encoder signal is not in a state where it is normally output when a difference between the grasped diagnostic information is larger than the threshold or when any of the grasped diagnostic information is outside the reference range.

[0129] As shown by this feature, if the diagnostic information is not only compared with the reference range but also compared with other diagnostic information, it can contribute to further improving the accuracy of diagnosis.

[0130] Feature 11. The diagnostic unit is configured to execute abnormality processing when it diagnoses that the encoder signal is not in a normal output state, The laser radar device according to feature 10 is configured such that, if the difference between the acquired diagnostic information is smaller than the threshold value, and if all of the acquired diagnostic information is outside the reference range, the abnormality processing is not performed.

[0131] For example, if the rotation speed of the irradiation unit temporarily changes due to the influence of external forces such as wind or vibration, the difference between the diagnostic information may be smaller than the threshold value, and all of the diagnostic information may be outside the reference range. In such a case, by configuring the system so that abnormality processing is not performed, it is possible to effectively prevent abnormality processing from occurring frequently even when no abnormality is occurring, and thereby prevent a decrease in the reliability of the laser radar device.

[0132] Feature 12: The laser radar device according to any one of Features 2 to 11, wherein the set position of the section is shifted in the rotation direction of the rotating body or in the direction opposite to the rotation direction as the rotation of the rotating body progresses.

[0133] The pulse variations shown in Feature 2 can occur in any part of the encoder signal for one revolution (one cycle). Therefore, as shown in this feature, if the setting position of the section is configured to shift in the direction of rotation of the rotor or in the direction opposite to the direction of rotation as the revolution of the rotor progresses, the chances of an abnormality being overlooked can be reduced.

[0134] Furthermore, if the entire encoder signal is diagnosed in one revolution, the control load related to the diagnosis increases locally. In this regard, by configuring the diagnosis to be performed separately over multiple revolutions, it is possible to effectively suppress the increase in the local control load related to the diagnosis. This is preferable in terms of achieving coexistence with the output control of the laser light and the rotation control of the irradiation unit.

[0135] In particular, in combination with Feature 5 etc. (mutual comparison related), it is preferable to configure the setting positions of the different sections to be shifted in the rotation direction of the rotating body or in the direction opposite to the rotation direction according to the rotation of the rotating body. In this case, it is preferable to configure the positional relationship of the sections to be maintained during the shift.

[0136] Feature 13. The laser radar device according to Feature 12, wherein the intervals are defined so as not to overlap before and after the shift.

[0137] If the above-mentioned sections before and after the shift are configured not to overlap, the variation in pulses can be efficiently ascertained.

[0138] Feature 14. The diagnosis unit is configured to repeat the diagnosis for a plurality of revolutions under a condition in which the rotation speed of the rotating body is the target rotation speed, A laser radar device according to any one of features 1 to 13, wherein the sampling period of the diagnostic information is specified so that an integer multiple thereof does not match the rotation period of the rotating body rotating at a target rotation speed.

[0139] According to this characteristic configuration, it is possible to easily realize a configuration in which the sampling section gradually shifts with each revolution.

[0140] Feature 15. A laser radar device (laser radar device 10) including an irradiation unit (laser diode 21 and change unit 40) that irradiates a monitoring area (monitoring area DE) with laser light, and a light receiving unit (photodiode 31) that receives reflected light, which is the laser light reflected by an object (object OB), and that determines whether the object that reflected the laser light is located in the monitoring area based on the light receiving state (received light amount, etc.) of the reflected light by the light receiving unit, the irradiation unit includes a change unit (rotation block 41) that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder (rotary encoder 60) that includes a photointerrupter (photointerrupter 71), and an encoder disk (encoder disk 61) that is rotatable in the predetermined scanning direction together with the change unit, and that has light passing sections (slits 63) through which light from the photointerrupter can pass and non-passing sections (solid sections 64) that are alternately formed in the predetermined scanning direction, and that outputs an encoder signal having a continuous pulse-like waveform as the light passing sections and the non-passing sections pass in order through an optical path (detection position DP) of the photointerrupter as the encoder disk rotates; the light passing portions are formed at predetermined angular intervals in the predetermined scanning direction, and are configured to sequentially irradiate the laser light in accordance with a pulse period of the encoder signal by performing output control (e.g., ON / OFF control) of the laser light based on the encoder signal input from the rotary encoder; A laser radar device comprising a diagnostic unit (diagnostic unit 85 in control unit 12) that grasps the pulse period of the encoder signal under conditions in which the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signal is being output normally based on the grasped pulse period.

[0141] For example, if the center of the encoder disk and the center of rotation of the change unit are misaligned due to variations in the work involved in installing the rotary encoder, the pulse output pattern of part of the pulse train that makes up the encoder signal for one revolution may change from the basic pattern. Specifically, the pulse period may change, which could result in an abnormal signal. This type of phenomenon can also occur when the rotation axis of the change unit becomes loose due to wear or when the encoder disk is distorted or deformed.

[0142] If a laser beam is output based on an encoder signal that is not output normally as described above, the laser beam that should be emitted at a predetermined angle may be emitted at shorter or longer intervals than expected. In particular, if the laser beam is emitted at longer intervals than expected, there is a concern that object detection may be delayed compared to when such a change does not occur. This is undesirable because it reduces the detection accuracy of the encoder device. In particular, this hinders the accurate detection of distant objects or small objects.

[0143] In this regard, with the configuration shown in this feature, by focusing on the occurrence of changes in the pulses, the pulse period of the encoder signal is grasped, and based on that pulse period, a diagnosis is made as to whether the encoder signal is in a state where it can be output normally, thereby making it possible to quickly discover a situation where laser light cannot be emitted properly. This makes it possible to take measures such as encouraging the user to inspect the laser radar device. For the above reasons, delays in object detection can be suppressed, contributing to improved object detection accuracy by the laser radar device. This is advantageous for accurately detecting distant objects or small objects.

[0144] It should be noted that the technical ideas shown in Features 3 to 15 can also be applied to Feature 1.

[0145] Feature 16. A rotary encoder (rotary encoder 60) that is disposed on an object (rotating block 41) that rotates in a predetermined direction, is capable of rotating integrally with the object, and includes a rotating body (encoder disk 61) formed with a plurality of detectable portions (slits 63) aligned in the predetermined direction, and a detecting portion (photointerrupter 71) that can detect the detectable portions located at predetermined detection positions (detection positions DP), and outputs an encoder signal consisting of a pulse train corresponding to each of the detectable portions as the detectable portions pass the predetermined detection positions in sequence as the rotating body rotates, A rotary encoder having a diagnostic unit that grasps diagnostic information, which is information indicating the length of a specific waveform output in a part of a specified section of the encoder signal output in a specified revolution under conditions where the rotational speed of the rotating body is a target rotational speed, and diagnoses whether the encoder signal is in a state where it can be output normally based on the grasped diagnostic information.

[0146] For example, if the center of a rotating body (e.g., an encoder disk or magnetic drum) is misaligned with the center of rotation of the object being mounted due to variations in the installation process of a rotary encoder, the pulse output pattern of part of the pulse train that constitutes one revolution of the encoder signal may change from the basic pattern. Specifically, the pulse width or pulse period may change, which could result in an abnormal signal. Such an event may also occur if the rotating shaft of the variable section becomes loose due to wear or if the rotating body is distorted or deformed. If an attempt is made to control equipment based on an encoder signal that is not output normally as described above, there is a high possibility that normal control results will not be obtained.

[0147] In this regard, with the configuration shown in this feature, by focusing on the occurrence of changes in the pulses, diagnostic information indicating the length of a specific waveform is obtained from the encoder signal output at a predetermined cycle. By diagnosing whether the encoder signal can be output normally based on this diagnostic information, it is possible to quickly discover a situation in which it is difficult to normally control a device using the encoder signal.

[0148] Feature 17. A diagnostic system for diagnosing whether the rotary encoder (rotary encoder 60) is in a state where it can normally output the encoder signal as the detected parts pass through the predetermined detection positions in sequence as the rotary encoder (rotary encoder 60) rotates. The diagnostic system includes: a rotor (encoder disk 61) that is disposed on an object that rotates in a predetermined direction and can rotate integrally with the object; the rotor (encoder disk 61) has a plurality of detectable parts (slits 63) arranged in the predetermined direction; and a detector (photointerrupter 71) that can detect the detectable parts located at predetermined detection positions (detection positions DP). The rotary encoder (rotary encoder 60) outputs an encoder signal consisting of a pulse train corresponding to each of the detectable parts as the detected parts pass through the predetermined detection positions in sequence as the rotor rotates. A diagnostic system that grasps diagnostic information, which is information indicating the length of a specific waveform output in a portion of a specified rotation of the encoder signal output in a specified rotation when the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signal is in a state where it can be output normally based on the grasped diagnostic information.

[0149] According to this characteristic configuration, diagnostic information indicating the length of a specific waveform is obtained from the encoder signal output at a predetermined cycle. By diagnosing whether the encoder signal can be output normally based on this diagnostic information, it is possible to quickly discover a situation in which it is difficult to normally control a device using the encoder signal. [Explanation of symbols]

[0150] 10...laser radar device, 11...optical mechanism, 12...control unit, 21...laser diode, 31...photodiode, 40...change unit, 41...rotating block, 51...motor, 60...rotary encoder, 61...encoder disk, 63...slit, 71...photointerrupter, 85...diagnostic unit, CL1, CL2...central axis, DE...monitoring area, DP...detection position, S1 to S3, Sa1 to Sa3, Sb1 to Sb3, Sc1 to Sc3, SA to SJ...target section or section, OB...object.

Claims

1. A laser radar device comprising an irradiation unit that irradiates a monitoring area with laser light and a light receiving unit that receives reflected light that is the laser light reflected by an object, and that determines whether an object that reflected the laser light is located in the monitoring area based on a reception state of the reflected light by the light receiving unit, the irradiation unit includes a change unit that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder that includes a rotating body that can rotate integrally with the changing unit in the predetermined scanning direction and that is formed so that a plurality of detectable parts are lined up in the predetermined scanning direction, and a detecting unit that can detect the detectable parts that are located at predetermined detection positions, and that outputs an encoder signal consisting of a pulse train corresponding to each of the detectable parts as the detectable parts pass the predetermined detection positions in order as the rotating body rotates, the detection portions are formed at predetermined angular intervals in the predetermined scanning direction, and the laser light is periodically irradiated by controlling the output of the laser light based on the encoder signal input from the rotary encoder; a diagnostic unit that obtains diagnostic information, which is information indicating the length of a specific waveform output in a partial section of a predetermined revolution among the encoder signals output in a predetermined revolution under a condition in which the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signals are in a state in which they can be output normally based on the obtained diagnostic information; The diagnosing unit grasps the diagnostic information for each of the different sections, compares the grasped diagnostic information with each other and with a predetermined reference range, and diagnoses that the encoder signal is in a state where it is being output normally if the difference between the grasped diagnostic information is smaller than a threshold value and the grasped diagnostic information is all within the reference range, and diagnoses that the encoder signal is not in a state where it is being output normally if the difference between the grasped diagnostic information is larger than the threshold value or if any of the grasped diagnostic information is outside the reference range. This laser radar device

2. an abnormality process is executed when the diagnosing unit diagnoses that the encoder signal is not in a normal output state, 2. The laser radar device according to claim 1, wherein the abnormality processing is not performed when the difference between the acquired diagnostic information is smaller than the threshold value and when all of the acquired diagnostic information is outside the reference range.

3. A laser radar device comprising an irradiation unit that irradiates a monitoring area with laser light and a light receiving unit that receives reflected light that is the laser light reflected by an object, and that determines whether an object that reflected the laser light is located in the monitoring area based on a reception state of the reflected light by the light receiving unit, the irradiation unit includes a change unit that can change the irradiation direction of the laser light by rotating in a predetermined scanning direction, a rotary encoder that includes a rotating body that can rotate integrally with the changing unit in the predetermined scanning direction and that is formed so that a plurality of detectable parts are lined up in the predetermined scanning direction, and a detecting unit that can detect the detectable parts that are located at predetermined detection positions, and that outputs an encoder signal consisting of a pulse train corresponding to each of the detectable parts as the detectable parts pass the predetermined detection positions in order as the rotating body rotates, the detection portions are formed at predetermined angular intervals in the predetermined scanning direction, and the laser light is periodically irradiated by controlling the output of the laser light based on the encoder signal input from the rotary encoder; a diagnostic unit that obtains diagnostic information, which is information indicating the length of a specific waveform output in a partial section of a predetermined revolution among the encoder signals output in a predetermined revolution under a condition in which the rotation speed of the rotating body is a target rotation speed, and diagnoses whether the encoder signals are in a state in which they can be output normally based on the obtained diagnostic information; A laser radar device that shifts the set position of the section in the rotation direction of the rotating body or in the direction opposite to the rotation direction as the rotating body rotates.

4. 4. The laser radar device according to claim 3, wherein the diagnostic unit grasps the diagnostic information for each of the different sections and diagnoses whether the encoder signal is being output normally based on a comparison result between the grasped diagnostic information.

5. 4. The laser radar device according to claim 3, wherein the diagnosing unit grasps the diagnostic information for each of the different sections, compares the grasped diagnostic information with each other and with a predetermined reference range, and diagnoses that the encoder signal is in a state where it can be output normally if the difference between the grasped diagnostic information is smaller than a threshold value and the grasped diagnostic information is all within the reference range, and diagnoses that the encoder signal is not in a state where it can be output normally if the difference between the grasped diagnostic information is larger than the threshold value or if any of the grasped diagnostic information is outside the reference range.

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