Vehicle speed calculation device, mobile body, vehicle speed calculation method and program

Abstract

The present invention provides a vehicle speed calculation device that can accurately calculate the speed at which a moving object is traveling. [Solution] The vehicle speed calculation device 1 is mounted on a mobile vehicle (electric bicycle 2) having a vehicle body 10, a front wheel 11 positioned on the front side of the vehicle body 10 in the direction of travel, and a rear wheel 12 positioned on the rear side of the vehicle body 10 in the direction of travel. The device includes a power transmission mechanism 20 including a motor 21 that applies power to either the front wheel 11 or the rear wheel 12, a current detection unit 22 that detects the current value of the motor 21, a rotation speed detection unit 23 that detects the rotation speed of the motor 21, and a speed calculation unit 24 that calculates the first speed of the mobile vehicle (electric bicycle 2) based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23. The speed calculation unit 24 calculates the first speed of the mobile vehicle (electric bicycle 2) from the average rotation speed of the motor 21 over a predetermined period calculated based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23 when the current value is above a threshold.

Description

Technical Field

[0001] The present disclosure relates to a vehicle speed calculation device, a moving body, a vehicle speed calculation method, and a program.

Background Art

[0002] In recent years, it has become possible to detect the speed at which an electric bicycle travels by using a sensor mounted on the electric bicycle. For example, Patent Document 1 discloses an electric bicycle capable of calculating the speed at which an electric bicycle travels from information indicating the number of rotations per unit time of an electric motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a method of calculating the speed at which an electric bicycle travels from information indicating the number of rotations per unit time of an electric motor, since the number of rotations of the rotating shaft in the electric motor repeats acceleration and deceleration, there is a problem that it becomes difficult to calculate the traveling speed of the electric bicycle.

[0005] Therefore, an object of the present disclosure is to provide a vehicle speed calculation device or the like that can accurately calculate the speed at which a moving body travels.

Means for Solving the Problems

[0006] To achieve the above objective, a vehicle speed calculation device according to one aspect of the present disclosure is a vehicle speed calculation device mounted on a moving body having a vehicle body, front wheels positioned on the front side in the direction of travel of the vehicle body, and rear wheels positioned on the rear side in the direction of travel of the vehicle body, and comprises a power transmission mechanism including a motor that applies power to either the front wheels or the rear wheels, a current detection unit that detects the current value of the motor, a rotation speed detection unit that detects the rotation speed of the motor, and a speed calculation unit that calculates a first speed of the moving body based on the rotation speed of the motor detected by the rotation speed detection unit, wherein when the current value is equal to or greater than a threshold, the speed calculation unit calculates the first speed of the moving body from the average rotation speed of the motor over a predetermined period calculated based on the rotation speed of the motor detected by the rotation speed detection unit.

[0007] Furthermore, in order to achieve the above objective, the mobile body according to one aspect of this disclosure is equipped with a vehicle speed calculation device.

[0008] Furthermore, in order to achieve the above objective, a vehicle speed calculation method according to one aspect of the present disclosure is a vehicle speed calculation method mounted on a moving body having a vehicle body, front wheels positioned on the front side in the direction of travel of the vehicle body, and rear wheels positioned on the rear side in the direction of travel of the vehicle body, and includes a power transmission mechanism including a motor that applies power to either the front wheels or the rear wheels, a current detection unit detecting the current value of the motor, a rotation speed detection unit detecting the rotation speed of the motor, a speed calculation unit calculating a first speed of the moving body based on the rotation speed of the motor detected by the rotation speed detection unit, and, when the current value is equal to or greater than a threshold, the speed calculation unit calculating the speed of the moving body from the average rotation speed of the motor over a predetermined period calculated based on the rotation speed of the motor detected by the rotation speed detection unit.

[0009] Furthermore, a program relating to one aspect of this disclosure is a program for a computer to execute a vehicle speed calculation method. [Effects of the Invention]

[0010] According to the vehicle speed calculation device etc. described herein, the speed at which a moving object is traveling can be calculated with high accuracy. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram showing an electric bicycle according to an embodiment. [Figure 2] Figure 2 is a block diagram showing an electric bicycle according to an embodiment. [Figure 3] Figure 3 shows the speed of an electric bicycle calculated based on the motor's rotational speed. [Figure 4] Figure 4 is a flowchart showing an example of the operation of the vehicle speed calculation device according to the embodiment. [Modes for carrying out the invention]

[0012] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. Therefore, the numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit this disclosure. Accordingly, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0013] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. Therefore, for example, the scale and other aspects may not necessarily match in each figure. Also, in each figure, substantially identical components are given the same reference numerals, and redundant explanations are omitted or simplified.

[0014] The following describes the vehicle speed calculation device, mobile body, vehicle speed calculation method, and program according to this embodiment.

[0015] (Embodiment) <Configuration and Function> First, the configuration and functions of the vehicle speed calculation device 1 and the electric bicycle 2 will be explained with reference to Figures 1 to 3.

[0016] Figure 1 is a schematic diagram showing an electric bicycle 2 according to an embodiment. Figure 2 is a block diagram showing an electric bicycle 2 according to an embodiment. Figure 3 is a diagram showing the speed of the electric bicycle 2 calculated based on the rotational speed of the motor 21. For example, Figure 3 shows the case where the vertical axis is speed and the horizontal axis is time. In Figure 3, the speed of the electric bicycle 2 calculated based on the rotational speed of the motor 21 is shown by a solid line, the average speed of the electric bicycle 2 calculated based on the rotational speed of the motor 21 is shown by a dashed line, the actual speed of the electric bicycle 2 is shown by a dashed line, the speed detected by the rotation sensor is shown by a dashed line, and the region (period) where the speed based on the rotational speed of the motor 21 is at its peak is shown by a dashed circle.

[0017] As shown in Figure 1, the electric bicycle 2 is an example of a mobile device that can travel on a surface using electric power. The mobile device is not limited to the electric bicycle 2. The mobile device includes vehicles that have a body 10 capable of traveling on a surface by the rotation of wheels, such as electric kick scooters and other small motorized bicycles. The small motorized bicycle may be a bicycle type vehicle or motorized bicycle that has a self-propelled function capable of independent movement using the power of a motor 21. In this embodiment, the electric bicycle 2 will be used as an example of a mobile device for explanation.

[0018] The electric bicycle 2 of this embodiment is an electric assist bicycle that assists the user's pedaling force on the pedals 16 with the auxiliary driving force (an example of power) of the motor 21. The electric bicycle 2 may have independent human-powered driving force that powers the wheels through pedaling force and auxiliary driving force that powers the wheels by the motor 21, or it may be a bicycle that can run (be self-propelled) using only the power of the motor 21.

[0019] Such an electric bicycle 2 may have an assist mode, a walking-pushing mode, and a self-running mode. The assist mode is a mode that assists the forward movement of the electric bicycle 2 based on the user's pedaling force on the pedal 16. The walking-pushing mode is a mode that assists the forward movement of the electric bicycle 2 based on the force applied by the user to push the vehicle body 10 forward when the user pushes and walks the electric bicycle 2. The self-running mode is a mode that assists the forward movement of the electric bicycle 2 when the user walks while supporting the electric bicycle 2.

[0020] Specifically, the electric bicycle 2 has a vehicle body 10, a front wheel 11, a rear wheel 12, a vehicle speed calculation device 1, a control device 40, an operation unit 31, and a battery 32.

[0021] The vehicle body 10 has a frame 13, a saddle 14, a handle 15, and a pedal 16.

[0022] The frame 13 is the framework of the electric bicycle 2. The frame 13 is made of a metal such as, for example, an aluminum alloy, iron, chrome molybdenum steel, steel, titanium, etc. Note that the frame 13 may be made of carbon, synthetic resin, or the like.

[0023] The front wheel 11 is rotatably attached to the front frame of the frame 13. The handle 15 is attached to the head tube of the frame 13. The battery 32, the motor 21, and the control device 40 are attached to the down tube of the frame 13. The saddle 14 is attached to the seat tube of the frame 13. The rear wheel 12 is attached to the rear fork of the frame 13. A rear sprocket 12b that interlocks with the axle of the rear wheel 12 is attached to the rear frame of the frame 13. A chain 19 is bridged between the rear sprocket 12b and the front sprocket 12c. Thereby, the rotational force of the front sprocket 12c rotated by stepping on the pedal 16 is transmitted to the rear wheel 12 via the chain 19 and the rear sprocket 12b.

[0024] Saddle 14 is the part where the user sits. Saddle 14 is mounted to the seat tube in an adjustable position.

[0025] The handlebars 15 allow the user to change the steering angle of the electric bicycle 2, for example, when operating the electric bicycle 2. A pair of grips and a pair of brake levers are provided at both ends of the handlebars 15.

[0026] The pedal 16 receives the user's pedaling force, for example, when the user is riding the electric bicycle 2. The pedal 16 is rotatably mounted to the crank 17.

[0027] The front wheel 11 of the electric bicycle 2 is a wheel having a tire 11a for the vehicle body 10 to travel on. The front wheel 11 is supported by the front fork so that it can rotate around an axis along the left-right direction. The front wheel 11 may also receive power from a motor 21, for example, a motor 21 may be provided that provides a driving force to rotate the front wheel 11.

[0028] The rear wheel 12 is a wheel having a tire 12a for the vehicle body 10 to travel on. The rear wheel 12 is supported by a rear fork so that it can rotate around an axis along the left-right direction. The rear wheel 12 may also receive power from a motor 21, for example, a motor 21 may be provided that provides a driving force to rotate the rear wheel 12. The power output from the motor 21 may be transmitted to the rear wheel 12, for example, a motor 21 may be provided that provides a driving force to rotate the rear wheel 12.

[0029] The vehicle speed calculation device 1 can calculate the speed of an electric bicycle 2, which comprises a vehicle body 10, a front wheel 11 positioned on the front side of the vehicle body 10 in the direction of travel, and a rear wheel 12 positioned on the rear side of the vehicle body 10 in the direction of travel. In this embodiment, the first speed and second speed, which will be described later, are sometimes collectively referred to simply as the speed of the electric bicycle 2.

[0030] Specifically, the vehicle speed calculation device 1 comprises a power transmission mechanism 20, a current detection unit 22, a rotation speed detection unit 23, and a speed calculation unit 24.

[0031] The power transmission mechanism 20 includes a chain 19, a rear sprocket 12b, and a crank 17.

[0032] The chain 19 transmits the rotational force of the front sprocket 12c, which is rotated when the pedal 16 is pressed down, and the auxiliary driving force added from the motor 21, to the rear sprocket 12b. The chain 19 is a power transmission body such as a belt, shaft, wire, or gear.

[0033] The rear sprocket 12b is attached to the rear wheel 12 and can rotate the rear wheel 12 by power transmitted to the chain 19.

[0034] The crank 17 has a front sprocket 12c and is rotatably mounted on the frame 13 relative to the crank shaft 17b. A pedal 16 is attached to the crank 17. When pedaling force is applied to the pedal 16, the crank 17 rotates around the crank shaft 17b, and the human-powered driving force from this rotation is transmitted to the rear sprocket 12b via the front sprocket 12c and chain 19, and then from the rear sprocket 12b to the rear wheel 12. In other words, when the pedal 16 is pressed down by the user, the front sprocket 12c rotates via the crank arm and crank shaft 17b. Then, the rotation of the front sprocket 12c causes the rear sprocket 12b to rotate via the chain 19, and the rear wheel 12 rotates as well.

[0035] The power transmission mechanism 20 further includes a motor 21.

[0036] The motor 21 can apply power to either the front wheel 11 or the rear wheel 12. For example, the motor 21 outputs an auxiliary driving force, adding an auxiliary drive to the pedaling force, which is the human driving force, and transmits it to the rear wheel 12 via the chain 19.

[0037] The motor 21 is housed in a resin or metal casing and integrated into a unit. Sensors and other components are installed inside the casing. The motor 21 is mounted on the frame 13.

[0038] The motor 21 can provide auxiliary driving force to assist in the movement of the electric bicycle 2. The motor 21 is powered by electricity from the battery 32, based on control by the control device 40. The motor 21 can rotate the front wheel 11 by transmitting rotational torque as auxiliary driving force to the front sprocket 12c via the chain 19, or rotate the rear wheel 12 by transmitting it to the rear sprocket 12b via the chain 19. The rotational torque includes auxiliary driving force from the motor 21 to be added to the human driving force, and auxiliary driving force applied to the force used to push or support the electric bicycle 2 while walking.

[0039] The motor 21 can add auxiliary driving force to the human-powered driving force based on the force applied to the pedals 16 while the assist mode is running. The motor 21 can also add auxiliary driving force to the force applied to the electric bicycle 2 while the push-walk mode is running, or add auxiliary driving force to allow the electric bicycle 2 to move on its own while being supported by the user while the self-propelled mode is running.

[0040] The current detection unit 22 can detect the current value of the motor 21. The current detection unit 22 can, for example, detect the current value flowing through the inverter circuit provided in the motor 21. The current detection unit 22 can detect the current value flowing through the inverter circuit of the motor 21 and output the detected current value to the speed calculation unit 24.

[0041] The rotation speed detection unit 23 can detect the rotation speed of the motor 21. For example, when pedaling force is applied to the pedal 16 of the electric bicycle 2, the motor 21 is configured to rotate its rotating shaft in order to provide auxiliary driving force to the chain 19. Therefore, the rotation speed detection unit 23 can detect the rotation speed of the rotating shaft of the motor 21 (hereinafter sometimes referred to as the rotation speed of the motor 21). The rotation speed detection unit 23 can output the detected rotation speed to the speed calculation unit 24.

[0042] The speed calculation unit 24 can acquire the rotational speed of the motor 21 detected by the rotational speed detection unit 23. Based on the rotational speed of the motor 21 detected by the rotational speed detection unit 23, the speed calculation unit 24 can calculate the first speed of the electric bicycle 2.

[0043] Specifically, the speed calculation unit 24 can also acquire the current value flowing through the inverter circuit of the motor 21, as detected by the current detection unit 22, either continuously or at regular intervals. At this time, the speed calculation unit 24 can determine whether the current value acquired from the speed calculation unit 24 is above a threshold. If the current value acquired from the speed calculation unit 24 is above a threshold, the speed calculation unit 24 can calculate the average rotational speed of the motor 21 over a predetermined period, calculated based on the rotational speed of the motor 21 detected by the rotational speed detection unit 23, and calculate the first speed of the electric bicycle 2 from the calculated average rotational speed.

[0044] More specifically, the speed calculation unit 24 extracts a period in which the speed of the electric bicycle 2 detected by a rotation sensor located on the front or rear wheel (shown by the dashed line in Figure 3) matches or substantially matches the speed of the electric bicycle 2 calculated based on the rotation speed of the motor 21 (shown by the solid line in Figure 3). The extracted period is the peak period shown by the solid line in Figure 3, indicated by the dashed circle, where the current value is above a threshold. The speed calculation unit 24 can calculate the first speed of the electric bicycle 2 by calculating the average rotation speed of the motor 21 during the extracted period. The first speed of the electric bicycle 2 calculated in this way is equivalent to the speed of the electric bicycle 2 shown by the single dashed line in Figure 3 or the double dashed line in Figure 3. The region shown by the dashed circle in Figure 3 is the region where the rotation speed of the motor 21 is above a value indicating the rotation speed of the motor 21 converted from the threshold value of the current value.

[0045] For example, the speed calculation unit 24 may have a motor rotation sensor that detects the number of rotations per unit time of the motor 21. Also, if the acquired current value is less than a threshold, the speed calculation unit 24 does not need to calculate the average rotation speed of the motor 21, and does not need to calculate the first speed of the electric bicycle 2. The predetermined period is, for example, a few seconds.

[0046] Furthermore, if the current value is above a threshold, it is considered that the motor 21 is applying auxiliary driving force to either the front wheel 11 or the rear wheel 12, and a predetermined tension is applied to the chain 19, resulting in a taut chain. It can also be considered that if pedaling force is applied to the pedal 16, a predetermined tension is applied to the chain 19, resulting in a taut chain. Therefore, in either case, the speed calculation unit 24 can determine that a predetermined tension is applied to the chain 19, resulting in a taut chain.

[0047] Furthermore, if the current value is above a threshold and the fluctuation value of the motor 21's rotational speed is within a predetermined range during the predetermined period, the speed calculation unit 24 may calculate the first speed of the electric bicycle 2 from the average rotational speed of the motor 21 during the predetermined period. In other words, if the current value is below a threshold or the fluctuation value of the motor 21's rotational speed is outside the predetermined range, the speed calculation unit 24 may exclude the first speed of the electric bicycle 2 calculated from the average rotational speed of the motor 21 during the predetermined period. Note that if the current value is below a threshold or the fluctuation value of the motor 21's rotational speed is outside the predetermined range, the speed calculation unit 24 does not need to calculate the average rotational speed of the motor 21 and does not need to calculate the first speed of the electric bicycle 2. That is, if the current value is above a threshold and the auxiliary driving force of the motor 21 is stably applied to the chain 19 during the predetermined period, the speed calculation unit 24 may calculate the first speed of the electric bicycle 2.

[0048] This is because, when the motor's rotational speed fluctuates significantly, the motor's rotational speed repeatedly accelerates and decelerates, resulting in a phenomenon where the motor's rotational speed catches up to and then falls behind the electric bicycle's speed. In this case, conventional techniques would not be able to accurately calculate the electric bicycle's speed even if the speed is calculated from the motor's average rotational speed over a predetermined period. Therefore, this embodiment allows for the calculation of the first speed of the electric bicycle 2 in a way that solves the problems of the conventional technique described above.

[0049] The vehicle speed calculation device 1 may further include an air pressure estimation unit 25.

[0050] In this case, the air pressure estimation unit 25 can estimate the air pressure of either the tire 11a of the front wheel 11 or the tire 12a of the rear wheel 12 of the electric bicycle 2, based on at least the first speed calculated by the speed calculation unit 24.

[0051] Furthermore, the air pressure estimation unit 25 can acquire the rotational speed of the front wheel 11 or rear wheel 12 to which the auxiliary driving force of the motor 21 is not applied. For example, the air pressure estimation unit 25 has a rotation sensor that acquires the rotational speed of the front wheel 11 or rear wheel 12 to which the auxiliary driving force of the motor 21 is not applied.

[0052] The air pressure estimation unit 25 can estimate the air pressure of the front wheel 11 and rear wheel 12 of the electric bicycle 2 based on the second speed of the electric bicycle 2 calculated from the rotational speed of the front wheel 11 or the rotational speed of the rear wheel 12 without the acquired auxiliary driving force of the motor 21, and the first speed described above. For example, the air pressure estimation unit 25 calculates the second speed of the electric bicycle 2 from the rotational speed of the front wheel 11 or the rear wheel 12 detected by the rotation sensor. The air pressure estimation unit 25 compares the first speed and the second speed. For example, using the second speed of the front wheel 11 as a reference, the air pressure estimation unit 25 can estimate that the air pressure of the rear wheel 12 is lower than the reference pressure if the ratio of the first speed of the rear wheel 12 to the second speed of the front wheel 11 (first speed of the rear wheel 12 / second speed of the front wheel 11) is greater than or equal to a predetermined ratio, and can estimate that the air pressure of the front wheel 11 is lower than the reference pressure if the ratio of the first speed of the rear wheel 12 to the second speed of the front wheel 11 is less than the predetermined ratio. Note that the air pressure estimation unit 25 is not an essential component of the vehicle speed calculation device 1.

[0053] The control device 40 of the electric bicycle 2 can drive the motor 21 according to the operating mode of the electric bicycle 2. Specifically, the control device 40 switches between assist mode and push-walk mode or self-propelled mode to execute each mode. Assist mode is executed when the user is riding the electric bicycle 2 after the power is turned on by operating the control unit 31. When executing assist mode, the control device 40 can determine the magnitude of the auxiliary driving force generated by the motor 21 based on the pedaling force applied to the pedal 16 and the speed of the electric bicycle 2. Push-walk mode is executed when the user is not riding the electric bicycle 2, the power is turned on by operating the control unit 31, and the user is pushing the frame 10 of the electric bicycle 2. When executing push-walk mode, the control device 40 can determine the magnitude of the auxiliary driving force generated by the electric motor 43 based on the pushing force applied to the electric bicycle 2 and the speed of the electric bicycle 2. Self-propelled mode is executed similarly to push-walk mode when the user is not riding the electric bicycle 2 and is walking while supporting the frame 10 of the electric bicycle 2. In self-propelled mode, the user does not apply any force to push the vehicle body 10 forward. When self-propelled mode is being performed, the control device 40 can determine the magnitude of a predetermined auxiliary driving force generated by the electric motor 43.

[0054] The control unit 31 can receive push-walking operations or self-propelling operations to execute push-walking mode or self-propelling mode. While the control unit 31 is being operated by the user, the control unit 31 continuously outputs a mode-on signal to the control device 40 to execute push-walking mode or self-propelling mode. On the other hand, while the control unit 31 is not being operated, the control unit 31 does not output a mode-on signal to the control device 40.

[0055] The control unit 31 is a terminal device such as a cycle computer equipped with a light switch for turning on the headlights, etc. The control unit 31 has buttons, etc., to accept operations from the user.

[0056] The control unit 31 has a notification unit that can output the calculated speed of the electric bicycle 2. For example, the notification unit is a display unit that can display the speed of the electric bicycle 2. The display unit is, for example, a liquid crystal display, an organic EL display, etc. The notification unit may also be an acoustic unit that notifies the area around the vehicle body 10 of the speed of the electric bicycle 2 by sound. The notification unit may also be a light source unit that notifies the user of the speed of the electric bicycle 2 by light. The light source unit may be an LED module that emits single-color or multi-color light, etc.

[0057] Battery 32 is a rechargeable battery that stores power for driving the motor 21. Battery 32 is, for example, a secondary battery, but it may also be a capacitor or the like. Battery 32 is electrically connected to the motor 21. Specifically, battery 32 supplies power to the motor 21.

[0058] <Operation> This section describes the vehicle speed calculation device 1, the electric bicycle 2, the vehicle speed calculation method, and the control processing of the program.

[0059] Figure 4 is a flowchart showing an example of the operation of the vehicle speed calculation device 1 according to the embodiment.

[0060] First, the current detection unit 22 detects the current value of the motor 21 at regular intervals (S11). The current detection unit 22 can output the detected current value to the speed calculation unit 24 at regular intervals.

[0061] Next, the rotation speed detection unit 23 detects the rotation speed of the motor 21 at regular intervals (S12). The rotation speed detection unit 23 outputs the detected rotation speed to the speed calculation unit 24 at regular intervals.

[0062] Next, the speed calculation unit 24 acquires the current value flowing through the inverter circuit of the motor 21, which has been detected by the current detection unit 22, at regular intervals. The speed calculation unit 24 then determines whether the current value acquired from the speed calculation unit 24 is above a threshold (S13).

[0063] Next, if the current value obtained from the speed calculation unit 24 is greater than or equal to a threshold (YES in S13), the speed calculation unit 24 calculates the average rotational speed of the motor 21 over a predetermined period, which is calculated based on the rotational speed of the motor 21 detected by the rotational speed detection unit 23 (S14).

[0064] Next, the speed calculation unit 24 calculates the first speed of the electric bicycle 2 from the calculated average rotation speed (S15). Then, the vehicle speed calculation device 1 finishes processing and returns to step S11.

[0065] On the other hand, if the acquired current value is less than a threshold (NO in S13), the speed calculation unit 24 may exclude the first calculated speed of the electric bicycle 2 (S16). Then, the vehicle speed calculation device 1 finishes processing and returns to step S11.

[0066] <Effects and Effects> Next, the effects of the vehicle speed calculation device 1, electric bicycle 2, vehicle speed calculation method, and program in this embodiment will be described.

[0067] As described above, the vehicle speed calculation device 1 of Technology 1 according to this embodiment is a vehicle speed calculation device 1 mounted on a mobile vehicle (electric bicycle 2) having a vehicle body 10, a front wheel 11 positioned on the front side of the vehicle body 10 in the direction of travel, and a rear wheel 12 positioned on the rear side of the vehicle body 10 in the direction of travel, and comprises a power transmission mechanism 20 including a motor 21 that applies power to either the front wheel 11 or the rear wheel 12, a current detection unit 22 that detects the current value of the motor 21, a rotation speed detection unit 23 that detects the rotation speed of the motor 21, and a speed calculation unit 24 that calculates the first speed of the mobile vehicle (electric bicycle 2) based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23, and the speed calculation unit 24 calculates the first speed of the mobile vehicle (electric bicycle 2) from the average rotation speed of the motor 21 over a predetermined period calculated based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23 when the current value is above a threshold.

[0068] For example, the speed of a moving object calculated based on the rotation speed of the front wheel and the speed of a moving object calculated based on the rotation speed of the rear wheel, which is rotated with the auxiliary driving force of the motor, should be considered to be equivalent. However, with conventional technology, they may differ. In principle, (rear wheel rotation speed) / (front wheel rotation speed) should be "1," but it is known that as the gear ratio of the rear wheel rotation speed decreases, it tends to approach "0" from "1." This is because, as shown by the solid line in Figure 3, the motor repeatedly accelerates and decelerates, so even if you simply calculate the average speed of the electric bicycle based on the motor rotation speed shown by the dashed line in Figure 3, it will be calculated to be slower than the actual speed of the electric bicycle shown by the dashed line in Figure 3, and as a result it approaches "0" from "1."

[0069] Therefore, by setting a constant parameter called a threshold for the rear wheel rotation speed, it is expected that (rear wheel rotation speed) / (front wheel rotation speed) can be brought closer to "1". However, the configuration (vehicle type) of the moving object varies, and since each vehicle type is different, the state of the solid line in Figure 3 differs, and as a result, each parameter will also differ. In order to accurately detect the speed of the moving object, it is necessary to set each parameter according to the vehicle type, and each parameter will need to be managed according to the vehicle type. In addition, experimental data will need to be obtained for moving objects of various vehicle types in order to set the parameters. Furthermore, even if each parameter is set according to the vehicle type, there is a risk that the production efficiency of the moving object will decrease.

[0070] For these reasons, the above-mentioned methods are not practical.

[0071] Therefore, in this embodiment, the speed calculation unit 24 can calculate the first speed of the electric bicycle 2 when the current value is above a threshold. Specifically, the speed calculation unit 24 extracts the period (the peak period of the solid line in Figure 3, indicated by the dashed circle in Figure 3) during which the speed of the electric bicycle 2 detected by the rotation sensor shown by the dashed line in Figure 3 and the speed of the electric bicycle 2 calculated based on the rotation speed of the motor 21 shown by the solid line in Figure 3 coincide or substantially coincide. The speed calculation unit 24 can calculate the first speed of the electric bicycle 2 by calculating the average rotation speed of the motor 21 during the extracted period. The calculated first speed of the electric bicycle 2 is equivalent to the speed of the electric bicycle 2 shown by the dashed line in Figure 3 or the speed of the electric bicycle 2 shown by the dashed line in Figure 3. For this reason, the first speed of the electric bicycle 2 can be calculated with high accuracy.

[0072] Therefore, the vehicle speed calculation device 1 can accurately calculate the speed at which the electric bicycle 2 is traveling.

[0073] In particular, since the first speed can be calculated as described above, it becomes unnecessary to set parameters according to the type of electric bicycle 2, and the speed at which the electric bicycle 2 travels can be calculated accurately regardless of the type of electric bicycle 2, while also suppressing a decrease in the production efficiency of the vehicle speed calculation device 1.

[0074] Furthermore, in this case, it becomes possible to obtain the speed of the moving object with high accuracy without having to mount a speed sensor on the object itself.

[0075] Furthermore, the vehicle speed calculation device 1 of Technology 2 according to this embodiment is the vehicle speed calculation device 1 described in Technology 1. In this case, the power transmission mechanism 20 further has a chain 19 to which the power of the motor 21 is added, and the speed calculation unit 24 further determines that a predetermined tension is applied to the chain 19 when the current value is above a threshold value.

[0076] According to this, when the speed of the electric bicycle 2 detected by the rotation sensor shown by the dashed line in Figure 3 matches or substantially matches the speed of the electric bicycle 2 calculated based on the rotation speed of the motor 21 shown by the solid line in Figure 3, a predetermined tension is applied to the chain 19. Therefore, if it can be determined that a predetermined tension is applied to the chain 19, it means that current is flowing to the motor 21 and the motor 21 is rotating and driving, so the first speed of the electric bicycle 2 can be calculated accurately from the rotation speed of the motor 21.

[0077] For example, when traveling downhill, the rotational speed of motor 21 becomes 0, which can prevent the initial speed of the electric bicycle 2 from being calculated as 0.

[0078] Furthermore, the vehicle speed calculation device 1 of Technology 3 according to this embodiment further comprises a pedal 16 to which the user's pedaling force is applied, the power transmission mechanism 20 further comprises a chain 19 to which the power of the motor 21 is applied, and the speed calculation unit 24 further determines that a predetermined tension is applied to the chain 19 when pedaling force is applied to the pedal 16, as described in Technology 1.

[0079] According to this, when the speed of the electric bicycle 2 detected by the rotation sensor shown by the dashed line in Figure 3 matches or substantially matches the speed of the electric bicycle 2 calculated based on the rotation speed of the motor 21 shown by the solid line in Figure 3, a predetermined tension is applied to the chain 19. Therefore, if it can be determined that a predetermined tension is applied to the chain 19, it means that current is flowing to the motor 21, causing it to rotate and drive, in the case where the motor 21 is adding auxiliary driving force to the human power driving force based on the force applied to the pedal 16. Thus, the first speed of the electric bicycle 2 can be calculated accurately from the rotation speed of the motor 21.

[0080] Furthermore, the vehicle speed calculation device 1 of Technology 4 according to this embodiment is the vehicle speed calculation device 1 described in any one of Technologies 1 to 3. In this case, the speed calculation unit 24 calculates the first speed of the mobile vehicle (electric bicycle 2) from the average rotational speed of the motor 21 during a predetermined period if the current value is above a threshold and the fluctuation value of the rotational speed of the motor 21 is within a predetermined range during a predetermined period.

[0081] According to this, during the period indicated by the dashed circle in Figure 3, which includes the peak of the solid line in Figure 3 where the current value exceeds the threshold, the rotational speed of the motor 21 is stable for a certain period. Therefore, by calculating the first speed of the electric bicycle 2 in this case, the speed of the electric bicycle 2 can be calculated with high accuracy.

[0082] Furthermore, the vehicle speed calculation device 1 of Technology 5 according to this embodiment is a vehicle speed calculation device 1 according to any one of Technologies 1 to 4, further comprising an air pressure estimation unit 25 that estimates the air pressure of either the front wheel 11 or the rear wheel 12 of the mobile body (electric bicycle 2) based on at least the first speed calculated by the speed calculation unit 24.

[0083] According to this, the air pressure of the front wheel 11 or rear wheel 12 to which the motor 21's power is applied can be estimated, eliminating the need for a separate air pressure sensor to detect the air pressure. This helps to suppress the soaring manufacturing costs of the electric bicycle 2.

[0084] Furthermore, the vehicle speed calculation device 1 of Technology 6 according to this embodiment is the vehicle speed calculation device 1 described in Technology 5. In this case, the air pressure estimation unit 25 estimates the air pressure of the front wheel 11 and rear wheel 12 of the mobile body (electric bicycle 2) based on the second speed and first speed of the mobile body (electric bicycle 2) calculated from the rotational speed of the front wheel 11 or rear wheel 12 to which the motor 21's power is not applied.

[0085] According to this method, the air pressure of the front wheel 11 and the rear wheel 12 can be estimated, eliminating the need for a separate air pressure sensor to detect the air pressure. This helps to suppress the increase in manufacturing costs of the electric bicycle 2.

[0086] Furthermore, the vehicle speed calculation device 1 of Technology 7 according to this embodiment is the vehicle speed calculation device 1 described in any one of Technologies 1 to 6. In this case, the speed calculation unit 24 excludes the first speed of the moving body (electric bicycle 2) calculated from the average rotational speed of the motor 21 over a predetermined period when the current value is less than a threshold.

[0087] According to this, when the current value is below the threshold, for example, when the user is not applying any force to the pedal 16, it is possible to prevent the electric bicycle 2 from becoming 0 speed even when it is going downhill because the motor 21's rotation speed is 0. In this way, even though the electric bicycle 2 is moving, it is possible to prevent it from outputting a speed different from its actual speed.

[0088] Furthermore, the mobile body of Technology 8 according to this embodiment includes the vehicle speed calculation device 1 described in any one of Technology 1 to 7.

[0089] In this case as well, the same effects as described above will be produced.

[0090] Furthermore, the vehicle speed calculation method of Technology 9 according to this embodiment is a vehicle speed calculation method mounted on a mobile vehicle (electric bicycle 2) having a vehicle body 10, a front wheel 11 positioned on the front side of the vehicle body 10 in the direction of travel, and a rear wheel 12 positioned on the rear side of the vehicle body 10 in the direction of travel, and includes a power transmission mechanism 20 including a motor 21 that applies power to either the front wheel 11 or the rear wheel 12, a current detection unit 22 detecting the current value of the motor 21, a rotation speed detection unit 23 detecting the rotation speed of the motor 21, a speed calculation unit 24 calculating a first speed of the mobile vehicle (electric bicycle 2) based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23, and, when the current value is above a threshold, the speed calculation unit 24 calculating a first speed of the mobile vehicle (electric bicycle 2) from the average rotation speed of the motor 21 over a predetermined period calculated based on the rotation speed of the motor 21 detected by the rotation speed detection unit 23.

[0091] In this case as well, the same effects as described above will be produced.

[0092] Furthermore, the program of technology 10 according to this embodiment is a program for a computer to execute the vehicle speed calculation method of technology 9.

[0093] In this case as well, the same effects as described above will be produced.

[0094] (Other variations, etc.) Although the present disclosure has been described above based on embodiments, the present disclosure is not limited to these embodiments.

[0095] For example, in the vehicle speed calculation device according to the above embodiment, when the current value is less than a threshold, it can be inferred that no tension is applied to the chain, or that there is substantially no tension applied to it. For this reason, in a mobile vehicle, the control device may obtain the motor current value from the current detection unit, and when it determines that the current value is less than a threshold, it may notify the operator via the notification unit of the operation unit that it is time to change the gear of the transmission mounted on the mobile vehicle. This makes it possible to switch gears at an appropriate timing and suppress the physical load applied to the motor associated with the gear change. Here, the transmission is composed of a well-known gear change mechanism such as a planetary gear or multi-stage gear having multiple drive force transmission paths with different gear ratios.

[0096] Furthermore, the current detection unit, rotational speed detection unit, speed calculation unit, and air pressure estimation unit used in the vehicle speed calculation device, etc., according to the above embodiment are typically implemented as LSIs, which are integrated circuits. These may be individually integrated into a single chip, or some or all of them may be integrated into a single chip.

[0097] Furthermore, integrated circuit implementation is not limited to LSIs; it may also be achieved using dedicated circuits or general-purpose processors. Alternatively, an FPGA (Field Programmable Gate Array), which can be programmed after LSI manufacturing, or a reconfigurable processor capable of reconfiguring the connections and settings of circuit cells within the LSI, may be used.

[0098] In each of the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0099] Furthermore, all figures used above are illustrative to illustrate the present disclosure, and the embodiments of this disclosure are not limited to the figures exemplified.

[0100] Furthermore, the division of functional blocks in the block diagram is just one example; multiple functional blocks can be implemented as a single functional block, a single functional block can be divided into multiple parts, or some functions can be moved to other functional blocks. In addition, the functions of multiple functional blocks with similar functions can be processed in parallel or time-sharing by a single piece of hardware or software.

[0101] Furthermore, the order in which each step in the flowchart is performed is illustrative for the purpose of specifically illustrating this disclosure, and may be in a different order. Also, some of the above steps may be performed simultaneously (in parallel) with other steps.

[0102] Furthermore, this disclosure also includes forms obtained by applying various modifications to the embodiments that a person skilled in the art could conceive, and forms realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of this disclosure. [Explanation of Symbols]

[0103] 1 Vehicle speed calculation device 2. Electric bicycle (mobility device) 10 car bodies 11 Front Wheel 12 Rear wheels 19 chain 20 Power transmission mechanism 21 Motor 22 Current detection unit 23. Rotation speed detection unit 24 Speed ​​calculation section 25 Air pressure estimation unit

Claims

1. A vehicle speed calculation device mounted on a moving body having a vehicle body, front wheels positioned on the front side of the vehicle body in the direction of travel, and rear wheels positioned on the rear side of the vehicle body in the direction of travel, A power transmission mechanism including a motor that applies power to either the front wheel or the rear wheel, A current detection unit for detecting the current value of the motor, A rotation speed detection unit for detecting the rotation speed of the motor, The system includes a speed calculation unit that calculates a first speed of the moving body based on the rotation speed of the motor detected by the rotation speed detection unit, When the current value is equal to or greater than a threshold, the speed calculation unit calculates the first speed of the moving body from the average rotational speed of the motor over a predetermined period, which is calculated based on the rotational speed of the motor detected by the rotational speed detection unit. Vehicle speed calculation device.

2. The power transmission mechanism further includes a chain to which the power of the motor is added. The speed calculation unit further determines that a predetermined tension is being applied to the chain when the current value is equal to or greater than a threshold value. The vehicle speed calculation device according to claim 1.

3. Furthermore, it features a pedal that allows the user to apply additional force. The power transmission mechanism further includes a chain to which the power of the motor is added. The speed calculation unit further determines that a predetermined tension is applied to the chain when pedaling force is applied to the pedal. The vehicle speed calculation device according to claim 1.

4. The speed calculation unit calculates the first speed of the moving body from the average rotational speed of the motor during the predetermined period if the current value is equal to or greater than a threshold value and the fluctuation value of the motor's rotational speed during the predetermined period is within a predetermined range. A vehicle speed calculation device according to any one of claims 1 to 3.

5. Furthermore, the system includes an air pressure estimation unit that estimates the air pressure of either the front wheel or the rear wheel of the moving body based on at least the first speed calculated by the speed calculation unit. A vehicle speed calculation device according to any one of claims 1 to 3.

6. The air pressure estimation unit estimates the air pressure of the front and rear wheels of the moving body based on the second speed and the first speed of the moving body, which are calculated from the rotational speed of the front or rear wheel to which the motor power is not applied. The vehicle speed calculation device according to claim 5.

7. The speed calculation unit excludes the first speed of the moving body, which is calculated from the average rotational speed of the motor during the predetermined period, when the current value is less than a threshold. A vehicle speed calculation device according to any one of claims 1 to 3.

8. The vehicle speed calculation device is provided according to any one of claims 1 to 3. A mobile object.

9. A method for calculating vehicle speed mounted on a moving body having a vehicle body, front wheels positioned on the front side of the vehicle body in the direction of travel, and rear wheels positioned on the rear side of the vehicle body in the direction of travel, A power transmission mechanism including a motor that applies power to either the front wheel or the rear wheel, The current detection unit detects the current value of the motor, The rotation speed detection unit detects the rotation speed of the motor, Based on the rotational speed of the motor detected by the rotational speed detection unit, the speed calculation unit calculates the first speed of the moving body. When the current value is equal to or greater than a threshold, the speed calculation unit calculates the speed of the moving body from the average rotation speed of the motor over a predetermined period, which is calculated based on the rotation speed of the motor detected by the rotation speed detection unit. Vehicle speed calculation method.

10. A computer for executing the vehicle speed calculation method described in claim 9. program.

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