Control method and system of electric bicycle

Abstract

The present invention relates to a method and system for controlling an electric bicycle, the method for controlling an electric bicycle according to one embodiment of the present application comprising the steps of: detecting a pedal speed and a wheel speed; applying a wheel speed parameter to a difference between a wheel speed command generated by multiplying the pedal speed by a gear ratio and the wheel speed to generate a wheel torque command; applying a pedal speed parameter to a difference between the wheel speed command and the wheel speed to generate a pedal torque command; controlling an electric machine based on the wheel torque command; and controlling a generator based on the pedal torque command.

Description

Technical Field

[0001] The present application relates to a control method and system for an electric bicycle. More specifically, the present application relates to a control method and system for an electric bicycle, which improves pedal feel by controlling pedal speed based on a pedal speed parameter that is independent of a wheel speed parameter in a chainless electric bicycle driven by a motor. Background Art

[0002] Electric bicycles (including electric cargo bicycles (e-cargo)) use electricity to rotate the motor to assist or propel the bicycle. The Pedal Assistance System (PAS) system uses the motor's power to assist the pedaling force used to drive the wheels, while the throttle system uses the motor's power alone to drive the wheels by pulling the handlebars. There are also PAS / throttle electric bicycles that support both PAS and throttle modes.

[0003] Typically, chainless electric bicycles detect the speed at which the user rotates the pedals and control the motor speed proportionally to that speed. Because the chain is not connected to the pedals and therefore exerts no load, the alternator (alternator) connected to the pedals is controlled to produce the same pedal load as on bicycles with chains. By controlling the pedal load according to the speed of the electric bicycle, the user experiences a pedal feel similar to that of a bicycle with a chain.

[0004] In addition, when generating a pedal feel in the related art, a motor torque is generated by rotating a pedal, and the pedal feel is generated based on the motor torque.

[0005] According to this control, when the rotation speed of the pedal is greater than the speed of the wheel, the pedal feel becomes heavier, and when the rotation speed of the pedal is less than the speed of the wheel, the pedal feel becomes lighter.

[0006] However, when the pedal feel is formed based on the wheel speed, for example, when the pedal is pressed hard, a slip-through phenomenon may occur in which the pedal is pushed away due to a weak pedal reaction force, thereby causing inconvenience to the driver.

[0007] Therefore, a control method and system for an electric bicycle are needed, which can produce a riding feeling more similar to that of a bicycle with a chain in a chainless electric bicycle and prevent the pedal from being pushed off, thereby allowing the driver to feel a stable pedaling feeling. Summary of the Invention

[0008] Problems to be solved by the invention

[0009] The present application is proposed to solve the above-mentioned problems, and its purpose is to provide a control method and system for an electric bicycle, which includes a wheel speed controller that is independent of controlling the acceleration performance of the electric bicycle and is suitable for a pedal speed controller of the pedal system, thereby being able to perform control suitable for each system.

[0010] In addition, the present application aims to provide a control method and system for an electric bicycle, which can provide a stable pedal feel by controlling the pedal feel through a pedal speed parameter, regardless of the characteristics of the electric bicycle.

[0011] However, the technical problems to be solved by the embodiments of the present application are not limited to the above-mentioned technical problems, and there may be other technical problems.

[0012] Means used to solve problems

[0013] As a technical means for achieving the above-mentioned technical problem, a control method for an electric bicycle according to an embodiment of the present application may include the following steps: detecting the pedal speed and the wheel speed, applying the wheel speed parameter to the wheel speed instruction generated by multiplying the pedal speed by the gear ratio and the difference between the wheel speed to generate a wheel torque instruction, applying the pedal speed parameter to the wheel speed instruction and the difference between the wheel speed to generate a pedal torque instruction, controlling the motor based on the wheel torque instruction, and controlling the generator based on the pedal torque instruction.

[0014] In addition, the pedal torque command may be generated by a controller different from the controller that generates the wheel torque command.

[0015] In addition, the step of generating the wheel torque command may include the following steps: receiving the difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying the difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the wheel speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying it by an integral gain coefficient according to the wheel speed parameter to generate a first wheel torque value, differentiating the difference between the wheel speed command and the wheel speed and multiplying it by the wheel inertia moment to generate a second wheel torque value, and adding the first wheel torque value and the second wheel torque value to generate the wheel torque command.

[0016] Additionally, the proportional gain coefficient according to the wheel speed parameter may be proportional to the wheel moment of inertia.

[0017] Additionally, the wheel moment of inertia may be determined based on at least one of a weight of the electric bicycle, the number of motors, and a size of a wheel.

[0018] In addition, the step of generating the first wheel torque value may include the step of performing anti-windup control for limiting an output value by controlling an integrated value when integrating a difference between the wheel speed command and the wheel speed.

[0019] In addition, the step of controlling the motor may include the following steps: measuring the driving current of the motor, generating a wheel current command based on the wheel torque command, and generating a motor torque control current based on the difference between the wheel current command and the driving current of the motor and applying it to the motor.

[0020] In addition, the step of generating the pedal torque command may include the following steps: receiving the difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying the difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the pedal speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying it by an integral gain coefficient according to the pedal speed parameter to generate a first pedal torque value, differentiating the difference between the wheel speed command and the wheel speed and multiplying it by the pedal inertia moment to generate a second pedal torque value, and adding the first pedal torque value and the second pedal torque value and multiplying it by the assist ratio to generate the pedal torque command.

[0021] Additionally, the proportional gain coefficient according to the pedal speed parameter may be proportional to the pedal inertia moment.

[0022] Additionally, the pedal inertia moment may be determined based on characteristics of the pedals, regardless of the weight of the electric bicycle, the number of motors, or the size of the wheels.

[0023] In addition, the step of generating the first pedal torque value may be performed by controlling to continuously integrate a difference between the wheel speed command and the wheel speed.

[0024] In addition, the step of controlling the generator may include the following steps: measuring the driving current of the generator, generating a pedal current command based on the pedal torque command, and generating a generator torque control current based on the difference between the pedal current command and the driving current of the generator and applying it to the generator.

[0025] According to an embodiment of the present application, the control system of an electric bicycle may include: a pedal speed sensor for detecting pedal speed, a wheel speed sensor for detecting wheel speed, a motor current sensor for measuring the driving current of the motor, a generator current sensor for measuring the driving current of the generator, a controller for controlling the electric bicycle, a wheel actuator for controlling the motor, and a pedal actuator for controlling the generator; the controller includes: a wheel speed controller for applying a wheel speed parameter to a wheel speed instruction generated by multiplying the pedal speed by the gear ratio and the difference between the wheel speed to generate a wheel torque instruction, and a pedal speed controller for applying the pedal speed parameter to the difference between the wheel speed instruction and the wheel speed to generate a pedal torque instruction.

[0026] In addition, the wheel speed controller can receive the difference between the wheel speed command and the wheel speed, add a value obtained by multiplying the difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the wheel speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying it by an integral gain coefficient according to the wheel speed parameter to generate a first wheel torque value, differentiate the difference between the wheel speed command and the wheel speed and multiply it by the wheel inertia moment to generate a second wheel torque value, and add the first wheel torque value and the second wheel torque value to generate the wheel torque command.

[0027] In addition, the wheel speed controller may perform anti-windup control for limiting an output value by controlling an integrated value when integrating a difference between the wheel speed command and the wheel speed.

[0028] In addition, the pedal speed controller can receive the difference between the wheel speed command and the wheel speed, add a value obtained by multiplying the difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the pedal speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying it by an integral gain coefficient according to the pedal speed parameter to generate a first pedal torque value, differentiate the difference between the wheel speed command and the wheel speed and multiply it by the pedal inertia moment to generate a second pedal torque value, and add the first pedal torque value and the second pedal torque value and multiply it by the assist ratio to generate the pedal torque command.

[0029] Additionally, the pedal inertia moment may be determined based on characteristics of the pedals, regardless of the weight of the electric bicycle, the number of motors, or the size of the wheels.

[0030] In addition, the pedal speed controller may control to continuously integrate a difference between the wheel speed command and the wheel speed, thereby generating the first pedal torque value.

[0031] In addition, the controller may further include: a wheel torque controller that generates a wheel current command based on the wheel torque command generated by the wheel speed controller; and a pedal torque controller that generates a pedal current command based on the pedal torque command generated by the pedal speed controller.

[0032] In addition, the wheel actuator can control the motor by applying a motor torque control current generated based on the difference between the wheel current command and the measured drive current of the motor, and the pedal actuator can control the generator by applying a generator torque control current generated based on the difference between the pedal current command and the measured drive current of the generator.

[0033] The above-mentioned problem-solving means are merely exemplary and should not be construed as limiting the present application. In addition to the above-mentioned exemplary embodiments, additional embodiments may be present in the drawings and detailed description of the invention.

[0034] Effects of the Invention

[0035] According to the above-mentioned problem-solving means of the present application, a control method and system for an electric bicycle can be provided, wherein a pedal speed controller independent of a wheel speed controller is provided in a chainless electric bicycle, thereby enabling control using parameters suitable for each system.

[0036] In addition, according to the problem-solving means of the present application described above, a control method and system for an electric bicycle can be provided, which can provide the same pedal feel in a chainless electric bicycle regardless of the characteristics of the vehicle, and can improve the pedal sliding phenomenon caused by the weak reaction force of the pedal pushing the pedal away to improve the pedal feel.

[0037] However, the effects obtainable by the present application are not limited to the effects described above, and there may be other effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flowchart illustrating a method for controlling an electric bicycle according to an embodiment of the present application.

[0039] Figure 2A is a flowchart specifically illustrating the steps of generating a wheel torque command in a method for controlling an electric bicycle according to an embodiment of the present application. Figure 2B The flowchart specifically illustrates the steps of controlling the motor according to the wheel torque command in the control method of the electric bicycle according to one embodiment of the present application.

[0040] Figure 3A is a flowchart specifically illustrating the steps of generating a pedal torque command in a method for controlling an electric bicycle according to an embodiment of the present application. Figure 3B The flowchart specifically illustrates the steps of controlling a generator according to a pedal torque command in a method for controlling an electric bicycle according to an embodiment of the present application.

[0041] Figure 4 FIG. 1 is a control block diagram schematically illustrating a control system of an electric bicycle according to an embodiment of the present application.

[0042] Figure 5 FIG. 1 is a structural diagram schematically showing a structure of an electric bicycle including a control system of the electric bicycle according to an embodiment of the present application.

[0043] Figure 6 FIG. 1 is a diagram specifically illustrating a wheel speed controller and a pedal speed controller in a structure of an electric bicycle including a control system of the electric bicycle according to an embodiment of the present application.

[0044] Description of Reference Numerals

[0045] 100: Electric bicycle control system

[0046] 111: Wheel speed sensor

[0047] 112: Motor current sensor

[0048] 113: Pedal speed sensor

[0049] 114: Generator current sensor

[0050] 120: Controller

[0051] 121: Wheel speed controller

[0052] 122: Wheel torque controller

[0053] 123: Pedal speed controller

[0054] 124: Pedal torque controller

[0055] 130: Wheel actuator (WA)

[0056] 140: Pedal actuator (PA)

[0057] 200: Motor

[0058] 210: Wheel

[0059] 300: Generator

[0060] 310: Pedal DETAILED DESCRIPTION

[0061] Below, embodiments of the present application will be described in detail so that those skilled in the art can easily implement the present application with reference to the accompanying drawings. However, the present application can be embodied in many different forms and is not limited to the embodiments described herein. Furthermore, to clearly illustrate the present application in the accompanying drawings, portions not relevant to the description are omitted, and similar reference numerals are used throughout the specification to denote similar portions.

[0062] Throughout the specification of this application, when a part is referred to as being “connected” to another part, this includes not only the case of being “directly connected” but also the case of being “electrically connected” or “indirectly connected” with another element interposed therebetween.

[0063] Throughout the specification of this application, when it is stated that a certain component is located "on", "upper part", "upper end", "lower", "lower part" and "lower end" of another component, it not only includes the situation where the certain component is connected to another component, but also includes the situation where there is another component between the two components.

[0064] Throughout the specification of this application, when it is mentioned that a certain part "includes" a certain constituent element, unless there is a special description to the contrary, it means that other constituent elements are not excluded and other constituent elements may be included.

[0065] The present application relates to a control method and system for an electric bicycle, which can provide a stable pedal feel by controlling the pedal feel of a chainless electric bicycle by utilizing a pedal speed parameter suitable for a pedal system.

[0066] Figure 1 is a flowchart illustrating a method for controlling an electric bicycle according to an embodiment of the present application.

[0067] Reference Figure 1 The control method of an electric bicycle according to an embodiment of the present application may include a step S100 of detecting a pedal speed and a wheel speed. For example, the pedal speed may be detected by a pedal speed sensor, and the wheel speed may be detected by a wheel speed sensor.

[0068] Next, step S200 may be performed to apply the wheel speed parameter to the wheel speed command generated by multiplying the rotation speed of the pedal by the gear ratio and the difference between the wheel speeds to generate a wheel torque command.

[0069] In the step S200 of generating the wheel torque command, the wheel torque command is generated by using a prescribed wheel speed parameter. A specific embodiment of the step of generating the wheel torque command using the wheel speed parameter will be described in more detail in the description of FIG. 2 .

[0070] In addition, according to an embodiment of the present application, step S300 may be performed to apply the pedal speed parameter to the wheel speed command generated by multiplying the rotation speed of the pedal by the gear ratio and the difference between the wheel speeds to generate a pedal torque command.

[0071] In the step S300 of generating the pedal torque command, the pedal torque command is generated by using a predetermined pedal speed parameter. A specific embodiment of the step of generating the pedal torque command using the pedal speed parameter will be described in more detail in the description of FIG. 3 .

[0072] In addition, according to an embodiment of the present application, step S400 of controlling the motor based on the generated wheel torque command and step S500 of controlling the generator based on the generated pedal torque command may be performed.

[0073] According to the embodiment of the present application as described above, in an electric bicycle without a chain, a pedal torque command is generated by applying a pedal speed parameter that is independent of the wheel speed parameter to the difference between the wheel speed command and the wheel speed, thereby generating a pedal torque command that is most suitable for the control responsiveness of the pedal system of the electric bicycle, thereby exerting the effect of being able to produce a pedal feel.

[0074] Figure 2A This is a flowchart specifically illustrating the steps of generating a wheel torque command in a method for controlling an electric bicycle according to an embodiment of the present application.

[0075] Reference Figure 2A , step S200 of generating a wheel torque command may include: step S210, inputting a difference between the wheel speed command Nw* and the wheel speed Nw; step S220, adding a value obtained by multiplying the difference between the wheel speed command Nw* and the wheel speed Nw by a proportional gain coefficient Kp1 according to a wheel speed parameter and a value obtained by integrating the difference between the wheel speed command Nw* and the wheel speed Nw and multiplying it by an integral gain coefficient Ki1 according to the wheel speed parameter to generate a first wheel torque value T1*; step S230, differentiating the difference between the wheel speed command Nw* and the wheel speed Nw and multiplying it by the wheel inertia moment J1 to generate a second wheel torque value Ta1; and step S240, adding the first wheel torque value T1* and the second wheel torque value Ta1 to generate the wheel torque command Tw*.

[0076] The step of generating the wheel torque command may be performed by a Proportional-Integral-Differential (PID) controller.

[0077] The difference Nw*-Nw between the wheel speed command Nw* and the wheel speed Nw is also called an error. This error can be controlled so that it becomes 0, that is, the wheel speed follows the wheel speed command.

[0078] To this end, in step S210, the difference between the wheel speed command Nw* and the wheel speed Nw is received, and in step S220, a value obtained by multiplying the difference between the wheel speed command Nw* and the wheel speed Nw by a proportional gain coefficient Kp1 according to the wheel speed parameter and a value obtained by integrating the difference between the wheel speed command Nw* and the wheel speed Nw and multiplying it by an integral gain coefficient Ki1 according to the wheel speed parameter are added to generate a first wheel torque value T1*.

[0079] For example, the first wheel torque value T1* can be obtained by the following equation.

[0080] Equation 1

[0081]

[0082] The proportional gain coefficient Kp1 based on the wheel speed parameter can be proportional to the wheel moment of inertia J1. Alternatively, the proportional gain coefficient Kp1 based on the wheel speed parameter can be proportional to the vehicle acceleration frequency (a frequency suitable for the motor system). For example, the vehicle acceleration frequency (control bandwidth) can be approximately 0.1 to 0.35 Hz.

[0083] On the other hand, the wheel inertia moment J1 may have a value determined based on at least one of the weight of the electric bicycle, the number of motors, and the size of the wheels. For example, when the electric bicycle is heavier, the wheel inertia moment J1 may be larger, and thus the proportional gain coefficient Kp1 according to the wheel speed parameter may also have a larger value.

[0084] Furthermore, considering the characteristics of an electric bicycle, the proportional gain coefficient Kp1 and the integral gain coefficient Ki1, which are based on the wheel speed parameter, can have values that allow for a slow response speed (low response gain). By controlling the wheel speed using the proportional gain coefficient Kp1 and the integral gain coefficient Ki1 that enable this slow response speed, rapid acceleration of the electric bicycle can be suppressed, while achieving a smooth acceleration feel.

[0085] On the other hand, when generating first wheel torque value T1*, when integrating the difference between wheel speed command Nw* and wheel speed Nw, anti-windup control may be performed to limit the output value by controlling the integrated value.

[0086] When the error (the difference between the wheel speed command and the wheel speed) is continuously integrated, the accumulated error may transmit excessive force to the actuator, potentially causing vibration or unintended acceleration of the e-bike. Therefore, anti-windup control limits the output of the wheel actuator by controlling the integral value, reducing the accumulated error over time and effectively achieving stable riding of the e-bike.

[0087] Next, in step S230, the difference between the wheel speed command Nw* and the wheel speed Nw is differentiated and then multiplied by the wheel inertia moment J1 to generate a second wheel torque value Ta1. The second wheel torque value Ta1 thus calculated can be said to be a steering compensation torque caused by wheel acceleration.

[0088] For example, such a second wheel torque value Ta1 can be obtained by the following equation.

[0089] Equation 2

[0090] Ta1=(Nw * -Nw)d / dt×J1×gain1

[0091] That is, the steering compensation torque of the wheel can be obtained by differentiating the difference between the wheel speed command Nw* and the wheel speed Nw and then multiplying the difference by the wheel inertia moment J1 and the gain value gain1.

[0092] Then, the first wheel torque value T1* and the second wheel torque value Ta1 may be added together to generate a wheel torque command Tw* (step S240 ) and the motor may be controlled according to the wheel torque command Tw*.

[0093] Figure 2B The flowchart specifically illustrates the steps of controlling the motor according to the wheel torque command in the control method of the electric bicycle according to one embodiment of the present application.

[0094] Reference Figure 2B , step S400 of controlling the motor may include: step S410, measuring the driving current of the motor; step S420, generating a wheel current command iw* based on the wheel torque command Tw*; and step S430, generating and applying the motor torque control current iw based on the difference between the wheel current command iw* and the driving current of the motor.

[0095] Here, the measurement of the driving current of the motor can be performed by a motor current sensor, and the wheel current command iw* for driving the motor is calculated according to the wheel torque command Tw* generated in the above step S200, and the motor torque control current iw is applied so that the driving current of the motor follows the wheel current command iw*, thereby controlling the motor.

[0096] Figure 3A This is a flowchart specifically illustrating the steps of generating a pedal torque command in a method for controlling an electric bicycle according to an embodiment of the present application.

[0097] Reference Figure 3A , step S300 of generating a pedal torque command may include: step S310, inputting the difference between the wheel speed command Nw* and the wheel speed Nw; step S320, adding a value obtained by multiplying the difference between the wheel speed command Nw* and the wheel speed Nw by a proportional gain coefficient Kp2 according to a pedal speed parameter and a value obtained by integrating the difference between the wheel speed command Nw* and the wheel speed Nw and multiplying it by an integral gain coefficient Ki2 according to the pedal speed parameter to generate a first pedal torque value T2*; step S330, after differentiating the difference between the wheel speed command Nw* and the wheel speed Nw, multiplying it by the pedal inertia moment J2 to generate a second pedal torque value Ta2; and step S340, after adding the first pedal torque value T2* and the second pedal torque value Ta2, multiplying it by the assist ratio AL to generate a pedal torque command Tp*.

[0098] This step of generating a pedal torque command may also be performed by a proportional-integral-derivative controller.

[0099] First, in step S310, the difference between the wheel speed command Nw* and the wheel speed Nw is received, and in step S320, the value obtained by multiplying the difference Nw*-Nw between the wheel speed command Nw* and the wheel speed Nw by the proportional gain coefficient Kp2 according to the pedal speed parameter and the value obtained by integrating the difference Nw*-Nw between the wheel speed command Nw* and the wheel speed Nw and multiplying it by the integral gain coefficient Ki2 according to the pedal speed parameter are added to generate a first pedal torque value T2*.

[0100] Here, the proportional gain coefficient Kp2 based on the pedal speed parameter is a value independent of the proportional gain coefficient Kp1 based on the wheel speed parameter, and the integral gain coefficient Ki2 based on the pedal speed parameter is also a value independent of the integral gain parameter Ki1 based on the wheel speed parameter, and can be a parameter suitable for each pedal system.

[0101] For example, the first pedal torque value T2* can be obtained by the following equation.

[0102] Equation 3

[0103]

[0104] The proportional gain coefficient Kp2 based on the pedal speed parameter can be proportional to the pedal inertia moment J2. Alternatively, the proportional gain coefficient Kp2 based on the pedal speed parameter can be proportional to the pedal feel frequency (a frequency suitable for the pedal system). For example, the pedal feel frequency (control bandwidth) can be approximately 0.3 to 0.5 Hz.

[0105] On the other hand, the pedal inertia moment J2 can be determined based on the characteristics of the pedal (the inertia of the pedal itself) without regard to the weight of the electric bicycle, the number of motors, or the size of the wheels.

[0106] Furthermore, taking into account the characteristics of the pedal system, the proportional gain coefficient Kp2 and the integral gain coefficient Ki2, based on the pedal speed parameter, can have values that allow for a high response speed (high response gain). Specifically, Kp2 can have a value greater than Kp1, and Ki2 can have a value greater than Ki1. By controlling the pedal speed based on the proportional gain coefficient Kp2 and the integral gain coefficient Ki2 that enable this high response speed, a pedal feel suitable for the pedal system can be generated, comparable to that of a bicycle with a chain.

[0107] On the other hand, in the step of generating the first pedal torque value T2*, unlike the step of generating the first wheel torque value, anti-windup control is not performed, and control may be performed to continuously integrate the difference between the wheel speed command and the wheel speed.

[0108] As described above, when generating a pedal torque command, unlike when generating a wheel torque command, anti-saturation control is not performed and integration is continued (error accumulation is continued), thereby preventing the phenomenon of the pedal being pushed away when being pressed hard due to weak pedal reaction force (pedal slip-through phenomenon), thereby achieving the effect of generating a pedal feel that is more similar to that of a bicycle with a chain.

[0109] On the other hand, for example, when the error value, which is the difference between the wheel speed command and the wheel speed, is less than 0 (Nw* - Nw < 0), initializing the integrated cumulative error can prevent overshoot. This prevents unwanted pedal feel when the pedals are rotated slowly, thus suppressing the side effects of continuous integration.

[0110] Next, in step S330, after differentiating the difference between the wheel speed command Nw* and the wheel speed Nw, it is multiplied by the pedal inertia moment J2 to generate a second pedal torque value Ta2. The second pedal torque value Ta2 calculated as described above can be said to be a steering compensation torque caused by the pedal acceleration.

[0111] For example, such a second pedal torque value Ta2 can be obtained by the following equation.

[0112] Equation 4

[0113] Ta2=(Nw * -Nw)d / dt×J2×gain2

[0114] That is, the steering compensation torque of the pedal can be obtained by differentiating the difference between the wheel speed command Nw* and the wheel speed Nw and then multiplying the difference by the pedal inertia moment J2 and the gain value gain2.

[0115] Then, the first pedal torque value T2* and the second pedal torque value Ta2 are added together and multiplied by the assist ratio AL to generate a pedal torque command Tp* (step S340). This assist ratio (or assist level) is a configurable value. Depending on the configured assist ratio, the pedal torque command Tp* is made greater or less than the value T2*+Ta2 calculated based on the pedal speed parameter, thereby adjusting the pedal feel to be lighter or heavier according to the user's intention.

[0116] Figure 3B The flowchart specifically illustrates the steps of controlling a generator according to a pedal torque command in a control method of an electric bicycle according to an embodiment of the present application.

[0117] Reference Figure 3B , step S500 of controlling the generator may include: step S510, measuring the driving current of the generator; step S520, generating a pedal current command ip* based on the pedal torque command Tp*; and step S530, generating and applying the generator torque control current ip based on the difference between the pedal current command ip* and the driving current of the generator.

[0118] Here, the measurement of the driving current of the generator can be performed by a generator current sensor, and the pedal current command ip* for driving the generator is calculated according to the pedal torque command Tp* generated in the above step S300, and the generator torque control current ip is applied so that the driving current of the generator follows the pedal current command ip*, thereby controlling the generator.

[0119] According to the embodiment of the present application as described above, when generating a pedal torque instruction, the pedal torque instruction is generated based on a pedal speed parameter that is independent of the wheel speed parameter, so that a pedal torque instruction independent of the wheel torque instruction can be generated, thereby achieving a significant effect of generating a pedal feel suitable for the pedal system.

[0120] Figure 4 FIG. 1 is a control block diagram schematically illustrating a control system of an electric bicycle according to an embodiment of the present application.

[0121] in addition, Figure 5 Schematically shows the structure of an electric bicycle including a control system of the electric bicycle according to an embodiment of the present application. Figure 5 In the figure, Np represents the pedal speed, GR represents the gear ratio, Nw represents the wheel speed, Nw* represents the wheel speed command, Tw* represents the wheel torque command, Tp* represents the pedal torque command, AL represents the assist ratio, iw* represents the wheel current command, iw represents the motor torque control current, ip* represents the pedal current command, and ip represents the generator torque control current.

[0122] like Figure 4 and Figure 5 As shown, the control system 100 of the electric bicycle according to an embodiment of the present application may include: a wheel speed sensor 111 for detecting the wheel speed; a motor current sensor 112 for measuring the driving current of the motor; a pedal speed sensor 113 for detecting the pedal speed; a generator current sensor 114 for measuring the driving current of the generator; a controller 120 for controlling the electric bicycle; a wheel actuator (WA) 130 for controlling the motor 200; and a pedal actuator (PA) 140 for controlling the generator 300.

[0123] In addition, the controller 120 may include: a wheel speed controller 121, which generates a wheel torque command Tw* by applying a wheel speed parameter to a wheel speed command Nw* generated by multiplying the pedal speed Np by the gear ratio GR and the difference between the wheel speed Nw; and a pedal speed controller 123, which generates a pedal torque command Tp* by applying the pedal speed parameter to the difference between the wheel speed command Nw* and the wheel speed Nw.

[0124] In addition, the controller 120 may include: a wheel torque controller 122 that generates a wheel current command iw* based on the wheel torque command Tw* generated by the wheel speed controller 121; and a pedal torque controller 124 that generates a pedal current command ip* based on the pedal torque command Tp* generated by the pedal speed controller 123.

[0125] On the other hand, a wheel actuator (WA) 130 controls the motor 200 by applying a motor torque control current iw generated based on the difference between a wheel current command iw* and a measured motor drive current, thereby rotating a wheel 210 mechanically connected to the motor 200 .

[0126] In addition, the pedal actuator (PA) 140 controls the generator 300 by applying a generator torque control current ip generated based on the difference between the pedal current command ip* and the measured generator drive current, thereby controlling the pedal feel of the pedal (ePedal) 310 .

[0127] According to the control system 100 of the electric bicycle having the structure as described above, in the pedal speed controller 123 independent of the wheel speed controller 121, the pedal feel is controlled using a pedal speed parameter suitable for the pedal system, thereby achieving the effect of providing the same pedal feel regardless of the characteristics of the vehicle (weight, wheel size, number of motors, type of motor, etc.).

[0128] Figure 6 FIG. 1 is a diagram specifically illustrating a wheel speed controller and a pedal speed controller in a structure of an electric bicycle including a control system of the electric bicycle according to an embodiment of the present application.

[0129] like Figure 6 As shown, the wheel speed controller 121 and the pedal speed controller 123 according to the embodiment of the present application may be PID controllers (Proportional-Integral-Derivative controllers).

[0130] As described above, the wheel speed controller 121 can receive the difference Nw*-Nw between the wheel speed command and the wheel speed, add a value obtained by multiplying the difference Nw*-Nw between the wheel speed command and the wheel speed by a proportional gain coefficient Kp1 according to the wheel speed parameter and a value obtained by integrating the difference Nw*-Nw between the wheel speed command and the wheel speed and multiplying it by an integral gain coefficient Ki1 according to the wheel speed parameter to generate a first wheel torque value T1*, differentiate the difference Nw*-Nw between the wheel speed command and the wheel speed and multiply it by the wheel inertia moment J1 to generate a second wheel torque value Ta1, and add the first wheel torque value T1* and the second wheel torque value Ta1 to generate the wheel torque command Tw*.

[0131] Here, the wheel inertia moment J1 may be determined based on at least one of the weight of the electric bicycle, the number of motors, and the size of the wheels.

[0132] In addition, the wheel speed controller 121 also includes anti-windup (AW) control, and can perform control to limit the output value by controlling the integrated value when integrating the difference Nw*-Nw between the wheel speed command and the wheel speed.

[0133] In addition, the pedal speed controller 123 can receive the difference Nw*-Nw between the wheel speed command and the wheel speed, add a value obtained by multiplying the difference Nw*-Nw between the wheel speed command and the wheel speed by the proportional gain coefficient Kp2 according to the pedal speed parameter and a value obtained by integrating the difference Nw*-Nw between the wheel speed command and the wheel speed and multiplying it by the integral gain coefficient Ki2 according to the pedal speed parameter to generate a first pedal torque value T2*, after differentiating the difference Nw*-Nw between the wheel speed command and the wheel speed, multiply it by the pedal inertia moment J2 to generate a second pedal torque value Ta2; and after adding the first pedal torque value T2* and the second pedal torque value Ta2, multiply it by the assist ratio AL to generate the pedal torque command Tp*.

[0134] Here, the pedal inertia moment J2 can be determined based on the characteristics of the pedals, regardless of the weight of the electric bicycle, the number of motors, or the size of the wheels.

[0135] In addition, the pedal speed controller 123 may continuously integrate the difference Nw*-Nw between the wheel speed command and the wheel speed to generate the first pedal torque value T2*. As described above, by reducing the phenomenon of the pedal being pushed when the pedal is pressed hard, the pedal feel can be improved.

[0136] However, when the difference Nw*-Nw between the wheel speed command and the wheel speed is smaller than 0, overshoot can also be prevented by initializing the integration value.

[0137] According to the embodiment of the present application as described above, the wheel speed controller 121 and the pedal speed controller 123 of the electric bicycle are controlled to apply different parameters to the same input value Nw*-Nw, generating a torque instruction (wheel torque instruction or pedal torque instruction) suitable for each system (motor system or pedal system), thereby achieving the effect of being able to perform control that best suits the performance of each system.

[0138] As described above, according to the embodiments of the present application, a control method and system for an electric bicycle can be provided, which generates a pedal torque instruction by utilizing pedal parameters suitable for the pedal system to generate a pedal feel similar to that of a bicycle with a chain, while preventing the pedal slip-through phenomenon, thereby forming a more stable pedal feel.

[0139] In addition, according to an embodiment of the present application, by utilizing a pedal speed controller independent of a wheel speed controller to generate a pedal torque command, it is possible to provide the same pedal feel regardless of factors such as the weight of the electric bicycle, the size of the wheels, the number of motors, the type of motors, etc., and the pedal feel can be adjusted differently according to the driver's preferences.

[0140] The above description of the present application is for illustrative purposes only. Those skilled in the art will appreciate that the present application can be easily modified into other specific forms without changing the technical concept or essential features of the present application. Therefore, it should be understood that the above embodiments are exemplary and not restrictive in all respects. For example, components described as a single type can be implemented in a distributed manner, and similarly, components described as distributed can also be implemented in a combined manner.

[0141] The scope of the present application is indicated by the claims described later rather than the detailed description above, and should be construed as including all variations or modifications derived from the meaning and scope of the claims and their equivalent concepts within the scope of the present application.

Claims

1. A control method for an electric bicycle, characterized in that: The steps include: Detect pedal speed and wheel speed, applying a wheel speed parameter to a wheel speed command generated by multiplying the pedal speed by a gear ratio and a difference between the wheel speeds to generate a wheel torque command, applying a pedal speed parameter to the difference between the wheel speed command and the wheel speed to generate a pedal torque command, controlling the motor based on the wheel torque command, and The generator is controlled based on the pedal torque command.

2. The control method of the electric bicycle according to claim 1, characterized in that: The pedal torque command is generated by a controller different from a controller that generates the wheel torque command.

3. The control method of the electric bicycle according to claim 1, characterized in that: The step of generating the wheel torque command comprises the following steps: receiving a difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying a difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the wheel speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying the result by an integral gain coefficient according to the wheel speed parameter to generate a first wheel torque value, Differentiating the difference between the wheel speed command and the wheel speed and multiplying the result by the wheel moment of inertia to generate a second wheel torque value, and The first wheel torque value and the second wheel torque value are added to generate the wheel torque command.

4. The control method of the electric bicycle according to claim 3, characterized in that: The proportional gain coefficient according to the wheel speed parameter is proportional to the wheel moment of inertia.

5. The control method of the electric bicycle according to claim 4, characterized in that: The wheel moment of inertia is determined based on at least one of a weight of the electric bicycle, a number of motors, and a size of a wheel.

6. The control method of the electric bicycle according to claim 3, characterized in that: The step of generating the first wheel torque value comprises the following steps: When integrating the difference between the wheel speed command and the wheel speed, anti-windup control is performed to limit the output value by controlling the integrated value.

7. The control method of an electric bicycle according to any one of claims 1 to 6, characterized in that: The step of controlling the motor comprises the following steps: measuring the driving current of the motor, generating a wheel current command based on the wheel torque command, and A motor torque control current is generated based on a difference between the wheel current command and the drive current of the motor and applied to the motor.

8. The control method of the electric bicycle according to claim 1, characterized in that: The step of generating the pedal torque command comprises the following steps: receiving a difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying a difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the pedal speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying the result by an integral gain coefficient according to the pedal speed parameter to generate a first pedal torque value, Differentiating the difference between the wheel speed command and the wheel speed and multiplying the result by the pedal inertia moment to generate a second pedal torque value, and The first pedal torque value and the second pedal torque value are added and then multiplied by an assist ratio to generate the pedal torque command.

9. The control method of the electric bicycle according to claim 8, characterized in that: The proportional gain coefficient according to the pedal speed parameter is proportional to the pedal inertia moment.

10. The control method of the electric bicycle according to claim 9, characterized in that: The pedal inertia moment is determined based on the characteristics of the pedals and is independent of the weight of the electric bicycle, the number of motors, or the size of the wheels.

11. The control method of the electric bicycle according to claim 8, characterized in that: The step of generating the first pedal torque value is performed by controlling to continuously integrate a difference between the wheel speed command and the wheel speed.

12. The control method for an electric bicycle according to any one of claims 1 to 6 and 8 to 11, characterized in that: The step of controlling the generator comprises the following steps: measuring the driving current of the generator, generating a pedal current command based on the pedal torque command, and A generator torque control current is generated based on a difference between the pedal current command and the drive current of the generator and applied to the generator.

13. A control system for an electric bicycle, characterized in that: include: Pedal speed sensor, detects pedal speed, Wheel speed sensor, detects wheel speed, Motor current sensor, measures the motor drive current, Generator current sensor, measuring the driving current of the generator, A controller for controlling the electric bicycle, wheel actuators for controlling the motors, and a pedal actuator for controlling the generator; The controller includes: a wheel speed controller that applies a wheel speed parameter to a wheel speed command generated by multiplying the pedal speed by a gear ratio and a difference between the wheel speeds to generate a wheel torque command, and A pedal speed controller applies a pedal speed parameter to the wheel speed command and a difference between the wheel speeds to generate a pedal torque command.

14. The control system of the electric bicycle according to claim 13, characterized in that: the wheel speed controller, receiving a difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying a difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the wheel speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying the result by an integral gain coefficient according to the wheel speed parameter to generate a first wheel torque value, Differentiating the difference between the wheel speed command and the wheel speed and multiplying the result by the wheel moment of inertia to generate a second wheel torque value, and The first wheel torque value and the second wheel torque value are added to generate the wheel torque command.

15. The control system of the electric bicycle according to claim 14, characterized in that: the wheel speed controller, When integrating the difference between the wheel speed command and the wheel speed, anti-windup control is performed to limit the output value by controlling the integrated value.

16. The control system of the electric bicycle according to claim 13, characterized in that: the pedal speed controller, receiving a difference between the wheel speed command and the wheel speed, adding a value obtained by multiplying a difference between the wheel speed command and the wheel speed by a proportional gain coefficient according to the pedal speed parameter and a value obtained by integrating the difference between the wheel speed command and the wheel speed and multiplying the result by an integral gain coefficient according to the pedal speed parameter to generate a first pedal torque value, Differentiating the difference between the wheel speed command and the wheel speed and multiplying the result by the pedal inertia moment to generate a second pedal torque value, and The first pedal torque value and the second pedal torque value are added and then multiplied by an assist ratio to generate the pedal torque command.

17. The control system of the electric bicycle according to claim 16, characterized in that: The pedal inertia moment is determined based on the characteristics of the pedals and is independent of the weight of the electric bicycle, the number of motors, or the size of the wheels.

18. The control system of the electric bicycle according to claim 16, characterized in that: The pedal speed controller controls to continuously integrate a difference between the wheel speed command and the wheel speed, thereby generating the first pedal torque value.

19. The control system of an electric bicycle according to any one of claims 13 to 18, characterized in that: The controller further includes: a wheel torque controller that generates a wheel current command based on the wheel torque command generated by the wheel speed controller; and A pedal torque controller generates a pedal current command based on the pedal torque command generated by the pedal speed controller.

20. The control system of the electric bicycle according to claim 19, characterized in that: the wheel actuator controls the motor by applying a motor torque control current generated based on a difference between the wheel current command and a measured drive current of the motor, The pedal actuator controls the generator by applying a generator torque control current generated based on a difference between the pedal current command and a measured drive current of the generator.

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