Method and system for controlling electric bicycle

Abstract

A control method and control system for an electric bicycle are disclosed. A control method for an electric bicycle according to one embodiment of the present invention is characterized by comprising: a step of detecting the rotational speed of a pedal and the speed of a wheel; a step of measuring the driving current of a motor driving the wheel and the driving current of a generator driven by the pedal; and a step of generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal.

Description

Technology Field

[0001] The present invention relates to a control method and a control system for an electric bicycle. More specifically, the invention relates to a control method and a control system for an electric bicycle capable of adjusting the pedal feel to produce a light pedal feel regardless of riding conditions in a chainless electric bicycle. Background Technology

[0002] Electric bicycles (including e-cargo bikes) use electricity to power a motor, either to assist human power or to drive the vehicle. The method where the motor assists the rider in pedaling to drive the wheels is called the PAS (Pedal Assistance System), while the method where the wheels are driven solely by the motor's power by pulling a handle is called the Throttle method. Additionally, there are electric bicycles that support both PAS and Throttle modes.

[0003] Generally, chainless electric bicycles recognize the speed at which the user rotates the pedals and control the motor speed in proportion to that speed. Since the pedals are not connected to a chain and therefore do not carry a load, a generator connected to the pedals is controlled to create the same pedal load sensation as a bicycle with a chain. By controlling the pedal load according to the electric bicycle's speed, the user can experience a pedaling sensation similar to that of a bicycle with a chain.

[0004] However, in conventional technology for generating pedal feel, motor torque is generated by rotating the pedal, and pedal feel is generated based on the motor torque.

[0005] According to this method, the pedal feel is controlled to become heavy when the pedal's rotational speed is greater than the motor's speed, and light when the pedal's rotational speed is less than the motor's speed.

[0006] This is intended to provide a pedaling sensation similar to that of a bicycle with actual pedals in chainless electric bicycles.

[0007] However, when pedal feel is formed based on motor speed in this way, there is a problem in that the rider feels a heavy pedal sensation, for example when the electric bicycle is climbing a hill or when the electric bicycle is loaded with a heavy load, and thus easily feels fatigued.

[0008] Therefore, there is a need for a control method and control system for an electric bicycle that can control pedal feel to reduce driver fatigue in chainless electric bicycles. The problem to be solved

[0009] The present invention aims to solve the problems of the aforementioned conventional technology by providing a control method and a control system for an electric bicycle that can adjust pedal feel regardless of driving conditions to reduce driver fatigue.

[0010] However, the technical problems that the embodiments of the present invention aim to solve are not limited to the technical problems described above, and other technical problems may exist. means of solving the problem

[0011] As a technical means for achieving the above-mentioned technical problem, a control method for an electric bicycle according to one embodiment of the present invention is characterized by comprising: a step of detecting the rotational speed of a pedal and the speed of a wheel; a step of measuring the driving current of a motor driving the wheel and the driving current of a generator driven by the pedal; and a step of generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal.

[0012] In addition, the step of generating the pedal torque command may generate the pedal torque command such that a pedal torque proportional to the rotational speed of the pedal is generated.

[0013] Additionally, the control method of the electric bicycle may further include the step of generating a pedal torque control current for controlling the pedal torque based on the generated pedal torque command and the measured driving current of the generator; and the step of controlling the current supplied to the generator based on the generated pedal torque control current.

[0014] Additionally, the control method of the electric bicycle may further include the step of generating a wheel torque command based on the wheel speed and the wheel speed, which is obtained by multiplying the rotational speed of the pedal by a gear ratio; the step of generating a wheel torque control current for controlling the wheel torque based on the generated wheel torque command and the measured driving current of the motor; and the step of controlling the current supplied to the motor based on the generated wheel torque control current.

[0015] A control system for an electric bicycle according to an embodiment of the present invention comprises at least one control unit, and is characterized by including: at least one speed sensor unit for detecting the rotational speed of a pedal and the speed of a wheel; at least one current sensor unit for measuring the driving current of a motor driving the wheel and the driving current of a generator driven by the pedal; and a pedal feel control unit for generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal.

[0016] In addition, the pedal feel control unit can generate the pedal torque command so that a pedal torque proportional to the rotational speed of the pedal is generated.

[0017] In addition, the control system of the electric bicycle may further include a pedal torque control unit that generates a pedal torque control current for controlling the pedal torque based on the generated pedal torque command and the measured generator driving current.

[0018] In addition, the control system of the electric bicycle further includes a pedal actuator for driving a generator, and can control the pedal torque by supplying the generated pedal torque control current to the pedal actuator to control the current flowing to the generator.

[0019] Additionally, the control system of the electric bicycle may further include a wheel speed control unit that generates a wheel torque command based on the speed of the wheel and a wheel speed command obtained by multiplying the rotational speed of the pedal by a gear ratio; and a wheel torque control unit that generates a wheel torque control current for controlling the wheel torque based on the generated wheel torque command and the measured driving current of the motor.

[0020] In addition, the control system of the electric bicycle further includes a wheel actuator for driving a motor, and can control the wheel torque by supplying the generated wheel torque control current to the wheel actuator to control the current flowing to the motor.

[0021] The means for solving the problem described above are merely exemplary and should not be interpreted as intended to limit the present invention. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and the detailed description of the invention. Effects of the invention

[0022] According to the means for solving the problem of the present invention described above, a control method and a control system for an electric bicycle can be provided that can reduce driver fatigue by providing a light pedaling sensation regardless of road conditions or the weight of the electric bicycle in a chainless electric bicycle.

[0023] However, the effects obtainable from this invention are not limited to those described above, and other effects may exist. Brief explanation of the drawing

[0024] FIG. 1 is a flowchart illustrating a control method for an electric bicycle according to one embodiment of the present invention. FIG. 2 is a flowchart specifically illustrating a wheel torque control method in a control method for an electric bicycle according to one embodiment of the present invention. FIG. 3 is a diagram schematically showing the relationship between pedal speed and pedal feel when an electric bicycle is climbing an uphill road in a control method for an electric bicycle according to one embodiment of the present invention. FIG. 4 is a control block diagram schematically showing a control system of an electric bicycle according to one embodiment of the present invention. FIG. 5 is a schematic diagram showing the structure of an electric bicycle including a control system for an electric bicycle according to one embodiment of the present invention. Specific details for implementing the invention

[0025] Embodiments of the present invention are described below with reference to the attached drawings to enable those skilled in the art to easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0026] Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "electrically connected" or "indirectly connected" with other elements interposed between them.

[0027] Throughout the entire specification, when a component is described as being located "on," "on top," "on top," "under," "on bottom," or "on bottom" of another component, this includes not only cases where the component is in contact with the other component but also cases where another component exists between the two components.

[0028] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0029] The present invention relates to a control method and control system for an electric bicycle that can provide a light pedaling sensation regardless of road conditions or the weight of the electric bicycle.

[0030] FIG. 1 is a flowchart illustrating a control method for an electric bicycle according to one embodiment of the present invention. FIG. 2 is a flowchart specifically illustrating a wheel torque control method in a control method for an electric bicycle according to one embodiment of the present invention.

[0031] Referring to FIG. 1, a control method for an electric bicycle according to one embodiment of the present invention may include a step (S100) of detecting the rotational speed of a pedal and the speed of a wheel, a step (S200) of measuring the driving current of a motor driving the wheel and the driving current of a generator driven by the pedal, and a step (S300) of generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal.

[0032] The rotational speed of the pedal driven by the driver can be detected by a generator speed sensor (pedal speed sensor) equipped in the vehicle's generator (also called ePedal), and the speed of the wheel can be detected by a motor speed sensor (wheel speed sensor) equipped in the vehicle's motor.

[0033] In addition, the driving current of the motor driving the wheel and the driving current of the generator driven by the pedal can be measured by the motor current sensor and the generator current sensor, respectively.

[0034] Meanwhile, a control method for an electric bicycle according to one embodiment of the present invention may include a step (S300) of generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal.

[0035] Additionally, the step (S300) of generating the pedal torque command can generate a pedal torque command such that a pedal torque proportional to the rotational speed of the pedal is generated. That is, the pedal feel can be controlled so that the faster the rotational speed of the pedal, the heavier the pedal feel becomes, and the slower the rotational speed of the pedal, the lighter the pedal feel becomes.

[0036] In addition, a control method for an electric bicycle according to one embodiment of the present invention may further include a step (S400) of generating a pedal torque control current for controlling the pedal torque based on a generated pedal torque command and a measured driving current of a generator, and a step (S500) of controlling the current supplied to the generator based on the generated pedal torque control current.

[0037] That is, in the step (S400) of generating pedal torque control current, based on a pedal torque command that generates a pedal sensation proportional to the pedal rotation speed, a control current can be generated to apply additional power in the current direction of rotation of the generator, or a control current can be generated to apply a force in the opposite direction to the current direction of rotation of the generator.

[0038] Meanwhile, in the current control step (S500), the generated pedal torque control current is supplied to the generator, thereby controlling the current flowing through the generator, and accordingly, the pedal torque can be controlled.

[0039] According to conventional technology, pedal feel is generated based on the motor torque, whereas according to the embodiment of the present invention, since a pedal torque command is generated to adjust the pedal feel based on the rotational speed of the pedal, pedal feel can be generated independently of the motor torque solely by the rotational speed of the pedal. Therefore, for example, when an electric bicycle is climbing a hill or when the electric bicycle is loaded with a heavy load, an effect can be achieved in which the driver can feel a lighter pedal feel.

[0040] Meanwhile, referring to FIG. 2, after the step of detecting the rotational speed of the pedal and the speed of the wheel (S100) and the step of measuring the driving current of the motor and the driving current of the generator (S200), the step of generating a wheel torque command based on the wheel speed command and the speed of the wheel (S310) may be performed. Here, the wheel speed command may correspond to the rotational speed of the pedal multiplied by the gear ratio.

[0041] Next, a step (S410) of generating a wheel torque control current for controlling the wheel torque based on the generated wheel torque command and the measured driving current of the motor, and a step (S510) of controlling the current supplied to the motor based on the generated wheel torque control current may be performed.

[0042] Specifically, in the step of generating wheel torque control current (S410), based on the generated wheel torque command, a control current may be generated to apply additional power in the current motor's rotational direction, or a control current may be generated to apply a force in the opposite direction to the current motor's rotational direction.

[0043] Meanwhile, in the current control step (S510), the generated wheel torque control current is supplied to the generator, thereby controlling the current flowing through the generator and, accordingly, the wheel torque can be controlled.

[0044] According to the control method of an electric bicycle according to one embodiment of the present invention as described above, compared to the control method of an electric bicycle according to the prior art which generates a pedaling sensation similar to that of a bicycle with a chain, a significant effect can be achieved in that it provides a light pedaling sensation so that the driver feels less fatigue when climbing uphill or riding with a heavy load.

[0045] FIG. 3 is a diagram schematically showing the relationship between pedal speed and pedal feel when an electric bicycle is climbing an uphill road in a control method for an electric bicycle according to one embodiment of the present invention.

[0046] As previously explained, according to the control method of an electric bicycle according to one embodiment of the present invention, a pedal sensation can be generated in proportion to the rotational speed of the pedals regardless of whether the angle of inclination of the ground increases (i.e., when climbing uphill).

[0047] Therefore, as shown in Fig. 3, even when the angle of inclination of the ground increases while riding the electric bicycle, the pedal feel (pedal torque) can be controlled by adjusting the rotational speed of the pedal, and thus, even when climbing a slope, a light pedal feel can be generated depending on the pedal rotational speed.

[0048] FIG. 4 is a control block diagram schematically illustrating a control system of an electric bicycle according to one embodiment of the present invention. FIG. 5 is a structural diagram schematically illustrating the structure of an electric bicycle including a control system of an electric bicycle according to one embodiment of the present invention.

[0049] As shown in FIG. 4, a control system (100) of an electric bicycle according to one embodiment of the present invention may include sensors such as a motor position sensor (111), a motor speed sensor (112), a motor current sensor (113), a generator position sensor (114), a generator speed sensor (115), and a generator current sensor (116).

[0050] The motor position sensor (111) detects the rotational position of the motor, the motor speed sensor (112) detects the speed of the motor (wheel), and the motor current sensor (113) can detect the driving current flowing through the motor. Additionally, the generator position sensor (114) detects the rotational position of the generator (pedal), the generator speed sensor (115) detects the rotational speed of the generator (pedal), and the generator current sensor (116) can detect the driving current flowing through the generator. The motor speed sensor (112) and the generator speed sensor (115) may be referred to as the speed sensor section, and the motor current sensor (113) and the generator current sensor (116) may be referred to as the current sensor section.

[0051] Meanwhile, a control system (100) of an electric bicycle according to one embodiment of the present invention may include a controller (120) for controlling the system. This controller (120) may include a wheel speed control unit (121), a wheel torque control unit (122), a pedal feel control unit (123), and a pedal torque control unit (124).

[0052] Additionally, the controller (120) can be connected to the wheel actuator (130) and the pedal actuator (140), respectively, to control the motor (200) and the generator (300).

[0053] Below, we will examine the configuration of the controller (120) in more detail with reference to FIG. 5. In FIG. 5, Np represents the rotational speed of the pedal, Nw represents the speed of the wheel, Nw* represents the wheel speed command, Tp* represents the pedal torque command, Tw* represents the wheel torque command, and GR represents the gear ratio.

[0054] Referring to FIG. 5, the wheel speed control unit (121) of the controller (120) receives a wheel speed command (Nw*), which is the value obtained by multiplying the rotational speed (Np) of the pedal detected by the generator speed sensor (115) by the gear ratio (GR), and generates a wheel torque command (Tw*) based on the received wheel speed command (Nw*) and the speed (Nw) of the wheel detected by the motor speed sensor (112) and transmits it to the wheel torque control unit (122).

[0055] Specifically, the wheel speed control unit (121) can generate a wheel torque command (Tw*) to increase the wheel speed (Nw) when the wheel speed command (Nw*) is greater than the wheel speed (Nw) detected by the motor speed sensor (112), and generate a wheel torque command (Tw*) to decrease the wheel speed (Nw) when the wheel speed command (Nw*) is less than the wheel speed (Nw) detected by the actual motor speed sensor (112), and transmit it to the wheel torque control unit (122).

[0056] The wheel torque control unit (122) receives a wheel torque command (Tw*) and can generate a wheel torque control current for controlling the wheel torque based on the received wheel torque command (Tw*) and the driving current of the motor detected by the motor current sensor (113).

[0057] The wheel torque can be controlled by controlling the current flowing through the motor (200) by supplying the wheel torque control current generated in this way to the wheel actuator (WA: Wheel Actuator) (130). The motor (200) may be mechanically connected to the wheel (210) of the electric bicycle so that the wheel (210) rotates according to the rotation of the motor.

[0058] Additionally, the pedal feel control unit (123) of the controller (120) can generate a pedal torque command (Tp*) to adjust the pedal feel based on the rotational speed (Np) of the pedal, and transmit the generated pedal torque command (Tp*) to the pedal torque control unit (124).

[0059] Specifically, the pedal feel control unit (123) can generate a pedal torque command (Tp*) such that a pedal torque proportional to the rotational speed (Np) of the pedal detected by the generator speed sensor (115) is generated. That is, the pedal torque command (Tp*) can be generated so that the pedal feel becomes heavy when the rotational speed (Np) of the pedal is fast, and the pedal feel becomes light when the rotational speed (Np) of the pedal is slow.

[0060] Additionally, the pedal torque control unit (124) can receive a pedal torque command (Tp*) and generate a pedal torque control current to control the pedal torque based on the received pedal torque command (Tp*) and the generator driving current detected by the generator current sensor (116).

[0061] The pedal torque can be controlled by controlling the current flowing through the generator (300) by supplying the pedal torque control current generated in this way to the pedal actuator (PA: Pedal Actuator) (140). The generator (300) is mechanically connected to the pedal (310) of the electric bicycle, and the pedal feel can be controlled by controlling the torque of the pedal (310).

[0062] According to the control system (100) of an electric bicycle according to one embodiment of the present invention as described above, by controlling the pedal feel (pedal torque) in proportion to the rotational speed of the pedal independently of the motor torque (wheel torque) generation of the motor, an effect of easily generating a light pedal feel as needed can be achieved.

[0063] As described above, according to the embodiments of the present invention, unlike conventional electric bicycles that produce a pedal feel similar to a bicycle with a chain, an effect can be achieved in which the pedal feel can be flexibly adjusted based on the rotational speed of the pedal.

[0064] In addition, according to an embodiment of the present invention, since it is possible to control the pedal feel in proportion to the rotational speed of the pedal independently of the motor torque, the electric bicycle can be driven with a light pedal feel even when riding uphill on an inclined road or carrying a heavy load, thereby significantly reducing the driver's fatigue.

[0065] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0066] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0067] 100: Electric bicycle control system 111: Motor position sensor 112: Motor speed sensor 113: Motor current sensor 114: Generator position sensor 115: Generator speed sensor 116: Generator current sensor 120: Controller 121: Wheel speed control unit 122: Wheel Torque Control Unit 123: Pedal feel control unit 124: Pedal Torque Control Unit 130: Wheel Actuator (WA) 140: Pedal Actuator (PA) 200: Motor 210: Wheel 300: Generator 310: Pedal

Claims

Claim 1 A control method for an electric bicycle comprising: a step of detecting the rotational speed of a pedal and the speed of a wheel; a step of measuring the driving current of a motor driving the wheel and the driving current of a generator driven by the pedal; and a step of generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal, wherein in the step of generating the pedal torque command, the pedal feel is adjusted based on the rotational speed of the pedal regardless of the speed of the wheel. Claim 2 A control method for an electric bicycle according to claim 1, wherein the step of generating the pedal torque command is characterized by generating the pedal torque command such that a pedal torque proportional to the rotational speed of the pedal is generated. Claim 3 A method for controlling an electric bicycle according to claim 2, further comprising: a step of generating a pedal torque control current for controlling the pedal torque based on the generated pedal torque command and the measured driving current of the generator; and a step of controlling the current supplied to the generator based on the generated pedal torque control current. Claim 4 A method for controlling an electric bicycle, characterized in that, in any one of claims 1 to 3, it further comprises: a step of generating a wheel torque command based on the speed of the wheel and a wheel speed command obtained by multiplying the rotational speed of the pedal by a gear ratio; a step of generating a wheel torque control current for controlling the wheel torque based on the generated wheel torque command and the measured driving current of the motor; and a step of controlling the current supplied to the motor based on the generated wheel torque control current. Claim 5 A control system for an electric bicycle comprising at least one control unit, the control system comprising: at least one speed sensor unit for detecting the rotational speed of a pedal and the speed of a wheel; at least one current sensor unit for measuring the driving current of a motor driving a wheel and the driving current of a generator driven by a pedal; and a pedal feel control unit for generating a pedal torque command to adjust the pedal feel based on the rotational speed of the pedal, wherein the pedal feel control unit generates the pedal torque command to adjust the pedal feel based on the rotational speed of the pedal regardless of the speed of the wheel. Claim 6 A control system for an electric bicycle according to claim 5, wherein the pedal feel control unit generates a pedal torque command such that a pedal torque proportional to the rotational speed of the pedal is generated. Claim 7 A control system for an electric bicycle according to claim 6, further comprising a pedal torque control unit that generates a pedal torque control current for controlling the pedal torque based on the generated pedal torque command and the measured driving current of the generator. Claim 8 A control system for an electric bicycle according to claim 7, further comprising a pedal actuator for driving a generator, and controlling the pedal torque by supplying the generated pedal torque control current to the pedal actuator to control the current flowing through the generator. Claim 9 A control system for an electric bicycle, characterized in that, in any one of claims 5 to 8, it further comprises: a wheel speed control unit that generates a wheel torque command based on the speed of the wheel and a wheel speed command obtained by multiplying the rotational speed of the pedal by a gear ratio; and a wheel torque control unit that generates a wheel torque control current for controlling the wheel torque based on the generated wheel torque command and the measured driving current of the motor. Claim 10 A control system for an electric bicycle according to claim 9, further comprising a wheel actuator for driving a motor, and controlling the wheel torque by supplying the generated wheel torque control current to the wheel actuator to control the current flowing through the motor.

Images