Power-assisted system and vehicle with built-in automatic transmission mid-motor

Abstract

The application provides a power-assisted system with an automatic variable-speed middle motor and a vehicle. Under the action of a controller, the power-assisted system includes the following power-assisted modes: the first motor and the second motor are powered off, a driving force is transmitted to a middle shaft output gear disc through a crank of a pedal mechanism, and then the driving force is transmitted to a wheel output gear disc; or, the first motor and the second motor are powered on, action information is transmitted to the first motor through the crank of the pedal mechanism, the first motor senses a human power input state and feeds back to the controller, the controller sends a control instruction to the second motor according to a preset power-assisted curve, an output of the second motor is input to a driving output gear disc, and then the output is transmitted to a wheel output to drive. The power-assisted system realizes the switching between a human power mode and a hybrid mode by powering on or powering off the first motor and the second motor, and in the hybrid mode, the first motor functions as a replacement sensor, the second motor functions as a main driver, and the power-assisted curve is designed to improve the smoothness of power-assisted transition and the comfort of riding.

Description

Technical Field

[0001] This invention belongs to the field of internal speed change motor technology, specifically, it relates to a power assist system and vehicle with a built-in automatic transmission mid-drive motor. Background Technology

[0002] The internal geared dual-motor system is a power structure in the field of electric-assist bicycles. In existing electric-assist bicycle technology, in order to achieve power assist control, it usually relies on torque sensors and cadence sensors installed at the bottom bracket or crank of the vehicle to detect the rider's pedaling intention and force in real time, and then the controller provides corresponding electric assistance based on the signals from these sensors.

[0003] A Chinese patent application with publication number CN120397133A discloses a power system for an electric-assisted bicycle and an electric-assisted bicycle. The power system for the electric-assisted bicycle includes a housing, a bottom bracket, an electric assist device, and an electric speed control device. The bottom bracket is rotatably mounted on the housing. The electric assist device includes an assist motor and an assist transmission mechanism. The electric speed control device includes a speed control motor and a speed control transmission mechanism. By using the assist transmission mechanism in conjunction with the assist motor, a speed reduction and torque increase effect can be achieved, providing assistance to the rider, reducing the difficulty of riding, and alleviating the rider's fatigue.

[0004] Existing dual-motor power assist systems offer only one assist mode, making it difficult to meet user needs. This application proposes a power assist system with multiple assist modes. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide a power assist system and vehicle with a built-in automatic transmission mid-drive motor.

[0006] The power assist system with a built-in automatic transmission mid-drive motor provided by the present invention includes a first motor, a second motor, a first transmission system, a second transmission system, an external input mechanism, and a controller; The output shaft of the first motor is connected to the first transmission system, and the output shaft of the second motor is connected to the second transmission system. The second transmission system is connected to the first transmission system via a second transmission assembly, and the input shaft of the external input mechanism is connected to the second transmission system via the first transmission assembly. The second transmission system is connected to the first output unit, and the input shaft of the external input mechanism is connected to the second output unit via a clutch. Both the first output unit and the second output unit are connected to the wheel output unit in a transmission connection. Under the control of the controller, the following assistance modes are included: When the first motor and the second motor are de-energized, the input torque of the external input mechanism is transmitted to the wheel output unit through the second output unit; Alternatively, the first motor and the second motor are energized, and the driving torque of the external input mechanism is transmitted to the wheel output unit through the second output unit; at the same time, the first transmission component, the second transmission system, the second transmission component and the first transmission system transmit the action information to the first motor, the first motor senses the input state and feeds it back to the controller, the controller sends control commands to the second motor according to the preset execution program, and the output of the second motor is transmitted to the wheel output unit through the second transmission system and the first output unit.

[0007] In a preferred embodiment, the preset execution program includes a piecewise function, and the shape of the piecewise function is determined by at least three torque points; The specific form of the piecewise function is as follows:

[0008] in, Torque representing external input , This represents the calculated target assist torque of the second motor; It is a preset torque conversion point; when the pedaling torque is less than When the pedaling torque is equal to or greater than the pedaling torque, the assist torque is linearly related to the pedaling torque; when the pedaling torque is greater than or equal to the assist torque, the assist torque is linearly related to the pedaling torque. When this happens, a quadratic term is added to the function.

[0009] In a preferred embodiment, the shape of the preset execution program assist curve is determined by configuring at least three special torque points with clear physical meaning; These three points are: Minimum output point (x1, T1): The minimum basic assistance provided by the motor; Comfort pedaling point (x2, T2): The range of comfortable pedaling assistance provided by the motor; Hardest pedaling point (x3, T3): Powerful assistance provided by the motor; The controller automatically calculates all the unknown coefficients k1, b, k2 in the piecewise function by solving the system of three equations; the solution formula is as follows: .

[0010] In a preferred embodiment, under the action of the controller, an adaptive assist mode is also included: When the first motor and the second motor are powered on, the controller controls the drive input of the second motor and adjusts the speed input of the first motor in conjunction with it, so that the system can transmit the output drive at a preset transmission ratio. The vehicle's output driving torque is entirely provided by the second motor, while the first motor regulates the input power to support the torque reaction force of the second motor in the power assist system.

[0011] In a preferred embodiment, the first transmission assembly includes a first transmission member connected to the input shaft of an external input mechanism, a second transmission member connected to a second transmission system, and a third transmission member; The third transmission component is connected to the first and second transmission components in a transmission manner.

[0012] In a preferred embodiment, the clutch is a one-way clutch.

[0013] In a preferred embodiment, the second transmission assembly includes a fourth transmission member disposed in the second transmission system, a fifth transmission member connected to the first transmission system, and a sixth transmission member; The sixth transmission element is connected to the fourth and fifth transmission elements respectively.

[0014] In a preferred embodiment, the main body of the first transmission system and the main body of the second transmission system are offset from each other along the direction of the foot pedal shaft of the foot pedal mechanism.

[0015] In a preferred embodiment, the system further includes a power supply that powers the controller, the first motor, and the second motor.

[0016] According to the present invention, a power assist system with a built-in automatic transmission mid-mounted motor provides assistance to the vehicle.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves switching between manual mode and hybrid mode by energizing or de-energizing the first motor and the second motor. In hybrid mode, the first motor replaces the sensor and the second motor serves as the main drive. Furthermore, the design of the assist curve improves the smoothness of the assist transition and the comfort of riding. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This invention mainly embodies the principle diagram of the manual mode of the internal speed-changing dual-motor system; Figure 2 This is a schematic diagram illustrating the principle of the hybrid assist mode of the internal variable speed dual-motor system, which is the main feature of this invention. Figure 3 This invention mainly embodies the principle diagram of the pure power assist mode of the internal speed-changing dual-motor system; Figure 4This invention primarily illustrates the assist curve diagram; Figure 5 This invention mainly embodies the jitter suppression control block diagram; Figure 6 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 7 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 8 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 9 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 10 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 11 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 12 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 13 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 14 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 15 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 16 The present invention mainly embodies a feasible transmission system in Embodiment 4; Figure 17 This invention primarily embodies a feasible transmission system in Embodiment 4; Figure 18 The present invention mainly embodies a feasible transmission system in Embodiment 4.

[0019] exist Figures 1 to 3 middle, Figures 6 to 18 middle: R1 represents the ring gear of the first planetary gear set, C1 represents the planet carrier of the first planetary gear set, and S1 represents the sun gear of the first planetary gear set. R2 represents the ring gear of the second planetary gear set, C2 represents the planet carrier of the second planetary gear set, and S2 represents the sun gear of the second planetary gear set.

[0020] Figure label: Detailed Implementation

[0021] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0022] Example 1 like Figures 1 to 5 As shown, a power assist system with a built-in automatic transmission mid-drive motor according to the present invention includes a first motor M1, a second motor M2, a first transmission system, a second transmission system, an external input mechanism, and a controller. The system also includes a power supply that powers the controller, the first motor M1, and the second motor M2. The external input mechanism can be a foot pedal mechanism P, and the input shaft of the external input mechanism can be the foot pedal shaft of the foot pedal mechanism P.

[0023] The output shaft of the first motor M1 is connected to the first transmission system, and the output shaft of the second motor M2 is connected to the second transmission system. The second transmission system is connected to the first transmission system via the second transmission assembly Kf2, and the input shaft of the external input mechanism is connected to the second transmission system via the first transmission assembly Kf1. The second transmission system is connected to the first output unit OUT1, and the input shaft of the external input mechanism is connected to the second output unit OUT2 via the clutch CL. Both the first output unit OUT1 and the second output unit OUT2 are connected to the wheel output unit OUT3. Further, in this embodiment, the first transmission system can be a first planetary gear set PG1, and the second transmission system can be a second planetary gear set PG2. The first transmission component Kf1 can be a first gear transmission component, and the second transmission component Kf2 can be a second gear transmission component. The output shaft of the first motor M1 is drivenly connected to the sun gear S of the first planetary gear set, and the output shaft of the second motor M2 is drivenly connected to the sun gear S of the second planetary gear set. The ring gear R of the second planetary gear set is drivenly connected to the planet carrier C of the first planetary gear set through the second transmission component Kf2. The transmission ratio of the second transmission component Kf2 is a fixed transmission ratio. The pedal shaft of the foot pedal mechanism P is drivenly connected to the ring gear R of the second planetary gear set through the first transmission component Kf1. The transmission ratio of the first transmission component Kf1 is a fixed transmission ratio. A first output unit OUT1 is fixedly connected to the planet carrier C of the second planetary gear set. The first output unit OUT1 can be a drive output sprocket. A second output unit OUT2 is connected to the pedal shaft of the foot pedal mechanism P through a clutch CL. The second output unit OUT2 can be a bottom-axis output sprocket. Both the first output unit OUT1 and the second output unit OUT2 are connected to the wheel output unit OUT3, which can be a wheel output chain.

[0024] In one feasible implementation, the first output unit OUT1 is connected to the second output unit OUT2 via a first fixed transmission ratio Kf3, the first output unit OUT1 is connected to the wheel output unit OUT3 via a second fixed transmission ratio Kf4, and the second output unit OUT2 is connected to the wheel output unit OUT3 via a third fixed transmission ratio Kf5. The first fixed transmission ratio Kf3, the second fixed transmission ratio Kf4, and the third fixed transmission ratio Kf5 can all be achieved via belts or chains.

[0025] In one feasible implementation, the drive output chainring and the bottom bracket output chainring are connected to the wheel output chainring via a transmission assembly, which can be a chain or a belt.

[0026] Under the control of the controller, the following assistance modes are included: When the first motor M1 and the second motor M2 are de-energized, the input torque of the external input mechanism is transmitted to the wheel output unit OUT3 through the second output unit OUT2.

[0027] When the first motor M1 and the second motor M2 are powered on, the driving torque of the external input mechanism is transmitted to the wheel output unit OUT3 through the second output unit OUT2. At the same time, the first transmission component Kf1, the second transmission system, the second transmission component Kf2, and the first transmission system transmit the action information to the first motor M1. The first motor M1 senses the input state and feeds it back to the controller. The controller sends control commands to the second motor M2 according to the preset execution program. The output of the second motor M2 is transmitted to the wheel output unit OUT3 through the second transmission system and the first output unit OUT1.

[0028] In one feasible implementation, the first motor M1 and the second motor M2 are de-energized, and the input torque of the external input mechanism is transmitted to the wheel output unit OUT3 through the second output unit OUT2. That is, by pressing the crank of the pedal mechanism P, the driving force is transmitted to the bottom bracket output chain via the clutch CL, and then to the wheel output chain via the chain or belt.

[0029] Alternatively, the first motor M1 and the second motor M2 are energized, and the driving torque of the external input mechanism is transmitted to the wheel output unit OUT3 through the second output unit OUT2. That is, by pressing the crank of the pedal mechanism P, the driving torque is transmitted to the bottom bracket output chain via the clutch CL, and then to the wheel output chain via a chain or belt. At the same time, the first gear transmission assembly, the second planetary gear set PG2, the second gear transmission assembly, and the first planetary gear set PG1 transmit the action information to the first motor M1. The first motor M1 senses the input state and feeds it back to the controller. The controller sends control commands to the second motor M2 according to the preset execution program. The output of the second motor M2 is input to the drive output chain via the second planetary gear set PG2, and then transmitted to the output wheel via a chain or belt.

[0030] Under the control of the controller, an adaptive assist mode is also included: When the first motor M1 and the second motor M2 are energized, the controller controls the drive input of the second motor M2, and adjusts the speed input of the first motor M1 accordingly. The power assist system transmits the output drive at a preset transmission ratio. The vehicle's output drive force is entirely provided by the second motor M2, while the first motor M1 adjusts its input power to support the torque reaction force of the second motor M2 in the power assist system.

[0031] In this application's technical solution, the first motor M1 is mainly used as a speed-regulating motor, and the second motor M2 is mainly used as an assist motor. The first shaft system is formed by the first motor M1, the foot pedal mechanism P, and the first planetary gear set PG1, while the second shaft system is formed by the second motor M2 and the second planetary gear set PG2. The first and second shaft systems are parallel to each other. Compared to the dual-motor layout structure in the prior art, the two-shaft structure of this application's technical solution is more compact in terms of spatial structure.

[0032] In one feasible implementation, the first planetary gear set PG1 includes a sun gear S, a planet carrier C, and a ring gear R. Multiple planet gears are rotatably mounted on the planet carrier C, each planet gear meshing with the sun gear S, and each planet gear internally meshing with the ring gear R. The output shaft of the first motor M1 passes through the planet carrier and is fixedly connected to the sun gear S.

[0033] The second planetary gear set PG2 includes a sun gear S, a planet carrier C, and a ring gear R. Multiple planet gears are rotatably mounted on the planet carrier C, each of which meshes with the sun gear S, and each planet gear also meshes internally with the ring gear R. The output shaft of the second motor M2 passes through the planet carrier and is fixedly connected to the sun gear S.

[0034] It should be noted that, in a preferred embodiment, the planetary carrier C includes a mounting plate for mounting the planetary gears and a shaft section coaxially disposed in the middle of the mounting plate. In the first planetary gear set PG1, the outer surface of the ring gear R is fixedly connected to the housing, the planetary carrier C is mounted on the side of the ring gear R near the first motor M1, and the shaft section of the planetary carrier C extends in the direction close to the first motor M1. In the second planetary gear set PG2, the ring gear R is movably disposed relative to the housing, the planetary carrier C is mounted on the side of the ring gear R away from the second motor M2, and the shaft section of the planetary carrier C extends in the direction away from the second motor M2.

[0035] The first transmission assembly Kf1 includes a first transmission member connected to the input shaft of an external input mechanism, a second transmission member connected to a second transmission system, and a third transmission member. The third transmission member is connected to both the first and second transmission members. The first transmission member can be a transmission gear, the second transmission member can be a transmission gear, and the third transmission member can be an intermediate transmission gear. The first gear transmission assembly includes a transmission gear coaxially connected to the pedal shaft of the pedal mechanism P, a transmission gear coaxially connected to the ring gear R of the second planetary gear set PG2, and an intermediate transmission gear. The intermediate transmission gear meshes with two transmission gears. In a preferred embodiment, the clutch CL is a one-way clutch CL.

[0036] In a preferred embodiment, a transmission gear coaxially connected to the ring gear R of the second planetary gear set PG2 is rotatably connected to the shaft segment of the planet carrier C of the second planetary gear set PG2 via a bearing. The transmission gear includes a gear portion and a mating portion. The gear portion meshes with the intermediate transmission gear, and the mating portion is coaxially and fixedly connected to the outer end face of the ring gear R of the second planetary gear set PG2. The connection method of the mating portion and the outer end face of the ring gear R of the second planetary gear set PG2 being coaxially and fixedly connected can be achieved by a press fit of a recessed and raised structure arranged around the axial direction. The mounting bracket of the aforementioned intermediate transmission gear is fixedly connected to the motor housing, and the mounting bracket is rotatably engaged with the shaft segment of the planet carrier C of the second planetary gear set PG2. Specifically, the mounting bracket of the intermediate transmission gear is coaxially sleeved and installed between the gear portion and the mating portion of the transmission gear, and is rotatably connected via a bearing.

[0037] The second transmission assembly Kf2 includes a fourth transmission element disposed in the second transmission system, a fifth transmission element connected to the first transmission system, and a sixth transmission element; the sixth transmission element is drivingly connected to the fourth and fifth transmission elements respectively. The fourth transmission element may be a toothed portion disposed on the outer surface of the ring gear R of the second planetary gear set PG2, the fifth transmission element may be a transmission gear, and the sixth transmission element may be an intermediate transmission gear. The second gear transmission assembly includes a toothed portion disposed on the outer surface of the ring gear R of the second planetary gear set PG2, a transmission gear coaxially fixedly connected to the shaft of the planet carrier C of the first planetary gear set PG1, and an intermediate transmission gear. The intermediate transmission gear meshes with the toothed portion on the outer surface of the ring gear R of the second planetary gear set PG2 and the transmission gear respectively. The mounting bracket of the intermediate transmission gear is coaxially sleeved on the shaft section of the planet carrier C of the first planetary gear set PG1, and the mounting bracket is rotatably engaged with the shaft section of the planet carrier C of the first planetary gear set PG1.

[0038] In a preferred embodiment, the main body of the first transmission system and the main body of the second transmission system are offset from each other along the direction of the foot pedal shaft P. That is, the ring gear R of the first planetary gear set PG1 and the ring gear R of the second planetary gear set PG2 are offset from each other along the direction of the foot pedal shaft P.

[0039] It should be noted that the first motor M1 and the second motor M2 in the technical solution of this application can be controlled by a controller, and the first motor M1, the second motor M2 and the controller are powered by a power supply.

[0040] The following working modes can be further realized using the structure of the technical solution of this application: like Figure 1 The manual mode shown relies solely on external input for driving force when the first motor M1 and the second motor M2 are powered down. In this mode, the first motor M1 acts as a generator, the second motor M2 rotates slightly, the central shaft output sprocket outputs power, and the output sprocket rotates accordingly. The manual power output is as follows: Figure 1 As shown by the red line, the external input is transmitted to the bottom bracket output sprocket for main output via the foot pedal mechanism P and clutch CL. The driven power flow is shown by the blue line; the bottom bracket output sprocket drives the drive output sprocket to rotate, which in turn drives the planet carrier C of the second planetary gear set PG2, and consequently, slightly rotates the second motor M2. The power flow of the first motor M1 is shown by the green line; the external input is transmitted to the ring gear R of the second planetary gear set PG2 via the foot pedal mechanism P and the first transmission component Kf1, then to the planet carrier C of the first planetary gear set PG1, and finally to the first motor M1 for power generation.

[0041] like Figure 2The hybrid assist mode shown, with both the first motor M1 and the second motor M2 powered, uses the first motor M1 to sense external input states, such as pedal cadence and pedaling torque, while the second motor M2 provides the main output. In this mode, the first motor M1 acts as a torque sensor and transmission power source, while the second motor M2 acts as an assist motor, with the bottom bracket outputting the crankset output and driving the crankset for assist output. The power flow is as follows: Figure 2 As shown by the cyan line, external input is transmitted to the bottom bracket output chainring via the foot pedal mechanism P and clutch CL, providing manual output and driving the output chainring to rotate at the same speed. The power assist flow is as follows... Figure 2 As shown by the red line, the rotation of the second motor M2 drives the second planetary gear set PG2, which in turn drives the output chainring for power assist. The power generated by the first motor M1 flows as follows: Figure 2 As shown by the blue lines, the external input is transmitted through the foot pedal mechanism P and the first transmission component Kf1 to the ring gear R of the second planetary gear set PG2, then to the planet carrier C of the first planetary gear set PG1, and finally to the first motor M1, which acts as a torque sensor. The power flow of the transmission is as follows: Figure 2 As shown by the green line, the rotation of the first motor M1 drives the first planetary gear set PG1, which in turn drives the gear ring R of the second planetary gear set PG2 to rotate, thus achieving speed change.

[0042] like Figure 3 The adaptive assist mode shown, with both the first motor M1 and the second motor M2 powered on, requires no external power input. The controller memorizes the adaptive riding state or a preset riding state from the previous hybrid mode state after external input, and adaptively controls the output of the second motor M2, i.e., the adaptive assist mode. In this mode, the first motor M1 acts as the power source for gear shifting, and the second motor M2 acts as the assist motor, driving the crankset for assist and gear shifting. The assist power flow is as follows... Figure 3 As shown by the red line, the second motor M2 rotates, driving the second planetary gear set PG2, which in turn drives the output chainring for power assist. The driven power flows as follows: Figure 3 As shown, the first motor M1 drives the second planetary gear set PG2 through the second transmission component Kf2, and then drives the foot pedal mechanism P to rotate through the first transmission component Kf1. The power flow of the speed change is as follows: Figure 3 As shown by the green line, the first motor M1 drives the gear ring R of the second planetary gear set PG2 to rotate through the second transmission component Kf2, thereby achieving speed change.

[0043] The overall system, with its coaxial design, incorporates a first motor M1 as the power source for gear shifting and the main sensor mechanism, and a second motor M2 as the main assist motor mechanism, forming a centrally located internal gear shifting system. This better addresses the issue of excessive unsprung mass in the wheel hub, overcomes more complex operating conditions, and improves vehicle operational reliability. Unlike conventional dual-motor solutions, the first motor M1, serving as the power source for gear shifting and the main sensor mechanism, is designed for good low-speed stability and smooth rotation, making it more suitable for the detection and adjustment of the manually driven shaft. It also allows for enhanced heat dissipation within the space of the first motor M1, supporting the drive motor's long-term high-torque output and thus improving its output capacity. The second motor M2, as the main assist motor mechanism, is designed for fast acceleration and deceleration response, better integrating with rotor position and angle control methods and a multi-stage planetary gear structure. This allows for better control of output in response to complex riding feedback conditions, improving motor energy efficiency and riding comfort. Simultaneously, it optimizes the internal mass distribution of the motor, enhancing its overall dynamic response and reducing overall vibration and noise.

[0044] In this embodiment, the controller may be a microcontroller unit that integrates a processor and a memory. The memory contains computer program instructions that implement this method, and the processor is responsible for executing these instructions.

[0045] Specifically, the controller continuously acquires the real-time speed signal of the first motor M1 at a preset frequency (e.g., every 10 milliseconds) through a built-in sensor or driver feedback interface. and current signal and the real-time speed signal of the second motor M2. and current signal It should be noted that the current signal mainly refers to the q-axis current component that directly reflects the motor's output torque, i.e. and It is understood that the motor's own operating signal constitutes the sole signal input source for this control method, thus eliminating the need to install any external torque or cadence sensors on the bottom bracket, crank, or rear axle.

[0046] Fitting cadence and torque. This step is crucial for achieving sensorless control, involving precise estimation of two core parameters: rider cadence and pedaling torque. Since the first motor M1 is connected to the ring gear R of the second planetary gear set PG2 via the first planetary gear set PG1 and the fixed-ratio second transmission component Kf2, and the pedal mechanism P is also connected to the same ring gear R via the fixed-ratio first transmission component Kf1, it can be known that there is a constant proportional relationship between the rotational speed of the first motor M1 and the rider's cadence. The controller uses this relationship to calculate the cadence. Specifically, the controller can first calculate the cadence based on the rotational speed of the first motor M1... and the known speed ratio (This represents the transmission ratio from the first motor M1 to the second planetary gear set PG2, specifically the gear ring R.) Calculate the rotational speed of the gear ring R. .

[0047] Specifically, the fitting estimation of the externally input cadence signal includes: Based on the speed of the first motor and the known speed ratio Calculate the rotational speed of the ring gear R of the second planetary gear set PG2 connected to the second motor M2. The calculation formula is as follows:

[0048] : Indicates the transmission ratio from the first motor M1 to the ring gear R of the second planetary gear set PG2 connected to the second motor M2; Based on the rotational speed of the ring gear R of the second planetary gear set PG2 connected to the second motor M2 and the known speed ratio Calculate the real-time cadence of the external input. The calculation formula is as follows:

[0049] : Indicates the transmission ratio from the external input shaft to the gear ring R of the second planetary gear set PG2 connected to the second motor M2.

[0050] Through this calculation method, the controller can obtain the frequency of the external input, i.e., the rider's pedaling frequency, in real time and accurately, thereby realizing the functional replacement of the physical pedal frequency sensor. This process reflects the technical idea of ​​this application to estimate the pedal frequency signal based on the proportional relationship between the rotational speed of the first motor M1 and the externally input rider's pedal frequency.

[0051] Next, the pedaling torque is fitted and estimated. This estimation is based on the torque balance principle at the ring gear R of the second planetary gear set PG2. During dynamic riding, the torques acting on the ring gear R of the second planetary gear set PG2 are balanced. These torques include: the driving torque transmitted by the second motor M2, the supporting or driving torque applied by the first motor M1, and the pedaling torque applied by the rider through the pedal mechanism P.

[0052] To determine the cyclist's pedaling torque, other relevant variables in the system must first be identified. One of these is the real-time reduction ratio of the transmission system. This value is not fixed, but changes dynamically with the rotational speed of the first motor M1 and the second motor M2.

[0053] Specifically, the fitting estimation of the external input torque includes: Determine the real-time reduction ratio Real-time reduction ratio It is calculated using the following formula:

[0054] in, The inherent speed ratio of the second planetary gear set PG2, which is connected to the second motor M2; It is the real-time rotational speed of the second motor; It is the rotational speed of the ring gear R of the second planetary gear set PG2, which is connected to the second motor M2; Establishing the torque balance equation, at the gear ring R of the second planetary gear set PG2 connected to the second motor M2, the torque balance relationship is expressed as:

[0055] in, , and These represent the equivalent torques of the second motor M2, the first motor M1, and the external input on the ring gear R of the second planetary gear set PG2 connected to the second motor M2, respectively. in, ; ; in, and It is the actual output torque of the two motors. It is the externally input torque; the motor's output torque is determined by its q-axis current and torque constant. Calculated, i.e. ; By combining the above relationships and substituting them into the torque balance equation, the externally input torque can be solved. : .

[0056] In this way, the controller can accurately calculate the pedaling torque applied by the cyclist using only the current and speed signals of the two motors, thus replacing the function of a high-precision physical torque sensor. This process embodies the technical approach of this application: estimating pedaling torque based on torque balance relationships.

[0057] To achieve the aforementioned torque balance and accurate estimation, this embodiment employs differentiated collaborative control strategies for the two motors. Specifically, a speed loop control strategy is used for the first motor M1. Its main functions are, on the one hand, to act as a dynamic "sensor" to track the rider's cadence, and on the other hand, to act as a "supporter" to maintain torque balance, creating conditions for M2 to output driving torque. Its current command will adaptively change with the rider's pedaling torque. Correspondingly, a current loop control (i.e., torque loop control) is used for the second motor M2. Among them, M2, as the active power source, has its current command directly determined by the subsequent assist algorithm, responsible for providing the main, responsive driving force for the entire vehicle.

[0058] After acquiring real-time cadence and pedaling torque, the riding intention can be determined. Based on the estimated externally input cadence and torque signals, the user's intention is determined by comparing them with preset thresholds. The user's intention includes starting and stopping intentions. When the externally input cadence signal is greater than the starting cadence threshold and the externally input torque is greater than the starting torque threshold, it is determined to be a starting intention; when the externally input cadence signal is less than the stopping cadence threshold, it is determined to be a stopping intention. When a starting or stopping intention is determined, the current command to the second motor is changed in a ramp manner to achieve smooth control. Specifically, the controller compares the estimated parameters with preset thresholds in memory. For example, when the controller detects that the cadence is greater than the preset starting cadence threshold (e.g., 20 RPM) and the pedaling torque is greater than the preset starting torque threshold (e.g., 2 Nm), it determines that the cyclist has a starting intention and executes the starting control steps. When the controller detects that the cadence is lower than the preset stop cadence threshold (e.g., 10 RPM) or the pedaling torque is lower than the preset stop torque threshold (e.g., 0.5 Nm), it determines that the rider intends to stop and executes the stop control steps. If neither the start nor stop conditions are met, it is considered to be in normal assist state, and the process enters the assist calculation and output steps.

[0059] The steps for calculating and outputting assist are as follows: The controller calculates and outputs the assist based on the currently estimated pedaling torque. The controller, taking into account the vehicle's current status (such as speed and power steering gear), determines the target power steering torque that the second motor M2 should output by referring to or calculating a preset power steering curve and executing a preset program. Subsequently, the controller converts this target power steering torque into a corresponding q-axis current command based on the motor torque constant. .

[0060] Ultimately, the controller will calculate the resulting current command. The driver for the second motor M2 sends a command to the driver for the first motor M1, while simultaneously sending a speed command for tracking cadence. The driver then controls the motor's operation accordingly to provide intelligent assistance to the rider. This entire process is executed cyclically, forming a continuously operating closed-loop control system, thus ensuring the real-time performance and accuracy of the assistance.

[0061] Figure 4 The shape and principle of the assist curve are visually illustrated. Essentially, the assist curve is a function that defines the mapping relationship between the rider's pedaling torque (X-axis), the input variable, and the motor's assist torque (Y-axis), the output variable. By changing the shape of this curve, the motor's assist characteristics can be significantly altered, thus creating different riding experiences.

[0062] In this embodiment, the assist curve is not fixed but dynamically generated by a piecewise function containing both linear and nonlinear components. This design aims to balance smoothness in the low pedaling torque range with responsiveness in the high pedaling torque range. The specific form of this piecewise function is as follows:

[0063] in, Torque representing external input , This represents the calculated target assist torque of the second motor; It is a preset torque conversion point; when the pedaling torque is less than When the pedaling torque is equal to or greater than the pedaling torque, the assist torque is linearly related to the pedaling torque, providing stable and predictable assistance; when the pedaling torque is greater than or equal to the pedaling torque, the assist torque is linearly related to the pedaling torque. At this point, a quadratic term is added to the function. This allows the pedal assist to increase more quickly with increasing pedaling force, providing a stronger sense of power.

[0064] A technical feature of this embodiment is that the shape of the assist curve executed by the preset program is not defined by a complex parameter table, but is uniquely determined by configuring at least three special torque points with clear physical meaning. These three points are: 1. Minimum output point (x1, T1): Defines the minimum basic assistance (torque of T1) provided by the motor when the rider pedals lightly (torque of x1).

[0065] 2. Comfortable pedaling point (x2, T2): Defines the amount of assistance (torque T2) provided by the motor in the comfortable pedaling range under normal and comfortable pedaling force (torque x2).

[0066] 3. Point of maximum effort (x3, T3): Defines the strong assistance (torque T3) provided by the motor when the rider pedals very hard (torque x3).

[0067] Once these three points are set, the controller can automatically calculate all the unknown coefficients k1, b, k2 in the piecewise function by solving the system of three equations. The solution formula is as follows:

[0068] The conversion point Z can typically be x2, or set to other values ​​as needed.

[0069] This design offers exceptional flexibility. The controller can be preset with multiple different torque point configurations, each corresponding to a riding mode. Users can select different modes via physical buttons on the vehicle, the dashboard menu, or a connected mobile application. When a user switches modes, the controller immediately loads the corresponding torque point configuration and recalculates the coefficients k1, b, and k2 to generate a completely new assist curve.

[0070] For example, the system can preset the following three modes: Eco Mode: This mode aims to maximize range. Its configuration points can be set as follows: minimum power output point (x1,T1)=(3Nm,1Nm), comfortable pedaling point (x2,T2)=(10Nm,4Nm), and strenuous pedaling point (x3,T3)=(30Nm,12Nm). The calculated assist curve is relatively flat overall, and the assist ratio provided is correspondingly lower. Normal Mode: This mode provides a balanced performance and range. Its configuration points can be set as follows: (x1,T1)=(3Nm,2.5Nm), (x2,T2)=(10Nm,10Nm), (x3,T3)=(30Nm,30Nm). In this mode, within the comfortable riding range, the assist ratio can approach 1:1. Sport Mode: This mode aims to provide the strongest power response. Its configuration points can be set as follows: (x1,T1)=(3Nm,4Nm), (x2,T2)=(10Nm,18Nm), (x3,T3)=(30Nm,50Nm). The resulting assist curve is very steep, and even a small pedaling torque can provide a large amount of motor assistance.

[0071] In a real-world cycling scenario, assuming a cyclist is riding in normal mode on a flat road, applying 10 Nm of pedaling force, the motor outputs 10 Nm of assistance. When encountering a steep incline, the cyclist switches to sport mode via a button on the handlebars. The controller immediately adopts the sport mode's assistance curve. Now, the cyclist applies the same 10 Nm of pedaling force, but according to the new curve, the motor's assistance torque jumps to 18 Nm, helping the cyclist easily overcome the incline. The entire switching process is instantaneous, providing users with an excellent interactive experience and practicality.

[0072] This embodiment also provides a vehicle employing the aforementioned power steering system with a built-in automatic transmission mid-drive motor. The power steering system with a built-in automatic transmission mid-drive motor provides assistance to the vehicle.

[0073] Example 2 Based on Embodiment 1, in another embodiment, this application also provides an active vibration suppression control strategy for improving riding smoothness. This strategy mainly addresses the high-frequency vibration and impact problems in the transmission system caused by factors such as uneven road surfaces, chain jumps, gear meshing clearance, or sudden load changes during riding, thereby providing a smooth and comfortable power output experience.

[0074] This control logic can serve as an additional compensation element for the current loop control of the second motor M2, and operates in a feedforward manner to actively counteract torque fluctuations that are about to occur or are currently occurring.

[0075] The core idea of ​​this jitter suppression algorithm is that high-frequency jitter in the transmission system will inevitably be reflected in the speed and current signals of the second motor M2. By performing specific processing on these signals, the components characterizing the jitter can be extracted, and a compensation signal can be generated accordingly.

[0076] The specific implementation process is as follows: 1. Signal Acquisition: During the main control cycle, the controller continuously monitors the real-time speed feedback signal and current feedback signal of the second motor M2.

[0077] 2. Fluctuation Component Extraction: The jitter suppression algorithm module inside the controller processes the acquired signal. On one hand, the speed feedback signal of the second motor M2 can be input to a digital high-pass filter. This filter removes DC and low-frequency components (representing normal acceleration and deceleration of the vehicle), retaining only high-frequency fluctuation components. When the wheel rolls over stones or encounters potholes, the wheel speed undergoes a sudden change. This change is transmitted to the speed of the second motor M2 through the transmission chain, forming high-frequency speed spikes or dips. This signal can be effectively captured by the high-pass filter. On the other hand, as an optional or supplementary solution, the current feedback signal (q-axis current) of the second motor M2 can also be processed through another high-pass filter, because current fluctuations directly reflect the torque fluctuations generated by the motor to resist load fluctuations.

[0078] 3. Compensation Signal Generation: One or more extracted high-frequency fluctuation signals (e.g., speed fluctuation signal and current fluctuation signal) are weighted and superimposed. The weights can be experimentally calibrated to achieve the best suppression effect. The superimposed signal represents the current total jitter state of the system. Subsequently, this jitter state signal is input to the compensation stage (e.g., low-pass filter or proportional-integral controller) to generate the final compensation current command. The function of the low-pass filter is to smooth and compensate the signal, avoiding the introduction of new high-frequency noise.

[0079] 4. Feedforward compensation: The generated compensation current command The base current command calculated by the main assist algorithm The commands are superimposed. That is, the total current command ultimately issued to the second motor M2 driver. for:

[0080] The following scenario illustrates its operation: Suppose an electric-assisted bicycle is being ridden smoothly when the wheel suddenly runs over an obstacle (such as a tree branch), causing a sudden increase in load on the rear wheel. This impact will cause a slight, instantaneous drop in the speed of the second motor M2, while its output current will momentarily and passively increase to maintain the speed. The high-pass filter in the jitter suppression algorithm module will immediately capture these two rapidly changing quantities and quickly generate a negative compensation current command. This negative compensation current will temporarily and actively reduce the total current command. Its function is equivalent to "absorbing" the impact at a physical level, making the torque change acting on the chain more gradual. When the impact subsides and the load returns to normal, the speed and current will fluctuate in opposite directions, and the algorithm will generate a positive compensation current to make the torque recover quickly and smoothly. The entire compensation process occurs in milliseconds, making the rider almost unaware of the impact from the road surface, only feeling a stable and gentle power output.

[0081] By implementing this active vibration suppression algorithm, various high-frequency vibrations and impacts during riding can be effectively filtered out. This not only significantly improves riding comfort but also reduces impact wear on transmission components such as planetary gear sets and chains, helping to extend the service life of the vehicle.

[0082] Example 3 Based on Embodiment 1 or Embodiment 2, this embodiment further elaborates on how to ensure a smooth transition of assist torque through a smooth control strategy when switching riding intentions, especially during the start and stop phases, in order to solve the common problems of abrupt start and "kickback" when stopping in traditional electric-assist bicycles. This embodiment can be regarded as a specific implementation of Embodiment 1.

[0083] First, regarding smooth start control: When the controller determines that the rider intends to start according to the judgment logic described in Embodiment 1, it will not cause the current command of the second motor M2 to jump instantaneously to the target value calculated by the assist curve. Applying a large assist torque instantaneously could easily cause the vehicle to lurch forward, bringing insecurity and discomfort to the rider.

[0084] To achieve a smooth start, this embodiment uses a ramp function to process the control command. Specifically, within a short period after determining the intention to start (for example, it can be set to 100 milliseconds to 300 milliseconds), the controller causes the current command of the second motor M2 to start from 0 and gradually increase in preset steps until it reaches the target current value calculated from the current pedaling torque and the assist curve. The iterative formula for its instruction update can be expressed as:

[0085] in, It is the current command value at the current moment. It is the instruction value from the previous moment. It is a fixed current increment step. This process continues until... equal to or greater than In this way, the assist torque can be applied smoothly, making the start-up process feel natural and linear to the rider.

[0086] As a preferred approach, while performing ramp control on the current command of the second motor M2, a similar smoothing process can also be applied to the target speed loop value of the first motor M1. For example, its target speed can be smoothly increased from zero at rest to a value that matches the cadence of the rider as they accelerate. This helps the entire dual-motor system work more harmoniously.

[0087] Secondly, regarding smooth shutdown control. The quality of shutdown control directly affects riding safety, and its key lies in eliminating the "kickback" phenomenon. "Kickback" refers to the situation where, after the rider stops pedaling, the motor continues to output positive thrust due to improper control logic, causing the pedals to impact the rider's feet in the opposite direction.

[0088] In this embodiment, when the controller determines an intention to stop (e.g., cadence below the stop threshold), it strictly follows the torque withdrawal sequence of "first canceling assist, then adjusting support." The first step is to immediately and smoothly cancel the assist torque of the second motor M2. Similar to starting, the controller uses a ramp function to send a current command to the second motor M2. The current value decreases rapidly and linearly to 0, a process typically set to be faster than the startup process, for example, completing within 100 milliseconds. The second step involves the controller monitoring the actual current feedback of the second motor M2. Once it confirms that the output torque has completely disappeared, it adjusts the control state of the first motor M1 accordingly. For example, it can switch the speed loop control mode to zero-torque control mode or directly enter standby mode to reduce system energy consumption.

[0089] The following scenario illustrates its operation: When a cyclist stops pedaling as they approach a traffic light, their cadence drops rapidly. The controller detects that the cadence is below the stopping threshold and immediately determines this as a stop intention. At this moment, the controller instantly activates a ramp function, reducing the current command of the second motor M2 by a preset step size, causing it to drop completely to zero within a very short time (e.g., 150 milliseconds). Since the primary power source, the second motor M2, no longer generates any thrust, and the first motor M1, which is linked to the pedals, is also in a following or zero-torque state, the pedal mechanism will naturally decelerate until it stops due to wheel inertia, thus avoiding any reverse impact on the cyclist's feet.

[0090] By implementing the above-mentioned smooth start-stop control strategy, the control method provided in this application can achieve a smooth start-stop experience, ensuring that the assist is gentle and shock-free when starting, and that the response is rapid and safe when stopping, thereby significantly improving the product's quality and the user's riding experience.

[0091] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0092] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0093] Example 4 Based on Embodiment 1, Embodiment 2, or Embodiment 3, the present invention provides a power assist system with a built-in automatic transmission mid-drive motor, comprising a first motor M1, a second motor M2, a first transmission system, a second transmission system, an external input mechanism, and a controller. The system also includes a power supply, which powers the controller, the first motor M1, and the second motor M2. The external input mechanism can be a foot pedal mechanism P, and the input shaft of the external input mechanism can be the foot pedal shaft of the foot pedal mechanism P. The output shaft of the first motor M1 is connected to the first transmission system, and the output shaft of the second motor M2 is connected to the second transmission system. The second transmission system is connected to the first transmission system via a second transmission component Kf2, and the input shaft of the external input mechanism is connected to the second transmission system via the first transmission component Kf1. The second transmission system is connected to a first output unit OUT1, and the input shaft of the external input mechanism is connected to a second output unit OUT2 via a clutch CL. Both the first output unit OUT1 and the second output unit OUT2 are connected to a wheel output unit. It should be emphasized in this embodiment that the transmission system, which consists of the first motor M1, the second motor M2, the first transmission system, the second transmission system, the first transmission component Kf1, the second transmission component Kf2, and the external input mechanism, can be implemented in various ways, all of which can be adapted to the assist mode of the technical solution of this application.

[0094] like Figure 6 As shown, the first transmission system uses a first planetary gear set PG1, and the second transmission system uses a second planetary gear set PG2. Both the first transmission component Kf1 and the second transmission component Kf2 use gears or gear sets. Preferably, idler gears or idler gear sets are used. The output shaft of the first motor M1 is connected to the sun gear S of the first planetary gear set PG1, and the output shaft of the second motor M2 is connected to the sun gear S of the second planetary gear set PG2. The ring gear R of the second planetary gear set PG2 is connected to the planet carrier C of the first planetary gear set PG1 through the second transmission component Kf2. The transmission ratio of the second transmission component Kf2 is a fixed transmission ratio. The pedal shaft of the foot pedal mechanism P is connected to the ring gear R of the second planetary gear set PG2 through the first transmission component Kf1. The transmission ratio of the first transmission component Kf1 is a fixed transmission ratio. The first output unit OUT1 is fixedly connected to the planet carrier C of the second planetary gear set PG2. The first output unit OUT1 can be a drive output sprocket. The second output unit OUT2 is connected to the foot shaft of the foot pedal mechanism P through the clutch CL. The second output unit OUT2 can be a bottom shaft output sprocket.

[0095] The first transmission assembly Kf1 includes a transmission gear coaxially connected to the pedal shaft of the pedal mechanism P, a transmission gear coaxially connected to the ring gear R of the second planetary gear set PG2, and an intermediate transmission gear. The intermediate transmission gear meshes with the two transmission gears respectively. A reversing structure can be provided in the first transmission assembly Kf1 to allow the intermediate transmission gear to mesh with or disengage from the two transmission gears. The second transmission assembly Kf2 includes teeth on the outer surface of the ring gear R of the second planetary gear set PG2, a transmission gear coaxially fixedly connected to the shaft of the planet carrier C of the first planetary gear set PG1, and an intermediate transmission gear. The intermediate transmission gear meshes with the teeth on the outer surface of the ring gear R of the second planetary gear set PG2 and the transmission gears respectively. Furthermore, the ring gear R of the first planetary gear set PG1 and the ring gear R of the second planetary gear set PG2 are offset along the pedal shaft of the pedal mechanism P. It should be noted that the reversing structure of the technical solution of this application adopts any existing structure or system that meets the space requirements of this application and can achieve gear meshing or contact meshing.

[0096] like Figure 7 As shown, in one variant implementation, in Figure 6 Based on the proposed solution, a reversing structure can be set in the second transmission component Kf2 to change the meshing direction of the teeth on the outer surface of the intermediate transmission gear and the outer surface of the second planetary gear set PG2 ring gear R, so that the directions of the power transmission path and the power output path are consistent.

[0097] like Figure 8 As shown, in one variant implementation, in Figure 6 Based on the proposed solution, the reversing structure in the first transmission assembly Kf1 is removed. In the first transmission assembly Kf1, the intermediate transmission gear meshes with the two transmission gears respectively.

[0098] like Figure 9 As shown, in one variant implementation, in Figure 6 Based on the proposed solution, the second output unit OUT2 is removed, and a transmission assembly is introduced. The transmission assembly includes a first gear connected to the pedal shaft of the pedal mechanism P via a clutch CL, and a second gear coaxially and fixedly connected to the planet carrier C of the second planetary gear set PG2. The first output unit OUT1 is fixedly connected to the second gear. An idler gear or idler gear set is provided between the first gear and the second gear for reversing, so that the directions of the power transmission path and the power output path are consistent.

[0099] like Figure 10 As shown, in one variant implementation, in Figure 7 Based on the proposed scheme, the spatial positions of the first planetary gear set PG1 and the second planetary gear set PG2 were adjusted, and the ring gear R of the first planetary gear set PG1 was changed from... Figure 7The scheme that was closer to the first motor M1 was changed to a scheme that was farther away from the first motor M1, and the transmission structure between the first planetary gear set PG1 and the second planetary gear set PG2 remained unchanged, further utilizing the axial space of the motor.

[0100] like Figure 11 As shown, in one variant implementation, in Figure 10 Based on the proposed solution, the reversing structures in the first transmission assembly Kf1 and the second transmission assembly Kf2 are removed, the second output unit OUT2 is removed, and a transmission assembly is introduced. The transmission assembly includes a first gear connected to the pedal shaft of the pedal mechanism P via a clutch CL, and a second gear coaxially and fixedly connected to the planet carrier C of the second planetary gear set PG2. The first output unit OUT1 is fixedly connected to the second gear, and the first gear meshes with the second gear.

[0101] like Figure 12 As shown, in one variant implementation, in Figure 7 Based on the scheme, the difference is that the foot pedal shaft of the foot pedal mechanism P does not pass through the first motor M1.

[0102] like Figure 13 As shown, in one variant implementation, in Figure 7 Based on the original design, the difference lies in the fact that the second planetary gear set PG2 has an increased speed ratio, resulting in more powerful output.

[0103] like Figure 14 As shown, in one variant implementation, in Figure 7 Based on the original scheme, the difference lies in the introduction of a transmission gear set, which includes an output gear coaxially connected to the output shaft of the second motor M2 and a transmission gear coaxially connected to the sun gear S of the second planetary gear set PG2. The output gear meshes with the transmission gear.

[0104] like Figure 15 As shown, in one variant implementation, in Figure 7 Based on the original scheme, the difference is that the first motor M1 and the second motor M2 are built in. The first motor M1 is set closer to the second output unit OUT2 than the gear ring R of the first planetary gear set PG1, and the second motor M2 is set closer to the first output unit OUT1 than the gear ring R of the second planetary gear set PG2. An idler gear set is added to the original second transmission component Kf2 to increase the output transmission ratio of the first motor M1.

[0105] like Figure 16 As shown, in one variant implementation, in Figure 15Based on the original scheme, the difference lies in removing the second output unit OUT2 and introducing a transmission assembly. This transmission assembly includes a first idler gear connected to the pedal shaft of the pedal mechanism P via a clutch CL, and a second idler gear coaxially and fixedly connected to the planet carrier C of the second planetary gear set PG2. The first output unit OUT1 is fixedly connected to the second idler gear, and the first and second idler gears mesh. Furthermore, the second motor M2 is positioned closer to the first output unit OUT1 than the ring gear R of the second planetary gear set PG2, and the first motor M1 is positioned closer to the first output unit OUT1 than the ring gear R of the first planetary gear set PG1.

[0106] like Figure 17 As shown, in one variant implementation, in Figure 6 Based on this scheme, the first transmission assembly Kf1 and the second transmission assembly Kf2, which are formed by gears or idler gear sets, are replaced with belt and pulley drives. It should be noted that this can be referenced... Figure 7 Plan to Figure 16 Plans and Figure 6 The differences between the two plans will be... Figure 7 Plan to Figure 16 The first transmission component Kf1 and the second transmission component Kf2, which are formed by gears or idler gear sets, are replaced by belts and pulleys in the scheme.

[0107] like Figure 18 As shown, in one variant implementation, in Figure 6 Based on the proposed solution, a clutch CL is installed between the pedal shaft of the foot pedal mechanism P and the planet carrier C of the first planetary gear set PG1, forming a dual-clutch CL structure with the clutch CL between the pedal shaft of the foot pedal mechanism P and the second output unit OUT2. It should be noted that... Figures 7 to 18 In the transmission scheme, any transmission system with a dual-clutch CL setting can refer to this. Figure 18 The proposed solution is to install a dual-clutch CL system.

[0108] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0109] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A power assist system with a built-in automatic transmission mid-mounted motor, characterized in that, It includes a first motor, a second motor, a first transmission system, a second transmission system, an external input mechanism, and a controller; The output shaft of the first motor is connected to the first transmission system, and the output shaft of the second motor is connected to the second transmission system. The second transmission system is connected to the first transmission system via a second transmission assembly, and the input shaft of the external input mechanism is connected to the second transmission system via the first transmission assembly. The second transmission system is connected to the first output unit, and the input shaft of the external input mechanism is connected to the second output unit via a clutch. Both the first output unit and the second output unit are connected to the wheel output unit in a transmission connection. Under the control of the controller, the following assistance modes are included: When the first motor and the second motor are de-energized, the input torque of the external input mechanism is transmitted to the wheel output unit through the second output unit; Alternatively, the first motor and the second motor are energized, and the driving torque of the external input mechanism is transmitted to the wheel output unit through the second output unit; at the same time, the first transmission component, the second transmission system, the second transmission component and the first transmission system transmit the action information to the first motor, the first motor senses the input state and feeds it back to the controller, the controller sends control commands to the second motor according to the preset execution program, and the output of the second motor is transmitted to the wheel output unit through the second transmission system and the first output unit.

2. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The preset execution program includes a piecewise function, and the shape of the piecewise function is determined by at least three torque points; The specific form of the piecewise function is as follows: in, Torque representing external input , This represents the calculated target assist torque of the second motor; It is a preset torque conversion point; when the pedaling torque is less than When the pedaling torque is equal to or greater than the pedaling torque, the assist torque is linearly related to the pedaling torque; when the pedaling torque is greater than or equal to the assist torque, the assist torque is linearly related to the pedaling torque. When this happens, a quadratic term is added to the function.

3. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 2, characterized in that, The shape of the preset execution program assist curve is determined by configuring at least three special torque points with clear physical meaning; These three points are: Minimum output point (x1, T1): The minimum basic assistance provided by the motor; Comfort pedaling point (x2, T2): The range of comfortable pedaling assistance provided by the motor; Hardest pedaling point (x3, T3): Powerful assistance provided by the motor; The controller automatically calculates all the unknown coefficients k1, b, and k2 in the piecewise function by solving the system of three equations; the solution formula is as follows: 。 4. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, Under the control of the controller, an adaptive assist mode is also included: When the first motor and the second motor are powered on, the controller controls the drive input of the second motor and adjusts the speed input of the first motor in conjunction with it, so that the system can transmit the output drive at a preset transmission ratio. The vehicle's output driving torque is entirely provided by the second motor, while the first motor regulates the input power to support the torque reaction force of the second motor in the power assist system.

5. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The first transmission assembly includes a first transmission component connected to the input shaft of an external input mechanism, a second transmission component connected to a second transmission system, and a third transmission component; The third transmission component is connected to the first and second transmission components in a transmission manner.

6. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The clutch is a one-way clutch.

7. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The second transmission assembly includes a fourth transmission component disposed in the second transmission system, a fifth transmission component connected to the first transmission system, and a sixth transmission component; The sixth transmission element is connected to the fourth and fifth transmission elements respectively.

8. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The main body of the first transmission system and the main body of the second transmission system are offset from each other along the direction of the foot pedal shaft of the foot pedal mechanism.

9. The power assist system with a built-in automatic transmission mid-mounted motor according to claim 1, characterized in that, The system also includes a power supply, which powers the controller, the first motor, and the second motor.

10. A vehicle employing a power assist system with a built-in automatic transmission mid-drive motor as described in any one of claims 1 to 9, wherein the power assist system with a built-in automatic transmission mid-drive motor provides power assistance to the vehicle.

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