Power-assisted driving system for electric bicycle

Abstract

According to the power-assisted driving system of the electric bicycle, firstly, a manufacturer is required to perform an actual road surface test on a target bicycle type in advance so as to establish a practical and reliable'maximum power-assisted torque limit value 'database, and then an efficient electric controller is used for extracting a target numerical value in the database according to an input condition; and the motor is commanded to provide the maximum limit of motor power-assisted torque of the vehicle according to the target value, and then the rider can drive the vehicle to walk at any time by adding a little treading force. In addition, an acceleration rotating handle which is similar to that of a traditional locomotive is arranged, so that a rider can adjust and set the power-assisted torque of the motor at any time at will, and the force distribution proportion of manpower and motor power assistance is changed. The system functions also consider various hard output driving conditions under the conditions of strong wind, steep slope climbing, load bearing and bad road surfaces, appropriate additional assistance can be provided in time to help riding, an implemented control mode requires that the system supplies force in advance, a rider can output power at any time and can obtain full motor assistance support, and the riding safety is improved. And the riding experience is more reasonable, more pleasant and more comfortable.

Description

Technical Field

[0001] This invention belongs to the field of electric-assisted bicycles and relates to an assist drive system for electric bicycles. Background Technology

[0002] This is an improvement to the invention patent granted by the State Intellectual Property Office of China, CN108516039 B. Based on that invention, the invention is given a completely new technical feature and effect through the means of "combined invention". The new technical solution does not require the expensive and easily damaged torque detector commonly used in electric-assist bicycles. The technical solution of this invention can meet the requirements of European and Japanese electric-assist bicycle regulations and Chinese national light electric bicycle regulations by using commercially available motor and electronic control components. This makes the power-assist drive system more cost-effective, more reliable and functional. Summary of the Invention

[0003] The purpose of this invention is to provide the following features for the power-assisted drive system of an electric bicycle: The manufacturer must conduct actual road tests on the target model beforehand and establish a database of "maximum assist torque limits," ensuring the highest reliability and practicality. The system controller can extract the target value from the database based on input requirements and command the motor to provide the maximum limit of assist torque according to the target value; the calculation process is simple and fast. The assist torque of this motor is determined by the real-time speed of the drive motor, always present and ready to work with human power to propel the vehicle, representing synchronous control that is effective and accurate. Furthermore, it features an accelerator lever similar to that of a traditional motorcycle, allowing the rider to freely adjust the motor's assist torque and vary the ratio of motor assistance to rider output at any time.

[0004] The present invention discloses a power-assisted drive system for an electric bicycle, which is implemented by the following technology. It includes: an electric bicycle with two or more wheels, comprising a handlebar, a frame, and a bottom bracket assembly. The vehicle includes one or more drive wheels and a battery unit; a motor unit that, according to electrical control commands, guides the power from the battery unit to drive the motor, generating rotational torque which is then transmitted to the drive wheels. A cadence signal generator detects the rider's pedaling motion on the bottom bracket assembly, driving the bicycle forward, and sends an ON signal; an electric assist control unit includes a human-machine interface, a set of input interfaces, a set of output interfaces, a software program, and a data processor that converts the inputs into a set of output control commands according to a pre-set program, including commands to drive the motor; and a brake lever with a power-off switch allows the rider to operate the braking function and provides a command to the electric assist control unit to cut off the drive of the torque motor during braking.

[0005] Furthermore, the power assist drive system for the electric bicycle includes a frame angle and terrain slope detection unit that can dynamically detect and obtain frame horizontal angle and terrain slope data at any time and input them into the power assist electric controller unit.

[0006] Furthermore, the power assist drive system for an electric bicycle includes a wind detection unit that can dynamically detect and obtain wind data in the direction of travel and input it to the power assist electric controller unit.

[0007] Furthermore, the power assist drive system for an electric bicycle includes a torque adjustment throttle that allows the user to operate and change the torque intensity ratio of the commands driving the torque motor.

[0008] Furthermore, the power assist drive system for an electric bicycle includes a load value input interface.

[0009] Furthermore, the power-assisted drive system for an electric bicycle includes a road condition input interface.

[0010] Furthermore, the power assist system for an electric bicycle includes a personalized motion mode setting interface that reduces the torque ratio and can change the direction of the torque vector.

[0011] Furthermore, the power assist system for an electric bicycle includes a cadence signal generator with an origin recognition signal. This generator can identify the absolute angle of rotation of the bottom bracket assembly, more precisely, the positive and negative directions of the angular displacement and rotation of the bottom bracket assembly. The cadence signal generator with the origin recognition signal can provide the pedaling angle position of the crank mounted on the bottom bracket, obtaining assist correction values ​​relative to different pedaling angles, making the rider's pedaling more ergonomic and comfortable. Attached Figure Description

[0012] Figure 1 The diagram shown is an external schematic of an electric-assisted bicycle based on the present invention.

[0013] Figure 2 The diagram shown is a hardware layout diagram of a power assist drive system for an electric bicycle according to the present invention.

[0014] Figure 3 The diagram shown is a simplified complementary filter configuration.

[0015] Figure 4 The diagram shown is a flowchart of the electric assist cycle program of the device of the present invention.

[0016] Figure 5The diagram shown is a flowchart for calculating the actual assist torque output value of the assist system of the present invention. Detailed Implementation

[0017] The present invention will now be further described with reference to the accompanying drawings; Figure 1 The diagram shows the appearance of an electric-assisted bicycle using the present invention. 1 is an electric bicycle, 2 is the handlebars, 3 at the end of the handlebars is a torque adjustment throttle, 4 is a brake lever with a power-off switch, 5 is the frame, and 6, the electrical control box, is fixed to its rear end. The box contains an electrical control unit, gyroscope, accelerometer, battery unit, input / output terminals, and internal wiring. This location is ideal for the electrical control box, as it is sheltered from sun and rain, and allows for ventilation. 7 is the pedals, 8 is the bottom bracket motor, 9 is an integrated hub motor driving the rear wheel, 10 is a digital anemometer, and 11 is a human-machine interface. In reality, only one of 8 and 9 needs to be installed on the actual vehicle; showing both together is for ease of explanation below. 5-1 is the bottom bracket assembly, and 5-2 is a cadence signal generator commonly used in electric-assisted bicycles.

[0018] Figure 2 The diagram shows the hardware layout of an electric bicycle's power assist system according to the present invention. 1-0 in the diagram represents a motor unit commonly used in electric-assist bicycles, which provides the required electrical power output according to the commands of the electrical controller. After the vehicle starts, in conjunction with the control of the power assist controller 2, different assist torques can be provided according to different vehicle speeds, helping the rider to maintain a constant speed, accelerate, and decelerate more effortlessly. When the parking brake is engaged, the drive wheel is off-leash, and the rider is riding an empty bike, a damping torque can be set for the motor. The rider can then pedal under the preset motor damping for indoor fitness exercises, charge the battery, and, when riding down a long, steep slope, the damping function can be used for auxiliary braking and recharging. When the rider is actually riding, rotating the torque adjustment throttle 3 changes the torque output ratio of the controller 2, similar to the throttle on a traditional motorcycle. This allows the rider to freely change the ratio of electric assist to pedaling force, making riding more enjoyable and relaxing. The frame angle / terrain slope detection unit can employ an angle sensing unit composed of a gyroscope, accelerometer, and analog-to-digital converter, which are widely used in electric self-balancing vehicles. Its design can be referenced in the appendix. Figure 3 A simplified complementary filter configuration diagram, in Figure 3 The system utilizes a complementary wave amplifier to fuse two sets of input signals, compensating for gyroscope drift and accelerometer dynamic errors. If the entire angle sensing unit shown in the diagram is fixed to the vehicle's frame, it can measure the vehicle's dynamic angle changes and terrain slope in real time, and transmit the terrain slope data traversed by the vehicle to... Figure 2The power assist controller 2 shown performs calculations to retrieve the maximum power assist or torque from the memory bank and command the motor to output the power assist torque to help the rider climb hills. In addition, it can also obtain vehicle acceleration and speed information and provide it to the controller. It is also possible to simply use a rotary decoder to measure the rotation speed of the bottom bracket or wheel and then convert it into vehicle speed. Alternatively, the feedback rotation speed signal of the drive motor wheel commonly used in electric-assisted bicycles can be used. Figure 2 The wind detection unit 5 shown can be a conventional digital wind meter, which is fixed on the frame facing the direction of the vehicle's movement to measure dynamic wind speed data and input it into the aforementioned power assist controller 2 for processing. Then, it retrieves the corresponding wind resistance assist torque from the memory bank and commands the motor to output an additional appropriate wind resistance assist torque to assist the rider in riding against the wind. Figure 2 The symbols 6-8 are not required standard equipment; they can be used as optional auxiliary enhancements. Figure 2 The load value input 6 shown is entered by the rider and provides additional assist torque to aid in heavy-load riding, making it easier. If no correction value is entered at startup, the system should execute the default value and start automatically. 7. Road condition input can be divided into general good road surface, (dirt) suboptimal road surface, or grassland high-resistance road surface for the rider to choose from. The purpose is to moderately increase the torque of the assist system to reduce the rider's physical burden. It is also an option. If no road surface selection is entered at startup, the system should execute the default value and start automatically. Figure 2 The option to personalize / reduce torque ratio / sport mode 8 is also available. Its function is to reduce the controller's built-in assist torque value by a fixed percentage, or even turn the assist into a reverse force to become a kind of riding resistance force, so that the rider can ride on flat ground as if going up a small slope or a steep slope, which can be used to exercise leg strength and fitness. Figure 2 The brake lever power-off switch 9 activates when the brake lever is operated, disconnecting the drive motor power to prevent overshoot. When the brake lever is not operated, the power-off switch is inactive and does not affect the power supply control of the assist controller. The power supply unit 2 drives the torque motor unit 1 to generate torque, which is then transmitted to the vehicle drive wheels. This torque is then combined with the torque from manual pedaling to propel the vehicle.

[0019] As for how to obtain the rated torque limit data of the power assist system and build a database, the vehicle manufacturer must conduct road tests on various types of vehicles according to the regulations of the local government where the product is sold. For each model, under various working and environmental conditions, such as load weight, road conditions, speed, slope, wind speed, etc., the output torque of the drive wheels from zero speed to just before starting is measured as the "starting torque value / Tst". And under the above combinations of environmental conditions, the "constant speed torque value / Tcr" of the drive wheels required to maintain a constant vehicle speed is measured. Thus, for example, to meet the European and Japanese regulations that the power assist ratio can be up to 75%, the above torque values ​​of Tst and Tcr are multiplied by 75% to obtain the "power assist torque output limit value Tmax" and stored in the controller as memory. When driving, the target value of the memory data is calibrated with the input information and the torque output of the motor (equivalent to the motor power value) is limited to not exceeding the limit value to comply with the regulations. This ensures that the vehicle cannot run purely on electric power and complies with the regulation that the motor assist system requires appropriate human pedaling to move the vehicle. The motor described above can be installed in the bottom bracket position of the bicycle, just like the bottom bracket motor assembly of a conventional electric bicycle, or it can be installed in the front or rear of the vehicle using a conventional integrated hub motor wheel assembly. The structure of the motor can be the same as that of current electric-assist bicycles.

[0020] Figure 4 The diagram shown is a flowchart of the electric assist cycle program of the device of the present invention. The diagram shows that when the rider turns on the power switch and activates the vehicle's electrical system, the power assist system begins to power on and enters the initialization phase. It receives data on vehicle load and ground conditions. If there are no signals indicating a halt to the cycle, such as excessive waiting time for the power assist cycle to start, or the brake lever power switch being activated, the system officially enters the power assist cycle. The first step involves collecting signals such as vehicle speed, terrain gradient, and wind speed coefficient, and inputting them to the controller's main chip for processing. This allows the system to retrieve the corresponding "allowable assist torque value" and "wind resistance compensation torque value" from the memory bank. The sum of these two values, multiplied by the "output % value of the rider's torque adjustment throttle," becomes the "actual output assist torque value." This value is then used to activate the power converter, directing the power from the battery unit to supply the torque motor output controller with the torque required by the vehicle's drive wheels. It can be seen that this motor assist torque is applied beforehand. When the rider pedals the vehicle's bottom bracket assembly, effectively driving the vehicle forward, it triggers the cadence signal generator 5-2 to generate an ON signal and connect. Figure 4The assist torque value shown in 4-12 is transmitted to the drive wheel via the power converter shown in 4-15. Thus, the assist torque 4-12, combined with the pedaling torque in 4-16, drives the vehicle. The "Zeroing Inclination or Memory Value" option shown in the diagram is a function selection option. When the vehicle's load is extremely uneven, or the frame tilts significantly, the system will automatically prompt a deviation from the gyroscope's reference setting tolerance. The rider can then press the "Zeroing Inclination" button to establish a new horizontal reference for the gyroscope, correcting for the actual incline data during riding. This function should be automatically cleared when the vehicle is turned off. The "Memory Value" button is used to restore the factory default settings. Therefore, under the continuous operation control of the above assist cycle, and in conjunction with the wind force, terrain slope, and vehicle speed, the motor will automatically provide appropriate assistance to help the rider. The rider can also operate the torque adjustment throttle to freely change the magnitude of the motor's assistance. In addition, since the controlled object / vehicle is a dynamic and potentially extremely unstable continuous motion, fortunately, various effective motion control technologies are available on the open market. For example, by using the classic PID control method, combined with a control cycle operation frequency of 40 to 100 times per second for data acquisition and output, various noises, spikes, and smooth input and output information can be eliminated, effectively driving the vehicle to meet the riding requirements of any discerning rider.

[0021] Figure 5 The diagram shows the calculation flowchart of the actual assist torque output value of the power assist system of the present invention. In the process of obtaining the actual assist torque output value, firstly, input 1 (ground conditions and load conditions). If no input is made, the system will execute according to the default value. Then, the controller chip finds the corresponding memory 2 (allowable assist torque value database) according to the input. Then, according to the data 3-1 (slope) and 3-2 (drive wheel speed) automatically measured by the control system, the intersection point is calibrated to determine the allowable assist torque value. On the other hand, the wind force correction value 4 is found according to the measured wind force data. The value obtained by adding 3 and 4 is multiplied by the percentage of the rider's torque adjustment throttle 5. Next, when the rider pedals the bottom bracket to effectively drive the vehicle, the cadence signal generator sends an ON signal, guiding the assist torque value 5 to become 6 (actual torque output value of the drive wheel). Figure 4 The ON / OFF switch of the mid-pedal frequency signal generator can also be installed on the torque adjustment throttle 5. The aforementioned power assist torque limit database and calculation acquisition process can be programmed using commercially available software and pre- and post-calculation methods; therefore, all conventional technologies applied fall within the scope of this invention.

Claims

1. The present invention provides a power-assisted drive system for an electric bicycle, characterized in that... It includes: An electric bicycle with two or more wheels (1), including a handlebar (2), a frame (5), a bottom bracket assembly (5-1), one or more vehicle drive wheels (9) and a battery unit; A motor unit, including one or more bicycle motors, can be activated by electrical control commands. The electric power from the battery unit drives the motor assembly to generate rotational torque, which is then transmitted to the vehicle's drive wheels (9). A data memory that stores the electric bicycle under different working environments (such as load weight, road surface conditions). Data obtained from road tests of the electric bicycle (1) including conditions, speed, gradient, and wind speed, such as the starting torque value from zero speed to just before starting and the allowable assist torque data of the constant speed torque value of the vehicle drive wheels required to maintain a constant speed; A cadence signal generator (5-2) is used to detect when the rider pedals the drive motor of the bottom bracket assembly (5-1). The state of the bicycle (1) is such that it sends an ON signal when it is effectively driving the vehicle forward; An electric assist control unit (6) includes a human-machine interface, a set of input interfaces, a set of output interfaces, a set of program software, and a data processor that can convert inputs into a set of output control commands according to a set program. The control commands include commands to drive the motor (8). The generation of the motor drive command is as follows: When the electric assist drive system for the electric bicycle is powered on (4-0), the electric assist drive system starts to work. First, the electric assist drive system accepts input load or internal value (4-2), ground condition or internal value (4-3), and slope zeroing or memory value (4-4) to complete the initialization of the electric assist drive system (4-5). At this time, if there is no input to stop the operation of the electric assist drive system (4-20), the electric assist drive system officially starts the working cycle (4-6). Therefore, the work cycle (4-6) immediately enters the process of collecting vehicle speed, vehicle gradient, and anemometer reading (4-10). Then, the power assist system will search for the corresponding allowable assist torque value and wind force compensation torque value (4-11) from the database based on the above-mentioned vehicle speed, vehicle gradient, and anemometer reading (4-10). In conjunction with the effective drive signal ON of the cadence signal generator (5-2), the power assist system guides the power supply unit (4-1) to convert electrical energy into kinetic energy to drive the motor and vehicle drive wheels (4-17). In this way, one single cycle of the power assist system is completed. At this time, the power assist system will automatically start the work cycle (4-6) again and again until it receives the stop (4-20) input and stops the operation of the work cycle (4-6).

2. The power assist drive system for an electric bicycle according to claim 1, characterized in that... It package Includes: a torque adjustment throttle (4-13) connected to the power assist control unit, which, when turned, adjusts the actual output power assist torque value (4-12) according to the percentage of the radian turned.

3. The power assist drive system for an electric bicycle according to claim 1, characterized in that... It package Includes: a cadence signal generator, which also detects the angular displacement state of the rider pedaling the bottom bracket assembly (5-1) and emits the angular displacement signal of the bottom bracket assembly when the vehicle is moving forward.

Images