PEDAL CADENCE LAW WITH MODIFIED RANKS OF AN ELECTRICALLY ASSISTED BICYCLE MOTOR WITH INTEGRATED GEARBOX

Abstract

The invention relates to a device (1) for controlling the pedaling cadence of an electrically assisted bicycle (1), comprising: at least one gearbox system (20), comprising maximum (rgb_max) and minimum (rgb_min) gearbox ratios; data processing means (21) for: receiving information on the rotation speed of the crankset, called the pedal cadence setpoint, and information on the measured wheel cadence; calculating two wheel cadence values, including: a smaller wheel cadence value, from at least the value of the minimum gearbox ratio and the pedal cadence setpoint, a larger wheel cadence value, from at least the value of the maximum gearbox ratio and the pedal cadence setpoint. calculating, from at least said measured wheel cadence information: at least one crankset rotation speed command, at least one gearbox ratio command. Figure 1

Description

Title of the invention: PEDAL CADENCE LAW WITH MODIFIED SLOPES OF AN ELECTRICALLY ASSISTED BICYCLE MOTOR WITH INTEGRATED GEARBOX Technical field

[0001] The field of the invention is that of control laws for embedded systems and algorithms. The field of application concerns electrically assisted bicycle systems comprising a gearbox system, and more generally, continuous speed transmission systems (Continuously Variable Transmission or CVT). STATE OF THE PRIOR ART

[0002] Electric bikes represent a significant advance in urban mobility and in the world of sports cycling. Indeed, they offer a clean, efficient and often faster alternative to traditional means of transport. They are equipped with electric motors that assist pedaling, making it possible to cover different terrains and longer distances without excessive fatigue. This makes it possible to overcome obstacles such as steep slopes or winding terrain with less effort. This advancement allows the user to concentrate on technique and enjoy new routes. In addition, improved suspensions, ergonomic saddles and the ability to adjust pedaling effort according to the cyclist's needs contribute to a more enjoyable ride.

[0003] But, in an urban environment, stops are very frequent and the many starts can be tiring, which makes the cycling experience more demanding. Whereas, in a sporting environment, it would be desirable to maintain or improve comfort, while meeting the need to practice a sporting activity requiring a certain degree of effort.

[0004] In this context, the problem arises for an electric bicycle user in an urban environment, of having pedal assistance involving less effort when starting off or at low cycling speed. Whereas, for a sports user, the problem arises of obtaining assistance at the cost of a higher pedaling effort, while maintaining or improving the efficiency and power of the assistance obtained. More precisely, the problem arises, for the sports cyclist, of being able to adjust the assistance according to the effort exerted. Similarly, a maximum power threshold not to be exceeded by the electric assistance could be envisaged.

[0005] Thus, the problem arises of adapting the pedaling effort according to the needs of the cyclist and according to the traffic environment by choosing different levels of electric assistance. These different levels could provide faster, slower, or more assistance depending on individual needs. Statement of the invention

[0006] The invention aims to remedy at least in part the drawbacks of the prior art, and more particularly to propose a device which can be adapted to the needs of each cyclist.

[0007] For this purpose, an object of the invention relates to a device for controlling the pedaling cadence of an electrically assisted bicycle, this device comprising: • At least one gearbox system, including a maximum gearbox ratio (rgb_max) and a minimum gearbox ratio (rgb_min); • data processing means, which can be integrated into the gearbox, specially programmed for: • receive information on the rotation speed of the crankset (wp_target), called the pedal cadence setpoint, and information on the rotation speed of the bicycle wheel (ww), called the measured wheel cadence; • calculate two wheel cadence values, including: • a smallest wheel cadence value (WC1), called the first operating point, and calculated from at least the value of the minimum gearbox ratio and the value of the pedal cadence setpoint, • a higher wheel cadence value (WC2), called the second operating point, and calculated from at least the value of the maximum gearbox ratio and the value of the pedal cadence setpoint. Thus a user can select a pedal cadence setpoint, the data processing means calculating two wheel cadence values ​​WC1 and WC2.

[0008] The data processing means may further be specially programmed to:

[0009] * calculate a crank rotation speed command (wp_command), called pedal cadence control,

[0010] * and / or a gearbox ratio command (rgb_command), called command gearbox ratio, from said measured wheel cadence information, for example:

[0011] - for at least one measured wheel cadence less than WC1;

[0012] - and / or for at least one measured wheel cadence between WC1 and WC2;

[0013] - and / or for at least one measured wheel cadence greater than WC2.

[0014] The invention allows, for example, for a user of an electric bicycle in an urban environment, to have assistance involving a lower pedaling cadence when starting off or at low bicycle speed; for a sports user, it allows assistance to be obtained at the cost of a higher pedaling cadence.

[0015] According to one embodiment:

[0016] - the pedal cadence control comprises a zone, or first zone, of func operation, defined for a measured wheel cadence not zero and lower than the first operating point, the means being programmed to calculate:

[0017] - a pedal cadence control, variable and lower than the cadence setpoint pedal from at least the constant minimum gearbox ratio value;

[0018] - and / or a constant and equal gear ratio control or gear ratio minimum, or variable, from at least the constant minimum gearbox ratio value.

[0019] - and / or the law of the pedal cadence includes a zone, or second zone, of func operation, defined for a measured wheel cadence between the first and second operating points, the means being programmed to calculate:

[0020] - a pedal cadence command:

[0021] - either constant and equal to the pedal cadence setpoint;

[0022] - either variable, from at least the value of the pedal cadence setpoint; in this case, it can be variable according to a slope, called the pedal cadence slope, being greater than or less than or equal to the pedal cadence setpoint; alternatively, it can be non-linear;

[0023] - and / or a variable gearbox ratio control, between the value minimum gearbox ratio and maximum gearbox ratio value.

[0024] In a device according to the invention, the gearbox ratio control may comprise a second operating zone, defined for a measured wheel cadence between the first and second operating points, the means being programmed to calculate a gearbox ratio control, variable between the minimum gearbox ratio and the maximum gearbox ratio.

[0025] The data processing means can further be programmed to determine at least one maximum wheel cadence value beyond which the pedal cadence control is limited to a predetermined maximum value, called the maximum pedal cadence control, said maximum wheel cadence value being determined from the maximum ratio control value and the maximum pedal cadence control.

[0026] The law of pedal cadence can therefore include:

[0027] - a zone, or third zone, of operation, defined for a wheel cadence measured between the second operating point and the maximum wheel cadence value, the data processing means being programmed to calculate:

[0028] - a variable pedal cadence control, greater than the pedal cadence calculated during the second operating zone, from at least the constant maximum ratio value;

[0029] - and / or a gearbox ratio control, constant and equal to the ratio of maximum box, or variable, from at least the constant maximum ratio value. ;

[0030] - and / or a zone, or fourth zone, of operation, defined for a rate measured wheel greater than the maximum wheel cadence value, the data processing means being programmed to calculate:

[0031] - a constant pedal cadence command, greater than the pedal cadence variable calculated during the third operating zone, and equal to the maximum pedal cadence command;

[0032] - and / or a gearbox ratio control, constant and equal to the maximum gearbox ratio, or variable, from at least the constant maximum ratio value.

[0033] In a device according to the invention, the data processing means can be programmed to vary the minimum ratio value of the gearbox, for example to vary the value of the first operating point.

[0034] In a device according to the invention, the data processing means can be programmed to calculate the second operating point as a function, in addition, of a slope, called the slope of the pedal cadence.

[0035] An electrical assistance device according to the invention may further comprise: • At least one system or means of data collection to determine at least one rotation speed of the pedal, called pedal cadence setpoint; • means, for example at least one sensor, for measuring the rotation speed of a wheel of the bicycle, called measured wheel cadence. The invention also relates to an electrically assisted bicycle comprising a device according to the invention, as defined above or in the present application.

[0036] The invention also relates to a method for controlling the pedaling cadence of a bicycle or an electrically assisted bicycle, implementing a device according to the invention.

[0037] The invention also relates to a method for controlling the pedaling cadence of an electrically assisted bicycle, for example using a device according to the invention, comprising at least the following steps: • data collection to receive information in a gearbox on the rotation speed of the pedal crank, called the pedal cadence setpoint, and the rotation speed of the bicycle wheel, called the measured wheel cadence, the gearbox speed, including a maximum gearbox ratio and a minimum gearbox ratio; • data processing using data processing means, integrated into the gearbox, allowing the calculation of at least: • Two wheel cadence values, including: • a smallest wheel cadence value, called the first operating point and determined from at least the value of the minimum gearbox ratio and the pedal cadence setpoint, • a higher wheel cadence value, called the second operating point and determined from at least the maximum gearbox ratio and the pedal cadence setpoint. In a method according to the invention, the data processing means can further be programmed to calculate or determine:

[0038] -at least one pedal rotation speed control, called pedal cadence control;

[0039] - and / or at least one gearbox ratio control, called gearbox control of speeds;

[0040] - and / or at least one maximum wheel cadence value beyond which the pedal cadence control is limited to a predetermined maximum value, called the maximum pedal cadence control, said maximum wheel cadence value being determined from the maximum gearbox ratio value and the maximum pedal cadence control. Brief description of the drawings

[0041] Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which: • [Fig.l] is a schematic view of an electric assistance device for a bicycle • [Fig.2] is an example of an electrically assisted bicycle; • figures 3A and 3B are curves illustrating the variation of the pedal cadence relative to the wheel cadence according to a first embodiment; • figures 4A and 4B are curves illustrating the variation of the pedal cadence relative to the wheel cadence according to a second embodiment; • [Fig.5] is an example of a functional diagram of an embodiment of the invention. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0042] In the figures and in the remainder of the description, the same references represent identical or similar elements. Furthermore, the different elements are not shown to scale so as to enhance the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and may be combined with each other. Unless otherwise indicated, the terms "substantially", "approximately", "of the order of" mean to within 10%. Furthermore, the terms "between ... and..." and equivalent mean that the limits are included, unless otherwise indicated.

[0043] The invention relates in particular to a device 1 and a method for controlling the pedaling cadence of an electrically assisted bicycle. The invention makes it possible to adapt the pedaling cadence based on different instructions from the user of such a bicycle during urban use or sports use. This device 1 can be integrated into the bicycle. As illustrated in [Fig.l], according to an exemplary embodiment, it comprises a human-machine interface system 10, a gearbox system 20 and a bicycle speed measurement system 30. Digital means 21 are also provided (for example a processor or a microprocessor or an ASIC programmed according to an embedded software code). In the example shown in [Fig.l], the digital means 21 are part of the system 20. Alternatively, they are external to this system 20, while ensuring the same functions. For example, they can be integrated into the means 10.

[0044] The ratio between the wheel cadence and the pedal cadence is called the gearbox ratio value. This ratio determines how many pedal rotations produce one wheel rotation. A gearbox ratio equal to 1 makes it possible to make one wheel revolution for one pedal revolution made. The gearbox 20 has a minimum value of this ratio (or minimum ratio value (rgb_min)) and a maximum value of this ratio (or maximum ratio value (rgb_max)). The area of ​​use is between a system configuration at the minimum ratio value and a configuration at the maximum gearbox ratio value.

[0045] The human-machine interface system 10 communicates with the means 21, for example via an analog-to-digital converter (ADC). In addition, the means 21 are connected to the analog bicycle speed measurement system 30.

[0046] Particular embodiments will be described relating to different behaviors of a device or method according to the invention. These embodiments can be adapted to all electrically assisted bicycles comprising a gearbox system and to Continuously Variable Transmission (CVT) systems.

[0047] The human-machine interface system 10 comprises means 11, for example a selector, for example again a button, for selecting the pedal cadence setpoint and digital means for converting the selection made by this selector into a signal. These means 11 make it possible to record the pedal cadence level desired by the user. For example, the user can select a desired pedal cadence level on a scale, which can be discretized, between a minimum value and a maximum value, for example again on a scale of 1 to 10. The machine interface system 10 sends to the means 21 a digital signal wp_target, image of the setpoint selected by the user using the means 11. This digital signal wp_target makes it possible to set, among other things, a pedal rotation speed setpoint, called pedal cadence command wp_command.In other words, from the pedal cadence setpoint wp_target, the system determines a pedal cadence command wp_command.

[0048] Alternatively, the system may automatically determine this signal without the help of the user; (in this case, the interface 10 may be provided with means, for example a Bluetooth or LTE chip, to receive wp_target from a data center or from a mobile phone of the user):

[0049] - for example, on a cloud server, with embedded software allowing calculation one or more optimal pedaling cadences for the user, based on previously collected user data;

[0050] - or, manually by the user, for example by direct selection of a pedal cadence instruction via a mobile phone application or web portal.

[0051] Furthermore, this wp_target signal can be determined at various times:

[0052] - at startup, or at another time to set a new variable value of pedal cadence instruction;

[0053] - or when the bicycle stops, for example to record the last value used;

[0054] - or continuously, or at more or less regular intervals, for example by wireless transmission between the telephone and the bicycle (via the interface 10), or between a web server and the bicycle, or via an IOT unit; in the latter case (IOT unit), the interface 10 may include means (for example different chips) allowing the use of different communication protocols.

[0055] The bicycle speed measuring system 30 comprises one or more sensors for measuring, for example, the bicycle speed or a measured bicycle wheel cadence (ww). For example, the sensor may be of the type comprising a magnet or an accelerometer which may be located in a wheel, for example the rear wheel (on or in the hub, or in a spoke, or in a brake disc). Other sensors may be used, allowing indirect measurement, for example:

[0056] - by an inertial unit on an electronic card from the speed of the bicycle;

[0057] - or, when the pedal assembly drives the gearbox, by measuring the speed of the assistance motor or by measuring the pedal cadence (known gearbox ratio);

[0058] - or by GPS sensor(s) allowing the speed of the bicycle to be calculated.

[0059] The means 21 therefore have means, for example one or more input(s), for receiving:

[0060] - information on the rotation speed of the pedal, called measured pedal cadence wp_measure,

[0061] - and information on the rotation speed of the bicycle wheel, called wheel cadence measured (ww).

[0062] The digital means 21 receive the pedal rotation speed instruction and transform it into a pedal cadence command (wp_command) and a gearbox ratio command rgb_command. The electric assistance motor(s), for example two motors belonging to two geared motors, is / are controlled in speed and torque. They use the wp_command and rgb_command commands as input data in order to determine the desired operation for a given bicycle speed or a measured wheel cadence. The torque and speed commands of this / these motor(s) are a function of the pedal cadence and gearbox ratio commands.

[0063] The means 21 define the pedal cadence (wp_command) as well as the gearbox ratio command (rgb_command) between the minimum ratio value (rgb_min) and the maximum ratio value (rgb_max).

[0064] The rgb_command command makes it possible to adjust the variations of the pedal cadence control relative to the wheel cadence. As understood from [Fig.5], the wp_target and wheel cadence (ww) data are supplied to the means 21, which calculate the wp-command and rgb_command data which adjust the pedaling cadence (to generate the motor control law). This is a different functionality from that dedicated to adjusting the behavior and the level of electric assistance, even if data such as the control laws of the motor(s) can be used for the electric assistance, as indicated in [Fig.5] (in this figure, broken lines correspond to functionalities peripheral to the invention and / or which implement all or part of the data obtained according to the invention).

[0065] Document WO2023180643 describes aspects of a controlled transmission powertrain for an electrically assisted bicycle, which can be used in the context of the present invention.

[0066] The gearbox ratios are adjustable automatically and / or mechanically using a set of pulleys or by means of a motor driving an epicyclic reducer of so as to modify its transmission ratio (on this subject one can refer to document WO2023180643). The minimum gearbox ratio value can be modified digitally or mechanically by varying the transmission ratio between the gearbox system and the wheel.

[0067] The torque and speed controls of the electric assistance motor(s) are a function of the pedal cadence and gearbox ratio controls.

[0068] The means 21 are configured or programmed according to an embedded software code making it possible to implement a method according to the invention.

[0069] For example, for a given pedal cadence setpoint, it is possible to determine two corresponding wheel cadence values ​​(WC1 and WC2) (from the moment when rgb_min and rgb_max are fixed, WC1 and WC2 are derived from the pedal cadence setpoint) which are fixed and between which the means code 21 will ensure the pedal cadence (wp_command) and gearbox ratio (rgb_command) commands. For example:

[0070] - in a first embodiment: the pedal cadence control is constant and equal to the pedal cadence setpoint (wp_target), and the gearbox ratio command varies between rgb_min and rgb_max;

[0071] - in a second embodiment: the pedal cadence control is variable following a given slope, and greater than or equal to the pedal cadence setpoint (wp_target) or less than or equal to the pedal cadence setpoint (wp_target). We will call this slope the pedal cadence slope. The gearbox ratio control varies between rgb_min and rgb_max.

[0072] The two wheel cadence values ​​WC1 and WC2 define a first and second operating point, the first (WC1) being lower than the second (WC2).

[0073] These operating points can delimit at least two operating zones. As illustrated in [Fig.3A], representing a first embodiment, when the measured wheel cadence is lower than the predetermined value of the first operating point (WC1), then the pedal cadence command wp_command, sent by the means 21, is variable and lower than the pedal cadence setpoint wp_target. In this first zone, the pedal cadence command is determined from the minimum ratio value of the gearbox and the measured wheel rotation cadence. Indeed, the slope of wp_command is equal to the inverse of rgb_min.

[0074] In the second operating zone, the measured wheel cadence is between the two operating points WC1 and WC2. The pedal cadence command wp_command is constant (here, the pedal cadence slope is therefore zero) and equal to the pedal cadence setpoint. The gearbox ratio command rgb_command varies between the minimum ratio value rgb_min and the maximum ratio value rgb_max. This gearbox ratio value rgb is then determined by the speed of the bicycle or by the measured wheel cadence (this is the inverse of the slope of the line D represented in [Fig.3A], this line passing through the origin and through the point with coordinates ww and wp_target).

[0075] According to a more particular embodiment, it is also possible, for a given pedal cadence setpoint, to determine a wheel cadence value WCmax (see [Fig.3A]), greater than WC2, beyond which the pedal cadence command is limited to a maximum value Cmax defined by the program or calculated from user data or selected by the user. This wheel cadence value WCmax constitutes a third operating point.

[0076] A third operating zone can then be defined, the measured wheel cadence being between the second operating point WC2 and the third operating point WCmax, the pedal cadence command then being variable, greater than the pedal cadence calculated during the second operating zone. In the third operating zone, the pedal cadence command is determined from the measured wheel cadence and the constant maximum gearbox ratio value. Indeed, the slope of the pedal cadence command is equal to the inverse of rgb_max.

[0077] Finally, when the measured wheel cadence is greater than the third operating point WCmax, the pedal cadence command may be constant and greater than that calculated during the third operating zone. The command may then have a value equal to the predetermined maximum pedal cadence Cmax. The gearbox ratio will then be equal to a maximum ratio constant.

[0078] The means 21 can be programmed to implement calculation steps corresponding to the steps described above. An example of an algorithm for implementing these steps is as follows: Function of (WC1,WC2 ,WCHax . rgb_command swp_cow^ = f(»w,wp_target• rgb_min, rgbuaax ,Cw If wpttargét >= Cmax wp_target = Cmax End if WC1 = rgbjiin * wp_target WC2 = rgb^max * wp-target WCmax = rgb_nax * CsnàX If ww < ViCl rgb^ccinwarid = rgh_min Wpjcommand = vav / rgb„coBimand Elseî fw <' WC2 rgb_coîrasand = svw / wp_target wp_coaiMand = wp_target Elseïf ww < WCmaX rgb_cosn <isahd = rgb_wax wp^cprçmànd - ww / rgb_ccf!mtand EIse rgb_cô!Mand = rgb_max ®p_coæiiiand - Cmax Endif If wp_cownand > - Cn>ax wp_comnsand = Cmax Encti f End Function

[0079] The first embodiment described above in connection with [Fig.3A] makes it possible to operate at constant pedal cadence in one or more, for example four, operating zone(s). As described previously, for a given pedal cadence setpoint, the corresponding operating points WC1 and WC2 can be identified (they are the intersection of the straight line which is at this pedal cadence setpoint level and the 2 straight lines of slopes given respectively by the inverse of rgb_min and the inverse of rgb_max). Thus, from this constant pedal cadence law, it is possible to create a variation of possible behaviors according to the pedal cadence setpoint wp_target, requested by the user or identified or given by the system. [Fig.3B] represents for example four possible behaviors of the system from four pedal cadence setpoint values ​​(identified in the figure respectively by Value 1, Value 2, Value 3, Value 4). Depending on the pedal cadence setpoint determined or selected, one of these behaviors will be implemented.

[0080] A second embodiment, called modified slope pedal cadence law, is shown in Figures 4A and 4B. This embodiment provides many advantages over the first. For example, it allows, in the first operating zone, to prevent the user from feeling a sensation of pedaling too fast at start-up in the case where the minimum ratio value is too low. Similarly, it allows, during the second operating zone, to prevent the user from feeling a limitation in his pedaling cadence when the pedal cadence setpoint is reached and that he wishes to increase the speed of the bicycle. Indeed, in order to reduce these perceptions, this second embodiment makes it possible to modify, here reduce, the slope of the first operating zone, and / or to modify, here increase, the slope of the pedaling cadence control of the second operating zone, called the pedal cadence slope ([Fig.4A]).

[0081] To do this, each pedal cadence setpoint value wp_target is assigned a new minimum ratio value rgb_min_mod, as well as a pedal cadence slope value plateau_slope. This pedal cadence slope value was zero in the first embodiment, it will be strictly positive in this second embodiment. Other embodiments can be considered without modifying the slope or, for example:

[0082] - by changing the position of the bearing;

[0083] - by applying a non-linear law instead of a slope;

[0084] It is thus possible to generate new values ​​of the operating points (WCl_mod_p, WC2_mod_p) and of the control torque (rgb_command, wp_command).

[0085] These modifications reset the operating point values ​​(WCl_mod_p, WC2_mod_p) for each pedal cadence setpoint value. The operating points are calculated based on the modified minimum gearbox ratio value, as well as the pedal cadence slope value. The means 21 may be programmed to implement this aspect, for example according to the following algorithm: Funrtiotiof (rgbjntnjnod>plateau_slope.wp_commandjnod.WCljnod_p,W'C2jnodjj) = f(wpjargêtWC2.WCmax.ww) Swifch case (wp_target) Case 1: Defne Variable rgbjnin_mod=rgb_mln_mad_case_l Define Variable plateai!_siope=plateaujdûpe_case_ I Case n: Defme Variable j'gKmin_mod=rgb_nùn_niodxase_n Befllié Variable plateau_slope=plateàu_slope_caséji End WCl jno <Lp = rçÿxjninjnod * wp.target If ww < WCmax WC2_tpod_p = (WC2 - plateaiLsiope * rgbjnax ♦ WCl.mod_p) / (1 - plate-slope * rgbjnax) Else WC2_mod_p = WCniax Endif End Funeticiîi|

[0086] As a result, the pedal cadence control parameters wp_command and gearbox ratio rgb_command are recalculated in the first two operating zones (see the lines “If ww < WCl_mod_p” and “Else if ww < WC2_mod_p”) as illustrated in the following algorithm or method: FuncUon of (wp.command _mod.rgb_mod) =f(ww,wp_tai^etWC2,^b_max,WCi»ax,tmax,WCl_mod_p,WC2jnod_p,i^b_iia!n.iBod) If wp.coHitiiand >= Cmax wp_coBwiancLnK>d = Cmax Efee If w < WC î_mod_p wp_command_œod = ww / rgbjninjnod rgb_med = rgb jmrLmod Eîsejfww < WC2_mod_p wp.comtnandjnod=wp_target + ( w - WCljnod-p ) / ( WC2jnod_p - WCl_mod_p ) * ( WC2j»od_p - WC2 ) / rgbjnax sgb_mcd = w / wp-CommahtLmod Elseif ww < WCmax wp,comman <lmod = ww rgbjnax rgb_med="rgb_max" else wp.comtnandjnod="Cmax" rgbjnod="rgb_max" endif Endif Eiid Fitncfitm

[0087] In the first operating zone, there is an increase in the minimum gear ratio rgb_min. We define values ​​of rgb_min_mod that are all the greater as the pedal cadence setpoint wp_target is low, by making rgb_min tend towards rgb_max. We can thus suggest to the user, at low bike speed, to pedal less quickly in urban use (gear ratio closer to rgb_max) to obtain assistance; and more quickly in sport use (gear ratio closer to rgb_min) according to the value of the pedal cadence setpoint wp_target. In other words, • for a low bike speed ww and low values ​​of wp_target, the user needs to pedal less quickly to obtain assistance: this is urban use. • for a low ww bike speed but for high wp_target values, the user needs to pedal faster to get assistance: this is sporting use.

[0088] A variation of rgb_min can be obtained:

[0089] - by software: by varying the speed of a motor of a geared motor comprising by example an epicyclic train;

[0090] - or by mechanical means: by varying the transmission ratio between the system of gearbox and wheel (modification of chainring / pinion with chain or diameters with belt).

[0091] In the second operating zone, the introduction of the plateau_slope slope on the wp_command pedal cadence command makes it possible to obtain certain characteristics. The objective is to ask the user, at a higher bike speed, to pedal faster than the constant pedal cadence setpoint, whether in urban use or in sport use. In urban use, the wp_target setpoint being low and rgb_min_mod approaching rgb_max, the increase in the pedal cadence command (wp_command) on the constant pedal cadence plateau is lower than in urban use. sport. In other words, for a higher ww bike speed, with low wp_target values, the user needs to pedal faster to increase the bike's speed: urban use. Similarly, for a high bike speed but for high wp_target values, the user needs to pedal even faster to increase the bike's speed: sport use.

[0092] [Fig.4B] represents, for example, 4 possible behaviors of the system from four pedal cadence setpoint values.

[0093] Four-zone operation has been described previously. Additional operating zones may be added and incorporated into the invention. Furthermore, single-zone, two-zone, or three-zone operation is also possible. It is sufficient to omit certain operating points.

[0094] For example, one can consider an operation with three zones delimited by WC1 and WC2 (below WC1, between WC1 and WC2 and above WC2). A fourth zone is defined by WCmax to operate the system in the entire possible speed range, but could be managed by another software block.

[0095] Furthermore, a constant gearbox ratio control law can have a single zone if Cmax is not considered or two zones if Cmax is considered.

[0096] Three-zone operation is also possible, with the same example of constant gearbox ratio in the first zone, a second zone which would connect WC1 to WCmax, then a third zone at constant cadence equal to Cmax.

[0097] Other types of control laws are possible and can be implemented within the framework of the present invention.

[0098]

[0099] As shown in [Fig.2], a bicycle to which the invention can be applied comprises a frame 16 (composed of several assembled tubes), a front wheel 4, a rear wheel 6, a handlebar 8 connected to the front wheel by a fork 12, a saddle 14.

[0100] The control system 1 can be distributed between the human-machine interface system on the handlebar 8 and the gearbox system integrated into the motorization system; the bicycle speed measurement system 30 can be positioned at different locations on the bicycle.

[0101] For example, the human-machine interface system 10 can be fixed on the handlebar 8, but other positions are possible, for example on a tube of the frame or inside the engine or gearbox (20).

[0102] The bicycle also comprises a crankset, which comprises two pedals 22, 24, connected by cranks 22', 24' to an axle which enters a housing. The action of the cyclist on the crankset drives a chain 28. In the case of an electrically assisted bicycle, a motorization system, comprising two geared motors and the gearbox speed (20) are housed in a casing 20' through which the crankset axle passes. The casing 20' may also contain the control means 21 (in broken lines in [Fig.2]), which make it possible to control the assistance provided to the cyclist by the electric motor. Other solutions have been mentioned above for these means 21. Reference 32 designates an electric battery. In addition, the bicycle speed measuring system 30 may be positioned in different locations, for example on, or in connection or in interaction with, a wheel or inside the motor or gearbox (20).

[0103] According to an exemplary embodiment, the gearbox can be integrated into the motorization system, comprising 2 geared motors, one of these geared motors being able to provide the gearbox function.< / lmod>

Claims

Claims

1. Device (1) for controlling the pedaling cadence of an electrically assisted bicycle (1), the device comprising: • at least one gearbox system (20), comprising a maximum gearbox ratio (rgb_max) and a minimum gearbox ratio (rgb_min); • data processing means (21) specially programmed to: • receive information on the rotation speed of the pedal assembly, called the pedal cadence setpoint, and information on the rotation speed of the bicycle wheel, called the measured wheel cadence; • calculate two wheel cadence values, including: • a smallest wheel cadence value (WC1), called the first operating point, calculated from at least the value of the minimum gearbox ratio and the pedal cadence setpoint, • a higher wheel cadence value (WC2), called the second operating point, calculated from at least the value of the maximum gearbox ratio and the pedal cadence setpoint; • calculate, from at least said measured wheel cadence information: *a pedal rotation speed command, called pedal cadence command; * a gearbox ratio control, called a gearbox ratio control.

2. Device according to claim 1, the pedal cadence control comprising a first operating zone, defined for a measured wheel cadence which is not zero and lower than the first operating point, the means (21) being programmed to calculate a pedal cadence control which is variable and lower than the pedal cadence setpoint from at least the minimum ratio value constant.

3. Device according to claim 1 or 2, the gearbox ratio control comprising a first operating zone, defined for a measured wheel cadence which is not zero and lower than the first operating point, the means (21) being programmed to calculate a gearbox ratio control which is constant and equal to the minimum gearbox ratio, or variable, from at least the constant minimum ratio value.

4. Device according to one of claims 1 to 3, the pedal cadence control comprising a second operating zone, defined for a measured wheel cadence between the first and second operating points, the means (21) being programmed to calculate a pedal cadence control: - constant and equal to the pedal cadence setpoint; - or variable, from at least the value of the pedal cadence setpoint.

5. Device according to claim 4, the means (21) being programmed to calculate a pedal cadence command: - variable following a slope, called the pedal cadence slope, being greater than or less than or equal to the pedal cadence setpoint; - or non-linear.

6. Device according to one of claims 1 to 5, the gearbox ratio control comprising a second operating zone, defined for a measured wheel cadence between the first and second operating points, the means (21) being programmed to calculate a gearbox ratio control, variable between the minimum gearbox ratio and the maximum gearbox ratio.

7. Device according to one of claims 1 to 6, the data processing means (21) being programmed to determine at least one maximum wheel cadence value (WCmax) beyond which the pedal cadence control is limited to a predetermined maximum value, called maximum pedal cadence control, said maximum wheel cadence value being determined from the maximum ratio control value and the maximum pedal cadence control.

8. Device according to claim 7, the pedal cadence control comprising a third operating zone, defined for a measured wheel cadence between the second operating point and the maximum wheel cadence value, the means (21) being programmed to calculate a variable pedal cadence command, greater than the pedal cadence calculated during the second operating zone, from at least the constant maximum ratio value.

9. Device according to one of claims 7 or 8, the gearbox ratio control comprising a third operating zone, defined for a measured wheel cadence between the second operating point and the maximum wheel cadence value (WCmax), the means (21) being programmed to calculate a constant gearbox ratio control equal to the maximum gearbox ratio, or variable, from at least the constant maximum ratio value.

10. Device according to claim 8 or 9, the pedal cadence control comprising a fourth operating zone, defined for a measured wheel cadence greater than the maximum wheel cadence value, the means (21) being programmed to calculate a constant pedal cadence control, greater than the variable pedal cadence calculated during the third operating zone, and equal to the maximum pedal cadence control.

11. Device according to one of claims 8 to 10, the gearbox ratio control comprising a fourth operating zone, defined for a measured wheel cadence greater than the maximum wheel cadence value (WCmax), the means (21) being programmed to calculate a constant gearbox ratio control equal to the maximum gearbox ratio, or variable, from at least the constant maximum ratio value.

12. Device according to one of claims 1 to 11, the means (21) being programmed to vary the minimum ratio value of the gearbox (20).

13. Device according to one of claims 1 to 12, the data processing means (21) being programmed to calculate the second operating point as a function, in addition, of a slope, called the slope of the pedal cadence.

14. Device according to one of claims 1 to 13, the data processing means (21) being integrated into the gearbox (20).

15. Device according to one of claims 1 to 14, further comprising: • At least one data collection system (10) for determining at least one rotation speed of the pedal assembly, called

16.

17.

18. pedal cadence instruction; • At least one sensor (30) for measuring the rotation speed of a wheel of the bicycle, called measured wheel cadence. Electrically assisted bicycle comprising an electrically assisted device according to claim 15. Method for controlling the pedaling cadence of an electrically assisted bicycle, the method comprising the steps of: • data collection for receiving in a gearbox (20) information on the rotation speed of the pedal assembly, called the pedal cadence setpoint, and the rotation speed of the bicycle wheel, called the measured wheel cadence, the gearbox (20), comprising a maximum gearbox ratio and a minimum gearbox ratio; • data processing using data processing means (21), integrated into the gearbox (20), making it possible to calculate: • Two wheel cadence values, including: • a smallest wheel cadence value, called the first operating point and determined from at least the value of the minimum gearbox ratio and the pedal cadence setpoint, • a higher wheel cadence value, called the second operating point and determined from at least the maximum gearbox ratio and the pedal cadence setpoint; • at least one pedal rotation speed control, called pedal cadence control. • at least one gearbox ratio control, called gearbox ratio control. Method according to claim 17, the data processing means (21) being programmed to determine at least one maximum wheel cadence value beyond which the pedal cadence control is limited to a predetermined maximum value, called the maximum pedal cadence command, said maximum wheel cadence value being determined from the maximum ratio value and the maximum pedal cadence command.

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