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Title:
A HUMAN POWERED ELECTRIC PROPULSION SYSTEM WITH DECOUPLED PEDALS
Document Type and Number:
WIPO Patent Application WO/2019/076438
Kind Code:
A1
Abstract:
The present invention discloses a human powered electric propulsion system, with a pair of pedals (P1, P2) where mechanical torque generated by the user acting on the said pedals (P1, P2) is transmitted to one or more motor-generators (90) mechanically coupled to one or more vehicle wheels. The said pair of pedals (P1, P2) are mechanically decoupled and independently connected to the corresponding motor-generators (10, 20), allowing independent rotation of each pedal (P1, P2) with the variable phase differences in time among the said pedals (P1, P2). The digital signal processing means (40) allows the assisted or resisted pedaling, using the power from or storing the power to the energy storage means (30), that is different for each pedal (P1, P2). Said propulsion system can emulate various terrains and can be also GPS assisted. In one embodiment, one or more such pedaling systems can be combined for propelling one or more wheels vehicles, even by the disabled people.

Inventors:
SERSIC, Damir (Ulica Grada Chicaga 1, Zagreb, HR-10000, HR)
BRKIC, Igor (Antuna Mihanovica 15, Bjelovar, HR-43500, HR)
Application Number:
EP2017/076383
Publication Date:
April 25, 2019
Filing Date:
October 16, 2017
Export Citation:
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Assignee:
SVEUCILISTE U ZAGREBU FAKULTET ELEKTROTEHNIKE I RACUNARSTVA (Unska 3, Zagreb, HR-10000, HR)
International Classes:
B60L11/00
Foreign References:
US7156780B12007-01-02
DE102009032033A12012-02-23
US5125677A1992-06-30
US0552271A1895-12-31
US3884317A1975-05-20
EP0784008B12003-05-07
EP2384923A12011-11-09
Other References:
VAN DER LOOS H.F.; WORTHEN-CHAUDHARI L.; SCHWANDT D.; BEVLY D.M.; KAUTZ S.A.: "A Split-Crank Bicycle Ergometer Uses Servomotors to Provide Programmable Pedal Forces for Studies in Human Biomechanics", IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING, vol. 18, no. 4, August 2010 (2010-08-01), XP011348246, DOI: doi:10.1109/TNSRE.2010.2047586
K. LAMAR: "Digital Control of Permanent Magnet Synchronous Motors", Retrieved from the Internet
J. HOLTZ: "Sensorless control of induction motor drives", PROC. IEEE, vol. 90, no. 8, August 2002 (2002-08-01), XP011065049
R. ASKOUR; B. BOUOULID: "DSP implementation of speed field oriented control of 3-phase permanent magnet synchronous motor", 6EMES JOURNEES D'OPTIQUE ET DE TRAITEMENT DE 1'INFORMATION MOHAMMEDI, 17 April 2008 (2008-04-17)
Attorney, Agent or Firm:
BIHAR, Zeljko (Admoveo d.o.o, Gracanska cesta 111, Zagreb, HR-10040, HR)
Download PDF:
Claims:
CLAIMS

1. A human powered electric propulsion system, with a pair of pedals (11, 21) where mechanical torque generated by the user acting on the said pedals (11, 21) is transmitted, by electric means, to one or more motor-generators (90) mechanically coupled to one or more driving axles, where said propulsion system further comprises :

- motor-generators (10, 20), controlled by controllers (12, 22), mechanically connected with the pair of pedals (11, 21);

- energy storage means (30) which stores, dissipates and releases energy to the said propulsion system;

- one controller (92) for controlling each motor-generator (90);

- a set of sensors distributed on motor-generators (10, 20, 90) for sensing the actual angle and the actual torque of the said motor-generators (10, 20, 90) shafts;

- digital signal processing means (40) capable of recording and storing :

o pedaling modes associated with the torque conversion;

o revolution modes associated with the pedals positions; o driving templates associated with the terrains; and wherein the said digital signal processing means (40) :

a. acquires data from the set of sensors;

b. distributes energy generated by any motor-generator (10, 20, 90) among the propulsion system according to the chosen pedaling mode and actual pedal's revolution mode by using controllers (12, 22, 92) acting on said motors-generators (10, 20, 90);

c. manages storing of the excess system energy into the energy storage means (30), or, manages using of the energy stored into the energy storage means (30) to compensate the system energy deficiency; and

d. electronically emulates continuous mechanical shift gear for converting the mechanical torque generated by the user into desired torque, amplified or attenuated depending on chosen pedaling mode, and exerted on one or more motor- generators (90);

characterized by that:

- the said pair of pedals (11, 21) are mechanically decoupled and independently connected to the corresponding motor-generators (10, 20), allowing independent rotation of each pedal (11, 21) with the variable phase differences in time among the said pedals (11, 21); and

- where digital signal processing means (40) allows transition between assisted or resisted pedaling during the pedal's revolution individually for each pedal (11, 21) and corresponding motor-generator (10, 20) according to the actual revolution mode, where the said revolution mode determines in which part of the actual rotation angle of each pedal (11, 21) corresponding to the motor-generator (10, 20) act as motor or generator .

2. The human powered electric propulsion system according to the claim 1, wherein said digital signal processing means (40) analysis pedal gestures exerted on pedal or pedals to change the human powered electric propulsion system characteristics.

3. The human powered electric propulsion system according to the claim 2, wherein the digital signal processing means (40) uses prestored driving templates to emulate various terrains with different inclinations, thus being suitable for simulating training exercises by affecting the chosen pedaling mode.

4. The human powered electric propulsion system according to the claim 2, wherein the pedaling mode is GPS assisted to fully automate emulated continuous mechanical shift gear according to the actual terrain.

5. The human powered electric propulsion system according to the claims 1-4, wherein the said pair of pedals (11, 21) are synchronized by the digital signal processing means (40) to emulate standard mechanically coupled pedals in its one of the selected revolution modes.

The human powered electric propulsion system according to the claims 1-5, wherein the said energy storage means (30) is exchangeable .

The human powered electric propulsion system according to the claims 1-6, wherein the energy stored in the said energy storage means (30) is exchangeable by an energetic cable between the said electric propulsion systems.

The human powered electric propulsion system according to the claims 1-6, wherein the energy stored in the said energy storage means (30) is exchangeable with the electric grid, by an energetic cable equipped with an electric energy converter.

Use of the human powered electric propulsion system according to any of the claims 1-8, for bicycle power. Use of the human powered electric propulsion system according to any of the claims 1-8, for stationary bike or other exercising devices . Use of the human powered electric propulsion system according to any of the claims 1-8, for transportation, exercising or rehabilitation means for disabled people and reconvalescents suffered from limb injuries. Use of the human powered electric propulsion system according to any of the claim 11, where disabled people are without one or more limbs, or without control of one or more limbs. Use of two or more human powered electric propulsion systems l..n according to any of the claims 1-7 simultaneously in one transportation, exercising or rehabilitation means with the l..k motor-generators (90), wherein each pedal pair (11, 21) uses its own pedaling mode and revolution mode, where total power generated by any motor-generator (10, 20, 90) is managed by the digital signal processing means (40) and energy storage means (30) .

Description:
A HUMAN POWERED ELECTRIC PROPULSION SYSTEM WITH DECOUPLED PEDALS

DESCRIPTION

Technical Field

The present invention discloses a human powered electric propulsion system with decoupled pedals. Therefore, the main technical field to which the present invention belongs may be regarded as the electric propulsion with power supplied within the vehicle; more specifically, where the power is supplied by humans. Some embodiments, disclosed herein, are related to the field of rider propulsion of wheeled vehicles with additional source of power in a form of an auxiliary electric motor. In yet another embodiment the above cited propulsion system is used for helping disabled people to ride the vehicles that are pedals driven.

Technical Problem

The human powered propulsion systems are well known in the art and are used elsewhere; from boats to land vehicles with various number of wheels. The essential technical problem with the human powered propulsion systems is a torque conversion in a manner which prevents quick fatigue of the person that supplies the power to the said vehicle. This technical problem is solved in rider propulsions by using sprocket and chain transmission where it is possible to adjust the transmission rate according to the rider's abilities and needs.

With the development of the electrical motors and batteries, various combinations of electrically assisted human powered vehicles appeared on the market. Such vehicles combine the advantages of light and durable mechanical torque converters and rather simple electrical motor assisted propulsion. The next logical advance in the related art was substitution of the chain and sprocket transmission with the set of motor-generators where the torque is electronically converted by an appropriate signal processing means. Moreover, such solutions offer possibility to store back excess power generated by braking on slopes, to amplify or to attenuate the human power etc.

The next advance in the human powered electric propulsion system is disclosed by the present invention. The present invention is oriented solely to the propulsion systems using pedals; where the pedals can be leg pedals or hand pedals. Observing the motion of the fixed pair of leg or hand pedals where the phase difference among the pedals is 180°, it is evident that some positions offer inefficient torque conversion due to small angle between the applied limb's force vector and radius vector that connects the force vortex with the shaft to which the torque is applied. One possible solution of the observed technical problem is to use the system which is capable to advance the revolution of pedals in time in two specific points when the pedal shafts are substantially parallel with the exerted limb's forces. That action, i.e. advancing one pedal over another, certainly changes the phase difference among the pedals and substantially improves torque conversion bypassing quickly the points where vector product between the applied force and the radius vector is small. To achieve the above said by mechanical means is rather complicated and inefficient. Also, if this problem is solved mechanically, it is solved in a manner that is not easily adjustable.

In contrast to the above, if two motor-generators are used, one for each pedal, it is possible to perform the desired task by simply advancing the pedal revolution in the part of the pedaling cycle when necessary; and that can be simply regulated by an appropriate computer means, e.g. digital signal processing means.

Furthermore, using the decoupled pedals immediately solves other technical problems such as steering and changing the vehicle characteristic with the pedal gestures, pedaling by pumping and enables many other nonconventional ways of riding the human powered vehicles. Decoupled pedals, together with the purely electric torque conversion, may allow the disabled people to use such powered vehicles; for instance, with one pedal riding; or in combination of one hand plus one leg pedaling system.

The present invention is also convenient to be used as an exercising or rehabilitation means for disabled people and reconvalescents suffered from limb injuries having in mind that each pedal revolution can be separately programed in detail.

Previous State of the Art

The US patent no. US 552,271 for the invention "Electrical Bicycle"; inventor 0. Bolton, Jr., discloses very likely the first direct drive electrically powered bicycle.

The US patent no. US 3,884,317 for the invention "Electrically Powered Cycle"; inventor A. B. Kinzel, discloses power operated cycle capable of either front wheel and/or rear wheel drive which eliminates the conventional sprocket and chain mechanical drive. In addition, the said invention provides a switch means or other electrical means to emulate desired transmission between the generator powered by pedals and direct drive motor. Also, this document contemplates about a short circuit means provided for the motor to act as a brake for the cycle.

The EP patent no. EP0784008B1 „Vehicle propelled by muscle-power"; inventors P. Ehrhart et al . , discloses the bicycle that has an electrical generator powered by the cyclist rotating the bicycle pedals, providing the operating current for at least one electric motor used to drive the bicycle. The generator and the electric motor may be coupled to an electronic control, allowing the ratio between the drive torque delivered to the generator and that provided by the motor to be varied continuously or in stages.

The EP patent application no. EP2384923A1 „Asynchronous Wired- Transmission Electric Pedaling Vehicle Driven by Human Generating Power"; inventor Yang, T-H, teaches about an asynchronous wired- transmission electric pedaling vehicle driven by human generating power wherein an electronic transmission is applied.

The above cited prior art mainly demonstrates standard electric bicycle features such as electronically emulated continuous mechanical shift gear for converting the mechanical torque generated by the user into desired torque applied to the driving wheel. The above documents remained silent regarding the other aspects of the disclosed invention such as decoupled pedals features and pedal gestures used to change the human powered electric propulsion system characteristics.

The article written by Van der Loos H.F., Worthen-Chaudhari L., Schwandt D., Bevly D.M., Kautz S.A.: „A Split-Crank Bicycle Ergometer Uses Servomotors to Provide Programmable Pedal Forces for Studies in Human Biomechanics"; IEEE Transactions On Neural Systems And Rehabilitation Engineering, vol. 18, no. 4, August 2010; teaches about a computer-controlled bicycle ergometer, the TiltCycle, for use in human biomechanics studies of locomotion. The TiltCycle has a tilting seat and backboard, a split pedal crankshaft to isolate the left and right loads to the feet of the pedaler, and two belt-driven, computer- controlled motors to provide assistance or resistance loads independently to each crank. Furthermore, the cited work contemplates about decoupled pedaling and subject specific pedaling torque templates for use in human biomechanics studies of locomotion; but not for a human powered propulsion system.

So, it is highly unlikely that the average skilled person in the art would look for the teaching of advanced split-crank bicycle ergometer system in order to improve present human powered electric propulsion system with decoupled pedals. Namely, the present invention uses minimally two different "templates" associated with the final pedaling results; one pedaling modes associated with the torque conversion which allows permanent amplification or attenuation of the torque conversion and is linked with the net energy flow of the system. Another template, or revolution mode, is associated with the pedals positions which determine in which part of the pedaling cycle the pedaling per se should be assisted or resisted. A mutual combination of the said templates yields the final propulsion characteristics used in the vehicle or other devices.

Summary of the Invention

The present invention reveals an improved human powered electric propulsion system. It consists of a pair of pedals where mechanical torque generated by the user acting on the said pedals is transmitted, by electric means, to one or more motor-generators mechanically coupled to one or more vehicle wheels or driving axles. The proposed propulsion system further comprises:

- motor-generators, controlled by controllers, which are mechanically connected with the pair of pedals;

- energy storage means which stores, dissipates and releases energy to the said propulsion system;

- one controller for controlling each motor-generator; and

- a set of sensors distributed on motor-generators for sensing the actual angle and the actual torque of the said motor-generators shafts .

A digital signal processing means is capable of recording and storing: o pedaling modes associated with the torque conversion;

o revolution modes associated with the pedals positions; and o driving templates associated with the terrains.

In addition, the said digital signal processing means:

a. acquires data from the set of sensors;

b . distributes energy generated by any motor-generator among the propulsion system according to the chosen pedaling mode and actual pedal's revolution mode by using controllers acting on said motors- generators ;

c. manages storing of the excess system energy into the energy storage means, or, manages using of the energy stored into the energy storage means to compensate the system energy deficiency, and d . electronically emulates continuous mechanical shift gear for converting the mechanical torque generated by the user into desired torque, amplified or attenuated depending on chosen pedaling mode, and exerted on one or more motor-generators .

The said pair of pedals are mechanically decoupled and independently connected to the corresponding motor-generators. This allows independent rotation of each pedal with the variable phase differences in time among the said pedals. The digital signal processing means allows transition between assisted or resisted pedaling during the pedal's revolution individually for each pedal and corresponding motor-generator according to the selected revolution mode. The said revolution mode determines in which part of the actual rotation angle of each pedal corresponding to the motor-generator act as motor or generator .

In one of embodiments, said digital signal processing means analysis pedal gestures exerted on pedal or pedals in purpose to change the human powered electric propulsion system characteristics.

In yet another embodiment, the digital signal processing means uses prestored driving templates to emulate various terrains with different inclinations, thus being suitable for simulating training exercises by affecting the chosen pedaling mode.

In yet another embodiment, the pedaling mode is GPS (The Global Positioning System) assisted to fully automate emulated continuous mechanical shift gear according to the actual terrain.

In yet another embodiment, the said pair of pedals are synchronized by the digital signal processing means to emulate standard mechanically coupled pedals in its one of the selected revolution modes .

Considering the used energy storage means, it can be exchangeable. Also, the energy stored in the said energy storage means is exchangeable by an energetic cable between different electric propulsion systems. In another variant, the energy stored in the said energy storage means is also exchangeable with the electric grid, by an energetic cable equipped with an electric energy converter.

The above described electric propulsion system can be used for bicycle power, for stationary bike or other exercising devices. In addition, the same electric propulsion system can be used for transportation, exercising or rehabilitation means for disabled people and reconvalescents suffered from limb injuries; more specifically, where disabled people are without one or more limbs, or without control of one or more limbs.

In the most general case, it is possible to use two or more human powered electric propulsion systems numbered l..n simultaneously in one transportation, exercising or rehabilitation means with the l..k motor-generators. In that case each pedal pair uses its own pedaling mode and revolution mode. The total power generated by any motor- generator is managed by the digital signal processing means and corresponding energy storage means .

Brief Description of Drawings

Fig. 1 shows the basic scheme of human powered electric propulsion system according the invention. Fig. 2 shows the system presented on the Fig. 1 applied to an electric bicycle. Fig. 3 shows the way the pedals being mechanically decoupled and independently connected to the corresponding motor-generators .

Fig. 4A depicts the situation where the pedals have a phase difference (180° - δ) . Fig. 4B shows absolute pedals' angles (φι, Φ2) corresponding to the pedals (11, 21) and measured from the z-axis. Fig. 4C shows (|)i(t) and Φ2 (t) vs. time in case of asynchronous pedaling.

Fig. 5 depicts the situation where two or more human powered electric propulsion systems numbered l..n are used simultaneously in one transportation, exercising or rehabilitation means with the l..k motor-generators .

Fig. 6 shows the block scheme of controllers for controlling motor- generators, Fig. 7 depicts one of possible ©-estimators used for calculation angular velocities and accelerations of the motor- generators shafts.

Figs. 8A-8F depict examples of pedal gestures exerted on pedal or pedals in purpose to change the human powered electric propulsion system characteristics.

Detailed Description

The present invention discloses human powered electric propulsion system with decoupled pedals, where "pedals" stands for leg and/or hand pedals equally, without restrictions.

In its essential form, the human powered electric propulsion system consists of a pair of mechanically decoupled pedals (11, 21) adapted to be used by a pair of limbs. Each pedal (11, 21) is connected independently with its motor-generator (10, 20) . It is convenient to use 3-phase permanent magnet synchronous (PMSM) motor-generators for the energy intake, i.e. for converting mechanical energy produced by the user into the electrical energy, having in mind recent developments of such motor-generators. Each motor-generator (10, 20) is controlled by the corresponding controller (12, 22), which will be discussed in detail later.

The electric power generated by the pedal motor-generators (10, 20) is transmitted to the motor-generator (90), controlled by the controller (92) and mechanically coupled to one or more vehicle wheels or driving axles. Again, it is convenient to use 3-phase permanent magnet synchronous (PMSM) motor-generator (90) due to its torque control abilities. During standard operation, the motor-generators (10, 20) dominantly work in a generator regime and the motor generator (90) works in a motor regime. The physical realities, i.e. the user limbs on one side of the propulsion system and the driving axle(s) on another side, are connected in an electric manner that allows manipulation with the said physical reality.

For the manipulation with the physical reality it is essential that the system contains an energy storage means (30) . Role of the energy storage means (30) is to store, dissipate and release energy to the said propulsion system according to the user needs. The most convenient energy storage means (30) is a standard lithium-ion battery pack that can be equipped with a battery management system and a resistor as an ohmic dissipating element. Other energy storage means (30) with acceptable volume energy and power density can be equally used, as already known in the art. The role of the dissipating element is to convert excess energy generated into the propulsion system to heat, in case the storage element cannot store the excess energy. This situation may occur when the battery is full, after charging from the electric grid or during a long-term downhill drive with the vehicle equipped with the propulsion system according to the said invention. In addition, the dissipating element can also serve as an electric brake in a manner that is well known in the art.

Each of the said motor-generators (10, 20, 90) has to be equipped with a set of sensors for sensing the actual angle and the actual torque of the said motor-generators (10, 20, 90) shafts. The "set of sensors", as used hereby means any physical sensor known in the art such as angle resolver or incremental encoder, or Hall effect based angle sensors; or piezoelectric force sensors, or force sensing resistors, or strain gauges. However, the algorithm that is capable to estimate the above said values; i.e. shaft's angle and torque, from the operational characteristics of the (PMSM) motor-generators (10, 20, 90) can be equally used. Examples of such algorithms are described in following articles:

K. Lamar: "Digital Control of Permanent Magnet Synchronous Motors"; http : / /uni-obuda . hu/ conferences/ jubilee/Lamar . pdf J. Holtz : "Sensorless control of induction motor drives," in: Proc. IEEE, Volume: 90, Issue: 8, Aug 2002.

Considering the drawbacks of the above described solution; and the use of other motor-generators (10, 20, 90) than PMSP, the standard reliable sensorics system is very likely to be applied due to the cost-effectiveness of said solution. The sensors are connected to the corresponding controllers (12, 22, 92) that controls motor-generators (10, 20, 90) and the data obtained by said sensors are also available to the digital signal processing means (40) via controllers (12, 22, 92) .

The digital signal processing means (40) logically connects two before mentioned physical realities and renders the entire system possible. In its simplest form, it can be any computing device suitable to be connected to the corresponding controllers (12, 22, 92) and energy storage means (30) . In practice, any ARM processor based computing device with appropriate memory is sufficient for performing that task. The mechanical connection, that is emulated by the said propulsion system, between user' s limbs and the driving axles can be equal to the reality with all dissipation generated by the system per se, or can be distorted according to the user's needs. In the following invention three types of reality adjustments can be imposed to the system .

The first adjustment of the propulsion system is made by selecting the pedaling mode. The pedaling mode relates to the overall energy balance of the propulsion system. The pedaling mode can be neutral; the whole energy generated by the user is transmitted to the driving axles. However, the chosen pedaling mode can be used to amplify or to attenuate mechanical torque produced by the user for some multiplication factor, e.g. x2 or x0.5, that is exerted on one or more driving axles. The digital signal processing means (40) compensates any energy disbalance resulting from the above by the energy storage means (30) . Therefore, the pedaling mode is constant over many pedals revolutions and such solution is well known in the prior art.

The second adjustment of the propulsion system is made by selecting the revolution mode. The revolution mode is associated with the pedals positions only. The digital signal processing means (40) allows transition between assisted or resisted pedaling during the pedal's revolution individually for each pedal (11, 21) that is mechanically connected to the corresponding motor-generator (10, 20) . The selected revolution mode determines in which part of the actual rotation angle of each pedal (11, 21) corresponding motor-generator (10, 20) act as motor or generator.

Evidently the actual state of any motor-generator (10, 20) affect the total energy balance of the said propulsion system. Any energy deficiency has to be compensated by the energy storage means (30) . It is worth to note that the revolution mode, i.e. when the pedals move independently during the pedaling with immediate transition between assisted or resisted pedaling during the pedal's revolution, make possible to solve the prior observed technical problems. Also, the selected revolution mode therefore enables even disabled people without one or more limbs, or without control of one or more limbs - to use the said propulsion system.

The pedaling graph presented on Fig. 4C shows independent revolution of pedals (11, 21) measured from the z-axis, as depicted on Fig. 4B, in the form of their respective angles φι (t) and $2(t) . The difference defined as 5(t) = §2{t) - c|)i(t) - 180°, which is time dependent, indicates that the pedals are being decoupled in accordance with previously selected revolution mode.

In some other embodiments, the third adjustment of the propulsion system is made by selecting appropriate driving template. The driving template, as used by this invention, comprises: terrain configurations, exercising templates, or any other template by which is possible to further affect the pedaling mode by making pedaling more or less difficult due to the imposed environment or other physical variables and user's needs.

Skilled person in the art will immediately recognize the fact the that all three modes, i.e. pedaling modes, revolution modes and driving templates can be stored and/or recorded by the propulsion system, more particularly by the digital signal processing means (40) as a part of it, which will be discussed in detail later.

In its simplest way of the operation, the digital signal processing means (40) distributes energy generated by any motor-generator (10, 20, 90) among the propulsion system according to the chosen pedaling mode and actual pedal's revolution mode by using controllers (12, 22, 92) acting on said motors-generators (10, 20, 90) . Also, it manages storing of the excess system energy into the energy storage means (30) , or, manages using of the energy stored into the energy storage means (30) to compensate the system energy deficiency due to the selected pedaling mode and actual pedal's revolution mode.

It is well-known in the art that such human powered electric propulsion system electronically emulates continuous mechanical shift gear for converting the mechanical torque generated by the user into desired torque, amplified or attenuated, depending on chosen pedaling mode, and exerted on one or more motor-generators (90) .

One of possible solutions for efficient control of the system consisting of three motor-generators (10, 20, 90) is depicted in Fig. 6. The goal of this control system is to produce desired torque with minimum reactive power generated within the system. The J q signal represents quadrature current component that is proportional with the torque. The transition between the generator or motor mode is obtained by changing the polarity of the said signal. The flux Jd signal is usually set to zero except in cases where it is necessary to weaken the magnetic field in order to obtain a higher maximum motor speed, but with reduced torque. The signals, namely Id-id and I q -i q , picked and processed by the proportional-integral regulators (PI regulators) to produce quadrature voltage components Vd and V qr are transformed via the inverse Park transformation to create rotating voltage components V a and V, to which the inverse Clarke transformation and appropriate PWM (pulse-width-modulator) is applied to produce 3-phase voltages V a , ¾ and V c , in purpose to control PI, P2 and Ml motor- generators by the 3-phase inverter, wherein PI and P2 are motor- generators connected to the pedals, and Ml is motor-generator connected to the driving axle. In Fig. 6 motors and generators PI, P2 and Ml are annotated as PMSM (10) . The necessary power is released or stored into the energy storage means which is not shown.

The J-estimators are used to estimate the I vectors based on two or three current sensors distributed on each motor-generator. Estimated 3-phase data i a , it and i c is further processed by the Clarke transformation to produce rotating current components ί α and ίβ, and the Park transformation in order to generate reference quadrature signals id and i g , used for field oriented vector control of three- phase inverters; to which desired torque J q and flux Jd signals are compared .

Realization of before mentioned Park and inverse Park transformation needs an adequate estimator of rotor flux angle Θ. It can be measured directly or indirectly, the latter often using I vectors. A possible Θ-estimator is depicted in Fig. 7, wherein the Kalman estimator is used to derive all necessary angular values of each motor-generator, such as angular velocity Θ' (t) and angular acceleration Θ" (t) , beside the before mentioned actual angle Θ. Kalman estimator is an algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone, by using Bayesian inference and estimating a joint probability distribution over the variables for each time frame .

Similar way of controlling motor-generators can be found in the prior art everywhere, the good example is the article : R. Askour and B. Bououlid: "DSP implementation of speed field oriented control of 3- phase permanent magnet synchronous motor", 6emes Journees d'Optique et de Traitement de 1 ' Information Mohammedi a les 17 & 18 avril 2008; that is possible to obtain here: https : // w . researchgate . net/publication/ 273318616

It is important to note that the described efficient controlling of the system which consists of three motor-generators (10, 20, 90) can be formed on various ways disclosed in prior art. However, it is important to achieve a reliable conversion of torques produced on motor-generators (10, 20) to be transformed to the power for the motor-generator (90) which exerts torque on the driving axle. For that task, a non-linear function is used to connect these two physically separated worlds - user's limbs and driving axles of the said propulsion system according to the output power / torque needs in desired pedaling phase.

The invention is described in the examples below. Before going through examples, the skilled person in the art will recognize the fact that the pedals used for legs/feet should exert some counter-torque to the feet, usually in a direction opposite to the ground, to be able to sense any torque change exerted by the user's feet; or foot absence if necessary.

Example 1 - Asynchronous pedaling

In its simplest form, the human powered electric propulsion system according to the invention can be applied to the bicycle, as depicted in Figs. 2-4A, 4B 4C. Difference to the prior-art solution is that the decoupled pedals (11, 21) enable the difference 5(t) from 180° standard phase difference among the pedals in the way that the digital signal processing means (40) advances right motor-generator (10), by using solely motor option, for the angle δ when the pedal (11) is close to the uppermost revolution point. Then, the motor-generator (10) advances the pedal (11) into such position to maximize the exerted torque by the right foot, as depicted in Fig. 4C. The similar approach is also useful for the hand pedals for maximizing the efficiency of the propulsion system.

The skilled person in the art will immediately recognize other possibilities, i.e. other revolution modes that can be applied to maximize the torque produced by all user's limbs. The human powered electric propulsion system according to the invention overperforms potential competitive mechanical solutions since the difference δ (t) is fully software controlled.

Example 2 - Riding by pumping or rowing

The present invention enables completely unconventional riding a bicycle by pumping. The digital signal processing means (40) can "glue" the pedals together without 0° phase difference δ among the pedals. By siting, the user can press both pedals downwards to generate the energy to the propulsion system, and the signal processing means (40) will bring the pedals reversely back to the position when again the user is capable to push it simultaneously downwards, like pushing the springboards downwards .

Pumping can be applied to the hand pedals, also. In that case convenient way to generate energy can be either pulling, or pushing, or both. Pulling of hand pedals, or handles, can be regarded as rowing. Alternatively, pedals can move in opposite direction, which means phase difference is oscillating synchronously with the limb movement, to realize stepper like behavior of foot pedals, or alternating paddling effect of hand pedals.

Example 3 - Reverse pedaling

For some medical indications during the limb injuries rehabilitation it is recommended for the patients to use reverse pedaling. The reverse pedaling, if such pedaling mode and corresponding revolution mode is chosen, can have a total effect to the vehicle to be propelled forwardly while the user performs the reverse pedaling.

Example 4 - Pedal Gestures

The digital signal processing means (40) is capable to perform analysis of the pedal gestures exerted on pedal or pedals to change the human powered electric propulsion system characteristics. As mentioned before, used controllers CP1 and CP2, Fig. 1, associated with the corresponding pedals are capable to estimate the exerted torque on the pedals. If programed in that sense, the digital signal processing means (40) can interpret applied torque in the specific part of pedals' revolution as the gesture for changing current propulsion system characteristics.

A good example for such gesture may be sudden reverse pedaling which may be interpreted as the coaster brake, i.e. back pedaling brake.

Another example can be a series of two or more pulses / strokes exerted on one pedal in predefined timeframe that may be interpreted as a command for more assistance, Fig. 8B, or less assistance, Fig. 8C, depending on which pedal was exerted: the one that corresponds to the direction of the vehicle movement, or the opposite one.

Another example is two strokes exerted on both pedals simultaneously, i.e. Fig. 8D, which may be interpreted as a transition from human propelled pedaling mode to fully electrically propelled mode, when all the power comes from the energy storage means (30) . Fig. 8F depicts an opposite gesture that may be interpreted as a transition from fully electrically propelled mode back to the common pedaling mode.

The skilled person in the art will immediately recognize other possibilities to change the propulsion system characteristics by applying various predefined gestures. Also, the user can record own set of the gestures to the digital signal processing means (40) and address particular action with the recorded gesture. Set of the possible gestures are depicted on the Figs. 8A-8F;

8A: gesture for "go forward" or "accelerate",

8B: gesture for "more assistance",

8C: gesture for "less assistance",

8D: gesture for "go full electric",

8E: gesture for "start pumping",

8F: gesture for "start pedaling",

where solid arrows denote the exerted pressure / command on pedals; vehicle direction is depicted with the wide arrow and dashed arrow represents current pedal motion. The choice of available gestures, as well as its meaning, depends on the current revolution and pedaling modes .

Example 5 - Terrain simulations

Due to the bad weather conditions, i.e. snow, or other reasons sometimes it is not convenient to perform training in real environment. The present invention enables using of driving templates, previously recorded or stored to the digital signal processing means (40), to emulate various terrains with different inclinations. Such driving template affects the chosen pedaling mode and therefore the corresponding energy balance of the propulsion system, as discussed earlier. The net effect for the user is that the user feels pedaling more or less difficult even when performed on perfectly flat terrain, such is possible to find into sport arenas.

In another variant, the bicycle can be exchanged by a stationary bike or other similar exercising devices where the terrains can be added in an exercising scheme by applying said propulsion system and driving templates .

Example 6 - the GPS assisted automatic shift gear

Beside the already listed features that can be applied to the said human powered electric propulsion system with decoupled pedals, it is possible to include position-related features. As discussed earlier, the digital processing means (40) electronically emulates continuous mechanical shift gear for converting the mechanical torque generated by the user into desired torque.

The torque conversion ratio can be fully automated in a manner that is GPS assisted together with the maps containing elevation profiles. Such elevation profiles can be recalculated from standard GPS data, as shown here: http://www.gpsvisualizer.com/profile input. So, on more inclined terrains the transmission ratio can be preset to the lowest gears, i.e. with more pedal revolutions for one driving axle revolution, according to the GPS data obtained from the GPS receiver built in the digital signal processing means (40), or via an external GPS device.

Example 7 - standard 180° pedal phase shift

According to the invention, the pedals are entirely mechanically decoupled. In one embodiment, the pedals can be electronically coupled to obtain standard 180° pedal phase shift, so the user will be able to use also this special pedal's revolution mode, if desired. All other features of the said propulsion system can be combined with this feature .

Example 8 - starting position for pedals

It is known in the art that the bicycle leg pedaling requires specific pedaling position for starting. It is possible to program the digital signal processing means (40) to set the pedals into starting position whenever the bicycle stops; or in a case of exercising means, before each set of exercises.

Example 9 - other usages of the described propulsion system

It is immediately evident that the human powered electric propulsion system with decoupled pedals can be used in its stationary form as a stationary bike or other exercising device having in mind that "pedals" may refer to leg and/or hand pedals.

In these variants, the driving axle output should be subjected to a mechanical load (rollers, friction wheels, ...) or electrical load (generators, electric grid, energy storage, ...) , to accept the energy generated by the user. However, the ways of controlling the propulsion system remains the same; pedaling modes and revolution modes can be equally used; while the "driving templates" can be exchanged by the "exercising templates".

In some other variants, the human powered electric propulsion system with decoupled pedals can be used also in transportation, exercising or rehabilitation means for disabled people and reconvalescents suffered from limb injuries. At this point it is necessary to emphasize that the different revolution modes, according to the invention, are applied for each limb/pedal and that fact would certainly help disabled people to ride a bike, or other pedaling devices as ordinary people do.

It should be noted that the appropriately programed revolution modes enable the disabled people; which are without one or more limbs, or without control of one or more limbs; to ride the pedaling vehicles, or to use various pedaling exercising devices without the need to be specifically tailored for them. That is one of the major advantages of the said propulsion system, which needs only software adjustments in the form of revolution modes that are applicable to all user's categories. Rehabilitation templates combined with specific revolution modes can, for instance, split the pedaling power asymmetrically between the limbs pair, to increase pedaling assistance on more injured or disabled limb.

Example 10 - combinations of described propulsion system

For the person skilled in the art is evident that two or more such propulsion system can be applied to one vehicle, more particularly to one transportation, exercising or rehabilitation means. Such principal scheme is disclosed on Fig. 5 where l..n propulsion systems are combined together to drive l..k motor-generators (90) . The pedaling pairs parts, denoted as (PI, P2), (P3, P4), ... (P2n, P(2n-1)) can be hand or foot pedal's motor-generators. In practice, there will be one or two motor generators (90) used for driving axles.

Again, the important feature is that each pedal pair (11, 21) uses its own revolution mode and pedaling mode. The total power generated by any motor-generator (10, 20, 90) is managed by the digital signal processing means (40) and energy storage means (30) and affected by the driving template performed for the vehicle, if necessary.

Example 11 - the energy storage means features

It is well known that in a group pedaling, e.g. when the propulsion system is used for bicycle, different physical abilities are very common. Children are usually physically inferior to their parents and this can be simply compensated by the appropriate pedaling modes. Namely, the children can amplify the torque conversion to be equally "strong" as their parents are. The drawback of this solution is that the energy storage means (30) will be emptier in the children's case considering that the storage means is used for compensation of the power deficiency within the propulsion system. On the other hand, the parent's energy storage means (30) will be almost full of disposable energy. So, it is important then the energy storage means (30) is easily exchangeable, i.e. swappable. On that basis, one user can supply the electric power for another user for entire pedaling trip.

The different producers of the described propulsion system will certainly form geometrically different energy storage means (30) that are not easily swappable among each other. So, in some other variants, the energy stored in the said energy storage means (30) should be exchangeable by an energetic cable between the said electric propulsion systems in order to perform quick charging/discharging in a way that is well known in the art and widely adopted for electric cars .

In some other variants of the invention, the energy stored in the said energy storage means (30) have to be exchangeable even with the electric grid, by an energetic cable equipped with an electric energy converter. Such variant enables the exercising power to be used for lighting or cooling purposes somewhere if necessary; or, more likely to be used for quick charging from the electrical grid.

Industrial Applicability

The present invention discloses a novel human powered electric propulsion system with decoupled pedals. Therefore, the industrial applicability is evident.

References and abbreviations

10 - motor-generator [PI]

11 - right pedal

12 - controller [CP1]

20 - motor-generator [P2]

21 - left pedal

22 - controller [CP2]

30 - energy storage means [ES]

40 - digital signal processing means

90 - motor-generator [Ml]

92 - controller [CM1]

PI - proportional-integral regulators

PWM - pulse-width-modulator

PMSM - permanent magnet synchronous motor-generators