Patent EA-004382-B1 (EA)
Title: A system and a method for the control of variable-ratio transmissions
Inventor: FERRERO PIETRO
IPC: B62M25/08
Filed: 2000-08-21
Abstract: 1. A system for controlling a variable-ratio transmission mounted on an transport means, the transmission being associated with an actuator for changing the transmission ratio, and operating means for applying an input driving force to the transmission by a periodic action of given frequency, the system comprising first sensor means which are sensitive to the driving force, for generation of the first signal, second sensor means which are sensitive to the speed of operation of the transport means, for generation of second signal, and a control means controlling the actuator in dependence on the first signal and the second signal, and the system being characterized in that it contains third sensor means which are sensitive to the frequency of applying an input driving force for generation of the third signal, the control means being configured to determine, from at least the first signal and the second signal, a reference signal indicative of a reference value for the frequency with the following comparing with the third signal forming a derivation signal, and with the possibility of acting on the actuator, changing the transmission ratio so as to minimize the deviation signal. 2. A system according to Claim 1, characterized in that the first sensor means comprises a device for measuring the pedaling force applied to a pedal crank of a bicycle, the second sensor means comprises a sensor for detecting the forward speed of the bicycle, and the control means is a control means which can act on at least one gearbox mounted on the bicycle. 3. A system according to Claim 1 or Claim 2, characterized in that the control means is configured so as to determine the frequency reference signal also in dependence on the third signal. 4. A system according to any one of claims 1-3, characterized in that the control means comprises a first functional module sensitive to the first signal and can classify the first signal in dependence on a respective first degree of affinity, a second functional module which is sensitive to the second signal and can classify the second signal in dependence on a respective second degree of affinity, a third functional module for the application of rules, which is sensitive to respective values of the first and second degrees of affinity and can determine the frequency reference value with values differentiated in dependence on the values of the first and second degrees of affinity. 5. A system according to Claim 4, characterized in that it comprises at least one control module operable selectively in order to vary selectively at least one of the criterion for the attribution of the first degree of affinity by the first functional module, the criterion for the attribution of the second degree of affinity by the second functional module, and the law for the determination of the frequency reference value by the third functional module from the degrees of affinity attributed by the first functional module and the second functional module and the first and second signals. 6. A system according to Claim 4 or Claim 5, characterized in that the first, the second and the third functional modules operate in accordance with a fuzzy logic. 7. A system according to Claim 5, characterized in that the control module comprises at least one of next elements: a first functional control module (8) for selectively varying the criterion for the attribution of the first and second degrees of affinity by the first and second functional modules in dependence on the cyclist's athletic level, a second functional control module for selectively varying the criterion for the attribution of the first and second degrees of affinity by the first and second functional modules in dependence on various strategies for the riding of the bicycle (1), and a third functional control module for selectively varying the rules for determining the frequency reference value given by the third functional module. 8. A system according to any one of claims 1-7, characterized in that the control means includes a function for inhibiting action on the actuator for a period of time of predetermined duration starting from the preceding action performed by the control means on the actuator in order to change the transmission ratio. 9. A system according to Claim 8, characterized in that the duration of the time interval is variable selectively. 10. A method of controlling a variable-ratio transmission mounted on an transport means, the transmission being associated with an actuator for changing the transmission ratio, and operating means for applying an input driving force to the transmission by a periodic action of given frequency, the method comprising the steps of: - detecting the driving force and generating a respective first signal, - detecting the speed of operation of the transport means and generating a respective second signal, and - controlling the second actuator in dependence on the first and second signals, and being characterized in that it comprises the steps of: - detecting the given frequency and generating a respective third signal, - determining, from at least the first signal and the second signal, a reference signal indicative of a reference value for the frequency, - comparing the reference signal and the third signal so as to identify a corresponding deviation signal, and - controlling the actuator, changing the transmission ratio so as to minimize the deviation signal. 11. A method according to Claim 10, characterized in that it comprises the steps of: - generating the first signal as a signal indicative of the pedaling force applied to a pedal crank of a bicycle, - generating the second signal as a signal indicative of the forward speed of the bicycle itself, and - controlling, as the actuator, at least one gearbox mounted on the bicycle. 12. A method according to Claim 10 or Claim 11, characterized in that it comprises the step of determining the frequency reference value also in dependence on the third signal. 13. A method according to any one of Claims 10 to 12, characterized in that it comprises the steps of: - classifying the first signal in dependence on a respective first degree of affinity, - classifying the second signal in dependence on a respective second degree of affinity, and - determining the frequency reference value with values differentiated in dependence on the values of the first and second degrees of affinity. 14. A method according to Claim 13, characterized in that it comprises the steps of selectively varying at least one of the criterion for the attribution of the first degree of affinity, the criterion for the attribution of the second degree of affinity, and the law for the determination of the frequency reference value from the degrees of affinity attributed to the first and second signals. 15. A method according to Claim 13 or Claim 14, characterized in that the attribution criteria and the determination laws are based on a fuzzy logic. 16. A method according to Claim 11 and Claim 14, characterized in that it comprises at least one of the steps of: - selectively varying the criterion for the attribution of the first and second degrees of affinity in dependence on the cyclist's athletic level, - selectively varying the criterion for the attribution of the first and second degrees of affinity in dependence on various strategies for the riding of the bicycle, and - selectively varying the rules for the determination of the frequency reference value from the degrees of affinity. 17. A method according to any one of preceding Claims 10 to 16, characterized in that it comprises the step of inhibiting action on the actuator for a period of time of predetermined duration starting from the preceding action performed on the actuator in order to change the transmission ratio. 18. A method according to Claim 17, characterized in that the duration of the period of time is variable selectively.