Shifting system for human-powered vehicle

1. A shifting system for a human-powered vehicle, comprising:

a controller configured to:

receive a driving torque and a cadence of the human-powered vehicle from at least one sensor;

determine a permitted shift timing based on the driving torque and the cadence; and

control a shift mechanism to perform a gear shift during the permitted shift timing.

2. The shifting system according to claim 1 , wherein

the controller is configured to output a command signal for the gear shift to the shift mechanism if a current timing is in the permitted shift timing.

3. The shifting system according to claim 2 , wherein

the controller is configured to refrain from outputting the command signal to the shift mechanism if the current timing is outside the permitted shift timing.

4. The shifting system according to claim 1 , wherein

the permitted shift timing includes a first timing interval that has a first start and a first end, and

the controller is configured to output a command signal for the gear shift to the shift mechanism if a current timing is between the first start and the first end of the first timing interval.

5. The shifting system according to claim 4 , wherein

the first start of the first timing interval is a timing at which the driving torque is detected to reach a first threshold as the driving torque is rising in a pedaling cycle.

6. The shifting system according to claim 5 , wherein

the first end of the first timing interval is a timing at which the driving torque is detected to reach a second threshold as the driving torque is rising in the pedaling cycle, and

the second threshold is greater than the first threshold.

7. The shifting system according to claim 4 , wherein

the permitted shift timing includes a second timing interval that has a second start and a second end, and

the controller is configured to control the shift mechanism to perform the gear shift by outputting the command signal for the gear shift to the shift mechanism if the current timing is between the second start and the second end of the second timing interval.

8. The shifting system according to claim 7 , wherein

the second start of the second timing interval is a timing at which the driving torque is detected to reach the second threshold as the driving torque is falling in the pedaling cycle.

9. The shifting system according to claim 8 , wherein

the second end of the second timing interval is a timing at which the driving torque is detected to reach the first threshold as the driving torque is falling in the pedaling cycle.

10. The shifting system according to claim 2 , wherein the controller is configured to:

receive an input regarding the gear shift; and

temporarily hold the command signal in a memory of the controller until the permitted shift timing is reached if the input is received at an input timing that is outside the permitted shift timing.

11. The shifting system according to claim 10 , wherein

the controller is configured to output a preliminary signal to the shift mechanism to perform a preparation for the gear shift before outputting the command signal temporarily held in the memory.

12. The shifting system according to claim 1 , wherein

the permitted shift timing includes a first timing interval that has a first start and a first end, and

the controller is configured to control the shift mechanism to perform the gear shift by:

determining at least one of an estimated travel distance of the shift mechanism and estimated travel speed of the shift mechanism for performing the gear shift;

calculating an estimated duration of time that is required for performing the gear shift based on at least one of the estimated travel distance and the estimated travel speed;

determining that the gear shift can be commenced after the first start of the first timing interval and completed prior to the first end of the first timing interval; and

outputting the command signal to the shift mechanism based on the determination result.

13. The shifting system according to claim 12 , wherein

the estimated travel speed is calculated based on the cadence and the travel distance.

14. The shifting system according to claim 12 , wherein

the gear shift is one of a plurality of gear shifts, the estimated travel distance is one of a plurality of estimated travel distances, and the estimated travel speed is one of a plurality of estimated travel speeds, and

the controller is configured to:

store a map that maps each of the plurality of gear shifts to an associated one of the plurality of estimated travel distances and one of the plurality of estimated travel speeds in a memory, and

determine the at least one of the estimated travel distance and the estimated travel speed for performing the gear shift at least in part by using the map to identify at least one of the estimated travel distance and the estimated travel speed associated with the gear shift.

15. The shifting system according to claim 12 , further comprising:

the shift mechanism including a rear derailleur having a rear chain guide configured for lateral movement over the estimated travel distance in a direction parallel to a rotational axis of a rear sprocket assembly having a plurality of rear sprockets to urge a chain from the one of the rear sprockets to the other of the rear sprockets in the gear shift.

16. The shifting system according to claim 12 , further comprising:

the shift mechanism including a front derailleur having a front chain guide configured for lateral movement over the estimated travel distance in a direction parallel to a rotational axis of a front sprocket assembly having a plurality of front sprockets to urge a chain from the one of the front sprockets to the other of the front sprockets in the gear shift.

17. The shifting system according to claim 1 , further comprising:

an indication device, wherein

the controller is configured to cause the indication device to indicate the permitted shift timing by at least one of a visual manner, an aural manner, and a haptic manner.

18. The shifting system according to claim 1 , further comprising:

a manual input device, the controller being configured to receive a shift input requesting the gear shift via the manual input device.