Automatic transmissions and methods therefor
View Patent ↗Systems and methods for controlling transmissions and associated vehicles, machines, equipment, etc., are disclosed. In one case, a transmission control system includes a control unit configured to use a sensed vehicle speed and a commanded, target constant input speed to maintain an input speed substantially constant. The system includes one or more maps that associate a speed ratio of a transmission with a vehicle speed. In one embodiment, one such map associates an encoder position with a vehicle speed. Regarding a specific application, an automatic bicycle transmission shifting system is contemplated. An exemplary automatic bicycle includes a control unit, a shift actuator, various sensors, and a user interface. The control unit is configured to cooperate with a logic module and an actuator controller to control the cadence of a rider. In one embodiment, a memory of, or in communication with, the control unit includes one or more constant cadence maps that associate transmission speed ratios with bicycle speeds.
1. A method of controlling a ball-planetary continuously variable transmission (CVT) on a bicycle comprising a controller, the ball-planetary CVT having a plurality of balls, each ball being rotatable about a tiltable axle, the angle of the axle defining a transmission ratio, the method comprising:
receiving, from a user, an input selecting one of a manual mode and an automatic mode;
if the received input is associated with the manual mode, performing, using the controller, the steps of
receiving an input associated with an increase or a decrease of the transmission ratio, and
communicating a signal to tilt the angle of the axle to increase or decrease the transmission ratio; and
if the received input is associated with the automatic mode, performing, using the controller, the steps of
receiving from the user, an input associated with a target user pedaling speed,
determining, using the controller, a present transmission ratio, and
tilting the angle of the axle to adjust the present transmission ratio of the CVT to a target transmission ratio, wherein the target user pedaling speed is maintained substantially constant over a range of output speeds.
2. The method of claim 1 , wherein tilting the angle of the axle comprises tilting the angle of the axle to maintain a present user pedaling speed within a band of the target user pedaling speed based upon the target user pedaling speed.
3. The method of claim 2 , wherein the band is a range of speeds within 10 revolutions-per-minute (rpm) of the target user pedaling speed.
4. The method of claim 2 , wherein the band is a range of speeds within 5 revolutions-per-minute (rpm) of the target user pedaling speed.
5. The method of claim 1 , further comprising determining an encoder position associated with the target user pedaling speed.
6. The method of claim 5 , further comprising commanding a motor to move to the determined encoder position.
7. The method of claim 1 , wherein adjusting the present transmission ratio of the CVT comprises determining an encoder position associated with the target user pedaling speed and a determined speed of the bicycle.
8. A bicycle having a continuously variable transmission (CVT) having a plurality of tiltable power transmitting balls, each ball being rotatable about a tiltable axle, the angle of the axle defining a transmission ratio, the bicycle comprising:
a processor configured to perform
receiving, from a user, an input selecting one of a manual mode and an automatic mode;
if the received input is associated with the manual mode, performing the steps of
receiving an input associated with an increase or a decrease of the transmission ratio, and
communicating a signal to tilt the angle of the axle to increase or decrease the transmission ratio; and
if the received input is associated with the automatic mode, performing the steps of
receiving, from the user, an input associated with a target user pedaling speed,
determining a present transmission ratio, and
tilting the angle of the axle to adjust the present transmission ratio of the CVT to a target transmission ratio, wherein the target user pedaling speed is maintained substantially constant over a range of output speeds.
9. The bicycle of claim 8 , wherein tilting the angle of the axle comprises tilting the angle of the axle to maintain a present user pedaling speed within a band of the target user pedaling speed based upon the target user pedaling speed.
10. The bicycle of claim 9 , wherein the band is a range of speeds within 10 revolutions-per-minute (rpm) of the target user pedaling speed.
11. The bicycle of claim 9 , wherein the band is a range of speeds within 5 revolutions-per-minute (rpm) of the target user pedaling speed.
12. The bicycle of claim 8 , wherein the processor is configured to determine an encoder position associated with the target user pedaling speed.
13. The bicycle of claim 12 , wherein adjusting the present transmission ratio comprises commanding a motor to move to the determined encoder position.
14. The bicycle of claim 13 , wherein adjusting the present transmission ratio of the CVT comprises determining an encoder position associated with the target user pedaling speed and a determined speed of the bicycle.