System and method for electrically controllable transmissions
Systems and methods are shown for electrically controllably transmitting power from a motor involving electrically controllably coupling the first input hub to a shuttle so that power is transmitted from the first input hub to the shuttle, providing for one-way rotation between the shuttle and a stationary chassis, and coupling the shuttle to an output hub with a spring such that energy is stored and released from the spring as the output hub rotates. Examples are shown that include controlling engaged and disengaged time intervals of the first input hub and shuttle to maintain a torque level at the output hub, such as by utilizing pulse width modulation or pulse frequency modulation. Examples are also shown involving electroadhesively coupling the first input hub to the shuttle.
1. A system, comprising:
an electrically controllable transmission, wherein the electrically controllable transmission comprises a first input hub and a second input hub, a first electrically controllable clutch and a second electrically controllable clutch, a rotatable member, an output hub, and a bias member that couples the rotatable member to the output hub, wherein the first electrically controllable clutch is configured to transmit power between the first input hub and the rotatable member when engaged, and wherein the second electrically controllable clutch is configured to transmit power between the second input hub and the rotatable member when engaged; and
a control circuit configured to apply at least one control signal to at least one electrically controllable clutch of the first and second electrically controllable clutches, wherein the at least one control signal comprises pulses that cause the at least one electrically controllable clutch to engage and disengage in at least one sequence of alternating engagement time intervals and disengagement time intervals, wherein a transmission ratio of the electrically controllable transmission is controlled by the at least one sequence of alternating engagement time intervals and disengagement time intervals.
2. The system of claim 1 , wherein the control circuit is further configured to adjust the transmission ratio of the electrically controllable transmission by adjusting at least one of a width of the pulses or a frequency of the pulses.
3. The system of claim 1 , wherein the at least one control signal comprises pulses that cause the first electrically controllable clutch to engage and disengage in a first sequence of alternating engagement time intervals and disengagement time intervals, wherein the transmission ratio of the electrically controllable transmission is controlled by the first sequence of alternating engagement time intervals and disengagement time intervals.
4. The system of claim 3 , further comprising a one-way clutch that couples the rotatable member to a stationary chassis.
5. The system of claim 3 , wherein the bias member comprises a spring.
6. The system of claim 5 , wherein the spring exchanges energy with the first input hub and the output hub when the first electrically controllable clutch is engaged and exchanges energy with the output hub when the first electrically controllable clutch is disengaged.
7. The system of claim 5 , wherein the spring stores energy by winding and releases energy by unwinding.
8. The system of claim 1 , wherein the first input hub is configured to be driven in a first rotational direction and the second input hub is configured to be driven in a second rotation direction that is opposite the first rotational direction.
9. The system of claim 1 , further comprising:
a first one-way clutch, wherein the first one-way clutch is configured to couple the first input hub to the rotatable member; and
a second one-way clutch, wherein the second one-way clutch is configured to couple the second input hub to the rotatable member.
10. The system of claim 1 , wherein the at least one control signal comprises a first control signal and a second control signal, wherein the first control signal comprises pulses that cause the first electrically controllable clutch to engage and disengage in a first sequence of alternating engagement time intervals and disengagement time intervals and the second control signal comprises pulses that cause the second electrically controllable clutch to engage and disengage in a second sequence of alternating engagement time intervals and disengagement time intervals, and wherein the transmission ratio of the electrically controllable transmission is controlled by the first sequence of alternating engagement time intervals and disengagement time intervals and the second sequence of alternating engagement time intervals.
11. The system of claim 10 , wherein the first electrically controllable clutch is disengaged when the second electrically controllable clutch is engaged, and wherein the second electrically controllable clutch is disengaged when the first electrically controllable clutch is engaged.
12. The system of claim 10 , wherein the bias member comprises a spring.
13. The system of claim 12 , wherein the spring stores energy by winding and releases energy by unwinding.
14. The system of claim 10 , wherein the spring exchanges energy with the first input hub and the output hub when the first electrically controllable clutch is engaged and exchanges energy with the second input hub and the output hub when the second electrically controllable clutch is engaged.
15. The system of claim 1 , wherein the at least one electrically controllable clutch comprises at least one of an electrolaminate disc clutch, an electrolaminate activated wrap spring clutch, or an electromagnetically activated wrap spring clutch.
16. The system of claim 1 , wherein the bias member comprises a torsion spring.
17. The system of claim 1 , wherein the bias member comprises a torsion tube.