Control system for continuously variable transmission
First Claim
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1. A control system for a continuously variable transmission for a vehicle having an engine wherein a reduction ratio is determined in response to an operating position of a shift actuator that is operable on a shift command signal, comprising:
- means for producing a feed-forward control value indicative signal representative of a target operating position of the shift actuator;
means for producing a target value indicative signal representative of a target operating position of the shift actuator;
means for producing a feed-back value which is variable in response to a change in the operating position of the shift actuator and generating a feed-back value indicative signal;
means for determining a feed-back control value as a function of a difference between said target value indicative signal and said feed-back value indicative signal;
means for deciding whether feed-forward control or feed-back control is to be executed based on said difference between said target value indicative signal and said feed-back value indicative signal; and
means for supplying said feed-back control value indicative signal, as a shift command signal, to the shift actuator when said deciding means decides that the feed-back control is to be executed, and supplying said feed-forward control value indicative signal, as the shift command signal, to the shift actuator when said deciding means decides that the feed-forward control is to be executed.
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Abstract
A control system for a continuously variable transmission wherein when a difference between an actual value and a target value is greater than a predetermined value, a feed-forward control is used, whereas when the difference is smaller than the predetermined value, a feed-back control is used.
32 Citations
14 Claims
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1. A control system for a continuously variable transmission for a vehicle having an engine wherein a reduction ratio is determined in response to an operating position of a shift actuator that is operable on a shift command signal, comprising:
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means for producing a feed-forward control value indicative signal representative of a target operating position of the shift actuator; means for producing a target value indicative signal representative of a target operating position of the shift actuator; means for producing a feed-back value which is variable in response to a change in the operating position of the shift actuator and generating a feed-back value indicative signal; means for determining a feed-back control value as a function of a difference between said target value indicative signal and said feed-back value indicative signal; means for deciding whether feed-forward control or feed-back control is to be executed based on said difference between said target value indicative signal and said feed-back value indicative signal; and means for supplying said feed-back control value indicative signal, as a shift command signal, to the shift actuator when said deciding means decides that the feed-back control is to be executed, and supplying said feed-forward control value indicative signal, as the shift command signal, to the shift actuator when said deciding means decides that the feed-forward control is to be executed. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A control system for a continuously variable transmission for a vehicle wherein a reduction ratio is determined in response to an operating position of a shift actuator that is operable on a shift command signal, comprising:
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means for producing a feed-forward control value indicative signal representative of a target operating position of said shift actuator; means for producing a target value indicative signal representative of a target operating position of the shift actuator; means for detecting a feed-back value which is variable in response to a change in operating position of the shift actuator and generating a feed-back value indicative signal; means for determining a feed-back control value as a function of a difference between said target value indicative signal and said feed-back value indicative signal; means for adding said feed-forward control value indicative signal to said feed-back control value indicative signal and generating a summation indicative signal; means for deciding whether feed-forward control or feed-back control is to be executed based on said difference between said target value indicative signal and said feed-back value indicative signal; and means for supplying said summation indicative signal, as the shift command signal, to the shift actuator when said deciding means decides that the feed-back control is to be executed, and supplying said feed-forward control value indicative signal, as the shift command signal, to the shift actuator when said deciding means decides that the feed-forward control is to be executed. - View Dependent Claims (9)
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10. In a control, system for a continuously variable transmission for a vehicle, the control system having a target value variable with a target reduction ratio determined based on various input signals representative of an operating state of the vehicle, a shift actuator operable in response to a shift command signal to cause a shift in reduction ratio of the continuously variable transmission, a feed-back value variable with the actual reduction ratio;
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means for comparing the feed-back value with the target value and producing a difference therebetween; means for supplying a feed-forward signal as said shift command signal in order to effect a feed-forward control of the shift actuator to cause a shift in reduction ratio thus reducing said difference towards zero when said difference is greater than a predetermined value; and means for supplying a signal indicative of said difference as said shift command signal in order to effect a feed-back control of the shift actuator to cause a shift in reduction ratio thus reducing said difference toward zero when said difference is at or less than predetermined value. - View Dependent Claims (11, 12, 13, 14)
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Specification