US 2002/0161503 A1Published application

Enhanced ratio control in a toroidal drive

AssigneeNissan Motor Co., Ltd.

InventorsShinichiro Joe, Taketoshi Kawabe

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Abstract

Enhanced ratio control in a toroidal drive of a T-CVT is provided. A factor of proportionality is computed by which a trunnion axial displacement and a T-CVT ratio rate are related. A filter in the form of a characteristic equation is established. This filter includes a physical quantity indicative of the T-CVT ratio and a physical quantity indicated by an actuator command, as inputs, a quasi-state quantity, as a state quantity, and a transition coefficient for the quasi-state quantity. The transition coefficient includes an observer gain. The quasi-state quantity is computed using the filter. An estimated quantity of a system state quantity of the T-CVT is computed using the quasi-state quantity, the observer gain, and a trunnion angular position. The system state quantity includes at least the first physical quantity. The observer gain is corrected in response to the factor of proportionality to keep the transition coefficient unaltered.

Claims20

Dependent claims

A method for enhanced ratio control in a toroidal drive of a toroidal-type continuously variable transmission (T-CVT) including a ratio control element positionable in response to an actuator command to establish various ratios between input and output shaft speeds of the T-CVT, the toroidal drive having toroidal discs defining a toroidal cavity, and traction roller assemblies having pivot trunnions rotatably supporting traction rollers disposed in the toroidal cavity and engaged between the toroidal discs, the method comprising:

computing a factor of proportionality by which a first physical quantity and a second physical quantity are related,
the first physical quantity being a trunnion axial displacement of a predetermined one of the pivot trunnions, the second physical quantity being indicative of a ratio rate of the ratio between the input and output shaft speeds of the T-CVT;
establishing a filter in the form of a characteristic equation that includes a third physical quantity and a fourth physical quantity, as inputs, a quasi-state quantity, as a state quantity, and coefficients including a transition coefficient for the quasi-state quantity, the transition coefficient including an observer gain,
the third physical quantity being indicative of the ratio between the input and output shaft speeds of the T-CVT, the fourth physical quantity being indicated by the actuator command;
computing the quasi-state quantity using the filter;
computing an estimated quantity of a system state quantity of the T-CVT using the quasi-state quantity, the observer gain, and a fifth physical quantity indicative of a trunnion angular position of the predetermined pivot trunnion, the system state quantity including at least the first physical quantity;
and
correcting the observer gain in response to the factor of proportionality to keep the transition coefficient unaltered.

5 more elements

A system for enhanced ratio control in a toroidal drive of a toroidal-type continuously variable transmission (T-CVT) including a ratio control element positionable in response to an actuator command to establish various ratios between input and output shaft speeds of the T-CVT, the toroidal drive having toroidal discs defining a toroidal cavity, and traction roller assemblies having pivot trunnions rotatably supporting traction rollers disposed in the toroidal cavity and engaged between the toroidal discs, the system comprising:

a controller;
and
a computer readable storage media having data stored thereon representing instructions executable by the controller to
compute a factor of proportionality by which a first physical quantity and a second physical quantity are related,
the first physical quantity being a trunnion axial displacement of a predetermined one of the pivot trunnions, the second physical quantity being indicative of a ratio rate of the ratio between the input and output shaft speeds of the T-CVT;
establish a filter in the form of a characteristic equation that includes a third physical quantity and a fourth physical quantity, as inputs, a quasi-state quantity, as a state quantity, and coefficients including a transition coefficient for the quasi-state quantity, the transition coefficient including an observer gain,
the third physical quantity being indicative of the ratio between the input and output shaft speeds of the T-CVT, the fourth physical quantity being indicated by the actuator command;
compute the quasi-state quantity using the filter;
compute an estimated quantity of a system state quantity of the T-CVT using the quasi-state quantity, the observer gain, and a fifth physical quantity indicative of a trunnion angular position of the predetermined pivot trunnion, the system state quantity including at least the first physical quantity;
and
correct the observer gain in response to the factor of proportionality to keep the transition coefficient unaltered.

8 more elements

computing a factor of proportionality by which a first physical quantity and a second physical quantity are related,
the first physical quantity being a trunnion axial displacement of a predetermined one of the pivot trunnions, the second physical quantity being indicative of a ratio rate of the ratio between the input and output shaft speeds of the T-CVT;
establishing a filter in the form of a characteristic equation that includes a third physical quantity and a fourth physical quantity, as inputs, a quasi-state quantity, as a state quantity, and coefficients including a transition coefficient for the quasi-state quantity, the transition coefficient including an observer gain,
the third physical quantity being indicative of the ratio between the input and output shaft speeds of the T-CVT, the fourth physical quantity being indicated by the actuator command;
computing the quasi-state quantity using the filter;
computing an estimated quantity of a system state quantity of the T-CVT using the quasi-state quantity, the observer gain, and a fifth physical quantity indicative of a trunnion angular position of the predetermined pivot trunnion, the system state quantity including at least the first physical quantity;
generating a correction coefficient in response to the factor of proportionality;
and
determining the observer gain in response to the correction coefficient to keep the transition coefficient unaltered.

6 more elements

In a toroidal drive of a toroidal-type continuously variable transmission (T-CVT) including a ratio control element positionable in response to an actuator command to -establish various ratios between input and output shaft speeds of the T-CVT, the toroidal drive having toroidal discs defining a toroidal cavity, and traction roller assemblies having pivot trunnions rotatably supporting traction rollers disposed in the toroidal cavity and engaged between the toroidal discs:

a computer readable storage media having stored thereon data representing instructions executable by a computer for enhanced ratio control in the toroidal drive, comprising:
instructions for computing a factor of proportionality by which a first physical quantity and a second physical quantity are related,
the first physical quantity being a trunnion axial displacement of a predetermined one of the pivot trunnions, the second physical quantity being indicative of a ratio rate of the ratio between the input and output shaft speeds of the T-CVT;
instructions for establishing a filter in the form of a characteristic equation that includes a third physical quantity and a fourth physical quantity, as inputs, a quasi-state quantity, as a state quantity, and coefficients including a transition coefficient for the quasi-state quantity, the transition coefficient including an observer gain,
the third physical quantity being indicative of the ratio between the input and output shaft speeds of the T-CVT, the fourth physical quantity being indicated by the actuator command;
instructions for computing the quasi-state quantity using the filter;
instructions for computing an estimated quantity of a system state quantity of the T-CVT using the quasi-state quantity, the observer gain, and a fifth physical quantity indicative of a trunnion angular position of the predetermined pivot trunnion, the system state quantity including at least the first physical quantity;
and
instructions for correcting the observer gain in response to the factor of proportionality to keep the transition coefficient unaltered.

6 more elements

Dependencies are inferred from the claim text.