Corrective control system and method for liquid pressure control apparatus in automatic transmission

A corrective control method for a liquid pressure control apparatus for a control valve unit, comprising:

• controlling an output liquid pressure of the control valve unit on the basis of a current value which is an electrical signal generated in accordance with an output pressure demand value P* determined according to a calculation process executed within a control unit;
• outputting respectively separated current values to a solenoid drive circuit of the control valve unit;
• actually measuring the output liquid pressure values for the outputted respective current values;
• calculating an output liquid pressure theoretical value for each of the outputted current values by referring to preset fundamental maps, each fundamental map representing a relationship between the current value and the output liquid pressure theoretical value;
• presetting the fundamental maps on the basis of a hysterisis characteristic that each individual control valve unit has, the hysterisis characteristic being exhibited in such a manner that the output liquid pressure actually measured value which follows along a first hysterisis loop when the current value is increased toward a larger value is different from that which follows along a second hysterisis loop when the current value is, in turn, decreased toward a smaller value from the larger value;
• approximating a relationship between the output liquid pressure actually measured value and the output liquid pressure theoretical value for each of the same current values to a first-order function;
• calculating a coefficient of the approximated first-order function and a constant thereof;
• storing the calculated coefficient and constant therein;
• and
• correcting the electrical signal which accords with the output liquid pressure demand value on the basis of the stored coefficient and constant, wherein each of the fundamental maps to be referred to when calculating the output liquid pressure theoretical value is a map representing a relationship between the output liquid pressure actually measured value and a current average value, the current average value being calculated to be an average of the current between the current value in the first hysterisis loop of the hysterisis characteristic and that in the second hysterisis loop thereof with respect to each of the same output pressure actually measured values.

A corrective control system for a liquid pressure control apparatus of a control valve unit, comprising:

• liquid pressure controlling means for controlling an output liquid pressure of the control valve unit on the basis of a current value which is an electrical signal generated in accordance with an output pressure demand value P* determined according to a calculation process executed within a control unit;
• output liquid pressure actually measuring means for outputting respectively separated current values to a solenoid drive circuit of the control valve unit and for actually measuring the output liquid pressure values for the outputted respective current values;
• output pressure theoretical value calculating means for calculating an output liquid pressure theoretical value for each of the current values outputted by the actually measuring means by referring to preset fundamental maps, each fundamental map representing a relationship between the current value and the output liquid pressure theoretical value;
• fundamental map presetting means for presetting the fundamental maps on the basis of a hysterisis characteristic that each individual control valve unit has, the hysterisis characteristic being exhibited in such a manner that the output liquid pressure actually measured value which follows along a first hysterisis loop when the current value is increased toward a larger value is different from that which follows along a second hysterisis loop when the current value is, in turn, decreased toward a smaller value from the larger value;
• corrective term calculating means for approximating a relationship between the output liquid pressure actually measured value and the output liquid pressure theoretical value for each of the same current values to a first-order function and for calculating a coefficient of the approximated first-order function and a constant thereof;
• storing means for storing stores the calculated coefficient and constant therein;
• and
• correcting means for correcting the electrical signal which accords with the output liquid pressure demand value on the basis of the coefficient and constant stored in the storing means, wherein each of the fundamental maps referred to by the output liquid pressure theoretical value calculating means is a map representing a relationship between the output liquid pressure actually measured value and a current average value, the current average value being calculated to be an average of the current between the current value in the first hysterisis loop of the hysterisis characteristic and that in the second hysterisis loop thereof with respect to each of the same output pressure actually measured values.