Patent ID: 6779540
Filing Date: 2004-08-24
Classification: F16H,G05D,Y10T

Abstract:
A corrective control system for a liquid pressure control apparatus of a control valve unit, comprising:a liquid pressure controlling section that controls 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; an output liquid pressure actually measuring section that outputs respectively separated current values to a solenoid drive circuit of the control valve unit and actually measures the output liquid pressure values for the outputted respective current values; an output pressure theoretical value calculating section that calculates an output liquid pressure theoretical value for each of the current values outputted by the actually measuring section by referring to preset fundamental maps, each fundamental map representing a relationship between the current value and the output liquid pressure theoretical value; a corrective term calculating section that approximates 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 calculates a coefficient of the approximated first-order function and a constant thereof; a storing section that stores the calculated coefficient and constant therein; and a correcting section that corrects the electrical signal which accords with the output liquid pressure demand value on the basis of the coefficient and constant stored in the storing section; a fundamental map presetting section that presets the fundamental maps on the basis of a hysterisis characteristic that each individual control valve unit has, the hysteresis characteristic being exhibited in such a manner that the output liquid pressure actually measured value which follows along a first hysteresis 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; a linear point setting section that calculates the current average values between the current values in the first hysteresis loop and those in the second hysterisis loop which correspond to at least two output liquid pressure actually measured values and sets linear points determined from the output liquid pressure actually measured value and the current average value which corresponds to the two output liquid pressure actually measured values in a linear region of the hysteresis characteristic; and a linearity characteristic deriving section that derives a first-order function that passes through the set two linear points, and wherein the fundamental map presetting section presets the fundamental maps using the relationship between the output liquid pressure actually measured value and the current average value and using the relationship on the derived first-order function at a lower output pressure side than the linear region.