Patent ID: 8532889

Claim:
A machine having a variator and a variator controller for controlling an output torque of the variator via a hydraulic actuator responsive to an actuator pressure signal, the variator controller comprising: a processor system including: a digital data processor; a first data input connected to a circuit pressure sensor to receive a signal related to a hydraulic pressure within an internal hydraulic circuit of the variator; a second data input connected to a pump speed sensor to receive a signal related to a rotational speed of a variator input shaft; a third data input connected to a motor speed sensor to receive a signal related to a rotational speed of a variator output shaft; a fourth data input connected to an operator interface to receive a signal related to a desired torque; a fifth data input connected to receive a signal corresponding to a first mapped control pressure based on data received at the first, second, and third data inputs; and a computer-readable memory having stored thereon computer-executable instructions to cause the digital data processor system to execute a method comprising: receiving an indication of a first desired torque; evaluating a plurality of parameters related to operation of the variator; reading a map linking the plurality of parameters to a first mapped value for the actuator pressure signal, wherein the first desired torque is associated with the first mapped value; applying the first mapped value to the hydraulic actuator as an actuator pressure signal; measuring a first actual output torque of the variator and comparing the first actual output torque to the first desired output torque to derive an error value; deriving, based on the error value, a supplement value comprising one of the group consisting of: yielding a pressure supplement value by multiplying the error value by a gain factor to produce the pressure supplement value; and a motor torque supplement value; receiving an indication of a second desired torque; reevaluating the plurality of parameters related to operation of the variator; reading the map linking the plurality of variables to a second mapped value for the actuator pressure signal, wherein the second desired torque is associated with the second mapped value; modifying the second mapped value via the pressure supplement value to produce an adjusted actuator pressure signal; and applying the adjusted actuator pressure signal to the hydraulic actuator to control the output torque of the variator.