A controller constitutes a control device for continuously variable transmission for executing a feedback control of a transmission so that an actual speed ratio reaches a target speed ratio. The controller includes a first phase lead compensator and a second phase lead compensator configured to perform phase lead compensation of a feedback primary command pressure, and a peak value frequency determination unit configured to change a peak value frequency according to a speed ratio.

A shift control device has stepless and stepped shift modes in which a transmission gear ratio of a continuously variable transmission is controlled in stepless and stepwise fashions, respectively, and includes a mode setting unit that switches the shift mode to the stepped shift mode if an engine rotation speed in the stepless shift mode exceeds a switch threshold, a correction-value setting unit that sets a correction value based on the engine rotation speed if the shift mode is to be switched to the stepped shift mode, a shift-threshold setting unit that sets a shift threshold by adding the correction value to the switch threshold if the shift mode is to be switched to the stepped shift mode, and an upshift controller that switches the transmission gear ratio toward a higher side when the engine rotation speed in the stepped shift mode reaches the shift threshold.

A transmission ratio controller includes circuitry including a transmission ratio calculator and a monitor. The transmission ratio calculator calculates a transmission ratio using a first transmission ratio map when a specified parameter satisfies a first condition, and using a second transmission ratio map when the specified parameter satisfies a second condition. When the specified parameter satisfies the first condition, the internal combustion engine is in a first state. When the specified parameter satisfies the second condition, the internal combustion engine is in a second state. In the first state, the monitor calculates a hypothetical transmission ratio using the second transmission ratio map based on the second state. On a condition that the transmission ratio calculated in the first state differs from the hypothetical transmission ratio by a predetermined reference value or greater, the monitor determines that the transmission ratio has a possibility of differing in accordance with the specified parameter.

A transmission ratio controller includes circuitry that includes a transmission ratio calculator calculating a request transmission ratio, a transmission ratio instructor transmitting a control signal, and an abnormality determiner. The request transmission ratio is calculated using a first transmission ratio map when a specified parameter satisfies a first condition, and a second transmission ratio map when the specified parameter satisfies a second condition. The internal combustion engine is in a first state when the specified parameter satisfies the first condition, and in a second state when the specified parameter satisfies the second condition. In the first state, the abnormality determiner calculates a hypothetical transmission ratio using the second transmission ratio map based on the second state. The abnormality determiner determines an abnormality based on a comparison of the hypothetical transmission ratio with at least one of the request transmission ratio, an instruction transmission ratio, or an actual transmission ratio.

A transmission ratio controller includes circuitry. The circuitry includes a transmission ratio calculator configured to calculate a request transmission ratio to a transmission mechanism, a transmission ratio instructor configured to output a control signal based on the request transmission ratio, and an abnormality determiner configured to determine whether a transmission ratio of the transmission mechanism is abnormal. At least two of the request transmission ratio, an instruction transmission ratio corresponding to the control signal, or an actual transmission ratio achieved by the transmission mechanism are transmission ratios subject to comparison. The abnormality determiner is configured to determine that when a difference obtained by comparing the transmission ratios subject to comparison is greater than or equal to a predetermined specified value, the transmission ratio of the transmission mechanism is abnormal.

A tidal current energy converter including an infinitely variable transmission (IVT) control system and a hybrid vertical axis wind (or water) turbine (VAWTs) apparatus. The hybrid VAWT apparatus includes a modified-Savonius (MS) rotor in the central region and a straight bladed H-type Darrieus rotor in the surrounding annular region. The IVT control system includes a nonlinear closed-loop control combined with an integral time-delay feedback control to adjust a speed ratio of the IVT. A speed ratio control for an IVT system involves a forward speed controller and/or a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

Described herein is a control system for a vehicle having an infinitely variable transmission (WT) having a ball planetary variator (CVP), providing a smooth and controlled operation. In some embodiments, the vehicle is a fork lift truck. An operator commands a brake pedal, an accelerator pedal, and a direction switch (or gear selector), which are evaluated by the control system to determine a current operating state of the vehicle. Some operating states include, forward drive, reverse drive, vehicle braking, automatic deceleration, inching, power reversal, vehicle hold, and park, among others.

A method is provided for estimating input torque and output torque in a continuously variable transmission having a variator. The method comprising the steps of determining (202) a transmission Input and/or output speed, calculating (204) the speed of each of a plurality of transmission components by reflecting the transmission input and/or output speed through the transmission to each of the plurality of transmission components, and calculating (208) the speed rate of change of each of the plurality of transmission components. The inertia torque of each of the plurality of transmission components is calculated (210) based upon its respective speed rate of change and a predetermined component inertia value (209). The method further comprises the steps of determining (211) a motor torque of the variator, and calculating (212) a transmission input torque and transmission output torque by reflecting the motor torque of the variator through the transmission to the transmission input and output. The calculated transmission Input and output torque values are adjusted (214) to account for the calculated inertia torque values of those of the plurality of transmission components which lie between the variator and the transmission input, and the variator and the transmission output, respectively.

A control method of a continuously variable transmission mounted on a vehicle includes performing advance compensation in a speed ratio control system of the continuously variable transmission, and making an advance amount according to a vibration frequency of torsional vibration of an input shaft of the continuously variable transmission which is the advance amount of the advance compensation variable in accordance with an operation state of the vehicle. A feedback gain of speed ratio control of the continuously variable transmission performed in the speed ratio control system is variable in accordance with an operation state of the vehicle. When the advance amount is made variable, the advance amount is made variable in accordance with the feedback gain.

A transmission controller of a toroidal continuously variable transmission includes a gain setting unit that adjusts a gain of closed-loop control for calculating a target value of a roller position in accordance with a change in a rotation speed of a disc in a first rotation speed range and a second rotation speed range higher than the first rotation speed range. The gain setting unit changes, in the first rotation speed range, the gain so that sensitivity of the closed-loop control decreases with an increase in the rotation speed, and changes, in the second rotation speed range, the gain so that a rate of decrease in the sensitivity of the closed-loop control with the increase in the rotation speed is smaller than that in the first rotation speed range.