A control device for a multi-stage transmission for an electric vehicle is provided. The control device includes a controller configured to calculate a driving force of a drive motor when entering a shift mode and to determine a shift time point based on the calculated driving force, and the multi-stage transmission configured to perform shifting at the determined shift time point.

A transmission includes an input shaft and an output shaft, the input shaft selectively accepting a torque input from a prime mover, and the output shaft selectively providing torque output to a driveline. A controller determines a shaft displacement angle representing an angle value of rotational displacement difference between at least two shafts of the transmission, and performs a transmission operation responsive to the shaft displacement angle.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

Methods and systems are provided for controlling and diagnosing a mechanical vehicle component. In one example, a method may include determining a vehicle speed and a plurality of clutch position settings at a diagnostic controller, and identifying unauthorized conditions based on these determinations. Further, the diagnostic controller may trigger an active fault state of the mechanical vehicle component in order to avoid unauthorized conditions that may lead to unwanted or unanticipated changes in vehicle motion.

Provided is a transmission device monitoring system including: a diagnostic frequency estimation unit that extracts a plurality of diagnostic frequency candidate groups from a frequency region separated by a specific frequency or more using at least current information on a motor, a gear ratio of a transmission device, and the number of stages of the transmission device, and estimates a frequency satisfying a specific relationship from frequencies obtained in the plurality of diagnostic frequency candidate groups as a diagnostic frequency; and an abnormality diagnosis unit that diagnoses abnormality of the transmission device using at least the one diagnostic frequency estimated by the diagnostic frequency estimation unit.

Provided is a transmission device monitoring system including: a diagnostic frequency estimation unit that extracts a plurality of diagnostic frequency candidate groups from a frequency region separated by a specific frequency or more using at least current information on a motor, a gear ratio of a transmission device, and the number of stages of the transmission device, and estimates a frequency satisfying a specific relationship from frequencies obtained in the plurality of diagnostic frequency candidate groups as a diagnostic frequency; and an abnormality diagnosis unit that diagnoses abnormality of the transmission device using at least the one diagnostic frequency estimated by the diagnostic frequency estimation unit.

A vehicle control device controls a vehicle provided with a transmission having a direct gear and normal gears including an overdrive gear having a lower gear ratio than the direct gear. The device includes a travel segment determination unit which determines a forward travel segment having a different road slope from a current travel segment, a current gear position selection unit that selects a current gear position based on a travel resistance of the vehicle, a forward gear position selection unit that selects a forward gear position based on a travel resistance in the forward travel segment, and a shift control unit that selects whether or not to upshift the transmission based on a situation until the vehicle reaches the forward travel segment, when an upshift to the overdrive gear is newly selected in a case where the current gear position and the forward gear position are the direct gear.

In one aspect, a method of controlling gear shifting in response to a driving mode change, the method including determining a maximum number of allowable low-level gear-shifting steps according to a result of determining a state of a transmission, computing an immediate post-gear-shifting expected speed of a turbine for each step included that is within the maximum number of allowable low-level gear-shifting steps, using a current speed of an output shaft of the transmission and a gear ratio of each step and comparing the computed expected speed of the turbine with a preset allowable speed thereof for each step, setting the lowest-level gear-shifting step, among gear-shifting steps at which the expected speed of the turbine and the allowable speed thereof satisfy a predetermined condition, is set to be a target gear-shifting step, and executing gear-shifting control for shifting a current gear-shifting step down to the target gear-shifting step.

In one aspect, a method of controlling gear shifting in response to a driving mode change, the method including determining a maximum number of allowable low-level gear-shifting steps according to a result of determining a state of a transmission, computing an immediate post-gear-shifting expected speed of a turbine for each step included that is within the maximum number of allowable low-level gear-shifting steps, using a current speed of an output shaft of the transmission and a gear ratio of each step and comparing the computed expected speed of the turbine with a preset allowable speed thereof for each step, setting the lowest-level gear-shifting step, among gear-shifting steps at which the expected speed of the turbine and the allowable speed thereof satisfy a predetermined condition, is set to be a target gear-shifting step, and executing gear-shifting control for shifting a current gear-shifting step down to the target gear-shifting step.