EV Shift Control Using Signal Torque for Driver Feedback
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Solution Overview
Problem
Electric vehicles that do not output creep torque or perform creeping-cut make drivers feel uncomfortable or uneasy when shifting from non-traveling to traveling positions due to the lack of feedback on shift position changes, as they cannot sense the fluctuations in driving force typically provided by creep torque in conventional vehicles.
Innovation Solution
A control device and method for electric vehicles that uses a motor to output signal torque, detectable by the driver, to indicate shift position changes, maintaining the vehicle's state and generating vibrations or accelerations that simulate the feedback experienced in conventional vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If creeping-cut is performed to reduce power consumption, then power consumption is reduced, but driver comfort deteriorates due to lack of feedback on shift position changes
Solution Approach 1:
The control device performs periodic output of creep torque at predetermined intervals even during creeping-cut state. This periodic action creates detectable vibrations that provide feedback to the driver about shift position changes, resolving the contradiction between reducing power consumption and maintaining driver comfort.
Solution Approach 2:
The control device uses vibration detection to determine whether the driver has operated the shift lever, and based on this feedback, controls the output of creep torque. This feedback mechanism ensures that driver actions are recognized and appropriate torque is provided, maintaining comfort while managing power consumption.
2Use of energy by moving object
If creep torque is not output to reduce power consumption, then power consumption is reduced, but the driver cannot sense shift position changes
Solution Approach 1:
Instead of continuous creep torque output, the control device implements periodic output at predetermined intervals. This periodic action generates vibrations that convey shift position information to the driver while significantly reducing overall power consumption compared to continuous output.
Solution Approach 2:
The control device utilizes mechanical vibrations generated by periodic creep torque output as a medium to transmit information about shift position changes to the driver. These vibrations serve as a tactile feedback mechanism that replaces the continuous torque sensation in conventional vehicles.
3Ease of operation
If signal torque is continuously output to provide shift feedback, then driver comfort is improved, but power consumption increases
Solution Approach 1:
The control device outputs signal torque periodically at predetermined intervals rather than continuously. This periodic action maintains driver comfort by providing regular feedback about shift position changes while significantly reducing power consumption compared to continuous signal torque output.
Solution Approach 2:
The control device applies signal torque partially - only when needed for feedback purposes - rather than continuously. This partial action provides sufficient information to the driver about shift position changes while minimizing unnecessary energy consumption.
Data Source
AI summary
In a control device of an electric vehicle including a motor, driving wheels, a shifting device that is operated by a driver and selectively sets one of two shift positions of a traveling position that generates driving force by transmitting output torque of the motor to the driving wheels, and a non-traveling position that does not generate driving force without transmitting the output torque to the driving wheels, a controller causes the motor to output signal torque that enables the driver to sense a change in a vehicle behavior accompanied with switching of the shift position when the driver switches the shift position.