Electric Vehicle Motor Controller Shifting Shock Mitigation
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Solution Overview
Problem
In electric vehicles with manual transmissions, shifting operations often result in shifting shocks due to improper clutch operations or gear changes, leading to inadequate rotational speed control and increased impact during gear shifts.
Innovation Solution
The electric motor is controlled to mitigate shifting impacts by adjusting its rotational speed based on the estimated reduction gear ratio and clutch state, allowing for smooth transitions between torque and rotational speed control, regardless of clutch engagement, thereby reducing angular velocity differences and improving acceleration responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is engaged during shifting operation, then the driving power transmission is continuous, but the rotational speed control cannot be performed properly causing shifting shock
Solution Approach 1:
The control device changes the rotational speed parameter of the electric motor based on the shifting operation detection and estimated gear ratio. When shifting is detected, the system adjusts the motor rotational speed to match the speed required for the target gear, thereby eliminating shifting shock while maintaining continuous power transmission with the clutch engaged.
Solution Approach 2:
The system uses feedback from the shifting operation detection (via shift lever position or clutch switch) and continuously estimates the current and target gear ratios to dynamically adjust motor control. This closed-loop control ensures the motor speed adapts to the shifting state, preventing shock while maintaining transmission continuity.
2Ease of operation
If the clutch is disengaged during shifting operation, then the rotational speed control can be performed, but the driving power transmission is interrupted causing impact
Solution Approach 1:
The control device performs preliminary rotational speed adjustment before the shifting operation completes. By detecting the shifting state in advance and pre-adjusting the motor rotational speed to match the target gear ratio, the system prepares the power transmission path to minimize impact when the clutch re-engages, thereby maintaining both smooth shifting and continuous power transmission.
3Speed
If traditional torque control is used during shifting, then the accelerator response is maintained, but the shifting shock cannot be mitigated
Solution Approach 1:
The control system dynamically switches between torque control and rotational speed control based on the detected shifting state. During normal operation, torque control maintains accelerator responsiveness. When shifting is detected, the system transitions to rotational speed control to mitigate shock, then returns to torque control after shifting completes, thereby achieving both rapid response and smooth operation.
Data Source
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AI summary
An electric vehicle comprises an electric motor for generating driving power transmitted to a drive wheel via a driving power transmission path; a manual transmission which selects one driving power transmission path from among plural driving power transmission paths and shifts a present driving power transmission path to the selected driving transmission path, in response to a rider's operation for changing a speed of the driving power from the electric motor; a shifting state detecting device for detecting whether the manual transmission is in a driving power transmission state in which the manual transmission has completed shifting of the driving power transmission path or in a driving power cut-off state in which the manual transmission is shifting the driving power transmission path; and a motor controller for executing a first control routine to control the electric motor; wherein in the first routine, torque control of the electric motor is performed when the shifting state detecting device detects that the manual transmission is in the driving power transmission state, and mitigation control of the electric motor is performed to mitigate an impact caused by shifting of the driving power transmission path, when the shifting state detecting device detects that the manual transmission is in the driving power cut-off state, the mitigation control being different from the torque control.