EV Driving Force Control Maps for Clutch-Like Torque Response
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Solution Overview
Problem
Drivers accustomed to internal combustion engine vehicles experience discomfort when operating electric vehicles due to differences in torque control behavior between electric and engine vehicles, as the adjustment of the electric vehicle's torque control lever does not effectively match the behavior of an engine vehicle's clutch lever.
Innovation Solution
An electric vehicle with multiple control maps stored in a storage device that correspond to different operation amounts of a secondary operation member, allowing the control device to calculate and adjust driving force based on vehicle speed and accelerator operation, thereby reducing discomfort by mimicking the behavior of an engine vehicle's clutch lever operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the adjustment lever controls the torque of the electric motor at a rate in accordance with the operation amount, then the torque control is simple and direct, but the driver accustomed to engine vehicles feels discomfort due to the large difference from clutch lever behavior
Solution Approach 1:
The patent applies dynamics by making the torque control characteristics changeable through multiple control maps. Each map defines different torque reduction rates corresponding to different operation amounts of the second operation member (clutch lever). The control device selects appropriate maps based on the operation amount, enabling the system to adapt its torque control behavior dynamically. This resolves the contradiction by allowing the torque control to be simple and direct when needed while also providing adaptability to match engine vehicle clutch lever behavior when required.
Solution Approach 2:
The patent changes the parameter of torque control characteristics by storing multiple control maps with different torque reduction rates. Each control map corresponds to a specific operation amount range of the second operation member. By switching between these maps based on the operation amount, the system changes its control parameters to achieve either simple direct control or engine-vehicle-like behavior, thereby resolving the contradiction between ease of operation and adaptability.
2Adaptability or versatility
If multiple control maps are stored to match engine vehicle behavior, then driver discomfort is reduced, but the control system complexity increases
Solution Approach 1:
The patent segments the torque control function by dividing it into multiple control maps, where each map handles a specific operation amount range of the second operation member. This segmentation allows the complex adaptability requirement to be broken down into manageable pieces, with each map containing simplified control logic. The control device only needs to select the appropriate segmented map based on the current operation amount, reducing the overall system complexity while maintaining high adaptability.
3Adaptability or versatility
If the torque reduction rate is high to match clutch lever behavior, then engine vehicle compatibility is improved, but the vehicle stability decreases
Solution Approach 1:
The patent applies local quality by assigning different torque reduction rates to different operation amount ranges through multiple control maps. Each map is optimized for its specific range: some maps provide higher torque reduction rates to match clutch lever behavior, while others provide lower rates to maintain vehicle stability. This local optimization resolves the contradiction by allowing high adaptability in certain operating conditions while ensuring stability in others.
Data Source
AI summary
A plurality of control maps respectively corresponding to a plurality of lever operation amounts are stored in a storage device. Each control map defines a driving force to be output from an electric motor such that the driving force corresponds to an accelerator operation amount and a vehicle speed. A control device uses a control map corresponding to an actual lever operation amount among the plurality of control maps and thereby calculates the driving force to be output from the electric motor based on an actual accelerator operation amount and an actual vehicle speed from the control map. This vehicle can alleviate discomfort caused when a driver accustomed to an engine vehicle operates an electric vehicle.