Electric Vehicle Wheel Force Feedback for Consistent Acceleration
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Solution Overview
Problem
Motor vehicles with electric or hybrid traction lack the ability to adapt torque application based on driving conditions, leading to varying sensations of acceleration or deceleration due to resistive forces like slope inclination, resulting in inconsistent vehicle behavior for the same accelerator pedal depression.
Innovation Solution
A method that converts accelerator pedal depression into a reference force, calculates a correction force based on the difference between desired and actual accelerations, and applies this correction force to the wheels to compensate for resistive forces, ensuring consistent acceleration or deceleration sensations regardless of slope or speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open-loop torque control is used, then the vehicle responds to accelerator pedal depression with a predetermined torque, but the vehicle behavior varies depending on resistive forces such as slope inclination
Solution Approach 1:
The patent implements a closed-loop control system that measures actual vehicle acceleration using an accelerometer and compares it with reference acceleration calculated from accelerator pedal position. A correction force is then applied based on the acceleration error to compensate for resistive forces. This feedback mechanism ensures consistent vehicle behavior across different driving conditions while maintaining manageable system complexity through efficient sensor utilization and control algorithms.
2Ease of operation
If no adaptation to driving conditions is implemented, then the control system remains simple, but the driver experiences varying acceleration sensations for the same pedal depression
Solution Approach 1:
The system uses an accelerometer to measure actual acceleration and feeds this information back to the control unit. The control unit calculates the difference between actual and reference acceleration, then applies a correction force through the electric motor to achieve the desired acceleration sensation. This feedback-based approach significantly improves driving comfort by providing consistent acceleration feedback to the driver while adding only moderate system complexity through the integration of a single accelerometer sensor and associated control logic.
3Adaptability or versatility
If closed-loop acceleration control is implemented, then consistent acceleration sensation is achieved, but the system complexity increases due to additional sensors and control algorithms
Solution Approach 1:
The patent employs a feedback control mechanism where an accelerometer measures actual acceleration, which is compared against reference acceleration derived from accelerator pedal position. The control unit calculates an acceleration error and generates a correction force applied by the electric motor to eliminate the error. This approach achieves sophisticated acceleration compensation capability while managing system complexity by leveraging existing vehicle sensors and implementing efficient control algorithms that process data in real-time without requiring overly complex hardware architectures.
Data Source
Figure 1~2
AI summary
This method for compensating resistive forces Fres applied to a vehicle (V) including an electric motor comprises the following steps: - Conversion (step 1) of a representative value (X) of the depressment of an accelerator pedal into a reference force (Fref); - Application (step 3) of the reference force (Fref) to at least one drive wheel of the vehicle (V); - Determination (step 5) of a reference acceleration (aref) by dividing the reference force (Fref) by the mass of the vehicle (V); - Measurement (step 7) of the effective acceleration (aeff) of the vehicle (V); - Calculation (step 9) of a correction force (Fcorr) from the reference and effective accelerations (aref; aeff); and - Application (step 11) of the correction force (Fcorr) to said wheel.