Grade-Compensated Drive Torque for Consistent One-Pedal Deceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In one pedal driving mode, vehicles face challenges in maintaining consistent deceleration and accelerator feel across varying grades due to the lack of effective grade compensation, leading to inconsistent stopping profiles and pedal feedback, especially when traveling uphill or downhill.
Innovation Solution
A controller system that uses a combination of speed-based feedback and grade-compensating feedforward control to adjust torque production based on the difference between drivetrain and accelerometer-derived accelerations, estimating the effect of road grade and scheduling additional torque to compensate for it, ensuring consistent deceleration and normalized accelerator feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grade compensation is not implemented in one-pedal driving mode, then the control system remains simple, but deceleration consistency and accelerator feel vary significantly across different road grades
Solution Approach 1:
The system uses feedback control by continuously monitoring vehicle speed and comparing it with reference values, then adjusting torque production based on the deviation. The controller compares actual vehicle deceleration with expected deceleration and modifies generator torque accordingly to maintain consistent stopping profiles across different grades.
Solution Approach 2:
The system uses readily available sensor data (wheel speed sensor and accelerometer) to automatically detect road grade conditions and adjust torque production without requiring additional grade detection sensors or complex manual intervention. The existing vehicle sensors serve multiple purposes including grade compensation.
2Ease of operation
If grade compensation is implemented using sensor data, then accelerator feel and deceleration profiles improve, but the control algorithm complexity increases
Solution Approach 1:
The system replaces complex mechanical grade detection mechanisms with electronic sensor-based detection. Instead of using mechanical inclinometers or grade sensors, the system uses electrical signals from existing wheel speed and accelerometer sensors to detect road grade and compute compensation torque through electronic control algorithms.
Solution Approach 2:
The control system performs multiple functions using the same sensor inputs: it monitors vehicle speed for basic cruise control, detects road grade through acceleration differences, and adjusts torque for both propulsion and regenerative braking. The same accelerometer and wheel speed sensors serve multiple control objectives including grade compensation, stability control, and basic speed regulation.
3Use of energy by moving object
If regenerative braking is used without grade compensation, then energy recovery is achieved, but stopping profiles become inconsistent on uphill and downhill sections
Solution Approach 1:
The system performs preliminary grade detection and compensation torque calculation before the vehicle needs to decelerate. By continuously monitoring acceleration differences from available sensors, the system pre-computes the grade compensation torque that will be applied during regenerative braking, ensuring consistent stopping profiles from the onset of brake application.
Solution Approach 2:
The system dynamically changes the torque parameter based on detected road grade conditions. When uphill grade is detected, the system adjusts generator torque to account for gravitational assistance; when downhill grade is detected, it increases generator torque to compensate for gravitational acceleration, maintaining consistent deceleration characteristics across varying grades.
Data Source
AI summary
A vehicle includes a powertrain and a controller. The controller, responsive to a parameter indicative of a grade on which the vehicle is travelling having a value greater than a threshold, and a given accelerator pedal input, commands the powertrain to produce an amount of drive torque for the vehicle that is based on the value.