Electric Vehicle Motor Torque Control for Uphill Slip Prevention
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Solution Overview
Problem
Electric vehicles face the challenge of slipping backward on uphill slopes due to the lack of output torque when the accelerator pedal is released, which can lead to safety issues.
Innovation Solution
A method and apparatus for controlling motor output torque in electric vehicles that detect the tilt angle, current speed, and accelerator-pedal travel value to calculate and maintain a minimum torque necessary to prevent slipping, even when the accelerator pedal is not pressed, by using sensors and a motor controller to adjust the torque based on equations that account for vehicle mass, gravity, and gear position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the motor does not need idle speed to ensure running, then energy efficiency is improved, but the vehicle may slip backward on slopes when accelerator is released
Solution Approach 1:
The control system performs preliminary detection of slope conditions (tilt angle) and calculates the required creep torque before the vehicle actually slips backward. By detecting the tilt angle θ and calculating T1 = mg·sin(θ)·r in advance, the system prepares the necessary counteracting torque to prevent backward slipping, rather than reacting after the problem occurs.
Solution Approach 2:
The system continuously monitors the tilt angle θ via tilt angle detection means and feeds this information back to the control unit. Based on this feedback, the control unit dynamically adjusts the motor torque to maintain T ≥ T1, ensuring the vehicle remains stable on slopes without requiring traditional idle speed operation.
2Loss of energy
If the motor provides zero torque when accelerator is released, then energy consumption is reduced, but safety is compromised on uphill sections
Solution Approach 1:
The system applies different torque strategies based on local conditions: on flat terrain, the motor operates with minimal or zero torque when the accelerator is released to save energy; on sloped terrain detected by tilt angle sensor, the system locally adjusts to provide creep torque T ≥ T1 to prevent backward slipping. This localized adaptation resolves the contradiction between energy savings and safety.
Solution Approach 2:
The control system changes the torque parameter dynamically based on the tilt angle parameter θ. When θ exceeds a threshold indicating uphill condition, the system changes from zero-torque mode to creep-torque mode, calculating T1 = mg·sin(θ)·r and ensuring T ≥ T1. This parameter-based control allows the system to optimize energy consumption while maintaining safety under varying conditions.
3Device complexity
If conventional torque control T = T2 × Gain is used, then simple control logic is maintained, but insufficient torque is provided on slopes to prevent slipping
Solution Approach 1:
The control logic transitions from a static formula T = T2 × Gain to a dynamic control strategy that adapts to slope conditions. The system dynamically determines torque requirements based on real-time tilt angle detection, calculating T1 = mg·sin(θ)·r and adjusting torque to ensure T ≥ T1 when on slopes, while maintaining T = T2 × Gain on flat terrain. This dynamic adaptation increases output torque magnitude when needed without significantly complicating the overall control structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures the vehicle does not slip backward in uphill mode, enhancing safety and comfort by providing a controlled output torque that is greater than the minimum required, even when the accelerator pedal is released, thereby preventing accidents.
Implementation Method 1
detecting a tilt angle value θ, a current vehicle speed value V and an accelerator-pedal travel value Gain of the vehicle
Implementation Method 2
calculating a minimum torque T1 required for preventing the vehicle from slipping backward under the tilt angle value θ and the current vehicle speed value V
Implementation Method 3
controlling the motor to output the calculated output torque T
Data Source
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AI summary
A method and an apparatus for controlling output torque of a motor for an electric vehicle in uphill mode, the method comprises: detecting a tilt angle value U, a current vehicle speed value V and an accelerator-pedal travel value Gain of the vehicle, determining whether the vehicle is in uphill mode or not, and if the result is positive, then calculating a minimum torque T1 required for preventing the vehicle from slipping backward under the tilt angle value 0 and the current vehicle speed value V, obtaining a maximum output torque T2, calculating an output torque T of the motor based on T1, T2 and Gain, and controlling the motor to output the calculated output torque T. With the method and apparatus in accordance with the present invention, when the electric vehicle is in uphill mode, even if the accelerator-pedal travel value is zero, the vehicle will not slip backward.