Electric Motor Deceleration Control for Surface-Adaptive Traction
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Solution Overview
Problem
Electric vehicles lack a stable deceleration mechanism similar to engine braking, leading to excessive deceleration on certain surfaces, which can cause loss of traction or uncomfortable braking on slippery or soft terrains.
Innovation Solution
A control system that receives surface indicators and deceleration demands to determine a target vehicle deceleration, adjusting torque generator output to provide suitable deceleration based on terrain type, using a combination of regenerative braking and friction brakes to maintain stability and traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If regenerative braking is used to replicate engine braking effect, then deceleration capability is improved, but excessive deceleration occurs on slippery or soft surfaces causing loss of traction or wheel pitch
Solution Approach 1:
The control system dynamically adjusts the deceleration target based on detected surface conditions. When a slippery or soft surface is detected, the system automatically reduces the deceleration target to prevent excessive deceleration that would cause loss of traction or wheel pitch. This dynamic adaptation allows the vehicle to maintain stability while still providing effective deceleration on suitable surfaces.
Solution Approach 2:
The system changes the deceleration parameter based on surface conditions. By detecting surface type (e.g., slippery, soft, or normal surfaces), the control system modifies the target deceleration value accordingly. This parameter change ensures that deceleration remains within safe limits for the current surface conditions while maximizing energy recovery when conditions permit.
2Loss of time
If high deceleration is applied to stop the vehicle quickly, then stopping distance is reduced, but traction is lost on slippery surfaces
Solution Approach 1:
The control system continuously monitors surface conditions and adjusts deceleration commands based on this feedback. When slippery surfaces are detected, the system reduces the deceleration target to prevent traction loss. This feedback mechanism ensures that the vehicle can stop efficiently on normal surfaces while maintaining traction on slippery surfaces by adapting the deceleration profile to current conditions.
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
The system ensures deceleration comparable to engine braking while preventing excessive deceleration, maintaining vehicle stability and traction across various surfaces, enhancing drivability and safety.
Implementation Method 1
the electric motors act as generators and the electrical energy can be stored for subsequent reuse
Data Source
AI summary
The invention relates to a control system for controlling a torque generator of a vehicle. The control system is configured to receive one or more electrical signals indicative of a surface indicator; receive one or more electrical signals indicative of a deceleration demand; select a surface type from a plurality of predetermined surface types based on said one or more electrical signals indicative of a surface indicator; determine a target vehicle deceleration in dependence on the selected surface type; determine, based on said one or more electrical signals indicative of a deceleration demand, a requirement to decelerate the vehicle; and in dependence on determining said requirement, output a control signal to the torque generator. The control signal is configured to cause the torque generator to provide the target vehicle deceleration.