Dual Torque Control for Vehicle Stability and Energy Efficiency
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Solution Overview
Problem
Existing methods for operating motor vehicles with two drives do not adequately ensure stabilization, particularly during specific situations like turning or improving traction, which affects driving behavior and stability.
Innovation Solution
A method involving two control devices, where the first control device predetermines a family of partial torque combinations for individual drives and sends data signals to a second control device, which selects and restricts these combinations based on additional stability-related variables like yaw rate and acceleration, to ensure vehicle stability by defining a restricted torque bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If torque distribution is optimized for energy efficiency using a single control device, then energy consumption is reduced, but vehicle stability during dynamic situations deteriorates
Solution Approach 1:
The control system is divided into two independent control devices: a first control device that optimizes torque distribution for energy efficiency, and a second control device that ensures vehicle stability during dynamic situations. Each control device operates independently with its own control logic, allowing simultaneous optimization of energy efficiency and stability without compromise.
Solution Approach 2:
The two control devices communicate through an interface that exchanges torque demand signals and stability status information. This intermediary communication allows the control devices to coordinate their actions, ensuring that energy-efficient torque distribution does not compromise vehicle stability while maintaining independent optimization capabilities.
2Device complexity
If a single control device manages both energy efficiency and stability, then device complexity is reduced, but control precision for stability deteriorates
Solution Approach 1:
The control functions are segmented into two specialized control devices: one dedicated to energy-efficient torque distribution and another dedicated to stability control. This segmentation allows each device to focus on its specific function with high precision, using specialized sensors and control algorithms optimized for its particular purpose.
Solution Approach 2:
Each control device is equipped with specific sensors and control logic tailored to its function. The stability control device receives dedicated inputs from yaw rate sensors, lateral acceleration sensors, and steering angle sensors, allowing it to make precise stability decisions without being diluted by general-purpose control logic.
3Ease of operation
If torque allocation follows fixed criteria, then ease of operation is improved, but adaptability to different driving situations deteriorates
Solution Approach 1:
The control system dynamically adapts torque distribution based on real-time driving conditions. The stability control device continuously monitors yaw rate, lateral acceleration, and steering angle to detect dynamic situations, automatically adjusting torque allocation to maintain stability while the first control device continues to optimize for energy efficiency under varying conditions.
Solution Approach 2:
The system changes operational parameters based on detected driving situations. During normal driving, the first control device dominates torque distribution for energy efficiency. During detected dynamic situations (high yaw rate, high lateral acceleration, large steering angles), the second control device restricts torque bandwidth and adjusts distribution to prioritize stability, seamlessly adapting to different operating conditions.
Data Source
AI summary
In a motor vehicle having two, in particular electrical, drives, a partial torque is in each case intended to be assigned to the individual drives from a demanded total torque, to be precise taking account of the energy efficiency on the one hand and the stability of the vehicle on the other hand. A first controller is responsible for taking account of the energy efficiency, and predetermines a bandwidth of possible partial torques for an individual drive. This bandwidth may be restricted by a second controller, when driving stability requires this. The second controller is coupled to appropriate sensors (yaw rate sensor, lateral acceleration sensor, longitudinal acceleration sensor) and knows the steering angle φ. In the course of interchanging data signals with a first control device, the partial torques are defined with the involvement of the second control device, for which purpose the first control device emits control commands.