Dual-Motor Slip Torque Control for Low-μ Vehicle Stability
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining traveling stability on low μ road surfaces, such as frozen roads, where excessive wheel idling can lead to reduced stability and control issues.
Innovation Solution
A vehicle controlling apparatus that includes slip determining units and controllers for both front and rear wheels, which adjust motor torque to maintain predetermined slip rates and implement behavior stability control by correcting the target torque of the rear motor when the front wheel slip control is satisfied but the rear wheel slip control is not, thereby preventing excessive idling and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If motor torque is increased to improve acceleration performance, then acceleration capability is improved, but wheel idling increases on low μ road surfaces reducing traveling stability
Solution Approach 1:
The control apparatus dynamically adjusts motor torque based on detected wheel idling states and road conditions. When idling is detected, the system reduces motor torque to prevent excessive wheel spin, while maintaining acceleration capability when conditions are favorable. This parameter adjustment resolves the contradiction by adapting power output to actual road friction conditions.
Solution Approach 2:
The system continuously monitors wheel rotation speeds and detects idling states through comparison with vehicle speed. This feedback mechanism allows the control apparatus to identify when wheels are spinning excessively and automatically reduce torque accordingly, maintaining stability while preserving acceleration performance when needed.
2Stability of the object's composition
If slip control is applied to maintain predetermined slip rates, then traveling stability is improved, but wheel idling cannot be completely prevented leading to reduced control effectiveness
Solution Approach 1:
The control apparatus applies slip control in advance to prevent excessive wheel idling before it becomes severe. By detecting early signs of wheel spin and applying counteracting torque reduction, the system maintains better control effectiveness while preserving traveling stability. This preliminary action prevents the need for more aggressive corrective measures.
Solution Approach 2:
The system proactively manages wheel slip by maintaining predetermined slip rates before complete loss of control occurs. This preliminary control action ensures that wheels remain in an optimal slip range for traction, improving both stability and control reliability by preventing extreme idling conditions.
3Measurement precision
If separate slip control is applied to front and rear wheels independently, then individual wheel control precision is improved, but overall vehicle behavior stability deteriorates due to uncoordinated torque distribution
Solution Approach 1:
The control apparatus merges front and rear wheel slip controls into a coordinated system. By integrating control of both axles and adjusting torque distribution between them, the system maintains individual wheel precision while ensuring overall vehicle stability. The combined control prevents uncoordinated torque application that would cause erratic vehicle behavior.
Solution Approach 2:
The system applies different control strategies to front and rear wheels based on their specific idling conditions and positions. Front wheels may receive different torque adjustments than rear wheels depending on local slip conditions, allowing precise local control while maintaining overall vehicle stability through coordinated management of these local differences.
Data Source
AI summary
A vehicle controlling apparatus includes first and second slip determining units, first and second slip controllers, and a target torque corrector. The first slip controller is configured to maintain a slip rate of a first drive wheel at a predetermined slip rate, in a case where an execution condition of a first slip control is determined by the first slip determining unit as being satisfied. The second slip controller is configured to maintain a slip rate of a second drive wheel at a predetermined slip rate, in a case where an execution condition of a second slip control is determined by the second slip determining unit as being satisfied. The target torque corrector is configured to decrease a target torque of a second motor, in a case where the execution condition of the first slip control is satisfied and where the execution condition of the second slip control is unsatisfied.