Drive Force Control System Torque Optimization
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Solution Overview
Problem
Existing drive force control systems for vehicles with individually connected motors to each drive wheel suffer from inefficiencies due to excessive slip between wheels and the road, leading to increased power loss and reduced acceleration, as they operate motors either as prime movers or generators inflexibly based on road conditions and torque capacity.
Innovation Solution
A drive force control system that includes a controller to manage the output torques of two motors connected to opposite drive wheels, ensuring their combined torque equals the required torque while optimizing power efficiency by adjusting torque transmission capacity and motor operation based on wheel speed and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If one pair of wheels establishes drive force and the other pair establishes brake force, then the drive force control system can control vehicle propulsion, but a large slip amount occurs between the road surface and drive wheels causing power loss and reduced acceleration
Solution Approach 1:
The system dynamically adjusts the torque transmitting capacity of the clutch based on vehicle acceleration requirements. When acceleration is insufficient, the clutch torque capacity is reduced to allow differential rotation between motors, enabling both drive wheels to contribute to propulsion rather than one braking, thereby reducing power loss and improving acceleration efficiency
Solution Approach 2:
The control system changes the torque transmitting capacity parameter of the clutch from a fixed value to a variable parameter that is adjusted based on detected acceleration. This allows the system to optimize the torque distribution between motors dynamically, preventing excessive slip and power loss while maintaining effective drive force control
2Measurement precision
If the vehicle is propelled by the output power of a single motor, then the motor can generate a large torque and operate at an optimum operating point, but the motor is less efficiently operated for generating a larger torque not smaller than a predetermined torque
Solution Approach 1:
The system enables both motors to function as prime movers simultaneously by adjusting the clutch torque capacity, allowing the vehicle to utilize the output power of both motors for propulsion. This multi-functional operation ensures that each motor operates within its efficient torque range, improving overall energy efficiency while maintaining the ability to generate large total torque
Solution Approach 2:
The clutch torque capacity is dynamically adjusted to enable flexible operation modes: single motor operation when torque requirements are low, and dual motor operation when torque requirements are high. This dynamic adaptation ensures optimal energy efficiency across the entire torque range while maintaining the ability to generate large torque when needed
3Device complexity
If the torque transmitting capacity of the clutch is inflexibly determined, then the control system is simple, but the vehicle cannot be propelled in an efficient manner under varying road conditions and torque requirements
Solution Approach 1:
The system changes the torque transmitting capacity parameter of the clutch from a fixed value to a variable parameter that is adjusted based on detected acceleration and torque requirements. This parameter change enables the system to adapt to varying road conditions and torque requirements, improving propulsion efficiency while adding only minimal control complexity through acceleration-based feedback
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 approach minimizes power loss and enhances overall efficiency by ensuring motors operate at optimal efficiency, reducing wear on drive wheels and improving vehicle acceleration by dynamically adjusting torque distribution and motor operation.
Implementation Method 1
a friction clutch is provided to enable a torque to be transmitted between these motors. The friction clutch has a torque transmitting capacity controlled depending on a road condition
Data Source
AI summary
A drive force control system appropriately controls motors each connected to a corresponding one of drive wheels, so that a vehicle can be propelled with high efficiency. First motor and second motors are controlled in such a manner that a sum of torques transmitted to a right front wheel and a left rear wheel equals to a total value of required torques of the right front wheel and the left rear wheel. A target torque of the first motor and a target torque of the second motor achieving a smallest amount of power output from an electrical power source, for the output torques from the first motor and the second motor are calculated. A torque is generated by the first motor based on the target torque of the first motor calculated, and a torque is generated by the second motor based on the target torque of the second motor calculated.