Vehicle Torque Control Using Drive Shaft Torsion Feedback
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Solution Overview
Problem
Conventional methods for controlling vehicle torque based on accelerator opening lead to body vibrations due to drive shaft torsion and gear backlash, which degrade acceleration and deceleration performance by reducing transient response.
Innovation Solution
A control device and method that sets the target torsion angle of the drive shaft based on accelerator opening, adjusting the target torque of the drive source to consider the behavior of the drive shaft during acceleration or deceleration, including feedback control to match the actual torsion angle and reduce gear backlash quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the target torque is directly controlled based on accelerator opening, then the transient response during acceleration or deceleration is improved, but body vibrations occur due to drive shaft torsion and gear backlash
Solution Approach 1:
The controller calculates the target torsion angle in advance based on the accelerator opening, and determines the target torque considering the drive shaft's torsional behavior before actual acceleration or deceleration occurs. This preliminary calculation allows the system to anticipate and compensate for torsional vibrations, reducing body vibrations while maintaining good transient response.
Solution Approach 2:
The controller uses feedback from the actual torsion angle (calculated from angular velocity difference between drive source and wheel) to correct the target torque. This feedback mechanism allows the system to adjust the torque command in real-time based on actual drive shaft behavior, effectively suppressing body vibrations while responding to accelerator input.
2Object-affected harmful factors
If processing is performed to dampen changes in target torque during acceleration or deceleration, then body vibrations are suppressed, but the transient response reduces and acceleration performance degrades
Solution Approach 1:
Instead of directly damping the target torque changes, the controller changes the parameter to target torsion angle and calculates target torque based on the relationship between torsion angle and angular velocity. This parameter transformation allows the system to suppress vibrations through physical laws rather than artificial damping, maintaining transient response performance.
Solution Approach 2:
The controller performs preliminary calculation of target torque using the formula that incorporates both torsion angle and angular velocity. This pre-calculation approach determines the optimal torque command before execution, suppressing vibrations through inherent system dynamics rather than post-hoc damping, thus preserving transient response.
3Object-affected harmful factors
If the target torque is adjusted to consider drive shaft behavior, then body vibrations are suppressed, but the device complexity increases due to additional control calculations
Solution Approach 1:
The controller utilizes existing sensor data (angular velocity from drive source and wheel speed sensors) to calculate the actual torsion angle without requiring additional sensors or complex measurement systems. The system serves itself by using readily available information to compute torsion and adjust torque, minimizing additional hardware complexity while achieving vibration suppression.
Data Source
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AI summary
To provide a control device for a vehicle capable of controlling the torque of a drive source so as to appropriately balance the suppression of body vibrations and the securing of a transient response during acceleration or deceleration. This control device for a vehicle includes an accelerator position sensor 30 that detects the accelerator opening, a torque adjustment mechanism such as a throttle valve 5 that adjusts the torque of an engine 10 as the drive source of the vehicle, and a PCM 50 that controls the torque adjustment mechanism based on the accelerator opening. The PCM 50 sets the target acceleration of the vehicle based on the accelerator opening, sets the target torsion angle of the drive shaft 209 based on the target acceleration, sets the target torque of the engine 10 based on the target torsion, and controls the torque adjustment mechanism based on the target torque.