Vehicle Driving System Torque Control for Stability
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Solution Overview
Problem
The existing vehicle driving system lacks a clear method for controlling the first and second motors when shifting from a brake-applied state to a brake-released state, which can lead to worsened running stability unless the motors are accurately controlled.
Innovation Solution
A vehicle driving system with a motor controller that controls the first and second motors to maintain a torque sum approaching zero while maintaining a torque difference between them, using a rotation restricting unit that can be shifted between applied and released states, and determining target rotation states based on motor efficiency and electric power supply efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the brake units are released from the applied state without specific motor control, then the vehicle can transition from start assist to normal operation, but the running stability of the vehicle is worsened
Solution Approach 1:
The motor controller performs preliminary control actions before and during the brake release process. It calculates target rotation state quantities for both motors in advance, and gradually transitions the torque sum from a non-zero state to zero while maintaining the torque difference, ensuring stability is preserved throughout the transition rather than allowing abrupt changes
Solution Approach 2:
The control system dynamically adjusts motor parameters during the transition. The torque sum is controlled to gradually decrease towards zero rather than changing abruptly, and the controller continuously monitors and adjusts rotation state quantities based on real-time conditions, making the system adaptive during the critical brake release phase
2Speed
If the torque sum of the first and second motors is quickly reduced to zero when releasing the brake units, then the transition to normal operation is faster, but the vehicle experiences quick changes in torque which worsen running stability
Solution Approach 1:
The control system dynamically adjusts motor parameters during the transition. The torque sum is controlled to gradually decrease towards zero rather than changing abruptly, and the controller continuously monitors and adjusts rotation state quantities based on real-time conditions, making the system adaptive during the critical brake release phase
Solution Approach 2:
The torque sum is controlled to gradually decrease towards zero in a staged manner rather than instantaneously. This periodic or progressive reduction allows the system to transition smoothly through intermediate states, preventing sudden torque changes that would destabilize the vehicle while still achieving the zero torque sum target
3Stability of the object's composition
If the first and second motors are controlled to maintain torque difference while reducing torque sum to zero, then the running stability is improved, but the control complexity increases
Solution Approach 1:
The control objectives are segmented into two independent components: torque sum control and torque difference control. The motor controller separately calculates and manages these two parameters, allowing each to be optimized independently while working together to achieve stable operation during brake release
Solution Approach 2:
The control system changes key parameters (torque sum and torque difference) in a coordinated manner. By controlling the torque sum to gradually decrease to zero while maintaining the torque difference, the system transforms the motor output parameters to achieve stability without requiring complex mechanical modifications
Data Source
AI summary
A vehicle driving system includes: a left wheel driving system having a first motor and a first speed changer; a right wheel driving system having a second motor and a second speed changer; a motor controller which controls the first motor and the second motor, a rotation restricting unit which can be shifted between a released state and an applied state; and a rotation restricting unit controller which controls the rotation restricting unit. When the rotation restricting unit controller shifts the rotation restricting unit from the applied state to the released state, the motor controller controls the first motor and the second motor so that a torque sum of the first motor and the second motor approaches zero while maintaining a torque difference between the first motor and the second motor.