Torque Shaping Controller for Driveline Lash Mitigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Audible and tactile disturbances occur in vehicle drivelines during transient torque events due to lash in mechanical couplings, leading to longitudinal acceleration and driveline disturbances, which existing technologies fail to effectively mitigate.
Innovation Solution
A vehicle system with upstream and downstream actuators and a controller that calculates and commands shaped wheel torque commands, reducing torque to the minimum of the previous torque magnitude and estimated current torque when driver-demanded torque changes from higher to lower, to manage these disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque commands are transmitted directly without shaping, then responsiveness to driver demand is improved, but driveline disturbances and audible/tactile events occur due to lash in mechanical couplings
Solution Approach 1:
The controller performs preliminary action by shaping the torque command in advance before it reaches the actuators. When a step change in torque demand is detected, the controller proactively adjusts the torque command to limit the rate of change, preventing driveline disturbances caused by lash in mechanical couplings while still delivering the required torque change.
Solution Approach 2:
The torque shaping control dynamically adjusts the torque command based on real-time conditions. The controller continuously monitors torque demand changes and adaptively modifies the commanded torque to maintain smooth driveline operation, transitioning between different torque delivery rates as needed to balance responsiveness and disturbance mitigation.
2Stability of the object's composition
If torque shaping is applied to mitigate driveline disturbances, then driveline smoothness is improved, but torque delivery precision may be reduced
Solution Approach 1:
The controller changes parameters by adjusting the rate of torque delivery based on detected step changes in torque demand. When a step change is identified, the controller modifies the torque command parameters to limit the rate of change, thereby smoothing driveline operation while maintaining accurate delivery of the final torque target through precise control of the adjustment rate.
Solution Approach 2:
The torque shaping control uses feedback by continuously monitoring the torque demand signal for step changes and adjusting the commanded torque accordingly. The controller detects when the driver demands a sudden change in torque and uses this feedback to proactively shape the torque command, ensuring smooth driveline operation while maintaining responsiveness to driver intent.
Data Source
AI summary
A vehicle includes controller programmed to receive a driver-demanded wheel torque command and calculate a shaped wheel torque command based on the driver-demanded wheel torque command. The controller is further programmed to, in response to the driver-demanded wheel torque command changing from a first magnitude that is greater than an estimated wheel torque at a last time step to a second magnitude that is less than the estimated wheel torque at a current time step, set the shaped wheel torque to a minimum of a magnitude of the shaped wheel torque at the last time step and an estimated wheel torque at the current time step. The controller is also programmed to command the first and second actuators to produce the shaped wheel torque.