Creep Control for Dry Clutch Vehicles
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Solution Overview
Problem
The control of creep driving in vehicles equipped with Automated Manual Transmission (AMT) or Dual Clutch Transmission (DCT) using a dry clutch results in delays in re-acceleration and lurching due to inappropriate integral control component accumulation, especially when driving uphill or in traffic jams, where the PI controller fails to correctly reflect the integral control component and causes excessive clutch torque application.
Innovation Solution
A method where a controller determines if the transfer torque is 0 or less and the control error is non-positive, stopping the accumulation of the integral control component and reducing it over time using a forgetting factor, thereby creating a creep control signal that combines proportional and integral control components to prevent shock and lurching during creep driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple PI controller is used to control creep driving, then the control method is simple and easy to implement, but the re-acceleration performance deteriorates due to inappropriate integral control component accumulation when driving downhill or in traffic jams
Solution Approach 1:
The patent applies dynamics by making the integral control component accumulation dynamic rather than static. The controller dynamically adjusts whether to accumulate the integral control component based on real-time detection of vehicle speed relative to target creep speed and transfer torque status. When vehicle speed exceeds target creep speed and transfer torque is zero or negative, accumulation is stopped; otherwise, accumulation continues normally. This dynamic adjustment resolves the contradiction by maintaining simple PI controller structure while adapting integral accumulation behavior to driving conditions, thereby preserving re-acceleration performance.
2Stability of the object's composition
If the integral control component continues to accumulate when vehicle speed exceeds target creep speed, then the PI controller maintains continuous control action, but the vehicle experiences delays in re-acceleration when needing to climb uphill
Solution Approach 1:
The patent applies feedback by continuously monitoring vehicle speed and comparing it with target creep speed, then using this feedback information to control the accumulation of the integral control component. When vehicle speed exceeds target creep speed and transfer torque is zero or negative, the feedback mechanism stops integral accumulation, preventing excessive negative integral values that would delay re-acceleration. This feedback-based conditional accumulation maintains control signal continuity while preventing time loss during re-acceleration scenarios.
3Duration of action of stationary object
If the integral control component accumulates excessively during repeated stop-and-go in traffic jams, then the PI controller ensures continuous creep control, but the dry clutch experiences shock and lurching when creep driving is resumed
Solution Approach 1:
The patent applies preliminary anti-action by proactively stopping the accumulation of the integral control component when vehicle speed exceeds target creep speed and transfer torque is zero or negative, before excessive accumulation can occur. This preventive measure counteracts the potential harmful effect of excessive integral accumulation that would cause clutch shock and lurching upon resumption of creep driving. By anticipating and preventing the problem before it occurs, the system maintains continuous creep control during stop-and-go traffic while avoiding harmful clutch shocks.
4Reliability
If the PI controller keeps accumulating the integral control component when the dry clutch is completely disengaged, then the controller maintains control authority, but the transfer torque cannot be correctly controlled to zero
Solution Approach 1:
The patent applies dynamics by making the integral control component accumulation dynamic rather than static. The controller dynamically adjusts whether to accumulate the integral control component based on real-time detection of vehicle speed relative to target creep speed and transfer torque status. When vehicle speed exceeds target creep speed and transfer torque is zero or negative, accumulation is stopped; otherwise, accumulation continues normally. This dynamic adjustment resolves the contradiction by maintaining simple PI controller structure while adapting integral accumulation behavior to driving conditions, thereby preserving re-acceleration performance.
Data Source
AI summary
A method for controlling creep driving of a vehicle may include determining, by a controller for controlling a dry clutch, whether transfer torque of the dry clutch is 0 or less and a control error resulting from subtraction of a current car speed from a target creep speed is 0 or less, which is referred to as a step of determining condition, and stopping, by the controller, accumulation of an integral control component for creep controlling if the condition in the step of determining condition is met, which is referred to as a step of stopping accumulation.