Vehicle Drive Force Control Using Pedal Speed-Corrected Acceleration
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Solution Overview
Problem
Existing vehicle control systems fail to accurately control acceleration in response to accelerator pedal operations, leading to uncomfortable jerks and inaccurate acceleration changes, especially when the pedal is operated frequently, due to uniform target acceleration calculations and abrupt changes around zero acceleration.
Innovation Solution
A driving force control system that calculates a corrected target acceleration by adding an acceleration enrichment value to the basic target acceleration, based on the position and speed of the accelerator pedal, and the intended acceleration required by the driver, using a predetermined control gain that adjusts dynamically with pedal speed and road grade, ensuring smooth acceleration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the target acceleration is corrected by multiplying with a gain greater than 1 when accelerator pedal operating speed is fast, then the desired acceleration is enhanced, but the target acceleration is determined uniformly based on accelerator pedal position and vehicle speed, causing inaccurate acceleration assessment and stepwise changes around zero acceleration
Solution Approach 1:
The patent introduces a new parameter 'accelerator pedal operating speed' (derivative of pedal position) to dynamically adjust the target acceleration calculation. When the operating speed exceeds a threshold, the system switches to a corrected calculation mode that accounts for the rapid pedal movement, thereby improving acceleration accuracy without causing stepwise changes. This resolves the contradiction by changing the calculation parameters based on pedal operation characteristics.
2Ease of operation
If the corrected target acceleration is reduced to initial value when acceleration is reduced to zero, then the control returns to normal, but the jerk of acceleration changes within acceleration range around zero, causing uncomfortable feelings and frequent unnecessary pedal operations
Solution Approach 1:
The patent applies preliminary action by reducing the corrected target acceleration to the initial value before the actual acceleration reaches zero. Specifically, when the calculated acceleration falls within a predetermined range around zero (not exactly at zero), the system proactively terminates the correction mode. This prevents the abrupt jerk that would occur at zero acceleration and eliminates unnecessary pedal operations, resolving the contradiction between smoothness and stability.
Data Source
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AI summary
A drive force control system controls acceleration of a vehicle (Ve) accurately in line with an operation of an accelerator pedal (4) to improve an acceleration feel. A controller (7) calculates a corrected target acceleration (Gh) when a required acceleration (G) is large and an operating speed of the accelerator pedal (4) is fast, and converts the corrected target acceleration (Gh) into a target driving force to propel the vehicle (Ve) so as to achieve the corrected target acceleration (Gh) by generating the target driving force.