Vehicle Driving Assist Apparatus Turning Radius Control
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Solution Overview
Problem
Conventional driving assist apparatuses for vehicles experience a strong deceleration feeling when performing turning assist control in a locked center differential state, leading to discomfort for the driver, as the rotational speed of the front wheels decreases with the rear wheels during extremely low-speed traveling.
Innovation Solution
A driving assist apparatus that adjusts the target wheel speeds and braking forces for each wheel to maintain the rotational speed of the front and rear wheels before and after turning assist control, ensuring the vehicle can turn with a smaller radius without significant deceleration, by setting the target wheel speed of the inside rear wheel to zero and adjusting the speeds of other wheels to maintain the predetermined ratio and vehicle body speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If turning assist control is performed in locked center differential state, then turning radius is reduced, but strong deceleration feeling occurs to driver
Solution Approach 1:
The control device changes the target wheel speed parameters dynamically based on the center differential state. When locked state is detected, it adjusts target wheel speeds to maintain rotational speed consistency, preventing the deceleration feeling while still enabling tight turning through differential braking of individual wheels
Solution Approach 2:
The control device continuously monitors the actual wheel speeds and compares them with target wheel speeds, adjusting braking forces in real-time to maintain the desired rotational speed relationship between front and rear wheels, thereby eliminating the deceleration sensation
Data Source
AI summary
This driving assist apparatus for a vehicle sets target wheel speed of an inside rear wheel in turning to substantially zero when a state of a center differential apparatus is a locked state in a case where the vehicle is turned in an extremely low speed traveling control. Further, the apparatus sets target wheel speed of each of wheels other than the inside rear wheel in turning such that a mean value of target wheel speeds of front wheels is equal to a mean value of target wheel speeds of rear wheels and the mean value of target wheel speeds of front wheels is equal to target vehicle body speed. Furthermore, the apparatus adjusts driving force and braking force such that wheel speed of each of the wheels becomes equal to the target wheel speed set for each of the wheels.