Vehicle Control Device Uphill Driving Force Slope Adjustment
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Solution Overview
Problem
Conventional vehicle control systems may delay the start of a vehicle on an uphill slope, leading to excessive driving force and potential collision with detected objects due to inadequate adjustment of driving force generation.
Innovation Solution
A vehicle control device with an object determination unit, driving force control unit, slope calculation unit, and increase rate changing unit that adjusts the driving force command value based on the road slope, gradually increasing the driving force until a predetermined speed is reached and then lowering it, while ensuring the driving force does not exceed the driver's request, thereby moderating the actual driving force increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the driving force command value is raised in a conventional manner to ensure the vehicle starts on an uphill slope, then the vehicle can overcome the slope, but the driving force may excessively increase causing delayed stopping and potential collision with detected objects
Solution Approach 1:
The patent applies dynamics by making the driving force command value adjustable and time-dependent. The control unit dynamically modifies the driving force command value based on detected vehicle state (stationary or moving) and slope conditions, transitioning between different increase rates. This dynamic adjustment ensures adequate driving force for uphill starting while preventing excessive force buildup that would cause delayed stopping and potential collisions.
Solution Approach 2:
The patent changes the parameter of driving force command value based on vehicle state and slope conditions. When the vehicle is stationary on an uphill slope, a first increase rate is applied to ensure sufficient force for starting. Once the vehicle starts moving, a second increase rate (lower than the first) is applied to moderate the driving force increase. This parameter change resolves the contradiction by adapting the driving force to the current operational phase.
2Speed
If the driving force is increased rapidly to overcome uphill slope resistance, then the vehicle can start moving, but the start time is delayed and the vehicle may reach the detected object
Solution Approach 1:
The patent applies preliminary action by pre-establishing different increase rate strategies based on predicted vehicle state. The control unit is programmed to switch from a higher increase rate (when stationary) to a lower increase rate (when moving) before the vehicle actually reaches problematic speeds. This preliminary differentiation of increase rates ensures rapid enough starting while preventing excessive force accumulation that would cause delayed stopping.
3Reliability
If the driving force command value is lowered after vehicle start to prevent collision, then collision risk is reduced, but the vehicle may not have sufficient driving force to start on uphill slopes
Solution Approach 1:
The patent applies segmentation by dividing the driving force control into distinct phases: a first phase when the vehicle is stationary with a first increase rate, and a second phase when the vehicle is moving with a second increase rate. This segmentation allows the system to provide sufficient driving force for uphill starting in the first phase while ensuring collision avoidance in the second phase, resolving the contradiction between these two requirements.
Data Source
AI summary
A vehicle control ECU is configured to determine the presence or absence of an object ahead of a vehicle in its traveling direction. The vehicle control ECU is configured to, if an object has been detected, raise a driving force command value in the vehicle in a stepwise manner such that the driving force command value does not exceed a request value determined based on an accelerator position designated by a driver until the speed of the vehicle reaches a predetermined speed, and lower the driving force command value after the speed of the vehicle reaches the predetermined speed. The vehicle control ECU is configured to calculate the slope of a road on which the vehicle runs. The vehicle control ECU is configured to change the increase rate per time for raising the driving force command value based on the slope.