Vehicle Velocity Set Point Adjustment for Cruise Control
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Solution Overview
Problem
Current cruise control systems often result in non-optimal velocity profiles for vehicles, leading to either unnecessarily low speeds on flat roads or excessive speeds on downhill stretches, which can result in prolonged travel times and the risk of speeding fines, causing inefficiencies and discomfort for drivers.
Innovation Solution
The method involves adjusting the velocity set points and braking set points based on actual vehicle behavior, using a shift corresponding to the offset between the set velocity and downhill speed control velocity, to create a hysteresis that allows the vehicle to maintain a speed close to the speed limit without exceeding it, thereby optimizing the velocity profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the downhill speed control velocity is set higher than the speed limit to allow faster downhill travel, then the travel time is reduced, but the vehicle may exceed the speed limit and incur speeding fines
Solution Approach 1:
The patent applies dynamics by making the velocity set point adjustable between two values based on actual vehicle behavior. The system dynamically switches between a first velocity set point (higher, closer to or exceeding speed limit) and a second velocity set point (lower, below speed limit) depending on whether the vehicle is accelerating or decelerating, allowing optimal speed selection for different driving conditions without incurring fines
Solution Approach 2:
The patent implements feedback by continuously monitoring actual vehicle behavior (acceleration/deceleration patterns) and using this information to adjust the velocity set point. The control system receives feedback about the vehicle's motion state and automatically selects the appropriate velocity set point to maintain compliance with speed limits while optimizing travel time
2Stability of the object's composition
If the cruise control system demands engine torque while the downhill speed control system simultaneously brakes the vehicle, then the regulation stability is compromised, but this counteracting behavior may occur with fixed velocity set points
Solution Approach 1:
The patent uses feedback to monitor the interaction between cruise control and downhill speed control systems. By detecting when both systems are active with conflicting demands, the system adjusts the velocity set point to prevent simultaneous opposing actions, thereby maintaining regulation stability
Solution Approach 2:
The patent applies preliminary anti-action by proactively adjusting the velocity set point to prevent the counteracting behavior from occurring. When the system detects conditions that would lead to conflicting cruise control and downhill speed control demands, it preemptively modifies the set point to avoid the instability before it occurs
Data Source
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AI summary
A method and a system for adjusting the set points for regulating the velocity of a vehicle are presented, wherein the velocity regulation is performed through the utilization of at least one cruise control and one downhill speed control. A cruise control controls an engine system with a velocity set point vref based on a selected set velocity vset. The downhill speed control controls a brake system with a braking set point vdhsc_ref based on a downhill speed control velocity vdhsc, wherein said downhill speed control velocity vdhsc is related to said set velocity vset by an offset voffset. According to the present invention, the velocity set point vref and the braking set point vdhsc_ref is adjusted by at least one shift vshift, which has a value corresponding to said offset voffset, vshift = voffset, wherein the adjustment is performed based on an actual behavior of the vehicle. As high an actual average velocity as possible is achieved hereby without the driver being at risk of being fined for speeding, which also results in as short a travel time as possible.