Vehicle Speed Control System Seamless Mode Transition
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Solution Overview
Problem
Existing vehicle speed control systems are ineffective at low speeds and in off-road conditions, as they often require minimum speed thresholds and are disabled by wheel slip events, leading to increased driver workload and reduced vehicle composure.
Innovation Solution
A vehicle control system that allows seamless transition between different speed control modes, such as low-speed progress control and hill descent control, by setting target speeds based on the current speed of the previous system, ensuring smooth acceleration and maintaining traction on varied terrain without sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a minimum speed threshold is imposed on cruise control systems to reduce low speed collision risk, then safety is improved, but the system becomes ineffective in low speed and off-road conditions
Solution Approach 1:
The speed control system is segmented into multiple independent control systems, each with its own minimum speed threshold. The first speed control system (cruise control) has a higher minimum threshold for highway safety, while the second speed control system (off-road control) has a lower minimum threshold for off-road and low-speed operation. This segmentation allows each system to be optimized for its specific operating conditions without compromising overall system versatility.
Solution Approach 2:
The system dynamically switches between different speed control systems based on operating conditions. The controller automatically selects which speed control system to activate depending on whether the vehicle is operating in highway conditions or off-road/low-speed conditions, allowing the minimum speed threshold to adapt to the current operating environment rather than being fixed.
2Reliability
If cruise control systems are disabled upon detecting wheel slip events, then traction control effectiveness is improved, but vehicle progress is interrupted in off-road conditions where wheel slip is common
Solution Approach 1:
The control system is segmented into multiple speed control systems with different responses to wheel slip events. The first speed control system disables upon wheel slip detection to maintain traction control effectiveness, while the second speed control system continues operating despite wheel slip events to maintain vehicle progress in off-road conditions. This segmentation allows each subsystem to fulfill its specific function without compromising the other.
Solution Approach 2:
The controller acts as an intermediary that manages the interaction between multiple speed control systems. When wheel slip is detected, the controller determines which speed control system should remain active based on current operating conditions, allowing the system to maintain both traction control effectiveness and vehicle progress continuity through coordinated management of multiple control systems.
3Device complexity
If the target speed of a newly selected speed control system is set to the current vehicle speed, then system simplicity is improved, but sudden speed changes occur during transitions between systems
Solution Approach 1:
Before the speed control system transition is completed, the controller preliminarily determines the appropriate target speed for the newly selected system by considering the current vehicle speed and the target speed of the previously active system. This preliminary action ensures that the target speed is set appropriately in advance, preventing sudden speed changes and maintaining vehicle composure during the transition.
Solution Approach 2:
The system uses feedback from the currently active speed control system's target speed setting to inform the initialization of the newly selected speed control system. The controller monitors the target speed of the active system and uses this information to set an appropriate initial target speed for the new system, ensuring smooth transitions and maintaining vehicle stability.
Data Source
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AI summary
Embodiments of the present invention provide a vehicle control system comprising a plurality of speed control systems each operable to cause the vehicle to operate in accordance with a respective target speed, the system being operable wherein one of said plurality of speed control systems may be selected to control vehicle speed at a given moment in time, wherein when responsibility for speed control is transferred from a first one of the plurality of speed control systems to a second one of the speed control systems, the second one of the speed control systems is operable to set a value of target speed thereof to a value corresponding to that of the target speed of the first.