Vehicle Speed Control System for Off-Road Terrain
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Solution Overview
Problem
Automatic transmissions struggle to allow precise control of vehicle speed during off-road driving, requiring both throttle and braking inputs from the driver to maintain constant speed over obstacles, which can be challenging due to the lack of low gear ratios and inability to override preset speeds.
Innovation Solution
A system and method that uses a selec-speed control system to determine a target speed based on driver input, controlling engine torque and brake pressure to maintain the desired speed, allowing driver override and adjusting for incline and terrain, utilizing a controller that communicates with engine and brake systems to modulate torque and braking independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driver operated dial with preset speeds is used, then the vehicle can maintain constant speed over obstacles, but the driver loses the ability to control speed using throttle and brake pedals
Solution Approach 1:
The system continuously monitors vehicle speed, throttle position, and brake input to dynamically adjust engine torque and braking force. This closed-loop feedback mechanism maintains constant speed while allowing driver override through pedal inputs, resolving the contradiction between automated speed maintenance and driver control capability
Solution Approach 2:
The system dynamically adjusts the balance between automated speed control and driver input by detecting throttle and brake pedal positions. When pedals are neutral, the system maintains preset speed; when pedals are actuated, the system transitions to driver-controlled mode, providing adaptive behavior that satisfies both reliability and ease of operation requirements
2Power
If low gear ratios are used in manual transmission, then the vehicle can climb obstacles with little throttle, but the driver must manually shift gears and the system lacks adaptability to terrain
Solution Approach 1:
The system changes engine torque output parameters dynamically based on detected terrain conditions, vehicle speed, and driver input. By electronically controlling torque delivery across a wide range rather than relying on fixed gear ratios, the system achieves both the high torque needed for obstacle climbing and the adaptability to varying terrain conditions
Solution Approach 2:
The system replaces the mechanical gear shifting mechanism with an electronic control system that manipulates engine torque and braking. This substitution eliminates the need for manual gear shifts while providing continuous torque adjustment capability that adapts to different terrain conditions, resolving the contradiction between power delivery and terrain adaptability
3Reliability
If both throttle and braking are required to maintain constant speed, then the vehicle can navigate obstacles, but the driver experience becomes challenging and complex
Solution Approach 1:
The system performs self-service by automatically coordinating throttle and brake applications to maintain constant speed. The electronic control unit independently manages engine torque and braking force based on speed deviations, eliminating the need for the driver to manually coordinate both controls and significantly reducing driver effort while maintaining reliable speed control
Data Source
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AI summary
A system and method of operating a vehicle at a driver selected target speed. The system and method configured to identify a target speed based on a position of a gear shift selector and control engine torque and brake pressure to control the vehicle to operate at the target speed. The system and method is further provides manipulating the engine torque and brake pressure of the vehicle in response to a driver's throttle and brake commands to operate at a speed desired by the driver.