Autonomous Vehicle Drive Mode Selection for Off-Road Control
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Solution Overview
Problem
Autonomous vehicles face challenges in effectively controlling vehicle speed, engine speed, and transmission gear ratio, particularly in off-road conditions where maintaining desired speeds and gear ratios is crucial for efficient operation and implement functionality.
Innovation Solution
A control system that selects from multiple operating modes to manage vehicle speed and transmission gear ratios, including modes for maintaining desired speeds and engine speeds while adjusting gear ratios, ensuring optimal performance on various terrains and with coupled implements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single control mode is used for all operating conditions, then the control system is simple, but the vehicle cannot maintain optimal performance across different terrains and implement configurations
Solution Approach 1:
The control system dynamically switches between multiple operating modes (first mode through fourth mode) based on detected conditions such as implement coupling, terrain type, and vehicle speed. This allows the system to adapt its control strategy in real-time without requiring a completely complex redesign, as each mode has a specific control approach optimized for certain conditions
Solution Approach 2:
The control system is designed to perform multiple functions by incorporating different control modes that can handle various operating scenarios. The same control system architecture manages both speed control and gear ratio control, and can operate with or without implements coupled to the power takeoff shaft, making it universally applicable across different conditions
2Measurement precision
If the system maintains both vehicle speed and engine speed simultaneously, then operational precision is improved, but the control complexity increases
Solution Approach 1:
The control system segments the control task into distinct modes where different parameters are prioritized. In the third mode, the system specifically maintains both vehicle speed and engine speed simultaneously by independently controlling the transmission gear ratio and engine throttle. This segmentation allows complex dual-parameter control to be managed through structured mode-specific logic rather than a monolithic control algorithm
Solution Approach 2:
The control system uses feedback from vehicle speed sensors and engine speed sensors to continuously monitor actual performance against desired setpoints. In modes where both speeds are maintained, the system adjusts transmission and engine controls based on feedback signals, enabling precise dual-parameter control through closed-loop regulation
3Speed
If the transmission gear ratio is frequently adjusted to maintain vehicle speed, then speed control is improved, but gear slippage and mechanical wear increase
Solution Approach 1:
The control system dynamically selects appropriate gear ratios based on operating conditions and vehicle speed requirements. By using multiple operating modes with different control strategies, the system can maintain vehicle speed through engine control in some modes, reducing the frequency of transmission gear changes and associated mechanical stress
Solution Approach 2:
The control system acts as an intermediary that coordinates between engine control and transmission control. By managing both systems together in a coordinated manner, the system can achieve speed control while minimizing abrupt gear changes, thereby reducing mechanical wear and improving transmission reliability
Data Source
AI summary
A method for controlling an off-road vehicle includes selecting an operating mode from a plurality of candidate operating modes. The plurality of candidate operating modes includes a first operating mode that includes substantially maintaining a first desired vehicle speed of the off-road vehicle; a second operating mode that includes substantially maintaining a first desired gear ratio of the transmission and substantially maintaining a first desired engine speed of the engine; a third operating mode that includes substantially maintaining a second desired vehicle speed of the off-road vehicle and substantially maintaining a second desired engine speed of the engine; and a fourth operating mode that includes substantially maintaining a third desired gear ratio of the transmission and substantially maintaining a third desired vehicle speed of the off-road vehicle.