Vehicle Speed Control via Pitch-Adjusted Torque Distribution
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Solution Overview
Problem
Off-road vehicles face challenges in maintaining control and speed while navigating rocky terrain due to pitching and rolling, which requires significant driver effort and can result in getting stuck.
Innovation Solution
A driveline operating method that adjusts vehicle speed based on pitch and roll angles, using a controller to maintain a requested speed by modifying torque distribution between axles and accounting for gravitational influences, thereby improving speed control and terrain negotiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vehicle speed is reduced to zero to maintain position on rocks, then the vehicle can maintain its position, but it becomes difficult to maintain position and requires significant driver effort
Solution Approach 1:
The vehicle's control system automatically adjusts requested speed based on pitch sensor data without requiring driver intervention. The system serves itself by detecting pitch changes and autonomously modifying speed commands to maintain position stability, eliminating the need for constant driver effort to compensate for terrain variations.
Solution Approach 2:
The system uses pitch sensors to continuously monitor vehicle orientation and feeds this information back to the controller. The controller then adjusts the requested speed based on the pitch value, creating a closed-loop feedback system that automatically maintains vehicle position stability on rocky terrain without requiring driver input.
2Speed
If the vehicle maintains a slow speed while crawling over rocks, then the vehicle can negotiate terrain, but it requires significant driver effort to maintain requested speed
Solution Approach 1:
The control system automatically compensates for pitch-induced speed variations without driver intervention. By detecting pitch changes and autonomously adjusting the requested speed, the system maintains the desired slow crawling speed while eliminating the need for driver effort to counteract gravitational effects on speed.
Solution Approach 2:
The system dynamically changes the requested speed parameter based on pitch sensor readings. When pitch indicates the vehicle is rolling or pitching, the controller modifies the speed command to compensate, allowing the vehicle to maintain consistent slow speed crawling over rocks without requiring driver input to adjust for terrain-induced speed variations.
3Stability of the object's composition
If the vehicle operates in speed control mode over rocks, then the vehicle can maintain requested speed, but pitch and roll make speed control difficult
Solution Approach 1:
Pitch and roll sensors serve as intermediaries between the physical terrain disturbances and the control system. These sensors detect pitch and roll angles, converting complex mechanical disturbances into measurable electrical signals that the controller can process. The controller then uses this intermediary data to adjust speed commands, bridging the gap between terrain-induced pitch/roll and speed control stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances vehicle speed control and ability to navigate difficult terrain, reducing the effort required to traverse rocky surfaces and improving exit from stuck conditions.
Implementation Method 1
adjusting the requested speed via the controller according to a value of vehicle pitch... when gravity acting on the vehicle in the vehicle's present orientation tends to increase vehicle speed in a forward direction of vehicle travel... when gravity acting on the vehicle in the vehicle's present orientation tends to decrease vehicle speed
Data Source
AI summary
Methods and systems for operating a driveline that includes one or more electric machine providing torque to one or more axles are described. In one example, a requested vehicle speed is adjusted responsive to at least one of vehicle yaw, vehicle roll, and vehicle pitch so that vehicle speed may be maintained at a requested value.