Work Vehicle Acceleration Control via Engine Load Feedback
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Solution Overview
Problem
Conventional control algorithms for work vehicles result in oscillations when the engine operates at or near its power limit, leading to slow acceleration, which is undesirable for consumers, especially when the power take-off (PTO) is engaged and the power supplied is unknown.
Innovation Solution
A method and system using a PID control algorithm to determine a vehicle speed error, calculate an initial acceleration command, monitor current engine load, and adjust the acceleration limit based on engine load error, ensuring stable acceleration by using a computing device to control the engine or transmission, with the final acceleration command being the lesser of the initial and calculated limits, and resetting the integral term when the speed error falls within a predetermined tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the responsiveness of the control algorithm is increased to achieve faster vehicle acceleration, then acceleration speed is improved, but oscillations occur in the acceleration when the engine operates at or near its power limit
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring engine load and using this information to adjust the acceleration command. The controller detects when the engine approaches its power limit and modifies the acceleration profile accordingly, preventing oscillations while maintaining responsiveness. This closed-loop feedback system resolves the contradiction by making the control algorithm adaptive to real-time engine conditions.
Solution Approach 2:
The patent applies dynamics by making the acceleration limit variable rather than fixed. The acceleration command is dynamically adjusted based on the engine's current load and available power margin. When the engine has excess power capacity, higher acceleration is permitted; when approaching the power limit, acceleration is reduced. This dynamic adaptation allows the system to maintain both responsiveness and stability across different operating conditions.
2Stability of the object's composition
If the responsiveness of the control algorithm is reduced to achieve stable acceleration, then oscillations are eliminated, but vehicle acceleration becomes extremely slow
Solution Approach 1:
The patent changes the parameter of acceleration limit from a fixed value to a variable that depends on engine load conditions. By calculating the available power margin (difference between maximum engine power and current power demand), the system adjusts the acceleration parameter dynamically. This allows the vehicle to accelerate rapidly when the engine has excess capacity while preventing oscillations when approaching the power limit, thus maintaining both stability and productivity.
Solution Approach 2:
The control system is made dynamic by continuously adapting the acceleration command based on real-time engine load monitoring. Rather than using a fixed responsive or non-responsive control algorithm, the system dynamically adjusts its responsiveness to match the engine's available power capacity, achieving both fast acceleration and stability.
3Device complexity
If conventional control algorithms are used to command ground speed increases, then speed control is simplified, but oscillations occur due to errors in acceleration target at or near the engine's power limit
Solution Approach 1:
The patent introduces feedback by monitoring engine load and using this information to correct acceleration target errors. The controller compares the desired acceleration with the engine's actual power capacity and adjusts the acceleration command accordingly. This feedback mechanism eliminates oscillations without requiring a fundamentally complex control algorithm, maintaining relative simplicity while achieving stability.
Solution Approach 2:
The patent uses engine load monitoring as an intermediary between the speed control command and the actual acceleration output. This intermediary measurement allows the controller to detect when the engine is approaching its power limit and adjust the acceleration profile accordingly, preventing oscillations while keeping the overall control system relatively simple.
Data Source
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AI summary
The invention is directed to a method and system for controlling acceleration of a work vehicle. It determines a vehicle speed error based on a desired speed and an actual speed of the work vehicle and calculates an initial acceleration command based on the vehicle speed error. The invention also calculates an acceleration limit via a PID control algorithm. Said limit considers an engine load error signal which corresponds to the excess load capability for the engine based on the current operating conditions. The final acceleration command corresponds to the lesser of the initial acceleration command and the acceleration limit, and the operation of the engine and/or the transmission of the work vehicle are controlled accordingly.