Loader Implement Self-Leveling With Rollback Prevention Control
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Solution Overview
Problem
Conventional work vehicles struggle with maintaining the implement at a constant angular position relative to the vehicle's driving surface due to poor system responsiveness and imprecise control, particularly at the upper end of the loader arm movement range, leading to materials being inadvertently dumped.
Innovation Solution
A computing system is used to implement closed-loop control algorithms that transition between feed-forward control and closed-loop position or velocity control based on the sign of the implement angle error, adjusting the implement angle using hydraulic valves to maintain a desired orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional automatic control systems are used to maintain constant implement position, then operator workload is reduced, but system responsiveness and control precision deteriorate especially at upper loader arm positions
Solution Approach 1:
The control system dynamically transitions between feed-forward control and closed-loop control modes based on the loader arm position. At lower positions where feed-forward control is sufficient, the system operates in open-loop mode. At upper positions where precision is critical, the system automatically engages closed-loop control with feedback from implement angle sensors, thereby maintaining precision where needed while keeping the system simple where possible.
Solution Approach 2:
The system incorporates feedback control mechanisms that actively monitor implement angle using sensors and adjust control commands accordingly. The feedback loop compares the actual implement angle with the desired angle and generates corrective commands to maintain precision, particularly when operating at upper loader arm positions where control accuracy is most challenging.
2Device complexity
If feed-forward control is used to simplify the control system, then device complexity is reduced, but system responsiveness and implement position control precision worsen
Solution Approach 1:
The control system is designed to dynamically adapt its complexity based on operating conditions. It uses feed-forward control for basic operation to maintain simplicity, but automatically transitions to closed-loop feedback control when reliability requirements increase, such as when the loader arm is in upper positions or when precise implement positioning is critical for the current task.
Solution Approach 2:
The system changes control parameters based on loader arm position and operational context. The control algorithm adjusts gain values, transition thresholds, and control mode selection based on real-time parameters such as arm angle, implement angle, and operator inputs, thereby optimizing the balance between complexity and reliability for each specific operating condition.
3Measurement precision
If manual implement adjustment is used to achieve precise positioning, then control precision is improved, but operator workload and time consumption increase
Solution Approach 1:
The control system performs self-adjustment through automatic closed-loop control, eliminating the need for continuous manual intervention. The system monitors implement angle continuously and automatically generates corrective commands to maintain desired positioning, thereby achieving precision comparable to manual control without the time loss associated with constant operator adjustment.
Solution Approach 2:
Real-time feedback from implement angle sensors enables the system to detect positioning deviations and automatically correct them. This closed-loop feedback mechanism maintains high precision by continuously comparing actual position with desired position and applying corrective control actions, replicating and improving upon manual control precision while eliminating operator time consumption.
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
The system provides precise and stable implement positioning, preventing rollback and dump conditions, ensuring materials are retained during loader arm movements.
Implementation Method 1
controlling an operation of the hydraulic valve associated with the implement based at least in part on the closed-loop valve command signal to adjust the implement angle back towards the target implement angle
Data Source
AI summary
A method for automatically adjusting the position of an implement of a lift assembly of a work vehicle includes receiving an input associated with raising a boom of the lift assembly relative to the ground, monitoring an implement angle relative to a target implement angle as the boom is being raised, and identifying an implement angle error relative to the target implement angle as the boom is moved following the target implement angle initially being reached. In addition, the method includes selecting a closed-loop control algorithm to control movement of the implement based at least in part on a sign of the implement angle error, wherein the closed-loop control algorithm corresponds to a closed-loop position control algorithm when the implement angle error is a positive implement angle error and a closed-loop velocity control algorithm when the implement angle error is a negative implement angle error.