Lift Assembly Self-Leveling Control Across Nonlinear Boom Travel
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Solution Overview
Problem
Conventional automatic control systems for work vehicles fail to maintain a constant angular position of the implement relative to the vehicle's driving surface due to poor responsiveness and imprecision, particularly when accommodating the non-linearity of the lift assembly's operational dynamics.
Innovation Solution
A closed-loop control system that determines a tilt transition boom angle and generates a valve command signal to control the movement of the implement, using a combination of feed-forward and feedback control to maintain the implement at a target angle as the boom is moved across its travel range, incorporating features like valve standby control and boom cushion control to enhance responsiveness and reduce vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional automatic control systems are used to maintain implement position, then automation is provided, but responsiveness and precision deteriorate due to inability to accommodate non-linearity of lift assembly dynamics
Solution Approach 1:
The control system dynamically adjusts control parameters based on the actual boom angle and lift assembly configuration. The system transitions from static control algorithms to dynamic control that adapts to changing operational conditions, specifically accommodating the non-linear dynamics of the lift assembly as the boom moves through its range of motion. This is achieved through real-time calculation of control signals that account for the current geometric state of the lift assembly.
Solution Approach 2:
The system changes control parameters based on the boom angle and lift assembly configuration. By monitoring the actual boom angle and using this information to adjust control signals, the system adapts to the non-linear dynamics of the lift assembly. The control algorithm modifies its behavior depending on the operational state, thereby maintaining precision across the entire range of motion.
2Measurement precision
If manual adjustment of implement position is required, then control precision can be maintained, but operator workload increases and materials may be inadvertently dumped
Solution Approach 1:
The control system performs automatic implement position control without requiring continuous manual intervention. The system monitors the boom angle and automatically generates control signals to maintain the desired implement position, effectively making the control task self-executing. This eliminates the need for the operator to constantly adjust the implement position while maintaining high precision control.
Solution Approach 2:
The system uses feedback from boom angle sensors and implement position sensors to continuously monitor the actual state and compare it with the desired state. Based on this feedback, the control algorithm automatically generates corrective control signals to maintain the desired implement position, thereby reducing operator workload while maintaining precision.
3Reliability
If the tilt cylinder transitions between stroked and de-stroked positions, then the implement can maintain target angle, but system responsiveness is reduced due to transition delays
Solution Approach 1:
The control system anticipates the need for tilt cylinder transitions by monitoring the boom angle and predicting when transitions will be required. By preparing control signals in advance and smoothing the transition process, the system reduces the impact of transition delays on overall responsiveness. The feed-forward control component helps initiate adjustments before the actual transition point is reached.
Solution Approach 2:
The system uses periodic control updates based on monitored boom angle changes to manage tilt cylinder transitions. By rhythmically adjusting control signals in response to periodic boom position changes, the system maintains smooth transitions while preserving responsiveness to actual operational needs.
Data Source
AI summary
A method for automatically adjusting the position of an implement of a lift assembly of a work vehicle includes determining a tilt transition boom angle for the lift assembly, determining a closed-loop control signal associated with controlling movement of the implement based at least in part on the tilt transition boom angle, generating a valve command signal based at least in part on the closed-loop control signal, and controlling an operation of at least one valve associated with the implement based at least in part on the valve command signal to maintain the implement at a target implement angle as a boom of the lift assembly is being moved across a boom travel range.