Loader Lift Arm Control System Automated Return-to-Dig
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Solution Overview
Problem
Existing systems for controlling lift arms and implements in machines, such as skid steer loaders, rely heavily on multiple position sensors, increasing cost and complexity while not allowing for automated return to a preselected position without operator attention, which hinders efficiency in repetitive tasks.
Innovation Solution
A system that uses a controller to store a desired inclination signal for an implement and automatically moves the lift arm and implement to a predetermined position, utilizing an electro-hydraulic actuation system and angle sensors to adjust the implement's angle and lift arm position, allowing for automated return to a 'return-to-dig' position without the need for multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple position sensors are used to control implement position, then measurement precision and control accuracy are improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the position measurement function from multiple complex position sensors and implements it through a simplified sensor system that uses the existing boom angle sensor combined with geometric relationships. This eliminates the need for multiple position sensors while maintaining measurement capability.
Solution Approach 2:
The patent introduces an intermediary computational approach where the controller calculates implement position based on boom angle measurements and known geometric relationships rather than directly measuring position with multiple sensors. This intermediary calculation method reduces sensor requirements.
2Device complexity
If automated return-to-dig mode is implemented without multiple position sensors, then device complexity is reduced, but measurement precision and control accuracy may deteriorate
Solution Approach 1:
The patent implements feedback control where the controller continuously monitors boom angle sensor readings and adjusts hydraulic actuator commands to achieve the desired return-to-dig position. This feedback mechanism ensures accurate positioning despite using fewer sensors.
Solution Approach 2:
The patent replaces direct mechanical position sensing with a computational approach that uses angular measurements and geometric calculations to determine position. This substitution maintains measurement precision while reducing physical sensor requirements.
3Productivity
If operator manually steers and adjusts implement position simultaneously, then productivity is maintained, but ease of operation decreases
Solution Approach 1:
The patent implements preliminary action by automatically executing the return-to-dig sequence once the operator initiates it. The system pre-programmed the return path and automatically controls the implement and boom to return to the starting position, eliminating the need for manual intervention during the return phase.
Solution Approach 2:
The patent enables self-service operation where the automated return-to-dig system performs the return maneuver autonomously without continuous operator attention. The system serves itself by automatically controlling hydraulic actuators to position the implement and boom, freeing the operator to focus on steering and material handling decisions.
Data Source
AI summary
A system for a loader stores a signal indicative of a desired inclination of an implement. Upon receiving an operator interface actuation signal, a controller transmits a signal to move the implement to the stored inclination. The controller further transmits a lift arm command signal to move a lift arm towards a lower limit of travel of the lift arm. The lift arm command signal is terminated after the controller receives a signal from a sensor on the lift arm indicating that the lift arm is near its lower limit of travel. After the command signal is terminated, the controller may transmit a second lift arm command signal to further move the lift arm.