Open Loop Electrohydraulic Bucket Position Control
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Solution Overview
Problem
Existing work machine control systems for adjusting bucket position are complex and require numerous sensors, leading to maintenance and calibration challenges, necessitating a simpler and more efficient control system.
Innovation Solution
An electrohydraulic bucket position control system that uses a processor and memory to determine boom and bucket velocities from operator commands, calculating a combined command to adjust the bucket position, reducing the need for positional sensors and simplifying the control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a closed loop control system with multiple sensors is used to maintain bucket level, then the bucket position control accuracy is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for multiple position sensors (boom angle sensors, bucket angle sensors) from the control system. Instead of using sensor feedback, the system uses open-loop control with pre-programmed control logic that calculates hydraulic cylinder commands based on desired boom and bucket positions, thereby reducing device complexity while maintaining control accuracy
Solution Approach 2:
The patent replaces the mechanical sensor-based feedback system with a software-based open-loop control system. The controller uses programmed algorithms to calculate the required hydraulic cylinder movements to achieve desired bucket position, substituting physical measurement devices with computational control logic
2Manufacturing precision
If multiple sensors are installed for boom and bucket position feedback, then the control precision is improved, but the maintenance burden and calibration requirements increase
Solution Approach 1:
The patent removes all position sensors (boom angle sensors, bucket angle sensors) from the system, eliminating the maintenance and calibration burden associated with these components. The open-loop control achieves bucket level maintenance through software calculations without requiring any physical sensing devices
Solution Approach 2:
The control system performs self-calibration and self-adjustment through programmed logic. The controller automatically calculates the required hydraulic cylinder movements to maintain bucket level based on predefined geometric relationships and control algorithms, without requiring external calibration procedures or sensor adjustments
3Device complexity
If an open loop control system is used to reduce complexity, then the device complexity is reduced, but the bucket position control accuracy may deteriorate
Solution Approach 1:
The patent implements preliminary action by pre-programming the control logic with the geometric relationships and control algorithms needed to maintain bucket level. The controller contains pre-calculated data and instructions that enable it to automatically determine the correct hydraulic cylinder commands to achieve desired bucket position, compensating for the lack of real-time sensor feedback
Solution Approach 2:
The patent changes the control approach from feedback-based (closed-loop) to feedforward-based (open-loop) control. The system uses pre-programmed parameters and control logic to predict and achieve the desired bucket position based on the commanded boom and bucket movements, rather than reacting to sensor feedback
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 effectively maintains the bucket at a level position during boom movement, reducing complexity and maintenance costs by eliminating the need for multiple sensors and relying on empirically gathered data and software control.
Implementation Method 1
a boom hydraulic actuator operatively connected to the boom operator control
Implementation Method 2
The processor is configured to execute the stored program instructions to: determine a boom velocity of the boom based on the operator boom command; determine a bucket velocity of the bucket based on the operator bucket command
Data Source
AI summary
An open loop electrohydraulic bucket position control system for a work vehicle having a positionable bucket coupled to a movable boom. The bucket control system maintains a position of the bucket with respect to a frame of the vehicle as the movable boom is raised or lowered. A bucket command, determined by an operator of the vehicle, is modified based on a pre-determined relationship of the work vehicle's hardware and known and constant properties of a linkage design of the work machine. The control system includes a processor and one or more look-up tables that include data identifying implement velocities with respect to boom commands and implement velocities with respect to bucket commands. Bucket commands are modified based on a relationship between the commanded velocity of the boom and a level orientation of the bucket during the commanded heights of the boom. Modified bucket commands and boom commands adjust the position of a bucket hydraulic cylinder and a boom hydraulic cylinder.