Work Tool Position Control for Automatic Thumb–Arm Clearance
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Solution Overview
Problem
Existing work tool controls for construction machines, such as excavators, fail to prevent the thumb from contacting and damaging the arm when the thumb is in an open position, necessitating its removal when not needed, which is inefficient and potentially harmful to the machine.
Innovation Solution
A work tool position control system that includes a bucket control, thumb position sensor, and controller to monitor and adjust the position of the thumb relative to the bucket, preventing interference with the arm by calculating future positions and sending actuation signals to the hydraulic system to avoid collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the thumb is left in an open position during bucket movement, then the work tool can maintain operational flexibility, but the thumb may contact and damage the arm
Solution Approach 1:
The controller proactively moves the thumb to a safe position before the bucket movement causes potential interference. By calculating the future position of the bucket and determining that interference will occur, the system preemptively repositions the thumb, preventing the harmful contact before it can happen.
Solution Approach 2:
The system uses position sensors to continuously monitor the actual positions of the bucket and thumb, comparing them against the planned movement trajectory. This feedback loop enables the controller to detect when the thumb deviates from the safe position relative to the bucket's future position, triggering automatic correction to prevent interference.
2Object-affected harmful factors
If the thumb is removed from the work tool when not needed, then damage risk to the arm is eliminated, but the work tool becomes less efficient and requires additional manual intervention
Solution Approach 1:
The thumb positioning system operates autonomously without requiring operator intervention. The controller automatically monitors sensor data, calculates potential interference scenarios, and actuates the thumb to appropriate positions based on the bucket's movement, enabling the system to protect itself and maintain efficiency simultaneously.
3Object-affected harmful factors
If a control system monitors and autonomously repositions the thumb, then damage prevention is achieved, but the device complexity increases
Solution Approach 1:
The controller integrates multiple functions within a single device: it processes position sensor data from both the bucket and thumb, calculates future bucket positions based on movement signals, determines interference risk, and actuates the thumb positioning mechanism. This multi-functionality reduces the need for separate dedicated components for each control task.
Data Source
AI summary
A work tool position control for a work machine is disclosed. A bucket control is used to adjust the bucket of the work tool relative to an arm of a work machine. A controller receives a bucket movement signal from the bucket control and moves the bucket. A thumb position sensor is used to measure an opening angle between a thumb of the work tool and the bucket, and the measured opening angle is sent from the thumb position sensor to the controller prior to the controller moving the bucket.