Excavator Boom and Bucket Speed Control to Prevent Hunting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variations in the performance and quality of angle sensors used in working machines lead to fluctuations in the operating speeds of booms, arms, and buckets, causing hunting issues that result in inconsistent earth excavation depths.
Innovation Solution
A working machine equipped with a rotation sensor to measure the rotation of booms, arms, and buckets, and a controller that applies a correction function to the difference between target and actual angular velocities to stabilize the rotation speeds, thereby preventing hunting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angle sensors are used to monitor rotations of boom, arm, and bucket, then rotation measurement is achieved, but variations in sensor performance and quality cause fluctuations in operating speeds
Solution Approach 1:
The controller continuously monitors the actual angular velocity via the rotation sensor and compares it with the target angular velocity. Based on this feedback loop, the controller adjusts the hydraulic actuator commands to correct speed deviations, thereby maintaining consistent operating speeds despite sensor variations.
Solution Approach 2:
The system dynamically adjusts control parameters (angular velocity commands) based on the difference between target and actual values. By modifying the commanded angular velocity in real-time, the system compensates for sensor performance variations and maintains reliable operation.
2Manufacturing precision
If target angular velocity control is implemented, then excavation depth control is improved, but hunting occurs due to speed variations causing the bucket to move up and down
Solution Approach 1:
The controller uses feedback from the rotation sensor to continuously monitor actual angular velocity and compares it with the target value. This closed-loop control detects hunting oscillations and adjusts commands to dampen them, maintaining bucket position stability while achieving precise excavation depth control.
Solution Approach 2:
The correction function anticipates hunting by detecting speed variations before they cause significant bucket position oscillations. By applying corrective control actions in advance, the system prevents hunting from developing, ensuring stable excavation depth.
3Speed
If rotation control based on angular velocity difference is used, then speed accuracy is improved, but system complexity increases due to the correction function
Solution Approach 1:
The correction function modifies the angular velocity command parameter based on the difference between target and actual values. This parameter adjustment approach achieves accurate speed control while maintaining relatively simple control logic that can be implemented in standard controllers.
Data Source
AI summary
A work vehicle includes a boom coupled to a machine body, an arm coupled to the boom, a bucket coupled to the arm and including an edge portion to function as a leading edge when the bucket excavates earth, a rotation sensor to measure rotation of a to-be-measured object which is at least one of the boom, the arm, or the bucket, and a controller configured or programmed to control rotation of the to-be-measured object. The controller is configured or programmed to control rotation of the to-be-measured object based on an output value obtained by applying a correction function directly or indirectly to a difference between a target angular velocity for rotation of the to-be-measured object and an actual angular velocity of the to-be-measured object derived based on a measurement result from the rotation sensor, the correction function being based on the actual angular velocity.