Shovel Boom Limit Control Using Second-Order Polynomial
Solution Overview
Problem
Current boom limit systems for electric rope shovels either require excessive computational power for precise calculations, leading to delays in motor control, or use simple linear relationships that result in unnecessary slowdowns and longer cycle times due to inaccurate profiling and increased motor loading.
Innovation Solution
A new boom limit system that defines dipper to boom relative position using a second-order polynomial of crowd amount or hoist length, incorporating a slow speed region and field-strengthening region to vary speed references, reducing calibration time and improving motor reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If precise calculations are used to determine dipper position, then measurement precision is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent changes the mathematical model from complex precise calculations to a simplified second-order polynomial relationship between crowd amount/hoist length and dipper position. This parameter change maintains sufficient accuracy for boom limit determination while dramatically reducing computational complexity and processing time requirements.
2Device complexity
If simple linear relationships are used for boom limits, then device complexity is reduced, but measurement precision deteriorates causing unnecessary slowdowns
Solution Approach 1:
The patent transitions from simple linear relationships to second-order polynomial relationships to model the dipper position relative to boom limits. This parameter change captures the non-linear motion characteristics of the dipper more accurately, eliminating unnecessary slowdowns while keeping the control system relatively simple.
3Productivity
If boom limits are enforced with simple linear models, then productivity is maintained, but reliability decreases due to inaccurate profiling
Solution Approach 1:
The patent uses second-order polynomial parameters to accurately profile the boom limits and dipper position relationship. This improved parameter model provides reliable boom contact prevention by accurately determining when the dipper approaches boom limits, while maintaining productivity through appropriate speed references that only reduce speed when truly necessary.
Data Source
AI summary
A system for limiting contact between a dipper and dipper attachments and a boom and machinery desk of a shovel, the system defining dipper to boom relative position in terms of crowd amount or hoist length, the system defining the relative position boom limits in terms of a second order polynomial of crowd amount or hoist length. The system also includes a slow speed region of the crowd amount and the hoist length, where the speed is varied depending on the crowd amount or the hoist length. The system also includes a field-strengthening region, depending on the crowd amount or the hoist length, where the field weakening is removed.