Dynamic Crowd Torque Control for Electric Rope Shovel Tipping
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Solution Overview
Problem
Industrial machines like electric rope shovels experience abrupt dipper stops during digging, leading to boom jacking and rearward tipping, which causes structural fatigue and reduces operational life due to uncontrolled crowd and hoist forces.
Innovation Solution
A control system that dynamically limits crowd torque based on hoist bail pull and increases maximum allowable retract torque, using a controller to monitor impact events and adjust torque limits to prevent rearward tipping moments and center-of-gravity excursions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If crowd torque is increased to improve digging capability, then productivity increases, but rearward tipping moments and structural fatigue increase
Solution Approach 1:
The patent applies dynamics by making the crowd torque limit dynamic rather than static. The controller continuously adjusts the crowd torque limit based on real-time operating conditions, including hoist bail pull levels and dipper acceleration, allowing the system to optimize between productivity and structural stress reduction throughout the digging operation.
Solution Approach 2:
The patent changes the parameter of crowd torque limit based on multiple factors including hoist bail pull level and dipper acceleration. By adjusting this parameter dynamically, the system can maximize digging capability when safe and reduce torque to minimize structural fatigue when conditions require caution.
2Strength
If crowd torque is limited to reduce rearward tipping moments, then structural fatigue decreases, but digging capability is reduced
Solution Approach 1:
The system dynamically adjusts crowd torque limits based on real-time conditions rather than applying a fixed restriction. When hoist bail pull is low and dipper acceleration indicates safe conditions, higher torque limits are permitted, maintaining digging capability. When conditions change, the limit adjusts to protect the structure.
Solution Approach 2:
The controller uses feedback from sensors monitoring hoist bail pull, dipper acceleration, and other operating parameters to continuously adjust the crowd torque limit. This feedback mechanism ensures that torque restrictions are applied only when necessary to prevent structural fatigue, while allowing maximum torque when conditions are safe.
3Reliability
If maximum retract torque is increased to handle impact events, then boom jacking is reduced, but control complexity increases
Solution Approach 1:
The system performs self-service by automatically detecting impact events through acceleration sensors and autonomously adjusting retract torque limits without requiring complex external control systems or manual intervention. The controller monitors dipper acceleration and automatically implements appropriate torque restrictions when impacts are detected.
Solution Approach 2:
The patent replaces complex mechanical shock-absorption mechanisms with an electrical/control-based solution. Instead of relying on purely mechanical systems to handle impact events, the invention uses electronic sensors and control algorithms to detect impacts and adjust torque, simplifying the overall system while improving reliability.
4Duration of action of stationary object
If dynamic torque adjustment is implemented to manage forces, then operational life increases, but control system complexity increases
Solution Approach 1:
The control system performs self-service by automatically monitoring operating conditions and adjusting torque limits without requiring complex external control systems. Sensors continuously monitor parameters like hoist bail pull and dipper acceleration, and the controller autonomously implements appropriate adjustments to extend operational life.
Solution Approach 2:
The system uses feedback from multiple sensors to continuously monitor operating conditions and adjust torque limits in real-time. This feedback mechanism enables the system to adapt to changing conditions and prevent structural fatigue, extending operational life through intelligent control rather than complex mechanical systems.
Data Source
AI summary
Controlling a digging operation of an industrial machine that includes a dipper, a crowd motor drive, and a controller. The crowd motor drive is configured to provide one or more control signals to a crowd motor, and the crowd motor is operable to provide a force to the dipper to move the dipper toward or away from a bank. The controller is connected to the crowd motor drive and is configured to monitor a characteristic of the industrial machine, identify an impact event associated with the dipper based on the monitored characteristic of the industrial machine, and set a crowd motoring torque limit for the crowd motor drive when the impact event is identified.