Crowd Runaway Control for Electric Rope Shovels
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Solution Overview
Problem
Industrial machines like electric rope shovels experience control issues during 'crowd runaways' due to excessive payload, leading to uncontrolled dipper movement and increased cycle times, potentially causing damage and inefficiency.
Innovation Solution
A control system that monitors actual and requested dipper positions, adjusting crowd motor torque or setting brakes to resolve runaway conditions by comparing the two states and applying corrective forces or parameters when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dipper is filled with excessive payload, then the digging capacity is improved, but the crowd control becomes unstable and runaway conditions occur
Solution Approach 1:
The control system continuously monitors the actual crowd system state (dipper position, crowd motor position) and compares it with the requested state. When a runaway condition is detected (difference exceeds threshold), the system automatically adjusts the crowd motor torque to resolve the condition, creating a closed-loop feedback control mechanism that maintains stability even with excessive payload
Solution Approach 2:
The system dynamically changes the crowd motor operating parameters (torque, speed) based on the detected runaway condition. The controller sets the crowd motor parameter to a corrective value when the difference between actual and requested states exceeds a threshold, allowing the system to adapt to varying load conditions and prevent instability
2Productivity
If the swing speed is increased to improve productivity, then the digging efficiency is improved, but the centrifugal forces increase causing crowd runaway
Solution Approach 1:
The control system proactively detects runaway conditions by comparing actual and requested dipper positions before the condition worsens. When a potential runaway is detected (difference exceeds threshold), the system preemptively adjusts the crowd motor torque to counteract the centrifugal forces, preventing full runaway rather than reacting after it occurs
Solution Approach 2:
The real-time monitoring and comparison of actual versus requested crowd system state provides continuous feedback that allows the system to detect and correct runaway conditions caused by high swing speeds, enabling the operator to maintain higher productivity without compromising control
3Stability of the object's composition
If the crowd motor torque is increased to resolve runaway, then the control stability is improved, but the energy consumption increases
Solution Approach 1:
The system applies corrective torque only to the extent necessary to resolve the runaway condition. The controller monitors the difference between actual and requested states and applies minimal corrective action (setting crowd motor parameter to a value greater than normal operating value only when difference >= threshold), avoiding excessive energy consumption while maintaining control stability
Solution Approach 2:
The control system operates in discrete correction cycles, monitoring the crowd system state continuously and applying corrective torque only when runaway conditions are detected. Once the condition is resolved, the system returns to normal operation, creating a periodic rather than continuous high-energy state
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 regains control of the dipper movement, reducing cycle times and preventing damage by dynamically adjusting motor parameters to align actual and requested movements, thereby enhancing operational efficiency and safety.
Implementation Method 1
a crowd motor torque
Implementation Method 2
setting the brakes for one or more system motors
Implementation Method 3
the swing speed and the resultant centrifugal forces on the dipper
Data Source
AI summary
A system for controlling the operation of an industrial machine during crowd runaway conditions. The system includes a controller that monitors and compares an actual crowd system state (e.g., an actual dipper position) with a requested crowd system state (e.g., a requested dipper position from the operator). If the controller determines that the crowd system is behaving contrary to requested crowd system behavior, the controller adjusts a crowd parameter, such as a crowd motor torque, to resolve the runaway condition.