Machine Energy Threshold Control for Safe Return to Charging
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Solution Overview
Problem
Electric and hydrogen-powered off-highway working machines face challenges in maintaining productivity due to the risk of fully discharging their energy sources, such as batteries or fuel cells, while operating at a worksite, necessitating timely recharging or refueling to avoid operational interruptions.
Innovation Solution
A control system that monitors the energy level of the working machine and calculates a travel energy threshold to reach a charging or refueling location, providing alerts when the energy level is equal to the threshold, and activates restricted or limp home modes to ensure safe return to the charging point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the working machine operates continuously at the worksite, then productivity is improved, but the risk of energy source depletion increases
Solution Approach 1:
The control system calculates a travel energy threshold that includes not only the energy needed to reach the charging location but also a safety margin. This preliminary calculation prevents the machine from operating with insufficient energy reserves, resolving the contradiction by proactively managing energy levels before depletion occurs.
Solution Approach 2:
The system continuously monitors the actual energy level and compares it against the travel energy threshold. When the actual energy level approaches the threshold, the system provides feedback to the operator through alerts, enabling timely decision-making about returning to charge while maintaining maximum productive operation.
2Reliability
If the working machine returns to charging location frequently, then energy source depletion is prevented, but productivity decreases
Solution Approach 1:
The system calculates the travel energy threshold in advance, incorporating the energy required for the return journey. This allows the machine to operate closer to maximum capacity while still ensuring sufficient energy reserves for returning to the charging location, thereby minimizing unnecessary early returns and maximizing productivity.
Solution Approach 2:
The system allows the machine to operate with energy levels partially depleted (down to the calculated threshold) rather than requiring frequent returns at higher energy levels. This excessive action approach enables longer continuous operation cycles while maintaining a safety buffer for the return journey.
3Reliability
If the travel energy threshold is calculated conservatively, then safe return is ensured, but work time is reduced
Solution Approach 1:
The control system performs preliminary calculations of the travel energy threshold by analyzing the route to the charging location and determining the precise energy requirements. This accurate preliminary assessment allows for an optimized threshold that ensures safe return while maximizing the available work time before the alert is triggered.
4Reliability
If the working machine operates with high energy reserves, then safe return is ensured, but productivity decreases due to early returns
Solution Approach 1:
The system dynamically determines the travel energy threshold based on specific parameters including route distance, terrain conditions, and machine energy consumption characteristics. This parameter-based approach optimizes the energy reserve requirement, allowing the machine to operate with minimal necessary reserves rather than excessive margins, thereby maximizing productivity while ensuring safe return.
Data Source
AI summary
A control system for an off-highway working machine includes a ground engaging propulsion structure for propelling the working machine, a body supported on the ground engaging propulsion structure, a drive arrangement, and a transmission operable to transmit drive to the ground engaging propulsion structure. The control system calculates a travel energy threshold required to enable the working machine to travel to the charging location, and provide an alert based on the travel energy threshold.