Battery-Aware Hydraulic Crane Arm Flow Control
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Solution Overview
Problem
Existing electrically powered hydraulic cranes face challenges in maintaining controllability and power efficiency due to varying battery charging levels and output, leading to potential system failures when battery capacity is low.
Innovation Solution
The system dynamically adapts the maximum hydraulic flow limit based on available battery capacity and current consumption, scaling down flow demand to prevent exceeding battery limits, ensuring high controllability and efficient energy use by adjusting the operation of hydraulic functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predefined constant flow limit is set in the hydraulic system, then the equipment controller can maintain stable operation, but the system cannot adapt to varying battery capacity leading to potential system failures when battery capacity is low
Solution Approach 1:
The patent applies dynamics by transitioning from a static, predefined flow limit to a dynamic flow limit that automatically adjusts based on real-time battery capacity detection. The equipment controller continuously monitors battery capacity and modifies the hydraulic flow limit accordingly, enabling the system to adapt to varying battery conditions and prevent failures during operation.
Solution Approach 2:
The patent implements feedback by establishing a closed-loop control system where the equipment controller detects battery capacity status and uses this information to adjust the hydraulic flow limit. This feedback mechanism ensures the system responds to changing battery conditions, maintaining reliable operation while adapting to available power resources.
2Duration of action of moving object
If the battery charging level is allowed to decrease during operation, then longer operational time is achieved, but the available output from the battery decreases leading to reduced controllability
Solution Approach 1:
The patent applies dynamics by continuously adjusting the hydraulic flow limit as battery capacity changes during operation. As the battery discharges and capacity decreases, the flow limit is automatically reduced to match available power, ensuring controllability is maintained throughout the entire operational period rather than being constrained by initial battery capacity.
Solution Approach 2:
The patent changes the operational parameter of hydraulic flow limit based on battery capacity status. By modifying this parameter dynamically as the battery discharges, the system extends operational time while preserving controllability within the bounds of available power, avoiding system failure or loss of control.
3Ease of operation
If the flow demand from the hydraulic system is increased to maintain high controllability, then operational performance is improved, but the battery capacity is exceeded leading to system failure
Solution Approach 1:
The patent implements feedback by continuously monitoring battery capacity and using this information to adjust the hydraulic flow limit. This prevents the system from demanding more power than the battery can provide, avoiding over-discharge and system failure while maintaining the highest possible controllability within safe operating limits.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting the flow limit based on detected battery capacity before the battery is exhausted. This preventive approach avoids system failure by ensuring the hydraulic demand never exceeds available power resources.
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
This approach maintains high controllability and extends battery life, allowing for longer operational times and reduced costs by optimizing power usage, enabling cranes to operate at reduced speeds with full control even at lower battery levels, thus enhancing the attractiveness of battery-powered equipment.
Implementation Method 1
an electric motor powered by a battery may drive a hydraulic pump
Implementation Method 2
a hydraulic pump that is generating a flow of the fluid in the hydraulic system
Data Source
Figure 1
Figure 2
AI summary
A working equipment (2) comprising a hydraulically movable arm arrangement (4) for a crane, at least one electric motor (6) arranged to be powered by a battery system (8), at least one hydraulic pump (10) arranged to be operated by the electric motor (6), and a pump controller (12) configured to control the electric motor (6) and/or the hydraulic pump (10), and to monitor the current consumption (13) of the at least one electric motor (6). A plurality of actuators (14) is provided, arranged to be operated by hydraulic fluid discharged from the at least one hydraulic pump (10) and further arranged to move the movable arm arrangement (4) during a working assignment, and an equipment controller (16) configured to control movement of the movable arm arrangement (4) by generating operating signals (18) controlling the flow and/or pressure of hydraulic fluid to the plurality of actuators (14). The equipment controller (16) is arranged to determine a maximum flow limit of the hydraulic fluid from the at least one pump in dependence of a comparison of the current limit received from the battery system (8) and the current consumption (13) monitored by the pump controller (12). The equipment controller (16) is configured to compare said determined maximum flow limit with the required flow of hydraulic fluid from the at least one pump (10) needed to move the movable arm arrangement (4) in accordance with the operating signals, and if the result of the comparison does not fulfil at least one rule of a set of fluid control rules, the equipment controller (16) is configured to adapt the operating signals (18) to reduce the flow of hydraulic fluid to at least one of the plurality of actuators (14) according to at least one rule of a set of adaptation rules, such that at least one rule of said set of fluid control rules is fulfilled.