Hybrid Excavator Swing Control Torque Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid hydraulic excavators face issues with operability due to insufficient torque generation by electric motors during combined operations, leading to unbalanced boom and swing movements, which can result in poor handling and increased operator effort.
Innovation Solution
A hybrid construction machine design that incorporates a control system allowing for hydraulic/electric complex swing control and hydraulic solo swing control, adjusting the torque distribution between electric and hydraulic motors to maintain balanced operations, ensuring satisfactory operability regardless of the electric motor's status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an electric motor is used to drive the swing structure, then energy efficiency is improved and kinetic energy can be regenerated, but operability deteriorates due to insufficient torque generation during combined operations
Solution Approach 1:
The patent combines an electric motor and a hydraulic motor to drive the swing structure, merging two different actuation systems. The electric motor provides energy efficiency and regeneration capabilities, while the hydraulic motor supplements torque output during combined operations, ensuring both energy efficiency improvement and operability maintenance are achieved simultaneously
Solution Approach 2:
The control device dynamically adjusts the torque distribution parameters between the electric motor and hydraulic motor based on operating conditions. By changing the torque split ratio in real-time, the system optimizes energy efficiency during electric motor operation while ensuring sufficient total torque during combined operations, thus resolving the contradiction between energy efficiency and operability
2Loss of energy
If an electric motor is used for swing driving, then energy regeneration is enabled, but torque insufficiency occurs during combined swing and boom operations
Solution Approach 1:
The system merges electric motor and hydraulic motor for swing driving, allowing the electric motor to handle normal operations with energy regeneration while the hydraulic motor provides additional torque support during combined operations. This combination enables both energy regeneration capability and sufficient torque generation to be achieved simultaneously
Solution Approach 2:
The control device acts as an intermediary that manages torque distribution between the electric motor and hydraulic motor. It monitors operating conditions and adjusts the torque split ratio to ensure the total torque from both motors is sufficient during combined operations, while allowing the electric motor to operate independently for energy regeneration during normal operations
3Ease of operation
If hydraulic/electric complex swing control is implemented, then operability is maintained, but control complexity increases
Solution Approach 1:
The control device uses feedback from swing operating lever operation amount and electric motor status to dynamically adjust torque distribution. By continuously monitoring these parameters and adjusting the torque split ratio in real-time, the system maintains operability through adaptive control while managing complexity through systematic feedback-based decision making
Solution Approach 2:
The control system transitions from static torque allocation to dynamic torque distribution based on real-time operating conditions. The torque split ratio is continuously adjusted according to swing operating lever operation amount and electric motor status, making the control system adaptive and responsive. This dynamic approach maintains operability across varying operating conditions while organizing complexity through systematic adaptation
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 secures stable and efficient combined operation of swing and boom functions, reducing operator effort and preventing accidents by maintaining balanced torque distribution and swing speeds.
Implementation Method 1
the electric motor regenerates the kinetic energy of the swing structure into electric energy
Implementation Method 2
a hydraulic pump which is driven by the prime mover
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In hybrid construction machine employing a hydraulic motor and an electric motor for the driving of the swing structure, satisfactory operability of a combined operation of the swing structure and other actuators is secured irrespective of the operating status of the electric motor. A control device of the hybrid construction machine executes control selected from: hydraulic/electric complex swing control for driving the swing structure by total torque of the electric motor and the hydraulic motor when a swing operating lever device is operated; and hydraulic solo swing control for driving the swing structure by the torque of the hydraulic motor alone when the swing operating lever device is operated. The control device controls drive torque or driving force of each of the electric motor, the hydraulic motor and a second hydraulic actuator so that the relationship between the position or the speed of the second hydraulic actuator and the swing angle or the swing speed of the swing structure in the combined operation when the swing operating lever device and a second operating lever device are operated at the same time during the hydraulic/electric complex swing control is substantially identical with the relationship in the combined operation during the hydraulic solo swing control.