Construction Machine Hydraulic Control Mode Switching
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Solution Overview
Problem
Existing construction machines fail to consistently achieve desired moving velocity and thrust corresponding to operator input, especially under conditions with large reaction forces, leading to reduced work efficiency and requiring skilled operators.
Innovation Solution
A construction machine with a hydraulic circuit and controller that switches between thrust control mode and velocity control mode based on reaction force and operational conditions, using pressure and flow rate sensors to adjust the hydraulic cylinder's thrust and velocity accordingly, ensuring optimal performance regardless of operator skill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the discharge rate of the hydraulic pump is increased to increase the moving velocity of the hydraulic cylinder, then the moving velocity increases, but when a large reaction force is applied (excavation or leveling work), the relief valve opens and the moving velocity does not increase accordingly
Solution Approach 1:
The control system dynamically switches between velocity control mode and thrust control mode based on operational conditions. When reaction force is large (excavation/leveling), the system transitions from velocity control to thrust control, allowing the hydraulic cylinder thrust to vary according to operation lever amount rather than maintaining fixed velocity control, thus preventing relief valve opening and achieving desired thrust without velocity loss
Solution Approach 2:
The controller changes the control parameter from velocity (flow rate) to thrust (pressure) based on the operation mode. In thrust control mode, the opening amount of the control valve is adjusted according to the operation lever input to directly control hydraulic cylinder thrust, bypassing the velocity-control limitation that causes relief valve activation under high load
2Ease of operation
If the opening of the control valve is changed according to the operation amount to achieve desired moving velocity and thrust, then the responsiveness improves, but it cannot always achieve the desired moving velocity and thrust, reducing work efficiency
Solution Approach 1:
The system incorporates feedback control by monitoring the actual thrust and velocity of the hydraulic cylinder and comparing them with target values. The controller adjusts the control valve opening based on feedback signals to maintain desired thrust or velocity, ensuring that operator input is accurately translated into intended mechanical output regardless of load conditions
Solution Approach 2:
The control system dynamically adapts between velocity control and thrust control modes based on real-time operational conditions. This dynamic switching ensures that the control strategy matches the actual work requirements, maintaining both responsiveness to operator input and achievement of desired performance metrics
3Speed
If the opening area of the valve increases to increase hydraulic oil flow and hydraulic cylinder movement, then the moving velocity increases, but the thrust generated does not always correspond to the operation amount
Solution Approach 1:
The system dynamically switches control modes based on operational needs. In thrust control mode, the control valve opening is adjusted to directly control hydraulic pressure and thrust according to operation lever input, independent of velocity considerations. This decouples thrust control from velocity control, allowing independent optimization of both parameters
Solution Approach 2:
The control system changes the primary controlled parameter from velocity (flow rate through valve opening) to thrust (hydraulic pressure). By controlling the control valve opening to regulate pressure rather than flow rate, the system achieves thrust corresponding to operation amount without being constrained by velocity requirements
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 machine effectively generates the required thrust or velocity corresponding to operator input, enhancing work efficiency even with low-skilled operators and maintaining performance under varying operational conditions.
Implementation Method 1
a hydraulic circuit configured to supply hydraulic oil to the hydraulic cylinder
Implementation Method 2
using pressure and flow rate sensors to adjust the hydraulic cylinder's thrust and velocity
Implementation Method 3
using pressure and flow rate sensors to adjust the hydraulic cylinder's thrust and velocity
Data Source
AI summary
A construction machine includes a hydraulic cylinder configured to drive an attachment, a hydraulic circuit configured to supply hydraulic oil to the hydraulic cylinder, an input device that is operated by an operator, and a controller configured to control the hydraulic circuit in at least one of a first control mode where the attachment is caused to generate a force corresponding to an operation amount of the input device and a second control mode where the attachment is driven at a velocity corresponding to the operation amount of the input device.