Front Work Implement Control With Load Feedback for Accurate Excavation
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Solution Overview
Problem
Existing work machines, such as hydraulic excavators, struggle to accurately control the operating velocities of hydraulic cylinders due to varying loads on the front work implement, leading to inaccurate excavation along construction target surfaces and difficulty for operators to recognize load status.
Innovation Solution
A work machine equipped with a controller that calculates target velocities and correction amounts for actuators based on operation inputs, posture sensors, load sensors, and distance to the construction target surface, allowing for accurate operation and load recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the operating velocities of hydraulic cylinders are controlled based on a fixed operation command value, then the control system is simple, but the excavation accuracy deteriorates when the load on the front work implement varies
Solution Approach 1:
The control system incorporates feedback from load sensors that detect the load on the front work implement. The controller adjusts the operation command values for hydraulic cylinders based on this load feedback, enabling the system to maintain excavation accuracy by compensating for load variations. This feedback mechanism resolves the contradiction by dynamically adapting the control parameters rather than using fixed values.
Solution Approach 2:
The operation command values for the hydraulic cylinders are made dynamic rather than static. The controller continuously adjusts these command values based on the detected load conditions, allowing the system to adapt to varying work conditions. This dynamic adjustment enables accurate excavation control under different loads without requiring an overly complex control architecture.
2Ease of operation
If the operating velocities of hydraulic cylinders remain constant irrespective of load, then the control system is simple, but the operator's ability to recognize load status deteriorates
Solution Approach 1:
The system provides feedback to the operator about the load status on the front work implement through the controlled variation in hydraulic cylinder operating velocities. When the load increases, the controller adjusts the operation command values to maintain appropriate velocities, and this adjustment process itself becomes a feedback mechanism that helps the operator perceive load conditions through the machine's response.
Solution Approach 2:
The hydraulic system acts as an intermediary that translates load conditions into observable operational characteristics. The controller's adjustment of operation command values based on load sensors creates an intermediate signal that the operator can perceive through the machine's behavior, enabling load recognition without direct sensory feedback.
3Manufacturing precision
If the operation command value for hydraulic cylinders is adjusted based on load variations, then the excavation accuracy improves, but the energy consumption increases
Solution Approach 1:
The controller adjusts the operation command values for hydraulic cylinders by changing operational parameters based on detected load conditions. This parameter adjustment allows the system to maintain excavation accuracy under varying loads while optimizing energy consumption by adapting the hydraulic flow and pressure requirements to actual work demands rather than maintaining constant high-energy operation.
Data Source
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AI summary
It is an object of the present invention to provide a work machine that is capable of making a working attachment operate accurately along a construction target surface in the vicinity thereof and of allowing an operator to operate the work machine while recognizing the load acting on a front work implement thereof when the working attachment is not in the vicinity of the construction target surface. To accomplish the object, a controller calculates target velocitys for actuators on the basis of an operation amount from an operation input device, postures of a machine main body and the front work implement, and the distance between the working attachment and the construction target surface, calculates operation command values for the actuators on the basis of the target velocitys, calculates correction amounts for the operation command values on the basis of loads on the actuators sensed by a load sensor 27, and adds the correction amounts to the operation command values.