Hydraulic Excavator Boom Control for Surface Accuracy and Fuel Efficiency
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Solution Overview
Problem
Hydraulic excavators face challenges in achieving high accuracy for target construction surface formation while minimizing fuel consumption, particularly when excavating hard ground, which can lead to increased load on bucket teeth tips and inefficient fuel use.
Innovation Solution
A hydraulic excavator with a multi-joint work device and a controller that calculates trajectory and power corrective control signals for hydraulic actuators to maintain the work device's motion trajectory above the target surface and adjust power based on actual vs. target power differences, preventing overload and optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bucket teeth tips are controlled to move along the target construction surface by automatic boom raising, then the accuracy of forming the target construction surface is improved, but the fuel efficiency deteriorates due to increased power consumption when excavating hard ground
Solution Approach 1:
The control system dynamically adjusts the boom raising velocity based on real-time detection of actuator power states. When hard ground is detected through power threshold comparison, the system automatically modifies the boom raising speed to prevent excessive load on the bucket teeth tips, thereby maintaining excavation accuracy while optimizing fuel consumption.
Solution Approach 2:
The system implements feedback control by continuously monitoring the power state of the arm or bucket actuator and comparing it against predetermined thresholds. This feedback mechanism enables the controller to detect when the excavator encounters hard ground and automatically adjust the boom raising velocity accordingly, resolving the contradiction between formation accuracy and fuel efficiency.
2Productivity
If the load on the bucket teeth tips is increased to excavate hard ground, then the excavation efficiency is improved, but the reliability deteriorates due to potential stopping of the front work device operation
Solution Approach 1:
The system performs preliminary detection of hard ground conditions by monitoring actuator power states before the bucket teeth tips encounter excessive load. When hard ground is detected in advance through power threshold comparison, the controller proactively adjusts the boom raising velocity to prevent operational stopping, thereby maintaining both excavation efficiency and reliability.
Solution Approach 2:
The control system dynamically modifies the boom raising velocity based on real-time power state detection. When the actuator power exceeds predetermined thresholds indicating hard ground, the system automatically adjusts operational parameters to maintain continuous work device operation, preventing stopping while preserving excavation efficiency.
3Reliability
If the number of excavations is increased to avoid overload on the bucket teeth tips, then the reliability is improved, but the productivity deteriorates due to increased fuel consumption
Solution Approach 1:
The system uses feedback control to continuously monitor actuator power states and automatically adjust boom raising velocity. This real-time feedback mechanism prevents overload conditions by detecting hard ground through power thresholds, thereby maintaining operational reliability while avoiding the need for multiple excavations and the associated increased fuel consumption.
Solution Approach 2:
The control system dynamically adjusts the boom raising velocity based on detected power states of the hydraulic actuators. By continuously adapting operational parameters to match ground conditions, the system maintains reliable operation without requiring repeated excavations, thus preserving productivity while ensuring operational continuity.
Data Source
AI summary
The invention provides a work machine that achieves high accuracy of forming a target construction surface and reduced fuel consumption. A trajectory corrective Pi pressure calculation section calculates a trajectory corrective pressure, which is a control signal for a boom cylinder, based on the distance from a front work device to a target construction surface such that the motion trajectory of the work device is maintained above the target construction surface. A power corrective Pi pressure calculation section calculates a power corrective pressure, which is a control signal for the boom cylinder, based on the bottom pressure of an arm cylinder when the difference between the target power and actual power of the arm cylinder is larger than a predetermined output power value. The boom cylinder is controlled based on the larger of the power corrective pressure and the trajectory corrective pressure while the arm cylinder is being operated.