Hydraulic Actuator Speed Limiting for First-Use Excavator Control
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Solution Overview
Problem
Construction machines like hydraulic excavators face issues with operators performing wrong operations due to unrecognized differences in operation assignments between different manufacturers, leading to potential unsafe and inefficient operation.
Innovation Solution
A construction machine equipped with a controller that determines first-time operations after engine start and limits actuator speeds to prevent sudden movements, using sensors and a key switch to ensure correct operation assignment recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the construction machine allows immediate operation after engine start, then productivity is improved, but the risk of wrong operation increases
Solution Approach 1:
The controller performs preliminary detection of operation lever position and engine state before allowing full operation. The system detects lever operation signals and engine rotation status in advance, then selectively limits actuator speed only for levers operated within a predetermined time after engine start, enabling safe preliminary operation while preventing wrong operations.
2Reliability
If the construction machine limits actuator speed after engine start, then wrong operation is suppressed, but productivity deteriorates
Solution Approach 1:
The speed limitation function is applied locally and selectively rather than uniformly to all operations. The controller identifies which operation lever was operated within the predetermined time after engine start and limits speed only for the corresponding hydraulic actuator, while other actuators can operate at normal speed. This localized application maintains productivity for correct operations while suppressing wrong operations.
3Loss of information
If the construction machine displays operation assignment and requires response operation, then operator awareness is improved, but operation time increases
Solution Approach 1:
The system provides automatic speed limitation based on temporal detection without requiring explicit operator confirmation or response operations. The controller automatically identifies operations performed within the predetermined time after engine start and applies speed limitation accordingly, eliminating the need for manual acknowledgment while still achieving the goal of preventing wrong operations during the critical initial period.
Data Source
AI summary
A construction machine is provided which includes a plurality of hydraulic actuators, a hydraulic pump that discharges pressurized fluid for driving the hydraulic actuators, an engine that drives the hydraulic pump, a plurality of operation lever devices that operate the corresponding hydraulic actuators, a key switch that starts the engine, a speed sensor that senses a rotational speed of the engine, a plurality of operation sensors that sense operation of the corresponding operation lever devices, and a controller that drives, in response to operation of the operation lever devices, the corresponding hydraulic actuators. The controller decides, on the basis of signals from the key switch, the speed sensor, and the plurality of operation sensors, whether operation of the operation lever device is first time operation after start of the engine, and limits, in a case where the operation of the operation lever device is first time operation after start of the engine, the action speed of the hydraulic actuator.