Articulated Work Machine Steering Control for Fast Bending Response
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Solution Overview
Problem
Existing work machines face issues with poor followability of bending motion during steering operations due to varying engine rotation speeds affecting hydraulic fluid flow rates, leading to inefficient fuel consumption and operational lag.
Innovation Solution
A work machine system that controls the engine rotation speed based on steering commands to adjust hydraulic fluid flow rates to the steering cylinders, using a controller to manage engine speed and fluid flow in response to operator input, thereby improving followability and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the hydraulic pump displacement is designed to be large to ensure minimum flow rate at low engine speed, then the followability of bending motion is improved, but fuel consumption deteriorates at high engine speed
Solution Approach 1:
The hydraulic pump displacement is made variable rather than fixed. The control unit adjusts the pump displacement dynamically based on engine speed and steering operation state, allowing the system to adapt to different operating conditions. This resolves the contradiction by enabling high displacement at low engine speed for good followability while maintaining low displacement at high engine speed for fuel efficiency.
Solution Approach 2:
The system changes the physical parameter of pump displacement based on operating conditions. By detecting engine speed and steering operation state, the control unit adjusts the pump displacement parameter to match actual需求的, thereby improving followability when needed while reducing fuel consumption when not needed.
2Use of energy by moving object
If the engine rotation speed is controlled to be low to reduce fuel consumption, then fuel efficiency is improved, but the followability of bending motion deteriorates
Solution Approach 1:
The system dynamically adjusts pump displacement based on engine speed and steering operation state. When engine speed is low but steering operation requires high flow rate, the pump displacement is increased to maintain followability. This allows the engine to operate at fuel-efficient low speeds while still delivering the required hydraulic flow through increased pump displacement.
Solution Approach 2:
The pump displacement parameter is changed in response to engine speed and steering operation state. This parameter adjustment compensates for the reduced engine speed, ensuring that the hydraulic flow rate remains sufficient for good followability even when the engine operates at low speeds for fuel efficiency.
3Ease of operation
If the hydraulic pump discharge flow rate is increased to improve followability, then the bending motion responsiveness is improved, but fuel consumption increases
Solution Approach 1:
The pump displacement is dynamically adjusted based on actual steering operation state and engine speed. The control unit increases pump displacement only when steering operation requires high flow rate, and decreases it when steering operation is light or engine speed is already high. This dynamic adjustment ensures good followability when needed while minimizing fuel consumption during normal operation.
Solution Approach 2:
The system changes the pump displacement parameter according to steering operation state and engine speed. By detecting when high flow rate is actually needed for steering responsiveness, the system adjusts the displacement parameter to provide high flow rate only during such periods, thereby improving followability without continuously increasing fuel consumption.
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
Enhances the responsiveness of the bending motion to steering operations while optimizing fuel efficiency by matching hydraulic fluid supply to operational demands.
Implementation Method 1
a hydraulic pump that supplies hydraulic fluid to the steering cylinder
Implementation Method 2
Hydraulic fluid discharged from the hydraulic pump is supplied to the steering cylinder. The steering cylinder extends and contracts thereby turning the front frame with respect to the rear frame
Data Source
AI summary
A second frame is turnably connected to a first frame. A steering cylinder is connected to the second frame and the first frame. The steering cylinder causes the second frame to turn with respect to the first frame. A hydraulic pump supplies hydraulic fluid to the steering cylinder. An engine drives the hydraulic pump. A steering operating member is operable by an operator. A steering operation sensor outputs a steering command signal corresponding to an operation of the steering operating member. A controller controls a flow rate of the hydraulic fluid supplied from the hydraulic pump to the steering cylinder by controlling a rotation speed of the engine in accordance with the steering command signal.