Travel Motor Deceleration Control for Stable Pivot Turns
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Solution Overview
Problem
Conventional working machines experience unexpected deceleration due to their traveling states, such as spin turn, pivot turn, and straight traveling, which can lead to unstable operation.
Innovation Solution
A working machine equipped with left and right traveling motors, rotation detectors, pumps, and a controller that automatically adjusts the speed stages of these motors based on detected rotation speeds and pressures to perform smooth deceleration according to the machine's traveling state, using thresholds and differential pressures to determine when to initiate deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic deceleration is implemented based on operation fluid pressure, then deceleration control is achieved, but unexpected deceleration occurs due to various traveling states
Solution Approach 1:
The controller continuously monitors rotation speeds of both traveling motors and dynamically adjusts deceleration thresholds based on real-time operating conditions. When the rotation speed difference between left and right motors exceeds the adaptive threshold, the controller activates deceleration control, creating a closed-loop feedback system that prevents unexpected deceleration while maintaining automatic control.
Solution Approach 2:
The deceleration threshold is made dynamic rather than fixed, adapting automatically based on the rotation speeds of the traveling motors. The threshold increases with higher rotation speeds and decreases with lower rotation speeds, allowing the system to maintain stable operation across varying traveling states while preserving automatic deceleration functionality.
2Device complexity
If a fixed pressure threshold is used for deceleration judgment, then simple control logic is achieved, but deceleration accuracy deteriorates under different traveling conditions
Solution Approach 1:
The deceleration judgment criterion changes from a fixed pressure threshold to a dynamic threshold based on rotation speed differences. The controller calculates the absolute difference between left and right motor rotation speeds and compares this dynamic value against the threshold, significantly improving deceleration judgment accuracy across different traveling conditions while maintaining relatively simple control logic.
3Productivity
If deceleration is triggered by pressure drop, then automatic speed reduction is achieved, but unintended deceleration occurs during maneuvering
Solution Approach 1:
The system uses feedback from rotation speed sensors on both traveling motors to continuously monitor the speed difference. By comparing this real-time difference against a dynamic threshold, the system accurately distinguishes between normal maneuvering (where speed difference is small) and conditions requiring deceleration (where speed difference exceeds the threshold), preventing unintended deceleration during maneuvering while maintaining automatic speed reduction efficiency.
Solution Approach 2:
The deceleration trigger condition is made dynamic by using rotation speed difference rather than a fixed pressure drop threshold. This dynamic approach adapts to different traveling states, allowing smooth operation during maneuvering when speed difference is minimal while automatically triggering deceleration when the speed difference indicates a need for speed reduction.
Data Source
AI summary
A working machine includes a controller to perform automatic deceleration to automatically reduce a first rotation speed of a left traveling motor to output a power to a left traveling device on a left portion of a machine body and a second rotation speed of a right traveling motor to output a power to a right traveling device on a right portion of the machine body by shifting a speed stage of each of the left and right traveling motors from a second speed to a first speed that is lower than the second speed. The controller is configured or programmed to determine, based on the second rotation speed, a left threshold for judging whether to perform the automatic deceleration in left pivot turn of the machine body, and to determine, based on the first rotation speed, a right threshold for judging whether to perform the automatic deceleration in right pivot turn of the machine body.