Traveling Motor Deceleration Control for Straight-Running Working Machines
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Solution Overview
Problem
Existing working machines, such as skid steer loaders and compact track loaders, face challenges in efficiently managing speed transitions during operation, particularly in determining when to automatically decelerate while traveling straight, as existing systems lack precise thresholds for judging deceleration based on rotation speeds and pressures.
Innovation Solution
The implementation of a controller system that monitors rotation speeds and pressures in both traveling motors, using differential pressures and rotation ratios to determine deceleration thresholds for automatic speed reduction from a second speed stage to a first speed stage during straight traveling, preventing unintentional deceleration during turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If automatic deceleration control is implemented using fixed pressure thresholds, then deceleration response speed is improved, but false deceleration during turns occurs due to pressure changes from turning resistance
Solution Approach 1:
The patent applies dynamics by making the deceleration threshold dynamic rather than fixed. The threshold is adjusted based on the relationship between left and right traveling motor rotation speeds. When the rotation speed difference exceeds a predetermined value (indicating a turn), the threshold is raised to prevent false deceleration. When the rotation speeds are nearly equal (indicating straight travel), the threshold is lowered to enable timely deceleration response.
Solution Approach 2:
The patent changes the parameter of deceleration threshold based on operating conditions. By monitoring rotation speeds of traveling motors and calculating their difference, the system adapts the threshold value to current operational state, thereby distinguishing between pressure changes due to turning versus pressure changes due to load requirements for deceleration.
2Productivity
If deceleration threshold is set low to enable timely deceleration during straight travel, then productivity is improved, but false deceleration during turns increases
Solution Approach 1:
The system dynamically adjusts the deceleration threshold based on real-time rotation speed differences between left and right traveling motors. During straight travel when speed difference is minimal, a low threshold enables timely deceleration for maintaining productivity. During turns when speed difference exceeds the predetermined value, the threshold is automatically raised to prevent false deceleration, ensuring operational stability.
3Device complexity
If pressure-based deceleration control is used without rotation speed consideration, then device complexity is reduced, but measurement precision for determining straight travel vs. turns is insufficient
Solution Approach 1:
The patent makes the existing rotation speed detectors serve a dual function: monitoring traveling speed and detecting turning state. By comparing rotation speeds from detectors already present in the system, the invention determines whether the machine is turning or traveling straight, thereby improving measurement precision without significantly increasing device complexity.
Data Source
AI summary
A working machine includes a first rotation detector to detect a first rotation speed of the left traveling motor, a second rotation detector to detect a second rotation speed of the right traveling motor, and a controller to perform automatic deceleration to automatically reduce the first rotation speed and the second rotation speed both set at respective second speed stages by shifting a speed stage of each of the first rotation speed and the second rotation speed to a first speed stage that is lower than the second speed stage. During straight traveling of a machine body of the working machine, the controller determines a straight-traveling threshold serving as a deceleration threshold for judging whether to perform the automatic deceleration based on the first rotation speed or the second rotation speed.