Variable Resolution Speed Control for Hydrostatic Transmissions
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Solution Overview
Problem
Self-propelled harvesting machines require manual transmission ratio selection, limiting speed control sensitivity, especially during transport modes or varying terrain, as operators must stop to change ratios.
Innovation Solution
A control unit that automatically adjusts the relation between the desired speed input and propelling speed based on the operator's input, allowing continuous speed control without manual ratio changes, with an acceleration zone for exceeding maximum speeds and adaptive relations for smooth acceleration and deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual transmission ratio selection is used, then the machine can operate in different transmission ratios, but the operator must stop the machine to change ratios, reducing productivity
Solution Approach 1:
The patent implements dynamic transmission ratio selection where the control unit automatically changes transmission ratios based on real-time operating conditions such as ground speed, engine load, and hydraulic pump output. This eliminates the need for manual intervention and allows continuous operation while adapting to varying work requirements, thereby maintaining versatility without sacrificing productivity
2Device complexity
If fixed transmission ratios are used, then the drive system is simpler, but the speed control sensitivity is insufficient during transport mode or varying terrain
Solution Approach 1:
The control unit dynamically adjusts transmission ratio parameters based on operating mode detection. In transport mode, it selects higher transmission ratios for faster speeds, while in work mode, it uses lower ratios for torque multiplication. The system continuously monitors ground speed and automatically transitions between ratios, providing sensitive speed control without requiring complex manual gear selection mechanisms
3Device complexity
If the operating lever has a fixed movement range, then the input mechanism is simpler, but the speed control resolution is insufficient for precise speed adjustment
Solution Approach 1:
The system implements dynamic resolution adjustment where the control unit modifies the relationship between operating lever position and transmission ratio selection based on the current operating mode. In transport mode, the system provides coarser resolution for rapid speed changes, while in work mode, it offers finer resolution for precise speed control. This is achieved through adaptive mapping algorithms that adjust the sensitivity of lever position to transmission ratio changes, providing high precision without requiring a more complex physical input mechanism
Data Source
AI summary
The invention refers to a self-propelled working machine comprising ground engaging means that are in drive connection with an engine for propelling the working machine, a desired speed input means having a range of movement for inputting a desired speed, a control unit receiving a desired speed signal from the desired speed input means and controlling an actuator that is influencing the speed of the ground engaging means based upon the desired speed signal.