Zero-Turn Control Lever Assembly With Return-to-Neutral Sensing
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Solution Overview
Problem
Hybrid and electric vehicles with zero turn drive systems often lack a reliable return to neutral (RTN) mechanism, which is essential for efficient control and performance, especially when using electric actuators or in conjunction with certain types of vehicles.
Innovation Solution
A speed control assembly that incorporates a return to neutral (RTN) module linked to each operator control lever, utilizing an adjustable linkage and a position sensor module to provide a return force and ensure the vehicle returns to a neutral position when the driving force is no longer applied, improving operator control and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return to neutral (RTN) assembly is used with hydrostatic transmission, then the transmission returns to neutral position when operator stops applying driving force, but this setup is not possible or less desirable in hybrid or electric vehicles with electric actuators
Solution Approach 1:
The patent replaces the traditional mechanical RTN assembly (springs, linkages) with an electronic control system that uses sensors to detect control lever position and an electronic actuator to apply corrective force. This substitution enables the RTN function to work with electric actuators in hybrid and electric vehicles, resolving the incompatibility issue while maintaining the desired return-to-neutral behavior.
2Ease of operation
If an RTN module is linked to each operator control lever with adjustable linkage and position sensor, then operator control and vehicle performance are enhanced, but device complexity increases
Solution Approach 1:
The RTN system is segmented into separate functional modules: position sensors mounted on the control lever, an electronic control unit that processes sensor signals, and an electronic actuator that applies corrective force. This modular segmentation manages complexity by distributing components across different locations and functional domains, making the system more maintainable and adaptable.
Solution Approach 2:
The system continuously monitors control lever position through sensors and uses this feedback information to determine when RTN force is needed. The electronic control unit processes this feedback and activates the actuator only when deviation from neutral position is detected, creating a closed-loop control system that improves ease of operation while managing complexity through intelligent control logic.
Data Source
AI summary
A vehicle control system includes a communication network, a vehicle integration module, and a pair of control assemblies. Each of the pair of control assemblies is configured to be operated by a respective control lever and communicatively connected to the vehicle integration module. Each of the pair of control assemblies comprises an operator control assembly that includes a neutral switch, a return-to-neutral assembly configured to provide a return force to the respective control lever, a return-to-neutral shaft supporting a portion of the return-to-neutral assembly, a magnet attached to the return-to-neutral shaft, a position sensor assembly, and a linkage connecting the operator control assembly to the return-to-neutral assembly. The position sensor assembly includes a circuit board, a magnetic field sensor configured to sense a rotational orientation of the magnet, and a plurality of terminals for communication with the circuit board.