Clutch Speed-Difference Torque Estimation in Tractor Drivelines
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Solution Overview
Problem
Existing methods for determining torque in the drive train of agricultural towing vehicles are complex and require expensive torque sensors.
Innovation Solution
A method using two rotational speed sensors to capture drive-side and output-side rotational speeds, controlling the clutch to create a rotational speed difference, and determining the torque based on this difference and a predetermined limit value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors are used to determine torque in the drive train, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses rotational speed sensors as intermediary devices to indirectly measure torque. Instead of directly measuring torque with complex torque sensors, the system measures rotational speeds on both sides of the clutch and calculates torque from the speed difference, using the clutch's mechanical properties as a mediator to convert an unmeasurable quantity (torque) into measurable quantities (rotational speeds).
Solution Approach 2:
The patent replaces the mechanical torque sensing system with an electrical/electronic measurement system. By using rotational speed sensors and electronic calculation based on the relationship between clutch torque and speed difference, the system substitutes complex mechanical torque measurement with simpler electrical measurements and computational analysis.
2Measurement precision
If torque sensors are used to determine torque in the drive train, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent employs inexpensive rotational speed sensors instead of expensive torque sensors. The system uses multiple low-cost speed sensors whose data is processed through calculation to achieve torque measurement, replacing a single high-cost torque sensor with multiple low-cost sensors and computational processing.
Solution Approach 2:
The patent uses the clutch's mechanical characteristics as an intermediary to enable torque measurement through cheaper means. By leveraging the known relationship between clutch torque and rotational speed difference, the system uses the clutch itself as a mediator to convert expensive direct torque measurement into cheaper indirect measurement through speed sensing.
3Device complexity
If rotational speed difference is used to determine torque, then device complexity is reduced, but measurement precision may be affected
Solution Approach 1:
The system continuously monitors the rotational speeds on both sides of the clutch and uses this feedback to calculate torque in real-time. By establishing a feedback loop that continuously measures speed difference and updates torque determination, the system maintains measurement precision while using a simpler device configuration compared to direct torque sensing.
Solution Approach 2:
The patent establishes predetermined relationships and calibration data between clutch characteristics and torque before actual operation. By pre-characterizing the clutch's torque-speed relationship and storing this information for later use in calculations, the system prepares measurement parameters in advance, ensuring precision is maintained when torque is determined from rotational speed differences during operation.
Data Source
AI summary
A method for determining a torque acting at a position of a drive train of an agricultural towing vehicle, includes controlling a clutch of the drive train between a closed state and an open state, capturing a drive-side rotational speed at the clutch via a first rotational speed sensor, capturing an output-side rotational speed at the clutch via a second rotational speed sensor, controlling the clutch in the direction of the open state, determining, during controlling the clutch, a difference between the rotational speeds on the drive and output sides, comparing the difference with a predetermined difference limit value, capturing the value of a physical variable that causes the clutch control on the basis of the comparison result, and determining the torque on the basis of the captured value of the physical variable.