Wireless Piezoelectric Sensor for Planter Down Force Measurement
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Solution Overview
Problem
Conventional down force measurement systems for row crop planters are costly and complex due to the need for wiring harnesses, particularly with load sensing pins and strain gages, which complicate real-time down force control during planting operations.
Innovation Solution
A wireless passive piezoelectric pressure sensor embedded in load-carrying wheels of the row unit, transmitting pressure and RFID information, eliminates the need for wiring harnesses and allows for independent adjustment of down force at each row unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load sensing pin with strain gage is used to measure down force, then real-time down force measurement is achieved, but the system cost and complexity increase due to wiring harness requirements
Solution Approach 1:
The patent extracts the sensing function from a complex wired system and embeds it directly into the gauge wheel structure. The strain gage is integrated into the wheel hub or rim, eliminating the need for separate load sensing pins and wiring harnesses, thereby simplifying the overall system while maintaining measurement capability
Solution Approach 2:
The gauge wheel serves multiple functions: it provides structural support for the row unit, carries the seed trench opener, and simultaneously functions as the sensing element for down force measurement. This multi-functionality eliminates the need for separate sensing components and reduces system complexity
2Ease of operation
If conventional strain gage systems with wiring harnesses are used, then down force control is achieved, but the system cost increases
Solution Approach 1:
The patent employs inexpensive strain gage materials and simplified sensing structures that can be easily manufactured and replaced if needed. The integration of sensing elements into the gauge wheel eliminates expensive wiring harnesses and complex load sensing pins, significantly reducing overall system cost
3Force
If down force generators are provided at each row unit linkage mounting, then sufficient down force is applied for seed trench penetration, but the system complexity increases
Solution Approach 1:
The patent combines the down force generation mechanism with the gauge wheel structure itself. The gauge wheel assembly integrates both the load-carrying function and the down force application function, eliminating the need for separate down force generators at each linkage mounting point
Solution Approach 2:
The gauge wheel and its mounting structure are designed to utilize the natural weight of the row unit components to provide the necessary down force. By properly positioning the gauge wheel and utilizing gravitational force, the system achieves sufficient down force without requiring additional active down force generators
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective, real-time down force measurement and control, reducing operational complexity and maintaining optimal seed trench depth and soil compaction without the need for extensive wiring, thus improving planting efficiency.
Implementation Method 1
the pressure sensor is a passive piezoelectric pressure sensor
Implementation Method 2
transmitting both pressure and RFID the information that identifies the particular sensor
Data Source
AI summary
A pressure sensing system for a seeding machine such as a planter to measure the down force on a planter row unit uses a wireless pressure sensor embedded in a load carrying wheel of the row unit. In a preferred embodiment, the pressure sensor is a passive piezoelectric pressure sensor that is a transmitter only, transmitting both pressure and RFID the information that identifies the particular sensor. Multiple sensors may be employed in each wheel and sensors may be employed in more than one wheel of the row unit, such as the gauge wheels on opposite sides of the trench opening disks. The sensors may be made of a PVDF, a known piezoelectric material. A wireless receiver is located on the planter frame or could be located elsewhere to receive the signals from the pressure sensor. A controller determines from the signal, any change in down force and commands the change to a down force generator on the row unit.