Pneumatic Piston Position Sensing Without a Reference Pass
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Solution Overview
Problem
Existing methods for determining the position of a pneumatic piston or wheel in pneumatic drive and gripper systems are either imprecise or require complex and costly solutions, especially after a power-off or system restart, and often necessitate a reference pass.
Innovation Solution
A method that combines a precise but relative angle signal from a single-turn magnetic field sensor with imprecise but absolute angle information to determine the unique and precise position of the piston or wheel without the need for a reference pass or complex multi-turn rotary encoders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-turn magnetic field sensor is used to detect the angle of rotation, then the device complexity and cost are reduced, but the position determination becomes ambiguous after multiple rotations
Solution Approach 1:
The patent combines a single-turn magnetic field sensor (providing precise periodic angle information) with a model-based position determination system (providing absolute position context) to achieve unambiguous position determination across multiple rotations without using a complex multi-turn encoder
Solution Approach 2:
The patent introduces a model-based calculation as an intermediary that uses the periodic sensor signal combined with system parameters (gear ratio, piston stroke, initial position) to determine the absolute position, thereby resolving the ambiguity of the single-turn sensor across multiple rotations
2Measurement precision
If a multi-turn rotary encoder is used to determine position unambiguously, then the position determination accuracy is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent replaces the expensive multi-turn rotary encoder with a combination of a simple single-turn magnetic field sensor and a computational model, achieving the same functional result at lower cost and complexity
Solution Approach 2:
The patent substitutes a mechanical/multi-turn sensing system with a single-turn sensor combined with a model-based calculation system, using computational methods to achieve what would otherwise require complex hardware
3Measurement precision
If a reference pass is performed to establish initial position, then the position determination accuracy is improved, but the productivity and time to usability are reduced
Solution Approach 1:
The patent performs preliminary configuration by storing the initial position (zero point) in memory during system setup or first operation, eliminating the need for repeated reference passes after power-off and enabling immediate accurate position determination
Solution Approach 2:
The system uses its own operational data and stored initial position to continuously determine the current position without requiring external reference passes or manual intervention, making the position determination self-sufficient
4Measurement precision
If a reference pass is performed to establish initial position, then the position determination accuracy is improved, but the reliability is reduced due to potential collisions and workpiece loss
Solution Approach 1:
The patent performs the reference action during initial system setup or first operation, storing the zero point position in memory, thereby eliminating the need for repeated reference passes that could cause safety issues during normal operation
Solution Approach 2:
The patent converts the potential harm of reference passes (collisions, workpiece loss) into a one-time initial configuration step, after which the system operates safely without requiring repeated reference passes
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
This solution enables precise and unique determination of the piston or wheel position, reducing costs and eliminating the need for reference passes, while maintaining high precision even after system restarts.
Implementation Method 1
an angle-of-rotation sensor, in particular a single-turn magnetic field sensor
Data Source
AI summary
A method and device for determining a piston or wheel position in a pneumatic drive and/or gripper system, comprising a wheel/piston arrangement which has a wheel and a piston coupled to the wheel. The method for determining a piston or wheel position in a pneumatic drive and/or gripper system may have a plurality of steps. In a first step, a defined system stimulus of the pneumatic drive and/or gripper system is triggered. In a further step, a system response of the pneumatic drive and/or gripper system is detected as a reaction to the defined system stimulus. Furthermore, it is provided that a parameter dataset is received. Furthermore, the piston or wheel position is determining by performing a position calculation prescription, on the basis of the detected system response, using the received parameter dataset and a comparison against the periodic, non-unique angle-of-rotation signal.