Capacitive Sensor Angle Measurement for Pivot Displacement
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Solution Overview
Problem
Conventional angle measurement apparatus, such as theodolites and laser trackers, face challenges with pivot mounting due to limited directional loading in V-bearings, which complicates non-perpendicular setup and motor drive, and stressed ball bearings that lose ideal rolling due to excessive stress and temperature influences.
Innovation Solution
The apparatus employs a rotatable telescope body with dual bearing locations and capacitive sensor arrangements to detect pivot displacement perpendicular to the axial direction, allowing normal tensioning of ball bearings for easy rolling and accounting for bearing inaccuracies and temperature corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If V-bearings are used for pivot mounting, then the structure is simple, but the bearing can only be loaded in one direction which prevents non-perpendicular setup and complicates motor drive
Solution Approach 1:
The pivot mounting is divided into multiple bearing locations (at least two) spaced along the pivot axis. Each bearing location independently supports the pivot, allowing the system to accommodate loads from multiple directions and enabling non-perpendicular setup while maintaining structural simplicity
Solution Approach 2:
The bearing system is designed to handle multiple loading directions simultaneously. By distributing bearing locations along the pivot and using sensor arrangements to detect displacements in orthogonal directions, the system becomes adaptable to various setup configurations and drive directions
2Measurement precision
If stressed ball bearings are used to minimize radial play, then radial deviation error is reduced, but the balls cannot roll ideally due to excessive stress and temperature complications arise
Solution Approach 1:
The mechanical stress-based positioning is replaced with a sensor-based detection system. Capacitive sensors measure the actual position of the pivot with high precision without requiring excessive mechanical stress on the ball bearings, allowing the balls to roll ideally while maintaining measurement accuracy through electronic compensation
Solution Approach 2:
The system changes from relying on mechanical parameters (ball stress) to electrical parameters (capacitive sensor measurements). By measuring pivot position electrically and computationally correcting the viewing direction, the system achieves high precision without compromising ball bearing rolling performance or introducing temperature-related complications
3Measurement precision
If multiple sensor arrangements are added to detect pivot displacement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses two measurement locations spaced along the pivot axis, adding an axial dimension to the measurement. This allows detection of pivot displacement in three-dimensional space (two orthogonal directions at each location), improving measurement precision while maintaining manageable complexity through systematic sensor placement
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 angle measurement by decoupling position evaluations in orthogonal directions, ensuring accurate viewing direction determination and correcting for pivot position, while maintaining low stress on ball bearings and minimizing temperature effects.
Implementation Method 1
At least one of the sensor arrangements comprises a group of capacitive sensors, which at the measurement location, detect a displacement of the pivot in directions perpendicular to the axial direction
Data Source
AI summary
An angle measuring device for optical angle measurement has a telescope body 5 which is rotatably mounted around at least one shaft (1, 2; 11), wherein the shaft (1, 2; 11) is rotatably mounted at least two bearing points 6, and the bearing points 6 are at a distance from one another in the direction of the shaft (1, 2; 11). In this case, at least two sensor arrangements for detecting the position of the shaft (1, 2; 11) are respectively arranged at a measurement point along the shaft (1, 2; 11), wherein the measurement points are at a distance from one another in the direction of the shaft (1, 2; 11). At least one of the sensor arrangements has a group of capacitive sensors (7a, 7b, 7c, 7d) which detect a displacement of the shaft (1, 2; 11) in directions perpendicular to the axial direction at the measurement point.