Motorized Inclinable Measuring Head With Hirth Couplings
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Solution Overview
Problem
Existing motorized articulated heads for coordinate measuring machines face challenges in precise angular position determination, sensitivity to inertia, and high manufacturing costs due to limited indexation resolution, leading to potential collisions and the need for frequent calibrations.
Innovation Solution
The articulated head features a dual-rotor design with Hirth couplings and a programmable electronic control unit, enabling precise and repeatable indexed positions, reduced sensitivity to inertia, and improved motion control through capacitive sensors and adaptive dynamic modeling, along with a decentralized control system to minimize signal transmission errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional indexing surfaces with finite pins are used to achieve predetermined resting positions, then the device can provide indexed positions, but the manufacturing precision and repeatability are limited due to wear and positioning uncertainty
Solution Approach 1:
The patent replaces traditional mechanical indexing surfaces with finite pins with a continuous circumferential scale and optical encoder system. The scale provides continuous positional information around the rotation axis, while the optical encoder converts this mechanical position into precise digital signals, eliminating wear and positioning uncertainty associated with discrete mechanical indexing elements.
Solution Approach 2:
The invention changes the indexing parameter from discrete angular positions defined by pins to continuous angular position measurement. The circumferential scale divides the rotation into numerous small angular increments, providing fine resolution positioning. This continuous parameter approach allows for much higher precision and repeatability compared to limited discrete indexing points.
2Productivity
If the measuring head is manually actuated, then the structure can be simpler, but the measuring speed decreases and the ability to approach complex surfaces along favorable trajectories is reduced
Solution Approach 1:
The patent implements motorized actuation systems that enable dynamic control of the measuring head's orientation and position. Multiple independent motors control different degrees of freedom, allowing the system to adapt its configuration in real-time to optimize measuring speed and approach complex surfaces along the most favorable trajectories, rather than following fixed manual operation patterns.
Solution Approach 2:
The invention incorporates sensors and control systems that provide feedback on the measuring head's position and orientation. This feedback enables closed-loop control, where the system continuously monitors its state and makes automatic adjustments to maintain optimal measuring conditions, improve speed, and navigate complex geometries effectively.
3Extent of automation
If electromagnetic actuators are used to move indexing surfaces, then automatic orientation is achieved, but the system becomes sensitive to inertia and imbalance, particularly with long extensions
Solution Approach 1:
The patent replaces electromagnetic actuators that directly move heavy indexing surfaces with a system using continuous scales and optical encoders. The measurement of position is decoupled from the actuation mechanism, allowing for more precise control with reduced sensitivity to inertia and imbalance. The optical measurement system can detect position changes without being affected by the mass or balance of moving components.
4Ease of operation
If a centralized external controller is used, then coordination is easier, but signal transmission errors increase and calibration requirements rise
Solution Approach 1:
The patent segments the control system by distributing intelligence to individual components. Each motor and sensor assembly operates with its own local control electronics, processing signals independently before communicating essential data to the central system. This segmentation reduces the volume and complexity of signal transmission, minimizing errors while maintaining coordinated operation through standardized data exchange protocols.
Data Source
AI summary
An articulated measuring head for orienting a probe relatively to a measuring apparatus, including Hirth couplings for providing a high-resolution indexing to two orthogonal rotors and an advanced guiding system to ensure a precise rotation control when the Hirth couplings are free and accurate indexing when they are clamped together. The articulated head of the invention has an embedded dynamic controller using high-precision encoders and crash detection by capacitive sensors.