Spherical Link Actuation for Real-Time Forward Transformation
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Solution Overview
Problem
Existing link actuation apparatuses face challenges in achieving accurate positioning and real-time forward transformation due to accumulated calculation errors and time-consuming convolution operations, making real-time processing and long-distance movement from unknown states difficult.
Innovation Solution
A link actuation apparatus with a spherical drive mechanism, featuring a first and second link hub connected by at least three link mechanisms, where each mechanism includes rotatable link members and a central link member, utilizing spherical trigonometry to calculate the position and attitude of the second link hub from angles of the first end link members, enabling real-time forward transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If forward transformation is performed using convolution operations with repetitive calculations, then an approximate solution can be obtained, but calculation time increases significantly making real-time processing difficult
Solution Approach 1:
The patent replaces the mechanical convolution operation system with a spherical coordinate system-based calculation method. By transforming the forward transformation calculation into spherical coordinate calculations, the system achieves both real-time processing capability and high positioning accuracy, eliminating the time-consuming repetitive operations of conventional convolution methods while maintaining computational precision.
2Reliability
If a large number of sums of product of trigonometric functions and inverse trigonometric functions are used in forward transformation, then calculation coverage is comprehensive, but calculation errors accumulate
Solution Approach 1:
The patent changes the calculation parameters from conventional Cartesian coordinate-based trigonometric and inverse trigonometric functions to spherical coordinate-based calculations. This parameter transformation reduces the number of computational steps and eliminates the accumulation of calculation errors that occur with multiple sums of products, while maintaining comprehensive calculation coverage and improving overall reliability.
3Reliability
If the current position is unknown (such as after recovery from abnormality), then the system can recover from abnormal states, but direct teaching or long-distance movement cannot be performed
Solution Approach 1:
The patent implements preliminary action by enabling the system to perform direct teaching and long-distance movement operations even when the current position is unknown. The spherical coordinate calculation method allows the controller to compute target positions and movement paths from any starting state, pre-establishing the capability to handle both abnormality recovery and direct teaching scenarios without requiring prior position knowledge.
Data Source
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AI summary
A link actuation apparatus (50) that actuates a parallel link mechanism (1) where a spherical drive mechanism is constructed includes a controller (100) configured to calculate, based on spherical trigonometry, an attitude of a second link hub (3) from angles βA1 and βA2 that represent the attitude of a first end link member (5) with respect to a first link hub (2) in two of at least three link mechanisms (4). The link actuation apparatus capable of performing forward transformation in real time is thus provided.