Hexapod Error Compensation for Precision Positioning
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Solution Overview
Problem
Hexapods experience precision errors due to geometry and position inaccuracies, affecting their high-precision positioning and movement capabilities in various industrial applications.
Innovation Solution
A method involving a measuring step to determine geometry and position errors, a calculation step to derive error compensation values, and an application step to apply these values to the hexapod's control unit, using three-dimensional measuring devices to assess pivot center positions, jack lengths, and positioning errors, and constructing matrices for error compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hexapod is used for high-precision positioning and movement, then positioning capability is improved, but accuracy errors due to geometry and position inaccuracies worsen positioning precision
Solution Approach 1:
The patent applies preliminary action by performing a calibration procedure before actual use of the hexapod. The system pre-determines geometry errors and position errors of pivot centers, then calculates and stores compensation values in lookup tables. During operation, these pre-calculated compensation values are automatically applied to correct positioning errors, thereby resolving the contradiction between manufacturing precision and measurement precision.
2Measurement precision
If calibration measurements are performed to determine error compensation values, then positioning accuracy is improved, but measurement time and complexity increase
Solution Approach 1:
The calibration measurements and error determination are performed as a preliminary action before the hexapod enters production use. Although this initial calibration requires time and resources, it establishes accurate compensation values that will be automatically applied during subsequent operations, thereby achieving high positioning accuracy without recurring calibration time losses.
Solution Approach 2:
The system implements self-service by automatically applying the pre-calculated compensation values during operation through the control unit. The hexapod system itself performs the error correction without requiring external intervention or repeated calibration procedures, thereby eliminating ongoing time losses while maintaining high positioning accuracy.
Data Source
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AI summary
The invention relates to a method for compensating for accuracy errors of a hexapod (2), said hexapod (2) comprising a base (3), an actuation assembly (4) having six linear translation actuators (5), a control unit (6), and a movable carriage (7) comprising a platform (8) connected to the base (3) by means of the actuation assembly (4). The method includes a measurement step for determining geometry and positioning errors on the hexapod (2), the measurement step including sub-steps for determining positioning errors of the pivot centers on the carriage (7) and on the base (3), for determining length errors of the actuators (5) and for measuring positioning errors of the actuators (5) along the path thereof, the compensation method also including a step for calculating, from measurements taken, error compensation values and a step for applying said error compensation values to the control unit (6) of the hexapod (2), during subsequent use of said hexapod.