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Precise Position Control of Holonomic Inchworm Robot Using Four Optical Encoders
Kengo Tanabe1, Masato Shiota1, Eiji Kusui1
1Department of Mechanical Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 2408051, Kanagawa, Japan.
Micromachines
|February 25, 2023
Summary
This study introduces a compact XYθ position sensor for precise control of holonomic inchworm robots. The novel sensor achieves centimeter to submicrometer positioning accuracy, enabling advanced robotic applications.
Area of Science:
- Robotics and Control Systems
- Precision Engineering
- Optical Metrology
Background:
- Precise positioning is crucial for holonomic robots in applications like microscopy and multi-tool manipulation.
- Existing sensors often lack the required compactness or multi-axis precision for small-scale robots.
Purpose of the Study:
- To design and validate a compact XYθ position sensor for precise, wide-range control of holonomic inchworm robots.
- To enable simultaneous measurement of X, Y, and θ displacements using a novel integrated scale and optical encoders.
- To demonstrate closed-loop control capabilities for complex trajectories and high-resolution positioning.
Main Methods:
- Designed a compact XYθ position sensor utilizing four optical encoders and an integrated two-degrees-of-freedom scale.
- Developed a calibration equation to mitigate crosstalk errors between the XYθ axes.
- Implemented closed-loop control for star-shaped trajectories and simultaneous three-axis PID control for micrometer-scale movements.
Main Results:
- Demonstrated precise closed-loop control of a holonomic robot across centimeter to submicrometer ranges.
- Achieved sub-micrometer and sub-millidegree resolution in trajectory analysis within a MHz measurement cycle.
- Validated the sensor's capability for simultaneous multi-axis control and complex motion sequences.
Conclusions:
- The developed XYθ position sensor is a viable solution for precise, wide-range control of holonomic robots.
- This technology facilitates advanced robotic operations in confined spaces, such as within instruments and microscopes.
- It represents a significant advancement for applications requiring coordinated, high-precision multi-tool manipulation.
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