Design and performance of a thermal actuator driving a preloaded linear translation stage
A thermally actuated, single-axis, bidirectional translation stage is designed and constructed. To increase the temperature of the thermal actuator, induction heating is used while air-water-mist cooling is used to decrease the temperature. An automated control strategy comprising PID closed loop co...
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| Published in: | Precision engineering Vol. 71; pp. 187 - 199 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier Inc
01-09-2021
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | A thermally actuated, single-axis, bidirectional translation stage is designed and constructed. To increase the temperature of the thermal actuator, induction heating is used while air-water-mist cooling is used to decrease the temperature. An automated control strategy comprising PID closed loop control (for heating) and On/Off switching between air and mist control (for cooling) is described. The translation stage of this study produces a displacement range of 100 μm and 200 μm (using 240 W and 480 W power sources) in the presence of preloads up to 1 kN. Dependent on the power source used, the root mean square (rms) controller error at steady-state is within 15 nm (240 W) and 35 nm (480 W). No significant variation in the rms controller error was measured in the presence of the different preloads. Dynamic performance is evaluated from step responses over the full range of the actuator as well closed-loop frequency responses. The non-linear, asymmetric aspects of heating and cooling are discussed. Further observations of the system behavior and the preload effect are presented with discussion covering the slew rate, magnitude of overshoot, and controller settling time.
•Presents calculation of the eddy current density and induced eddy current power in a cylindrical aluminum tube.•A zero-voltage-switching circuit is evaluated using PWM control signal for delivering the power to the thermal actuator.•Experimental tests show the actuator provides a range of 200 µm and the steady state controller error is within ±70 nm.•The steady state controller error and the dynamic response of the system is maintained for preloads up to 1 kN.•Combining water and air-mist for cooling improved the symmetry of the control and the dynamic response. |
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| ISSN: | 0141-6359 1873-2372 |
| DOI: | 10.1016/j.precisioneng.2021.03.003 |