Thesis
Torque control of a magnetorheological brake with degrading fluid conditions
Washington State University
Master of Science (MS), Washington State University
2019
Handle:
https://hdl.handle.net/2376/102477
Abstract
Magnetorheological (MR) brakes are used in high performance applications where it is desirable to control the braking torque. The MR-brake contains ferrous materials and as a result exhibits torque hysteresis. This behavior is undesirable as it prevents the braking torque from being controlled accurately and leaves a residual torque in the off-state of the device. An MR-brake was redesigned and used to evaluate two indirect torque control methods (current and inductance) in terms of torque following in the presence of degrading MR fluid conditions. Both control methods require accurate torque-to-input mappings to translate the desired torque profile into an input signal for the control system to follow. To ensure an accurate mapping, the most recent state of the MR-brake must be determined by the control system. MR fluid fill level and aging were found to impact the torque output of the MR-brake, changing the torque-to-input mappings required to maintain good torque following. As a way to identify the brake changes, three identification methods were developed and evaluated as a part of both current and inductance control methods. Across all identification methods, inductance control showed improved torque following over current control. Current measurements are impacted by the resistance of the brake coil and do not provide any insight into the changes occurring in the MR fluid. Inductance measurements are impacted by changes in the MR fluid and can be used to account for changes in the torque output. Through testing it was determined that inductance control using the interpolation identification method to be the most beneficial in terms of maintaining good torque following in the presence of degrading fluid conditions.
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Details
- Title
- Torque control of a magnetorheological brake with degrading fluid conditions
- Creators
- Kevin Michael Wandro
- Contributors
- Hakan Gürocak (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525020401842
- Language
- English
- Resource Type
- Thesis