Low-Level Force-Control of MR-Hydrostatic Actuators
| Autor: | Alexandre Girard, Jean-Sébastien Plante, Jeff Denis |
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| Rok vydání: | 2022 |
| Předmět: |
FOS: Computer and information sciences
0209 industrial biotechnology Control and Optimization Computer science Biomedical Engineering 02 engineering and technology Ball screw law.invention Computer Science - Robotics 020901 industrial engineering & automation 0203 mechanical engineering Artificial Intelligence Control theory law Torque Mechanical Engineering Mobile robot Robot end effector Computer Science Applications Human-Computer Interaction 020303 mechanical engineering & transports Transmission (telecommunications) Control and Systems Engineering Magnetorheological fluid Robot Computer Vision and Pattern Recognition Actuator Robotics (cs.RO) |
| DOI: | 10.48550/arxiv.2207.02671 |
| Popis: | Precise and high-fidelity force control is critical for new generations of robots that interact with humans and unknown environments. Mobile robots, such as wearable devices and legged robots, must also be lightweight to accomplish their function. Hydrostatic transmissions have been proposed as a promising strategy for meeting these two challenging requirements. In previous publications, it was shown that using magnetorheological (MR) actuators coupled with hydrostatic transmissions provides high power density and great open-loop human-robot interactions. Still, the open-loop force fidelity at low and high frequencies are decreased by the transmission's dynamics and by nonlinear friction. This letter compares control strategies for MR-hydrostatic actuator systems to increase its torque fidelity, defined as the bandwidth (measured vs desired torque reference) and transparency (minimizing the undesired forces reflected to the end effector when backdriving the robot). Four control approaches are developed and compared experimentally: (1) Open-loop control with friction compensation; (2) non-collocated pressure feedback; (3) collocated pressure feedback; (4) LQGI state feedback. A dither strategy is also implemented to smoothen ball screw friction. Results show that approaches (1), (2) and (3) can increase the performances but are facing compromises, while approach (4) can simultaneously improve all metrics. These results show the potential of using control schemes for improving the force control performance of robots using tethered architectures, addressing issues such as transmission dynamics and friction. |
| Databáze: | OpenAIRE |
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