High-Bandwidth Active Impedance Control of the Proprioceptive Actuator Design in Dynamic Compliant Robotics

Simon Hjorth Jessing Lund*, Peter Billeschou, Leon Bonde Larsen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Dynamic compliant robotics is a fast growing field because of its ability to widen the scope of robotics. The reason for this is that compliant mechanisms may ensure safe/compliant interactions between a robot and an external element—for instance, a human operator. Active impedance control may widen the scope even further in relation to passive elements, but it requires high-bandwidth robust torque and active impedance control which induces high-noise issues even if high-end sensors are used. To address these issues, a complete controller design scheme, including Field-Oriented Control (FOC) of a Brushless Direct Current (BLDC) motor, is proposed. In this paper, controller designs for controlling the virtual impedance, motor torque and field are proposed which enables high-bandwidth robust control. Additionally, a novel speed and angle observer is proposed that aims to reduce noise arising in the angle sensor (typically a 12-bit magnetic encoder) and a Kalman/Luenberger based torque observer is proposed that aims to reduce noise arising in the phase current sensors. Through experimental tests, the combination of the controller designs and observers facilitated a closed-loop torque bandwidth of 2.6 kHz and a noise reduction of 13.5 dB (in relation to no observers), at a sample rate and Pulse Width Modulation (PWM) frequency of 25 kHz. Additionally, experiments verified a precise and high performing controller scheme both during impacts and at a variety of different virtual compliance characteristics.
Original languageEnglish
JournalActuators
Volume8
Issue number4
Number of pages33
ISSN2076-0825
DOIs
Publication statusPublished - 17. Oct 2019

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  • Advanced Computer Systems Group

    Larsen, L. B. & Hallam, J.

    01/01/201801/01/2020

    Project: Research

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