Comparison of various active impedance control approaches, modeling, implementation, passivity, stability and trade-offs

2012 ◽  
Author(s):  
Mohamad Mosadeghzad ◽  
Gustavo. A. Medrano-Cerda ◽  
Jody. A. Saglia ◽  
Nikos G. Tsagarakis ◽  
Darwin. G. Caldwell
Keyword(s):  
Impedance Control ◽  
Trade Offs ◽  
Active Impedance ◽  
Passivity Stability

scholarly journals Towards versatile legged robots through active impedance control

2015 ◽  
Vol 34 (7) ◽  
pp. 1003-1020 ◽  
Author(s):  
Claudio Semini ◽  
Victor Barasuol ◽  
Thiago Boaventura ◽  
Marco Frigerio ◽  
Michele Focchi ◽  
...  
Keyword(s):  
Impedance Control ◽  
Legged Robots ◽  
Active Impedance

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

Actuators ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 71 ◽  
Author(s):  
Simon Hjorth Jessing Lund ◽  
Peter Billeschou ◽  
Leon Bonde Larsen
Keyword(s):  
Pulse Width Modulation ◽  
Compliant Mechanisms ◽  
Controller Design ◽  
Impedance Control ◽  
Experimental Tests ◽  
Angle Sensor ◽  
High Performing ◽  
High Bandwidth ◽  
Torque Observer ◽  
Active Impedance

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 k Hz and a noise reduction of 13 . 5 (in relation to no observers), at a sample rate and Pulse Width Modulation (PWM) frequency of 25 k Hz . Additionally, experiments verified a precise and high performing controller scheme both during impacts and at a variety of different virtual compliance characteristics.

Active Impedance Control for One-Dimensional Sound

1984 ◽  
Vol 106 (3) ◽  
pp. 393-396 ◽  
Author(s):  
D. Guicking ◽  
K. Karcher
Keyword(s):  
Impedance Control ◽  
Plane Waves ◽  
Normal Incidence ◽  
Frequency Range ◽  
One Dimensional ◽  
Reflected Wave ◽  
Standing Wave Field ◽  
Active Impedance ◽  
Active Sound Absorption ◽  
Active Reflector

Generalizing the concept of active sound absorption, a system for active impedance control has been developed, so far for plane waves at normal incidence. The active reflector is a loudspeaker driven by the incident sound wave. Its feeding signal is derived from a “wave separator” with two microphones splitting up the standing wave field into incident and reflected wave. This system permits easy control of the reflection coefficient and eliminates feedback instability. Arbitrary reflection coefficients between almost 0 and about 1.5 have been realized in the frequency range from below 100 Hz to more than 800 Hz.

scholarly journals Active-Impedance Control of a Lower-Limb Assistive Exoskeleton

2007 ◽  
Author(s):  
Gabriel Aguirre-Ollinger ◽  
J. Edward Colgate ◽  
Michael A. Peshkin ◽  
Ambarish Goswami
Keyword(s):  
Lower Limb ◽  
Impedance Control ◽  
Active Impedance

scholarly journals Robotic Comanipulation With Active Impedance Control

2009 ◽  
Author(s):  
Rui Cortesa˜o ◽  
Brian Zenowich ◽  
Rui Arau´jo ◽  
William Townsend
Keyword(s):  
Impedance Control ◽  
Torque Control ◽  
Task Space ◽  
Control Techniques ◽  
Time Control ◽  
Computed Torque Control ◽  
Position Data ◽  
Active Impedance ◽  
Design Experiments ◽  
Computed Torque

The paper presents active impedance control for robotic comanipulation tasks, enabling virtual contact interactions. Computed torque control in the task space powered by multiple-output active observers (AOBs) is proposed, enhancing haptic perception. Forces and force derivatives are artificially measured from position data around an equilibrium point that can move with time. Control techniques to deal with critical impedances are introduced, taking into account the noise distribution along the system. Stochastic design is discussed. A dynamic model of the redundant lightweight 7-DOF WAM™ arm is derived and evaluated, playing a key role in the control design. Experiments for small and high impedances are presented, highlighting merits and limitations of the approach. A comparative study between active and non-active impedance control is made.

Active impedance control of a knee-joint orthosis during swing phase

2017 ◽  
Author(s):  
Fatima el zahraa Wehbi ◽  
Weiguang Huo ◽  
Yacine Amirat ◽  
Maher El Rafei ◽  
Mohamad Khalil ◽  
...  
Keyword(s):  
Knee Joint ◽  
Impedance Control ◽  
Swing Phase ◽  
Active Impedance
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