Impedance Control and Performance Measure of Series Elastic Actuators

Zhao, Ye; Paine, Nicholas; Jorgensen, Steven Jens

doi:10.1109/tie.2017.2745407

Cited by 53 publications

(30 citation statements)

References 31 publications

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“…having defined: s := σ + ρ 3 , ρ 2 :=ρ 3 and ρ 3 = KB −1 τ f . As expected, an additional derivative of the desired torque is used in this case compared to (10). Moreover, the control law in this section, unlike (10), contains a direct feedback of link acceleration and jerk due to the term Dq in τ d .…”

Section: B Application To Series Elastic Actuatorsmentioning

confidence: 91%

“…Considerations about the stability of the closed-loop system will be drawn in section II-C. It is important to highlight that, unlike other control laws for SEA and VIA, (10) contains no direct feedback of the link acceleration, i.e.q does not directly appear in (10), but only as a dependency of the derivative of the Coriolis matrix inτ d . This is part of the reason why the control law results highly insensitive to the availability ofq in section III.…”

Section: A Actuators With Adjustable Joint Dampingmentioning

confidence: 99%

“…The work presented in [4] is the most closely related to the approach proposed in this paper and the reader is referred to [10], [11] for a review on torque control of SEAs. Nevertheless, although the control law in [4] shares the same objective as in this paper of tracking a desired trajectory for the links, it still suffers from three main shortcomings, which are addressed here.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Joint-Space Impedance Control Using Intrinsic Parameters of Compliant Actuators and Inner Sliding Mode Torque Loop

Garofalo

Werner

Loeffl

et al. 2019

IEEE Control Syst. Lett.

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A new control law for joint-space impedance in robots with variable impedance actuators is presented. The objective is achieved using reduced information on high order derivatives compared to standard approaches, therefore leading to more reliable interactions with unknown environments. Most importantly, the impedance characteristic is given by the real stiffness and damping coefficients of each actuator, therefore updating strategies of the latter directly modify the system response obtained on the link side. The method is evaluated both in simulations and experiments. Additionally, the control law is also adapted for systems with series elastic actuators.

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Section: B Application To Series Elastic Actuatorsmentioning

confidence: 91%

Section: A Actuators With Adjustable Joint Dampingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Joint-Space Impedance Control Using Intrinsic Parameters of Compliant Actuators and Inner Sliding Mode Torque Loop

Garofalo

Werner

Loeffl

et al. 2019

IEEE Control Syst. Lett.

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show abstract

“…Energy storage is another advantage of these actuators, which makes them more efficient. Hence, it is worthwhile to make the actuator "softer" and consequently sacrifice the position control loop bandwidth in order to achieve some desirable properties, such as compliance [26] .…”

Section: Development Of the Snake Robotmentioning

confidence: 99%

Design and Development of a Wheel-less Snake Robot with Active Stiffness Control for Adaptive Pedal Wave Locomotion

et al. 2019

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This paper presents the design and manufacture process of a wheel-less, modular snake robot with Series Elastic Actuators to reliably measure motor torque signal and investigate the effectiveness of active stiffness control for achieving adaptive snake-like locomotion. A Polyurethane based elastic element to be attached between the motor and the links at each joint has been designed and manufactured using water jet cutter, which made the final design easier to develop and more cost-effective, compared to existing snake robots with torque measurement capabilities. The reliability of such torque measurement mechanism examined using simulated dynamical model of pedal wave motion, which proved the efficacy of the design. A distributed control system is also designed, which with the help of an admittance controller, enables active control of the joint stiffness to achieve adaptive snake robot pedal wave locomotion to climb over obstacles, which unlike existing methods does not require prior information about the location of the obstacle. The effectiveness of the proposed controller in comparison to open-loop control strategy has been shown by the number of experiments, which showed the capability of the robot to successfully climb over obstacles with the height of more than 55% of the diameter of the snake robot modules.

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“…An impedance control is widely employed for SEA thanks to its high force control performance, and impedance-controlled SEAs have been used in a variety of applications such as humanoids (e.g., Valkyrie [7], [8], THOR [9], and CoMan [10]), and exoskeletons [11], [12]. Impedance control should be able to achieve high stiffness rendering in addition to lowering impedance.…”

mentioning

confidence: 99%

Passivity Controller Based on Load-Side Damping Assignment for High Stiffness Controlled Series Elastic Actuators

Lee

Ryu

Lee

et al. 2021

IEEE Trans. Ind. Electron.

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This article offers a new insight to the achievable stiffness limitation of the impedance control of series elastic actuators (SEAs) by suggesting a comparative analysis of energy ports and passivity control framework at the energy port to enhance the maximum achievable rendered stiffness of SEAs. To this end, it is explored that SEAs have two different port definitions to assess energy and passivity of the system-spring port and load port; and conservatisms for passivity evaluation of two ports are investigated and compared utilizing frequency characteristics. The results reveal that the load port passivity exhibits less conservatism, which allows to render larger achievable stiffness in impedance-controlled SEAs. Moreover, key parameters that determine the passivity characteristic of the SEA impedance control are discovered based on the load port passivity analysis. A novel passivity control framework that incorporates the time-domain passivity observer and the passivity controller is designed utilizing the load port energy monitoring, which offers a less conservative assessment of the systems passivity. Throughout this novel port passivity analysis and the passivity control, it can be achieved to render maximum rendered stiffness of the SEA impedance control much higher than the limitation that has been perceived as the maximum value.

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Impedance Control and Performance Measure of Series Elastic Actuators

Cited by 53 publications

References 31 publications

Joint-Space Impedance Control Using Intrinsic Parameters of Compliant Actuators and Inner Sliding Mode Torque Loop

Joint-Space Impedance Control Using Intrinsic Parameters of Compliant Actuators and Inner Sliding Mode Torque Loop

Design and Development of a Wheel-less Snake Robot with Active Stiffness Control for Adaptive Pedal Wave Locomotion

Passivity Controller Based on Load-Side Damping Assignment for High Stiffness Controlled Series Elastic Actuators

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