Advances in Mechatronics and Biomechanics towards Efficient Robot Actuation

Editorial

26 March 2019

Editorial: Advances in Mechatronics and Biomechanics Towards Efficient Robot Actuation

Jörn Malzahn

Navvab Kashiri

Monica A. Daley

and

Nikos Tsagarakis

3,393 views

0 citations

Editors

Jörn Malzahn

Italian Institute of Technology (IIT)

Navvab Kashiri

Italian Institute of Technology (IIT)

Nikos Tsagarakis

Italian Institute of Technology (IIT)

Monica A Daley

University of California, Irvine

Impact

A set of typical implementations of compliance in robotic joints, with main pros and cons shown in green and red respectively.

Review

11 December 2018

An Overview on Principles for Energy Efficient Robot Locomotion

Navvab Kashiri

, 22 more and

Nikos Tsagarakis

Despite enhancements in the development of robotic systems, the energy economy of today's robots lags far behind that of biological systems. This is in particular critical for untethered legged robot locomotion. To elucidate the current stage of energy efficiency in legged robotic systems, this paper provides an overview on recent advancements in development of such platforms. The covered different perspectives include actuation, leg structure, control and locomotion principles. We review various robotic actuators exploiting compliance in series and in parallel with the drive-train to permit energy recycling during locomotion. We discuss the importance of limb segmentation under efficiency aspects and with respect to design, dynamics analysis and control of legged robots. This paper also reviews a number of control approaches allowing for energy efficient locomotion of robots by exploiting the natural dynamics of the system, and by utilizing optimal control approaches targeting locomotion expenditure. To this end, a set of locomotion principles elaborating on models for energetics, dynamics, and of the systems is studied.

38,141 views

81 citations

RMS of active muscle activations in three modes using OIC (solid fill) and SOIC (crosshatch fill). Circled numbers are corresponding to the active muscle numbers.

Original Research

01 November 2018

Configuration-Dependent Optimal Impedance Control of an Upper Extremity Stroke Rehabilitation Manipulandum

Borna Ghannadi

, 1 more and

John McPhee

4,004 views

11 citations

Review

17 October 2018

Linking Gait Dynamics to Mechanical Cost of Legged Locomotion

David V. Lee

and

Sarah L. Harris

8,941 views

12 citations

The human motor control system is highly suitable as model for robot modeling and control. The nervous system is responsible for cognition, planning, and controlling actions, while the musculatory system delivers power to generate movement supported by the skeletal system. This corresponds to a high-level and lower-level controller in a robotic system that control actuators to manipulate a mechanism.

Original Research

08 October 2018

A General Approach to Achieving Stability and Safe Behavior in Distributed Robotic Architectures

Stefan S. Groothuis

, 1 more and

Stefano Stramigioli

3,690 views

8 citations

Hip actuation experiment, using frequencies of 0.15 and 0.05 Hz: Joint angular position (JAbsP on graph) and motor position (MPD) vs. Time.

Original Research

11 September 2018

Evaluation and Analysis of Push-Pull Cable Actuation System Used for Powered Orthoses

Svetlana Grosu

, 3 more and

Dirk Lefeber

15,100 views

13 citations

(A) Upper bound of degrees of freedom for tendon/sheath system described above. (B) Corresponding minimum achievable bend radius for sheath system.

Hypothesis and Theory

18 June 2018

Efficiency and Power Limits of Electrical and Tendon-Sheath Transmissions for Surgical Robotics

Christopher R. Wagner

and

Evangelos Emmanouil

3,458 views

1 citations

(A) Sinusoidal analysis of skinned mouse cardiac muscle fibers shows an active perturbation response qualitatively similar to a Maxwell-type material for frequencies above 10 Hz. A parallel elastic response dominates at lower frequencies, and the active component is no longer evident. Data replotted from Palmer et al. (2007). (B) plot: The viscoelastic perturbation response for a Maxwell-type material where τrelax is the timescale of stress relaxation, K is the dynamic modulus of the muscle, and ω is the frequency of a sinusoidal perturbation. Against perturbations with periods shorter than τrelax, the response resembles an elastic solid, and it resembles a viscous fluid for slower perturbations. inset: If the relaxation time for the active perturbation response of a sarcomere depends on its neural input u, we hypothesize that the sarcomere may switch between solid and fluid behaves by varying u. For example, the active perturbation response may be fluid-like at low neural input (green) and solid-like at high neural input (red). (C) For the hypothesized dependence τrelax∝ud-1 (Equation 6), τrelax is increasing with increasing u if d > 1, invariant with u if d = 1, and decreasing with increasing u if d < 1. Each case results in different functional consequences for a sarcomere and ultimately for muscles when coupled with the fact that a sarcomere's active tension Fa increases with u. A sarcomere can vary between a solid behavior with high active tension (mechanically stable against external perturbations, green shading) and a fluid behavior with low active tension (freely yields with minimal resistance, brown shading) only if d > 1.

Mini Review

14 June 2018

Active Viscoelasticity of Sarcomeres

Khoi D. Nguyen

, 1 more and

Madhusudhan Venkadesan

5,171 views

15 citations

Original Research

14 June 2018

Highly-Integrated Hydraulic Smart Actuators and Smart Manifolds for High-Bandwidth Force Control

Victor Barasuol

, 7 more and

Claudio Semini

Hydraulic actuation is the most widely used alternative to electric motors for legged robots and manipulators. It is often selected for its high power density, robustness and high-bandwidth control performance that allows the implementation of force/impedance control. Force control is crucial for robots that are in contact with the environment, since it enables the implementation of active impedance and whole body control that can lead to a better performance in known and unknown environments. This paper presents the hydraulic Integrated Smart Actuator (ISA) developed by Moog in collaboration with IIT, as well as smart manifolds for rotary hydraulic actuators. The ISA consists of an additive-manufactured body containing a hydraulic cylinder, servo valve, pressure/position/load/temperature sensing, overload protection and electronics for control and communication. The ISA v2 and ISA v5 have been specifically designed to fit into the legs of IIT’s hydraulic quadruped robots HyQ and HyQ-REAL, respectively. The key features of these components tackle 3 of today’s main challenges of hydraulic actuation for legged robots through: (1) built-in controllers running inside integrated electronics for high-performance control, (2) low-leakage servo valves for reduced energy losses, and (3) compactness thanks to metal additive manufacturing. The main contributions of this paper are the derivation of the representative dynamic models of these highly integrated hydraulic servo actuators, a control architecture that allows for high-bandwidth force control and their experimental validation with application-specific trajectories and tests. We believe that this is the first work that presents additive-manufactured, highly integrated hydraulic smart actuators for robotics.

34,111 views

55 citations