On a new generation of torque controlled light-weight robots

Hirzinger, G.; Albu‐Schäffer, Alin; Hähnle, M.; Schaefer, Iris; Sporer, N.

doi:10.1109/robot.2001.933136

Cited by 220 publications

(147 citation statements)

References 10 publications

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“…with r(0) = 0, a diagonal gain matrix K I > 0, and where p(t) is the robot generalized momentum at time t ≥ 0, as defined in (5). Vector r can be computed using the measured (q,q) and the commanded motor torque τ .…”

Section: B Collision Identificationmentioning

confidence: 99%

“…When a collision occurs, the resulting contact forces during the impact phase may be alleviated by pursuing a lightweight robot design [5], by adding soft visco-elastic covering to the links [6], or by introducing compliance in the driving system so as to mechanically decouple the heavy motor inertia from the link inertia [7]- [9]. Light but stiff link materials can be combined with harmonic drives, introducing thus joint elasticity, as in the DLR-III robot manipulator.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Collision Detection and Safe Reaction with the DLR-III Lightweight Manipulator Arm

Luca

Albu‐Schäffer

Haddadin

et al. 2006

2006 IEEE/RSJ International Conference on Intelligent Robots and Systems

590

427

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Abstract-A robot manipulator sharing its workspace with humans should be able to quickly detect collisions and safely react for limiting injuries due to physical contacts. In the absence of external sensing, relative motions between robot and human are not predictable and unexpected collisions may occur at any location along the robot arm. Based on physical quantities such as total energy and generalized momentum of the robot manipulator, we present an efficient collision detection method that uses only proprioceptive robot sensors and provides also directional information for a safe robot reaction after collision. The approach is first developed for rigid robot arms and then extended to the case of robots with elastic joints, proposing different reaction strategies. Experimental results on collisions with the DLR-III lightweight manipulator are reported.

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Section: B Collision Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Collision Detection and Safe Reaction with the DLR-III Lightweight Manipulator Arm

Luca

Albu‐Schäffer

Haddadin

et al. 2006

2006 IEEE/RSJ International Conference on Intelligent Robots and Systems

590

427

View full text Add to dashboard Cite

show abstract

“…There exist only a few examples of purely impedance-controlled legs with internal torque control loop in the literature. Ott et al [26] presented a bipedal walking robot with actuators based on the modular drives of the DLR-Lightweight-Robot-II [17]. These actuator units are based on torque-controlled electric motors with integrated joint torque sensors.…”

Section: Legged Robots With Active Impedancementioning

confidence: 99%

Is Active Impedance the Key to a Breakthrough for Legged Robots?

Semini

Barasuol

Boaventura

et al. 2016

Springer Tracts in Advanced Robotics

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This work addresses the question whether active impedance control is key to a breakthrough for legged robots. In this paper, we will talk about controlling the mechanical impedance of joints and legs with a focus on stiffness and damping control. In contrast to passive elements like springs, active impedance is achieved by torque-controlled joints allowing real-time adjustment of stiffness and damping. We argue that legged robots require a high degree of versatility and flexibility to execute a wide range of assistive tasks to be truly useful to humans and thus to lead to a breakthrough. Adjustable stiffness and damping in realtime is a fundamental building block towards versatility. Experiments with our 80 kg hydraulic quadruped robot HyQ demonstrate that active impedance alone (thus no springs in the structure) can successfully emulate passively compliant elements during highly-dynamic locomotion tasks (running and hopping); and, that no springs are needed to protect the actuation system. Here we present results of a flying trot, also referred to as running trot. To the authors' best knowledge this is the first time a flying trot was successfully implemented on a robot without passive elements such as springs. A critical discussion on the pros and cons of active impedance concludes the paper.

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“…As a selected test for comparing the efficiency of the modified N-E algorithm with respect to the evaluation of symbolically obtained dynamic terms, we have considered one of the series of 7R lightweight robots (LWR) developed at DLR [17]. For this robot, we have computed the matrix C * (q,q) with the NE * algorithm for a given argument q,q, as well as evaluated the symbolic matrix C(q,q) obtained using Christoffel symbols.…”

Section: Numerical Testmentioning

confidence: 99%

“…IV and its properties are analyzed. A comparative numerical test on a 7R lightweight robot by DLR [17] is reported in Sect. V, where the numerical method is evaluated against a Lagrangian approach in terms of computational times.…”

Section: Introductionmentioning

confidence: 99%

A modified newton-euler method for dynamic computations in robot fault detection and control

Luca

Ferrajoli

2009

2009 IEEE International Conference on Robotics and Automation

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Abstract-We present a modified recursive Newton-Euler method for computing some dynamic expressions that arise in two problems of fault detection and control of serial robot manipulators, and which cannot be evaluated numerically using the standard method. The two motivating problems are: i) the computation of the residual vector that allows accurate detection of actuator faults or unexpected collisions using only robot proprioceptive measurements, and ii) the evaluation of a passivity-based trajectory tracking control law. The modified Newton-Euler algorithm generates factorization matrices of the Coriolis and centrifugal terms that satisfy the skew-symmetric property. The computational advantages with respect to numerical evaluation of symbolically obtained dynamic expressions is illustrated on a 7R DLR lightweight manipulator.

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On a new generation of torque controlled light-weight robots

Cited by 220 publications

References 10 publications

Collision Detection and Safe Reaction with the DLR-III Lightweight Manipulator Arm

Collision Detection and Safe Reaction with the DLR-III Lightweight Manipulator Arm

Is Active Impedance the Key to a Breakthrough for Legged Robots?

A modified newton-euler method for dynamic computations in robot fault detection and control

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