Session WedAT1 Pegaso A Wednesday, October 10, 2012 ... - Lirmm

Session WedFT11 Hidra Wednesday, October 10, 2012, 16:15–17:30
Robots with Variable Impedance Actuation
Chair Raffaella Carloni, Univ. of Twente
Co-Chair Alin Albu-Schäffer, DLR - German Aerospace Center
16:15–16:30 WedFT11.1
A Simple Controller for a Variable Stiffness Joint
with Uncertain Dynamics and Prescribed
Performance Guarantees
Efi Psomopoulou, Zoe Doulgeri and George A. Rovithakis
Dept of Electrical & Computer Eng., Aristotle University of Thessaloniki, Greece
Nikos G. Tsagarakis
Department of Advanced Robotics, Istituto Italiano di Tecnologia, Italy
• The CompAct-VSA joint is considered.
• Transient and steady state performance
for link q and stiffness motor position
θ k is a priori specified and guaranteed.
• A full state feedback tracking controller
is proposed without requesting any
knowledge of system nonlinearities.
• Simulation results in a trajectory
following task (figure) satisfy preset
performance with reasonable control
effort (max voltage 24 V)
• The stiffness motor desired trajectory
corresponds to a stiffness variation
between the values of 170-582 Nm/rad.
16:45–17:00 WedFT11.3
Limit Cycles and Stiffness Control with Variable
Stiffness Actuators
Raffaella Carloni
Dept. Electrical Engineering, University of Twente, Italy
Lorenzo Marconi
Dept. Electronics, Computer Science and Systems, University of Bologna, Italy
• The inherent compliance of variable
stiffness actuators is exploited to
obtain a robust and energy-efficient
behavior
• The proposed control strategy
guarantees a robust tracking of a limit
cycle trajectory and of a desired
stiffness for the actuator’s load
• Experimental tests on the vsaUT-II
validate the control design
17:15–17:30 WedFT11.5
Rigid vs. Elastic Actuation: Requirements &
Performance
S. Haddadin, N. Mansfeld, A. Albu-Schäffer
Robotics and Mechatronics Center
This paper answers following questions
1)How does geometric scaling (i.e.
systematic mass variation) influence the
performance of a rigid joint?
2)What are the requirements for an elastic
joint that consists of a smaller motor and
an elastic transmission in order to reach at
least the maximum velocity of the rigid
manipulator with equivalent overall mass?
16:30–16:45 WedFT11.2
On the Control of Redundant Robots
with Variable Stiffness Actuation
Gianluca Palli and Claudio Melchiorri
Dipartimento di Elettronica, Informatica e Sistemistica, Università di Bologna
Viale Risorgimento 2, 40136 Bologna, Italy
email: {gianluca.palli, claudio.melchiorri}@unibo.it
• The control of redundant manipulator
with variable stiffness actuation is
discussed
• An output-based control approach is
adopted
• The actuators dynamics is decoupled
from the arm dynamics by means of
a singular perturbation approach
• The designed controller presents
several advantages with respect to
previously proposed state-feedback
controllers
• The theoretical results are valideted
by simulation of a three DOF planar
manipulator
2012 IEEE/RSJ International Conference on Intelligent Robots and Systems
–179–
Working principle scheme of a VSA.
17:00–17:15 WedFT11.4
On Impact Decoupling Properties of Elastic
Robots and Time Optimal Velocity Maximization
on Joint Level
S. Haddadin, K. Krieger, N. Mansfeld, A. Albu-Schäffer
Robotics and Mechatronics Center
This paper answers following questions
1) What are suitable reflected stiffness and
inertias for achieving impact decoupling and
how is the maximum collision force affected
by these?
2) How does the most important real-world
state constraint for elastic joints, the
maximum deflection, affect the optimal
excitation (execution of explosive motion)
of the mechanism?