11 accepted papers
In this letter, a new robust approach is proposed to address the limitation of impedance rendering for Series Elastic Actuators (SEA). The concept of Elastic Structure Preserving (ESP) control allows for the attachment of desired load-side dynamics to the SEA while maintaining a passivity condition,
This work addresses the problem of global set-point control of elastic joint robots by combining elastic structure preserving (ESP) control with non-collocated integral action. Despite the popularity and extensive research on PID control for rigid joint robots, such schemes largely evaded adoption t
Since safe human-robot interaction is naturally linked to compliance in these robots, this requirement presents a challenge for the positioning accuracy. The class of variable-stiffness robots features intrinsically soft contact behavior where the physical stiffness can even be altered during operat
In situations of harsh impacts, damping injection directly on the link of an articulated soft robot is challenging and usually requires high actuator torques at the moment of impact. In this work, we discuss the underlying reasons and analyze the performance limitations arising in the implementation
The regulation of the link positions of compliant robots, damping out undesired link oscillations while preserving the system's inherent elasticity is still a challenging task in practical applications. This task becomes even harder to be tackled in the case of compliant robots driven by agonistic-a
Like humans or animals, robots with compliant joints are capable of performing explosive or cyclic motions by making systematic use of energy storage and release, and it has been shown that they can outperform their rigid counterparts in terms of peak velocity. For rigid joint robots, there exist we
Air density changes depending on the local atmosphere and affects the rotor thrust of flying robots. This effect has to be compensated by the flight controller in order to realize precise tracking of a desired trajectory. So far, the influence of the air density has been disregarded or only consider
Lightweight robots are known to be intrinsically elastic in their joints. The established classical approaches to control such systems are mostly based on motor-side coordinates since the joints are comparatively stiff. However, that inevitably introduces errors in the coordinates that actually matt…
We present a new approach for Cartesian impedance control of compliantly actuated robots with possibly nonlinear spring characteristics. It reveals a remarkable stiffness and damping range in the experimental evaluation. The most interesting contribution, is the way the desired closed-loop dynamics…
This paper proposes an integration of multi-body and actuator control for multi-contact balancing for robots with highly elastic joints. Inspired by the structure preserving control concept for series-elastic fixed-base robots, the presented approach aims to minimize the control effort by keeping th…
This paper presents a control method to implement trajectory tracking and disturbance rejection characteristics for the link-side dynamics of compliantly actuated robots with nonlinear spring characteristics. This is achieved by introducing new motor coordinates reflecting the damping and feedforwar