31 accepted papers
Model-Mediated Teleoperation (MMT) is a form of teleoperation where a model is used to display operator commands to the environment and environmental feedback to the operator. This circumvents the performance-stability trade-off to which many other teleoperation methods are prone under high time del
In Total Knee Replacement Arthroplasty (TKA), surgical robotics can provide image-guided navigation to fit implants with high precision. Its tracking approach highly relies on inserting bone pins into the bones tracked by the optical tracking system. This is normally done by invasive, radiative mann…
In breast cancer patients, some nodules are only visible on MRI, thus, requiring MRI-guidance to perform the biopsy. MRI interventions are cumbersome due to the magnetic field and the constrained working space. An MR safe robotic system actuated by pneumatic stepper motors may enable these procedure…
Absolute position detection in sensorless electric stepper motors potentially allows for higher space efficiency, improved shock resistance, simplified installation, reduced number of parts and lowered cost. A prototype is demonstrated measuring 42 × 42 × 34 mm3 with seven coils arranged in a star c…
We present an optimization-based structural-parametric synthesis method for reconfigurable closed-chain underactuated linkages for robotic systems that physically interact with the environment with an emphasis on adaptive grasping. The key idea is to implement morphological computation concepts to k…
One way to create a quadruped galloping robot from scratch is to design a brick-shaped body and utilize relatively simple open-chain leg mechanisms controlled with relatively complex control algorithms. Alternatively, we can look at how nature solved the same task designing fast mammals such as chee…
Reinforcement learning algorithms have proven to be capable of solving complicated robotics tasks in an end-to-end fashion without any need for hand-crafted features or policies. Especially in the context of robotics, in which the cost of real-world data is usually extremely high, Reinforcement Lear…
Multi-axis stepper motors offer a compact solution to actuate multiple degrees of freedom in a mechanical system by a single device. This research presents an electric stepper motor with three coaxial shafts driven by a single stator. The motor dimensions are 42 × 42 × 44 mm$^3$ (excluding output sh
We address the problem of motion control for safe physical interaction, and in particular finding new ways for impedance controller parameters’ adaptation to ensure better safety with minimum possible lose in robot performance. We propose an exteroception-based dynamically updated safety metric that…
For the study of highly nonlinear, conservative dynamic systems, finding special periodic solutions which can be seen as generalization of the well-known normal modes of linear systems is very attractive. However, the study of low-dimensional invariant manifolds in the form of nonlinear normal modes
To this day, most robots are installed behind safety fences, separated from the human. New use-case scenarios demand for collaborative robots, e.g. to assist the human with physically challenging tasks. These robots are mainly installed in work-environments with limited space, e.g. existing producti…
This work presents the concept of energy-based safety for series-elastic actuation. Generic actuation passivity and safety is treated, defining several energy storage and power flow properties related to passivity. Safe behaviour is not guaranteed by passivity, but can be guaranteed by energy and po…
Modern robots act in dynamic and partially unknown environments where path replanning can be mandatory if changes in the environment are observed. Task-prioritized control strategies are well known and effective solutions to ensure local adaptation of robot behaviour. The highest priority in a stack…
The integration of computer vision techniques for the accomplishment of autonomous interaction tasks represents a challenging research direction in the context of aerial robotics. In this paper, we consider the problem of contact-based inspection of a textured target of unknown geometry and pose. Ex…
In this work, we show how the interactive behavior of an aerial robot can be modeled and controlled effectively and elegantly in the port-Hamiltonian framework. We present an observer-based wrench/impedance controller for a fully-actuated hexarotor. The analysis and control are performed in a geomet…
Pneumatic rotational stepper motors can be used to actuate MR (magnetic resonance) safe robotic systems. This paper describes novel techniques to minimize the volumetric size and/or step size of such motors in order to cope with the limited space requirements while still delivering high precision. T…
In this work, we approach the control problem of fully-actuated UAVs in a geometric port-Hamiltonian framework. The UAV is modeled as a floating rigid body on the special Euclidean group SE(3). A unified near-hovering motion and impedance controller is derived by the energy-balancing passivity-based
The biomimetic approach in robotics is promising: nature has found many good solutions through millions of years of evolution. However, creating a design that enables fast and energy-efficient locomotion remains a major challenge. This paper focuses on the development of a full leg mechanism for a f…
Cardiovascular diseases remain as the most common cause of death worldwide. Remotely manipulated robotic systems are utilized to perform minimally invasive endovascular interventions. The main benefits of this methodology include reduced recovery time, improvement of clinical skills and procedural f…
This paper presents the autonomous battery exchange operation for small scale UAVs, using a mobile ground base that carries a robotic arm and a service station containing the battery exchange mechanism. The goal of this work is to demonstrate the means to increase the autonomy and persistence of rob…
In contexts where robots share their workspace with humans, safety is of utmost importance. Consequently, in recent years, a big impulse has been given to the design of human-friendly robots by involving both mechanical and control design aspects. Regarding controller design, this often involves int
In breast cancer detection it is essential to perform precise interventions to determine the diagnosis. Robotic systems actuated by MR safe pneumatic stepper motors could improve accuracy to target the tumor. The achievable accuracy or speed is limited due to long pneumatic tubes connecting the moto…
Safety is essential for robots in unknown environments, especially when there is physical Human-Robot Interaction (pHRI). Control over energy, or passivity, is an effective safety mechanism. However, when the control algorithm is implemented in a discrete-time computer, computation and communication…
Breast cancer is the most frequently life-threatening diagnosed type of cancer among women. Early and accurate diagnosis by acquiring a tissue sample using biopsy techniques is essential. However, small lesions only visible by MRI are often missed in standard methods, indicating the need for a robot…
Targeting of small lesions with high precision is essential in an early phase of breast cancer for diagnosis and accurate follow up, and subsequently determines prognosis. Current techniques to diagnose breast cancer are suboptimal, and there is a need for a small, MRI-compatible robotic system able…
Modern robotic systems with a large number of actuated degrees of freedom can be utilized to perform several tasks at the same time while following a given order of priority. The most frequently used method is to apply null space projections to realize such a strict hierarchy, where lower priority t
This letter focuses on the problem of handling impacts by means of an aerial manipulator and proposes a solution that combines the control of the aerial manipulator's end-effector position with an innovative design approach of aerial manipulation systems, consisting of both active and passive joints
A manipulator with kinematic redundancy w.r.t. a main task enables to perform an additional, subordinate task in its null space. The classical hierarchy-based approach is to apply dynamically consistent null space projections such that this lower-priority task does not disturb the main task. The maj
Variable stiffness actuators (VSA) are fostered in robotics for their capability to address physical interaction with a physically adjustable compliance, being advantageous in terms of efficiency, safety and adaptability to unknown environments. Here we introduce the concept of a switching VSA (sVSA…
This paper proposes a semi-autonomous bilateral control architecture for unmanned aerial vehicles. During autonomous navigation, a human operator is allowed to assist the autonomous controller of the vehicle by actively changing its navigation parameters to assist it in critical situations, such as…
Quadrupedal running is an efficient form of locomotion found in nature, which serves as an inspiration for robotics. We believe that a resonance-based approach is the path towards energy-efficient legged locomotion and running robots. The first step in working towards this goal is creating an energy…