Human-Mechanical system interaction in Virtual Reality

The present work aims to show the great potential of Virtual Reality (VR) technologies in the field of Human-Robot Interaction (HRI). Indeed, it is foreseeable that in not too distant future cooperating robots will be increasingly present in human environments. Many authors actually believe that after the current information revolution, we will witness the so-called "robotics revolution", with the spread of increasingly intelligent and autonomous robots capable of moving into our own environments. Since these machines must be able to interact with human beings in a safe way, new design tools for the study of Human-Robot Interaction (HRI) are needed. The author believes that VR is an ideal design tool for the study of the interaction between humans and automatic machines, since it allows the designers to interact in real-time with virtual robotic systems and to evaluate different control algorithms, without the need of physical prototypes. This also shields the user from any risk related to the physical experimentation. However, VR technologies have also a more immediate application in the field of HRI, such as the study of usability of interfaces for real-time controlled robots. In fact, these robots, such as robots for microsurgery or even "teleoperated" robots working in a hostile environments, are already quite common. VR allows the designers to evaluate the usability of such interfaces by relating their physical input with a virtual output. In particular, the author has developed a new software application aimed at simulating automatic robots and, more generally, mechanical systems in a virtual environment. The user can interact with one or more virtual manipulators and also control them in real-time by means of several input devices. Finally, an innovative approach to the modeling and control of a humanoid robot with high degree of redundancy is discussed. VR implementation of a virtual humanoid is useful for the study of both humanoid robots and human beings

Kinematics and Robot Design II (KaRD2019) and III (KaRD2020)

This volume collects papers published in two Special Issues “Kinematics and Robot Design II, KaRD2019” (https://www.mdpi.com/journal/robotics/special_issues/KRD2019) and “Kinematics and Robot Design III, KaRD2020” (https://www.mdpi.com/journal/robotics/special_issues/KaRD2020), which are the second and third issues of the KaRD Special Issue series hosted by the open access journal robotics.The KaRD series is an open environment where researchers present their works and discuss all topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. It aims at being an established reference for researchers in the field as other serial international conferences/publications are. Even though the KaRD series publishes one Special Issue per year, all the received papers are peer-reviewed as soon as they are submitted and, if accepted, they are immediately published in MDPI Robotics. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”.KaRD2019 together with KaRD2020 received 22 papers and, after the peer-review process, accepted only 17 papers. The accepted papers cover problems related to theoretical/computational kinematics, to biomedical engineering and to other design/applicative aspects

Design, implementation, control, and user evaluations of assiston-arm self-aligning upper-extremity exoskeleton

Physical rehabilitation therapy is indispensable for treating neurological disabilities. The use of robotic devices for rehabilitation holds high promise, since these devices can bear the physical burden of rehabilitation exercises during intense therapy sessions, while therapists are employed as decision makers. Robot-assisted rehabilitation devices are advantageous as they can be applied to patients with all levels of impairment, allow for easy tuning of the duration and intensity of therapies and enable customized, interactive treatment protocols. Moreover, since robotic devices are particularly good at repetitive tasks, rehabilitation robots can decrease the physical burden on therapists and enable a single therapist to supervise multiple patients simultaneously; hence, help to lower cost of therapies. While the intensity and quality of manually delivered therapies depend on the skill and fatigue level of therapists, high-intensity robotic therapies can always be delivered with high accuracy. Thanks to their integrated sensors, robotic devices can gather measurements throughout therapies, enable quantitative tracking of patient progress and development of evidence-based personalized rehabilitation programs. In this dissertation, we present the design, control, characterization and user evaluations of AssistOn-Arm, a powered, self-aligning exoskeleton for robotassisted upper-extremity rehabilitation. AssistOn-Arm is designed as a passive back-driveable impedance-type robot such that patients/therapists can move the device transparently, without much interference of the device dynamics on natural movements. Thanks to its novel kinematics and mechanically transparent design, AssistOn-Arm can passively self-align its joint axes to provide an ideal match between human joint axes and the exoskeleton axes, guaranteeing ergonomic movements and comfort throughout physical therapies. The self-aligning property of AssistOn-Arm not only increases the usable range of motion for robot-assisted upper-extremity exercises to cover almost the whole human arm workspace, but also enables the delivery of glenohumeral mobilization (scapular elevation/depression and protraction/retraction) and scapular stabilization exercises, extending the type of therapies that can be administered using upper-extremity exoskeletons. Furthermore, the self-alignment property of AssistOn-Arm signi cantly shortens the setup time required to attach a patient to the exoskeleton. As an impedance-type device with high passive back-driveability, AssistOn- Arm can be force controlled without the need of force sensors; hence, high delity interaction control performance can be achieved with open-loop impedance control. This control architecture not only simpli es implementation, but also enhances safety (coupled stability robustness), since open-loop force control does not su er from the fundamental bandwidth and stability limitations of force-feedback. Experimental characterizations and user studies with healthy volunteers con- rm the transparency, range of motion, and control performance of AssistOn- Ar

Haptic Guidance for Extended Range Telepresence

A novel navigation assistance for extended range telepresence is presented. The haptic information from the target environment is augmented with guidance commands to assist the user in reaching desired goals in the arbitrarily large target environment from the spatially restricted user environment. Furthermore, a semi-mobile haptic interface was developed, one whose lightweight design and setup configuration atop the user provide for an absolutely safe operation and high force display quality

Novel tele-operation of mobile-manipulator systems

A novel algorithm for the simplified tele-operation of mobile-manipulator systems is presented. The algorithm allows for unified, intuitive, and coordinated control of mobile manipulators, systems comprised of a robotic arm mounted on a mobile base. Unlike other approaches, the mobile-manipulator system is modeled and controlled as two separate entities rather than as a whole. The algorithm consists of thee states. In the rst state a 6-DOF (degree-of-freedom) joystick is used to freely control the manipulator's position and orientation. The second state occurs when the manipulator approaches a singular configuration, a con guration where the arm instantaneously loses a DOF of motion capability. This state causes the mobile base to proceed in such a way as to keep the end-effector moving in its last direction of motion. This is done through the use of a constrained optimization routine. The third state is triggered by the user: once the end-effector is in the desired position, the mobile base and manipulator both move with respect to one another keeping the end-effector stationary and placing the manipulator into an ideal configuration. The proposed algorithm avoids the problems of algorithmic singularities and simplifies the control approach. The algorithm has been implemented on the Jasper Mobile-Manipulator System. Test results show that the developed algorithm is effective at moving the system in an intuitive manner

GRASP News Volume 9, Number 1

A report of the General Robotics and Active Sensory Perception (GRASP) Laboratory