In this work we present a novel method to estimate online the torques at the knee joints with the goal to generate reference signals for knee assistive devices. One of the main advantages of the proposed approach is its reduced sensing requirements, which leads to an ergonomic setup with minimal instrumentation, especially above the knee and of the upper body. Indeed, only the measurement of the forces and torques exchanged between the ground and the user's feet, the posture of the shanks, and the model of the user's shank itself are needed for the estimation of the knee torque. The method does not require information of the state of the upper body and of a possible payload i.e. body pose, mass and center of mass (CoM) location. As a result, a minimalistic sensory system consisting of sensorized shoes and IMUs to track the shanks' orientation are adequate, allowing for an easily wearable and portable setup. The estimation of the knee torques is achieved by imposing an equilibrium condition to the user's shank. Several experiments were performed to test the effectiveness of the proposed estimation method under different body postures and motions (e.g. squat motion and switching foot contacts) and payloads (e.g. by holding weights at different arm postures resulting in variable upper body CoM). Finally an assistive task, conducted with the iT-Knee bipedal system is presented, where the lifted payload changed its CoM location over time.
Occupational Safety and Health (OSH) is defined through three objectives: (i) maintenance of workers' health; (ii) improvement of working environment and safety; and (iii) promotion of a work culture that supports health and safety. In industry, the most frequent threat to workers' health is musculoskeletal disorders. Furthermore, even routine tasks in certain work environments (nuclear, construction, disaster response, marine, chemical, etc.) expose workers to extreme risks like explosions, contaminations, fires, confined spaces, debris, toxic gases, etc. The goal of this research is to design and develop advanced collaborative robotic technologies towards: (i) reducing workers' physical stress and improving their health through a novel modular full-body wearable exoskeleton with arm, lower-back, and leg modules, allowing full motion dexterity; and (ii) avoiding hazard-prone worker environments and improving safety through a new collaborative master-slave teleoperation system consisting of: (a) a hydraulicallydriven, quadruped field robot with a robotic manipulator arm for operation in hazardous environments; (b) a hand exoskeleton master device for teleoperation control. The article presents the current status of development of these technologies. Preliminary validation of the exoskeleton shows reductions in muscular efforts of up to 30% for the lower back. For the master-slave collaborative system, (a) the Hydraulic Quadruped robot prototypes can traverse rough environments through capabilities that include stair climbing, walking over obstacles, omni-directional trotting with step reflexes, running, jumping, and self-righting; (b) the 7 degrees-of-freedom (DOF) manipulator arm allows object manipulation in a large workspace with dexterous grasping of up to 160 N of payload; and (c) the novel HEXOTRAC 3-digit hand exoskeleton provides high-resolution tracking of fingers and provides force feedback for intuitive bilateral teleoperation of robotic manipulators. These next-generation industrial exoskeletons and collaborative teleoperation systems can address the emerging challenges in industrial workers' health and safety.
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