We propose a new telerobotic system for untact swab sampling to prevent the infection of medical staff during upper respiratory sample collection. The system consists of a slave robot and two master devices. The slave robot is designed to move a swab in 6 degrees of freedom within the facial area and to insert and remove the swab under remote control by an operator at the master site based on magnified imaging of the patient’s facial area. The insertion and removal of the swab into and from the nostril are implemented by means of a swab insertion unit; as the counterpart to this unit, the master system also includes a swab insertion device to control the swab insertion unit remotely. A force sensor installed on the swab holder enables monitoring of the force generated when the swab touches the target. In experiments, a virtual specimen was installed on the posterior nasopharynx wall of a life-size head phantom model. The nasopharyngeal swab samplings of the phantom model were successfully performed thanks to the force monitoring capability of the proposed telerobotic system, showing that this system is suitable for remote upper respiratory sample collection.
A body pressure relief system was newly developed with optical pressure sensors for pressure ulcer prevention. Unlike a conventional alternating pressure air mattress (APAM), this system automatically regulates air flow into a body supporting mattress with adaptive inflation (or deflation) duration in response to the pressure level in order to reduce skin stress due to prolonged high pressures. The system continuously quantifies the body pressure distribution using time-of-flight (ToF) optical sensors. The proposed pressure sensor, a ToF optical sensor in the air-filled cell, measures changes in surface height of mattress when pressed under body weight, thereby indirectly indicating the interface pressure. Non-contact measurement of optical sensor usually improves the durability and repeatability of the system. The pressure sensor was successfully identified the 4 different-predefined postures, and quantitatively measured the body pressure distribution of them. Duty cycle of switches in solenoid valves was adjusted to 0–50% for pressure relief, which shows that the interface pressure was lower than 32 mmHg for pressure ulcer prevention.
Intracranial dural arteriovenous fistula (DAVF) is rare and potentially life-threatening disease often presenting as vascular myelopathy. The early and proper diagnosis is challenging because the clinical manifestations are related to the distribution of the draining vein, not the fistula site, and imaging findings are similar to demyelinating disease of the spinal cord. The authors present the case of a 45-year-old man who developed acute progressive quadriplegia and respiratory difficulty with an enhancing, longitudinally extensive cervical cord lesion. These symptoms were highly suspicious for transverse myelitis but were caused by an intracranial DAVF. Intracranial DAVF with venous reflux to the brainstem and spinal cord is a rare but important differential diagnosis of progressive worsening myelopathy that is treatment resistant and gives the diagnostic impression of transverse myelitis.
4 March 2022 in Journal of Mechanisms and Robotics
This paper presents a new forward kinematic approach for the 3–6 Stewart platform. In the 3–6 Stewart platform, the position and orientation of the moving platform can be determined through kinematic constraint equations that indicate the possible trajectories of the three joints on the platform from the base coordinates. In most previous studies, the constraint equations were obtained through vector equations, which involve many complicated steps and multiple variables. Based on Denavit–Hartenberg (D-H) notation, the proposed approach allows a constraint equation representation with only four parameters. In addition, to implement the forward kinematics with the fewest possible D-H parameters, the 3–6 Stewart platform is reconfigured into three virtual revolute joints sharing base coordinates. Consequently, the constraint equations can be intuitively derived, and the computation process becomes more concise. The feasibility of the proposed approach is verified through an iterative numerical analysis and a simulation comparison with the general inverse kinematics.