Design and Analysis of a Rigid‐Flexible Parallel Mechanism for a Neck Brace

Abstract

A rigid-flexible parallel mechanism called 3-RXS mechanism as a neck brace for patients with head drooping symptoms (HDS) is presented. The 3-RXS neck brace has a simple and light structure coupled with good rotation performance, so it can be used to assist the neck to achieve flexion and extension, lateral bend, and axial torsion. Firstly, to prove that the X-shaped compliant joint has a rotational degree of freedom (DoF) and can be used in the 3-RRS spherical parallel mechanism (3-RRS SPM), the six-dimensional compliance matrix, axis drift, and DoF of the X-shaped compliant joint have been systematically calculated. Secondly, the 3-RXS mechanism and its pseudo-rigid-body model (PRBM) are obtained by replacing the revolute pair with the X-shaped compliant joint in the 3-RRS SPM. The rotation workspace of the 3-RXS mechanism is also performed. Finally, to verify the rotation function and effect of 3-RXS mechanism for neck-assisted rehabilitation, the kinematics simulations of the 3-RXS and 3-RRS mechanisms are carried out and compared with the theoretical result, and a primary experiment for rotation measurement of 3-RXS mechanism prototype is carried out. All results prove the feasibility of the 3-RXS mechanism for a neck brace.

Conceptual design and virtual prototyping of a wearable upper limb exoskeleton for assisted operations

“…Their primary function is to assist people during the execution of specific movements by providing supplementary strength, making it possible, for instance, to deal with greater loads, to compensate for a lack of muscularity and to prevent from excessive fatigue. Wearable assistive devices, usually referred to as exoskeletons, are commonly designed to operate along their human counterparts, namely the lower/upper limbs or the neck area, though in the last case, if no particular functionalities are provided, the device could be better identified as a brace [24]. Ready examples of commercially available exoskeletons are the Mate, [19], the AirFrame [20] and the ShoulderX [21] for the upper limbs, the LegX [22] and the Hercule [25] for the lower limbs, and the Laevo V2 Fig.…”

Preliminary Study on Effects of Neck Exoskeleton Structural Design in Patients With Amyotrophic Lateral Sclerosis

“…Neck exoskeletons represent a viable alternative solution to not only support but also actively enable head-neck motions in ALS patients. To date, most neck exoskeletons use parallel mechanisms in their design to support the weight of the head and accommodate the large range, spatial rotations of the head [12], [13], [24]- [28]. This is because all actuators can…”

A Review of Parallel Robots: Rehabilitation, Assistance, and Humanoid Applications for Neck, Shoulder, Wrist, Hip, and Ankle Joints

“…The mechanism consisted of a series of links connected to both the top and fixed platforms through a sequence of joints in the following order: revolute joint (R), X-shaped compliant joint (X), and spherical joint (S). This construction was simple and lightweight, enabling smooth flexion/extension, left/right lateral bending, and axial rotational movements [38].…”

“…In the rehabilitation sphere, there are models such as 3-RPS [1] and 3-RRR [2]. In the context of assistance robots, configurations like 3-RRS [36], 3-RRR [37], and 3-RXS [38] are used. Humanoid robotics often favor cable-driven mechanisms [3,39,[41][42][43].…”

“…The performance evaluation of parallel robots is multi-faceted, typically incorporating metrics such as speed [28,59], accuracy [33,53,57,84,104,108], repeatability, loadcarrying capacity [79,80], energy efficiency, and safety [96]. Methods for performance evaluation include computational methods, and simulations for statistical analysis and finite element analysis (FEA) for mechanical property evaluation are popular choices [38]. Furthermore, various software tools were prevalent for simulation and analysis in the studies reviewed.…”