## 1 Introduction
[PERSON] (Laboratory of Robotic Mechatronics, Department of Industrial Engineering, University of Tovergata) describes a finger exoskeleton with a prototype of the ExoFinger, the experiments describe the proper operation of the ExoFinger. In addition, the skeleton has various functions for motion control and medical monitoring sensors [17]. Nuevo Leon developed a wearable finger exoskeleton, motion transmission is based on a linkage mechanism that allows the possibility of coupled phalanx movements, thus using only one active degree of freedom, one linear for each finger drive, meaning that you can achieve the natural movement of the hand [18]. [PERSON] (Faculty of Information, University of Debrecen) designed and developed a novel cost-effective mechatronic system for continuous passive motion training of fingers and wrists [19]. [PERSON] (Department of Mechanical Engineering, Indian Institute of Technology) proposed a stroke rehabilitation hand exoskeleton with flexible structure and control, and verified its potential clinical effectiveness through preliminary clinical trials in stroke patients [20]. [PERSON] et al. (Department of Mechanical Engineering, Asia University) developed a dexterous anthropomorphic robotic hand with integrated linkage actuation. The mechanism is constructed through a fusion of parallel and series mechanisms to achieve two-DOF motion in the metacarpophalangeal joint and single-DOF motion in the proximal interphalangeal joint through a link combination [21]. [PERSON] (Department of Mechanical Engineering at Virginia Tech) designed a robotic exoskeleton glove for stable grip control [22]. [PERSON] (University of Pontificia) has solved the problem of how to provide active support through a robot-assisted exoskeleton, by developing a new closed-loop structure that continuously measures electromyographic signals (EMG) to adjust the assistance provided by the exoskeleton [23]. [PERSON] (Southern Taiwan University of Science and Technology) designed an exoskeleton assistive device to help hemiplegic stroke patients stretch their fingers and open their palms to simulate the effect of rehabilitation [24]. [PERSON] (Department of Mechanical Engineering) developed a portable and spring-guided hand exoskeleton system for exercising finger flexion and extension [25]. [PERSON] from the State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, designed an active and passive control system for the exoskeleton rehabilitation hand, which can adapt to fingers of different thicknesses and lengths to prevent secondary injuries [26]. [PERSON] (School of Mechanical Engineering, Xi'an Jiaotong University) designed an attention-controlled finger extension and flexion rehabilitation hand based on a rigid-flexible combined mechanism. Due to the design and characteristics of its new multi-segment mechanism driven by steel springs, it can help the fingers to stretch and curve [27]. [PERSON] (Institute of Automation, Chinese Academy of Sciences) proposed a novel controller for finger position detection and tracking control of a wearable hand rehabilitation robot [28]. [PERSON] (Laboratory of Rehabilitation Engineering, School of Control Science and Engineering, Shandong University) designed a wearable robotic hand exoskeleton based on surface EMG signals, which has greater freedom of movement, greater range of joint motion, and can be freely controlled according to motion intentions [29]. [PERSON] (Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston) developed an intent-driven hand training system using sEMG as intention recognition device [30]. The hand functional rehabilitation training devices and exoskeleton devices developed by different research institutions have different structures and driving modes. The main structure of a hand rehabilitation robot includes linkage mechanism, micro cylinder mechanism, cable drive mechanism, gear mechanism, flexible mechanism, and so on.