## 1 Introduction  
Patients who have had a cerebrovascular accident (stroke) commonly have a degree of hand impairments, which can manifest as muscle weakness, joint stiffness, or a deficit in motor planning and motor learning [1]. According to an Australian government guide [2], a complete loss of hand results in a 54% whole-person impairment (WPI), and a loss of one finger results in at least a 5% WPI. Rehabilitation for the entire hand and for each finger digit following a stroke is critical for motor control recovery and an enhanced quality of life. Robotic gloves that assist the hand in performing repetitive rehabilitation movements have been testified to be effective in promoting the rehabilitation process [3; 4; 5]. Soft robotic gloves driven by pneumatic actuators made of silicon rubber have attracted the interest of researchers in recent years due to their higher compliance to the wearer and environment compared to motor-driven rigid robotic gloves [6; 7; 8; 9]. Soft pneumatic actuators of soft robotic gloves can be categorized into two types in terms of construction: whole-finger type and modular/segmented type. The whole-finger type has pneumatic chambers or pockets that run from the tip to the root, covering all the finger joints and segments. When the chambers are pressurized, all the joints flex at the same time. For example, [PERSON] et al. (2010) and [PERSON] et al. (2011, 2012) developed fiber-reinforced actuators with a single-chamber main body that extends from the fingertip to the middle of the metacarpal bones. The reinforcement fibers are coiled outside the body in various patterns, causing the actuator to bend, twist, and stretch upon air inflation. Other classical soft actuators, the Pneu-net actuators designed by [PERSON] (2013); [PERSON] et al. (2014), and [PERSON] et al. (2015), consist of a strain-limited bottom layer and an elastomer body embedded with multiple chambers connected in series. The angle of these chambers is carefully adjusted to achieve the actuator's bending, twisting, and coupled deformations. These Pneu-net and fiber-reinforced soft actuators can impel a finger to perform flexion motions. However, they lack ergonomics and may impose a burden on the finger since they are deformed into a curve that deviates from the finger outline, resulting in a high binding force at the phalanges (forces restrict the actuator to bulge) ([PERSON] et al., 2016). The Modular/segmented type, however, has chambers only above the finger joints, aiming to provide bending force at finger joints instead of the phalanges. [PERSON] et al. (2016); [PERSON] et al. (2017), and [PERSON] et al. (2018) shortened the air chamber of the Pneu-net actuator in (2013, 2014) and connected chambers with solid silicon or inflexible components. Similarly, the fiber-reinforced actuators designed by [PERSON] et al. (2019) and [PERSON] et al. (2020, 2012) have chamber segments on the distal interphalangeal joint, proximal interphalangeal joint, and metacarpophalangeal (MCP) joint, respectively. The bellow-shaped actuator, another type of soft actuator popular in the past five years, is usually utilized in a modular fashion in a robotic glove. The even change of the bellow's peripheric zigzag angle results in longitudinal extension, whereas the uneven peripheral change results in radius bending. For example, [PERSON] et al. (2018) and [PERSON] et al. (2018) developed robotic gloves with three bellow modules on each of the four-finger digits and two modules on the thumb for finger flexion and extension. These actuator modules or segments can connect to separate air inlets, allowing them to control the independent bending of each joint. In general, the above-mentioned whole-finger and modular actuators can provide adequate support for achieving a full range of motion (RoM) of finger flexion (1.2-3.6 N flexion force). Nevertheless, they are insufficient in thumb abduction and opposition support, and the two types of actuators have deficits in different aspects of thumb motion support.