###### Abstract  
The contradiction between self-weight and load capacity of a power-assisted upper-limb exoskeleton for material hanging is unresolved. In this paper, a non-anthropomorphic 3-degree of freedom (DOF) upper-limb exoskeleton with an internally rotated elbow joint is proposed based on an anthropomorphic 5-DOF upper-limb exoskeleton for power-assisted activity. The proposed 3-DOF upper-limb exoskeleton contains a 2-DOF shoulder joint and a 1-DOF internally rotated elbow joint. The structural parameters of the 3-DOF upper-limb exoskeleton were determined, and the differences and singularities of the two exoskeletons were analyzed. The workspace, the joint torques and the power consumption of two exoskeletons were analyzed by kinematics and dynamics, and an exoskeleton prototype experiment was performed. The results showed that, compared with a typical anthropomorphic upper-limb exoskeleton, the non-anthropomorphic 3-DOF upper-limb exoskeleton had the same actual workspace; eliminated singularities within the workspace; improved the elbow joint force situation; and the maximum elbow joint torque, elbow external-flexion/internal-extension and shoulder flexion/extension power consumption were significantly reduced. The proposed non-anthropomorphic 3-DOF upper-limb exoskeleton can be applied to a power-assisted upper-limb exoskeleton in industrial settings. upper-limb exoskeleton; power-assisted; material hanging; workspace; non-anthropomorphic 3-DOF upper-limb exoskeleton; power-assisted; material hanging; workspace; non-anthropomorphic 3-DOF upper-limb exoskeleton; non-anthrop  
heavy. Hence, in industrial applications, it is necessary to ensure that it has a heavy load capacity and light self-weight, which is difficult for structural design. Professor [PERSON] of the University of Tsukuba in Japan developed a HAL-5 exoskeleton robot that weighted 21-kg [7; 8]. This robot can help rescuers, porters and other physically demanding staff and can also help disabled people and elderly people take care of themselves. [PERSON] and [PERSON] of Korea University of Technology and Education developed a 7-DOF upper-limb exoskeleton that can assist the human shoulder and elbow joints to complete daily activities [9]. [PERSON] and [PERSON] of the University of Washington designed an exoskeleton called CADEN-7 with seven active DOFs [10; 11; 12]. It can imitate the actions of 95% of healthy arms and is mainly used for rehabilitation, virtual reality simulation and power assistance. Professor [PERSON] of the Kanagawa Institute of Technology in Japan developed a wearable exoskeleton [13; 14]. It can increase a person's power by 0.5-1 times and provides help for nurses to help them move patients. [PERSON] and [PERSON] of the University of Saga in Japan developed a 6-DOF upper extremity exoskeleton called SUEFUL-6, which is used primarily to assist with the daily activities of the upper-limbs [15]. [PERSON] and [PERSON] in Spain designed the 5-DOF upper-limb exoskeleton IKO, which is mainly used to provide help in performing daily activities [16]. [PERSON] and [PERSON] of Huazhong University of Science and Technology in China developed a 10-DOF upper-limb exoskeleton prototype, which is mainly used to assist the body in daily activities. The shoulder joint contains 6-DOF, and the elbow and wrist joints each contain 4-DOF [17]. [PERSON] et al. of Hefei University of Technology designed a 6-DOF cable-driven upper limb exoskeleton (CABexo) based on epicyclic gear trains. This exoskeleton has a parallel mechanical structure to the traditional serial structure, but is stiffer and has a stronger carrying capacity. Comparisons between CABexo and some of the existing exoskeleton systems show that it is able to meet the movement needs of most disabled and elderly individuals [18]. These power-assisted exoskeletons with anthropomorphic structures fit well with the human arm in the course of work and can provide help to a user in daily life.