research on adjusting limb kinematics according to the peripheral neuromechanics of the hip joint needs to be further explored and developed. [PERSON] et al. [14] designed a kinematically compatible 4-DOF robotic hip exoskeleton for gait rehabilitation, and verified the effect of this exoskeleton robot in assisting patients with rehabilitation training through the evaluation of dynamic assistance. [PERSON] et al. [15] designed an asymmetric fully constrained mechanism with three rotational degrees of freedom and three drives, and proposed the non-singular residue method based on reciprocity to eliminate singularities, thus preventing singularities. Along with the human hip joint, [PERSON] et al. [16] proposed a deformed mechanism with 3-UPS/S and 2-RPS/UPS/S configurations suitable for lower limb rehabilitation. The two configurations can be converted into each other, and the rotation center of the motion platform is designed to pass through the human hip joint to meet the needs of patients in different rehabilitation stages.  
Because soft robots [17; 18] are made of flexible materials, such as silicon, textiles, flexible plastics or cables, and because they are cheaper to manufacture, [PERSON] et al. [19] presented a hip flexion rehabilitation exoskeleton driven by a soft pneumatic actuator manufactured with flexible materials, and the target torque of hip flexion was evaluated, which verified the effectiveness of pneumatic muscles in providing hip flexion assistance. Because the structure and materials of soft robots are nonlinear and have multiple degrees of freedom, their action tasks are more complex than those of rigid robots, which require very high algorithm requirements [16; 20; 21] and need to be continuously developed. However, the selection of materials can provide a reference in the process of building experimental prototypes in subsequent mechanisms, and the rigid-flexible coupling [22; 23; 24] effect can make the rehabilitation training of patients more comfortable. [PERSON] et al. [25] proposed a lightweight active wearable power device with a carbon-fiber structure. Two elastic actuators were used to assist the flexion and extension of the hip joint. The dynamic characteristics of the actuator were experimentally characterized, and the effectiveness of the device in typical gait assistance scenarios was evaluated. This provides a reference direction for the development of rehabilitation robots. Designers of future rehabilitation devices should lay more emphasis on portability, intelligent control and modular structure design [26; 27].  
In view of the design of various hip joint rehabilitation devices, this paper proposes a new spatial 8R hip joint rehabilitation mechanism with a compact and stable structure, large stiffness, strong bearing capacity and simple control that fits closely on the hip joint and assists the thigh in forward flexion, backward extension, abduction and adduction movements. The rest of the paper is organized as follows. In Section 2, we introduce the configuration design of the spatial 8R mechanism. Then, in Section 3, we present the kinematic model of the spatial 8R mechanism and conduct kinematic performance analysis. Section 4 analyzes the variations in different movements in one cycle of this hip rehabilitation mechanism. Finally, conclusions are drawn in Section 5.