Exoskeleton for motion assistance has obtained more and more attention due to its advantages in rehabilitation and assistance for daily life. This research designed an estimation method of human joint torque by the kinetic human–machine interaction between the operator’s elbow joint torque and the output of exoskeleton. The human elbow joint torque estimation was obtained by back propagation (BP) neural network with physiological and physical input elements including shoulder posture, elbow joint-related muscles activation, elbow joint position, and angular velocity. An elbow-powered exoskeleton was developed to verify the validity of the human elbow joint torque estimation. The average correlation coefficients of estimated and measured three shoulder joint angles are 97.9%, 96.2%, and 98.1%, which show that estimated joint angles are consistent with the measured joint angle. The average root-mean-square error between estimated elbow joint torque and measured values is about 0.143[Formula: see text]N[Formula: see text]m. The experiment results proved that the proposed strategy had good performance in human joint torque estimation.

Objective The purpose of this study is to investigate the cortical activation during passive and active training modes under different speeds of upper extremity rehabilitation robots. Methods Twelve healthy subjects completed the active and passive training modes at various speeds (0.12, 0.18, and 0.24 m/s) for the right upper limb. The functional near-infrared spectroscopy (fNIRS) was used to measure the neural activities of the sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and prefrontal cortex (PFC). Results Both the active and passive training modes can activate SMC, PMC, SMA, and PFC. The activation level of active training is higher than that of passive training. At the speed of 0.12 m/s, there is no significant difference in the intensity of the two modes. However, at the speed of 0.24 m/s, there are significant differences between the two modes in activation levels of each region of interest (ROI) (P < 0.05) (SMC: F = 8.90, P = 0.003; PMC: F = 8.26, P = 0.005; SMA: F = 5.53, P = 0.023; PFC: F = 9.160, P = 0.003). Conclusion This study mainly studied on the neural mechanisms of active and passive training modes at different speeds based on the end-effector upper-limb rehabilitation robot. Slow, active training better facilitated the cortical activation associated with cognition and motor control. See Video Abstract, http://links.lww.com/WNR/A621.

Pressure ulcers, involving sub-dermal tissue damage and originating in deep tissue injury (DTI), have attracted much attention of physicians and researchers for three decades. Finite element (FE) model is a very efficient tool to investigate internal stresses and strains in human body that induce pressure ulcers. However, there was scarce report available to explore stresses distribution in human buttocks during manual wheelchair propulsion. A three-dimensional (3D) comprehensive FE model, incorporating ischial tuberosities (ITs), muscle, fat, and custom-contoured cushion (CCC), was developed to investigate internal stress distribution in soft tissue of the buttocks. Based on the FE model, pressure distribution under ITs in static sitting and during different wheelchair propulsions is studied. Internal stresses in fat and muscle were about three times and five times higher than that on cushion surface in terms of static sitting and wheelchair propulsion. All peak pressures under wheelchair propulsion were higher than those of static sitting, and peak pressures went on increasing with increase of wheelchair movement speed. This method based on the comprehensive FE model allowed for the optimization of wheelchair seat cushion design.

To help hemiplegic patients with stroke to restore impaired or lost upper extremity functionalities efficiently, the design of upper limb rehabilitation robotics which can substitute human practice becomes more important. The aim of this work is to propose a powered exoskeleton for upper limb rehabilitation based on a wheelchair in order to increase the frequency of training and reduce the preparing time per training. This paper firstly analyzes the range of motion (ROM) of the flexion/extension, adduction/abduction, and internal/external of the shoulder joint, the flexion/extension of the elbow joint, the pronation/supination of the forearm, the flexion/extension and ulnar/radial of the wrist joint by measuring the normal people who are sitting on a wheelchair. Then, a six-degree-of-freedom exoskeleton based on a wheelchair is designed according to the defined range of motion. The kinematics model and workspace are analyzed to understand the position of the exoskeleton. In the end, the test of ROM of each joint has been done. The maximum error of measured and desired shoulder flexion and extension joint angle is 14.98%. The maximum error of measured and desired elbow flexion and extension joint angle is 14.56%. It is acceptable for rehabilitation training. Meanwhile, the movement of drinking water can be realized in accordance with the range of motion. It demonstrates that the proposed upper limb exoskeleton can also assist people with upper limb disorder to deal with activities of daily living. The feasibility of the proposed powered exoskeleton for upper limb rehabilitation training and function compensating based on a wheelchair is proved.

The incidence of lower limb amputation has increased in recent years. Prosthesis is the most important assistive device to compensate for limb defects in amputation patients and restore their abilities. The prosthetic socket is a key component connecting the residual limb and the prosthesis, with a direct effect on the function of the prosthesis and the patient’s comfort. As prosthetic socket design relies on the personal experience of prosthetists, this study explored an optimized prosthetic socket design method that combined the experiences of multiple prosthetists. The eigenvector algorithm was adopted to optimize the factors influencing prosthetic socket design and their quantitative compensations based on the design experience of prosthetists. Clinical assessments indicated that the proposed socket design method substantially improved fitting effects. This quantitative compensation design for prosthetic sockets will help overcome the limitations of traditional prosthetic socket design, which will be of great importance in improving the design accuracy and efficiency of prosthetic sockets.