Qingyun Meng

Ankle rehabilitation robots represent an important branch of rehabilitation robotics, offering significant potential to improve the quality of life for patients with ankle dysfunction caused by stroke, sports injuries, and other conditions. This review first outlines the anatomy and range of motion of the ankle joint, compares conventional rehabilitation approaches with robot-assisted therapy, and highlights the clinical significance of ankle rehabilitation robots. It then systematically examines current research progress from two core perspectives: mechanical structure design and control strategies. In mechanical design, the performance characteristics of series versus parallel mechanisms are compared, the advantages and limitations of actuation methods such as electric motors and pneumatic artificial muscles are analyzed, and the application contexts of platform-based and wearable robots are discussed. In control strategies, the discussion covers motion control and human–robot interaction, beginning with fundamental position, velocity, and trajectory tracking control, and extending to intention-level and cognitive interaction. Finally, based on current research and clinical needs, future ankle rehabilitation robots are expected to evolve toward greater flexibility, intelligence, and universality, providing a theoretical foundation for future studies.

With the development of medical-engineering integration technology and the growing clinical rehabilitation demands, intelligent rehabilitation robots have emerged as a prominent area of research in stroke rehabilitation. The application of exoskeleton rehabilitation robots holds significant potential to alleviate the pressure on rehabilitation resources in China. These robots offer high-intensity, high-repetition rehabilitation training for stroke patients, helping to restore limb motor function, improve daily living independence, and contribute to neuroplasticity. As such, they are becoming an essential treatment modality for patients with motor function disorders. In this review, we first categorize ankle-foot rehabilitation robots based on the interaction methods between the robot and the user, detailing their structural characteristics and application scenarios. Additionally, we classify existing control strategies, including admittance control, impedance control, electromyography control, trajectory tracking control, and Proportional-Integral-Derivative control, based on the rehabilitation needs at various stages of recovery. Each control method is summarized, and their current research status is analyzed. Besides, current research status of key technologies in rehabilitation robots, both domestically and internationally are also summarized in this paper. Finally, the key challenges in the development of ankle-foot rehabilitation robots and future research directions are discussed, providing a reference for the research and design of these robots.

The Visual-inertial navigation system (VINS) integrates visual and inertial sensors, providing advanced navigation capabilities. Recent improvements in these sensors have made VINS widely applicable in areas such as robotic navigation and autonomous driving, due to its complementary functionality and decreasing sensor costs. This paper reviews the latest developments in VINS, introducing visual simultaneous localization and mapping and its role in VINS. Key technologies, including direct and indirect methods for image processing in visual odometry and Inertial Measurement Unit preintegration for robot motion estimation, are discussed. Both filter-based and optimization-based state estimation methods in VINS are examined. Filter-based methods, like the Extended Kalman Filter, offer real-time state updates for attitude tracking and map construction, while optimization-based methods focus on minimizing reprojection or other error metrics to improve localization accuracy and robustness. The application of dynamic simultaneous localization and mapping, which addresses dynamic objects in complex environments, is also explored. This paper summarizes current research challenges and proposes future directions in the field of dynamic simultaneous localization and mapping.

This paper presents the mechanical design and test of a portable hand-elbow combination linkage upper limb rehabilitation robot, which can realize the joint movement of the hand joint and elbow joint and reproduce the complete grasping action. The joints that need bionic support are determined according to the characteristics of human upper limbs and hands, and the overall bionic mechanism is designed. The Motion module in SolidWorks is used to simulate and analyze the rehabilitation robot. The measurement experiment and grasping experiment of joint mobility are carried out on the experimental prototype. As a result, the angular displacement and linear displacement curves obtained via the simulation results are smooth. The measurement experiment of the joint range of motion confirms that the joint range of motion is also within the range of the normal joint angle of the human body, and the grasping experiment shows that the exoskeleton can grasp and lift a 1.801-kg cylindrical object and other daily necessities of different shapes. This result shows that the design of the portable hand-elbow combination linkage upper limb rehabilitation robot is reasonable, can satisfy the rehabilitation training requirements of the hand and upper limb, and has some ability to assist users in daily life.

Existing ankle rehabilitation robots are large, difficult to move, and mostly designed for seated use, which cannot meet the early bedridden rehabilitation goals of stroke patients. To address these issues, a supine ankle rehabilitation robot (S-ARR) specifically designed for early bedridden rehabilitation of stroke patients has been proposed. The S-ARR is designed to be easily movable and adaptable to different heights. It features a variable workspace with mechanical limiters at the rotating joints. A kinematic model has been constructed, and the kinematic simulation of the S-ARR has been analyzed. A control system scheme for the S-ARR has been proposed. Additionally, experiments have been conducted on the prototype to measure joint range of motion and perform rehabilitation exercises. The simulation and experimental results demonstrate that the S-ARR has a feasible workspace and a relatively smooth motion process, enabling it to achieve supine ankle rehabilitation training. This indicates that the design of the supine ankle rehabilitation robot is reasonable, capable of meeting the requirements for ankle joint rehabilitation training, and has practical utility.

This paper presents the modeling design method for a novel hybrid-driven compliant hand exoskeleton based on the human-machine coupling model for the patients who have requirements on training and assisting. Firstly, the human-machine coupling model is established based on the kinematics characteristics of human fingers and the Bernoulli beam formula. On this basis, the variable stiffness flexible hinge (VSFH) is used to drive the finger extension and the cable-driven mechanism is used to implement the movement of the finger flexion. Here, a hand orthosis is designed in the proposed hand exoskeleton to act as the base and maintain the function position of the hand for patients with hand dysfunction. Then, a final design prototype is fabricated to evaluate the proposed modeling method. In the end, a series of experiments based on the prototype is proceeded to evaluate its capabilities on stretching force for extension, bio-imitability, finger flexion capability, and fingertip force. The results show that the prototype has a significant improvement in all aspects of the ability mentioned above, and has good bionics. The proposed design method can be utilized to implement the rapid design of the hybrid-driven compliant hand exoskeleton with the changed requirements. The novel modeling method can be easily applied in personalized design in rehabilitation engineering.