*Review* **Measurement, Evaluation, and Control of Active Intelligent Gait Training Systems—Analysis of the Current State of the Art**

**Yi Han 1,2,†, Chenhao Liu 1,† , Bin Zhang <sup>1</sup> , Ning Zhang <sup>3</sup> , Shuoyu Wang <sup>2</sup> , Meimei Han <sup>4</sup> , João P. Ferreira <sup>5</sup> , Tao Liu <sup>1</sup> and Xiufeng Zhang 3,\***


**Abstract:** Gait recognition and rehabilitation has been a research hotspot in recent years due to its importance to medical care and elderly care. Active intelligent rehabilitation and assistance systems for lower limbs integrates mechanical design, sensing technology, intelligent control, and robotics technology, and is one of the effective ways to resolve the above problems. In this review, crucial technologies and typical prototypes of active intelligent rehabilitation and assistance systems for gait training are introduced. The limitations, challenges, and future directions in terms of gait measurement and intention recognition, gait rehabilitation evaluation, and gait training control strategies are discussed. To address the core problems of the sensing, evaluation and control technology of the active intelligent gait training systems, the possible future research directions are proposed. Firstly, different sensing methods need to be proposed for the decoding of human movement intention. Secondly, the human walking ability evaluation models will be developed by integrating the clinical knowledge and lower limb movement data. Lastly, the personalized gait training strategy for collaborative control of human–machine systems needs to be implemented in the clinical applications.

**Keywords:** rehabilitation and assistance system; lower limbs; intention recognition; gait training; gait evaluation; human–machine interaction control strategy
