## 5 Discussion  
In this study, we developed a unilateral knee-actuated exoskeletal gait orthosis (KAEGO) for gait training in patients with hemiplegia. The KAEGO system facilitates rehabilitation progress through interaction between the orthosis and the patient in over-ground environments, operating in accordance with the gait intentions of the hemiplegic patient. To achieve this, this study proposes a simple gait control strategy using an IMU sensor and a knee angle sensor. This approach detects gait phases and recognizes the patient's gait intentions, eliminating the need for GRF sensors. Additionally, we implemented a simple torque generation method based on a negative damping model to assist knee joint movements. Two types of walk tests were conducted to evaluate the effectiveness of the proposed control strategy, focusing on the accuracy of gait recognition and the comfort of gait assistance. The first experiment involved a hemiplegic patient and a healthy individual performing 10 m walk tests. Data collected during these tests were used to analyze gait recognition accuracy and how quickly the gait intention were identified. In the second experiment, we hypothesized that the KAEGO, by providing appropriate assistive torque, would reduce \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Trial** & **COT** & **Velocity (m/s)** & **VO2** (mL/min/kg)** & **HR** (ppm)** & **Distance** **Traveled (m)** \\ \hline without KAEGO & \(11.5\) & \(0.39\) & \(12.0\) & \(129.4\) & \(153.2\) \\ with KAEGO & \(10.5\) & \(0.44\) & \(12.3\) & \(132.4\) & \(154.1\) \\ \hline \% of difference & \(-8.70\) & \(12.82\) & \(2.50\) & \(2.32\) & \(0.59\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The first trial of the 6 min walking test and the results of the metabolic cost of transport (COT). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Trial** & **COT** & **Velocity (m/s)** & **VO2** (mL/min/kg)** & **HR** (ppm)** & **Distance** **Traveled (m)** \\ \hline without KAEGO & \(8.8\) & \(0.42\) & \(10.9\) & \(128.0\) & \(154.5\) \\ with KAEGO & \(8.1\) & \(0.46\) & \(9.8\) & \(127.2\) & \(167.5\) \\ \hline \% of difference & \(-7.95\) & \(9.52\) & \(-10.09\) & \(-0.62\) & \(8.41\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The second trial of the 6 min walking test and the results of the metabolic cost of transport (COT). the metabolic cost despite potential discomfort from the device's weight (3.4 kg) and wearability issues. To test this hypothesis, we measured the metabolic cost of transport (COT) during a six-minute walk test. Results from the 10 m WT showed that the gait intentions were accurately recognized without errors, and transitions could be rapidly detected approximately 100 ms before the start of the swing phase. In the six-minute WT, results indicated an approximate 8% reduction in the metabolic cost of transport when wearing the developed KAEGO. However, this study has some limitations. The sample size was small and focused on specific types of gait impairments. Future studies will include a more diverse group of participants to validate the KAEGO's effectiveness across a broader spectrum of hemiplegic patients. Additionally, long-term studies are necessary to assess the device's safety and durability, especially in varied and challenging real-world environments. Moreover, for further clinical effect analysis, we plan to use traditional camera-based motion analysis techniques to quantitatively compare the effects of interventions before and after gait training with the orthosis and to focus on assessing improvements in gait balance. For the practical implementation of the KAEGO for wide use in everyday life, it is crucial that the device is easy for patients or caregivers to wear. It should offer simple adjustability of assistive force and robust durability for long-term use. Furthermore, reducing and redistributing the device's weight is essential to minimize its impact on patients. Ensuring the device's reliability and safety to prevent malfunctions is also critical.