## 5 Discussion and Conclusions  
In this paper, a new user interface for a powered exoskeleton, the WalkON Suit, for complete parapelgics was introduced. The WalkON Suit is a robot developed for complete parapelgics and aimed at allowing the wearer to walk freely in the outdoors and had showed its possibilities through events such as Cybathlon 2016 and the Pyeongchang Paralympics Games 2018. Therefore, the WalkON Suit is not a rehabilitation device for short-term or long-term treatment effects in medical use, but rather a device that allows people to do their daily activities. With the proposed powered exoskeleton, a complete paralysis patient will be able to improve his/her quality of life by obtaining a feeling of walking, gaining confidence and participating in social activities. As a person with complete spinal cord injury can neither move, nor sense the lower limb, it was mandatory for the users of the  
Figure 12: Actuation torque of each joint for one gait cycle. Positive values represent joint flexion torques, and negative values represent joint extension torques. LH, LK, RH and RK stand for the left hip, left knee, right hip and right knee joints, respectively. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Trial** & **Phase** & **LH** & **LK** & **RH** & **RK** & **Total** \\ \hline \multirow{2}{*}{1} & LSW & 54.25 & 22.77 & 95.27 & 49.92 & 222.2 \\  & RSW & 103.4 & 63.78 & 24.76 & 15.47 & 207.4 \\ \hline \multirow{2}{*}{2} & LSW & 63.60 & 36.80 & 86.33 & 51.53 & 238.3 \\  & RSW & 100.8 & 63.35 & 40.78 & 32.49 & 237.5 \\ \hline \hline \end{tabular} RMS: root mean square, LSW: left leg swing, RSW: right leg swing, LH: left hip, LK: left knee, RH: right hip, RK: right knee.  
\end{table} 
Table 3: RMS joint torque of walking motion (Nm)previous version of the WalkON Suit [29] to observe their leg movements continuously. Moreover, the conventional UI utilized a small display installed on the crutch or on the chest, which required looking down when operating the powered exoskeletons. For these reasons, the user of a powered exoskeleton had to look down frequently, which caused gait instability, reduced walking speed and shoulder and neck pain. Therefore, in this paper, a new user-interface (UI) of a powered exoskeleton for complete paraplegics was introduced. The proposed UI system consisted of two tact switches and a display installed on the crutch and a head-up display based on glasses with a see-through display (STD). Different technologies may also be available for detecting the gait intentions of people, such as EMG and foot pressure patterns, which are more suitable for people with partial impairment in walking ability, The foot contact status may be indicated by a visual, tactile or auditory interface, as important information indicating that the wearer of the robot is ready to begin the next step. [PERSON] et al introduced a long-term gait training protocol using a combination of virtual reality training, visual-tactile feedback training, powered exoskeleton training and robotic body weight support (BWS) gait training on a treadmill [26]. However, the effects of single training in tactile feedback, virtual-reality training or exoskeleton training, respectively, have not been clearly verified yet. Many studies have shown that it is possible to use a brain-machine-interface (BMI) for control of robotic exoskeletons [35; 36; 37; 38]. Although the methods listed above provided powered exoskeletons with the possibility to interact with humans in a more sophisticated way, they are not yet reliable for complete paraplegics in practice. According to the authors' experience, the best user interface for each paraplegic user may be highly dependent on the personal preference of the individual. For example, complete paraplegics who have completely lost their proprioception, like the human subject who participated in this research, are very sensitive to the reliability of the robot system. When a robot does not recognize a command (i.e., the motion intention) on occasion, they become very nervous.