*2.5. Safety Buttons*

Safety is a key issue in wearable robotics, so there are three emergency stop switches (Figure 3): (1) on the left side of the robotized wheelchair; (2) on the back side of the robotized wheelchair; and (3) connected through a wire to the left side of the wheelchair.

By default, there is only one emergency button that kills the exoskeleton power supply from the battery, located on a panel on the wheelchair. However, there is a second plug that offers the possibility of wiring a second button, which allows halting the device from a distance.

To restart the exoskeleton operation after a safety stop, the emergency button must be released and the lit green button of the left panel must be pressed.

The mobile robotic platform has its own emergency button located on the back side of the robotized wheelchair.

To restart the movement of the robotized wheelchair after a safety stop, the platform must be restarted by following the following steps: (1) pressing the green CPU button for 2 s; (2) when the green LED of the CPU button is off, putting the ON-OFF switch in the OFF position; (3) putting the ON-OFF switch in the ON position; this will turn on the platform electronics again; (4) pressing the green CPU button for 2 s; and (5) releasing the safety button.

**Figure 3.** Safety buttons: (**left**) two safety buttons on the left side of the robotized wheelchair for the main CPU; (**right**) one safety button on the back of the wheelchair for the mobile platform.
