**3.5 Human-machine interface**

The final requirement for the autonomous wheelchair is a user interface that allows the human user to send the desired goal point on map. After this selection, the wheelchair plans its trajectory and tracks the path continuously. Instead of

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**Figure 7.**

*Conversion of a Conventional Wheelchair into an Autonomous Personal Transportation Testbed*

*DOI: http://dx.doi.org/10.5772/intechopen.93117*

*Power distribution of autonomous wheelchair.*

*Overall communication architecture of the system.*

*Rear view of autonomous wheelchair and screenshot of the human-machine.*

**Figure 5.**

**Figure 6.**

**Figure 4.** *Computational hardware of autonomous wheelchair (drawer is open).*

*Conversion of a Conventional Wheelchair into an Autonomous Personal Transportation Testbed DOI: http://dx.doi.org/10.5772/intechopen.93117*

**Figure 5.**

*Service Robotics*

**3.3 Power distribution**

**3.4 Communication structure**

**3.5 Human-machine interface**

power requirements before the decision of autonomous driving algorithms, we will analyze the performance of each hardware. At the end, one of these boards can be removed from system or can be used together depending on their performance. **Figure 4** illustrates the computational hardware mounted in a drawer, which is designed for the chair specifically. The gray protection boxes for Jetson TX2 and

The main energy source of the system consists of two serial connected lead acid batteries. The main voltage level for the traction motors is 24 V. On the other hand, there are several other components for autonomous operation. In order to provide the appropriate voltage level for each sensor and computational hardware, DC/ DC converters are used. **Figure 5** illustrates the power distribution scheme, including voltage levels, of the wheelchair components. An additional electric circuit is designed for power distribution using appropriate connectors fuses. DC/DC

Until now, all the electronic components have been shown and their purpose of use has been explained. In order to use all these devices properly, a secure communication network needs to be constructed. Each component has different interface in the system. For this reason, there are five different communication protocols such as Ethernet, USB 2.0, RS232, USB 3.1, and analog signals. **Figure 6** illustrates the overall communication architecture of the developed autonomous wheelchair.

The final requirement for the autonomous wheelchair is a user interface that allows the human user to send the desired goal point on map. After this selection, the wheelchair plans its trajectory and tracks the path continuously. Instead of

Upboard, which are produced by 3D printer, can be seen from **Figure 4**.

converters and the designed circuit can be seen from **Figure 4**.

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**Figure 4.**

*Computational hardware of autonomous wheelchair (drawer is open).*

*Power distribution of autonomous wheelchair.*

**Figure 6.**

*Overall communication architecture of the system.*

**Figure 7.** *Rear view of autonomous wheelchair and screenshot of the human-machine.*

providing only the goal point, the user can set the waypoints to be tracked, by touching the desired coordinates on the map. Additional features of this interface are to send an emergency signal to the chair and to see the critical information such as wheelchair's velocity and actual position on map. The interface software is designed on a touchable tablet PC. Assembled form of the tablet on wheelchair and a screenshot from the designed interface software are shown in **Figure 7**.
