There’s a variety of measurements, experiments and applications that you can do with photonic modules. But to extent the breadth of usage of camera and laser modules, a mobile platform is strongly recommended. As we march towards a generation of robots and automation, the importance of mobile robot platforms cannot be overemphasized. The mobile platform we have can carry heavier and a larger amount of modules with the help of 24V brushless motor and the 50 x 25 sole plate we selected. The 24V motor has its built-in driver and speed reduction gear, allowing the mobile platform to perform more subtle actions.

 

We selected a raspberry pi 3 model to help us realize the mobile platform and designed our programs according to the pins that we connected. Using the ROS (robot operating system), we can access all kinds of libraries and modules to remote control the mobile platform on our laptops. There is more space for you to operate if you are looking for a more complex or custom coding design.

 

This 24V motor has quite a different property compare to regular DC motors. We discovered that the negative port of the power supply should be grounded so that the motor could operate. But once the negative port is grounded, the PWM feature works in an opposite condition. Instead of the behavior that the higher the duty cycle, the higher the rotation speed, now the motor has lower speed when the duty cycle goes high.

 

The black case on our mobile platform is the temporary battery we selected to supply the power of our motors. It can supply DC 36V because it’s mainly used on electric bicycles. Unfortunately, the motors can only hold 24V so we inserted DC boost converter module for both motors. We also mount a temporary mobile power bank for raspberry pi on the platform.

 

Since this is a prototype of our robot mobile platform, we haven’t designed the wire traces and counterweight. You can see that some of the wires are too long and that two terminal blocks and a temporary breadboard are installed on the platform.

We are looking forward to reduce the space occupied by the batteries and the boards to 20% of the current layout, expecting a more compact mobile platform.

 

We establish the communication between the PC and raspberry pi via ROS nodes, assigning the PC end to be the Master node in order to publish the commands. In contrast, the raspberry pi end subscribes to the PC end, receiving the commands.