This is a new long-term robot project I have been working on for the past couple of months. It is a general purpose indoor robot, that will work as a platform for experimentation. When designing this robot, I have tried to think about and improve everything I have learned from previous robot projects I have made. But this robot will also feature some new stuff I have not tried before. Some of the key features if the robot includes:
Stepper motor based four-wheel-drive skid-steering drive system
Big Li-Ion battery
A lot of custom 3D printed parts
Heavy duty bumpers, large ground clearance and large foam wheels
Raspberry Pi main computer
Arduino Due for controlling low-level peripherals
Scanning Lidar sensor
Probably a Raspberry Pi camera module mounted on a pan/tilt system
So far, only the majority of the mechanical work is done. Here are a few images, click on them to make them larger:
Made a video of my indoor robot, reading and reacting to different sings using Raspberry Pi, camera and OpenCV. The Raspberry Pi sends data about which sign it is detecting using serial, then the Arduino controlling the robot reacts and performs different pre-programmed manoeuvres.
Made a new video demonstrating how my Arduino based balancing robot can enter balancing mode by itself. The video also shows the robot doing basic obstacle avoidance using its tree ultrasonic rangefinders. The obstacle avoidance if currently done by one of the Arduinos, but this a typical high level function that will later be handled by the Raspberry Pi.
I have made some progress with the self balancing robot. The speed of the motors is now controlled using two cascaded PID regulators. One regulator adjusts the speed of the motors to maintain a setpoint angle. The other PID regulator adjusts this setpoint angle according to a setpoint speed. This new control system allows the robot to return to its original position when disturbed. The robot can also find a new angle for balancing if the center of gravity is moved, or the robot is standing on an inclined plane.
In this video I use the Raspberry Pi for a very basic form of remote control. I connect to the robot using SSH, then I run a serial terminal program on the Raspberry Pi to send ascii characters the the main Arduino. The video also shows an example of video and photo quality from the Raspberry Pi camera.
The three ultrasonic distance sensors and the tilt servo for the camera module are not connected yet…