T-Quad

T-Quad with 4 x Mecanum wheels

T-Quad can be used in different configurations.

On the left, we uses 4 x Mecanum wheels. With these wheels, the robot can not only go forward, backward and turn, it can also translate right or left ! In fact, depending on the combination of rotation speed of the four Mecanum wheels, any kind of motion is possible.

On the right, a Raspberry Pi is added to the robot. You can use it to add high performance communication features (Wifi communication, real-time video streaming) or high level control (obstacle avoidance, object recognition,...) with different languages (Python for example).
You can use almost any kind of mini-computer (not only a Raspberry Pi ; it can be also, for example, a BeagleBone Black, a pcDuino, a C.H.I.P., an Odroid,...) provided that it has an i2c link, whatever the voltage level (3.3V or 5V).

T-Quad with 4 x Mecanum wheels and Raspberry Pi

T-Quad with 2 x normal wheels and ballcaster

T-Quad can also be used with standard wheels.

On the left, it works in a classical way with a ballcaster.

On the right, you can see the self-balancing configuration. T-Quad integrates various sensors (see below) in order to perform this kind of advanced control.
We also added a nice feature: the ultrasonic sensor is mounted on an manually adjustable angle bracket. Whatever the orientation of T-Quad (horizontal or vertical), you can use this distance sensor (and also the optional Webcam, mounted on the same bracket) !

T-Quad in self-balancing mode

T-Quad is a robot Shield for Arduino Mega 2560 with a lot of features:

• 4 x DC Motors 6V with incremental encoders
• Current measurement on the 4 motors (or physical parameters identification)
• MPU9250 (3-axis accelerometer, 3-axis gyroscope, 3-axis magnetometer)
• HC-SR04 (ultrasonic sensor for distance measurement) with adjustable angle mounting bracket
• 3 x infrared sensors for line-following applications
• Various wheels configurations:
  • 4 x mecanum wheels (holonomic wheels allowing translation in any direction)
  • 2 x standard wheels + ballcaster
  • 2 x standard wheels (self-balancing)
• OLED screen for advanced display of messages
• 2 x switches for managing easily 4 different working modes
• 7.4V LiPo or 7.2V NiMH battery
• Battery voltage sensing
• XBee socket for simple Wifi and/or Bluetooth communication
• 2 x i2c socket (3.3V and 5V)
• Powerful 5V / 1A DC-DC converter for optional external devices
• Optional advanced communication features with additional mini-computer
  • Transparent acrylic mounting plate
  • Webcam

Various activities are possible (open-source Arduino sketches and mini-computer programs):

• Identification of DC Motor parameters (from open-loop current and speed measurements)
• DC Motor speed control
• DC Motor positiion control
• Remote control of robot in "mecanum wheels" configuration
• Remote control of robot in classic configuration
• Remote control of robot in self-balancing configuration
• Automatic switch of control mode between classic and self-balancing configuration (verticality detected by accelerometer)
• Line following (using infrared sensors)
• Lateral translation with front wall distance following (using ultrasonic sensor)
• Obstacle avoidance (using ultrasonic sensor)
• Uphill following (using accelerometer)
• Following of magnetic orientation (using magnetometer)
• OLED screen management (display of various kind of messages depending on sensors values)
• i2c communication with IMU (MPU9250), an (optional) mini-computer or any kind of external device
• Real-time video streaming from (optional) Webcam through (optional) mini-computer
• Simple use or creation of custom control and data display dashboards using MyViz
• ... (non exhaustive list)