Difference between revisions of "Open Source Electric Drive Cube Robot"

Outline

• Project: Open Source Electric Drive Cube Robot
• Objective: To make a Cube Robot car
  • Can be controlled by Joypad.
  • Also can support Bluetooth APP control.
• Difficulty: Middle
• Time-consuming: 2-Hour
• Maker: PKJ

Bill of Material

Bill of Modules(Joypad mode)

Bill of Module(Bluetooth mode)

Other Material

Principle of the Experiment

• There are various kinds of Robot cars, such as robot car of tracking, barrier, Bluetooth control, which with different functions and need to adopt different sensors.
• However, all those Robot cars are basically controlled in the same way, that is, moving in four directions.
• Here we adopt two-wheel drive structure. By control the rotation of two wheels, we can achieve moving forward and backward, or spinning. Of course, it needs auxiliary wheel to keep balance.
• This car has a simple structure, including wheels, body and control system.
  • 1)The wheels adopt two speed-down motors with large torque, which can have PWM speed adjustment to make sure easy control.
  • 2)The body of the car adopts wood with a size of 8cm*8cm*8cm.
  • 3)The whole control system contains four parts:

• CPU
  • Adopt Microduino-Core as the core. Just like the CPU of a computer, it can analyze and process complicated things.
• Wireless commmunciation
  • Adopt Microduino-nRF24 wireless communication scheme with fast communication response and the control range of about 50m in the open area.
  • Or adopt Microduino-BT wireless communication scheme, which can work with phone APP to directly control. The control range is about 20m in the open area.
• Motor control
  • Adopt a group of built-in DC motor drive unit on the Microduino-Robot, and a unit can drive two motors.
• Power supply system
  • Adopt a built-in sing-cell Li-ion battery management unit on the Microduino-Robot to manage charging and discharging function.

Program Download

• Cube Robot Code: Robot_Microduino

Programming

• Stack Microduino-Core and Microduino-USBTTL together, then use the USB cable to connect the USBTTL module for program uploading.
  • Note: Please upload programs before stacking all modules together.
• Open Arduino IDE for Microduino development environment. (For the buildup, please refer to: AVR Core：Getting started )
• Make sure the right board(Microduino-Core Atmega328P@16M,5V) and the relevant port number(COMX)
• Open the " Robot_Microduino.ino " program in the downloaded projects.
• Click "→" and upload the program to the development board.

Installation

• Step1:
  • Adopt Motor fixation base to fixate the two N20 gear motors on the Structure-A1.
  • Assemble the Wheels, tyres and Couplings, then install them with the fixated N20 gear motor.

• Step2:
• Insert Structure-A2 into the slot of the two sides of Structure-A1.
• Use two Structure-A4 to fixate the bottom of Auxiliary wheel on the Structure-A3.
• Prepare Structure-A3 and Structure-B1 from up to down as the picture shows below.

• Step3:
• Fixate theStructure-B2 and Structure-C1 on the two sides.

• Step4:
• Stack the following modules on theMicroduino-Robot.
  • Core module: Microduino-Core
  • Communication module:
    • Under Joypad mode, the communication module is Microduino-nRF24（Install the antenna firstly）
    • Under Bluetooth mode, the communication module is Microduino-BT
• Connect Battery to the Battery interface on the base of Microduino-Robot.
• Connect two N20 gear motors to the A.A/A.B motor interfaces on the base of Microduino-Robot.
• Fixate Microduino-Robot onStructure-B1 with screws.

• Step5:
• Fixate Auxiliary wheels on Structure-C2 with two Structure-C3.
• Insert the Structure-C2 to the front side.

• Step6:
• InsertStructure-D2 to the back side and stick the antenna.
• Put the Structure-D1 on the top and by here, congratulations! You just completed the installation.

Instructions of the Remote Control

• If stacking the nRF module and start, the system will enter the Joypad control mode by default, otherwise, it'll enter the Bluetooth mode.

Guide for Joypad Control

• For the installation, you can refer to the following page: [1]

• Joypad Communication Mode Configuration *
• For the mode configuration, you can refer to the following page: Communication Protocol Configuration
  • When we use Microduino-nRF24 as the communication module, for the Joypad, it can choose nRF mode correspondingly.

• Instruction of Joypad Battery Use *
• For the battery use, you can refer to: Power-on via Battery

Guide for Bluetooth Control

• First of all, download remote control APP（Android）: File:MTank.rar
• Confirm that the version of your phone is above Android 4.3 and the Bluetooth is open.
• Search the Bluetooth device named "Microduino", and connect to it.
• Then you can control it remotely by APP.
• For details, please refer to mRobot

Code Description

• Find the configuration file in " user_def.h ".
• The following codes can configure the channel under nRF mode, which needs to keep consistent with Joypad controller.
• For the Joypad's nRF mode channel configuraton, you can refer to: Channel Configuration of nRF Mode

#define NRF_CHANNEL 70  //nRF channel

• The following codes can configure the throttle and the corresponding steering channel.
• For the corresponding channel, you can refer to: Channel/Operation Description

#define CHANNEL_THROTTLE  2 //Throttle channel 
#define CHANNEL_STEERING  1 //Steering channel

• The following codes can revise the speed ratio of the two wheels.
  • The range is between -1 and 1.
  • Set as -1, the maximum speed ratio, clockwise.
  • Set as 1, the maximum speed ratio, anti-clockwise.
  • If the car cannot go straightly, you should reduce the speed ratio of the lower wheel.

#define motor_fixL 1  //Speed correction (-1 to 1)
#define motor_fixR 1  // Speed correction (-1 to 1)

FAQ

• Q:How to choose Joypad mode or Bluetooth mode for this CUBE robot?
  • A:You don't have to select manually but stack nRF24 module when power-on. The system will enter the Joypad mode by default, or it'll enter Bluetooth mode.

• Q:What type of battery does the CUBE robot support?
  • A:It supports 3.7V 1S lithium battery.

• Q:How to connect the motors?
  • A:You can connect the two motors to the A.A/A.B interfaces respectively.

• Q:Does my phone support Bluetooth control?
  • A:It is supportable for phones of Android 4.3 or higher.