Outreach Project
MARRS Summer Workshop at Jackson State University (JSU)
Project PI: Dr. Mehri Fadavi, Professor(JSU)
Workshop Conductor: Dr. Walter Deal, Emeriti Associate Professor(ODU)
Dr. Steve Hsiung, Professor(ODU)
Dr. Feng Jao, Associate Professor(ONU)
There is significant interest in STEM and STEM-related teaching, learning, and career opportunities. Science, technology, engineering, and mathematics are fundamental to the technological field called mechatronics. Mechatronics integrates engineering principles and methods with the fields of mechanical and electrical engineering and computer programming in prototype designs of technical products that used in our daily live.There is significant interest in STEM and STEM-related teaching, learning, and career opportunities. Science, technology, engineering, and mathematics are fundamental to the technological field called mechatronics. Mechatronics integrates engineering principles and methods with the fields of mechanical and electrical engineering and computer programming in prototype designs of technical products that used in our daily live.
The Jackson State University MAARS 3D Printing and Rover design project is directed toward the explorations with a 3D printer, electronic controls, and computer programming to print, assemble, and program a Robot Rover to be operated via remote control televised video-assisted operation.
The followings are detail descriptions of CAD designs, 3D printing mechanical parts, assembling and connecting electronic components, and programming an Arduino microcontroller development board. Special skills gained include understanding the 3D design and printing processes, working with electrical and electronic circuits, developing C+ like programming skills. The purposes of the workshop are directed toward activities that enhance STEM educational endeavors and provide insights and awareness of technical careers in mathematics, science, technology, engineering and related careers.
To access workshop PowerPoint file, please click here to download the file
3D Files
3D Production Files for Rover
Multi-Axis Camera
Files for Multi-Axis Camera
Arduino
Arduino Sample Programs
Assembly
Rover Robot Assembly
3D Printer
Preparing the 3D Printer
Rover Chassis
Assembling the Rover Chassis
Connect All
Connect and Program Arduino
Camera Setup
Install APP and setup Camera
Rover
Summary
The programming of the Arduino UNO is the standard procedure typical in programming the Arduino boards and other microcontrollers using and integrated development system (IDE). It is important to note that the Arduino uses serial port for communication between a computer and the Arduino UNO board for a programming connection. This process also uses the power from of the USB port of the computer to power the Arduino. When the Arduino is connected to a USB port the battery supply to the Rover should be disconnected before programming the Arduino.
The Bluetooth module uses the same serial com port for connecting and programming the Arduino communication processes, so they cannot coexist – remove the Bluetooth module when programming! The other notes are the battery and connector polarity and com port Rx & Tx connections must be correctly followed to prevent any damage to the modules. Look at the photo example closely!
The gear motor assembly pairs are wired together as a “left drive” and “right drive.” When the Rover is signaled to move in a forward direction, both the right and left motor assemblies should turn in the same direction. If they do not, the solution is to reverse the one of the motor connectors Arduino motor driver board.
Looking Ahead
The 3D Rover Robot opens up a wide range of future experiments and activities in the engineering and STEM fields. Problem solving, mathematical and critical thinking skills are challenged through the design and development of 3D printed models and programming in a C-like programming language.
The building and programming the Rover Robot models provide insights into the kinds of skills and knowledge used in technical fields in developing prototypes using leading-edge production and electronic technologies. There is considerable interest in robot, wireless communication, autonomous technologies for industrial, military, and consumer applications. Education and study related to these fields require strong mathematical and science backgrounds. Activities such as the Rover project may stimulate interest and encouragement for young women and minorities to investigate careers in engineering and science in military and civilian areas.
3D Production Files for Rover
The Rover chassis platform provides all mounting holes and cutouts to support the Arduino circuit board, DC motor control board and power switch. The battery holder is attached with double-sided tape. It is important to note that 3D printing relatively large surface areas may have a tendency for the edges to curl. This is more noticeable with open printers and non-heated bed printers.
The Rover side bracket plates are attached to the chassis platform with machine screws. The brackets are symmetrical – print two (2) for right and left sides.
Inventor demo file during workshop - Robot Head
Production Files for Multi-Axis Camera
Rover Chassis Platform
Multi-Axis camera assembly includes four parts. The base supports the stepper motors top rotating plated and camera. The top stepper bracket attaches to the top rotating plate and bottom stepper. Machine screws and set screw are used to fasten the components together. The printer files are listed below.
The camera base plate is shown at the top left. The top right shows the top stepper base and the lower left is the top stepper mount. The lower right is the camera mounting plate. The MiniCam has a builtin magnet that attaches to an ahesive-backed plated attached to the camera plate. (Filename: multi-axis-printed-parts-small.jpg)
Camera Base Plate
Filenames:
camera-base-plate-6-5-15-2019.stl View/Download
Camera Stepper Mount File
Filenames:
top-stepper-mount-5-31-2019.stl View/Download
Multiple Camera Files
In some cases, we can also print multiple files at once. This may save you some time in printing, however, in some cases the printer may become too warm and cause deformaties in the final product.
Filenames:
camera-mounting-plate-5-29-2019.stl View/Download
top-stepper-base-5-20-2019-rev.stl View/Download
Rover Robot Assembly
The Rover Robot assembly process is divided into three groups.
1. The chassis group consists of the Rover platform and Rover motor mounting and side plate brackets. These parts are assembled using machine screws.
2. The second group is the drive train components – wheels and motor gearboxes. The wheels are a friction-fit on the gearbox shaft. Note that there are “flats” on the motor shafts and the wheel must be rotated to the correct orientation to slide on to the shaft. The wheel should fit snuggly when sliding on to the motor shaft.
3. The third group of components is the electronics and battery supply. The Arduino board is attached to the chassis platform using socket head screws. Small spacers are placed on the bottom side to the Arduino when securing the screws. The Arduino programming connector is oriented toward the back of the Rover chassis. The power switch is mounted in the chassis cutout and the wiring harness connection made. It is important to connect all wires correctly. Incorrect wiring will damage the electronic components.
4. The second sworkshop session will additionally, build the Multi-Axis MiniCam TV assembly that is mounted on the front of the Rover chassis platform with machine screws. The MiniCam Multi-Axis assembly will be tested and “homed” with a test program as part of the Multi-Axis set up.
Power for the Rover is supplied by two 18650 Lithium batteries. Please us Caution in handling these batteries! The batteries must be charged in a special battery charger. The batteries must be installed in the Rover battery holder correctly. Do not short circuit the batteries. Have your workshop coordinators check you Rover connections BEFORE installing the batteries!
The Chassis Group
The Rover for the workshop is packaged with all components needed to assembly. Instructions for assembling the rover can be found on the Rover workshop web site. Alternatively, they can be printed and assembly can be completed without an Internet connection.
The 3D Rover robot provides an entry-level flexible platform to build mechatronic skills with 3D printing technologies, programming, electronic control, and mechanical systems.
There are three major groups of components. These include the mechanical parts, drive train and electronic components.
The mechanical parts include the Rover platform for mounting the electronic control components, batteries, and Bluetooth transceiver.
There are 3D printer files (stereographic STL) for each of the printed parts. These include the Rover platform, and right and left motor side brackets. Machine screws and nuts are used for assembly.
The battery holder is attached using double-side tape.
Basic tools are used to assemble the Rover and Multi-Axis camera assembly. These tools include a small Philips screwdriver (No.1 or pocket screwdriver), needle nose pliers, and Allen wrenches.
The Drive Train Components
The Rover drive train consists of four gear motor drives with individual wheels. The wheels are pushed on and are a “light” friction fit. The servo is mounted using four plastic spacers and socket head machine screws.
The Electronics and Battery Supply
The electronics components are Arduino UNO board, DC Motor Shield board, Ultrasound Module, Bluetooth Module, Lithium Batteries & Holders & Power Switch, USB Cable, and Wires
There are two 3D STL printer files required to print the chassis parts. These files are:
- Platform (rover-MAARS-platform-rev-6-6-2019.stl)
- Two Motor Side Brackets (Filename: rover-quad-motor-bracket-6-6-2019.stl )
Preparing the 3D Printer
The Rover Summer Workshop used the Robo R1 3D printer for printing all Rover chassis parts and sensor mount. Tests on both ABS and PLA were made to select the most appropriate material. It was found that the PLA (requires lower temperature) material performed best with the ROBO R1 printer. The physical properties of ABS and PLA proved to be acceptable for all of the printed parts.
It is important to follow the manufacturer recommendations on preparing the 3D printer for printing to avoid delays and errors.
The Robo R1 employs a heated bed that must be coated with a base adhesive material before beginning a printing project. A glue stick is the preferred material. It was also found that the printer bed did require cleaning and recoating of the glue-stick adhesive occasionally. Extrusion temperatures and flow rates affect the quality of the printed product and vary according to the material type. The printer bed temperature must be appropriately set.
There are number of different brands of low to moderate cost 3D printers. The workshop project incorporated several different models of 3D printers. A ROBO 3D R1, XYZPrinting’s DaVinci 1.0 and Dremel DigiLab 3D45 printers were used to produce the printed parts.
Getting Started
Typically, the printer bed is coated with a glue stick with a thin uniform adhesive layer. An effective coating provides good adhesion for the printed part and minimizes curling of large area parts. Please note that the printer bed must be cleaned and re-coated after several prints. In most cases glue stick compounds are water soluble.
Either ABS (Acrylonitrile Butadiene Styrene) or PLA (PolyLatic Acid) may be used for the Rover project. The filament is inserted and installed in the printer according to printer instructions. It is important to observe the temperature settings and extrusion rates for the material selected.
The stereolithographic (stl) files were placed on an SD memory card for convenience and to eliminate “printer time-outs.” Newer printers such as the Dremel Digilab 3D45 include network and Cloud printing capabilities.
The 3D printing process is very slow on large items such as at Rover chassis and generally cannot be accomplished in a typical single classroom period. Several parts of the Multi-Axis assembly were small enough to be printed during an average class period.
Assembling the Rover Chassis
After all of the 3D printed components have been made and ready for assembly, it may be necessary to “clean” the 3mm holes using a 3mm or 1/8” drill to provide easy assembly.
The motor side plates are attached to the Rover platform using two 1/2” 4-40 Philips head machine screws and nuts. It is advisable to have a small bottle of nail polish or model paint the serve as a “thread locking” material.
Orient the motor side plate with the mounting flange toward the center of the Rover platform.
Tighten the nuts securely but do not over-tighten the machine screws as it may crush the printed parts.
Assemble the second motor side plate as accomplished previously. Note which side the mounting flange is oriented. Assemble this motor side plate with the mounting flange toward the center of the Rover platform.
Attach gear motor drives to Rover side plate using 4-40 X 1-1/4” machine screws and nuts. The motors should be mounted with the wire-side out. Place nuts on the inside of the motor side plates.
Attach the last pair of motor units to the other side plate. Note that the motors are wired together. Each pair of motors are connected together to turn in the same direction. When the motors are properly connected, all four motors will turn in the same direction in a forward or reverse mode.
Attach the Arduino UNO controller board using three 4-40 X 1/2” socket head machine screws with plastic spacers and nuts.
Do not over-tighten screws. The programming USB “B” socket must face outward (away) from the Rover platform.
Attach the motor shield to the Arduino UNO board. Use care in aligning the shield orientation and connector pins.
The screw terminals are oriented toward the silver USB connector on the UNO. The shield pins will not “seat” all the way into the UNO connector sockets.
Attach the battery holder with “double-sided” tape. The battery hold wires are facing the back end of the Rover. The “free ends” of the battery wires are attached to the mini-slide switch.
The motor wires are connected in pairs with red-band wires connected to the Motor-A and motor-B terminals on the motor control board. It may be necessary to change the orientation of the motor wire connectors if one pair of motors turn in the wrong direction.
When the Rover is running in a forward direction, both motors should turn the same way.
Use care in tightening the screws. Do not over tighten!
The battery wire connector is connected to the screw terminals on the side of the motor shield. Use caution connect the RED wire to the VMS (right side terminal) and the BLACK wire to the “GND” terminal (left side terminal)
The shafts on the Rover motor gear boxes have “flats” on the shaft. The flats on the shaft must be aligned correctly so that the wheels will slip on the shafts snugly. Hold the yellow motor gear box securely when attaching the wheel.
Attach the remaining three wheels. Hold the driver motor securely when attaching the drive motors as the motor side support brackets may break.
The Bluetooth radio must be inserted into the Bluetooth socket with the correct orientation. Examine the photo closely and you will see the proper location and orientation of the Bluetooth radio. The “chip side” faces the back of the Rover!
Caution! Inserting the radio in the wrong socket or the wrong way will damage the radio!
There are two red wires that are connected to the Rover power switch as shown in the photograph. Connect either wire to either pin on athe switch.
The Rover assembly is complete. Perform the following checks.
- Chassis assembled
- Arduino installed
- Motor Shield installed
- Power switch installed
- Switch assembly installed
- Switch wiring correct
- Motor wiring correct
- Battery holder attached
- Wheels attached
- Assembly Check by instructor
Connecting and Programming Arduino
Caution! When programming the Rover Arduino board the Rover power switch must be OFF!
The Bluetooth radio must be removed to program the radio. Turn the power OFF when removing the Bluetooth radio or a programming error message will be displayed.
Plug in the Arduino programming cable. A programming cable is used to connect the Rover Arduino to a computer USB port. The computer should automatically recognize the Arduino UNO board.
The programming interface (IDE) should recognized the Arduino UNO board. If it does not recognize the Arduino it will be necessary to select Tools on the menu then select Board. The correct board is Arduino/Genuino UNO.
Set the correct COM port. It may be necessary to select the appropriate COM port. The COM port may be selected using selecting Tools on the menu bar. Additionally, Windows 7 or 10 may install a special CH341 driver for the Arduino board.
Programming Arduino for the first time. Use the Center Servo and Motor Test program to verify assembly of Arduino Rover. The filename ismotor_test_summer_workshop_2019.ino. This program should move and center the ultrasonic sensor servo and run the drive motors forward and backwards. There are comments in program code to describe functions and operation.
Bluetooth Rover
Bluetooth Rover – The Rover can be operated using the Bluetooth transceiver module for remote control operation. Plug-in the Bluetooth module into the motor driver board. Caution! Connect the +5 volt wire from the Arduino to the Vcc terminal on the transceiver. Connect the GND wire to the GND terminals. The Arduino Rx is connected to the Tx transceiver and transceiver Tx is connected the Arduino Rx.
Carefully, place the Bluetooth transceiver module in the slot next to the Arduino board.
Next, connect the programming cable to a USB port and Arduino. Open and upload the file named motor_test_summer_workshop_2019.ino.
Caution! Allow the program code to compile and upload to the Arduino. The uploading process can be seen at the bottom of the programming screen.
The smart phone Bluetooth Robot Control App (ArduinoRC) may need to be installed to control the Rover.
Turn the Rover power switch on and run the ArduinoRC App. It is necessary to “pair” the transceiver and smart phone Bluetooth connection on the first use. The passcode is “1234.”
The Bluetooth transceiver and phone must have established an connection to pair. Each BT transceiver has a unique ID. The Red LED indicates the status of the Bluetooth connection. When the LED is flashing, it is waiting for a connection. The transceiver LED will stop flashing when a connection is made.
Once the Rover is “connected” to the ArduinoRC App, use the “controller” interface to control the Rover. The arrow key actions are forward, reverse, left and right turn and stop. The keys do not need to be continuously pressed.
The trial and testing phase begin after the Rover Robot has been programmed for Bluetooth control operation. These kinds of applications simulate real-world engineering and STEM problems faced by engineers and researchers.
There are sections of the Arduino code that provide the capability to change the speed of the Rover to make it easier to control but travel and maneuver easily. for both the autonomous and Bluetooth programs that There are “constants” in the Aarduino program where you may set the speed using the “analogWrite” function and a pwm value between 0 and 255 (maximum speed) to set the Rover speed. As the speed of the Rover increases it may become difficult to “drive.” Conversely, if the pwm value is too low the Rover may not have enough power to move and navigate.
APP Installation for Multi-Axis Camera
Download and install APP
