Outreach Project
NASA Aerospace Academy - Rover Workshop at Elizabeth City State University (ECSU)
Project PI: Dr. Kuldeep Rawat(ECSU)
Workshop Conductor: Dr. Walter Deal, Emeriti Associate Professor(ODU)
Workshop Conductor: Dr. Steve Hsiung, Professor(ODU)
Workshop Conductor: Dr. Feng Jao, Associate Professor(ONU)
Mechatronics is a specialty field of engineering and technology that integrates mechanical, electrical, and human factors design functions in programming and controlling the operation of a product used in an industrial system or consumer product. It is an evolutionary stage in the progression of engineering design to produce the products and systems used in modern societies. Examples of these systems include the operation and control of today’s “smart” automobiles, appliances and entertainment products. additionally, we see automated braking systems that sense cars and objects in their driving path and self-driving cars.
The Rover Workshop will provide hands-on experiences in assembling and programming a mobile robot to encourage interest and awareness in STEM-related studies for the 9th -12th grade teachers that are participating in this workshop offered through the NASA Aerospace Academy site at ECSU. The objective of the Rover Workshop is to participate in activities that can provide student awareness, interest, and motivation in STEM-related courses and careers. The teachers will experience activities in constructing, assembling, and programming a 3D printed remotely controlled Rover Robot with vision guidance capabilities.
The participants will test, evaluate, and compete in a culminating Rover activity using their remotely guided video camera-equipped Rovers to locate and identify a hidden object. Additionally, science-related activities will be demonstrated using the Robot Rover that includes digital measurement of temperature and humidity, light, speed and velocity, and ultrasonic distance measurement that may be used to augment classroom activities.
Rover Control
Rover Multi Axis-Camera Control
3D Files
3D Production Files for Rover
3D Printer
Preparing the 3D Printer
3D Multi-Axis Camera
3D Files for Multi-Axis Camera
Rover Chassis
Assembling the Rover Chassis
Assemble wires
Rover Robot wiring Assembly
Arduino
Arduino Sample Programs
program Arduino
Program Arduino
Camera Setup
Install APP and setup Camera
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 installed under the platform. 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 battery holder is installed under the platform and between the two side plates.
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
Inventor demo file during workshop - Save as an stl file
Dremel Digilab 3D Slicer - save stl file to gcode
Production Files for Multi-Axis Camera
Multi-Axis Camera
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_1_15_20.stl View/Download
Camera Stepper Mount File
Filenames:
Stepper-top-mount_1_15_20.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:
Stepper-top-base_1_15_20.stl View/Download
Camera-base_1_15_20.stl View/Download
Camera-ring_1_15_20.stl View/Download
Rover Robot Wiring Assembly
install wire at DC Motor Shield board
Install wire from battery to power switch
Install wire from battery to power switch - ground wire (black)
Install wire from power switch to DC Motor Shield Board, make sure your swtich set the "Off"
Connect the wire, make sure Red wire is at top
Connect the wire at the other side, make sure Red wire is at the bottom and connect the end to the DC Motor Shield Board. (black wire to ground)
install drive train motor wires to the DC Motor Shield Board.
install cable, make sure the ground cable is at the outerend.
install cable at the other side, make sure the ground cable is at the outerend.
connect the other end of the cable to the DC Motor Shield Board.
connect cables to the DC Motor Shield Board.
connect the other end of the cable to the DC Motor Shield Board.
View of the connection on DC Motor Shield Board
View of the connection on DC Motor Shield Board
Preparing the 3D Printer - ROBO R1
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
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 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
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.
Slide the battery shelf under the platform (between the two motor side plates)
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.
Add HeSai boards to the 3D printed Camera base.
install stepper motor and limit switches at the top of the camera base.
install stepper motor to the Camera Top Base.
install limit switches to the Camera Top Base.
install Camera Ring 3D part.
Attach heat sink
Attach heat sinks to controller boards
Continue to the Assemble Wires section to complete the assembly
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 Rover_ECSU_3-13-2020.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 Rover_ECSU_3-13-2020.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
