Martian Rover Design ProjectEE 1382 / ME 1102 / CSE 1341Fall 2008

Figure 1: Photograph of Martian Rover Opportunity approaching the rim of the Victoria Crater on Mars as captured by the Mars Reconnaissance Orbiter. (http://mars.jpl.nasa.gov/mro/newsroom/pressreleases/20061006a.html)

Object: Design a system capable of locating a target object (colored ping-pong ball on top of 1.5 ft tall 2 ft square pedestal), acquiring the target object, locating a target destination (seperate 1.5 ft tall 2 ft square pedestal), transporting the object to the destination, and returning the robot to its initial location. During the mission you will reside in Mission Control and have remote access of your robot and view imagery from a Mars Reconnaissance Observer camera. Your robot, the target object and destination will all be physically separated from you. Your mission will be timed. You may be asked to complete several missions with various starting positions of your robot and the object. The fastest cumulative time spent performing the missions “wins”.

Timing the Mission:The average farthest distance between the Earth and Mars is 378 Million km. This corresponds to 21 minutes for a signal traveling at the speed of light. Therefore, every time a signal is sent from earth to Mars it takes on average 21 minutes to arrive. For this project, this latency will be calculated in every interaction between yourself and your

robot. You mission time will be the “real” time used by your team to accomplish the task plus 21 minutes for each interaction that you had with the robot.

Materials Provided for the Design:Custom Designed Robot Controller Board with:

2 DC motors with encoders,2 “Strong” Servo Motors (appropriate for lifting “arms”)2 “Weak” Servo Motors (appropriate for “grasping”)Wheel mounts,802.11 network accessImage from the Martian Observer indicating resolving capabilities of camera.Specifications for the pedestals containing the object and its destination.

All materials will be provided the week of October 6th. In the mean time, an instruction manual for interacting with the board and specifications for the motors will be provided.

You will need to provide a list of materials for the robot construction to Necdet Yildrimer (Embrey 034A, nyildiri@engr.smu.edu) prior to the Preliminary Design Presentation to insure that these materials are approved for purchase. You may also use any available materials in the machine shop, subject to Mr. Yildirimer’s approval.

Materials Provided for the Competition:Computer with Labview for Image Processing3.1 Megapixel 802.11 Wireless Webcam looking down on Martian SurfaceComputer to access the webcam and robot card

Timeline: Sept.15 – Introduction to Design Project Oct. 17 – Preliminary Design Report Due at 5:00 p.m. Oct 20 to Oct 24 – Preliminary Design Presentations Nov 13 & Nov 14 – Testing of Design Nov 20 – Competition Dec 2 to Dec 4 – Final Design Presentations Dec 5 – Final Design Reports Due at 5:00 p.m.

Baseline Architecture for Mars Mission:

Martian Rover802.11 access

Martian Observer3.1 Megapixel Camera

802.11 accessAssumed Location of

Automated Control

Mission Control802.11 access

Interactive Control

No Penalty 21 Minute Penaltyper transmission

Martian Rover802.11 access

Martian Observer3.1 Megapixel Camera

802.11 accessAssumed Location of

Automated Control

Mission Control802.11 access

Interactive Control

No Penalty 21 Minute Penaltyper transmission

Figure 2: Layout of Project Assets. Your team will construct the Rover using the provided board. The Observer camera will be provided. The Labview image processing Virtual Instrument (VI) will be assumed to be located on the Observer platform along with any automated control (in practice they will both be present in Mission control, but you cannot physically interact with them and they are not assessed the 21 minute penalty. Your team will be at the helm of the Mission Control workstation.

As depicted in Figure 2, the robot will be in the Martian Field, a 3.1 Megapixel Wireless Webcamera (Martian Observer) will look down on the field, and you will have an 802.11 wireless capable notebook computer in Mission Control to communicate to the Martian Rover and Martian Observer.

Below are some descriptions of suggested modes of operation and their ramifications:

Completely Manual OperationIn this mode of operation, the images from the Martian Observer are acquired into a Labview VI in which the positions of the target, destination, and robot are calculated, as well as the orientation of the robot. At this point the student team instructs the robot to take an action (“Move forward 10,000 clicks”) incurring a 21 minute latency penalty. At the end of the motion, the process begins again with an update to the positional data and a new manual command is given. The lack of automated control simplifies the design, but maximizes the number of 21 minute penalties incurred.

Batches of Manual Commands OperationThis mode of operation is very similar to the previous mode with the exception that a list of commands which need to be executed can be sent to the robot at once, incurring only a single 21 minute penalty. For example, after examining the image it may be determined that the robot need to move forward 10,000 clicks, then turn left 90 degrees, then move forward 15,000 clicks, then turn right 35 degrees at which point it will be in position to acquire the object. By sending all of the commands at once only a single 21 minute penalty is incurred.

Automated OperationIn this mode of operation, the team writes a program which is assumed to reside on the Martian Observer. It receives inputs directly from the Camera and issues commands directly to the robot without human intervention (thus incurring no 21 minute penalty). These commands will be initiated by a command from Mission Control. One example might be to send a command such as “go to target”, in which the remote program monitors the robot position and sends it successive commands until either it gets the robot to the target or it gives up, then returning control to Mission Control. Thus the Mission Control commands might be “go to target”, “pick up target”, “go to destination”, and “drop target”, thus incurring only 4 21 minute latency penalties. Or a very advanced system might only issue 1 command “do it” in which case the real time component of the actual robot time may make the difference between the fastest time (i.e., there is only 1 21 minute penalty).

In practice, a combination of any and all of these modes is acceptable. This is certainly suggested as a backup if an aggressive design is attempted.

Interaction of the Components of the System:The assumed interaction method of all the constituent parts of the design is network packets over the 802.11 wireless Ethernet network. Blocks for accessing the wireless webcam imagery will be provided for Labview, as well as blocks to provide the positions of the various entities over network packets. The CSE students will learn to write programs to interact with the network in lecture.

Communication between the interacting components of the system will be large part of this project. Basic TCP/IP sockets will be used to communicate between the components of this system. Some communication details follow.

RobotEach robot will be addressable via an assigned IP address and will have two onboard servers running on ports 10001 and 10002. Port 10001 will communicate with the drive motors sever and port 10002 will communicate with the servo motors server. Communication with the robot will be in ASCII encoded strings of characters. Command sets for the driver motors and servo motors will be forthcoming.

Labview Virtual InstrumentsEach group will design aLabview VI that are capable of discriminating various objects in an image and providing feed back about their location. You will also be able to set up a block on the sheet that will create a network server that can send information to a client that connects to it. The network interface with the Labview VI and the format of the data that it returns over the network will be designed entirely at your discretion. For Instance, your group may choose to reply to a client request with one string of data consisting of all vital pieces of data. Alternatively, you may set your Labview VI in such a way as you ask for data about a particular object such as the orange ball or the target.

Network Communcation LibraryThe basis for all system communication in this project will be TCP/IP sockets. Command Central of the project should be implemented in NetBeans and use standard Java Socket API that is part of the java.net library. Documentation for these classes is available here: http://java.sun.com/docs/books/tutorial/networking/sockets/

The IP address of your robot and the IP address of the machine where the VAB code will be running will be provided at a later date.

Acquiring the ObjectThe robot must be able to acquire the target (ping-pong ball) so that it can be transported to the destination (target platform). You may use any of the provided materials or any purchased materials (assuming they have been approved by the faculty members or Necdet Yildirimer) to devise a method of acquiring the ball. Since you will be in Mission Control, you must devise a way of assuring that the robot can align properly with the ball for acquisition. The ball must be acquired in a secure manner so that it arrives at the target with the robot.