Preliminary Proposal for ResearchVehicle Design for Remote-Terrain and Rock-Crawling Application:To satisfy Clarkson University credit requirements for ME445 Integrated Design and HP490 Honors ThesisJoshua T. HarwoodOctober, 2005Abstract: For decades there has been a desire and a need for vehicles that can perform in remoteareas with exceptionally rough terrain. This desire and need has come from many areas,including exploration of remote regions such as the ocean-bottom, militaryreconnaissance and personnel transportation, exploration of other planets, personaltransportation vehicles in regions with extreme weather or climactic conditions, remotelyoperated vehicles used in places unsafe for human presence such as bomb-threatenedareas, and more recently, for recreation and competition purposes associated with rock-crawling and off-road challenges. This study will have two parts, the first to satisfy theClarkson University ME445/446 Integrated Design requirements, and the second part anextension of that work to meet the HP490 Honors Thesis requirement. The first part ofthe study will research, design, and build a prototype vehicle that employs the maindesign features and concepts discussed below. This prototype will act as a physical“proof of concept” model. The second part of the study will expand on the concepts andfindings of the first part to design a full scale personal transportation vehicle for use inrock-crawling and off-road application. This will be an extension of the first part in thatit will integrate the geometric and physical concepts with the power and control systemsthat would differ on a full-scale vehicle from those of a small-scale prototype. Thesesystems will include a hydraulic steering control system and an internal-combustion drivetrain system. To meet the thesis requirements, the design feature of most interestthroughout this study will be an articulated-frame, center-pivoted steering design.Similar designs are currently in use in other vehicles, and modeling studies have beenperformed on this type of system. However, these vehicles have been designed to travelprimarily in the horizontal plane and the models used assume simple in-plane motion andneglect suspension effects. As applied to rock-crawling or extreme off-roading, theseassumptions cannot be made due to the inherent multi-plane terrain over which thevehicles must travel and the significant suspension-related movements perpendicular tothe direction of travel. This study will attempt to extend previous articulated-steeringmodeling into the third dimension and to find if the benefits of using such a systemremain valid under these conditions.Problem: Vehicles that operate primarily in remote areas through extreme rough terrain must bespecially designed to withstand loads and stresses outside of the normal operatingconditions of standard vehicles. Extreme flex and articulation of steering and suspensionsystems is inherent when vehicles must navigate over and around obstacles of significantsize or sudden and abrupt changes in the geometry of the driving surface. These extremeconditions cause significantly more fatigue and wear to components than normal drivingconditions and result in breakages or the need for frequent, costly replacements. It is also imperative when navigating in these terrains that traction is maintained at alltimes and control of the vehicle is maximized. In some circumstances, it is important thatthe vehicle is capable of maneuvering through a certain area with little or no disturbanceor damage to the environment or driving surface on which it is operating. These needsoften conflict with one another, as the large, aggressively-treaded tires that are often usedfor off-road vehicles can very easily cause a great deal of disturbance to the ground.Another existing problem is tire placement. When maneuvering a vehicle over an objectit is important to issues of clearance and balance (or stability) that the tires of the vehiclemaintain a certain path or placement on an obstacle. The configuration of traditionalsteering systems results in the rear tires following in a different track than the front tireswhen the vehicle is turning. This means that an operator can steer the front tires along anecessary path on an obstacle, but if the vehicle is not following a straight path, as isoften the case, the rear tires will take a different position on the obstacle. This effect canbe very detrimental to vehicle performance and safety.Many vehicle designs have been used for the applications mentioned, however due to the remaining problems that arise, there is a need for a vehicle design that minimizes or eliminates these effects.Problem Background: The first part of this study will investigate existing steering designs, specificallyarticulated-frame steering designs, and analyze the performance of these designs withrespect mainly to the aforementioned existing problems. Both small-scale, remotelyoperated vehicles, as well as large-scale equipment will be analyzed. Articulated steeringvehicles can currently be seen in many areas:- NASA has used many such vehicles for exploration missions on the moon (bothmanned and unmanned) and Mars.- Police and security departments have used such vehicles and robots for unmannedinspection of bomb-threatened areas or to look for people in building rubble.- The military sends vehicles into areas unsafe to send troops to gather intelligence.- Large construction and earth-moving equipment, as well as log skidders, employthe articulated steering feature- Farm tractors and public transit buses are beginning to be marketed with anarticulated steering optionThe second part of this study will involve the design of a full-scale rock-crawling vehicle.Rock-crawling has been, until recently, mainly a recreational activity for those who couldafford to build their own specialized vehicle or to modify their stock vehicle sufficientlyenough to perform the task. However in recent years, rock-crawling has quickly becomea competitive activity and has very much turned into a lucrative commercial market. - Dozens of annual off-road and rock-crawling competitions are held around thecountry, drawing spectators and competitors from hundreds and