STEMM Report

STEMM Report

Systems Engineering II

Remote Controlled Land Sailor

Introduction:

            The Remote Controlled Land Sailor’s only practical purpose in this day and age is for competitive purposes and as a recreational pastime to hobbyists.  That said, the land sailor has a very specific environment where the model is intended for use, primarily flat surfaces with hard ground and moderate winds.  In terms of functionality, consumers are attracted to specific land sailors based on performance, which includes speed and maneuverability as well as the aesthetics.  With the basic requirements of consumers in mind, the final model land sailor was designed to complete timed courses to demonstrate the maneuverability and speed in the final testing stages.  As of now, the land sailor’s designs are completed, seen in Figure 1.  As described in the Rationale, this model has a “T” shaped frame with one wheel in the front and two in the back.  Steering is controlled by the single front wheel hooked up to a servo.  The servo is part of an electrical system that consists of two other servos that control the sail, a battery, and a four extension receiver.  The frame is made from balsa wood with metal support sidings around the mast placement.  Full descriptions on the parts, as well as materials, supplies, and tools can be seen in the Developmental Work section.  All specifications in terms of the size of the chassis adhere to the International Radio Controlled Surface Sailing Association regulations.

Relation to Systems Engineering:

            Because the concept of land sailing, not to mention sailing in general is not new, this design counts as an innovation.  The current design in itself resembles designs that others have been done by others in the past for their land sailors.  However, the final land sailor model for this group will be unique compared to the other designs that precede it, hopefully allowing the model to complete the final tests successfully in the future. 

            The engineering that tied in with this design the most is structural.  The location of parts as well as the design of crucial parts, such as frame and steering, will determine the outcome of this model’s functionality and ability to complete the specifications.  Additionally, the materials and supplies that make up each part will also affect how the final design functions. 

            When manufacturing the model, building will most nearly ties into prefabrication.  In this method, a single person with knowledge on the building process gathers materials that they cannot produce themselves and assembles them to make the final product.  In this scenario, many of the parts are pre-assembled, such as the wheels, ball bearings, servos, receivers, batteries, and sheet metal.  All the manufacturer has to do is shape the materials and supplies into parts (see Plan of Procedures) and then assemble the parts into a final product as directed.  This could also involve the English system of manufacturing, as the materials that need to be duplicated may not be the same shape or size as the original. This problem with non-interchangeable parts is normal when construction is done by hand.

            Being that this project is to design and build the chassis of a remote controlled land sailor, this project falls into the engineering and electronics categories.  Engineering was an important topic to keep in mind when working on the alternate solutions and the CAD models. As stated before, the placement and composition of each part have major effects on the functionality of the design.   This information was important to keep in mind when choosing the shape of each design, material of each part, and the placement of pre-fabricated parts.  Part placement can be seen in Figure 2.  Additionally, engineering also relates to the types of electronic components chosen.  When choosing servos, one has to think about how much force is needed to do the task the servo has to do.  For example, a servo needed to pull a winch is not the same as a servo needed to swing the boom of a mast or operate the steering of a model going at high speeds.  Just as before, part choice is crucial to achieving the planned functionality of a design.  In terms of electronics, part choice depended on the amount power needed to operate and the amount of force the component needs to exert.  These factors influence the type of battery needed as well as what specialized servos are needed for their specific job.  This can be seen in the wire diagram in Figure 3.

Science Concepts:

            This project’s design was influence by several science concepts in the early design phases.  One of the deciding factors when comparing this design to others in the Rationale section was the mast placement and the effects on mobility.  Being that the mast is such a huge structure, the concept of the center of gravity and balance, the principles of which are accredited to Sir Isaac Newton,  played a part in choosing the design.  Because maneuverability is one of the final tests, turning has to be quick and stable to reduce time loss while the final design runs through a timed course.  To accomplish this, the design must have a relatively spread out frame with the sail location ranging from the middle to front area of the central beam.  A poor example of this can be seen in one of the early designs in Figure 4.  The current design has a wheel span of approximately 27.7 inches in width to 36.6 inches in length is sufficient in holding the mast upright in the testing phases. An orthographic view of the land sailor can be seen in Figure 5.  The ability of the servos to turn the steering also relates to the concepts of torque as stated by Archimedes.  Rather than use standard servos provided by the school, more powerful Futaba S3305 High-Torque Standard Servo with Metal Gears will be used.  Standard servos might not be able to handle the strain of moving at high speeds, and even if they can hold the steering column still, turning would be near impossible, if sloppy. 

Integrated Technology:

            Possibly one of the greatest impacts that technology has had on this design process is the compactness that each individual electric component has.  With the specs of each electronic part provided by the manufacturers, their relative combined weight is miniscule compared to the total design.  This decrease of weight and size will have positive effects on the end performance of the land sailor.  A close up of the battery and receiver can be seen in figure 6.  Additionally, the availability of other designs on the internet has given a wider range of solutions that can be found to compare to the current design.  Learning from mistakes and successes of others can be beneficial in the designing of your own solution.  In other words, a large group of opinions can help designer pick desirable traits and turn away bad ideas.

Mathematical Computations: 

            Not many mathematical principles had to be taken into account during the designing of this project.  However, conversions had to be done between the imperial system to the metric system.  Because the groups went by the class 2 IRCSSA standards, we had to stay within the parameters of .75 meters wide by 1 meter long by 1.5 meters tall.  AutoCAD uses imperial units, so these measurements had to be run through an online length calculator to find an applicable measurement.  In reality, the lengths in meters can be multiplied by 3.28084 (feet per meter) and by 12 (inches per foot) to get the end values.  Since only width and length are relevant to the chassis, the measurements from end to end can be seen in Figure 5. Other than that, simple subtraction and addition were used when matching up parts in the CAD views. 

Conclusion:

            The Remote Controlled Land Sailor is a structural based project that takes concepts from engineering and electrical work in the design.  The final model will be built using primarily the prefabrication method with a small English system of manufacturing addition.  While the electric components and the wheels are factory-made, the frame, steering system, and support system will be constructed from materials and supplies.  The parts will then be joined together to form the final model, a “T” shaped land sailor with a single front wheel servo controlled turning system.  This design will help prevent flipping, while the shape also allows for easy mobility and maneuverability.  The concepts of balance and the center of gravity were used in creating this design element during the initial creation of the model.  Math was useful in measuring my design in the 3D renderings, while technologically the relatively lightweight and small components will not detract the designs overall performance.  In the end, the Remote Controlled Land Sailor in the final form will be able to fulfill all of the listed specifications and function as intended by the designer.