Presentation 3

11/16-11/30

For the last two weeks, we've been working on getting together the BOM for all parts that will need to be purchased for the Spring semester, working on the 3rd presentation, and working on the rough draft of the final report that is due at the end of this week. There are still some details that need to be worked out. Engineering drawings for all of the parts that are going into the bogie need to be made for the final report and for manufacturing that will occur next semester. Michael has started working on these, however, it will take some time because there are so many different parts going into the bogie design. The goal for this week is to finish the rough draft of the final report in order to get feedback for the final draft which is due coming up.

11/9-11/16

During this week, we continue our progress in our Bogie, Failsafe and Steering. All subsystems are coming together little by little. In the current CAD design, the propulsion, breaking and suspension sub-systems have been implemented. The design has not been finalize but it will be a preview to visualize the final design. There has been minor changes in our design as we have noticed some issues. For example, the angles of our steering changed slightly thus one of the pulleys changed from 24 teeth to 28 teeth. The linkage controlling the upper steering instilled us to make the change. Also, some gaps in the bogie were changed in order to mount the gear housing system. Also, we began to write the rough draft for our final report. Adding all details of our design and explaining why the changes took place will be of upmost importance to ensure that future teams are able to improve and progress.  Also, we will be finalizing the B.O.M. for our parts. We have yet to turn in the B.O.M as we want to completely finalize our design and obtain a accurate total cost to ensure fundings are delivered as necessary.

11/2-11/9

During this week, our group the main focus to finalize is the housing of the gears, the prototype testing and the implementation of the subsystems. The function housing of the gears is to keep in place the gear system without impeding any functionality of the rest of the subsystems. Essentially, the limited space in-between is the main concern for this design. The rapid prototype is made of wood which will enable us to observe the functionality of our current design. The main functionality of our prototype is to identify exactly the tolerances necessary for the Bogie to stay in place as it goes up and down the slope. The tolerances of the two bottom wheels are of upmost importance as it will prevent the bogie from hitting the top. Testing our current design is necessary to change any details as soon as possible to avoid late major changes in the future. By allowing ourselves a respectable amount of time to finish our design, all unexpected errors can be resolved in a timely manner. Also, in accordance to the groups, the date(November 16) we planned to order parts is approaching thus all the parts necessary for our system will be listed to meet the deadline. The implementation of all subsystems is of upmost importance as all systems will come together in the end. We have been keeping close communication with the other teams as well as sharing all our design CAD files to ensure that their design will fit accordingly.

10/26-11/2

This week was spent working on the second round of presentations. In order to prepare for this, FEA was completed on the failsafe. In order to do so, hand calculations were completed to determine the impact forces that would occur during a failure. The FEA von mises stresses can be seen in figure 1. Gearing for the steering was also determined this week.

The second presentation is as follows.

10/19-10/26

During this week, our team continue working on the new adjustments towards our bogie, steering and failsafe. A meeting via Skype with Bengt was made in order to discuss our adjustments and new possibilities to improve our design. It was decided that the bar connecting both bogies will be lowered below the track. By lowering such bar, the normal forces will be greatly increased thus the amount of torque necessary by the motor to go up the 17 degree incline will decrease considerably. Another advantage of lowering the bar is the spacing within the bogie will increase. The more space we can provide for the other sub-teams the better it will be as they will not be limited to certain parts and design. The steering was decided to be maintained as a gear and pulley system which will provide more safety thanks to the gear ratios in place. Our communication with other teams is and will continue to be essential as we want to make sure all sub-systems can fit as expected. Also, we had another meeting with all the sub-teams where we decided on a date where we will finalize our design and all the parts that will be order. November 16 is the day every sub-team will submit their list and prices of all parts needed to essentially obtain the funding and finally placing the order. By setting the date we will ensure the parts will come before the beginning of next semester.

10/12-10/19

This week we met with Bengt to discuss the design progress we currently are making. Propulsion has made a final decision on the motor that they will be using. The placement of their components are making a huge impact on where we can place the linkages for the steering. We have a final concept for how the steering will be switched with one single actuator located at the top. It will use a driver diad for the top steering arm, and a geared pulley system for the lower control arm. We are also discussing using a solenoid as a failsafe for steering and we have a final concept for the failsafe that prevents the cabin from falling through the rails. This would also lower the stall torque requirements for the driving stepper motor. This weekend we are planning on laser cutting out a plywood prototype to see how it fit on the rails. We will also be preparing our presentation for next weekend, and working on the CAD for the linkages.

10/5-10/12

During this week, all sub-teams composing the half scale project decided to have a team meeting. In this meeting we essentially discussed and set a deadline for different issues. In accordance we shared our future plans and our future design changes. The changes and all design components are dependent of each other, therefore knowing exactly the route everyone is taking will ultimately make our work easier. The team decided in a deadline to acquire all the information and decide in what parts will be order. By doing so, we give ourselves plenty of time to test and prototype our systems. Our communication with one another is crucial as it will define our success in the project. In our specific team, we decided to assign tasks, thus it will be easier to accomplish our final design. We decided to change our steering system from a 2 motor controlled system to a 1 motor controlled in conjunction with a pulley system. By changing our steering design to only one motor, the chances of failure will be decreased and there is more change for two motors to fail in comparison to one motor. Essentially one member of our group will focus on designing the new steering pulley system, while he other person will continue the changes in the CAD design we currently possess. One important and crucial matter we came to accordance with the other sub-teams is to have weekly meetings thus improving our communication.

9/28-10/5

This week we had a meeting with Bengt, the patient holder for the railway and bogie design. We showed him our initial designs, and he gave us really good feedback on improvements and things to consider. One of the suggestions completely changes our direction for design, however, will be better in the long run. He suggested that there only be one actuator for steering of each bogie. If two actuators were used for each bogie, and one of them fails, that could mean that both bogies could be derailed. We are planning on using a timing belt system to actuate the lower steering arm. The next has to do with wind forces on the bogie. Up to this point, I designed the joint between bogie, without considering a moment being created by the cabin from wind forces or lateral forces during cornering. The universal joint will have its width stretched in order to overcome these forces during windy conditions or cornering. The placement of the joint is also important and current is not in plane with the axial of the main hub wheel. The problem will be creating something that still allows the axial to be driven the way that propulsion is suggesting. Bengt also suggested that we redesign the upper steering arm from a four bar mechanism to a simpler rocker. This is one design point, that I am reluctant to change. It is possible to design the driver diad to lock out and resist more force than just the holding torque of the stepper motor. Overall the group needs to meet today, and split the work load, and have create clear guidelines and design requirements after meeting with Bengt.

9/21-9/28

During this week, we continued working on our design and calculations of the steering and the sizing of some bolts considering the specifications given by previous semesters. Our group also focused on arranging together a presentation which will take place during this week. The presentation will emphasize the progress and the future scope to complete our design. In this week, recollecting data and and understanding how we wanted to presented towards the audience was critical in order for the rest of the sub-teams to understand the route we will be taking and how exactly it will influence each component being designed by them. The kinematic calculations for the steering were typed in order to avoid any confusion and also to avoid any mistakes when other teams revise the steps followed. After the kinematics, the force calculations will be next as we finalize the specifications and final designs to our project. Constructive criticism is always welcomed from any of our peers as it may lead to realize mistakes or it may also give root to new ideas. Also, some changes were made to the bogie 3D model with our new ideas considering the fails experienced by previous teams. The discussions on the new ideas we planned to implement in our design were implemented to show preliminary view to our way of thinking and what ultimately will become the new system. Below, pictures of the calculations and the design at this moment in the semester.

9/14 - 9/21

This was the first week that the group split up design tasks. The main portions that need to be worked out are the joint for the bar that the suspension and propulsion connect to, and the linkages for steering. These two tasks were split between group members to work on solo, and to come together the following week to access progress. The calculations for the position analysis of the linkages is needed in order to size the motors that will be used to actuate the steering mechanism. The calculation are planned to be done in excel as to be fluid to change. A big unknown is location of the actuators. As of right now it is difficult to say where the will fit. Placement of the motors will make a huge impact on the design, and so we are currently trying to get a solid design of the bogie structure with placement of wheels, and cross members so that we know what we are working with in terms of placement. The upright structures are being redesign in order to place another wheel below the rails. This new design hopes to eliminate the issue of binding that the bogie experienced last year. Slight changes in wheel positions will also help. This week we plan on working together to develop the characteristic equation to describe the position, motion, and forces acting on the steering system. We also will continue working on the bogie structure. Preliminary hand calculations have been done to size the the joint according to the payload weight. The calculations indicated that a 0.25" diameter bolt will sufficient hold the load of 800 LB we spec'ed, however we are planning on using one somewhat large to take in account impulse force and fatigue that could occur and cause failure.

Week 2

During this week, our main objective was to acquired as much data as possible and identify the issues with their respective solution. We begin by reading the previous summer team report to identify more accurately on what the main problems were present. During our research, we identify that the bogie did not fully functioned during previous test. We identify that the main problem was the constriction of the bogie. It is constrained in such matter that it does not fully travel across the track successfully. In our preliminary attempt to begin working in the project at hand, we begin by brainstorming and ultimately sketching as many ideas as possible which will be helpful in the design of our system. We also deduced that in order for our project to be successful, our sub-team requires to be in full contact with the rest of the sub-teams thus a fully Google Docs folder was created which will contain all the documents related to our project. Although all sub-teams may be working on different parts, our contribution will come together in the end, therefore full communication is of upmost importance. We began by introducing one another and exchanging information to fully create an environment of great communication and team work. Our project team is fully communicating in the lab as well as outside of school grounds. Our main objective for this upcoming week will be to further discuss our next course of action, fully understand the changes and design choices, keep communicating with our fellow team mates and ultimately begin the design analysis.

Week 1 Team Post

• Team members, with brief listing of pertinent skills
• Michael Kemp
• CAD Design, Assembly manipulation, machining (milling/lathe/waterjet), welding, integration, etc.
• Martin Chavez
• 3D printing, CAD

• Jorge Soto
• CAD Design, Assembly, Machining(beginner)

• Team members contact information
• Michael Kemp
• Telephone: (559) 577- 5365
• Email: Michael.Kemp@SJSU.edu

• Jorge Soto
• Telephone: (209) 292-1113
• Email: jorgeLsoto7@gmail.com

• Martin Chavez
• Cell: (510) 684-4809
• Email: martinchvz@att.net

• Team member responsibilities within the team (who will do what) -may change throughout the semesters
• Michael Kemp
• Manufacturing
• CAD Design and Drawings
• FEA

• Jorge Soto
• Modeling and CAD design
• Assembly
• Manufacturing

• Martin Chavez
• Sketches
• CAD

• Proposal narrative (verbal description of what is proposed to be accomplished, which includes design requirements and deliverables)
• Over all Bogie Changes
• Utilize 4130 steel tubing and sheets rather than A513/A36 in order to reduce weight while maintaining rigidity.
• Simplify design from previous and shorten all possible members to reduce weight and reduce risk of long term beam buckling due to large slenderness ratio.
• Attempt to integrate all subsystems in a manner that minimizes the volume envelope of the bogie design and reduces risk of interference and catching of members  
• Steering
• Shorten wheel mounts
• Use 2 linear actuator in order to shorten the linkages
• Look into removing lowe second failsafe wheels

Failsafe

• One wheel on each side instead of two in order to not overconstrain the system
• during turns
• Between bogies
• Add 2 DOF flexibility between bogies utilizing a drivetrain linkage design

• Sketches or drawings

• Critical Path Schedule using   https://gantter.com/   (Gantt chart website) -copy shareale link / screenshot of gantt chart in team blog.
• Budget (preliminary estimate of the cash and VIK – Value-In-Kind – needed to deliver what is being proposed)   Give an ESTIMATED RANGE for this.

Cost of materials will increase if the material is switched from Structure steel to Chromoly steel. A range from $600 - 1000 for the structure is currently projected, however it is hard to currently determine as new component and configurations have not be determined.