Weston Middle School
Technology/EngineeringCourse Materials
As it follows a route (line) home, a robotic vehicle will encounter a series of devices that will allow it to pass, load and unload cargo, etc.
Structures such as gates, doors, draw bridges, elevators, and turntables need to be built and programmed to allow for timely passage.
Key concepts for this project include the following:
- Mechanisms
- Basic Programming
- The concept of systems and subsystems
- System integration
In preliminary assignments, each group will complete the following:
- Attach NxT brick to studded base plate
- Attach a motor vertically to base plate
- Attach a motor horizontally to base plate
- Creat a suspension for an axle which supports it at both ends
- Mount a beam vertically to the base plate, with side-bracing from two directions.
Students will be provided with examples of mechanisms that enable mechanical advantage. (A library of videos and photos will also be available.) Before planning the project, partners should choose from at least 2 of these, and build them onto the lego base. This preliminary assignment will establish how to connect motorized mechanisms to the base without relying on axles for structural support.
Once done, students may choose which one will serve as the basis for the design of their final project, and will complete a proposal form to help document their decisions. A quick sketch and/or mockup will help them visualize which mechanism will give the desired motion.
For most projects, mechanisms must be positioned along the edge of the baseplate, which will abut the roadway( about 10-12" in width).
For some devices, such as elevators and other vertical-lift systems, the baseplate may be positioned on a chair or or other platform above the roadway.
In order to prepare for programming, students will need to test the mechanism once it is connected to the NXT. Once it works, a sensor must be added that will “see” the vehicle approaching and cause the appropriate response. Placement of sensors and figuring the ranges should be done with the actual vehicle to insure success.
Finally, students will do a presentation of their work which will be included in a video of the entire system!
Milestones:
1.Project Introduction; Mechanisms;
- Attaching Technics to Studded beams- Demos
- Get base plates and label with group names
- Securely attach NxT brick to base- How do we do it?
- Attach NxT motors to base in 2 different ways;
- Building a suspension;
- Side-brace a vertical-mounted beam
- Try out 1 mechanism, maybe 2- worm gear, pulley, etc
3. Construction Work/programming
- How do we make the gate strong yet light in weight- a frame with foil?- Relate to DesCon7- Trusses/Efficiency
- How do we make stable structures? Relate to DesCon7
- How will it move?
- How will it 'see' the car?
- Program must:
- Detect the vehicle
- Raise gate or mechanism(and sound horn)
- Allow vehicle time to pass( or detect when vehicle has passed)
- Lower gate
- Be ready for next vehicle
- Contain full standard documentation
4.Final construction; artistic constructions
5.Presentations and demonstration
6. Take Apart and Sort
Sample projects:
Tunnel: When car goes approaches tunnel, a gate opens, lights and warning sounds go on in the tunnel, and go off at the end when vehicle leaves.
Missile Launcher: When car delivers missile to launcher, launcher throws it across room( lever)
Drawbridge: Drawbridge opens when "boat" approaches, sounds horn, puts down barrier; when boat passes, lowers bridge, lifts barrier, sounds horn( worm gear)
Turntable: When vehicle drives onto turntable, control system rotates vehicle and puts it onto another road.
Loader: When car stops, loader drops cargo into hopper; sounds alert when done (Lever)
Advanced loader: Loader drops measured amount of poker chips or marbles into truck; signals truck to drive off (crank or screw).
Elevator garage: When vehicle enters loading platform, platforms raises vehicle up to storage level(pulley, worm gear)
Crane: When car stops, crane lowers velcro "magnet", which picks up load and drops it elsewhere.
Tollgate: When car approaches tollgate, "driver" drops toll in slot which opens gate; car then proceeds through( worm gear)
Vehicle-based options:
Car Carrier: Car drives onto car carrier, which then drives car to delivery point; car then drives off ( vehicle)
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