2016 Evolocity High Schools competition Technical regulations

Transcription

1 2016 Evolocity High Schools competition Technical regulations (Amended gratefully from Greenpower F24 regulations, UK) MULTI (3 + )WHEELED VEHICLES All vehicles are subject to scrutineering and compete at the scrutineer s discretion. For any technical queries please post questions in General Discussion on evolocityschools.freeforums.net/ and wait for Admin to answer. Explanatory notes in italic. Chassis and general construction: 1.1 Chassis of robust build with suitable materials and joining techniques. 1.2 Locking nuts should be used at all times on safety critical components, but it is vital that at least one full thread protrudes beyond the locking part of the nut. Other mechanisms such as pin locking (e.g. castellated nuts) for sensitive components will be accepted at Scrutineers discretion. 1.3 A solid bulkhead forward of the drivers feet. To prevent feet escaping. 1.4 Provide flat surfaces for mounting three race numbers (approx. 200mm x 150mm ea.) and sponsor decals to be seen clearly at all times from front and profile view. Note to teachers/mentors: Good design and good workshop practice should be used to alert students to possible failure points in a system and how such issues might be mitigated. Consideration of how the nature of material selection, and the design itself will affect strength, stress and fatigue factors could also be brought to student s attention, in addition to simple restraints and the like. Primary disciplines: Physics (loads, forces, design), Materials (adequacy, type e.g. Metallurgy), Workshop practice (cutting, drilling, welding, tool handling, gauging appropriate materials and placement). Centre of Gravity 2.1 In the event of a vehicle being deemed unstable by the scrutineers, or overturning at any time, it may be restricted from competing in any or all events at the discretion of the scrutineers. See tips below. Roll bar: 3.1 The vehicle must have front and rear roll bar offering protection in accordance with the diagram shown here the helmeted head of all drivers must be at least 50mm below the line A-B as shown. 3.2 Roll bars must be firmly secured to the chassis of the vehicle using mechanical fixings. Gluing/bonding of roll bars to chassis with no mechanical fixings is not solely permitted. At least one triangulated brace must be fitted to the rear roll bar. This brace should attach to the chassis of the vehicle at one end, to not more than 200mm from the top of the roll bar at the other, and must be capable of taking forward and rearward loadings. 3.3 Aluminium or steel roll bars are to be used and must be strong enough and of sufficient dimensions to perform satisfactorily. If in doubt check material suitability with Evolocity. Students should be encouraged to see the fundamental physics involved and how a high centre of gravity can make a vehicle unstable, particularly when cornering, and how it may contribute to handling difficulties. Primary disciplines: Physics (loads, forces, design), Roll cage should be strong enough to support the weight of the vehicle and driver when rolled over. Primary disciplines: Physics (loads, forces, design)

2 Explanatory design note: Develop a roll cage in such a way as to provide an effective safety cell for the driver that is able to withstand reasonable impact forces from all directions. The diagram below shows an example of where directional forces have been considered. Seat belt (Optional): A minimum 4 fixing point, 50mm width safety harness with secure fixing points on the roll bar or chassis. Harness shoulder strap fixing points should be close to shoulder height and neck width (approx. 150mm) While this section is optional, and it mandates a four point harness, we would encourage teams to consider a 3 point harness as a minimum (e.g. from a car) Explanatory design note: In considering the frame protection (roll bar) and seat belt, designers should take the view that in the event of any impact from any direction and/or the vehicle overturning the occupant is enclosed in a 'safety cell' and protected from harm as much as possible. Restraining the occupant from inadvertently escaping from the vehicle in such a situation is considered good practice. Chain guard: The drive train must be adequately guarded to prevent fingers, hair and clothing becoming trapped at any time by either the occupant of a vehicle or any person working on a vehicle during the course of any event. Tyres and steering: 6.1 Tyres not excessively worn (no canvas showing) 6.2 Steering systems must have minimal play in joints Lateral triangulation In this section we encourage students to consider safety aspects of design and construction. Think of 'what if' and how the possibly harmful result of any accident or incident may be mitigated or eliminated. Advanced students may want to consider active collision avoidance and stability control as contributory safety systems. Primary disciplines: Physics (loads, forces, design), Materials (adequacy, type e.g. Metallurgy), Workshop practice (cutting, drilling, welding, tool handling, gauging appropriate materials and placement). Human factors as well as design play an important role in construction and maintenance safety. Having students complete a checklist before beginning to work on specific parts of a vehicle is one way of assisting, and encouraging students to think about ways to avoid potential future issues eg having two people check and confirm that the battery is disconnected before anybody approaches any part of the drivetrain. Likewise having a second person review any work that has been completed before a repair or construct is tested. The review may simply be a check that guards are firmly in place and split pins etc. properly fixed, this is one way of possibly mitigating issues with human frailty (forgetfulness/overlooking the obvious etc.) and is often used in industry today. Workshop practice (cutting, drilling, welding, tool handling, gauging appropriate materials and place-

3 Primary disciplines: Design, Workshop practice (construction and assessment of systems). Braking: 7.1 The vehicle must have an effective braking system that will prevent it from being pushed from standstill with the brakes applied. 7.2 The driver must be able to operate the brakes without removing either hand from the steering mechanism. Driver and seating: 8.1 The vehicle will have one seat firmly fixed to the chassis & the driver will remain in this seat while racing. In designing and completing a braking system some thought should be given to lateral stability and effectiveness, as well as weight distribution. Brakes must also stop a vehicle in a reasonably straight line from speed, and should be effective in terms of wheel loading (i.e. If a wheel is lightly loaded it could skid and won't be as effective when brakes are applied). Primary disciplines: Physics (loads, forces, design), Materials (adequacy & type), Workshop practice (material selection, placement and construction), Human Factors. 8.2 The driver must be seated in a conventional feet forward, head to the back position. 8.3 There must be a solid floor under the whole of the driver. 8.4 There should be some form of padded head rest behind the driver s helmet to prevent whiplash. 8.5 Driver/rider to wear cotton overalls, full face helmet (if no visor then goggles to be worn), sturdy shoes and gloves. There is to be no bare skin exposed, long hair tied up. Workshop practice (gauging appropriate materials, placement and fixing). Electrics and batteries: 9.1 Batteries must be adequately secured to the chassis and separated from the driver by a bulkhead and/or enclosed in a way that will prevent any person or object from being able to short circuit battery terminals. Batteries that require it will also need the enclosure to allow adequate ventilation. 9.2 Fused link or appropriate Circuit Breaker in place immediately from the power supply rated at an appropriate level for the system in use. It must be sufficiently sensitive as to provide fast-acting protection for wiring or component failure. 9.3 A battery isolation switch must be fitted. It should be clearly visible, easily accessible to the driver and from out-

4 side the vehicle. On/Off positions must be clearly marked. The switch must be appropriate for the current used. Example can be found at High-Quality-500A-Battery-Isolation-Switch/p/SF2245 or even cheaper on Trade Me by searching for Battery Isolator Switch. The battery isolating switch used on speedboats are also suitable. 9.4 The motor controller must be adequate for the task, constructed and mounted in a workmanlike manner. For vehicles competing in the Standard class, the controller must not be a 'boost' type controller. It must be based on 0-5V d.c. microcontroller to be used to encourage programming skills. 9.5 Vehicles competing in the Standard class are required to use the batteries, motor and gearbox listed in the class appendix attached to this document. 9.6 Vehicles competing in the Open class section are required to have motors that develop no more than 1kw in power. Battery voltage is not permitted to exceed 48v. 9.7 All components that require it must be provided with adequate heat dissipation. This may include active or passive systems, particular note will be taken by the Scrutineers to ensure that should any component fail there are adequate safeguards in place to reduce the likelihood of fire or other catastrophic event. 9.8 The throttle must reliably return to zero when it is released. 9.9 All wires and terminals on the vehicle must be neatly run, secured and unable to chafe, away from moving parts, and be rated correctly. Other: Primary disciplines: Design, Physics (electronics, ohms law etc.), Materials (adequacy), Workshop practice (tool handling, gauging appropriate materials and placement) All bearings smooth and free running 10.2 All cockpit edges and sharp edges/protrusions in the cockpit must be padded/protected. Evolocity can supply a Health and Safety Plan, RAMS is the responsibility of the school. Workshop practice (gauging appropriate materials and placement, assessment of systems). Build Tips: When designing your vehicle think about how you will store and transport it. Larger vehicles will be potentially more difficult to manage.

5 Keep the Centre of Gravity low to improve stability. For example on multi wheeled vehicles keep the driver as low as possible with respect to the chassis. One way of achieving this is to make the seat height below wheel hub centres. Batteries typically have high mass, so keeping them as low as possible will also assist. OPEN CLASS If schools build a vehicle that utilises another form of motor, battery and/or controller they are eligible to compete (at the scrutineer s discretion) in the Open class events (Indicated on the Competition Category Document) providing: (i) Multi- wheeled vehicles operate between 301W and 1kW (ii) Any other modifications need to be presented on the online forum to determine if they are suitable for the Open class (in terms of safety)