1. A Portable One-manned HoverBoardTechnical Design 2 Presentation14 Apr, 2012

2. Contents Propulsion System Steering System Display Braking System Noise Control Tasks Assignments Timeline for Semester 6 Plans for Semester 7 Budget for Semester 6 3. Abstract People are rendered into the state of confinement as theytravel. This has led to the mentality of helplessness in emotion andspirit for these users. A HoverBoard is therefore proposed as it can move freely andefficiently at an appropriate level above ground over various terrainswithout the constraints faced by the normal road bound vehicles. With such a vehicular transportation system, a flexible travel plancan be realized and the user experience can be enhanced in terms ofspiritual and emotional satisfaction. 4. Achievements during Last Semester Construction of real-size prototypes Experimentations regarding to air pressure Experimentations regarding to stability Programming of the microcontroller Analytic user interface Realization of hovering function 5. Propulsion System 6. Propulsion - Concept Propeller - LEDFDPS90-1A19 Ducted fan, 1900kW, 22.2V, 70A Electrical Speed Controller - Pentium-100A 5.25V/6V output 7. Propulsion - Concept 8. Propulsion Embedded control Avoid loading the Battery Elimination Circuit Coherent with other modules in system Accurate signal modification 9. Propulsion Embedded control Control signal PWM Amplitude5.25V or 6V Amplitude 5.0V Frequency 50Hz Frequency 50Hz Duty Cycle 1ms 2ms Duty Cycle 0.5ms 2ms 10. Propulsion Embedded control PWM generation PWM waveform 11. Propulsion Embedded control Voltage level shifting Level Converter Analog signal input - Potentiometer 12. Propulsion - Experiment Assembled electronic componentsTwo control channelsMicrocontrollerOutput signal Dual-channel control 13. Propulsion - Experiment Experiment setupControl signal PropellerTesting standWeighing machine Iron net 14. Propulsion - ExperimentThrust vs Duty Cycle 35.0 30.0 25.0 20.0Thrust (N) 15.0 10.05.00.0 -5.0 0 0.51 1.52 2.5 Duty Cycle (ms)Graph of Thrust vs Duty Cycle 15. Steering System The HoverBoard, unlike in conventional vehicles, do not have wheelsin contact with the ground to provide the required force for steering. The steering system, designed for the HoverBoard, should not havemore burden than the that of the wheels. The designed steering system should not affect the operation of anyother system in the HoverBoard. 16. Design Alternatives1. Using steering rudder or vanes placed at the back of the propulsion systemPrinciple: Changing the orientation of the rudders to steer the vehicle2. Two propulsion fans to provide the turning torquePrinciple: Changing the RPM of each propulsion fan to create a torque around the center of gravity of the HoverBoard. 17. Selection of Optimal Design With two rudders at the back: Advantage: Physically easy to construct Disadvantage: High degree of inefficiency, high powerrequirement for the high waste, heavy, large space occupied, With two propeller fans: Advantage: Small enough, easy to control, growth of power ofthe propulsion system, easy to mount, light, competitivelyefficiency Disadvantage: Still require a large amount of power. However, compared to the rudders, the advantages prevail. 18. Testing platforms Platform for propulsion experimentProtection net: two layers protection. Outside layer is ironwhile inside one is standard steelWeighing machine: to measure the propulsion forcePropulsion Fan: operate to provide the propulsion forceTriangle support: to fix the fan and to keep the fan fromTouching the machine Platform for steering experimentTurntable: a bearing is mountedbetween the two wooden plates tomake the upper one moveableSpring: to measure the steering forcewhen the two fans operate 19. Propulsion experiment Duty cycle ReadingThrust (ms) (Kg)(N) Thrust vs Duty cycle0.5 1.60 35 11.60 301.21.8862.86 251.32.2786.78 20Thrust (N)1.42.62 10.2 151.53.055 14.55 101.63.628 20.281.73.98 23.8 51.84.39 27.9 00.5 1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 21.94.48 28.8Duty cycle (ms)2.04.58 29.8THRUST = (READING 1.6) * 9.81 20. Steering experiment Current data Future work:S.NROUGHLYSPRING To do more experiment about measuring FORCE (N) the steering force by using the sensor and meter1.402.30 To do some experiment about testing the angle of the spring in order to calculate3.32 the steering force 21. Braking System Braking, for the purposes of the HoverBoard, is defined asbringing the HoverBoard from a state of motion to rest(velocity = 0) while it is hovering. 22. Need for Braking The HoverBoard experiences very little friction, which makes a goodbraking system essential. For portability, the braking system should be realized with as littleadditional weight and power requirements as possible. In order not to compromise the hovering capability of the HoverBoard,any form of braking introduced should not make use of contact with theground or any external body. 23. Design Alternatives The various options considered for braking of the hovercraft were: Thrust reversers Turning off leaf blower Turning around 180 degrees and accelerating Reducing power of leaf blower Two more fans in reverse direction for braking (negativepitch) 24. Thrust Reversers 25. Thrust Reversers A hollow cone of metal/plastic is mounted on the HoverBoardbehind the thrust fans. This blocks the airflow from the fans and redirects it in the forwarddirection, thus utilizing the thrust of the fans for braking. Do not require extra fans to create the needed braking force. Dontrequire the leaf blower to stop. Do not require any physical turning. 26. Thrust reversers in airplanes Thrust reversers are used in some airplanes during landing to reducethe speed of the plane after it has touched down on the landing strip. The thrust reversers use the air flow through the engines to createbraking thrust, thus slowing down the plane. 27. Proposed experiment Fans ThrustSpringReversersSpringBalanceBalanceHoverBoard 28. Proposed Experiment Fans Thrust Spring Reversers Spring BalanceBalance HoverBoard A rectangular testing board on which the fans and thrust reversers aremounted. The setup is placed in a basin with ball bearings - to reduce frictionbetween the board and the floor. Both ends are connected to spring balances. 29. Proposed Experiment FansThrust SpringReversers Spring Balance Balance HoverBoard Measuring the thrust in forward direction (removing the reversers). Measuring the braking thrust (with the reversers in place). 30. Noise Control The current design of the HoverBoard consists of two blowers andtwo propeller fans, of up to 42,000 RPM. All of these major components produce a considerably high level ofnoise. Continued exposure to such noise is detrimental to both the usersexperience and health. 31. Background to Noise Control In the field of study of noise control, noise is quantified using afrequency spectrum and commonly classified into two followingcomponents. Noise Frequency Spectrum Tonal noise, consisting of Blade Passing Frequency (BPF) and itsharmonics, is frequencies with power peaks. Broad band noise refers to the remaining frequencies which spanthe entirety of the spectrum. 32. Background to Noise Control Tonal noise is produced by periodic forces acting on the airthat passes through the fan. An elemental area of air near the blades is exerted by a forceevery time a blade element and its associated pressure fieldpasses through it. Broad band noise, in contrast, is caused by random,fluctuating forces. It is mainly caused by the turbulent boundary layer andvorticity shedding. Noise control techniques vary depending on the type of noisein question. 33. Noise Control Techniques Noise control techniques can be classified into two categories: Passive noise control refers to techniques that do not requireconstant monitoring and feedback. Example - Dampers Active noise control refers to control techniques which constantlymonitor the external parameters and respond based on thefeedback. Example Sensors 34. Passive Noise Control Technique #1: Include a bellmouth at the inlet of the propeller fan (primarily broad band noise) Technique #2: Include an extra long duct either at the inlet, outlet or both (both broad band noise and tonal noise) Technique #3: Wrap a damping layer around the duct or bodyof the fan (both broad band noise and tonalnoise) 35. Passive Noise Control Technique #4: Optimize positioning of fan so that no obstaclesobstruct the fan or hinder the efficiency of thefan (primarily broad band noise). Technique #5: Optimize usage of the fan RPM, as the smallerthe RPM the lesser the noise. The propulsionand braking system should be designed withoutwaste of RPM (both broad band noise and tonalnoise). Technique #6: Line the inside of the duct with acousticabsorbents (both broad band noise and tonalnoise) 36. Active Noise Control (ANC) Basic Structure of ANC system ANC is an electronic circuit which includes1. A sensor (microphone)2. An actuator (speaker) and3. A controller (Digital signal processor or Microcontroller) ANC produces the anti-noise to eliminate the noise bydestructive interference. 37. Proposed Experiments During the next semester, the passive noise control techniqueswill be experimented first To investigate their effects on noise and To collect data on reduction of noise levels. Active Noise Control will be implemented if we can obtainguidance from this area of expertise and also dependent onthe outcome of the experiments on passive noise control. 38. Tasks Assignments Abishek: Braking system Shuwen:Display (as part of User Interface) Soe: Noise control Yinan: Propulsion system, WiFi Zhaohe:Propulsion system, steering system 39. Timeline for Semester 6 40. Plans for Semester 7 Plan 1: Implement the WiFi Feature The WiFi feature planned for Semester 6 was not completed. Therefore, it will be carried on to the Semester 7. Plan 2: Conduct Experiments on Steering The test platform has been assembled. Experiments will continue in Semester 7. Plan 3: Implement a User Interface A Demo program has been created during Semester 6. With this understanding, the required program will be developed in Semester 7. Plan 4: Conduct the Proposed Braking and Noise Control Experiments This semester focused on research. Experiments subsequent to this research will be done when we come back from SEP. 41. Budget for Semester 6 42. End of PresentationThank you for your attention.