Concept Review Pre-Read P07310: Polaris ESMT

RIT Senior Design I 2/7/2007

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Jason Botterill – ME, Team Lead Richard Cheng – EE

Vaibhav Kothari – ISE Yi Fan Zhang – ME

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Table of Contents Section Page Number Table of Figures 3 Team Members 4 Project Background 4 Project Scope 4 Design Specifications 4 Critical Specifications 4 Major Specifications 5 Mechanical Controls Concept Development and Selection 5 Clutch Subsystem 5 Shift Actuation Subsystem 8 Shift Actuation Concepts 9 Concept 1: One Push-Pull Solenoid 9 Concept 2: Two Pull Solenoids 9 Concept 3: Direct Shift Drum Actuation 10 Concept 4: Semi-Direct Shift Fork Actuation 11 Electrical Control System 13 Electrical Control System Block Diagram 14 Ergonomics Design for Gear Button Controls 15 Gear Button Control Concepts 17 Bill of Materials for Design of the Gear Button Boxes 19 Test Bed Concept Development 20 Test Bed Base 20 Electric Motor 20 Input Shaft 20 Input/Output Gear 21 Mounting Bracket 22 Output Shaft 22 Flywheel 23 Proposed Bill of Materials 23

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Specification Table Appendix A Needs Assessment Appendix B

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Table of Figures Figure Page Number Cover Image: Polaris Outlaw 525 High-Performance ATV Cover Figure 1: Clutch assembly drawing 6 Figure 2: Picture of assembled clutch 6 Figure 3: Picture of semi-assembled clutch 6 Figure 4: Rekluse Motor Sports z-Start Auto Clutch components 7 Figure 5: Concept utilizing push/pull linear solenoid 9 Figure 6: Concept utilizing two pull solenoids 9 Figure 7: External view of shift drum 10 Figure 8: Internal view of shift drum 10 Figure 9: Shift fork 11 Figure 10: Shift drum removed from transmission 11 Figure 11: Model of new shift drum 12 Figure 12: Spur gear stepper motor 13 Figure 13: Control system block diagram 14 Figure 14: Rider’s view on the Outlaw 525 15 Figure 15: Rider’s view of left hand controls 15 Figure 16: Rider’s view of right hand controls 16 Figure 17: Ergonomics concept 1 17 Figure 18: Ergonomics concept 2 18 Figure 19: Test bed concept sketch 20 Figure 20: Input gear sketch 21 Figure 21: Input gear close-up 22 Figure 22: Clutch basket close-up 22

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Team Members:Jason Botterill (ME, Team Lead) – Mechanical Control System Richard Cheng (EE) – Electrical Control System, Sensor Integration Vaibhav Kothari (ISE) – Ergonomics, Manufacturing, and Durability Research Yi Fan Zhang (ME) – Test Bench Engineering Project Background: The Polaris Outlaw 525 ATV is a high performance ATV. It is intended for advanced sport riders who are looking for the best in performance. This is not a work ATV so it does not have four-wheel drive, a winch or towing hitch. The Outlaw 525 is the newest model in the Polaris high-performance line and is the first sport ATV to feature an independent rear suspension. More specifics are provided on the Polaris website at http://www.polarisindustries.com. An electronic shifting manual transmission (ESMT) combines the best features of automatic and manual transmissions to provide for an automated, highly efficient transmission. Manual transmissions are generally lighter and inherently more efficient; automatic transmissions are often desirable due to ease of use. In challenging off-road terrain ease of use is very important. Project Scope: Originally, the project plan was to establish a fully automatic shifting manual transmission. This plan was altered early on as the time and human resources necessary to accomplish such an ambitious goal were not available. The combination of a relatively small engineering team and the need to create a test bench to evaluate concepts led to changing the project end goal. The new project goal is to establish a semi-automatic transmission for the Polaris Outlaw 525 ATV. Instead of full automation, rider input will be necessary to shift between gears. The rider will not need to use the foot lever to shift, however, as the physical shifting will be done electronically. While this falls short of the original goal, many benefits can still be realized from the creation of this system. From a performance standpoint, shifts can potentially be completed faster with greater consistency. Additionally, various safety features can be programmed in by limiting the RPM range in which shifts may be completed. Finally, the only step remaining to full automation would be programming the control unit to recognize when shifts should be made. While that seems like a small step, it is quite complicated and could potentially be the source of another senior design project. Design Specifications:

Critical Specifications:

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• The ESMT shall be safe to use. Aside from having a working system, this is the concern identified as most important by our sponsor. This means that the ATV should never do something completely unexpected by the rider.

• The system shall utilize push-buttons (or similar activation device) to control the shifting of the transmission. This semi-automatic system will serve as a proof of concept for the fully automated version.

Major Specifications: • System weight should be less than 7 lbs. One major complaint about the ATV that preceded this model is that it was too

heavy. The new model is about 30 lbs. lighter, and ideally this system would not put much of that weight back on. For a vehicle that weighs under 400 lbs. 7lbs. is much more significant than it would be on a larger vehicle.

• Clutch use shall not be required to use the system. Aside from gear selection, the shifting system shall require no other user inputs. While there are many potential solutions to this requirement, it is necessary to prove that rider inputs can effectively be eliminated from the shifting process.

• Reverse lockout should be retained or engineered. Currently, the reverse lockout system requires that the clutch be disengaged and a button be depressed before the ATV will shift into reverse. This system either needs to be retained, or a suitable system needs to be integrated into the design solution. This is to ensure that in aggressive riding situations it is not possible to accidentally shift into reverse.

A complete list of specifications is found in Appendix A. Mechanical Controls Concept Development and Selection: Clutch Subsystem:

From the outset of the project, the major design choice regarding the clutch has been whether to automate the control or to create a system which does not require clutch actuation. Because of the design of the hydraulic clutch system, very few access points exist to actuate the clutch without disabling the manual lever.

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Figure 1: Clutch assembly drawing

When the clutch lever is pulled, the clutch slave cylinder pushes against the clutch rod (3). The clutch rod pushes against the pressure piece (1) which pushes against the pressure plate (9). This relieves pressure on the clutch disks (5, 6, 7) which are located between the pressure plate and the clutch hub (8).

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Figure 2: Picture of assembled clutch. Figure 3: Picture of semi-assembled clutch. In figure 2, the part indicated is the pressure plate. In figure 3, the indicated part is the pressure piece which pushes against the pressure plate. Because of the lack of access points to the clutch actuation system, it was decided to take an alternate approach to the problem. The design shall not require the use of the clutch. While this is simple from the shifting standpoint, as aggressive shifting does not require clutch actuation, it is more difficult when starting from a dead stop. At the sponsor’s suggestion, the team has decided to solve this problem with the use of an aftermarket part. The part being used is a z-Start Auto Clutch from Rekluse Motor Sports. The following exerpt is taken from their website, www.rekluse.com.

The z-Start Pro Clutch is a centrifugal clutch that uses ball bearings to engage the clutch. The clutch provides a pressure plate with ball ramps. At idle the balls are at the bottom of the ramps and the pressure plate is disengaged. As the rider increases RPM, the balls move out the ramps, push on the Rekluse top plate and force the pressure plate into the clutch pack engaging the clutch. As RPM’s build, the balls continue to move out fully engaging the clutch. When engine RPM’s are reduced the balls drop back down the ramps and the clutch disengages. The take-off is smooth as if you had perfectly feathered the clutch every time. The disengagement is quick eliminating stalls.

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Figure 4: Rekluse Motor Sports z-Start Auto Clutch components.

This system will retain full manual operation of the clutch while eliminating the need for the clutch to be actuated manually for accelerating from a stop.

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Shift Actuation Subsystem: The shift actuation subsystem is the mechanical device(s) that physically shift the gears in the transmission. In generating concepts, many different mechanisms were introduced as possibilities. • Linear solenoids • Rotary solenoids • Stepper motors • Pneumatics • Hydraulics At this point, each of the mechanisms was evaluated for feasibility regarding our primary selection criteria: weight. In evaluating the potential weight of the systems and the design specification needed (7 lbs.) it was agreed that a pneumatic or hydraulic system was impractical for this application. The need for cylinders, reservoirs, or pumps increases the weight beyond acceptable terms. Additionally, assuming the weight could be kept to within specification, the relative benefits of such a system would be minimal with regards to the competing systems. The original concepts called for electromechanically actuating the foot shift lever. The required displacement for each gear shift at this location is 17o. Since the system ratchets with each gear change, the lever would return to a standard position after each shift. The required torque at this point is about 150 in-lbs. For this concept, rotary solenoids were first considered, however found to have insufficient torque for the application along with stepper motors. Concepts were generated using linear solenoids since the lever arm could be used to increase applied torque from the linear source. On that track, the following concepts were generated.

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Shift Actuation Concepts: Concept 1: One Push-Pull Solenoid

Figure 5: Concept utilizing push/pull linear solenoid. Concept 2: Two Pull Solenoids

Control line

Solenoid (remote mounted)

Shift drum

Shift lever

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Solenoids (remote mounted) Control lines

Figure 6: Concept utilizing two pull solenoids. In each of the designs, the shift lever is actuated by the solenoid(s) connected via control lines. The shift lever changes the gears by moving upward or downward. The rotation is approximately 17 degrees in either direction and the action is ratcheted so that the shift lever always returns to the reference position shown.

Shift drum

Shift lever

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Upon further investigation, both concepts were found to be infeasible due to solenoid parameters. A long lever arm reduced the amount of linear force necessary, but increased the needed displacement. When suitable solenoids were found, they were either too heavy or consumed too much power (~1500W). With a transmission physically present (it had not yet arrived during the generation of the previous concepts) a new approach was investigated. Instead of actuating the shift lever, the shift drum would be actuated instead. The displacement requirement is greater, 60 degrees, but the torque requirement is much lower (~20-50 in.-lbs.). Concept 3: Direct Shift Drum Actuation

Figure 7: External view of shift drum

Figure 8: Internal view of shift drum

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Figure 9: Shift fork

Figure 10: Shift drum removed from transmission The direct shift drum actuation concept planned to utilize a stepper motor or servo directly mated to the shift drum , (1) in Figure 8, via the existing holes for the pins (4) in Figure 7. The motor or servo would rotate to specific positions for each of the gears. This concept was eliminated due to extremely limited space in the proposed mounting area, and therefore an alternative concept was generated.

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Concept 4: Semi-Direct Shift Fork Actuation With this concept, each of the three shift forks, (2) in Figure 8, are manipulated with the use of control cables. The electromechanical device(s) are mounted remotely, so immediate space concerns are irrelevant.

Figure 11: Model of new shift drum In the model in Figure 11 the shift forks will sit in the grooves cut in the side of the shift drum. One groove is not visible from this angle. Each of the forks will have a cable attached to pull the fork in both directions along the axis of the drum. The

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control lines will feed out through the hollow center of the drum. The exact routing of the control lines has yet to be determined, but should not prove to be a critical concern. Originally, linear solenoids were thought to be the best option for electromechanical device for this concept. Upon closer inspection of the shift drum, it was seen that each shift fork would need to locate to three discrete positions. Since linear solenoids lack the ability to hold more than one position, and that the solenoids would need to be energized to hold certain positions indefinitely, stepper motors are the next logical choice.

Figure 12: Spur gear stepper motor

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The stepper motor in Figure 12 is not the exact model to be used, however serves as a general representation. To develop the required 35-50 lbs. of linear force to move each of the shift forks, a .5 inch diameter pulley will be attached to the stepper motor. The motor’s 228 oz-in torque output exceeds the ideal value of 200 oz-in. A set of three stepper motors will be required to move the shift forks, and thus packaging is something of a concern for the future. Since the motors can be remote mounted, this should not be a major concern. The weight of each motor is 1.6 lbs. giving a total motor weight of 4.8 lbs.

Electrical Control System: Based on the conceived mechanical designs, an electrical concept was created to determine when to change gears for optimal smoothness, efficiency, and performance using sensors on the ATV. For the most part, the input variables into the Programmable Logic Controller (PLC) can be obtained through existing sensors on the ATV. The PLC will be powered by a 12 V dc input voltage. See Figure 1 for the control system block diagram. The throttle position sensor is used to monitor the position of the throttle in the engine. This is achieved by utilizing a potentiometer, providing a resistance based on the throttle position. The potentiometer will be dived into eight sections: fully closed, fully opened, and six intermediate positions. Each section indicates a different range of the throttle position. This analog sensor can be found existing on the ATV in the carburetor and can be used to help determine the engine load. The RPM (revolutions per minute) sensor is used to monitor the RPM of the engine. This sensor may be found stock on the ATV in the Ignition Control System. In the event that this sensor is not found on the ATV, it can be purchased with little extra effort. This sensor is an analog input into the PLC. When used in conjunction with the throttle position sensor, the engine load can be determined. The Shift Drum Indicator sensor monitors the current gear of the transmission. This analog sensor monitors the rotation of the shift drum and indicates the current gear. This again can be found stock on the ATV. This input indicating current gear will also be an output. Shift buttons will be utilized to shift the gear positions. Two buttons will be used, one to up-shift and one to down-shift. The shift actuator will be used to drive the stepper motors. There will be three motors in total, each getting a separate input. This is needed since each of the shift forks will need to be in different positions at different times for each individual gear.

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The ignition attenuation will also be controlled. The precise system that will handle this will be controlled by the PLC. Whether it will control the spark attenuation directly (internally) or indirectly (externally via relay or other device) has yet to be determined.

PROGRAMMABLE LOGIC CONTROLLER

THROTTLE POSITIONMeasures load (with RPM)

Stock on carburetor.Analog.

RPMMeasures load (with throttle)

Stock on Ignition Ctrl SysOr buyAnalog

SHIFT DRUM INDICATORIndicates current gear.

Stock.Analog

SHIFT BUTTONSUp shift and downshift button.

Digital.

SHIFT ACTUATOR3 outputs (1 for each motor)

Digital

GEAR INDICATORFeatureDigital

IGNITION ATTENUATIONFrom ignition ctrl sys.

Digital

INPUTS: OUTPUTS:

Figure 13: Control system block diagram

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Ergonomics Design for Gear Button Controls: The goal of the Polaris ESMT team is to provide a push-button shifting system that is ergonomically easily accessible to the driver, even in the most challenging environments and terrain. This system will be implemented on the Polaris Outlaw 525 high performance ATV. The picture below (Figure 14) shows the front of the Polaris Outlaw 525 from the driver’s perspective. The left side of the handle bar contains the start, lights, and engine kill button control system. The gas tank is also located in the center, and the throttle control mechanism on the right.

Figure 14: Rider’s view on the Outlaw 525 The picture (Figure 15) explains the current features of the left handle bar of the Polaris ATV 525.

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Headlight Controls

Engine Kill Switch

Start Press/Switch Button

Figure 15: Rider’s view of left hand controls The features of the stop-light-engine kill button control system were designed by Polaris to suit driver accessibility based on seating and handling position. The picture below (Figure 16) shows the location of the throttle mechanism box to be on the right side of the handle bars.

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Throttle Mechanism Box

Throttle Lever

Figure 16: Rider’s view of right hand controls The analysis required for the design of the gear button control system must meet the following requirements:

1. Location of the button controls – Left, Center or Right 2. Shape - minimal shape – square, rectangle, hexagonal, or polygonal to meet the physical condition of the driver. 3. Dimensions or Size 4. Environmental Conditions – Rain, Snow, Desert and others 5. Satisfaction

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6. Quality Assurance There are two optional gear button designs for the ATV to be displayed and manufactured. Both feature up and down shift buttons along with other gear indicator displays. Below is the design analysis for button-controls to be placed on the left handling bar of the ATV. Gear Button Control Concepts: Option 1

1

2

3

4

5

Electric Gear Number

Indicator

Figure 17: Ergonomics concept 1 The above electric gear number indicator will be computerized to read out the current gear, giving the rider a clear reading of the gear. The indicator screen will be located in the center, if possible. This gear button box will be placed on the left side of the handling bar on the ATV next to the start-light-engine boxes. This would give the rider easy access in controlling the gear buttons box with his left hand while allowing his right hand to control the throttle. When attached closely to the start button box, the rider would be able to justify his handling position on this gear button box. In the

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gear button box, the shape of the upward and downward button might be press- handed, like a hexagonal button that gives a clear symbol which makes it easier for driver to recognize and control the ATV. All of the buttons in the gear button box will have bright colors and letters, depending on the customer’s preference. These buttons will be made up of either aluminum or black plastic, to make it stable and durable.

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Option 2 Figure 18: Ergonomics concept 2 The gear buttons show the location of all button controls to be displayed and provides clear visibility to the driver. The toggle switch for different gear buttons will start from 1 to 5. The upward and downward button will be hand pressed. If the customer does not want the gear button box to be mounted on the left handling bar, wants it to resemble a rectangle, and wants it to be located close to the fuel tank, it would be considered the best option since it has flexible dimensions and can be attached below the left handling bar. This gives the driver ease of control and view towards the gear button box, according to the sitting and handling position of the driver. The reason for this gear button to be placed on the left side of the handling bar is that the right hand controls the throttle mechanism. Task analysis to be done for both options:

1. Location – The gear button should be located on the left side of the handling bar. 2. Shape – Circular, Hexagonal, or Rectangle Box – specification for length, breadth, and radius are needed. 3. Dimensions/Size – depending on the shape of buttons, specification needed 4. Environmental Conditions – the gear button should be made of aluminum or plastic if applicable. 5. Satisfaction – Driver, Customer -Polaris 6. Quality Assurance – Button controls, Electrical/mechanical parts, Durable, Water-resistant.

1 2 3 4 5

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Suggestions: - - Red Warning Indicator Button to be displayed on the center for low fuel Concern:- - Will it function properly, connecting to the electrical and mechanical components? Bill of Materials for Design of the Gear Button Boxes: Item Units Parts Make or Buy Process Cost 1. 2 Hexagonal Button Switch B Plastic $10 2. 1 1-5 Gear Button Toggle Switch B ? $10 3. 1 Gear Box Button M Lathe, Tools $20 Gear Buttons Design Specification:- Dimensions Hexagonal Button Switch

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1-5 Gear Button Toggle Switches Gear Button Box

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Test Bed Concept Development:

Figure 19: Test bed concept sketch Test Bed Base: For the base of the test bed, a rectangular metal sheet (measuring 20” x 30”) will be used. The mounting bracket and the electric motor will be screwed to it. The holes to be drilled in the test bed will be ½” diameter. Electric Motor: The electric motor to be used will generate 3450 RPM and ¾ Horsepower. The test bed will be set up in the machine shop. The voltage and current for the motor will depend upon how much voltage the machine shop can provide coupled with the maximum allowable current to be used without causing any short circuits. After consulting with the machine shop the available voltage is 220V

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single phase and the allowable current 20 Amps although 30 Amps is possible. The rotation will need to be clockwise since the input shaft can only rotate in one direction. Input Shaft: The input shaft will be connected to the electric motor and the input gear. The Outer Diameter of the input shaft will be 1 inch with a needle bearing (1-1/4”) to hold the shaft in place.

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Figure 20: Input gear sketch Input/ Output Gear: The OD for the input gear is 2.75” while the OD for the output gear is 5.25”. The gear ratio is 0.524.

Figure 21: Input gear close-up picture

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Figure 22: Clutch basket close-up Mounting Bracket: The mounting bracket will be made out of metal and the purpose of it will be to hold the transmission in place with no movement. Output Shaft: The output shaft will connect the output gear to the flywheel. The shaft would be a diameter of 5/8” inch and made of metal. The length of the shaft will be around 6”, not too long since the diameter of the shaft is small.

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Flywheel: The flywheel is attached to the output shaft. Weights in the form of circular steel discs, will be added to the shaft. The diameter of the weights cannot exceed 6 inches due to limited space. Each weight will have a thickness of 1/2”. A removable locating pin with a diameter of 7/8” will be added to the end of the shaft to avoid the weights falling off. A hole of diameter 0.3115” (after looking at McMaster) and depth of ½” will be drilled to accommodate this. Proposed Bill of Materials:

Item Estimated CostNeedle Bearing $6.49 Output Shaft $30 Metal Base Sheet Electric Motor (3/4HP, 3450 RPM) $200 Electric Motor Controller $40 Stainless Steel Discs $49.57 Each Removable Locating Pin $8.84

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Design Specifications Updated 1 February 2007 Specification

Number Customer Need

Number Design Specification Importance Unit of Measure Marginal Value Ideal Value

1 10, 2, 6, 8 Weight 10 lbs. 7 < 7 2 13 Shift Time 8 sec. 0.1 < .1 3 6, 7, 9 Cost 10 US$ 250 < 200 4 11, 13 Shift Lever rotation 9 degrees 17 20 5 11, 13 Shift lever torque 9 in-lbs 150 150 6 11, 13 Shift drum rotation 9 degrees 60 60 7 11, 13 Shift drum torque 9 in-lbs 30 50 8 11, 13 Shift drum rotation time 9 sec. 0.04 0.02 9 11, 13 Shift fork displacement 9 inches 0.5 0.5

10 11, 13 Shift fork force 9 lbs. 25 50 11 11, 13 Minimum upshift speed 7 RPM 3000 3000 12 11, 13 Maximum upshift speed 7 RPM 9500 9500 13 11, 13 Maximum downshift speed (5->4) 8 RPM 7500 7500 14 11, 13 Maximum downshift speed (4->3) 8 RPM 7500 7500 15 11, 13 Maximum downshift speed (3->2) 8 RPM 7000 7000 16 11, 13 Maximum downshift speed (2->1) 8 RPM 4200 4200 17 15, 6, 7, 8, 16 Expected System Life 7 years 5 10 18 5, 6 Voltage 5 Volts 12 12

Feature Number

Customer Need Number Feature Importance Unit of

Measure Marginal Value Ideal Value

1 1, 9 Push-button Shift Control 9 binary Yes Yes 2 4, 1, 3 Reverse Lockout 10 binary Yes Yes

Appendix: A

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Goal Number Customer Need Number Goal Importance Unit of

Measure Marginal Value Ideal Value

1 12, 8, 13 Acceleration 9 sec. comparable to manual faster than manual

2 5, 6, 9 Minimal Engine/Transmission Case Modification 10 subjective Minor Mounting holes only

3 11, 7 Shift Smoothness 9 subjective comparable to manual smoother than manual

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Appendix B Needs Assessment Updated 11 January 2007 The ESMT is safe *** (1) The ESMT is easy to use * (2) The ESMT is compact and ergonomically sound ** (3) The ESMT has built in safety features *** (4) The ESMT retains a reverse lockout feature The electronic-shifted, manual transmission (ESMT) is a valuable investment to Polaris ** (5) The ESMT is easy to manufacture ** (6) The ESMT is economically viable to manufacture and sell ** (7) The ESMT improves brand name recognition ** (8) The ESMT offers visible quality improvements from previous models *** (9) The ESMT will allow Polaris to utilize one powertrain for all ATV’s The ESMT system (less transmission) is lightweight (under 7 lbs.) (10) The ESMT offers performance benefits *** (11) The shifts are made smoothly ** (12) Acceleration from a dead stop is crisp and consistent ** (13) Shifts are made quickly The ESMT is durable and reliable *** (14) The ESMT is reliable under all weather conditions and in all-terrain ** (15) The ESMT lasts the lifetime of product (ATV) ** (16) The ESMT is comprised of quality materials

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