Design and Prototype Build of the Interfaces of a SteerByWire Assembly

1
Design and Prototype Build of the Interfaces of a
Steer-By-Wire Assembly

• Javier Angulo
• Alan Benedict, Team Leader
• Amber Russell, Team Manager
• Kurush Savabi
• Dr. Sohel Anwar, Faculty Advisor Sponsor
• Dr. Hazim El-Mounayri, Course Instructor

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Overview

• Purpose Objective
• Requirements Targets
• Concept Generation Evaluation
• Product Generation Evaluation
• Conclusions Recommendations

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Introduction

• Overall Purpose
• Create a steer-by-wire system parallel to that
  of an automobile for use in laboratory

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Introduction (continued)
Overall Steer-By-Wire System
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Objectives of Design

• Objectives
• Design of an interface between a standard
  automotive rack-and-pinion steering assembly and
  electric motors.
• Design of an interface between the same
  rack-and-pinion steering assembly and angle
  position sensors
• Design of a stand to support the entire system
  and provide reaction forces to rack

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Requirements and Targets

• Functionality and safety
• Benchmark Visteon-GM Sequel

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Requirements and Targets (continued)
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Concept Development Evaluation

• Development Process
• Functional Decomposition
• Function Concept-Mapping
• Evaluation Process
• Feasibility Testing
• Go/No-Go Screening
• Decision Matrices
• Failure Mode Effects Analysis (FMEA)

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Final Concept

• Motor to Rack-and-Pinion Interface
• Gear Train
• Motor to Motor Interface
• Gear Train
• Sensor to Sensor Interface
• Stackable Sensors / Shaft
• Sensor to Rack and Pinion Interface
• Direct Shaft
• Metal Stand

Motor Controllers
Position Sensors
Motor
Motor
Stacked / Shaft
Rack
Pinion 1
Pinion 2
Gear Train
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Product Generation Evaluation

• Motors Requirements
• Torque of 52 Nm at 67 rpm
• Torque of 20.8 Nm at 133 rpm
• Input voltage of lt60 VDC
• Selected Motor Specifications
• Torque of 52 Nm at 67 rpm
• Torque of 20.8 Nm at 127.4 rpm
• Input voltage of 75 VDC

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Product Generation Evaluation

• Motor Interfaces
• Enables redundancy
• Allows for maintenance

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Product Generation Evaluation

• Stand Requirements
• Max deflection of 12.7mm
• Max stress of 450MPa
• Stand Analysis Results
• Max deflection of 1.83E-4mm
• Max stress of 89.1MPa (Dynamic)
• FOS 3 to 5 (267.3MPa to 445.5MPa)

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Product Generation Evaluation

• Springs
• Spring Requirements of 102 kN/m
• Selected Spring Specifications of 83 kN/m
• Force of 6876 N (to simulate dynamic loading)
• Maximum Stress 104.6 MPa
• Yield Strength of Plate 250 MPa

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Product Generation Evaluation

• Sensors
• Hollow-angle sensors
• Ease of interface
• Zero backlash
• Lack of availability
• Lower accuracy
• Requires less space
• Conventional Potentiometers
• Meet accuracy requirement
• Readily available
• Cost efficient
• Requires gear train interface (backlash)

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Final Design
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Final Design (continued)
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Engineering Requirements
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Questions

• For further questions, please feel free to ask
  the design team or refer to the project report.
  Thank you.

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References

• Cesiel, Daugherty, Gaunt, Development of a
  Steer-by-Wire System for the GM Sequel, SAE
  Technical Paper Series, 2006-01-1173.
• David G. Ullman, The mechanical design process,
  Third edition, McGrawHill, 2003, USA.
• Delphi Non-Contact Multi-Turn Rotary Position
  Sensor, Delphi, www.delphi.com.
• Electric Power Assisted Steering, Visteon,
  2005.
• Matweb, www.matweb.com. March 2007.
• Miller, Duane K., P.E., Use Undermatching Weld
  Metal Where Advantageous Practical Ideas for
  the Design Professional, Welding Innovation,
  Vol. XIV, No. 1, 1997.
• Parker Motion, www.parkermotion.com. April 2007.
• Roy Mech, www.roymech.co.uk/useful_tables/form/wel
  d_strength
• Sensors for Position Measurement
  Single-turn/Multi-turn Steering-angle Sensor,
  Hella International, www.hella.com.