ControlOriented Identification of an Electromechanically Actuated Metal Vbelt CVT

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• Control-Oriented Identification of an
  Electromechanically Actuated Metal V-belt CVT

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Outline

• Continuously Variable Transmission
• Electromechanical Actuation
• Simulation Model
• Control Problem
• Identification
• Conclusions

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Continuously Variable Transmission

• How?
• 2 pulleys, each 2 sheaves
• VDT pushbelt
• Bands elements
• Hydraulic actuation
• Drawbacks
• Energy consumption
• Controllability Ratio and clamping force

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Electromechanical Actuation

• Goals
• Lower power consumption
• High actuation stiffness
• Result
• Servomotor for ratio
• Servomotor for clamping force
• Energy exchange

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Simulation Model
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Simulation Model

• Algebraic description of variator
• Reduce DOF
• Slip dependent belt torque
• Transient losses
• Ide or Shafai
• High order, nonlinear model
• Not suitable for control design
• Identification for linearized model

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Control Problem

• CVT ratio control
• Prevent CVT from excessive slippage
• Efficient variator operation

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Identification Technique

• Approximate Realization

• Perform step responses
• Form Hankel matrices
• Calculate Hankel singular values
• Obtain descrete state space system

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Identification Technique

• Closed loop identification
• Sensitivity

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Identification Results

• Excitation on primary servomotor
• Pulley position output

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Identification Results

• Excitation on secondary servomotor
• Slip output

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Identification Results - Plant
Low Medium Overdrive
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Identification Results - Plant
Low Medium Overdrive
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Identification Results - Plant
Low Medium Overdrive
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FTP72 driving cycle
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Belt torque
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Primary Clamping Force
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Slip
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Electrical power consumption
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Conclusions

• Simulation model
• High order, nonlinear
• Not suitable for control design
• Approximate realization
• Linearized model suitable for control design
• Ratio and slip dependent system
• Electromechanical actuation
• High bandwidth
• Low power consumption

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Identification Results - Sensitivity
Low Medium Overdrive
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Identification Results - Sensitivity
Low Medium Overdrive
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Approximate Realization - Details