CVT Controller

Continuously variable transmission controller

Libraries:
Powertrain Blockset / Transmission / Transmission Controllers

Description

The CVT Controller block implements a push belt continuously variable transmission (CVT) controller. The block uses standard pulley and geometric equations to calculate the kinematic setpoints for the CVT variator. You can use the block to control a CVT.

Pulley Kinematics

Using the physical dimensions of the system, the block calculates the primary and secondary variator positions that meet the pulley ratio request.

The figure and equations summarize the geometric dependencies.

$\begin{array}{l} C_{d i s t} = r p_{m a x} + r_{g a p} + r_{s e c_m a x} \\ L_{0} = f (r p_{m a x}, r s_{m a x}, r p_{m i n}, r s_{m i n}, C_{d i s t}) \\ r a t i o_{c o m m a n d} = f (r a t i o_{r e q u e s t}, r a t i o_{m a x}, r a t i o_{m i n}) \\ r_{p r i} = f (r_{0}, r a t i o_{c o m m a n d}, C_{d i s t}) \\ r_{\sec} = f (r_{0}, r a t i o_{c o m m a n d}, C_{d i s t}) \\ x_{p r i} = f (r_{0}, r_{p r i}, θ_{w e d g e}) \\ x_{\sec} = f (r_{0}, r_{\sec}, θ_{w e d g e}) \end{array}$

The equations use these variables.

ratio_request	Pulley gear ratio request
ratio_command	Pulley gear ratio command, based on request and physical limitations
r_gap	Gap distance between variator pulleys
C_dist	Distance between variator pulley centers
rp_max	Maximum variator primary pulley radius
rs_max	Maximum variator secondary pulley radius
rp_min	Minimum variator primary pulley radius
rs_min	Minimum variator secondary pulley radius
r_o	Initial pulley radii with gear ratio of `1`
L_o	Initial belt length, resulting from variator specification
x_pri	Variator primary pulley displacement, resulting from controller request
x_sec	Variator secondary pulley displacement, resulting from controller request
r_pri	Variator primary pulley radius, resulting from controller request
r_sec	Variator secondary pulley radius, resulting from controller request
Θ_wedge	Variator wedge angle
Φ	Angle of belt to pulley contact point
L	Belt length, resulting from variator position

Examples

Build Conventional Vehicle Model

Build a vehicle with an internal combustion engine using the conventional vehicle reference application.

Ports

Inputs

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DirReq — Direction request
`scalar`

Direction request, Dir_req, controlling the direction, either forward or reverse. Dir equals 1 for forward motion. Dir equals -1 for reverse.

$D i r = {\begin{matrix} 1 when D i r_{r e q} \geq 0 \\ - 1 when D i r_{r e q} < 0 \end{matrix}$

PllyRatioReq — Pulley ratio request
`scalar`

CVT pulley ratio request, ratio_request.

Output

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Info — Bus signal
bus

Bus signal containing these block calculations.

Signal		Description	Variable	Units
`Radius`	`PriRadius`	Variator primary pulley radius, resulting from controller request	r_pri	m
	`SecRadius`	Variator secondary pulley radius, resulting from controller request	r_sec	m
	`InitPllyRadius`	Initial pulley radii with gear ratio of 1	r_o	m
`RatioAdj`		Pulley gear ratio command, based on request and physical limitations	ratio_command	N/A
`RatioMax`		Maximum pulley ratio	ratio_max	N/A
`RatioMin`		Minimum pulley ratio	ratio_min	N/A
`PriDispCmd`		Variator primary pulley displacement, resulting from controller request	x_pri	m
`SecDispCmd`		Variator secondary pulley displacement, resulting from controller request	x_sec	m

Dir — Direction request
`scalar`

Direction request, Dir_req, controlling the direction, either forward or reverse. Dir equals 1 for forward motion. Dir equals -1 for reverse.

$D i r = {\begin{matrix} 1 when D i r_{r e q} \geq 0 \\ - 1 when D i r_{r e q} < 0 \end{matrix}$

PriDispCmd — Primary pulley displacement
`scalar`

Variator primary pulley displacement, x_pri, in m.

SecDispCmd — Secondary pulley displacement
`scalar`

Variator secondary pulley displacement, x_sec, in m.

Parameters

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Kinematics

Maximum variator primary pulley radius, rp_max — Radius
`.08` (default) | `scalar`

Maximum variator primary pulley radius, rp_max, in m.

Maximum variator secondary pulley radius, rs_max — Radius
`.07` (default) | `scalar`

Maximum variator secondary pulley radius, rs_max, in m.

Minimum variator primary pulley radius, rp_min — Radius
`.03` (default) | `scalar`

Minimum variator primary pulley radius, rp_min, in m.

Minimum variator secondary pulley radius, rs_min — Radius
`.03` (default) | `scalar`

Minimum variator secondary pulley radius, rs_min, in m.

Gap distance between variator pulleys, rgap — Specify crown wheel connection
`.025` (default) | `scalar`

The gap between the secondary and primary pulleys, r_gap, in m. The figure shows the pulley geometry.

Variator wedge angle, thetawedge — Specify crown wheel connection
`11` (default) | `scalar`

Variator wedge angle, Θ_wedge, in deg.

References

[1] Ambekar, Ashok G. Mechanism and Machine Theory. New Delhi: Prentice-Hall of India, 2007.

[2] Bonsen, B. Efficiency optimization of the push-belt CVT by variator slip control. Ph.D. Thesis. Eindhoven University of Technology, 2006.

[3] CVT How Does It Work. CVT New Zealand 2010 Ltd. February 10, 2011. Accessed April 25, 2016.

[4] Klaassen, T. W. G. L. The Empact CVT: Dynamics and Control of an Electromechanically Actuated CVT. Ph.D. Thesis. Eindhoven University of Technology, 2007.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017a

CVT Controller

Description

Pulley Kinematics

Examples

Build Conventional Vehicle Model

Ports

Inputs

DirReq — Direction request scalar

PllyRatioReq — Pulley ratio request scalar

Output

Info — Bus signal bus

Dir — Direction request scalar

PriDispCmd — Primary pulley displacement scalar

SecDispCmd — Secondary pulley displacement scalar

Parameters

Maximum variator primary pulley radius, rp_max — Radius .08 (default) | scalar

Maximum variator secondary pulley radius, rs_max — Radius .07 (default) | scalar

Minimum variator primary pulley radius, rp_min — Radius .03 (default) | scalar

Minimum variator secondary pulley radius, rs_min — Radius .03 (default) | scalar

Gap distance between variator pulleys, rgap — Specify crown wheel connection .025 (default) | scalar

Variator wedge angle, thetawedge — Specify crown wheel connection 11 (default) | scalar

References

Extended Capabilities

C/C++ Code Generation Generate C and C++ code using Simulink® Coder™.

Version History

See Also

DirReq — Direction request
`scalar`

PllyRatioReq — Pulley ratio request
`scalar`

Info — Bus signal
bus

Dir — Direction request
`scalar`

PriDispCmd — Primary pulley displacement
`scalar`

SecDispCmd — Secondary pulley displacement
`scalar`

Maximum variator primary pulley radius, rp_max — Radius
`.08` (default) | `scalar`

Maximum variator secondary pulley radius, rs_max — Radius
`.07` (default) | `scalar`

Minimum variator primary pulley radius, rp_min — Radius
`.03` (default) | `scalar`

Minimum variator secondary pulley radius, rs_min — Radius
`.03` (default) | `scalar`

Gap distance between variator pulleys, rgap — Specify crown wheel connection
`.025` (default) | `scalar`

Variator wedge angle, thetawedge — Specify crown wheel connection
`11` (default) | `scalar`

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.