FC_DoubleCrankTransformation

FC_DoubleCrankTransformation - General Information

Overview

Type:	Function
Available as of:	V1.0.3.0
Versions:	Current version

Task

Transformation of a double crank

Description

From the input-side angle of a double crank this function calculates the output-side angle (kinematic transformation) and from the input-side impressed torque, it calculates the resulting output-side torque (mechanical transformation). The meaning of the quantities involved can be taken from the following figure. The angles are measured in the mathematically positive sense (anti-clockwise), starting from the positive X direction. It must be noted here that in the case of some double cranks - due to the mechanical situation - not all input-side angles can be moved to. Moreover it must be taken into account that, as a rule, there are two associated output-side angles for one input-side angle i.e. that the reverse transformation is not clear (see parameter i_diSector). It is the task of the user to select the angle that is reasonable for the application.

As the double crank is a symmetrical mechanism, no separate functions for forward and reverse transformation are required. The reverse transformation is obtained by the following change of the parameters: i_lrRadius1 -> i_lrRadius2, i_lrRadius2 -> i_lrRadius1, i_lrXOffset -> - i_lrXOffset, i_lrYOffset -> - i_lrYOffset.

NOTE: This function only serves for calculating the transformation of the crank. A transfer of position set values to axes does not take place. An advantage of this method is that the function can be combined with other mechanical calculation POUs without any problems.

Interface

Input	Data type	Description
i_lrRadius1	LREAL	Length of the input-side radius, value range: > 0.0
i_lrPushRod	LREAL	Length of the connecting push rod, value range: > 0.0
i_lrRadius2	LREAL	Length of the output-side radius, value range: > 0.0
i_lrXOffset	LREAL	X-offset between input-side and output-side revolute joint. This value is provided with a sign.
i_lrYOffset	LREAL	Y-offset between input-side and output-side revolute joint. This value is provided with a sign.
i_diSector	DINT	As already explained above, the double crank transformation is not unique as a rule, that is, there exist two output-side angles which are associated with the input-side angle i_lrAngularPosition1. If i_diSector = 1, then the first of the two solutions is output to q_lrAngularPosition2; if i_diSector = 2, then the second solution is output.
i_lrAngularPosition1	LREAL	Angle specified on the input side
i_lrTorque1	LREAL	Torque specified on the input side

Output	Data type	Description
q_etDiag	GD.ET_Diag	General library-independent statement on the diagnostic. A value not equal to ET_Diag.Ok corresponds to an diagnostic message.
q_etDiagExt	ET_DiagExt	POU-specific output on the diagnostic. q_etDiag = ET_Diag.Ok -> Status message q_etDiag <> ET_Diag.Ok -> Diagnostic message
q_lrAngularPosition2	LREAL	Output-side angle calculated from i_lrAngularPosition1. If several solutions exist, the parameter i_diSector determines which will be output.
q_lrTorque2	LREAL	Output-side torque calculated from i_lrTorque1.

Diagnostic Messages

q_etDiag	q_etDiagExt	Enumeration value	Description
OK	Ok	0	Ok
InputParameterInvalid	AngularPosition1Range	68	AngularPosition1 is outside the valid range
InputParameterInvalid	PushRodRange	64	PushRod is outside the valid range.
InputParameterInvalid	Radius1Range	29	Radius1 is outside the valid range.
InputParameterInvalid	Radius2Range	30	Radius2 is outside the valid range.
InputParameterInvalid	XOffsetRange	67	XOffset is outside the valid range.
InputParameterInvalid	YOffsetRange	174	YOffset is outside the valid range.

AngularPosition1Range

Enumeration name:	AngularPosition1Range
Enumeration value:	68
Description:	AngularPosition1 is outside the valid range

Issue	Cause	Solution
-	The outputs q_lrLinearPosition2 and q_lrTorque2 cannot be calculated for the value defined for i_lrAngularPosition1.	Verify i_lrAngularPosition1 Verify all parameters that are part of the calculation: i_lrRadius1, i_lrPushRod, i_lrRadius2, i_lrXOffset, i_lrYOffset, i_diSector

Issue

Cause

Solution

The outputs q_lrLinearPosition2 and q_lrTorque2 cannot be calculated for the value defined for i_lrAngularPosition1.

Verify i_lrAngularPosition1

Verify all parameters that are part of the calculation: i_lrRadius1, i_lrPushRod, i_lrRadius2, i_lrXOffset, i_lrYOffset, i_diSector

Enumeration name:	Ok
Enumeration value:	0
Description:	Ok

The transformation has been completed successfully.

PushRodRange

Enumeration name:	PushRodRange
Enumeration value:	64
Description:	PushRod is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrPushRod, a negative value has been applied.	At the input i_lrPushRod, a value greater than 0 must be transferred.

Radius1Range

Enumeration name:	Radius1Range
Enumeration value:	29
Description:	Radius1 is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrRadius1, a negative value has been applied.	At the input i_lrRadius1, a value greater than 0 must be transferred.

Radius2Range

Enumeration name:	Radius2Range
Enumeration value:	30
Description:	Radius2 is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrRadius2, a negative value has been applied.	At the input i_lrRadius2, a value greater than 0 must be transferred.

XOffsetRange

Enumeration name:	XOffsetRange
Enumeration value:	67
Description:	XOffset is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrXOffset, a number whose value is smaller than Gc_lrZeroTolerance has been applied.	i_lrXOffset must not be 0.

YOffsetRange

Enumeration name:	YOffsetRange
Enumeration value:	174
Description:	YOffset is outside the valid range.

Issue	Cause	Solution
-	At the input i_lrYOffset, a number whose value is smaller than Gc_lrZeroTolerance has been applied.	i_lrYOffset must not be 0.