Scara_4dof

The "Scara_3dof" axes group describes a horizontal articulated robot with four Cartesian degrees of freedom (X, Y, Z and C).

Axis group Scara_4dof: Overview/ Mechanic data

Axis legend: x - red y - green z - blue

Degrees of freedom (dof)

Degrees of freedom (dof)

Translation

Rotation

Drives

A3

A1, A2, A4

Tool

x, y, z

C

MCS position

  • Z axis is aligned with the first rotary axis.
  • When angle setting A1 = 0 °, x axis points towards A2.
  • Y axis results from the Cartesian coordinate system.

TCS position, relatively to the MCS

  • Z axis in direction of impact of the robot Aligned opposite to z MCS .
  • In zero position, x TCS and x MCS are parallel.
  • In zero position, the origin is z MCS = 0.

Zero position of the drives

  • In the zero position of the drives, the robot is in extended position.
  • Both robot elements are aligned along the x MCS axis.
  • The end effector (TCS) is on z MCS = 0.

Configuration

The angular setting of the Scara_4dof kinematics is (without considering the axis limitations) ambiguous for every required target position in the workspace (right and left projection).

The axes group property Configuration (only read access) is used as follows:

<axes group instance>.Configuration[1] := {-1, 0, 1}

Characteristic

Value

Meaning

Configuration[1]

-1

Left projection (A2 > 0 °)

0

Singular joint setting (A2 = 0 °)

1

Right projection (A2 < 0 °)

Comments on configuration

Continuous path movements

In case of continuous path movements, the configuration cannot be changed.

  • The robot approaches the target position in the start configuration.
  • If the target position is given in the ACS to force a configuration change, the movement is not carried out and refused with an error at the FB.

FBs for continuous path movements:

Point-to-point movements

In case of point-to-point movements, the configuration can be changed.

  • If the target point is given in the ACS, the angle A2 defines the projection in the target position.
  • If the target coordinates of the motion are defined in the MCS or a PCS, the aiTargetConfiguration input is used for the conversion into axis angle for the two MC_MoveDirect FBs.

FBs for point-to-point movements:

Singularities

The singular setting A2 = 0 ° can be exclusively approached and left via the FBs MC_MoveDirectAbsolute / MC_MoveDirectRelative and single-axis movements of the drives. Linear, circular and single-axis movements on the main axes x, y, z cannot approach this position.

 

Parameter

A complete list of all kinematics-independent parameters can be found in the section

Short overview of all parameters

Arm length L1 (index offset 3, subindex 2)

Length of element 1 (L1)

  • Limits: > 0

Setting range (min. value | unit | max. value)

Lenze setting

0

mm

2147483647

0 mm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Arm length L2 (index offset 3, subindex 3)

Length of element 2 (L2)

  • Limits: > 0

Setting range (min. value | unit | max. value)

Lenze setting

0

mm

2147483647

0 mm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Coulomb friction A1 (index offset 3, subindex 51)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm

2147483647

0 Nm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Coulomb friction A2 (index offset 3, subindex 52)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm

2147483647

0 Nm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Coulomb friction A3 (index offset 3, subindex 53)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm

2147483647

0 Nm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Coulomb friction A4 (index offset 3, subindex 54)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm

2147483647

0 Nm

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Viscous friction A1 (index offset 3, subindex 57)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm/(rad/s)

2147483647

0 Nm/(rad/s)

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Viscous friction A2 (index offset 3, subindex 58)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm/(rad/s)

2147483647

0 Nm/(rad/s)

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Viscous friction A3 (index offset 3, subindex 59)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm/(rad/s)

2147483647

0 Nm/(rad/s)

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Viscous friction A4 (index offset 3, subindex 60)

Setting range (min. value | unit | max. value)

Lenze setting

0

Nm/(rad/s)

2147483647

0 Nm/(rad/s)

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Gravitation x (index offset 3, subindex 71)

Setting range (min. value | unit | max. value)

Lenze setting

-10

m/s²

10

0 m/s²

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Gravitation y (index offset 3, subindex 72)

Setting range (min. value | unit | max. value)

Lenze setting

-10

m/s²

10

0 m/s²

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Gravitation z (index offset 3, subindex 73)

Setting range (min. value | unit | max. value)

Lenze setting

-10

m/s²

10

-9.81 m/s²

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter1 (index offset 3, subindex 74)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter2 (index offset 3, subindex 75)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter3 (index offset 3, subindex 76)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter4 (index offset 3, subindex 77)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter5 (index offset 3, subindex 78)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter6 (index offset 3, subindex 79)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter7 (index offset 3, subindex 80)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter8 (index offset 3, subindex 81)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter9 (index offset 3, subindex 82)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

Torque feedforward control: minimum parameter10 (index offset 3, subindex 83)

Setting range (min. value | unit | max. value)

Lenze setting

0

2147483647

0

Read access Write access Can only be changed in "GroupDisabled" state No download

FLOAT_64

A minimal dynamic parameter describes a mathematical grouping that may comprise several physical masses, mass inertias and geometric lengths. Together, these result in a readily identifiable parameter set and a time-efficient calculation rule for feedforward control.

For a description of the variables (Inertia<1 ... 4>, Mass<1 ... 4> etc.) and their reference coordinates, refer to the FB L_MK4P_DynamicParScara_4dof .

Note!

In contrast to the FB L_MK4P_DynamicParScara_4dof , the values in the following parameters are expressed in SI units [kg], [m] and [kgm²].

MinimalDynamicParameter 5 := Mass2 * xDistCenterOfMass2 +

Mass3 * xDistCenterOfMass3

MinimalDynamicParameter 6 := Mass2 * yDistCenterOfMass2 +

Mass3 * yDistCenterOfMass3

MinimalDynamicParameter 7 := Mass3 + Mass4

MinimalDynamicParameter 8 := lnertia4

MinimalDynamicParameter 9 := Mass4 * xDistCenterOfMass4

MinimalDynamicParameter 10 := Mass4 * yDistCenterOfMass4

Related topics

Traversing ranges of connected axes

Coordinate systems

Basics of the tool management

Considering differential drives