Ubuntu Manpage: kins - kinematics definitions for LinuxCNC

Provided by: linuxcnc-uspace_2.9.4-2ubuntu1_amd64

NAME

       kins - kinematics definitions for LinuxCNC

       For additional information, see the Documents 'Advanced Topics':

          Kinematics

          5-Axis Kinematics

          Switchable Kinematics

SYNOPSIS

       loadrt trivkins (use for most cartesian machines)

       loadrt corexykins

       loadrt genhexkins

       loadrt genserkins

       loadrt lineardeltakins (see separate manpage)

       loadrt maxkins

       loadrt pentakins

       loadrt pumakins

       loadrt rosekins

       loadrt rotarydeltakins

       loadrt rotatekins

       loadrt scarakins

       loadrt tripodkins

       loadrt xyzab_tdr_kins

       loadrt xyzac-trt-kins

       loadrt xyzbc-trt-kins

       loadrt 5axiskins

DESCRIPTION

Rather than exporting HAL pins and functions, these components provide the forward and inverse kinematics
definitions for LinuxCNC.

trivkins - generalized trivial kinematics
Joint numbers are assigned sequentially according to the axis letters specified with the coordinates=
parameter.

If the coordinates= parameter is omitted, joint numbers are assigned sequentially to every known axis
letter ("xyzabcuvw").

Example: loadrt trivkins

Assigns all axis letters to joint numbers in sequence:

x==joint0, y==joint1, z==joint2
a==joint3, b==joint4, c==joint5
u==joint6, v==joint7, w==joint8

Example: loadrt trivkins coordinates=xyz
Assigns: x==joint0, y==joint1, z==joint2

Example: loadrt trivkins coordinates=xz
Assigns: x==joint0, z==joint1

Example: loadrt trivkins coordinates=xyzy
Assigns: x==joint0, y0==joint1, z==joint2, y1==joint3

The default kinematics type is KINEMATICS_IDENTITY. GUIs may provide special features for configurations
using this default kinematics type. For instance, the AXIS GUI automatically handles joint and world
mode operations so that the distinctions between joints and axes are not visible to the operator. This
is feasible since there is an exact correspondence between a joint number and its matching axis letter.

The kinematics type can be set with the kinstype= parameter:

kinstype=1 for KINEMATICS_IDENTITY (default if kinstype= omitted)
kinstype=[b|B] for KINEMATICS_BOTH
kinstype=[f|F] for KINEMATICS_FORWARD_ONLY
kinstype=[i|I] for KINEMATICS_INVERSE_ONLY

Example: loadrt trivkins coordinates=xyz kinstype=b

Use kinstype=B (KINEMATICS_BOTH) for configurations that need to move joints independently (joint mode)
or as coordinated (teleop) movements in world coordinates.

When using the axis gui with KINEMATICS_BOTH, the '$' key is used to toggle between joint and teleop
(world) modes.

An axis letter may be used more than once (duplicated) to assign multiple joints to a single axis
coordinate letter.

Example: coordinates=xyyzw kinstype=B
Assigns: x==joint0, y==joint1 AND joint2, z==joint3, w==joint4

The above example illustrates a gantry configuration that uses duplicated coordinate letters to indicate
that two joints (joint1 and joint2) move a single axis (y). Using kinstype=B allows the configuration to
be toggled between joint and world modes of operation. Homing configuration options are available to
synchronize the final homing move for selected joints -- see the documentation for Homing Configuration.

NOTES for duplicated coordinates:

When duplicated coordinate letters are used, specifying KINEMATICS_BOTH (kinstype=B) allows a gui to
support jogging of each individual joint in joint mode. Caution is required for machines where the
movement of a single joint (in a set specified by a duplicated coordinate letter) can lead to gantry
racking or other unwanted outcomes. When the kinstype= parameter is omitted, operation defaults to
KINEMATICS_IDENTITY (kinstype=1) and a gui may allow jogging based upon a selected axis coordinate letter
(or by a keyboard key) before homing is completed and the machine is still in joint mode. The joint
selected will depend upon the gui implementation but typically only one of the multiple joints in the set
will jog. Consequently, specifying KINEMATICS_BOTH is recommended as it enables support for unambiguous,
independent jogging of each individual joint. Machines that implement homing for all joints (including
the provisions for synchronizing the final homing move for multiple joints) may be homed at machine
startup and automatically switch to world mode where per-coordinate jogging is available.

corexykins - CoreXY Kinematics
X = 0.5*(JOINT_0 + JOINT_1)
Y = 0.5*(JOINT_0 - JOINT_1)
Z = JOINT_2

[KINS]JOINTS= must specify 3 or more joints (maximum 9)

If enabled by the number of [KINS]JOINTS= specified, JOINT_3,4,5,6,7,8 correspond to coordinates
A,B,C,U,V,W respectively.

genhexkins - Hexapod Kinematics
Gives six degrees of freedom in position and orientation (XYZABC). The location of base and platform
joints is defined by HAL parameters. The forward kinematics iteration is controlled by HAL pins. (See
switchkins documentation for more info)

genhexkins.base.N.x
genhexkins.base.N.y
genhexkins.base.N.z
genhexkins.platform.N.x
genhexkins.platform.N.y
genhexkins.platform.N.z
Parameters describing the Nth joint's coordinates.
genhexkins.spindle-offset
Added to all joints Z coordinates to change the machine origin. Facilitates adjusting spindle
position.
genhexkins.base-n.N.x
genhexkins.base-n.N.y
genhexkins.base-n.N.z
genhexkins.platform-n.N.x
genhexkins.platform-n.N.y
genhexkins.platform-n.N.z
Parameters describing unit vectors of Nth joint's axis. Used to calculate strut length correction
for cardanic joints and non-captive actuators.
genhexkins.screw-lead
Lead of strut actuator screw, positive for the right-handed thread. Default is 0 (strut length
correction disabled).
genhexkins.correction.N
Current values of strut length correction for non-captive actuators with cardanic joints.
genhexkins.convergence-criterion Minimum error value that ends iterations with converged solution.
genhexkins.limit-iterations
Limit of iterations, if exceeded iterations stop with no convergence.
genhexkins.max-error
Maximum error value, if exceeded iterations stop with no convergence.
genhexkins.last-iterations
Number of iterations spent for the last forward kinematics solution.
genhexkins.max-iterations
Maximum number of iterations spent for a converged solution during current session.
genhexkins.tool-offset
TCP offset from platform origin along Z to implement RTCP function. To avoid joints jump change
tool offset only when the platform is not tilted.

genserkins - generalized serial kinematics
Kinematics that can model a general serial-link manipulator with up to 6 angular joints. (See switchkins
documentation for more info)

The kinematics use Denavit-Hartenberg definition for the joint and links. The DH definitions are the ones
used by John J Craig in "Introduction to Robotics: Mechanics and Control" The parameters for the
manipulator are defined by HAL pins. Note that this uses a convention sometimes known as "Modified DH
Parameters" and this must be borne in mind when setting up the system. https://w.wiki/NcY

genserkins.A-N
genserkins.ALPHA-N
genserkins.D-N
Parameters describing the Nth joint's geometry.

maxkins - 5-axis kinematics example
Kinematics for Chris Radek's tabletop 5 axis mill named 'max' with tilting head (B axis) and horizintal
rotary mounted to the table (C axis). Provides UVW motion in the rotated coordinate system. The source
file, maxkins.c, may be a useful starting point for other 5-axis systems.

pentakins - Pentapod Kinematics
Gives five degrees of freedom in position and orientation (XYZAB). The location of base and effector
joints is defined by HAL parameters. The forward kinematics iteration is controlled by HAL pins.

pentakins.base.N.x
pentakins.base.N.y
pentakins.base.N.z
pentakins.effector.N.r
pentakins.effector.N.z
Parameters describing the Nth effector joint's radius and axial position.
pentakins.convergence-criterion
Minimum error value that ends iterations with converged solution.
pentakins.limit-iterations
Limit of iterations, if exceeded iterations stop with no convergence.
pentakins.max-error
Maximum error value, if exceeded iterations stop with no convergence.
pentakins.last-iterations
Number of iterations spent for the last forward kinematics solution.
pentakins.max-iterations
Maximum number of iterations spent for a converged solution during current session.
pentakins.tool-offset
TCP offset from effector origin along Z to implement RTCP function. To avoid joints jump change
tool offset only when the platform is not tilted.

pumakins - kinematics for puma typed robots
Kinematics for a puma-style robot with 6 joints

pumakins.A2
pumakins.A3
pumakins.D3
pumakins.D4
Describe the geometry of the robot

rosekins - kinematics for a rose engine using
a transverse, longitudinal, and rotary joint (3 joints)

rotarydeltakins - kinematics for a rotary delta machine
Rotary delta robot (3 Joints)

rotatekins - Rotated Kinematics
The X and Y axes are rotated 45 degrees compared to the joints 0 and 1.

scarakins - kinematics for SCARA-type robots
(See switchkins documentation for more info)

scarakins.D1
Vertical distance from the ground plane to the center of the inner arm.

scarakins.D2
Horizontal distance between joint[0] axis and joint[1] axis, ie. the length of the inner arm.

scarakins.D3
Vertical distance from the center of the inner arm to the center of the outer arm. May be
positive or negative depending on the structure of the robot.

scarakins.D4
Horizontal distance between joint[1] axis and joint[2] axis, ie. the length of the outer arm.

scarakins.D5
Vertical distance from the end effector to the tooltip. Positive means the tooltip is lower than
the end effector, and is the normal case.

scarakins.D6
Horizontal distance from the centerline of the end effector (and the joints 2 and 3 axis) and the
tooltip. Zero means the tooltip is on the centerline. Non-zero values should be positive, if
negative they introduce a 180 degree offset on the value of joint[3].

tripodkins - Tripod Kinematics
The joints represent the distance of the controlled point from three predefined locations (the motors),
giving three degrees of freedom in position (XYZ)

tripodkins.Bx
tripodkins.Cx
tripodkins.Cy
The location of the three motors is (0,0), (Bx,0), and (Cx,Cy)

xyzac-trt-kins - 5 Axis mill (Table Rotary/Tilting)
Tilting table (A) and horizontal rotary mounted to table (C axis) (5 Joints 0:x,1:y,2:z,3:a,4:c) with
provisions to switch between xyzac and trivkins kinematic types. The joint mapping can be altered with
the coordinates parameter in the same way as supported by trivkins. (See switchkins documentation for
more info)

xyzbc-trt-kins - 5 Axis mill (Table Rotary/Tilting)
(5 Joints 0:x,1:y,2:z,3:b,4:c) with provisions to switch between xyzbc and trivkins kinematic types. The
joint mapping can be altered with the coordinates parameter in the same way as supported by trivkins.
(See switchkins documentation for more info)

5axiskins - 5 Axis bridge mill
XYZBCW -- the W coordinate values (typically used for tool motion) are incorporated into XYZ positioning.
(Only 5 joints are needed by the kinematics module but an additional joint is needed to display W
values). (See switchkins documentation for more info)

By default, 5axiskins uses coordinates XYZBCW assigned consecutively to joints 0..5. The module
coordinates parameter may be used to assign multiple joints to an axis letter and/or to assign joints to
additional coordinates A,U,V with a one-to-one correspondence to the assigned joints. Example: XYZBCWYV
(8 joints total numbered 0..7) uses two joints for Y (joints 1,6) and adds an additional coordinate V
that has a one-to-one relation to joint 7.

Note: These kinematics may be used with the vismach 5axisgui providing that the joint-letter assignments
agree with the default ordering expected by it (XYZBCW -> joints 0..5)

NAME

SYNOPSIS

DESCRIPTION

SEE ALSO