Rather than exporting HAL pins and functions, these components provide the forward and inverse kinematics
definitions for LinuxCNC.
trivkins-generalizedtrivialkinematics
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 trivkinscoordinates=xyz
Assigns: x==joint0, y==joint1, z==joint2
Example: loadrt trivkinscoordinates=xz
Assigns: x==joint0, z==joint1
Example: loadrt trivkinscoordinates=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 trivkinscoordinates=xyzkinstype=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 HomingConfiguration.
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 jointmode. 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 jointmode. 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-CoreXYKinematics
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-HexapodKinematics
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.xgenhexkins.base.N.ygenhexkins.base.N.zgenhexkins.platform.N.xgenhexkins.platform.N.ygenhexkins.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.xgenhexkins.base-n.N.ygenhexkins.base-n.N.zgenhexkins.platform-n.N.xgenhexkins.platform-n.N.ygenhexkins.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-generalizedserialkinematics
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-Ngenserkins.ALPHA-Ngenserkins.D-N
Parameters describing the Nth joint's geometry.
maxkins-5-axiskinematicsexample
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-PentapodKinematics
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.xpentakins.base.N.ypentakins.base.N.zpentakins.effector.N.rpentakins.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-kinematicsforpumatypedrobots
Kinematics for a puma-style robot with 6 joints
pumakins.A2pumakins.A3pumakins.D3pumakins.D4
Describe the geometry of the robot
rosekins-kinematicsforaroseengineusing
a transverse, longitudinal, and rotary joint (3 joints)
rotarydeltakins-kinematicsforarotarydeltamachine
Rotary delta robot (3 Joints)
rotatekins-RotatedKinematics
The X and Y axes are rotated 45 degrees compared to the joints 0 and 1.
scarakins-kinematicsforSCARA-typerobots
(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-TripodKinematics
The joints represent the distance of the controlled point from three predefined locations (the motors),
giving three degrees of freedom in position (XYZ)
tripodkins.Bxtripodkins.Cxtripodkins.Cy
The location of the three motors is (0,0), (Bx,0), and (Cx,Cy)
xyzac-trt-kins-5Axismill(TableRotary/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-5Axismill(TableRotary/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-5Axisbridgemill
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)
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