Scripting RobotApi

Part of the Scripting API. RobotApi wraps one Robot object.

from freecad.robotics.App.rbt_api import get_robot
rob = get_robot()

Read the structure

Member	Value
rob.n_joints	Number of joints
rob.joint_types	Joint types of the kinematic chain
rob.limits	List of (min, max) for each joint
rob.max_speeds	Maximum speed of each joint
rob.dof_mask	Movable joints as a list of booleans
rob.doc, rob.assembly	The document and the wrapped assembly

for i, (lo, hi) in enumerate(rob.limits):
    print(f"J{i+1}: {lo:g} .. {hi:g}")

Move the joints

Member	Function
rob.q	Joint values. Read and write. Degrees for revolute joints, millimeters for sliders
rob.set_q(q, clamp=False, preview=False)	Set all joints. clamp=True keeps the values in the limits
rob.set_joint(i, value)	Set one joint
rob.jog(q)	Preview only. A recompute sets the pose back
rob.check_limits(q=None)	Empty text when the values are in the limits. Else the violation text

rob.q = [0, -30, 45, 0, 60, 0]

rob.set_joint(0, 15)               # J1 to 15 deg
rob.set_q([0, -90, 90, 0, 0, 0], clamp=True)

msg = rob.check_limits([0, -200, 0, 0, 0, 0])
if msg:
    print(msg)                     # the violation text

Home and zero

Member	Function
rob.home	The saved home pose
rob.go_home()	Move all joints to the home pose
rob.save_home()	Save the current pose as the home pose
rob.save_zero()	Make the current pose the zero pose ("mastering")

rob.q = [0, -30, 45, 0, 60, 0]
rob.save_home()
rob.q = [90, 0, 0, 0, 0, 0]
rob.go_home()                      # back to the saved pose

Forward and inverse kinematics

Member	Function
rob.tcp	World TCP placement now (flange when no tool)
rob.fk(q=None)	World TCP for joint values q
rob.ik(target, q_seed=None)	Joint values for a target placement. None when there is no solution
rob.move_to(target)	Solve IK and move the joints

tgt = rob.tcp.copy()
tgt.Base.z -= 50                   # 50 mm down
rob.move_to(tgt)

q = rob.ik(tgt)                    # solve only, no movement
if q is None:
    print("no IK solution")

Base, tool, backend

Member	Function
rob.base	The robot's BasePlacement. Write it to move the full robot
rob.tool, rob.tools	The active tool and the list of all tools
rob.add_tool(name, shape_file=None)	Make a new active tool
rob.kinematics_lib	The IK backend name. See Kinematics

import FreeCAD as App

rob.base = App.Placement(App.Vector(500, 0, 0), App.Rotation())
tool = rob.add_tool("Gripper", shape_file=r"C:\tools\gripper.FCStd")
rob.kinematics_lib = "numpy_dls"

Escape hatches

Member	Function
rob.recompute()	Recompute the assembly and the tool
rob.invalidate_cache()	Discard the cached chain and backend
rob.fpo	The raw FeaturePython object

Next: TrajectoryApi