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Kinematics

Forward Kinematics

Compute the TCP pose from joint angles.

pose = arm.forward_kinematics([0.0, 0.0, 0.0, 1.57, 0.0, 0.0, 0.0])
print(f"TCP: ({pose.x:.3f}, {pose.y:.3f}, {pose.z:.3f})")

Parameter:

  • angles: 7 joint angles in radians, type list[float]

Return value:

  • Pose: TCP pose

Inverse Kinematics

Solve joint angles from a TCP pose.

from realhand import Pose

target = Pose(x=0.0, y=0.33, z=-0.25, rx=1.85, ry=0.0, rz=-1.57)
angles = arm.inverse_kinematics(target)
print(f"Joint angles: {angles}")

Parameters:

  • pose: Target TCP pose, type Pose
  • current_angles: Initial IK guess for joint angles, type list[float] | None; when None, the SDK reads the motors

Return value:

  • list[float]: 7 joint angles in radians

Joint Limits

# Read the current joint limits
limits = arm.get_joint_limits()
print(limits)  # [(lower0, upper0), (lower1, upper1), ...]

# Set custom joint limits
arm.set_joint_limits([(-1.0, 1.0)] * 7)