Carton Pick & Place
HITBOT S922 · RealSense D415 · with Nishant Rana
A six-axis HITBOT arm picks up a carton it was never told the position of. There are no fixtures, no hard-coded coordinates and no ROS: the whole stack is Python. I built it at XP Robotics with Nishant Rana.
one depth frame to a pick
- An Intel RealSense D415 on the wrist captures one aligned depth frame, which becomes a point cloud.
- The cloud is downsampled and the table plane is fitted. Anything standing a few centimetres above it is a candidate.
- DBSCAN groups the candidates into objects, and each one gets an oriented top face and a size.
- If a top face is too small for the four suction pads to seal on, the arm leaves it alone. Of what's left, it takes the nearest.
- Hand-eye calibration, an AX = XB solve against a ChArUco board, moves that pose from the camera's frame into the robot's base frame.
- The pick is three Cartesian moves: hover, contact and lift. Each is split into short waypoints with an inverse-kinematics solution at every step, and the arm stops if the solver flips configuration partway through.
The descent goes about 13 mm past the expected contact point so the suction bellows compress. At 3 mm, the pads were barely touching the lid.
Then: vacuum on, a short dwell, lift, swing the base, descend, release, and back home. The carton lands at a PLC-controlled station, the same hand-off it would make on a real line.
Every motion script has a dry-run mode, and a hover test parks the pads a set distance above the carton before anything touches it. RealSense left a comment on the LinkedIn post.