Deliver a payload between two pads without touching a tall protected column (dual Panda)

Two Franka Emika Panda arms (7 joints each, with a parallel two-finger hand whose fingers open to 8 cm; the hand is about 20 cm wide along the finger axis) are mounted side by side at the back edge of a 1.6 m x 0.94 m desk, both reaching forward toward you. The "left" arm is the one at negative x (on the left in the front camera view), the "right" arm the one at positive x. This is a MuJoCo physics simulation with the MuJoCo Menagerie robot models: every object is a free rigid body that moves only through contact and friction (nothing is attached or teleported), so a loose grip, a fast swing or a collision can drop or knock things over. World frame in metres: +x to the right, +y toward the robots (the back of the desk), +z up; the desk top is z = 0.

Goal: A pawn-shaped payload (6 cm tall, 2.6 cm base) stands on the teal source pad on the left. Move it to the teal delivery pad and stand it upright. A tall red column (6 cm across, 60 cm tall, too tall to pass over) stands between the two pads. It is protected: neither arm, nor the payload, may touch it at any time.

Success: The payload's base centre is within 15 mm of delivery_pad_center, it rests on the pad (within 4 mm of z = 0.002), is tilted at most 10 degrees, released and at rest; and nothing but the desk ever touched the column. Success is judged by the episode server from the physical state after you call robo done and the robots have held still for about 10 steps (0.5 s). "Released" means neither arm touches the object; "at rest" means it moves slower than 1 cm/s.

Goal fields in robo observe: source_pad_center, delivery_pad_center, pad_half_size, column_center_xy, column_radius and column_height.

Controls. You drive the left arm only (the other arm stays parked). robo act DX DY DZ GRIP moves the arm's commanded gripper target by DX, DY, DZ times 2 cm per step along world x, y, z (each in [-1, 1], so 0.25 = 5 mm); GRIP 0 keeps the fingers as they are, any positive value closes them, and a negative value -f opens them to fraction f of full width (-1 fully open, -0.4 = 40 % open). One step is 50 ms of simulated time. Inverse kinematics turns the target into joint commands; the gripper always points straight down. robo move-to X Y Z and robo grip G drive the same arm (move-to stops within --tol metres of the point, default 0.01).

Observation. robo observe reports, for each arm you drive, hand_pos (the measured point between the fingertips), hand_target (where the arm is being driven; it can run up to 5 cm ahead of the hand, which then catches up), gripper_open (0 closed .. 1 fully open) and touching (task objects in contact with that arm); for every task object <name>_pos (the centre of the object's base, where it touches the surface below), <name>_tilt_deg (tilt from upright) and <name>_yaw_deg; plus the goal fields listed above. robo observe --image saves a picture from the front camera (--camera overhead looks straight down with +y at the top of the picture; --camera overview is a far corner view).

The arm's links run from its base at the back of the desk (y = 0.30) forward and down to the hand; the Panda hand is about 20 cm wide along the finger axis (world y at yaw 0).

The step budget is 1000 steps (50 s of simulated time).