Move a Gantry

You have a gantry (a Cartesian robot with linear axes) and need to move it to specific positions. You can either control axes directly with the gantry API or use the motion service for planned, collision-aware movement.

Direct axis control

Use the gantry component API for simple, direct movements.

from viam.components.gantry import Gantry

gantry = Gantry.from_robot(machine, "my-gantry")

# Read current position (mm for each axis)
positions = await gantry.get_position()
print(f"Current positions: {positions}")

# Read axis lengths
lengths = await gantry.get_lengths()
print(f"Axis lengths: {lengths}")

# Move to a specific position
await gantry.move_to_position(positions=[200, 300, 100])

import "go.viam.com/rdk/components/gantry"

myGantry, err := gantry.FromRobot(machine, "my-gantry")
if err != nil {
    logger.Fatal(err)
}

positions, err := myGantry.Position(ctx, nil)
if err != nil {
    logger.Fatal(err)
}
fmt.Printf("Current positions: %v\n", positions)

lengths, err := myGantry.Lengths(ctx, nil)
if err != nil {
    logger.Fatal(err)
}
fmt.Printf("Axis lengths: %v\n", lengths)

err = myGantry.MoveToPosition(ctx, []float64{200, 300, 100}, nil)
if err != nil {
    logger.Fatal(err)
}

Motion-planned movement

For complex paths or collision avoidance, use the motion service.

from viam.services.motion import MotionClient
from viam.proto.common import PoseInFrame, Pose

motion_service = MotionClient.from_robot(machine, "builtin")

destination = PoseInFrame(
    reference_frame="world",
    pose=Pose(x=200, y=300, z=100, o_x=0, o_y=0, o_z=1, theta=0)
)

await motion_service.move(
    component_name="my-gantry",
    destination=destination,
)

destination := referenceframe.NewPoseInFrame("world",
    spatialmath.NewPose(
        r3.Vector{X: 200, Y: 300, Z: 100},
        &spatialmath.OrientationVectorDegrees{OX: 0, OY: 0, OZ: 1, Theta: 0},
    ))

_, err = motionService.Move(ctx, motion.MoveReq{
    ComponentName: "my-gantry",
    Destination:   destination,
})

What’s Next