Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
How to rotate object at the edge of conveyor?
Hi all Good Morning :), 

So i've been doing my conveyor project using RunConveyor script from "Example-06.e-Conveyor with 2 UR robots" on the library. The object is moving but i want the object to rotate Y=-45 degrees when the object reach the edge.  I have been editing the section where "objects that reached the end of the conveyor and were not picked" to ([0,0,0,0,-45,0]) but it turns out the object won't rotate. 

This is the script:


# Speed of movement in MM/S with respect to the conveyor coordinates:
MOVE_SPEED_MMS = [0,50,0]

# Define workspace of the conveyor to pick the objects:
CONV_SZ_Z_MIN = -200
CONV_SZ_Z_MAX = +500

# Move objects that reached the end of the conveyor and were not picked:
FALLEN_OBJECTS = ([0,0,0,0,-45,0])

# Get the conveyor item and reference for work space:
conv_reference = conv.Parent()
poseconv = conv_reference.PoseAbs()

# One second in real life means 1 second of simulation. The simulation speed is taken from the station

def is_inside_conveyor(pose):
    """Checks if a pose is inside the conveyor workspace"""
    pos = pose.Pos()
    if pos[0] > CONV_SZ_X_MIN and pos[0] < CONV_SZ_X_MAX and pos[1] > CONV_SZ_Y_MIN and pos[1] < CONV_SZ_Y_MAX and pos[2] > CONV_SZ_Z_MIN and pos[2] < CONV_SZ_Z_MAX:
        return True
    return False

def conveyor_move_object(pose, delta_time):
    """Moves the object pose through the conveyor depending on the time and speed"""
    delta_mm = mult3(MOVE_SPEED_MMS, delta_time)
    newpose = transl(delta_mm)*pose
    return newpose

# Get all objects (string list)
all_objects = RDK.ItemList(ITEM_TYPE_OBJECT, True)

# Convert object list into item pointers (faster)
# Also filter the list to take into account pickable objects only
objects = []
objects_name = []
objects_active = []
for i in range(len(all_objects)):
    if all_objects[i].count(PICKABLE_OBJECTS_KEYWORD) > 0:

# The number of objects that can go in the conveyor
nobjects = len(objects)

# Infinite loop to simulate the conveyor behavior
current_time = 0
time_last = toc()
while True:
    # First: Look for objects that are not in the conveyor but are in the conveyor workspace
    for i in range(nobjects):
        obj_i = objects[i]
        # Skip if the object is already in the conveyor
        if objects_active[i]:
        # Check if the object has already been taken by a tool. If so, do not take it in the conveyor
        if obj_i.Parent().Type() == ITEM_TYPE_TOOL:

        # Check if the object is within the conveyor work area
        posei = obj_i.PoseAbs()
        poseirel = invH(poseconv)*posei
        if is_inside_conveyor(poseirel):
            # take the object
            print('Adding object %s to the conveyor' % objects_name[i])
            objects_active[i] = True

    # Second step: Update the position of every object in the conveyor
    SIMULATION_SPEED = RDK.SimulationSpeed()
    time_current = toc()
    time_delta = time_current - time_last
    time_last = time_current
    current_time = current_time + time_delta*SIMULATION_SPEED

    # Make a list of objects with their matching positions to update
    obj_items = []
    obj_poses_abs = []
    for i in range(nobjects):
        obj_i = objects[i]

        # Check if the object has been picked from the conveyor
        if objects_active[i] and not obj_i.Parent().equals(conv):
            objects_active[i] = False
            print('Object %s was picked from the conveyor' % objects_name[i])

        # Skip update for objects that are not in the conveyor
        if not objects_active[i]:

        # Update the position of the object
        posei = invH(poseconv)*obj_i.PoseAbs()
        newposei = conveyor_move_object(posei, time_delta*SIMULATION_SPEED)
        if not is_inside_conveyor(newposei):
            print('Warning!! Object %s fell from the conveyor at %.1f seconds after simulation started' % (objects_name[i], current_time))
            #raise Exception('Object %s was not picked from the conveyor!' % objects_name[i])
            newposei = transl(FALLEN_OBJECTS)*newposei
            objects_active[i] = False
        #obj_i.setPose(newposei) # this will provoke a refresh (can be slow)

    # Update the object positions
    RDK.setPosesAbs(obj_items, obj_poses_abs)

    # Take a break...

so, this is the result that i get now:

and also this is my expected result:

i hope somebody will help me to solve this.

Thanks in advance.

Hi Rev,

Take a look at this example.
If that doesnt help, maybe you can share the station with me so I can have a closer look at it?


Attached Files
.rdk   Conveyor example.rdk (Size: 151.47 KB / Downloads: 240)
(03-05-2021, 03:19 PM)Olivier Wrote: Hi Rev,

Take a look at this example.
If that doesnt help, maybe you can share the station with me so I can have a closer look at it?


Hi Olivier,

Thank you for your help and sorry for the late response, i will try your example and also inform you my progress.


Users browsing this thread:
1 Guest(s)