I’m programming UR3e to perform stirring/rinsing motions. For path, I have a script to generate movel waypoints. Inside script, I have a loop where I increment circular radius, sway distance, tilt angle, and Z amplitude to generate desired trajectory using movel waypoints. I have no issues with the trajectory, however the robot TCP motion is very jerky. It feels like a stop n go kind of motion. At high acceleration, I can feel the vibrations on the base plate.
What can I do to smoothen this motion? I’m trying to mimic the fluidity of human hands performing stirring/rinsing motions. I have tried reducing acceleration, reduce blend radius in movel, and reduce angle increment but it hasn’t helped. I’d appreciate any advice if there’s a different script directory command that can help me achieve this or any other method. Thanks!
Here’s the script:
def function():
center = get_actual_tcp_pose() # start pose
radius = 0.01 # circle radius in meters
v_circ = 0.15 * 2 # speed (m/s) during circles
a_circ = 1.2 * 2 # accel for circle motions
z_amp = 0.01 * 7 # vertical oscillation amplitude (m)
tilt_amp = 0.18 # radians (~10.3°) max tilt (X/Y axes)
sway_amp = 0.012 # side-to-side sway amplitude (m)
tilt_z_amp = 3.14159/2 # radians (±90°) tilt around Z
duration_s = 30 # time duration for process
t_start = time().sec
while ((time().sec - t_start) < duration_s):
angle = 0
while (angle < 6.28): # loop through 0 → 2π
# vertical up/down oscillation
z_offset = z_amp * sin(angle)
# side-to-side sway added to X path
dx = radius*cos(angle) + sway_amp*sin(2*angle)
dy = radius*sin(angle)
# small tilt oscillations
tilt_x = tilt_amp * sin(angle) # around X-axis
tilt_y = tilt_amp * cos(angle) # around Y-axis
tilt_z = tilt_z_amp * sin(angle) # around Z-axis, swings ±90°
# build pose offset
offset = p[dx, dy, z_offset, tilt_x, tilt_y, tilt_z]
target = pose_trans(center, offset)
movel(target, a=a_circ, v=v_circ, r=0.001)
angle = angle + 0.3
# Stop if total time exceeded mid-loop
if ((time().sec - t_start) >= duration_s):
break
end
end
end
stopl(2.0)
end
