Hand-E Adaptive Gripper control delay with UR robots

macale

Greetings,

During my work with multiple setups of UR robots with Hand-E Adaptive Grippers I have observed that the URCap commands introduces delay in comparison to controlling the gripper directly through modbus converter.

The setup with the Hand-E gripper connected via modbus to the UR5e robot is using URScript standard commands to set and read registers from the gripper via the converter. It's working fast and robust without any delays.

The other setups consisted of UR5+Hand-E and UR5e+Hand-E are using serial port communication and URCap plug-in to control the gripper with following code:

def gripper_activate():
        textmsg("Gripper activation")
        rq_reset()
        rq_activate_and_wait()
        rq_set_speed_norm(100)
        rq_set_force_norm(50)
end

def gripper_set(target):
        if (0 <= target and target <= 50):
            rq_move_and_wait_mm(target)

            textmsg("gripper executing: ", target)
            textmsg("gripper position after move: ", rq_current_pos_mm())
            textmsg("gripper objectdetected: ", rq_is_object_detected())
            rq_print_gripper_driver_state()

            if(rq_is_object_detected() or rq_is_motion_complete()):
                textmsg("SUCCESS")
            else:
                textmsg("ERR_FAILED")
            end
        else:
            textmsg("ERR_OUT_OF_RANGE, target=", target)
        end
end

The execution of "rq_move_and_wait_mm()" command can be seen immediately on the gripper, but the script hangs on it for longer period of time (about 1 or 2s).

Investigation of this behavior showed that the the gripper current position readed from the RTDE protocol is being set to a constant value during the command execution and it takes time to be refreshed. Moreover, controlling the gripper from the teach pendant URCap menu doesn't show any delay at all.

Is there a better way to control the gripper via URCap Robotiq plug-in without described delay?

The software versions on mentioned setups are:

• UR5e+Hand-E+Modbus TCP - UR 5.6.0
• UR5+Hand-E - UR 3.13.0, Robotiq URCap UCG-1.5.1
• UR5e+Hand-E - UR 5.7.0, Robotiq URCap UCG-1.6.0.4
  

Best regards.