Move Safe

rstuart

I am working on my first UR project. I need the ability to read joint positions and have the robot use thise positions to move to a safe start point as to not collide with anything. Can someone help me with the best way of doing this? Thanks!

mhowe

1. Read current position, save in variable
2. Define new pose variable

The example is having the robot only change in the Z direction.

BeforeStartSequence

     cp = get_actual_tcp_pose()

     z = cp[2]

     safe_pos = p[cp[0], cp[1], 0.4, cp[3], cp[4], cp[5]]

     Wait 1

     MoveL

          safe_pos

Robot Program

     Halt

JopsonL

The way i created a homing program was by setting a variable to every way point and then setting the variable to one when the robot moves to that certain way point, off this i could write a subprogram which would move the robot home using way points. Don't forget to set the variable back to zero after each way point. 

If you have your home position in before start then change it to a relative position instead of fixed position. The robot would not home unless this was set, unsure why. 

Set these as installation variables. 
RobotTracker
currentSubProg

Below is a portion of the program which is relevant to the homing of the robot. 

 Program

   BeforeStart

     Home_Tracker≔'Is the robot at home?'

     If Home_Tracker ≟  True 

       RobotTracker≔1                      

       currentSubProg≔1                

     MoveJ

       Home_position                         //this is the way point which is set to fixed position 

 Robot Program

     If currentSubProg ≟ 1

       Call part_pick

       Call move_to_tool

       Call Load_unload_part

       Call move_to_conveyor

       Call deposit_on_conveyor

       If Stop_request≥1 and ppcount≟0

         Set Conveyor_Forwd=Off

         Halt

     ElseIf currentSubProg ≟ 2

       Call Homing_Function

   Event Home_Button ≟  True  

     currentSubProg≔2

     Wait: 5.0

     sync()

 Homing_Function

     'Homing from Part Pick'

     If RobotTracker≟1

       MoveJ

         Above_pallet

         Home_position_1

         RobotTracker≔0

         StopVar≔1

     'Homing from Move To Tool'

     If RobotTracker≟2

       MoveJ

         Ready_to_load

         Clear_door_pos2

         Clear_door_pos1

         Home_position_2

         RobotTracker≔0

         StopVar≔1

     ElseIf RobotTracker≟3

       MoveJ

         Clear_door_pos2

         Clear_door_pos1

         Home_position_3

         RobotTracker≔0

         StopVar≔1
currentSubProg≔1 

If StopVar≟1

        StopVar≔0

        Halt

Hope this makes sense. 

rstuart

I found a tutorial on the UR website. https://www.universal-robots.com/how-tos-and-faqs/how-to/ur-how-tos/creating-a-safe-home-routine-19477/