Brief analysis of the principles of use of robot positioning grippers

Workstation background: Grab the workpiece with a gripper, put the gripper in the workstation, and then fix the robot gripper with the fixture. The robot disengages from the gripper, and other robots start welding. After the work is completed, the robot grabs the gripper, leaves the workstation, and then grabs the workpiece.

The valve pilot is controlled by US2:

Gas circuit design

In order for the tool to automatically connect to Stäubli, the following procedure must be followed.

1 Check whether the docking system is free (tool not docked) 2 Check whether there is a tool in the storage station (check all storage stations in the robot cell) 3 If there is a tool, open the storage station cover 4 Check whether the storage station cover is open 5 Move to the starting point of the gun changer (this position depends on the type of MPS), move to the Y distance above the docking position 6 Start the guide element in the direction of the MPS at the intermediate point of the tool change (this position depends on the MPS used), dimension X above the docking position 7 The robot stops moving 8 Unlock the MPS (MPS unlock output is "high") 9 Query the docking signal (check whether all docking signals are in the normal state) 10 Start the docking point in the direction of the MPS guide element 11 Query the blocking signal investigation (check whether all blocking signals are in the normal state) 12 Block the MPS (MPS unlock signal output is "low") 13 Query the blocking tool signal and tool code 14 Move away from the docking point in the direction of the storage guide (dimension Z) 15 Check whether the tool has been removed from the storage station 16 Leave the storage station and close the storage station cover if necessary

Locking device

Step 1: • The robot side and the tool side are separated (loose) • The piston is held in the locked position by a spring • The steel ball is pressed outwards in the locked position

Locking device

• The robot side and tool side are separated (loose)

• Release the air hole to let in compressed air to increase pressure, and the piston moves in the direction of the arrow

• The force of the steel ball is released (it can move in the direction of the arrow)

Locking device Step 3: • The robot side and the tool side are in engagement • The piston is in the released position due to the compressed air • The force of the steel ball is released (it can move in the direction of the arrow)

Locking device Step 4: • The robot side and the tool side are in the engaged state • Compressed air is introduced into the locking air hole to increase pressure, and the piston moves in the direction of the arrow • The steel ball moves in the direction of the arrow under pressure and is pressed into the steel ball groove on the tool side

The principles for using the positioning gripper are as follows: 1. When the robot grabs the tool, the robot drives the gun changer to move toward the tool, and SS1 is activated first. 2. When the gun changer on the robot side continues to move toward the gun changer on the tool side, SS2 is activated, and SS1 remains activated. 3. Continue to move in the original direction, SS1 exits the activated state, and SS2 remains activated at this time. 4. The two ohm safety switches remain in the ○3 state until the two sides of the gun changer fit in place, and then lock. 5. The robot carries the tool and leaves the docking station, SS2 exits the activated state, and SS1 remains in an inactivated state. 6. When the robot carries the tool and works normally, keep both ohm safety switches inactivated.

Difficulty of fault:

Since the combined control of the gripper fixture and PLC requires closing the safety door to control the fixture to achieve sequential control, it is difficult for us to observe the first time a fault occurs and we can only observe the robot IO to make a judgment.

There is no fault when the robot grabs the gripper, only when the robot disengages the gripper will it report an error without E540.

Cause Analysis:

analyze:

--------Lower the gripper trajectory:

PTP VB=100% VE=100% C=100% RobWzg=1 Base=1 SPSTrig=0[1/100s] P

-- Undock Greifer Position – The position where the gripper is lowered

LIN VB=200[mm/s] VE=0% ACC=100% RobWzg=1Base=1 SPSTrig=5[1/100s] P

1: FB PSPS = ON

2: A23 = OFF

3: WAS UP TO E58

4: -- (A75) Tool release 6 PF2V3112020 WZ1Z33-34 Control F/R --

5: A75 = EIN ----- After the robot is in place, PLC and fixture can be issued

6: -- (E75) Position release 6MS2V2 112016 Part Insert exit --

7: WARTE BIS E75 -----PLC allows the robot to leave the fault

8: A75 = AUS ----- Turn off the robot to allow the PLC to close the fixture fault.

9: TECH3_ PN-Docken ID-Nr =145Abschalten EIN off

10: WARTE ( EIN ) ZEIT 5 [1/10Sek] Waiting time

11: WAIT UNTIL E23

12: A23 = ON

13: SPSMAKRO422 = !E540 Quick-change head reset

14: SPSMAKRO420 = EIN Open the quick-change head to output A539, ​​and disengage the quick-change head.

15: FB PSPS = E42 & E46 & E58 & E75 & E80 & M3

---When the unlock signal A539 is issued to open the quick-change head, the safety block is not reached by the safety module, so the quick-change head reports an error again without E540.

"Unlock" signal failure

In the standard version, if the "unlock" signal is set and the safety switch is not activated, this state is recognized as a fault and H5 lights up red. After a delay of 2 seconds, H6 lights up red.

-- After Undock Greifer Position – After Undock Greifer Position

LIN VB=150[mm/s] VE=0% ACC=100% RobWzg=32 Base=1 SPSTrig=5[1/100s] P

1: FB PSPS = ON

2: A23 = OFF

3: WAIT UNTIL E23

4: A23 = ON

5: A539 = AUS ---Close the disconnect valve control after reaching the disconnect position.

6: FB PSPS = E42 & E46 & E58 & E75 & E80 & M3

PTP VB=100% VE=0% ACC=100% RobWzg=32 Base=1 SPSTrig=0[1/100s] P

--------Lower the gripper trajectory:

PTP VB=100% VE=100% ACC=100% RobWzg=32 Base=1 SPSTrig=0[1/100s] P

--Befe Dock Greifer Position – Front Dock Greifer Position

LIN VB=100[mm/s] VE=0% ACC=100% RobWzg=32 Base=1 SPSTrig=5[1/100s] P

1: FB PSPS = ON

2: A23 = OFF

3: WAIT UNTIL E23

4: A23 = ON

5: SPSMAKRO422 = !E540 ----- Fault reset

6: A539 = EIN -----Open the quick-change head unlock

7: WAIT UNTIL !E538 & E539 &E540

8: FB PSPS = E42 & E46 & E58& E74 & E80 & !E538 & E539 & M30

-- Dock Greifer Position

LIN VB=100[mm/s] VE=0% ACC=100% RobWzg=32Base=1 SPSTrig=5[1/100s] P

1: FB PSPS = ON

2: SPSMAKRO422 = !E540 ----- Fault reset

3: SPSMAKRO421 = EIN -----Open the quick-change head and lock it

4: A23 = OFF

5: TECH3_ PN-Docken ID-Nr =145Zuschalten EIN -----Gripper net

6: WAIT (ON) TIME 1 [1/10sec]

7: A75 = EIN -----Robot allows PLC fixture to open

8: WARTE BIS E73 -----Waiting for PLC to release

9: A75 = AUS ------ Turn off the robot and allow the PLC fixture to open

10: F1 = ON

11: F3 = ON

12: SPSMAKRO342 = EIN Open jaws

13: SPSMAKRO340 = EIN shut-off valve

14: WAIT UNTIL M31 & M35

15: F2 = ON

16: F4 = ON

17: SPSMAKRO342 = EIN Open jaws

18: SPSMAKRO340 = EIN shut-off valve

19: WAIT UNTIL M31 & M33 & M35 & M37 & M81

20: WAIT UNTIL E23

21: A23 = ON

22: FB PSPS = E42 & E46 &E73 & E80 & M30 & M31 & M33 & M35 & M37 & M81

----------When the robot is grabbing the object - the safety switch of the robot's quick-change head can no longer detect the safety block, and E540 does not start to automatically close the locking valve. At this time, the object can be grabbed because of E538.

PTP VB=100% VE=0% ACC=100% RobWzg=1 Base=1SPSTrig=5[1/100s] P

measure:

Check the robot's gripper track. If the track is deviated, the gripper's placement plane is tilted, and optimize the robot's gripper track.

Optimize the robot's lifting trajectory.

Check that there is no problem with the quick-change head connection.

Analyze the program and analyze the disconnection sequence.

The safety baffle is a little small, so adjust the angle of the safety switch detection baffle to eliminate the fault.

Safety detection switch

Safety stop

Detection range of safety detection switch and safety baffle:

Solution:

---------------Safety switch failure--------------

Safety switch failure: No E540

If the safety switch fails, the module will output a fault signal and indicate this by lighting up the red LED H3.

------------------- "Unlock" signal failure -------------------

"Unlock" signal failure

If the "unlock" signal is set in the standard version and the safety switch is not activated, this state is detected as a fault and LED H5 lights up red, and after a delay of 2 seconds H6 lights up red.

---------------------Fault Detection-----------------

Detection of electrical faults

If an electrical fault occurs in US1, LEDs H4 and H5 will light up red at the same time

----------------------Pressure test----------------------

Pressure detection

LED H2 will indicate whether there is pressure in the locking channel (pressure switch D1). This LED should be green outside the docking station (safety switch not activated). If there is no pressure outside the docking station or the pressure switch is faulty, LED H2 will go out and LED H5 will be red.

Common faults:

Solenoid valve failure.

Phenomenon:

Unable to switch the gas line, the solenoid valve is broken.

reason:

1. Forget to reset the solenoid valve after manually switching it.

2. The solenoid valve is cracked, interfered with, and the protective cover is not in place.

Treatment method:

1. Reset the solenoid valve.

2. Replace spare parts.

3. Adjust the position of the protective cover or replace the protective cover.