UNIT V. Prepared by Dr.K.S.Badrinathan 2 IMPLEMENTATION AND ROBOT ECONOMICS

Transcription

1 UNIT V Prepared by Dr.K.S.Badrinathan 1 IMPLEMENTATION AND ROBOT ECONOMICS Automated Guided Vehicle System (AGVS), RGV Implementation of Robots in Industries Safety Considerations for Robot Operations Economic Analysis of Robots. Prepared by Dr.K.S.Badrinathan 2 1

2 Automated Guided Vehicle System (AGVS) An AGVS is a material handling system that uses independently operated, self propelled vehicles guided along defined pathways. Powered by on board batteries that allow many hours of operation (8 16 hours) Pathways are unobtrusive. Suitable for automating material handling in batch production & mixed model production Prepared by Dr.K.S.Badrinathan 3 Driverless trains Types of AGV vehicles Pallet trucks Unit load carriers Prepared by Dr.K.S.Badrinathan 4 2

3 Driverless AG train Prepared by Dr.K.S.Badrinathan 5 Driverless AG train A towing vehicle pulling one or more trailers to form a train To move heavy payloads over long distances in warehouses or factories with or without intermediate pickup and drop off points along the route Prepared by Dr.K.S.Badrinathan 6 3

4 Pallet Trucks Prepared by Dr.K.S.Badrinathan 7 Pallet trucks To move palletized loads along predetermined routes Human worker steers the truck and loads the pallet & puts it in is guidepath Forklift AGV can have vertical movement of its forks to reach loads on racks and shelves Prepared by Dr.K.S.Badrinathan 8 4

5 Unit Load Carriers Prepared by Dr.K.S.Badrinathan 9 Unit Load Carrier To move unit loads from one station to another Equipped for automatic loading and unloading of pallets or tote pans by means of : Powered rollers Moving belts Mechanized lift platforms Other devices built into the vehicle deck Prepared by Dr.K.S.Badrinathan 10 5

6 Applications of AGVS Driverless train operations Storage and distribution Assembly line applications FMS Prepared by Dr.K.S.Badrinathan 11 Vehicle Guidance Technology Method by which AGVS pathways are defined and vehicles are controlled to follow the pathways Technologies used: Imbedded guide wires Paint strips Self guided vehicles Prepared by Dr.K.S.Badrinathan 12 6

7 Wire Guided AGV Prepared by Dr.K.S.Badrinathan 13 Wire Guided AGV Electrical wires are placed in a small channel cut into the surface of the floor The channel is filled with cement to eliminate the discontinuity in the floor surface Guide wire is connected to a frequency generator, which emits low voltage, low current signal (1 15kHz) The induced magnetic field is followed by sensors on board each vehicle Prepared by Dr.K.S.Badrinathan 14 7

8 Paint Strip AGV Prepared by Dr.K.S.Badrinathan 15 Paint Strip AGV Vehicle uses an optical sensor system capable of tracking the paint Strips are taped, sprayed or painted on the floor Paint strips contain fluorescent particles that reflect an UV light source from the vehicle On board sensor detects the reflected light in the strip and controls the steering mechanism Prepared by Dr.K.S.Badrinathan 16 8

9 Self guided Vehicle Prepared by Dr.K.S.Badrinathan 17 Self guided Vehicle Operate without continuously defined pathways Uses a combination of dead reckoning and beacons located throughout the plant that can be identified by on board sensors Dead reckoning: capability of vehicle to follow a given route in the absence of a defined pathway in the floor Accomplished by computing the required number of wheel rotations Computations are performed by the vehicle s onboard computer Prepared by Dr.K.S.Badrinathan 18 9

10 Self guided Vehicle Beacons Positioning accuracy of dead reckoning decreases over long distances. It must be periodically verified by comparing the calculated position with one or more known positions. Beacons are used for this throughout the plant Barcoded or magnetic beacons Prepared by Dr.K.S.Badrinathan 19 RGV Rail Guided Vehicle Prepared by Dr.K.S.Badrinathan 20 10

11 Steps for Robot Implementation Initial familiarization with the technology Plant survey to identify potential applications Selection of the application Selection of the robot Detailed economic analysis & capital authorization Planning and engineering the installation installation Prepared by Dr.K.S.Badrinathan 21 Human Safety from Robots During programming of the robot During operation of the robot cell when humans work in the cell During maintenance of the robot Prepared by Dr.K.S.Badrinathan 22 11

12 Safety Sensors Sensors indicate conditions or events that are unsafe or potentially unsafe Sensors should protect humans and also the equipment in the cell Simple limit switches to sophisticated vision systems are needed to find intruders Care must be taken in the workcell design to anticipate all of the possible mishaps that might occur in the cell Prepared by Dr.K.S.Badrinathan 23 Levels of Safety Sensor Systems Level 1 Perimeter penetration detection Level 2 Intruder detection inside the workcell Level 3 Intruder detection in the immediate vicinity of the robot Prepared by Dr.K.S.Badrinathan 24 12

13 Levels of Safety Sensor Systems Prepared by Dr.K.S.Badrinathan 25 Safety Monitoring Strategies Complete shutdown of the robot upon detection of an intruder Activation of warning alarms Reduction in the speed of the robot to a safe level Directing the robot to move its arm away from the intruder to avoid collision Directing the robot to perform tasks in another region of the workcell away from the intruder Prepared by Dr.K.S.Badrinathan 26 13

14 Other Safety Measures Emergency stop buttons also called panic button are located on the main control panel and the robot teach pendant. Deadman switch is a trigger or toggle switch device located on the teach pendant. The switch is ON when it is pressed against a spring. When the pressure is removed the switch automatically goes to OFF mode. Prepared by Dr.K.S.Badrinathan 27 ECONOMIC ANALYSIS of ROBOTS Prepared by Dr.K.S.Badrinathan 28 14

15 Type of project Basic Data Required Cost of robot installation Production cycle time Savings & Benefits Prepared by Dr.K.S.Badrinathan 29 Types of Robot Installation New application no existing facility To replace the current method of operation; i.e. the manual method is replaced with robot Prepared by Dr.K.S.Badrinathan 30 15

16 Cost Data Required Investment cost Cost of robot: purchase price Engineering cost: planning and design Installation cost: labour & materials Special tooling: end effector, fixtures & tools Miscellaneous: other equipment needed Operating cost Direct labour: operator Indirect labour: supervisor, programming Maintenance: Utilities: electricity etc. Training: Prepared by Dr.K.S.Badrinathan 31 Life cycle of cash flow Prepared by Dr.K.S.Badrinathan 32 16

17 Methods of Economic Analysis Payback (or payback period) Method Equivalent Uniform Annual Cost (EUAC) Method Return On Investment (ROI) Method Prepared by Dr.K.S.Badrinathan 33 Payback Method Time required for the net accumulated cash flow to equal the initial investment in the project n = n = pay back period IC = Investment Cost NACF = Net Annual Cash Flow Prepared by Dr.K.S.Badrinathan 34 17

18 Payback Method Total Investment = Rs.30 lacs Anticipated revenue = Rs.18 lacs/year Operating cost = Rs.6 lacs/year NACF = Revenue operating cost = 18 6 = Rs.12 lacs/year n = = = 2.5 years Note: revenue is assumed to be same in all the years Prepared by Dr.K.S.Badrinathan 35 Disadvantage of Payback method Ignores the time value of money It does not consider the objective of the company to derive a certain minimum rate of return from its investments. Prepared by Dr.K.S.Badrinathan 36 18

19 Equivalent Uniform Annual Cost (EUAC) Method Converts all the present and future investments and cash flows into their equivalent uniform cash flows over the anticipated life of the project. Done by making use of the various interest factors associated with engineering economy calculations. A minimum attractive rate of return (MARR), 20 50, should be selected to decide whether a investment project should be funded. Prepared by Dr.K.S.Badrinathan 37 Equivalent Uniform Annual Cost (EUAC) Method Total Investment = Rs.30 lacs Anticipated revenue = Rs.18 lacs/year Operating cost = Rs.6 lacs/year Service life of robot = 5 years MARR = 30% EUAC = 30,00,000 (A/P,30%,5) +18,00,000 6,00,000 = 30,00,000 ( ) + 12,00,000 = 31,740 Note: if EUAC is positive, then project can be funded Prepared by Dr.K.S.Badrinathan 38 19

20 Return On Investment (ROI) Method Determines the rate of return (RoR) for the proposed project based on the estimated costs and revenues. This RoR is compared with the company s MARR to decide whether the investment is justified. Determination of RoR involves setting up an EUAC equation. Prepared by Dr.K.S.Badrinathan 39 Return On Investment (ROI) Method Total Investment = Rs.30 lacs Anticipated revenue = Rs.18 lacs/year Operating cost = Rs.6 lacs/year Service life of robot = 5 years MARR = 30% EUAC = 30lacs(A/P,i,5) + 18lacs 6lacs=0 (A/P,i,5) = 12lacs/30lacs = 0.4 For i=25% (A/P,25%,5)= For i=30% (A/P,30%,5)= Rate of return = 30% Prepared by Dr.K.S.Badrinathan 40 20

21 END OF UNIT V Prepared by Dr.K.S.Badrinathan 41 21