interaksi manusia – mesin · sistem' manusia'mesin'...
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Interaksi Manusia – Mesin !ANALISA DAN PENGUKURAN KERJA
Debrina Puspita Andriani e"Mail':'[email protected]'
Blog':'http://debrina.lecture.ub.ac.id/'
Jurusan'Teknik'Industri'Semester'Gasal'2014/2015'
3
OU
TL
IN
E(
Analisa(Kuantitatif(Sistem(Manusia(7(Mesin!
Sistem(Manusia(Mesin(
Model(Hubungan((Manusia(7(Mesin!
Analisa(Sistem(Manusia(7(Mesin!
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Manusia(vs(Mesin(Kecepatan(( Cepat(Lambat(
Kekuatan( Kecil,(terbatas,(berubah7ubah(Dapat(diatur(dengan(baik,(
bisa(diperbesar,(tetap(
Keseragaman( Tidak(dapat(diandalkan,(perlu(di7monitor(
Seragam(/(standar,(cocok(untuk(pekerjaan(massal(
Memory! Mengingat(segala(macam,(persepsi,(dasar(&(strategis(
Sesuai(perintah,(jangka(panjang(/(jangka(pendek(
Berpikir( Induktif(baik( Deduktif(baik(
Kalkulasi( Lambat,(mungkin(ada(error,(kemampuan(koreksi(
Cepat,(tepat,(tidak(ada(koreksi(
Overload! Degradasi,(kemampuan(turun(perlahan( Kerusakan(tiba7tiba(
Kepintaran( Kemampuan(adaptasi,(meramal,(menganalisa(
Keputusan(Ya/Tidak(sesuai(program(
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SISTEM'MANUSIA'MESIN'Kombinasi'1'atau'beberapa'manusia'dengan'1'atau'beberapa'mesin'yang'saling'berinteraksi'untuk'menghasilkan'output'berdasarkan'input'tertentu.'
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MESIN'semua'objek'fisik'termasuk'peralatan,'perlengkapan,'fasilitas'&'benda"benda'yang'digunakan'manusia'dalam'melakukan'pekerjaannya'
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Man(Machine(Interface((
MAN( MACHINE(
PERCEPTION(&(CONTROL(01/10/2014( www.debrina.lecture.ub.ac.id(6(
Simple(Ergo(System(
H
e( e(
e'='Environment'
='Human' ='Machine'
H M
H M
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Complex(Ergo(System(
H
e( e(
e'='Environment'
='Human' ='Machine'
H M
H M
MM M
M
HH
H
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PERFORMING(TASK(
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Firmware(Software"Loaded'Hardware'for'
Proper'Identification'Hardware(Display'Control,'
Machine,'Equipment','etc' Human(Operator(
Age,'Sex,'Education,'Experience,'etc'
Software(Man,'
Manuals,'Information
,'etc'(
Feedback(
INPUT(OUTPUT(
ENVIRONMENT(Heat/Cold,+Noise,+Lighting,+Vibration,+etc+
TASK(
Model(Hubungan((Manusia(7(Mesin'
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Manual((Man7Machine(System!
Semi&Automa,c!!Man&Machine!System!
Automa,c!Man7Machine(System!
MANUAL((MAN7MACHINE(SYSTEM(
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(Human)(
Information(Storage(
Sensing((
Processing(
Action(
Feedback(
INPUT( OUTPUT(
SEMI7AUTOMATIC((MAN7MACHINE(SYSTEM(
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(Human)(
Information(Storage(
Processing(
Sensing( Action(
Dis
play
Con
trol
M
echa
nism
Process(INPUT(
OUTPUT(
Feedback(
AUTOMATIC(MAN7MACHINE(SYSTEM(
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Information(Storage(
Processing(
Sensing( Action(INPUT( Process( OUTPUT(
Dis
play
Con
trol
m
echa
nism
(Machine)(
Human(((Monitor)(
Feed!back(
MECHANIS
MS( Recording!display!!:'memberi'informasi'tentang'progress'
dari'proses'kerja'yang'berlangsung'('kinerja'mesin')''Perception(:'operator'yang'menyerap'/'menangkap'informasi'dari'display'secara'visual''Interpretation!Decision!:'menginterpretasikan'dan'mengartikan'informasi'yang'masuk'dan'selanjutnya'membuat'keputusan''Handing!of!Controls!:'mengkomunikasikan'keputusan'yang'diambil'ke'sub"sistem'mesin'melalui'rancangan'mekanisme'kendali''Control!Display!:'memberikan'petunjuk'kepada'operator'hasil'dari'keputusan'dan'tindakannya.'Selanjutnya'mesin'akan'membawa'ke'dalam'bentuk'aktivitas'kerja'
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Analisa(Sistem((Manusia(7(Mesin(
KUALITATIF(:(
! Peta'Manusia'"'Mesin'('Man+8+Machine+Process+Chart+)'
! Menentukan(berapa(jumlah(mesin(/(fasilitas(kerja(yang(bisa(dioperasikan(oleh(seorang(operator.(
! Sederhana,'praktis'dan'cepat.'
! Kendala':'Ketelitian'dalam'menggambar'peta'manusia"mesin'
KUANTITATIF(:(! Pengembangan'model'
matematis.'
! Lebih'teliti,'akurat,''dan'memasukkan'variabel''''''''''''''''''''''''biaya'dalam'proses'analisanya.'
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Analisa(Kuantitatif(Sistem(Manusia(7(Mesin'
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Synchronous!Servicing!
Completely!Random!Servicing!
Combina,on!Servicing!
Synchronous!Servicing'
• Kondisi'kerja'ideal'
• Operator'dan'mesin'bekerja'secara'penuh'dalam'siklus'waktu'yang'tersedia.'
• Operator'lebih'sering'berada'dalam'kondisi'“idle”,'sehingga'untuk'itu'bisa'dibebani'kerja'dengan'melayani'operasi'mesin'yang'kedua,'ketiga,'dst"nya.'
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Synchronous!Servicing'
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! 1'operator'menangani'>'1'mesin'''DALAM(KONDISI(IDEAL'"'SINKRON.'
'! Formulasi(:''''
'''Dimana':''N''=' 'Σ'mesin'yang'harus'dilayani''' '(unit'mesin)''L'''=' 'total'operator+servicing+time''' '(loading+&+unloading)'(jam)''m''='total'machining+time'(jam)'
''
Lm##L
#time#operatortime#machine##N +
==
Synchronous!Servicing+
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St' St'
St' St'
St' St'
St'
St'
St'
St'
Cycle'time'"'Ct'
Ct'
Ct'
Ct'
Ct'
m/c(#(1(
m/c(#(2(
m/c(#(3(
m/c(#(4(
m/c(#(5(
St'='L'='service+time+(loading+&+unloading);''Ct'='m'='cycle+time'atau'machining+time+
Synchronous!Servicing(
! Kondisi'ideal'sulit'untuk'bisa'dicapai;'bilamana'N'>'5'atau'N'<'5'(dari'contoh)'maka' akan' dijumpai' situasi' adanya' idle' atau' delay+ yang+ bisa' terjadi' pada'mesin'atau'operator.+
! Kondisi' idle' atau'delay'bisa' terjadi'manakala'nilai'N'dari' perhitungan'akan'menghasilkan' bilangan' pecahan;' sedangkan' banyaknya' mesin' yang' harus'dioperasikan'merupakan'bilangan'bulat.'
! Pertimbangan' manakah' yang' sebaiknya' “idle”?' (Idle( machine( or( idle(operator?)'
! Formulasi' perhitungan' jumlah' mesin' yang' dioperasikan' oleh' seorang'operator' perlu' modifikasi' dengan' memperhitungkan' waktu( (w)( yang(diperlukan(oleh(operator(untuk(bergerak7pindah(dari(satu(mesin(menuju(ke(mesin(berikutnya.' ' Pada' formulasi' terdahulu,'dalam'kondisi' yang' ideal'waktu'(w)'dianggap'='NOL'(?)+
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! Dengan' memperhitungkan' waktu( bergerak7pindahnya( operator( (w);'maka' jumlah'mesin' yang' harus' dilayani' bisa' dihitung' dengan' formulasi'baru'sbb':'
'
''
# Nilai'N'merupakan'bilangan'bulat.' 'Bilamana'dijumpai'nilai'N'merupakan'bilangan'pecah'misalkan'N'='4.57);'maka'perlu'untuk'dibulatkan'kebawah'(N1'='4)'atau'dibulatkan'keatas'(N2'='N1'+'1'='5). ' ''
# Untuk'menetapkan' berapa' jumlah'mesin' yang' seharusnya' dioperasikan'oleh' seorang' operator' dapat' ditetapkan' berdasarkan' pertimbangan'(analisa' biaya)' yang' didasarkan' pada' The( Expected( Cost( (TEC)' yang'paling' ekonomis' dilihat' dari' aspek' idle/delay' costs' yang' terjadi' pada'mesin'atau'operator.'
'''''''''
w""Lm""L""N
+
+=
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Synchronous!Servicing(
The!Expected!Cost!
! The(Expected(Cost(:(! CM'='machining'cost'(Rp/jam/mesin)'! CO'='operator'cost'(Rp/jam/operator)''
! N1(=(idle(mesin((($(),(waktu'siklus'"'waktu'siklus'mesin'! N2(=(idle(operator(((%(),(waktu'siklus'"'waktu'siklus'operator'
'
! Keputusan':'Pilih'jumlah'mesin'yang'memberikan'nilai'TEC(terkecil(( ( (TECN1(<(TECN2("(Pilih(N1((( (TECN1>TECN2("(Pilih(N2(
1
M1oN1 N
).CNm)(C(LTEC ++= ).CNw)(C(LTEC M2ON2 ++=
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Berapakah'jumlah'mesin'yang'seharusnya'bisa'dilayani'oleh'seorang'operator,'bilamana'diketahui':'''
" Waktu'yang'dibutuhkan'untuk'kegiatan'loading'&'unloading''adalah'1,41'menit.'
" Waktu'yang'dibutuhkan'untuk'operator'bergerak'berpindah'dari'satu'mesin'ke'mesin'lainnya'0,08'menit.'
" Waktu'permesinan'4,34'menit.'" Biaya'operator'Rp.'8500'/'jam/operator.'" Biaya'operasi'mesin''Rp.'15000'/'jam/mesin.'
LATIH
AN(SOAL(01/10/2014( www.debrina.lecture.ub.ac.id(23(
PENYELESAIA
N(
3,860,08&&1,414,34&&1,41
w&&Lm&&L&&N =
+
+=
+
+=
N1'='3';'N2'='4'
Rp.1.7093
3x15000)(8500(5,75/60)N
).CNm)(C(LTEC1
M1ON1
=
+=
++=
Rp.1.701'4x15000)8500(1,49/60)().CNw)(C(LTEC M2ON2
=
+=
++=
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Completely!Random!Servicing!
# Diaplikasikan'untuk'menghadapi'kondisi':'& Kapan' suatu' fasilitas' kerja' memerlukan' pelayanan'operator'TIDAK(DIKETAHUI;'
& Berapa' lama' pelayanan' terhadap' fasilitas' kerja' tersebut'harus'berlangsung'juga'TIDAK(DIKETAHUI.(
# Mesin'dapat'berhenti'(down)'karena:'
' Siklus'kerja'selesai'(dan'ada'proses'loading'atau'unloading+yang'dilakukan'oleh'operator).'
' Mesin'rusak'sehingga'operator'harus'melakukan'perbaikan'(maintenance+services)'
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Completely!Random!Servicing!
# Probabilitas'mesin'down'(memerlukan'pelayanan'operator)':'0,'1,'2,'3'…'n'(n'relatif'kecil).''
# Kapan' pelayanan' dikehendaki' dan' berapa' lama' waktu' pelayanan'(service)'bersifat'acak'(random).'
# Pendekatan'Distribusi!Binomial'digunakan'untuk'penyelesaiannya.'
# Di"ASUMSI"kan'bahwa'mesin'akan'down'/'idle'secara''random''selama'siklus'kerja'berlangsung''
# p(=(probability(of(running(time(
# q(=(probability(of(down/idle(time(
# p(+(q(=(1(
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Teorema(Ekspansi(Binomial'
( ) ( ) ( ) nxnxnx
2n2n2
1nn1
nn q....pq....pqqppq)(p ++++++=+ −−−
Binomial(Distribution(
'Proporsi(waktu(mesin(yang(hilang((d):(''''Jika' prosentase' jam' yang' hilang' ±( 10%( maka' dapat' dikatakan'bahwa'penugasan'sudah'baik.''Sedangkan' bila' prosentase' jam' mesin' yang' hilang' terlalu' besar,'maka'dapat'ditambah'operator'yang'menangani'mesin'down.'
100%mesin)kerja)jam)Total
hilang)yang)mesin)kerja)jam)Total×
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C((O((N((T((O((H'
Tentukan'porsi'minimal'dari'waktu'permesinan'yang'akan'hilang'untuk'pengoperasian'3((tiga)(mesin'yang'harus'dilayani'oleh'seorang'operator'bila'diketahui':'• Rata"rata'running+time+='60%'
• Rata"rata'operator+attention+time'='40%'(irregular+intervals).''
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! Kemungkinan'(probabilitas)'adanya'mesin'running'(p)'dan'down/idle' (q)'untuk'3(mesin(yang'harus'dilayani'oleh' seorang' operator' dapat' ditunjukkan' sebagai'berikut':'
'(p'+'q)n' '='(p'+'q)3''
' '='p3'+'3p2q'+'3pq2'+'q3'
''''''''''''' '='(0.60)3'+'3(0.60)2(0.40)'+'3(0.60)(0.40)2'+'(0.40)3'
'''''' ' '='(0.216)'+'(0.432)'+'(0.288)'+'(0.064)'''''''''''''''''''''''''''''''''''''''''
Perhitungan(Distribusi(Binomial(
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Mesin(1''''''Mesin(2''''''''Mesin(3''''''''''''''Probabilitas(
R'='0.60'R'='0.60'''''''''''(0.60)(0.60)(0.60)'='0.216''''''''''''''''''''D'='0.40'''''''''''(0.60)(0.60)(0.40)'='0.144'
D'='0.40' R'='0.60'''''''''''(0.60)(0.40)(0.60)'='0.144'D'='0.40'''''''''''(0.60)(0.40)(0.40)'='0.096'
R'='0.60'
R'='0.60'R'='0.60'''''''''''(0.40)(0.60)(0.60)'='0.144'D'='0.40'''''''''''(0.40)(0.60)(0.40)'='0.096'
D'='0.40'R'='0.60'''''''''''(0.40)(0.40)(0.60)'='0.096'D'='0.40'''''''''''(0.40)(0.40)(0.40)'='0.064'
D'='0.40'
1.000'
Tree!Diagram!
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! Dari'perhitungan'tersebut'diatas,'maka'proporsi'waktu'mesin'down/idle'bisa' ditentukan.' ' Waktu' yang' hilang' untuk' melayani' 3' mesin' dapat'dihitung'sebagai'berikut:'
#'mesin'down/idle'
Probability( Jam'mesin'yang'hilang''karena'1'operator'
Jam'mesin'yang'hilang'karena'2'operator'
0' 0.216' 0' 0'
1' 0.432' ''0*)' 0'
2' 0.288'' (1)(0.288)(8)'='2.304' 0'
3' 0.064' (2)(0.064)(8)'='1.024' (1)(0.064)(8)'='0.512'*)+Karena+hanya+1+(satu)+mesin+yang+down+maka+operator+dapat+melayani+mesin+tersebut,+sehingga+secara+
keseluruhan+tidak+ada+mesin+yang+“down/+idle”.++
• 'Proporsi'waktu'permesinan'yang'hilang'karena'hanya'1'(orang)'operator'saja'yang'ditugaskan'melayani'3'(tiga)'mesin'=''(2.304'+'1.024)'
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''3'x'8'x'100%'='13.9%'
Proporsi(Waktu(Hilang(
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The!Expected!Cost!
Asumsi':'• Biaya'operator'='Rp'10.000/jam'• Biaya'permesinan'='Rp'80.000/jam'• Output'produksi'='250'unit/jam''''''''''''''''''''''''Untuk(1(operator(:(Produksi'selama'8'jam'='(24'–'3,328)'x'250'='5168'unit'Biaya'selama'8'jam'='(10000'x'8)'+'(80000'x'3'x'8)'='Rp'2.000.000'Biaya'per'unit'='2000000'/'5168'='Rp'386,9'
Untuk(2(operator(:(Produksi'selama'8'jam'='(24'–'0,512)'x'250'='5872'unit'Biaya'selama'8'jam'='(10000'x'8'x'2)'+'(80000'x'3'x'8)'='Rp'2.080.000'Biaya'per'unit'='2080000'/'5872'='Rp'354,2'
Untuk(3(operator(:(Produksi'selama'8'jam'='(24'–'0)'x'250'='6000'unit'Biaya'selama'8'jam'='(10000'x'8'x'3)'+'(80000'x'3'x'8)'='Rp'2.160.000'Biaya'per'unit'='2160000'/'6000'='Rp'360'01/10/2014( www.debrina.lecture.ub.ac.id(32(
Tentukan' minimum' prosentase' dari' waktu' permesinan' yang'akan' hilang' dan' jumlah' operator' optimum'untuk'menangani' 4'(empat)' mesin,' bila' rata"rata' running+ time+ 70%' dan' rata"rata'operator+attention+time'sebesar'30%.'
Asumsi':'Biaya'tenaga'kerja'langsung':'Rp'12.500/jam'Biaya'permesinan':'Rp'85.000/jam'Output'produksi':'300'unit/jam'
LATIH
AN(SOAL(
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Combination!Servicing!+
• Servicing'Time'"'Constant(• Machine'Down'Time'"'
Random(• Sebuah'tipikal'umum'dari'
sistem'manusia'mesin.'• Problem'teori'antrian'
(Queuing+Theory)'yang'bisa'dijumpai'cara'penyelesaiannya'dalam'riset'operasi'(Operation+Research)'
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“The best way to predict the future is to invent it” - Alan Kay -
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