“…Park, Park, and Foley 2003) Costs Picking cost (Lee and Kuo 2008) Robotic parts-to-picker OPSs Throughput Throughput (Bauters et al 2016; Lamballais, Roy, and De Koster 2017; Lamballais Tessensohn, Roy, and De Koster 2020; Roy et al 2019) Lead time Average order cycle time (Ekren and Heragu 2010; Lamballais, Roy, and De Koster 2017), throughput time (Yuan and Gong 2017; Roy et al 2019), picking time (Xue, Dong, and Qi 2018; Zou, Xu, and De Koster 2018) Human factors Ergonomics (Lee, Chang, and Choe 2017; Hanson, Medbo, and Johansson 2018), operator training (Hanson, Medbo, and Johansson 2018) Quality Picking accuracy (Hanson, Medbo, and Johansson 2018) Flexibility Flexibility (Hanson, Medbo, and Johansson 2018) Operational efficiency Robot utilisation (Lamballais, Roy, and De Koster 2017), uptime (Hanson, Medbo, and Johansson 2018), collision-free paths (Kumar and Kumar 2018), waiting times for vehicles (Ekren and Heragu 2010), average utilisation of vehicles and lifts (Ekren and Heragu 2010), effeciency (Zhao et al 2019), picker and robot utilisation (Wang, Chen, and Wang 2019), robot travel time (Wang, Yang, and Li 2019). Costs Costs (Boysen, Briskorn, and Emde 2017), costs (Li et al 2017) Robot-to-parts OPSs Lead time Picking time (Zhu et al 2016), picking cycle time (Boudella, Sahin, and Dallery 2018) Flexibility Easily adjusted to changes in product quantity (Kimura et al 2015) Costs Investment costs and payback period (Bonini, Urru, and Echelmeyer 2016) Parts-to-robot OPSs Throughput Throughput (Derby 2008) Lead time Cycle time (Kim et al 2003a), picking time (Khachatryan and McGinnis 2005) Flexibility Adapt robot to pick new items (Dieter Schraft and Ledermann 2003) Operational efficiency Robot travel time (Kim et al 2003b), robot utilisation (Li and Bozer 2010) Picker-less OPSs with dispensers Throughput Throughput (Liu et al 2011) Lead time Picking time (Yigong 2008) Human factorsSafety(Franklin et al 2008)Staff satisfaction(Franklin et al 2008) Quality Picking error(Franklin et al 2008) Operational efficiencyEfficiency(Franklin et al 2008) CostsOperational costs(Caputo and Pelagagge 2006;Liu et al 2011) Picker-less OPSs with A-frames Throughput Throughput (Pazour and Meller 2011) Lead time Picking time (Jin, Yun, and Gao 2015) Operational efficiency Dispensing efficiency(Jin, Yun, and Gao 2015)Picker utilisation(Boywitz, Schwerdfeger, and Boysen 2019) Costs Total restock cost(Liu et al 2008)Replenishment and picking costs(Meller and Pazour 2008)Infrastructure investment(Meller and Pazour 2008)…”