Exploring the Effect of Base Compliance on Physical Human-Robot Collaboration

Mobile physical human-robot collaboration (pHRC) using collaborative robots (cobots) and mobile robots has attracted much research attention. Many researchers have focused on improving the control performance to comply with human intentions. However, a problem that generally exists with mobile pHRC but often gets neglected is the impact of non-rigid components e.g. deformable tyres, suspension systems and uneven terrain on human interaction experience and task performance. To fullfil this current research gap, we carried out an investigation on the above-mentioned problem by altering a cobot’s base rigidity level (also referred to as base compliance level or BCL) during pHRC experiments. We explored how the task performance is affected by base compliance as well as human operator’s experience and cobot control parameters. Measurements include the human operator’s physical effort, task velocity, and task error. From the experimental results, it is discovered that base compliance has a significant impact on task accuracy as it can easily excite the system if an inadequate control strategy is deployed. Furthermore, through ANOVA, it is discovered that the influence of base compliance can be minimized and system excitation can be avoided by sufficient human operator training and the appropriate selection of cobot’s control parameters.