Development of a Low-Cost Force Sensory System for Force Control via Small Grippers of Cooperative Mobile Robots Used for Fabric Manipulation

The development and installation of a low-cost force sensory system (FSS) on a relatively small mobile robot, as well as the design of a proper force controller for fabric manipulation by two cooperative mobile robots, is presented. The FSS consists of two half bridge strain gauge setups which are integrated into a special fabric gripper of a differential-drive wheeled mobile robot (WMR). The FSS is calibrated and experimentally tested through measurements of varying horizontal 2D forces applied on a fabric during its simultaneous manipulation by the FSS-WMR and another robot. The FSS-WMR is used as a follower in a leader-follower formation for the control of the applied forces on the fabric via two independent PID controllers with force feedback. The performance assessment of the FSS-WMR is achieved via experiments with two cooperative WMRs for the transfer of a fabric in straight and curvilinear trajectories. The results indicate that the FSS-WMR may lead to the effective manipulation of fabrics in planar surfaces using two mobile robots, retaining tensional forces within fabric limits, thus rendering the new low-cost FSS a promising option for such types of fabric manipulation.