Static workspace validation incorporating friction on a suspended reconfigurable cable-driven robot

Overview & Synopsis

Underactuated suspended four-cable parallel robots tend to tilt under load, limiting the region in which the platform can remain horizontal. Pose accuracy is further affected by small variations in cable tension and actuator friction. A reconfigurable architecture with mobile attachment points driven by platform-mounted sliders is introduced to mitigate these limitations, enabling improved orientation control, workspace enlargement, and collision avoidance. A method is developed to compute the Static Equilibrium Workspace (SEW) of a suspended reconfigurable prototype, incorporating actuator friction into the static model under tension, orientation, and slider constraints. Experimental validation using an OptiTrack system and strain-gauge measurements confirms the accuracy of the model. The results indicate that platform reconfigurability increases the SEW from 25.2 % to 84.8 %, friction modeling reduces positioning errors by 49.7 %, and measured cable tensions match theoretical predictions with an average deviation of 1.3 N.