The safe and reliable manipulation of fragile objects remains a central challenge in soft robotics, particularly for cable-driven grippers in which actuation forces are indirectly transmitted through highly compliant structures. For automation and control purposes, establishing a link between the actuation variable—cable tension—and a physically meaningful grasp metric, such as contact pressure, is essential for defining operational safety limits. This work investigates the mechanical behaviour of a SpiRob-type soft gripper, with a specific focus on the characterization of contact pressure distribution under actuation.
Rather than relying exclusively on detailed material calibration, this study explores modelling frameworks aimed at estimating the pressure generated at the gripper–object interface. The proposed approach analyses the structural response of the soft actuator to relate applied cable tension to the resulting contact pressure for objects with different geometries. Both theoretical and computational perspectives are employed to establish a robust mapping between actuation input and grasping performance. The resulting characterization enables the definition of pressure-based safety regions that are directly relevant to gripper design and low-level control strategies. By providing a practical method for estimating contact stress without the need for extensive experimental calibration, this work contributes to the development of safer, more predictable, and more controllable cable-driven soft robotic manipulation systems.