cs.ROMar 19, 2026

TiBCLaG: Hybrid design approach for a trigger-induced bistable compliant laparoscopic grasper

Authors: Joel J Nellikkunnel, Prabhat Kumar

Organizations: Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Telangana 502285, India

Read PDF
Ask AI
Cite

Copy citation

DOINot available for this paper

Abstract

Industrial laparoscopic graspers rely on multi-link rigid mechanisms manufactured to tight tolerances, resulting in high manufacturing and assembly costs. This work presents the design and proof-of-concept validation of a monolithic, fully compliant, bistable, laparoscopic grasper that eliminates the need for multiple rigid links, thereby reducing part count. The device integrates a compliant trigger and a compliant gripper end-effector, coupled via a control push-rod, to achieve stable grasping without continuous user input. A hybrid approach combining an analytical model, iterative prototyping, and finite element analyses is employed to design the laparoscopic grasper. The trigger mechanism is synthesized using a Two-Element Beam Constraint Model as a design framework to control the deformation and stiffness of I-beam-like elements. This technique enables elastic energy storage while preventing snap-through instability. The end-effector is designed as a compliant gripper to achieve adaptive grasping through elastic deformation. The laparoscopic design presented here is fabricated using fused deposition 3D printing. A comparative study of the jaws' opening and closing performance is presented using nonlinear finite element analysis and experimentation. The fabricated prototype demonstrates reliable bistable actuation, confirming the feasibility of such compliant laparoscopic grasper architectures.

Figures & tables

Figure 1
Figure 1: Plan view of the 3D CAD model of the proposed device.
Figure 2: The fabricated prototypes in their unstressed states: 2(a) Prototype 1, 2(b) Prototype 2 and 2(c) Prototype 3, and the fabricated prototypes in their stressed states: 2(d) Prototype 1, 2(e) Prototype 2 and 2(f) Prototype 3. The out-of-plane hooks (in Prototype 2 and Prototype 3) permit the trigger to operate satisfactorily.
Figure 3: The displacement profiles of Prototype 2 (Fig. 3(a) ) and Prototype 3 (Fig. 3(b) ) along the xx direction (the control push-rod direction) in its stressed state. The displacement of the shuttle in this direction is indicated as the second value in the annotation in the plots. The shuttle displacement is higher for Prototype 3 (Fig. 3(b) ) compared to Prototype 2 (Fig. 3(a) ).
Figure 4: Plan view of the 3D CAD model of the Gripper.
Figure 5: The FEM analysis results of the five-beam and the final six-beam configuration. The stresses induced in the five-beam configuration (Fig. 5(a) ) are much higher than in the six-beam configuration (Fig. 5(b) ). The six-beam configuration (Fig. 5(b) ) presents a suitable compromise between the displacement of the gripper jaws and the stresses induced.
Figure 6: Snapshots of the FEM analysis of the final laparoscopic grasper prototype at the end of 6(a) Step 1 (3.2mm displacement) and 6(b) Step 2 (6.4mm displacement).
Trigger Displacement [mm]Maximum Stress [MPa]Jaw Displacement [mm]
3.236.357.13
6.474.7915.99
891.6120.52
Table 1: Stresses and Displacements during Retraction of Trigger
Figure 7: Results obtained from the final printed prototype. The final prototype of the laparoscopic grasper is presented in its two states, 7(a) closed and 7(b) open. Comparison of the gripper jaw displacement with the circular pull-back ring displacement obtained from finite element analysis and experiments is presented in Fig. 7(c) .
Table 2: Pictorial Comparison between the FEM and experimental deformed profiles of the laparoscopic grasper. The comparison between the displacements of the jaw and the ring are illustrated in Fig. 7(c)
Figure 8: The experimental setup used to measure the variation of jaw displacement versus force applied on the circular pull-back ring. The force is applied using masses of known weight, and the displacement is measured manually using an electronic vernier caliper. The marker in Fig. 8(e) indicates the location of points where the vernier caliper measurements are taken to ensure correlation with the maximum displacement results obtained using FEM analysis.
Figure 9: The laparoscopic grasper in use, gripping a piece of packing foam.
Figure 10: Variation of the gripper jaw displacement with the force applied to the circular pull-back ring of the laparoscopic grasper.
More in this topic

Mechanism Design

Mechanism design studies rules for allocating resources and shaping incentives when participants hold private information or act strategically.

See all 142 papers

Explore similar work

CardsList

  1. A passive universal grasping mechanism based on an everting shell

    May 30, 2026Mythra V. S. Balakuntala, Safvan Palathingal, G. K. AnanthasureshRobotic GraspingSoft Robotics

    Indian Institute of Science, Bengaluru, India

  2. Robot Aware Computational Design of Object Specific Passive Grippers for Additive Manufacturing

    Sep 3, 2026Abdullah Yahya Abdullah Omaisan, Ibrahim Sheikh MohamedRobotic GraspingRobotic Gripper Design

    1Independent Researchers, Riyadh, Saudi Arabia. · 2QSS AI and Robotics Lab, Riyadh, Saudi Arabia.

  3. Control Architecture for Safe Grasping of Fragile Objects Using a Coarse Position-Controlled Gripper

    Sep 11, 2026Marko Pavlic, Moritz Geier, Timo Markert +1Robotic GraspingContact-Rich Robotic Manipulation

    Machine Vision and Perception Group, Chair of Robotics, Artificial Intelligence and Real-time Systems, Technical University of Munich, Munich, Germany · Resense GmbH, Klingenberg, Germany · Semantic Information Systems Group, Osnabrück University, Osnabrück, Germany