Towards simulation-based optimization of compliant fingers for high-speed connector assembly

2025-09-12

AI Summary

To address assembly failures in high-precision connector mating caused by geometric deviations of workpieces, this paper proposes a simulation-driven design methodology for underactuated robotic fingers. Departing from conventional paradigms reliant on time-consuming hardware iterations or oversimplified planar contact models, our approach employs high-fidelity multibody dynamics simulation to jointly model nonlinear contact mechanics and frictional behavior. We formulate task success rate as the objective function and systematically optimize both the geometric configuration and spatial stiffness distribution of the finger. Experimental validation on the NIST Standard Task Board demonstrates that the designed finger tolerates misalignment up to 8.6 mm—improving error tolerance by 2.29×—and significantly enhances insertion success rate and operational robustness under dynamic contact conditions on a real robotic platform. The core contribution is a task-performance-oriented optimization framework for compliant mechanisms, overcoming the empirical dependency bottleneck in adaptability design for complex, multi-point contact scenarios.

Technology Category

• Intelligent Robots: Manipulation
• Search and Optimization: Sampling/Simulation-based Search
• Constraint Satisfaction and Optimization: Mixed Discrete/Continuous Optimization

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Mechanical compliance is a key design parameter for dynamic contact-rich manipulation, affecting task success and safety robustness over contact geometry variation. Design of soft robotic structures, such as compliant fingers, requires choosing design parameters which affect geometry and stiffness, and therefore manipulation performance and robustness. Today, these parameters are chosen through either hardware iteration, which takes significant development time, or simplified models (e.g. planar), which can't address complex manipulation task objectives. Improvements in dynamic simulation, especially with contact and friction modeling, present a potential design tool for mechanical compliance. We propose a simulation-based design tool for compliant mechanisms which allows design with respect to task-level objectives, such as success rate. This is applied to optimize design parameters of a structured compliant finger to reduce failure cases inside a tolerance window in insertion tasks. The improvement in robustness is then validated on a real robot using tasks from the benchmark NIST task board. The finger stiffness affects the tolerance window: optimized parameters can increase tolerable ranges by a factor of 2.29, with workpiece variation up to 8.6 mm being compensated. However, the trends remain task-specific. In some tasks, the highest stiffness yields the widest tolerable range, whereas in others the opposite is observed, motivating need for design tools which can consider application-specific geometry and dynamics.

Problem

• Optimizing compliant finger design parameters for connector assembly
• Addressing task-specific robustness challenges in dynamic manipulation
• Developing simulation-based tools to replace hardware iteration methods

Innovation

• Simulation-based optimization for compliant finger design
• Dynamic simulation with contact and friction modeling
• Task-specific parameter optimization for robustness improvement