Model Calibration for a Rigid Hexapod-Based End-Effector with Integrated Force Sensors

Area of Science:

• Robotics and Mechatronics
• Sensor Technology
• Control Systems Engineering

Background:

• Hexapod robots require precise force measurement for advanced applications.
• Integrated single-axis force sensors offer cost-effective 6-degree-of-freedom (6-DOF) force sensing.
• Internal forces necessitate compensation via measurement models, whose parameters can drift over time.

Purpose of the Study:

• To develop and evaluate fast and efficient parameter identification procedures for force measurement models in hexapod end-effectors.
• To compare the effectiveness of quasi-static versus dynamic excitation strategies for model calibration.
• To ensure accurate force measurement despite changing model parameters during machine usage.

Main Methods:

• Development of measurement and parameter identification models for a rigid hexapod end-effector.
• Analysis of parameter sensitivities within the force measurement model.
• Optimization and comparison of two excitation strategies: quasi-static poses and accelerated continuous trajectories.
• Experimental validation using reference payloads.

Main Results:

• Both quasi-static and accelerated trajectory-based excitation strategies enable accurate parameter identification.
• Optimized excitation strategies significantly improve the efficiency and accuracy of the calibration procedure.
• The proposed methods allow for rapid calibration, suitable for operational machine states.

Conclusions:

• Fast and accurate parameter identification for 6-DOF force measurement models in hexapod systems is achievable.
• The choice between quasi-static and dynamic excitation can be optimized based on specific application requirements.
• The developed calibration procedures are practical for real-world robotic applications, ensuring sustained measurement accuracy.