Automated Safety Testing System for Cranial Trepanation Drills
Challenge
Medical device manufacturers require extensive validation of surgical tools before they can be approved for clinical use. One such challenge involved testing the safety and performance of cranial trepanation drills used during neurosurgical procedures.
The objective was to develop an automated testing platform capable of realistically simulating the drilling process while measuring force and torque characteristics with high precision. The system needed to reproduce changing drilling conditions, acquire high-frequency measurement data, automatically evaluate test results, and provide full traceability through electronic reports.
In addition, the solution had to support operation within a regulated environment following principles aligned with CFR 21 Part 11 and GAMP 5 requirements.
Solution
The testing platform was built around a Beckhoff C6930 Industrial PC running TwinCAT 3.
A surgical drill drive identical to the equipment used in operating rooms was mounted within the machine to replicate real-world operating conditions. During testing, the drill was coupled to a measurement shaft connected to a dynamometer capable of accurately measuring torque generated throughout the drilling process.
The drilling force applied during testing was controlled using pneumatic actuators equipped with Festo proportional pressure regulators. Closed-loop force control was implemented using load cell feedback, allowing the system to precisely regulate applied force throughout the test cycle.
A second force-controlled actuator was used to simulate changing material resistance encountered during skull penetration. By applying a decreasing force profile, the machine could reproduce realistic drilling conditions and generate repeatable test scenarios.
High-speed force and torque measurements were acquired using National Instruments EtherCAT oversampling I/O modules integrated directly into the Beckhoff control architecture. This allowed data to be captured at significantly higher rates than the standard PLC cycle time, providing detailed measurement waveforms for analysis.
The entire testing process was automated through TwinCAT software, including force control, data acquisition, result evaluation, report generation, and traceability management.
A TwinCAT HMI application provided operators with recipe management, user management, alarm handling, diagnostics, and access to generated reports.
Machine safety functions were implemented using TwinSAFE technology.
System Architecture
settings_applications
Test Drive Integration
Surgical drill drive identical to clinical equipment
Mechanical coupling system
Automated test execution
sensors
Force Control System
Pneumatic actuators
Festo proportional pressure regulators
Closed-loop force control
Load cell feedback
query_stats
Measurement System
Dynamometer integration
Force measurement
Torque measurement
Waveform acquisition
bolt
High-Speed Data Acquisition
National Instruments EtherCAT Oversampling I/O
High-frequency signal capture
Detailed force and torque analysis
web
HMI and Reporting
TwinCAT HMI
Recipe management
User management
Alarm management
Automated report generation
lock
Safety
TwinSAFE implementation
Safe machine operation
Safety monitoring
Key Responsibilities
TwinCAT 3 PLC software development
Closed-loop force control implementation
Integration of proportional pressure regulators
Load cell integration
Dynamometer integration
High-speed measurement acquisition
TwinCAT HMI development
TwinSAFE implementation
Automated report generation
Commissioning and validation support
Results
The completed system provided a realistic and repeatable simulation of the cranial drilling process while delivering highly accurate force and torque measurements.
Key achievements included:
Automated validation of surgical drilling devices
Realistic simulation of changing drilling conditions
Precise closed-loop force control
High-speed acquisition of force and torque waveforms
Automated pass/fail evaluation based on measurement characteristics
Electronic report generation and result traceability
Support for regulated medical device development environments
The platform enabled engineers to evaluate product performance, compare design iterations, and generate repeatable validation data without relying on manual testing procedures.
Technologies
Beckhoff C6930
TwinCAT 3
EtherCAT
National Instruments EtherCAT Oversampling I/O
TwinSAFE
TwinCAT HMI
Festo Proportional Pressure Control
Load Cells
Dynamometer Integration
Closed-Loop Force Control
Force & Torque Measurement
Automated Reporting
CFR 21 Part 11 Environment
GAMP 5 Environment
Looking for TwinCAT expertise in testing and validation systems?
Whether you’re developing automated test equipment, force-control applications, data acquisition systems, or regulated manufacturing solutions, I can help design and implement robust Beckhoff TwinCAT-based platforms.