Proximity and Contact Sensor Combining Multi-Zone ToF Sensors and a Self-Capacitance Sensor

In recent years, collaborative robots (cobots) that can operate safely with humans have gained popularity. Proximity and tactile sensors contribute to the safe operation of cobots in shared workspaces. This study proposes a time-of-flight (ToF) sensor and self-capacitance proximity and contact sensor that combines five wide field-of-view multi-zone ToF sensors with a self-capacitance electrode, allowing for installation on curved surfaces such as non-driven regions near joints and achieving wide-range measurements from proximity to contact. The combination of ToF and self-capacitance sensing allows seamless detection from non-contact to contact with fewer blind spots. Furthermore, real-time control based on the acquired data was implemented, demonstrating improved safety and operational efficiency during collaborative tasks by reducing robot speed and stopping its motion when proximity is detected. The proposed method allows for both curved-surface installation, including non-driven regions near joints, and continuous detection of proximity to contact in cobot safety systems.