Recent progress in pressure and temperature tactile sensors: principle, classification, integration and outlook

Tactile sensors have received increasing research interest owing to the broad applications in areas of health monitoring, artificial intelligence, robotics, and prosthetics. The ability to understand and perceive touch and heat is of importance because it helps people to recognize objects, prevent injury, and provide heat information from grasped objects. However, bimodal tactile sensors often suffer from signal interference and complicated fabrication process. Numerous efforts have been undertaken to develop highly independent sensors based on different transduction principles as well as the device integration techniques. Here, strategies for improvement of main performance parameters such as sensitivity, sensing range, hysteresis, response/recovery time, and stability are discussed. A comprehensive overview of important progress in pressure and temperature tactile sensors in recent years is summarized. According to sensor units and transduction principles, temperature and pressure tactile sensors are categorized into two types: dual-parameter sensors and integrated bimodal sensors. Integration of tactile sensors from the viewpoint of power supply, wireless communication, and signal process circuit is given. Finally, challenges and outlook are provided and presented for pressure and temperature tactile sensors.