In this talk we will review a series of collaborative studies on the development and testing of robot companion applications for older people. One project is based on the interaction of three robot companions (for indoor and outdoor services) with older people users. Another project looks at the integration of robotic agents within a wider ambient intelligence setup, combining social robots with IoT sensors. These systems combine social robotics and human-interaction principles with AI and machine learning methods. We will also discuss aspects of trust in human-robot interaction, the strategies for verbal and non-verbal communication and ethics principles for transparent robots.