Effective system integration requires strict adherence to strong software engineering standards, a practice not much favoured in many collaborative research projects. We argue that component-based software engineering (CBSE) provides a way to overcome this problem because it provides flexibility for developers while requiring the adoption of only a modest number of software engineering practices. This focus on integration complements software re-use, the more usual motivation for adopting CBSE. We illustrate our argument by showing how a large-scale system architecture for an application in the domain of robot-enhanced therapy for children with autism spectrum disorder (ASD) has been implemented. We highlight the manner in which the integration process is facilitated by the architecture implementation of a set of placeholder components that comprise stubs for all functional primitives, as well as the complete implementation of all inter-component communications. We focus on the component-port-connector meta-model and show that the YARP robot platform is a well-matched middleware framework for the implementation of this model. To facilitate the validation of port-connector communication, we configure the initial placeholder implementation of the system architecture as a discrete event simulation and control the invocation of each component’s stub primitives probabilistically. This allows the system integrator to adjust the rate of inter-component communication while respecting its asynchronous and concurrent character. Also, individual ports and connectors can be periodically selected as the simulator cycles through each primitive in each sub-system component. This ability to control the rate of connector communication considerably eases the task of validating component-port-connector behaviour in a large system. Ultimately, over and above its well-accepted benefits for software re-use in robotics, CBSE strikes a good balance between software engineering best practice and the socio-technical problem of managing effective integration in collaborative robotics research projects.