Typical robot development requires that hardware be mostly functional before significant software development begins. Utilizing virtual prototype of hardware and its environment can reduce development time and manufacturing cost. Virtual prototyping is, however, a highly challenging task requiring in-depth knowledge in many disciplines. Few of simulation tools developed to alleviate this difficulty fully manage the complexity caused by the fact that developer must design and manage form (physical shape), function, and behavior altogether incrementally. Also, such simulation tools often do not support co-development of the target software and its test environment from requirements analysis to implementation. In this paper, we present our experience of developing a virtual prototype of Samsung Home Robot (SHR) with Samsung Advanced Institute of Technology (SAIT) using ASADAL/OBJ. Virtual prototyping in ASADAL/OBJ enables incremental co-development of both target system and its test environment in an object-oriented way. Furthermore ASADAL/OBJ facilitates concurrent development of form, behavior, and function. These features increase productivity as well as confidence through incremental refinement and validation. We give a brief background on the ASADAL/OBJ framework, then illuminate our experience of developing a virtual prototype of SHR.