For effective and advanced shoulder rehabilitation of stroke survivors by using robotic devices, rehabilitation robots are required to conduct variety of rehabilitation tasks such as passive stretching and voluntary movement exercise in a same device. Those tasks require different control strategies and this paper presents how different control modes are implemented to conduct effective rehabilitation exercises. First, for the passive stretching, we present an effective stretching method using stiffness controlled velocity control. Second, for the voluntary movement exercise, zero force regulating control for free movement with adjustable resistance is developed. Those controllers provide control of physical interactive force while joint movements are measured. The two control modes can achieve the aimed rehabilitation tasks and are expected to achieve more effective rehabilitation.