During the process of the end effector of an industrial robot arm accurately tracking the welding path, there exist joint friction (disturbance) and communication time delay. To address such issues, this study investigates the performance output tracking problem of a one-dimensional unstable heat equation, where the model involves unknown external disturbances and the input end exhibits time delay.Based on the properties of the first-order transport equation, the control system can be modeled as a cascaded system consisting of a heat equation and a transport equation, with the transport equation serving as the actuator dynamic of the heat equation system. The system features a non-collocated structure; the difficulties arising from this structure are resolved by constructing an appropriate auxiliary system, and the control problem of the cascaded system is solved via the actuator dynamics compensation method.An error-based observer is constructed to simultaneously estimate external disturbances and system states, and a full-state feedback law is successfully designed to achieve the performance output tracking of the system. Finally, it is proven that the designed observer is well-posed and the resulting closed-loop system possesses exponential stability.