In the process of accurately tracking the welding path with the end effector of an industrial robot arm, challenges such as joint friction (disturbance) and communication time delay arise. To address these issues, this study investigates the performance output tracking problem for a one-dimensional unstable heat equation, with unknown external disturbances and input end 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, where the transport equation represents the actuator dynamics. The system features a non-collocated structure, where the difficulties arising from this structure are resolved by constructing an appropriate auxiliary system. 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. It is proven that the designed observer is well-posed and the closed-loop system achieves exponential stability.