Automating the hand manufacturing chamfering process with traditional robotics is a good approach to achieve precise and consistent results. The use of a vision system to scan the chamfering tool and the prism can help to determine the roundness and position of the tool and the prism, which is crucial for achieving parallelism between them. The use of a laser displacement sensor to verify the position of the prism is also a good approach for ensuring that the prism is correctly positioned.

The cascaded servo loop approach you suggested is a good way to maintain a constant force on the prism and to ensure that the pressure is evenly exerted along the entire edge. However, it is important to make sure that the force applied is not too high, as this could cause the prism to break or run off the edge of the disk. To prevent a runaway condition, you can add logic to detect when the force exceeds a certain threshold and to stop the process if this happens.

Regarding the system block diagram and the cascade force feedback control loop, they look good and provide a clear representation of the process. However, it would be helpful to include more details about the specific sensors and actuators used in the system, as well as any software or control algorithms used to control them. Additionally, it may be helpful to include a description of how the system will be calibrated and validated to ensure that it produces accurate and consistent results.