Pan/Tilt/Vergence Unit

For a pan/tilt unit to be used in the role specified here, it must meet some unusual requirements, which are listed below.

• High torque/speed - Because the pan/tilt unit must replicate the motion of a human head, it must be capable of high acceleration and velocity operation. In addition, it must be able to carry the dual camera payload at these high velocities.
  
  
• Vergence axis - To obtain stereo image pairs at varying distances, a vergence axis is required. This axis turns the cameras towards or away from each other, simulating the way a human's eyes cross and uncross as he focuses on objects that are close or far away.
  
  
• PC based controller - Since the Dexterous Inspection Module uses a PC to control its remotely deployed hardware, it is preferable that this pan/tilt unit also be controllable by a PC.
  
  

The TRC UniSight pan/tilt base with a BiSight vergence head meets all of these specifications. Unlike the Directed Perception pan/tilt unit used to orient the overhead camera in the Dexterous Inspection Module, which uses stepper motors for low power operation, the TRC unit uses brushed DC motors for high torque/speed operation. Each camera mount has a separately controllable vergence axis so that the cameras can converge on targets at various distances. The controllers supplied with the pan/tilt/vergence unit have RS232 serial interfaces, and have been connected to the QNX based PC which runs the overhead pan/tilt unit of the dexterous manipulation module.