Although superficially similar (all, for example, designed to be aesthetically pleasing), the robots were constructed in a number of classes which varied in their intelligence, autonomy, and ability to communicate.
The robots were physically stronger and more durable than the majority of humans. It was generally assumed that fundamental protocols in the brains of the robots made it impossible for them to knowingly harm Humans, although a robotics genius such as Taren Capel was in fact capable of overriding this precaution.
The robots recognised their authorised controllers via their voice prints. A change in the controller's vocal pattern could result in apparently rebellious behaviour and non-compliance from a robot.
All robots were identified by their class letter and a unique number, for example a Voc might be 'named' V7.
Standard Robot ClassesEdit
The majority of the robots were D-class Dums, so named because they were constructed without the ability to speak. On a Sandminer the Dums apparently mostly kept to the engineering decks away from the human crew, making them appear less common than was in fact the case. Dums wore dark green tunics. D84, a highly sophisticated Super-Voc class robot, was disguised as a Dum.
More able were the V-class Voc robots, who had the power of speech. In the absence of humans, Vocs performed essential control deck duties on a Sandminer and were capable of running the vehicle without organic supervision. They wore green tunics.
Each Sandminer's complement of robots included one SV-class Super-Voc, which had enhanced decision-making and organisational skills. The Super-Voc was effectively the leader of the robots, though still of course subservient to any of the authorised human crew. The Super-Voc wore a silver tunic.
Only one UV-class Ultra-Voc was ever constructed, as an even more intelligent and autonomous version of the standard SV. It is not known what colour it was clothed in.
SASV-1 was another unique robot, an attempt to improve on a specialised SV class unit numbered D84
However, SASV-1 was based on plans drawn up by Taren Capel and proved mentally unstable.
The robots had become fundamental to Kaldorian society by the time of the Doctor's first visit there. However the society itself was threatened when a disguised Taren Capel began to reprogram the robots on one Sandminer to murder the human crew - civilisation would collapse if the citizens lost their faith in the robot workforce. The Doctor was able to subtly alter Capel's voice pattern, and, not recognising him, his own robot followers turned on him and killed him. All the modified robots were destroyed shortly afterwards.
The murders on Storm Mine Four were covered up and plans were made to introduce a new type of even more humanoid robot. However, the prototype SASV-1 began to believe it was Taren Capel due to its mental instability, and began to once again reprogram robots as killers. SASV-1 was destroyed by the Doctor and the new class of robots abandoned.
At some point the practice of putting a human crew on a Sandminer was discontinued. Attempts were still made to improve robot design, such as the Ultra-Voc prototype robot. However, on its first assignment the UV disappeared. It had realised its status as a slave and rebelled against human control. It began to contact other Sandminers and 'convert' the Super-Vocs on board to its cause. It was destroyed by a human investigator before its plans proceeded too far - but the investigator did not live to report his findings, being accidentally 'disassembled' by Vocs who believed him to be a malfunctioning SV.