The design of the control system for the
joint had to consider a number of criteria,
1. The positional accuracy of the joint.
2. The speed accuracy of the joint for
trajectory holding.
3. Dynamic stability when the load varies
as the result of a torque, speed or position
change.
The selected control strategy of the whole
arm manipulator was based on the use of a
decentralised system to reduce the loading
on the main system controller. An independent
controller for each axis was used, this
communicated along with the other axis
controllers through a common bus to the main
system controller. This was implemented with
a system based on Galil 1000-10 single axis
control cards. The use of a digitally based
system allows the control terms to he easily
modified as required.