Quantity   Component name
3 × PM Field Servo Motor MH3515-228D - The arm has three of these: base rotation, segment 1 actuation and segment 2 actuation. They're from Cleveland Machine Controls.
3 × SUMTAK Differential Linear Encoder LDA-051-1000 - These are the position sensors for the MH3515-228D servo motors.
3 × HP Rotary Encoder HEDS-5310 - These are the position sensors for the servo motors in the arm extremity. Each one is coupled to a 24v DC servo motor.