The sensors and actuators used should be limited to those currently available on a modern loading machine.
In this case, the number of configuration variables is greater than the number of actuators during single support or flight phases.
No brake is used so the negative work must be produced by the actuators.
However, enough capacity of actuators cannot be selected in most robot manipulators since the actuating motors of robot manipulators are serially placed on links.
In designing dynamic systems, actuators with enough torque capacity are selected to fully actuate the systems.
Interesting examples are given by under-actuated grippers or hands, which are defined as those with more d. o. f. s than actuators.
During the single support phase, the configuration of the biped is defined by five independent variables, but there are only four actuators.
In this case, embedded intelligence is associated to several actuators and sensors.
