Movement assistance apparatus, e.g., for feeding, writing

An apparatus comprising:

• a main arm having links extending from a ground end to an effector end and allowing movement of the effector end from a first position to a second position, the links including at least a base link adapted to be pivotally connected to a base, and a spacing link pivotally mounted to a free end of the base link and extending to the effector end;
• a first 4-bar parallelogram having pivot joints at its corners and including the base link of the main arm;
• a second 4-bar parallelogram having pivot joints at its corners and including the spacing link of the main arm and an effector link at the effector end adapted to support an object;
• a serial interconnection between the first 4-bar parallelogram and the second 4-bar parallelogram constraining the effector link to maintaining a constant orientation in at least two rotational degrees of freedom relative to the base;
• and
• a drive link assembly between the spacing link of the second 4-bar mechanism and the base, the drive link assembly including a first drive link pivotally connected to the base and a second drive link pivotally connected to the first drive link, the second drive link pivotally connected to the spacing link.