The overall objective of the project is to develop and validate an integrated methodology to design intelligent robotic assistive devices and to test these devices in clinical conditions.

The integration relates to all aspects of such devices and their interaction with humans: engineering aspects (mechatronic design, intelligent control, and simulation), physiological and clinical aspects, and psychological aspects.

Methodologies and new technologies related to all of these aspects will be developed and applied to one challenging application: a bilateral active lower-limb exoskeleton to assist persons with functional weakness.

The following objectives were set out in order to achieve the overall research objective.

Objective 1:

Analyze and demonstrate the advantages of a variable impedance actuator (e.g. the MACCEPA drive) concept in view of energy efficiency, wearability and safety in human-robot interaction.

Objective 2:

Develop and demonstrate a high-level control approach for the interaction between medical devices (e.g. prostheses and orthoses) and humans, and in particular for the application of the assistance-as-needed concept.

Objective 3:

Develop a simulation environment to study the dynamic interaction between actuated devices and humans.

Objective 4:

Develop a procedure to inventory the patients’ psychological perception of the desired and undesired aspects and criteria of assistive devices.

This procedure is applied to the case of the bilateral lower-limb exoskeleton to provide input at the design stage and to evaluate the actual prototypes.

Objective 5:

Design and build a bilateral lower-limb exoskeleton to apply and demonstrate objectives 1-2.

The exoskeleton has seven active degrees of freedom, including ankle plantarflexion/dorsiflexion, knee flexion/extension, hip flexion/extension, and pelvic rotation, and has additional passive degrees of freedom. It cooperates with the human and provides assistance, is wearable and adaptable to an individual user, and remains clinically relevant for elderly and functionally weak patients (see objective 6).

Objective 6:

Support and verify objectives 1, 2 and 5 by clinically testing the bilateral lower-limb exoskeleton.

Four target user groups are selected: adults with functional weakness including (1) elderly with functional weakness, (2) MS-patients and (3) stroke patients, and (4) CP-children. The focus with elderly is primarily on force assistance. Target groups 2-4 are more involving due to a greater variability and the occurrence of spastic motions. The aim is to facilitate walking, and this is tested in different stages, i.e. for different functions, as subsequent, more versatile versions of the exoskeleton become available during the project: 1) stand up – balance – sit down; 2) step forward – step back, first quasi-statically, then dynamically; 3) walk – accelerate – decelerate – take a turn; 4) cope with uneven terrain; 5) use human intention estimation to select the appropriate assistance mode and its control parameters. Particular attention will be paid to the rehabilitation capabilities of the assistance-as-needed approach.