LOPES II—Design and Evaluation of an Admittance Controlled Gait Training Robot With Shadow-Leg Approach

Abstract

Robotic gait training is gaining ground in rehabilitation. Room for improvement lies in reducing donning and doffing time, making training more task specific and facilitating active balance control, and by allowing movement in more degrees of freedom. Our goal was to design and evaluate a robot that incorporates these improvements. LOPES II uses an end-effector approach with parallel actuation and a minimum amount of clamps. LOPES II has eight powered degrees of freedom (hip flexion/extension, hip abduction/adduction, knee flexion/extension, pelvis forward/aft and pelvis mediolateral). All other degrees of freedom can be left free and pelvis frontal- and transversal rotation can be constrained. Furthermore arm swing is unhindered. The end-effector approach eliminates the need for exact alignment, which results in a donning time of 10-14 min for first-time training and 5-8 min for recurring training. LOPES II is admittance controlled, which allows for the control over the complete spectrum from low to high impedance. When the powered degrees of freedom are set to minimal impedance, walking in the device resembles free walking, which is an important requisite to allow task-specific training. We demonstrated that LOPES II can provide sufficient support to let severely affected patients walk and that we can provide selective support to impaired aspects of gait of mildly affected patients.

Effects of a neuromuscular controller on a powered ankle exoskeleton during human walking

“…We wish to test this further by extending the neuromechanical models of human locomotion to account for specificity of spinal cord injury subjects and test the derived controllers in simulation, on existing devices (e.g. Achilles and gait trainer LOPES [14]), and on a novel exoskeleton currently under development within the framework of the Symbitron project.…”

An Adaptive Neuromuscular Controller for Assistive Lower-Limb Exoskeletons: A Preliminary Study on Subjects with Spinal Cord Injury

“…Sensory input into NMC include stance state, hip angle, and knee angle for both legs. LOPES figure based on Meuleman et al (2016). …”

“…The haptic gait trainer LOPES (Figure 1B, see Meuleman et al, 2016, for details) consists of shadow legs that help move the subject and a treadmill. The subject is provided body weight support through a harness and is also attached to the device at the waist and at the shank with leg clamps.…”

“…Active degrees of freedom include shank flexion/extension, thigh flexion/extension and hip abduction/adduction. LOPES can impart up to 70 N-m of knee torque and hip torque (Meuleman et al, 2016), within range of biological torques and therefore able to move the lower limbs of a fully paralyzed subject. The pelvis can also be moved in the forward/aft direction and in the frontal plane.…”

A New Directional-Intent Recognition Method for Walking Training Using an Omnidirectional Robot

“…However, current designs are difficult to put on and pose a danger of the user falling. Other kinds of wearable gait-training robots are popular because they can physically support the limbs during therapy and allow a more seamless transition between assistive and resistive rehabilitation as the patient progresses [13,14]. However, these devices are expensive, cannot traning the balance of walking for users, and are only available in a restricted number of clinical or rehabilitation centers [15].…”