Exoskeleton robot control based on cane and body joint synergies

Abstract

Several methods have been investigated and realized for operation of exoskeleton robots for assistance of human gait. These systems perform motion intention estimation using the bioelectrical signals of muscle activation, body gestures and kinesiological information, or a mixed combination in a hybrid system. For motion intention estimation of the lower limb(s), information of the lower limbs is usually utilized. However, human gait is not only the function of the lower limbs, but also coordination between upper and lower limbs, adding to balance and cognitive functions as well. In this study, we investigate on how to utilize the synergies of upper and lower limbs of human walking in exoskeleton robot control by using the cane (walking aid). We analyse the synergies of human gait with cane in healthy subjects by means of Principal Component Analysis (PCA) in order to investigate the usability of cane for robot-assisted motor rehabilitation. We also implement a semi autonomous control for an exoskeleton robot, single leg version of HAL (Hybrid Assistive Limb) suit, based on the cane and body joint synergies.

Inverse Modeling of Human Knee Joint Based on Geometry and Vision Systems for Exoskeleton Applications

“…The Japanese company Cyberdyne is worldwide known for the development of the HAL (acronym for hybrid assistive limb) exoskeleton [12], which is used for either task support, rehabilitation, or welfare applications. The HAL robot has been extensively studied, for example, the synchronization control that is based on the position change of the center of ground reaction force (CoGRF) by Tsukahara et al [12], which later added a speed estimator to this control model [13], or the work presented by Hassan et al [14] that included the application of HAL control that is based on combining both lower and upper limb pose signals. Furthermore, the Indego exoskeleton is another good example of commercial devices [15] that are based on the Vanderbilt exoskeleton [5] and is a powered lower limb orthosis for ground gait training.…”

Development and control of a one-wheel telescopic active cane

“…Again during the double stance phase, the cane remains at rest until the beginning of the weak leg swing. Note that this strategy is in accordance with [7] where the authors take advantage of the synergy between the cane and the legs motion to control a HAL Exoskeleton.…”

Wearable Gait Measurement System with an Instrumented Cane for Exoskeleton Control

“…Figure 5 illustrates the signal flow of the control system at this state. Motion of the affected leg's hip and knee joints are estimated from the motion of the cane and the motion of the unaffected leg's hip and knee joints (all motions are angle and angular velocities in the sagittal plane), as in Equation (8) $x_2={\mathrm{normal\Gamma }}_2{\mathrm{normal\Gamma }}_1^{\#}{x}_1$where x 2 are the variables to be estimated: affected leg's hip and knee angles and angular velocities, x 1 are the known variables: cane and unaffected leg's hip and knee angles and angular velocities, and ${\mathrm{normal\Gamma }}_2{\mathrm{normal\Gamma }}_1^{\#}$ is the rearranged matrix of the eigenvectors extracted from walking with cane trials of seven healthy subjects [30], and rearranged for estimation of x 2 from x 1 [31]. The estimated trajectories are streamed to the robot, and tracked with the actuators on the robot's hip and knee joints with PD controllers.…”