Skip to main content
Fig. 2 | Journal of NeuroEngineering and Rehabilitation

Fig. 2

From: Evaluation of an exercise-enabling control interface for powered wheelchair users: a feasibility study with Duchenne muscular dystrophy

Fig. 2

The control interface of MOVit 2.0. a The movement of the MOVit arms (green area) is controlled using the measured interaction force (\(F_{int}\)) as input of an admittance model that simulates the dynamics of a virtual mass-spring-damper system. The admittance model outputs a reference velocity (\({\dot{x}}_{ref}\)) that is sent to the low level PID controller of the actuator. The movement of the powered wheelchair (blue area) is controlled using the reference velocity (\(\dot{x}_{ref}\)) and the driving mode as inputs. The user can choose between the two driving modes (forward/reverse) by pressing the manual switch of the handle, which acts as a virtual clutch. In the forward mode, only the positive reference velocity will pass, and in the reverse mode, only the negative reference velocity will pass. The output (\(\dot{x}_{in}\)) is then filtered by a low pass filter that smooths out the input signal for the powered wheelchair (\(x_{ref}\)), which mimics the input signal of a 1 DOF joystick where the joystick displacement is proportional to speed. Note that each MOVit arm controls the velocity of its corresponding wheel and that for simplicity this diagram shows only the control diagram of the right side. b Illustrative signals of the reference velocity (\(\dot{x}_{ref}\)), output of the virtual clutch (\(\dot{x}_{in}\)), and reference position (\(x_{ref}\), which is proportional to the wheel velocity) for straight driving, spinning in place, and left turning

Back to article page