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Two common rehabilitation therapies for individuals possessing neurological conditions are functional electrical stimulation (FES) and robotic assistance. This paper focuses on combining the two rehabilitation strategies for use on the biceps brachii muscle group. FES is used to elicit muscle contractions to actuate the forearm and a rehabilitation robot is used to challenge the muscle group in its...
This paper proposes a novel technique for the real-time estimation of the joint torques variations in humans while performing heavy manipulation tasks. To achieve this, the method is based on the deviations of the Centre of Pressure (CoP) and Ground Reaction Force (GRF) in the presence of interaction forces. The CoP and GRF variations are calculated from the difference between the estimated values...
The improvement of movement smoothness over the course of therapy is one of the positive outcomes observed during robotic rehabilitation. Although movements are generally robust to disturbances, certain perturbations might disrupt an individual's ability to produce these smooth movements. In this paper, we explore how a rehabilitation robot's inherent dynamics impact movement smoothness during pointing...
This paper presents the design, mathematical model, and evaluation of a novel variant of a variable stiffness actuator. The actuator combines a cam and a variable lever mechanism. The lever length changes through the rotation of the follower and results in the change of the mechanism stiffness. The design of the actuator results in a nearly linear torque-deflection characteristic, earning it its name:...
Torque limiters are a proven way to enhance the safety in robots. To further increase the safety, adjustable torque limits depending on the task and the joint configuration (joint angles, velocity, acceleration) would be preferable. Friction clutches can be used as adjustable torque limiters (ATL). In contact free motion the ATL can be set with torque limits higher than the required torque, thereby...
The purpose of this research is to propose a design of a clinically relevant upper-limb (hand, wrist, and elbow) exoskeleton that meets the clinical requirements. At first, the proposed robot was designed to have sufficient torque for passive exercise therapy and spasticity measurement of post-stroke patients with spasticity (grade 3 or lower in Modified Ashworth Scale). Because the therapy of patients...
This paper presents design of a novel modular lower-limb gait exoskeleton built within the FP7 BioMot project. Exoskeleton employs a variable stiffness actuator in all 6 joints, a directional-flexibility structure and a novel physical humanrobot interfacing, which allows it to deliver the required output while minimally constraining user's gait by providing passive degrees of freedom. Due to modularity,...
Functional electrical stimulation (FES) is a promising solution for restoring functional motion to individuals with paralysis, but the potential for achieving full-arm reaching motions with FES for various desired tasks has not been realized. We present an open-loop controller capable of calculating and applying the necessary muscle stimulations to hold the wrist of an individual with high tetraplegia...
In this paper we present the design of a one degree of freedom assistive platform to augment the strength of upper limbs. The core element is a variable stiffness actuator, closely reproducing the behavior of a pair of antagonistic muscles. The novelty introduced by this device is the analogy of its control parameters with those of the human muscle system, the threshold lengths. The analogy can be...
There are estimated to be approximately 3.5 million disabled people in Japan, and about half have a handicapped lower or upper limb. Recently, exoskeletons have been receiving attention as potential aids for such individuals. They can make up for lost body muscle, and support walking and standing-up motions. Robots can assist disabled people by using the power of an actuator to provide the force needed...
In this paper, we focus on the strength of a flat bar made of the aluminum alloy in expansion kit TETRIX of LEGO MindStorms, in order to design and manufacture a demonstration equipment for an automatic control theory. The tensile and bending tests were carried out to investigate the mechanical properties of the flat bar. And, the strength design of the demonstration equipment was discussed when the...
Using compliant joints and haptic feedback are two methods that could improve next-generation teleoperated systems, but both methods present challenges to traditional control systems. This paper describes the first experimental investigation of a new approach to real-time haptic control for teleoperated robots with compliant joints. One original aspect of the approach is using an auxiliary error,...
Studying human motor control requires innovative engineering solutions including robots. For example, the motor control task(s) must be reliable before using system identification (SYSID) tools to estimate any motor control descriptors, e.g. neurophysiological parameters. Robots can improve the experiment reliability in contrast to passive devices, e.g. seated balance on a hemisphere. First, we present...
The main impetus for the development of bioinspired robotic technologies stems from their applications to some tasks which require a safe interaction with human beings, e.g., during rehabilitation exercises. In this context, this work presents the mechatronic design and the tracking control of a robotic exoskeleton actuated by biomimetic and soft actuators. The exoskeleton can perform some tasks of...
A motor is designed and tested for the MIT Robotic Cheetah project. The robot presents unique motor design challenges as it contains eight separate motors with different drive cycles, each consisting of short duration large torque commands followed by periods of lesser torque requirement. The ratio between maximum torque and rated torque is approximately 10:1. A design was selected through use of...
Feedforward control is widely used in industrial robot as a valid control method. High speed motion will bring the vibration for robot with flexible joints, which will affect the dynamic performance of robot. The residual vibration character is analyzed for palletizing robot using feedforward control method in this paper. Considering the vibration suppression constraints polynomials fitting method...
This paper presents a novel multi-axis robotic platform for the characterization of two important neuromuscular properties of the human ankle: mechanical impedance and reflex responses. The platform is capable of producing highly accurate position perturbations up to an angular speed of 200°/s and emulating a wide range of haptic environments in two degree-of-freedom (DOF) of the ankle: dorsiflexion-plantarflexion...
Low back pain is one of the world's most serious health problems. Conservative methods are recommended for back pain, and stabilization exercise as one of these methods has been proven to be effective. The “big 3” exercises are proven stabilization exercises, and it is able to train most of the muscles associated with low back stability. However, they are hard to be performed by some patients because...
A wheeled inverted pendulum cannot balance without control, and it is important to save motion in a control range. In some situations, however, to avoid a collision, the maximum acceleration and deceleration must be applied. A motion-planning method for a wheeled inverted pendulum (“body” hereafter)-which uses full performance from all attitudes under hardware constraints-was developed. The developed...
This paper presents the static and dynamic modeling for a recently discovered artificial muscle-twisted and coiled actuator (TCA). This actuator can generate large force and displacement; moreover, it is low-cost, easy to fabricate, and customizable. Since the discovery of TCA, it has been widely adopted for various robotic applications. Nevertheless, theoretical models to describe the static performance...
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