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This paper presents the mechatronic design and experimental validation of a novel powered knee-ankle orthosis for testing torque-driven rehabilitation control strategies. The modular actuator of the orthosis is designed with a torque dense motor and a custom low-ratio transmission (24:1) to provide mechanical transparency to the user, allowing them to actively contribute to their joint kinematics...
This video presents an overview of the hardware and control applications of the TOrque-controlled humanoid RObot TORO developed at DLR. The self-contained robot was developed as a research platform for walking and whole-body control. It is based on the drive units of the DLR-KUKA Lightweight Robot Arm (LBR) III, has a total of 39 DoF, and it can be operated both in position and torque control modes...
We discuss a feedback controller to stabilize biped walking which has toe support phase mimicking human gait. Using a reference walking pattern proposed in our previous work [11], our stabilizer can realize reliable walking. To evaluate the quality of stabilization, we propose two indicators, the maximum floor reaction force and the root mean square of the CoM tracking error. From our walking experiments,...
We propose a balancing control framework for a torque-controlled biped robot, Roboray. Roboray has two 6 DOF legs and torque sensors are integrated at all the leg joints. It has a new cable-driven joint module as a pitch joint drive, which is highly back-drivable and elastic. Using these hardware characteristics, we propose a new balancing control algorithm. This algorithm is the combination of gravity...
In wearable robotics applications, actuators are required to satisfy strict constraints in terms of safety and controllability. The introduction of intrinsic compliance can help to meet both these requirements. However, the high torque and power necessary for robotic systems for gait assistance requires the use of custom elements, able to guarantee high performances with a compact and lightweight...
Biped robot requires a control system to ensure the stability of the robot during walking. Computed torque control approach is a special application of feedback linearization of nonlinear system which also appears in robust control, adaptive control, learning control, and so on. This paper first introduces a newly designed mechanism, an 8 degree of freedom (DOF) biped robot, which designed in SolidWorks...
This paper gives an overview of the development of a novel biped walking machine. The robot is designed as an experimental system for studying biped locomotion based on torque controlled joints. As an underlying drive technology, the torque controlled joint units of the DLR-KUKA-Lightweight-Robot are employed. The relevant design choices for using this technology in a biped robot with integrated joint...
Humans are able to robustly maintain balance in the presence of disturbances by combining a variety of control strategies using posture adjustments and limb motions. Such responses can be applied to balance control in two-armed bipedal robots. We present an upper-body control strategy for improving balance in a humanoid robot. Our method improves on lower-body balance techniques by introducing an...
The new technology advances have allowed us the design and construction of sophisticated artificial legs, which give a very close to normal human gait to patients that have received these devices. But the task is very difficult, and it requires a lot of research with interdisciplinary-science teams. One of the tools which lets to get excellent artificial legs is the study and design of biped robots,...
The gait stability of Passive Dynamic Walking is sensitive to the initial walking state, which must be adjusted precisely for continuous gaits. A novel torque shaping control method is proposed to obtain the initial stable gait for the passive dynamic walker within a gait period in this paper. Meantime, the stability of the system with this controller is proved. Therefore, the unstable initial state...
Model-based control methods can be used to enable fast, dexterous, and compliant motion of robots without sacrificing control accuracy. However, implementing such techniques on floating base robots, e.g., humanoids and legged systems, is non-trivial due to under-actuation, dynamically changing constraints from the environment, and potentially closed loop kinematics. In this paper, we show how to compute...
The redundant driving problem is an inherent phenomenon existing in a modular caterpillar robot. To limit the internal forces arising from the redundant driving, this paper proposes a joint torque control method, which is based on an assumption that there is only one active joint in the four-link mechanism driving the climbing gait. Except the active joint, the other three joints are all considered...
Rotation is one of efficient transportation method for big or heavy object. For implementing the rolling operation to the small and light weight robot, the friction control is necessary considering its movable range, balance and actuator power. In this paper, we propose a new rolling manipulation by using whole body motion for multi-legged robot. The weight shift control is implemented considering...
The secondary regulation hydrostatic transmission technology is applied to the wheel excavator walking device to improve the fuel economy and emissions. A new braking control strategy is proposed based on the analysis of the characteristics of excavator braking and high power density of hydrostatic transmission technology. As to deal with the robust control problems against parameter uncertainty and...
The MACCEPA (Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator) is an electric actuator of which the compliance and equilibrium position are fully independently controllable and both are set by a dedicated servomotor. In this paper an improvement of the actuator is proposed where the torque-angle curve and consequently the stiffness-angle curve can be modified by choosing...
Ankle-foot orthoses (AFOs) are orthotic devices supporting movements of ankles of disabled persons for example hemiplegia, polio, peroneal nerve palsy, etc. In our previous research, we developed some kinds of passive controllable AFO which can control ankle torque with Compact Magnetorheological fluid brakes. One of the remarkable key points of its control is damping control at initial contacts....
We call such a model consists of two rigid rods connected by a frictionless hinge at the hip, a compass-like model. In this paper, we consider a compass-like model in order to analyze biped robot motion. We are trying to control gait of the model, by inputing torque to the hinge of the hip, and show that the maximal torque input can be reduced by using a mechanism to constrain the angle of the hip...
This paper presents a self-contained powered knee and ankle prosthesis, intended to enhance the mobility of transfemoral amputees. A finite-state based impedance control approach, previously developed by the authors, is used for the control of the prosthesis during walking and standing. Experiments on an amputee subject for level treadmill and overground walking are described. Knee and ankle joint...
The biped Lucy, powered by pleated pneumatic artificial muscles, has been built and controlled and is able to walk up to a speed of 0.15 m/s. The pressures inside the muscles are controlled by a joint trajectory tracking controller to track the desired joint trajectories calculated by a trajectory generator. However, the actuators are set to a fixed stiffness value. In this paper a compliance controller...
We extend simple models previously developed for humanoids to large push recovery. Using these simple models, we develop analytic decision surfaces that are functions of reference points, such as the center of mass and center of pressure, that predict whether or not a fall is inevitable. We explore three strategies for recovery: 1) using ankle torques, 2) moving internal joints, and 3) taking a step...
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