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This paper deals with a new CLIE (Closed Loop Input Error) method for dynamic identification of flexible joint robots. This is a straightforward extension of the DIDIM (Direct and Inverse Dynamic Identification Models) method from rigid robots to flexible joint robots. DIDIM is a fast closed loop input error method which minimizes the quadratic error between the actual motor force/torque (the control...
The studies of energy consumption during tripod gait of six-legged walking machines are presented. The method used for energy evaluation is outlined and the results are presented. The energy consumption during support phase, which is the most demanding phase, is analyzed. The energy consumption is expressed in the normalized form, depending on the normalized leg proportions, body height and step length...
Twisted string actuator is a compliant, light, and mechanically simple module. The actuation principle is based on the contraction of the strings, where a low torque - high speed dc motor is capable of providing high forces. Such actuators are very light, quiet, compliant, mechanically simple and provide a possibility to move motors away from the actu- ating joint. Implementation of these actuators...
In the past 20 years, control methods for two-inertia systems have gradually changed from semi-closed control to full-closed control in order to achieve higher precision positioning. Though there is a trend toward the expansion of the use of load-side encoders in the industry, we can hardly say that control methods using load-side information are sufficiently studied. This paper proposes a novel joint...
sEMG (surface electromyography) signals have been used as human-machine interface to control robots or prostheses in recent years. sEMG-based torque estimation is a widely research methodology to obtain human motion intention. Most researches focus on improving the accuracy of sEMG-torque models, which often makes them complicated and confined in the laboratory research. However, an accurate estimation...
This paper presents a myoelectric control of an arm exoskeleton designed for rehabilitation. A four-muscles-based NeuroMusculoSkeletal (NMS) model was implemented and optimized using genetic algorithms to adapt the model to different subjects. The NMS model is able to predict the shoulder and elbow torques which are used by the control algorithm to ensure a minimal force of interaction. The accuracy...
The biological of spider legs inspired the development of a biomimetic pneumatic actuator for robotic applications. The concept is to straighten the joint by pressurizing the interior of an exoskeleton to inflate a bellows-like flexible membrane. The flexion is initiated by contraction of a McKibben-type muscle, which is integrated in the exoskeleton chamber. A detailed mathematical model to operate...
This paper deals with the design, fabrication and control of an Articulated Robotic Arm which can shadow the movement of a Human Arm by using low cost sensors. In this project, four potentiometers are used to control the motion of the arm while one is used to controls the orientation of the wrist and one more is used for controlling the gripper to form a 5 Degree of Freedom(DOF) Robotic Arm. Servo...
This paper presents an integrated kinematics and dynamic modeling of the swing, hoist, and crowd movements of an electric mining shovel driven by regenerative vector-controlled ac drives through ropes and gear reducers. The shovel is modeled as a 4-DOF articulated mechanical system with three rotating joints and one prismatic joint. Using the developed models, a typical truck loading cycle of digging,...
UAV(Unmanned Aerial Vehicle) has led to a new era of global growth, and interest about UAV has rapidly increasing [1]. The Drone is a type of UAV. In recent years, with the camera mounted on a drone, and it has been used to take a farm, the military, and broadcast video. To shoot an image, it can turn the body of the camera angle and drones, it must be able to tilt. Multi-DOF (degree-of-freedom) system...
Humanoid robot is able to execute various behavior to manipulate objects because of high degree-of-freedom around the whole-body. Although hands contact with objects and exert force in ordinary pushing motion by robot, pushing motion contacting with the object at various regions of whole-body has potential for extending the scope of feasible manipulation. We derive the fundamental formulas of humanoid...
This paper presents a kinematic study of a pseudo-rigid-body model (PRBM) of MRI-compatible, magnetically actuated, steerable catheters. It includes a derivation of a mathematical model of the PRBM of the catheter, singularity studies of the model, and a new manipulability measure. While the forward kinematics of the model presented here is applicable to PRBMs for other applications, actuation method...
Robots are ever more present in human environments and effective physical human-robot interactions are essential to many applications. But to a person, these interactions rarely feel biological or equivalent to a human-human interactions. It is our goal to make robots feel more human-like, in the hopes of allowing more natural human-robot interactions. In this paper, we examine a novel biologically-inspired...
In this paper we introduce STEPPR (Sandia Transmission-Efficient Prototype Promoting Research), a bipedal robot designed to explore efficient bipedal walking. The initial iteration of this robot achieves efficient motions through powerful electromagnetic actuators and highly back-drivable synthetic rope transmissions. We show how the addition of parallel elastic elements at select joints is predicted...
Redundant robots performing multiple tasks of different priority levels are often handled by hierarchical control frameworks. This paper proposes a general hierarchical control approach that can handle not only a single standard lexicographic hierarchy, but also a complex priority network involving both strict and non-strict task priorities. In this approach, priorities can be defined by pairs of...
It has recently been shown that intrinsically elastic robots are capable of outperforming rigid robots in terms of peak velocity by making systematic use of energy storage and release. Certainly, high link side velocities are beneficial for performance, however, they also increase the probability of self damage or human injury in case of a collision. To ensure the physical integrity of both human...
The cycling wheelchair is a new type of mobility aid for lower-limb-disabled individuals. Patients can drive the cycling wheelchair by pressing the front pedals with their lower limbs. The device enables patients to effectively rehabilitate their disabled legs and partake in outdoor activities. However, lower-limb-disabled individuals cannot move both legs with equal ease. Typical hemiplegia patients...
Learning motion tasks in a real environment with deformable objects requires not only a Reinforcement Learning (RL) algorithm, but also a good motion characterization, a preferably compliant robot controller, and an agent giving feedback for the rewards/costs in the RL algorithm. In this paper, we unify all these parts in a simple but effective way to properly learn safety-critical robotic tasks such...
Classically robot force control passes through joint torques measurement or estimation. Within this context, classical torque sensing technologies rely on current sensing on motor windings and on torsion sensing on motor shaft. An alternative approach was recently proposed in [1] and combines whole-body distributed 6-axis force/torque (F/T) sensors, gyroscopes, accelerometers and tactile sensors (i...
This paper presents an adaptive and compliant approach-to-grasp strategy for multi-finger robotic hands, to improve the performance of autonomous grasping when encountering object position uncertainties. With the proposed approach-to-grasp strategy, the first robot finger to experience unexpected impact would pause its movement in a compliant manner, and remains in contact with the object to minimize...
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