Articulated robot

About: Articulated robot is a research topic. Over the lifetime, 4364 publications have been published within this topic receiving 52442 citations.

Lead-through robot teaching

Abstract: This paper presents a lead-through method and device for industrial robots and more particularly the design and calibration of a portable lead-through teaching device. Most industrial robots are programmed by a teach-and-playback approach. In some applications, maneuvering robots using the joystick or keypad on the teach pendant along the desired path is not easy or intuitive. To solve this problem, lead-through teaching methodologies have been developed by researchers from both academia and industries for more efficient and intuitive teaching of discrete point or continuous-path robot programs. We developed a portable lead-through teaching device, which is designed to be calibrated by moving the device to predetermined reference poses.

Online approach for altering robot behaviors based on human in the loop coaching gestures

Abstract: The creation and adaptation of motor behaviors is an important capability for autonomous robots. In this paper we propose an approach for altering existing robot behaviors online, where a human coach interactively changes the robot motion to achieve the desired outcome. Using hand gestures, the human coach can specify the desired modifications to the previously acquired behavior. To preserve a natural posture while performing the task, the movement is encoded in the robot's joint space using periodic dynamic movement primitives. The coaching gestures are mapped to the robot joint space via robot Jacobian and used to create a virtual force field affecting the movement. A recursive least squares technique is used to modify the existing movement with respect to the virtual force field. The proposed approach was evaluated on a simulated three degrees of freedom planar robot and on a real humanoid robot, where human coaching gestures were captured by an RGB-D sensor. Although our focus was on rhythmic movements, the developed approach is also applicable to discrete (point-to-point) movements.

Hiding robot inertia using resonance

Abstract: To enable compliant training modes with a rehabilitation robot, an important prerequisite is that any undesired human-robot interaction forces caused by robot dynamics must be avoided, either by an appropriate mechanical design or by compensating control strategies. Our recently proposed control scheme of “Generalized Elasticities” employs potential fields to compensate for robot dynamics, including inertia, beyond what can be done using closed-loop force control. In this paper, we give a simple mechanical equivalent using the example of the gait rehabilitation robot Lokomat. The robot consists of an exoskeleton that is attached to a frame around the patient's pelvis. This frame is suspended by a springloaded parallelogram structure. The mechanism allows vertical displacement while providing almost constant robot gravity compensation. However, inertia of the device when the patient's pelvis moves up and down remains a source of large interaction forces, which are reflected in increased ground reaction forces. Here, we investigate an alternative suspension: To hide not only gravity, but also robot inertia during vertical pelvis motion, we suspend the robot frame by a stiff linear spring that allows the robot to oscillate vertically at an eigenfrequency close to the natural gait frequency. This mechanism reduces human-robot interaction forces, which is demonstrated in pilot experimental results.

Programming by demonstration by optical tracking system for dual arm robot

Abstract: In this paper, a PbD (Programming by Demonstration) experiment platform is setup based on a dual arm robot and an motion tracking system A PbD method based on optical tracking system is implemented and tested on this platform This method uses motion tracking sensor to capture operator arms motion and then let robot to imitate operator arm motion At the same time, robot motion is logged, optimized and the robot program is generated automatically by a computing device or the robot controller itself It can speed up robot programming and reduce the learning difficulty of robot programming greatly by just demonstrating action sequences to robot, and furthermore, it can save investment for dual arm robot or multi robot programming by reducing tailored fixtures It is very easy to use for a process expert who knows a little about robot The advantage of this method is that it can program more than one robot at the same time and can reduce robot programming difficulty This method especially fits for dual arm robot and multi robot cooperation programming, but it also can be used for single arm robot Experiment result shows that robot can follow operator's motion accurately and the time delay is acceptable for some application such as teaching, so it's feasible to apply PbD method on industrial robot

The safe control of human-friendly robots

Abstract: Introduces an approach to the control of robot manipulators in a way that is safe for humans in the robot's workspace. Conceptually the robot is viewed as a tool with limited autonomy. The limited perception capabilities of automatic systems prohibits the construction of failsafe robots with the capabilities of people. Instead, the goal of our control scheme is to make the interaction with a robot manipulator safe by making the robots actions predictable and understandable to the human operator. At the same time the forces the robot applies with any part of its body to its environment have to be controllable and limited. Experimental results are presented of a human-friendly robot controller that is under development for a Barrett Whole Arm Manipulator robot.