Real-time collision avoidance in teleoperated whole-sensitive robot arm manipulators

Abstract

In traditional teleoperation systems, the human operator is saddled with two distinct tasks: I) moving the robot arm to its desired position, a nd 2) avoiding obstacles that can obstruct the arm motion. The current robot teleopera tion research concentrates on providing the operator with as much input information about the task site as possible using, for example, stereo vision or contact force feedback. These methods presume that the operator is capable of planning motion for the entire body of the robot in a cluttered environment. Studies show, however, that the operators, first, cannot address both tasks in real time, and second, are not good at generating collision-free motion in a complex environment. Recent results in sensor-based motion planning suggest that the collision avoidance task can be handled automatically, thus freeing the operator for global control. To this end, it is also proposed to use whole-sensitive arm manipulators whose whole bodies are covered with a sensitive skin sensor to detect nearby objects. The data from the skin is processed by motion planning algorithms, to avoid collisions for the entire a rm body in an unknown or time-varying environment. The motion of the operator-controlled master arm is either repeated faithfully by the slave arm, or, to avoid collisions, is used as general guidance. In the latter case the slave arm attempts to be as close as possible to the positions commanded by the operator, without jeopardizing its safety. The result is an efficient, safe and robust hybrid system in which integration of control by the operator a nd the automatic system is done transparently and in real time.

Collision Detection and Safe Reaction with the DLR-III Lightweight Manipulator Arm

“…with σ(0) = 0, k D > 0, and where E(t) is the total robot energy at time t ≥ 0, as defined in (3). Note that σ can be computed using the measured joint position q and velocityq (possibly obtained through numerical differentiation) and the commanded motor torque τ .…”

“…Along a similar but simpler line, robot manufacturers are providing hw/sw facilities for prescribing safe Cartesian areas that should not be accessed by the robot in any operative condition. Anticipating incipient collisions or recognizing them in real-time is typically based on the use of additional external sensors, such as sensitive skins [3], onboard vision [4], strain gages, force load cells, and so on.…”

Real-Time Obstacle Avoidance for Telerobotic Systems Based on Equipotential Surface

“…According to the 3D data of the environment, the potential field of obstacle on the equipotential surface can be obtained by shell. 1  and 2  represent the influence distance of the potential field influence to avoid undesirable disturbance when the obstacle approaches, and hence they form two envelopes, as shown in Figure 8. Thus, there is a double layers protection for the arm.…”

“…The normal robotic control need path planning automatically, while the path of telerobot is planned by the command information provided by human operator. In general telerobotic systems, the human operator is saddled with two basic tasks: 1) moving the robot arm to its desired position, and 2) avoiding obstacles collide with the telemanipulator [1]. Practically, when disposing a grasping task by redundant telerobotic systems, human operator only focuses attention on the end-effector to track the command trajectory, while movement of other links of manipulator are usually ignored and in unsupervised situation.…”

Surface differentiation by parametric modeling of infrared intensity scans

“…9 IR sensors are used in robotics and automation, process control, remote sensing, and safety and security systems. More specifically, they have been used in simple object and proximity detection, 10 counting, 11 distance and depth monitoring, floor sensing, position measurement and control, 12 obstacle and collision avoidance, 13 and map building. 14 IR sensors are used in door detection and mapping of openings in walls, 15 as well as monitoring doors and windows of buildings and vehicles, and ''light curtains'' for protecting an area.…”