We describe a new robot architecture: the collaborative robot, or cobot. Cobots are intended for direct physical interaction with a human operator. The cobot can create smooth, strong virtual surfaces and other haptic effects within a shared human/cobot workspace. The kinematic properties of cobots differ markedly from those of robots. Most significantly, cobots have only one mechanical degree of freedom, regardless of their taskspace dimensionality. The instantaneous direction of motion associated with this single degree of freedom is actively servo-controlled, or steered, within the higher dimensional taskspace. This paper explains the kinematics of cobots and the continuously variable transmissions (CVTs) that are essential to them. Powered cobots are introduced, made possible by a parallel interconnection of the CVTs. We discuss the relation of cobots to conventionally actuated robots and to nonholonomic robots. Several cobots in design, prototype, or industrial testbed settings illustrate the concepts discussed.

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Cobots are a class of mechanically passive robotic devices, intended for direct physical collaboration with a human operator. The operator supplies all motive power while the cobot enforces software-defined guiding surfaces, or constraints. Cobots are intrinsically passive, safe devices. This is because, rather than employ powered actuators to produce constraint forces, cobots use "steerable" nonholonomic joints. Constraint forces are mechanical in origin, yet software defined.The simplest possible cobot is a unicycle which is steered by a servo system acting under computer control, but which is movcd by a human operator. The unicycle cobot requires essentially no consideration of kinematics. Two fundamental control modes of the unicvcle cobot.joints whose intrinsic mechanics provide the constraint forces.The essentials of cobot mechanics may be understood by considering the simplest such device, the unicycle cobot shown in Fig. 1. The cobot mechanism consists of a free-rolling wheel in contact with a working surface. The wheel's rolling velocity is monitored by an encoder, but it is not driven by a motor. The motor in the figure simply steers the wheel, and cannot cause the cobot to move. Only the operator can cause it to move, by applying forces to the handle. A handle-mounted force sensor monitors these user forces. The linear rails in the figure are part of a Cartesian frame which supports the cobot upright. These rails arc also instrumcnted with linear potentiometers in order to measure the global Dosition of the cobot. "virtual caster" and "constraint tracking", are reGiewed. 'More complicated cobots, such as the three-wheeled "Scooter", require a set of kinematic transformations relating configuration space to joint space. These transformations play a role in cobot control like that of the jacobian in robot control.

Abstract. Accurate real-time information of wheel slip angle is essential for various active stability control systems. A number of techniques have been proposed to enhance quality of GPS based estimation. This paper exhibits a novel cost-effective strategy of individual wheel slip angle estimation for a rear-wheel-drive (RWD) vehicle. At any slip condition, the slip angle can be estimated using only measurement of steering angle, front wheel rolling speeds, yaw rate, longitudinal and lateral accelerations, without requiring GPS data. On the basis of zero longitudinal slip at the both front tires, the closed-form solutions for direct computation of wheel slip angles were derived via kinematic analysis of a planar four-wheel vehicle, and then primarily verified by computational simulation with prescribed functions of radius of curvature, vehicle speed, sideslip and steering angle. Neither integration nor tire friction model is required for this estimation methodology. In terms of implementation, a 1:10th scaled RWD vehicle was modified so that the steering angle, the front wheel rolling speeds, the vehicle yaw rate and the linear accelerations could be measured. Preliminary experiment was done on extremely random sideslip maneuvers beneath the global positioning using four recording cameras. By comparing with the vision-based reference, the individual wheel slip angles could be well estimated despite extreme tire slip. Other vehicle state variables-i.e., radius of curvature, vehicle sideslip and speed-might be obtained from kinematic relations. This proposed estimation methodology could then be alternatively applied for the full range slip angle estimation in advanced chassis control applications.

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This paper describes development of a 3-Dimensional Workspace Passive Cobotic Manipulator. The cobot has 3 dimensional workspace (x,y,z). Inspired by previous works of Scooter1 and Extreme Joystick2 cobots, the 3DP Cobotic Manipulator consists of a spherical ball and three steering Cobotic joints and mechanical links. The sphere-rotating axis is constraint to rotate about its own center. The ball has 3 C-space, roll, pitch, and yaw (φ, α, β˜) There is a two-link manipulator attached on top of the ball. The function of this links is to transform a spherical C-space, (φ, α, β) to the end-effector’s C-space (x-y-z).