The principal components and capabilities of Blanche, an autonomous robot vehicle, are described. Blanche is designed for use in structured office or factory environments rather than unstructured natural environments, and it is assumed that an offline path planner provides the vehicle with a series of collision-free maneuvers, consisting of line and arc segments, to move the vehicle to a desired position. These segments are sent to a low-level trajectory generator and closed-loop motion control. The controller assumes accurate knowledge of the vehicle's position. Blanche's position estimation system consists of a priori map of its environment and a robust matching algorithm. The matching algorithm also estimates the precision of the corresponding match/correction that is then optimally (in a maximum-likelihood sense) combined with the current odometric position to provide an improved estimate of the vehicle's position. The system does not use passive or active beacons. Experimental results are reported. >

Blanche-an experiment in guidance and navigation of an autonomous robot vehicle

A forward-facing vision system for a vehicle includes a forward-facing camera disposed in a windshield electronics module attached at a windshield of the vehicle and viewing through the windshield. A control includes a processor that, responsive to processing of captured image data, detects taillights of leading vehicles during nighttime conditions and, responsive to processing of captured image data, detects lane markers on a road being traveled by the vehicle. The control, responsive to lane marker detection and a determination that the vehicle is drifting out of a traffic lane, may control a steering system of the vehicle to mitigate such drifting, with the steering system manually controllable by a driver of the vehicle irrespective of control by the control. The processor, based at least in part on detection of lane markers via processing of captured image data, determines curvature of the road being traveled by the vehicle.

Vision system for vehicle

A vehicular vision system includes a camera having a lens and a CMOS photosensor array having a plurality of photosensor elements. The camera is disposed at an interior portion of a vehicle equipped with the vehicular vision system. The camera one of (i) views exterior of the equipped vehicle through the windshield of the equipped vehicle and forward of the equipped vehicle and (ii) views from the windshield of the equipped vehicle into the interior cabin of the equipped vehicle. A control includes an image processor that processes image data captured by the photosensor array. The image processor processes captured image data to detect an object viewed by the camera. The photosensor array is operable at a plurality of exposure periods and at least one exposure period of the plurality of exposure periods is dynamically variable.

Vehicular vision system

We formulate the kinematic equations of motion of wheeled mobile robots incorporating conventional, omnidirectional, and ball wheels.1 We extend the kinematic modeling of stationary manipulators to accommodate such special characteristics of wheeled mobile robots as multiple closed-link chains, higher-pair contact points between a wheel and a surface, and unactuated and unsensed wheel degrees of freedom. We apply the Sheth-Uicker convention to assign coordinate axes and develop a matrix coordinate transformation algebra to derive the equations of motion. We introduce a wheel Jacobian matrix to relate the motions of each wheel to the motions of the robot. We then combine the individual wheel equations to obtain the composite robot equation of motion. We interpret the properties of the composite robot equation to characterize the mobility of a wheeled mobile robot according to a mobility characterization tree. Similarly, we apply actuation and sensing characterization trees to delineate the robot motions producible by the wheel actuators and discernible by the wheel sensors, respectively. We calculate the sensed forward and actuated inverse solutions and interpret the physical conditions which guarantee their existence. To illustrate the development, we formulate and interpret the kinematic equations of motion of Uranus, a wheeled mobile robot being constructed in the CMU Mobile Robot Laboratory.

Kinematic modeling of wheeled mobile robots

Systems and methods for positioning and navigating an autonomous vehicle (102,310) allow the vehicle (102,310) to travel between locations. A first position estimate (112) of the vehicle (102,310) is derived from satellites (132-170,200-206) of a global positioning system (100A) and/or a pseudolite(s) (105). The pseudolite(s) (105) may be used exclusively when the satellites (132-170,200-206) are not in view of the vehicle (102,310). A second position estimate (114) is derived from an inertial reference unit (904) and/or a vehicle odometer (902). The first and second position estimates are combined and filtered to derive a third position estimate (118). Navigation of the vehicle (102,310) is obtained using the position information (414), obstacle detection and avoidance data (416), and on board vehicle data (908,910).

Integrated vehicle positioning and navigation system, apparatus and method

An active suspension apparatus detects a relative displacement (x) between an axle and a vehicle body, discriminates a road surface state in accordance with the relative displacement and a change rate (x) in unit time which is derived from the relative displacement (x), and optimally controls characteristics of damping forces of hydropneumatic suspensions in accordance with a discrimination result (i.e., a road surface state). This discrimination is performed in accordance with a sum (Ax+Bx) of a signal obtained by multiplying the relative displacement (x) with a predetermined coefficient and a signal obtained by multiplying the change rate (x) with another predetermined coefficient. These coefficients are obtained in accordance with riding comfort against vibrations. The characteristics of the damping force of the hydropneumatic suspension are controlled by controlling the opening of throttle valves disposed between hydropneumatic chambers and actuators.

Active suspension apparatus

An automatically guided vehicle, traveling without fixed guide ways, has been developed In this paper, the construction of the vehicle, the control algorithm, and its general performance are described

An automatic guidance system of a self-controlled vehicle

An automatically guided vehicle, traveling without fixed guide ways, has been developed. In this paper, the construction of the vehicle, the control algorithm, and its general performance are described.

An Automatic Guidance System of a Self-Controlled Vehicle

The tire for automobiles being measured is loaded in advance by the load applying means and the drum is driven to rotate the tire. A displacement of the rotatable shaft produced in response to a variation in the radial force acting between the tire and the drum is detected as a displacement of the movable member. The movable member is movable with respect to the drum about a fulcrum which lies in or is located in the vicinity of a plane including a surface in which the drum and the tire are held against each other. Thus any influence by a moment due to a lateral force imposed on the tire can be eliminated, and the apparatus can measure a radial force variation with precision.

Apparatus for measuring tire uniformity

An active suspension apparatus detects an absolute acceleration Z in a passenger's compartment of a vehicle and a relative displacement X between an axle and a body, calculates an absolute value |Z| of the absolute acceleration, an absolute value |X| of the relative displacement and an absolute value |X| of a rate X of change in relative displacement, multiplies the absolute values |X|, |X|, and |Z| with coefficients A11, A12 and A13, and adding the resultant product to obtain a sum Y=A11|X|+A12|X|+A13|Z.vertline., compares the sum Y with a reference value C for evaluating the predetermined movement of the vehicle, and controls the damping forces of the hydropneumatic springs, thereby improving steering stability and riding comfort.

Yuzo Yamamoto

Papers

Active suspension apparatus

An automatic guidance system of a self-controlled vehicle

An Automatic Guidance System of a Self-Controlled Vehicle

Apparatus for measuring tire uniformity

Adjustable hydropneumatic active suspension apparatus