Automatic guided vehicles require an accurate method and apparatus for determining vehicle velocity. The subject apparatus is associated with a vehicle having at least one surface engaging idler wheel. A resolver produces a rotation angle rate signal having a value responsive to the angular rotation rate of the idler wheel. A resolver-to-digital converter receives the rotation rate angle signal and produces a rotation rate pulse signal. A clock substantially continuously produces clock pulse signals having a predetermined frequency. A counter receives the rotation rate pulse signal and the clock pulse signal and controllably produces a time signal corresponding to the number of clock pulses received over the duration of a predetermined portion of the rotation rate pulse signal. A logic device controllably receives the time signal and produces a vehicle velocity signal.
A method for controllably moving a work implement attached to a work machine. The method includes the steps of inputting a velocity command, determining a plurality of desired cylinder positions as a function of the desired velocity command, and comparing the desired cylinder positions to allowable cylinder positions. The allowable cylinder positions are a function of a combination of the plurality of desired cylinder positions. The method also includes the steps of moving the work implement to a desired work implement position as a function of the desired cylinder positions, and stopping the movement of the work implement in response to at least one desired cylinder position being at a limit defined by a corresponding at least one allowable cylinder position.
A method of determining a speed of a wheel that involves providing a resolver having a rotor and a stator which resolver produces at least one output signal, operatively connecting the rotor to a wheel such that the resolver is rotated by the rotation of the wheel, producing digital signals indicative of a position of the rotor relative to the stator based on the at least one output signal, and calculating a velocity of the wheel from the digital signals. The digital signals may be used alone or in conjunction with analog wheel speed signals. Also a speed sensor for practicing this method.
A system (400) for positioning and navigating an autonomous vehicle (310) allows the vehicle (310) to travel between locations. Position information (432) is derived from global positioning system satellites (200, 202, 204, and 206) or other sources (624) when the satellites (200, 202, 204, and 206) are not in the view of the vehicle (310). Navigation of the vehicle (310) is obtained using the position information (432), route information (414), obstacle detection and avoidance data (416), and on board vehicle data (908 and 910).
Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
